The URL can be used to link to this page

CC 2020-09-22_08h Local Hazard Mitigation Plan_Attachment 1San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan 2019 Update October 2019 ITEM 8.H. - ATTACHMENT 1 wood. Table of Contents San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page i TABLE OF CONTENTS Section 1 Promulgation and Adoption ............................................................................................. 1-1 1.1 County of San Luis Obispo Board of Supervisors 2005 Adoption........................................ 1-1 1.2 County of San Luis Obispo Board of Supervisors 2011 Adoption........................................ 1-2 1.3 San Luis Obispo County Flood Control and Water Conservation District 2013 Adoption ................................................................................................................................................................................ 1-3 1.4 County of San Luis Obispo Board of Supervisors 2013 Adoption........................................ 1-4 1.5 County of San Luis Obispo Board of Supervisors 2019-2020 Plan Adoption Resolution ................................................................................................................................................................................ 1-4 Section 2 Executive Summary ............................................................................................................ 2-1 2.1 Plan Description ....................................................................................................................................... 2-1 2.2 Plan Purpose and Authority ................................................................................................................. 2-2 Section 3 Planning Process ................................................................................................................. 3-1 3.1 Background on Mitigation Planning in San Luis Obispo County ......................................... 3-1 3.2 What’s New in the Plan Update ......................................................................................................... 3-1 3.2.1 Changes in Jurisdictional Participation .......................................................................... 3-2 3.2.2 Plan Section Review and Analysis - 2019 Update ..................................................... 3-2 3.3 Local Government Participation ......................................................................................................... 3-5 3.4 Planning Process ...................................................................................................................................... 3-7 3.4.1 Phase 1: Organize Resources ............................................................................................. 3-8 3.4.2 Phase 2: Assess Risks ........................................................................................................ 3-20 3.4.3 Phase 3: Develop the Mitigation Plan ........................................................................ 3-21 3.4.4 Phase 4: Implement the Plan and Monitor Progress ............................................ 3-22 Section 4 San Luis Obispo County Profile ........................................................................................ 4-1 4.1 County History .......................................................................................................................................... 4-1 4.2 Geography .................................................................................................................................................. 4-1 4.3 Cities and Communities ........................................................................................................................ 4-3 4.4 Population and Demographics Profile ............................................................................................ 4-6 4.4.1 Social Vulnerability ............................................................................................................. 4-10 4.5 Economy ................................................................................................................................................... 4-19 4.6 Climate ...................................................................................................................................................... 4-21 4.7 Transportation Systems ...................................................................................................................... 4-22 4.8 Governing Body ..................................................................................................................................... 4-22 4.9 Land Use ................................................................................................................................................... 4-22 4.10 Development Trends ......................................................................................................................... 4-23 Section 5 Risk Assessment .................................................................................................................. 5-1 5.1 Hazard Identification and Prioritization .......................................................................................... 5-2 5.1.1 Methodology and Results ................................................................................................ 5-2 5.1.2 Disaster Declaration History ............................................................................................ 5-5 5.1.3 Climate Change Considerations Summary ............................................................. 5-10 ••• Table of Contents San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page ii 5.1.4 Overview of Hazard Identification and Risk Assessment .................................. 5-11 5.2 Assest Summary .................................................................................................................................... 5-12 5.2.1 Assets Expsoure ....................................................................................................................... 5-12 5.3 Hazard Analysis and Risk Assessment .......................................................................................... 5-32 5.3.1 Adverse Weather: General ............................................................................................... 5-32 5.3.2 Adverss Weather: Thunderstorm/Heavy Rain/Dense Fog/Freeze ................... 5-35 5.3.3 Adverse Weather: High Wind/Tornado ...................................................................... 5-54 5.3.4 Adverse Weather: Extreme Heat ................................................................................... 5-68 5.3.5 Agricultural Pest Infestation, Plant Disease, Marine Invasive Species and Tree Mortality ................................................................................................................................. 5-78 5.3.6 Biological Agents (Naturally Occurring) ..................................................................... 5-91 5.3.7 Coastal Storm/Coastal Erosion/Sea Level Rise ...................................................... 5-101 5.3.8 Dam Incidents ..................................................................................................................... 5-137 5.3.9 Drought and Water Shortage ...................................................................................... 5-152 5.3.10 Earthquakes, Faults, and Liquefaction....................................................................... 5-168 5.3.11 Flooding ................................................................................................................................ 5-213 5.3.12 Landslides and Debris Flow ........................................................................................... 5-250 5.3.13 Soil Hazards: Land Subsidence .................................................................................... 5-263 5.3.14 Tsunami and Seiche ......................................................................................................... 5-269 5.3.15 Wildfires ................................................................................................................................ 5-281 5.3.16 Hazardous Materials Incidents .................................................................................... 5-297 Section 6 Capability Assessment ....................................................................................................... 6-1 6.1 San Luis Obispo County’s Mitigation Capabilities Overview .................................................. 6-1 6.1.1 San Luis Obispo County’s Regulatory Mitigation Capabilities ............................. 6-3 6.1.2 Combining Designations .................................................................................................. 6-17 6.2 San Luis Obispo County’s Administrative and Technical Mitigation Capabilities ....... 6-18 6.2.1 Department of Planning and Building ........................................................................ 6-18 6.2.2 Office of Emergency Services ......................................................................................... 6-18 6.2.3 Environmental Health Services Division ..................................................................... 6-19 6.2.4 Public Works Department ................................................................................................ 6-19 6.2.5 Local Boards, Commissions, Committees .................................................................. 6-20 6.2.6 State and Federal Programs............................................................................................ 6-21 6.3 San Luis Obispo County’s Fiscal Mitigation Capabilities ....................................................... 6-22 6.4 Hazard Specific Mitigation Capabilities ....................................................................................... 6-23 6.4.1 Adverse Weather capabilities ......................................................................................... 6-23 6.4.2 Agricultural Pest Infestation and Plant Disease Capabilities.............................. 6-23 6.4.3 Biological Agents (Naturally Occurring) Capabilities ............................................ 6-24 6.4.4 Coastal Storm Capabilities ............................................................................................... 6-24 6.4.5 Dam Failure Capabilities ................................................................................................... 6-24 6.4.6 Drought and Subsidence Capabilities ......................................................................... 6-25 6.4.7 Earthquake Capabilities .................................................................................................... 6-26 6.4.8 Flood Capabilities ................................................................................................................ 6-27 6.4.9 Hazardous Materials Capabilities ................................................................................. 6-29 6.4.10 Landslide Risk Reduction Capabilities ........................................................................ 6-30 6.4.11 Tsunami Capabilities .......................................................................................................... 6-30 ••• Table of Contents San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page iii 6.4.12 Wildfire Capabilities ........................................................................................................... 6-31 6.4.13 Climate Change Capabilities ........................................................................................... 6-34 6.5 Opportunities for Enhancement ..................................................................................................... 6-35 Section 7 Mitigation Strategy ............................................................................................................ 7-1 7.1 Goals and Objectives .............................................................................................................................. 7-1 7.2 Identification and Analysis of Mitigation Actions ....................................................................... 7-3 7.2.1 Prioritization Process ............................................................................................................ 7-5 7.3 Mitigation Action Plan ........................................................................................................................... 7-6 7.3.1 Progress of Previous Mitigating Actions....................................................................... 7-7 7.3.2 Updated Mitigation Action Plan ...................................................................................... 7-9 Section 8 Implementation and Monitoring ..................................................................................... 8-1 8.1 Implementation ........................................................................................................................................ 8-1 8.1.1 Role of Hazard Mitigation Planning Committee in Implementation and Maintenance ............................................................................................................................ 8-2 8.1.2 Process for Incorporation into Existing Planning Mechanisms ............................ 8-2 8.2 Maintenance Monitoring and Evaluation ....................................................................................... 8-3 8.2.1 Maintenance/Monitoring Schedule ................................................................................ 8-4 8.2.2 Maintenance and Evaluation Process............................................................................. 8-4 8.2.3 Disaster Proclamation or Declaration ............................................................................ 8-5 8.3 Continued Public Involvement ........................................................................................................... 8-5 List of Jurisdictional Annexes Annex A City of Arroyo Grande Annex B City of Atascadero Annex C City of Grover Beach Annex D City of Morro Bay Annex E City of Paso Robles Annex F City of Pismo Beach Annex G City of San Luis Obispo Annex H Avila Beach CSD Annex I Ground Squirrel Hollow CSD Annex J Heritage Ranch CSD Annex K Los Osos CSD Annex L Nipomo CSD Annex M Oceano CSD Annex N San Miguel CSD Annex O San Simeon CSD Annex P Templeton CSD Annex Q Cayucos Sanitary District Annex R Port San Luis Harbor District Annex S San Luis Obispo Flood Control and Water Conservation District Annex T South San Luis Obispo County Sanitation District List of Appendices Appendix A Hazard Mitigation Planning Committee ••• Table of Contents San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page iv Appendix B Mitigation Categories and Alternatives Appendix C Planning Process Documentation Appendix D Jurisdictional Adoption Resolutions Appendix E Critical Facilities Appendix F Climate Change Adaptation Planning Guide Consistency Summary Appendix G References Acknowledgements San Luis Obispo County Board of Supervisors Debbie Arnold, Chair Adam Hill, Vice Chair Lynn Compton Bruce Gibson John Peschong County Planning & Building Trevor Keith, Director Rob Fitzroy, Deputy Director Airlin Singewald, Division Manager Brian Pedrotti, Supervising Planner Jillian Ferguson, Project Manager Kylie Hensley, Long Range Planner County Office of Emergency Services Joe Guzzardi, Emergency Services Manager Scott Milner, Emergency Services Coordinator Consulting Team - Wood Environment and Infrastructure Solutions, Inc. Jeff Brislawn, Project Manager Scott Field, Senior Planner Dan Gira, Senior Planner Julia Pujo, Senior Planner ••• Table of Contents San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page v Amy Carr, Planner Marta Blanco Castano, GIS Analyst / Planner Kaylan Lamb, Planner Hannah Thomas, Planner Members of the Hazards Mitigation Committee: Rebecca Whiteside, Planning & Building GIS Analyst, County of San Luis Obispo Robert Hill, Sustainability and Natural Resources Official, City of San Luis Obispo Kate Ballantyne, Public Works Deputy Director, County of San Luis Obispo Chris Read, Sustainability Manger, City of San Luis Obispo Mladen Bandov, Public Works Water Resources Engineer, County of San Luis Obispo James Blattler, Administrative Analyst, City of San Luis Obispo Fire Department Lynda Auchinachie, Agriculture Department Environmental Resource Specialist, County of San Luis Obispo Mychal Jones, Plant Superintendent/Chief Plant Operator, South San Luis Obispo County Sanitation District Stephen Lieberman, Fire Chief, City of Arroyo Grande Rick Koon, District Manager, Cayucos Sanitary District Camilla Karamanlis, Program Analyst, City of Arroyo Grande Chris Munson, Facilities Manager, Port San Luis Harbor District Matt Downing, Planning Manager, City of Arroyo Grande Brad Hagemann, General Manager, Avila Beach Community Services District Tom Peterson, Fire Marshall, City of Atascadero Dan Gilmore, General Manager, Ground Squirrel Hollow Community Services District Casey Bryson, Fire Chief, City of Atascadero Scott Duffield, General Manager, Heritage Ranch Community Services District John Peters, Chief of Police, City of Grover Beach Renee Osborne, General Manger, Los Osos Community Services District Steve Knuckles, Fire Chief, City of Morro Bay Rob Roberson, Interim General Manager/Fire Chief, San Miguel Community Services District Matt Vierra, Fire Marshall, City of Morro Bay Scott Young, Assistant Fire Chief, San Miguel Community Services District Jonathan Stornetta, Fire Chief, City of Paso Robles Courtney Murguia, Office Manager – Grace Environmental, San Simeon Community Services District Mike Gruver, Associate Planner, City of Pismo Beach Carey Casciola, Business & Accounting Manager, Oceano Community Services District Keith Aggson, Fire Chief, City of San Luis Obispo Nicole Miller, Account Administrator, Oceano Community Services District Rodger Maggio, Fire Marshall, City of San Luis Obispo Jeff Brilz, General Manager, Templeton Community Services District Bill White, Fire Chief, Templeton Community Services District ••• Section 1 Adoption Resolutions San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 1-1 SECTION 1 ADOPTION RESOLUTIONS The following is a record of adoption of this plan by San Luis Obispo County since its inception in 2005. Jurisdictional adoption resolutions can be referenced in Appendix D. 1.1 County of San Luis Obispo Board of Supervisors 2005 Adoption Adoption by Local Governing Body: §201.6(c)(5) November 1, 2005 To the Citizens, Visitors, Employees, and Officials of San Luis Obispo County: As the costs of damage from natural disasters continue to increase, the County of San Luis Obispo realizes the importance of identifying effective ways to reduce vulnerability to disasters. Natural hazard mitigation plans assist communities in reducing risk from natural hazards by identifying resources, information, and strategies for risk reduction, while helping to guide and coordinate mitigation activities. As a result the County of San Luis Obispo has developed this Local Hazard Mitigation Plan (LHMP) which provides guidance on how to reduce risk from natural hazards. This LHMP works in conjunction with other County plans, including the General Plan, and hazard mitigation plans developed for specific programs such as flood control and fire prevention. This letter promulgates the San Luis Obispo County Local Hazard Mitigation Plan and constitutes the adoption of the Plan. This Local Hazard Mitigation Plan becomes effective on approval by the San Luis Obispo County Board of Supervisors on the date indicated below. Original signed by Shirley Bianchi Chairperson, Board of Supervisors November 1, 2005 County of San Luis Obispo ••• Section 1 Adoption Resolutions San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 1-2 1.2 County of San Luis Obispo Board of Supervisors 2011 Adoption Adoption by Local Governing Body: §201.6(c)(5) August 16, 2011 To the Citizens, Visitors, Employees, and Officials of San Luis Obispo County: As the costs of damage from natural disasters continue to increase, the County of San Luis Obispo continues to realize the importance of identifying effective ways to reduce vulnerability to disasters. Natural hazard mitigation plans assist communities in reducing risk from natural hazards by identifying resources, information, and strategies for risk reduction, while helping to guide and coordinate mitigation activities. As a result the County of San Luis Obispo has developed this updated and revised Local Hazard Mitigation Plan (LHMP) which provides guidance on how to reduce risk from natural hazards. The LHMP works in conjunction with other County plans, including the General Plan, and hazard mitigation plans developed for specific programs such as flood control and fire prevention. This letter promulgates the San Luis Obispo County Local Hazard Mitigation Plan and constitutes the adoption of the Plan. This Local Hazard Mitigation Plan becomes effective on approval by the San Luis Obispo County Board of Supervisors on the date indicated below. Original signed by Adam Hill Chairperson, Board of Supervisors August 16, 2011 County of San Luis Obispo ••• Section 1 Adoption Resolutions San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 1-3 1.3 San Luis Obispo County Flood Control and Water Conservation District 2013 Adoption ••• Adoption by Local Governing Body: §201.6 (c)(5J Deccmu r IO.2013 To the Citizens. Visitors , Employees. and Offic ia ls of San Luis Obispo C(lunty: A· the co. ts of damage from natural disasters continue 10 increase. tin: County of Sa11 Luis Obispo continues to realize the importance of idc11t ifying cffccti e ways lo rc<luce vulnerab ility to disa tcrs . murnl hazard mitigation plan nssist communities in reducing risk from natural hawrds b. identifying re so urces. infonnation, and strntcgics f r risk rcducrion . whi le hclpi11g 10 guide anti coordinate mitigation acti ·i1ics. As a rt'suh. lhc-County of San Luis Obispo has developed this updatc-d and re, ised Local Hazard Mitigation Plan (LHMP) which pro\'idcs guidance on how to reduce risk from natural h.izards. The LHMP ,vorks in conjunction , ith the other Count plans. including the Ge neral Plan. and hazard mitigation plans dc-vclopcd for speci fic programs such as flood co111rol and fire pn:vcn!ion. This letter promulgates 1hc San Luis Obispo County Local Ha1ard Mitigation Plan and rnnstitutcs the adop1ion of the Plan. This Local Hazard Mitigation Plan becomes dfcctin: 011 approval by !he San Luis Obispo Cou111y r-lood Contro l and Water Conse rvation Dis1rict on the !arc indicah:d below. Brul:c GibsCln /\cling Chairl)l!rson. Board or Supervisor: San Luis Obispo ounty Flood Control .'\nd War r Con.crvatio n District December I 0, 1013 Section 1 Adoption Resolutions San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 1-4 1.4 County of San Luis Obispo Board of Supervisors 2013 Adoption 1.5 County of San Luis Obispo Board of Supervisors 2019-2020 Plan Adoption Resolution Placeholder for adoption resolution ••• Adoption by Local Governing Bndy : ~201.6 (c)(5) Di:ccmber I 0. 2013 fo lht• C iti;,cn s, Visitor ·. £::mplt yccs, an d flic iril s of San I .uis <. bispo ou111~ .. A. the costs or damngc from natural disaster~ 1:onti1111c to i111:rcn~e. chc C H11lly or San Luis Obispo continues to realize the i111portnn e or identifying effective wa)s lo rcd111:c ,·11 In rability to disasters . Na111rnl hazard mitigation plan :issisl communities in reducing risk from 1rnn1rnl h,nnrd s b. idcnlil~'in , n.:sources . information. and strategics for risk redu ction , while hdping to guide :ind coordinate mitigati n acti itics. As a re su lt. the ou nty of an Luis Ohispo has developed this updated and revised l .ocnl 1 lazard Mi1ig1ui on Plan (UI /1) which provide. guidance 1111 h~l\\ to rcdu c risr.. rnm natural h;1.i'nrds . The LI IMP w rks in conjunction willt Lhc other County plan , including the General Plan, and haz:ird 111itigati o11 rlans dcvclnred for spcci1k programs such as tlood con1rol an<l fire prevent ion . rhis kucr pro111ulgates the '11 11 Luis Obispo C1Ju111~ al I la1ard 1i1iga1io11 Pla11 and cons1i1u11.:s the ad pt ion of th e Plan. This L cal HaLarJ 1i(ign1i111 Plan b.:c<Hnc cf1cc1ivc on approval hy the San Luis Obispo ounry Board or Supervisor:; n the date indicated below. Bruce Gibsoll I i ' ~ ( I -l .. - 1\cl ing h:iirpcrson, Ruird l)f St1pcr i ·or. Oi:ccmh~r I 0, 20 I Section 2 Executive Summary San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 2-1 SECTION 2 EXECUTIVE SUMMARY 2.1 Plan Description The mounting cost of disaster recovery in the nation and State of California over the past decades has prompted a renewed interest in proactively determining effective ways to minimize hazard vulnerability, Hazard mitigation planning plays an important role in building resilience through identifying vulnerabilities and potential solutions in mitigation actions. The County of San Luis Obispo, its municipalities and its special districts have to develop this local hazard mitigation plan, which underwent a comprehensive update in 2019. The goal of this plan is to arrive at practical, meaningful, attainable and cost-effective mitigation solutions to reduce vulnerability to the identified hazards and ultimately reduce both human and financial losses from hazard events. The following jurisdictions participated in the development of this plan: Lead Jurisdiction: • County of San Luis Obispo Municipalities: • City of Arroyo Grande • City of Atascadero • City of Grover Beach • City of Morro Bay • City of Paso Robles • City of Pismo Beach • City of San Luis Obispo Community Services Districts: • Avila Beach CSD • Ground Squirrel Hollow CSD • Heritage Ranch CSD • Los Osos CSD • Nipomo CSD • Oceano CSD • San Miguel CSD • San Simeon CSD • Templeton CSD Special Districts: • San Luis Obispo County Flood Control and Water Conservation District • Cayucos Sanitary District • Port San Luis Harbor District • South San Luis Obispo County Sanitation District Development of this mitigation plan included assessing mitigation capabilities, securing political support, and soliciting input and approval from each of the involved communities. ••• Section 2 Executive Summary San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 2-2 Risk assessments were performed that identified and evaluated priority natural and human-caused hazards that could impact the County and its jurisdictions. Historical hazard events are described. The future probability of these identified hazards and their impact on communities within the County is described. Vulnerability assessments summarize the identified hazards’ impact to critical structures, infrastructure, and future development. Estimates of potential dollar losses to vulnerable structures are presented. The risk and vulnerability assessments were used to determine mitigation goals and objectives to minimize long-term vulnerabilities to the identified hazards. These goals and objectives were the foundation behind the development of a comprehensive range of specific attainable mitigation actions. This plan was originally developed in 2005, updated in 2011 and 2013, and underwent a comprehensive update in 2019. A significant change to the plan in 2019 was the inclusion of the municipalities and special districts, broadening it from a County-specific plan to a multi-jurisdictional document prepared in coordination with the participating entities and input from the public. This plan entails adopting, implementing, assigning responsibility, monitoring, and reviewing this hazard mitigation plan over time, to ensure the goals and objectives are being achieved and the plan remains a relevant document. 2.2 Plan Purpose and Authority The Disaster Mitigation Act (DMA) of 2000, also commonly known as “The 2000 Stafford Act Amendments” (the Act), constitutes an effort by the Federal government to reduce the rising cost of disasters. The Act stresses the importance of mitigation planning and disaster preparedness prior to an event. Section 322 of the DMA requires local governments to develop and submit mitigation plans in order to qualify for the Federal Emergency Management Agency’s (FEMA) Hazard Mitigation Assistance (HMA) grant program funds. For disasters declared after November 1, 2004, San Luis Obispo County must have a Local Hazard Mitigation Plan (LHMP) approved pursuant to §201.6 in order to receive HMA funding. The LHMP is written to meet the statutory requirements of DMA 2000 (P.L. 106-390), enacted October 30, 2000 and 44 CFR Part 201 – Mitigation Planning, Interim Final Rule, published February 26, 2002. The HMA grants include the Hazard Mitigation Grant Program (HMGP), Pre-Disaster Mitigation (PDM) program, and the Flood Mitigation Assistance (FMA) program. Additional FEMA mitigation funds include the HMGP Post Fire funding associated with Fire Management Assistance Grant (FMAG) declarations, the Building Resilient Infrastructure and Communities (BRIC) funding associated with the 2018 Disaster Recovery Reform Act (DRRA), and the Rehabilitation of High Hazard Potential Dams (HHPD) Grant Program. To facilitate implementation of the DMA 2000, the Federal Emergency Management Agency (FEMA) created an Interim Final Rule (the Rule), published in the Federal Register in February of 2002 at section 201 of 44 CFR. The Rule spells out the mitigation planning criteria for States and local communities. Specific requirements for local mitigation planning efforts are outlined in section §201.6 of the Rule. In March 2013 FEMA released The Local Mitigation Planning Handbook (Handbook) as the official guide for local governments to develop, update and implement local mitigation plans. The Handbook complements and references the October 2011, FEMA Local Mitigation Plan Review Guide (Guide) in order to help “Federal and State officials assess Local Mitigation Plans in a fair and consistent manner.” Local jurisdictions must demonstrate that proposed mitigation actions are based upon a sound planning ••• Section 2 Executive Summary San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 2-3 process that accounts for the inherent risk and capabilities of the individual communities as stated in section §201.5 of the Rule. Throughout the 2019 update of this LHMP the Handbook and Guide was consulted for the purpose of ensuring thoroughness, diligence, and compliance with the DMA 2000 planning requirements. The 2019 update occurred concurrent with the update of the County General Plan Safety Element update to ensure consistency with hazards and mutually reinforcing policies. In addition to following the DMA requirements the update addressed the following State of California legislation requirements that relate to the General Plan and LHMP: • Senate Bill (SB) 379: Requires inclusion of climate adaptation strategies in General Plan Safety Elements and encourages inclusion of climate change discussion in LHMP updates; • SB 1000 requires environmental justice and social equity considerations in the General Plan update; these considerations were also addressed in the inclusion of social vulnerability and related discussion in Section 4 San Luis Obispo County Profile and mitigation action prioritization criteria detailed in Section 7. • Assembly Bill (AB) 2140 which recommends adoption by reference or incorporation of the LHMP into the Safety Element of the General Plan, following LHMP approval. This Local Hazard Mitigation Plan was prepared jointly by the County of San Luis Obispo; the Cities of Arroyo Grande, Atascadero, Grover Beach, Morro Bay, Paso Robles, Pismo Beach, and San Luis Obispo; the Community Services Districts of Avila Beach, Ground Squirrel Hollow, Heritage Ranch, Los Osos, Nipomo, Oceano, San Miguel, San Simeon, and Templeton; and special districts including the San Luis Obispo County Flood Control and Water Conservation District, the Cayucos Sanitary District, the Port San Luis Harbor District, and the South San Luis Obispo County Sanitation District. The risk assessment and mitigation strategies within this plan were developed jointly to benefit all of the above jurisdictions and make them more resilient to future disasters. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-1 SECTION 3 PLANNING PROCESS 3.1 Background on Mitigation Planning in San Luis Obispo County The primary purpose of the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan (LHMP) update is to reduce or eliminate long-term risk to people and property from natural hazards and their effects on the San Luis Obispo County planning area. San Luis Obispo County recognized the need and importance of a Local Hazard Mitigation Plan (LHMP) and initiated its development in 2005 after receiving a grant from the Federal Emergency Management Agency (FEMA), which also served as the primary funding source for this plan. The original LHMP was developed in 2005, updated in 2011, and most recently in 2013 with final approval from FEMA in 2014. Additional details on the previous planning effort can be referenced in the 2014 Plan. The plan underwent a comprehensive update in 2019. The planning process followed during the update was similar to what was used in the original plan development. This planning process utilized the input from a multi-jurisdictional Hazard Mitigation Planning Committee (HMPC). A significant change from the 2014 Plan is the inclusion of all of the incorporated communities within the planning area (seven), nine community service districts, and four special districts. Wood Environment & Infrastructure Solutions, Inc (Wood) was procured to assist with the update in 2019. The process is described further in this section and documented in Appendix C. 3.2 What’s New in the Plan Update DMA Requirement §201.6(d)(3): A local jurisdiction must review and revise its plan to reflect changes in development, progress in local mitigation efforts, and changes in priorities, and resubmit it for approval within 5 years in order to continue to be eligible for mitigation project grant funding. The updated LHMP complies with Federal Emergency Management Agency (FEMA) guidance and California Office of Emergency Services guidelines for Local Hazard Mitigation Plans. The update followed the requirements noted in the Disaster Mitigation Act (DMA) of 2000 and FEMA’s 2013 Local Hazard Mitigation Planning Handbook. DMA Requirements §201.6(b) and §201.6(c)(1): An open public involvement process is essential to the development of an effective plan. In order to develop a more comprehensive approach to reducing the effects of natural disasters, the planning process shall include: (1)An opportunity for the public to comment on the plan during the drafting stage and prior to plan approval; (2)An opportunity for neighboring communities, local and regional agencies involved in hazard mitigation activities, and agencies that have the authority to regulate development, as well as businesses, academia, and other private and non-profit interests to be involved in the planning process; and (3)Review and incorporation, if appropriate, of existing plans, studies, reports, and technical information. [The plan shall document] the planning process used to develop the plan, including how it was prepared, who was involved in the process, and how the public was involved. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-2 This LHMP update involved a comprehensive review and update of each section of the 2014 plan and includes an assessment of the progress in evaluating, monitoring and implementing the mitigation strategy outlined in the initial plan. The planning process provided an opportunity to review jurisdictional priorities related to hazard significance and mitigation action, and revisions were made where applicable to the plan and the municipal annexes. Another major change in priority was the desire to expand the LHMP into a multi-jurisdictional plan (see subsection 3.2.1). Only the information and data still valid from the 2014 plan was carried forward as applicable into this LHMP update. 3.2.1 Changes in Jurisdictional Participation A significant change to the 2019 Plan is that it is now a multi-jurisdictional HMP. Previously in the 2014 Plan, the only additional jurisdiction covered by the LHMP was the San Luis Obispo County Flood Control and Water Conservation District (FCWCD). The FCWCD continued to participate in the 2019 planning process, in addition to four (4) other special districts, nine (9) community service districts (CSD) and participation from all seven (7) incorporated municipalities in the County. The municipalities previously had been covered by separate LHMPs. All of the municipalities previously had local hazard mitigation plans, which were used as the basis to inform and update jurisdictional annexes. As such, this Plan constitutes an LHMP update for those jurisdictions and also for the County, County FCWCD, Los Osos CSD and the South San Luis Obispo County Sanitation District, which were also covered by previous LHMPs. One Community Service District (CSD), Oceano, had recently completed and submitted its LHMP to FEMA for approval in 2019; this plan was approved by FEMA in 2019 as a single jurisdictional plan. The LHMP is included in its entirety as an annex for easy reference and coordination on mitigation activities, and to be considered for inclusion as part of the next five year update of the County multi-jurisdictional HMP. The Cambria CSD and Cambria Healthcare District have a FEMA-approved LHMP (February 2018) and are not covered in this plan. This Plan constitutes a new LHMP for the following jurisdictions: Community Service Districts: •Avila Beach CSD •Ground Squirrel Hollow CSD •Heritage Ranch CSD •Nipomo CSD •San Miguel CSD •San Simeon CSD •Templeton CSD Special Districts: •Cayucos Sanitary District •Port San Luis Harbor District 3.2.2 Plan Section Review and Analysis - 2019 Update During the 2019 plan update, the HMPC updated each of the sections of the previously approved plan to include new information. Wood developed a summary of each section in the plan and guided the HMPC through the elements that needed updating during the kickoff meeting in January 2019. This included analyzing each section using FEMA’s local plan update guidance (2013) to ensure that the plan met the latest requirements. In addition, the FEMA Local Mitigation Plan Review Tool that was provided with the ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-3 approval of the 2014 version of this plan was reference, in particular the 2014 FEMA comments on opportunities for improvement were considered and addressed in the 2019 update. The HMPC and Wood determined that nearly every section of the plan would need revision to align the plan with the latest FEMA planning guidance and requirements. A summary of the changes in this plan update is highlighted in the table below. Table 3-1 San Luis Obispo County Hazard Mitigation Plan Update Highlights Plan Section Summary of Plan Review, Analysis, and Updates 1. Promulgation and Adoption Includes history of previous adoptions Plan will be re-adopted as part of the update process 2. Introduction and Executive Summary Revised to reflect updated plan and 2019 planning process 3.Planning Process Describes and documents the planning process for the 2019 update, including coordination among agencies Describes how 2014 plan was integrated with/into other planning efforts. Removed 2014 planning process info. Describes changes to jurisdictional participation Describes 2019 public participation process Describes the Hazard Mitigation Planning Committee Describes the 10 step process followed for the update 4. County Profile Updated with recent census data and current economy description Updated land use and development trends 5.Hazard Assessment Drought and Coastal Storm are now profiled as separate hazards and are no longer part of Adverse Weather Extreme heat has been added as a hazard under Adverse Weather Marine invasive species has been added to Agricultural pest infestation and plant disease Vector borne disease has been added to Biological Agents Discussion on levee failure has been added to Flood Debris Flow has been added to Landslides Coastal storms and sea level rise have been added to Coastal Erosion Subsidence was added as a standalone hazard profile Climate change information has been added to each hazard profile Updated list of disaster declarations to include recent data. Updated tables to include recent National Center for Environmental Information data. Updated past occurrences for each hazard to include recent data. 5. Risk Assessment 2014 Plan on Vulnerability Assessment is now included with the Risk Assessment section as subsections by hazard. Updated critical facilities identified from the 2014 plan. Updated growth and development trends to include recent Census and local data sources. Updated historic and cultural resources using local/state/national sources. Updated property values for vulnerability and exposure analysis, using updated building information based on assessor’s data. Updated estimate flood losses using the latest Digital Flood Insurance Rate Map (DFIRM) and assessor’s data. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-4 Plan Section Summary of Plan Review, Analysis, and Updates Updated National Flood Insurance Program (NFIP) data and Repetitive Loss structure data from the previous plan. Incorporated new hazard loss estimates since 2014, as applicable. Used updated GIS inventory data to assess wildfire threat to the County Updated HAZUS-MH Level I earthquake vulnerability analysis data Updated information regarding specific vulnerabilities to hazards, including maps and tables of specific assets at risk, specific critical facilities at risk, and specific populations at risk. Updated maps in plan where appropriate. 6.Capability Assessment Reviewed mitigation capabilities and update to reflect current capabilities. Added capability summary tables for regulatory, administrative/technical, and fiscal mitigation capabilities. Added capabilities for new hazards profiled in Section 5. Added information on how capabilities could be expanded or enhanced. 7.Mitigation Strategy Indicated what actions have been implemented that may reduce previously identified vulnerabilities. Updated mitigation strategy based on the results of the updated risk assessment, completed mitigation actions, and implementation obstacles and opportunities since the completion of the 2014 plan. Reviewed and updated goals and objectives based on HMPC input. Included updated information on how actions are prioritized, or how priorities changed. Reviewed mitigation actions from the 2014 plan and developed a status report for each; identified if actions have been completed, deleted, or deferred/carried forward. Updated priorities on actions. Identify examples of successful implementation to highlight positive movement on actions identified in 2014 plan. Identified new mitigation actions proposed by the HMPC with more detail on implementation than the previous plan. Developed a summary table of mitigation actions for all participating jurisdictions. 8.Implementation and Monitoring Reviewed and updated procedures for monitoring, evaluating, and updating the plan. Revised to reflect current methods. Updated the system for monitoring progress of mitigation activities by identifying additional criteria for plan monitoring and maintenance. Added a process for incorporation of the HMP into existing mechanisms Jurisdictional Annexes Developed annexes for new participating jurisdictions in 2019. Moved previous information in 2014 plan on San Luis Obispo County Flood Control and Water Conservation District into jurisdictional annex A City of Arroyo Grande B City of Atascadero C City of Grover Beach D City of Morro Bay E City of Paso Robles F City of Pismo Beach G City of San Luis Obispo H Avila Beach CSD ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-5 Plan Section Summary of Plan Review, Analysis, and Updates I Ground Squirrel Hollow CSD J Heritage Ranch CSD K Los Osos CSD L Nipomo CSD M Oceano CSD N San Miguel CSD O San Simeon CSD P Templeton CSD Q SD - Cayucos Sanitary District R SD - Port San Luis Harbor District S SD - San Luis Obispo FCWCD T SD - South San Luis Obispo County Sanitation District Appendices Appendix A: Hazard Mitigation Planning Committee Appendix B: Mitigation Categories, Alternatives, and Selection Criteria Appendix C: Planning Process Documentation Appendix D: Jurisdiction Adoption Resolutions Appendix E: Critical Facilities Appendix F: Climate Change Adaptation Planning Guide Consistency Summary Appendix G: Climate Change Adaptation and Resilience Statutory Consistency Summary Appendix H: References 3.3 Local Government Participation In the 2019 plan update, the following jurisdictions participated in the planning process and will be adopting the updated plan following FEMA approval. As noted previously, all participants are new to the SLO County LHMP except for San Luis Obispo Flood Control and Water Conservation District which participated in the 2014 planning process. All incorporated cities in the County participated in this planning process as well as four (4) special districts, nine (9) community service districts (CSD. The County and the municipalities have the authority to regulate development within their jurisdictions; the County has authority for regulating development within the unincorporated areas including the CSDs. Lead Jurisdiction: •County of San Luis Obispo Municipalities: •City of Arroyo Grande •City of Atascadero •City of Grover Beach •City of Morro Bay •City of Paso Robles •City of Pismo Beach •City of San Luis Obispo Community Service Districts: •Avila Beach CSD ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-6 •Ground Squirrel Hollow CSD •Heritage Ranch CSD •Los Osos CSD •Nipomo CSD •San Miguel CSD •San Simeon CSD •Templeton CSD Special Districts: •San Luis Obispo County Flood Control and Water Conservation District •Cayucos Sanitary District •Port San Luis Harbor District •South San Luis Obispo County Sanitation District The DMA planning regulations and guidance stress that each local government seeking FEMA approval of their mitigation plan must participate in the planning effort in the following ways: •Participate in the process as part of the HMPC •Detail areas within the planning area where the risk differs from that facing the entire area •Identify potential mitigation actions •Formally adopt the plan For the San Luis Obispo County planning area’s HMPC, “participation” meant the following: •Providing facilities for meetings •Attending and participating in the HMPC meetings •Completing and returning Wood Plan Update Guide worksheets •Collecting and providing other requested data (as available) •Identifying mitigation actions for the plan •Reviewing and providing comments on plan drafts and jurisdictional annexes •Informing the public, local officials, and other interested parties about the planning process and providing opportunity for them to comment on the plan •Coordinating, and participating in the public input process •Coordinating the formal adoption of the plan by the governing boards The County and all jurisdictions with annexes to this plan and seeking FEMA approval met all of these participation requirements. In most cases one or more representatives for each jurisdiction attended the multi-jurisdictional meetings described in Table 3.2 Schedule of Planning Meetings and brought together a local planning team to help collect data, identify mitigation actions and implementation strategies, and review and provide data on annex drafts. In some cases, the jurisdictions had limited capacity to attend or had conflicts with HMPC meetings; in these cases, alternative forms of communication were used to provide input into the process. Appendix C provides additional information and documentation of the planning process. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-7 3.4 Planning Process Wood established the planning process for the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan using the DMA planning requirements and FEMA’s associated guidance. The original FEMA planning guidance is structured around a four-phase process: 1.Organize Resources 2.Assess Risks 3.Develop the Mitigation Plan 4.Implement the Plan and Monitor Progress Into this process, Wood integrated a more detailed 10-step planning process used for FEMA’s Community Rating System (CRS) and Flood Mitigation Assistance programs. Thus, the modified 10-step process used for this plan meets the requirements of major grant programs including: FEMA’s Hazard Mitigation Grant Program, Pre-Disaster Mitigation program, Flood Mitigation Assistance Program, and flood control projects authorized by the U.S. Army Corps of Engineers. In 2013, FEMA released the Local Mitigation Planning Handbook that has become the official guide for local governments to develop, update and implement local mitigation plans. While the requirements under §201.6 have not changed, the Handbook provides guidance to local governments on developing or updating hazard mitigation plans to meet the requirements under the Code of Federal Regulations (CFR) Title 44 – Emergency Management and Assistance §201.6, Local Mitigation Plans for FEMA approval and eligibility to apply for FEMA Hazard Mitigation Assistance grant programs. It also offers practical approaches, tools, worksheets and local mitigation planning examples for how communities can engage in effective planning to reduce long-term risk from natural hazards and disasters. The Handbook complements and liberally references the Local Mitigation Plan Review Guide (October 1, 2011), which is the official guidance for Federal and State officials responsible for reviewing local mitigation plans in a fair and consistent manner. Table 3-2 shows how the modified 10-step process fits into FEMA’s four-phase process, and how these elements correspond to the tasks in the FEMA Mitigation Planning Handbook. Table 3-2 San Luis Obispo County Hazard Mitigation Planning Process FEMA’s 4-Phase DMA Process Modified 10-Step CRS Process FEMA Local Mitigation Planning Handbook Tasks 1) Organize Resources 201.6(c)(1) 1) Organize the Planning Effort 1: Determine the planning area and resources 201.6(b)(1) 2) Involve the Public 2: Build the planning team - 44 CFR 201.6 (C)(1) 201.6(b)(2) and (3) 3) Coordinate with Other Departments and Agencies 3: Create an outreach strategy - 44 CFR 201.6(b)(1) 4: Review community capabilities - 44 CFR 201.6 (b)(2)&(3) 2) Assess Risks 201.6(c)(2)(i) 4) Identify the Hazards ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-8 FEMA’s 4-Phase DMA Process Modified 10-Step CRS Process FEMA Local Mitigation Planning Handbook Tasks 201.6(c)(2)(ii) 5) Assess the Risks 5: Conduct a risk assessment - 44 CFR 201.6 (C)(2)(i) 44 CFR 201.6(C)(2)(ii)&(iii) 3) Develop the Mitigation Plan 201.6(c)(3)(i) 6) Set Goals 6: Develop a mitigation strategy - 44 CFR 201.6(c)(3)(i); 44 CFR 201(c)(3)(ii) and 44 CFR 201.6(c)(3)(iii) 201.6(c)(3)(ii) 7) Review Possible Activities 201.6(c)(3)(iii) 8) Draft an Action Plan 4) Implement the Plan and Monitor Progress 201.6(c)(5) 9) Adopt the Plan 7: Review and adopt the plan 201.6(c)(4) 10) Implement, Evaluate, and Revise the Plan 8: Keep the plan current 9: Create a safe and resilient community - 44 CFR 201.6(c)(4) 3.4.1 Phase 1: Organize Resources Planning Step 1: Organize the Planning Effort The 2019 planning process and update of the LHMP had its roots in the development of a grant application. The County Office of Emergency Services (OES) wrote the grant and in the process solicited commitments from local government jurisdictions that were interested in participating. With an understanding of the number of jurisdictions and their commitment to participate, the grant application was approved and awarded to the County in 2018. A request for proposals was utilized to bring on a qualified planning consultant. The update process was formally initiated in January 2019 under the coordination of the County of San Luis Obispo Planning & Building Department as the lead entity, in coordination with OES, so that the effort could be coordinated with a parallel effort to update the General Plan Safety Element. Wood worked with the Planning & Building staff and OES to establish the framework and organization for development of the plan. Wood assisted County staff with coordination with other governmental agencies and public process elements to develop the updated LHMP for San Luis Obispo County. Organizational efforts were initiated with a series emails to inform and educate jurisdictions within the County of the purpose and need for an update to the countywide hazard mitigation plan. Representatives from participating jurisdictions and HMPC members from the 2014 plan were used as a starting point for the invite list, with additional invitations extended as appropriate throughout the planning process. The HMPC was re-established as a result of this effort. Membership of the HMPC is detailed in Appendix A. Planning Meetings The planning process officially began with a kickoff meeting on January 25, 2019. The meeting covered the scope of work and an introduction to the DMA requirements. Participants were provided with a Local Hazard Mitigation Plan Update Workbook, which included worksheets to facilitate the collection of information necessary to support update of the plan. Using FEMA guidance, Wood designed these worksheets to capture information on past hazard events, identify hazards of concern to each of the participating jurisdictions, quantify values at risk to identified hazards, inventory existing capabilities, and ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-9 record possible mitigation actions. A copy of Wood’s Local Hazard Mitigation Plan Update Guide for this project is included in Appendix C. The County and each jurisdiction seeking FEMA approval of their plan completed and returned the worksheets in either the Local Hazard Mitigation Plan Update Workbook or shared their most recent local hazard mitigation plan for incorporation into the plan document. During the planning process, the HMPC communicated through face-to-face meetings, email, and telephone conversations. Draft documents were posted on a Google Drive and in some cases emailed so that the HMPC members could easily access and review them. The HMPC formally met four times during the planning period (January 25, 2019 – April 30, 2019). The purposes of these meetings are described in Table 3.2. The planning consultant sent meeting handouts ahead of time to the participating jurisdictions to review and provide feedback before or at the meeting. In addition to these meetings some jurisdictions held meetings with subcommittees to discuss the needed input for the plan update. In a couple cases some municipalities were not able to attend the planning workshops due to scheduling conflicts or limited staff capacity. A planner in the County Planning & Building Department – Long Range Division and the planning consultant worked with the jurisdictions individually in those cases to obtain necessary information and input into the planning process. This was done through direct emails from the planning consultant and follow-up phone conversations with the consultant and the County Planner where necessary. Table 3-3 Schedule of Planning Meetings Meeting Type Meeting Topic Meeting Date(s) Meeting Location(s) HMPC #1 Kick-off meeting: introduction to DMA, the planning process, planning for public involvement and hazard identification January 25, 2019 San Luis Obispo HMPC #2 Hazard Identification and Risk Assessment results, capability assessment updates March 19, 2019 San Luis Obispo HMPC #3 Update of mitigation goals and objectives, capabilities, previous mitigation action progress April 25, 2019 San Luis Obispo HMPC #4 Development and prioritization of mitigation action recommendations April 30, 2019 San Luis Obispo HMPC Meeting #1 -Kickoff Meeting On January 25, 2019, the Planning Team convened in person to discuss the process for completing the update of this plan. The kickoff meeting was well attended with thirty-three (33) individuals present. The audience was a mix of county departments, local governments, special districts and stakeholders. Representatives from the County department included: Planning & Building, Office of Emergency Services, Public Works and the Agricultural Department. All participating municipalities and Community Service Districts had representatives present at the meeting. Stakeholders present at the meeting included representatives from the San Luis Obispo County Fire Safe Council, and a Professor of City and Regional Planning from Cal Poly, San Luis Obispo. A complete list of those in attendance at the kickoff meeting can be found in the sign-in sheets in Appendix C. Following introductions, Wood reviewed the DMA requirements and the suggested planning process to follow to meet the requirements as well as the expected schedule of the process. The roles of the HMPC and stakeholder was discussed including the participation requirements for the different roles. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-10 During the kickoff meeting the Planning Team validated the identified hazards within the 2014 plan with minor revisions and collaboratively prioritized the hazards for the purpose of identifying which are “of most concern” to the County. More details are included in Section 5 Risk Assessment. The group also discussed other agencies that should be part of this planning process, as well as related planning efforts to be coordinated with and recent studies to be incorporated. Part of this discussion was also related to creating a public outreach strategy to involve the public throughout the planning process. Suggestions on public involvement tools included, •Outreach through social media •Posting information on local government websites •Utilize City of San Luis Obispo’s City Hall web platform •Create and disseminate an online public survey The kickoff meeting ended with Wood sharing handouts to assist in the planning process. These handouts included the Local Hazard Mitigation Plan Update Workbook which outlined data collection needs for each participating jurisdiction. HMPC Meeting #2 – Risk and Goals On March 19, 2019, the HMPC convened in person to discuss the results of the risk and vulnerability assessment. Twenty-four (24) members of the HMPC were present for the discussion. Wood began the meeting with a presentation on the results the risk assessment for natural hazards, results for hazardous material incidents were presented at the next meeting. A handout summarizing the hazard significance for each jurisdiction was shared for Planning Team to review. The group went through each hazard together and discussed the results as well as shared any local insight to inform the HIRA update. Refer to the meeting summary in Appendix C for notes related to each hazard discussed. Part of this discussion was also related to development trends. Following the discussion on the results of the risk assessment, the group was provided a handout that summarized current goals and objectives from the County HMP, jurisdictional HMPs and the State HMP. Wood explained this update process provides an opportunity to review the previous plan’s goals to determine if they are still valid, comprehensive, and reflect current priorities and updated risk assessment. The group was also encouraged to share their jurisdiction’s goal statements with their local planning teams prior to the next meeting to discuss if changes are necessary. Wood shared with group that the online public survey had been opened and already received thirty (30) responses at that time. A link was shared with the HMPC to easily distribute by email and for posting on websites. The meeting ended with a review of the next steps and planning process schedule. HMPC Meeting #3 – Goals, Capabilities, and Action Status The HMPC reconvened on April 25, 2019 to discuss goal revisions and updates, updates to the capability assessment and status of mitigation actions from the previous County and jurisdictional HMPs. The meeting began with a status update of the planning process and a review of the additional vulnerability assessment data related to hazardous material incidents. This was followed by discussion on the revised goals, with some additional adjustments suggested by the group. The capability assessment update was also discussed; it was emphasized that each jurisdiction should consider options for enhancing or ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-11 expanding their mitigation capabilities. Progress on mitigation actions was also summarized in anticipation of developing new actions in a subsequent meeting. HMPC Meeting #4 – Mitigation Action Workshop On April 30th, 2019, the HMPC convened in person to identify new mitigation actions to include in the updated plan. This encompassed a review of possible mitigation activities, alternatives, and related climate adaptation strategies. The group also discussed criteria for mitigation action selection and prioritization. This was followed by a brainstorming session to elicit the development of new mitigation actions. Entities responsible for new mitigation action implementation were identified. A sticky dot exercise was used as an initial prioritization on the new mitigation actions. Mitigation action worksheets were distributed to allow additional details to be added following the workshop. Planning Step 2: Involve the Public Involving the public assures support from the community at large and is a required part of the planning process per the DMA 2000. Early discussions with the San Luis Obispo County planning staff and input received in the first HMPC meeting established the initial plan for public involvement in the plan update. Public outreach began with the creation of an online public survey that was shared with each participating jurisdiction to post on their websites and disseminate via email to local stakeholders. The public outreach activities described here were conducted with participation from and on behalf of all jurisdictions participating in this plan. Throughout the planning process public workshops were held to inform the public of the purpose of the DMA and the hazard mitigation planning process for the San Luis Obispo County planning area. At each workshop the public in attendance were provided comment cards to leave any comments related to the County’s Hazard Mitigation Plan as well as provide their contact information if they would like to receive ongoing updates and information related to the planning process. At the kick-off meeting, the HMPC discussed additional options for public involvement and agreed to an approach using established public information mechanisms and resources within the community. Public involvement activities included press releases, website postings, flyer development and distribution, public meetings, and the collection of public comments on the draft plan. To promote the first workshop County staff reached out to local media outlets to inform the public of the opportunity to participate and posted on several community calendars. Posts were created on the following community calendars: •KSBY •KCBX •KEYT/ KCOY •New Times/Santa Maria Sun •Paso Robles Daily News •Santa Maria Times •Tribune •Cambrian News •Pacific Coast Business Times County-wide stakeholders were identified, and invites were also sent to: •Cal Poly MCRP Professors ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-12 •Cambria CSD •SLO Fire Safe Council •California Department of Corrections and Rehabilitation - Associate Warden California Men’s Colony (CMC) •Department of State Hospitals •Xolon Salinan Tribe •Tenet Health •SLO COG •Coastal Commission •Head of Safety Committee Cayucos •Safety and Emergency Plans Templeton •Paso Robles Joint Unified School District •San Luis Coastal Unified School District •Assistant Superintendent, Lucia Mar Schools Figure 3-1 below is the flyer the County HMPC used to advertise the first public workshop on March 19,2019. Press releases can be found in Appendix C. Figure 3-1 San Luis Obispo County’s Flyer for Public Workshop #1, March 19, 2019 wood. ••• Snacks will be provided! Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-13 Online Public Survey During the plan update’s drafting stage, an online public survey was developed as a tool to gather public input. The survey was for the public to provide feedback to the San Luis Obispo County Multi- jurisdictional Hazard Mitigation Planning Committee on reducing hazard impacts. The survey provided an opportunity for public input during the planning process, prior to finalization of the plan update. The survey gathered public feedback on concerns about hazards and input on strategies to reduce their impacts. The survey was released in March and closed on May 14th. The HMPC provided links to the public survey by distributing it using social media, email, and posting the link on websites. The County provided laptops that could be used to fill out the survey at the first public meeting, as well as flyers with the survey link as handouts. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-14 Figure 3-2 Example of Public Survey Response Three hundred and twenty-two (322) people filled out the survey online. Results showed that the public perceives the most significant hazards to be wildfire, earthquake and drought and water shortage. Figure 3-1 above, shows the responses to question 3 of the survey, which solicited the public’s opinion on the mitigation actions that should have the highest priority in the updated hazard mitigation plan. Wildfire fuels treatment projects, evacuation route development, hazardous tree removal, and public education and awareness of hazards were cited as the most popular mitigation actions. This information was shared Wildfire Fuels Treatment ... Assistance with De fens i ••• Continued Participatio .•. Critical Facilities •.. Generators for critrcal ... Planning/Zoning Public Education/Aw ... Stormwater Drainage ... Forest Health/Water .•. Flood Mitigation Education and Discounts on ... Floodprone Pmperty Buyout Public Education/ ... Warning and Notification ... Landslide/muds! ide mitigation Evacuation route ... Hazardous Tree Removal ••• 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-15 with the HMPC during the update of the mitigation strategy as a source of potential mitigation ideas. A summary of all the survey data and documentation of the public feedback can be found in Appendix C. Public Workshops Two public workshops were held during the planning process to inform the public, receive input to integrate into the plan update and keep the public updated on the progress being made in the planning process. The first workshop was held on March 19, 2019 with fifteen (15) members of the public were present. The intent of the first was to introduce the public to the hazard mitigation planning process for the County’s Plan Update as well as answer any questions and gather public input to be integrated into the plan update. In addition it was an opportunity to help staff identify risks, hazards and vulnerabilities from the public’s perspective. The HMPC received three comment cards from meeting that helped to inform the Planning Team on the public initial thoughts on hazard mitigation and hazards in their community each can be found in Appendix C. The second public workshop was held on April 30, 2019 and was well attended with thirteen members of the public, as well as stakeholders from Cal Poly and the County Farm Bureau. The primary intent of the second workshop was to gather feedback on mitigation strategies to reduce the identified hazard vulnerabilities, answer questions and collect input to share with the HMPC. This workshop was also an opportunity to inform the public on the Safety Element update of the County’s General Plan and how that effort related to the County’s Hazard Mitigation Plan. Two local news stations (KEYT and KSBY) were also present at the meeting and each reported on the planning process and shared the link to the online public survey in TV broadcast segments the following morning. Example press releases and sign in sheets are located in Appendix C. Prior to finalizing the plan the draft was available online on the San Luis Obispo County website. Table 3-4 Public Meeting Schedule Meeting Topic Meeting Date Meeting Location Introduce the Disaster Mitigation Act of 2000 and the hazard mitigation planning process for the County’s plan update. Reviewed the results of the risk assessment and discussed mitigation action strategies. March 19, 2019 San Luis Obispo Library, City of San Luis Obispo Discuss and gather feedback on mitigation strategies to reduce identified hazard vulnerabilities, answer questions and collect input to share with the HMPC for the plan update. Shared the progress on the update to the General Plan Safety Element and how it relates to the HMP. April 30, 2019 Ludwick Community Center, City of San Luis Obispo Introduce public review draft of plan and solicit feedback. October 14, 2019 November 15, 2019 Public Review Period On October 14, 2019, a public review draft of this plan was released for comment and made available for download via the County Planning & Building Department website. Comments were collected through November 13, 2019. The draft plan was advertised through social media, mass emailing and an advertisement through the media mechanisms noted previously. An electronic comment form through ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-16 SurveyMonkey was provided with the draft plan. Two comments were received and are documented in Appendix C. One comment received related to providing evacuation routes and integrate evacuation planning into this plan. While detailed evacuation routes are outside the scope of this plan, the County does have a number of evacuation plans which are noted in subsection 6.1 that include hazard-specific plans for dam and levee failure, wildfire (West Atascadero, Parkhill, Avila, Cambria, Upper Los Berros, Suey Creek), tsunami, and Diablo Canyon radiological incidents. The former Director of the County’s Office of Emergency Services also reviewed and provided input to the committee on portions of Section 4, Community Profile and Section 5 Hazard Identification and Risk Assessment; this resulted in edits in those sections to clarify correct or enhance the existing information where applicable. Planning Step 3: Coordinate with Other Departments and Agencies Early in the planning process, state and local agencies and organizations were invited to participate as stakeholders in the process. Stakeholders include local and regional agencies involved in hazard mitigation activities or those beyond the County and local government that have the authority to regulate development, including the California Coastal Commission and the Xolon Salinan Tribe. Stakeholders could participate in various ways, either by contributing input at HMPC meetings, being aware of planning activities through an email group, providing information to support the effort, or reviewing and commenting on the draft plan. Based on their involvement in other hazard mitigation planning efforts, and status in the County, representatives from the following agencies and organizations were invited to participate as stakeholders in the process; an asterisk indicates they participated in HMPC meetings: •Cal Poly, San Luis Obispo* •Cambria CSD •Oceano CSD* •SLO Fire Safe Council* •Associate Warden CMC •Department of State Hospitals* •Xolon Salinan Tribe •Tenet Health •San Luis Obispo Council of Governments (SLOCOG) •Coastal Commission •Retired Cal Poly professor/citizen* The majority of the listed stakeholders were invited to participate in the planning process, which included an invitation to attend the kickoff meeting. Several opportunities were provided for the above groups to participate in the planning process. At the beginning of the planning process, invitations were extended to these groups via an email from the Planning & Building staff project manager to actively participate on the HMPC. They were also invited via email to the public meetings discussed previously. Coordination with key agencies, organizations, and advisory groups throughout the planning process allowed the HMPC to review common problems, development policies, and mitigation strategies as well as identifying any conflicts or inconsistencies with regional mitigation policies, plans, programs and regulations. Phone calls and emails were used during plan development to directly coordinate with key individuals representing other regional programs. As noted by the asterisks next to the above names, many of these groups found it beneficial to participate on the HMPC or attend public meetings. Others assisted in the process by providing data directly as ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-17 requested in the Local Hazard Mitigation Plan Update Guide or through data contained on their websites. Further as part of the both HMPC and public outreach processes, all groups were invited to review and comment on the plan prior to submittal to Cal OES and FEMA. As part of the public review and comment period for the draft plan, key agencies were again specifically solicited to provide any final input to the draft plan document. This input was solicited both through membership on the HMPC and by direct emails to key groups and associations to review and comment on the plan. As part of this targeted outreach, these key stakeholders were also specifically invited to attend the HMPC and public meeting to discuss any outstanding issues and to provide input on the draft document and final mitigation strategies. In summary, several opportunities were provided for the groups listed above to participate in the planning process. At the beginning of the planning process, invitations were extended to these groups to actively participate on the HMPC. Specific participants from these groups are detailed in Appendix A. Others assisted in the process by providing data directly as requested or through data contained on their websites or as maintained by their offices. Further as part of the public outreach process, all groups were invited to attend the public meetings and to review and comment on the plan prior to submittal to Cal OES and FEMA. In addition, as part of the review of the draft plan, key agency stakeholders were contacted, and their comments specifically solicited. Emergency managers in adjacent counties (Kern, Monterey, and Santa Barbara) were contacted by the County emergency services coordinator via email and asked to provide comments on the public review draft of the plan. The Emergency Manager for Santa Barbara County provide comments during this review period. The comments were integrated into Section 4 Community Profile to provide clarity and make the plan more accurate. This process accomplished as part of planning steps two and three in the FEMA Local Mitigation Planning Handbook. Incorporation of Existing Plans and Other Information The coordination and synchronization with other community planning mechanisms and efforts are vital to the success of this plan. To have a thorough evaluation of hazard mitigation practices already in place, appropriate planning procedures should also involve identifying and reviewing existing plans, policies, regulations, codes, tools, and other actions are designed to reduce a community’s risk and vulnerability from natural hazards. San Luis Obispo County uses a variety of mechanisms to guide growth and development. Integrating existing planning efforts, mitigation policies, and action strategies into this plan establishes a credible, comprehensive document that weaves the common threads of a community’s values together. The development and update of this plan involved a comprehensive review of existing plans, studies, reports, and initiatives from the County of San Luis Obispo and each participating municipality that relate to hazards or hazard mitigation. A high-level summary of the key plans, studies and reports is summarized in the table below. Information on how they informed the update are noted and incorporated where applicable. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-18 Table 3-5 Summary of Review of Key Plans, Studies and Reports Plan, Study, Report Name How Plan informed LHMP County of San Luis Obispo General Plan and Elements (Safety, Agricultural, Conservation and Open Space, Land Use) Provided background information on the county including some information related to jurisdictions. The elements were used to provide information on risk and vulnerabilities to hazards and the existing policies the County has in place related to hazards and mitigation. Municipal General Plans (including Safety Elements, Land Use Elements, and Housing Elements) Informed the municipal annexes and in some cases the community service district annexes on past hazard events, mitigation policies, combining designations and existing and projected development Local Hazard Mitigation Plans (City of Atascadero, City of Morro Bay, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, Los Osos CSD and the City Arroyo Grande/ City Grover Beach/Lucia Mar Unified School District/South San Luis Obispo County Sanitation District) Informed the HIRA sections, mitigation action plans and capability assessments for the applicable annexes Area Plans (Estero, Inland, North Coast, San Luis Bay Coastal, South County Coastal) Informed the community and district profiles Community Plans (Avila Beach, San Miguel, Nipomo, Los Osos) Informed the community service district profiles Urban Water Management Plans (Arroyo Grande, Atascadero) Informed the drought and water shortage sections of the applicable annexes San Luis Obispo County Flood Insurance Study Reviewed for information on past floods and flood problems to inform risk assessment (Section 4) Utilized Digital Flood Insurance Rate Maps effective January 2016 to update maps and flood risk assessment in Section 4. State of California Multi-Hazard Mitigation Plan (draft 2018) Reviewed information on climate change and hazard assessment data to ensure consistency with this plan update Reviewed list of hazards to inform risk assessment (Section 4) Reviewed goals for consistency during the update of the Fresno Multi-jurisdictional Hazard Mitigation Plan NOAA National Centers for Environmental Information- State Climate Summaries Reviewed information on climate change to inform risk assessment (Section 4) California Department of Finance/U.S. Census Bureau, American Community Survey, 2013-2017 Informed the background on the community including demographic trends 2018 Economic Profile, San Luis Obispo Chamber of Commerce Informed the economic section of the Community Profile including the top employers in the County California County Level Economic Forecast 2018 -2050, California Department of Transportation Office of State Planning Informed the development trends section of the Community Profile and how the State is forecasting the County’s growth in terms of population, economy and housing production County of San Luis Obispo EnergyWise Plan, ClimateWise Integrated Climate Change Adaptation Planning in San Luis Obispo, California’s Fourth Climate Inform climate change projections and possible effects on the County and the “climate change considerations” for each hazard profiled ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-19 Plan, Study, Report Name How Plan informed LHMP Change Assessment: Central Coastal Region Report (2018) San Luis Obispo County Integrated Regional Water Management Plan (Draft 2019) and San Luis Obispo County Stormwater Resource Plan Informed the background section on adverse weather in general. Including how the county is divided into watershed groups and annual precipitation information USDA Risk Management Agency Crop Indemnity Reports, 2015-2018 Informed the adverse weather section vulnerability assessment on how crops have been impacted by weather events in the past. Also informed the Drought and Agricultural Pests and Disease sections of the HIRA California Climate Adaptation Strategy, 2018 and California OES Contingency Plan for Excessive Heat Emergencies (2014) Informed the Extreme Heat profile and climate change considerations Dam and Levee Failure Evacuation Plan, County of San Luis Obispo Informed the Dam Failure profile and vulnerability assessment and provided information on levees of concern in the Flood profile. Also informed applicable jurisdictional annexes Land Subsidence from Groundwater Use in California (2013) James W. Borchers and Michael Carpenter, Luhdorff & Scalmanni Consulting Engineers Informed the Land Subsidence profile Tsunami Response Plan, County of San Luis Obispo Informed the Tsunami profile the base plan HIRA and applicable jurisdictional annexes Community Wildfire Protection Plan, San Luis Obispo County (March 2019) Informed the Wildfire profile in the base plan HIRA and applicable jurisdictional annexes Community Health Assessment, County of San Luis Obispo Health Agency Provided background information on the county and informed the biological agents Other technical data, reports and studies were reviewed and considered, as appropriate, during the collection of data to support Planning Steps 4 and 5, which include the hazard identification, vulnerability assessment, and capability assessment. Information from the following agencies and groups in were reviewed in the development and update of this plan. Specific references relied on in the development of this plan are also sourced throughout the document as appropriate. •California Department of Forestry and Fire Protection •California Department of Parks and Recreation Office of Historic Preservation •California Department of Transportation •California Department of Public Health •California Natural Resources Agency •California Department of Water Resources •California Geological Survey •County of San Luis Obispo Agricultural Department •County of San Luis Obispo Public Health Department •County of San Luis Obispo Information Technology Department •County of San Luis Obispo Planning and Building Department •County of San Luis Obispo Public Works Department •County of San Luis Obispo Office of Emergency Services ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-20 •California Coastal Commission •California Water Foundation •San Luis Obispo County Flood Control and Water Conservation District •National Oceanic and Atmospheric Administration National Climatic Data Center •National Register of Historic Places •Natural Resource Conservation Service •National Weather Service •U.S. Fish and Wildlife Service •U.S. Geological Survey •Western Regional Climate Center •San Luis Tribune •Center for Western Weather and Water Extremes Integration of 2014 Plan into Other Plans and Planning Mechanisms In addition, the 2014 hazard mitigation was incorporated into several County plans and planning mechanisms. The risk assessment informed the update of the County Emergency Operations Plan. Mitigation projects were proposed as part of County work plans for actual implementation related to drought and fire. On December 3, 2013, the County Board of Supervisors approved an amendment to the San Luis Obispo General Plan Safety Element by Resolution 2013-296. Through this amendment effective January 2, 2014, the Local Hazard Mitigation Plan was incorporated by reference in compliance with California Assembly Bill 2140, stating: “The San Luis Obispo County Local Hazard Mitigation Plan presents a comprehensive risk assessment of natural hazards that have the potential to affect San Luis Obispo County. The Local Hazard Mitigation Plan was developed by the County in accordance with the federal Disaster Mitigation Act of 2000, adopted by the Board of Supervisors and approved by the Federal Emergency Management Agency. The Local Hazard Mitigation Plan suggests possible mitigation measures for reducing the effects of the potential hazards. It is incorporated by this reference into the Safety Element and should be consulted when addressing known hazards to ensure the general health and safety of people within San Luis Obispo County. The goals and policies within this Safety Element support and are consistent with the recommended mitigation strategy within the Local Hazard Mitigation Plan.” The 2019 HMP update was coordinated with and done in parallel with the update of the 1999 Safety Element of the County General Plan to ensure consistency of policies. Several of the participating jurisdictions previously participated in other single or multi-jurisdictional plans, primarily the municipalities. Where those plans have been integrated into other planning mechanisms is noted in the ‘Mitigation Planning History and 2019 Process’ in the jurisdictional annexes. 3.4.2 Phase 2: Assess Risks Planning Step 4: Identify the Hazards Wood led the HMPC in an effort to review the list of hazards identified in the 2014 plan and document all the hazards that have, or could, impact the planning area, including documenting recent drought, flood, wildfire and winter storm events. Data collection worksheets were used in this effort to aid in determining hazards and vulnerabilities and where risk varies across the planning area. The profile of each of these ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-21 hazards was then updated in 2019 with information from the HMPC and additional sources. Web resources, existing reports and plans, and existing GIS layers were used to compile information about past hazard events and determine the location, previous occurrences, probability of future occurrences, and magnitude/severity of each hazard. Geographic information systems (GIS) were used to display, analyze, and quantify hazards and vulnerabilities where data permitted. The potential for climate change to affect the frequency and intensity of the hazards was summarized based on latest available science, where applicable. A more detailed description of the hazard identification and risk assessment process and the results are included in Section 5 Risk Assessment. Planning Step 5: Assess the Risks After updating the profiles of the hazards that could affect the County, the HMPC collected information to describe the likely impacts of future hazard events on the participating jurisdictions. This step included two parts: a vulnerability assessment and a capability assessment. Vulnerability Assessment—Participating jurisdictions updated their assets at risk to natural hazards— overall and in identified hazard areas. These assets included total number and value of structures; critical facilities and infrastructure; natural, historic, and cultural assets; and economic assets. The HMPC also analyzed development trends in hazard areas. The latest DFIRM was used to refine the estimate flood losses during the update, where available for the NFIP participating communities. Capability Assessment— The HMPC also conducted a capability assessment update to review and document the planning area’s current capabilities to mitigate risk and vulnerability from natural hazards. By collecting information about existing government programs, policies, regulations, ordinances, and emergency plans, the HMPC can assess those activities and measures already in place that contribute to mitigating some of the risks and vulnerabilities identified. This information for the County is included in Section 6 and in the respective jurisdictional annexes. This addressed FEMA planning task 4: Review community capabilities - 44 CFR 201.6 (b)(2) & (3). Results of the risk assessment was presented, and comments discussed at the second meeting of the HMPC in April 2019. A more detailed description of the risk assessment process and the results are included in Section 5 Risk Assessment. 3.4.3 Phase 3: Develop the Mitigation Plan Planning Step 6: Set Goals Wood facilitated a discussion session with the HMPC to review the 2014 plan’s goals and objectives. The HMPC discussed definitions and examples of goals, objectives, and actions and considered the goals of the state hazard mitigation plan and other relevant local plans when reviewing and revising the goals and objectives. The resulting updated goals and objectives are presented in Section 7 Mitigation Strategy. Planning Step 7: Review Possible Activities Wood facilitated a discussion at an HMPC meeting to review the alternatives for mitigating hazards. This included a brainstorming session with the HMPC to identify a comprehensive range of mitigation actions for each identified hazard, and a method of selecting and defending recommended mitigation actions using a series of selection criteria. More specifics on the process and the results of this collaborative process are captured in Section 7 Mitigation Strategy. ••• Section 3 Planning Process San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 3-22 As part of the review of mitigation options long term climate change adaptation strategies were also discussed. HMPC members were encouraged to incorporate climate change adaptation measures into the mitigation strategy of their respective jurisdictions utilizing resources and guidance available on the Cal-Adapt website. Planning Step 8: Draft an Action Plan Based on input from the HMPC regarding the draft risk assessment and the goals and activities identified in Planning Steps 6 and 7, Wood produced a complete first draft of the plan. This complete was shared electronically with the HMPC for review and comment. Other agencies were invited to comment on this draft as well. HMPC and agency comments were integrated into the second draft, which was advertised and distributed to collect public input and comments. Wood integrated comments and issues from the public, as appropriate, along with additional internal review comments and produced a final draft for the California Office of Emergency Services and FEMA Region IX to review and approve, contingent upon final adoption by the governing boards of each participating jurisdiction. 3.4.4 Phase 4: Implement the Plan and Monitor Progress Planning Step 9: Adopt the Plan In order to secure buy-in and officially implement the plan, the plan was adopted by the governing boards of each participating jurisdiction on the dates included in the adoption resolutions in Appendix D: Adoption Resolutions. The final plan will be included in the safety element of the County General Plan and result in the County’s eligibility for Assembly Bill (AB) 2140. This adoption makes the jurisdiction eligible for consideration for part or all of its local costs on eligible public assistance to be provided by State share funding through the California Disaster Assistance Act. Planning Step 10: Implement, Evaluate, and Revise the Plan The true worth of any mitigation plan is in the effectiveness of its implementation. Up to this point in the plan update process, all of the HMPC’s efforts have been directed at researching data, coordinating input from participating entities, and updating and developing appropriate mitigation actions. Each recommended action includes key descriptors, such as hazard(s) addressed, lead manager and priority, to help initiate implementation. An overall implementation strategy is described in Section 8 Plan Implementation and Monitoring. Finally, there are numerous organizations within the San Luis Obispo County planning area whose goals and interests’ interface with hazard mitigation. Coordination with these other planning efforts, as addressed in Planning Step 3, is paramount to the ongoing success of this plan and of mitigation in San Luis Obispo County and is addressed further in Section 8. A plan update and maintenance schedule and a strategy for continued public involvement are also included in Section 8. Implementation and Maintenance Process: 2014 Plan The 2014 LHMP included a process for implementation and maintenance which was generally followed, with some variation. Implementation of the plan including the status of mitigation actions is captured in Section 7 and the jurisdictional annexes. In general, the County and participating jurisdictions have made progress in the implementation of the plan. Successes of note are detailed in Section 7. An updated implementation and maintenance section can be referenced in Section 8. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-1 SECTION 4 SAN LUIS OBISPO COUNTY PROFILE 4.1 County History The area that today comprises San Luis Obispo County was home to the Chumash people thousands of years before the present age. Important settlements existed in many coastal areas such as Morro Bay and Los Osos. Mission San Luis Obispo de Tolosa was founded on September 1, 1772 in the area that is now the City of San Luis Obispo. The namesake of the mission, city and county is Saint Louis of Toulouse, the young bishop of Toulouse (Obispo and Tolosa in Spanish) in 1297. San Luis Obispo County, the 16th largest County in California, is one of the original 27 California counties created by Act of the State Legislature on February 18, 1850. 4.2 Geography Located along California’s Central Coast, San Luis Obispo County is midway (190 miles/306 kilometers) between Los Angeles and San Francisco and is accessible north-to-south by U.S. Highway 101 and scenic Highway 1. Routes from the east include State Highways 41, 46, 58 and 166. San Luis Obispo County is bordered by Santa Barbara County to the south, Monterey County to the north and Kern County to the east. Kings County shares a small border with San Luis Obispo County at the north east corner of the County. The County encompasses 3,316 square miles or 2,114,750 acres and stretches along 80 miles of coastline. The highest point is Caliente Mountain (5,104 feet). The lowest point is sea level. A series of ancient volcanic peaks, referred to as the “nine sisters”, lie between Morro Bay and San Luis Obispo. Most notable of the peaks is Morro Rock, often called the sentinel of the Pacific Ocean. The Central Coast of California is susceptible to a number of natural hazards. This HMP profiles the most significant of these hazards. Historical data, catastrophic potential, relevance to the jurisdiction, and the probability and potential magnitude of future occurrences were all used to reduce and prioritize the list of hazards to those most relevant to San Luis Obispo County. The following map shows the geography of the County. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-2 Figure 4-1 San Luis Obispo County PACIFIC OCEAN Waterways Lakes ---+--+ Railroads Highway Free way Bureau of Land Management -US Forest Serv ice ••• Map comp iled 2/2019 ; intended for planning purposes on ly. Data Source : San Lu is Obispo County, US Census TIGER Database , CA Open Data Portal , SLM /California State Office 0 Monterey I \ 10 20 Santa Barbara I I I Kings i Tulare I I I ---··------------------------ Kern -, '-=-----L_ Ventura 40 Miles N A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-3 4.3 Cities and Communities The incorporated cities within San Luis Obispo County are: •Arroyo Grande •Atascadero •Grover Beach •Morro Bay •Paso Robles •Pismo Beach •San Luis Obispo Unincorporated communities and Census Designated Places (CDP) include: •Avila Beach •Blacklake •Callender •California Valley •Cambria •Cayucos •Cholame •Creston •Edna •Garden Farms •Halcyon •Harmony •Lake Nacimiento •Los Berros •Los Osos-Baywood Park •Los Ranchos •Nipomo •Oak Shores •Oceano •Pozo •San Miguel •San Simeon •Santa Margarita •Shandon •Templeton •Whitley Gardens •Woodlands In addition to traditionally noted cities and communities, areas such as the Camp Roberts military installation, Camp San Luis, and California Polytechnic State University-San Luis Obispo can be considered communities in and of themselves. San Luis Obispo County works and interacts with these institutions in many ways similar to how the County interacts with other communities outside the scope of this plan. However, it is recognized these listed entities fall under the authority and jurisdiction of the State of California and/or the U.S. Government. Additionally, the County contains several Community Services Districts (CSDs) or other special districts. California state law allows residents of an unincorporated area to initiate the formation of a community services district to provide any of a wide variety of services, including water, garbage collection, wastewater management, security, fire protection, public recreation, street lighting, mosquito abatement, conversion of overhead utilities to underground, library services, ambulance services, and graffiti abatement. A CSD may span unincorporated areas, multiple cities and/or counties. Once a CSD is formed, the residents elect a board to oversee CSD management and operations. Following is a list of all CSDs and special districts in San Luis Obispo County. Districts that are participating jurisdictions in this plan update process are bolded. Figure 4-2 shows the CSDs and special districts that participated in the 2019 planning process. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-4 •Arroyo Grande Cemetery District •Atascadero Cemetery District •Atascadero Public Financing Authority •Atascadero Unified School District Educational Facilities Corporation •Avila Beach CSD •California Valley CSD •Cambria Cemetery District •Cambria Community Healthcare District •Cambria CSD •Cayucos Fire Protection District •Cayucos Sanitary District •Cayucos-Morro Bay Cemetery District •Central California Schools Financing Authority •Central Coast Cities Joint Powers Self - Insurance Fund - Compensation •Central Coast Cities Joint Powers Self- Insurance Fund-Liability •City of Arroyo Grande Public Financing Authority •City of Pismo Beach Public Facilities Corporation •Coastal San Luis Resource Conservation District •County Service Area No. 1 •County Service Area No. 7 •County Service Area No. 9 •County Service Area No. 10 •County Service Area No. 12 •County Service Area No. 16 •County Service Area No. 17 •County Service Area No. 18 •County Service Area No. 21 •County Service Area No. 22 •County Service Area No. 23 •Creston Hills Ranch CSD •El Paso de Robles Public Financing Authority •Five Cities Fire Authority •Garden Farms Community Water District •Ground Squirrel Hollow CSD •Heritage Ranch CSD •Independence Ranch CSD •Linne CSD •Los Osos CSD •Nipomo CSD •Nipomo Lighting District •Oceano CSD •Paso Robles Cemetery District •Paso Robles Joint Unified School District Educational Facilities Corporation •Pismo Beach Public Financing Authority •Port San Luis Harbor District •San Luis Obispo County Air Pollution District •San Luis Obispo County Financing Authority •San Luis Obispo County Flood Control and Water Conservation District •San Luis Obispo County Integrated Waste Management Authority •San Luis Obispo Public Financing Authority •San Miguel Cemetery District •San Miguel CSD •San Simeon CSD •Santa Margarita Cemetery District •Santa Margarita Fire Protection •Schools Insurance Program for Employees •Shandon Cemetery District •South San Luis Obispo County Sanitation District •Squire Canyon CSD •Templeton Cemetery District •Templeton CSD •Templeton Unified School District Educational Facilities Corporation •Upper Salinas/Las Tablas Resource Conservation District ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-5 Figure 4-2 Participating Districts MONTER EY PASO R OBLES PACIFIC OCEAN --+---Railroads Highway Freeway 1:::::: :J Cities Community Service District -Avila Beach LJ Ground Squirrel Hollow -HerHage Ranch -LosOsos -Nipomo -Oceana San Miguel San Simeon LJ Templeton Map comp il ed 5120 19; ••• intended for p lanning purposes only. Data Source : San Luis Obispo County, us Census T IGER Da tabase , CA Open Data Portal , LAFCO Special Distric1s Cayu cos Sanitation District ~ South SLO County Sanitation District : Port San Luis Harbor Dist rict 1D 2D Mi les KI N G S SANTA MO NICA N A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-6 4.4 Population and Demographics Profile This section was updated in 2019 using data from the 2012-2017 American Community Survey (ACS) 5- Year Estimates. Population The U.S. Census Bureau estimated San Luis Obispo County’s total population of 280,119 as of 2017. This constitutes a 4% increase in population from the 2014 plan (269,637 persons). The tables below list the total population estimates for each jurisdiction, and shows how they have changed in the last five years. Table 4-1 San Luis Obispo County Population Change, 2012-2017 Jurisdiction 2012 2013 2014 2015 2016 2017 % Change 2012-2017 San Luis Obispo County 270,121 272,094 274,184 276,517 278,680 280,119 +4% Arroyo Grande City 17,284 17,411 17,536 17,720 17,842 17,971 +4% Atascadero City 28,441 28,613 28,792 29,084 29,516 29,797 +5% Avila Beach CDP* NA NA 1,166 1,270 1,242 1,080 -7% Cayucos CDP 2,431 2,475 2,553 2,758 2,987 2,847 +17% Grover Beach City 13,194 13,253 13,337 13,409 13,484 13,524 +3% Los Osos CDP 14,874 14,177 14,778 15,388 15,603 15,714 +6% Nipomo CDP 16,747 17,256 17,115 16,727 16,456 16,706 +0% Oceano CDP 7,543 7,453 7,355 7,857 8,262 7,788 +3% Paso Robles City 29,770 30,144 30,522 30,863 31,178 31,409 +6% Pismo Beach City 7,721 7,746 7,789 7,890 7,984 8,060 +4% San Luis Obispo City 45,328 45,584 45,911 46,337 46,716 46,997 +4% San Miguel CDP 2,822 2,621 2,638 2,461 2,696 2,824 +0% San Simeon CDP 513 534 477 284 325 523 +2% Templeton CDP 7,200 7,525 7,753 7,377 7,525 7,989 +11% Source: U.S. Census Bureau American Community Survey, www.census.gov/. Avila Beach data not available prior to 2014. Note: Data for Census Designated Places (CDP) may not have the same boundaries as the participating Community Service Districts. Table 4-2 and Table 4-3 show several key demographic and social characteristics of San Luis Obispo County, how those characteristics have changed over the last five year, and how those characteristics compare to the rest of the state and nation. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-7 Table 4-2 San Luis Obispo County Demographic and Social Characteristics, 2012-2017 San Luis Obispo County 2012 2017 % Change Population 270,121 280,119 3.7% Median Age 39.3 39.0 -0.8% Total Housing Units 117,318 120,182 2.4% Housing Occupancy Rate 86.7% 87.4% 0.7% % of Housing Units with no Vehicles Available 4.5% 4.5% 0.0% Median Home Value $449,300 $499,800 11.2% Unemployment 8.7% 4.8% -3.9% Mean Travel Time to Work (minutes) 20.9 21.8 4.3% Median Household Income $59,628 $67,175 12.7% Per Capita Income $30,218 $33,972 12.4% % of Individuals Below Poverty Level 13.7% 13.8% 0.1% # of Households 101,708 105,044 3.3% Average Household Size 2.49 2.51 0.8% % of Population Over 25 with High School Diploma 89.5% 90.5% 1.0% % of Population Over 25 with Bachelor’s Degree or Higher 31.5% 34.0% 2.5% % with Disability 11.1% 11.1% 0.0% % Speak English less than "Very Well" 6.7% 6.8% 0.1% Source: U.S. Census Bureau American Community Survey www.census.gov/ Table 4-3 Demographic and Social Characteristics Compared to the State and Nation Demographic & Social Characteristics (as of 2017) County California U.S. Median Age 39.0 36.1 37.8 Housing Occupancy Rate 87.4% 92.1% 87.8% % of Housing Units with no Vehicles Available 4.5% 7.4% 8.8% Median Home Value $499,800 $443,400 $193,500 Unemployment 4.8% 7.7% 6.6% Mean Travel Time to Work (minutes) 21.8 28.8 26.4 Median Household Income $67,175 $67,169 $57,652 Per Capita Income $33,972 $33,128 $31,177 % of Individuals Below Poverty Level 13.8% 15.1% 14.6% Average Household Size 2.51 2.96 2.63 % of Population Over 25 with High School Diploma 90.5% 82.5% 87.3% % of Population Over 25 with bachelor’s degree or Higher 34.0% 32.6% 30.9% % with Disability 11.1% 10.6% 12.6% % Speak English less than "Very Well" 6.8% 18.4% 8.5% Source: U.S. Census Bureau American Community Survey www.census.gov/ Table 4-4 and Figure 4-3 breakdown the demographics of the county by sex, race, and age. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-8 Table 4-4 Demographics by Race and Sex San Luis Obispo County Population % Total Population 280,119 --- Male 142,182 50.8% Female 137,937 49.2% Hispanic or Latino 62,174 22.2% White alone 194,355 69.4% Black alone 4,958 18.0% Asian alone 9,998 3.6% American Indian and Alaska Native alone 1,237 0.4% Native Hawaiian and Other Pacific Islander alone 280 0.1% Some other race alone 109 0.0% Two or more races alone 7,008 2.5% Source: U.S. Census Bureau American Community Survey www.census.gov/ Figure 4-3 San Luis Obispo County Population By Age Housing Characteristics The 2010 United States Census documented 117,315 housing units, 13 percent of which were vacant. The table below presents the 2017 American Community Survey estimates for types of housing units. - 10,000 20,000 30,000 40,000 ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-9 Table 4-5 Types and Total Amounts of Housing Units in San Luis Obispo County Type of housing units Total Percentage 1-unit detached 80,791 67% 1-unit attached 6,527 5.4% 2 units 3,878 3.2% 3 or 4 units 6,190 5.2% 5 to 9 units 5,035 4.2% 10 to 19 units 3,117 2.6% 20 or more units 4,180 3.5% Mobile home 10,185 8.5% Boat, RV, van, etc. 279 0.2% Total housing units 120,182 100% Source: U.S. Census Bureau American Community Survey www.census.gov/ Occupied Housing Unit Characteristics: According to the 2017 American Community Survey, San Luis Obispo had 120,182 total housing units, of which 105,044 (87.4% were occupied. 60 percent of the occupied housing units were owner-occupied and 40% renter-occupied. More than half the total housing units (52.4%) were built in 1980 or later. However nearly half of residents (45.3%) had been in their current housing for eight years or less. Only 4.5% of occupied housing units have no vehicles available for private use, considerably below state and national averages (7.4% and 8.8% respectively). 67.6% of occupied housing units use utility gas for heating, with another 17.9% using electric heating. Housing Costs: The median value of owner-occupied housing units in 2017 was $499,800; this represents an 11.2% increase since 2012, and is 12.7% above the average in California. More than 70% of owner- occupied units were valued between $300,000 and $999,999. Eight percent were valued at $1,000,000 or more. Most owner-occupied units had a mortgage (67.5%). The median rent cost during this time was $1,326, and 45.9% of renters were paying 35% or more of their income for housing. Households and Families: In 2017 the average household size was 2.51 persons. There were 105,044 total households, 66,465 (63.3%) of which were family households (62.4%). Income and Employment: The median household income in 2017 was $67,175, a 12.7% increase over 2010; this is statistically the same as the statewide average ($67,169). Per capita income increased similarly during this period, from $30,218 in 2012 to $33,972 in 2017. There were 137,680 people in the labor force, with an unemployment rate of 4.8%, down from 8.7% in 2012. Figure 4-4 shows the number of people earning different income levels in the County as of 2017. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-10 Figure 4-4 Income Distribution in San Luis Obispo County Source: U.S. Census Bureau American Community Survey www.census.gov/ Poverty: In 2017, 13.8% of county residents lived in poverty. 12.9% of related children under 18 were below the poverty level, compared with 6% of people 65 years old and over. 6.6% of all families had incomes below the poverty level, although that number increases to 20.5% for families with a female householder and no husband present. Language: Among people at least five years old living in San Luis Obispo County in 2017, 81.8% spoke primarily English at home. Spanish was spoken in 14% of homes. A total of 6.8% households reported they spoke English less than “very well”, which is well below the statewide and national averages (18.4% and 8.5% respectively). Since the 2010 census there has been a slight decrease (1.5%) in English as the primary language spoken at home, in the same time period the percentage of individuals who speak Spanish at home and households that reported to speak English less than “very well” increased by 0.9%. Education: In 2017, 90.5% of people 25 years and over had at least graduated from high school and 34 percent had a bachelor's degree or higher. The total school enrollment in San Luis Obispo County was 77,327 for persons 3 years and over. Nursery school and kindergarten enrollment was 6,484 and elementary or high school enrollment was 33,824 children. College or graduate school enrollment was 37,019. People with Disabilities: 30,019 persons (11.1%) were living with some form of disability in 2017. This in unchanged from 2012 and is close to statewide and national averages (10.6% and 12.6% respectively). Health Insurance Coverage: As of 2017, 91.4% of residents had health insurance coverage, including 73.4% with private insurance (alone or with public coverage) and 32.8% with public coverage alone or with private coverage. 4.4.1 Social Vulnerability Social vulnerability considerations were included in the update of this plan in 2019 to identify areas across the County that might be more vulnerable to hazard impacts based on a number of factors. A social vulnerability index (SoVI) was developed by the Center for Disease Control’s (CDC) Agency for Toxic 0 5,000 10,000 15,000 20,000 ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-11 Substances and Disease Registry (ATSDR) and their Geospatial Research, Analysis & Services Program teams, as a way to portray communities’ capacities to prepare for and respond to natural and man-made disasters. The SoVI does so by providing insight into particularly vulnerable populations to in turn assist emergency response planners and even public health officials identify communities more likely to require additional support before, during, and after a hazardous event. The CDC’s SoVI create county- and state- level maps to show relative vulnerability and hence provide key socially and spatially relevant information on communities’ populations, and these maps compare the SoVI based on Census Tracts. The overall social vulnerability based on the SoVI data is shown for the County of San Luis Obispo by Census Tracts in Figure 4-5 below, based on statewide ranking. This overall index combines four main themes of vulnerability, namely: socioeconomic status; household composition and disability; minority status and language; and housing and transportation, which in turn are comprised of subcategories for a total of 15 variables accounting for various vulnerability factors. For additional information on the CDC’s SoVI, refer to their documentation and materials online at https://svi.cdc.gov/. Based on this data, the areas with the highest level of social vulnerability in the county are Grover Beach, Oceano, southwestern San Luis Obispo City, southeastern Atascadero, southeastern and western Paso Robles, San Miguel, and the Adelaida region. ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-12 Figure 4-5 Overall Social Vulnerability in San Luis Obispo based on the SoVI, by Census Tracts CDC's Social Vulnerability Index 2016 San Luis Obispo County, California Overall Social Vulnerability1 ii Hi· Highest (Top 4th) Vulnerability (SVI 2016)2 uis po SAN L U I S ISP 0 Lowest (Bottom 4th) 0 B 0 Data Unavailabl e 3 0 4.25 8 .5 17 25.5 Miles 1 7 ~::::i~µ:;:::c==+tF===, Social vulnerability refers to a community's capacity to prepare for and respond t o the st ress o f hazardous events ranging from natural disasters, suc h as tornadoes or disease outbreaks, to human- ca used threats, such as toxic chemical spills . The Social Vulnerability Index (SVI 2016 )4 County M a p depicts the social vulnerability of communiti es, a t census tract level, within a specified count y. SVI 2016 groups fiftee n censu s-derived factors into four t he m es that summarize the extent to which t he area is socially vulnerable to disaster. The factors include economic data as well as data regarding education, family characteristics, housing, language ability, e thnicity, and vehicle access . Overall Social Vulnerability combines all t he variables to provide a comprehensive assessment . CA ~ UT '-----------=-- A en for Toxic Substances and Disease Re ist E~II FINAL -FOR EXTERNAL USE ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-13 San Luis Obispo County Planning & Building staff also applied the CDC methodology to refine Census Tract level summaries into finer scale aggregation units associated with Census Designated Places (CDP), to provide social vulnerability perspectives on more tangible community centers. The results of this CDP based analysis further informs the vulnerability of people as discussed for each hazard in Section 5; the SoVI data was further used to inform the County’s General Plan Safety Element update in 2019. The overall social vulnerability of the County by CDP is portrayed in Figure 4-6. Additional maps using the CDPs and the four main vulnerability themes of the SoVI are shown in Figure 4-7 (socioeconomic vulnerability theme), Figure 4-8 (household composition and disability vulnerability theme), Figure 4-9 (minority status and language vulnerability theme), and Figure 4-10 (housing and transportation vulnerability theme). For additional information on the CDC’s SoVI, refer to their documentation and materials online at https://svi.cdc.gov/. . ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-14 Figure 4-6 Overall Social Vulnerability in San Luis Obispo based on the SoVI, by Census Designated Place PACIFIC OCEAN CDC's Social Vulnerability Index by Census Designated Place Lowesl (Bottom 4th) -;--Railroads Low-Medium --Freeway -Me~lum·High --Hist,way -Hg hest (Top 4t h) c=J Counties 'W. loe,pan:me-nt of ....._ Plannlng&Bulldlng ••• Map compiled 11/2019; intended for planning purposes on ty. Data Source: San Luis Obispo County, US Census TIGER Database, CA Open Data Portal, CDC SVI 2016 Grover Beach 0 Kings Tulare r~- ,1 Ventura I N 10 20 40 Miles A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-15 Figure 4-7 Socioeconomic Vulnerability in San Luis Obispo by Census Designated Place PACIFIC OCEAN Socioeconomic Vulnerability by Census Designated Place La wesl (Boltom 41h) ~ Ra ilroads -Low-Me di um -Medium-High -t-tgnest (Top 4tnJ 'W... I Depar-tm~nt of ~ Phmnlng& Du il di n.g ••• --Fr eeway --Highway Counties Map compiled 11/201 9; intended for panni ng purpose, only. Data Source: San Lu is. Obispo County, US Census TIGER Database, CA Open Data Portal, CDC SVI 2016 0 I I f Tulare i ___ ,. __ _ Kern ..A N 10 20 40 Mi les A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-16 Figure 4-8 Household Composition and Disability Vulnerability in San Luis Obispo by Census Designated Place PACIFIC OCEAN Household Composition & Disability Vulnerability by Census Designated Place LOW1!sl (Bottom 4th) -+--Roilroods -L~Medium --Freeway -Medium-High --Hig'May -Hghest (Top 4th) Counties "W... IDtpartment or ""'Plann lng&8uildlng ••• Map comp led 11/2019; intended for plann ing purposes only. Data Source: San Luis Obispo County, US Census T IGER Database, CA Open Dala Portal, CDC SVI 2016 Grover Beach 0 10 20 40 Miles Tulare I Ventura I N A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-17 Figure 4-9 Minority and Language Vulnerability in San Luis Obispo by Census Designated Place PACIFIC OCEAN Minority and Language Based Vulnerability by Census Designated Place Lowo,1 (Bo llom 41h) -;--Railroads -Low-Medium -Medium-High -Hghe51 (To p 4th) 'W._ loepartme-nt of ~ Planning& OUlldln.g ••• --Freeway --Hi!1,way Counties Map compi led 11/2019; in tended for planning purposes only. Data Source : San Luis Ob ispo County, US Ce nsus TIGER Database, CA Open Data Ponal, CDC SVI 2016 Kings Tulare Ventura N 0 10 20 40 Miles A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-18 Figure 4-10 Housing and Transportation Vulnerability in San Luis Obispo by Census Designated Place PACIFIC OCEAN Housing & Transportation Vulnerability by Census Designated Place Lowo,I (Bollom 41h) -Low-Mea1um --Ra ilro ads -Medium-High --Freeway -Hghest (Top 4th) --Highway D No Data Availab le Counties .... I Department of ~ Plan ning & Bui ld Ing ••• Map compiled 11/2019; intended for plann ing purposes on ly. Data Source: San Luis Ob ispo County. US Census TIGER Dat ab ase, CA Open Data Portal, CDC SVI 2016 GroverBe·ach 0 Kings Tu lare --, L _ I j Ventura I N 10 20 40 Miles A Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-19 Environmental Justice Considerations SB 1000 Requirements §65302(h)(1) The environmental justice element, or related environmental justice goals, policies, and objectives integrated in other elements, shall do all of the following: (A)Identify objectives and policies to reduce the unique or compounded health risks in disadvantaged communities by means that include, but are not limited to, the reduction of pollution exposure, including the improvement of air quality, and the promotion of public facilities, food access, safe and sanitary homes, and physical activity. (B)Identify objectives and policies to promote civil engagement in the public decision-making process. (C)Identify objectives and policies that prioritize improvements and programs that address the needs of disadvantaged communities. In 2016 California passed Senate Bill 1000 (SB 1000), the Planning for Healthy Communities Act, requiring cities and counties with disadvantaged communities to include environmental justice (EJ) in their General Plans when they are updating two or more elements of their General Plan concurrently on or after January 1, 2018. Environmental justice is defined by state law as “the fair treatment of people of all races, cultures, and incomes with respect to the development, adoption, implementation, and enforcement of environmental laws, regulations, and policies” (Gov. Code § 65040.12e). SB 1000 defines disadvantaged environmental justice (EJ) communities as those that either 1) rank in the top 25th percentile of the CalEnviroScreen Index, or 2) are low-income and disproportionately affected by exposure to environmental pollution and other hazards that can lead to negative health effects or environmental degradation. This two-part definition creates a "black and white" baseline and another that allows a city or county to cater to its communities through its broad language. Per the first definition, no areas in San Luis Obispo County contain disadvantaged communities. Per the second definition, local jurisdictions may subjectively interpret how to identify disadvantaged communities based on a regional analysis. This LHMP addresses these considerations to a degree in the social vulnerability assessment for each hazard in Section 5 and prioritization criteria for mitigation actions in Section 7. Prioritization criterial includes a ‘Social’ element which considers applying a higher priority to actions that relate to social equity, benefits disadvantaged communities, or addresses vulnerable populations. In addition, the County of San Luis Obispo adopted Mitigation Action C.1.3 to increase involvement of disadvantaged communities in disaster preparedness activities and prioritize programs that address their needs and incorporated these requirements into the Safety Element of the General Plan during a process parallel to this LHMP update. Other cities and counties may choose to identify disadvantaged communities within their jurisdictions and incorporate the SB 1000 requirements into their planning processes. 4.5 Economy Table 4-6 breaks down San Luis Obispo County’s labor force by industry as of 2017. The largest sector of employment is in educational services, health care, & social assistance, which makes up 22.2% of jobs in the County. They’re followed by the arts, entertainment, recreation, accommodation, & food services sector (11.8%), retail trade (10.8%), and the professional, scientific, and management, and administrative and waste management services sector (10.0%). ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-20 Table 4-6 San Luis Obispo County Employment by Industry (2017) Industry # Employed Population (2017) 280,119 In Labor Force 137,680 Agriculture, forestry, fishing and hunting, and mining 4,480 Armed Forces 1,817 Construction 10,235 Manufacturing 8,841 Wholesale trade 2,820 Retail trade 14,851 Transportation and warehousing, and utilities 5,845 Information 2,012 Finance and insurance, and real estate and rental and leasing 5,842 Professional, scientific, and management, and administrative and waste management services 13,821 Educational services, and health care and social assistance 30,501 Arts, entertainment, and recreation, and accommodation and food services 16,229 Other services, except public administration 6,676 Public administration 7,124 Unemployed 6,586 Source: U.S. Census Bureau American Community Survey 2012-2017 5-Year Estimates, www.census.gov/ The San Luis Obispo Chamber of Commerce published a 2018 Community Economic Profile for the City of San Luis Obispo with additional information about San Luis Obispo County. This section was updated in 2013 to reflect the latest data from the San Luis Obispo Chamber of Commerce. Employers: The table below reflects the top 25 employers in San Luis Obispo County as reported by the California Employment Development Department. Table 4-7 Top 25 Employers – San Luis Obispo County Company/Organization Location Industry Approximate Employees Employer Name Location Industry Employees Atascadero State Hospital Atascadero Hospitals 1,000-4,999 Cal Poly State University San Luis Obispo Schools-Universities & Colleges Academic 1,000-4,999 Glenair Inc Paso Robles Communications Consultants 1,000-4,999 Pacific Gas & Electric Co San Luis Obispo Electric Companies 1,000-4,999 San Luis Obispo County EMS San Luis Obispo Government Offices-County 1,000-4,999 AMI Sierra Vista Radiology San Luis Obispo Physicians & Surgeons 500-999 California Mid-State Fair Paso Robles Concert Venues 500-999 Cuesta College Paso Robles Junior-Community College-Tech Institutes 500-999 Division of Juvenile Justice Paso Robles State Govt-Correctional Institutions 500-999 Medi-Cal Eligibility Info San Luis Obispo Government Offices-County 500-999 ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-21 Company/Organization Location Industry Approximate Employees Mental Marketing Atascadero Advertising-Agencies & Counselors 500-999 Sierra Vista Regional Med Ctr San Luis Obispo Hospitals 500-999 Trust Rcm San Luis Obispo Billing Service 500-999 Arroyo Grande Community Hosp Arroyo Grande Hospitals 250-499 Child Abuse-Neglect-Child San Luis Obispo Business Management Consultants 250-499 County Office of Education San Luis Obispo Schools 250-499 French Hospital Medical Ctr San Luis Obispo Hospitals 250-499 Hearst Castle San Simeon National Monuments 250-499 Madonna Inn Resort San Luis Obispo Resorts 250-499 Morro Bay Art Assn Gallery Morro Bay Art Galleries & Dealers 250-499 Ramirez Farm Labor Shandon Labor Contractors 250-499 San Luis Obispo County Social San Luis Obispo Government Offices-County 250-499 San Luis Obispo Sheriff's Dept San Luis Obispo Sheriff 250-499 Social Services Dept San Luis Obispo Government Offices-County 250-499 Source: California Employment Development Department Agriculture: The agriculture industry in San Luis Obispo is a crucial part of the local economy, providing employment and income directly for those in agriculture, as well as driving growth in the tourism industry. Total crop values in 2017 were $925 million. The top 20 leading agriculture crops are listed in Table 5-3 in the Risk Assessment section. 4.6 Climate The climate and air quality of San Luis Obispo County are directly related to its physical characteristics. The coastal lowlands and plains are bounded on the east by the Santa Lucia Mountains and experience a maritime climate. That climate is somewhat modified locally by elevation and distance from the ocean, as well as the mountains. The north and northeastern portions of the County include the upper end of the Salinas Valley, where the maritime climate is substantially modified by the intervening mountains. The Carrizo Plain in the east and southeastern portion of the County is climatically high desert. Because the County is located along the California coast, the weather is normally under the influence of a high-pressure system located to the west. As a result, a common weather pattern includes afternoon and evening onshore winds. San Luis Obispo County has a pleasant, Mediterranean climate year-round, averaging 315 days of sunshine per year. •Winter: 64°F / 31°F - Cool and Sunny •Spring: 75°F / 44°F - Breezy and Cool •Summer: 94°F / 54°F - Warm Coastal Mornings/Sunny Days •Fall: 77°F / 43°F -Warm Days and Cool Nights ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-22 The 2010 & 2011 Annual Air Quality Report issued by the San Luis Obispo Air Pollution Control District notes that the County overall had good air quality. However ozone levels exceeding both federal and state standards were measured on numerous days in the rural eastern portion of the county due to transported pollution. Smoke from wildfires can often adversely affect air quality. South County air quality was impacted by dust blown from the dune complex along the coast of the Five Cities area. Only one exceedance of the federal PM10 standard occurred in 2010, but numerous exceedances of the state standard were recorded during this time frame. The County attained both federal and state standards for fine particulate matter, carbon monoxide, nitrogen dioxide, sulfur dioxide, hydrogen sulfide, and visibility. An overview of the effects of climate change on San Luis Obispo County can be found in subsection 5.1.3. 4.7 Transportation Systems The County contains major transportation arteries including U.S. Highway 101, California State Highways 1, 41, 46, 58, and 166, and the Union Pacific Railroad. The County has a regional airport near the southern portion of the City of San Luis Obispo which offers service to larger commercial airports to the north and south (Los Angeles and San Francisco, as well as flights to Phoenix). In addition to air transportation, the County is also served with scheduled rail service by Amtrak, and motor bus service by companies such as Greyhound and Orange Belt Stages, as well as a number of tour coach operators, and local transit systems. 4.8 Governing Body The Board of Supervisors serves as the Legislative body of the County of San Luis Obispo for the planning and provision of services related to public needs and the requirements of State and Federal laws. California law provides for five Supervisors to be elected by district. Each Supervisor is elected for a four- year term. Two of the Supervisors' terms are staggered so that all Supervisors are not standing for election at the same time. As the elected representative of the people of San Luis Obispo County, the Board of Supervisors establishes overall County priorities and sets policy. The San Luis Obispo County Flood Control and Water Conservation District is operated by the County Water Resources Division of Public Works. The District (Public Works Department) is the designated County agency responsible for managing, planning, and maintaining drainage and flood control facilities in the unincorporated public areas where no other agency has assumed an active role in such activities. The District has a regional role in the County and can work with individual cities or communities when requested. The County Board of Supervisors also serves as the governing body for the Flood Control District. 4.9 Land Use Existing land use within San Luis Obispo County is varied with respect to types of uses, ownership, character, and intensity. Land uses include: •Rural residential •Single family detached •Single family attached •High-density residential (apartments) •Mobile homes •Recreational open space •Other open space •Heavy industrial •Warehouse •Vacant ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-23 •Agriculture •Water •Utilities •Public facilities •Schools •Retail / Office •Tourist / Commercial recreation •Light industrial / Business park •Mineral extraction 4.10 Development Trends While the population of San Luis Obispo County is expected to continue growing, there are Land Use policies and elements within the County General Plan to help assure orderly development. The California Department of Transportation’s Office of State Planning prepared the California County- Level Economic Forecast 2018-2050. Highlights of the forecast for San Luis Obispo County include: •From 2018 to 2023, employment growth is expected to average 0.9 percent per year. •The largest employment gains will be observed in education and healthcare, leisure services, and government. Together, these sectors will account for 61 percent of net job creation during the 2018- 2023 period. •Average salaries are currently below the California average, and will remain so over the foreseeable future. In San Luis Obispo County, inflation-adjusted salaries are expected to rise by an average of 1.8 percent per year between 2018 and 2023, which will be similar to statewide growth. •Over the forecast period, an average of 970 homes will be authorized per year. Because San Luis Obispo County has large amounts of buildable land, housing production will spread out into single- family communities, rather than be forced up into multifamily skyscrapers. •The population is expected to increase by 0.4 percent annually through 2023. Net migration will account for almost all population growth. Because the County has an old population base, the number of deaths will be approximately equal to the number of births during the forecast period. Table 4-8 San Luis Obispo County Economic Forecast, 2017-2050 San Luis Obispo County 2018 2050 Population (people) 279,967 298,795 Net Migration (people) 1,326 710 Registered Vehicles (thousands) 315 355 Households (thousands) 105.7 124.9 New Homes Permitted (homes) 1,111 303 Total Taxable Sales (billions) $5.36 $19.35 Personal Income (billions) $16.14 $54.75 Real Per Capita Income (dollars) $56,044 $85,431 Inflation Rate (% change in CPI) 2.7 1.9 Real Farm Crop Value (millions) 967.2 1234.3 Real Industrial Production (millions) 2,493 4,698 Unemployment Rate (percent) 3.3 3.8 Employment (thousands of jobs) Total Wage & Salary 123.8 144.5 Farm 5.2 6.4 ••• Section 4 San Luis Obispo County Profile San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 4-24 San Luis Obispo County 2018 2050 Construction 7.7 5.5 Manufacturing 7.3 7.9 Transportation & Utilities 4.1 3.9 Wholesale & Retail Trade 17.5 22.3 Financial Activities 4.2 4.4 Professional Services 10.7 13.4 Information 1.4 1.4 Health & Education 15.7 19.7 Leisure 19.3 23.5 Government 24.8 29.5 Source: California County-Level Economic Forecast 2018-2050, California Department of Transportation Analysis of development trends in the County can be found in subsection 5.2, to include analysis of building permits. Additional discussion on development trends can be found in the Future Development section of each hazard profile in the Section 5. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-1 SECTION 5 RISK ASSESSMENT Risk, for the purposes of this plan and as defined by FEMA, is a combination of hazard, vulnerability, and exposure. “It is the impact that a hazard would have on people, services, facilities, and structures in a community and refers to the likelihood of a hazard event resulting in an adverse condition that causes injury or damage.” The risk assessment process identifies and profiles relevant hazards and assesses the exposure of lives, property, and infrastructure to these hazards. The process allows for a better understanding of a jurisdiction’s potential risk to hazards and provides a framework for developing and prioritizing mitigation actions to reduce risk from future hazard events. This risk assessment builds upon the methodology described in the 2013 FEMA Local Mitigation Planning Handbook, which recommends a four-step process for conducting a risk assessment: 1.Describe Hazards 2.Identify Community Assets 3.Analyze Risks 4.Summarize Vulnerability In essence, the risk assessment evaluates potential loss from hazards by assessing the vulnerability of the county’s population, build environment, critical facilities, and other assets. Data collected through this process has been incorporated into the following sections of this section: Subsection 5.1: Hazard Identification - identifies the hazards that threaten the Planning Area and describes why some hazards have been omitted from further consideration. Subsection 5.2: Asset Summary - describes the methodology for inventorying assets as the basis for determining vulnerability of the planning area to the identified hazards. Subsection 5.3: Hazard Analysis and Risk Assessment - discusses the threat to the Planning Area and describes previous occurrences of hazard events and the likelihood of future occurrences (2013 FEMA Local Mitigation Planning Handbook Risk Assessment Step 1). It also includes a vulnerability assessment considering assets at risk, critical facilities, and future development trends (2013 FEMA Local Mitigation Planning Handbook Risk Assessment Steps 2, 3 and 4). This risk assessment covers the entire geographical area of San Luis Obispo County. Since this plan is a multi-jurisdictional plan, the HMPC was required to evaluate how the hazards and risks vary from jurisdiction to jurisdiction. While these differences are noted in this section, they are expanded upon in the annexes of the participating jurisdictions. If no additional data is provided in an annex, it should be assumed that the risk and potential impacts to the affected jurisdiction are similar to those described here for the entire San Luis Obispo County planning area. DMA Requirement §201.6(c)(2): [The plan shall include] A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-2 5.1 Hazard Identification and Prioritization The first step in developing a risk assessment is identifying the hazards. The San Luis Obispo County HMPC conducted a hazard identification study to determine the hazards that threaten the planning area. 5.1.1 Methodology and Results The Central Coast region of California is susceptible to a number of hazards. This HMP profiles the most significant of these hazards. Historical data, catastrophic potential, relevance to the jurisdiction, and the probability and potential magnitude of future occurrences were all used to reduce and prioritize the list of hazards to those most relevant to San Luis Obispo County. Using existing natural hazards data and input gained through planning meetings during both the 2014 HMP and 2019 update, the HMPC agreed upon a list of hazards that could affect San Luis Obispo County. The following table explains the changes in the hazards profiled in 2014 and the 2019 update. Bolded hazards are new to the plan. Table 5-1 Updates to Hazards Profiled, 2014 Plan and 2019 Update 2019 Hazards How and Why Identified Comments Adverse weather: extreme heat, freeze, hail, wind, dense fog, tornado, thunderstorm In 2014 Plan Extreme heat added; drought removed and addressed as a separate hazard Agricultural pest infestation and plant disease, marine invasive species In 2014 Plan Tree mortality included. Biological agents (naturally occurring) In 2014 Plan Pandemic flu, food and water borne illness. Also addressed in other planning mechanisms but a concern to county and history of events. Include Vector Borne Disease Coastal Storm/Coastal Erosion/Sea Level Rise In 2014, sea level rise recommended by HMPC Dam Incidents New in 2014, recommended by HMPC and 2014 FEMA review; identified in local HMPs; in GP Safety Element Includes flooding from excess releases and failures. Drought and Water Shortage In 2014 Plan as part of adverse weather Separated out from adverse weather as its own hazard as nature of hazard is unique and different consequences; includes ground and surface water shortage; agricultural and viticulture impacts Earthquake (including fault rupture, groundshaking, liquefaction) In 2014 Plan Floods In 2014 Plan Includes riverine and stormwater drainage and levee failure; coastal flooding addressed in coastal storms section DMA Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type of all-natural hazards that can affect the jurisdiction. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-3 2019 Hazards How and Why Identified Comments Landslides and Debris Flow In 2014 Plan Debris flow included due to potential from wildfire burns Subsidence New in 2014, recommended by HMPC; identified in Paso Robles HMP Consequence of drought due to overdraft of aquifers. Tsunami and seiche In 2014 Plan Wildfire In 2014 Plan Human Caused: Hazardous Materials New in 2014, recommended by HMPC; In 1999 General Plan Safety Element; County EOP and several emergency response plans Includes Fixed Facility and Transportation, Radiological Accidents, Oil spills, Natural Gas Pipeline Rupture & Storage Facilities Climate Change/Long term climate variability In 2014 Plan Climate change considerations incorporated in the hazard profiles to describe how the frequency and intensity of hazards could be altered in the future In alphabetical order, the natural hazards identified and investigated for the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan include: •Adverse Weather -Extreme Heat -Thunderstorm/Heavy Rain/ Lightening/Freeze/Hail/Dense Fog -High Wind/Tornado •Agricultural Pest Infestation and Plant Disease/Marine Invasive Species •Biological Agents (naturally occurring) •Coastal Storm/Coastal Erosion/Sea Level Rise •Dam Incidents •Drought and Water Shortage •Earthquake •Flood -Levee Failure •Landslide and Debris Flow •Subsidence •Tsunami •Wildfire Human Caused Hazards •Hazardous Materials -Fixed Facility -Transportation -Radiological Accidents -Oil Spills -Natural Gas Pipeline Rupture & Storage Facilities ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-4 The 2019 HMP update included a significant re-evaluation of the hazards with the latest, best available data. Hazards data from San Luis Obispo County, California Governor’s Office of Emergency Services (CA- OES), FEMA, the National Oceanic and Atmospheric Administration, and many other sources were examined to assess the significance of these hazards to the planning area. The update process included a comprehensive, parcel-level risk analysis with GIS where available data permitted. Many new maps and tables were added that capture the potential losses. Additional details on the loss analysis, including a breakdown of hazard losses by jurisdiction and property type can be referenced in Appendix E and the jurisdictional annexes. Overall Hazard Significance Summary Overall hazard significance was based on a combination of Geographic Area, Probability of Future Occurrence and Potential Magnitude/Severity as defined below. The individual ratings are based on or interpolated from the analysis of the hazards in the sections that follow. During the 2019 San Luis Obispo County HMP update the individual ratings and significance of the hazards was revisited and updated. Public concern was also considered via input at public meetings and an online survey. Table 5-2 San Luis Obispo County Hazard Significance Hazard Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance Adverse Weather: Thunderstorm/Heavy Rain/Hail/Lighting/Dense Fog/Freeze Significant Likely Negligible Medium Adverse Weather: High Wind/Tornado Significant Likely Negligible Low Adverse Weather: Extreme Heat Extensive Occasional Negligible Low Agricultural Pest Infestation and Disease Limited Highly Likely Negligible Medium Biological Extensive Occasional Critical Medium Dam Incidents Limited Unlikely Critical Medium Drought and Water Shortage Extensive Likely Critical High Earthquake Extensive Occasional Critical High Flood Significant Likely Critical Medium Landslides and Debris Flow Significant Likely Critical Medium Coastal Storm/Coastal Erosion/Sea Level Rise Limited Likely Limited Medium Subsidence Significant Occasional Negligible Low Tsunami and Seiche Significant Occasional Limited Medium Wildfire Extensive Likely Critical High Human Caused: Hazardous Materials Limited Highly Likely Negligible Low ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-5 Geographic Area Limited: Less than 10% of planning area Significant: 10-50% of planning area Extensive: 50-100% of planning area Probability of Future Occurrences Highly Likely: Near 100% chance of occurrence in next year or happens every year. Likely: Between 10 and 100% chance of occurrence in next year or has a recurrence interval of 10 years or less. Occasional: Between 1 and 10% chance of occurrence in the next year or has a recurrence interval of 11 to 100 years. Unlikely: Less than 1% chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years. Magnitude/Severity (Extent) Catastrophic—More than 50 percent of property severely damaged; shutdown of facilities for more than 30 days; and/or multiple deaths Critical—25-50 percent of property severely damaged; shutdown of facilities for at least two weeks; and/or injuries and/or illnesses result in permanent disability Limited—10-25 percent of property severely damaged; shutdown of facilities for more than a week; and/or injuries/illnesses treatable do not result in permanent disability Negligible—Less than 10 percent of property severely damaged, shutdown of facilities and services for less than 24 hours; and/or injuries/illnesses treatable with first aid Significance Low: minimal potential impact Medium: moderate potential impact High: widespread potential impact Other Hazards Considered Other hazards were noted by the HMPC and public to potentially consider in the HMP update. Some of these hazards have the potential to do damage or harm but since the focus of this plan is on natural hazards, per the DMA requirements, they are not profiled further; in some cases they are currently addressed in other planning mechanisms or have had limited historic impacts: •Expansive Soils •Radon •Tree mortality/hazardous trees in developed areas •Human-Wildlife conflicts •Energy Shortage •Civil Disturbance/Disorder •Terrorism •Cyber Threat •Transportation Incidents/emergencies •Well Stimulation & Hydraulic Fracturing 5.1.2 Disaster Declaration History One method the HMPC used to identify hazards was researching past events that triggered federal and state emergency or disaster declarations in the planning area. Federal and state disaster declarations may be granted when the severity and magnitude of an event surpasses the ability of the local government to respond and recover. Disaster assistance is supplemental and sequential. When the local government’s capacity has been surpassed, a state disaster declaration may be issued, allowing for the provision of state assistance. Should the disaster be so severe that both the local and state governments’ capacities are exceeded, a federal emergency or disaster declaration may be issued allowing for the provision of federal assistance. In other words, a presidential disaster declaration puts federal recovery programs in place to help disaster victims, business, and public agencies. The federal government may issue a disaster declaration through FEMA, the U.S. Department of Agriculture (USDA), or the Small Business Administration (SBA). FEMA also issues emergency declarations, which are more limited in scope and without the long-term federal recovery programs of major disaster declarations (Farm Service Agency 2018). The quantity and types of damage are the determining factors. This section focuses on state and federal disaster and emergency declarations. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-6 The communities throughout San Luis Obispo are among the many in California that are susceptible to disaster. Details on federal and state disaster declarations were obtained by the HMPC, FEMA, and the California Office of Emergency Services (Cal OES) and compiled in chronological order in Table 5-3. A review of state and federal declared disasters indicates that San Luis Obispo County received 26 state proclamations between 1950 and March 2017, 22 of which also received federal disaster declarations. Of the 26 state declarations, 19 were associated with flooding (13 of the flooding events which were related to severe winter storms and heavy rains; 1 was associated with coastal flooding; and 3 were flooding and mudslides); 3 were for drought (not including declaration issued by the USDA); 2 were for freeze; ; 1 was for earthquake; and 2 were for wildfire. Since 2012, there have been 13 drought declarations issued by the Secretary of Agriculture in San Luis Obispo County, 9 of which were Fast Track Secretarial disaster designations. According to the Secretary of Agriculture, a Fast Track designation is for a severe drought and provides an automatic designation when during the growing season any portion of the county meets the severe drought intensity value for eight consecutive weeks. Refer to the Drought hazard profile for more information of Disaster Declarations from the Secretary of Agriculture related to drought events. This disaster history (combined federal and state) suggests that San Luis Obispo County experiences a major event worthy of a disaster declaration every 2.6 years. The County has a 39 percent chance of receiving a disaster declaration in any given year. With the exception of the declarations for earthquake and wildfire, every declaration resulted directly or indirectly from severe weather. Similarly, most disaster- related injuries to people and damage to property and crops resulted from severe weather. Further, a review of these events helps San Luis Obispo County and its jurisdictions identify risk reduction targets and ways to improve capabilities to avoid large-scale hazard events in the future. Table 5-3 San Luis Obispo County’s State and Federal Disaster Declarations, 1950-2018 Hazard Type Disaster # Year State Proclamation Federal Declaration Location Damage* Floods OCD 50-01 1950 11/21/50 -- Statewide 9 deaths; $32,183,000 Floods DR-28 1955 12/22/55 12/23/55 Statewide 74 deaths; $200,000,000 Severe Storms –Flood -- 1958 4/2/58 4/4/58 Statewide 13 deaths; several injuries $24,000,000 Severe Storms –Flood -- 1963 2/14/164 -- Northern California – Boundaries of SLO county and 3 other counties up to the Oregon Border -- Severe Winter Storms – Flood DR-223 1967 12/1/1966 1/2/1967 San Luis Obispo (and 7 other counties) $28,761,041 Flood DR-253 1969 -- 1/26/1969 San Joaquin County (and 39 other counties) 47 deaths; 161 injuries $300,000,000 -1~11-1-~ ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-7 Hazard Type Disaster # Year State Proclamation Federal Declaration Location Damage* Offshore Oil Platform Spill -- 1969 -- -- Coastal Areas of Southern California -- Severe Winter Storms – Coastal Flooding DR-364 1973 1/30/1973 2/8/1973 San Luis Obispo County (and 5 other counties) $17,998,250 Drought -- 1976 2/9/76, 2/13/76, 2/24/76, 3/26/76, 7/6/76 -- San Luis Obispo County (and 30 other counties) $2,664,000,000 Drought EM-3023 1977 -- 1/20/1977 San Luis Obispo County -- Severe Winter Storms- Flood DR-547 1978 2/1/1978 2/15/1978 San Luis Obispo County (and 13 other counties) 14 deaths, 21 injuries, $117,802,785 Severe Winter Storms- Flood DR-677 1982 - 1983 12/8/1982- 3/21/1982 2/9/1983 San Luis Obispo County (and 43 other counties) $523,617,032 Wildfire – Las Pilitas Fire DR-739 1985 7/1/1985 7/18/1985 San Luis Obispo County (and 6 other counties) 3 deaths, 470 injuries, $64,845,864 Burned 75,000 acres from Las Pilitas area to SLO. Portions of the City of SLO was evacuated. Train Derailment -- 1986 -- -- Grover Beach Evacuations, Road closures Freeze USDA and SBA declaration 1987 - - San Luis Obispo - Drought 1988 1/1/1988- 12/31/1988 - Statewide - Drought USDA 1990 1/1990- 7/13/1990 - - - Extreme Cold Weather/ Freeze DR-894 1990 12/19/1990- 1/18/1991 2/11/1991 San Luis Obispo County (32 other counties) $856,329,675 ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-8 Hazard Type Disaster # Year State Proclamation Federal Declaration Location Damage* Hwy 41 Fire GP 94-02 1994 8/24/1994 -- San Luis Obispo County 12 injuries, $6,382,235 Burned 48,531 acres, 42 homes, and 61 other structures Severe Winter Storms - Flood DR-1044 1995 1/6/95- 3/14/96 1/13/1995 San Luis Obispo County (and 42 other counties) 11 deaths, $221,948,347 Severe Winter Storms - Flood DR-1046 1995 Proclaimed 1/10/1995 San Luis Obispo County (all counties except Del Norte) 17 deaths, $132,040,111 Highway 58 Fire Local Proclamation of Emergency 1996 - - San Luis Obispo Burned 106,668 acres Highway 166/Logan Fire - 1997 - - San Luis Obispo Burned 50,000 acres Severe Winter Storm- Flood DR-1155 1997 1/2/1997- 1/31/1997 1/4/1997 San Luis Obispo County (and 47 other counties 8 deaths, $194,352,509 Severe Winter Storms- Flood DR-1203 1998 Proclaimed 2/9/1998 San Luis Obispo County (42 other counties) 17 deaths, $385,141,192 Severe Storms- Flood DC 2001-01 2001 3/1/2001 - San Luis Obispo County (and 2 counties) $2,248,000 estimated in damages throughout county. Arroyo Grande levee breached on south side. Earthquake - San Simeon Earthquake DR-1505 2003 12/23/2003 1/13/2004 San Luis Obispo County (and Santa Barbara County) 2 deaths estimated $239,000,000 in damages, response and recovery costs Parkfield Earthquake - - 9/2004 - San Luis Obispo Minor damages Hurricane Katrina - Economic EM-3248 2005 -- 9/13/2005 Statewide $763,576 Winter Storms -Flood DR-1628 2005 - 2006 -- 2/3/2006 San Luis Obispo County (and 29 counties + statewide HM) 1 death; $203,050,747 ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-9 Hazard Type Disaster # Year State Proclamation Federal Declaration Location Damage* Freeze DR-1689 2007 -- 3/13/2007 San Luis Obispo County (and 12 other counties) $2,700,400 Winter Storms -Flood DR-1952 2010 - 2011 12/1/2010 1/26/20/11 San Luis Obispo County (and 12 counties) Most severe damages in areas of South County, particularly Oceano area. $66,318,201 Tsunami DR-1968 2011 3/11/2011 4/18/2011 Statewide - Freezing Temperature, High Winds, Excessive Rain S3255 2012 3/1/2012 - 4/30/2012 (begin to end date) 6/9/2012 (Sec. Ag Approval date) San Luis Obispo County -- Hail Storm, Rain, cold temperatures S3320 2012 4/11/2012- 4/13/2012 (begin to end dates) 8/3/2012 (Sec. of Ag approval date) San Luis Obispo County -- Drought Local Emergency 2014 - 2017 -- -- San Luis Obispo County Drought 2014 January 17, 2014 – April 7, 2017 -- Statewide -- Intense Thunderstorms - 2015 - - Paso Robles 3.6” of rain in 8 hours, causing water and mud damage to 20-30 homes Cuesta Fire - 2015 - - Santa Margarita A portion of the community of Santa Margarita was evacuated Rain and Wind S4003 2016 4/8/2016 – 5/6/2016 (begin to end dates) 7/27/2016 (Sec. of Ag. approval date) San Luis Obispo County -- ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-10 Hazard Type Disaster # Year State Proclamation Federal Declaration Location Damage* Severe Weather including excessive rainfall and high winds S4164 2016 3/3/2016- 6/1/2016 (begin to end dates) 3/31/2017 (Sec. of Ag approval date) San Luis Obispo County -- Excessive rain, high winds, cold temperatures, and hail S4170 2016 3/1/2016- 5/7/2016 (begin to end dates) 4/28/2017 (Sec. of Ag approval date) San Luis Obispo County -- Chimney Fire FM-5146 2016 8/15/2016 - Nacimiento Lake area 46,344 acres burned, 49 residential type structures destroyed, 21 other structures destroyed, 8 damaged. Hearst Castle was closed for some time. Severe Storms- Flooding and Mudslides DR-4301 2017 - 2/14/2017 San Luis Obispo County (and 33 other counties) $39,956,354 Severe Storms -Flooding and Mudslides DR-4305 2017 2/10/2017 3/16/2017 San Luis Obispo County (and 21 other counties) $14,320,716 Severe Storms -Flooding and Mudslides DR-4308, GP 2017-03 2017 3/7/2017 4/1/2017 San Luis Obispo County (and 41 counties and 1 tribe) 8 deaths; $119,834,925 (DR) $331,137 (GP) Freeze S4350 2018 2/20/2018 7/18/2018 (Sec. of Ag approval date) San Luis Obispo County -- Source: 2018 California State Hazard Mitigation Plan, FEMA, USDA *Damage amount, deaths and inuries reflect totals for all impacted counties 5.1.3 Climate Change Considerations Summary The County acknowledges that climate change is occurring and has begun to plan for it as seen by the EnergyWise Plan and ClimateWise Integrated Climate Change Adaptation Planning in San Luis Obispo County report. County climate change projections include: ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-11 •An increase in temperature between 2.1 and 3.9 degrees by 2045 and between 4.1 and 7.6 degrees by 2085 •Annual average precipitation decreases up to 4.2 inches or increase up to 1.5 inches by 2045 and decrease by 4.73 inches or increase by .88 inches by 2085 •3.3 to 4.6 feet in sea level rise by 2100 •Increase in area of the county burned by wildfire from 3.7% to 6.8-7.3% by 2045 and to 8.1-8.5% by 2085. •Negative impacts on wildlife due to reduced water supply, rising sea levels, and an increase in wildfire and flooding events •Negative impacts on agricultural productivity due to higher temperatures, decrease in water supply and shifts in seasonal changes •Deteriorating public health due to decrease in water supplies and increase risk of wildfire, which have detrimental effects on air quality •Decreased supply of fresh water due to higher temperatures and continued population growth •Increased severity of flood events based on climate model projections that predict less frequent rainfall events, but with greater severity The important consideration for hazard mitigation is that climate change is exacerbating the hazards which are already identified and profiled. For example, it can be expected that coastal storm surge will become more of a threat as sea level rises. Additional specifics associated with the hazards are discussed in the Climate Change Considerations portion of each hazard profile. 5.1.4 Overview of Hazard Identification and Risk Assessment Subsection 5.3 contains detailed hazard profiles for the identified hazards. Each hazard profiled includes the following subsections: •Hazard/Problem Definition—This section gives a description of the hazard and associated issues followed by details on the hazard specific to the San Luis Obispo County planning area. •Geographic Area – This section gives a spatial description of the potential location or areas of San Luis Obispo County where the hazard expected to impact. •Extent (Magnitude/Severity)– This section gives a description of the potential strength or magnitude of the hazard as it pertains to San Luis Obispo County. •Previous Occurrences—This section contains information on historical incidents, including impacts where known. Historical incident worksheets were used to capture information from participating jurisdictions on past occurrences. •Probability of Future Occurrence—The frequency of past events is used in this section to gauge the likelihood of future occurrences. Where possible, frequency was calculated based on existing data. It was determined by dividing the number of events observed by the number of years on record and multiplying by 100. This gives the percent chance of an event happening in any given year (e.g., three droughts over a 30-year period equates to a 10 percent chance of a drought in any given year). The likelihood of future occurrences is categorized into one of the following classifications: -Highly Likely — Near 100 percent chance of occurrence in next year or happens every year. -Likely — Between 10 and 100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-12 -Occasional — Between 1 and 10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years. -Unlikely — Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years. •Climate Change Considerations - This describes the potential for climate change to affect the frequency and intensity of the hazard in the future •Vulnerability - Following the hazard profiles is a vulnerability assessment for each identified hazard. The assessment was conducted through the study of potential impacts to the following specific sectors: -General Property -People -Critical Facilities and Infrastructure -Economy -Historic, Cultural, and Natural Resources -Future Development -Risk Summary - Each vulnerability assessment includes a risk summary of the key issues/problems based on threat, vulnerability and consequence to the planning area and jurisdictions from the specific hazard. Data used to support this assessment included the following: •County GIS data (hazards, base layers, and assessor’s data); •Statewide GIS datasets to support mitigation planning; •State of California Hazard Mitigation Plan 2018; •San Luis Obispo County Hazard Mitigation 2014; •Jurisdictional Hazard Mitigation Plans; •Cal FIRE datasets; •California’s Fourth Climate Change Assessment: Central Coast Region Report; •US Forest Service GIS datasets; •FEMA’s HAZUS-MH GIS-based critical facility inventory data; •Written descriptions of inventory and risks provided by the jurisdictions; •Online data sources (cited where applicable); •Data and information from existing plans and studies; and •Input from planning team members and staff from the County and local, state, and federal agencies. 5.2 Asset Summary 5.2.1 Assets Exposure As a starting point for analyzing the Planning Area’s vulnerability to identified hazards, the HMPC used a variety of data to define a baseline against which all disaster impacts could be compared. If a catastrophic disaster was to occur in the Planning Area, this section describes significant assets exposed or at risk in the Planning Area. Data used in this baseline assessment included: •Total assets at risk; •Critical facility inventory; •Cultural, historical, and natural resources; and ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-13 •Population growth and land use/development trends. Total Assets at Risk Parcel data was provided by ParcelQuest, a third-party service working alongside the San Luis Obispo County Assessor’s Office to compile property information. This data provided the baseline for an inventory of the total exposure of developed properties within the county and helps to ensure that the updated HMP reflects changes in development. It is important to note that depending on the nature and type of hazard event or disaster, it is generally the value of the infrastructure or improvements to the parcels that are of concern or at risk. Generally, the land itself is not a total loss, but may see a reduction in value. Thus, the parcel analysis excludes land value. Parcel Exposure and Preparations for Analysis Building counts and valuations in this plan are based on data from the County Assessor’s Office as well as ParcelQuest. The ParcelQuest GIS layer contains the assessor’s information, and for the purpose of parcel analysis and exposure calculations only parcels with improved values were used, except for exempt or government properties (which by definition do not include an improvement value and is one limitation that results in the total improvement values underestimating the actual value). “Improved” parcels have an improvement value greater than zero. Contents values were also estimated, as a percentage of building value based on their property type, using FEMA/HAZUS guidelines. Content value estimates are based on 100% of the structure value for commercial and agriculture structures, 150% of the structure value for industrial structures, and finally 50% for residential structures. Improvement values were added to contents values to arrive at the total structure values for all properties in the parcel layer. The parcel layer, originally in the form of polygons, was then converted into points based on the center (or centroid) of a parcel to approximate building locations. Table 5-4, Table 5-5, and Table 5-6 below summarize the count and value of improved properties, contents, and total values for the property inventory grouped by jurisdiction, as well as exposure values by property type, and finally the exposure values by property type for the unincorporated areas of the County. Table 5-4 San Luis Obispo County Total Exposure by Jurisdiction Jurisdiction Property Count Improved Value Content Value Total Value Arroyo Grande 6,693 $1,608,652,049 $865,870,064 $2,474,522,113 Atascadero 10,298 $2,311,286,428 $1,223,381,289 $3,534,667,717 City of San Luis Obispo 14,083 $4,412,540,270 $2,664,377,282 $7,076,917,552 Grover Beach 4,713 $866,176,076 $462,306,623 $1,328,482,699 Morro Bay 5,320 $1,113,527,653 $579,407,494 $1,692,935,147 Paso Robles 10,714 $2,821,913,364 $1,632,765,187 $4,454,678,551 Pismo Beach 4,885 $1,439,073,785 $761,589,312 $2,200,663,097 Unincorporated 46,878 $12,207,641,760 $6,261,161,189 $18,468,802,949 TOTAL 103,584 $26,780,811,385 $14,450,858,440 $41,231,669,825 Source: Wood analysis based on ParcelQuest and San Luis Obispo County Assessor’s Office data 2019 ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-14 Table 5-5 San Luis Obispo County Total Exposure by Property Type Property Type Property Count Improved Value Content Value Total Value Agricultural 623 $503,096,233 $503,096,233 $1,006,192,466 Commercial 3,972 $2,382,146,177 $2,382,146,177 $4,764,292,354 Government/Utilities 2,704 $10,842,823 -- $10,842,823 Other/Exempt/Misc. 3,701 $695,078,084 -- $695,078,084 Residential 73,954 $18,260,098,270 $9,130,049,135 $27,390,147,405 Multi-Family Residential 9,116 $2,265,198,982 $1,132,599,491 $3,397,798,473 Mobile/Manufactured Homes 3,748 $494,287,198 $247,143,599 $741,430,797 Residential: Other 3,414 $1,331,071,111 $665,535,556 $1,996,606,667 Industrial 266 $260,192,166 $390,288,249 $650,480,415 Vacant 2,086 $578,800,341 -- $578,800,341 TOTAL 103,584 $26,780,811,385 $14,450,858,440 $41,231,669,825 Source: Wood analysis based on ParcelQuest and San Luis Obispo County Assessor’s Office data 2019 Table 5-6 Total Exposure by Property Type in Unincorporated San Luis Obispo County Location Property Type Property Count Improved Value Content Value Total Value Unincorporated Agricultural 592 $455,950,949 $455,950,949 $911,901,898 Commercial 799 $382,693,827 $382,693,827 $765,387,654 Government/Utilities 1,932 $7,465,764 -- $7,465,764 Other/Exempt/Misc. 1,904 $234,552,034 -- $234,552,034 Residential 34,081 $9,553,005,276 $4,776,502,638 $14,329,507,914 Multi-Family Residential 1,890 $409,203,080 $204,601,540 $613,804,620 Mobile/Manufactured Homes 3,067 $377,655,433 $188,827,717 $566,483,150 Residential: Other 807 $280,364,775 $140,182,388 $420,547,163 Industrial 85 $74,934,754 $112,402,131 $187,336,885 Vacant 1,721 $431,815,868 -- $431,815,868 TOTAL 46,878 $12,207,641,760 $6,261,161,189 $18,468,802,949 Source: Wood analysis based on ParcelQuest and San Luis Obispo County Assessor’s Office data 2019 Critical Facility Inventory For the purposes of this plan, a critical facility is defined as one that is essential in providing utility or direction either during the response to an emergency or during the recovery operation. The County of San Luis Obispo uses the following four categories to describe critical assets: •Emergency Services – Facilities or centers aimed at providing for the health and welfare of the whole population (e.g., hospitals, police, fire stations, emergency operations centers, evacuation shelters, schools). •Lifeline Utility Systems – Facilities and structures such as potable water treatment plants, wastewater, oil, natural gas, electric power and communications systems. •Transportation Systems – These include railways, highways, waterways, airways and city streets to enable effective movement of services, goods and people. •High Potential Loss Facilities – These include nuclear power plants, dams, and levees. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-15 The specific critical facilities analyzed in this plan are provided in Table 5-7 and Table 5-8 and displayed in Figure 5-1. A general summary of the critical facilities based on their categories just described is provided in Table 5-7 below. A portion of the critical facilities data was provided by the San Luis Obispo County Planning & Building and GIS Departments; supplemental data from the Homeland Infrastructure Foundation-Level Data (HIFLD) was used to capture additional facilities such as law enforcement facilities and centers, communications facilities, emergency operations centers, schools, and urgent care facilities among others. The specific facilities that were provided by the County or its departments came from five data layers: airports, power plants, water/wastewater treatment plants, California energy commission substations, and fire facilities. The other types or additional facilities were obtained at the federal level from the HIFLD dataset. Furthermore, participating jurisdictions identified additional or supplemental assets on a data collection guide worksheet or in previous LHMPs which may capture more facilities and additional details not within the main critical facility GIS database. For a list of assets and vulnerabilities within specific jurisdictions, please refer to the jurisdictional annexes and Appendix E. Vulnerabilities of specific facilities to specific hazards were analyzed with a GIS overlay analysis where data permitted. The results are discussed within each hazard’s vulnerability section in subsection 5.3 and detailed in Appendix E. Table 5-7 Critical Facilities Types by Category Emergency Services Lifeline Utility Systems Transportation Systems High Potential Loss Facilities Colleges / Universities AM Transmission Towers Airports Power Plants Day Care Facilities Broadband Radio Service & Educational Broadband Service Transmitters Emergency Medical Service Stations Energy Commission Facilities Fire Stations Cellular Towers Hospitals Electric Substations Local Law Enforcement FM Transmission Towers Nursing Homes Microwave Service Towers Private Schools Paging Transmission Towers Public Schools TV Analog Station Transmitters Supplemental Colleges TV Digital Transmitters Urgent Care Water Treatment Facilities Veterans Affairs Medical Facilities Wastewater Treatment Plants Source: San Luis Obispo County Planning & Building/GIS; HIFLD. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-16 Figure 5-1 Critical Facilities in San Luis Obispo County PACIFIC OCEAN ■ Emergency Services □ High Potential Loss Facilit ies □ Lifeline Utility Systems □ Transportation Systems Waterways Lakes -+--+ Ra ilroads Highway Freeway LJ Cities Counties ••• Map compiled B/2019 ; intended for planning purposes only. Data Source : San Luis O bispo County, US Census T IGER Database , CA Open Data Portal , HIFLD 201 7, LAFCO , CSDs Monterey !' .t"' ,1 ~._ Santa Barbara . . 10 20 40 Mile s Tulare ~ Kern · ~ d 1 Ventura N A Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-17 Table 5-8 Summary of Critical Facilities in San Luis Obispo County by Jurisdiction Jurisdiction Category Critical Facility Type Count Arroyo Grande Emergency Services Day Care Facilities 8 Emergency Medical Service Stations 2 Fire Stations 1 Hospitals 2 Local Law Enforcement 1 Nursing Homes 2 Private Schools 4 Public Schools 5 Urgent Care 1 High Potential Loss Facilities Power Plants 1 Lifeline Utility Systems FM Transmission Towers 1 Paging Transmission Towers 1 Energy Commission Facilities 3 Transportation Systems Airports 1 Total 33 Atascadero Emergency Services Day Care Facilities 13 Emergency Medical Service Stations 2 Fire Stations 3 Hospitals 1 Local Law Enforcement 1 Nursing Homes 8 Private Schools 2 Public Schools 9 Supplemental Colleges 1 Urgent Care 1 High Potential Loss Facilities Power Plants 2 Lifeline Utility Systems Microwave Service Towers 2 TV Analog Station Transmitters 1 Energy Commission Facilities 1 Total 47 Grover Beach Emergency Services Day Care Facilities 2 Emergency Medical Service Stations 1 Fire Stations 1 Local Law Enforcement 1 Private Schools 1 Public Schools 3 Lifeline Utility Systems Microwave Service Towers 2 Water Treatment Facilities 1 Total 12 Morro Bay Emergency Services Day Care Facilities 4 Emergency Medical Service Stations 2 Fire Stations 2 Local Law Enforcement 1 Nursing Homes 2 Public Schools 2 High Potential Loss Facilities Power Plants 1 Lifeline Utility Systems Microwave Service Towers 5 Wastewater Treatment Plants 1 Energy Commission Facilities 2 Total 22 Paso Robles Emergency Services Colleges / Universities 1 Day Care Facilities 14 Emergency Medical Service Stations 1 ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-18 Jurisdiction Category Critical Facility Type Count Fire Stations 3 Local Law Enforcement 1 Nursing Homes 2 Private Schools 3 Public Schools 12 Supplemental Colleges 1 Urgent Care 1 High Potential Loss Facilities Power Plants 1 Lifeline Utility Systems AM Transmission Towers 1 FM Transmission Towers 1 Microwave Service Towers 12 Water Treatment Facilities 1 Energy Commission Facilities 2 Transportation Systems Airports 1 Total 58 Pismo Beach Emergency Services Day Care Facilities 2 Emergency Medical Service Stations 2 Fire Stations 3 Local Law Enforcement 1 Public Schools 2 Urgent Care 1 Lifeline Utility Systems Microwave Service Towers 6 Wastewater Treatment Plants 1 Transportation Systems Airports 1 Total 19 San Luis Obispo Emergency Services Colleges / Universities 2 Day Care Facilities 18 Emergency Medical Service Stations 5 Fire Stations 4 Hospitals 3 Local Law Enforcement 2 Nursing Homes 3 Private Schools 5 Public Schools 12 Urgent Care 1 Veterans Affairs Medical Facilities 1 Lifeline Utility Systems AM Transmission Towers 1 FM Transmission Towers 1 Microwave Service Towers 52 Wastewater Treatment Plants 1 Energy Commission Facilities 7 Transportation Systems Airports 2 Total 120 Unincorporated Emergency Services Colleges / Universities 2 Day Care Facilities 29 Emergency Medical Service Stations 25 Fire Stations 29 Hospitals 1 Local Law Enforcement 8 Nursing Homes 5 Private Schools 4 Public Schools 40 High Potential Loss Facilities Power Plants 7 Lifeline Utility Systems AM Transmission Towers 5 ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-19 Jurisdiction Category Critical Facility Type Count Broadband Radio Service & Educational Broadband Service Transmitters 5 Cellular Towers 19 Electric Substations 2 FM Transmission Towers 33 Microwave Service Towers 368 Paging Transmission Towers 6 TV Analog Station Transmitters 15 TV Digital Transmitters 4 Wastewater Treatment Plants 5 Water Treatment Facilities 7 Energy Commission Facilities 8 Transportation Systems Airports 10 Total 637 Grand Total 948 Source: San Luis Obispo County Planning & Building/GIS, Community Service Districts, HIFLD Cultural, Historical, and Natural Resources Assessing the County of San Luis Obispo’s vulnerability to disaster also involves inventorying the natural, historical, and cultural assets of the area. This step is important for the following reasons: • The community may decide that these types of resources warrant a greater degree of protection due to their unique and irreplaceable nature and contribution to the overall economy. • In the event of a disaster, an accurate inventory of natural, historical and cultural resources allows for more prudent care in the disaster’s immediate aftermath when the potential for additional impacts is higher. • The rules for reconstruction, restoration, rehabilitation, and/or replacement are often different for these types of designated resources. • Natural resources can have beneficial functions that reduce the impacts of natural hazards, for example, wetlands and riparian habitat which help absorb and attenuate floodwaters and thus support overall mitigation objectives. Cultural Resources Historical resources are buildings, structures, objects, places, and areas that are eligible for listing in the National Register of Historic Places (NRHP), the California Register of Historic Resources (CRHR), or the County’s List of Historic Resources, have an association with important persons, events in history, or cultural heritage, or have distinctive design or construction method. San Luis Obispo County has a wealth of historic and prehistoric resources, including sites and buildings associated with Native Americans, Spanish missionaries, immigrant settlers, and military branches of the United States. Native American groups have occupied the County dating back at least 10,000 years, including the Chumash, Salinan, and Yokut tribes. In 1595, the Spanish sailed into San Luis Obispo Bay, near the large Obispeño village of Sepjato, which thereafter greatly changed the aboriginal way of life. In 1769 Gaspar de Portolà and Father Junipero Serra passed through present day San Luis Obispo County with the objective to secure the port and establish missions along his route, and the Mission San Luis Obispo de Tolosa was founded near San Luis Obispo Creek. In 1822, California became a Mexican Territory, and the mission lands gradually became private ranchos via Mexican land grants. After the ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-20 decline of the mission era in the late 1830s, San Luis Obispo County gradually grew from a remote outpost into a thriving agricultural and commercial region with an influx of Euro-American land landholders settling in the area. For purpose of federal actions, a qualified historic resource is defined as a property listed in or formally determined eligible for listing in the NRHP before a disaster occurs. The NRHP is part of a national program to coordinate and support public and private efforts to identify, evaluate, and protect historic and archeological resources. Properties listed include districts, sites, buildings, structures, and objects that are significant in American history, architecture, archeology, engineering, and culture. The National Register is administered by the U.S. Department of the Interior National Park Service. Local and state agencies may consider a broader definition of qualified historic properties in the review, evaluation, and treatment of properties damaged during a disaster. The State of California Office of Historic Preservation can provide technical rehabilitation and preservation services for historic properties affected by a natural disaster. Depending on the hazard, protection could range from emergency preparedness, developing a fire safe zone around sites susceptible to wildfires, or seismically strengthening or structurally reinforcing structures. State and local registers of historic resources provide designated Historical Landmarks, Points of Historical Interest, and Historic Buildings. These resources include, but are not limited to: • The California Register of Historical Resources • The California Historical Landmarks • The California Inventory of Historical Resources • The California Points of Historical Interest • The City of San Luis Obispo Cultural Heritage Committee • The History Center of San Luis Obispo has created an inventory of the Historic Buildings of San Luis Obispo County. County Historical Resources may be designated on a federal, state, or local level. Local historical resources may be within the jurisdictions of an Area Plan. Historical resources designated under a regional or local plan are provided in Table 5-9. Vulnerabilities of specific historic buildings to specific hazards were analyzed with a GIS overlay analysis where data permitted. The results are discussed within each hazard’s vulnerability section in subsection 5.3. Table 5-9 San Luis Obispo County Historical Resources and Area Plans Historical Resource Year Area Plan Rotta Winery 1856 Adelaida Area Plan Adelaida Cemetery 1891 Adelaida Area Plan York Mountain Winery 1882 Adelaida Area Plan San Marcos Cemetery 1889 Adelaida Area Plan Willow Creek Cemetery 1911 Adelaida Area Plan Estrella Adobe Church 1878 El Pomar-Estrella Area Plan Creston Cemetery -- El Pomar-Estrella Area Plan Pozo Saloon 1865 Las Pilitas Area Plan ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-21 Historical Resource Year Area Plan Santa Margarita de Cortona 1775 Salinas River Area Plan Mission San Miguel Archangel 1797 Salinas River Area Plan Bethel Lutheran Church 1887 Salinas River Area Plan Banning School 1896 San Luis Obispo Area Plan Hansen Barn -- San Luis Obispo Area Plan Independence School -- San Luis Obispo Area Plan Octagon Barn 1900 San Luis Obispo Area Plan Vasquez-Hollister Adobe 1800 San Luis Obispo Area Plan Dana Adobe 1839 South County Inland Area Plan Dana House 1882 South County Inland Area Plan Pacific Coast Railroad Depot 1881 South County Inland Area Plan Old St. Joseph's Church 1902 South County Inland Area Plan Runels Home - Dana Street 1886 South County Inland Area Plan Hearst Castle 1919 North Coast Area Plan Van Gordon Archaeological Site -- North Coast Area Plan Bianchini House 1889 North Coast Area Plan The Paul Squibb House 1877 North Coast Area Plan Port San Luis Lighthouse 1890 San Luis Bay Coastal Area Plan Huasna School 1907 Huasna-Lopez Area Plan Adelaida School 1917 Adelaida Area Plan J.F. MacGillivray Residence 1879 Adelaida Area Plan Geneseo School 1886 El Pomar-Estrella Area Plan Creston Community Church 1886 El Pomar-Estrella Area Plan Rancho Huasna Sparks Adobe 1850 Huasna-Lopez Area Plan Tar Springs Ranch -- Huasna-Lopez Area Plan Porter Ranch House 1890 Huasna-Lopez Area Plan C.H. Plillips House 1886 Salinas River Area Plan Rios Caledonia Adobe 1830 Salinas River Area Plan Marre House 1932 San Luis Bay Area Plan-Inland Tognazzini General Store 1908 San Luis Obispo Area Plan Los Osos School House 1872 Estero Area Plan Captain James Cass House 1872 Estero Area Plan Los Berros Schoolhouse 1890 South County Inland Area Plan ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-22 Historical Resource Year Area Plan The Sebastian Store 1860 North Coast Area Plan Canet Adobe 1840 Estero Area Plan Lyman House 1895 San Luis Obispo Area Plan Rinconada School 1880 El Pomar-Estrella Area Plan Chandler House (Webster) 1882 El Pomar-Estrella Area Plan Linne School 1891 El Pomar-Estrella Area Plan Los Berros Adobe Barn 1860 South County Inland Area Plan Hearst Ranch Headquarters -- North Coast Area Plan Eight-Mile House 1877 Salinas -- San Luis Bay Area Plan-Inland Avila Valley Historic Site 2 -- San Luis Bay Area Plan-Inland Avila Valley Historic Site 1 -- San Luis Bay Area Plan-Inland Temple of The People, Halcyon 1903 San Luis Bay Area Plan-Inland Price Adobe -- San Luis Bay Area Plan-Inland Captain James Cass House & Adjacent Buildings 1872 Estero Area Plan Cayucos Pier -- Estero Area Plan Spooner Residence -- Estero Area Plan The Bluebird Motel -- North Coast Area Plan Carroll's Blacksmith Shop -- North Coast Area Plan Heart's Ease -- North Coast Area Plan Ian's Restaurant -- North Coast Area Plan Robin's Restaurant -- North Coast Area Plan The Squibb House -- North Coast Area Plan The Brambles Restaurant -- North Coast Area Plan Rigdon Hall Restaurant -- North Coast Area Plan The Red House -- North Coast Area Plan The Bianchini House -- North Coast Area Plan The Bucket of Blood Saloon -- North Coast Area Plan Louis Maggetti's House -- North Coast Area Plan Camozzi's -- North Coast Area Plan Soto's Market -- North Coast Area Plan The Leffingwell House -- North Coast Area Plan The Olallieberry Inn -- North Coast Area Plan ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-23 Historical Resource Year Area Plan The Lull House -- North Coast Area Plan The Old Santa Rosa Chapel -- North Coast Area Plan The Thorndyke House -- North Coast Area Plan The First Presbyterian Church -- North Coast Area Plan The Bank of Cambria -- North Coast Area Plan Arthur Beale House 1928 North Coast Area Plan Ah Louis Store 1874 San Luis Obispo Area Plan Admin\Veterans memorial bldg 1918 Salinas River Area Plan Coffee T. Rice House 1886 San Luis Bay Area Plan-Coastal Dallidet Adobe 1859 San Luis Obispo Area Plan Morro Rock 1769 Estero Area Plan Mission SLO De Tolosa 1772 San Luis Obispo Area Plan Ortega-Price Adobes 1840 San Luis Bay Area Plan-Inland Santa Margarita Asistencia 1775 Salinas River Area Plan Source: County of San Luis Obispo Office of Planning and Building Lists of designated historical resources change periodically, and they may not include those currently in the nomination process and not yet listed. Additionally, as defined by the National Environmental Policy Act (NEPA), any property over 50 years of age is considered a historic resource and is potentially eligible for the National Register. Thus, in the event that the property is to be altered, or has been altered, as the result of a major federal action, the property must be evaluated under the guidelines set forth by NEPA. Structural mitigation projects are considered alterations for the purpose of this regulation. Cultural resources defined in California Environmental Quality Act (CEQA) Section 15064.5 as include prehistoric and historic archaeological resources; historic-period resources (buildings, structures, area, place, or objects). Archaeological resources reflect past human activity extending from Native American prehistoric cultures throughout the early 20th century. The artifacts left by previous occupants may be encountered in small to large residential sites, or special use areas. Many cultural and historical resources in the County are vulnerable to several hazards due to location and the nature of their construction. Some of these risks include earthquakes, wildfires, coastal storms, or adverse weather. Tribal Cultural Resources Tribal cultural resources are defined in Public Resources Code (PRC) Section 21074.1 as a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American tribe. A Native American tribe is defined as “a federally recognized California Native American tribe or a non-federally recognized California Native American tribe that is on the contact list maintained by the Native American Heritage Commission”. Traditional tribal cultural places are defined in PRC Sections 5097.9 and 5097.993 to include ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-24 sanctified cemeteries, places of worship, religious or ceremonial sites, or sacred shrines, or any historic, cultural, or sacred site that is listed on or eligible for the CRHR including any historic or prehistoric ruins, burial grounds, or archaeological site. Cultural and tribal resources are governed primarily by federal, state, and local laws that regulate potential impacts to such resources. State regulations that were established to encourage the preservation and protection of traditional tribal cultural resources include: • Assembly Bill 52 (Public Resources Code [PRC] Section 21080.3.1): mandates early tribal consultation prior to and during CEQA review to consider tribal cultural values in determination of project impacts and mitigation. • Senate Bill 18 (Government Code 655352.3): requires cities and counties to consult with Native American tribes early during broad land use planning efforts on both public and private lands, prior to site- and project-specific land use decisions. Consultation is intended to encourage preservation and protection of traditional tribal cultural places by developing treatment and management plans that might include incorporating the cultural places into designated open spaces. • State Executive Order B-10-11 (2011) established the Governor’s Tribal Advisor position and established Administration Policy to encourage State Agencies to communicate and consult with Californian tribes regarding tribal cultural resources. Natural Resources Natural resources issues of the County include those regarding: geology, soils, hydrology, plant and wildlife ecology, resources laws, and natural resource public policy (County of San Luis Obispo 2019a). San Luis Obispo County is diverse in natural resources, exemplified by its creeks and rivers that drain inland mountains in confluence with the Pacific Ocean, coastal dunes and cliffs, oak woodlands, extensive mountainous landscapes, and grasslands in the Carrizo Plain National Monument. Interfaces of urban areas and natural landscapes provide accessible walking and hiking trails with sweeping views of the peaks and valleys of the county’s mountain ranges, and the Pacific Ocean. Natural resources within the county includes several managed areas and protected habitats, including the State Marine Conservation Areas (SMCA), State Marine Reserves (SMR), State Marine Recreational Management Area (SMRMA), state parks and beaches, and state game refuges. These areas support ecologically significant habitats where endangered or threatened species occur, including designated critical habitat and nesting and foraging sites for migratory bird species. Natural resources are important to include in benefit/cost analyses for future projects and may be used to leverage additional funding for mitigation projects that also contribute to community goals for protecting sensitive natural resources. Inventory and awareness of natural resource assets is vital to meeting conservation objectives. For example, protecting wetland areas provides sensitive habitat protection as well as floodwater conveyance and storage, which further enhances public safety. Natural resource maps can be found in the Planning & Building section of the County of San Luis Obispo web site (County of San Luis Obispo 2019b). Natural resources also exhibit varied levels of resiliency to anthropogenic impacts, climate change, and natural hazards such as flooding, drought, coastal storms or wildfire. Climate change is one of the most substantial threats to conserving the biodiversity and ecological habitat of the County (OPR 2019). Habitat resiliency is exemplified in coastal habitat migration to inland areas as a result to sea level rise, and ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-25 recovery of burn areas following a wildfire. For example, grassland vegetation burned by wildfire typically regrows and recovers within five or so years. Natural and Beneficial Functions Natural and beneficial functions of a region can describe hydrologically significant, environmentally sensitive, and ecologically productive areas that perform many natural functions. Floodplains can have natural and beneficial functions including water storage and conveyance, protection of water quality, and recharge of groundwater (Walton County 2018). Wetlands function as natural sponges that trap and slowly release surface water, rain, snowmelt, groundwater and flood waters. Trees, root mats, and other wetland vegetation also slow the speed of floodwaters and distribute them more slowly over the floodplain. This combined water storage and braking action lowers flood heights and reduces erosion. Wetlands within and downstream of urban areas are particularly valuable, counteracting the greatly increased rate and volume of surface water runoff from pavement and buildings. The holding capacity of wetlands helps control floods and can help limit impacts to agricultural as well as urban areas. Preserving and restoring wetlands, together with other water retention, can often provide the level of flood control otherwise provided by expensive dredge operations and levees. Natural resources provide scenic value and are vital to recreation in the County. Recreational functions provided by natural resources include parks and campgrounds, water-oriented sports and activities such as boating, swimming, and hiking. Wildlife resources in floodplains can be managed for observation, and recreational hunting and fishing, as coastal floodplains are recognized for their importance to estuarine and marine fisheries. Coastal beaches, dunes, banks, and tidal flats all play roles in protecting landward structures from destructive coastal storms and erosion. Other beneficial functions of County natural resources include diverse habitats for aquatic and terrestrial species, as well as natural crops and timber. Special Status Species To further understand natural resources that may be particularly vulnerable to a hazard event, as well as those that need consideration when implementing mitigation activities, it is important to identify at-risk species (endangered and threatened species) in the Planning Area. The US Fish and Wildlife Service maintains a list of federally-listed threatened and endangered species for the country, which can be queried at the state or even county levels. The California Department of Fish and Wildlife also maintains species lists and accounts for threatened and endangered species. State and federal laws protect the habitat of these species through the environmental review process. Species of special concern may additionally include species that meets the State definition of threatened or endangered but has not been formally listed, experiences seriously population declines or habitat decline, or has naturally small populations exhibiting high susceptibility to population decline (Department of Fish and Wildlife 2019). Table 5-10 summarizes San Luis Obispo County’s special status animal species as indicated in the Fish and Wildlife Service database, within the Environmental Conservation Online System. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-26 Table 5-10 Threatened and Endangered Species in San Luis Obispo County Common Name Scientific Name Group Federal Status State Status Arroyo (=arroyo southwestern) toad Anaxyrus californicus Amphibians Endangered None Bank swallow Riparia Birds None Threatened Bald eagle Haliaeetus leucocephalus Birds None Endangered Blunt-nosed leopard lizard Gambelia silus Reptiles Endangered Endangered Beach spectaclepod Dithyrea maritima Flowering Plants None Threatened Buena Vista Lake ornate shrew Sorex ornatus relictus Mammals Endangered None California black rail Laterallus jamaicensis coturniculus Birds None Threatened California ridgway’s rail Rallus obsoletus Birds Endangered Endangered California condor Gymnogyps californianus Birds Endangered Endangered California jewelflower Caulanthus californicus Flowering Plants Endangered Endangered California least tern Sterna antillarum browni Birds Endangered Endangered California red-legged frog Rana draytonii Amphibians Threatened None California seablite Suaeda californica Flowering Plants Endangered None California tiger salamander Ambystoma californiense Amphibians Threatened Threatened Camatta canyon amole Chlorogalum purpureum var. reductum Flowering Plants Threatened Rare Chorro Creek bog thistle Cirsium fontinale var. obispoense Flowering Plants Endangered Endangered Conservancy fairy shrimp Branchinecta conservatio Crustaceans Endangered None Delta smelt Hypomesus transpacificus Fishes Threatened Endangered El Segundo blue butterfly Euphilotes battoides allyni Insects Endangered None Gambel's watercress Rorippa gambellii Flowering Plants Endangered Threatened Gaviota Tarplant Deinandra increscens ssp. villosa Flowering Plants Endangered Endangered Giant garter snake Thamnophis gigas Reptiles Threatened Threatened Giant kangaroo rat Dipodomys ingens Mammals Endangered Endangered Hearst’s manzanita Arctostaphylos hookeri ssp. hearstiorum Flowering Plants None Endangered Indian Knob mountainbalm Eriodictyon altissimum Flowering Plants Endangered Endangered Kern mallow Eremalche kernensis Flowering Plants Endangered None Kern primrose sphinx moth Euproserpinus euterpe Insects Threatened None La Graciosa thistle Cirsium loncholepis Flowering Plants Endangered Threatened Least Bell's vireo Vireo bellii pusillus Birds Endangered Endangered Leatherback sea turtle Dermochelys coriacea Reptiles Endangered None Longhorn fairy shrimp Branchinecta longiantenna Crustaceans Endangered None Marbled murrelet Brachyramphus marmoratus Birds Threatened Endangered Marsh Sandwort Arenaria paludicola Flowering Plants Endangered Endangered Monterey spineflower Chorizanthe pungens var. pungens Flowering Plants Threatened None Morro Bay kangaroo rat Dipodomys heermanni morroensis Mammals Endangered Endangered Morro manzanita Arctostaphylos morroensis Flowering Plants Threatened None ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-27 Common Name Scientific Name Group Federal Status State Status Morro shoulderband (=Banded dune) snail Helminthoglypta walkeriana Snails Endangered None Nelson’s antelope ground squirrel Ammospermophilus nelsoni Mammals None Threatened Nipomo Mesa lupine Lupinus nipomensis Flowering Plants Endangered Endangered Olive ridley sea turtle Lepidochelys olivacea Reptiles Threatened None Pismo clarkia Clarkia speciosa ssp. immaculata Flowering Plants Endangered None Purple amole Chlorogalum purpureum var. purpureum Flowering Plants Threatened None Salt marsh bird's-beak Cordylanthus maritimus ssp. maritimus Flowering Plants Endangered Endangered San Luis Obispo fountain thistle Cirsium fontinale var. obispoense Flowering Plants None Endangered San Joaquin kit fox Vulpes macrotis mutica Mammals Endangered Threatened San Joaquin wooly-threads Monolopia (=Lembertia) congdonii Flowering Plants Endangered None Smith's blue butterfly Euphilotes enoptes smithi Insects Endangered None Southern sea otter Enhydra lutris nereis Mammals Threatened None Southwestern willow flycatcher Empidonax traillii extimus Birds Endangered Endangered Steelhead - south-central California coast DPS Oncorhynchus mykiss irideus pop. 9 Fishes Threatened None Steelhead - southern California coast DPS Oncorhynchus mykiss irideus pop. 10 Fishes Endangered None Surf thistle Cirsium rhothophilum Flowering Plants None Threatened Spreading navarretia Navarretia fossalis Flowering Plants Threatened None Swainson’s hawk Buteo swainsoni Birds None Threatened Tidewater goby Eucyclogobius newberryi Fishes Endangered None Tipton kangaroo rat Dipodomys nitratoides Mammals Endangered Endangered Vernal pool fairy shrimp Branchinecta lynchi Crustaceans Threatened None Western snowy plover Charadrius nivosus Birds Threatened None Yellow-billed Cuckoo Coccyzus americanus Birds Threatened Endangered Source: US Fish and Wildlife Service – Environmental Conservation Online System, 2019 Population, Growth and Development Trends The County has a population of approximately 280,119 people, with a wide range of income levels and demographics (US Census Bureau 2017). Over 85% of the County identifies as white, including 22% of Hispanics. The Countywide median household income in 2017 was estimated to be $67,175 and median family income was estimated at $83,084. Additionally, US Census Bureau data estimates that 13.8% of the population is below the federal poverty level and that at least 37.1% of the County’s population is considered low-income relative to State Income Limits. Critical demographic information includes: 4.6% of the civilian labor force over 16 years old is unemployed; 81.5% of the population age 25 and older has at least a high school degree, with 34.1% having a bachelor’s degree or higher (United States Census Bureau 2017); and 40.3% of occupied housing units are renter occupied (U. S. Census Bureau 2010). ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-28 Populations in San Luis Obispo County that may face disproportionate risks include the elderly, those already affected by diseases, outdoor and migrant workers, people living in coastal and inland floodplains, those living at the wildland-urban interface, the student population, institutionalized individuals (especially the state hospital), and non-English speaking individuals. Social vulnerability data and considerations are described in subsection 4.4.1 and further noted in each hazard’s Vulnerability: People section in subsection 5.3. As part of the planning process, the HMPC analyzed changes in growth and development, both past and future, and examined these changes in the context of hazard-prone areas, and how the changes in growth and development affect loss estimates and vulnerability. Table 5-11 illustrates the moderate pace of population growth in the County of San Luis Obispo dating back to 2000 and population trends for each incorporated jurisdiction in the county. Table 5-11 Population Growth for the County of San Luis Obispo from 2000-2017 Municipality 2000 2010 2017 Population Growth 2000-2017 Arroyo Grande 15,851 17,252 17,971 13% Atascadero 26,409 28,310 29,797 13% Grover Beach 13,067 13,156 13,524 3% Morro Bay 10,350 10,234 10,568 2% Paso Robles 24,284 29,793 31,409 29% Pismo Beach 8,551 7,655 8,060 -6% City of San Luis Obispo 44,174 45,119 46,997 6% Countywide 246,681 269,637 280,119 14% Source: US Census Bureau American FactFinder, 2019 Future Population Growth The California Department of Transportation (Cal Trans) recently published population growth predictions for the County of San Luis Obispo (Cal Trans, 2018). The report forecasts economic and employment development using historical evidence from 2012 to 2017 and includes several predictions from 2018 to 2050. According to this report, which seeks to describe the local socioeconomic profile of the county, San Luis Obispo is expected to continue to grow at a slow rate, averaging 0.4% per year between 2018 and 2023. The majority of the growth will be from migration entering the county. This summary states that, by 2050, the total population could be 298,795. Development Trends In order to assess where development is expected to take place (or has recently taken place) across the county with regards to hazards, new construction permits and entitlements for residential and commercial properties were obtained, in spatial format, since the last update of this plan (2014 through early 2019). These permits were then mapped as points and color-coded based on the year in which they were submitted. Figure 5-2 displays the centroids that were generated from each permit polygon, mapped by year of submittal to the Office of Planning & Building at the County, while Table 5-12 summarizes the total building construction permits by year, case type, and work class. The data indicates a dispersal pattern of development trends with some clusters along the Highway 101 corridor, notably between Paso Robles and Atascadero and south of Arroyo Grande. I I I I ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-29 To further associate these building construction permits with natural hazards in the county and be able to narrow down potential vulnerable areas to this expected development (hence assessing risk to future construction of commercial and residential buildings), a spatial overlay analysis was performed that intersected the centroid points and the hazard layers. With this overlay analysis, summaries similar to those conducted for parcel and critical facility analyses could be delivered. These assessments are discussed in more detail in each of the hazard sections, under the Development Trends sections. ••• Section 5 Risk Assessment County of San Luis Obispo Local Hazard Mitigation Plan | October 2019 Page 5-30 Figure 5-2 Building Construction Permits in San Luis Obispo County from 2014 to Early 2019 PACIFIC OCEAN 0 2019 Bldg . Permits 0 2018 Bldg . Permits . 2017 Bldg . Pe rmits • 2016 Bldg . Pe rmits • 2015 Bldg . Permits . 2014 Bldg . Permits \/Vaterways Lakes -+--+ Rai lroads --Highway --Freeway ••• Map compiled 3/2019 ; inte nded for planning purposes o nl y. Da ta Source: San Luis Ob ispo County, us Census TIGER Database, CA Open Data Portal Monterey 0 • 0 •• d-·~- .,._.... 0 0 -.. . ~1 ,/?,J<·r o 0 Santa N:fa~garita Lake 10 r t,,,'r, •L op ez-Lake . " , ...<S randt 20 Tulare Posn('reek Kern Soda L ake Santa Barbara Ventura 40 Mi les N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-31 Table 5-12 Total Building Construction Permits by Case Type and Work Class Year Case Type Work Class Count 2014 Land Use Conditional Use Permit 29 Minor Use Permit 130 PMTC - Commercial Permit New Structure 223 PMTR - Residential Permit 560 TOTAL 942 2015 Land Use Conditional Use Permit 167 Minor Use Permit 128 PMTC - Commercial Permit New Structure 180 PMTR - Residential Permit 514 TOTAL 989 2016 Land Use Conditional Use Permit 36 Minor Use Permit 117 PMTC - Commercial Permit New Structure 151 PMTR - Residential Permit 819 TOTAL 1,123 2017 Land Use Conditional Use Permit 26 Minor Use Permit 146 PMTC - Commercial Permit New Structure 186 PMTR - Residential Permit 483 TOTAL 841 2018 Land Use Conditional Use Permit 78 Minor Use Permit 133 PMTC - Commercial Permit New Structure 155 PMTR - Residential Permit 602 TOTAL 968 2019 (up to Feb) Land Use Conditional Use Permit 4 Minor Use Permit 21 PMTC - Commercial Permit New Structure 30 PMTR - Residential Permit 85 TOTAL 140 GRAND TOTAL 5,003 Source: San Luis Obispo County Planning & Building ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-32 5.3 Hazard Analysis and Risk Assessment 5.3.1 Adverse Weather: General Adverse weather is generally any destructive weather event, but usually occurs in the San Luis Obispo County as localized thunderstorms that bring heavy rain and strong winds that occur most often during the winter and spring months. For this plan, adverse weather is broken down as follows: • Thunderstorm/Heavy Rain/Hail/Lighting/Dense Fog/Freeze • High Wind/Tornado • Extreme Heat The proximity to the Pacific Ocean both moderates and exaggerates certain types of adverse weather. Winter storms impacting coastal portions of the County tend to be more extreme than in the inland portions. The ocean’s influence is also a significant factor in moderating extreme hot and cold temperatures, hail storms and other cold weather events. These events are rare and short lived, causing little if any life-threatening situations and only occasional significant damage to property or agricultural concerns. The HMPC determined that extreme heat should also be profiled and analyzed within adverse weather for this 2019 Plan Update. Extreme heat events are projected to increase throughout the state which will have impacts on people’s health, as well as indirect impacts effects such as increased vulnerability and risk to wildfires and drought. The National Oceanic and Atmospheric Administration’s National Center for Environmental Information (NCEI) has been tracking adverse weather since 1950. Their Storm Events Database contains data on the following: all weather events from 1993 to 2017 (except from 6/1993-7/1993); and additional data from the Storm Prediction Center, which includes tornadoes (1950-1992), thunderstorm winds (1955-1992), and hail (1955-1992). This database contains 115 storm events that occurred in San Luis Obispo County between January 1, 1950, and December 31, 2018. The table below summarizes these events. Table 5-13 NCEI Hazard Event Reports for San Luis Obispo County, 1950-2018* Type # of Events Property Loss ($) Crop Loss ($) Deaths Injuries Excessive Heat/Heat 3 0 0 0 0 Flash Floods 5 0 0 0 0 Floods 10 0 0 0 0 Frost/Freeze 2 0 30,400,000 0 0 Hail 4 0 0 0 0 Heavy Rain 9 5,000,000 0 1 0 High Winds/Thunderstorm Winds 27 4,050,000 0 0 0 Tornado/Funnel Cloud 39 $0 0 3 5 High Surf 4 0 0 0 0 Waterspout 2 0 0 0 0 Wildfire 4 290,000 0 0 0 Winter Weather/Winter Storm 6 0 0 1 2 Totals 115 9,340,000 30,400,000 5 7 Source: National Center for Environmental Information Storm Events Database, www.ncdc.noaa.gov/stormevents/ *Hazards with wide extents have losses which reflect larger zones that extend beyond San Luis Obispo County ~ l l I l I ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-33 The NCEI table above summarizes adverse weather events that have occurred in San Luis Obispo County from 1950 to 2018. Only a few of the events actually resulted in state and federal disaster declarations. It is interesting to note that different data sources capture different events during the same time period, and often different information specific to the same events. While the HMPC recognizes these inconsistencies, this data provides value in depicting the County’s “big picture” hazard environment. As previously mentioned, a majority of San Luis Obispo County’s state and federal disaster declarations have been a result of severe winter weather. The climate of the county is influenced by the effects of the Santa Lucia Range and the Pacific Ocean. The northern portion of the county where the mountains end at the ocean experience heavier rainfall amounts compared to the southern portion of the county. Figure 5-3 below, depicts the average annual precipitation in the county and shows how precipitation differs throughout. Note, the purple lines and text on the map represent the County’s Watershed Groups that are included in the 2018 Integrated Regional Water Management Plan update. Due to the size of the county and changes in elevation and climate, weather conditions can vary greatly. The National Weather Service provides forecasts for three zones within the county: central coast, interior valley, and mountains and the County Public Works Department has stream and rain gauges in four areas of the county; North County Coastal Area, North County Inland Area, City of San Luis Obispo Area, and South County Area. To give a holistic picture of the various weather conditions the hazard profiles that follow provide information, where possible, from four weather stations: San Luis Obispo Poly Tech (San Luis Obispo Area, elevation: 330 feet), Morro Bay Fire Department (North County Coastal Area, elevation: 115 feet), Paso Robles (North County Inland Area, elevation: 700 feet) and Pismo Beach (South County Area, elevation: 39 feet). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-34 Figure 5-3 San Luis Obispo County Annual Precipitation, 1971-2000 Source: County of San Luis Obispo Public Works Department, Water Resources Montere y, Count}'. Kern County, ••• County of San Luis Obispo Public Works Wate r Resources Annual Precipitation Legend Highways =US HIGHWAY -STAT E HIGHWAY D :~e~~e~~~sJ;o8~ounty Annual Precipitation From 1971 to2000' Inches □0-10 D 10 .01 -15 0 15 .01 -20 0 20 .01-30 0 30.0-40 .,40 1. A modified USGS Watershed Boundary Da taset (\NBD) Hydrological Unit 10 included in the draft 2016 Integrated Regional Wat.er Management (IR\,",,/M ) Plan update (http://slocountywater.org/'irwm} 2 PRISM Climate Data from Nortl'r.Yesi Atlianoe for Computational Sc;ence and Engineering N Date Created: 3/28/20 19 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-35 5.3.2 Adverse Weather: Thunderstorm/Heavy Rain/Dense Fog/Freeze Hazard/Problem Definition A majority of adverse weather experienced in San Luis Obispo takes place in the winter months as heavy rain and thunderstorm events sometimes accompanied by high winds, dense fog, hail and freeze events. High winds and tornado events are profiled in 5.3.3. Approximately 10 percent of the thunderstorms that occur each year in the United States are classified as severe. A thunderstorm is classified as severe when it contains one or more of the following phenomena: hail that is three-quarters of an inch or greater, winds in excess of 50 knots (57.5 mph), or a tornado. San Luis Obispo’s weather is influenced by the Pacific Ocean and routine climate patterns such as El Niño. El Niño is the warm phase of the El Niño-Southern Oscillation, a pattern found in the tropical Pacific when there are fluctuations in temperatures between the ocean and atmosphere. During El Niño, the surface winds across the entire tropical Pacific are weaker than normal and the ocean surface is at above-average temperatures in the central and eastern tropical Pacific Ocean (L’Heureux 2014). El Niño typically develops over North America during the winter season causing the severe winter storms the County often experiences. This climate pattern occurs every few years and brings with it above-average rain and snow across the southern region of United States, especially in California. Atmospheric rivers, another climate pattern that leads to adverse weather in the County, are responsible for up to 50 percent of California’s precipitation annually and 65 percent seasonally (Arcuni, 2019). An atmospheric river (AR) is a long, narrow region of the atmosphere, like a river in the sky, that transports most of the water vapor outside of the tropics. ARs can be 300 miles wide, a mile deep and more than 1,000 miles long and carry an amount of water vapor roughly the same as the average flow of water at the mouth of Mississippi River (NOAA, 2015). Warm water storms over the Pacific Ocean lead to evaporation and create a high concentration of moisture in the air. While prevailing winds create the distinctive river shape, which is often compared “to a fire hose pointed at California” (Arcuni, 2019). When an atmospheric river reaches land, it releases the water vapor in the form of rain or snow. Atmospheric rivers play an important role in the global water cycle and are closely tied to both water supply and flooding risk. Research suggests that atmospheric rivers contributed to the collapse of both Orville Dam spillways in February 2017 (NASA Global Hydrology Resource Center), as well as the winter flooding in 1861-1862, which completely inundated Sacramento and is considered the worst flood event in California’s history (Ingram, 2013). When an atmospheric river forms in the tropical regions of the pacific near Hawaii it is known as a “Pineapple Express”. This type of atmospheric river can produce as much as five inches in one day (NOAA, 2018). In 2018 two Pineapple Express ARs hit California causing significant heavy precipitation events throughout state. Hail is formed when water droplets freeze and thaw as they are thrown high into the upper atmosphere by the violent internal forces of thunderstorms. Hail is sometimes associated with severe storms within the San Luis Obispo County planning area. Hailstones are usually less than two inches in diameter and can fall at speeds of 120 miles per hour (mph). Severe hailstorms can be quite destructive, causing damage to roofs, buildings, automobiles, vegetation, and crops. Lightning is defined as any and all of the various forms of visible electrical discharge caused by thunderstorms. Thunderstorms and lightning are usually (but not always) accompanied by rain. Severe ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-36 lighting events in San Luis Obispo County are rare, although they do take place occasionally. Refer to the Previous Occurrences section below for the narrative on a 2019 adverse weather event. Intra-cloud lightning is the most common type of discharge. This occurs between oppositely charged centers within the same cloud. Usually it takes place inside the cloud and looks from the outside of the cloud like a diffuse brightening that flickers. However, the flash may exit the boundary of the cloud, and a bright channel, similar to a cloud-to-ground flash, can be visible for many miles. Cloud-to-ground lightning is the most damaging and dangerous type of lightning, though it is also less common. Most flashes originate near the lower-negative charge center and deliver negative charge to earth. However, a large minority of flashes carry positive charge to earth. These positive flashes often occur during the dissipating stage of a thunderstorm’s life. Positive flashes are also more common as a percentage of total ground strikes during the winter months. This type of lightning is particularly dangerous for several reasons. It frequently strikes away from the rain core, either ahead or behind the thunderstorm. It can strike as far as 5 or 10 miles from the storm in areas that most people do not consider to be a threat (see Figure 5-4). Positive lightning also has a longer duration, so fires are more easily ignited. And, when positive lightning strikes, it usually carries a high peak electrical current, potentially resulting in greater damage. Figure 5-4 Cloud to Ground Lighting Source: National Weather Service Pueblo Office San Luis Obispo’s climate is described as a mild Mediterranean climate; a freeze refers to a particularly cold spell of weather where the temperature drops below 32 degrees, most typically in the early morning hours. Usually these cold spells will last only two or three days when the ocean influence will overcome the cold front and the early morning temperatures will return to the normal 45 to 55-degree range. Rainfall during these periods may result in snowfall in the higher elevations of the county. ••• boftfrom the blue + intracloud flash + updraft + Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-37 Dense fog in San Luis Obispo County reduces visibility making driving more dangerous. A fog advisory issued for San Luis Obispo County in October 2011 warned visibility could be as low as a quarter mile and reduce suddenly with denser patches. In March 2012 another fog advisory anticipated less than ¼ of normal visibility. The National Weather Service issues dense fog advisories when appropriate and suggests slowing down on the road, using headlights at all times, and leaving plenty of distance from other vehicles. Geographic Area Thunderstorms are generally expansive in size. The entire county is susceptible to any of the effects of a severe thunderstorm, including hail and heavy rain. As noted at the beginning of the Adverse Weather profile, the proximity to the Pacific Ocean and the mountain ranges in the county both moderate and exaggerate certain types of adverse weather depending on where the storm event has occurred. Extent (Magnitude/Severity) Extent for adverse weather, particularly severe storms that involve heavy rain and hail can be measured according to hail by diameter sizes. The National Weather Service (NWS) classifies hail by diameter size, and corresponding everyday objects to help relay scope and severity to the population. Table 5- 2 below indicates the hailstone measurements utilized by the NWS. There is no clear distinction between storms that do and do not produce hailstones. Nearly all severe thunderstorms probably produce hail aloft, though it may melt before reaching the ground. Multi-cell thunderstorms produce many hailstones, but not usually the largest hailstones. In the life cycle of the multi-cell thunderstorm, the mature stage is relatively short so there is not much time for growth of the hailstone. Supercell thunderstorms have sustained updrafts that support large hail formation by repeatedly lifting the hailstones into the very cold air at the top of the thunderstorm cloud. In general, hail 2 inches (5 cm) or larger in diameter is associated with supercells (a little larger than golf ball size which the NWS considers to be 1.75 inch.). Non-supercell storms are capable of producing golf ball size hail. Common problems associated with severe storms include the loss of utilities or immobility. Loss of life is uncommon but can occur during severe storms. Immobility can occur when roads become impassable due to dense fog, heavy rains causing flooding, downed trees, or a landslide. Fog specifically poses a risk to commuters and driving conditions as fog typically forms rapidly in the early morning hours. Fog can have devastating effects on transportation corridors in the county. Nighttime driving in the fog is dangerous and multi-car pileups have resulted from drivers using excessive speed for the conditions and visibility. Loss of utilities, specifically power lines can occur due to downed trees, high winds and heavy snows. While snow accumulation is unlikely within the San Luis Obispo planning area, high winds and downed trees are known to result in power outages. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-38 Table 5-14 Hail Measurements Average Diameter Corresponding Household Object .25 inch Pea .5 inch Marble/Mothball .75 inch Dime/Penny .875 inch Nickel 1.0 inch Quarter 1.5 inch Ping-pong ball 1.75 inch Golf-Ball 2.0 inch Hen Egg 2.5 inch Tennis Ball 2.75 inch Baseball 3.00 inch Teacup 4.00 inch Grapefruit 4.5 inch Softball Source: National Weather Service Lightning is measured by the Lightning Activity Level (LAL) scale, created by the National Weather Service to define lightning activity into a specific categorical scale. The LAL is a common parameter that is part of fire weather forecasts nationwide. The San Luis Obispo County is at risk to experience lightning in any of these categories. The LAL is reproduced in Table 5-15. Table 5-15 Lightning Activity Level Scale Lightning Activity Level LAL 1 No thunderstorms LAL 2 Isolated thunderstorms. Light rain will occasionally reach the ground. Lightning is very infrequent, 1 to 5 cloud to ground strikes in a five-minute period LAL 3 Widely scattered thunderstorms. Light to moderate rain will reach the ground. Lightning is infrequent, 6 to 10 cloud to ground strikes in a five-minute period. LAL 4 Scattered thunderstorms. Moderate rain is commonly produced. Lightning is frequent, 11 to 15 cloud to ground strikes in a five-minute period. LAL 5 Numerous thunderstorms. Rainfall is moderate to heavy. Lightning is frequent and intense, greater than 15 cloud to ground strikes in a five-minute period. LAL 6 Dry lightning (same as LAL 3 but without rain). This type of lightning has the potential for extreme fire activity and is normally highlighted in fire weather forecasts with a Red Flag warning. Source: National Weather Service ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-39 The heavy precipitation that San Luis Obispo County and all of California experiences is often the result of an atmospheric river. Atmospheric rivers are categorized by a unit of measurement known as the Integrated Water Vapor Transport (IVT), which takes into account the amount of water vapor in the system and the wind that moves it around. For a storm to be classified as an atmospheric river it has to reach an IVT threshold of 250 units; 1,000 IVT or more is considered to be “extreme” (Arcuni, 2019). In 2019 a system for categorizing the strength and impacts of atmospheric rivers was developed by the Center for Western Weather and Water Extremes (CW3E), out of the Scripps Institution of Oceanography at UC San Diego. The newly developed scale ranks ARs into five categorizes from weak to exceptional. Unlike the Fujita scale for tornadoes that focuses on potential damages, the AR scale accounts for both storms that may be hazardous and storms that can provide benefits to the local water supply. A category one AR is considered to be primarily beneficial, generally lasting only 24 hours and produces modest rainfall. While a category five AR is considered “exceptional” and primarily hazardous, lasting for several days and associated with heavy rainfall and runoff that may cause significant damages. Table 5-16 below describes the scale further. The center developed the scale as a tool for officials with an operational need to assess flooding potential in their jurisdictions before the storms makes landfall. In both February 2018 and 2019 the West Coast experienced six atmospheric rivers. But as the following figure from the Center for Western Weather and Water Extremes shows, California experienced vastly different precipitation totals due to the location of where the atmospheric river made landfall as well as each atmospheric river’s IVT. Using the AR scale developed by CW3E, the ARs in February 2019 were all considered to be moderate to extreme and concentrated more on California, resulting in heavy precipitation. Table 5-16 Atmospheric River Categories Category Potential Impacts AR Cat 1: Weak Primarily beneficial. For example, a Feb. 2, 2017 AR hit California, lasted 24 hours at the coast, and produced modest rainfall. AR Cat 2: Moderate Mostly beneficial, but also somewhat hazardous. An atmospheric river on Nov. 19-20, 2016 hit Northern California, lasted 42 hours at the coast, and produced several inches of rain that helped replenish low reservoirs after a drought. AR Cat 3: Strong Balance of beneficial and hazardous. An atmospheric river on Oct. 14-15, 2016 lasted 36 hours at the coast, produced 5-10 inches of rain that helped refill reservoirs after a drought, but also caused some rivers to rise to just below flood stage. AR Cat 4: Extreme Mostly hazardous, but also beneficial. For example, an atmospheric river on Jan. 8-9, 2017 that persisted for 36 hours produced up to 14 inches of rain in the Sierra Nevada and caused at least a dozen rivers to reach flood stage. AR Cat 5: Exceptional Primarily hazardous. For example, a Dec. 29, 1996 to Jan. 2, 1997 atmospheric river lasted over 100 hours at the Central California coast. The associated heavy precipitation and runoff caused more than $1 billion in damages. Source: Center for Western Weather and Water Extremes, Scripps Institution of Oceanography at UC San Diego. Scale was developed by F. Martin Ralph Director of CW3E in collaboration with Jonathan Rutz of NWS ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-40 Figure 5-5 Atmospheric River Strength and Land Distribution, February 2018 vs. February 2019 Source: Center for Western Weather and Water Extremes, Scripps Institution of Oceanography at UC San Diego 45 °N 40 °N 35 °N 30 °N February 2018 R~lph/CW3E AR Strtnllli Sc~le I weak : IV! •il0-5oo kg m·' s-1 Moderate : i\/T.S00-7SO kg nr' 1"1 I Strong: IVT•IS0-1000 kg m 'S"' I Extreme:11/T 1000-1250~Rm'1S"1 I Exceptional: IVf) mo kg m I ,.., Feb. 2 'feITT Feb.1 Fe b, 17 145"W 140°W 135°W 130°w ••• 125°W 120°W 115°W 110°W >500 475 425 400 5°N 380 360 340 320 S()O OON 280 260 24-0 ~ 200 1so l5 °N 160 140 120 100 ~o 60 l0 °N 40 20 10 <0,01 mm February 2019 Ra !i!h/CW3E AR strength SUie I weak: IVT =l.'iO-WO kg m-t r' M<l</c ~lt: I\IT =S00-1SO kg n1-I rl I Stroris: IVT=7S0-1000 kg rrf 1)·1 lx!<Crro\': IVT =1 000-USO ki m·J J-1 I l1«t1>'onal :M>12SOl;gm ·t ,.1 ~5 °N -----------------------................ - 140°W 135°W 130°w 125°W 120°W 115°W 110°W Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-41 Previous Occurrences Heavy rains and adverse storms occur in the San Luis Obispo County primarily during the late fall and winter but have a chance of occurring in every month of the year. According to information obtained from the Western Regional Climate Center (WRCC) the majority of precipitation is produced by storms during January and other winter months. Precipitation during the summer months is in the form of rain showers and is rare. Snowstorms, and hailstorms occur infrequently in San Luis Obispo County and severe occurrences of any of these are very rare. Damaging winds often accompany winter storm systems moving through the area and it is the winds experienced during the winter storms that result in the most wind-related damage. Refer to 5.3.3 for information related to wind events. The NCEI records 21 heavy rain, hail and frost/freeze events that have taken place in San Luis Obispo County in the past 68 years (1950 –2018). No dense fog or lightning events have been recorded but does not mean they do not occur in the county; the HMPC noted in the 2014 plan that the National Weather Service issued fog advisories in 2011 and 2012. As shown in the NCEI records heavy rain storms can cause both widespread flooding which can lead to extensive localized drainage issues. In addition to the flooding that often occurs during these storms, strong winds, when combined with saturated ground conditions, can down very mature trees. Refer to the Flood section for more information related to flooding events in the county. Information from the three representative weather stations introduced in subsection 5.3 Adverse Weather: General are summarized below and in Figure 5-6 through Figure 5-11 San Luis Obispo Polytech (Period of Record 1893 to 2012) Information from the closest weather station with the most comprehensive data to represent the City of San Luis Obispo Area, the San Luis Obispo Polytech Weather Station, is summarized below in Figure 5-6 and Figure 5-7. Average annual precipitation in the interior valley is 22.40 inches per year. The highest recorded annual precipitation was 48.76 inches in 1969; the highest recorded precipitation for a 24-hour period is 5.90 inches on January 25, 1969. The lowest recorded annual precipitation was 7.37 inches in 1947. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-42 Figure 5-6 City of San Luis Obispo Area - Monthly Average Total Precipitation (Period of Record 1893 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ Figure 5-7 City of San Luis Obispo Area - Daily Precipitation Average and Extreme (Period of Record 1893-2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ ..... • C •"'4 ..... C 0 •"'4 +,I l'O +,I •"'4 0. •"'4 (.) II) '-~ ••• 5 .5 5 4 .5 4 3 .5 3 2 .5 2 1.5 1 0 .5 0 SAN LUIS OBISPO POLYTECH, CALIFORNIA (047851) Period of Record: 02/01/1893 to 06/10/2016 Jan Feb Mar May Jul Sep pr Jun Aug Oct Nov Dec Day of Year ( Average Total Month l y Precipi ion ) SAN LUIS OBISPO POLYTECH, CALIFORNIA (047851) Period of Record: 02/01/1893 to 06/10/2016 ~ Me:ste:Y-Yo Re:,giOl'ICll CliMC1te: Ce:t'ltu, Jan 1 Mar 1 May 1 Jul 1 Sep 1 Nov 1 Dec 31 Feb 1 ( Apr 1 Jun 1 Aug 1 Oct 1 Dec 1 Day of Year --Extreme Average ) Me:ste:Y-n Re:giOl'ICll Cl iMC1te: Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-43 North County Coastal Area - Morro Bay Fire Department Weather Station (Period of Record 1959 to 2012) Information from the closest weather station with the most comprehensive data to represent the North County Coastal Area of San Luis Obispo, the Morro Bay Fire Department Weather Station, is summarized below in Figure 5-8 and Figure 5-9. Average annual precipitation in the interior valley is 16.74 inches per year. The highest recorded annual precipitation was 37.01 inches in 1995; the highest recorded precipitation for a 24-hour period is 8.82 inches on March 11, 1995. The lowest recorded annual precipitation was 6.18 inches in 2007. Figure 5-8 North County Coastal Area - Monthly Average Total Precipitation (Period of Record 1959 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ ..... 4 • C 3 .5 •"1 ...... s C d 2 .5 ''°1 ~ 2 ~ ~ ·-➔ t.5 0. •"1 (,) 1 f .5 ~ 0 ••• MORRO BAY FIRE DEPT CALIFORNIA (045866) Period of Record: 82/81/1959 to 85/31/2816 Jan Mar t1a1;:1 Jul Sep Nov Feb pr Jun Aug Oct Dec Oa~ of Year ( Average Total Monthl~ Precipitation ) Mitstel"t'I Re9ioric:1l Clil"leltlt Cent.el" Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-44 Figure 5-9 North County Coastal Area - Daily Precipitation Average and Extreme (Period of Record 1959-2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ North County Inland Area - Paso Robles Weather Station (Period of Record 1894 to 2012) Information from the closest weather station with the most comprehensive data to represent the North County Inland Area of the county, Paso Robles Weather Station, is summarized below in Figure 5-10 and Figure 5-11. Average annual precipitation in this region of the county is 15.21 inches per year. The highest recorded annual precipitation was 29.19 inches in 1941; the highest recorded precipitation for a 24-hour period is 5.25 inches on December 6, 1966. The lowest recorded annual precipitation was 4.24 inches in 1947. ...... • C .... ...... C: 0 .... ..., It, ..., .... Q. .... (.) ~ '-0.. ••• MORRO BAY FIRE DEPT, CALIFORNIA (045866) Period of Record: 02/01/1959 to 05/31/2016 Jan 1 Mar 1 t1a!:j 1 Jul 1 Sep 1 Nov 1 Dec 31 Feb 1 Apr 1 Jun 1 Aug 1 Oct 1 Dec 1 Day of Year ( --Extreme -Average ) M.i,st.i:l'n Re9ionol Clir11e1te Cel'ltet' Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-45 Figure 5-10 North County Inland Area - Monthly Average Total Precipitation (Period of Record 1894 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ Figure 5-11 North County Inland Area - Daily Precipitation Average and Extreme (Period of Record 1894-2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ ..... • C •"4 ...,, ..... • C •"4 ...,, C 0 •01 .,.I ft! .,.I •01 Q. •"4 CJ I) '-ii. ••• 3 .5 3 2 .5 2 1 .5 1 0.5 0 5 4,5 4 3 ,5 3 2 .5 2 1 ,5 1 0 .5 0 Jan ( PASO ROBLES, CALIFORNIA (046730) Period of Re c ord: 01/81/1894 to 06/18/2016 Feb Mar Ma~ Jul Sep Apr Jun Aug Oct Nov Da y o f Year Average Total Monthly Precip i tation PASO ROBLES 1 CALIFORNIA (046730) Period of Record: 01/01/1894 to 06/10/2016 Dec J M=t.el"n Rcgion<ill Cli~.:ih Ccnt.l:r- Jan 1 Mar 1 Ma~ 1 Jul 1 Sep 1 Nov 1 Dec 31 Feb 1 Apr 1 Ju n 1 Aug 1 Oct 1 Dec 1 Day of Year ( --Extrel\'le Average ) Western Regioneil Cli~tc Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-46 South County Area - Pismo Beach Weather Station (Period of Record 1949 to 2016) Information from the closest weather station with the most comprehensive data to represent the South County Area of the county, Pismo Beach Weather Station, is summarized below in Figure 5-12 and Figure 5-13. Average annual precipitation in this region of the county is 16.96 inches per year. The highest recorded annual precipitation was 32.58 inches in 1983; the highest recorded precipitation for a 24-hour period is 5.16 inches on January 19, 1969. The lowest recorded annual precipitation was 4.49 inches in 1989. Figure 5-12 South County Area - Monthly Average Total Precipitation (Period of Record 1949 - 2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ ,,... • C: •'"4 ...., ••• .s 1.s l 0,5 0 Jan ( PISMO BEACH, CALIFOR NI A (046943) Period of Record: 07/81/1949 to 06/89/2816 Feb Mar-May Jul Sep Apr Jun Aug Oct Nov Day of Year Ave age Total Monthly Prec1pita ion Dec ) Mc~hl"n Regiohd Climt.e Citnt,e,- Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-47 Figure 5-13 South County Area - Daily Precipitation Average and Extreme (Period of Record 1949-2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ The following table reports the records collected from the NCEI Storm Events Database for heavy rain, hail and frost/freeze events. No dense fog events are reported in the database. Table 5-17 is a summary of the most significant adverse weather events as recorded in the NCEI Storm Events. Table 5-17 San Luis Obispo County Heavy Rain/Hail/Freeze Events, 1950-2018 Event Type Date Magnitude Property Damage Crop Damage Deaths Injuries Heavy Rain 2/20/1996 4-6 in.0 0 0 0 11/ 10/1997 0.50-1.50 in. (coastal) 3.0 in. (mountains) 0 0 0 0 1/10/2001 2-5 in. (coastal)5-10 in. (mountains)0 0 0 0 2/11/2001 2-8 in.0 0 0 0 2/ 24/2001 1-4 in.0 0 0 0 3/4/2001 2-6 in. (coastal)6-13 in. (mountains)0 0 0 0 12/ 27/2004 2-8 in. (coastal)6-13 in. (mountains)0 0 0 0 12/ 30/2004 1-3 in. (coastal3-6 in. (mountains)0 0 1 0 1/7/2005 3-10 in.$5,000,000 0 0 0 Hail 3/6/2001 0.75 in. 0 0 0 0 ..... • C ·.-4 ..... ••• PISMO BEACH, CALIFORNIA (046943) Period of Record! 07/01/1949 to 06/09/2816 5 r==r-----:===================---==i -l.5 .. 3 .5 3 2.5 2 1-: I o.: [ Jan 1 Mar-1 Ma!::I 1 . Jul 1 Se p 1 Nov 1 Dec 31 Feb 1 Apr 1 Jun 1 Aug 1 Oct 1 Dec 1 Day of Year ( --Extreme --Average ) M ,s:tot:l"h R,e9ion<>l CliMQ\ot: Center Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-48 Event Type Date Magnitude Property Damage Crop Damage Deaths Injuries 2/23/2005 0.75 in. 0 0 0 0 5/28/2009 0.75 in. 0 0 0 0 3/22/2017 1 in. 0 0 0 0 Frost/Freeze 12/21/1998 - 0 $83,000,000* 0 0 1/13/2007 - 0 $25,000,000 0 0 Totals $5,000,000 $108,000,000 1 0 Source: NCEI Storm Events Database *Note this recorded crop damage amount is representative of a four-county area Table 5-18 Past Thunderstorm/Heavy Rain/Dense Fog/Freeze Events, 1950-2018 Date of Event Incident Description February 18, 1993 Thunderstorms -A thunderstorm caused damage to many of the same areas as winds to nearly 50 mph. Pea-sized hail was reported at Pismo Beach. Power outages due to lightning strikes were reported in Nipomo and San Luis Obispo. $50,000 in property damage was reported February 20, 1996 Heavy rain in the mountains of San Luis Obispo County led to 4-6 inches of rain and caused urban and small stream flooding and associated mudslides in the steep terrain and along Hwy 1 and 101. February 2, 1998 Along with the strong winds (refer to Table 5-5 for information on the wind event), heavy rain drenched the entire area. On average, rainfall totals ranged from 2 to 8 inches over coastal areas, up to 12 inches in the mountains. Widespread flooding was reported in all areas (refer to the past events table in the Flood section). February 5, 1998 Strong winds, gusting up to 70 mph, knocked down many trees and power lines. Rainfall totals ranged from 1 to 3 inches over coastal areas, up to 6 inches in the mountains. Numerous flooding problems were reported across the area. Most highways, including the 1, 101, 126 and 154 were closed due to flooding or mudslides. December 21-24, 1998 Freeze. An unseasonable cold air mass produced a three-night period of sub-freezing temperatures across Central and Southern California. The California Department of Food and Agriculture reported over $83 million in crop losses over the four-county area. Crop damage in San Luis Obispo was reported to be a total of $5.4 million. 1990 to present (events number more than 5) Very cold Pacific storms brought snow fall to the higher elevations of the county. On rare occasions, it caused damage to the naturally occurring vegetation. This resulted in an increased fire season threat as the damaged vegetation dried out and augmented the normal fuel loading. The snow caused rare transportation impacts on Hwy. 101 at Cuesta Grade and Hwys 41 and 46 at higher elevations. March 4, 2001 A powerful and slow-moving storm brought heavy rain, strong winds and snow to Central and Southern California. Across San Luis Obispo and Santa Barbara counties, rainfall totals ranged from 2 to 6 inches over coastal and valley areas to 6 to 13 inches in the mountains. In San Luis Obispo County, the heavy rain produced numerous flooding. Refer to the Flood section for information related to the resulting flood event. March 6, 2001 A severe thunderstorm produced dime size hail in the community of Santa Margarita. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-49 Date of Event Incident Description December 30, 2004 A powerful Pacific storm brought more heavy rain, snow and flash flooding to Central and Southern California. Total rainfall amounts ranged from 1 to 3 inches on the coastal plain to between 3 and 6 inches in the mountains. Refer to the Flood section for information on the resulting flooding. February 23, 2005 Nickel size hail was reported in a remote area of San Luis Obispo county. January 13-15, 2007 A very cold arctic storm brought widespread freezing temperatures and some gusty offshore winds to the area. Across the agricultural areas of San Luis Obispo, Santa Barbara, Ventura and Los Angeles counties, the freezing overnight temperatures nearly $350 million in crop damages. Widespread freezing conditions were reported across agricultural areas. Total crop damages in San Luis Obispo county were estimated to be around $25 million. May 28, 2009 A severe thunderstorm was reported in San Luis Obispo county near the community of La Panza. Three quarter inch hail was reported by the local fire station. April 2011 In mid-April, a bitter cold weather system sent temperatures plunging to the mid-20's, bringing hail and freezing rain for at least two nights and in some lower elevation areas, three or four. Thousands of acres of vineyards lost newly emerging grape buds, which experts say could amount to 50% of the area's 2011 crop. Loss estimates range from 70 to 80 million dollars. July 19, 2015 Paso Robles received nearly 3.6 inches of rain in less than 8 hours. The intense rainfall (remnant of Hurricane Dolores) eroded bare hillsides located outside the City limits and caused very high volumes of sediment to fill City drainage ways and culverts. 20-30 homes were impacted causing mud and water damage. March 22, 2017 Several strong thunderstorms developed across the Central Coast of California. In Creston, a severe thunderstorm developed, producing one-inch hail. Source: NCEI Storm Events Database, 2014 County LHMP, HMPC In February 2019, San Luis Obispo County experienced severe winter storms that caused heavy rain, hail, and light snow showers in some areas of the county. The National Weather Service issued a freeze warning for the County on February 18th, 2019 that lasted until February 22nd, 2019. The County had been experiencing drought conditions throughout 2018 but received enough rain in the 2019 season to bring it out of the abnormally dry and drought conditions for the first time in 11 years (San Luis Obispo Tribune, 2019). Refer to the Drought section for more information related to drought conditions in the county. On February 25th, 2019 Caltrans announced it would be closing portions of Highway 1 along the Central Coast, in anticipation of a heavy rain event and would not be reopening the highway until the end of that week after the storm passes to allow for crews to inspect and clean up the highway (San Luis Obispo Tribune, 2019). The county continued to experience severe winter storms into March 2019. On March 5th ,2019 a severe thunderstorm, brought heavy rain, thunder and lightning to the South County area. The National Weather Service’s Los Angeles station reported that the region, San Luis Obispo, Santa Barbara, Los Angeles and Ventura counties, received 4,500 lighting strikes including about 2,500 cloud-to-ground strikes (San Luis Obispo Tribune, 2019). At one point the NWS recorded 1,489 in one five-minute stretch alone off the ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-50 coast of Central Coast region (Los Angeles Times, 2019). The county and the region are accustomed to thunderstorms with the occasional lighting strike accompanying the storms, but this amount of lightning strikes in one thunderstorm event it rare. The storm also caused 300 residents in Grover Beach, 149 residents in rural Arroyo Grande and 70 near See Canyon Road in San Luis Obispo for a total 519 residents in the county to lose power due to the winter storm. Power was restored by the next morning. The California Highway Patrol (CHP) reported multiple car accidents and downed trees due to same adverse weather event. Probability of Future Occurrences Highly Likely – Thunderstorms that produce heavy rain with the potential for hail to develop are well- documented seasonal occurrences that will continue to occur annually in the San Luis Obispo planning area. Climate Change Considerations As average temperatures increase over time, this generally will result in higher extreme temperatures and more warming in the atmosphere can trigger climate changes, which could result in more frequent extreme weather events. According to California’s Fourth Climate Change Assessment, Central Coast Region Report (2018), the number of days each year on which the atmospheric rivers bring “extreme” amounts of rain and snow to the region are expected to increase under the projected climate change for the state, possibly increasing more than a quarter. Pacific Northwest National Laboratory researchers have also found that atmospheric rivers will reach the West Coast more frequently (Gao, 2015). Currently, the West receives rain or snow from these atmospheric rivers between 25 and 40 days each year. By the end of this century, days on which the atmospheric rivers reach the coast could increase by a third this century, between 35 and 55 days a year. According to the climate change analysis completed for the 2014 San Luis Obispo County Integrated Regional Water Management Plan precipitation is projected to increase in winter months while decreasing in the spring months, with the greatest change expected to take place in the North County Coastal Area. Decreases in precipitation in spring months will also have an impact on runoff which may have an impact on water supply sources, refer to the Drought section for more information on water supply vulnerability; while the projected increases in precipitation in the spring months will also increase the county’s risk to flooding in some areas, refer to the Flood section for more information in flooding risk and vulnerability. The Fourth Climate Change Assessment for the Central Coast region projects an increase of 3 to 10 inches across the five counties in the central coast. Vulnerability: Thunderstorm/Heavy Rain/Dense Fog/Freeze General Property The San Luis Obispo County Planning Area experiences a rainy season in the winter months through early spring. These winter storms can include significant precipitation as well as high winds, and hail. The primary effect of these storms has not resulted in significant injury or damages to people and property, or the losses are typically covered by insurance. It is the secondary hazards caused by weather, such as floods, that have had the greatest impact on the County. Damage and disaster declarations related to adverse weather have occurred and will continue to occur in the future. Heavy rain and thunderstorms are the most frequent type of severe weather occurrences in the County. Utility outages, downing of trees, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-51 debris blocking streets and damage to property can be a direct result of these storm events. Given the nature of these types of storms, the entire County is potentially at risk. People Exposure is the greatest danger to people from severe thunderstorms. People can be hit by lightning, pelted by hail, and caught in rising waters. Serious injury and loss of human life is rarely associated with hailstorms. Reduced visibility is the greatest risk to people when heavy fog is prevalent. Particularly when fog is dense, it can be hazardous to drivers, mariners and aviators and contributes to numerous accidents each year. To reduce injury and harm, people should avoid driving when dense fog is prevalent, if possible. If driving is pertinent, emergency services advise driving with lights on low beam, avoiding stopping on highways, and avoiding crossing traffic lanes. Aspects of the population who rely on constant, uninterrupted electrical supplies may have a greater, indirect vulnerability to lightning. As a group, the elderly or disabled, especially those with home health care services relying on rely heavily on an uninterrupted source of electricity. Resident populations in nursing homes, residential facilities, or other special needs housing may also be vulnerable if electrical outages are prolonged. If they do not have a back-up power source, rural residents and agricultural operations reliant on electricity for heating, cooling, and water supplies are also especially vulnerable to power outages. Social Vulnerability Outdoor laborers are particularly at risk to thunderstorms and the association hazards of precipitation, hail and the increased risk of being struck by lightning. Based on the SoVI data presented and discussed in subsection 4.4.1, the communities located in north county San Luis Obispo such as Paso Robles, San Miguel and Atascadero and in south county such as Oceano and Nipomo, where many agricultural activities take place are also among the areas of the county with the highest ranking overall social vulnerability. Critical Facilities and Infrastructure Because of the unpredictability of severe thunderstorm and a tornado event strength and path, most critical infrastructure that is above ground is equally exposed to the storm’s impacts. Due to the random nature of these hazards, a more specific risk assessment was not conducted for this plan. Economy Economic impact of a severe thunderstorm is typically short term. Lightning can cause power outages and fires. Hail can destroy exposed property; an example is car lots, where entire inventories can be damaged. Generally, long-term economic impacts center more around hazards that cascade from a severe thunderstorm, including wildfires ignited by lightning, and flooding (refer to the Flood section). In general, all adverse weather poses a risk to agriculture economy in the county. Table 5-19 below describes the crops losses related to adverse weather events and associated indemnity amounts or loss payments from the United States Department of Agriculture (USDA), Risk Management Agency in the past three years. Heat, frost/freeze, and high wind/excess wind events have been the cause of the majority of crop losses related to weather since 2015. Overall, in the past three years there have been 200 adverse ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-52 weather events that have led to crop losses in the county, totaling in over $20 million in loss payments due to adverse weather. Table 5-19 San Luis Obispo County Crop Losses and Loss Payments, 2015-2018 Cause of Loss Number of Events Indemnity Amounts (loss payments) Frost/Freeze 45 $6,713,314 Cold Winter 5 $43,037 Excess Moisture/Cold Wet Weather 47 $6,457,335 Hail 3 $36,272 Heat 64 $3,569,208 Wind/Excess Wind 33 $3,133,818 Other 3 $51,683 Totals 200 $20,004,667 Source: USDA Risk Management Agency, https://www.rma.usda.gov/SummaryOfBusiness/CauseOfLoss Historic, Cultural, and Natural Resources Severe thunderstorms are a natural environmental process. Environmental impacts include the sparking of potentially destructive wildfires by lightning and localized flattening of plants by hail. As a natural process, the impacts of most severe thunderstorms by themselves are part of the overall natural cycle and do not cause long-term consequential damage. Future Development New critical facilities, such as communication towers should be built to withstand heavy rain, wind, and hail damage. Future development projects should consider adverse weather hazards at the planning, engineering and architectural design stage with the goal of reducing vulnerability. Stormwater master planning and site review should account for buildings to withstand adverse weather events considered for all new development. Thus, development trends in the County are not expected to increase overall vulnerability to the hazard but all development will be affected by adverse weather and storm events and population growth will increase potential exposure to hazards such as thunderstorms and dense fog. Risk Summary - Thunderstorm/Heavy Rain/Dense Fog/Freeze • The overall impact to the community from severe weather events associated with heavy rain, thunderstorms, hail, and fog could include: • San Luis Obispo County has experienced 21 hail, heavy rain, and frost/freeze events in past 68 years • Average annual precipitation ranges from 22.4 inches to 15.2 inches depending on the area of the County • Since 2015 over $20 million in loss payments from USDA related to crop losses from adverse weather events have been paid. • Related hazards: Flood, Wildfire, Landslide and Debris Flow, Coastal Storm/Coastal Erosion/Sea Level Rise, Agriculture/Pest Infestation/Plant Disease/Tree Mortality ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-53 Table 5-20 Hazard Risk Summary - Thunderstorm/Heavy Rain/Dense Fog/Freeze Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Significant Likely Negligible Medium City of Arroyo Grande Significant Likely Limited Low City of Atascadero Significant Likely Limited Low City of Grover Beach Significant Likely Limited Low City of Morro Bay Extensive Highly Likely Limited High City of Paso Robles Significant Highly Likely Limited High City of Pismo Beach Significant Likely Limited Low City of San Luis Obispo Extensive Likely Limited Medium Avila Beach CSD Significant Occasional Negligible Medium Ground Squirrel Hollow CSD Limited Likely Negligible Medium Heritage Ranch CSD Extensive Highly Likely Critical High Los Osos CSD Significant Likely Limited Medium Nipomo CSD Limited Likely Negligible Low San Miguel CSD Extensive Likely Catastrophic High San Simeon CSD Likely Significant Limited Low Templeton CSD Significant Highly Likely Limited High Cayucos Sanitary District Extensive Likely Critical High Port San Luis Harbor District Extensive Highly Likely Limited Medium San Luis Obispo FCWCD Significant Highly Likely Negligible Low South San Luis Obispo Sanitary District Significant Likely Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-54 5.3.3 Adverse Weather: High Wind/Tornado Hazard/Problem Description High winds, often accompanying severe thunderstorms, can cause significant property and crop damage, threaten public safety, and have adverse economic impacts from business closures and power loss. Windstorms in San Luis Obispo County are typically straight-line winds. Straight-line winds are generally any thunderstorm wind that is not associated with rotation (i.e., is not a tornado). It is these winds, which can exceed 100 mph, that represent the most common type of severe weather and are responsible for most wind damage related to thunderstorms. These winds can overturn mobile homes, tear roofs off houses, topple trees, snap power lines, shatter windows, and sandblast paint from cars. Other associated hazards include utility outages, arcing power lines, debris blocking streets, dust storms, and an occasional structure fire. Tornadoes are another severe weather hazard that can affect the San Luis Obispo County planning area. Tornadoes form when cool, dry air sits on top of warm, moist air. Tornadoes are rotating columns of air marked by a funnel-shaped downward extension of a cumulonimbus cloud whirling at destructive speeds of up to 300 mph, usually accompanying a thunderstorm. Tornadoes are the most powerful storms that exist. They can have the same pressure differential that fuels 300-mile-wide hurricanes across a path only 300-yards wide or less. Figure 5-14 illustrates the potential impact and damage from a tornado. Figure 5-14 Potential Impact and Damage from a Tornado Source: FEMA: Building Performance Assessment: Oklahoma and Kansas Tornadoes Prior to February 1, 2007, tornado intensity was measured by the Fujita (F) scale. This scale was revised and is now the Enhanced Fujita scale. Both scales are sets of wind estimates (not measurements) based on damage. The new scale provides more damage indicators (28) and associated degrees of damage, allowing for more detailed analysis and better correlation between damage and wind speed. It is also more precise because it takes into account the materials affected and the construction of structures ••• Potential Impact and Damage From a Tornado □ □ □ □ Mlllll dlurlllp lu rods anti bnJkatl IW'ldlMs OCCUf,LJi,v.a'ldt-rarab1KbbaD!w ~ Mn:wdarn9 Kl n.■nd ~ can b& OCHNM Roots 111etllm8IQ«l. indulftiOlll.tlOnot~.1nc1 :1Mie ~-~nrdhomn,.unfllll'Vil!rfliln«II lowdilloN: e11tbtVitledollu,,e,il~ .. Trt!Mancl ~eiu.~o,a,el)lor,l,,f\ o,,,er,Medum'l5Fl!'ddebt!ll>eoolne1 tllbome. ~ olhef a;ll'\ICl,i,r,tL Roor•IWIOsornew.dlt. ~~IO!w<I rM1011ry,G1C1tomfromS1n.QJ1113&NII encllle,yllUi!lcingta,•ol'bwt~ Ma,uflQINHI hlJffl9S tJn~ ~1;11111';111~~$omlJl1"1J~~ ~\14-~«lhOin'ott,,0$ ..... , ~'1tPO'fO"J,~W!T1US1'UCW1W/ll'tllMG Aut~_, dillJlu a llbpbU:a:I aoo att.1 lllr!ClimL Tr.-■ra 011.-. upoallld lf\dlliGWlt(IIW!f. S~ frlllM 1-K:i!Dili ~~'ffl:d ~.imirilt-clfnimtt'N!lr~o. ataligrilicanllydamilg!!dcrdll!llla,,ed ~•ornalllHIMdOIM!J l!-fl,o,,ed ~ cb18AOl!IS. 1tflM al'II l4)f'OOt8d and ;iptllwed. Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-55 damaged by a tornado. Table 5-21 shows the wind speeds associated with the original Fujita scale ratings and the damage that could result at different levels of intensity. Table 5-22 shows the wind speeds associated with the Enhanced Fujita Scale ratings. The Enhanced Fujita Scale’s damage indicators and degrees of damage can be found online at www.spc.noaa.gov/efscale/ef-scale.html. Table 5-21 Original Fujita Scale Fujita (F) Scale Fujita Scale Wind Estimate (mph) Typical Damage F0 < 73 Light damage. Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged. F1 73-112 Moderate damage. Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off roads. F2 113-157 Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground. F3 158-206 Severe damage. Roofs and some walls torn off well- constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown. F4 207-260 Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown, and large missiles generated. F5 261-318 Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters (109 yards); trees debarked; incredible phenomena will occur. Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/f-scale.html Table 5-22 Enhanced Fujita Scale Enhanced Fujita (EF) Scale Enhanced Fujita Scale Wind Estimate (mph) Potential Damage EF0 65-85 Minor damage. Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over. Confirmed tornadoes with no reported damage (i.e., those that remain in open fields) are always rated EF0. EF1 86-110 Moderate damage. Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken. EF2 111-135 Considerable damage. Roofs torn off from well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light- object missiles generated; cars lifted off ground. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-56 Enhanced Fujita (EF) Scale Enhanced Fujita Scale Wind Estimate (mph) Potential Damage EF3 136-165 Severe damage. Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations are badly damaged. EF4 166-200 Devastating damage. Well-constructed and whole frame houses completely leveled; cars and other large objects thrown, and small missiles generated. EF5 Over 200 Incredible damage. Strong-framed, well-built houses leveled off foundations are swept away; steel-reinforced concrete structures are critically damaged; tall buildings collapse or have severe structural deformations; some cars, trucks, and train cars can be thrown approximately 1 mile (1.6 km). Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/ef-scale.html Table 5-23 below outlines the Beaufort scale, which describes the damaging effects of wind speed. Table 5-23 Beaufort Wind Scale Wind Speed (mph) Description – Visible Condition 0 Calm; smoke rises vertically 1-4 Light air; direction of wind shown by smoke but not by wind vanes 4-7 Light breeze; wind felt on face; leaves rustle; ordinary wind vane moved by wind 8-12 Gentle breeze; leaves and small twigs in constant motion; wind extends light flag 13-18 Moderate breeze; raises dust and loose paper; small branches are moved 19-24 Fresh breeze; small trees in leaf begin to sway; crested wavelets form on inland water 25-31 Strong breeze; large branches in motion; telephone wires whistle; umbrellas used with difficulty 32-38 Moderate gale whole trees in motion; inconvenience in walking against wind 39-46 Fresh gale breaks twigs off trees; generally, impedes progress 47-54 Strong gale slight structural damage occurs; chimney pots and slates removed 55-63 Whole gale trees uprooted; considerable structural damage occurs 64-72 Storm very rarely experienced; accompanied by widespread damage 73+ Hurricane devastation occurs Source: NWS ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-57 High winds and tornadoes can cause damage to property and loss of life. While most tornado damage is caused by violent winds, most injuries and deaths result from flying debris. Property damage can include damage to buildings, fallen trees and power lines, broken gas lines, broken sewer and water mains, and the outbreak of fires. Agricultural crops and industries may also be damaged or destroyed. Access roads and streets may be blocked by debris, delaying necessary emergency response. Geographic Area Wind and tornadoes have the potential to happen anywhere in the County. The resulting damage from wind and tornado events may be most severe in the downtown areas of incorporate communities where there are more large trees, infrastructure, and higher density development. Extent Based on NCEI records between 1950 and 2018 there have been a combined 31 high wind/thunderstorm winds (27 events) and four tornado/funnel cloud events in San Luis Obispo County which has resulted in a total of $4,050,000 in property damage. The most damaging event took place on January 2, 2006 and was a 56-mph wind event that resulted in $4,000,000 in property damages. Overall, high wind event impacts would likely be limited, with a majority of impacts being related to property damages caused my downed trees as well as power outages. In the past 68 years all the tornado events that have taken place in San Luis Obispo County have been F0 tornadoes. However, it should be noted that, although unlikely, larger tornadoes could occur. Should the County be hit by an EF-3 or higher tornado, it can be extrapolated that because of its relative size and the potential size and length of a tornado’s path a significant portion of the County could be impacted, resulting in property and crop damage and loss of life. Tornado impacts to the County would likely be negligible, with less than 10 percent of the planning area affected by events in the EF0-2 range, though stronger tornadoes are possible. The impact to quality of life or critical facilities and functions in the affected area would depend on where the tornado occurred. Injuries or deaths are possible due to wind thrown trees or property damage caused by wind events. Overall, impacts from high wind and tornado events would likely be negligible, with less than 10 percent of property severely damaged and shutdown of facilities due to loss of power for 24 hours or less. Previous Occurrences During the rainy season, the San Luis Obispo planning area is prone to relatively strong thunderstorms, sometimes accompanied by high winds and tornadoes. While tornadoes do occur occasionally, most often they are of F0 intensity. The NCEI Storm Events Database does not record any F1, F2, or F3 events that have occurred in the planning area in the past. Documented incidents of high wind/thunderstorm winds and tornado/funnel cloud events in San Luis Obispo from the NCEI Database are listed in the following tables. Table 5-25 Past High Wind and Tornado Events contains incident descriptions for significant historic events. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-58 Table 5-24 San Luis Obispo County High Wind Events Date Magnitude (mph) Property Damage February 18, 1993 - $50,000 November 26, 1997 62 0 February 2, 1998 78 0 February 5, 1998 61 0 February 7, 1998 61 0 February 19, 1998 50 0 April 3, 1999 55 0 February 11, 2000 52 0 December 17, 2000 48 0 January 10, 2001 55 0 March 4, 2001 65 0 November 24, 2001 55 0 December 7, 2001 52 0 December 19, 2002 55 0 February 25, 2004 47 0 January 7, 2005 58 0 January 2, 2006 56 $4,000,000 December 7, 2007 51 0 January 4, 2008 65 0 January 27, 2008 54 0 February 23, 2008 65 0 October 13,2009 68 0 December 13, 2009 50 0 January 18, 2010 52 0 January 20, 2010 52 0 December 11, 2014 50 0 Total $4,050,00 Source: NCEI Storm Events Database *NOTE no reports of crop damages, deaths or injuries were recorded ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-59 Table 5-25 Past High Wind and Tornado Events Date of Event Incident Description November 26, 1997 A line of severe thunderstorms rumbled across San Luis Obispo and Santa Barbara counties. The storms produced winds gusting up to 71 mph and heavy rain. February 2, 1998 Hearst Castle, in San Luis Obispo county, reported winds gusting to 90 mph. Elsewhere, winds gusting in excess of 70 mph were reported. Hundreds of trees and power lines were blown down, resulting in numerous power outages. Along with the strong winds, heavy rain drenched the entire area. (refer to Table 5-4 for details on the rain event). February 19, 1998 Strong thunderstorms moving across San Luis Obispo county produced strong winds in the Templeton area. A spotter reported winds gusting to 58 mph. May 5, 1998 A small tornado developed over the City of San Luis Obispo. The tornado knocked out power to several hundred homes. Also, four homes were damaged, including a home struck by a fallen cypress tree. (F0) February 11, 2000 A powerful cold front brought strong winds and heavy snow to parts of Central and Southern California. In Morro Bay, southeast winds, gusting to 60 mph ahead of the front, knocked down numerous trees and power lines. December 17, 2000 Gusty offshore winds buffeted coastal sections of San Luis Obispo county. In the City of San Luis Obispo, the winds blew out the windows in an unoccupied mobile home, as well as destroyed part of a car port. In Nipomo, a weather spotter reported sustained winds of 35 mph with gusts to 55 mph. Also, the strong winds produced widespread power outages. January 10, 2001 A strong thunderstorm produced damaging winds in northern San Luis Obispo County. Across southern sections of Atascadero, trees were uprooted as well as damage to fences and decks. March 4, 2001 Across Central and Southern California, strong southeasterly winds accompanied the storm. Widespread winds between 30 and 50 MPH with stronger gusts were reported from the coastal areas to the mountains. (Refer to Table 5-4 for more details on the heavy rain and flooding that accompanied this event) November 24, 2001 A strong cold front moved though San Luis Obispo County, producing strong and gusty winds. Weather spotters and the Morro Bay Fire Department reported sustained winds between 35 and 45 mph with gusts as high as 62 mph. Numerous small trees and power lines were blown down between Morro Bay and Atascadero. December 7, 2001 Gusty northeast winds knocked down power lines and small trees in the community of Morro Bay. Wind speeds were estimated between 25 and 35 mph with local gusts as high as 60 mph. February 2, 2004 A waterspout, which developed offshore of Oceano Dunes, came onshore as a weak tornado. The weak tornado hit a park ranger in his truck. Fortunately, the park ranger was not injured, and his truck sustained no reportable damage. January 2, 2006 Strong west to northwest winds, gusting to 65 MPH, affected the community of Cambria in San Luis Obispo County. In total, 84 homes sustained damage with 31 homes sustaining major damage. Estimates of property damage were around $4 million. January 4, 2008 In early January, a powerful Pacific storm brought strong winds, heavy rainfall, flash flooding and winter storm conditions to Central and Southern California. The strongest winds were reported across San Luis Obispo and Santa Barbara counties as well as all mountain areas. The winds knocked down trees and power lines, producing numerous power outages. An automated sensor in Atascadero reported sustained winds of 43 mph. A weather spotter in Morro Bay reported a southeasterly wind gust of 75 mph. January 27, 2008 An observer at Hearst Castle reported southeast winds gusting to 62 mph. The last of several January storms brought high winds and heavy snow to sections of Central and Southern ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-60 Date of Event Incident Description California. Across San Luis Obispo and Santa Barbara counties, strong southeasterly winds gusting to 65 mph knocked down trees and power lines across the area. February 23, 2008 An automated sensor at Atascadero reported southeast winds gusting to 59 mph. An automated sensor at Point Arguello reported southeast winds gusting to 63 mph. In the nearby community of Cambria, numerous trees and power lines were knocked down by the winds. Strong southeast winds gusting to 75 mph were reported in the mountains of San Luis Obispo county. A powerful cold front moved across Central and Southern California in late February. Although the front did not produce significant rainfall, it did bring strong and gusty southeasterly winds to the area. Wind gusts as high as 75 to 86 mph were reported in some areas. The strongest and most widespread winds occurred across the Central Coast as well as the mountains. Numerous trees and power lines were knocked down. October 13, 2009 From October 12th through October 14th, the first significant storm of the season moved through Southern California. The storm brought heavy rainfall and very gusty southerly winds to the area. Rainfall totals were very impressive, generally ranging between 1 and 3 inches over coastal areas to between 4 and 10 inches in the mountains. Some isolated areas received rainfall amounts over 10 inches over San Luis Obispo and Santa Barbara counties. This storm brought very strong and gusty southerly winds to the area with warning-level winds reported in many areas. December 13, 2009 A trained weather spotter reported a wind gust of 58 MPH associated with a severe thunderstorm. A powerful winter storm brought heavy rain, flash flooding, gusty winds and severe thunderstorms to Central and Southern California. Rainfall amounts for this storm ranged from 1 to 3 inches over coastal areas to between 3 and 6 inches in the mountain and foothill areas. With such heavy rainfall, there were several reports of flash flooding along with mud and debris flows near the Station Fire burn area. In San Luis Obispo County, a severe thunderstorm producing very strong winds. January 18, 2010 Strong and gusty south winds associated with an approaching winter storm affected the coast of San Luis Obispo County. A weather spotter in Grover Beach reported south winds gusting to 60 MPH. A series of powerful winter storms affected Central and Southern California between the 18th and 22nd of January. As this series of storms moved across the area, they brought heavy rain, flash flooding, gusty winds, heavy snow and even severe weather to the area. January 20, 2010 Strong and gusty south winds associated with an approaching winter storm affected the interior valleys of San Luis Obispo county. The Carrizo RAWS sensor reported south winds gusting to 60 MPH while the ASOS at Paso Robles reported sustained south winds of 40 MPH. A trained spotter in the Grover Beach area reported a thunderstorm wind gust of 58 MPH. February 13 – 14, 2019 February 2019 brought heavy rain and high wind throughout the County. These events resulted in downed power lines and trees. The National Weather Service issued a wind advisory which lasted from February 13th – 14th. On February 13th, 2019, high winds lead to 2,000 PG&E customers to lose power and downed power lines in Arroyo Grande causes roads to be closed. The Atascadero Fire Department reported a 50-foot pine tree fell on two single- story multi-family residences leading to eight people being displaced but none were injured. The fallen tree led to $400,000 in property damage due to a broken water line (San Luis Obispo Tribune, 2019). Source: NCEI Storm Events Database, 2014 San Luis Obispo LHMP The following figures spatially depict the past high wind and tornado events that described in the table above and that have occurred in San Luis Obispo County since 1950. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-61 Figure 5-15 San Luis Obispo County Wind Events 1955 – 2017 PAC IFIC OC EAN ---Waterways -+--+ D ••• Lakes Wi nd Events (1955 -2017) Railroads Magnitude (mph/type) Hi ghway -n/a Freeway ~ 55-63 I Storm Cit ies ~ 64-73 I Violent Storm Co unt ies -~ 7 41 Hurricane Force Map compiled 2/2019; in ten ded for pla nning purposes on ly. Data Sou rce : Sa n Luis Ob ispo Co unty, US Census TI GER Database , CA Open Data Porta l, NOAA Storm Database I! Monterey I Kings i Tula re . . 1/ ----------------------~----- Santa Ba rba ra 0 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-62 Figure 5-16 San Luis Obispo County Tornado Events 1950 -2017 Monterey Kings ~~b_~~~,==;"-===~~1.-~~~~-\-· ________ _ PACIFIC OCEAN --waterways -+--+ D ••• Lakes Railroads Tornado Events (1950 -2017) Highway Mag n itude (F Scale) Freeway -n/a Cities c==:::) Co unties c==:::) 2 Map compiled 2/2019; intended for plann ing purposes on ly. Data Source : San Luis Obispo County, US Census TIGER Database , CA Open Data Portal , NOAA Sto rm Database Santa Barbara 0 10 20 40 Miles ' IO I I I ! 1_ - Tu lare N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-63 Likelihood of Future Occurrences Likely—Thirty-one high wind and tornado events have occurred in San Luis Obispo County over 68 years of record keeping, which equates to one high wind or tornado event every 2.2 years, on average, and a 46 percent chance of a high wind or tornado event occurring in any given year. Historical wind activity within the planning area indicates that the area will likely continue to experience high wind during thunderstorm events with a potential of the formation of funnel clouds and low intensity tornadoes during adverse weather conditions. The actual risk to the County is dependent on the nature and location of any given thunderstorm or tornado event. Climate Change Considerations There presently is not enough data or research to quantify the magnitude of change that climate change may have related to tornado frequency and intensity. NASA’s Earth Observatory has conducted studies which aim to understand the interaction between climate change and tornadoes. Based on these studies meteorologists are unsure why some thunderstorms generate tornadoes and others don’t, beyond knowing that they require a certain type of wind shear. Tornadoes spawn from approximately one percent of thunderstorms, usually supercell thunderstorms that are in a wind shear environment that promotes rotation. Some studies show a potential for a decrease in wind shear in mid-latitude areas. Because of uncertainty with the influence of climate change on tornadoes, future updates to the mitigation plan should include the latest research on how the tornado hazard frequency and severity could change. The level of significance of this hazard should be revisited over time. Vulnerability to Severe Weather: High Wind and Tornadoes Property General damages are both direct (what the wind event physically destroys) and indirect, which focuses on additional costs, damages and losses attributed to secondary hazards spawned by the event, or due to the damages caused by the wind event. Depending on the magnitude of the wind events as well as the size of the tornado and its path, a tornado is capable of damaging and eventually destroying almost anything. Construction practices and building codes can help maximize the resistance of the structures to damage. Secondary impacts of damage caused by wind events often result from damage to infrastructure. Downed power and communications transmission lines, coupled with disruptions to transportation, create difficulties in reporting and responding to emergencies. These indirect impacts of a wind event put tremendous strain on a community. In the immediate aftermath, the focus is on emergency services. Downed trees caused by a wind event are a common occurrence in the county (refer to Table 5-25). Falling trees can cause significant damage to property and put people at risk. Due to multiple years of drought in the county, combined with tree disease and pests, (refer to the Drought section and the section on Agricultural Pest Infestation, Plant Disease, Marine Invasive Species and Tree Mortality), many trees in the area have been impacted making them more susceptible to blow-down during wind events. GIS was used to estimate the potential for wind damage from fallen trees, assuming that tree mortality areas will be most susceptible. Tree mortality composes just over 13% of the county in area and are found to intersect with a total of 35,780 properties across the county, based on the property centroids defined for all the hazards’ parcel analyses. The western half of county is most impacted by tree mortality, with the areas most affected being North County Inland and South County Areas. The following table summarizes ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-64 the number of properties in each jurisdiction found within tree mortality high hazard zones (both Tier 1 and 2) based on GIS overlay analysis. Refer to each jurisdictions annex for more details on the types of properties within tree mortality high hazard zones. Additional analysis related to critical facilities and tree mortality high hazard zones is discussed further below. Table 5-26 Properties Within Tree Mortality High Hazard Zones, by Type and Jurisdiction Jurisdiction Property Count Improved Value Arroyo Grande 3,253 $825,279,845 Atascadero 57 $14,895,750 City of San Luis Obispo 11 $2,804,138 Grover Beach 4,713 $866,176,076 Paso Robles 10,306 $2,556,604,120 Pismo Beach 4,293 $1,290,261,821 Unincorporated 13,147 $3,508,212,028 TOTAL 35,780 $9,064,233,778 Source: CalFire FRAP, 2019; Wood GIS analysis People Community members are the most vulnerable to high wind and tornado events. The availability of sheltered locations such as basements, buildings constructed using tornado-resistant materials and methods, and public storm shelters, all reduce the exposure of the population. However, there are also segments of the population that are especially exposed to the indirect impacts of high winds and tornadoes, particularly the loss of electrical power. These populations include the elderly or disabled, especially those with medical needs and treatments dependent on electricity. Nursing homes, community- based residential facilities, and other special needs housing facilities are also vulnerable if electrical outages are prolonged, since backup power generally operates only minimal functions for a short period of time. Social Vulnerability Communities that are vulnerable to the impacts of a high wind or tornado event are the same areas of the county with the highest-ranking vulnerable household compositions and overall high ranking of social vulnerability such as Paso Robles and Grover Beach. Based on the SoVI data presented in and discussed in subsection 4.4.1, mitigation efforts to address vulnerability to high wind and tornado should be focused on the communities with the highest social vulnerability rankings. Critical Facilities and Transportation Infrastructure Public gathering places including (but not limited to) schools, community centers, shelters, nursing homes and churches, may have increased impacts at certain times of day if struck by a tornado. Other critical and essential facilities, transportation and utility lifelines, and high potential loss facilities such as power plants could also be significantly affected by powerful wind or tornado events, particularly in areas impacted by tree mortality. In the following two tables summarizing critical facilities, GIS overlay analysis was performed to find which of these facilities fall within the high tree mortality areas. Table 5-15 summarizes the facilities found in tree mortality hazard zones by type, while Table 5-16 summarizes the total facilities in these tree mortality areas by jurisdiction. According to this analysis, most critical facilities found at risk are in the unincorporated portions of county, with 47 in Paso Robles and 13 or fewer in Pismo Beach, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-65 Grover Beach, and Arroyo Grande. The three most common facility types at risk are microwave service towers, public schools, and day care facilities. Most of the critical facilities are found in Tier 2 tree mortality areas (190), though 5 facilities are in Tier 1 tree mortality areas. Table 5-27 Critical Facilities Within Tree Mortality Hazard Zones, by Facility Type Critical Facility Type Critical Facility Count Airports 3 AM Transmission Towers 1 Cellular Towers 4 Colleges / Universities 1 Day Care Facilities 21 Emergency Medical Service Stations 12 Energy Commission Facilities 4 Fire Stations 12 FM Transmission Towers 11 Hospitals 1 Local Law Enforcement 5 Microwave Service Towers 68 Nursing Homes 5 Paging Transmission Towers 1 Power Plant 1 Private Schools 7 Public Schools 26 TV Analog Station Transmitters 3 Urgent Care 3 Water Treatment Facilities 3 Wastewater Treatment Plants 3 Airports 3 TOTAL 195 Source: CalFire FRAP, 2019; HIFLD, San Luis Obispo Planning & Building/GIS Dept., San Luis Obispo County Community Services Districts; Wood GIS analysis Table 5-28 Critical Facilities Within Tree Mortality Hazard Zones, by Jurisdiction Jurisdiction Critical Facility Count Arroyo Grande 10 Grover Beach 12 Paso Robles 47 Pismo Beach 13 Unincorporated 113 TOTAL 195 Source: CalFire FRAP, 2019; HIFLD, San Luis Obispo Planning & Building/GIS Dept., San Luis Obispo County Community Services Districts; Wood GIS analysis Historic, Cultural, and Natural Resources High winds and tornadoes can cause massive damage to the natural environment, uprooting trees and other debris. This is part of a natural process, however, and the environment will return to its original state in time. GIS was used to estimate the potential for wind damage to historic properties from fallen trees, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-66 assuming that tree mortality areas will be most susceptible. The analysis indicates that a total of thirty- three (33) historic properties in San Luis Obispo County are located in high hazard tree mortality zone, five (5) are located in a Tier 1 zone and twenty-eight (28) are located in a Tier 2 hazard zone. Details on the specific properties at risk are found in Appendix E. Economy Winds typically don’t have long-term impacts on the economy, although wind does have an impact on the agriculture economy in the county. As shown in Table 5-19, wind events have been a leading cause of crop loss in the past three years (2015-2018), resulting in over $3 million in loss payments from the USDA. Both winds and tornadoes may impact exposed critical infrastructure such as power lines; depending on the impact and the function, this could cause a short-term economic disruption. The most common problems associated with tornadoes and high winds are loss of utilities. Downed power lines can cause power outages, leaving large parts of the county isolated, and without electricity, water, and communication. Damage may also limit timely emergency response and the number of evacuation routes. Downed electrical lines following a storm can also increase the potential for lethal electrical shock. Damaging winds can also cause wildfires, refer to the Wildfire section for more information on the county’s vulnerability to wildfires. Future Development As the County continues increase in population, the number of people and housing developments exposed to the hazard increases. Adherence to current building codes, coupled with proper education on building techniques and the use of sturdy building materials, attached foundations, and other structural techniques may minimize the property vulnerabilities. Public shelters at parks and open spaces may help reduce the impacts of tornadoes and high wind events on the recreational populations exposed to storms. Risk Summary – High Wind and Tornadoes The overall impact to the community from tornadoes and wind due to severe storms could include: • San Luis Obispo has experienced 31 wind events in the past 68 years; • Most damaging wind event occurred on 1/2/2006 and resulted in $4,000,000 in property damages; • Over $3 million in crop indemnities have been paid due to crop loss from excessive wind; • Related hazards: Wildfire, Coastal Storm/Coastal Erosion/Sea Level Rise, Agriculture/Pest Infestation/Plant Disease/Tree Mortality ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-67 Table 5-29 Hazard Risk Summary – High Wind and Tornadoes Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Significant Likely Negligible Low City of Arroyo Grande Significant Likely Negligible Low City of Atascadero Extensive Likely Limited Low City of Grover Beach Significant Likely Negligible Low City of Morro Bay Significant Highly Likely Limited Medium City of Paso Robles Significant Highly Likely Limited High City of Pismo Beach Significant Likely Limited Low City of San Luis Obispo Extensive Occasional Limited Medium Avila Beach CSD Significant Occasional Negligible Medium Ground Squirrel Hollow CSD Limited Likely Negligible Medium Heritage Ranch CSD Extensive Highly Likely Critical High Los Osos CSD Significant Likely Limited Medium Nipomo CSD Limited Likely Negligible Low San Miguel CSD Extensive Likely Catastrophic High San Simeon CSD Significant Likely Limited Low Templeton CSD Significant Highly Likely Limited High Cayucos Sanitary District Extensive Likely Critical High Port San Luis Harbor District Extensive Highly Likely Limited Medium San Luis Obispo FCWCD Limited Highly Likely Negligible Low South San Luis Obispo Sanitary District Significant Likely Negligible Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-68 5.3.4 Adverse Weather: Extreme Heat Hazard/Problem Definition Extreme heat events can have severe impacts on human health and mortality, natural ecosystems, the agriculture sector and other economic sectors. According to information provided by FEMA, extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks. Heat kills by taxing the human body beyond its abilities, usually from heat stroke. In a normal year, about 175 Americans succumb to the demands of summer heat. According to the National Weather Service (NWS), among natural hazards, only the cold of winter—not lightning, hurricanes, tornadoes, floods, or earthquakes—takes a greater toll. As a comparison, in the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the heat wave of 1980, more than 1,250 people died. The 2018 California State Hazard Mitigation Plan (SHMP) notes the 2006 heat wave lead to 650 deaths in a 13-day period (Cal OES 2018) and in the past 15 years heat waves have claimed more lives in California than all other declared disaster events combined (California Climate Adaptation Strategy 2018). Heat disorders generally have to do with a reduction or collapse of the body’s ability to shed heat by circulatory changes and sweating or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body’s inner core begins to rise, and heat-related illness may develop. The elderly, small children, individuals who work outside, patients with chronic medical conditions, those on prescription medication therapy, and people with weight and alcohol problems are particularly susceptible to heat reactions, especially during heat waves in areas where moderate climate usually prevails. Figure 5-17 illustrates the relationship of temperature and humidity to heat disorders. Figure 5-17 National Weather Service Heat Index Source: National Weather Service Note: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous. NWS Heat Index Temperature (°F) 80 82 84 86 88 92 40 80 81 83 85 88 94 45 80 82 84 87 89 96 -81 83 85 88 91 99 0 50 0 ->, 55 81 84 86 89 93 :t:::: 60 82 84 88 91 95 :'2 E 65 82 85 89 93 98 ::, :::c 70 83 86 90 Qj 75 84 88 92 > ::: 80 84 89 94 .!!:! Qj 85 85 90 96 0:: 90 86 91 98 95 86 93 100 100 87 95 103 Likelihood of Heat Disorders with Prolonged Exposure or Strenuous Activity D Caution D Extreme Caution Danger ■ Extreme Danger ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-69 Geographic Area All of San Luis Obispo County is at risk of extreme heat events, although different areas of the county may be more at risk than others. Coastal communities on average have lower temperatures compared to communities in the inland areas of the county and may be less at risk to extreme temperatures although potentially less acclimatized to high temperatures if they occur. The North County inland area has the potential for the highest extreme heat days. Extent (Magnitude/Severity) The NWS has in place a system to initiate alert procedures (advisories, watches, and warnings) when high temperatures are expected to have a significant impact on public safety. The expected severity of the heat determines which type of alert is issued. The “California OES Contingency Plan for Excessive Heat Emergencies” (2014) indicates that through the use of historical weather and mortality data, the NWS and the California Department of Public Health (CDPH) have identified five major types of climate regions within California to account for climate differences among regions in order to recognize what constitutes an excessive heat event in each of the regions. When temperatures spike for two or more consecutive days without an adequate drop in nighttime temperature to cool the outdoor and indoor environments, there is a significant increase in the risk to vulnerable populations. Overall, extreme heat impacts would likely be limited in the planning area, with the inland portions of the planning area being most affected. Extreme heat will have an impact on vulnerable populations as well as impact the agricultural sector if the event occurs during certain times of the year. Previous Occurrences Information from the four representative weather stations introduced in subsection 5.3.1 Adverse Weather: General is summarized below and in Figure 5-18 through Figure 5-21 City of San Luis Obispo Area - San Luis Obispo Polytech (Period of Record 1893 to 2012) The monthly average maximum temperatures in the warmest months (June through October) range from the low-70s to the mid-70s. Monthly average minimum temperatures from November through May range from the low to high 40s. The highest recorded daily extreme was 112°F on September 14, 1971. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-70 Figure 5-18 San Luis Obispo Poly Tech Daily Temperature Averages and Extremes (Period of Record 1893 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ North County Coastal Area - Morro Bay Fire Department Weather Station (Period of Record 1959 to 2012) The monthly average maximum temperatures in the warmest months (July through November) range from the mid-60s to the high-60s. Monthly average minimum temperatures from November through June range from the low- to mid-60s. The highest recorded daily extreme was 102°F on September 8, 1984. ..... LI.. ..... Ii) '-::, ~ ~ '-Ii) Cl. I: Ii) ~ ••• SAN LUIS OBISPO POLYTECH, CALIFORNIA (047851) 120 110 100 '30 80 70 60 .. 50 40 30 20 10 Jan 1 ( Period of Record: 02/01/1893 to 06/10/2016 Mar 1 Feb 1 Ma!:! 1 Jul 1 Sep 1 Nov 1 Apr 1 Jun 1 Aug 1 Oct 1 Day of Year Dec 31 Dec 1 Extreme Max --Ave Max -Ave Min Extreme Min] Me:=-::te:rn Re:9ional CliMate: Ce:nte:r Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-71 Figure 5-19 North County Coastal Area - Daily Temperature Averages and Extremes (Period of Record 1959 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ North County Inland Area - Paso Robles Weather Station (Period of Record 1894 to 2012) The monthly average maximum temperatures in the warmest months (May through October) range from the high-70s to the low-90s. Monthly average minimum temperatures from October through April range from the low-30s to low-40s. The highest recorded daily extreme was 117°F on August 13, 1933. ,,... LI. ..... Cl) c.. ::, ~ ~ c.. Cl) C>. I: Cl) .... ••• 110 100 90 80 70 &O 50 40 30 20 MORRO BAY FIRE DEPT, CALIFORNIA (045866) Period of Record: 02/01/1959 to 05/3 1/2016 ~ Jan 1 Mar 1 Ma~ 1 Jul 1 Sep 1 Nov 1 Dec 31 Feb 1 Apr 1 JLJn 1 Aug 1 Oct 1 Dec 1 Day of Year ( Extreme Max --Ave Max --Ave Min Extreme Min] Mestel'n Re9ionG1l Clil'll1h Center Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-72 Figure 5-20 North County Inland Area - Daily Temperature Averages and Extremes (Period of Record 1894 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ South County Area – Pismo Beach Weather Station (Period of Record 1949 to 2016) The monthly average maximum temperatures in the warmest months (May through October) range from the high-60s to the low-70s. Monthly average minimum temperatures from October through April range from the high-40s to low-50s. The highest recorded daily extreme was 108°F on August 28, 1962. ..... LI. ..... Q,) c.. :::, +,I It! c.. Q,) Q. s:: Q,) ~ ••• PASO ROBLES, CALIFORNIA (046730) Period of Record: 81/01/1894 to 86/18/2816 120 110 100 go 80 70 &O _ _____.,....,.., ... 50 40 30 20 10 0 Jan 1 ( Mar 1 Feb 1 Ma~ 1 Jul 1 Sep 1 Nov 1 Apr 1 Jun 1 Aug 1 Oct 1 Day of Year Dec 31 Dec 1 Extreme Max --Ave Max --Ave Min Extreme Min] Mc:st.c: n Rc:,gional CliMat.c: Cc:nt.oti- Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-73 Figure 5-21 South County Area - Daily Temperature Averages and Extremes (Period of Record 1949 -2016) Source: Western Regional Climate Center, www.wrcc.dri.edu/ Events of Note According to information obtained from the NCEI Storm Events Database, in the past 68 years (1950- December 2018) there have been 3 heat and excessive heat events in San Luis Obispo County. The following significant events that have occurred within San Luis Obispo County are highlighted below: July 22, 2006 - The combination of high pressure aloft and above-normal relative humidity resulted in an extended period of excessive heat across San Luis Obispo, Santa Barbara, Ventura and Los Angeles counties. At times, heat index values ranged from 100°F to 119°F. According to the Central Coast Region Report of California’s Fourth Climate Change Assessment, during the 2006 California heat wave the state experienced an overall excess number of emergency room (ER) visits and hospitalizations. The Central Coast region (San Luis Obispo, Santa Barbara, Monterey, San Benito, and Santa Cruz) contributed far more to both ER visits (28 percent) and hospitalizations (47 percent) than what would have been expected (18 percent) based on overall state populations. The report attributes the high number of ER visits and hospitalizations on the regions typically cooler climate and residents lack of acclimatization to the extreme heat. September 3, 2007 - The combination of above normal temperatures and relative humidity produced excessive heat conditions across the mountains and valley of San Luis Obispo county. Heat index values between 105°F and 112°F were reported. The heat wave which started at the end of August continued into the first few days of September. The combination of above normal temperatures and relative humidity continued to produce excessive heat conditions across sections of Southern California. ••• 11 100 PISMO BEACH, CALIFORNIA (046943) Period of Record : 07/01/19 49 to 06/89/2016 20 -------------------------~ Jan 1 Mar 1 Ma!:;! 1 . Jul 1 Sep 1 Nov 1 Dec 31 Feb 1 Apr 1 Jun 1 Aug 1 Oct 1 Dec 1 Day of Year ( Extreme Max --Ave Max --Ave Min Extreme Min] Me$tel'-n R 9iond C li».-it.e Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-74 June 20, 2008 - The combination of strong high pressure centered over Arizona and weak offshore flow generated extreme heat conditions across Central and Southern California. Across many sections of the area, afternoon temperatures climbed to between 100 and 114 degrees which set numerous high temperature records. The extreme heat resulted in several power outages due to excessive electrical use. The automated sensor at Paso Robles reported a high temperature of 107 with a heat index of 105 degrees. Probability of Future Occurrences Occasional—Temperature extremes are likely to continue to occur annually in the San Luis Obispo County planning area. Climate Change Considerations According to the Central Coast Region Report of California’s Fourth Climate Change Assessment report, both average high and average minimum temperatures are expected to increase, with the greatest increases in the inland regions of the Central Coast. Due to the rising temperatures heat waves are likely to become more frequent, which will have direct impacts on human health in terms of heat related illness. San Luis Obispo’s large farming and viticulture production which employs 1,000s of outdoor laborers will be vulnerable to the rising temperatures and most at risk for heat related illnesses. Residents on the coastal regions of County will also be vulnerable to rising temperatures, as many of the homes of the coast do not have air conditioning units as there was less of a need in the past and may be less prepared compared to the inland region of the county to adapt to extreme heat events. Cascading impacts include increased stress on water quantity and quality, degraded air quality, and increased potential for more severe or catastrophic natural events such as heavy rain, droughts, and wildfire. Another cascading impact includes increased duration and intensity of wildfires with warmer temperatures. According to the 2013 document, “Preparing California for the Extreme Heat”, Cal-Adapt projects that throughout California urban and rural population centers will experience an average of 40 to 53 extreme heat days by 2050 and an average of 40 days by 2099; compared to a historical average of 4 per year (CalAdapt 2013). Extreme heat has also been shown to accelerate wear and tear on the natural gas system and electrical infrastructure (California Natural Resources Agency 2018a). Projected increases in summer demand associated with rising temperatures may increase risks to energy infrastructure and may exceed the capacity of existing substations and distribution line infrastructure and systems. Vulnerability: Extreme Heat General Property Recent research indicates that the impact of extreme heat, particularly on populations, has been historically under-represented. The risks of extreme heat are often profiled as part of larger hazards, such drought or wildfire. However, as temperature variances may occur outside of larger hazards or outside of the expected seasons but still incur large costs, it is important to examine them as stand-alone hazards. Extreme heat may overload demands for electricity to run air conditioners in homes and businesses during prolonged periods of exposure and presents health concerns to individuals outside in the temperatures. While extreme heat rarely damages buildings, it can cause infrastructure damage to roads. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-75 People Traditionally, the very young and very old are considered at higher risk to the effects of extreme heat, but any populations outdoors during periods of extreme temperatures are exposed, including otherwise young and healthy adults and homeless populations. While everyone is vulnerable to extreme heat incidents, some populations are more vulnerable than others. Extreme heat poses the greatest danger for San Luis Obispo’s thousands of outdoor laborers who support the County’s agriculture economy who are exposed to extreme temperatures and at higher risk of heat related illnesses than other populations of the county. Climate change projections of rising temperatures in the region also pose a risk to the County’s coastal population who is more accustomed to cooler temperatures. and therefore, may have never needed air conditioning in their homes. This could result in some populations being unprepared for an extreme heat event. The elderly, children, people in poor physical health, and the homeless are also vulnerable to exposure. Arguably, the young-and-otherwise-healthy demographic may also experience a higher vulnerability of exposure, due to the increased likelihood that they will be out in temperatures of extreme heat, whether due to commuting for work or school, conducting property maintenance such as lawn care, or for recreational reasons. Social Vulnerability The North County inland area has the potential for the highest extreme heat days. Based on the SoVI data presented and discussed in subsection 4.4.1, within this region, the communities of Paso Robles San Miguel, and Shandon have the highest social vulnerability. Critical Facilities and Infrastructure Extreme heat can affect road infrastructure, damaging and buckling road surfaces. Other direct impacts to critical infrastructure includes power line sagging and power surges. Critical infrastructure that relies on public utility systems that could be overloaded may result in impacts during extreme heat events. Peak demand exceeding the local utility’s capacity for supply can lead to blackout or brownout conditions. The loss of utilities or power outages during extreme heat events could also result in adverse secondary impacts to sensitive populations. Electrical power outages may impact response capabilities or care capabilities for hospitals and clinics. Economy Extreme heat impacts on the economy may be more indirect compared to other hazards. San Luis Obispo has a large agriculture economy. As noted previously outdoor laborers who are exposed to extreme heat and at a high risk of heat related illnesses, and a long-term heat event could cause work interruptions. Crops are also impacted by heat events and could have an impact on the overall economy in the county. According to the USDA RMA Indemnity Report, since 2015 there have been 65 heat events that have resulted in $3,569,208 in crop losses in the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-76 Historic, Cultural, and Natural Resources Extreme heat may cause temporary drought-like conditions. For example, several weeks of extreme heat increases evapotranspiration and reduces moisture content in vegetation, leading to higher wildfire vulnerability for that time period even if the rest of the season is relatively moist. Future Development Since structures are not usually directly impacted by severe temperature fluctuations, continued development is less impacted by this hazard than others in the plan. However, pre-emptive measures such as construction of green buildings that require less energy to heat and cool, use of good insulation on pipes and electric wirings, and smart construction of walkways, parking structures, and pedestrian zones that minimize exposure to severe temperatures may help increase the overall durability of the buildings and the community to the variations. Continued development also implies continued population growth, which raises the number of individuals potentially exposed to variations. Public education efforts should continue to help the population understand the risks and vulnerabilities of outdoor activities, property maintenance, and regular exposures during periods of extreme heat. Risk Summary – Extreme Heat • There have been three notable extreme heat events in past 68 years in San Luis Obispo County; • The inland area of the eastern County is more likely to experience an extreme heat event • Coastal areas are potentially vulnerable to extreme heat due to lack of acclimatization to high temperatures and less air conditioning; • Highest recorded temperature for the San Luis Obispo Area is 112°F on Sep. 14, 1971 • Highest recorded temperatures for North County Coastal Area is 102°F on Sept. 14, 1984 • Highest recorded temperatures for Inland Area is 117°F on Aug. 13, 1933 • High recorded temperatures for South County Area is 108°F on Aug. 28, 1962; • Extreme heat can have considerable impacts on human health, the natural environment and the economy; • The County’s agriculture economy is at risk of extreme heat from outdoor laborers being vulnerable to heat illnesses as well as crop losses due to heat; • The very young, the very old, people with poor physical health and the homeless are more susceptible to the impacts of extreme temperatures; • Climate change is projected to increase temperatures in the Central Coast region of the State. • Related hazards: Drought, Land Subsidence, Wildfire, Agriculture/Pest Infestation/Plant Disease/Tree Mortality, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-77 Table 5-30 Hazard Risk Summary – Extreme Heat Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Extensive Occasional Negligible Low City of Arroyo Grande Extensive Occasional Negligible Low City of Atascadero Extensive Occasional Negligible Low City of Grover Beach Extensive Occasional Negligible Low City of Morro Bay Significant Highly Likely Limited Medium City of Paso Robles Extensive Highly Likely Limited High City of Pismo Beach Significant Likely Limited Low City of San Luis Obispo Extensive Occasional Negligible Low Avila Beach CSD Significant Occasional Negligible Medium Ground Squirrel Hollow CSD Limited Likely Negligible Medium Heritage Ranch CSD Extensive Highly Likely Critical High Los Osos CSD Significant Likely Limited Medium Nipomo CSD Limited Likely Negligible Low San Miguel CSD Extensive Likely Catastrophic High San Simeon CSD Significant Likely Limited Low Templeton CSD Significant Highly Likely Limited High Cayucos Sanitary District Extensive Likely Critical High Port San Luis Harbor District Extensive Highly Likely Limited Medium San Luis Obispo FCWCD Extensive Occasional Negligible Low South San Luis Obispo Sanitary District Extensive Occasional Negligible Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-78 5.3.5 Agricultural Pest Infestation, Plant Disease, Marine Invasive Species and Tree Mortality Hazard/Problem Definition Agricultural pests and pathogens (insects, fungi, bacteria, viruses and invasive plants) cause injury or destruction to crops or livestock. From exotic fruit flies to noxious weeds, California’s agriculture can be impacted by a wide variety of invasive pests. These pests pose significant threats to the state’s agricultural crops, economy, food supply and native habitat. The number of invasive pests and pathogens newly detected in California and the rest of the United States has increased at alarming rates in recent years, and that trend is projected to continue into the future. Invasive species are not just contained to dry land. Marine invasive species can take over enclosed water ecosystems, disrupting delicate ecological structure and displacing entire native species. Marine invasive species can also foul pipes of hydroelectrical facilities, water works, and other industrial facilities, impairing facility functions. A specific concern of the county is tree vulnerability and mortality. Over 100 million trees have died and more continue to die due to many years of drought that have weakened trees, and left millions of acres of forestland highly susceptible to insect attacks. The drought stress is exacerbated in forests with too many trees competing for limited resources, especially water. Forest pests (insects and diseases) annually destroy ten times the volume of timber lost to due to forest fires. Native bark beetles took hold in Southern California forests and caused unprecedented tree mortality. Pitch Canker disease has attacked Monterey Pines along the central coast. Sudden Oak Death has been found in 14 counties in California and has killed thousands of oaks. Tree losses due to drought stresses and bark beetle attacks are expected to increase until precipitation levels return to normal or above normal for one to multiple years. Geographic Area Agricultural pests usually occur in rural areas used for the growing of crops, though tree mortality can affect urban and rural forested areas; marine invasive species usually occur in contained aquamarine areas, including rivers, creeks, ponds and lakes. In San Luis Obispo County, agriculture lands are interspersed across the county but largely focused in the North County region. Figure 5-22 shows land use across the county; agricultural lands are shown in light green. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-79 Figure 5-22 San Luis Obispo – County Land Use During discussions with the HMPC, it was noted that while most agricultural pests occur in rural areas, the initial introduction of those pests is often due to human/vehicle movement and occurs in more urbanized areas. Often, especially in the case of insect pests, the species will first become established in a residential or urban area, and then move into croplands. Marine invasive species are a threat to marine areas with a relatively enclosed, self-contained ecosystem. Figure 5-22 shows main bodies of water and waterways in the county; specific points of interest include Nacimiento Reservoir, Soda Lake, Twitchell Reservoir, Santa Margarita Lake and Whale Rock Reservoir. The Dam Incident section has more information on reservoirs and other bodies of water. Tree Mortality: Tree mortality was identified as an additional drought impact of significance to the county during the 2019 update. Tree mortality is a cascading impact which also affects (or worsens) other hazards such as wildfire, agricultural and biological hazards, and wind. In recent years, due to the multi- year drought throughout the planning area and state-wide, a vast number of trees have been (and continue to be) impacted within San Luis Obispo County foothill and mountain communities and beyond. Standing dead trees could fall and pose a risk to people, buildings, power lines, roads and other infrastructure. In addition, drought-impacted trees become susceptible to diseases and insect infestations (bark beetle) further adding to the risk of tree mortality and related potential impacts. California established the California Tree Mortality Task Force in October 2015. As part of the work of the Task Force, areas of tree mortality were identified and mapped to show areas that pose the greatest potential to harm people and/or property. These areas, known as High Hazard Zones, are the areas prioritized for tree removal, and are separated into Tiers. Tier I High Hazard Zones are areas where ParlfletJ<-fflll ••• 10 20 MIies SAN LUIS OBISPO COUNTY RURAL LAND USE CATEGORY MAP Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-80 mortality and the asset to be protected (utilities, roads, recreation sites etc.) directly coincide with mortality identified by the USFS. Tier 2 HHZ is based on watersheds and are intended to focus on ecosystem health and identify watersheds where there is both the greatest amount of ecological assets to be protected, as well as the greatest threat. Figure 5-23 shows High Hazard Zones in the county, as well as areas of tree mortality and community boundaries. Paso Robles, Atascadero, Pismo Beach, Arroyo Grande, Grover Beach and the unincorporated county are all impacted by Tier 2 High Hazard Zones; Tier I High Hazard Zones are found in the unincorporated county, as well as Atascadero. Figure 5-23 San Luis Obispo – Tree Mortality and High Hazard Zones Extent (Magnitude/Severity) 2017 San Luis Obispo County annual crop statistics released by the San Luis Obispo County Department of Agriculture/Weights and Measures show that agricultural assets in the county have a gross valuation of $924,698,000. The top twenty value crops based on county data shown in the following table. Figure 5-24 San Luis Obispo County – 2017 Top Twenty Value Crops Crop Value Wine Grapes (All) $267,662,000 Strawberries $228,169,000 Cattle and Calves $42,241,000 Broccoli $42,996,000 PACIFIC OCEAN Tree Mortality -Tie r 1 High Hazard Zones 2018 ner 2 High Hazard Zones 2016 --Waterways -Lakes -+-----+ Railroads --Highway --Freeway Counties ••• Map compiled 2/201 9 ; intended for planning purposes only. Data Source: San Luis Obispo County, US Census T IGER Database, CA Open Data Portal, CalF ire FRAP Tu lare 10 20 40Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-81 Crop Value Vegetable Transplants $33,119,000 Avocados $27,295,000 Cut Flowers $27,165,000 Cauliflower $23,253,000 Head Lettuce $17,477,000 Lemons $16,016,000 Leaf Lettuce $11,161,000 Outdoor Ornamentals $9,320,000 Celery $8,405,000 Rangeland Grazed $8,096,000 Grain Hay $2,447,000 Alfalfa Hay $2,421,000 Barley $1,761,000 English Walnuts $1,264,000 Squash $1,027,000 Peas $532,000 Source: San Luis Obispo County Department of Agriculture/Weights and Measures Different pests can impact different crops in different ways; while there is no scale to define the extent of an infestation, a pest could have a major economic impact on the value of infested crops. According to Cal-IPC, invasive plants cost California $82 million every year in control, monitoring and outreach; estimated actual impacts can reach into the billions. Previous Occurrences San Luis Obispo County has a demonstrated vulnerability to pest infestation including the Vine Mealybug, Glassy-winged sharpshooter and Pine Pitch Canker. Vine Mealybug: The Vine Mealybug (VMB), Planococcus ficus, is an exotic pest in California that was first found in San Luis Obispo County in 1991. It causes an enormous amount of damage, is very difficult and costly to treat, and can lead to total crop loss without the diligent use of insecticide treatment. Although it has only been found on grapes so far in California, alternate hosts include avocados, citrus and other crops. It is currently seen in most grape growing counties of California including vineyards in San Luis Obispo, Santa Barbara and Monterey counties. The Vine Mealybug has 5 to 7 generations per year, enabling populations to grow very rapidly. Unlike other mealybugs, all life stages of the VMB can be present year-round on a vine. During winter months, eggs, crawlers, nymphs, and adults are found under bark, within developing buds, and on roots. Prevention: The female VMB can easily be transported through contaminated nursery stock, equipment, personnel as well as birds and other wildlife. Vineyard managers need to employ strict biosecurity and sanitation in the vineyard. Best Management Practices (BMP) in the vineyard and at the wineries that process the grapes can reduce the spread of VMB. Monitoring vineyards for the presence of VMB by ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-82 detection trapping is essential to the early detection and successful treatment of the pest. It is unlikely that VMB will be eradicated from most vineyards. With early detection and vigilant treatment VMB populations can be kept in check. Glassy-winged sharpshooter (GWSS): The Glassy-winged sharpshooter (Homalodisca coagulata) is an insect that poses a significant hazard to California agriculture. When feeding, it can transmit Pierce's disease, caused by the bacterium, Xylella fastidiosa, to grapevines, and other diseases to almond trees, alfalfa, citrus and oleanders. First detected in California in 1994, this insect has spread throughout Southern California and into the southern San Joaquin Valley. The first major infestation in California occurred in 1999 in Temecula, where more than 300 acres of vineyards were destroyed. Figure 5-25 Glassy-winged Sharpshooter The Glassy-winged sharpshooter is considered a serious threat to San Luis Obispo County’s multimillion- dollar wine industry because it spreads bacteria that cause a lethal disease to grape plants. It is also a nuisance to homeowners because it deposits a sticky residue on plant. Localized infestations have been found in San Luis Obispo County, although these are believed to be eradicated. A single glassy-winged sharpshooter was found in a trap in July 2017; additional inspection and survey found no additional sharpshooters in the area, and no signs of an established breeding population were detected. Prevention: The San Luis Obispo County Agricultural Commissioner’s Office (SLOCACO) is in partnership with the California Department of Food and Agriculture (CDFA), the United States Department of Agriculture, the University of California, and other county Agricultural Commissioner’s offices to collaborate with the Pierce’s Disease Control Program (PDCP). The PDCP works to minimize the statewide impact of Pierce’s Disease and the Glassy-winged sharpshooter. The strategy is to slow or stop the spread of GWSS while both short and long-term solutions to Pierce’s disease are developed. This strategy relies on the following five elements: • Containing the Spread • Statewide Survey and Detection • Rapid Response • Outreach • Research The bulk of the SLOCACO’s efforts have been in excluding the sharpshooter from San Luis Obispo County and implementing a detection program most heavily weighted in nursery and urban settings. The ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-83 exclusion efforts for the program consist mainly of inspecting incoming plant shipments from infested portions of the state bound for wholesale and retail nurseries throughout San Luis Obispo County. The detection efforts for the program consist mainly of deploying insect traps in nursery and urban residential areas. Monitoring of the traps is performed every two weeks along with periodic relocation of the traps. Pine Pitch Canker: A condition that is threatening the health of the Monterey pine trees in the Cambria area is the Pine Pitch Canker (Fusarium subglutinans pini). This disease, native to Mexico and the southeastern United States, was first found in California in 1986. Since then, it has been found in 16 counties, and is spread by insects, the use of contaminated tools, and the transport of infected wood. The Pine Pitch Canker is considered to be a significant threat to the continued survival of the Monterey Pine ecosystem. Large native stands of the trees are now only found in the Ano Nuevo, Monterey, and Cambria areas. If a tree becomes infected with the Pine Pitch Canker, the disease can spread quickly, and can result in the rapid death of the tree. If an infected or dead tree is not properly removed, it not only becomes a threat to spread the disease, but can also result in a safety threat, as a large dead tree is a fire hazard as well as presenting the potential to become uprooted and to fall during a storm. This pathogen is also a serious concern to the commercial nursery industry. Prevention: Preventative measures consist of pest detection, exclusion and eradication in production nursery settings, and informing the public and nursery industry about the dangers of moving infected plant material out of infested areas. Light Brown Apple Moth: The Light Brown Apple Moth (Epiphyas postvittana), is native to Australia and is found in New Zealand, the United Kingdom and Hawaii. The range of host plants is broad with more than two-thousand plant species known to be susceptible to attack by this pest, and more than 250 crops. It threatens California’s environment—including cypress and oak trees—by destroying, stunting or deforming young seedlings and damaging new growth in the forest canopy. The moth also feeds on host plants and damages or spoils the appearance of ornamental plants, citrus, grapes, and deciduous fruit tree crops. In 2010, nine coastal California counties were under quarantine for the presence of this pest. State and federal agriculture officials are currently developing sterile insect technology to combat the infestation. In 2015, light brown apple moths were identified in the city of San Luis Obispo for the first time. Prevention: Preventative measures consist of pest detection, exclusion and eradication. Figure 5-26 Light Brown Apple Moth ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-84 During the review process, a Hazard Mitigation Planning Committee member representing the San Luis Obispo County Department of Agriculture noted that as of 2019, the Light Brown Apple Moth is established across most of coastal California, and that efforts are underway to de-classify this species as an official rated pest insect. While the Light Brown Apple Moth remains in the 2019 Hazard Mitigation Plan, future versions may remove this pest from consideration. Asian Citrus Psyllid/Citrus Greening Disease (Huanglongbing): The Asian citrus psyllid (ACP) is a pest that acts as a carrier or vector spreading “huanglongbing”, a devastating disease of citrus trees. This bacterial disease is transmitted to health trees by the psyllid after it feeds on infected plant tissue. ACP was first identified in San Luis Obispo County in March 2014 in Arroyo Grande. In response to the identification, the San Luis Obispo Agriculture Department implemented a quarantine in a five-mile radius from the site. The quarantine required growers and nursery owners to use pesticides to eradicate any ACP before moving fruit or trees out of the area. Numbers of the ACP identified in San Luis Obispo County have been steadily on the rise; according to the California Department of Agriculture, more than 100 invasive insects were found in southern San Luis Obispo County (specifically in the Nipomo area) in 2018; this was triple the number found in 2017. The County has a proactive detection program, with approximately 2,000 traps set up around the county, mostly in the South County. Symptoms and Impact: ACP damages plants directly through its feeding activities; new shoot growth that is heavily infested by psyllids does not expand and develop normally and is more susceptible to breaking off. While direct damage is serious, there is even greater concern that the psyllid is an efficient vector of the bacterium that causes the economically devastating disease citrus greening, or huanglongbing. Prevention: The California Department of Food and Agriculture tracks the presence of pests and disease and establishes quarantines to help protect California citrus trees. Invasive Shot Hole Borer/Goldspotted Oak Borer: The goldspotted oak borer (GSOB) is an invasive pest contributing to the ongoing oak tree mortality; it is a concern for both native oaks and oak woodlands. The invasive shothole borer are potential pests for agriculture, native trees and urban forests. The insects can attack over 110 tree species, including sycamore, cottonwood, alder, willows and boxelders. As of March 2019, these insects have not been located anywhere in San Luis Obispo County, but have been found in surrounding areas. The University of California Cooperative Extension notes isolated areas of infestation in Riverside, Orange and Los Angeles counties. Symptoms and Impact: Widespread tree mortality caused by borer beetles can have severe implications and impacts to the environment and human safety, including tree death and increased wildfire danger. Prevention: Most of the prevention activities undertaken by the county revolve around public information and awareness. Many wood-boring pests are spread by the transport of infested wood material. According to the University of California Agriculture and Natural Resources, researchers believe that the goldspotted oak borer may have traveled to California from Arizona on infested firewood. Refraining from moving firewood, proper disposal of infested material and proper pruning are recommended to prevent the spread of these pests. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-85 Sudden Oak Death: A disease of oak trees and more than one hundred other plant species, Phytophthora ramorum (or Sudden Oak Death), has been found throughout much of coastal California, and was identified in San Luis Obispo County for the first time in 2016 in Bay Laurel Trees. This disease has killed over a million trees in Coastal California forests and has the potential for broad ecological changes to natural areas, including significantly increasing the risk of wildfire. Figure 5-27 Sudden Oak Death This pathogen is also a serious concern to the commercial nursery industry. Symptoms and Impact: On oaks and tanoak, cankers are formed on the stems. Cankered trees may survive for one to several years, but once crown dieback begins, leaves often turn from green to pale yellow to brown within a few weeks. Figure 5-28 Bleeding Ooze from a Canker on an Oak Black or reddish ooze often bleeds from the cankers, staining the bark, as well as killing the mosses that grow on it. Bleeding ooze may be difficult to see if it has dried or has been washed off by rain. Necrotic bark tissues surrounded by black zone lines are present under affected bark. Because these symptoms can also be caused by other Phytophthora species, laboratory tests must be done to confirm pathogen identity. Infected coast live oaks sometimes gradually lose their leaves and fade out slowly. If bleeding oaks and leaf spots on bay laurel or other symptomatic hosts are adjacent to one another, the presence of Phytophthora ramorum is likely. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-86 Prevention: Preventative measures consist of pest detection, exclusion and eradication in production nursery settings, and informing the public and the nursery industry about the dangers of moving infected plant material out of infested areas. Quagga/Zebra Mussels: Quagga/Zebra mussels are non-native freshwater mussels from eastern Europe that clog waterways, undermine healthy lake ecosystems, ruin boat engine cooling systems, and financially burden water resources agencies. Prolific breeders, these mussels can overrun a lake causing hundreds of thousands of dollars’ worth of damage annually. Rapid reproduction can negatively disrupt an ecosystem in a short amount of time. Once these mussels are introduced into a waterway, there is no way to fully eradicate the species. Figure 5-29 Quagga/Zebra Mussels According to the daily USGS Nonindigenous Aquatic Species Database, no reported Quagga/Zebra mussels have been found in waterways in the county as of January 28, 2019, though occurrences have been reported both north and south of the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-87 Figure 5-30 Zebra and Quagga Mussels Sightings Distribution Map Source: USGS; San Luis Obispo County general area noted by red square Prevention: California has passed the Dreissenid Mussel Prevention Program, which requires vulnerability assessments on uninfested reservoirs and development of programs to prevent the introduction of the mussels, including public information, monitoring and management of recreational activities. San Luis Obispo County currently engages in a public information campaign to spread information regarding this invasive species. Probability of Future Occurrences While probability of future occurrence is usually calculated based on past experience, different pests have different recidivism rates across the county. Based on past experience, pests and invasive species will continue to present a constant threat to the county and its jurisdictions. Climate Change Considerations California’s Fourth Climate Change Assessment (2018) notes that “climate change impacts terrestrial ecosystems and wildlife in multiple ways, including invasion by exotic species, prevalence of wildlife disease, and loss of native habitats.” Changing climate conditions can impact viable living areas of species and cause migration; changing habitat temperatures can make previously undesirable habitats welcoming for new species and lengthen habitable seasons. ••• Zebra and Quagga Mussel Sightings Distribution Dreissena poly morpha and D. ros triformls bugensis • Zebra mussel occurrences 0 Quagga mussel occurrences • Zebra or Quagga mussel ooourrences 0 Both species occurrences ■ Zebra/Quagga mussels eradicated :J Zebra/Ouagga mussels fa iled Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-88 Vulnerability General Property Grapes (glassy winged sharpshooter, vine mealybug), trees (pine pitch canker, light brown apple moth, sudden oak death) and reservoirs and waterways (zebra mussels) are all at risk from invasive species and pests. An infestation of agriculture pests could impact crop yields, potential destroying whole fields. Zebra mussels can cause damage to water-based property, including boat engines. Between 2015 and 2018, the RMA paid no indemnities due to damage from insects, and $22,900 in indemnities due to damage from crop disease. People A widespread infestation of animals/livestock and crops could impact the economic base of the county and its communities. According to the USDA 2012 Census of Agriculture, San Luis Obispo 2,666 farms, - 4% change from the previous census in 2007. Jobs could be negatively impacted during an agriculture emergency; jobs tangentially tied to the agriculture industry could also be affected. Disease can exacerbate the impacts from other hazards, and an example of this is adverse weather; dead branches can be broken by high winds, and there are reports of these branches falling and causing harm to people. Social Vulnerability Based on the SoVI data presented and discussed in subsection 4.4.1, the communities located in north county San Luis Obispo where much of the grape production activities take place in the county are also ranked as having the highest overall social vulnerability, including San Miguel and Paso Robles. These communities as well as those working in the agricultural sector in south county, would likely be impacted by the effects of agricultural hazards compared to coastal areas of the county. Critical Facilities and Infrastructure The major pest/invasive species identified in this section with the potential to impact critical infrastructure is the quagga/zebra mussel. In large concentrations, zebra mussels can accumulate in waterways, clogging pipes and damaging equipment used for drinking water and irrigation. As discussed previously, dead trees can exacerbate the impacts of other hazards; more information on this hazard can be found in the Vulnerability section of the Adverse Weather section. Additionally, dead trees can accelerate the spread of wildfire, adding to the vulnerability of infrastructure; analysis of wildfire risk in relation to parcels is located in the Adverse Weather section as well. Economy According to the University of California’s Center for Invasive Species Research, it has been estimated in California alone that invasive pests cost the state at least $3 billion per year. Nationally, it is estimated that invasive species cost the USA $138 billion per year. Economic impacts include both prevention, response and recovery costs. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-89 Historic, Cultural, and Natural Resources Invasive species typically harm native species through predation, habitat degradation and competition for shared resources; they can muscle native species out of natural habitats and are a leading cause of population decline and extinction in animals. Tree mortality raises the wildfire threat in healthy forests, increasing the vulnerability, strength, speed and destruction of fires in the area. Future Development Most likely, good development practices in the future would not have an impact on the planning area’s vulnerability to agricultural pests, plant diseases, marine invasive species or tree mortality. Risk Summary • The overall significance is Medium • San Luis Obispo is vulnerable to a variety of plant diseases, infestations and invasive species; not all pests identified in this section • Rapid detection, response, efforts are essential to stop the spread of agricultural pests, plant diseases and marine invasive species • Infestations, pests and invasive species could cost millions in response and recovery • There are public programs in place regarding prevention, response and eradication to pests and infestations • Risk Management Agency (RMA) crop indemnities for insect and disease damages have been relatively low compared to total crop value • Infestations, pests and diseases can worsen impacts from other hazards including wind and drought, and can cascade into other hazards including infrastructure failure and wildfire • Related hazards: Adverse Weather, Drought, Wildfire Figure 5-31 Risk Summary by Jurisdiction Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Limited Highly Likely Negligible Medium City of Arroyo Grande Limited Highly Likely Negligible Medium City of Atascadero Limited Highly Likely Negligible Medium City of Grover Beach Limited Highly Likely Negligible Medium City of Morro Bay Limited Unlikely Negligible Low City of Paso Robles Limited Limited Unlikely Low City of Pismo Beach Limited Unlikely Negligible Low City of San Luis Obispo Limited Highly Likely Negligible Medium Avila Beach CSD Limited Unlikely Negligible Low Ground Squirrel Hollow CSD Limited Unlikely Negligible Low Heritage Ranch CSD Limited Unlikely Negligible Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-90 Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance Los Osos CSD N/A Nipomo CSD Limited Unlikely Negligible Low San Miguel CSD Significant Occasional Limited Medium San Simeon CSD Significant Likely Limited Low Templeton CSD N/A Cayucos Sanitary District Limited Unlikely Negligible Low Port San Luis Harbor District Extensive Unlikely Negligible Low San Luis Obispo FCWCD Limited Highly Likely Negligible Low South San Luis Obispo Sanitary District Limited Highly Likely Negligible Medium ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-91 5.3.6 Biological Agents (Naturally Occurring) Hazard/Problem Definition Public health associated hazards may be naturally occurring or the result of malevolent acts such as terrorism. The Hazard Mitigation Planning Committee determined in 2013 that this plan should focus on naturally occurring hazards such as pandemic flu and flood and waterborne illnesses; the 2019 update follows this precedent. Terrorism and other homeland security concerns are addressed separately by the county’s Office of Emergency Services. The following diseases caused by naturally occurring biological agents possess epidemic potential for San Luis Obispo County. Influenza (Pandemic) Influenza viruses have for centuries threatened the health of humans and animals worldwide by causing a contagious respiratory illness with mild to severe severity. Annual influenza epidemics create a significant public health burden with the highest risk of complications occurring in the elderly, children under the age of 2, and individuals with prior medical conditions. This virus’ diversity and propensity for mutation has prevented the development of both a universal vaccine and highly effective antiviral drugs. Ongoing concern exists over the potential emergence of a new strain of influenza with the ability to infect and be passed between humans. Because humans won’t have immunity to this novel virus, a worldwide epidemic (pandemic) could result as recently occurred. Three human influenza pandemics have occurred in the 20th century each resulting in illness in approximately 30 percent of the world population and death in up to 2 percent of those infected. The 1918 Spanish Influenza (H1N1) pandemic occurred towards the end of World War I. More people died during the flu pandemic than were killed during the entire war. The influenza death toll was an estimated 50–100 million worldwide. In the United States, about 675,000 died. The 1957 Asian Influenza (H2N2) pandemic killed 1–2 million worldwide and caused approximately 70,000 deaths in the United States. The third pandemic, the Hong Kong Influenza (H3N2), occurred in 1968-69 and killed an estimated one million people worldwide. More recently, a novel influenza virus emerged, the 2009 H1N1, which spread worldwide and caused the first flu pandemic in over 4 decades. In the U.S., the Centers for Disease Control and Prevention (CDC) believed H1N1 may have been responsible for up to 17,000 deaths as of May 2010. According to the California Department of Public Health, 2018 was an especially strong flu season in the Golden State. San Luis Obispo County is proactive in prevention and education efforts every flu season, ensuring residents are informed of the dangers of the flu and encouraging flu shots and other prophylactic measures. Prevention: Preventing transmission of influenza virus and other infectious agents within healthcare settings requires a multi-faceted approach. Spread of influenza virus can occur among patients, healthcare personnel, and visitors. Additionally, healthcare personnel may acquire influenza from persons in their household or community. Prevention strategies include: • Administration of influenza vaccine ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-92 • Implementation of respiratory hygiene and cough etiquette • Appropriate management of ill healthcare personnel • Adherence to infection control precautions for all patient-care activities and aerosol-generating procedures • Implementing environmental and engineering infection control measures. General public prevention measures include: • Educating the public on cough etiquette and basic personal hygiene • Immunization with available influenza vaccine Once an epidemic has been identified, the County of San Luis Obispo County Public Health Department will respond in the following manner: 1. Investigate the epidemic to determine its etiology, level of severity, mode of transmission, and persons affected and at risk. 2. Determine and institute control measures to prevent further spread. 3. Communicate control measures to the public and healthcare professionals. The San Luis Obispo Community Health Assessment, published in July 2018 notes that nationally, an estimated 200,000+ people are hospitalized each year due to flu-related complications. The report notes that from 2014-2016, less than half (41%) of people in the county received their annual flu shot – lower than the state overall in the same period. Between 2000 and 2010, an average of 43 deaths per year occurred in the county with a primary cause of influenza or pneumonia. Influenza/pneumonia was the 9th leading cause of death in the county between 2005 and 2013. Novel Infections (SARS et al) Novel infections, particularly those of viral origin, pose a tremendous risk to public health because the general public has no immunity from prior infections or vaccination, and because a vaccine is not readily available. For influenza viruses, it takes at least six months to produce large quantities of vaccine. For other viral pathogens such as HIV, a vaccine that protects individuals against HIV infection has been the goal of many research programs for the past two decades, yet only in the past few years has a vaccine reached the clinical trial stage. Vaccines, which are believed to work by activating the body's ability to produce antibodies, eliminated or curtailed smallpox, polio and other feared viral diseases. One novel virus that took the world by surprise was the appearance of the Severe Acute Respiratory Syndrome (SARS) virus in China at the end of 2002. Within months, this coronavirus spread internationally, with the help of air travel, resulting in 8,098 cases in 26 countries with 774 deaths occurring. Prevention: Preventative measures consist of preparedness planning to enable the rapid detection, investigation and detainment of unexplained clusters of illness or death. Isolation of persons with unexplained potentially infectious disease may be indicated. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-93 Food and Waterborne Illness Food and waterborne illnesses are major global health problems resulting in over 2 million deaths per year. In the United States alone, an estimate 76 million cases of foodborne disease occurs annually resulting in 325,000 hospitalizations and 5,000 deaths. The following biological agents have been historical threats to the food and water supply in this county. • Staphylococcus aureus • Salmonella species • E. coli 0157: H7 • Campylobacter species • Amebiasis • Hepatitis A • Shigella species Food-borne outbreaks are identified by the presence of illness shortly following a meal. Illness can occur within a few hours and up to several weeks. Symptoms range from mild to severe: • Upset stomach • Abdominal cramps • Vomiting • Diarrhea • Fever • Dehydration Intrinsic problems in food or water production, processing, storage, distribution, or preparation can all result in contamination of the food supply. Because food production and distribution practices are constantly changing, new unforeseen problems will continue to emerge. The need for ongoing monitoring and control efforts is essential. Prevention: Preventative measures are based on the principles of: avoiding food contamination, destroying contaminants, and preventing further spread. Specifically, these include: • Education of food handlers about sanitation, food and personal hygiene, kitchen cleanliness, temperature control, thorough cooking of animal related food products and hand washing before, during and after food preparation. • Reducing food-handling time from initial preparation to service to be no more than 4 hours at ambient temperature. • Teaching food handlers, the importance of keeping wounds covered and not working with nasal or eye infections, boils, abscesses or other purulent skin lesions. • Exclude individuals with diarrhea from food handling and from care of hospitalized patients, the elderly and children. • Education of farmers on the importance of sanitary work practices and safe food preparation and transportation. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-94 Antibiotic Resistant Microorganisms (e.g. MRSA, MDR and XDR-TB) MRSA: Methicillin-resistant Staphylococcus Aureus (MRSA) is a bacterium that is resistant to certain antibiotics called beta-lactams. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. In the community, most MRSA infections are skin infections. More severe or potentially life-threatening MRSA infections occur most frequently among patients in healthcare settings. While 25% to 30% of people are colonized in the nose with staphylococcus, less than 2% are colonized with MRSA. MRSA Community Transmission: MRSA infections, as with all Staphylococcus, are usually spread by having contact with someone’s skin infection or personal items they have used, like towels, bandages, or razors that touched their infected skin. These infections are most likely to be spread in places where people are in close contact with others—for instance, schools and locker rooms where athletes might share razors or towels. Factors that have been associated with the spread of MRSA skin infections include: close skin-to-skin contact, openings in the skin such as cuts or abrasions, contaminated items and surfaces, crowded living conditions, and poor hygiene. People may be more at risk in locations where these factors are common, including: athletic facilities, dormitories, military barracks, households, correctional facilities, and daycare centers. Prevention: Preventative measures consist of good hygiene practices, using Standard Precautions in healthcare settings and patient education. MDR and XDR Tuberculosis: Tuberculosis (TB) is a disease caused by the infectious bacterium Mycobacterium tuberculosis. It is responsible for 1.7 million deaths globally each year (230,000 are HIV associated cases). Person to person transmission of TB occurs when droplet nuclei are inhaled (typically occurs after sustained or recurrent exposure to an infected patient from coughing, sneezing, talking, singing or spitting). The aerosolized particles (bacilli) are inhaled into the lungs and subsequently ingested by alveolar macrophages initiating a new infection. The treatment regimen for infected patients involves multiple drug therapy for a minimum of 6 months. If not properly treated, TB can be fatal. Outbreaks of multidrug-resistant TB (MDR-TB) defined as exhibiting resistance to at least isoniazid and rifampicin, have occurred primarily in settings where HIV-infected persons congregate such as hospitals, prisons, drug treatment clinics and HIV residences. These outbreaks have been associated with high fatality rates. Transmission of M. tuberculosis to healthcare workers and other patients also occurred. Recently, extensively resistant TB (XDR-TB) has emerged. This is defined as MDR-TB plus resistance to any fluoroquinolone and any of the three injectable drugs (amikacin, capreomycin and kanamyin). Outbreaks have primarily occurred in situations where the use of second-line TB drugs has been used and poorly managed. A 2005-2006 outbreak in South Africa resulted in a 98% fatality rate and a median survival rate of 16 days from the date of XDR-TB diagnosis. Prevention: Preventative measures include: 1) Promptly identifying and treating infectious patients, 2) Active case finding for secondary cases of TB amongst contacts with subsequent treatment, 2) Public education, 3) Reducing overcrowding, and 4) Providing outreach services for direct supervision of patient therapy. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-95 Vector-Borne Diseases One area of particular concern for the County of San Luis Obispo is the limited surveillance for vector borne diseases such as West Nile Virus. Surveillance efforts throughout California have been extensive, including human and horse case detection, and WNV testing of mosquitoes, sentinel chicken flocks, and dead birds. Because San Luis Obispo County is one of the few remaining counties in California without a Vector Control District, the risk of vector borne diseases increases. Environmental Hazard Valley Fever (coccidioidomycosis): Valley Fever is an illness caused by breathing in a fungus which lives naturally in the soil in San Luis Obispo County. When the soil is disturbed – by wind, construction, or everyday activities such as biking or gardening – people can breathe in the spores from this fungus and develop Valley Fever. Most people who become infected with Valley Fever (60%) do not experience any symptoms and do not need treatment. Around 30%-40% of people develop flu-like symptoms such as severe fatigue, cough, fever, heavy sweating at night, loss of appetite, muscle and joint aches, and sometimes a rash. A small percentage experience a much more serious form of the disease in which the infection spreads throughout the body. People who experience this serious form of Valley Fever are at risk of dying from complications of the disease and may need to take medication for the rest of their lives. Valley Fever is more common among older adults, though anyone of any age can contract it. Several groups of people are at higher risk for developing the severe forms of Valley Fever, including African Americans, Filipinos, women in the third trimester of pregnancy, and people with weak immune systems. According to the County of San Luis Obispo Public Health Department, Valley Fever appears to be on the rise in recent years, with 2017 bringing the highest number of recorded cases on record to California. A March 2013 Morbidity and Mortality Weekly Report published by the Centers for Disease Control and Prevention (CDC) and referenced in the 2018 California State Hazard Mitigation Plan notes that more than 20,000 cases of Valley Fever are reported each year in the United States, but many more cases likely go undiagnosed. Some researchers estimate that each year the fungus infects more than 150,000 people, many of whom are sick without knowing the cause or have symptoms so mild they are not recognized. Prevention: Persons can limit their risk of Valley Fever by taking steps to avoid breathing dirt and dust in the air, avoiding dusty areas, dampening soil to prevent it from drifting in the air, staying inside and sealing windows during dust storms, and closing car windows and setting air conditioners to recirculate while driving on dust-filled roads. Mosquito-Borne Illness: Mosquito-borne viruses belong to a group of viruses commonly referred to as arboviruses. Although 12 mosquito-borne viruses are known to occur in California, only West Nile Virus, Western Equine Encephalomyelitis (WEE) virus and St. Louis encephalitis (SLE) virus are significant causes of human disease. West Nile continues to seriously affect the health of humans, horses, and wild birds throughout the state. As of 2019, San Luis Obispo County does not provide mosquito abatement services. Zika virus has been found in California, but according to the California Department of Public Health, Zika infections in the state have mainly been reported in people who were infected while traveling in areas outside of California with ongoing Zika transmission. As of 2019, there are no records of local transmission of Zika anywhere in California. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-96 Prevention: The CDC recommends insect repellant, covering exposed skin and making sure mosquitoes stay outdoors as methods of preventing insect bites and disease transmission. Lyme Disease: Lyme disease is transmitted by the western black-legged tick. Lyme disease was first described in North America in the 1970s. Though the tick has been reported in 56 of the 58 counties in California, the highest incidence of the disease occurs in the northwest coastal counties and northern Sierra Nevada counties with western-facing slopes. According to the California Department of Public Health, San Luis Obispo County is in an area where the western black-legged tick is commonly found; however, Lyme disease cases are not common or go unreported. Prevention: Risk factors for Lyme disease include spending time in wooded or grassy areas, having exposed skin and not removing ticks promptly and properly. Prevention techniques include covering up, using insect repellents, checking clothing, yourself, children and pets for ticks, and removing a tick as soon as possible with tweezers. Geographic Area Disease outbreaks usually occur in densely populated areas, where person to person proximity provides ample opportunity for transmission of illnesses. Places of work and business, schools and high- population public spaces are of particular concern when the threat of transmissible illness occurs. Vector-borne illness are concentrated around the vector they are transmitted by: the risk of Lyme disease is highest in wooded areas, and mosquito-borne illnesses are most prevalent around standing water. Due to its prevalence in the soil across the county, Valley Fever is of concern throughout the planning area. Extent (Magnitude/Severity) The diseases with the potential to have the most impact is novel influenza and pandemic flu, which has the potential for high morbidity (infected) and mortality (fatality) rates. This could include treatment and hospitalization of hundreds or more depending on the severity of the outbreak. Previous Occurrences The Community Health Assessment published in July 2018 provides historical disease counts in San Luis Obispo County between 2010 and 2017. West Nile Virus: The Community Health Assessment notes that statewide, cases of West Nile virus rose from 442 in 2016 to 516 in 2017; while the last reported case of the virus in the county occurred in 2016, West Nile continues to be present in the county, as testing of dead birds has confirmed. Lyme Disease: There were 11 reported cases of confirmed Lyme disease among San Luis Obispo residents from 2006-2015, or an incidence rate of 0.4 per 100,000 population. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-97 Valley Fever: The following figure notes Valley Fever cases in San Luis Obispo County from 2010–2017. According to the CDC, while the reasons for the increased incidence in Valley Fever in 2016 are not known, climatic and environmental factors favorable to Valley Fever proliferation and airborne release might have contributed, including rainfall after several years of drought and soil disturbance resulting from construction. The UC Davis Valley Fever Center attributes the increase in cases to drought conditions and firefighting equipment stirring up fungus in the soil. Foodborne Illnesses: In San Luis Obispo County in 2017, reported cases of foodborne illness included 72 cases of campylobacter, 16 cases of E. coli, no cases of listeria, 29 cases of salmonella, and 8 cases of shigella. While it is possibly the most common cause of gastrointestinal disease, data is not available for norovirus as health care providers are not required to report it to the Public Health Department. Antibiotic Resistant Microorganisms: The CDC reported in 2016 that for the first time, researchers have identified a person in the United States carrying a bacteria resistant to antibiotics of last resort, an alarming development that could mean the “end of the road” for antibiotics. Probability of Future Occurrences The potential exists within the entire county and in all regions of the U.S. for an outbreak of an infectious disease to occur that would dramatically affect the health and safety of the general public and the economy of the affected area, state and possibly nation. The County of San Luis Obispo Public Health Department has been proactive in its infection control surveillance efforts and in its emergency preparedness planning activities. The San Luis Obispo County Community Health Assessment notes annual recurrence in cases of Valley Fever and Lyme Disease between 2010 and 2017, or a 100% annual recurrence rate. For Lyme Disease, the Assessment notes cases in 2011-2017 (none reported in 2010), or an 87.5% chance of recurrence per year. Foodborne illnesses are an annual occurrence in the county. Valley Fever Cases, San Luis Obispo County, 2010-2017 368 257 225 13 5 102 82 55 33 2010 201 1 20 1 2 2013 2014 20 1 5 2016 2017 Source: County of San Luis Obispo Public Health Department ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-98 No known cases of Zika Virus transmission have been recorded in the county or the State of California, though once case of travel related Zika was reported in the county in 2016; this constitutes a 0% recurrence interval. The Community Health Assessment notes that nationally, it is estimated that 5% to 20% of the population is infected with influenza, though rates of infection vary among age groups. The Assessment also notes that between 2000 and 2010, an average of 43 deaths per year occurred in San Luis Obispo County with a primary cause of influenza or pneumonia. The greatest ongoing concern national health agencies have is the potential emergence of a novel influenza virus as recently occurred with the 2009 H1N1 pandemic. For the past several years, federal, state and local governments have been actively engaged in pandemic influenza preparedness planning efforts. The County of San Luis Obispo Public Health Department has an up-to-date Pandemic Influenza Plan and Medical Countermeasure Plan. While influenza is an unpredictable virus, these preparedness measures will facilitate prevention, early detection and treatment when the next pandemic does strike. Globally, an average of three pandemic influenza outbreaks have occurred per century over the past 300 years. Climate Change Considerations Climate change will likely affect vector-borne disease transmission patterns. Changes in temperature and precipitation can influence seasonality, distribution, and prevalence of vector-borne diseases. A changing climate may also create conditions favorable for the establishment of invasive mosquito vectors in San Luis Obispo County, and dry conditions have the potential to exacerbate prevalence of Valley Fever. Vulnerability General Property Historically, naturally occurring biological agents and vector-borne illnesses do not have a direct impact on general property. People The health of the general public is the main impact from naturally occurring biological agents. Each disease has its own morbidity and mortality rates, as well as various rates and vectors for transmissibility. Specific impacts of diseases profiled in this section are included in the Hazard/Problem Definition section. As a worst case scenario, the most notable pandemic influenza outbreak was the 1918 Spanish Flu that was responsible for 20 million to 40 million deaths throughout the world. In 2009, a pandemic of H1N1 influenza, popularly referred to as the swine flu, resulted in many hospitalizations and deaths. Social Vulnerability The areas of the county that have the highest overall social vulnerability, based on the SoVI data discussed and presented in subsection 4.4.1, will also be the most vulnerable to the effects of naturally occurring biological agents and pandemics. Outreach and public education efforts related to these hazards should be focused on the communities that are among the highest social vulnerability in the county. Critical Facilities and Infrastructure ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-99 While biological agents and vector-borne illnesses would not have direct structural impacts on critical facilities and infrastructure, the potential exists for impacts to critical facility and infrastructure operation. A widespread disease and any associated social distancing could cause absenteeism at the workplace. Disease and illness could also cause pressure on the county’s public health system, with an outsized number of patients seeking treatment and the potential for a diminished number of health care workers to meet the demand. Economy Disease mainly has an impact on economic drivers, including commerce. The risk of disease exposure may cause consumers to avoid brick and mortar establishments, though e-commerce may not be as affected. Social distancing put in place to limit exposure to and spread of disease may also impact workplace efficiency, as people stay home and away from public places. Additionally, tourism may be impacted in affected areas. Historic, Cultural, and Natural Resources By and large, impacts from naturally occurring biological agents are focused on people; biological agents would not have an adverse impact to historic, cultural or natural resources. Future Development No impacts to future development are expected from this hazard. Risk Summary • San Luis Obispo County and its population is vulnerable to a variety of different naturally occurring diseases • Ongoing Public Health surveillance and emergency preparedness planning activities are geared towards minimizing the likelihood and reducing the severity of such an occurrence • While the greatest impacts in the county from disease occur to populations, secondary impacts include reduced workplace efficiency and effects on the tourist trade • Past and recent history dictates that the most likely microorganism to be involved in a local epidemic or global pandemic is the influenza virus; antibiotic-resistant microbes are also a grave concern • Due to an increasingly global marketplace for food products, occurrence of significant foodborne outbreaks is also on the rise • The continued absence of a Vector Control District within San Luis Obispo County delays the detection of vector borne disease such as plague, tularemia and West Nile Virus • Vector-borne illnesses can especially be impacted by environmental factors, including drought • Due to the multiple biological agents referenced in this section, defining a single significance and probability rating for this hazard is difficult; scores in the Hazard Risk Summary table below are based on an outbreak of novel pandemic influenza, likely the worse-case scenario in the county. An overall significance of Medium is assigned to account for the lower probability of this event. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-100 Table 5-31 Biological Agents Hazard Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Extensive Occasional Critical Medium City of Arroyo Grande Extensive Occasional Critical Medium City of Atascadero Extensive Occasional Critical Medium City of Grover Beach Extensive Occasional Critical Medium City of Morro Bay Limited Unlikely Negligible Low City of Paso Robles Limited Limited Unlikely Low City of Pismo Beach Limited Likely Limited Medium City of San Luis Obispo Extensive Occasional Critical Medium Avila Beach CSD Limited Unlikely Negligible Low Ground Squirrel Hollow CSD Limited Unlikely Negligible Low Heritage Ranch CSD Limited Unlikely Negligible Low Los Osos CSD N/A Nipomo CSD Limited Occasional Negligible Low San Miguel CSD Significant Occasional Critical Medium San Simeon CSD Significant Unlikely Negligible Low Templeton CSD Limited Unlikely Negligible Low Cayucos Sanitary District Limited Unlikely Negligible Low Port San Luis Harbor District Extensive Unlikely Catastrophic Low San Luis Obispo FCWCD Extensive Occasional Critical Low South San Luis Obispo Sanitary District Limited Unlikely Negligible Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-101 5.3.7 Coastal Storm/Coastal Erosion/Sea Level Rise Hazard/Problem Definition Coastal Storm: Coastal storms are characterized by offshore storm systems that make landfall, bringing high winds, rain, and storm surges to the coastline (USGS 2018). They originate from the combination of low-pressure systems offshore that circulate counterclockwise with high-pressure systems that blow in one direction over a long period of time, which creates a phenomenon of rising water, resulting in massive waves beyond the normal movement of tides. Coastal storms may have hurricane-force winds and cause damage similar to that of a hurricane; however, they are not classified as such because they do not originate in the tropics. The destructiveness of a coastal storm depends on the duration, wind speeds, and tidal factors, with particularly severe potential for damage where strong storm-generated waves coincide with high tides or King Tides (exceptionally high tides that occur once or twice a year). Such storms can exacerbate beach and cliff erosion and increase risks of bluff failure or flooding in low-lying areas. They have the greatest impact on the coastline and coastal communities in the form of beach and cliff erosion which can expose bluff top structures or facilities to bluff failure or landslides, and flooding of low-lying communities due to storm surges and wave energy. During such events, property and infrastructure in unprotected low-lying areas can be damaged by wave attack or flooding, and evacuation routes can become inaccessible. When coastal storms coincide with high tides, as well as during El Niño years, coastal erosion and flooding hazards substantially increase (Russell & Griggs 2012). Figure 5-32 Coastal Storm Damage at Pismo Beach, 1982/83 El Niño Coastal storms can severely damage coastal development and substantially erode the shoreline, especially when they coincide with El Niño years; the 1982/83 El Niño-related storms destroyed coastal structures at Pismo Beach, damaging the Pier, RV park, access trail, and seawall; incurring an estimated replacement cost of over $5.5 million in Pismo Beach alone (in 2019 dollars) (Dean et al. 1984). Photo credit: Lance Nix Coastal Erosion: Coastal erosion refers to the natural geological process resulting in loss of sand, sediment, vegetation, or soil on beaches, dunes, bluffs, or cliffs along the coast caused by the wave attack, winds, tides, coastal storms, and the gradual movement of tectonic plates. Coastal erosion takes place gradually over decades to thousands of years, or may occur rapidly, as with landslides or severe storms. Coastal erosion processes are highly complex and depend on a number of factors such as geologic formation, groundwater seepage, and exposure to wave energy. The 100 miles of San Luis Obispo County coastline are variable in terms of geologic composition and exposure to high tides, wave energy and ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-102 related erosion. Sections of the coast exhibit a variety of backshore landforms including wide sand and cobble beaches backed by cliffs, sandy beaches backed by sand dunes, secluded and undeveloped pocket beaches, rocky intertidal areas, rocky bluffs, and loosely consolidated bluffs. Due to these various backshore types along the shoreline, erosion characteristics also vary significantly. Driven by rising sea levels, large storms, flooding, and powerful ocean waves, erosion wears away the beaches and bluffs along shorelines. Beach and dune erosion occur through high wave run-up during high tides and increased wave energy that carry sand away from the shoreline. Beach and dune erosion may occur gradually over time as beaches naturally accrete and erode, resulting in mild changes in the shoreline and volume of sand present on the beach (Hapke et. al 2006). Energetic coastal storms and particularly strong El Niño events potentially result in the abrupt loss of large quantities of sediment and increased landward retreat of the shoreline. Coastal bluff erosion also occurs in the form of irreversible landward retreat of coastal bluffs and cliffs (Griggs 2003). Historical bluff erosion has been episodic in nature with rates that vary throughout San Luis Obispo County due to the composition of coastline bluff rock formations and vulnerability to wave interaction with the cliffs. Rising tides, currents, and waves directed at the base of the bluff cause the erosion of relatively non-resistant rock. As a bluff erodes, the top edge moves landward. This is a natural process that becomes a hazard as it threatens structures or other developed property, infrastructure, as well as recreational trails and public coastal access. The retreat of the bluffs threatens waterfront residences, businesses, and public facilities, eventually rendering them uninhabitable or unusable. Human alteration of the shoreline can influence long and short-term erosion rates. One of the major causes of beach erosion is the construction of dams and other structures along creeks and rivers that trap sediment and prevent it from reaching the ocean. This deprives the shoreline of the material that would replenish beach sand supplies. Coastal structures such as groins, jetties, seawalls, and breakwaters can also alter littoral drift. Beach groins and breakwaters, for example, can trap littoral sand and build beaches over a limited area; but by doing so, they reduce the amount of sand that flows to down-current beaches. This can result in a rapid loss of beach sand in down-current beaches. Seawalls are often used to protect seacliffs from eroding wave action. These structures, however, can reflect wave energy to strip protective beach sand at an accelerated rate. This may ultimately result in increased seacliff erosion rates, particularly at sections of coastline adjacent to the seawall. Sea Level Rise: Sea level rise is defined as the relative average rise in mean sea level. Global sea level rise refers to the long-term gradual increase of sea levels driven by the expansion of ocean waters as they warm, the addition of freshwater to the ocean from melting land-based ice sheets and glaciers, and extractions from groundwater. Regional and local factors such as tectonics and ocean and atmospheric circulation patterns result in relative sea level rise rates that can be higher or lower than the global average. Sea level rise also contributes to increased coastal flooding and more frequent and severe tidal inundation. This can exacerbate existing coastal hazards from severe storms, as well as accelerate coastal beach and bluff erosion. Unlike coastal flooding caused by coastal storms, tidal inundation when combined with sea level rise would occur with predictable high tides and with some regularity. Existing low-lying coastal areas are expected to be semi-permanently or permanently inundated resulting from unabated global climate change and resulting sea level rise. Sea level rise is anticipated to contribute to increased coastal hazards including coastal storms and coastal erosion (County of San Luis Obispo 2019a). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-103 Geographic Area The entire 100-mile coastline of San Luis Obispo County and existing urban development and natural resources are potentially exposed to a range of coastal hazards, including coastal storms and coastal erosion. Such hazards are projected to become more severe when combined with sea level rise (County of San Luis Obispo 2019a). The creeks and rivers that drain inland mountains in confluence with the Pacific Ocean result in an ecologically diverse range of low-lying habitats including bays, inlets, and coastal wetlands. Additionally, bluffs and dunes line much of the County’s coast, including the cities of Grover Beach, Pismo Beach, and Morro Bay. The coastline also includes five large unincorporated communities served by Community Services Districts (CSD): Avila Beach, Los Osos, Cambria, Oceano, and San Simeon; and extensive rural areas (County of San Luis Obispo 2019b). These areas contain a number of popular recreational beaches such as Pismo Beach, Morro Bay, Cayucos and Moonstone, along with visitor-serving uses, developed and undeveloped coastal bluffs and trails, two harbors (Morro Bay and Port San Luis), and a large dune field ranging from the Pismo Dunes through the Guadalupe Dunes. Low-lying portions of Highway 1, an officially designated State Scenic Highway, which has been damaged by past bluff erosion, also extend along the coastline. Designated State Parks in the San Luis Obispo Coast District include Cayucos State Beach, Estero Bluffs State Park, Los Osos Oaks State Reserve, Montana de Oro State Park, Morro Bay State Park, Hearst San Simeon State Park, and W.R. Hearst Memorial State Beach (Department of Parks and Recreation 2019). A summary of hazard potential by jurisdiction or urban area within the county are provided in Table 5-32 below. Table 5-32 Hazard Potential of Jurisdictions and Urban Areas within the San Luis Obispo County Coast Jurisdiction or Urban Area Primary Characteristics and Vulnerabilities City of Grover Beach • Sandy beaches backed by low sand dunes covered with dense vegetation • Commercial, residential (i.e. mobile homes) and recreational (golf course) development • Active erosion of beaches and dunes, impacts to low-lying coastal recreational uses, commercial and residential structures City of Morro Bay • Wide sandy beaches and large sand dunes backed by residential and commercial development on higher elevated terraces • Includes low-lying development, lagoons, trails, and saltwater marsh • Active erosion of beaches and dunes, low-lying areas susceptible to projected sea level rise • Erosion and landward retreat of bluffs City of Pismo Beach • Topography varies from sandy beaches and sand dunes to cliffs and bluffs ranging from 10 to 100 feet in height • Commercial and residential development close to the shoreline • Parks on top of bluffs include Dinosaur Caves Park with trails and a playground; Chumash Park; Monarch Butterfly Grove • Erosion of beaches and dunes; erosion and landward retreat of bluffs threaten residential, commercial, and recreational development • Development close to the shoreline vulnerable to coastal hazards and sea level rise ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-104 Jurisdiction or Urban Area Primary Characteristics and Vulnerabilities Avila Beach CSD • Southerly-facing wide sandy beach backed by development including Avila Beach Park, commercial and residential development, and overnight accommodation • Avila Beach beaches and recreational Pier protected from northerly swells by the Point San Luis Breakwater • Erosion of the sandy beach threatens low-lying commercial, residential, and recreational development Los Osos CSD • Sand dunes and scenic bluffs of the Los Osos Oaks State Natural Reserve • Active erosion of sand dunes and bluffs • Low-lying development in downtown Los Osos threatened by projected sea level rise, and inundation from coastal storms and flooding San Simeon CSD • Low cliffs and rolling coastal hills of the Hearst San Simeon State Park1 • Supports low-lying areas of Highway 1 with little to no coastal development • Erosion of low cliffs, coastal bluff retreat Cayucos • Varies from narrow sandy beaches backed by undeveloped bluffs and sea cliffs; to wider sandy beaches backed by relatively low-lying coastal development • Erosion of bluffs and sea cliffs, active erosion of narrow sandy beaches • Sea level rise and coastal hazards threaten low-lying commercial and residential development Port San Luis Harbor District • Port San Luis Pier, Boat Yard, and RV Campground backed by 100-foot high cliffs which descend eastward to lower elevations • Southerly-facing beach protected from northerly swells by the Port San Luis breakwater • Erosion of 30 to 100-foot high cliffs, coastal bluff retreat • Sea level rise and coastal storms threaten Port San Luis Pier, Boat Yard, and campgrounds Cambria • Rocky shoreline with some areas of narrow beaches backed by low cliffs approximately 20-50 feet high • Bluff top residential development and pubic open space such as the Fiscalini Ranch Preserve • Bluff retreat, active erosion of sandy beaches • Projected sea level rise and accelerated bluff erosion threaten bluff top residential development Oceano • Wide sandy beaches backed by low active dunes, residential development and campgrounds • Popular for beach and dunes for off road vehicle use • Active erosion of sandy beaches and dunes Coastal Storms, Coastal Erosion, and Sea Level Rise by Area The reported rates of erosion presented in the following sections approximate future coastal erosion rates and vulnerability due to difficulties in obtaining accurate erosion data. San Luis Obispo County: The San Luis Obispo County coastline has the potential to be significantly impacted by coastal storms. Bluff erosion resulting in landward retreat of the seacliffs and beach erosion ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-105 may result in landward retreat of the shoreline and impacts to coastal development and infrastructure. Low-lying areas often located by coastal streams or estuaries are vulnerable to inundation, wave run-up and flooding associated with projected sea level rise. California’s Fourth Climate Change Assessment notes that periodic El Niño events exert a dominant control on coastal hazards across the region, driven by seasonally-elevated water levels as high as 30 cm (11.8 inches) above average, and, on average, 30 percent larger winter wave energy in California (Langridge et al. 2018). Past El Niños, including the extreme 1982-83 and 1997-98 events, caused significant erosion along the Central Coast due to the elevated winter waves and water levels, but impacts were more acute along the southern ends of littoral cells due to the more southerly wave approaches driving sand to the north (Langridge et al. 2018). Further, the large El Niño event of 2015-16, one of the three largest in the historical record, resulted in winter wave energy that was over 25 percent larger than a typical winter along the Central Coast and caused substantial acceleration of beach erosion (State of California 2018). City of Grover Beach: Grover Beach is fronted by sandy beaches backed by low active dunes that are covered with dense vegetation, backed by a golf course, a mobile home park and Highway 1. The sandy beaches provide structures with moderate protection from storm waves. Timber beach access ramps were damaged, however, during the winter storms of 1983. The Grover Beach shoreline is classified as a “moderate risk” with respect to possible coastal damage incurred by storm waves. City of Morro Bay: The Morro Bay coast is fronted by large sand dunes from Atascadero State Beach and continuing south through much of Montaña de Oro State Park that provide protection for developments located on terrace materials behind the sand dunes. Due to the construction of the Morro Bay Harbor Breakwater and the presence of Morro Rock, the littoral drift north of Morro Bay is interrupted and the coast has extended seaward. The beach has widened about 250 feet near San Jacinto Avenue and almost 500 feet in front of Morro Bay High School in the past 50 years. This sandbar protects development in this region. The bay is protected by the sandspit south of Morro Rock that provides a barrier to wave attack that would otherwise impact the developed areas along the Embarcadero. Portions of Morro Bay are low- lying and are classified as a “high risk” with respect to possible future coastal flooding associated with sea level rise. City of Pismo Beach: Cliffs and bluffs ranging in height from ten to one hundred feet exist along approximately five miles of the northwest portion of the city shoreline, with the southern areas of the city around the Pismo Beach Pier being low-lying. Bluff erosion rates in Pismo Beach vary from an average of 2 inches per year where bedrock is present to up to 12 inches per year in areas with limited bedrock (City of Pismo Beach 2002). Past studies have found that more than 60 homes are within the bluff retreat hazard zone and may be subject to damage or destruction by 2100, without accounting for accelerated bluff retreat associated with sea level rise (City of Pismo Beach 2002). Portions of Pismo Beach are either low-lying or are located atop eroding coastal bluffs and are classified as a “moderate risk” with respect to possible future coastal flooding or accelerated bluff retreat associated with sea level rise. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-106 Figure 5-33 Bluff Erosion and Overlying Development at Dinosaur Caves Park in Pismo Beach, January 2010 Residential structures situated adjacent to coastal bluff cliffs are vulnerable to the impacts of coastal storms and actively eroding bluffs. Irreversible bluff erosion exacerbated by future sea level rise has the potential to damage communities such as those in Pismo Beach (January 2010). Source: San Luis Obispo Tribune 2010. Avila Beach: Avila Beach is a southerly-facing sandy beach backed by areas of low-lying coastal development in the north along San Luis Creek including commercial and residential uses, hotels and Avila Beach Park, as well as homes atop a 10-35 foot high low coastal bluff. Although most of Avila Beach is protected by 10 to 20-foot-high seawalls, low-lying areas to the north including Avila Park, and coastal access parking are potentially exposed to wave run-up and flooding. Avila Beach is partially sheltered from northerly swells by the Point San Luis Breakwater but is vulnerable to coastal storms originating from the southwest. The 1983 El Niño event severely damaged the recreational pier at Avila Beach. Low-lying areas of Avila Beach are classified as a “moderate risk” with respect to possible future coastal flooding associated with sea level rise. Los Osos-Baywood Park: The community of Los Osos-Baywood Park is located a hillside and low-lying areas of the shoreline of Morro Bay. The sand dunes of Morro Bay State Park sandspit and Park currently protect the community of Los Osos from potential wave hazards, although dozens of homes along the shoreline of Morro Bay are constructed just above sea level. The low-lying shoreline areas of this community along Morro Bay may have low to moderate risk with respect to future coastal flooding from sea level rise over the long term. It is unknown if sea level rise could eventually erode or lead to breaches in the sand dunes along Morro sandspit or to what extent such a breach could affect coastal flooding in Los Osos-Baywood Park. San Simeon: San Simeon is fronted by a narrow sandy beach backed by low coastal bluffs that support several bluff top homes and a hotel with minimal setbacks and the town’s wastewater treatment plant, which is protected by a low rock revetment. These bluff top uses are currently exposed to moderate risk and may be threatened in the near term if bluff retreat rates accelerate with sea level rise. Such threats would be considered medium or high with projected sea level rise and potential accelerated bluff retreat. Cayucos: The shoreline in Cayucos generally supports narrow beaches backed by low cliffs approximately 20 feet-high as well as a low-lying downtown area by Cayucos Creek, much of which is protected by low rock revetments and a low seawall. Over 100 residences with minimal setbacks from the edge of the bluff are potentially exposed to coastal erosion hazards, although a number are protected by rock revetments or seawalls. In the winter month the sandy beach often erodes, and waves strike directly against the ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-107 bluffs. The Cayucos shoreline faces south such that its beaches are partially protected from northerly swells. Wave action in this area is still significant. The seacliffs are comprised of Franciscan melanges, characterized by blocks of rocks often surrounded by small zones of sheared or crushed rock that tend to erode easily. Some zones contain more erosion resistant rock blocks that have been exposed as the weaker blocks have eroded away. During the intense storm waves of 1983, these resistant blocks were breached at some spots. As a result, the bluff receded as much as 20 feet (San Luis Obispo County 1999). Figure 5-34 Low-lying Residential Development Fronted by Sandy Beaches in Cayucos Cayucos shoreline residential development is typically fronted by a wide sandy beach that protects development from coastal storms and sea level rise; however, the beach provides limited protection from potentially severe coastal storms and associated wave run-up and flooding. Rates of erosion are highly variable along this coastline and range from 6 to 10 inches per year. Emergency rip-rap and numerous seawalls were constructed in response to the storm waves of 1983 (San Luis Obispo County 1999). Downtown Cayucos is another area of concern. Built upon the unconsolidated sediment deposited from the Cayucos creek, this area is susceptible to shoreline erosion. During rainy months when the ground becomes wet, the low permeability of the clays tends to perch or elevate the groundwater table. Consequently, the saturated soils cause increased erosion due to slope instability and slumping of the seacliff face. Therefore, much of Cayucos is either low-lying around the downtown or includes bluff top homes with minimal setbacks and is therefore classified as “moderate to high risk” with respect to both existing coastal hazards and possible future coastal flooding and accelerated bluff retreat associated with sea level rise. Port San Luis: Port San Luis and the coastline surrounding San Luis Bay is well-protected from the dominant northwesterly swells by the 2,300-foot long Port San Luis breakwater, though little protection is offered from southerly swells. The Port San Luis area is backed by 100-foot high cliffs that descend eastward into approximately 30-foot high cliffs. A rock revetment protects Avila Beach Drive from Port San Luis toward Avila Beach from storm waves and bluff erosion. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-108 Historic storms have shown that both Port San Luis and Avila Beach are susceptible to coastal damage resulting from storm waves, especially those generated from southerly swells. Winter storm waves during 1983 El Niño-related coastal storms, for example, damaged the concrete seawall that runs parallel to Front Street. This region is classified with a “moderate risk” with respect to possible coastal damage incurred by storm waves. Cambria: Cambria is characterized by rocky intertidal shoreline and narrow beaches backed by low cliffs approximately 20 to 40 feet high. This section of coastline is subject to moderate to heavy wave action, mostly from northerly swells. The coast in the area is comprised of a rock unit called the Cambrian slab that is a local, colloquial name for the Cretaceous-age sandstones that form the resistant rock headlands in the area. Since this type, of sandstone is fairly resistant to erosion, seacliff retreat rates in Cambria are relatively low when considering the wave energy imposed on this area. However, while some coastal bluff top homes are protected by rock revetments, dozens of homes along the coastal bluff tops have minimal setbacks and are currently threatened by erosion by wave action and current sea cliff erosion rates of two- to three- inches per year. Figure 5-35 Low Coastal Bluffs and Residential Development in Cambria The San Luis Obispo coastline is diverse in geologic composition and subject to variable coastal hazard impacts. Urban development adjacent to coastal bluffs are highly vulnerable to irreversible bluff erosion, such as those in Cambria in close proximity to the shoreline (pictured above). All developed coastal areas of Cambria are in high hazard zones (USACE 2016). Much of the shoreline of Cambria includes bluff top homes with minimal setbacks and scattered rock revetments is therefore classified as “moderate to high risk” which would increase with respect to possible future accelerated bluff retreat associated with sea level rise. Shell Beach: The coastline from Fossil Point proceeding eastward to Shell Beach is characterized by offshore rocks and sea stacks backed by 30-to 100-foot eroding cliffs. Seacliff retreat rates range from 4 to 7 inches per year for the Shell Beach coastline; catastrophic rock fall is an important agent of erosion in this area. Although many homes located adjacent to the coastline of Shell Beach are protected by seawalls, bulkheads, sandbags, and rip rap, this stretch of coastline is characterized as “high risk” with respect to possible erosion. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-109 Oceano: Oceano is generally fronted by wide sandy beaches backed by low active dunes. These dunes provide protection for structures located nearby; however, they are subject to erosion during storm surges at extreme high tides. Although these sand dunes protect dwellings from storm waves, the winter storms of 1983 damaged structures and destroyed timber ramps that provided vehicular beach access. Therefore, this region is characterized with a “moderate risk” and a “high risk” region adjacent to the Arroyo Grande Creek mouth with respect to coastal erosion. South County: The coastline from Oceano southward to the San Luis Obispo/Santa Barbara County line is described as “sandy beaches backed by active dunes with sparse vegetative cover, high intermediate old dunes with vegetative cover, marshes, and lakes” (San Luis Obispo County 1999). Although the dune face is wave-cut and experiences frequent slides, this region is classified with a “moderate risk” with respect to coastal erosion. Extent (Magnitude/Severity) All low-lying coastal areas within San Luis Obispo County including beaches are exposed to coastal storm hazards that would be subject to inundation with projected sea level rise. Increased frequency, severity, and duration of high tide and storm events related to climate change may also result in more frequent and severe storm events along the coast. Coastal Storm: Coastal storms can cause high winds and strong storm surges that would affect low-lying “vulnerable” coastal resources and infrastructure located in urban areas such as Morro Bay. For wind hazards, the extent of wind speeds can range from tropical depressions (less that 35 kts), tropical storms (35-65 kts) to hurricane force winds are 65kt or greater. Low-lying areas susceptible to wave run-up and coastal flooding due to coastal storms are often protected by seawalls or revetments. These protective structures may be breached during a severe coastal storm, however, such as those associated with El Niño years and/or a 100-year coastal storm event. Wave runup elevations are used in coastal flood studies to determine flood hazard areas for sites along the open coast that are subject to direct assault by deep- water waves. Runup elevations range with location and local beach slope. Wave runup elevations for the 1% annual chance coastal storm range from 11 to 24 feet above Mean Sea Level depending on location; the 0.2 % annual chance wave runup elevations range from 17 to 30 feet, but generally are around 22 feet above Mean Sea Level. Actual depth of inundation would vary, depending on the ground elevation at a particular site. Areas with ground elevations 3 feet or more below the 1% annual chance wave runup elevation are subject to velocity hazard, shown as the VE zone on FEMA flood hazard maps. More details on specific sites can be referenced in the County’s 2012 Flood Insurance Study (FEMA 2012). Coastal development on coastal bluffs and cliffs that are not susceptible to direct wave run-up and flooding are vulnerable to coastal storms and the resultant bluff erosion. All coastal development in proximity to the shoreline is threatened by landward retreat of the shoreline due to beach and bluff erosion, which are exacerbated by coastal storm events. Coastal Erosion: Coastal erosion threats include both dune erosion and bluff erosion, and can result from storms, sea level rise, strong wave action, and human activities. Unlike coastal storms, cliff erosion can result in permanent and significant alterations of coastal geology that can expose landward development and resources to additional coastal threats. Large sections of the county coastline, especially those with rocky headlands or sea cliffs, are not vulnerable to flooding, but are highly susceptible to erosion (Heberger et. al 2009). Areas vulnerable to impacts of coastal beach erosion within the county include low-lying areas fronted by sandy beaches and dunes, including sand dunes at Pismo State Beach, Oceano, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-110 and Los Osos. Impacts of coastal bluff erosion affect development above or adjacent to coastal cliffs and bluffs, including bluff top residential development in Cambria, Shell Beach, Pismo Beach, and the cliffs at the Point San Luis Lighthouse. Erosion extent can range from gradual wearing away of coastal land at inches per year to more significant, catastrophic events that can result in bluff failures involving several hundred cubic yards of material. Sea Level Rise: Low-lying coastal areas such as those in Morro Bay, Oceano, Cayucos and portions of Avila Beach are more susceptible to wave run-up and flooding in combination with sea level rise than structures atop coastal cliffs; however, such bluff top structures may be threatened by accelerated bluff erosion induced by projected sea level rise. Projected sea level rise in Morro Bay may increase threats to low-lying habitats or development relative to current sea level conditions). Further, as noted above, sea level rise may lead to accelerated coastal bluffs retreat and erosion that may exacerbate threats to communities located along the cliffs and close to the coast such as Pismo Beach, Shell Beach, Avila Beach, Morro Bay and Cambria. Projected sea level rise may exacerbate saltwater intrusion into coastal aquifers potentially affecting water supply of some communities. Sea level rise may also exacerbate the frequency and depth of inundation of coastal marshland, leading to its conversion to open water or mudflat habitat. This in turn can increase the concentrations of brackish water that can compromise coastal marshland habitat integrity. Specific to sea level rise, the extent of anticipated rise for the purposes of this plan is modeled for three different scenarios generally ranging from 1 ft, 3 ft, and 10 ft; this is described in more detail in the Vulnerability subsection; maps showing potential inundation from the three sea level rise scenarios are included in the jurisdictional annexes for Avila Beach, Cambria, Cayucos, Grover Beach, Los Oso, Morro Bay, Oceano, Pismo Beach, San Simeon and South San Luis Obispo County Sanitation District. Previous Occurrences Coastal Storm: Increased coastal erosion and flooding from intense storm activity along the California coast occurred during major El Niño events of 1982/83 and 1997/98 (Bromierski 2003). High tides and severe storm waves during the El Niño storm in March 1983 damaged the concrete seawall in Port San Luis as well as development within the community of Avila Beach (the wide sandy beach eroded and was not sufficient to protect urban development from severe storm waves). Housing developments in this area experienced landslide activity as well as cracking of foundations and roads. The Union Oil Pier at Avila Beach was also severely damaged, as well as the Avila Beach Pier (Figure 5- 36) (San Luis Obispo County 1999). Historic storms have resulted in substantial damage to coastal regions and demonstrated susceptibility of the coastline to swells originating in both the northwest and southwest. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-111 Figure 5- 36 Union Oil Pier in Avila Beach Collapses Following Severe 1983 Storm A severe coastal storm in March 1983 brought high winds and powerful surf that damaged coastal pier and infrastructure including sections of Highway 1 and destroyed the wooden Union Oil Pier in Avila Beach. Source: San Luis Obispo Tribune 2018. El Niño-related storms cause increased damage to the coastline with heavy rainfall, energetic wave conditions, and accelerated dune and bluff erosion. Such storms are also correlated with increased coastal flooding magnitudes (Andrews et al. 2004). Wave height, sea level, and precipitation, which are the primary external forcing parameters in seacliff erosion, further increase with storm intensity. Significant cliff erosion and storm damage occurred along the central coast of California during the 1982/1983, 1997/1998 and 2015/16 El Niño winters (Table 5-33) (Storlazzi & Griggs 2000). Further data on previous storm occurrences and related impacts to the county are provided in subsection 5.3.1, Adverse Weather. Table 5-33 Recorded El Niño related coastal storms and flooding in coastal communities within the County of San Luis Obispo Storm Event (Year) Primary Area(s) affected Extent of Damage El Niño, Winter 1982/83 Entire County Coastline Heavy rainfall increased coastal flooding and accelerated dune and cliff erosion. Classified as one of the three strongest El Niño storms since 19502. March 1983 Avila Beach, Port San Luis High intensity storm which brought 6-8 inches of rain; high energy surf over a 7-day period destroyed the Union Oil Pier in Avila Beach and seawall in Port San Luis1. El Niño, Winter 1997/98 Entire County Coastline High intensity storm that impacted the coastline with high energy wave conditions, substantial rainfall, and accelerated beach and bluff erosion Classified as one of the three strongest El Niño storms since 19502. El Niño, Winter 2015/2016 Entire County Coastline High wind, rainfall, and energetic waves that accelerated beach and bluff erosion. Classified as one of the three strongest El Niño storms since 19502. 1 Source: (County of San Luis Obispo Public Works Department 2019) 2 Source: (Jan Null 2019; World Meteorological Organization 2019) Coastal Erosion: Coastal erosion within San Luis Obispo County has primarily occurred during periods of intense wave action coinciding with high tides and coastal storms. Local annual beach erosion rates from ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-112 1942 to 2002 (Hapke et. al 2006) range from three inches to over one foot (Table 5-34) (San Luis Obispo County 1999; USACE 2016). Beach erosion of up to 3 feet per year has occurred in areas including Cayucos, Morro Strand State Beach, Morro Bay State Park, Montaña de Oro State Park, Shell Beach, Pismo Beach, and Oceano Dunes. Historical rates may not accurately predict future erosion; however, as substantial erosion can occur during individual severe storms that are expected to be exacerbated by climate change and associated sea level rise. This can result in bluff and cliff collapse (Griggs 2003). Major historical erosion events coincide with heavy storm years including: Piedras Blancas in 2001, the general county coastline in 2010, and Shell Beach and Montaña de Oro in 2017 (Protsman 2018). Reliable estimates of retreat are difficult to obtain because the historical record and the quality of the information is limited relative to ongoing coastal processes (City of Pismo Beach 2002). Dune erosion can either be short term where large coastal storm events and severe wave attack result in loss of sand or cliff failure, or long term with the gradual erosion of the shoreline over time due to onshore winds and high tides. Dune-backed shorelines may also change over time as dunes expand and recede (Hapke, 2006). Specific locations within the County experience differing rates of shoreline change. Long-term shoreline change in the northern section of the county has historically been approximately 0.1 meters (0.32 feet / 3.84 inches) of erosion per year, and short-term change averaged 0.7 meters (2.30 feet / 27.6 inches) of erosion per year. Short-term shoreline changes averaged 3.4 meters (11.5 feet / 138 inches) of erosion per year in the short-term but was relatively stable in the long-term. Pismo Beach is an example of an area vulnerable to cliff erosion, where low bluffs consist of relatively weak sedimentary rock susceptible to wave erosion and undercutting of the cliff. The City of Pismo Beach conducted a Bluff Erosion Study in order to quantify historic erosion rates and evaluate impacts to coastal resources and development. Bluff retreat typically occurs episodically with several feet to several tens of feet of the bluff top eroded during a single season or storm event, while the bluff top in adjacent areas may remain unchanged. This bluff study estimates an approximate average retreat of 4 inches per year over the last 50 years. Retreat rates of only 2 inches per year were observed at relatively resistant south- facing bluffs. Retreat rate of 6 to 12 inches per year, however, were observed in areas with higher instability where there has been sea cave collapse (City of Pismo Beach 2002). Rapid bluff collapse that contributes to higher bluff erosion rates are difficult to predict and projected to increase with sea level rise. For example, an approximate 100-foot section of the Pismo Beach bluff collapsed following the winter storm season in March 2011, a much more rapid erosion rate than those reflected in historical records (Figure 5-37). The historic bluff retreat rates determined in this study did not consider increasing wave energy and sea level rise. Existing rates of annual erosion may only approximate future coastal erosion rates and associated hazard vulnerability. Table 5-34 Historic Rates of Erosion at Specific Sections of the Coastline Location Historic Erosion1 Rate (inches/year) Shoreline Characteristics Cambria 2-3 Narrow beaches backed by low cliffs approximately 20 feet high with urban development and public parkland Cayucos 6-10 Wider beaches backed by low cliffs approximately 20 feet high Morro Bay +602 Large sand dunes backed by elevated terraces along a bay protected by a sandspit ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-113 Los Osos 4-6 Large sand dunes backed by developed areas Port San Luis Not Available Sandy beach backed by cliffs up to 100 feet high, protected from northwesterly swells by the Port San Luis Breakwater Pirates Cove 4-7 Offshore rocks and sea stacks backed by eroding cliffs approximately 30-100 feet high Grover Beach Not Available Sandy beaches backed by low active dunes covered with vegetation, a golf course, and residential development Oceano Not Available Wide sandy beaches backed by low active dunes South County Not Available Sandy beaches backed by active dunes with sparse vegetative cover, high intermediate established dunes with vegetative cover, marshes and lakes. Pismo Bluffs3 2-12 (Average of 4 inches/year) Relatively steep bluffs approximately 20 to 110 feet high fronted by narrow and steep beaches formed by bluff erosion. 1 Historic rates of erosion describe the approximated change in shoreline position and/or bluff retreat calculated over the period from 1942 to 2002, and vary depending on geologic composition and exposure to wave energy (Hapke et. al 2006). 2 Due to the construction of the Morro Bay Harbor Breakwater and the presence of Morro Rock, the littoral drift north of Morro Bay has been interrupted and the coast has extended seaward with increased beach width (San Luis Obispo County 1999). 3 Historical erosion rates of the Pismo Bluffs are based on evaluation of approximately 5 miles of coastline between Harloe Avenue and The Bluffs Drive in Pismo Beach (City of Pismo Beach 2002). Figure 5-37 Bluff Erosion at Pismo Beach, March 2011 An approximate 100-foot section of cliff collapsed in Pismo Beach due to erosion of the bluff following winter storms in March 2011, demonstrating the severe impacts of coastal hazards on weak bluff sediments. Source: San Luis Obispo Tribune 2011 Hard shoreline protective structures (i.e. seawalls, revetments) are implemented in some areas to slow erosion; however, such structures become less effective during severe storms and high tide events. The efficacy of existing protection devices and natural barriers such as typically stable serpentine rock is expected to decrease with projected sea level rise. Substantial beach erosion and cliff collapse resulting from severe storms has occurred along the bluffs adjacent to Pacific Avenue and Studio Drive in Cayucos. Extensive blocks of sheared serpentine that normally serve to slow erosion were breached by intense ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-114 storm waves during a coastal storm event in March 1983. The bluff receded as much as 20 feet, causing severe beach and bluff erosion along the coast and irreparably damaged to coastal infrastructure (San Luis Obispo County 1999). Severe coastal erosion also occurred at low-lying portions of Highway 1 near Piedras Blancas; from just north of the Piedras Blancas Lighthouse to the Arroyo de la Cruz Bridge. The temporary rock revetment armoring the road was not sufficient to protect the road from coastal storm and flood damage, and coastal erosion compromised the safety and structural integrity of the Highway. Approximately 2.8 miles of Highway 1 was relocated up to 475 feet landward in order to prevent coastal bluff erosion from adversely affecting future operation of the highway for the next 100 years (Figure 5-38) (Caltrans 2010). Figure 5-38 Vulnerable Portions of Highway 1 and Realignment near Piedras Blancas Low-lying portions of Highway 1 near are threatened by severe coastal erosion due to wave damage and insufficient protection from hard structures (pictured left). In response, an approximate 2.8 mile-long segment of Highway 1 near Piedras Blancas was realigned 475 feet inland to protect the roadway from future erosion (new roadway completed in 2017, pictured right) (Caltrans 2010). Photo Source: San Luis Obispo Tribune 2014 (left); AP Photo/Danial Dreifuss (right) Sea Level Rise: Sea levels are rising at different rates in different regions of the California Coast due to local differences in tectonic uplift/subsidence and other factors such as nearshore bathymetry. Typically, the highest sea level readings along California’s coastline occur during periods of heavy rain that coincide with high tides, causing coastal flooding, coastal bluff erosion, and cliff collapses such as those experienced during the 1982/83 and 1997/98 El Niño events. The Port San Luis Tide Gauge located on the Hartford Pier reports the local sea level rise rate at approximately 0.93 (+/-0.38) millimeters per year (mm/year) since 1948 (NOAA 2017) (Figure 5-39). This rate compares to the global average annual rate of 3.2mm/year (Griggs et. al. 2017) and near the mouth of San Francisco Bay that has recorded approximately 7 inches in sea level rise variation over the past 100 years. The monthly sea level tide gauge record at Port San Luis was at its lowest recorded level (-0.2 meters or -0.66 feet) in the 1940s and reached its highest measured monthly average in the late 1990s at approximately 0.2 meters (0.66 feet). The growth trend is projected to increase in future years (NOAA 2017). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-115 Figure 5-39 Tide Record and Sea Level Rise Trend from Port San Luis Tide Gauge (NOAA Station 9412110) Source: (NOAA 2019b) Probability of Future Occurrences Coastal Storm: Highly Likely. Coastal storms typically occur every winter season between the months of November and March. Coastal storms vary in frequency and severity and will be exacerbated by rising sea levels and future increase in variation in climate. The Federal Emergency Management Agency (FEMA) estimates and maps future coastal storms based on the 1-percent probability of an extreme storm occurring during any given year (FEMA 2019). Thus, extreme coastal storms occur less frequently. Increasing trends in coastal storm frequency and severity based on climate-related variables have also been identified by studies of cyclone frequency and wave height (see subsection 5.1.3 Climate Change Considerations of the base plan). The future occurrence of coastal storms is projected to increase; however, the projected frequency and intensity is difficult to quantify with current climate science and coastal storm modeling. Coastal Erosion: Highly Likely. Average rates of historic beach and cliff erosion and shoreline retreat and are expected to continue and accelerate, but future erosion rates are difficult to project due to variable coastal processes and uncertainty in sea level rise projections. Increased frequency of coastal storms and wave run-up due to sea level rise increases the irreversible bluff erosion and cliff collapse that may occur. Dunes and cliffs will exhibit differential responses to rising sea levels. The Pacific Institute models projected rates of coastal dune and cliff erosion in its “Erosion hazard with a 1.4-meter (4.6 foot) sea level rise, 2100” dataset, which represents the areas vulnerable to erosion with a sea level rise of 1.4 meters (4.6 feet) by 2100. This data is utilized in a larger study: The Impacts of Sea-Level Rise on the California Coast, which quantifies the projected impacts of coastal dune and bluff erosion (Heberger et. al 2009). This study projects a total dune and cliff erosion of 2.9 square miles (80.8 million square feet) with 1.4 meters (4.6 feet) of sea level rise by 2100. Projected rates of average and maximum dune and cliff retreat inform the severity of future erosion and impact on existing coastal development in close proximity to the shoreline (Table 5-35). These values project the total amount of erosion and average landward retreat of the county by 2100, and do not consider short-term responses of sandy beaches, dunes, and cliffs as a result of coastal storms (e.g., cliff failure due to severe wave attack). Dune and cliff erosion rates vary significantly 9412110 Port San Luis, California 0 .93 + /-0.38 mm /yr 0.60 ir-;::============;---------------:-:-----------------=, -Linear Relativ e Sea Le v el Trend 0.45 -U1111er 95% Confidence Interval --------------~----------~---~~--Lower 95% Confidence Interval 0.30 Monthly mean sea level with the -a.v era.ge seasonal cycle remo ved 0.15 .. L .., 0.00 ., ~ -0.15 -0.3 0 -0.45 -0.60 1900 1910 192 0 193 0 1940 195 0 1960 1970 1980 1990 2 000 2 010 2 0 2 0 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-116 throughout due to geological composition and the physical forces acting on the coastline; therefore, actual erosion and shoreline retreat distance will not be uniform throughout the county. Further, areas protected by hard structures such as seawalls (i.e. Avila Beach) will also experience lesser impacts of cliff erosion than unaltered natural coastlines. Actual future rates of erosion are relative to future coastal processes and difficult to project with certainty. Projected rates of erosion are naturally varied and will likely accelerate by 2100; thus, most erosion will occur towards the end of the century (Heberger et. al 2009). Table 5-35 Coastal Erosion Projections with 1.4 meter (4.6 foot) Sea Level Rise by 2100 San Luis Obispo Total Erosion Area1 Average Retreat Distance2 Maximum Retreat Distance Dune Erosion 1.4 square miles 150 meters / 492 feet 330 meters / 1083 feet Cliff Erosion 1.5 square miles 78 meters / 256 feet 280 meters / 918 feet 1 Total Erosion Area refers to the total area of dunes or cliff loss due to erosion projected to occur by 2100. 2 Retreat Distance refers to the landward retreat of dunes or cliffs as a result of coastal erosion projected to occur by 2100. Source: (Heberger et. al 2009). Sea Level Rise: Likely. Scientific understanding of sea level rise is advancing at a rapid pace; projections of future sea level rise continue to change as new studies become available. Future climate change is projected to particularly affect sea levels as the glaciers, polar ice packs, and ice sheets retreat. The predicted sea level rise over the course of this century varies widely. Since 1992, trends in sea level rise have been monitored by satellites and recorded by tide gauges. Given the variables involved, it is not yet possible to determine the actual rate of sea level increase. The Ocean Protection Council (OPC) suggests that sea level rise along the coast of California could occur on the order of 0.5-1.0 foot by 2030, 1.0-2.6 feet by 2050, and 3.1-10 feet by 2100 (Table 5-36). These sea level rise scenarios are based on various projections of global greenhouse gas (GHG) emissions. The probabilities take into account uncertainties related to each of these scenarios. In addition, Rising Seas in California: An Update on Sea-Level Rise Science identifies an extreme sea level rise scenario (H++) that projects 10 feet of sea level rise by 2100 based on an accelerated rate of Arctic and Antarctic ice sheet loss (Griggs et. al. 2017). The H++ scenario assumes a trajectory of high GHG emissions and an accelerated rate of Arctic and Antarctic ice sheet loss. Note that there is a high level of uncertainty associated with the H++ scenario (as well as all SLR projections and projected timing) and given the emerging nature of SLR science, these estimates are intended to be used as a guide only and are subject to refinement over time. If this extreme sea level rise scenario were to occur, the modeled elevations of sea level rise and associated hazards could be experienced substantially sooner than the projected horizon year. Table 5-36 Sea Level Rise Projections Projected Horizon Year / Time 67% Probability SLR meets or exceeds 0.5% Probability SLR meets or exceeds H++ Extreme SLR Scenario (no probability assigned) 2030 0.5 ft 0.7 ft 1.0 ft 2050 1.0 ft 1.8 ft 2.6 ft 2100 2.1-3.1 ft 5.4-6.7 ft 9.9.ft Note: Probabilities based on projections by the OPC for both low and high GHG emissions scenarios (Griggs et. al. 2017). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-117 Climate Change Considerations As ocean temperatures warm as a result of climate change, the water in the ocean expands and occupies more volume, resulting in a rise in sea levels. In addition, global sea levels rise from the additional volume of water added to the oceans from the melting of mountain glaciers and ice sheets on land. The rate at which sea levels will rise is largely dependent on the melting of the ice, which changes the land cover from a reflective ice surface to open ocean water; the ocean continues to absorb more of the sun’s energy and subsequently increases the rate of ice melt. The uncertainties associated with the rate at which ice melt occurs is largely responsible for the wide variation in sea level rise projections in the latter half of this century (i.e., between 2050 and 2100) and can explain the H++ scenario. The time scales for sea level rise are related to complex interactions between the atmosphere and the oceans, delays in stabilizing GHG levels in the atmosphere, and the dissolution of those gases into the ocean. The Intergovernmental Panel on Climate Change (IPCC) has published scientific evidence that demonstrates that sea levels will be rising for the next several thousand years due to the GHGs that have already been released into the atmosphere. Much of the scientific advancement in recent years has been in understanding the contribution and rate of ice melt to global sea levels. It has also revealed the potential for extreme sea level rise resulting from rapid acceleration of ice melt as noted above under the RCP 8.5 and H++ scenarios. In general, the higher the GHG emissions, the higher the temperature, the more rapid the ice melt, and the higher the rate of sea level rise. A study conducted to examine the variability of coastal storms in California using historical records of storms and tide gauge data in San Francisco identified an increasing trend in the frequency and intensity of coastal storms over the last 50 years (Bromierski et. al 2003). Increasing trends in climate-related variables have also been identified by studies of cyclone frequency (Graham & Diaz 2001) and wave height (Allan & Komar 2000); these have been substantially affected in the last two decades by increased coastal storm frequency and intensity. Continuation of these trends would have serious consequences for structures and ecosystems along the West Coast. The projected frequency and intensity of future coastal storms, however, is difficult to confidently quantify (Bromierski et. al 2003). Vulnerability The assessment of vulnerabilities to coastal storms, coastal erosion, and sea level rise within San Luis Obispo County relies on the best available science and modeling and methodology from a range of sources including FEMA and OPC planning guidance. Data was derived from several sources, including NOAA sea level rise viewer and previous studies that quantify historic rates of coastal erosion and frequency/severity of coastal storms and provide evidence for future trends (NOAA 2019b; USGS 2018). This assessment is further guided by FEMA’s Local Mitigation Planning Handbook (2013), which provides strategies to describe and quantify hazards risk in the context of individual jurisdictions. Sea level rise modeling and adaptation is an evolving field. The sea level rise projections used in studies previous to this Plan to identify vulnerabilities do not reflect the most recent update of California sea level rise guidance, as provided in the California OPC 2018 State of California Sea-Level Rise Guidance Update (OPC 2018). The NOAA Sea Level Rise and Coastal Flooding Impacts online tool uses a “bathtub” model comparing water elevations to ground elevation contours but may not fully account for hydrodynamics such as King Tides, storm surges or wave run-up, often key elements in coastal flooding. Spatial data layers within the CSMW WebMapper developed by the Pacific Institute (2009) also estimate areas that will be affected by future sea level rise; however, the data layers also use the “bathtub” model and do not ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-118 reflect the most recent sea level rise projections, which are substantially higher than those used within the Pacific Institute model. The CSMW WebMapper layers that identify areas vulnerable to bluff erosion and dune erosion hazards represent all dunes and bluffs as susceptible to sea level rise induced erosion with a 55-inch (4.6-foot) rise in sea level by 2100 (USACE 2016). The Pacific Institute spatial data layers provide projections for coastal bluff and cliff erosion in total area of erosion (square miles) and shoreline retreat (linear meters/feet) with sea level rise of 1.4 meters (4.6 feet) by 2100. Historic and projected rates of erosion inform future vulnerability of coastal development; however, erosion future rates are relative to variable coastal hazards and are difficult to quantify. A San Luis Obispo California Polytechnic State University graduate study titled A Sea Level Rise Vulnerability Assessment and Adaptation Strategies for the County of San Luis Obispo completed to inform future updates of the Safety Element of the County’s General Plan analyzed the potential impacts of coastal hazards and sea level rise to identify vulnerabilities along the coast (Protsman 2018). This study provides site-specific erosion rates and detailed maps of site-specific shoreline change and coastal hazards that utilizes USGS and Pacific Institute data (Protsman 2018; USGS 2018). USGS data provides information on coastal change hazards during storms, beach morphology during extreme storms, short- term and long-term shoreline change rates, a coastal vulnerability index, and probabilities of coastal shoreline retreat on a regional scale. USGS has a more localized and accurate model called the Coastal Storms Modeling System (CoSMoS), and this model had not yet been applied to San Luis Obispo County until mid-2019. As this modeling represents more current sea level rise science it was integrated into this HMP before it was finalized. This was also done to reflect the most recent update of California sea level rise guidance, as provided in the California OPC 2018 State of California Sea-Level Rise Guidance Update (OPC 2018). The California Coastal Commission (CCC) requires sea level rise analysis and bluff retreat studies for new coastal development permits, which provide site-specific research on historic and projected rates of sea level rise and bluff erosion. Individual jurisdictions, such as the city of Pismo Beach, have also conducted sea level rise and bluff erosion studies to evaluate vulnerability and establish policies for reviewing proposed coastal development. Sea level rise studies and adaptation reports conducted for smaller jurisdictions include site-specific coastal modeling including the Morro Bay Sea Level Rise Adaptation Strategy Report (Moffat & Nichol 2018). General Property Public and private property vulnerable to coastal storms, coastal erosion, and sea level rise generally include low-lying coastal structures and those built close to the edge of eroding bluffs. Vulnerable private development primarily includes residential and commercial buildings in cities and unincorporated communities, as well as agricultural buildings in rural areas. Parcels located in close proximity to the coastline include agriculture and residential structures, commercial structures, industrial structures, agriculture and residential parcels, commercial parcels, and industrial parcels. (County of San Luis Obispo 2018; Protsman 2018). A property risk assessment conducted by Protsman (2018) determined that the buildings and parcels with the highest vulnerability are located within the central and northern regions of the coast due to health, safety, and displacement concerns of damaged or destroyed structures and parcels (Protsman 2018). Coastal hazard impacts on coastal property are dependent on several factors including the elevation and composition of the shoreline (i.e. wide sandy beach versus a rocky intertidal beach fronting coastal bluffs). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-119 For example, structures built adjacent to eroding bluffs are vulnerable to bluff erosion and coastal storms. Public and private property susceptible coastal storms and projected sea level rise may be protected through shoreline adaptation measures including hard structures such as seawalls or rock revetments or softer approaches such as beach nourishment that slow the landward retreat of the shoreline (USACE 2016). Natural features such as dune fields and coastal cliffs exist over much of the county coastline that are subject to irreversible beach and bluff erosion. However, less than 5 percent of the San Luis Obispo County coastline is estimated to be protected from coastal hazards with hard structures such as revetments or seawalls as of 2016 (USACE 2016). Figure 5-40 Residential and Commercial Coastal Development in Morro Bay Low-lying commercial and residential coastal development in Morro Bay is has little protection from coastal flooding and sea level rise; however, the strand and dunes across the bay provide some protection from strong offshore swells. Photo Source: San Luis Obispo Tribune 2014. As an estimate of potential losses to coastal flooding a GIS analysis of exposure within FEMA coastal flood zones (VE) was completed. The GIS analysis takes into account improved values of properties and estimated content values. Approximately 64 properties worth $3 million is currently exposed, including both improved and content value within Morro Bay, Pismo Beach, and unincorporated areas based on the intersection of improved parcel centers with VE flood hazard areas (Table 5-37). Note that the type of properties with the greatest exposure include a number of government/utilities and exempt properties that do not have valuations in the assessor’s data, thus the property values are likely under-represented. The loss estimate assumes 50% of the structure and content exposure value due to the potential for deeper flooding and wave effects associated with the VE zones. The unincorporated areas, such as low- lying areas in Cayucos, are exposed to the highest total value and greatest loss estimate due to potential coastal flooding (Table 5-38). While this analysis generally shows relatively low risk to existing development, the risk could increase over time with sea level rise. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-120 Table 5-37 Coastal Flooding Hazard Exposure – General Property Summary by Jurisdiction Jurisdiction Property Count Improved Value Content Value Total Value Loss Estimate Population MORRO BAY 11 $5,724 $0 $5,724 $2,862 - PISMO BEACH 10 N/A N/A N/A N/A - Unincorporated 43 $2,016,245 $1,008,123 $3,024,368 $1,512,184 8 TOTAL 64 $2,021,969 $1,008,123 $3,030,092 $1,515,046 8 Source: Parcel analysis by Wood. Table 5-38 Coastal Flooding Hazard Exposure by Property Type Property Type Property Count Improved Value Content Value Total Value Loss Estimate Population Government/Utilities 48 -- -- N/A N/A -- Other/Exempt/Misc 10 -- -- N/A N/A -- Residential 1 $968,412 $484,206 $1,452,618 $726,309 3 Multi-Family Residential 1 $972,774 $486,387 $1,459,161 $729,581 3 Residential: Other 1 $75,059 $37,530 $112,589 $56,294 3 Vacant 3 $5,724 -- $5,724 $2,862 -- TOTAL 64 $2,021,969 $1,008,123 $3,030,092 $1,515,046 8 Source: Parcel analysis by Wood. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-121 Sea Level Rise Impact Analysis A geographic information systems (GIS) overlay analysis was performed to determine parcels and critical facilities that may be affected by sea level rise. The GIS analysis method is the same in nature as that used with other hazard layers, which are used in an intersection process to determine whether a critical facility, shown as a point, or a developed parcel polygon, which is then converted to a centroid point to be more easily represented, either falls in or outside of each hazard area. For this particular overlay analysis two sets of sea level rise inundation data were used, based upon currently available (August 2019) modeling representative of the best available science. The U.S. Geological Survey Coastal Storm Modeling System Version 3.1 (USGS CoSMoS 3.1) data provides detailed projections of tidal inundation and coastal flood hazards between Golden Gate Bridge in San Francisco Bay and Point Conception in Santa Barbara County. Projections show the modeled flood extents under both existing conditions, and ten (10) possible future sea level rise scenarios ranging from 25 cm to 500 cm. CoSMoS 3.1 is based on global climate models (GCMs) developed by the Intergovernmental Panel on Climate Change and considers region-specific factors such as oceanographic conditions, backshore types (beach, bluff or estuarine), long-term changes in the shoreline, river and stream drainages, wind patterns, and seasonal changes. The model identifies areas along the coast where significant flooding may occur under both a non-storm scenario and storm scenarios. With CoSMoS 3.1 data, for each modeled increase in sea level elevation, there is a minimum, average and maximum range of uncertainty that is modeled. The maximum uncertainty scenario was used for the purposes of this analysis, which effectively models a worst-case scenario for each given SLR scenario. The SLR analysis includes three ranges of sea level rise across two scenarios, one with 100-year flooding and one without. Sea level rise scenarios selected for analysis are based on projections for San Luis Obispo provided by the Ocean Protection Council State of California Sea -Level Rise Guidance (OPC 2018) under a worst case, or extreme risk aversion scenario (H++ scenario within Table 5-36 above). The H++ scenario was selected for analysis as the intent is to identify infrastructure and critical facilities that could be irreversibly damaged by sea level rise, or would be significantly costly to repair, and would have considerable impacts to public safety, health, or environmental resources. The first phase of analysis models property and critical facility exposure to an average maximum tidal inundation at these increments: •Area extent of maximum tidal inundation with 25cm (approximately 1.0 ft) increase in sea level rise •Area extent of maximum tidal inundation with 75cm (approximately 2.6 ft) increase in sea level rise •Area extent of maximum tidal inundation with 300cm (approximately 9.9 ft) increase in sea level rise These hazard zones show the projected maximum extent of what will be regularly flooded by tidal movements under the three sea level rise elevations. The second scenario of analysis uses the same sea level rise elevations previously described but models the area extent of inundation associated with a 100-year coastal flood event (or 1% annual chance coastal flood including waves). The addition of the flooding worsens the extent of the overall inundation and represents how coastal and estuarine flooding will be exacerbated by sea level rise in the future. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-122 • Area extent of flooding from 100-year coastal flood event with 25cm (approximately 1.0 ft) increase in sea level rise • Area extent of flooding from 100-year coastal flood event with 75cm (approximately 2.6 ft) increase in sea level rise • Area extent of flooding from 100-year coastal flood event with 300cm SLR (approximately 9.9 ft) increase in sea level rise An exposure analysis was performed to identify the counts of improved properties, values of those properties, and critical facilities located within the six scenarios. The number of parcels and critical facilities were aggregated by parcel type and community (whether incorporated or instead a Community Services District or Special District) or critical facility type and category. Improved value totals were calculated by summing up all the improved values of the parcels of each type and in each community, as summarized in the following tables. As a clarification, improved values are the values of the developments, or improvements, not land value. The analysis does not predict damage loss, as property and content values may change in the future, and it is assumed that some property will eventually be relocated or removed prior to permanent inundation. The analysis does not account for undeveloped parcels that might be permanently inundated by sea level rise in the future. Note that the inundation events become progressively more extensive with the addition of the deeper sea level rise levels, thus property that is inundated in the 25cm and 75cm scenarios is also inundated in the 300cm scenario and are totaled as such. The following results are aggregated into three main categories: incorporated jurisdictions, community service districts, and special districts. A total of six tables are provided, two for each category, that depict the count of exposed parcels and values of improvements on those parcels for the three sea level rise scenarios, both with and without the 100-year flood (Note: SLR stands for Sea Level Rise). Table 5-39 Number of Parcels Inundated by Sea Level Rise, with and without a 1% Annual Chance Coastal Flood – Incorporated Jurisdictions Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Grover Beach Commercial -- -- 6 -- -- 6 Government/Utilities -- -- 4 -- -- 7 Other/Exempt/Misc. -- -- 4 -- -- 9 Residential -- -- 2 -- -- 15 Multi-Family Residential -- -- 3 -- -- 9 Mobile/Manufactured Homes -- -- -- -- -- 1 Industrial -- -- 1 -- -- 3 TOTAL 0 0 20 0 0 50 Morro Bay Commercial -- - 12 - - 50 Government/Utilities 1 1 19 -- 1 12 Other/Exempt/Misc. -- -- 6 1 3 19 Residential -- 1 12 -- -- 9 Residential: Other -- - 3 1 1 76 Vacant 1 1 3 -- 1 4 TOTAL 2 3 55 3 7 124 Pismo Beach Commercial -- -- 9 2 4 9 Government/Utilities 1 1 12 4 5 13 Other/Exempt/Misc. -- 1 18 1 6 22 Residential 1 2 37 2 9 41 Multi-Family Residential -- -- 93 -- 6 104 Mobile/Manufactured Homes -- -- 3 -- 2 3 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-123 Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Residential: Other -- -- 7 -- -- 13 TOTAL 2 4 179 9 32 205 Unincorporated Agricultural -- -- 4 3 3 4 Commercial -- 2 46 4 15 59 Government/Utilities 1 2 35 8 16 48 Other/Exempt/Misc. -- -- 43 2 16 59 Residential -- 14 434 30 92 563 Multi-Family Residential -- 1 110 3 18 163 Mobile/Manufactured Homes -- -- 2 -- -- 2 Residential: Other 1 1 39 3 14 47 Vacant -- -- 21 1 13 25 TOTAL 2 20 734 54 187 970 Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS, ParcelQuest 2018, Wood Parcel Analysis. Table 5-40 Improved Values of Properties Inundated by Sea Level Rise with and without a 1% Annual Chance Coastal Flood – Incorporated Jurisdictions Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Grover Beach Commercial -- -- $834,388 -- -- $834,388 Government/Utilities* -- -- -- -- -- -- Other/Exempt/Misc.* -- -- $3,181,722 -- -- $3,883,627 Residential -- -- $198,637 -- -- $1,675,517 Multi-Family Residential -- -- $971,575 -- -- $3,466,989 Mobile/Manufactured Homes -- -- -- -- -- $305,343 Industrial -- -- $62,392 -- -- $107,956 TOTAL $0 $0 $5,248,714 $0 $0 $10,273,820 Morro Bay Commercial -- -- $4,441,799 -- $800,000 $4,441,799 Government/Utilities* -- -- -- -- -- -- Other/Exempt/Misc.* -- -- $74,906 -- -- $74,906 Residential -- $42,463 $3,930,417 $42,463 $42,463 $30,817,911 Residential: Other -- -- $7,707,961 -- $4,072,244 $9,981,210 Vacant $5,724 $5,724 $3,312,145 $5,724 $5,724 $3,337,145 TOTAL $5,724 $48,187 $19,467,228 $48,187 $4,920,431 $48,652,971 Pismo Beach Commercial -- -- $3,931,762 $255,000 $330,726 $3,931,762 Government/Utilities* -- -- -- -- -- Other/Exempt/Misc.* -- $2,214,828 $3,727,316 $2,214,828 $2,349,497 $3,727,316 Residential $174,047 $176,839 $6,468,297 $176,839 $3,056,157 $6,933,545 Multi-Family Residential -- -- $22,908,703 -- $1,255,367 $24,617,998 Mobile/Manufactured Homes -- -- $17,059,909 -- $16,215,406 $17,059,909 Residential: Other -- -- $13,124,415 -- -- $17,033,080 TOTAL $174,047 $2,391,667 $67,220,402 $2,646,667 $23,207,153 $73,303,610 Unincorporated Agricultural -- -- $286,564 $120,863 $120,863 $286,564 Commercial -- $546,320 $11,955,715 $981,159 $3,759,287 $16,209,339 Government/Utilities* -- $8,491,063 $26,751,762 $8,491,063 $8,552,857 $26,921,391 Other/Exempt/Misc.* -- -- $13,477,246 $645,000 $5,987,495 $19,278,257 Residential -- $2,323,098 $83,336,297 $4,859,099 $21,089,501 $110,892,058 Multi-Family Residential -- $125,465 $15,885,589 $693,107 $5,211,282 $30,108,820 Mobile/Manufactured Homes -- -- $343,452 -- -- $343,452 Residential: Other $75,059 $75,059 $16,669,622 $2,084,548 $10,138,380 $34,731,855 Vacant -- -- $3,616,752 $10,404 $2,958,652 $6,135,235 TOTAL $75,059 $11,561,005 $172,322,999 $17,885,243 $57,818,317 $244,906,971 *Values may be underestimated as some values not available in parcel data due to being exempt from tax assessment. Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS, ParcelQuest 2018, Wood Parcel Analysis. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-124 Table 5-41 Number of Parcels Inundated by Sea Level Rise with and without a 1% Annual Chance Coastal Flood – Community Service Districts Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Avila Beach Commercial -- -- 10 -- 8 12 Government/Utilities -- -- 7 1 6 7 Other/Exempt/Misc. -- -- 13 -- 12 14 Residential -- -- 14 -- 9 15 Multi-Family Residential -- -- 19 -- 15 28 Residential: Other -- -- 10 -- 10 11 Vacant -- -- 13 -- 11 16 TOTAL 0 0 86 1 71 103 Los Osos Commercial -- 2 12 3 5 15 Government/Utilities -- -- 1 -- 1 1 Other/Exempt/Misc. -- -- 1 1 1 1 Residential -- 14 222 28 71 294 Multi-Family Residential -- - 4 -- - 10 Mobile/Manufactured Homes -- - 1 -- - 1 Residential: Other 1 1 3 3 3 3 Vacant -- - 2 1 2 2 TOTAL 1 17 246 36 83 327 Oceano Agricultural -- - 1 -- - 1 Commercial -- - 9 -- - 13 Government/Utilities -- -- 10 -- -- 10 Other/Exempt/Misc. -- - 17 -- - 20 Residential -- - 145 -- - 162 Multi-Family Residential -- - 71 -- - 76 Mobile/Manufactured Homes -- - 1 -- - 1 Residential: Other -- - 20 -- - 24 Vacant -- - 2 -- - 2 TOTAL 0 0 276 0 0 309 San Simeon Government/Utilities -- - - 1 1 1 Multi-Family Residential -- - - -- - 21 Other/Exempt/Misc. -- - - -- - 3 TOTAL 0 0 0 1 1 25 Cambria Government/Utilities -- -- -- -- -- 4 Other/Exempt/Misc. 1 1 1 1 1 1 Residential -- -- 7 -- -- 30 TOTAL 1 1 8 1 1 35 Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS, ParcelQuest 2018, Wood Parcel Analysis. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-125 Table 5-42 Value of Improved Values of Properties Inundated by Sea Level Rise and 1% Annual Chance Coastal Flood – Community Service Districts Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Avila Beach Commercial -- -- $4,744,109 -- $2,427,671 $6,267,359 Government/Utilities* -- -- $61,794 -- $61,794 $61,794 Other/Exempt/Misc.* -- -- $5,342,495 -- $5,342,495 $7,605,508 Residential -- -- $5,286,138 -- $4,001,139 $5,394,363 Multi-Family Residential -- -- $5,157,029 -- $4,518,175 $8,464,474 Residential: Other -- -- $7,193,724 -- $7,193,724 $22,050,689 Vacant -- -- $3,248,427 -- $2,937,427 $5,744,835 TOTAL $0 $0 $31,033,716 $0 $26,482,425 $55,589,022 Los Osos Commercial -- $546,320 $2,243,469 $744,960 $883,510 $2,544,092 Government/Utilities* -- -- -- -- -- -- Other/Exempt/Misc.* -- -- $420,000 $420,000 $420,000 $420,000 Residential -- $2,323,098 $41,957,596 $4,462,878 $12,338,675 $55,511,993 Multi-Family Residential -- -- $1,264,339 -- -- $3,120,843 Mobile/Manufactured Homes -- -- $62,149 -- -- $62,149 Residential: Other $75,059 $75,059 $2,084,548 $2,084,548 $2,084,548 $2,084,548 Vacant -- -- $21,225 $10,404 $21,225 $21,225 TOTAL $75,059 $2,944,477 $48,053,326 $7,722,790 $15,747,958 $63,764,850 Oceano Agricultural -- -- $165,701 -- -- $165,701 Commercial -- -- $1,558,192 -- -- $2,094,953 Government/Utilities* -- -- $0 -- -- $0 Other/Exempt/Misc.* -- -- $2,891,663 -- -- $3,045,326 Residential -- -- $23,372,714 -- -- $26,784,979 Multi-Family Residential -- -- $6,749,991 -- -- $8,992,923 Mobile/Manufactured Homes -- -- $281,303 -- -- $281,303 Residential: Other -- -- $2,792,785 -- -- $4,238,793 Vacant -- -- $242,315 -- -- $242,315 TOTAL $0 $0 $38,054,664 $0 $0 $45,846,293 San Simeon Government/Utilities -- -- -- -- -- $0 Multi-Family Residential -- -- -- -- -- $4,274,750 Other/Exempt/Misc. -- -- -- -- -- $0 TOTAL $0 $0 $0 $0 $0 $4,274,750 Cambria Government/Utilities* -- -- -- Other/Exempt/Misc.* -- -- -- -- -- -- Residential -- -- $2,255,769 -- -- $10,685,000 TOTAL $0 $0 $2,255,769 $0 $0 $10,685,000 *Values may be underestimated as some values not available in parcel data due to being exempt from tax assessment. Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS 2018, ParcelQuest, Wood Parcel Analysis. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-126 Table 5-43 Number of Parcels Inundated by Sea Level Rise with and without 1% Annual Chance Coastal Flood – Special Districts Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Cayucos Sanitation District Commercial -- - 15 1 2 19 Government/Utilities -- -- 11 4 6 14 Other/Exempt/Misc. -- - 10 1 3 12 Residential -- - 46 2 12 83 Multi-Family Residential -- 1 16 3 3 28 Residential: Other -- - 6 -- 1 8 Vacant -- - 3 -- - 3 TOTAL 0 1 107 11 27 167 Port San Luis Harbor District Government/Utilities 1 2 5 2 4 5 Other/Exempt/Misc. -- -- 1 -- -- 1 TOTAL 1 2 6 2 4 6 South San Luis Obispo County Sanitation** Agricultural -- -- 1 -- - 1 Commercial -- -- 15 -- - 19 Government/Utilities -- -- 13 -- - 16 Other/Exempt/Misc. -- -- 21 -- - 29 Residential -- -- 147 -- - 177 Multi-Family Residential -- -- 74 -- - 85 Mobile/Manufactured Homes -- -- 1 -- - 2 Residential: Other -- -- 20 -- - 24 Industrial -- -- 1 -- - 3 Vacant -- -- 2 -- - 2 TOTAL 0 0 295 0 0 358 Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS, ParcelQuest 2018, Wood Parcel Analysis. Table 5-44 Improved Values of Properties Inundated by Sea Level Rise with and without a 1% Annual Chance Coastal Flood – Special Districts Location Parcel Type 25-cm SLR 75-cm SLR 300-cm SLR 25-cm SLR w/ 1% Flood 75-cm SLR w/ 1% Flood 300-cm SLR w/ 1% Flood Cayucos Sanitation District Commercial -- -- $3,409,945 $236,199 $448,106 $5,302,935 Government/Utilities* -- -- $0 -- -- $169,629 Other/Exempt/Misc.* -- -- $4,823,088 $225,000 $225,000 $6,418,638 Residential -- -- $11,574,166 $396,221 $4,749,687 $21,631,681 Multi-Family Residential -- $125,465 $2,714,230 $693,107 $693,107 $5,255,830 Residential: Other -- -- $4,598,565 -- $860,108 $5,444,156 Vacant -- -- $104,355 -- -- $104,355 TOTAL $0 $125,465 $27,224,349 $1,550,527 $6,976,008 $44,327,224 Port San Luis Harbor District Government/Utilities* -- $8,491,063 $26,689,968 $8,491,063 $8,491,063 $26,689,968 Other/Exempt/Misc.* -- -- -- -- -- -- TOTAL $0 $8,491,063 $26,689,968 $8,491,063 $8,491,063 $26,689,968 South San Luis Obispo County Sanitation** Agricultural -- -- $165,701 -- -- $165,701 Commercial -- -- $2,392,580 -- -- $2,929,341 Government/Utilities* -- -- $0 -- -- $0 Other/Exempt/Misc.* -- -- $6,073,385 -- -- $6,928,953 Residential -- -- $23,571,351 -- -- $28,460,496 Multi-Family Residential -- -- $7,721,566 -- -- $12,459,912 Mobile/Manufactured Homes -- -- $281,303 -- -- $586,646 Residential: Other -- -- $2,792,785 -- -- $4,238,793 Industrial -- -- $62,392 -- -- $107,956 Vacant -- -- $242,315 -- -- $242,315 TOTAL $0 $0 $43,303,378 $0 $0 $56,120,113 *Values may be underestimated as some values not available in parcel data due to being exempt from tax assessment. **Note that South SLO Sanitation District encompasses the Cities of Grover Beach and Arroyo Grande as well as the majority of the Oceano CSD. As such, the totals for the Sanitation District may be duplicative when compared to the other cities' and the CSD's totals. Source: USGS CoSMoS v3.1 (2019), San Luis Obispo Assessor’s Office/GIS, ParcelQuest 2018, Wood Parcel Analysis. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-127 The results of the parcel analysis are projected estimates based on available data and modeling results, which are subject to change based on the actual rate of sea level rise and the frequency and duration of coastal storms. Sea level rise alone is not anticipated to be the primary cause of damage, but rather, sea level rise exacerbates existing coastal hazards, including damage caused by severe storms and the frequency, duration, and extent of tidal flooding. Further, this analysis assumes no adaptation nor mitigation strategies are in place; implementation of future mitigation strategies may minimize these impacts. The parcel analysis indicates the greatest vulnerability from sea level rise is within the unincorporated areas of the County and incorporated areas of Pismo Beach and Morro Bay. The results do not show any property at risk within Grover Beach, which is largely set-back further and has less coastal development. Both Morro Bay and Pismo Beach have relatively low vulnerability to the 25cm and 75cm tidal inundation scenarios, but vulnerability increases significantly with a 300cm scenario. Combined with a 300cm and 100-year coastal flood scenario, the property at risk nearly doubles for Morro Bay. The unincorporated areas of the County have the most overall vulnerability in terms of counts and values of improved parcels. The majority of these vulnerable areas are located in the community service districts of Los Osos, Oceano, Avila Beach, Cayucos and Cambria. Regarding the community service districts (CSD), Los Osos, Oceano, and Avila Beach have the greatest number of improved parcels potentially vulnerable to sea level rise. All three communities have significant counts of developed parcels in the 300cm inundation level, both with and without the 100-year flood. In terms of improved parcel impacts the Port San Luis Harbor District, South San Luis Obispo County Sanitation District and Cayucos Sanitation District is more vulnerable to the 300cm inundation level, with relatively minor impacts to the smaller levels of inundation. Note that the South San Luis Obispo County Sanitation District has overlap with Oceano and the Grover Beach. The values of property at risk for the Port San Luis Harbor District include two piers, with values provided by the District. There is potential for other property and infrastructure in the District to be at risk that is not accounted for due to limitations in the asset database. People Some populations are more vulnerable to coastal erosion, coastal flooding, and sea level rise impacts due to having certain sensitivities, an increased likelihood of exposure, or a lower adaptive capacity (Public Health Institute Center for Climate Change and Health 2016). Demographic characteristics including health conditions that affect physical ability and health, or socioeconomic factors that amplify risk factors for poor health conditions, may affect the abilities of individuals or households to prepare for, respond to, and recover from coastal hazards (EPA 2017). Specific attributes may create additional stresses on individuals and communities resulting in reduced resiliency in the event of a coastal hazard event. Many of these factors may also be exacerbated by the specific, localized nature of flooding, erosion, and other impacts associated with sea level rise. Social Vulnerability Coastal areas with a high social vulnerability index inform which communities are more susceptible to adverse impacts of coastal storms, flooding, and sea level rise. Based on the SoVI data presented and ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-128 discussed in subsection 4.4.1, populations along the coastline that are most socially vulnerable to coastal hazards are identified as Grover Beach, Oceano, and San Simeon. A San Luis Obispo California Polytechnic State University graduate study titled A Geospatial Assessment of Social Vulnerability to Sea-Level Rise in Coastal San Luis Obispo County was also referenced as another source for a preliminary assessment of social vulnerability exposure (Carpentier 2017). This study focused on the unincorporated areas only, and suggests higher social vulnerability in San Simeon, Cambria, and Avila Beach. Based on 2000 U.S. Census Bureau data and coastal floodplain modeling, the estimated population of the county vulnerable to a 1-percent-annual-chance extreme coastal flood event is approximately 670 people (Heberger et. al 2009). A 1.4-meter (4.6-foot) increase in sea level rise is projected to increase the number of people in the county vulnerable to a 100-year coastal flood event to approximately 1,300, resulting in a 98% increase in the affected population. Of these, 85% identify as white, including white Hispanics, and 13% identify as a minority race. Additionally, approximately 45% of this vulnerable group is considered low-income (<$30,000/year) (CEC 2012). An additional 1,100 people are vulnerable to erosion-related risk along the coast as a result of 1.4 meter (4.6-foot) sea level rise. Critical Facilities and Infrastructure Critical facilities that are vulnerable to coastal hazards and sea level rise may include public transportation, wastewater treatment and water supply infrastructure, schools, law enforcement facilities, and community centers. Essential education facilities such as the Morro Bay High School and Coast Union High School may be subject to coastal storms and flooding exacerbated by future sea level rise. Coastal erosion also threatens the structural foundation of schools built close to the shoreline such as Shell Beach Elementary School. Law Enforcement Facilities that are in close proximity to the shoreline such as in Pismo Beach and Oceano are also vulnerable to coastal storms and flooding. Additional vulnerable facilities include the Cambria wastewater treatment plant and municipal wells in Santa Rosa and San Simeon Creeks, the Children’s Center and the Avila Beach Community Center, each of which is located within a low-lying area subject to potential inundation during a coastal storm. Regional and local-serving public and utility infrastructure vulnerable to coastal hazards and sea level rise include roads, bridges, railroad lines and crossings, wastewater treatment plants, culverts, water lines, communication line and towers, stormwater outlets, bike lanes, bike facilities, airports, and fiber optic lines. Utility infrastructure containing hazardous materials that are vulnerable to coastal hazards and sea level rise include hazardous material facilities, the Diablo Canyon Nuclear Power Plant, underground tanks, and Regional Water Quality Control Board clean-up sites (Protsman 2018). Facilities that are impacted by coastal hazards could also result in a release of hazardous materials or deteriorating water or air quality, as well as disruption to key public and utility services to the wider community. Such vulnerable facilities include: • The Diablo Canyon Power Plant • San Simeon Wastewater Treatment Plant • Cayucos Sanitary District • Cambria Community Services District Municipal Water Wells • Cambria Community Services District Wastewater Treatment Plant • Oceano Wastewater Treatment Plant ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-129 • City of Morro Bay Wastewater Treatment Plant • Oceano County Airport Low-lying transportation infrastructure is vulnerable to the impacts of coastal hazards, including roads in Cayucos, Avila Beach, portions of the Southern Pacific Railroad, and sections of Highway 1 and Highway 101 (Caltrans 2018a). Highway 1 was found to be potentially vulnerable to inundation, flooding, and bluff erosion hazards as a result of sea level rise (Figure 5-41), as existing shore protection is either absent or easily overwhelmed by overtopping waves (Moffat & Nichol 2018). Approximately 2.8 miles of Highway 1 at Piedras Blancas north of San Simeon was recently relocated inland due to past and future threatened damage from coastal bluff erosion. Figure 5-41 Low-lying Portions of Highway 1 in San Luis Obispo County Currently, low-lying sections of Highway 1 in San Luis Obispo County are vulnerable to coastal hazards such as erosion and inundation from coastal storms and sea level rise; a segment. Source: (Caltrans 2018b) Wastewater treatment plants for coastal communities located in low-lying areas along coastal streams may be vulnerable to coastal hazards and projected sea level rise. For example, while the Cambria Community Services District and Oceano wastewater treatment plants are both located more than 1,500 feet from the shoreline, their location in low-lying coastal stream valleys may make them vulnerable to the combination of fluvial flooding and tidal inundation associated with projected sea level rise. In addition, coastal community municipal wells, such as CCSD wells along San Simeon and Santa Rosa Creeks are located near the coast and may be vulnerable to sea level rise-related inundation or possible future salt water intrusion. Hazardous materials facilities such as underground gas tanks and known hazardous cleanup sites equate to higher potential losses because damage to such structures may implicate leaked chemicals that pose impacts to health and safety (Protsman 2018). Sea Level Rise Analysis on Critical Facilities Exposure of 11 critical facilities to sea level rise is noted in the following tables; all of these with the exception of one are not at risk until the 300cm level of inundation. Wastewater treatment plants potentially at risk include the Morro Bay/Cayucos WWTP, San Simeon WWTP, and South San Luis Obispo County WWTP; San Simeon’s WWTP is most vulnerable and at risk to 100-year coastal flooding with the 25cm SLR scenario. Table 5-45 summarizes the critical facilities based on sea level rise inundation type ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-130 and location, while Table 5-46 includes additional details on these facilities (facility name, address, type of facility, and category of the facility). Table 5-45 Critical Facilities in Sea Level Rise Areas by Facility Category and Location Facility Location Facility Category Total Facilities – SLR of 25cm Total Facilities – SLR of 75cm Total Facilities – SLR of 300cm Total Facilities – SLR of 25cm + 100-year flood Total Facilities – SLR of 75cm + 100-year flood Total Facilities – SLR of 300cm + 100-year flood Morro Bay Emergency Services -- -- 1 -- -- 1 High Potential Loss Facilities -- -- 1 -- -- 1 Lifeline Utility Systems -- -- 5 -- -- 5 TOTAL 0 0 7 0 0 7 San Simeon Lifeline Utility Systems -- -- -- 1 1 1 TOTAL 0 0 0 1 1 1 Cayucos -- -- -- 1 -- -- 1 TOTAL 0 0 1 0 0 1 South San Luis Obispo Sanitation District and Oceano Lifeline Utility Systems -- -- 1 -- -- 1 Oceano Transportation Systems -- -- 1 -- -- 1 TOTAL 0 0 2 0 0 2 GRAND TOTAL 0 0 10 1 1 11 Source: USGS CoSMoS v3.1, San Luis Obispo Planning & Building/GIS, HIFLD, SLO County Community Service Districts and Special Districts, Wood Parcel Analysis. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-131 Table 5-46 Critical Facilities in Sea Level Rise Areas by Facility Category and Location Facility Location Facility Name Facility Address Facility Category Facility Type Morro Bay Morro Bay/Cayucos Wastewater Treatment Plant 160 Atascadero Road Lifeline Utility Systems Wastewater Treatment Plant Microwave Service Tower Morro Bay Power Plant Lifeline Utility Systems Microwave Service Towers Microwave Service Tower Not Available Lifeline Utility Systems Microwave Service Towers Microwave Service Tower Not Available Lifeline Utility Systems Microwave Service Towers Morro Bay Electrical Substations PG&E Lifeline Utility Systems Energy Commission Substations Morro Bay Power Plant Dynegy, Inc. High Potential Loss Facilities Power Plants Morro Bay High School 235 Atascadero Rd Emergency Services Public Schools Cayucos Cayucos Fire Protection District 201 Cayucos Drive Emergency Services Fire Stations San Simeon San Simeon Wastewater Treatment Plant 9245 Balboa Ave Lifeline Utility Systems Wastewater Treatment Plant South San Luis Obispo Sanitation District and Oceano South San Luis Obispo Sd Wastewater Treatment Plant 1600 Aloha Pl Lifeline Utility Systems Wastewater Treatment Plant Oceano Oceano County Airport Oceano Transportation Systems Airport Source: USGS CoSMoS v3.1, San Luis Obispo Planning & Building/GIS, HIFLD, SLO County Community Service Districts and Special Districts, Wood Parcel Analysis. Economy The major economic industries in San Luis Obispo County by employment include tourism, retail, service industries, government, and agriculture (Moser, Ekstrom 2012). Developed areas of the San Luis Obispo coast that are important to tourism include Cambria/Moonstone Beach, Cayucos, Morro Bay, Port San Luis/Avila Beach, and Pismo Beach (USACE 2016). Although the most popular beaches are located in the southern part of the county, beach tourism is important throughout the county (USACE 2016). However, projected climate change and sea level rise could cause an overall reduction of economic value in beach visitation. Some beaches may potentially lose attendance and associated earnings due to loss of beach resulting from beach erosion, while others may experience increased attendance and beach-related earnings as beaches elsewhere become less usable for recreation (Moser and Ekstrom 2012). Vertical and lateral beach access points may also be affected by coastal erosion and inundation due to sea level rise, which would prevent residents and visitors from accessing the beach and may increase the risk of injuries (Protsman 2018). Beach tourism is important to the county’ economy and generates significant revenue as many visitors rent hotels or other accommodations, dine out or shop at area stores. Visitor-serving areas such as those in Oceano, Cambria, and Avila Beach include local businesses and hotels that benefit the local economy (Protsman 2018). These businesses depend on tourism, and cities and communities within San Luis Obispo benefit from sales tax revenues. Disruption of these areas due to impacts of coastal hazards and projected sea level rise could decrease economic activity and affect the local economy. Future coastal beach and bluff erosion in the county may also negatively impact coastal businesses and households and decrease coastal real estate opportunities. Coastal bluff failure due to coastal erosion can create hazardous conditions due to roadway collapse, undermined home foundations and damage to ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-132 utilities (Russell & Griggs 2012). Natural resources with recreational and economic value may also be adversely affected. The county supports some of the largest dune habitats in the State including Morro Bay State Park, Oceano Dunes Natural Preserve, and the Guadalupe-Nipomo Dunes, which are vulnerable to damages from coastal storms and erosion. As this vulnerability increases over time, damages may impact the economy of the area and impact viable coastal land uses. Coastal storms can also cause erosion impacts and severe flooding and inundation of economically important infrastructure such as harbors and buildings related to commercial and recreational fisheries (Moser and Ekstrom 2012). Historic, Cultural, and Natural Resources Historic resources along the coast include designated historic sites and points, county-designated Sensitive Resource Areas and Archeological Resource Areas, county and State Parks, and other important habitat resource areas (Protsman 2018). Historic resources close to the coastline include museums such as the Morro Bay Maritime Museum, Museum of Natural History, and the Oceano Depot Museum. Historic resources also include coastal features such as recreational piers in Cayucos, Pismo, Avila and the Point San Luis Lighthouse, and the restored historic warehouse at the foot of Harford Pier in Port San Luis Harbor (Port San Luis Harbor District 2007). Cayucos Pier is considered a historic property in the VE coastal 100-year flood zone. One of the most visually prominent historic natural landmarks immediately vulnerable to coastal hazards and sea level rise is Morro Rock. Morro Rock stands approximately 576 feet tall and was created from a volcanic plug. The area is a significant cultural and religious monument, as it was once the site of Chumash sacred rituals (City of Morro Bay 2018). Morro Rock is a protected State Historic Landmark (#821) that also provides nesting habitat for peregrine falcons, a previously endangered and currently fully protected species (Department of Fish and Wildlife 2019). Figure 5-42 Morro Bay and Morro Rock Morro Rock is a historical, cultural, and natural landmark at the mouth of Morro Bay that also provides nesting habitat for Peregrine Falcons. Photo Source: Morrobay.org 2019 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-133 The county’s coastline includes a variety of natural habitats including sandy beaches, subtidal soft-bottom, rocky tide pools, offshore reefs, bays, estuaries, and harbors (USACE 2016). These include several managed areas and protected habitats, including the State Marine Conservation Areas (SMCA), State Marine Reserves (SMR), State Marine Recreational Management Area (SMRMA), state parks and beaches, and state game refuges. These areas support ecologically significant habitats where endangered or threatened species occur, including designated critical habitat and nesting and foraging sites for shorebirds. State parks and beaches within the San Luis Obispo County coastline include Cayucos State Beach, Estero Bluffs State Park, Los Osos Oaks State Reserve, Montaña de Oro State Park, Morro Bay State Park, Morro Strand State Beach, Harmony Headlands State Park, Hearst San Simeon State Park, and the W.R. Hearst Memorial State Beach (Department of Parks and Recreation 2019). Figure 5-43 Estero Bluffs State Park, Cayucos The Estero Bluffs State Park has a variety of natural resources including intertidal areas, native grasslands, wetlands, low bluffs, and coastal terraces with hiking trails and 3 miles of beach, which is vulnerable to coastal hazards (Department of Parks and Recreation 2019). The combined influence of sea level rise and coastal hazards may result in a migration of habitat inland and to higher elevations, or a transition to a different habitat type. With this consideration, there may be development or other impediments to inland migration that may result in the net loss of habitat. For example, accelerated erosion of the Oceano Dunes may cause this habitat may migrate inland. If a freshwater wetland is exposed to rising tides, it will transition to a saline estuarine wetland. The faster the climate changes, the more difficult it will be for animal species to migrate and for floral habitats to re- establish elsewhere. Nevertheless, some of the more resilient species may adapt in place. Future Development Land use and development along the county’s shoreline is governed by the California Coastal Act. Regulations under the Coastal Act are typically administered by the county and local cities through adopted Local Coastal Plans, overseen by the California Coastal Commission (California Coastal Commission 2019; County of San Luis Obispo 2018). The California Coastal Commission mandates that a site-specific sea level rise analysis and bluff retreat study are performed to obtain a coastal development ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-134 permit for new development. Planning for proposed bluff-top development must assess the average long-term beach and bluff retreat rate, erosion rate due to various sea level rise scenarios, and erosion potential from 100-year storms and other extreme events. Bluff retreat studies must establish a “development setback” that creates a buffer behind which development would be protected from bluff erosion for a minimum of 75 years. The county and each incorporated city’s certified Local Coastal Plans govern land use planning and development permitting. The county’s General Plan, including the Framework for Planning- Coastal Zone guides development in unincorporated areas. The Estero Area Plan, North Coast Area Plan, San Luis Bay Coastal Area Plan, Port San Luis Harbor District Port Master Plan, and the South County Coastal Area Plan provide area specific guidance (County of San Luis Obispo 2019c). Each city also as a certified Local Coastal Plan which governs land use and permitting with the coastal areas of the cities. Risk Summary Coastal storms are a recurring hazard for San Luis Obispo County that impact the entire coastline. Wave run-up erodes the coastline at varying rates depending upon geological composition. Development located in proximity to the shoreline is most vulnerable to coastal hazards and sea level rise; however, impacts are variable. Residential development is most susceptible to damage from coastal bluff erosion due to cliff collapse and shoreline retreat. Low-lying development and infrastructure fronted by sandy beaches however, are most vulnerable to dune erosion and impacts of sea level rise. Coastal Storms: • Coastal storms impact the entire coastline, causing beach and bluff erosion and coastal flooding of low-lying areas. • Proximity of structures to the coastline increases vulnerability to the effects of coastal storms, coastal erosion, and sea level rise. Coastal Erosion: • The County of San Luis Obispo coastline’s geologic composition and exposure to wave energy is quite varied. Sections of the coast range from rocky coastline to sandy beaches backed by cliffs, to sandy beaches backed by sand dunes. These differing characteristics affect erosion characteristics as well. • Short-term coastal erosion (e.g., cliff failure) occurs episodically, mainly during periods of intense wave action that coincides with high tides and coastal storms. • Annual rates of coastal erosion range from about three inches a year to more than one foot a year depending on coastline composition and exposure to coastal hazards. • Some of the potentially most vulnerable structures in the county are bluff top homes and business that are exposed to bluff erosion in the communities of San Simeon, Cayucos, Cambria and Pismo Beach. Public streets that border the coastal bluffs can also be subject of erosion damage. • Portions of communities are low-lying which can expose public facilities such as wastewater treatments plans to costal flood hazards. • Both bluff erosion and coastal flooding are exacerbated during major El Niño events such as the 2015-2016 El Niño event. • Coastal storm flooding hazards are limited throughout much of the county, while those from bluff erosion range from moderate to significant for bluff top homes and facilities. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-135 Sea Level Rise: • Future projected sea level rise may affect potential hazards in the county and is projected based on the best available science and modeling. • Rising sea levels alone are not anticipated to be the primary cause of vulnerabilities and potential damages to resources, property and infrastructure within San Luis Obispo County. • Impacts may instead be caused by existing severe storm coastal process-related hazards increasing in frequency and duration as a result of sea level rise. • If sea levels continue to rise at higher projected rates, episodic coastal erosion and coastal flooding impacts that already occur during large storm wave events could become more frequent, as predictable high tides may regularly inundate public beaches and low-lying coastal infrastructure. • Effects on people and housing: Historically, there has been little or no loss of life or injury in San Luis Obispo County due to coastal storms. The primary impacts have been economic in nature. • Effects on commercial and industrial structures: As beaches erode, the amount of recreational beach available to the public is substantially reduced. Changes in beach geometry can alter the wave characteristics of a particular site. Beach erosion results in the loss of sand from coastal areas. This hazard can accelerate the rate of erosion of coastal bluffs and can also contribute to increased wave- related damage to coastal structures. • Effects on infrastructure: Erosion of beach sand removes the natural barrier that protects landforms and structures from the potentially destructive wave action. The end result can be the direct destruction of roads, homes, and other structures by waves whose force is no longer dissipated by wide beaches. • Related Hazards: Adverse Weather, Flooding Table 5-47 Coastal Storm/Coastal Erosion/Sea Level Rise Hazard Risk Summary Jurisdiction Geographic Extent Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Limited Likely Limited Medium City of Arroyo Grande N/A N/A N/A N/A City of Atascadero N/A N/A N/A N/A City of Grover Beach Limited Occasional Limited Low City of Morro Bay Extensive Likely Critical High City of Paso Robles N/A N/A N/A N/A City of Pismo Beach Significant Occasional Limited Medium City of San Luis Obispo N/A N/A N/A N/A Avila Beach CSD Significant Likely Limited Medium Ground Squirrel Hollow CSD N/A Heritage Ranch CSD N/A Los Osos CSD Significant Likely Limited Low Nipomo CSD N/A San Miguel CSD N/A San Simeon CSD Significant Likely Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-136 Jurisdiction Geographic Extent Probability of Future Occurrence Magnitude/ Severity Overall Significance Templeton CSD N/A Cayucos Sanitary District Significant Likely Limited Medium Port San Luis Harbor District Significant Highly Likely Limited High San Luis Obispo FCWCD Limited Likely Limited Medium South San Luis Obispo Sanitation District N/A ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-137 5.3.8 Dam Incidents Hazard/Problem Description Dams are manmade structures built for a variety of uses, including flood protection, power generation, agriculture, water supply, and recreation. When dams are constructed for flood protection, they usually are engineered to withstand a flood with a computed risk of occurrence. For example, a dam may be designed to contain a flood at a location on a stream that has a certain probability of occurring in any one year. If prolonged periods of rainfall and flooding occur that exceed the design requirements, that structure may be overtopped and fail. Overtopping is the primary cause of earthen dam failure in the United States. Dam failures can also result from any one or a combination of the following causes: • Earthquake • Inadequate spillway capacity resulting in excess overtopping flows • Internal erosion caused by embankment or foundation leakage or piping or rodent activity • Improper design • Improper maintenance • Negligent operation • Failure of upstream dams on the same waterway Water released by a failed dam generates tremendous energy and can cause a flood that is catastrophic to life and property. A catastrophic dam failure could challenge local response capabilities and require evacuations to save lives. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Major loss of life could result as well as potentially catastrophic effects to roads, bridges, and homes. Associated water quality and health concerns could also be issues. Factors that influence the potential severity of a full or partial dam failure are the amount of water impounded; the density, type, and value of development and infrastructure located downstream; and the speed of failure. Controlled release or spillway flooding: inadequate spillway capacity often results in excess overtopping flows, though the potential for flooding as a result of discharge from dam outlet structures or spillways could be expected during excessive rain events. However, controlled releases of water from dams is a measure that can prevent or minimize spillway flooding or structure failure, by regulating capacity in a managed way. Even controlled releases can lead to unwanted or unpredicted flooding, depending on environmental and weather conditions, or even human error. In general, there are three types of dams: concrete arch or hydraulic fill, earth-rockfill, and concrete gravity. Each type of dam has different failure characteristics. A concrete arch or hydraulic fill dam can fail almost instantaneously: the flood wave builds up rapidly to a peak then gradually declines. An earth- rockfill dam fails gradually due to erosion of the breach: a flood wave will build gradually to a peak and then decline until the reservoir is empty. And, a concrete gravity dam can fail instantaneously or gradually with a corresponding buildup and decline of the flood wave. Geographic Area According to the California Department of Water Resources’ Jurisdictional Dams as well as the National Inventory of Dams databases there are dams in the County constructed for flood control, irrigation storage, recreation, and stock watering purposes. The combined state and federal dataset identifies 15 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-138 dams, located in or upstream of the County of San Luis Obispo. Of these dams, ten are considered high hazard, three as significant hazards, one as a low hazard, and one as undetermined hazard. The San Antonio Dam is located just north of San Luis Obispo County, within Monterey County, while Twitchell is on the boundary between Santa Barbara and San Luis Obispo Counties; however, they pose a threat to San Luis Obispo County since they are on drainages that flow into the County. Table 5-48 details the high and significant hazard dams affecting the County of San Luis Obispo. The majority of these dams are in the Salinas and Central Coastal watersheds, with one being located in the Cuyama watershed, all in the central and west portions of the county. Both incorporated and unincorporated areas are at risk of damage from flooding in the event of a dam failure, however, Atascadero, the City of San Luis Obispo, and the central portions of the unincorporated county are at greater risk due to being more largely urban or more directly downstream/below the dams on the valley floor. Besides the 13 high or significant hazard dams noted below, the Las Tablas Creek dam is rated as a low hazard structure, with 180 acre-feet of storage capacity and 37 feet in height, while the Klau Dam is undetermined hazard rating-wise, only having a 50 acre-feet of storage capacity and being 45 feet in height. Table 5-48 County of San Luis Obispo Dams of Concern Characteristics Hazard Rating Dam Name Drainage Downstream Community Dam Type Dam Height (in Feet) Storage Capacity (Acre- Feet) Emergency Operations Plan? High Atascadero Park Tr Atascadero Creek Atascadero Earth 18 250 No High Chorro Creek Chorro Creek Camp San Luis Obispo Earth 77 90 No Significant Eagle Ranch Hale Creek Atascadero Earth 55 300 No Significant Hartzell Santa Rita Creek Atascadero Earth 50 300 Yes High Lopez Arroyo Grande Creek Arroyo Grande Earth 166 52,500 No High Nacimiento Nacimiento River Bradley Earth 255 470,000 Yes High Righetti W Corral De Piedra Edna Earth 83 735 No High Salinas Dam Salinas River Santa Margarita Concrete 135 43,200 Yes High San Antonio San Antonio River Bradley Earth 202 350,000 No Significant San Marcos San Marcos Creek Paso Robles Earth 42 325 Yes High Terminal Tr Arroyo Grande Arroyo Grande Earth 53 844 No High Twitchell Cuyama River Santa Maria Earth 241 398,120 Yes High Whale Rock Old Creek Cayucos Earth 193 40,662 Yes Source: National Inventory of Dams, 2018; California Department of Water Resources – Jurisdictional Sized Dams, 2018 Note: 1 acre-foot = 325,851 gallons Figure 5-44 illustrates the locations of identified dams of concern within the County, including their major drainages, while Figure 5-45 displays the dam inundation areas for eight of the ten high hazard dams in the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-139 Figure 5-44 Dams of Concern to San Luis Obispo County PACIFIC OCEAN Dam Hazard Category • High Significant -'-Low Undetermined --waterwa ys Lakes -+--+ Ra ilroads --High way Free way LJ Cities ••• Map compiled 2/2019; inte nded fo r planning purposes onl y. Data Sou rce: San Luis Obispo County, US Cens us T IG ER Database , CA Open Data Portal , CA DWR , NID 2018 Mont erey 0 10 I i! I Tulare I I _____________ __! _______ ,====== ~ Kern · ~ ~ Santa Barbara Ventura 20 40 Mi les N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-140 Figure 5-45 Dam Inundation Areas in San Luis Obispo County ••• 1 •Vt.u:imfi:m1o~H.c sen·oir ... L AS TAB L AS CREEK HALER 41 Morro Bay PACIFIC OCEAN Dam Hazard Category " ___ J Counties .. H igh I::::: ::I Cities A Sign ificant Dam Inundation Extent .. Low Lopez Dam L U ndetermined -Nacimiento Dam Waterways -Righetti Dam Lakes -Sa linas Dam ~ Railroads -San Anton io Darn ---H ighway ---Freeway -Terminal Dam Twitchell Reservoir Whale Rock Reservoir Map compiled 5/2019; in tended for planning purposes only. Da ta Sou rce: Sa n Luis Obispo County, US Cens us TI GE R Database , CA Open Da ta Portal , NID 2018 , CA DWR ii» t ' 0 Monterey bispo ~E~l)r.~ P EZ Lo1flz La kt ... ~ TERMINAL ", ~ I , I J ( -11,,,,,,,,r,..,,_~ \), 10 Kings i I -~------------------------------------- Kern Santa Barbara 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-141 Extent (Magnitude/Severity) Standard practice among federal and state dam safety offices is to classify a dam according to the potential impact a dam failure (breach) or mis-operation (unscheduled release) would have on downstream areas. The hazard potential classification system categorizes dams based on the probable loss of human life and the impacts on economic, environmental and lifeline facilities. Dams are classified in three categories that identify the potential hazard to life and property: • High hazard indicates that a failure would most probably result in the loss of life; • Significant hazard indicates that a failure could result in appreciable property damage; • Low hazard indicates that failure would result in only minimal property damage and loss of life is unlikely. • Undetermined hazard dams have not been rated or their hazard rating is not known Since the County has several High and Significant hazard dams, there is potential for loss of life and property damage. Both unincorporated and incorporated areas of the County are identified on dam failure inundation maps included in the County’s Dam and Levee Failure Evacuation Plan, last updated on February of 2016, and also displayed in Figure 5-45. The inundation areas for each of the dams are generally downstream and include large rural and urban areas on the valley floor below the dams. Adjacent jurisdictions could also be affected by a dam failure in San Luis Obispo County. These include, depending on the dam involved and to a limited extent, the Counties of Monterey and Santa Barbara. The extent of impacts depends on the nature of failure and location of the dam. The largest populations potentially at risk would be in Arroyo Grande, Grover Beach, Pismo Beach, Paso Robles, and Atascadero. Unincorporated areas across the county, particularly running through the Salinas River, east of the Nacimiento Reservoir, and west of the Twitchell Reservoir, would also be impacted were a dam to fail and flood downstream. Past Occurrences There is no history of dam failure affecting the county, but there have been recurring issues with flooding due to high flows released below dams in the area. Events in 1969, 2006, 2011, 2017, Nacimiento Area/Heritage Ranch Community Service District (HRCSD) - Heavy rains on several occasions have led to flooding, which led to filling of the Nacimiento Reservoir to capacity. High flow releases from the dam by Monterey County Water Resources Agency (MCWRA) was necessary to relieve pressure on the dam. HRCSD’s only potable water system is a fourth of a mile downstream from the dam and has been destroyed once and damaged at least two other times by these high flow releases. The high release in 1969 caused very significant damage to downstream property prior to construction of HRCSD facilities. Destruction of HRCSD Gallery Wells (water system intake facilities) did take place in the 2011 event, and damage of the same on at least two other occasions (2006 and 2017). The District noted costs associated with replacement and repair of infrastructure, additional water treatment necessary to compensate for loss of treatment efficiency due to temporary intake facilities during reconstruction, damage from scour and removal of gallery well filter media during at least two other high flow events (HRCSD 2019 HMP Update Workbook). The replacement value of the water treatment and distribution system is $18.1 million. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-142 Probability of Future Occurrences Unlikely—The County remains at risk to dam failures from numerous dams under a variety of ownership and control and of varying ages and conditions. However, based on historical experience and HMPC input, dam failure is unlikely in the area. Nevertheless, given the number of dams of concern in the County the potential exists for future dam failures in San Luis Obispo County, but the likelihood of this is low. Uncontrolled or controlled release flooding as well as spillway flooding below dams due to excessive rain or runoff are more likely to occur than failures. Climate Change Considerations The potential for climate change to affect the likelihood of dam failure is not fully understood at this point in time. With a potential for more extreme precipitation events a result of climate change, this could result in large inflows to reservoirs. However, this could be offset by generally lower reservoir levels if storage water resources become more limited or stretched in the future due to climate change, drought and/or population growth. Vulnerability A dam incident can range from a small, uncontrolled release to a catastrophic failure. Vulnerability to dam failures is confined to the areas and populations subject to inundation downstream of the facility. Secondary losses would include loss of the multi-use functions of the dam itself and associated revenues that accompany those functions. The Central Coast Tribune News for the County of San Luis Obispo yielded the following information (summarized in Figure 5-46) on potential dam failures and how they would affect nearby communities, based on dam inundation data from the San Luis Obispo County Office of Emergency Services (Tribune Staff, 2017). However, parcel analysis was carried out with the latest datasets from the county as well as assessor’s office improvement values and ParcelQuest provided spatial layers, to overlay each dam inundation layer with the parcels to arrive at total parcels exposed, loss estimates, and populations at risk. The dam inundation areas by high hazard dam in the county are displayed in Figure 5-45 and the results of the parcel analysis explained in more detail in the sections below. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-143 Figure 5-46 Dam Inundation Impacts to Downstream Communities in San Luis Obispo County Templetono .. ,. Atncad /,ale Rock (ayucos Where the water would go if our local dams burst People living in tire populated areas dow11stream from Lopez Lake and Whale Rock Reservoir fac e the biggest risks of damage if a dam failed. NACIMIENTO DAM• Lake Nacimiento Earth-filled dam , 377,900 acre-feet capacity. Most flooding would flow north along the Salinas River in Monterey County ; some water would flow south toward San Miguel. During a major flood , Highway 101 would flood from Camp Roberts through San Ardo . WHALE ROCK DAM• Whale Rock Reservo ir Earth-filled dam, 40,600 acre feet capacity. In a dam failure. wate r would flow southwest along Old Creek, about 1,000 feet on eac h side of the creek 's center line. reaching 13th Street and Ocean Avenue in Cayucos. About 1,500 people would be affected , as would the Cayucos Water Treatment Pla nt. Highway 1 may flood . SAUNAS DAM • Santa Marga rita Lake Concrete dam, 23,000 acre feet capacity. In a dam failure , water wou ld flow north along t he Salinas River abo ut 300 to 500 feet on each side of the center li ne of the river and into fingers in low-lying areas up to Atascadero . Significant water rise is not expected . About 1,000 to 2,000 people cou ld be affected . Major SOURCE : San Luis Obispo County Office of EmergencvServtces ••• I 41 41 •(hol ame Areas that could flood in the event of a dam failure 58 r1 T,vj,cl,t// Reservoir \ maps4 ~ com/ RE roads flooded may inc lude Las Pilitas Road ; Highways 41 , 46. 58 , 101; In dian Valley Road ; North River Road near Paso Robles ; and Main Street in Templeton . LOPEZ DAM • Lopez Lake Earth-filled dam, 49,000 acre feet capacity. In a dam failure, water would flow west following Arroyo Grande Creek and could flood about 3,000 feet -or more than half a mile -on eac h side of the creek's center line, About 10,000 to 12 ,000 people could be affected in Arroyo Grande , Grover Beach , Halcyon. Oceano and Pismo Beach . Floodwaters could reach Huasna Road in 30 minutes and Highway 101 in 40 minutes. TWITCHELL DAM• Twitchell Reservoir Earth -filled dam, 240,100 acre feet capacity. In a dam and levee failure , most flooding would occur in Santa Barbara County. About 100 to 160 people could be affected in the Oso Flaco area . Major roads flooded co uld include Highway 1 near the SLO County line. BETH ANDERSON banderson lhe tnbunenews,c MONI CA VAUGHAN mvaughan@thetribunenews.c Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-144 General Property In general, communities located below a high or significant hazard dam and along a waterway are potentially exposed to the impacts of a dam failure. For reference, high hazard dams threaten lives and property, significant hazard dams threaten property only. Inundation maps that identify anticipated flooded areas (which may not coincide with known floodplains) are produced for all high hazard dams and are contained in the Emergency Action Plan (EAP) required for each dam. A GIS layer that contained inundation maps for eight of the ten high hazard dams that affect the County was analyzed to quantify risk across the planning area. Table 5-49, Table 5-50 and Table 5-51 summarize the estimated losses calculated from tallying up the parcels’ improved and content values (more details on the parcel analysis methodology under the Asset Summary section). The loss estimate percentage used for dam failure inundation is 50% of a parcel’s total value. Figure 5-47 displays the parcels found to overlay with the dam inundation layer. According to the analysis of the dams with a potential to impact the planning area the Lopez Dam has the greatest potential downstream impacts coupled with a relatively short time to evacuate downstream areas. The Whale Rock, Salinas, and Twitchell dams also pose significant threats should a failure occur. Some jurisdictions are more at risk to dam failure than others. The cities of Arroyo Grande, Grover Beach, portions of the unincorporated areas are the most vulnerable. Atascadero, Pismo Beach, and Paso Robles also have a high hazard dams located upstream of them. The failure of any of these dams would cause downstream flooding and would likely result in loss of life and property. The potential magnitude of a dam failure depends on the time of year and the base flow of the river when the failure occurs. During the winter months, when the river flows are higher, the impact to the area would be much greater and evacuation times even shorter. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-145 Figure 5-47 Parcels Within Dam Inundation Areas in San Luis Obispo County PACIFIC OCEAN Parce ls W ithin Dam Inundation Areas -+-- • Parcels Dam Inundation Extent Lopez Dam Nacimiento Dam Highway Freeway Lakes Righe tt i Dam waterways D eiti es [-.:J Co unties ••• Twitche ll Reservoir \/Vhale Rock Reservo ir Map compi led 3/2019: intended for planning purposes on ly. Data Source: Sa n Lu is Obispo Cou nty, US Census TIGER Database , CA Open Data Portal , ParcelQuest 0 10 20 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-146 Table 5-49 Dam Inundation Estimated Losses by Jurisdiction and Dam Jurisdiction Dam Parcel Count Improved Value Content Value Total Value Loss Estimate Population Arroyo Grande Lopez 3,565 $681,052,289 $356,141,266 $1,037,193,555 $518,596,777 8,273 Atascadero Salinas 181 $28,803,852 $16,315,428 $45,119,280 $22,559,640 399 Grover Beach Lopez 2,392 $417,358,957 $217,731,586 $635,090,543 $317,545,272 5,319 Paso Robles Salinas 68 $34,219,768 $22,658,110 $56,877,878 $28,438,939 58 Pismo Beach Lopez 66 $33,076,320 $15,020,878 $48,097,198 $24,048,599 113 Unincorporated Lopez 2,333 $362,698,180 $181,512,103 $544,210,283 $272,105,141 5,125 Nacimiento 7 $144,774 $69,426 $214,200 $107,100 3 Righetti 16 $12,694,743 $6,339,437 $19,034,180 $9,517,090 38 Salinas 116 $19,560,321 $9,493,807 $29,054,128 $14,527,064 201 Terminal 11 $2,336,587 $1,157,154 $3,493,741 $1,746,870 20 Twitchell 224 $37,806,448 $22,799,265 $60,605,713 $30,302,856 183 Whale Rock 643 $129,036,238 $64,260,893 $193,297,131 $96,648,565 1,556 Lopez 3,565 $681,052,289 $356,141,266 $1,037,193,555 $518,596,777 8,273 TOTAL 9,622 $1,758,788,477 $913,499,350 $2,672,287,827 $1,336,143,914 21,287 Source: San Luis Obispo County Planning and Building Dept., Assessor’s Office, ParcelQuest, Wood Plc Parcel Analysis Table 5-50 Dam Inundation Estimated Losses by Property Type Property Type Parcel Count Improved Value Content Value Total Value Loss Estimate Population Agricultural 101 $14,469,017 $14,469,017 $28,938,034 $14,469,017 -- Commercial 314 $105,608,490 $105,608,490 $211,216,980 $105,608,490 -- Government/Utilities 227 $75,984 -- $75,984 $37,992 -- Other/Exempt/Misc. 379 $60,173,041 -- $60,173,041 $30,086,521 -- Residential 6,627 $1,145,400,771 $572,700,386 $1,718,101,157 $859,050,578 16,634 Multi-Family Residential 999 $223,706,043 $111,853,022 $335,559,065 $167,779,532 2,507 Mobile/Manufactured Homes 55 $33,945,009 $16,972,505 $50,917,514 $25,458,757 138 Residential: Other 800 $150,192,292 $75,096,146 $225,288,438 $112,644,219 2,008 Industrial 27 $11,199,857 $16,799,786 $27,999,643 $13,999,821 -- Vacant 93 $14,017,973 -- $14,017,973 $7,008,987 -- TOTAL 9,622 $1,758,788,477 $913,499,350 $2,672,287,827 $1,336,143,914 21,287 Source: San Luis Obispo County Planning and Building Dept., Assessor’s Office, ParcelQuest, Wood Plc Parcel Analysis Table 5-51 Dam Inundation Estimated Losses by Dam Dam Parcel Count Improved Value Content Value Total Value Loss Estimate Population Lopez 8,356 $1,494,185,746 $770,405,832 $2,264,591,578 $1,132,295,789 18,830 Nacimiento 7 $144,774 $69,426 $214,200 $107,100 3 Righetti 16 $12,694,743 $6,339,437 $19,034,180 $9,517,090 38 Salinas 365 $82,583,941 $48,467,345 $131,051,286 $65,525,643 658 Terminal 11 $2,336,587 $1,157,154 $3,493,741 $1,746,870 20 Twitchell 224 $37,806,448 $22,799,265 $60,605,713 $30,302,856 183 Whale Rock 643 $129,036,238 $64,260,893 $193,297,131 $96,648,565 1,556 TOTAL 9,622 $1,758,788,477 $913,499,350 $2,672,287,827 $1,336,143,914 21,287 Source: San Luis Obispo County Planning and Building Dept., Assessor’s Office, ParcelQuest, Wood Plc Parcel Analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-147 Dam failure flooding would vary by community depending on which dam fails and the nature and extent of the dam failure and associated flooding. Based on the risk assessment, it is apparent that a major dam failure could have a devastating impact on the planning area. Dam failure flooding presents a threat to life and property, including buildings, their contents, and their use. Large flood events can affect crops and livestock as well as lifeline utilities (e.g., water, sewerage, and power), transportation, jobs, tourism, the environment, and the local and regional economies. People Persons located underneath or downstream of a dam are at risk of a dam failure, though the level of risk can be tempered by topography (specifically where populations are located within the inundation path of a dam), amount of water in the reservoir and time of day of the breach. Injuries and fatalities can occur from debris, bodily injury and drowning. Once a dam has breached, standing water presents all the same hazards to people as floodwater from other sources. People in the inundation area may need to be evacuated, cared for, and possibly permanently relocated. Impacts could include thousands of evacuations and likely hundreds of casualties, depending on the dam involved. Specific population impacts are noted in Table 5-49, Table 5-50, and Table 5-51, and total people at risk were calculated by multiplying the average number of persons per household in the county of San Luis Obispo (2.51) times the number of residential parcels where dam inundation occurs. An incident at the Lopez dam would potentially put the most people at risk, followed by the Whale Rock and Salinas dams. Social Vulnerability The inundation paths of the Lopez and Salinas dams not only put the most people at risk, they will also potentially impact the communities of Grover Beach (Lopez dam) and Paso Robles (Salinas dam). Both communities are among the areas with the highest ranking of overall social vulnerability in the county based on the SoVI data presented and discussed in subsection 4.4.1. Public outreach and education on dam incidents as well as ensuring alert and warning systems are working properly should be focused in these areas. Critical Facilities A total dam failure can cause catastrophic impacts to areas downstream of the water body, including critical infrastructure. Any critical asset located under the dam in an inundation area would be susceptible to the impacts of a dam failure. Of particular risk would be roads and bridges that could be vulnerable to washouts, further complicating response and recovery by cutting off impacted areas. Risk to specific facilities could be considered sensitive information additional details can be found within the San Luis Obispo County’s Dam and Levee Failure Evacuation Plan, updated as of February 2016. Table 5-52 summarizes the number and types of critical facilities found to be at risk of dam failure incidents from the Lopez and Nacimiento Lake Dams, given no other dams’ inundation extents cross the path of key facilities or structures in the county. These results were found by performing overlay analysis of the critical facilities and the dam inundation layers in GIS. Most of these facilities at risk (13) are found in Arroyo Grande, with another 13 in the unincorporated portions of the county and 8 in Grover Beach. Overall, a total of 34 critical facilities are found within dam inundation zones across the county. Note that 33 of the 34 critical facilities found in dam inundation areas fall under the Lopez Dam extents, while only 1 (a water treatment facility in the Heritage Ranch Community Services District, in the unincorporated portion of the County, falls under the Nacimiento Lake Dam inundation extent). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-148 Table 5-52 Critical Facilities in the Lopez Dam and Nacimiento Lake Dam Inundation Areas, by Type of Facility and Dam Name Jurisdiction Critical Facility Type Count ARROYO GRANDE Day Care Facilities 3 Emergency Medical Service Stations 1 Fire Stations 1 Hospitals 2 Nursing Homes 2 Private Schools 1 Public Schools 3 TOTAL 13 GROVER BEACH Day Care Facilities 2 Microwave Service Towers 2 Private Schools 1 Public Schools 2 Water Treatment Facilities 1 TOTAL 8 UNINCORPORATED Day Care Facilities 4 Emergency Medical Service Stations 1 Fire Stations 1 Local Law Enforcement 1 Public Schools 1 Wastewater Treatment Plant 1 Airport 1 Energy Commission Facilities 1 Water Treatment Facilities (1 in Lopez Dam area and 1 in Nacimiento Lake Dam area) 2 TOTAL 13 GRAND TOTAL 34 Source: San Luis Obispo County Planning & Building Department, HIFLD, San Luis Obispo County Community Services Districts, Wood GIS analysis Economy Extensive and long-lasting economic impacts could result from a major dam failure including the long- term loss of water in a reservoir after a failure event. A major dam failure and loss of water from the associate reservoir could include direct business and industry damages and indirect disruption of the local economy. Historic, Cultural, and Natural Resources Dam failure effects on the environment would be similar to those caused by flooding from other causes. Water could erode stream channels and topsoil and cover the environment with debris. For the most part the environment is resilient and would be able to rebound from whatever damages occurred, though this process could take years. However, historic and cultural resources could be affected just as housing or critical infrastructures would, were a dam to fail and cause downstream inundation that could further ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-149 erode surfaces or cause scouring of structural foundations. GIS analysis indicates the following 3 historic properties are potentially at risk to dam inundation. Table 5-53 Historic and Cultural Properties in Dam Inundation Areas, San Luis Obispo County Name Year Area Plan Dam Causing Inundation Southern Pacific Railroad Depot -- San Luis Bay Area Plan-Inland Lopez Coffee T. Rice House 1886 San Luis Bay Area Plan-Coastal Lopez Temple of The People, Halcyon 1903 San Luis Bay Area Plan-Inland Lopez Source: County of San Luis Obispo Planning and Building Dept., 2019 Future Development Areas slated for future development should take into consideration potential impacts from dam failure risk upstream and should attempt to overlay the existing dam inundation maps with proposed future development. In the case of a dam failure, inundation would likely follow some existing FEMA mapped floodplains, which contains development restrictions for areas in the 1% annual chance floodplain, but it could exceed those floodplains and affect areas that are not regulated for flood hazards. Also of note is that development below a low or undetermined hazard dam could increase its hazard rating, though there is only one low hazard and one undetermined hazard dam in the County (while the majority are high or significant hazard dams). Finally, added development could compromise dams and reservoir resources if populations depend on them for critical needs such as potable water during or after a dam failure event. For example, the Nacimiento Reservoir is the only source of potable water within the Heritage Ranch Community Services District, and were this reservoir and dam to fail, the growing residential population would be potentially affected by dam inundation, resource damages, and lack of necessary potable water. For this plan, a GIS overlay analysis of building construction permits for residential and commercial properties was additionally performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties (a total of 333) may be constructed, or may have upgrades done, within dam inundation areas (see Table 5-54). More detail on the specific types of permits granted, particularly the kind of work class and case type for each permit group, can be found under the Asset Summary section of this plan. Table 5-54 Building Permits Submitted in Dam Inundation Areas from 2014-2019 Work Class Case Type Work Class Type Total Conditional Use Permit Land Use 24 Minor Use Permit 106 New Structure PMTC - Commercial Permit 43 PMTR - Residential Permit 160 TOTAL 333 Source: San Luis Obispo County Planning & Building Department, Wood GIS analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-150 Risk Summary The overall significance of dam inundation in San Luis Obispo County is Medium. • Based on historical evidence dam failures can happen and flood downstream communities in the county, though not frequently. • Effects on property: Countywide there are 9,622 parcels at risk, worth $2.67 million, with a loss estimate of $1.33 million. The Unincorporated areas account for 35% of the total structures at risk, and about 32% of the total estimated losses. The Lopez dam puts the most parcels at risk of dam inundation, with 8,356 county-wide (most in Arroyo Grande), followed by the Salinas and Whale Rock dams. However, besides Arroyo Grande, the most parcels at risk of various high hazard dam failures are Grover Beach and the unincorporated areas of the county. Residential structures make up the most parcels at risk of flooding from dam failures (including multi-family residential, other residential parcels, and mobile/manufactured homed), followed by exempt/miscellaneous/government/utilities parcels and commercial parcels. • Effects on people: People are vulnerable to dam failure in San Luis Obispo County. An estimated 21,287 people might be displaced from their homes based the location of their residences along the inundation areas. • Effects on critical facilities and infrastructure: GIS analysis yielded that 33 critical facilities are found within the Lopez Dam’s inundation area, with 1 additional falling in the Nacimiento Lake Dam inundation area (within the Heritage Ranch Community Services District) for a total of 34 critical facilities at risk of this hazard. A total of 13 of those in Arroyo Grande, 13 in the unincorporated areas of the county, and 8 facilities in Grover Beach. • Effects on economy: Dam inundation can disrupt transportation corridors, affecting the economy by impeding or reducing flows of goods, people, and resources. • Related Hazards: adverse weather, flooding, earthquake/liquefaction, tsunami/seiches, land subsidence, landslide, drought. Table 5-55 Dam Inundation Risk Summary by Jurisdiction Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Limited Occasional Critical Medium City of Arroyo Grande Extensive Unlikely Catastrophic Medium City of Atascadero Limited Unlikely Limited Low City of Grover Beach Extensive Unlikely Catastrophic Medium City of Morro Bay Limited Unlikely Negligible Low City of Paso Robles Significant Occasional Limited Low City of Pismo Beach Limited Occasional Critical Medium City of San Luis Obispo N/A Avila Beach CSD Limited Unlikely Limited Low Ground Squirrel Hollow CSD Limited Unlikely Limited Low Heritage Ranch CSD Extensive Likely Catastrophic High ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-151 Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance Los Osos CSD N/A Nipomo CSD Limited Unlikely Limited Low San Miguel CSD Limited Unlikely Negligible Medium San Simeon CSD N/A Templeton CSD Significant Occasional Limited Low Cayucos Sanitary District Limited Unlikely Limited Low Port San Luis Harbor District Limited Unlikely Negligible Low San Luis Obispo FCWCD Limited Occasional Critical Medium South San Luis Obispo Sanitary District Extensive Unlikely Catastrophic Medium ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-152 5.3.9 Drought and Water Shortage Hazard/Problem Description Drought is a gradual phenomenon. Although droughts are sometimes characterized as emergencies, they differ from typical emergency events. Most natural disasters, such as floods or forest fires, occur relatively rapidly and afford little time for preparing for disaster response. Droughts occur slowly, over a multi-year period, and it is often not obvious or easy to quantify when a drought begins and ends. Drought is a complex issue involving many factors—it occurs when a normal amount of moisture is not available to satisfy an area’s usual water-consuming activities. Drought can often be defined regionally based on its effects: • Meteorological drought is defined by a period of substantially diminished precipitation duration and/or intensity. The commonly used definition of meteorological drought is an interval of time, generally on the order of months or years, during which the actual moisture supply at a given place consistently falls below the climatically appropriate moisture supply. • Agricultural drought occurs when there is inadequate soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought usually occurs after or during meteorological drought, but before hydrological drought and can affect livestock and other dry-land agricultural operations. • Hydrological drought refers to deficiencies in surface and subsurface water supplies. It is measured as stream flow, snow pack, and as lake, reservoir, and groundwater levels. There is usually a delay between lack of rain or snow and less measurable water in streams, lakes, and reservoirs. Therefore, hydrological measurements tend to lag behind other drought indicators. • Socio-economic drought occurs when physical water shortages start to affect the health, well-being, and quality of life of the people, or when the drought starts to affect the supply and demand of an economic product. The California Department of Water Resources (DWR) says the following about drought: “One dry year does not normally constitute a drought in California. California’s extensive system of water supply infrastructure—its reservoirs, groundwater basins, and inter-regional conveyance facilities—mitigates the effect of short-term dry periods for most water users. Defining when a drought begins is a function of drought impacts to water users. Hydrologic conditions constituting a drought for water users in one location may not constitute a drought for water users elsewhere, or for water users having a different water supply. Individual water suppliers may use criteria such as rainfall/runoff, amount of water in storage, or expected supply from a water wholesaler to define their water supply conditions.” The drought issue in California is further compounded by water-rights. Water is a commodity possessed under a variety of legal doctrines. The prioritization of water rights between farming and federally protected fish habitats in California is part of this issue. Drought impacts are wide-reaching and may be economic, environmental, and/or societal. The most significant impacts associated with drought in the planning area are those related to water intensive activities such as agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. Also, during a drought, allocations go down, which results in reduced water availability. Voluntary water conservation measures are typically implemented during extended droughts. A reduction of electric power generation and water quality deterioration are also potential problems. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-153 Drought conditions can also cause soil to compact and not absorb water well, potentially making an area more susceptible to flooding. Geographic Area Drought is a regional hazard, and at its worst can affect the entire state of California with varying levels of dryness and drought activity (as will be covered in more detail under the sections to follow). It is safe to assume that unless the drought event is at its very beginning or very end, if any area of the County of San Luis Obispo is affected by any level of drought, the other areas of the county are experiencing varying effects as well. The San Luis Obispo Integrated Regional Water Management Plan (2014) organized the County into sixteen Water Planning Areas), “intended to recognize important hydrogeologic units or water management areas throughout the County” (IRWM, 2014). As this plan was being written the County’s Integrated Regional Water Management Plan was also in the process of being updated. The update to the IRWMP revised to the number of Water Planning Areas to six and aligned them with the USGS watershed boundary datasets, refer to Figure 5-48 below. The major water supply for all of the Water Planning Areas (WPA) come from groundwater sources and minor supplies from surface water sources such as the Salinas and Estrella Rivers. During periods of drought there is an increased demand for groundwater resources. This being the case, in addition to groundwater sources most of the WPAs also receive water supplies from other sources such as, the State Water Project, Nacimiento Water Project and Reservoirs (Whale Rock, Chorro, Lopez Lake, Salina). Some communities have gone beyond groundwater and surface water supplies and have developed recycled water programs (City of San Luis Obispo and City of Pismo Beach) for the purposes of irrigating landscaping or control dust on construction sites. The City of Morro Bay has also implemented a desalination project. Drought impacts are an issue for all of the Water Planning Areas. Sustainable Groundwater Management Act of 2014 Then Central Coast region and all of California have been experiencing significant drought and water shortages since 2011. Only recently as of February 2019 did the County and the majority of the state come out of drought. In January 2014 the Governor declared an emergency proclamation due to multiple years of drought. The proclamation called on citizens to reduce water use by 20 percent; with a subsequent executive order in April 2015 that directed urban water agencies to reduce water use by 25 percent (Ken Topping, 2016). In September 2014, the Governor signed a three-bill package (California Senate Bills 1168 and 1319, and Assembly Bill 1739), known as the Sustainable Groundwater Management Act of 2014 (SGMA). The SGMA provides for the establishment of local Groundwater Sustainability Agencies (GSAs) to manage groundwater sustainability within the groundwater subbasins defined by the California Department of Water Resources (DWR). The DWR prioritized all groundwater basins in the state designating High and Medium priority basins. High or medium priority basins are subject to critical conditions of overdraft are required to submit a Groundwater Sustainability Plan (GSP) by January 31, 2020. The purpose of the GSP to ensure a sustainable yield of groundwater, without causing undesirable results. The deadline to submit a GSP for high or medium priority basin not subject to critical conditions of overdraft is January 31,2022. Failure to comply with that requirement could result in the State asserting its power to manage local groundwater resources. The State has identified the following five high and medium priority groundwater basins within San Luis Obispo County: ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-154 1. Paso Robles (Priority Pending) 2. Santa Maria (Priority Pending) 3. Los Osos (Priority Pending) 4. San Luis Obispo (Edna) Valley (High) 5. Cuyama Valley (High) 6. Atascadero (Very Low) ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-155 Figure 5-48 San Luis Obispo County Water Planning Areas Source: San Luis Obispo Public Works, Water Resources Division ••• C: (1l Q.) (.) 0 ~ ~ Kern County, V lit County of San Luis Obispo Public W orks Water Resou rces Water Planning Areas and Groundwater Basins Legend Highways =US HI G HWAY --STATE HIGHWAY Q CityLimlts □ 2018 water Plann ing Area /Y'IPA)' Cal ifornia Departmen t of Water Resources Bu lleti n 118 Grou ndwater Basins Water Planning Areas (WPA): W PA 3 San Luis Obispo I South County WPA 6 Carrizo Plai n 1. Based o n the drafl: 2018 Integrated Regional 1/-.aler Management (IRWM) Plan update (http://sJocountyw-ater.org{lfWlll) N A --==---•" Date Created: 3/28/2019 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-156 Extent (Magnitude/Severity) The U.S. Drought Monitor is an accepted and widely used site for obtaining and summarizing drought information, as it integrates data from several other sources including the Palmer Drought Index, Soil Moisture Models, U.S. Geological Survey Weekly Stream Flows, Standardized Precipitation Index, and the Satellite Vegetation Health Index. It includes drought intensity categories for measuring dry conditions across counties, states, and regions of the U.S., so that drought can be quantified. These categories range from “abnormally dry” to “exceptional drought.” The following figures provide “snapshots in time” of the drought conditions in California as of March 2019, February 2019, and August 2015 (during the period of the last multi-year drought in San Luis Obispo County and the state, from 2012- 2017). The snapshots selected are instrumental in depicting both the historic and potential change in drought’s geographic range and severity in the County (circled in blue). Due to severe winter storms that brought heavy rains in February and March 2019, the County for the first time since 2011 is no longer experiencing dryness or drought (San Luis Obispo Tribune 2019). Note: The Drought Monitor maps integrate data from several sources including the Palmer Drought Index, Soil Moisture Models, U.S. Geological Survey Weekly Stream flows, Standardized Precipitation Index, and Satellite Vegetation Health Index. Figure 5-49 U.S. Drought Monitor for California: March 7, 2019 U.S. Drought Monitor California ••• March 5, 2019 (Released Thursday, Mar. 7, 2019) Valid 7 a.m. EST Drought conditions (Percent Area) None D0-D4 D1-D4 D2-0 4- Current 89.84 10.16 0.60 0.00 0.00 0.00 Last Week 02-26-2019 87 .17 12.83 233 0.00 0.00 0.00 3 Mo nths Ago 12-04-2018 777 92.23 79 .69 18 .34 3.78 0.00 Start o f Ca lendar Year 777 92.23 75.17 14.1 2 2. 10 0.00 0 1-01-2019 start or V\hter Year 12.18 87.82 47 .97 22 .82 494 0.00 09-25-2018 One Year Ago 8.48 91 .52 47 .87 22 .40 0.43 0.00 03--06-2018 Intensity: DO Abno rma lly Dry -D3 Extreme Drought D1 Moderate Drought -D4 Exceptional Drough t D2 Se ve re Drought The Drought Monitor focus es on txo ad-scale conditions. Local cond;tions may vary. See accompanyin g text summary tor rorec asr st aremenrs. Author.- Eric Lueoe hu se n U.S . Department of Agriculture USDA =□ http :1/d roughtmonitor.u nl.edu/ Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-157 Figure 5-50 U.S. Drought Monitor for California: February 5, 2019 U.S. Drought Monitor California ••• February 5, 2019 (Re leased Thu rsday, Feb. 7, 2019) Valid 7 a.m . EST Drought Condiuons (Pe rcent Area) None D0-O4 01-04 02-04111 11 Current 34 .37 65.63 10.55 1.89 0 00 0.00 Last Week 01-2 S-2 019 23 .93 76 .07 23 .66 1.89 0 00 0.00 3 Months Ago 0.00 100.00 51.92 18.35 239 0.00 11-06-2018 St art of Ca lendar Yea r 7.77 92.23 75.17 14.12 2 10 0.00 01-01 -2 019 St art of Wlt er Year 12.18 87 .82 47 .97 22 .82 4.94 0.00 09-25-20 18 One Year Ago 18 .27 81.73 45.60 6.39 0 00 0.00 02-06-2018 Intensity: DO Ab no rma ll y Dry -03 Extreme Drought 01 Mode ra te Drought -04 Exceptional D rought -0 2 Se vere Drought The Drought Monitor f ocuses on broad-scale c ondlions. Loc al conditions may vary: See accompany ing text summary for forec ast statements. Author: Ric na rd Ti nker C PC/N OAA/N WS/N C EP USDA = http :/Id roughtmonitor.u n l. edu / Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-158 Figure 5-51 U.S. Drought Monitor for California: August 4, 2015 Past Occurrences Historically, California has experienced multiple severe droughts. California’s most recent multi-year drought occurred from 2012-2017 as previously mentioned, but the driest single year of California’s measured hydrologic record was 1977. The following multi-year droughts were identified as having significant impacts on the planning area: • 1929 – 1934 – This statewide drought established the criteria commonly used in designing storage capacity and yield for large Northern California reservoirs, and is hence one of the first major historic droughts noted in California. • 1975-1977 — From November 1975 through November 1977, California experienced one of its most severe droughts. Although people in many areas of the state are accustomed to very little precipitation during the growing season (April to October), they expect it in the winter. In 1976 and 1977, the winters brought only one-half and one-third of normal precipitation, respectively. Most surface storage reservoirs were substantially drained in 1976, leading to widespread water shortages when 1977 turned out to be even drier. Thirty-one counties were affected, resulting in $2.67 billion in crop damage. U.S. Drought Monitor Ca ifo ni a ••• A.ugus.t 4 2015 (R,@f, ~d Th rrsday, Aug. 6, 201 J V3li B a.m. EDT DO -1 ~-Omqll cm;qs ·~DIIIUIJI ~~t ~Wf~lffi:iCilfl~' ~" Loca coooitxxls may r<iT'f. See ~.ng,1&1 lmlal)'ibr/~ Ulbor: -S'",oCro;i Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-159 • 1987-1992 — San Luis Obispo County also suffered adverse effects resulting from this statewide drought, when low precipitation and runoff levels hit the Central Coast the hardest, adversely affecting about 30% of the state’s population, much of the dry-farmed agriculture, and over 40 percent of the irrigated agriculture. Fish and wildfire suffered as well, as did the recreation and hydroelectric production sectors. Forestry losses and fires were very high. • 2007 – 2009 – California proclaimed a statewide drought in 2009, and unprecedented restrictions were placed on water diversions to protect fish species, exacerbating drought impacts for water users. The greatest impacts of this multi-year drought were suffered on the western side of the San Joaquin Valley, on agricultural communities where drought effects were coupled with the economic recession. Emergency response actions were necessary with regards to social services. • 2012 – 2017 – Drought produced severe impacts to water wells throughout the planning area, with a high number of wells running dry. Land subsidence due to increased groundwater pumping also occurred in areas of the San Joaquin Valley close to the Central Coast counties. Crop damage was widespread as well. Water allotments were drastically reduced in many towns and water agencies, with extremely high costs for procuring water. In addition, job loss occurred with many families requiring food supply assistance, and water supply assistance provided to home owners with dry wells. According to a report released by UC Davis Center for Watershed Sciences, the 2014 California drought cost the state's agriculture industry about $1 billion in lost revenue, with a total statewide economic cost of the drought calculated to be $2.2 billion. The 2014 drought, the report says, is responsible for the greatest water loss ever seen in California agriculture - about one third less than normal. The report calls the groundwater situation in California "a slow-moving train wreck." (Source: https://statesummaries.ncics.org/ca). On March 11, 2014 the San Luis Obispo County Board of Supervisors proclaimed a local emergency which lasted for three years until the Board adopted a resolution on May 23, 2017 to end the local emergency. As noted above, the Governor proclaimed a State of Emergency due to drought conditions and the related wide-ranging impacts. The Governor’s proclaimed State of Emergency due to drought covered a similar period, from January 17, 2014 to April 7, 2017. For the County of San Luis Obispo there were 13 disaster declarations from 2012-2017, though total associated financial losses across the various economic sectors is not available for all these recent drought-related declarations. The following table summarizes both state and federal proclamations related to drought affecting the County of San Luis Obispo. Table 5-56 Summary of Secretarial and Governor Disaster Declarations for Drought in San Luis Obispo County Hazard Type Disaster # Year State Proclamation Federal Declaration Damage Drought - 1976 2/1976, 3/1976, 7/1976 Not declared $ 2,664,000,000 Drought EM-3023 1977 -- 1/20/1977 -- Drought - Fast Track S3268 2012 2/21/2012- 5/14/2012 (begin to end) 7/12/2012 (Sec. approval) -- Drought S3379 2012 1/1/2012 9/5/2012 -- Drought S3452 2012 -- 12/19/2012 -- ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-160 Hazard Type Disaster # Year State Proclamation Federal Declaration Damage Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3491 2013 1/1/2013 2/27/2013 -- Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3497 2013 1/15/2013 3/13/2013 -- Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3504 2013 2/12/2013 4/10/2013 -- Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3542 2013 4/23/2013 6/19/2013 -- Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3626 2014 1/1/2014 1/15/2014 -- Drought S3743 2014 1/1/2014 9/17/2014 -- Drought Local Emergency March 11, 2014- May 23, 2017 -- -- -- Drought (Fast Track) Excessive Heat; insects S3784 2015 1/1/2015 2/4/2015 -- Drought S3943 2015 1/2/2015 12/23/2015 -- Drought (FAST TRACK) Wind, Fire, Excessive heat, insects S3952 2016 1/1/2016 2/17/2016 -- Drought - Fast Track S4144 2017 1/1/2017 2/23/2017 -- Drought – Fast Track S4467 2018-2019 10/1/2018 3/6/2019 -- Source: USDA Secretarial Disaster Declarations, 2019; FEMA Disaster Declarations, 2019, HMPC. Figure 5-52 graphically displays the amount of drought-related reported impacts to San Luis Obispo County (United States Drought Impact Reporter 2019). While it is difficult to extract the specific impacts affecting the planning area, a total of 124 reports were submitted at the County level between January 1, 1990 and February 11, 2019. It is assumed that these drought related impacts for areas across the County are likely to have also affected the jurisdictions and communities at some point or to some extent. Based on the summary of negative effects to the county since 1990 the categories of water supply/quality as well as relief/response/restrictions have had the most reports, followed by the agriculture sector and society/public health. Other sectors such as “plants and wildlife” have also suffered the effects of drought but to smaller extents. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-161 Figure 5-52 Drought Impact Reporter Summary of Impacts at the County Level in San Luis Obispo County, 1990-Febuary 2019 Source: National Drought Mitigation Center - Drought Impact Reporter, 2019 Probability of Future of Drought Occurrences Likely —Historical drought data for the County planning area and the Central Coast region indicate there have been five significant multi-year droughts in the last 90 years. This equates to a multi-year drought every 18 years on average, or a 5.5 percent chance of a drought in any given year. Based on this data, droughts will likely affect the planning area. Given the historical occurrence of severe drought impacts throughout San Luis Obispo County and across the state (summarized in the Past Occurrences section of this section), the HMPC understands that drought will continue to pose a high degree of risk to the entire planning area, potentially impacting crops, livestock, water resources, the natural environment at large, buildings and infrastructure (from cascading or compound hazards), and local economies. ~ NATIONAL OROUGHT MITIGATION CENTER Impacts I San Luis Obispo County, CA 01-01-1990 -0 2 -11-20 1 9 County Impacts Categor Ag ricu lt ure Business & I ndust ry Ener gy Fi re Plants & Wi ld lif e Re.lief , Res po nse & Restri ction s Socie t y & Public Heal t h T ourism & Recre at ion Wat er Supply & Qu al ity User other Agency CoC oRaHS Legacy ••• 124 I I m pa cts Li st 31 12 4 11 29 53 31 7 6 2 10 2 2 5 1 16 .. ., Impa cts Opacity ----------------80%. Impact s -0 59 -112 1 13 -165 -166-218 -2 19-27 1 -272-324 ► -Reports ► .....i D rought Decl arat ions •Time Peri od I c ustomize St art : 10 1-0 1-19 9 0 End : 10 2-11-20 19 [ • Locat_i o_n __________ _ 11 ---------------~ St ate: Ca li forn ia County : San Lu is Ob is c • I ► Categ ories Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-162 In addition, although drought affects the entire planning equally, the potential impacts may be variable and specific to each jurisdiction, depending on contextual factors such as the degree of assets and activities historically impacted by drought within each jurisdiction, such as the agricultural and parks and tourism industries. Climate Change Considerations Scientific studies prepared for various California climate assessments and adaptations strategies show that drought conditions in California are likely to become more frequent and persistent over the next century due to climate change. Temperatures are warming, heat waves are more frequent, and precipitation has become increasingly variable (California Natural Resources Agency 2018). Water resources are also already experiencing the following stresses: population growth, poor water quality, groundwater overdraft, and aging water infrastructure. According to California’s Climate Adaptation Strategy, also referred to as “Safeguarding California Plan: 2018 Update”, climate change is likely to significantly diminish California’s future water supply. As a result the state must change its water management, as climate change will create greater competition for limited water supplies (California Natural Resources Agency 2018a).The recent drought conditions over the past decade underscore the need to examine water supply and distribution management, conservation, and use policies. California and the Central Coast region have experienced a succession of dry spells and with warmer temperatures and periodic droughts that frequently contribute to water shortages in the region. Climate change projections of extreme prolonged droughts will exacerabte the Central Coast’s existing water supply challenges (Fourth Climate Change Assessment, 2018). In an average year, approximately 40 percent of the state’s total water supply comes from groundwater, and during a dry year this increases to more than half of the state’s water supply, with groundwater acting as a critical buffer against the impacts of drought and climate change (California Natural Resources Agency 2018). Table 5-57 Summary of Climate Change Impacts on Water Resources Resource Type of Impact Description Sea Level Direct Sea level is rising and will likely impact coastal areas Soil Moisture Direct Prolonged dry seasons can lead to decreases in soil moisture; drier vegetation Vegetation Indirect Longer and more intense fire season with increased extent of area burned Stream Conditions Direct Increases in water temperature; potential effects on fish Snowpack Indirect Increases in temperature will lead to decreases in snowpack Runoff Direct Warmer temperatures are likely to lead to a shift in peak runoff from spring to winter and a likely decrease in summer baseflow Hydropower Indirect Decreased summer flows resulting from earlier snowmelt and a shift in peak runoff could affect hydropower generation during summer months ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-163 Resource Type of Impact Description Precipitation Direct Warmer winter temperatures will result in a greater percentage of precipitation falling as rain rather than as snow Groundwater Indirect Reduction in snowpack and extended periods of drought are likely to increase dependency on groundwater Source: http://frap.fire.ca.gov/data/assessment2010/pdfs/3.1water.pdf p. 140 Vulnerability to Drought (High) The historical and potential impacts of drought on property include crop loss, injury and death of livestock and pets, and damage to infrastructure and other buildings resulting from the secondary or cascading drought impacts such as land subsidence, soil erosion, and flash flooding. As a related drought impact, tree mortality has resulted in potentially vulnerable critical infrastructure property as these trees become more susceptible to falling with time and could affect properties in the county. For the following vulnerability categories crop losses, potential health issues related to drought, tree mortality, and other such issues tied to secondary and cascading impacts will be discussed. General Property Based on the USDA’s Risk Management Agency Crop Indemnity Reports, which were collected for the years 2015-2018, crop losses due to drought were reported in every year except 2017 across the county. Table 5-58 summarizes the agricultural losses experienced across the county communities. A total of $870,473 was indemnified for 11,169 acres of affected crops covering 30 policies, just in the last few years (since the last County hazard mitigation plan from 2014). Table 5-58 Risk Management Agency Crop Indemnity Reports, 2015-2018 Year Crop Month of Loss Name Policies Indemnified Net Determined Acres Indemnity Amount Loss Ratio 2015 Wheat March 1 22 $ 1,541 4.05% September 1 22 $ 1,541 4.05% Walnuts May 1 40 $ 15,582 1.86% April 1 32 $ 20,186 8.90% July 1 104 $ 36,851 3.14% Grapes October 1 14 $ 63,113 17.57% September 1 12 $ 37,250 13.81% May 1 12 $ 29,745 10.23% Barley April 1 331 $ 5,672 6.48% February 1 691 $ 17,188 1.69% March 1 84 $ 2,816 1.41% September 1 84 $ 2,816 1.41% January 3 4,561 $ 323,541 2.23% January 2 715 $ 47,569 2.11% December 1 671 $ 16,682 1.69% ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-164 Year Crop Month of Loss Name Policies Indemnified Net Determined Acres Indemnity Amount Loss Ratio April 1 29 $ 259 0.30% 2016 Walnuts August 1 32 $ 13,360 5.70% February 1 104 $ 43,307 4.14% Grapes June 1 8 $ 4,933 2.45% 2018 Barley November 3 2,513 $ 146,165 2.16% January 1 389 $ 9,424 4.58% January 4 698 $ 30,932 2.04% TOTAL 30 11,169 $ 870,473 Source: USDA RMA Crop Indemnity Reports, 2019 In addition to crop losses, tree mortality hazards from drought, which compose just over 13% of the county in area, are found to intersect with a total of 39,540 properties across the county, based on the property centroids defined for all the hazards’ parcel analyses. Refer to the Adverse Weather: High Wind and Tornados section for a summary of the analysis. People According to this California Department of Finance (DOF) the 2018 County population was 280,118 people. The County’s population is projected to continue to increase by 0.4 percent annually through 2023 (Caltrans 2018). This projected population growth would add additional strain to the surface and already depleted groundwater supplies. The historical and potential impacts of drought on populations include agricultural sector job loss, secondary economic losses to local businesses and public recreational resources, increased cost to local and state government for large-scale water acquisition and delivery, and water rationing and water wells running dry for individuals and families. As drought is often accompanied by prolonged periods of extreme heat, negative health impacts such as dehydration can also occur, where children and elderly are most susceptible. Air quality often declines in times of drought which can affect those with respiratory ailments. Social Vulnerability The areas of the county with the highest overall social vulnerability, based on the SoVI data presented and discussed in subsection 4.4.1, such as the City of Paso Robles and the City of San Luis Obispo are also located within groundwater basins identified by the State Department of Water Resources as potential priority basins due the depletion of groundwater resources. Both the City of Paso Robles and the City of San Luis Obispo have formed Groundwater Sustainability Agencies (GSA) to develop and implement of groundwater sustainability plans (GSP) to ensure sustainable management of the groundwater resources within their basin for current and future populations. Critical Facilities Drought impacts to critical facilities include water shortfalls for facility operations and critical functions, and potential structural destabilization and damage resulting from land subsidence. Refer to the section on Subsidence for more information. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-165 Economy Drought impacts to the local or regional economy can be difficult to quantify but can be extensive and long-lasting depending on the circumstances during, and after a severe drought event. If water resources are limited, effects would be more severe for industries that rely on large amounts of water and any prolonged drought would intensify these impacts. Sectors critical to the economy such as commerce, distribution, agriculture, tourism, related environmental resources, municipal and industrial water supply, key city assets, energy generation, and even socioeconomic aspects can be affected due to lack of, or even reduced quality of water resources. Drought directly impacts rangeland for livestock in the County as was witnessed during the 2014 drought which had a significant impact on the ranching and agriculture economy. Between 2010 and 2014, roughly 75 percent of the cattle in San Luis Obispo County were sold or taken out of state to escape the drought conditions the County had been experiencing (LA Times 2015). The heavy reliance upon groundwater to irrigate rangeland for livestock makes this sector of the local economy especially vulnerable to future drought events. Historic, Cultural, and Natural Resources The historical and potential impacts of drought on the natural environment are widespread throughout public and private lands within the County, including tree mortality, impacts to all flora and fauna, and destabilization (erosion, subsidence) of land along streams and rivers, and within watersheds. One of the core issues shaping the impact of drought in San Luis Obispo County and throughout California is water supply and demand. Several factors play into the issue including groundwater basins, surface water run-off, public and agricultural demand, and surface water storage watersheds. As such, an analysis was conducted through the 2010 Forest and Rangeland Assessment to identify threats and assets in order to select Priority Landscapes (PL) where water supply would benefit from forest management designed to protect or enhance water resources, the key effort which, in part, both defines and mitigates the severity of drought risk and vulnerabilities. Given that the extent of the drought hazard is, in part, determined by the extent of groundwater over- pumping in San Luis Obispo County, it should also be pointed out that such over-pumping is part of a broader context of water supply and demand trends with related impacts to agriculture and the secondary hazard impacts from land subsidence resulting from groundwater withdrawal. The Paso Robles Groundwater Basin has experienced serious declines over the years due to groundwater pumping with the largest water use sector being agricultural uses (Paso Robles GSA, 2018). Refer to the Subsidence section for more information on the impacts on groundwater withdrawal. Tree mortality was identified as an additional drought impact of significance to the County during the 2019 update. Tree mortality is a cascading impact which also affects (or worsens) other hazards such as wildfire, agricultural and biological hazards, and wind. In addition, drought-impacted trees become susceptible to diseases and insect infestations (bark beetle) further adding to the risk of tree mortality and related potential impacts. A die of blue oak trees which are considered some of the most drought-tolerant trees caused alarm throughout the County during the multiyear drought from 2012-2015. Researchers stated the reasoning behind the oak tree mortality was due to the roots of the trees were no longer able to reach the aquifers due to severe groundwater depletion (Weiser 2017). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-166 The location, extent, and probability of occurrence for tree mortality can be viewed as sub-set to the drought hazard (though tree mortality issues are also discussed under other hazards sections such as Agricultural Pest Infestation and Plant Disease; Wildfires; Adverse Weather/Wind). Those areas of the natural environment susceptible to drought comprise a larger area, since tree mortality is related to other sub-factors specific to the species impacted such as tree age and soil composition. Refer to the Adverse Weather: High Wind and Tornado section for analysis on tree mortality in the county. Future Development With the County’s population projected to continue to grow while climate change projections are showing an increased duration an intensity of drought events for the Central Coast region, it will be important for each new development application to be reviewed with existing and future water supplies in mind. Because future development encompasses all forms of property, buildings, infrastructure, critical facilities and all related populations and their functions, drought impacts to future development align with the historical and potential impacts to populations, property, natural environment, and critical facilities discussed (above). Risk Summary • Due to the widespread impacts it can have, drought is considered a High significance hazard. • There have been five multi-year droughts in the past 90 years. Most recent drought lasted from 2012 to 2017 and resulted in a declared state of emergency. • 15 Disaster Declarations due to drought have been made in the last 41 years. • 124 reports of impacts related to drought were made within San Luis Obispo between, 1990 and February 11, 2019. • Between 2015-2018 a total of $870,473 crop indemnity claims was paid due to crop losses for a total of 11,169 acres due to drought impacts. • Significant impacts associated with past multiyear droughts have included 75% of livestock to be sold or moved out of state (2012-2015); Oak trees thought to be drought resilient were no longer able to reach aquifers and began to die off. • Climate change projections show that extreme prolonged drought is likely to continue and will exacerbate existing water supply challenges. • Related Hazards: Extreme Heat, Wildfire, Subsidence, Agricultural Pest Infestation and Disease Table 5-59 Drought and Water Shortage Hazard Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Extensive Likely Critical High City of Arroyo Grande Significant Likely Limited Medium City of Atascadero Extensive Likely Limited Medium City of Grover Beach Extensive Likely Limited High City of Morro Bay Limited Occasional Negligible Low City of Paso Robles Extensive Likely Limited High City of Pismo Beach Extensive Likely Negligible Medium ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-167 Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance City of San Luis Obispo Extensive Likely Limited Medium Avila Beach CSD Extensive Likely Critical High Ground Squirrel Hollow CSD Limited Occasional Negligible Low Heritage Ranch CSD Extensive Highly Likely Critical High Los Osos CSD Significant Likely Limited Medium Nipomo CSD Significant Likely Limited High San Miguel CSD Extensive Likely Catastrophic High San Simeon CSD Significant Likely Limited Medium Templeton CSD Extensive Likely Limited High Cayucos Sanitary District Limited Occasional Negligible Low Port San Luis Harbor District Extensive Likely Limited Low San Luis Obispo FCWCD Extensive Likely Critical High South San Luis Obispo Sanitary District Significant Likely Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-168 5.3.10 Earthquakes, Faults, and Liquefaction Hazard/Problem Definition An earthquake is a sudden, rapid shaking of the ground caused by the breaking and shifting of rock beneath the earth's surface or along fault lines. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface move slowly over, under, and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free causing the ground to shake. Most earthquakes occur at the boundaries where the plates meet, commonly called faults; however, some earthquakes occur in the middle of plates. A fault is a fracture in the earth’s crust along which movement has occurred either suddenly during earthquakes or slowly during a process called creep. Cumulative displacement may be tens or even hundreds of miles if movement occurs over geologic time. However, individual episodes are generally small, usually less than several feet, and are commonly separated by tens, hundreds, or thousands of years. Damage associated with fault-related ground rupture is normally confined to a fairly narrow band along the trend of the fault. Structures are often not able to withstand fault rupture and utilities crossing faults are at risk of damage. Fault displacement involves forces so great that it is generally not feasible (structurally or economically) to design and build structures to accommodate this rapid displacement. Fault displacement can also occur in the form of barely perceptible movement called “fault creep.” Damage by fault creep is usually expressed by the rupture or bending of buildings, fences, railroads, streets, pipelines, curbs, and other linear features. Excellent examples of fault creep can be seen in the Carrizo Plain area of eastern San Luis Obispo County where gradual creep on the San Andreas fault has offset stream beds, roadways, and fence lines. In addition, there is also the potential for co-seismic creep, where movement on a fault is triggered by an earthquake on another nearby fault. Liquefaction occurs when ground shaking causes the mechanical properties of some fine grained, saturated soils to liquefy and act as a fluid (liquefaction). It is the result of a sudden loss of soil strength due to a rapid increase in soil pore water pressures caused by ground shaking. In order for liquefaction to occur, three general geotechnical characteristics should be present: 1) ground water should be present within the potentially liquefiable zone, 2) the potentially liquefiable zone should be granular and meet a specific range in grain-size distribution, and 3) the potentially liquefiable zone should be of low relative density. If those criteria are present and strong ground motion occurs, then those soils could liquefy, depending upon the intensity and duration of the strong ground motion. Liquefaction that produces surface effects generally occurs in the upper 40 to 50 feet of the soil column, although the phenomenon can occur deeper than 100 feet. The duration of ground shaking is also an important factor in causing liquefaction to occur. The larger the earthquake magnitude, and the longer the duration of strong ground shaking, the greater the potential there is for liquefaction to occur. Geographic Area USGS Quaternary earthquake fault zones were mapped to display the location of fault lines in and near the planning area, along with active and potentially active earthquake faults as determined at the local level. Figure 5-53 below displays these fault lines. Figure 5-54 is a zoomed in version of the faults underneath the county as well as offshore the coastal areas of the county. The county is overall covered by various fault lines and zones, running in a north-south fashion from the coast to the eastern slopes. All ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-169 active and potentially active faults are located to the east and south of the county, on or near the San Andreas Fault Zone, San Juan Fault Zone, Morales Fault, and La Panza Fault Zones. The Rinconada and East Huasna Fault Zones run towards the middle of the county, north-south, with the South Cuyama Fault Zone entering Santa Barbara county to the south of the planning area. The southwest and coastal areas of the county include several faults as well including the West Huasna, San Luis Range, Edna, Cambria, and Oceanic Fault Zones. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-170 Figure 5-53 Earthquake Fault Lines and Zones in the Planning Area PACIF IC OCEAN Waterwa ys Lakes --+--+ Railroads --Highway Freewa y c::J cities ---Active Potentiall y Active USGS Quaternary Fau lts Map compiled 2/2019 ; Morr intended fo r planning purposes only. Data Source : San Luis Obispo County, US Census T IGER Database , CA Open Data Portal , USGS ••• Monterey Gro 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-171 Figure 5-54 Offshore Earthquake Fault Lines and Zones in the Planning Area ••• MON TE R EY --- PACIFIC OCEAN Map compi led 512019 ; ur oses on ly. intended fo r pla:~1~guis Jbispo County, Dat a Source_ ~E R Data base, CA Open US Census T l GS LA FCO Dat a Portal , US , 0 10 ry Fau lts USGS Quaterna waterways Lakes __ Hig hway ~--Freeway I so Robles ~"-.. ,. ii)(,~ N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-172 Figure 5-55 is an earthquake shaking map of the county that is based on the 2% probability of occurrence in 50 years, based on analyses of these faults, soils, topography, groundwater, and the potential for earthquake shaking sufficiently strong to trigger landslide and liquefaction. It represents worst-case ground shaking and supports the conclusion that the San Luis Obispo County planning area is at risk to future damaging earthquake hazards, especially in the eastern portion of the County near the San Andreas Fault. The western portion of San Luis Obispo County could experience ground accelerations in the range of 0.3 g (30% g) to 0.4 g (40% g) in the next 50 years. The eastern portion of the County adjacent to the San Andreas Fault could experience ground accelerations of 0.5 g (50% g) to 0.7 g (70% g) in the next 50 years. The statistical variance in estimated ground acceleration could easily be plus or minus 50 percent of the estimated ground motion. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-173 Figure 5-55 Ground Shaking Potential from Spectral Acceleration the Planning Area – Probability of Shaking 2% in 50 Years ••• ---Waterways Lakes -+--+ Railroads Highway PACIFIC OCEAN Probability of Shaking 2% in 50 Yea rs 70 -80% g Spectral Ace lie ration @ 1 Sec Freq . 60 -70% g ---180-2153/o g 50 -60% g 160 -180% g 40 -50% g 140 -160% g 30 -40% g 120 -140% g 20 -30% g 100 -120% g 10 -20% g 90-100% g -5-10% g 80 -90% g Map compiled 2/2019 ; intended for planning purposes only . Data Source : San Luis Obispo County, US Census TIGER Database , CA Open Data Portal , California Geological Survey, USGS '"--, \ ,r \ '~1 -------------------------i--41 --------------------------------- ' I I I I I I 46 I I I •-----7 I I I I '-'-·~ '-L. I )_ _____ _ I i I I '----.. I 58 I I I I , _______ J ' I ' I ·------1 ' I ' I ' Tulare L----, 0 10 20 40 Miles ,., I I ' ! I i l I ____ J ___ .,.7 L-----, L_ ~entur.a N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-174 Description of the Major Faults in San Luis Obispo County The California Geological Survey (CGS) is charged with recording and mapping faults throughout California. The Alquist-Priolo Earthquake Fault Zoning (AP) Act was passed into law following the destructive February 9, 1971 6.6 San Fernando earthquake. The AP Act provides a mechanism for reducing losses from surface fault rupture on a statewide basis. The intent of the AP Act is to insure public safety by prohibiting the siting of most structures for human occupancy on or near active faults that constitute a potential hazard to structures from surface faulting or fault creep. Fault zoning is continually updated and reviewed by CGS and it is likely that other faults in addition to those currently listed by CGS will be added to the list in the future. The primary active faults identified by the AP Act in the County include the San Andreas, San Simeon-Hosgri, and Los Osos faults. A map of these earthquake fault zones within the County is available below. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-175 Figure 5-56 Earthquake Fault Zone Designations in San Luis Obispo County ••• 1 SanAntoilio PACIFIC OCEAN Waterwa ys Lakes --+-----+ Railroads Highway Freeway F,::,! Cities Hazard Designation Morr Estero Earthquake Fault Area {not Alquist-Priolo) Los Osos Alquist-Priolo Earthquake Fau lt Zone San Andreas Alquist-Priolo Earthquake Fault Zone -San Simeon Alquist-Priolo Earthquake Fault Zone Map compiled 2/2019 ; intended for planning purposes on ly. Data Source: San Luis Obispo County, US Census TIGER Database , CA Open Data Portal Monte rey 0 10 20 ---✓-, \ ( Kings Tul are ,,, ---------------··------------1 Poso (,-eek Kern Sa nta Barba ra -, i.:..._ ____ _ L_ Ve ntura I i 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-176 Table 5-60 lists the major faults that have been mapped by the CGS in San Luis Obispo County (some of which were briefly introduced in this section and mapped under Figure 5-53). The potential for fault rupture hazards along other faults listed in the table as inactive faults is generally considered to be low. However, given the few active or potentially active faults in the planning area, earthquake hazards should be considered when placing a structure near or over any suspected fault location. Table 5-60 Major Faults in San Luis Obispo County Fault Name Maximum Moment Magnitude Activity Earthquake Hazard Zone Cambria 6.25 Potentially Active Yes Casmalia 6.5 Potentially Active No East Huasna unknown Potentially active No San Simeon-Hosgri 7.3 Active Yes La Panza Fault 7.5 Potentially Active No Los Osos 6.8 Active Yes Nacimiento unknown Active No Rinconada 7.3 Potentially Active No San Andreas (1857 rupture) 7.8 Active Yes San Andreas (1906) 7.9 Active Yes San Andreas-Carrizo 7.2 Active Yes San Andreas-Cholame 6.9 Active Yes San Andreas–Parkfield Segment 6.7 Active Yes San Juan 7.0 Potentially Active No San Luis Range 7.0 Potentially Active No Shoreline 6.5 Under Study Under Study Source: SLO HMP 2014 Cambria Fault: The northwesterly trending Cambria fault is approximately 64 kilometers (37.77 miles) long, including an 8-kilometer (5 mile) projection across Estero Bay. The fault is shown to coming back onshore near Morro Bay, and converging with the Oceanic and West Huasna fault near San Luis Obispo. The Cambria fault is considered potentially active. The Safety Element of the San Luis Obispo County General Plan lists the maximum moment magnitude as 6.25 for the Cambria. East Huasna Fault: The East Husana fault zone trends north-northwest for a distance of about 70 kilometers (43.5 miles) from near Sisquoc in Santa Barbara County northward until it intersects with the South Cuyuma fault about 20 kilometers (12.4 miles) east of the city of San Luis Obispo. The fault is considered potentially active. La Panza Fault: The northwest trending La Panza fault has been mapped for 71 kilometers (44 miles) along the western base of the La Panza Range. The La Panza fault has been identified as a thrust or reverse fault. The La Panza fault is considered potentially active. The Safety Element of the San Luis Obispo County General Plan lists the maximum moment magnitude as 5.0 - 7.5 for the La Panza. Los Osos and Edna Fault Zones: The Los Osos fault zone has been mapped generally in an east/west orientation, along the northern flank of the Irish Hills. The western end of the onshore fault zone is located near the community of Los Osos, and the eastern end located near U.S. Highway 101. To the east of U.S. Highway 101, the fault may continue along the northeast flank of the Irish Hills as the Edna fault ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-177 zone. Assuming an overall length of 56 kilometers (35 miles), the Los Osos fault has the potential to generate an earthquake with about a magnitude 6.75. Also near this area are the Hosgri and Shoreline faults. Nacimiento Fault Zone: The Nacimiento fault zone has been mapped as a regional fault by many investigators, however it is not included as part of the data base of California faults by the California Geological Survey (CSG). While the fault is considered inactive, the Bryson earthquake of 1952 is sometimes assigned to the Nacimiento fault zone, which would make the fault seismically active. The Bryson earthquake, which occurred in a rural area of northern San Luis Obispo County, is poorly understood and may be attributed to movement on other faults such as the active San Simeon or potentially active Riconada fault zones. The faults that make up the Nacimiento fault zone enter the County in the vicinity of Nacimiento Lake. Faults, or portions of the faults, related to this system trend southwest near the city of Paso Robles, parallel Highway 101, pass through or near Templeton, through or near the city of Atascadero, through the area in and near Santa Margarita, and continues south. Given the fault's proximity to major population centers, structures, dams, transportation and pipeline routes, it could pose a serious threat to the County. Rinconada Fault Zone: The Rinconada fault zone has been mapped as a regional fault zone about 189 kilometers (117 miles) long located along the western margin of the La Panza Range. The Rinconada fault is inferred to be part of a zone of faults including the Jolon, San Marcos, Espinosa, and Reliz faults that extends from Monterey Bay southward to its juncture with the Nacimiento fault. The California Geologic Survey considers the Rinconada fault to be potentially active. The county’s Safety Element lists the maximum moment magnitude as 7.3 for the Rinconada. San Andreas Fault: The San Andreas is a historically active fault thought to be capable of an earthquake up to and above the 8.0 magnitude range and generally runs along the eastern county border. It enters the County near the Cholame area, passes through the Carrizo Plain, and exits the county near Maricopa. As it passes through the County, three relatively distinct portions of the fault have separate potentials for causing a damaging earthquake. The portion of the fault that runs from Monterey County into San Luis Obispo County to an area near Cholame has commonly been known as the Parkfield segment of the San Andreas fault system. That portion of the fault system is the one that has an approximate 5.6 – 6.0 magnitude earthquake from time to time. A segment of the system that runs from approximately the Cholame area to about the northern edge of the Carrizo Plain area has been commonly known as the Cholame segment. The portion running from the northern Carrizo Plain area and out of the County into Kern County has been commonly known as the Carrizo segment. It is believed that in 1857 a large (possible 7.8 or larger) earthquake occurred on the San Andreas fault that possibly originated in the Parkfield area and stretched along the fault to the area near San Bernardino. This is perhaps an illustration of the potential for the San Andreas to cause a very powerful earthquake and the need to be prepared. A major earthquake along any section of the San Andreas Fault could result in serious damage within San Luis Obispo County. An earthquake of 8.0 or greater magnitude would result in severe ground motion and could cause damage throughout the County. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-178 Small earthquakes do occur in the area of the San Andreas within the County from time to time, perhaps most frequently in the Parkfield and nearby areas. Generally, they are so small or in such isolated areas that they are not felt or are felt only very close by. San Simeon - Hosgri Fault Zone: The San Simeon-Hosgri fault system generally consists of two fault zones: the Hosgri fault zone represented by a series of faults that are mapped off the San Luis Obispo County coast; and the San Simeon fault zone, which appears to be associated with the -Hosgri, and comes onshore near the pier at San Simeon point. The San Simeon fault is considered to be active. The Hosgri fault zone has been interpreted to extend from the northern termination west of the southern San Simeon fault in the Cambria/Point Estero area to its southern termination offshore of Point Perdernales, which is south of the Santa Maria River, off of Santa Barbara County. The Safety Element of the San Luis Obispo County General Plan lists the maximum moment magnitude as 7.3 for the Hosgri-San Simeon. Shoreline Fault: In 2008, the Shoreline Fault was discovered off the coast in the area of the Diablo Canyon Power Plant which is owned and operated by Pacific Gas and Electric Company (PG&E). The initial study of the fault, using conservative assumptions about the total length of the fault zone, indicates that a potential magnitude 6.5 strike-slip earthquake is possible. Follow up investigations were performed by PG&E in 2009 and 2010 and more detailed studies are planned in order to refine the size and potential of the fault. (Report on the Analysis of the Shoreline Fault Zone, Central Coastal California, Report to the U.S. Nuclear Regulatory Commission, January 2011, PG&E). To address public concerns regarding the seismicity of the area surrounding Diablo Canyon, PG&E is proceeding with additional fault studies, which have and do include research along the Los Osos Valley and in the Irish Hills. The company will share the results with local jurisdictions in order to enhance their knowledge of the seismic characteristics of the region for their emergency planning and building standards requirements. Outside the scope of this plan, the County, other local agencies, and state agencies maintain emergency planning procedures related to Diablo Canyon that are regulated by FEMA and the Nuclear Regulatory Commission. Fault Rupture Hazard Potential by Area The following paragraphs briefly discuss the fault rupture hazard potential for the cities and several of the highly populated unincorporated areas of the County including Cambria, Cayucos, Nipomo, Oceano, the South Bay area, San Miguel, Santa Margarita, and Templeton. Note this section is intended to generally describe fault rupture hazard by area; however, it does not mean significant damages may not occur in other areas. Arroyo Grande: Mapped faults in the City of Arroyo Grande are the potentially active Wilmar Avenue fault and the inactive Pismo fault. The Wilmar Avenue fault is exposed in the sea cliff near Pismo Beach and the buried trace of the fault is inferred to strike northwest-southeast parallel and adjacent to U.S. Highway 101 beneath portions of Arroyo Grande. The potentially active fault presents a moderate potential fault rupture hazard to the City. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. Atascadero: Mapped faults in the vicinity of Atascadero are the potentially active Rinconada fault and the Nacimiento fault zones. The Rinconada fault and its western associated fault, the Jolon, is mapped trending northwest along the eastern City limits. The fault mostly lies east of the Salinas River and outside the City limits. Although there is evidence that indicates movement along the Rinconada fault, the fault lacks any geomorphic features to suggest the fault is active. Because the Rinconada fault is potentially ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-179 active, it presents a moderate fault rupture hazard to the City of Atascadero. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. The Nacimiento fault zone consists of a nearly 10-kilometer wide northwest trending, complex fault zone located in the Santa Lucia Range of southwest Atascadero. The Nacimiento fault zone is classified as inactive by CSG but is believed to be coincident with the location of the epicenter for historic earthquakes that suggest the fault is seismically active. Given the uncertainty of the Nacimiento fault’s activity, further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. Grover Beach: The only mapped fault near Grover Beach is the potentially active Wilmar Avenue fault. The Wilmar Avenue fault is exposed in the sea cliff near Pismo Beach and the buried trace of the fault is inferred to strike northwest-southeast generally along the alignment of U.S. Highway 101 past Grover Beach. The mapped location of the fault runs along a portion of the northern city limits for Grover Beach. The Wilmar Avenue fault is considered potentially active and presents a moderate fault rupture hazard to the City. Further studies to evaluate the activity of the fault are warranted, prior to placing structures near the mapped fault traces. Morro Bay: The only known mapped faults in the City of Morro Bay are the potentially active Cambria fault and possible splays of the active Los Osos fault system. The Cambria fault is mapped within the eastern limits of the City. The Cambria fault consists of a complex system of thrust faults located primarily in the hills northeast of Morro Bay. The potentially active fault presents a moderate fault rupture hazard to City developments in that area. The Los Osos fault is active but presents essentially no fault rupture hazard to the City as it is only mapped in undeveloped areas. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. Paso Robles: The only known mapped fault within the City of Paso Robles is the Rinconada fault. The potentially active Rinconada fault is mapped through southwestern Paso Robles and crosses Highway 101 just south of Spring Street. A trace of the fault is also identified as running up Spring Street, which corresponds to a line of hot springs that once existed in this area but have since been capped and buried. As a potentially active fault, the Rinconada presents a moderate fault rupture hazard to the City. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. The northern end of the potentially active La Panza fault is located about 20 kilometers (12.43 miles) southeast of Paso Robles, near the town of Creston. The northwest striking La Panza fault is about 75 kilometers (46.6 miles) long. The Huerhuero fault is a possible extension of the La Panza and is mapped trending northwest along Huerhuero Creek south of Highway 46 but is not within the current City limits. Pismo Beach: There are no mapped active or potentially active faults in Pismo Beach. The inactive Pismo fault presents a very low potential fault rupture hazard. As noted above, the nearby cities of Arroyo Grande and Grover Beach are transected by the Wilmar Avenue fault which is considered potentially active. Based on the USGS Quaternary Faults layer mapped on Figure 5-53, however, nearby faults systems like the San Luis Range and Edna Fault Zones exist. As such, significant ground shaking would be possible near Pismo Beach. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-180 City of San Luis Obispo: CSG has mapped the active Los Osos fault through a portion of the City, which strikes northwest-southeast along the southwestern margin of the Los Osos Valley. Field evaluations for the main strand of the Los Osos fault, found evidence of movement in the last 11,000 years. This evidence of recent activity resulted in the establishment of an Earthquake Fault Zone by CSG in 1989 under the Alquist-Priolo Fault Zoning Act. It should not be interpreted that the active portion of the main trace of the Los Osos Fault is limited only to the designated Earthquake Fault Zone. Rather, the limits of the established zone correspond to the limits of the available information provided in site specific studies that show evidence of recent fault activity in that area. The Los Osos fault presents a high to very high fault rupture hazard to City developments near and southwest of the Los Osos Valley Road area. Other faults that are near the borders of San Luis Obispo are the West Huasna, Oceanic, and Edna faults. These faults are considered to be potentially active and present a moderate fault rupture hazard to developments in their vicinity. Unincorporated Areas in San Luis Obispo County Cambria: Mapped faults in the vicinity of Cambria include the Cambria and Oceanic faults, and the offshore Hosgri fault. Although the offshore Hosgri fault is considered to be active and a likely source for future seismic events, it does not itself provide a fault rupture hazard to onshore facilities. The potentially active Cambria fault consists of a complex web of thrust faults that trend northwest along Highway 1 into the town of Cambria. In the vicinity of Cambria, the fault zone extends from the eastern portion of the town eastward for about two kilometers (1.24 miles). The potentially active Oceanic fault zone consists of a zone of northwest trending faults located about 8 kilometers (5 miles) northeast of Cambria. Because the faults are considered to be potentially active, they present a moderate fault rupture hazard to the town of Cambria. Further studies to evaluate the activity of the faults are warranted prior to placing structures near the mapped fault traces. Cayucos: Faults in the vicinity of Cayucos include the Cayucos, Cambria, and Oceanic fault zones. Geologic mapping recorded the buried trace of the northwest striking Cayucos fault beneath the town of Cayucos. The fault is considered to be inactive and therefore results in a low potential to serve as a fault rupture hazard. Although the CSG considers the Cayucos fault to be inactive, it is often undesirable to site structures over any fault as a result of non-uniform foundation support conditions and the potential for co-seismic movement that could result from earthquakes on other nearby faults. The northwest striking Oceanic fault zone is located about two kilometers (1.24 miles) northeast of Cayucos. The Cambria fault zone is mapped as going offshore north of Cayucos and returning to shore as a broad zone of faults passing through Cayucos. These faults are considered to be potentially active and therefore present a moderate fault rupture hazard. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. Nipomo: The faults in the Nipomo area include the Santa Maria River, Wilmar Avenue, Oceano and West Huasna faults. The buried trace of the Santa Maria River/Wilmar Avenue fault is inferred to parallel U.S. Highway 101 in the vicinity of Nipomo. The Oceano fault generally is trending northwest across the Nipomo Mesa and into the town of Oceano. The West Huasna fault is mapped along the eastern side of the valley. These faults generally have a subdued topographic expression and are considered to be potentially active by CSG. Review of the Oceano fault suggests that the fault is inactive. On the basis of that information, potentially active faults ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-181 present moderate fault rupture hazard in the Nipomo area. The inactive Oceano fault presents a very low potential as a fault rupture hazard. Although the Oceano fault is inactive, it is often undesirable to site structures over any fault as a result of non-uniform foundation support conditions and the potential for co-seismic movement that could result from earthquakes on other nearby faults. Further studies to evaluate the activity of the Wilmar Avenue and West Huasna faults are warranted, prior to placing structures near the mapped fault traces. Oceano: The only known mapped fault in the vicinity of Oceano is the Oceano fault. The buried trace of the potentially active Oceano fault is interpreted to strike northwest along the southwestern side of the Cienega Valley about 1,000 meters southwest of Oceano and goes offshore near the mouth of Arroyo Grande Creek. Although the fault is classified as potentially active by CSG, review of the Oceano fault suggests that the fault is inactive. The Oceano fault presents a very low fault rupture hazard to Oceano. Although the Oceano fault is likely inactive, it is often undesirable to site structures over any fault as a result of non-uniform foundation support conditions and the potential for co-seismic movement that could result from earthquakes on other nearby faults. South Bay: The South Bay area includes the communities of Los Osos, Cuesta by-the-Sea, Baywood Park, and the south Morro Bay area. Mapped faults in the South Bay area include the active Los Osos fault. As mapped the Los Osos fault consists of a several hundred-meter-wide zone of west-northwest striking lineaments and scarps located along the southern side of the Los Osos Valley. Portions of the Los Osos fault have been zoned active by CSG. The activity of this fault segment is unknown but is inferred to be at least potentially active or possibly active. The Los Osos fault and related branches present a moderate to very high fault rupture hazard to the area. Further studies to evaluate the location and activity of the fault are warranted, prior to placing structures near the mapped fault traces. San Miguel: The data reviewed does not indicate that there are mapped active or potentially active faults in San Miguel. Santa Margarita: The only mapped fault in the Santa Margarita area is the potentially active Rinconada fault. The fault trends northwest through the Santa Margarita area near Pozo Road, Trout Creek, and the Salinas River. Although there is evidence that indicates movement along the Rinconada fault, the fault lacks any geomorphic features to suggest the fault is active. Because the Rinconada fault is potentially active, it poses a moderate fault rupture hazard to this area. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. Templeton: The only mapped fault in the Templeton area is the western trace of the potentially active Rinconada fault system referred to as the Jolon fault. The fault trends northwest through the community just south of the junction of Highways 46 and 101. Although there is evidence that indicates movement along the Rinconada fault, the fault lacks any geomorphic features to suggest the fault is active. Because the Rinconada fault is potentially active, it poses a moderate fault rupture hazard to this area. Further studies to evaluate the activity of the faults are warranted, prior to placing structures near the mapped fault traces. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-182 Areas Susceptible to Effects of Liquefaction Figure 5-57 indicates mapping of liquefaction susceptibility for the County. Liquefaction is important to consider for planning purposes as it can lead to ground failure associated with moderate and large earthquakes and contribute to substantial building and infrastructure losses. Descriptions of specific liquefaction risks in the county and its jurisdictions are included below the figure. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-183 Figure 5-57 Liquefaction Susceptibility in San Luis Obispo County PACIFIC OCEAN Liquefaction Risk -High Potential Moderate Potential Low Potential \/1/aterways Lakes --+--+ Railroads --Highway ---Freeway c::Jcities [~-=-] Counties ••• Map compiled 2/2019: intended for planning purposes only. Data Source: San Lui s Obispo County, US Census TIGER Database , CA Open Data Portal Monterey 0 Tulare Wl!:t< Rm.I Kern ~ ch lJ:.. , ~ yoGra ~ Santa Barbara ---L I Ventura I I I 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-184 County of San Luis Obispo: Portions of coastal San Luis Obispo County are under laid by sediments that may be vulnerable to liquefaction. Developed areas having a higher potential for liquefaction are the coastal communities of Oceano, Avila, South Bay, Cayucos, and Cambria. Site-specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials and if they require mitigation for development. Arroyo Grande: The areas of Arroyo Grande that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by younger alluvium. The younger alluvium underlies most of the low-lying downtown areas south of Branch Street and along Grand Avenue. Site-specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. Atascadero: The areas of Atascadero that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by younger alluvium. Portions of the City in the low-lying areas adjacent to Atascadero Creek, Graves Creek, and the Salinas River are mapped as being underlain by younger alluvium. Site-specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. Grover Beach: The areas of Grover Beach that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by beach sand and young alluvium. High ground water levels can be expected near the Pacific Ocean and adjacent to Meadow Creek. Site specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. Morro Bay: The areas of Morro Bay that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by beach and sand dune deposits and younger alluvium. A majority of the City is underlain by these alluvial, estuarine, beach and sand dune deposits. High ground water levels can be expected in the Embarcadero area and other beach front areas. Flood plain areas along Chorro, Little Morro and Morro Creeks are also underlain by younger alluvium. Site-specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. Paso Robles: The areas of Paso Robles that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by younger alluvium. Portions of the City that are located on recent alluvium in the low-lying areas adjacent to the Salinas River (or its tributaries) appear to have the highest potential for liquefaction. Site specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. City of San Luis Obispo: The areas of the City of San Luis Obispo that have a high potential to be underlain by potentially liquefiable sediments are those areas underlain by younger alluvium. Most of the City of San Luis Obispo is underlain by alluvium. Site specific studies are needed to evaluate if a geologic unit actually contains potentially liquefiable materials, and if they require mitigation for development. Extent (Magnitude/Severity) For extent, the severity of an earthquake, or the amount of energy released during an earthquake is usually expressed in terms of intensity or magnitude as described further below. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-185 Intensity: Intensity represents the observed effects of groundshaking at any specified location and earthquake shaking decreases with distance from the earthquake epicenter. Intensity is an expression of the amount of shaking at any given location on the ground surface based on felt or observed effects. Seismic shaking is typically the greatest cause of losses to structures during earthquakes. Intensity is measured with the Modified Mercalli Intensity (MMI) scale. The intensity of ground shaking at a particular site or structure is a function of many factors including: 1) earthquake magnitude, 2) distance from the epicenter, 3) duration of strong ground motion, 4) local geologic conditions (soil type and topography), and 5) the fundamental period of the structure. A brief description of those factors is presented below. The Modified Mercalli Intensity scale is summarized in Table 5-61, along with the effects associated with the MMI scale. Damage typically occurs in MMI of scale VII or above. Earthquake Magnitude: Magnitude represents the amount of seismic energy released at the hypocenter of an earthquake. It is based on the amplitude of the earthquake waves recorded. Seismologists have developed several magnitude scales; one of the first was the Richter Scale, developed in 1932 by the late Dr. Charles F. Richter of the California Institute of Technology. The Richter scale is numeric and has a logarithmic relationship between scale factors, so that a difference of one scale number represents a tenfold increase in measured amplitude, which in turn corresponds to an approximate 31x energy release difference when compared to the next whole number value. The Moment Magnitude scale (Mw, or M), which is a measurement of energy released by the movement of a fault and is the modern method used by seismologists to measure earthquakes. Overall, as the amount of energy released by an earthquake increases, the potential for ground shaking impacts also increases. Distance from Epicenter: Earthquake energy generally dissipates (or attenuates) with distance from a fault. Over long distances, this loss of energy can be significant, resulting in a significant decrease in ground shaking with increased distance from the epicenter. Duration of Strong Shaking: The duration of the strong ground shaking constitutes a major role in determining the amount of structural damage and the potential for ground failure that can result from an earthquake. Larger magnitude earthquakes have longer durations than smaller earthquakes. Local Geologic Conditions: The geologic and soil conditions at a particular site have the potential to substantially increase the effects of ground shaking. The thickness, density, and consistency of the soil, as well as shallow ground water levels, have the potential to amplify the effects of ground shaking depending on the characteristics of the earthquake. In general, the presence of unconsolidated soils above the bedrock surface can amplify the ground shaking caused by an earthquake. Fundamental Periods: Every structure has its own fundamental period or natural vibration. If the vibration of ground shaking coincides with the natural vibration period of a structure, damage to the structure can be greatly increased. The extent of damage suffered during an earthquake can also depend on non-geologic factors. The type of building and its structural integrity will influence the severity of the damage suffered. Generally, small, well-constructed, one- and two-story wood and steel frame buildings have performed well in earthquakes because of their light weight and flexibility. Reinforced concrete structures will also usually perform well. Buildings constructed from non-flexible materials, such as unreinforced brick and concrete, hollow concrete block, clay tile, or adobe, are more vulnerable to earthquake damage. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-186 Effects of Ground Shaking: The primary effect of ground shaking is the damage or destruction of buildings, infrastructure, and possible injury or loss of life. Building damage can range from minor cracking of plaster to total collapse. Disruption of infrastructure facilities can include damage to utilities, pipelines, roads, and bridges. Ruptured gas and water lines can result in fire and produce scour/inundation damage, respectively, to structures, as can fire from other causes, such as electrical damages. Secondary effects can include geologic impacts such as co-seismic fault movement along nearby faults, seismically induced slope instability, liquefaction, lateral spreading, and other forms of ground failure and seismic response. These secondary effects were demonstrated in Oceano by the San Simeon 2003 earthquake. Table 5-61 Earthquake Magnitude and Intensity Measurements and Associated Characteristics Magnitude Mercalli Intensity Effects Frequency Less than 2.0 I Microearthquakes, not felt or rarely felt; recorded by seismographs. Continual 2.0-2.9 I to II Felt slightly by some people; damages to buildings. Over 1M per year 3.0-3.9 II to IV Often felt by people; rarely causes damage; shaking of indoor objects noticeable. Over 100,000 per year 4.0-4.9 IV to VI Noticeable shaking of indoor objects and rattling noises; felt by most people in the affected area; slightly felt outside; generally, no to minimal damage. 10K to 15K per year 5.0-5.9 VI to VIII Can cause damage of varying severity to poorly constructed buildings; at most, none to slight damage to all other buildings. Felt by everyone. 1K to 1,500 per year 6.0-6.9 VII to X Damage to a moderate number of well-built structures in populated areas; earthquake-resistant structures survive with slight to moderate damage; poorly designed structures receive moderate to severe damage; felt in wider areas; up to hundreds of miles/kilometers from the epicenter; strong to violent shaking in epicentral area. 100 to 150 per year 7.0-7.9 VIII< Causes damage to most buildings, some to partially or completely collapse or receive severe damage; well-designed structures are likely to receive damage; felt across great distances with major damage mostly limited to 250 km from epicenter. 10 to 20 per year 8.0-8.9 VIII< Major damage to buildings, structures likely to be destroyed; will cause moderate to heavy damage to sturdy or earthquake-resistant buildings; damaging in large areas; felt in extremely large regions. One per year 9.0 and Greater VIII< At or near total destruction - severe damage or collapse to all buildings; heavy damage and shaking extends to distant locations; permanent changes in ground topography. One per 10- 50 years Source: USGS ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-187 Past Occurrences Where earthquakes have struck before, they will strike again. The central California coast has a history of damaging earthquakes, primarily associated with the San Andreas fault. However, there have been a number of magnitude 5.0 to 6.5 earthquakes on other faults which have affected large portions of the Central Coast. Recent events include the December 2003 - 6.5 magnitude San Simeon Earthquake and the September 2004 - 6.0 magnitude Parkfield Earthquake. Historically active faults are generally thought to present the greatest risk for future movement and, therefore, have the greatest potential to result in fault rupture hazards. Active and potentially active faults in San Luis Obispo County are shown on map found on page 41 (Map 2 from the San Luis Obispo County Safety Element). The areas of San Luis Obispo County most susceptible to the effects of liquefaction are those areas underlain by young, poorly consolidated, saturated granular alluvial sediments. These soil conditions are most frequently found in areas underlain by recent river and flood plain deposits. The map found on page 43 indicates areas of low to high liquefaction potential based on the geologic units (Map 3 from the San Luis Obispo County Safety Element). Following are historic earthquakes that have affected San Luis Obispo County: 1830 San Luis Obispo Earthquake. The 1830 earthquake is noted in the annual report from the Mission and had an estimated magnitude of 5. The location of the event is poorly constrained and cannot be attributed to a specific fault source, but the earthquake reportedly occurred somewhere near San Luis Obispo. 1857 Fort Tejon Earthquake. The approximate 7.9 Fort Tejon earthquake of 1857 was one of the greatest earthquakes ever recorded in the United States. It left a surface rupture scar over 350 kilometers (210 miles) in length along the San Andreas Fault and a maximum surface offset of about 9 meters (30 feet). Yet, despite the immense scale of this quake, only two people were reported killed by the effects of the shock. The location of the epicenter is not known. As the name suggests, one idea is to locate it near the area of strongest reported shaking, Fort Tejon. However, because there is evidence that foreshocks to the 1857 earthquake may have occurred in the Parkfield area, it is located near the northwestern end of the surface rupture, just southeast of Parkfield, near Cholame, on a map produced by the Southern California Earthquake Data Center (http://www.data.scec.org/significant/forttejon1857.html). The fact that only two lives were lost was primarily due to the nature of the quake’s setting. California in 1857 was sparsely populated, especially in the regions of strongest shaking, and this fact, along with good fortune, kept the loss of life to a minimum. The effects of the quake were quite dramatic, even frightening. Were the Fort Tejon shock to happen today, the damage would easily run into billions of dollars, and the loss of life would likely be substantial, as the present-day communities of Wrightwood, Palmdale, Frazier Park, and Taft (among others) all lie upon or near the 1857 rupture area. 1906 San Francisco Earthquake. This earthquake has been studied in detail and the effects in San Luis Obispo County have been documented. Modified Mercalli intensity ratings ranged from III-IV in the inland and north coast portions of the County, and IV-V in the south coast areas. The higher intensities were felt in areas underlain by alluvial soil, while the lower intensities occurred in areas underlain by bedrock formations. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-188 1916 Avila Beach Earthquake. This magnitude 5.1 event occurred offshore of Avila Beach in San Luis Bay. The earthquake reportedly resulted in tumbling smokestacks of the Union Oil Refinery at Port San Luis, and a landslide that blocked the railroad tracks. The maximum intensity appears to be approximately VI, but the available descriptions of the shaking are somewhat limited. 1952 Arvin-Tehachapi Earthquake. This 7.7 magnitude earthquake occurred on the White Wolf fault, located south and west of Bakersfield. Throughout most of the San Luis Obispo County, ground shaking intensities of VI were felt. Intensities of IV-V were experienced in the northwest portion of the County, and magnitude VIII intensities were felt in the Cuyama area, in the southeast portion of the County. The higher intensities were likely due to closer proximity to the earthquake epicenter. 1952 Bryson Earthquake. This magnitude 6.2 earthquake likely occurred on the Nacimiento fault and resulted in intensity ratings of VI throughout most of the western portion of the County. Intensities of IV- V were experienced in the eastern portion of the County. Higher intensities were generally felt in the coastal valley areas that are underlain by alluvial soils. 1934, 1966 and 2004 Parkfield Earthquakes. These earthquakes were all three in the range of magnitude 6.0 and occurred on the San Andreas fault in or near the northeast corner of the County. Earthquake intensities generally conformed to anticipated characteristics for events of this size, with intense shaking (VII-VIII) being limited to a relatively small area near the epicenters of the quakes. Moderate shaking was experienced in most of the central and western parts of the County. A variation from the expected intensity characteristics was experienced in the La Panza area during the 1934 earthquake. La Panza is approximately 40 miles south of the fault rupture area, but experienced earthquake intensities of VII. 2003 San Simeon Earthquake. The San Simeon Earthquake struck at 11:15 a.m. on December 22, 2003. The magnitude 6.5 earthquake is attributed to having occurred near the San Simeon/Oceanic/Hosgri Fault system. The epicenter was approximately six miles from the community of San Simeon. In addition to significant property and other damages, two fatalities resulted from damages caused by the earthquake. The nearest affected city was Paso Robles. Perhaps not surprisingly, the issue of retrofitting unreinforced masonry buildings began to receive more attention as a result of this damaging earthquake. It was also reported that of the 53 unreinforced masonry buildings in the city, none of the 9 retrofitted buildings experienced major damages. However, unreinforced ones continue to prove highly dangerous across the county and the state, often partially or completely collapsing during earthquake events such as this one. 2014 Earthquake west of the San Simeon Fault, near Cambria. This was a rather weak seismic event of a 4.1 Magnitude about 14 kilometers south-southwest of San Simeon. It had a depth of 2.9 km and occurred on February 6 of 2014, beginning at approximately 7:42pm (UTC time). No damages were reported but the ground shaking was weakly felt on several communities including Cambria, Cayucos, Lake Nacimiento, Templeton, Morro Bay, Paso Robles, Atascadero, Los Osos, San Miguel, and Shandon. Earthquakes which have occurred outside yet felt in the County during the last century include events such as the 7.0 Lompoc earthquake in 1927, and the 7.7 Arvin-Tehachapi earthquake of 1952. Other more recent earthquakes, such as the 1983 - 6.7 Coalinga earthquake, 1989 - 7.1 Loma Prieta earthquake, 1992 - 7.5 Landers earthquake and the 1994 - 6.6 Northridge earthquake were felt in San Luis Obispo County, but there was no damage to structures from these. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-189 The map below displays the common areas damaged by earthquakes based on historic evidence dating back to the year 1800. The occurrences are color-coded by damaging shaking intensity across the state of California, and the county of San Luis Obispo is enclosed within a black circle. The figure shows that, per the Modified Mercalli Intensity scale noting occurrences equal to or greater than an intensity of 8, the county has experienced 1 to 3 earthquake events of this kind. Figure 5-58 Areas Damaged by Earthquakes from the Year 1800 to 2017 Source: California State Hazard Mitigation Plan, 2018; California Geologic Survey 0 50 I I I I I I I 100 Miles I 0 50 100 Kilometers ••• Minimum Number of Occurrences of Damaging Shaking Intensity (MMI >= VII) 8 I 7 6 5 1 4 I 3 I 2 1 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-190 Probability of Future Occurrences Likely - It is estimated that major earthquakes (ranging from a magnitude of 7 to 7.9) occur in California 1 out of every 10 years. However, strong earthquakes (from magnitudes 6 to 6.9) strike the state about once every two to three years. A strong earthquake can cause major damage depending on the epicenter’s location with regards to populated areas, and can lead to billions of dollars in disasters, deaths, injuries, and disruptions in services and communities’ way of life. Moderate earthquakes (around magnitudes of 5.5) can occur three to four times a year in the state. The San Simeon event in 2003 which affected Paso Robles caused 2 deaths, 47 injuries, and $263 million in damages. Per Figure 5-58 above, additionally, historical evidence shows that an earthquake of intensity 8 or greater is expected to occur 1 to 3 times every 200 hundred or so years. Climate Change Considerations While climate change is not expected to directly affect earthquake frequency or intensity; it could exacerbate indirect or secondary impacts of earthquakes. For example, climate change could increase the frequency and intensity of extreme precipitation events, in turn increasing the probability of landslides and liquefaction events during an earthquake if the earthquake coincided with a wet cycle. (Natural Resources Agency, 2018; California’s Fourth Climate Change Assessment, 2018). Vulnerability to Earthquake Earthquake loss estimation for the 2019 HMP update utilized FEMA’s Hazus-MH 4.0 natural hazard loss estimation software. Hazus is a GIS based, standardized, nationally applicable multi-hazard loss estimation methodology and software. Local, state and federal government officials use Hazus for preparedness, emergency response, and mitigation planning. A level 1 Hazus analysis was performed which estimates damage based on an inventory database compiled at a national level aggregated to Census Tracts. As with any model there are uncertainties and the results should be considered approximate for planning purposes. To evaluate potential losses associated with earthquake activity in the planning area, a Hazus 2,500-year probabilistic scenario was run for the county of San Luis Obispo. The 2,500-year scenario represents a worst-case level of shaking that considers multiple faults in the region. The methodology utilizes probabilistic seismic hazard contour maps developed by the U.S. Geological Survey (USGS) for the 2014 update of the National Seismic Hazard Maps that are included with HAZUS-MH. The USGS maps provide estimates of potential ground acceleration and spectral acceleration at periods of 0.3 second and 1.0 second, respectively. The 2,500-year return period analyzes ground shaking estimates from the various seismic sources in the area with a 2 percent probability of being exceeded in 50 years. The International Building Code uses this level of ground shaking for building design in seismic areas. Hazus estimates the number of people displaced, the number of buildings and facilities/infrastructure damaged, the number of casualties, and the damage to transportation systems and utilities. Results produced by Hazus are reported by at the census tract level. The figure below displays the census tracts within the county and which were analyzed in this scenario, color-coded by the amount of total losses each tract experienced. The map is followed by the Hazus results broken up in respective sections. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-191 Figure 5-59 Hazus Earthquake Analysis for San Luis Obispo County – Total Losses by Census Tracts (in Thousands of Dollars) ••• PACIFIC OCEAN Total Losses (in Thousands of Dollars) □ $21 .1s9 -$100,ooo D $100 ,001 -$200 .000 -$2 00 ,001 -$300,000 -$3 00 ,001 -$386,706 Map compiled 5/2019; -+-+ Railroads --Highway --Freeway Deities [~=-~7 Co unties intended for planning purposes only. Data Source: Sa n Lu is Obispo Cou nty, US Census T IGER Database , CA Open Data Portal, FEMA Hazus 4 .0 Monterey B 10 20 I ' I Kings l Tulare I I I "" ·~ ·~ '~ I '----- Santa Barbara 40 Mil es ' I I --------------------I--------------- Kern ·-- , __ N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-192 General Property (Earthquake) Unreinforced Masonry Building (URM)s: Unreinforced masonry building type structures consist of buildings made of unreinforced concrete and brick, hollow concrete blocks, clay tiles, and adobe. Buildings constructed of these materials are heavy and brittle, and typically provide little earthquake resistance. In small earthquakes, unreinforced buildings can crack, and in strong earthquakes, they have a tendency to collapse. These types of structures pose the greatest structural risk to life and safety of all general building types. Due to the public safety risks that are posed by unreinforced masonry buildings, the California legislature passed Senate Bill 547 (Government Code Section 8875 et seq.). This legislation went into effect January 1, 1987, and required all cities and counties located in Seismic Zone 4, which includes San Luis Obispo County, to conduct an inventory of potentially hazardous structures, including unreinforced masonry buildings. To comply with the requirements of SB 547, the County of San Luis Obispo adopted the Uniform Code for Building Conservation as part of Title 19 (Building and Construction Ordinance) of the County Code. Surveys that were conducted to identify potentially unsafe unreinforced masonry buildings identified about 80 structures that required modifications to meet specified earthquake resistance structural standards. Identified structures that require seismic retrofit are generally located in various areas, mostly urban. The County’s ordinance implementing SB 547 requires the owners of identified unreinforced buildings to demolish the structures or complete modifications, depending upon the building’s use and number of occupants. As of June 2019, only four structures remain on the URM registry. These buildings have had URM parcel tags applied and include the following: • Sims Hotel – San Miguel • Templeton Forest – Templeton • Shandon Valley Inn – Shandon • Oceano Bar/Critter Korner – Oceano Fault Rupture Risk: The most significant damage from fault rupture is anticipated in areas that are designated as such through the Alquist Priolo Fault Zoning Act. While future development is restricted in these areas the following table summarizes a GIS analysis of parcel center points that intersect the AP Fault Zones. Table 5-62 Parcels at Risk to Fault Rupture - Alquist-Priolo Zones Jurisdiction Seismic Designation Property Type Property Count Improved Value CITY OF SAN LUIS OBISPO Los Osos Alquist-Priolo Residential 28 $9,541,741 Residential: Other 2 $693,134 TOTAL 30 $10,234,875 Unincorporated Estero Fault Area Agricultural 1 $849,393 Government/Utilities 1 -- Residential 7 $1,789,318 Mobile/Manufactured Homes 4 $1,197,306 Vacant 2 $78,190 Los Osos Alquist-Priolo Government/Utilities 1 -- Other/Exempt/Misc. 1 -- ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-193 Jurisdiction Seismic Designation Property Type Property Count Improved Value Residential 29 $18,800,436 San Andreas Alquist-Priolo Agricultural 2 $8,185 Government/Utilities 4 -- Other/Exempt/Misc. 1 -- Residential 4 $622,397 Vacant 6 $809,245 San Simeon Alquist-Priolo Government/Utilities 1 -- Other/Exempt/Misc. 1 -- Residential 1 $8,171 TOTAL 66 $24,162,641 GRAND TOTAL 96 $34,397,516 Source: County of San Luis Obispo Planning and Building; Wood Plc Parcel Analysis Non-structural items and building components can also influence the amount of damage that buildings suffer during an earthquake. Unreinforced parapets, chimneys, facades, signs, and building appendages can all be shaken loose, creating a serious risk to life and property. Hazus Results: There are an estimated 109 thousand buildings in the region with a total building replacement value (excluding contents) of $32 billion. In terms of building construction types found in the region, wood frame construction makes up 83% of the building inventory. The building losses are broken into two categories: direct building losses and business interruption losses. The direct building losses are the estimated costs to repair or replace the damage caused to the building and its contents. The business interruption losses are the losses associated with inability to operate a business because of the damage sustained during the earthquake. Business interruption losses also include the temporary living expenses for those people displaced from their homes because of the earthquake. The total building-related losses were $5.9 billion. By far, the largest loss was sustained by the residential occupancies which made up over 56% of the total loss. The figure and table below provide a summary of the losses associated with the building damage. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-194 Figure 5-60 Earthquake Losses by Loss Type and Occupancy Type (in Millions of Dollars) Source: Hazus-MH 4.0 Figure 5-61 Hazus 2,500 Probabilistic Earthquake Scenario Structure Damage by Occupancy Type Source: Hazus-MH 4.0 Hazus estimates that about 39,034 buildings will be at least moderately damaged. This is over 36% of the total number of buildings in the region. There are an estimated 5,298 buildings that will be damaged beyond repair. Table 5-63 summarizes the expected damage by property occupancy type in more detail, whereas Table 5-64 contains the results of the expected building damage by building material type. Earthq uake Losses by Loss Type ($ millions ) 40 ,000 35,000 30,000 25 ,000 20,000 15,000 10,000 5,000 0 ••• ~-s-0 ;_.(ii 'I"<:$ .n._ />~ ~., c.,a' ■ Capitil-Related 3% ■ Content 20% ■ Inventory 1% ■ Non_Structural 5 1% ■ Relocatton 6% Rent al 3% ■ Structura l 12% ■ Wage 4% Total: 10 0% -o~ .. ~ r!P"" .~ <t.,o-s ,,.., r:P Earthqua ke Losses by Occupa ncy Type ($ milli ons ) ~ ~ ~ ~ - - --■1 tll ■ i.C" ~--~ 0~0' ~;;;. -~"' ?$"' ,::,li' '<--" 4'~ .... ,~IS ,i/" <,_'Ii ~ ■ ■ ■ ■ Single Fa mily Other Res idential Com mercia l lnclu st ri a l Others ■ Complete ■ Extensi ve Moderate ■ Sli ght Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-195 Table 5-63 Expected Building Damage by Occupancy Class Source: Hazus-MH 4.0 Table 5-64 Expected Building Damage by Building Material (All Design Levels) Source: Hazus-MH 4.0 Hazus also estimates the amount of debris that will be generated by the earthquake event analyzed. The model subdivides the debris into two general categories: a) Brick/Wood, and b) Reinforced Concrete/Steel. This distinction is made because of the different types of material handling equipment required to handle the debris. The model estimates that a total of 1.35 million tons of debris will be generated. Of that total amount, Brick/Wood comprises 36% of the debris, while the remainder would be Reinforced Concrete/Steel. If the debris tonnage was converted to estimates of truckloads required to remove it, debris generated would convert to about 54,040 truckloads, with each truckload carrying 25 tons. Figure 5-62 summarizes the debris generation and material type for this earthquake event. . - Agr icu lture Comm ercial Education Government Industrial Other Res idential Rel igion Sing le Family Total Wood Stee l Concrete Precast RM URM MH Total •Note : ••• R M URM M H None Count (%) 95 0 .32 820 2 .78 4 3 0.15 24 0 .08 206 0 .70 1 ,390 4 .7 1 86 0 .29 26 ,867 90.98 29 ,531 None Count (%) 28 ,144 95 .30 160 0 .54 275 0.93 180 0 .61 665 2 .25 39 0 .1 3 67 0.23 29 ,531 Rein forced Masonry Unreinforced Masonry Manufactured Hous ing Slight Count (%) 133 0 .32 1,114 2 .72 52 0 .13 30 0 .07 306 0.75 2 ,224 5.42 110 0 .27 37 ,053 90.32 41 ,024 Sl ig ht Count (%) 38978 95 .01 244 0 .59 396 0.97 270 0 .66 570 1 .39 72 0 .17 495 1 .21 41 ,024 Moderate Extensive Complete Count (%) Count (%) Count (%) 142 0 .56 79 0 .96 6 1 1.16 1 ,635 6.42 1 ,102 13 .35 660 12 .46 52 0 .20 27 0 .32 14 0.27 40 0 .16 29 0 .36 19 0 .36 509 2 .00 380 4 .60 271 5.11 3 ,550 13 .93 4 ,429 53.65 3 ,620 68.32 128 0 .50 84 1 .02 52 0 .97 19 ,426 76.23 2 ,124 25.73 602 11 .37 25,482 8 ,254 5 ,298 Moderate Extensive Complete Count (%) Count (%) Count (%) 20 ,42 7 80 .1 6 2 ,238 27.12 685 12 .9 3 586 2 .30 550 6.67 343 6.46 466 1.83 327 3 .97 205 3.87 512 2 .01 350 4 .25 207 3 .90 855 3 .36 540 6 .54 232 4 .37 139 0 .55 117 1 .42 138 2 .6 0 2 ,497 9 .80 4 ,13 1 5004 3 ,490 65 .87 25 ,482 8,254 5,298 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-196 Figure 5-62 Debris Generation in Millions of Tons and by Material Type Source: Hazus-MH 4.0 People (Earthquake) Shelter Requirement: Hazus estimates the number of households that are expected to be displaced from their homes due to the earthquake and the number of displaced people that will require accommodations in temporary public shelters. The model estimates 3,063 households to be displaced due to the earthquake. Of these, 2,146 people (out of a total population of 269,637) will seek temporary shelter in public shelters. Casualties: Ground movement during an earthquake is seldom the direct cause of death or injury. Most earthquake-related injuries result from collapsing walls, flying glass, and falling objects as a result of the ground shaking, or people trying to move more than a few feet during the shaking. Hazus estimates the number of people that will be injured and killed by the earthquake. The casualties are broken down into four severity levels that describe the extent of the injuries. The levels are described as follows: • Severity Level 1: Injuries will require medical attention, but hospitalization is not needed. • Severity Level 2: Injuries will require hospitalization but are not considered life-threatening. • Severity Level 3: Injuries will require hospitalization and can become life threatening if not promptly treated. • Severity Level 4: Victims are killed by the earthquake. The casualty estimates are provided for three times of day: 2:00 AM, 2:00 PM and 5:00 PM. These times represent the periods of the day that different sectors of the community are at their peak occupancy loads. The 2:00 AM estimate considers that the residential occupancy load is at its maximum. The 2:00 PM estimate considers that the educational, commercial and industrial sector loads are at their maximum. The 5:00 PM represents peak commute time. These estimates of casualties are broken down in Table 5-65. Social Vulnerability Earthquake is a high significance hazard across the county due to past event history as well as the prominent presence of faults (including portions of active and potentially active faults on the eastern slopes). Because of this, the entire county’s population is exposed in some way to this hazard. Based on 0.2 0.4 0.6 0.8 Brick/ Wood Reinforced Concrete/Steel 0.49 0.86 ••• 1.2 1.4 Total Debris 1.35 ■ Total Debris II Total Debris Wood ■ Total Debris Steel Truck Load 54 ,040 (@25 tons/truck ) Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-197 the Social Vulnerability Index (SoVI) data presented and discussed in subsection 4.4.1, some of the most socially vulnerable areas of the County are also exposed to earthquake hazards. This includes: Paso Robles, where the Rinconada and San Andreas fault zone are in the vicinity; Morro Bay, crossed by parts of the Cambria fault zone; the city of San Luis Obispo, crossed by the Edna and Cambria fault zones; Grover Beach and Oceano area, where San Luis Range fault system fault zones are present; and Nipomo, which is in proximity to the San Luis Range fault system, West Huasna fault zone, and smaller zones such as the Garey faults. Populations most vulnerable to earthquake and liquefaction activity would be those that rely on specific services or electrical power, which may not be available during or after a quake, or those which are homeless, would have a difficult time evacuating due to age or disability, cannot communicate easily due to speaking English less than well, for example. Table 5-65 Hazus Earthquake Casualty Estimates from San Luis Obispo County Source: Hazus-MH 4.0 Level 1 Level 2 Level J Leve l 4 2 AM Commercial 23 7 1 2 Commuting 0 0 0 a Educationa l 0 0 0 0 Hotels 0 0 0 0 lndusbial 28 8 1 2 Other-Res idential 600 146 14 26 Sing le Famil y 299 45 3 4 iTotal ! 950 206 20 35 2PM Commercial 1,3 12 380 62 121 Commuting 2 2 4 1 Educationa l 505 146 24 47 Hotels 0 0 0 0 lndusbial 206 59 9 18 other-Res idential 129 31 3 6 Sing le Farrul y 64 10 1 1 iTotal I 2,217 628 103 194 5PM Commercial 930 269 44 85 Commuting 31 40 68 13 Educationa l 113 32 5 10 Hotels 0 0 0 0 lndusbial 129 37 6 11 other-Res idential 220 54 5 10 Sing le Family 116 18 1 2 iTotal J 1,538 449 130 131 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-198 Critical Facilities and Infrastructure (Earthquake) Critical Facility Inventory: Hazus breaks critical facilities into two groups: essential facilities and high potential loss (HPL) facilities. Essential facilities include hospitals, medical clinics, schools, fire stations, police stations and emergency operations facilities. High potential loss facilities include dams, levees, military installations, nuclear power plants and hazardous material sites. Essential Facility Damage: There are 7 hospitals in the region with a total bed capacity of 1,484 beds. There are 105 schools, 19 fire stations, 14 police stations and 1 emergency operation facility. The inventory also includes 28 hazardous material sites, 0 military installations and 1 nuclear power plant. On the day of the earthquake, the model estimates that only 713 hospital beds (48%) are available for use by patients already in the hospital and those injured by the earthquake. After one week, 90% of the beds will be back in service. By 30 days, 99% will be operational. The essential facility inventory and expected damages from the earthquake event are provided in Table 5-66. Transportation Systems Inventory: Within Hazus, the lifeline inventory is divided between transportation and utility lifeline systems. There are 7 transportation systems that include highways, railways, light rail, bus, ports, ferry and airports. There are 6 utility systems that include potable water, wastewater, natural gas, crude & refined oil, electric power and communications. The transportation systems inventory and expected damages from the earthquake, in terms of number of structures and locations affected, are provided in Table 5-67, while losses in millions of dollars are summarized in Table 5-68. The total value of the lifeline inventory is over $5.77 billion. This inventory includes over 812 kilometers (504.5 miles) of highways, 357 bridges, and 20,068 kilometers (12,469.6 miles) of pipes. Utility Lifeline Systems Inventory: The replacement value of the transportation and utility lifeline systems combined is estimated to be $4.4 billion and $1.3 billion, respectively. The expected utility system facility damages in terms of total structures or systems affected, along with the inventory of this dataset, are summarized in Table 5-69. Economic losses in millions of dollars are found in Table 5-70. Site specific expected utility system pipeline damages (including their inventory) are included in Table 5-71, while the potable water and electric power system performance limitations, damages, and inventory will be in Table 5-72. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-199 Table 5-66 Essential Facility Inventory and Expected Damage Source: Hazus-MH 4.0 # Facilities Class ification Total At Least Moderate Complete With Functionality Damage> 50 % Damage> 50 % > 50 % on day 1 Hospitals 7 0 0 0 I Schools 105 0 0 0 I - EOCs 1 0 0 0 Pol iceStations 14 0 0 0 FireStations 19 0 0 0 ..._ ~ ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-200 Table 5-67 Transportation Systems Inventory and Expected Damage by Number of Locations Source: Hazus-MH 4.0 Number of Locations_ System Component Locations / With at Lea.st With Complete With Funct io nalitv > 50 % Segments Moel . Damage Damage After Day 1 After Day 7 Hig hway Segments 222 0 0 222 222 Bridges 357 54 8 305 317 T unnels 0 0 0 0 0 Ra ilways Segments 15 0 0 15 15 Bridges 8 0 0 8 8 T unnels 0 0 0 0 0 Facilit ies 3 3 a 1 3 Ught Rail Segments 0 0 0 0 0 Bridges 0 0 0 0 0 T unnels 0 0 0 0 0 Facilit ies 0 0 0 0 0 Bus Facil it ies 11 11 D 7 11 Ferry Facilities 0 0 a 0 0 Port Facil it ies 0 0 D 0 0 Air port Facil it ies 2 2 0 1 2 Runways 4 0 0 4 4 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-201 Table 5-68 Transportation System Economic Losses in Millions of Dollars Source: Hazus-MH 4.0 System Component I nventory Value Econom ic Loss Loss Rat io (%) Highway Segments 3 ,7 11.93 $0.00 000 Bridges 425.58 $57 .82 13.59 Tunne ls 0 .00 $0.00 0 .00 Subtota l 4,138 57.80 Rai lways Segments 104 .32 $0.00 0 .00 Bridges 0.85 $0.08 8.85 Tunne ls 0.00 $0.00 000 Facil ities 7 .99 $3.6 6 45.82 Subtotal 113 3 .70 Light Rai l Segments 0.00 $0.00 000 Bridges 0.00 $0.00 0 .00 Tunne ls 0 .00 $0.00 0 00 Facil ities 0.00 $0.00 0 .00 Subtotal 0 0.00 Bus Facil ities 14 .1 5 $6.47 45.76 Subtota l 14 6 .50 Ferry Facil ities 0 .00 $0.00 000 Subtota l 0 0 .00 Port Facil ities 0 .00 $0.00 000 Subtota l 0 0.00 A irport Facil ities 2 1.30 $9.92 46.56 Runways 151.86 $0.00 0.00 Su btotal 173 9.90 Total 4 ,438.00 78.00 - ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-202 Table 5-69 Expected Utility System Facility Inventory and Damages Source: Hazus-MH 4.0 , # Lo ca t ions / Re placem en t va lu e Syste m Com ponent Seg ments (m i l lions of dol lars) Pota ble Wa ter D istributio n Li nes NA 2 0 0 .70 Fa ciliti.es 1 3 9 .30 Pip el ines 0 0 .0 0 [Subtotal I ?.40~00 Wa ste Water Dfstribution Li nes NA 120 .40 Fa ci litfes 8 628 .70 Pipel in es 0 0 .00 [Subtotal I 749 .10 Natura l G as D istribution Li nes NA 80.30 Fa cfli ttes 0 0 .00 Pipel in es 0 0.00 [subtotal I 80 .30 Oi l Syste ms Fa ci littes 2 0.20 Pipel ines 0 0 .0 0 [s ubtotal I 0.20 Electrical Po w e r Faci lities 2 259 .6 0 [s ubtotal I 259 .60 Comm unication Fa ci lit ie s 34 4 .0 0 lSubtotal l 4 .00 ifotal I 1,33 3.20 ~ # of Locations System Total# With at Least With Comp lete w ith Functionality> 50 % Moderate Damage Damage After Day 1 After Day 7 Potabl e Water 1 1 0 0 1 Was t e Water 8 8 0 0 6 Natural Gas 0 0 0 0 0 Oil Systems 2 2 0 0 0 Electri cal Power 2 2 0 0 2 Communication 34 34 0 0 34 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-203 Table 5-70 Utility System Economic Losses in Millions of Dollars Source: Hazus-MH 4.0 Table 5-71 Expected Utility System Pipeline Damage (Site Specific) Source: Hazus-MH 4.0 System Component In v entory Value Economic Loss Loss Rati o (%) Pota ble Water Pipe lines 0 .0 0 $0.00 0.0 0 Fac ilities 39.30 $'16.47 4 1 .92 Distrib ut ion Li nes 20 0.70 $24 .'IO ·12 .0 1 ~ lSubtotal J 239 .98 $40 .58 Waste Water Pipe lines 0.0 0 $0.00 0 .00 Fac ilities 6 28.70 $233.58 3 7 .15 Distrib ut ion Li nes '120.40 $'17.28 '14 .35 (Subtotal I 749 .11 $250 ,85 Natura l Gas Pipe lines 0.0 0 $0.00 0 .00 Fac ilit ies 0.0 0 $0.0 0 0 .00 Dis trib utio n Li nes 80.30 $4.95 6.H ----- !Subtotal I 80.27 $4.95 O il Systems Pipe lines 0 .00 $0.00 0 .00 Fa cilfties 0.20 $0.08 32 .58 (Subtota l 7 0 .24 $0.08 -- El ectrical Power Fa cilities 259.6 0 $95.82 36 .9 1 ~ubtotal ~ 259 .60 $95 .82 Communication Fac ilities 4.0 0 $'1.53 38.'18 (Subtotal 7 4 .0 1 $1.53 (l"otal I I 1,333 .22 $393 .8 1 Syst em To t al Pi pel i nes Nu mbe r of Nu mber of Le n gth (kms) Leak s B r eak s I Potab l e Wate r 10,034 5357 1339 ----I Waste Wat er 6 ,02 1 3839 960 Natu ral Gas 4 ,014 11 0: I 275 I --7 -I O i l 0 I ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-204 Table 5-72 Expected potable Water and Electric Power System Performance Source: Hazus-MH 4.0 Diablo Canyon Power Plant: Located just north of Avila Beach this nuclear power plant was designed in the late 60’s and the first unit was put in service in 1985. Equipped with extensive seismic monitoring and safety systems, the plant is designed to shut down promptly in the event of significant ground motion. The HMPC noted that the Diablo Canyon Power Plant has been determined to withstand earthquake shaking, although the powerlines from the plant are still a concern. Diablo Canyon was originally designed to withstand a 6.75 magnitude earthquake. However, before its completion it was upgraded to withstand a 7.5 magnitude quake. This action was required based on the discovery of the Hosgri Fault located just off shore of the plant’s location. Bridges: The County of San Luis Obispo 2014 Bridge Maintenance Program report indicates 10 bridges due for replacement or rehabilitation; three bridges that are slated for seismic retrofits include: • Avila Beach Drive over San Luis Obispo Creek • South Bay Blvd Bridge over Los Osos Creek • Lopez Drive Bridge over Lopez Lake The document also notes procedures for post-earthquake bridge inspections. During the planning process the HMPC noted the following additional critical facilities and infrastructure that could be of concern in an earthquake event: the transcontinental fiber optic line as well as microwave communication site on mountain tops; State Water Project pipelines and the high-pressure gas and petroleum pipelines to Kern County that cross the San Andreas fault. In addition, a GIS overlay analysis was performed on the seismic designation hazard areas across the county with a combination of the county-provided critical facilities and the Homeland Infrastructure Foundation-Level Data, or HIFLD layers. The purpose was to find which critical facilities are found at risk of these seismic designation zones (Alquist-Priolo fault areas). The only critical facilities found at risk within the Los Osos Alquist-Priolo hazard area were two microwave service towers in the unincorporated area of the county. Economy (Earthquake) Hazus estimates the long-term economic impacts to the region. The model quantifies this information in terms of income and employment changes within the region. The total economic loss estimated for the earthquake is $6.3 B, which includes building and lifeline related losses based on the region's available inventory. An estimated 16% of losses computed by Hazus were related to the business interruption of the region. Since the building losses are broken into two categories (of direct building losses compared to business interruption losses), building related losses, which summarize estimates costs to fix or replace structures r Tota l # of Number of Households without Serv ice Househol ds At Day 1 At Day 3 At Day 7 At Day 30 At Day 90 Potable Water I 63 ,709 61 ,931 58 ,085 27 ,09 1 a I 102 ,0 16 49 ,542 1 Electric Power 76 ,869 21 ,771 4 ,580 102 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-205 and damages to properties and their contents are discussed in more detail in the General Property section of this section. However, business interruption losses are summarized herein. They included the temporary living expenses for people displaced from their homes because of the earthquake event. These business-related economic losses are included in Table 5-73 below. Table 5-73 Business-Related Economic Loss Estimates in Millions of Dollars Source: Hazus-MH 4.0 Historic, Cultural, and Natural Resources (Earthquake) Earthquake effects on the environment, natural resources, and historic and cultural assets could be very destructive depending on the type of seismic activity experienced and secondary/cascading effects from an event (e.g. wildfire). The biggest impact would likely be on older properties such as wooden or masonry buildings, though reinforced masonry structures would be much more resilient during earthquakes. No historic properties or structures were found within Alquist-Priolo seismic hazard designation areas. Future Development (Earthquake) Future development in the county is not anticipated to significantly affect vulnerability to earthquakes when designed according to modern building codes. However future development will result in a slight increase in exposure of the population, building stock, and related infrastructure to earthquakes. A GIS overlay analysis of building construction permits for residential and commercial properties was additionally performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties may be constructed, or may have upgrades completed, in Alquist-Priolo seismic designation hazard areas (Table 5-74). Category Area Single I Other Total l Family Residential Commercial Industrial Others Income Losses I Wa ge 0 00 24 .71 169 .04 5.78 9.02 208.55 I Capita l-Re lated 0 .00 10.55 149 .11 3.4 1 2 .53 165 .60 I Renta l 47 .34 53.44 68 .54 2 .07 4 .81 176 .2 0 I Relocation 170.34 51.86 109 .6 7 11.46 36.75 380.08 I ~ubtotal l 217 .68 140.56 496 .36 22.72 53 .11 930 .43 I Capital Stock Losses I Struct ura l 24 5.85 136 .31 220.08 50.75 63.74 716 .72 I --I Non St ruc t ural 1 ,330 77 627 .13 7 12 .88 198.13 159.06 3 ,027 .96 Content 477.10 148 .68 344 .86 128.45 85 .22 1,184 .30 I -I Inve ntory 0 .00 0.00 8.36 1 9 .80 3 .14 3 1.30 r Sub.total_____J 2 ,053.72 912 .11 1,286 .17 397.12 311 .16 4 ,960 .29 Total l 2 ,27 1.40 I 1,052 .68 I 1,782 .53 I 419.84 I 364.26 j 5 ,890.71 J ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-206 Table 5-74 Business Permits Submitted in Alquist-Priolo Seismic Designation Areas from 2014-2019 Seismic Hazard Designation Work Class Case Type Work Class Type Total Estero Fault Area New Structure PMTC - Commercial Permit 1 Los Osos Alquist-Priolo PMTR - Residential Permit 2 San Andreas Alquist-Priolo 1 TOTAL 4 Source: San Luis Obispo County Planning & Building Department, Wood GIS analysis Vulnerability to Liquefaction When liquefaction of the soil does occur, buildings and other objects on the ground surface may tilt or sink, and lightweight buried structures (such as pipelines) may float toward the ground surface. Liquefied soil may be unable to support its own weight or that of structures, which could result in loss of foundation bearing or differential settlement. Liquefaction may also result in the development of cracks in the ground surface followed by the emergence of a sand/water mixture, typically referred to as a sand-boil. In areas underlain by thick deposits of saturated, loose granular sediment (such as alluvial valleys or beaches), subsidence as much as several feet may result. Based on parcel and liquefaction risk overlay analysis, the following sections summarize how this hazard risk affects the county of San Luis Obispo. General Property (Liquefaction) Liquefaction activity, particularly that occurring along the coast of the County could have devastating effects in terms of property damage to properties and resources. During the 2019 update of this plan, a GIS analysis of improved property exposure to liquefaction risk areas was performed. GIS analysis indicates approximately over $10 billion in improved values of parcels found within moderate liquefaction risk areas, while $735 million in improved parcel values are found within high liquefaction risk zones. About $104 billion of that value is within unincorporated county areas, with over $3 billion from the moderate liquefaction risk areas and over $197 million from the high liquefaction risk zones. The table below summarizes the improved values for both moderate and high liquefaction risk areas based on hazard category, while Figure 5-63 displays the parcels found within either of these two liquefaction risk areas. Table 5-75 Liquefaction by Parcel Type and Risk Category, San Luis Obispo County Liquefaction Risk Category Property Type Property Count Improved Value Moderate Risk Agricultural 216 $112,651,942 Commercial 2,230 $1,539,438,419 Government/Utilities 787 $1,923,876 Other/Exempt/Misc. 1,597 $409,054,734 Residential 26,125 $5,710,198,939 Mobile/Manufactured Homes 1,330 $159,234,782 Multi-Family Residential 4,710 $1,184,672,592 Residential: Other 2,079 $622,532,626 Industrial 151 $133,363,653 Vacant 584 $162,471,832 TOTAL 39,809 $10,035,543,395 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-207 Liquefaction Risk Category Property Type Property Count Improved Value High Risk Agricultural 16 $8,129,234 Commercial 210 $68,599,828 Government/Utilities 182 $287,709 Other/Exempt/Misc. 258 $24,060,579 Residential 2177 $439,558,043 Mobile/Manufactured Homes 27 $8,729,206 Multi-Family Residential 378 $104,981,846 Residential: Other 135 $66,773,018 Industrial 8 $5,951,546 Vacant 48 $8,181,331 TOTAL 3,439 $735,252,340 GRAND TOTAL 3,439 $10,770,795,735 Source: SLO County Planning and Building, and Assessor’s Office; ParcelQuest; Wood Plc Parcel Analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-208 Figure 5-63 Parcels Within Moderate or High Liquefaction Risk Areas – San Luis Obispo County PACIFIC OCEAN Parce ls Within Liqu efaction Ri sk Are • High c Moderate Liqu efaction Ris k -Hi gh Potentia l Moderate Potentia l -+--Rail roads Hi ghway Freeway -Lakes VVaterways D eities ••• Map compiled 312019; intended for planning pu rposes only. Data Source : Sa n Lui s Ob ispo County, US Census T IG ER Database , CA Open Data Portal , Pa rcelQ uest 0 10 20 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-209 Critical Facilities and Infrastructure (Liquefaction) Liquefaction during major earthquakes can cause severe damage to infrastructures on level ground as a result of settling, titling, or floating, particularly those that may already be particularly vulnerable due to existing structural deficiencies, age, or even scouring (e.g. bridges). Table 5-76 and Table 5-77 summarize how many and which type of critical facilities (from the combination of the county-provided facilities as well as the Homeland Infrastructure Foundation-Level Data, or HIFLD layers) are found within liquefaction risk areas. The first table contains the results by jurisdiction, then the second by liquefaction risk category. These were obtained from a GIS overlay analysis of critical facilities as well as liquefaction risk layers. The majority are found in moderate risk zones within unincorporated portions of the county. Table 5-76 Critical Facilities within Liquefaction Risk Areas, by Jurisdiction Liquefaction Risk Category Count Arroyo Grande 22 Atascadero 9 Grover Beach 12 Morro Bay 17 Paso Robles 2 San Luis Obispo 69 Unincorporated 105 TOTAL 236 Source: San Luis Obispo County Planning & Building Department, HIFLD, Wood GIS analysis Table 5-77 Critical Facilities within Liquefaction Risk Areas, by Liquefaction Risk Category Liquefaction Risk Category Count Moderate 220 High 16 TOTAL 236 Source: San Luis Obispo County Planning & Building Department, HIFLD, Wood GIS analysis An analysis of bridges within areas of liquefaction risk was also performed, with the results of the overlay analysis summarized in Table 5-78 below. Bridges with critical scour conditions were counted as well, since already weakened structures of this kind would be more highly susceptible to damages or destruction during liquefaction events, further impairing transportation routes, commodity transmissions, etc. Table 5-78 Bridges and Scour Status in Liquefaction Risk Areas Liquefaction Risk Category Total Bridges Scour Critical Total Moderate 233 101 High 46 23 TOTAL 279 124 Source: Wood Analysis on National Bridge Inventory data, 2018 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-210 Historic, Cultural, and Natural Resources (Liquefaction) GIS Analysis indicates that 29 historic and cultural properties are vulnerable to liquefaction. 25 of them are found within moderate liquefaction risk areas, whereas 4 of them in high liquefaction risk areas. Details on the specific properties at risk can be obtained in Appendix E Critical Facilities. Future Development (Liquefaction) Areas slated for future development should consider potential impacts from liquefaction and soil instability, particularly development of new critical facilities in areas with vulnerable populations (e.g. schools). A GIS overlay analysis of building construction permits for residential and commercial properties was additionally performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties may be constructed, or may have upgrades completed, in moderate, high, or very high liquefaction risk areas (see Table 5-79). Table 5-79 Building Permits Submitted in Liquefaction Risk Areas from 2014-2019 Liquefaction Risk Work Class Case Type Work Class Type Total Moderate New Structure PMTR - Residential Permit 1,331 PMTC - Commercial Permit 307 Minor Use Permit Land Use 189 Conditional Use Permit Land Use 169 TOTAL 1,996 High New Structure PMTR - Residential Permit 32 PMTC - Commercial Permit 29 Minor Use Permit Land Use 71 Conditional Use Permit Land Use 7 TOTAL 139 GRAND TOTAL 2,135 Source: San Luis Obispo County Planning & Building Department, Wood GIS analysis Risk Summary (Earthquake and Liquefaction) • San Luis Obispo County is located in a geologically complex and seismically active region. There are numerous active and potentially active faults in the County. The County has a history of damaging earthquakes, including those associated with the San Andreas fault, but there have also been a number of magnitude 5.0 to 6.2 earthquakes which have affected large portions of the County. • The overall significance of earthquakes and liquefaction is high. • A moderate earthquake occurring in or near San Luis Obispo County could result in deaths, casualties, property damage, agricultural and environmental damage, and disruption of normal government and community services and activities. • The location of the epicenter as well as the time of day and season of the year would have a profound effect on the number of deaths and casualties, as well as property damage. • The hazard of earthquakes varies from place to place, dependent upon the regional and local geology. • There is significant building and other infrastructure exposed to potentially liquefiable soils ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-211 • Effects on people: Hazus probabilistic scenario modeling of worst-case ground shaking results in estimates of 200-700 people needing hospitalization and between 35-194 deaths depending on the time of day the earthquake hits. • Effects on property: Hazus probabilistic scenario modeling indicates about 39,034 buildings will be at least moderately damaged, with approximately $5.9 billion in losses. The County has removed or retrofitted the majority of unreinforced masonry buildings. • Effects on economy: The total economic loss estimated for a large earthquake is $6.3 billion, which includes building and lifeline related losses based on the region's available inventory. An estimated 16% of losses computed by Hazus were related to the business interruption of the region. • Effects on critical facilities and infrastructure: Essential facility damage (police, fire, school, medical) is predicted to be low; only 713 hospital beds (48%) would be available during the earthquake. Utility lifeline systems impacts would be significant particularly to bridges; moderate damage can be expected to water, wastewater, power and communications facilities; loss of water and power would be significant in the days and weeks following the earthquake. For the GIS analysis with the liquefaction layer, though, it was found that a total of 236 critical facilities are at risk of moderate or high liquefiable soil areas, with most of these found in unincorporated portions of the county. The Alquist-Priolo layer analysis yielded two facilities within Los Osos Alquist Priolo areas, which are seismic hazard designation areas in the unincorporated county. • Cascading and Secondary Effects: Earthquakes can cause many cascading effects such as fires, flooding, hazardous materials spills, utility disruptions, landslides, and transportation emergencies. Ground shaking may cause tsunamis or seiche, the rhythmic sloshing of water in lakes or bays. • Related hazards: Landslides, Subsidence, Tsunami Table 5-80 Earthquake Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Extensive Occasional Critical High City of Arroyo Grande Significant Highly Likely Critical High City of Atascadero Limited Unlikely Limited Low City of Grover Beach Extensive Occasional Critical High City of Morro Bay Significant Occasional Catastrophic High City of Paso Robles Significant Likely Critical High City of Pismo Beach Extensive Occasional Limited Medium City of San Luis Obispo Extensive Occasional Catastrophic High Avila Beach CSD Extensive Unlikely Critical Medium Ground Squirrel Hollow CSD Limited Occasional Negligible Medium Heritage Ranch CSD Extensive Occasional Catastrophic High Los Osos CSD Extensive Likely Critical High Nipomo CSD Extensive Likely Limited Medium San Miguel CSD Extensive Likely Critical High San Simeon CSD Significant Likely Limited High ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-212 Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance Templeton CSD Significant Unlikely Limited Low Cayucos Sanitary District Extensive Occasional Limited High Port San Luis Harbor District Extensive Likely Critical Medium San Luis Obispo FCWCD Extensive Occasional Critical High South San Luis Obispo Sanitation District Significant Highly Likely Critical High ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-213 5.3.11 Flooding Hazard/Problem Definition Floods are among the most frequent and costly natural disasters in terms of human hardship and economic loss and are usually caused by weather events. Floods can cause substantial damage to structures, landscapes, and utilities as well as life safety issues. Certain health hazards are also common to flood events. Standing water and wet materials in structures can become breeding grounds for microorganisms such as bacteria, mold, and viruses. This can cause disease, trigger allergic reactions, and damage materials long after the flood. When floodwaters contain sewage or decaying animal carcasses, infectious disease becomes a concern. Direct impacts, such as drowning, can be limited with adequate warning and public education about what to do during floods. Where flooding occurs in populated areas, warning and evacuation will be of critical importance to reduce life and safety impacts. The area adjacent to a river or stream channel is the floodplain. Floodplains are illustrated on inundation maps, which show areas of potential flooding and water depths. In its common usage, the floodplain most often refers to the area that is inundated by the 100-year flood, the flood that has a one percent (1%) chance in any given year of being equaled or exceeded. The 100-year flood is the national minimum standard to which communities regulate their floodplains through the National Flood Insurance Program (NFIP). The 500-year flood is the flood that has a 0.2 percent chance of being equaled or exceeded in any given year. A 500-year flood event would be slightly deeper and cover a greater area then a 100-year flood event. The potential for flooding can change and increase through various land use changes and changes to land surface, which can result in a change to the floodplain. A change in environment can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity. The potential for flooding can change and increase through various land use changes and changes to land surface, which can result in a change to the floodplain. A change in environment can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity. San Luis Obispo County is susceptible to various types of flood events as described below. Riverine flooding - Riverine flooding, defined as the condition when a watercourse (e.g. river or channel) exceeds its “bank-full” capacity, generally occurs as a result of prolonged rainfall, or rainfall that is combined with already saturated soils from previous rain events. This type of flood occurs in river systems whose tributaries may drain large geographic areas and include one or more independent river basins. The onset and duration of riverine floods may vary from a few hours to many days. Factors that directly affect the amount of flood runoff include precipitation amount, intensity and distribution, the amount of soil moisture, seasonal variation in vegetation, snow depth, and water-resistance of the surface due to urbanization. In the San Luis Obispo planning area, flooding is largely caused by heavy and continued rains, and heavy flow from tributary streams. These intense storms can overwhelm the local waterways as well as the integrity of any flood control structures. The warning time associated with slow rise floods assists in life and property protection. Localized flooding - Localized flooding problems are often caused by flash flooding, severe weather, or an unusual amount of rainfall. Flooding from these intense weather events usually occurs in areas ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-214 experiencing an increase in runoff from impervious surfaces associated with development and urbanization as well as inadequate storm drainage systems. Dam or Levee failure flooding - Flooding from failure of one or more upstream dams or water control structures such as levees is also a concern to San Luis Obispo County. A catastrophic flood control structural failure could easily overwhelm local response capabilities to save lives and require mass evacuations towards the north and east of the planning area. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Loss of life could result, and there could be associated health concerns as well as negative effects to local buildings and infrastructure. Dam failure is addressed in more detail under the Dam Failure section, while levee failures and other aspects related to localized flood problem areas are discussed throughout this section. Coastal flooding - Coastal foods come from the Pacific Ocean where large waves are and can be affected by storm surge. Coastal foods can be very dangerous when high waters are combined with the destructive forces of waves. In low-lying coastal areas, storm surge and flooding can reach many miles from the shoreline, flowing up rivers and across flat land (FEMA, 2018). In San Luis Obispo County, coastal flooding is attributed with the following mechanisms: (1) swell runup from intense offshore winter storms in the Pacific; (2) tsunamis from Aleutian-Alaskan and Peruvian-Chilean Trenches or other off-shore faults; (3) runup from wind waves generated by landfalling storms; (4) swell runup from waves generated off Baja California by tropical cyclones; (5) Effects of landfalling tropical cyclones (FEMA, 2012). Wave runup refers to the height above the tide and surge elevation and can depend on the local water levels, wave action, and beach structure. Coastal flooding hazards is addressed in more detail under the Coastal Storms/Coastal Erosion/Sea Level Rise section. Geographic Area The Flood Insurance Study conducted by FEMA for San Luis Obispo County noted that runoff in the streams of the county is small, with appreciable flows occurring only during and immediately after precipitation. However, during large storms stream flow increases rapidly and flood waters can contain high amounts of debris, causing major flood damage. For many of the water courses that are located in the County, areas that may be inundated in response to 100-year storm events are located adjacent to or near the stream or river channel. Since many of the County’s watercourses are located in mountainous or remote areas with little or no development, flooding events along these rivers and streams generally result in minimal impacts. Other watercourses in the County, however, have floodplains that extend well beyond the defined stream or river channel. When a flood occurs along one of these watercourses, and it is located in or near an area that is urbanized, damage to property and infrastructure can be widespread. In the southern portion of San Luis Obispo County, Arroyo Grande Creek, San Luis Obispo Creek, and their respective tributaries, flow through urbanized areas and have caused major floods. The north coast area of the county also contains several short, steep-gradient creeks that can experience rapid increases in water flows in response to storm events in Cambria. The largest water course in the inland portion of the county is the Salinas River, which is located adjacent to numerous incorporated and unincorporated communities. Other major inland water courses include the Estrella River and San Juan Creek. Due to the generally remote locations of these watercourses, flooding impacts are generally not significant. Figure 5-64 below shows the waterways located in the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-215 Figure 5-64 San Luis Obispo County Major Waterways PACIFIC OCEAN --Waterways Lakes -+--+ Railroads Highway Free way CJ cities ••• Map comp il ed 2/2019; inte nded for planning purposes only . Data Source: San Luis Obispo County, US Census TIGER Database , CA Open Data Portal Monterey Grover 0 10 20 Tulare =~=~~=-c,;;-a:a:--aa:-a:a-,;;a-a=-~-C-=-------------------- Santa Barbara Ventura 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-216 There have been several studies related to water resources and watersheds in San Luis Obispo County. Due to the varied topography, previous water-related planning efforts have identified 25 watershed areas in three sub-regions (North Coast, South County, North County) of the county. The San Luis Obispo County Stormwater Resource Plan (2018), further grouped these watershed areas into nine “Watershed Groups” based on hydrologic boundaries, previously identified watershed areas, and grouped areas of similar physiographic and land-use characteristics. Note, while this plan was being updated the County was also in the process of updating the Integrated Regional Water Management Plan (IRWMP) which will incorporate the Stormwater Resource Plan. The IRWMP update will revise the nine water planning areas into six groups. The following are descriptions of the three watershed regions in the county as they have been described in the County’s 2018 Stormwater Resource Plan. Coastal Watersheds: These watersheds drain out of the Santa Lucia Range into the Pacific Ocean. Most of the channels here are relatively short and flow to the west and southwest. In the most southerly part of this coastal region, a relatively broad coastal plain has developed from deposition of the ancestral Santa Maria River, now occupied by the communities of Shell Beach, Pismo Beach, Arroyo Grande, Grover Beach, Oceano, and Nipomo. Moving north, ancient sedimentary and metamorphic rocks of the Irish Hills limit the extent of coastal development until Los Osos Valley breaches the range front and reaches the coastline, and where the communities of Los Osos and Morro Bay are built upon the now-drowned estuary of Los Osos Creek and Chorro Creek. Even farther north, the same metamorphic rocks again encroach upon the coast without respite, leaving room only for the scattered communities of San Simeon, Cambria, and Cayucos on uplifted marine terraces only a few hundred thousand years old, plastered onto the side of the steeply descending Santa Lucia Range. Area Between the Santa Lucia and Temblor Ranges: Watersheds in this area drain north into the Salinas and Estrella rivers. These rivers meet just upstream (south) of the Monterey County line and continue north as the Salinas River enters the Pacific Ocean in Monterey Bay. Their headwaters lie far to the south—the Salinas River emerges from Santa Margarita Lake, the Estrella River from San Juan Creek, with the two separated by the northwest-trending spur of the La Panza Range. This topography not only has guided the overall drainage patterns of the central county, but also has limited the opportunities for transportation corridors to reach into this central region. Thus, the population centers in this region (Atascadero, Templeton, Paso Robles, San Miguel) are limited to the river valley below its headwaters. Southeast Corner of County: These watersheds drain either south, into the Cuyama River, or into the closed depression of the Carrizo Plain between the southern extent of the Temblor Range and the Caliente Range. There are no significant urban areas within this region, and only short, limited drainage courses down the mountain slopes into either the Cuyama River or the alluvial plain surrounding Soda Lake. Figure 5-65 from the San Luis Obispo County Stormwater Resource Plan depicts the various watershed groupings in the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-217 Figure 5-65 San Luis Obispo County Watersheds Source: San Luis Obispo County Integrated Regional Water Management Plan, 2018 ) Kings County Mont~y Coun}x Kern County Santa Barbara County- ••• County of Sa n Luis Obispo Public Works Water Resources Water Planning Areas and Watersheds Legend D :~e~~~se~~1sJ'ta~ounty Cl~~~~ter Planning Area California Department of Water Resources Bulletin 118 Groundwater Basins Water Planning Areas (WPA): WPA 2 Cayucos I Morro Bay I Los Osos 3 WPA 3 San Luis Obi5po I South County WPA 4 Cuyama River WPA s North County I/I/PA 6 Carrizo Plain 1. A modified USGS Watershed Boundary Dataset (11\,'BD ) Hydrological Unit 10 inclUded in the draft 2018 Integrated Regional Water Management (IRWM) Plan update (http :lfslocountywater .orglirwm) :2. Based on the draft 2018 lnlegrated R~ional \Nater Management (IRWM) Plan update A Date Created: 3/28/20 19 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-218 Major Sources of Flooding/Problem Areas Stream flows in the county are seasonal and generally runoff from all streams are minimal. According to the Flood Insurance Study during large storms with heavy rains the stream flows increase rapidly, and floodwaters often contain high volumes of debris that are often the cause of major flood damage. The major causes of riverine flooding in the county are the result of undersized channels with obstructions within them: small bridge opening at several highways, small culverts across local roads, and dense vegetation growth in the channels (FEMA, 2012). In addition to riverine and localized flooding, coastal communities in the county are also at risk of coastal flooding. Refer to the Coastal Storms/Coastal Erosion/Sea Level Rise section for more information on coastal flooding. Areas of San Luis Obispo County that have been mapped by FEMA as being located within the 100-year floodplain are described below. Incorporated areas of the County that have been mapped by FEMA can be found in the jurisdictional annexes. Figure 5-66 that follows the descriptions show the 100-year and 500-year floodplains and the location of levees in the county: Arroyo Grande: Areas of potential flooding in response to a 100-year storm are located adjacent to Canyon/Meadow Creek on the west side of the City of Arroyo Grande, adjacent to Corbett Canyon and Arroyo Grande Creeks in the eastern portion of the City, and a limited area along Los Berros Creek, in the southeastern portion of the City. Areas that would be inundated in response to a 100-year flood along these creeks are generally located along stream channels; however, in isolated areas, adjacent properties could be adversely affected. Near the confluence of Corbett Canyon and Arroyo Grande Creek, the 100- year floodplain widens, resulting in impacts to properties. The floodplain along Arroyo Grande Creek also widens slightly on the north and south sides of U.S. 101. Although areas subject to flooding from a 100- year flood are limited, floodwater could cause roadways to become impassable, thereby hindering travel and response efforts. Figure 5-66 depicts areas subject to inundation from a 100-year storm and does not necessarily depict areas that may be affected by local drainage problems. The City has worked to alleviate drainage problems in these areas. Atascadero: The Salinas River is located in the northeastern and eastern areas of the City of Atascadero. The floodplain of the river is generally removed from the developed areas, however, properties on the east side could be affected by flooding during a 100-year storm. The crossing of Halcon Road over the Salinas River is frequently washed-out in storm events and would be washed-out during a 100-year storm event. Atascadero Creek extends through the central portion of the City but has a limited potential for flooding impacts as the 100-year floodplain is generally confined to the channel and adjacent properties. Where Atascadero Creek crosses U.S. 101 and State Route 41, a 100-year flood could cause inundation of the portions of the highways. This would have the potential to result in significant local and regional transportation impacts. The area designated as being located within the 500-year floodplain of the Salinas River and Atascadero Creek encompasses approximately 1.5 square miles of the central portion of Atascadero. In the southeastern portion of Atascadero, flooding hazards could result from 100-year flows in several branches of Paloma Creek. Identified inundation areas are primarily located adjacent to the creek channels, although some more extensive areas could also be affected. In the western portion of the City, flooding along Graves Creek would primarily be restricted to the stream channel. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-219 Figure 5-66 below shows areas subject to inundation from a 100-and 500-year storms and does not necessarily depict areas that may be affected by local drainage problems. Atascadero has historically experienced drainage and related flooding problems in an area known as the Amapoa/Tecorida Basin, which is located to the east of Atascadero Creek and Morro Road, and south of U.S. Highway 101. This area has been subject to building moratoriums and fee programs to pay for drainage improvements. In recognition of this drainage problem, the lower portion of the basin has a Flood Hazard overlay zoning designation. The Amapoa/Tecorida drainage basin has been prone to flooding for a variety of reasons. The primary cause of flooding in this area is the result of storm events which because water flows in Atascadero Creek, greater that the 17-year design storm, to overtop the Atascadero Lake spillway channel banks and flow into the Amapoa/Tecorida basin. Other factors that have contributed to inadequate drainage in this area include flat topography and low water velocities increasing run-off volumes due to urban development, undersized drainage culverts and channels, particularly at Highway 101, and the lack of a formal method to maintain existing drainage facilities on private property. A variety of control strategies for correcting the drainage deficiencies of the Amapoa/ Tecorida area has been proposed. These measures include improvements to the Atascadero Lake spillway, construction of a new storm drains along Highway 41, requiring drainage analysis for projects located within the basin that increase building density, and provision of a mechanism to facilitate the maintenance of drainage facilities on private property. Construction of the storm drain along Highway 41 has already begun. Grover Beach: Isolated areas of potential flooding in response to a 100-year storm are located in the northern and western portions of the City of Grover Beach that are adjacent to Meadow Creek. Flood hazard areas in the northern portion of the City are restricted to an area south of U.S. 101 and north of Nacimiento Avenue. A mobile home subdivision is located in this area. In the western part of the City, flooding could affect areas located west of the Union Pacific Railroad tracks. Figure 5-66 depicts areas subject to inundation from a 100-year storm and does not necessarily depict areas that may be affected by local drainage problems. Local flooding conditions currently exist in two isolated areas within the City where properties are located below street level. Morro Bay: Flooding in the City of Morro Bay could occur as a result of flows in Morro Creek, Little Morro Creek, Chorro Creek, and the several smaller creeks located in the northern portion of the City. Flooding from these creeks could potentially render State Highway 1 bridges over these waterways unusable during a major storm. During the rains of 1995 Highway 1 was closed through Morro Bay due to flooding. Flooding from Chorro Creek would affect the eastern portion of the City. In 1995, flooding from Chorro Creek inundated Twin Bridges (now Chorro Creek Bridge) for several days, forcing travelers from Los Osos to detour through San Luis Obispo in order to reach Morro Bay. The new Chorro Creek Bridge, completed in 1996, was constructed at a higher elevation than Twin Bridges to avoid future closures due to flooding. The creeks located in the northern portion of the City traverse areas that have been extensively developed with residential uses. In 1995, houses located along Alva Paul Creek, and other houses in north Morro Bay, were flooded. Also, the area between Highway 41 and Radcliffe Street flooded in 1995 causing much ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-220 property damage to both residences and businesses. In the isolated areas where the creek floodplains extend beyond the stream channels, flooding impacts could also be significant. Paso Robles: Several watercourses are located within the City of Paso Robles that have the potential to cause flooding impacts. The Salinas River is the major watercourse located in Paso Robles and runs through the center of the City. Flows in the Salinas River that could result from a 100-year flood are primarily contained in the river channel. On the west side of the City, flooding from Mountain Springs Creek could affect isolated residential areas. The area located adjacent to and west of U.S. 101 could also be inundated by runoff from a 100-year storm. A 100-year flood event could result in the inundation of areas in the southwestern portion of the City. In the eastern portion of the City, several unnamed creeks have 100-year floodplains that would primarily affect the creek channel and adjacent properties. In the northern portion of the City, Huerhuero Creek could cause isolated areas of flooding along the road that leads to the Paso Robles Municipal Airport. Pismo Beach: The City of Pismo beach has two areas with potential flood hazards: the Pismo Creek/Price Canyon and Meadow Creek/Pismo Marsh drainage ways. Since major flooding in 1971, the City, with the aid of the Army Corp of Engineers, has made alterations to Pismo Creek channel to reduce flood hazard. Existing floodplain maps prepared prior to the creek improvements show that substantially developed areas in the city’s commercial core and Pismo Creek Planning Areas could be subject to flooding from a 100-year storm. The majority of the Meadow Creek floodplain within the city limits is contained within the State Department of Fish and Wildlife controlled Pismo Lake Ecological Preserve (Pismo Marsh). The preserve is bounded on all sides by slopes which rise over the 100-year level of flood, thus containing flooding within the preserve boundary. Meadow Creek leaves the preserve at State Highway 1 which crosses the creek via a low-lying bridge. The creek flows into the North Beach Campground where it divides into two channels one flowing into the ocean and the other flowing southward into the Grover Beach area. The creek channel floods State Highway 1, the commercial property to the north of the creek at State Highway 1, and the North Beach Campground during periods of heavy storm flows. The level of flooding is affected by tidal conditions. City of San Luis Obispo: The City of San Luis Obispo is traversed by several creeks, including San Luis Obispo Creek and its major tributaries, Stenner Creek, Brizzolara Creek and Prefumo Creek. The 100-year floodplains for these creeks encompass extensive areas of the City on the east and west sides of U.S. 101, including the downtown area. Historic flooding on San Luis Obispo Creek, such as the floods of 1969, 1973, and 1995, have resulted in substantial property damage and loss of life. Several areas in the downtown of San Luis Obispo are subject to localized flooding. Unincorporated Communities The areas of unincorporated communities that have been mapped by FEMA as being located within the 100-year floodplain are described below. South Bay: The South Bay area of the County (including the communities of Baywood Park, Los Osos, and Cuesta-by-the Sea) has not been identified as being located within a 100-year storm floodplain by the most recent Flood Insurance Rate Maps (FIRMs). Flooding in response to a 100-year storm is generally ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-221 confined to shoreline areas surrounding Morro Bay. There are locations in this area, however, that are subject to chronic localized flooding. After a significant rain, localized flooding occurs throughout the Los Osos area. Numerous intersections within the community experience flooding during storm events. Cambria: Santa Rosa Creek has a history of flooding which has caused severe erosion of the creek banks as well as damage to phone and gas lines, water wells, and bridges. Major bank erosion in the past has caused complete interruption of the town’s water supply. The 100-year floodplain for Santa Rosa Creek is generally confined to the creek channel and surrounding areas south of Main Street. However, the West Village business area along Main Street has been subjected to severe flooding as a result of recent flood levels that overtopped the banks of Santa Rosa Creek. A creek bypass and West Village Storm Drain system constructed in 2009 has significantly reduced, but not eliminated, this potential flood scenario. Cayucos: The 100-year flood areas near the community of Cayucos are predominately confined to areas adjacent to Cayucos Creek, Little Cayucos Creek, and Willow Creek. Several limited areas of the community along these areas have been designated as being in a 100-year floodplain. Nipomo: Flooding in the community of Nipomo occurs primarily along Nipomo Creek and its tributaries, such as Deleissiques Creek and Mehlschau Creek. The 100-year and 500-year floodplains along these creeks encompasses areas adjacent to the watercourses, along with extensive areas located east and west of U.S. Highway 101. Oceano: Flooding in Oceano is a result of heavy flows in Arroyo Grande Creek and Meadow Creek. The most significant inundation area is near the creeks’ confluences with the ocean. Areas subject to flooding as a result of a 100-year storm generally extend south of State Highway 1 and west of Halcyon Road. The Arroyo Grande Creek channel has limited storm capacity and has potential of overtopping levees through town. An emergency response plan has been adopted to address potential breach of levees and the wide spreading flooding that may result. Flooding within the town generally occurs at the Oceano County Airport and the Sanitation District Wastewater Plant, along with the residential neighborhoods in low- lying areas around these facilities in particular. This area was subject to the greatest extent of damage in the December 2010 storm. San Margarita: Yerba Buena Creek, which drains a significant watershed, runs through the community and continues north toward before joining Santa Margarita Creek which empties into the Salinas River. The shadowing effect of Santa Lucia Range to the south of the community tends to limit the amount of rainfall. Localized flooding occurs due to potential creek flows and the flat terrain inhibiting runoff to the creeks. Templeton: Watercourses located in and near the community of Templeton include the Salinas River and Toad Creek. The 100-year floodplain of the Salinas River as it passes to the east of the community is confined to the river channel and does not significantly affect the town. The floodplain for Toad Creek is not extensive. The 100-year flood along this watercourse would have the potential to affect adjacent properties most notably along Salinas and Eddy Streets and an area between Route 101 and Main Street at the north edge of town. San Miguel: The community of San Miguel is located west of the Salinas River, and north of the confluence of the Estrella River with the Salinas River. Properties in the 100-year floodplain are primarily located on the lower terrace. Because of the lack of storm drains, low points in the community are sometimes inundated during periods of heavy rainfall. These areas are generally along N Street and ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-222 Mission Street between 12th and 16th Streets. A comprehensive drainage study was prepared for San Miguel in 2003 and the associated drainage plan is being implemented incrementally as new development occurs. Creston: The community of Creston is located between the west and middle branches of Huerhuero Creek. The 100-year floodplains of these creeks are located adjacent to the western and eastern edges of the community and could have the potential to affect adjacent developed properties. Shandon: The community of Shandon is located southwest of the confluence of San Juan Creek with the Estrella River. The 100-year floodplains of these watercourses are not located within the town of Shandon but are located adjacent to developed areas. These water courses also cross State Routes 41 and 46 near the town. Flooding along these watercourses could have the potential to adversely affect access to and from the community. Rural Areas: Many other areas in the unincorporated portion of San Luis Obispo County are isolated or residents and travelers in these rural areas of the County may need to take excessively long detours during and after floods due to flood impacts on roads. Road impacts are considered a significant flood impact and potential safety risk. In 1997 after the Logan fire, severe rains took out California Highway 166 and two CHP officers and two civilians died, in addition to property loss. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-223 Figure 5-66 FEMA Special Flood Hazard Zones 100- and 500-Year Events -t -<,-, ,,,,,;,,.. Monterey ~vei. ~~-~----------~ ~ ~ ~ I PACIFIC OCEAN FEMA N F H L -1 % A nn ua l Chance -0.2% An nua l Cha nce Levees Waterways Lakes -+--+ Railroads --Hi ghway --Freeway D eities Ma p compiled 2 /20 19 ; Nac1111ie111 Res'"), · inte nded for plan ning pu rposes only. Data Source : Sa n Luis Obispo County, US Ce nsus TIG ER Data base , CA Open Data Porta l, FEM A N FHL ••• Grov er o Kings Tulare I I -------------------·---------- Poso C reek Kern Santa Barbara Ventura 10 20 40 M iles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-224 Flood Control Zones The San Luis Obispo County Flood Control and Water Conservation District (the District) was founded in 1945 with the purpose “to provide for control, disposition and distribution of flood and storm waters of the district and of streams flowing into the district…”. The District provides general funding to help communities identify flooding problems, recommend solutions, and help implement projects and establishes zones of benefit to fund specific mitigation projects. The District established the following major flood control zones: Zone 1: Arroyo Grande Creek Channel/Zone 1A: Los Berros Diversion Channel of Arroyo Grande Creek Within this flood control zone, the District is focused on improving the maintenance of Zone 1/1A flood control facilities and has developed a long-term maintenance plan for the channel (Refer to the section below, Levees of Concern, for more information on flooding concerns related to the failure of the Arroyo Grande Levee System). On July 18, 2006, the District’s Board of Supervisors adopted Resolution No. 2006- 245 to provide levy assessments on the parcels within both Zone 1 and 1A. Levy assessments provide $350,000 in funding annually, which allows for the District to provide substantially enhanced maintenance and operation efforts of the Arroyo Grande and Los Berros Channels within Zone 1/1A. Zone 3: Arroyo Grande Creek Zone 3 encompasses the communities within the Five Cities. In Zone 3 the District funds the operations of the Lopez Projects which includes Lopez Lake and Dam, Lopez Terminal Reservoir, Lopez Water Treatment Plan and Distribution System. Zone 3 is a wholesale water supplier to the communities of Arroyo Grande, Avila Beach, Grover Beach, Oceano CSD and Pismo Beach. Zone 9: Areas encompassing San Luis Obispo Creek and its tributaries Zone 9 was established in 1973 and provides flood control services for the San Luis Obispo Creek watershed (Coastal watershed). This watershed begins in the foothills of the Santa Lucia Range and flows 18 miles to discharge into the Pacific Ocean at San Luis Bay near Avila Beach. The San Luis Obispo Creek follows closely along the route of State Highway 101. The District notes that the Creek and its tributaries have recurring damaging floods and bank instability that require active channel management. The Zone 9 Advisory Committee was formed to assist the County Board of Supervisors on policy decisions related to Zone 9, as well as assist in determining the needs, desires and financial capabilities of property owners within Zone 9. The Advisory Committee also provides recommendations on specific flood control projects. In March 2003 the San Luis Obispo Waterway Management Plan was developed and adopted. The Plan consists of three volumes. Volume I provide a detailed hydrology and hydraulic analysis of the watershed and its tributaries, identification of management problems to address flooding, bank instability, habitat protection and enhancement, and a preferred project for implementation. Volumes II provides information on the stream management and maintenance program and identifies an approach to routine maintenance including Best Management Practices. Volume III is the drainage design manual to assist in determining criteria for design of drainage channels, storm drain systems, storm water detention and facilities within Zone 9. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-225 Levee Failure A levee is a raised area that runs along the banks of a river or canal. Levees reinforce the banks and help prevent flooding. By confining the flow, levees can also increase the speed of the water. Levees can be natural or man-made. A natural levee is formed when sediment settles on the river bank, raising the level of the land around the river. To construct a man-made levee, workers pile dirt or concrete along the river banks, creating an embankment. This embankment is flat at the top, and slopes at an angle down to the water. For added strength, sandbags are sometimes placed over dirt embankments. Levees provide strong flood protection, but they are not failsafe. Levees are designed to protect against a specific flood level and could be overtopped during severe weather events. Levees reduce, not eliminate, the risk to individuals and structure behind them. A levee system failure or overtopping can create severe flooding and high-water velocities. It’s important to remember that no levee provides protection from events for which it was not designed, and proper operation and maintenance are necessary to reduce the probability of failure. Levees of Concern There are two levees of concern that are noted in the County’s Dam and Levee Failure Evacuation Plan (2016), the Arroyo Grande Creek levee and Santa Maria River levee. Each is further described below. Arroyo Grande Creek Levee System The lower Arroyo Grande Creek, or Cienaga Valley lies at the downstream, lower gradient terminus of a large watershed, causing it to be especially vulnerable to flooding. Severe flooding from the Arroyo Grande Creek in the 1950s resulted in inundation of farmland and had significant impacts on infrastructure. As an outcome of the severe flooding, the community organized the Arroyo Grande Creek Flood Control Project (Project). The main element of the project is a levee system and trapezoidal channel that confined the Arroyo Grande Creek in levees from its confluence with Los Berros Creek downstream to the Pacific Ocean. Runoff from Pismo Lake that travels through Meadow Creek, enters the Arroyo Grande Creek through a pair of flap gates near the Oceano Dunes State Vehicular Recreation Area. The Project was completed in 1961 and was constructed to convey the design capacity of 7,500 cubic feet per second (cfs) with two-feet of freeboard. The original constructed channel was designed to provide flood protection from a 50-year recurrence interval. Since the completion of the project the channel has lost significant capacity due to challenges to maintain the channel. According to the Arroyo Grande Creek Erosion, Sedimentation, and Flooding Alternative Study (2006) the existing capacity of the channel is estimated to be 2,500 cfs providing flood protection from a storm with only a 4.6-year recurrence interval, or a chance of overtopping every 4.6 years. The Arroyo Grande Creek Levees have experienced failure by high water overtopping in the past. Refer to Previous Occurrences below for further details. Figure 5-67 below depicts the Arroyo Grande Creek Levee system. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-226 Figure 5-67 Arroyo Grande Levee System Source: San Luis Obispo County Flood Control and Water Conservation District ••• Levee System -North Levee -South Levee Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-227 Santa Maria River Levee The Santa Maria River Levee was designed and built by the U.S. Army Corps of Engineers (USACE) from 1959 to 1963 and is now owned and operated by the Santa Barbara Department of Public Works’ Flood Control District (Dam and Levee Failure Plan, 2016). The San Luis Obispo County’s Flood Control District also provides some funding towards the maintenance of the levee as part of the minor flood control for Zone 4. Zone 4 collects service fees from properties in the County of San Luis Obispo that receive flood protection form the levees and reimburses the Santa Barbara District for its maintenance services (San Luis Obispo County Flood Control and Water Conservation District 2009). The levee runs along the Cuyama River, the same river which would be affected by a failure of the high hazard dam, Twitchell Dam, (Refer to the Dam Failure section for information specific to the Twitchell Dam). The Santa Maria River Levee is built of river sand and the portion facing the river is covered with a layer of rock. The levee is not certified by the USACE to withstand a 100-year flood. Floodplain Mapping FEMA established standards for floodplain mapping studies as part of the National Flood Insurance Program (NFIP). The NFIP makes flood insurance available to property owners in participating communities adopting FEMA-approved local floodplain studies, maps, and regulations. Floodplain studies that may be approved by FEMA include federally funded studies; studies developed by state, city, and regional public agencies; and technical studies generated by private interests as part of property annexation and land development efforts. Such studies may include entire stream reaches or limited stream sections depending on the nature and scope of a study. A general overview of floodplain mapping is provided in the following paragraphs. Details on the NFIP and mapping specific to participating jurisdictions are in the jurisdictional annexes. Flood Insurance Study (FIS) The FIS develops flood-risk data for various areas of a community that is used to establish flood insurance rates and to assist the community in its efforts to promote sound floodplain management. The current San Luis Obispo County FIS is dated November 16, 2012. This study covers both the unincorporated and incorporated areas of the County. Flood Insurance Rate Map (FIRM) The FIRM is designed for flood insurance and floodplain management applications. For flood insurance, the FIRM designates flood insurance rate zones to assign premium rates for flood insurance policies. For floodplain management, the FIRM delineates 100- and 500-year floodplains, floodways, and the locations of selected cross sections used in the hydraulic analysis and local floodplain regulation. According to the HMPC, FEMA Region IX is currently conducting survey and field reconnaissance through October 2019, in four study areas in the County; (1) an area of the Salinas River north of the City of Paso Robles; (2) An area of the Huerhuero Creek; (3) areas of the San Luis Obispo Creek in the southern part of the City of San Luis Obispo and in the Avila Beach area; (4) an area of Meadow Creek through the cities of Pismo Beach and Grover Beach. Following the survey and field, FEMA Region IX will perform hydrology and hydraulics analysis and develop floodplain mapping, flood risk products and work maps by May 2020. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-228 Extent (Magnitude/Severity) San Luis Obispo County is large and is characterized by its extremely diverse terrain. This varying and diverse terrain when viewed in combination with flood maps can be an indicator of flood extent Together, coastal terrain and narrow valleys, flood depth, and velocity affect the extent of flood hazards and resulting damage in the County. Deeper and faster flood flows can damage communities in the County. However, shallow flooding with higher flows can cause similar damage. The Santa Lucia Mountain Range, which curves from the northwest to the southeast to form a barrier between the coast and interior areas; leading to more precipitation on the coast compared to the interior areas (Refer to the Adverse Weather section for more information on differences in precipitation throughout the county). The coastal plain in the North Coast Area from Morro Bay to Cambria in the north, consists of a narrow beach that backs up to the Santa Lucia Range and is cut by a number of stream valleys that empty into the Pacific Ocean. The southern coastal plain area between Arroyo Grande and Morro Bay is characterized by valley and mountain ridges. The lower reaches of the valleys are formed by broad alluvial plains that open to the ocean. While the upper reaches of the valleys are narrow and end in steep mountain canyons. During the winter and spring months the County experiences heavy rain events that cause high runoff into the river systems. Issues arise when the runoff carries debris and sediment that overwhelm the County’s drainage infrastructure. To prevent flooding, a wide variety of storm drainage and flood control measures are used throughout the County to prevent issues with high runoff. These include flood control reservoirs, levee systems, and watershed treatments. In developed areas, storm drainage systems composed of street gutters, inlets, underground storm drains, ponds, pumping stations, and open channels are used to collect and control stormwater runoff. The storm drainage and flood control systems are discussed further in the sections that follow. Figure 5-64 illustrates major natural and manmade waterways in the county. The map that follows, Figure 5-68 depicts the diverse topography of the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-229 Figure 5-68 San Luis Obispo County Topography Source: San Luis Obispo County Public Works, Water Resources Division Monterer. Gountr. Kern Gountr. Pis Grover B 0 ••• Co unty of San Lu is Obispo Pu blic Works Water Resources Topography Legend Highways = US HIGHWAY -STATE HIGHWAY □ ;~~~ater Planning Area Elevation in Feet Hig h : 5103 Low: O Water Planning Areas (WPA): Ci) 0 0 WPA 1 San Simeon /Cambria WPA 2 Cayucos / Morro Bay / Los Osos WPA 3 South COl.lnty or San Luis Obispo/South County © WPA 4 Cuyama River ® WPA 5 Salinas / Estrella or North County @ I/I/PA 6 Carrizo Plain 1. Based on the draft 2016 Integrated Regional water Man~ement {IR WM} Plan update (http:/iSlocounty.-.ater.orgJirwm} N A Dat e Created: 3/29/2019 Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-230 Levee Failure Extent The magnitude and severity of the levees of concern for the County (Santa Maria and the Arroyo Grande Levees) as described in the 2016 Dam and Levee Evacuation Plan are as follows, Arroyo Grande Creek Levee System Under the current conditions of this levee system (refer to Levees of Concern) the county estimates the channel will likely overtop the south levee between State Highway 1 and the 22nd Street bridges (Dam and Levee Failure Evacuation Plan, 2016). The threat of flooding related to the Arroyo Grande Creek levee failing will be confined to areas immediately adjacent to levees as well as the potential for damage in low- lying areas less than 50-feet above mean sea level and are immediately adjacent to the Arroyo Grande Creek levees. According to the County’s Evacuation Plan for dam and levee failure, critical facilities of concern of failure of the Arroyo Grande Creek Levee include the South County Sanitation District’s waste water treatment plan and the Oceano Airport; both of which are located adjacent to the north levee of the channel between the mouth of the Arroyo Grande Creek and the Union Pacific railroad bridge (Dam and Levee Failure Evacuation Plan, 2016). The County expects flooding due to levee overtopping or breaching to damage roadways, communication systems and infrastructure, with the areas most at-risk of the Arroyo Grande Creek Levee system failing being those adjacent to the channel and within in the 100-year floodplain. Santa Maria River Levee The USACE reviewed inspected the Santa Maria River Levee in 2006 as part of a systematic assessment of flood control structure and facilities in the United States following the events of Hurricane Katrina. In March 2006, after inspecting the Santa Maria River Levee the USACE placed the levee on the national list of levees at risk of failure and denied certification that the levee could withstand a 100-year flood event. The Santa Maria River Levee will be affected by a failure of the Twitchell Dam. The community that will most likely be impacted is the City of Santa Maria which borders the County of San Luis Obispo and is located in Santa Barbara County. The Santa Barbara Flood Control District is responsible for the levee. Previous Occurrences San Luis Obispo County has experienced severe flooding events that have resulted in extensive property damage. Flooding hazards are most likely to exist along major river and stream courses including the Salinas River, San Luis Obispo Creek, Santa Rosa Creek, Arroyo Grande Creek, Morro Creek and Huerhuero Creek. Areas that have been recently affected by flooding impacts are the areas most to be likely to be affected by future events. Therefore, a historical perspective of the effects of recent flood events can provide useful insight in land use planning and reduction of future flood hazard risks. The following table contains a list of previous flooding events throughout the County over the past fifty years. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-231 Table 5-81 Major Floods in San Luis Obispo County Date of Event Incident Description January-February 1969 A series of storms delivered 12-21 inches of rainfall over an 8-day period. In February, another storm brought over 5 inches of rain. The most severe damage to urban property occurred in the City of San Luis Obispo, where San Luis Obispo Creek channel filled with debris and flow over-topped the channel banks and onto the city streets. Severe damages were sustained by streets, highways, and utilities through-out the County. In Cambria, the water-supply system was damaged. The sewage-treatment plants at Morro Bay, Avila Beach, and Pismo Beach were inundated by both floods. January, 1973 Unusually heavy rainfall occurred over a 10-hour period. San Luis Obispo Creek, and its tributary, Stenner Creek, overtopped their banks and inundated a wide area of downtown City of San Luis Obispo. February 22, 1993 This flash flood occurred in a 2-hour period causing $500,000 damage to four businesses and several residences. 2.5 inches of rain in total were reported. January and March, 1995 Serious flooding occurred in all coastal and many inland streams. Extensive damaged occurred in the City of San Luis Obispo and the San Luis Obispo Golf Course. Cambria had up to 6 feet of water in areas. February 2, 1998 Heavy rain drenched the entire area causing an average of rainfall totals that ranged from 2 to 8 inches over coastal areas, up to 12 inches in the mountains. Widespread flooding was reported in all areas. Forty homes were flooded in Solvang and 15 homes were flooded in Ojai. Flooding and mudslides closed parts of most major roadways across the area including State Highways 1, 33, 101, 118, 126, 150, 154, 166 and the 246. Refer to the Adverse Weather Past Events tables for more information on the rain, and wind hazards that were associated with this event. November 28, 1998 Moderate rain produced local street flooding in several Central Coast communities including Santa Maria, Lompoc and Pismo Beach. May 5, 1998 Heavy rain produced flash flooding and mudslides across Southern San Luis Obispo County and closed portions of State Highway 166. Rainfall totals ranged from 1 to 3 inches over coastal areas, up to 6 inches in the mountains. Numerous flooding problems were reported across the area. January 31, 1999 Urban flooding, along Los Osos road, was reported in the City of San Luis Obispo. January 8, 2001 Heavy rain produced street flooding in the city of Pismo Beach. January 11, 2001 An extremely large swell combined with high astronomical tides produced heavy surf and flooding of coastal areas along Central and Southern California. March 4-5, 2001 Heavy rain produced numerous flooding. In Oceano, the Arroyo Grande Creek overflowed, destroying numerous crops and damaging one home. Also, the Pacific Dunes RV Park was flooded, stranding several residents. In Arroyo Grande, flooding along Corbett Creek damaged four homes and five classrooms in Arroyo Grande High School. In Pismo Beach, flooding along Pismo Creek damaged some homes in Pismo Court Village. In Nipomo, several small streams flooded, damaging 20 to 30 homes. In Creston, the heavy rain produced widespread urban flooding. December 30, 2004 The heavy rain resulted in numerous reports of urban and rural flooding. In Lopez Canyon near Paso Robles, a 62-year-old man was swept down a flooded creek. Refer to the Adverse Weather section for details on heavy rain amounts related to this event. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-232 Date of Event Incident Description Late December of 2005 and early January 2006 In late December of 2005 and early January 2006, a series of storms battered the County. Most of the damage occurred New Year’s Eve and New Year’s Day. High winds and saturated soils resulted in significant tree falls particularly in the Cambria area where heavy damage was reported to a number of homes and businesses. There was one fatally which was a result of a tree falling on a pick-up truck while it was traveling on U.S. Highway101 in the Paso Robles area. Damage estimates for both private property loss and the loss and cost to local governments totaled approximately $3,000,000. November 21, 2010 An early season storm dropped down across Central and Southern California, bringing heavy rain and flash flooding. The storm produced two impulses of rainfall between November 19th and 21st. The heaviest rainfall occurred across San Luis Obispo, Santa Barbara and Ventura Counties with rainfall totals ranging from 0.50 to 1.50 inches across coastal areas to between 1.50 and 4.00 inches in the foothills and mountains. California Highway Patrol reported flash flooding in southern San Luis Obispo County. Due to heavy rain, the roadway was completely washed away at the intersection of State Highway 1 and Division Street. December 19, 2010 A series of and slow-moving storms brought heavy rain, strong winds and light snow to the area. The most severe damages began on December 19, with primarily affected areas in the South County, particularly in the Oceano area. Damages reported to Cal EMA were just over $2,000,000 in private property losses and an estimated cost and loss total to local governments of just over $1,100,000 for a total storm damage cost estimate of approximately $3,135,000. June 10, 2015 The combination of remnant moisture from Hurricane Blanca and an upper level low pressure system off the Central California coast brought strong thunderstorms to interior sections of San Luis Obispo and Santa Barbara counties. Flash flooding and mud/debris flows were reported just east of the community of Cuyama. California Highway Patrol reported flash flooding at the intersection of Highway 33 and Highway 166. May 6, 2016 A moist and unstable atmosphere generated thunderstorms and flash flooding across inland sections of Santa Barbara and San Luis Obispo counties. Due to flash flooding and mud and debris flows, sections of State Highways 46 and 166 were closed. California Highway Patrol reported flash flooding and mud and debris flows across sections of Highway 46, northeast of Shandon. Source: NCEI Storm Events Database, 2014 SLO County LHMP More recently severe winter storms occurred during February and March 2019 in San Luis Obispo County. Atmospheric rivers brought heavy amounts of precipitation to the Central Coast region causing the Salinas River, one of the largest rivers in the County, to flood multiple times. In February, a woman was rescued from the flooded Salinas River in Paso Robles by the Paso Robles Fire Department. She was transported to the hospital and was expected to recover from the incident (KEYT, 2019). In March, after heavy rains the Salinas River’s water raised quickly causing the river to flood once more. In Atascadero south of the Highway 41 bridge, five people, five dogs and one cat were rescued from the Salinas River after they were stranded on an island in the middle of the river. The group was rescued by Atascadero Fire and Emergency Services using swift water rescue equipment to wade through the high water and bring the people and animals back to the shore safely. No injuries were reported (Atascadero News, 2019). ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-233 Levee Failures The following levee failure event was noted in the 2016 San Luis Obispo County Dam and Levee Failure Evacuation Plan: In March 2001 following a heavy rain event, the Arroyo Grande levee system was breached on the south side between the mouth of the Arroyo Grande Creek and the Union Pacific railroad bridge. Hundreds of acres of farmland in the Cienega Valley as well as several residences were flooded. Impacts from the levee failure and resulting flooding lasted beyond the winter months due to the clay soils in the southern portion of the valley that remained saturated for months later. The northern levee did not fail and was able to protect several residential developments, and the regional wastewater treatment plant that serves Arroyo Grande, Oceano, and Grover Beach. Failure of the north levee of the Arroyo Grande levee systems would be a significant risk to property and human lives. The following figure, taken from the Arroyo Grande Creek Channel Waterway Management Program Final Report, 2010, are pictures of the levee failure event. Figure 5-69 Arroyo Grande Levee Failure Event, March 2001 (Looking South) Source San Luis Obispo County OES , taken during storm damage assessment, March 2001 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-234 Figure 5-70 Image of Past Flooding in San Luis Obispo County Figure 5-71 Image of Past Flooding in San Luis Obispo County ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-235 Figure 5-72 Image of Past Flooding in San Luis Obispo County Probability of Future Occurrences 100-Year Flood Likely—The 100-year flood is the flood that has a one percent chance in any given year of being equaled or exceeded. <100-Year Flood/Outside the 100-Year Floodplain Highly Likely—Based on historical data, flooding events less severe than a 100-year flood and those outside of the 100-year floodplain occur frequently during periods of heavy rains. Climate Change Considerations There are two types of flooding that will be exacerbated by climate change, coastal flooding related to sea level rise and inland flooding due to the projected increase in the precipitation which may also lead to levee or dam failure due to overtopping. The discussion in this section focuses on inland flooding. Refer to the Coastal Storms/Coastal Erosion/Sea Level Rise section for climate change considerations related to coastal flooding. California’s Fourth Climate Assessment found that costs associated with direct climate change impacts by 2050 will be dominated by human mortality, coastal damage, and the potential for droughts and mega- floods (California Natural Resources Agency 2018). Scientific studies outlined in the same assessment also indicated shifts in California’s precipitation regime, which show more dry days, more dry years, a longer dry season, and increases in occasional heavy precipitation events and floods. Studies also project great storm intensity with climate change, resulting in more direct runoff and flooding (California Natural Resources Agency 2018). As a result, high frequency flood events in conjunction with heavy precipitation events and extreme storm events will increase with climate change. Certain climate studies noted in the Fourth Climate Assessment also forecast that during periods with heavy rain and frequent storm events ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-236 there is an increase in flood events, as well as landslide and debris flow (California Natural Resources Agency 2018). For example, during the 2016-2017 winter, the storms resulted in many secondary hazards, including numerous landslides and in some watersheds an increased sediment load. Also, with wildfires already being a problem in California, increasing periods of drought and lack of precipitation are expected to exacerbate conditions for fires to occur, and in turn worsen the potential for runoff and flooding associated with burned areas. The Fourth Climate Assessment also includes nine reports for the nine regions in California. According to the Central Coast Summary Report projected flooding over the next century, including erosion and cliff retreat hazards will threaten many Central Coast communities (California Natural Resource Agency 2018b). The report notes that the Coastal Storm Modeling System (CosMoS), which is a modelling approach to comprehensively assess the physical and socioeconomic impacts of climate changes, will have projections for the entire central coast region by early 2019 (California Natural Resources Agency 2018a). Currently, the mapping has been completed for all of Southern California, including Santa Barbara County from Ventura County up to Point Conception. Refer to the Coastal Storms/Coastal Erosion/Sea Level Rise section for more information related to climate change effects for San Luis Obispo County. Vulnerability While there are some benefits associated with flooding, such as the replenishment of beach sand, and nutrients to agricultural lands, it is considered a hazard to development in floodplains. Floods can cause many cascading effects. Fire can break out as a result of dysfunctional electrical equipment. Hazardous materials can also get into floodways, causing health concerns and polluted water supplies. In many instances during a flood, the drinking water supply will be contaminated. During the 2019 update the following vulnerability analysis using GIS was performed. General Property Historically, San Luis Obispo County has been at risk to flooding primarily during the winter and spring months when river systems in the county swell with heavy rainfall. Normally, storm floodwaters are kept within defined limits by a variety of storm drainage and flood control measures. But occasionally, extended heavy rains result in floodwaters that exceed normal high-water boundaries and cause damage. Flooding has occurred in the past within the 100-year floodplain and in other localized areas. Methodology A flood vulnerability assessment was performed for San Luis Obispo County using the following GIS methodology. The County’s parcel layer and associated assessor’s building improvement valuation data were provided by the County and were used as the basis for the inventory. San Luis Obispo County’s effective Digital Flood Insurance Rate Map (DFIRM) was used as the hazard layer. A DFIRM is FEMA’s flood risk data that depicts the 1% annual chance (100-year) and the 0.2% annual chance (500-year) flood events; this data is incorporated into the National Flood Hazard Layer (NFHL). San Luis Obispo County’s effective FEMA DFIRM, dated May 16, 2017, was determined to be the best available floodplain data. Table 5-82 summarizes the flood zones included on these maps. Note, while this Plan was in the process of being written, the county was also in the process of updating their flood insurance maps. GIS was used to intersect the parcel boundaries with a master address point layer to obtain number of buildings per parcel. The parcel layer was then converted into a centroid, or point, representing the center of each parcel polygon. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-237 Only parcels with improvement values greater than zero and center points were used in the analysis, this method assumes that improved parcels have a structure of some type. The DFIRM flood zones were overlaid in GIS on the address points and parcel centroid data to identify structures that would likely be inundated during a 1% annual chance and 0.2% annual chance flood event. This overlay can be seen graphically in the regional maps in Figure 5-73, and in more detail in the jurisdictional annexes. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-238 Figure 5-73 San Luis Obispo County Parcels in Flood Zones ••• PACIFIC OCEAN Pa rcels Withi n Flo odplains • 100-Year o 500-Year • 1 DO-Yea r Coastal FEMA NFHL -1%Ann ua l Chan ce -0.2% Annual Chance 1 % An nual Chance -Coastal \1\/aterways Lake s -+--+ Railroads Highway Freeway C ities Map compiled 3/2019 ; intended for planning purposes o nly . Data Source: San Lui s Obispo Cou nty, US Census TI GER Database , CA Open Data Portal , FEM A NFHL, ParcelQuest Monterey 0 10 I I I Kings I Tulare I j ----·-------------------- PvsuCrt:ek Kern Santa Barbara 1 '------L_ Ventura 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-239 Table 5-82 San Luis Obispo County’s Flood Zones Flood Zone Definition Special Flood Hazard Areas (SFHA) Subject to Inundation by 100-Year Flood Zone A No base flood elevations determined Zone AE Base flood elevations determined Zone AH Flood depths of 1-3 feet (usually areas of ponding); base flood elevations determined Zone AO Flood depths of 1-3 feet (usually sheet flow on sloping terrain); average depths determined; for areas of alluvial fan flooding, velocities also determined Zone AR SFHA formerly protected from the 1 percent annual chance flood by a flood control system that was subsequently decertified; zone AR indicates that the former flood control system is being restored to provide protection from the 1 percent annual chance or greater flood Zone A99 Area to be protected from 1 percent annual chance flood by a federal flood protection system under construction; no base flood elevations determined Zone VE Area where waves and fast-moving water can cause extensive damage during the base flood event. Wave heights are larger than 3 feet. A detailed study has been done and BFEs have been calculated. Other Flood Areas Zone X (with color coding) Areas of 0.2 percent annual chance flood (i.e., 500-year flood); areas of 1 percent annual chance flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 1 percent annual chance flood Other Areas Zone X (with no shading) Areas determined to be outside the 0.2 percent annual chance floodplain Zone D Areas in which flood hazards are undetermined, but possible Source: FEMA Building improvement values and counts for those points were then extracted from the parcel/assessor’s data and summed for the unincorporated county and jurisdictions. Results of the overlay analysis area shown in Table 5-83 for the 1% annual chance flood and Table 5-84 for 0.2% annual chance flood. The jurisdictional annexes and Appendix E provide more detailed information based on property type. Property type refers to the land use of the parcel and includes agricultural, commercial, exempt, industrial, multi-residential, open space and residential. A loss estimate analysis was also performed based on depth damage functions developed by the Army Corp of Engineers and applied in FEMA’s BCA software. The loss curves depict the expected flood losses associated with the depth of flooding at a structure. Contents values were estimated as a percentage of building value based on their occupancy type, using FEMA/HAZUS estimated content replacement values. This includes 100% of the structure value for agricultural, commercial, exempt, and open space structures, 50% for multi-residential and residential structures and 150% for industrial structures. Building and contents values were totaled to obtain total exposure. There are different curves for structure and content losses. For the purposes of this planning level analysis, an average flood depth of 2 feet is assumed. A depth damage ratio of 25% was used for structural loss, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-240 based on the FEMA damage curves for a 2-foot flood. The results are shown in the loss estimate columns in Table 5-83 for the 1% annual chance flood and Table 5-84 for the 0.2% annual chance flood. It is important to note that there could be more than one structure or building on an improved parcel (i.e., a condo complex occupies one parcel but might have several structures). The end result is an inventory of the number and types of improved parcels subject to flooding. Results are presented by unincorporated county and incorporated jurisdictions. Detailed tables show counts of parcels by jurisdictions and land use type (agricultural, commercial, exempt, industrial, multi-residential, open space and residential) within each flood zone. This flood loss analysis does not account for business disruption, emergency services, environmental damages, or displacement costs, thus actual losses could exceed the estimate shown. Conversely, this analysis does not differentiate parcels that may have been developed since when the county and cities adopted floodplain regulations, which would be mitigated to the 1% annual chance flood if developed in accordance with regulations. Table 5-83 Count and Improved Value of Parcels in 1% Annual Chance Floodplain by Jurisdiction Jurisdiction Parcel Count Improved Value Content Value Total Value Loss Estimate % of Total Loss Arroyo Grande 196 $31,048,627 $15,699,806 $46,748,433 $11,687,108 3% Atascadero 140 $22,999,680 $14,166,934 $37,166,614 $9,291,654 2% City of San Luis Obispo 1,005 $526,573,627 $404,698,319 $931,271,946 $232,817,987 54% Grover Beach 33 $2,767,614 $1,759,398 $4,527,012 $1,131,753 0.3% Morro Bay 180 $35,416,008 $19,122,601 $54,538,609 $13,634,652 3% Paso Robles 126 $45,898,934 $22,691,477 $68,590,411 $17,147,603 4% Pismo Beach 112 $39,948,474 $18,243,435 $58,191,909 $14,547,977 3% Unincorporated 1,655 $341,104,689 $168,881,222 $509,985,911 $127,496,478 30% Total 3,447 $1,045,757,653 $665,263,190 $1,711,020,843 $427,755,211 100% Source: San Luis Obispo County’s Assessor’s Office; U.S. Census Bureau 2013-2017 estimates; National Flood Hazard Layer Effective date 05/16/2017, FEMA; GIS analysis All of San Luis Obispo County is at risk of being inundated by a 100-year flood event. The City of San Luis Obispo and unincorporated areas of the County are predominantly inundated by the 100-year floodplain and have the greatest percentages of total loss from a 100-year flood event., with 54% and 30% of the total potential loss respectively. While other jurisdictions are far less at risk during in a 100-year flood event, several jurisdictions including Paso Robles and Atascadero are at a greater risk of inundation in the event of a 500-year flood. While other coastal communities such as, Pismo Beach and Morro Bay may be more at risk of coastal flooding and coastal storms, refer to Coastal Storms/Coastal Erosion/Sea Level Rise section for details. Further discussion on the property types within the 100-year floodplain in the unincorporated areas can be found below. For specific analysis for each jurisdiction refer to the jurisdictional annexes and Appendix E. ----------------------------- ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-241 Table 5-84 Count and Improved Value of Parcels in 0.2% Annual Chance Floodplain by Jurisdiction Jurisdiction Parcel Count Improved Value Content Value Total Value Loss Estimate % of Total Loss Arroyo Grande 477 $89,177,181 $45,013,619 $134,190,800 $33,547,700 3% Atascadero 2,807 $510,278,898 $287,391,336 $797,670,234 $199,417,558 20% City of San Luis Obispo 1,475 $387,010,950 $221,600,543 $608,611,493 $152,152,873 15% Grover Beach 4 $315,959 $58,171 $374,130 $93,532 0.01% Morro Bay 264 $40,352,614 $20,050,949 $60,403,563 $15,100,891 2% Paso Robles 5,775 $1,244,000,280 $738,857,892 $1,982,858,172 $495,714,543 50% Pismo Beach 83 $13,858,571 $6,923,041 $20,781,612 $5,195,403 1% Unincorporated 996 $214,740,756 $108,866,662 $323,607,418 $80,901,854 8% TOTAL 11,881 $2,499,735,209 $1,428,762,211 $3,928,497,420 $982,124,355 100% Source: San Luis Obispo County’s Assessor’s Office; U.S. Census Bureau 2013-2017 estimates; National Flood Hazard Layer Effective date 05/16/2017, FEMA; Wood GIS analysis The percentage of total loss increases for all jurisdictions in a 500-year flood event. Paso Robles and Atascadero have the greatest increases of parcels being at risk of inundation in a 500-year flood. It should be noted that during 500-year flood event properties in the tables represent only those in a 0.2% Annual Chance flood hazard zone. A 500-year flood total loss would include the 100-year floodplain losses noted in Table 5-83 in addition to those located in the 500-year floodplain, as summarized in the table below. Table 5-85 San Luis Obispo County Flood Loss Estimates Flood Hazard Parcel Count Improved Value Content Value Total Value Loss Estimate 1% Annual Chance 3,447 $1,045,757,653 $665,263,190 $1,711,020,843 $421,996,605 0.2% Annual Chance 11,881 $2,499,735,209 $1,428,762,211 $3,928,497,420 $982,124,355 Total 15,328 $3,545,492,862 $2,094,025,401 $5,639,518,263 $1,404,120,960 Source: San Luis Obispo County’s Assessor’s Office; U.S. Census Bureau 2013-2017 estimates; National Flood Hazard Layer Effective date 05/16/2017, FEMA; Wood GIS analysis Based on this analysis, the San Luis Obispo County planning area has 3,447 parcels valued over $1 million in the 100-year floodplain. An additional 11,881 parcels valued at roughly $2.5 million fall within the 500- year floodplain. As a result, total structural exposure is approximately $3.5 billion. When factoring the content values within these areas in addition to the structures the total combined value of exposure is $5.6 billion. Table 5-86 and Table 5-87 below provides a detailed analysis that show the count and improved value of parcels that fall in a floodplain by property type for the 100- and 500-year annual chance flood zones. Additionally, these tables include information on loss estimates by flood based on guidance from FEMA. Based on this guidance, contents value is estimated at 50 percent of the improved value. Estimated losses assume that a flood is unlikely to cause complete destruction. Losses are related to a variety of factors, including flood depth, flood velocity, building type, and construction. Using FEMA’s recommendations, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-242 average damage is estimated to be 25 percent of the total building value. Refer to the annexes for these results specific to each jurisdiction. While there are several limitations to this model, it does allow for potential loss estimation. It should be noted that the model may have included structures in the floodplains that are elevated at or above the level of the base-flood elevation, which will likely mitigate flood damage. Also, it is important to remember that the assessed values are well below the actual market values. Thus, the actual value of assets at risk may be significantly higher than those included herein. Also, government/utilities properties are exempt and do not have improved values, thus undercounting the value of these property types. Table 5-86 Count and Improved Value of Parcels in 1% Annual Chance Floodplain by Property Type Property Type Parcel Count Improved Value Content Value Total Value Loss Estimate % of Total Loss Agricultural 89 $11,350,404 $11,350,404 $22,700,808 $5,675,202 1% Commercial 478 $367,413,965 $367,413,965 $734,827,930 $183,706,983 43% Government/Utilities 301 $253,272 -- $253,272 $63,318 0.01% Other/Exempt/Misc. 315 $61,003,405 -- $61,003,405 $15,250,851 4% Residential 1,467 $324,838,073 $162,419,037 $487,257,110 $121,814,277 28% Multi-Family Residential 449 $124,729,271 $62,364,636 $187,093,907 $46,773,477 11% Mobile/Manufactured Homes 116 $34,823,625 $17,411,813 $52,235,438 $13,058,859 3% Residential: Other 82 $64,200,376 $32,100,188 $96,300,564 $24,075,141 6% Industrial 19 $8,135,432 $12,203,148 $20,338,580 $5,084,645 1% Vacant 131 $49,009,830 -- $49,009,830 $12,252,458 3% TOTAL 3,447 $1,045,757,653 $665,263,190 $1,711,020,843 $427,755,211 100% Source: Wood GIS analysis on San Luis Obispo County’s Assessor’s Office/Parcel Quest data and FEMA NFHL ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-243 Table 5-87 Count and Improved Value of Parcels in 0.2% Annual Chance Floodplain by Property Type – Unincorporated San Luis Obispo Property Type Parcel Count Improved Value Content Value Total Value Loss Estimate % of Total Loss Agricultural 8 $5,755,995 $5,755,995 $11,511,990 $2,877,998 0.3% Commercial 978 $390,185,344 $390,185,344 $780,370,688 $195,092,672 20% Government/Utilities 215 $1,569,153 -- $1,569,153 $392,288 0.04% Other/Exempt/Misc. 400 $110,801,439 -- $110,801,439 $27,700,360 3% Residential 7,865 $1,336,764,814 $668,382,407 $2,005,147,221 $501,286,805 51% Multi-Family Residential 1,614 $372,095,045 $186,047,523 $558,142,568 $139,535,642 14% Mobile/Manufactured Homes 288 $35,754,816 $17,877,408 $53,632,224 $13,408,056 1% Residential: Other 358 $174,333,507 $87,166,754 $261,500,261 $65,375,065 7% Industrial 50 $48,897,854 $73,346,781 $122,244,635 $30,561,159 3% Vacant 105 $23,577,242 -- $23,577,242 $5,894,311 1% TOTAL 11,881 $2,499,735,209 $1,428,762,211 $3,928,497,420 $982,124,355 100% Source: Wood GIS analysis on San Luis Obispo County’s Assessor’s Office/Parcel Quest data and FEMA NFHL Insurance Coverage, Claims Paid, and Repetitive Losses Unincorporated San Luis Obispo County joined the National Flood Insurance Program (NFIP) in 1975. The County currently does not participate in the Community Rating System (CRS), although the City of San Luis Obispo and the City of Morro Bay are both CRS participants. Refer to those jurisdictional annexes for additional information. In the unincorporated County, there are 902 policies in force, of which there are 716 single family units, 34 2-4 family, 75 all other residential, and 77 nonresidential. There are 406 policies located in an A zone (256 in zone A01-30 & AE, 97 in zone A, 50 in AO, 3 AH). There are 2 policies located in zone V01-30 & VE zones. While the remaining 494 policies are split between standard B, C, & X zone (65) and preferred B, C, & X Zone (429). 420 policies are pre-FIRM, leaving 482 as post-FIRM structures. NFIP data indicates that there are 2,247 insurance policies in San Luis Obispo County representing $629,236,900 million of insurance coverage in force. Since 1978 there have been 342 paid losses, totaling $4,587,019 million. Table 5-88 provides more details on flood insurance policies for each individual jurisdiction. Repetitive Loss Properties FEMA insures properties against flooding losses through the NFIP. As part of the process to reduce or eliminate repetitive flooding to structures across the United States, FEMA has developed an official Repetitive Loss Strategy. The purpose behind the national strategy is to identify, catalog, and propose mitigation measure to reduce flood losses to the relatively few numbers of structures that absorb the majority of the premium dollars from the national flood insurance fund. A repetitive loss property is defined by FEMA as “a property for which two or more NFIP losses of at least $1,000 each have been paid within any 10-year period since 1978”. A repetitive loss property may or may not be currently insured by the NFIP. There are 28 repetitive loss buildings in the unincorporated County, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-244 9 of which are insured and a total of $1,122,171 million was paid out. Fourteen repetitive loss structures are located in A zone, with total payments equaling $602,136. There are twelve repetitive loss building is located in zone B, C, and X, with payments totaling $503,833. There is one target repetitive loss structure in the unincorporated County. There are no Severe Repetitive Loss properties, as defined by FEMA, anywhere in the County. Refer to the jurisdictional annexes for repetitive loss analysis for each participating jurisdiction. Table 5-88 San Luis Obispo County Flood Insurance Poliy Information Jurisdiction Policies Insurance in Force No. of Paid Losses Total Losses Paid Arroyo Grande 110 $30,278,600 19 $412,457 Atascadero 107 $13,507,500 18 $259,834 City of San Luis Obispo 736 $223,380,300 83 $456,370 Grover Beach 36 $9,940,700 2 $14,882 Morro Bay 175 $54,027,900 17 $243,005 Paso Robles 65 $18,517,800 5 $50,642 Pismo Beach 116 $37,758,200 7 $73,623 Unincorporated 902 $241,825,900 191 $3,076,206 Total 2,247 $629,236,900 342 $4,587,019 Source: FEMA National Flood Insurance Program Community Information System People The total number of residential properties in each floodplain was multiplied by the average household size of 2.51 persons for the County (ACS 2013-2017 estimates), and that total was multiplied by the County Occupancy Factor (95%) to estimate resident population. Based on this analysis, which accounts for residents only and not workers, there are 5,306 residents living in the 100-year flood zone throughout the County of San Luis Obispo. Of all study areas, the unincorporated county has the most residents living in the 1% annual chance flood area, followed by the City of San Luis Obispo. It should also be noted that this does not consider the student population living seasonally in the City of San Luis Obispo and these number may actually be greater with that additional populational accounted for. Table 5-89 below details population estimates by jurisdiction, followed by similar tables for the 500-year floodplain. Table 5-89 Population Living in 1% Annual Chance Flood Hazard Zone Jurisdiction Population Arroyo Grande 389 Atascadero 226 City of San Luis Obispo 1,448 Grover Beach 68 Morro Bay 294 Paso Robles 158 Pismo Beach 193 Unincorporated 2,530 Total 5,306 Source: Wood GIS analysis on San Luis Obispo County’s Assessor’s Office/Parcel Quest data and FEMA NFHL The same analysis was conducted for the 500-year floodplain, indicating that there are 25,414 residents living in the 500-year flood zone throughout San Luis Obispo County. The majority of people living in this ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-245 floodplain are residents of the Paso Robles, with over 12,000 people in the 500-year floodplain. This population distribution is shown in Table 5-90. Table 5-90 Population Living in 0.2% Annual Chance Flood Hazard Zone Jurisdiction Population Arroyo Grande 1,084 Atascadero 5,763 City of San Luis Obispo 3,313 Grover Beach 3 Morro Bay 615 Paso Robles 12,623 Pismo Beach 188 Unincorporated 1,825 Total 25,414 Source: Wood GIS analysis on San Luis Obispo County’s Assessor’s Office/Parcel Quest data and FEMA NFHL Social Vulnerability Flood hazards especially affect the socioeconomically vulnerable, those with disabilities, minorities, and housing or transportation vulnerable populations. This is because vulnerable populations may be unable to evacuate in a timely manner; may lose access to critical resources including life support technology or medicine due to flood damages; may be found in situations where their health conditions are exacerbated due to stagnant water-borne pathogens (or other communicable diseases); and may be more likely to drown, get injured, or suffer from hypothermia due to physical or mental impairments. Based on the SoVI data presented and discussed in subsection 4.4.1, some of the most socially vulnerable areas of the County are also vulnerable to flooding. This includes Oceano, Grover Beach, Paso Robles, and San Luis Obispo. A 500-year event in Paso Robles could have extensive societal impacts. Oceano and Grover Beach as well as Morro Bay, Los Osos and San Simeon may be of particular interest again due to their location along the coast, as they may see increased hazard risk due to combined exposure to tsunamis, coastal erosion, or sea level rise. Critical Facilities and Infrastructure Key support facilities and structures most necessary to withstand the impacts of, and response to, natural disasters are referred to as critical facilities. Examples of these critical facility types include utilities, transportation infrastructure, and emergency response and services facilities, given failures of component along major lifelines or even closures or inaccessibility to key emergency facilities could limit if not completely cut off transmission of commodities, essential services, and other potentially catastrophic repercussions. The following two tables summarize the number and types of critical facilities found to be at risk of flooding, based on flood hazard area in the first, and then by jurisdiction in the second table. These results were found by performing overlay analysis of the critical facilities and the flood hazard zone layers in GIS. Most of these facilities at risk are found in Paso Robles (37), though a few also in the unincorporated portions of the county and other jurisdictions with the exception of Grover Beach. Overall, a total of 89 critical facilities are found within flood hazard areas across the county; the majority (65) are located in the 500-Year or 0.2% annual chance flood hazard zone. Details on the specific properties at risk are found in Appendix E. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-246 Table 5-91 Critical Facilities in Flood Hazard Zones, by Jurisdiction Flood Hazard Zone Critical Facility Count 100-Year 23 500-Year 65 VE 1 Total 89 Source: San Luis Obispo County Planning & Building Dept/GIS, HIFLD, FEMA’s NFHL, San Luis Obispo County Community Services Districts, Wood GIS analysis Table 5-92 Critical Facilities in Flood Hazard Zones, by Flood Hazard Area Jurisdiction Critical Facility Count Arroyo Grande 3 Atascadero 13 City of San Luis Obispo 13 Morro Bay 8 Paso Robles 37 Pismo Beach 1 Unincorporated 14 Total 89 Source: San Luis Obispo County Planning & Building Dept/GIS, HIFLD, FEMA’s NFHL, San Luis Obispo County Community Services Districts, Wood GIS analysis Economy Flooding can have a major economic impact on the economy. Based on the flood loss analysis, there are 478 commercial structures worth an estimated $700 M in total value directly at risk to flooding in the 1% annual chance zone. Based on the loss analysis (described further above) this could result in approximately $180M in direct losses. This does not account for other indirect losses such as business interruption, lost wages and other downtime costs. Effects on the agriculture economy can be devastating. Flooding can damage crops and livestock. In addition to the obvious impacts on crops and animals, flooding can have deleterious effects on soil and the ability to reinvigorate the agricultural activities impacted once the flood waters recede. Damage to water resources such as underground irrigation systems, water storage reservoirs, springs and other natural water bodies could have a serious effect upon agriculture operations. Historic, Cultural, and Natural Resources San Luis Obispo County has significant historic, cultural, and natural resources located throughout the County as previously described. GIS analysis indicates that a total of thirty-eight (38) historic properties are potentially at risk to flooding. Of those thirty-eight historic properties, sixteen (16) are at risk of a 100- year flood event and twenty-one (21) historic properties are at risk of inundation in a 500-year flood. Details on the specific properties at risk are found in Appendix E. Natural areas within the floodplain often benefit from periodic flooding as a naturally recurring phenomenon. These natural areas often reduce flood impacts by allowing absorption and infiltration of floodwaters. Natural resources are generally resistant to flooding except where natural landscapes and soil compositions have been altered for human development or after periods of previous disasters such as ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-247 drought and fire. Wetlands, for example, exist because of natural flooding incidents. Areas that are no longer wetlands may suffer from oversaturation of water, as will areas that are particularly impacted by drought. Areas recently suffering from wildfire damage may erode because of flooding, which can permanently alter an ecological system. Future Development Flooding and floodplain management are significant issues for San Luis Obispo County. The potential or likelihood of a flood event in the county increases with the annual onset of heavy rains in winter and spring months. Much of the historical growth in the problem areas connected with flooding and stormwater runoff include erosion, sedimentation, degradation of water quality, losses of environmental resources, and certain health hazards. Future annexations of unincorporated areas could significantly add to the number of flood-prone structures in San Luis Obispo County. For NFIP participating communities, floodplain management practices implemented through local floodplain management ordinances should mitigate the flood risk to new development in floodplains. The development trend in the San Luis Obispo County planning area is steady, significant growth. Much of this growth is occurring in the urban and coastal areas, which can increase stormwater runoff. The 2018 Caltrans Economic Forecast at the county-level for all 58 counties in California for 2018-2050, projects that San Luis Obispo County’s population will continue to increase by 0.4 annually through 2023, 97 percent being from net migration (Caltrans 2018). The report also notes that with this growth in population and the County’s large amount of buildable land, housing development will likely be spread out rather than developments with higher density. Such growth will consume previously undeveloped acres, and the increase in impervious surfaces could affect existing drainage and flood control facilities. The potential for flooding may increase as stormwater is channelized due to land development. Such changes can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. Floodplain modeling and master planning should be based on buildout land use to ensure that all new development remains safe from future flooding. While local floodplain management, stormwater management, and water quality regulations and policies address these changes on a site-by-site basis, their cumulative effects can have a negative impact on the floodplain. The County of San Luis Obispo’s Local floodplain management ordinance require that new construction be built with the lowest floor elevated a minimum of one foot above the base flood (100-year) elevation. New development that adheres to the elevation requirements in addition to other requirements for maintaining elevation certificates and implementing stormwater program elements and erosion or sediment controls for all new development in the floodplain should help protect development from 100- year floods. For this plan, an additional GIS overlay analysis of building construction permits for residential and commercial properties was performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties may be constructed, or may have upgrades done, within flood hazard zones (see the table right below). More detail on the specific types of permits granted, particularly the kind of work class and case type for each permit group, can be found under the Asset Summary section of this plan. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-248 Table 5-93 Building Permits Submitted within Flood Hazard Zones from 2014-2019 Flood Event Work Class Case Type Work Class Type Total 100-Year Conditional Use Permit Land Use 24 Minor Use Permit Land Use 44 New Structure PMTC - Commercial Permit 40 PMTR - Residential Permit 87 TOTAL 195 500-Year Conditional Use Permit Land Use 3 Minor Use Permit Land Use 58 New Structure PMTC - Commercial Permit 10 PMTR - Residential Permit 40 TOTAL 111 VE Minor Use Permit Land Use 1 TOTAL 1 GRAND TOTAL 307 Source: San Luis Obispo County Planning & Building Department, FEMA’s NFHL, Wood GIS analysis Risk Summary • Overall significance of the flood hazard is Medium. • Countywide there are 15,328 structures at risk worth $3.5B, with a loss estimate of $5.6B • The City of San Luis Obispo accounts for 54% of the total losses in the 100-year floodplain. • Commercial structures account for 43% of total losses in the 100-year floodplain, with a loss estimate of $183M • Paso Robles accounts for 50% of the total losses in the 500-year floodplain. • Residential structures account for 51% of total losses in the 500-year floodplain. • Countywide approximately 5,306 persons live in the 100-year floodplain, of which 2,530 are in the unincorporated areas • There are 25,414 persons within the 500-year floodplain, of which 12,623 people are within the City of Paso Robles. • A total of 89 critical facilities are found in 100-year (23 facilities), 500-year (65 facilities), or VE/coastal (1) flood zones in the county. Most of them are in Paso Robles, with 13 or less in each of the other incorporated jurisdictions as well as the unincorporated lands. • Related hazards: Adverse weather: Thunderstorm/Heavy Rain, Coastal Storm/Coastal Erosion/Sea Level Rise, Wildfire, Landslide and Debris Flow. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-249 Table 5-94 Flood Hazard Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Significant Likely Critical Medium City of Arroyo Grande Significant Highly Likely Limited Medium City of Atascadero Significant Occasional Critical Medium City of Grover Beach Limited Occasional Limited Low City of Morro Bay Extensive Highly Likely Critical High City of Paso Robles Significant Likely Limited High City of Pismo Beach Significant Likely Limited Medium City of San Luis Obispo Limited Occasional Limited Medium Avila Beach CSD Significant Highly Likely Limited Medium Ground Squirrel Hollow CSD Limited Occasional Limited Low Heritage Ranch CSD Extensive Likely Critical High Los Osos CSD Significant Likely Limited Low Nipomo CSD Limited Occasional Limited Low San Miguel CSD Limited Occasional Limited Medium San Simeon CSD Limited Likely Negligible Low Templeton CSD Limited Likely Limited Low Cayucos Sanitary District Significant Likely Critical High Port San Luis Harbor District Limited Highly Likely Limited Medium San Luis Obispo FCWCD Significant Likely Critical Medium South San Luis Obispo Sanitary District Significant Highly Likely Limited Medium ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-250 5.3.12 Landslides and Debris Flow Hazard/Problem Definition A landslide is a geologic hazard where the force of gravity combines with other factors to cause earth material to move or slide down an incline. Some landslides move slowly and cause damage gradually, whereas others move so rapidly that they can destroy property and take lives suddenly and unexpectedly. Slopes with the greatest potential for sliding are between 34 degrees and 37 degrees. Although steep slopes are commonly present where landslides occur, it is not necessary for the slopes to be long. Debris flows are a mixture of rock fragments, soil, vegetation, water and, in some cases, entrained air that flows downhill as a fluid. Debris flows can range in consistency from that of freshly mixed concrete to running water. Debris flows can be further classified as mudflows and earth flows depending on the ratio of water to soil and rock debris. Landslides, rockslides, and debris flows occur continuously on all slopes; some processes act very slowly, while others occur very suddenly, often with disastrous results. Landslide and debris flow problems can be caused by land mismanagement, particularly in mountain, canyon, and coastal regions. In areas burned by forest and brush fires, a lower threshold of precipitation may initiate landslides and debris flows. As human populations expand over more of the land surface, these processes become an increasing concern. There are predictable relationships between local geology and landslides, rockslides, and debris flows. The down-slope movement of earth material, either as a landslide, debris flow, mudslide, or rockslide, is part of the continuous, natural process of erosion. This process, however, can be influenced by a variety of causes that change the stability of the slope. Slope instability may result from natural processes, such as the erosion of the toe of a slope by a stream, or by ground shaking caused by an earthquake. Slopes can also be modified artificially by grading, or by the addition of water or structures to a slope. Development that occurs on a slope can substantially increase the frequency and extent of potential slope stability hazards. Knowledge of these relationships can improve planning and reduce vulnerability. Slope stability is dependent on many factors and their interrelationships, including rock type, moisture content, slope steepness, and natural or man-made undercutting. Geographic Area In San Luis Obispo County, there are several geologic formations commonly associated with slope stability problems. The data presented on the following presents a summary of landslide hazard potential. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-251 Figure 5-74 Landslide Potential PACIFIC OCEAN Landslide Potential -Very High High Moderate Low -+--+ Railroads --Highwa y ---Freewa y r :::::1 Cities ,,---7 Counties [ ____ I Map compiled 3/2019 ; Morro intended for planning purposes only. Data Source : San Lu is Obispo County, US Census TIGER Database , CA Open Data Porta l ••• I I Monterey I I Tulare Kings I I I 7:",'3J;Ee<"=S==ea:c"i\-,===----...................... _ ________J ,_~~---- Kern Santa Barbara 0 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-252 The geologic formations commonly associated with slope stability problems in San Luis Obispo County, include the Franciscan, Rincon, Toro, and Monterey formations. Of these, the Franciscan is the most well- known formation known for slope instability. Numerous landslides within the Franciscan complex are observable along the Highway 1 corridor from San Luis Obispo to San Simeon. Numerous landslides have also been mapped in the Franciscan and Toro formations along Highway 101 on the Cuesta Grade. Landslides in the Franciscan formation have impacted residences, roadway facilities, pipelines, and other infrastructure in the county. The Rincon and Toro formations have a similar geologic history of land sliding but are generally not as widespread as the Franciscan. An active landslide has also been identified in the vicinity of Harbor Terrace near Port San Luis Harbor west of Avila Beach. Geologic formations located in San Luis Obispo County that present a moderate slope stability hazard potential include the Quaternary bedrock units such as the Paso Robles Formation and formations of equivalent age and composition. The susceptibility of areas underlain by these formations to slope stability impacts will vary based on a variety of site-specific factors, such as slope, the orientation of bedding planes, rainfall, characteristics of the overlying soil, and the type and extent of proposed slope modifications. In some areas, slopes may be stable in a natural condition, but alterations to the hillsides to accommodate urban development may cause unstable conditions that could adversely affect future development. Prior to the initiation of new development that could be adversely affected by slope movement, site specific evaluations are necessary to determine the hazard potential and to identify engineering design methods to minimize the risk of landslide-related damage. San Luis Obispo County: Numerous large landslides are also mapped in the steep mountainous terrain of the Santa Lucia, La Panza and Caliente Mountain ranges and many canyons. Landslides of this type have been mapped in nearly all of the formations and are generally related to steep slopes, adverse geologic structure, weak or weathered formations, faulting, and wet slopes. To date, only limited geologic mapping has been performed to evaluate the presence of landslides in the hillside areas of the County. Most of the geologic studies to date have focused on large scale geologic structure, faulting, or other geologic issues and did not specifically evaluate land sliding. A significant amount of additional studies needs to be performed to identify and evaluate landslides to help reduce the potential for long term damage related to slope instability. Sections 22/23.05.020 of the San Luis Obispo County Land Use Ordinance and Coastal Zone Land Use Ordinance, Titles 22 and 23 of the County Code, contain the county’s grading ordinance. This ordinance outlines specific requirements for grading permits, procedures for reviewing and approving grading permits, inspection requirements for completed grading projects, and erosion and drainage requirements. Section 22/ 23.07.080 defines general requirements for identifying Geologic Study Areas (GSA) that would require a geology report to address landslide hazards. Arroyo Grande: A majority of the existing development in Arroyo Grande is located on gently inclined alluvial valley sediments and the hilly terrain north of Branch Street. The potential for slope stability hazards in valley areas is low to very low. The potential slope instability is greatest in the hilly areas of the City. The potential for slope instability in the sloping terrain can mostly be mitigated by applying building code requirements that provide minimum requirements for building construction and grading on sloping ground as those areas are not known to be underlain by large landslide features or unstable formations. However, there are relatively steep hillsides and canyons near the City, and as development moves into those areas, there could be greater potential for slope stability related concerns. A thorough ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-253 geologic/geotechnical study should be prepared prior to development for projects planned in those areas. Title 7, Chapter 1, of the Arroyo Grande Municipal Code provides development standards adopted by the City pertaining to excavation, grading, erosion, and sediment control. This section specifies performance standards and other requirements intended to protect public health and safety and minimize hazards from excavation and filling activities. Atascadero: Development in Atascadero generally has occurred in two areas: along the alluvial valley of the Salinas River and Highway 101, and in the relatively steeply sloping terrain of the Santa Lucia Mountains west of Highway 101. The primary bedrock geologic units exposed in the area include the Tertiary-age Santa Margarita, Vaqueros, and Monterey formations, and Cretaceous-age unnamed, Franciscan, Toro, and Atascadero formations. The potential for slope instability in the alluvial valleys is low to moderate because of fairly gentle slopes. Developments in steeper hillside areas have a known history of slope instability, and a moderate to very high hazard potential for slope instability problems. Localized undercutting by streams or development could cause instability. Appropriate geologic studies should be performed prior to development to evaluate this increased level of risk. The Franciscan and upper Cretaceous formations are exposed along the eastern flank of the Santa Lucia Mountains. These formations are the predominant geologic unit in the hilly southwestern portion of the City. In this area, 50 separate landslides have been mapped, encompassing 268 acres. The City has recently made repairs in this area to roadways damaged from land sliding. Although some of the mapped landslides may now be relatively stable, the concentration of old and recent landslides is indicative of relatively unstable slope conditions. This area is considered to have a high to very high potential for slope instability. Thorough geologic/geotechnical study should be prepared prior to development for projects planned in those areas. Sections 9-4.138 through 9-4.146 of the Atascadero Zoning Ordinance provide development standards adopted by the City pertaining to excavation, grading, erosion, and sediment control. These sections specify performance standards and other requirements intended to protect public health and safety and minimize hazards from excavation and filling activities. In Atascadero, any grading on slopes at or exceeding ten percent must undergo environmental review pursuant to the California Environmental Quality Act (CEQA). Grover Beach: Grover Beach is characterized by fairly gently inclined slopes with gradients of less than 50 percent on slopes consisting of older alluvium and late Pleistocene dune sands. The potential for slope stability concerns is low. Locally, there may be a potential for shallow slope failures in loose dune sands on areas of steep terrain. The potential for slope instability in the sloping terrain can mostly be mitigated by applying building code requirements that provide minimum requirements for building construction and grading on sloping ground as these areas are not known to be underlain by large landslide features or notoriously unstable formations. Sections 8400 through 8423 of the Grover Beach Municipal Code provides for the development standards adopted by the City pertaining to excavation, grading, erosion, and sediment control. These sections specify performance standards and other requirements intended to protect public health and safety and minimize hazards from excavation and filling activities. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-254 Morro Bay: Numerous studies have documented unstable, landslide prone slopes in the Morro Bay area east of Highway 1 and north of Highway 41. Many of the landslides mapped in the area are associated with the Franciscan mélange. The landslide hazards that have impacted residential development and lifeline facilities are most prevalent on west-facing slopes. Although some of the mapped landslides may now be relatively stable, the concentration of old and recent landslides is indicative of relatively unstable slope conditions. This area is considered to have a high to very high potential for slope instability. Thorough geologic/geotechnical study should be prepared prior to development for projects planned in those areas. General Plan Policies S-6.1 and S-7.1 and Coastal Plan Policies 9.04 and 9.07 require that geology and soils reports be prepared to identify and evaluate potential adverse conditions from grading activities in specific areas of the City. Paso Robles: A majority of the existing development in Paso Robles is located in areas of gently rolling hills with slope inclinations between 50 percent to 20 percent or less. The primary bedrock geologic unit in the area is the Paso Robles Formation. However, the Paso Robles Formation contains localized areas of relatively weak clay units, which are susceptible to small- to large-sized landslides. These landslides are not well mapped regionally but are often identified by site-specific studies. The Salinas River flood plain is also an area of extensive development in the Paso Robles area. Because of the fairly gentle slopes, the potential for slope stability concerns in this area is generally low. The layered bedrock is folded and faulted and is subject to localized undercutting by streams or development. If the bedding becomes laterally unsupported, there is an increased potential for instability. Appropriate geologic studies should be performed prior to development to evaluate this increased level of risk. Title 20 of the Paso Robles Municipal Code provides development standards that have been adopted by the City pertaining to excavation, grading, erosion, and sediment control. These sections specify performance standards and other requirements intended to protect public health and safety and minimize hazards from excavation and filling activities. Pismo Beach: The potential for landslides is present on the hill sides to the north of highway 101 and along the Price Canyon corridor. The potential slope instability is greatest on the west facing slopes directly adjacent to the freeway and Price Canyon Road. The potential for slope instability in the sloping terrain can mostly be mitigated by applying building code requirements that provide minimum requirements for building construction and grading on sloping ground, as these areas are not known to be underlain by large landslide features or notoriously unstable formations. The City of Pismo Beach’s Safety Element provides information on their policies related to land areas subject to hazards associated with steep slopes. City of San Luis Obispo: The majority of the development in San Luis Obispo is in the valley area with a low to very low potential for slope instability. However, the hillside areas to the east, north and west of the City, as well as along the flanks of the Morros, are underlain by the Franciscan mélange, which is a source of significant slope instability. Areas of the City with steep topography and geologic formations prone to slope stability problems are depicted on Map 4. Because of the past slope stability related problems, a thorough geologic/ geotechnical study should be prepared prior to development for projects planned in those areas. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-255 Surrounding area: Landslides in neighboring counties can have indirect consequences in San Luis Obispo County, notably in Monterrey County to the north in the vicinity of Big Sur and Highway 1. Extent (Magnitude/Severity) The extent of landslides and debris flow events within the county range from negligible to significant. Landslides and rockslides can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage. Disrupted transportation routes occur occasionally, usually during heavy rain storms, and cause considerable inconvenience and result in economic impacts. The potential for complete destruction of buildings and death and injury from landslides and debris flow also exists. Previous Occurrences An active landslide has also been identified in the vicinity of Harbor Terrace near Port San Luis Harbor west of Avila Beach (2014 San Luis Obispo HMP). In May 2017 the Mud Creek Slide buried a quarter mile section of scenic Highway 1 approximately nine miles north of the San Luis Obispo- Monterey County line. Caltrans estimates that over one million tons of rock and dirt fell during the slide, which is actually a combination of five slides. The affected section of Highway 1 was covered by a layer of dirt and rock about 35 to 40 feet deep. The section of Highway 1 closed by the slide re-opened in July 2018 (CA SHMP 2018). In 2016 the Chimney Fire burned in San Luis Obispo County. Heavy rains in January 2017 lead to debris flows into Nacimiento Reservoir; Nacimiento Reservoir water is the only source of potable water for Heritage Ranch CSD (Heritage Ranch HM Planning Workbook 2019). 2/20/1996 - 4 to 6 inches of rain in the San Luis Obispo Co. Mountains caused Urban and small stream flooding and associated mudslides in the steep terrain and along Hwy 1 and 101 (NCEI). The HMPC provided the following comments on previous landslide and debris flow incidents: • Avila Beach Drive has been a problem area. The County has done repairs and improvements. • Fremont Hall, a dorm on Cal Poly’s campus remained closed for the 2018-2019 school years due to a potentially hazardous hillside behind the dorm. The dorm had previously been closed since February 2017 after heavy rainfall caused a mudslide that threatened the building (San Luis Obispo Tribune, 2017). • The Cambria Community Healthcare District facility in Cambria was impacted by a landslide. • County roads along Santa Rosa Creek are considered at risk by the County. • Highway 41 between Morro Bay and Atascadero has been closed periodically due to rockslides. • Impacts to high mountain roads in Poso and Lopez area has affected fire response as well as in Road 166, City of Atascadero and San Simeon • Areas near the Hearst Castle have also seen movement. Probability of Future Occurrences Based on historical data and given the presence of landslide-susceptible geology and steep slopes in the planning area, landslides hazards are likely to continue on an annual basis, with damaging landslides less frequently. Landslides are usually a cascading effect of severe weather. The probability for more severe ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-256 and damaging landslides increases during El Nino years or severe winter storms. The potential for debris flows dramatically increases following a wildfire. Climate Change Considerations Landslides can result from intense rainfall and runoff events. Projected climate change-associated variance in rainfall events may result in more high-intensity events, which may increase landslide frequency. In addition, the increased potential of wildfire occurrence also escalates the risk of landslide and debris flows in the period following a fire, when slopes lack vegetation to stabilize soils and burned soil surfaces create more rainfall runoff. As climate change affects the length of the wildfire season, it is possible that a higher frequency of large fires may occur into late fall, when conditions remain dry, and then be followed immediately by intense rains early in the winter, as occurred with the Thomas Fire in December 2017 and subsequent Montecito and Carpinteria debris flows in January 2018 in adjacent Santa Barbara County (CA SHMP 2018). Vulnerability General Property Landslides directly damage engineered structures in two general ways: 1) disruption of structural foundations caused by differential movement and deformation of the ground upon which the structure sits, and 2) physical impact of debris moving downslope against structures located in the travel path. During the 2019 update of this plan, a GIS analysis of exposure to landslide hazard areas was performed. GIS analysis indicates approximately $4.9 billion of property improvements exposed, which takes into account improved values of properties; $67 million of that value is within Very High potential areas. Table 5-95 summarizes landslide exposure by jurisdiction in the Moderate and above categories, based on an intersect of improved parcel center with landslide hazard areas. Based on this analysis there is a total of 17,724 developed properties potentially within landslide hazard areas rated Moderate to Very High; 301 of these properties are in Very High potential hazard areas and 8,508 in high potential areas. The greatest exposure of general property summarized in High and Very High in Table 5-96 is generally with residential properties, though the number of government/utilities properties in High and Very High landslide potential areas is also significant; note that the lack of replacement value for these parcels is due to these properties being exempt for tax assessment purposes. More specifics on the developed parcels exposed are included in Appendix E, including additional details on property types aggregated by landslide potential and jurisdiction. The unincorporated areas and the cities of Atascadero, Morro Bay, Pismo Beach and San Luis Obispo have the most properties in High or Very High landslide potential areas. There is a high level of uncertainty as to the actual risk to these exposed parcels, thus a more specific loss estimation is not provided. A more detailed, site specific analysis would be needed to assess actual risk within the identified parcels. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-257 Figure 5-75 Improved Parcels Within High or Very High Landslide Potential Areas PACIFIC OCEAN Pa rcels Within La ndsl ide Pote ntia l Areas • Very High o High Landslide Po tential -Very High High Waterways Lakes -+--+ Railroads Highway Free way D eities ••• Map compiled 3/2019 ; intended for plann ing purposes only. Data Source : Sa n Luis Obispo County, US Census T IGER Database , CA Ope n Data Portal 0 I Monterey i Kings i Tulare I I I ----------------------- Po.rnCreek Kern s;f,;,})"'10 o::>g OoO:;,~_-/J?~ Oo 00 :.f11i,r.,. o~ oo~~ioc -.;-,!' ~· 0 0 0 •o . ••J(°o, 0 o o O ~:::~~~~ oo,,0 ~I ~]~ o o o goo o o B o o o o o o o.• ..o o o o (}~0scg1w ~-;,wg~.11ra;L6~e0 ~ 0 0 •"-~1'0 °0 co ooi\ 000000 Tak~• 0 0 °0 00 o o O o o o<>o e 0000 °°oeoo0 PJ oo o o 0 ooo C Cl o o • o o ci: ~o o ~ o ~ oo o o o Soda Lc,ke ~C?i .~~ o,i:•o 00 o(/l~i!~0t 0;:"oo\00 oyo~Grande O O ~•}i.?0 o o o 0 o0 ~ {) , :i~ ◊ O ¾ O fl?~_ o o0 :) 0 O ovce O ,r O 0 o o 0 o O 0 eservoir ) Santa Barbara Ventu ra 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-258 Table 5-95 Landslide Hazard Exposure – General Property Summary by Jurisdiction Jurisdiction Property Count - Moderate Improved Value- Moderate Property Count - High Improved Value - High Property Count - Very High Improved Value - Very High Arroyo Grande 509 $171,390,279 3 $254,572 - Atascadero 1,612 $410,440,385 469 $136,106,517 25 $5,427,868 City of San Luis Obispo 721 $230,452,509 174 $70,603,528 1 -- Grover Beach 46 $9,804,432 -- -- -- -- Morro Bay 378 $95,102,718 310 $60,562,714 14 $4,815,420 Paso Robles 849 $226,286,416 12 $3,171,310 -- -- Pismo Beach 740 $248,322,889 303 $133,697,143 -- -- Unincorporated 7,768 $2,336,482,101 3,529 $788,977,779 261 $57,479,097 TOTAL 12,623 $3,728,281,729 4,800 $1,193,373,563 301 $67,722,385 Source: Parcel analysis by Wood Table 5-96 Landslide Hazard Exposure –Property Summary by Type in High and Very High Potential Property Type Property Count - High Improved Value - High Property Count – Very High Improved Value- Very High Agricultural 113 $40,457,302 8 $2,175,923 Commercial 4 $1,105,687 1 $1,881,463 Government/Utilities 759 - 42 -- Industrial 1 $383,096 21 $2,011,942 Residential 3,162 $1,029,473,446 213 $60,349,742 Mobile/Manufact. Homes 209 $26,130,440 5 $400,501 Multi-Family Residential 102 $19,767,227 2 $514,606 Residential: Other 17 $45,303,597 - - Vacant 251 $28,144,278 9 $388,208 Total 4,800 $1,193,373,563 301 $67,722,385 Source: Parcel analysis by Wood People People could be susceptible if they are caught in a landslide or debris flow, potentially leading to injury or death. There is also a danger to drivers operating vehicles, as rocks and debris can strike vehicles passing through the hazard area or cause dangerous shifts in roadways. Social Vulnerability In general, the areas for high landslide potential fall outside of the municipalities and census designated places, thus it is difficult to pinpoint specific areas of social vulnerability. Census tract data indicates possible coincidence of high and moderate landslide potential west of Paso Robles. Since landslide occurrence can be linked to earthquake and general seismic activity, it is possible that landslide and debris flow hazards may cause similar risks as those tied to earthquake (e.g. inability for disabled or vulnerable populations to evacuate in a timely manner, inability to communicate critical information to ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-259 those who may not speak English well, potential for populations to lose access to key resources such as life support technology or medicine). Critical Facilities and Infrastructure In addition to buildings, utilities and transportation structures are vulnerable to the impact and ground deformation caused by slope failures. They present a particular vulnerability because of their geographic extent and susceptibility to physical distress. Lifelines are generally linear structures that, because of their geographic extent, have a greater chance of being affected by ground failure due to greater hazard exposure. Extension, bending, and compression caused by ground deformation can break lifelines. Failure of any component along the lifeline can result in failure to deliver service over a large region. Once broken, transmission of the commodity through the lifeline ceases, which can have catastrophic repercussions down the line: loss of power to critical facilities such as hospitals, impaired disposal of sewage, contamination of water supplies, disruption of all forms of transportation, release of flammable fuels, and so on. Therefore, the overall impact of lifeline failures, including secondary failure of systems that depend on lifelines, can be much greater than the impact of individual building failures. The following two tables summarize the results of the GIS analysis, which indicate the types of critical facilities that are located in areas of landslide potential. Table 5-97 contains the number of critical facilities found within all landslide potential areas by jurisdiction. Table 5-98 summarizes the same information for all jurisdictions but broken up by landslide potential area. An analysis of bridges within areas of landslide potential areas is also summarized under Table 5-99. The majority of these facilities are communications facilities (microwave, cellular, AM and FM transmission towers). More specifics on the actual facilities can be referenced in Appendix E. Table 5-97 Critical Facilities within Landslide Potential Zones, by Jurisdiction Jurisdiction Total Facilities Atascadero 5 Morro Bay 1 Paso Robles 11 Pismo Beach 4 San Luis Obispo 13 Unincorporated 437 TOTAL 471 Source: San Luis Obispo County Planning & Building Department/GIS, HIFLD, San Luis Obispo County Community Services Districts, Wood GIS analysis Table 5-98 Critical Facilities within Landslide Potential Areas, by Potential Category Landslide Potential Total Facilities Moderate Landslide Potential 234 High Landslide Susceptibility 227 Very High Landslide Potential 10 TOTAL 471 Source: San Luis Obispo County Planning & Building Department/GIS, HIFLD, San Luis Obispo County Community Services Districts, Wood GIS analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-260 Table 5-99 Landslide Exposure – Bridges Landslide Potential Total Bridges Moderate 33 High 38 Very High 2 TOTAL 73 Source: Wood Analysis on National Bridge Inventory data, 2018 Economy Economic impacts typically center around transportation routes temporarily closed by debris flow or landslide activity. These roads may be used to transport goods across the county or provide access by visitors and tourists. Depending on the amount of damage, the road may simply need to be cleaned off, or may need some level of reconstruction Historic, Cultural, and Natural Resources As primarily a natural process, landslides and debris flows can have varying impacts to the natural environment; debris flows have the potential to permanently alter the natural landscape. GIS analysis indicates that 18 historic properties are potentially at risk to landslides; six are in high hazard and 12 are in moderate hazard potential areas. Specific property details can be referenced in Appendix E. Future Development The severity of landslide problems is directly related to the extent of human activity in hazard areas. Human activities such as property development and road construction can also exacerbate the occurrence of landslides. Future development should take place carefully to prevent landslide damage to property or people. Adverse effects can be mitigated by early recognition and avoiding incompatible land uses in these areas or by corrective engineering. Improving mapping and information on landslide hazards and incorporating this information into the development review process could prevent siting of structures and infrastructure in identified hazard areas. The county’s grading ordinance and Section 22/ 23.07.080 defines general requirements for identifying Geologic Study Areas (GSA) that require a geology report to address landslide hazards should help mitigate risk to future development. A GIS overlay analysis of building construction permits for residential and commercial properties was additionally performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties may be constructed, or may have upgrades completed, in landslide potential areas (see Table 5-100). More detail on the specific types of permits granted, particularly the kind of work class and case type for each permit group, is contained in Table 5-101. Table 5-100 Building Permits Submitted in Landslide Potential Areas from 2014-2019 Landslide Potential Total Building Permits Moderate 871 High 528 Very High 29 TOTAL 1,428 Source: San Luis Obispo County Planning & Building Department, Wood GIS analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-261 Table 5-101 Details on Building Permits Granted in Landslide Potential Areas from 2014-2019 Landslide Potential Work Class Case Type Work Class Type Total Moderate Conditional Use Permit Land Use 40 Minor Use Permit Land Use 101 New Structure PMTC - Commercial Permit 185 PMTR - Residential Permit 545 TOTAL 871 High Conditional Use Permit Land Use 49 Minor Use Permit Land Use 69 New Structure PMTC - Commercial Permit 195 New Structure PMTR - Residential Permit 215 TOTAL 528 Very High Conditional Use Permit Land Use 12 Minor Use Permit Land Use 5 New Structure PMTC - Commercial Permit 3 PMTR - Residential Permit 9 TOTAL 29 GRAND TOTAL 1,428 Source: San Luis Obispo County Planning & Building Department, Wood GIS analysis Risk Summary The overall significance of landslides and debris flows in San Luis Obispo County is Medium. These events are recurring in nature and could disrupt critical elements of the county’s infrastructure. • The geologic formations commonly associated with slope stability problems in San Luis Obispo County, include the Franciscan, Rincon, Toro, and Monterey formations. Of these, the Franciscan is the most well-known formation known for slope instability. • Numerous landslides within the Franciscan complex are observable along the Highway 1 corridor from San Luis Obispo to San Simeon. • Effects on people: People and property are at risk from landslides and debris flow in San Luis Obispo County. For the most part, past incidents have not resulted in significant injuries or loss of life. • Effects on property: Property loss is rare but is usually significant when it occurs; a high number of structures are built on or near landslide potential areas based on GIS analysis. • Effects on economy: Landslides and debris flows in adjacent counties can disrupt major transportation corridors along Highway 1, affecting the local tourist economy. • Effects on critical facilities and infrastructure: Landslides and debris flows can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage. Disrupted transportation routes occur occasionally, usually during heavy rain storms, and cause considerable inconvenience. Based on GIS analysis, there are 10 critical facilities found within very high landslide susceptibility zones, 227 facilities in high landslide susceptibility zones, and 234 in moderate landslide zones, for a total of 471 facilities at risk of this hazard. The majority are in the ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-262 unincorporated portions of the county (437), with 13 in San Luis Obispo City, 11 in Paso Robles, 5 in Atascadero, 4 in Pismo Beach, and 1 in Morro Bay. • Related Hazards: Earthquake, Coastal Storm/Coastal Erosion/Sea Level Rise, Adverse Weather, Wildfire, Table 5-102 Landslide and Debris Flow Hazards Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Significant Likely Critical Medium City of Arroyo Grande Limited Unlikely Limited Low City of Atascadero Significant Likely Significant Medium City of Grover Beach Limited Unlikely Limited Low City of Morro Bay Limited Occasional Limited Medium City of Paso Robles Limited Likely Limited High City of Pismo Beach Significant Likely Limited Medium City of San Luis Obispo Limited Occasional Limited Low Avila Beach CSD Significant Occasional Limited Medium Ground Squirrel Hollow CSD Limited Highly Likely Negligible Medium Heritage Ranch CSD Extensive Likely Negligible High Los Osos CSD Limited Occasional Limited Low Nipomo CSD Limited Unlikely Limited Low San Miguel CSD Limited Occasional Limited Medium San Simeon CSD Significant Likely Catastrophic Medium Templeton CSD Limited Unlikely Limited Low Cayucos Sanitary District Limited Occasional Limited Medium Port San Luis Harbor District Significant Highly Likely Critical Medium San Luis Obispo FCWCD Significant Likely Critical Medium South San Luis Obispo Sanitary District Limited Unlikely Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-263 5.3.13 Soil Hazards: Land Subsidence Hazard/Problem Description Land subsidence is defined as the vertical sinking of the land over natural or manmade underground voids. Subsidence is common in several areas of California, usually as a result of groundwater pumping, peat loss, or oil and gas extraction. Fluctuations in the level of underground water caused by pumping or by injecting fluids into the earth can initiate sinking to fill the empty space previously occupied by water or soluble minerals. Weight, including surface developments such as roads, reservoirs, and buildings, and manmade vibrations from such activities as blasting and heavy truck or train traffic can accelerate the natural processes of subsidence, or induce subsidence over manmade voids. Subsidence can result in serious, localized structural damage to buildings, roads, irrigation ditches, canals, streams, underground utilities, and pipelines. The HMPC noted that sinkholes have occurred near a hospital as a result of groundwater pumping. Subsidence will be addressed in the Groundwater Sustainability Plans currently under development. Geographic Area Figure 5-76 below shows areas statewide that have a recent history of subsidence or are known to be at an increased risk of subsidence. Most studies and concern about land subsidence in California have focused on the Santa Clara Valley, San Joaquin Valley, Sacramento Valley, Antelope Valley, Coachella Valley, and Mojave River Basin Areas. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-264 Figure 5-76 Land Subsidence in California Source: California Department of Water Resources, November 2014 Public Update for Drought Response A 2013 study conducted for the California Water Foundation by James W. Borchers and Michael Carpenter of Luhdorff & Scalmanni Consulting Engineers observed: “As in much of California, the population of San Luis Obispo County has grown substantially. Land has been converted from dry farming and grazing to irrigated agriculture and urban development. Groundwater has been relied upon to make up for shortages of surface water.” (Borchers & Carpenter, p65) ••• H)'drologk R!!cglon 80000 rv cau y aouncl11,y M jorH gfiw11y Major Ca,qil ~: ~~·t111lill~---~[D -<o'!;ffl~ ~~IJ ""!llll'h.i -• ~~ly ,tsa;. llMifwnllllld~ .!'.1141 ~g,;, -.-t"'"Yla~ a_..,.rp:nr.mi1D_...,.~.,lfw~ ""P" ll!l1!Df !io ~~i'l.tl'i/lN111-srott..-d/oQ/--,n ml!'Wffl""".9....,,.,r:I rl!I l!vr;iort'MI , :iidwn wc.riiiont ■ ~ nt~lit:lil IL,arg1;1 A t; of Subska - i=J ,ftKen w ldeMe ■, 11eir~1~ni:1:r -,TM,;!~ c:::1 , lll1'1!o$;!11,anel I'! ■ Hlrtririaol SI.IIEllfl!oca C::11 Hlrtcmi!~ Con"tiAUOU!i GPSS,1ilticm OlmLdaflv.a Su Mld11111u l C-.: I !ndl 1 •. 2.5 Inches B-5 1~ • '.:i-lillh e1 Amv. Elrtemoine :lff Station -n.nd 1 .A Sub!Mll11,;i1 NlHl:i!: 1"' "" Unkno\m ~ ~ -J.t.,dy Ho ot ro 11tUI .-d ~ n~mrb.,;,z:a,~-.,_,,,_, ... ~ 11ii!sma Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-265 That study identified several locations in San Luis Obispo County at increased risk of land subsidence, primarily the area surrounding Paso Robles. The City of San Luis Obispo and the village of Cambria have also experienced significant land subsidence, as described below under Previous Occurrences. Extent (Magnitude/Severity) A lack of data makes it difficult to predict the magnitude of future land subsidence incidents in San Luis Obispo County. As shown in Figure 5-76 above, most of the documented land subsidence in the county has been of 1” or less. However, that can still be enough to cause structural issues. The largest documented land subsidence measured in San Luis Obispo was a one-time drop of 12” that occurred in the City of San Luis Obispo in 1991. Ongoing displacements of as much as 12” per year have been documented in other parts of the state. The possibility of similar subsidence issues developing in San Luis Obispo County in the future cannot be ruled out. Previous Occurrences Land Subsidence had been an occasional issue in San Luis Obispo County for decades. The 2013 Borchers & Carpenter study listed three documented instances of significant land subsidence in San Luis Obispo County: 1976-1977, Cambria “[E]arth fissures resulting from substantial decline of groundwater levels during the 1976-1977 drought damaged buildings and other infrastructure. Subsequently, the [Village] of Cambria developed additional sources of water for public supply; since then groundwater levels have not returned to historical low levels and fissuring has not reoccurred.” (Borchers & Carpenter, p67) 1991, City of San Luis Obispo: “The [City] of San Luis Obispo… is dependent on local water sources, including surface reservoirs and groundwater, for municipal water supplies. Water shortages became severe during the 1987-1992 drought. Mandatory water rationing was enforced in 1989. When one of the two surface-water reservoirs dropped to its minimum pool elevation in 1990, the city increased groundwater extraction dramatically to meet water demands…. In 1991, tenants and owners of businesses near two of the city wells began to notice unusual effects on their infrastructure. The Bear Valley Shopping Center, a strip mall on Los Osos Valley Road, experienced differential subsidence; floors were shifted unevenly. The middle of the long, narrow mall subsided less than either end of the building so that the floor had an inverted V-shape in its long dimension. Doors and windows would not close properly, and sidewalks sloped back toward the building so that slot drains had to be cut in order to remove pooling precipitation. A surveyor measured a 12-inch drop in the floor along the 45-foot length of one store. After the floor was leveled, a 1-foot step had to be built to allow safe access to the store…. The adjacent building housing the Sunset Honda dealership had to be razed and completely rebuilt. Many homes in the nearby development were damaged. Owners of the strip mall successfully sued the city and were awarded $1 million in damages) …. After that settlement the automobile dealership and many homeowners filed claims with the city. Total cost of the claims was about $2 million.” (Borchers & Carpenter, p66-67) 1997, Paso Robles: “[T]hree areas northeast of Paso Robles and one area northeast of Atascadero subsided during March 28-August 15, 1997. The maximum downward displacement northeast of Paso Robles during this 6-month period was 2 cm (0.8 in), whereas groundwater levels declined about 18 m (60 ft) during the ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-266 same period (Valentine et al., 2001). It is likely that concentrated pumping is responsible for localized land subsidence. The small area of deformation in the Atascadero area subsided 2.8 to 5.6 cm (about 1 to 2 in), coincident with seasonal water-level declines of about 16 m (54 ft). Small amounts of subsidence owing to seasonal changes in groundwater levels may be elastic and recoverable. However, during 2013 substantially declining groundwater levels have been reported. Many formerly reliable wells have gone dry. Interferograms spanning 1997-2013 could indicate whether declining groundwater levels have triggered inelastic compaction of aquifer sediments and permanent subsidence in Paso Robles area.” (Borchers & Carpenter, p66) Additionally, the 2015 City of Atascadero Local Hazard Mitigation Plan noted that Highway 1 west of Atascadero closes almost every winter due to land subsidence. The HMPC also noted that in San Simon there has been a sinkhole problem near a hotel parking lot. Probability of Future Occurrences Occasional. Land subsidence has been a recurring issue in San Luis Obispo County for decades and can be expected to continue in the future. The frequency of future land subsidence incidents in the county will largely be dependent on the mitigation actions and pumping regulations initiated by the state, the county, and local regulations. Climate Change Considerations The most likely impact that climate change will have on land subsidence risk is the potential for extended and severe drought, which could likely result in more groundwater pumping and human-induced subsidence. During periods of drought, water levels may be drawn too low, which results in an irreversible compaction of aquitards. The water cannot recharge the layers, causing permanent subsidence and diminishment of groundwater storage capacity Vulnerability General Property The lack of detailed data on land subsidence in San Luis Obispo County makes it difficult to quantify potential losses. Most subsidence instances result in relatively minor damage and settling of buildings. But in some cases, subsidence can result in serious structural damage to buildings, roads, irrigation ditches, underground utilities, and pipelines. Damages associated with the 1991 subsidence in City of San Luis Obispo resulted in $2 million dollars’ worth of insurance claims. ($3.7M in 2018 dollars.) Subsidence can also disrupt and alter the flow of surface or underground water, as well as reducing the future capacity of aquifers. People This hazard typically results in property damage, not risk to human life. Social Vulnerability Due to the gradual nature of land subsidence it is not anticipated to have social vulnerability consequences. Earthquake-induced ground failure and subsidence is considered in that hazard’s impacts. Critical Facilities and Infrastructure Linear infrastructure (roads, buried pipelines) tends to have the most risk to land subsidence. Statewide, subsidence has caused damage to dams and levees, canals, roads and bridges, water and sewer lines, ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-267 pipelines, well casings, and aircraft runways, in addition to a variety of buildings and other structures. The threat to the California Aqueduct has been identified as a significant concern for the state. Economy Damage resulting from land subsidence can cause direct economic losses in the form of needs structural repairs to affected buildings and facilities. As seen in the 1991 City of San Luis Obispo incident, subsidence can disrupt individual businesses causing temporary closures and sometimes necessitating significant repairs. It can also result in indirect losses, such as from increased taxes and decreased property values. However, the localized nature of most subsidence events limits their overall economic impact at the jurisdictional level. Historic, Cultural, and Natural Resources Historic and cultural facilities are just as susceptible to subsidence-related damage as other structures. However, there is not sufficient data to identify specific historical or cultural facilities at increased risk from this hazard. Typically, there is little impact to the natural environment from land subsidence. However, it is possible for subsidence events to disrupt and alter the flow of surface or underground water, an impact that may not be noticed until long after the fact. Furthermore, soil compaction resulting from subsidence can permanently reduce aquafer capacity, impacting water supplies long into the future. Future Development While vulnerability to this hazard is not anticipated to increase with new development, increased water pumping resulting from new development has the potential to increase the frequency and severity of subsidence. This could be especially important in Paso Robles, given that area has higher subsidence potential and is projected to experience above-average growth. Increased efforts to monitor and manage groundwater pumping, increased accuracy of mapping, and emphasis on appropriate grading and ground compaction during development will help alleviate vulnerability for future development in unknown areas of risk. Risk Summary While a significant portion of San Luis Obispo County is potentially at risk from land subsidence, the localized nature of these incidents makes the overall significance of this hazard Low. • The localized nature of land subsidence incidents limits their overall impact at the county level. • While land subsidence can potentially occur throughout the planning area, the Paso Robles area has been identified as having a higher risk for the hazard. Historical subsidence incidents have also been documented in the City of San Luis Obispo. • There is a shortage of data on this hazard in San Luis Obispo County. Most studies on land subsidence in California have focused on the Santa Clara Valley, San Joaquin Valley, Sacramento Valley, Antelope Valley, Coachella Valley, and Mojave River Basin Areas. • Increased drought conditions resulting from climate change has the potential to result in more groundwater pumping, which could lead to more human-induced subsidence. • Land subsidence can alter the flow of surface or underground water, an impact that may not be noticed until long after the fact. • Related Hazards: Drought ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-268 Table 5-103 Subsidence Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Significant Occasional Negligible Low City of Arroyo Grande Limited Unlikely Negligible Low City of Atascadero Significant Likely Negligible Low City of Grover Beach Limited Unlikely Negligible Low City of Morro Bay Limited Unlikely Negligible Low City of Paso Robles Likely Limited Negligible High City of Pismo Beach Limited Unlikely Negligible Low City of San Luis Obispo Significant Occasional Negligible Low Avila Beach CSD Limited Unlikely Negligible Low Ground Squirrel Hollow CSD Extensive Occasional Limited Low Heritage Ranch CSD Extensive Occasional Limited Low Los Osos CSD Limited Unlikely Negligible Low Nipomo CSD Limited Unlikely Negligible Low San Miguel CSD Limited Occasional Limited Low San Simeon CSD Significant Likely Limited Low Templeton CSD Limited Unlikely Negligible Low Cayucos Sanitary District Limited Unlikely Negligible Low Port San Luis Harbor District Limited Unlikely Negligible Low San Luis Obispo FCWCD Significant Occasional Negligible Low South San Luis Obispo Sanitary District Limited Unlikely Negligible Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-269 5.3.14 Tsunami and Seiche Hazard/Problem Definition A tsunami is a wave, or a series of waves, caused by a displacement of the ocean floor, usually by movement along an earthquake fault. These events are also often referred to as tidal waves or seismic sea waves. In deep ocean water, tsunamis may travel as fast as 600 miles per hour. As they approach the shore, waves may increase in size and can cause extensive damage to coastal structures. Per the SMS Tsunami Warning website, “after a sudden displacement of a large water volume by seismic activity (earthquake), the ocean floor is raised or dropped, and large tsunami waves can be formed by gravitational forces. Waves travel outward from the quake zone in all directions in a ripple effect (propagation). The resulting waves can be extremely dangerous and devastating to low-lying coastal areas as they enter shallow water and hit the shoreline. [However] a tsunami can occur at any state of the tide and even at low tide it will inundate coastal areas if the incoming waves surge high enough.” Withdrawal of the sea may be a precursor to the arrival of the first wave. After the first wave appears, waves may continue to arrive at internals for several hours. Intervals between successive waves may be similar. If the second wave appears 20 minutes after the first, it is likely that a third wave (if there is one) would arrive 20 minutes after the second. The first wave may not be the biggest. Yet the largest wave usually occurs within the first ten waves. The height the sea level rises above mean high tide line is referred to as runup. Seiche (pronounced “seish”) is defined as oscillations of enclosed and semi-enclosed bodies of water, such as bays, lakes, or reservoirs, due to strong ground motion from seismic events, wind stress, volcanic eruptions, and local basin reflections of tsunami. Seiches can result in the creation of long-period waves which can cause water to overtop containment features or cause seiche runup on adjacent land masses, similar to tsunami runup. Geographic Area There are earthquake faults located all over the county as displayed in Figure 5-77 (more information under the Earthquake and Liquefaction section). Offshore faults and related seismic activity could cause tsunamis off the coast of San Luis Obispo County, even faults thousands of miles away. Other earthquake faults, such as those near some of the bigger reservoirs and lakes like the Nacimiento Reservoir on the north (to the west of the Rinconada Fault Zone), Twitchell Reservoir (crossed by the West Huasna Fault Zone), and Soda Lake (near active or potentially active Fault Zones like San Juan) could affect these and other bodies of water and cause seiches, if they experienced seismic activity. As such, seiche hazards could occur in any reservoir or closed water body in the County, as well as in Morro and San Luis Bays. Figure 5-78 displays the tsunami-specific inundation zones, as determined by the California Department of Conservation. Tsunami inundation essentially affects most of the county’s coastal areas, since flooding would originate from earthquake or fault movement from the Pacific Ocean. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-270 Figure 5-77 Earthquake Faults in and Offshore of the County of San Luis Obispo Monterey -- PACIFIC OCEAN ·1ed 3/201 9; I Map comp1 . purposes on y. ·intended for planninlg Obispo County, . San UIS A Open Data Source . GER Database , C US Census Tl 0 Data Portal , USGS ••• Kings 20 40 Miles Waterwa ys Lakes --+--+ Railroads -~ Highway ·ties unties e Faults Potentia ll y Act ive ry Faults USGS Quaterna N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-271 Figure 5-78 Tsunami Inundation Areas on the Coast of San Luis Obispo County PACIFIC OCEAN ~ Tsunami Inundation Waterways Lakes --+--+ Rai lroads --Highway --Freeway ••• Map compi led 3/2019; intended for planning purposes only. Data Source: San Luis Obispo County, US Census TIGER Database, CA Open Data Portal, CA Dept. of Conservat ion MONTEREY I 0 10 20 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-272 The Tsunami Response Plan for San Luis Obispo County uses as its planning basis all those coastal communities, recreation and developed areas with an elevation of 50 feet above mean sea level. In general, much of the coast of the County is protected by wide beaches, coastal dunes, or sea cliffs that provide protection for coastal developments. Areas most vulnerable to the tsunami hazard are developments or infra-structure near the mouths of streams that drain into the Pacific Ocean. They include: • San Simeon Creek in San Simeon • Santa Rosa Creek in Cambria • Cayucos Creek, Little Cayucos Creek, Old Creek and Willow Creek in Cayucos, • Morro and Avila Paul Creeks in Morro Bay, Chorro Creek in Morro Bay/ South Bay area • San Luis Obispo Creek in Avila • Pismo Creek in Pismo Beach, and • Meadow Creek and Arroyo Grande Creek in Oceano Extent (Magnitude/Severity) As noted in Table 5-104, the historic record shows that significant tsunamis typically have been generated from distant earthquake sources. It has been estimated that the 100- and 500-year tsunami runups in the study area are based on far-field source generation locations (such as the Aleutian or Chile-Peru Trenches). Estimated tsunami runup along the Cayucos/Morro Bay coastline is approximately 9.5 feet to 24.2 feet for the 100-year and 500-year events, respectively. Those runups were calculated using astronomical high tides and compare well with recorded tsunamis that have occurred in other locations along the California Coast. However, the worst-case scenario would occur if a tsunami occurred during a meteorological high tide (storm surge), which would add an estimated 14.5 feet (4.5 meters) to the runup values calculated. Thus, with a worst-case scenario, the estimated tsunami runup for the 100-year and 500-year would be approximately elevation 24 and 39 feet above mean sea level, respectively. When it comes to seiches, significant waves in these water-bodies are not anticipated because they are simply not large enough. Past Occurrences Tsunamis have done great damage to communities located on the California Coast. A tsunami in 1964, following an earthquake in Alaska, killed 12 people in Crescent City and damaged piers and boats in Morro Bay as the bay emptied and filled every 15 minutes for over an hour. On March 11, 2011, a great quake (9.0) struck northern Japan. Nearly 12 hours later, approximately $500,000 in damage was recorded to piers and docks in Morro Bay as a result of a tsunami from this earthquake. At the Center of Coastal Marine Science in Morro Bay (near the back of the bay), an oceanographer recorded a 6ft. surge, while fisherman and Coast Guard personnel estimated an 8-9ft. surge at the Coast Guard pier near the entrance to the harbor. Table 5-104 contains a summary of tsunami related events affecting the county from 1868 to 2018. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-273 Table 5-104 Historical Tsunamis in San Luis Obispo County Location Date of Incident Intensity Description Morro Bay 1868 Unknown Unknown Cayucos 4/16/1877 Height: 3.6 meters California Morro Bay 1878 Reportedly overtopped sand spit between the bay and the ocean Unknown Unknown Pismo Beach 1927 Height: 1.8 meters California Avila & Morro Bay 4/1/1946 Height: 1.3 meters Source Magnitude: (Ms) 7.3 Source location: Alaska Source Event: E. Aleutian Islands Travel time: 5 hours Avila Beach 11/4/1952 Height: 1.4 meters Source Mag.: (Ms) 8.2 (Mw) 9 Source location: Russia Source event: Kamchatka Travel time: 8 hours Pismo Beach 5/22/1960 Height: 1.4 meters Source Mag.: (Ms)9.5 Source location: Chile Source event: Central Chile Avila & Morro Bay 3/28/1964 Height: 1.6 meters Source Mag.: (Ms)9.2 Source location: Alaska Source Event: Gulf of Alaska Travel time: 5 hours Morro Bay 3/12/2011 Height: 1.5 meters Source Mag.: (Ms)9.0 Source location: Japan Source Event: Pacific Ocean near Honshu Travel time: 12 hours Coast of San Luis Obispo County 9/16/2015 8.3 Magnitude An 8.3 magnitude earthquake that struck off the coast of Chile, which led the National Tsunami Warning Center to issue a tsunami advisory at 1743 PST for a swath of California, from Orange County to north of San Luis Obispo. All beaches, harbors, piers, and marinas in the Cities of Seal Beach, Huntington Beach, Newport Beach, Laguna Beach, Dana Point and San Clemente, including County and State beaches were closed through 0500 PST on the 17th. Tsunami wave heights were observed to be just under one foot along the Orange County coast. The Orange County EOC reported no significant coastal flooding, but to be aware of the high likelihood of strong currents and waves dangerous to persons in or near the water. The advisory was lifted around 1100 PST on the 17th. Source: County of San Luis Obispo Hazard Mitigation Plan 2014; NOAA’s NCEI Storm Database 2019 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-274 Probability of Future Occurrences Though damaging tsunamis have occurred infrequently in California, they are a possibility that must be considered in coastal communities. It is possible that tsunami flooding hazards will increase and worsen with sea level rise. The Central Coast is most vulnerable to a tsunami generated by an earthquake along the Aleutian-Alaska megathrust (an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian Islands). Present day inundation risk maps combining multiple tsunami generation sources have been produced by the California Geologic Survey and Department of Conservation. In the 151 years since the first recorded tsunami that affected the County of San Luis Obispo there have been 10 events total. This amounts to a probability of tsunami activity once every 15 years on average; as such, the expected future occurrence for this hazard is occasional. Climate Change Considerations Coastal areas in San Luis Obispo County are likely to become more vulnerable to tsunamis over the long term due to sea level rise trends which could contribute to deeper and more destructive tsunamis in the future (see the Coastal Hazards section for more details on sea level rise). Vulnerability (Medium) Tsunamis cause damages to many aspects of communities, including structures, properties, and those arising from the disruption of services. In addition, populations are often affected by being displaced or hurt by the inundation and destruction following a tsunami (e.g. debris generation). While seiches can be destructive as well, due to the lack of a GIS layer noting seiche-caused inundation or other damages, no further analysis is carried out to determine seiche vulnerability in the county, and the perceived vulnerability is low due to the relatively small water bodies that could be affected. General Property A tsunami event occurring along the coast of the County could have devastating effects in terms of property damage to piers, docks, floats, and to moored boats. During the 2019 update of this plan, a GIS analysis of improved property exposure to tsunami inundation areas was performed. GIS analysis indicates approximately $594 million in improved values of parcels found to intersect with the tsunami inundation layer, though with contents added into the parcel valuation estimates the total value of parcels is $886 million. About $460 million of that value is within unincorporated county areas. The loss estimate percentage used for tsunami inundation is 100% of a parcel’s total value, due to the powerful and destructive nature of seismic-induced wave flooding. Table 5-105 and Table 5-106 summarize the improved values, content values, total values, loss estimates, and populations at risk of tsunami inundation in the county, broken up by jurisdiction in the first table, and property type in the second. To find which parcels were in inundation areas, an intersect of improved parcel centroids was performed with tsunami inundation areas. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-275 Table 5-105 Parcels in Tsunami Inundation Areas, by Jurisdiction - San Luis Obispo County Jurisdiction Property Count Improved Value Content Value Total Value Loss Estimate Population Grover Beach 233 $50,630,647 $28,103,300 $78,733,947 $78,733,947 248 Morro Bay 332 $96,361,707 $49,256,580 $145,618,287 $145,618,287 602 Pismo Beach 427 $134,807,357 $66,105,867 $200,913,224 $200,913,224 876 Unincorporated 1,402 $313,191,018 $147,588,673 $460,779,691 $460,779,691 2,515 TOTAL 2,394 $594,990,729 $291,054,419 $886,045,148 $886,045,148 4,242 Source: CA Department of Conservation 2019; SLO County Planning and Building, and Assessor’s Office; ParcelQuest; Wood Plc Parcel Analysis Table 5-106 Parcels in Tsunami Inundation Areas by Parcel Type - San Luis Obispo County Property Type Property Count Improved Value Content Value Total Value Loss Estimate Population Agricultural 9 $299,370 $299,370 $598,740 $598,740 -- Commercial 181 $54,605,778 $54,605,778 $109,211,556 $109,211,556 -- Government/Utilities 197 $398,544 -- $398,544 $398,544 -- Other/Exempt/Misc. 247 $54,904,145 -- $54,904,145 $54,904,145 -- Residential 1,097 $266,741,474 $133,370,737 $400,112,211 $400,112,211 2,753 Mobile/Manufactured Homes 10 $18,839,243 $9,419,622 $28,258,865 $28,258,865 25 Multi-Family Residential 473 $93,561,899 $46,780,950 $140,342,849 $140,342,849 1,187 Residential: Other 110 $76,048,695 $38,024,348 $114,073,043 $114,073,043 276 Industrial 17 $5,702,410 $8,553,615 $14,256,025 $14,256,025 -- Vacant 53 $23,889,171 -- $23,889,171 $23,889,171 -- TOTAL 2,394 $594,990,729 $291,054,419 $886,045,148 $886,045,148 4,242 Source: CA Department of Conservation 2019; SLO County Planning and Building, and Assessor’s Office; ParcelQuest; Wood Plc Parcel Analysis Based on this analysis there are 2,394 developed parcels within tsunami hazard areas (displayed in Figure 5-79). The greatest exposure of general property summarized in the tables above is generally with residential properties; note the lack (or low) improvement or content values for government/utilities and other/exempt/miscellaneous parcels is due to these properties being exempt for tax assessment purposes. More specifics on the developed parcels exposed to this hazard are included in Appendix E, while descriptions of the parcel analysis can be found in the Assets Summary section. The unincorporated portions of the county’s coast have the most properties in tsunami inundation areas. There is a high level of uncertainty as to the actual risk to these exposed parcels (based on built properties’ height above ground and other factors), thus a more specific loss estimation is not provided. A more detailed, site specific analysis would be needed to assess actual risk within the identified parcels. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-276 Figure 5-79 Parcels Within Tsunami Inundation Areas on the Coast of San Luis Obispo County PACIFIC OCEAN • Parcels in Tsunami Inundation Areas Ill Tsunami Inundation Wate rw ays Lakes ----+--+ Railroads ••• Highw ay Free way Map compiled 3/2019 ; intended for pl ann ing purposes only . Data Sou rce : Sa n L ui s Obispo County, US Census TIGER Dat aba se, CA Open Data Portal, CA Dept. of Co nserva tion , ParcelQuest MONTEREY 0 10 20 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-277 People People could be caught in either a tsunami wave or debris generated by tsunami inundation, potentially leading to injury or death. People affected by a tsunami event could also be displaced from their homes or be hurt inside them. Per the parcel analysis summarized in Table 5-105 and Table 5-106, the highest number of people at risk of tsunami inundation (a total of 2,515 of 4,242 potentially at risk county-wide) are located in the unincorporated coastal areas, mostly in residential properties of all types. The total people at risk per parcel were calculated by multiplying the average number of persons per household in the County of San Luis Obispo (2.51) times the number of residential parcels where tsunami inundation occurs. The HMPC noted that the population in Pismo and Grover Beach area swell with beachgoing tourists. The Oceano Dune State Park has as much as 10,000 to 40,000 visitors on a busy summer weekend and on holidays. Tourists may not be familiar with the risk tsunamis pose leading to them to not heed warnings or know where to go for safety. Social Vulnerability Since tsunamis are coastal hazards, those communities along the shore and where social vulnerability indices are higher will be of most concern. These include San Simeon, Grover Beach, and Oceano in particular, followed by medium-high vulnerability in Morro Bay and Los Osos. Tsunamis can cause injuries or death from direct wave force or indirectly, via debris generated or inundation caused in communities exposed. Evacuation aid will be of highest priority in those high vulnerability and high hazard exposure areas discussed, as people who rely on assistance for displacement (e.g. those with accessibility needs), or who require translation services or other specialized resources would be most vulnerable. Critical Facilities In addition to buildings, some utilities and transportation infrastructure are vulnerable to tsunamis and the inundation that flows inland. They present a particular vulnerability because of their proximity to the coast, such as Highway 1, and susceptibility to flooding and damage. Failure of any component along major utility and transportation lifelines can result in failure to deliver services over a large region or even fail to enable flows of people and goods (due to road closures, etc.). Once broken or interrupted in major ways, transmission of a commodity through the lifeline ceases, which can have catastrophic repercussions down the line: loss of power to critical facilities such as hospitals, impaired disposal of sewage, contamination of water supplies, potential release of flammable fuels, and so on. Therefore, the overall impact of lifeline failures and transportation infrastructure, including secondary failure of systems that depend on lifelines, can sometimes be much greater than the impact of individual building failures or breakages, if not significantly compound the already damaged buildings and internal contents. The following table summarizes the number and types of critical facilities found to be at risk of tsunamis. These results were found by performing overlay analysis of the critical facilities and the tsunami inundation layers in GIS. Most of these facilities at risk are found in Morro Bay, though a few also in the unincorporated portions of the county and one in Grover Beach. Overall, a total of 14 critical facilities are found within tsunami inundation zones across the county. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-278 Table 5-107 Critical Facilities in Tsunami Inundation Areas by Type - San Luis Obispo County Jurisdiction Critical Facility Type Count Grover Beach Water Treatment Facilities 1 TOTAL 1 Morro Bay Wastewater Treatment Plant 1 Public Schools 1 Energy Commission Facilities 1 Power Plant 1 Microwave Service Towers 3 TOTAL 7 Unincorporated Wastewater Treatment Plant 2 Local Law Enforcement 1 Fire Stations 1 Airport 1 Energy Commission Facilities 1 TOTAL 6 GRAND TOTAL 14 Source: San Luis Obispo County Planning & Building Dept/GIS, HIFLD, CA Department of Conservation, San Luis Obispo County Community Services Districts, Wood GIS analysis The Diablo Canyon Power Plant is not considered to be at risk as it is located on a marine terrace 85 feet above the sea level. The cooling intakes and release structures for the plant, which are located at sea level, are protected by natural barriers and a concrete jetty. Economy Economic impacts typically center around transportation routes closed by damages from debris carried by the wave activity, and hence general inundation. Roads used to transport goods across the county or provide access by visitors and tourists might be limited in use or even shut down, causing stoppage of services and commodity flows, and possibly leading to reduced revenues and economic activity. Historic, Cultural, and Natural Resources Tsunami inundation effects on the environment would be similar to those caused by flooding from other causes but would likely prove significantly more destructive. Water could erode beaches and cover the environment with debris. For the most part the environment is resilient and would be able to rebound from whatever damages occurred, though this process could take years. GIS analysis indicates the following six historic properties are potentially at risk to tsunami inundation. Table 5-108 Historic Properties in Tsunami Inundation Areas - San Luis Obispo County Name Year Area Plan Southern Pacific Railroad Depot San Luis Bay Area Plan-Inland Avila Valley Historic Site 1 San Luis Bay Area Plan-Inland Avila Valley Historic Site 2 San Luis Bay Area Plan-Inland Captain James Cass House 1872 Estero Area Plan Captain James Cass House & Adjacent Buildings 1872 Estero Area Plan The Sebastian Store 1860 North Coast Area Plan Source: County of San Luis Obispo Planning and Building Dept., 2019 ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-279 Future Development Areas slated for future development along the coast should consider potential impacts from tsunami inundation, particularly development of new critical facilities or vulnerable populations (e.g. schools). For this plan, a GIS overlay analysis of building construction permits for residential and commercial properties was additionally performed across the county, pulling from permits submitted from 2014 to early 2019. This assessment provides a general idea of how many future properties may be constructed, or may have upgrades done, within tsunami inundation areas (see Table 5-109). More detail on the specific types of permits granted, particularly the kind of work class and case type for each permit group, can be found under the Asset Summary section of this plan. Table 5-109 Building Permits Submitted within Tsunami Inundation Areas from 2014-2019 Work Class Case Type Work Class Type Total Conditional Use Permit Land Use 26 Minor Use Permit Land Use 115 New Structure PMTC - Commercial Permit 23 PMTR - Residential Permit 49 TOTAL 213 Source: San Luis Obispo County Planning & Building Department, CA Department of Conservation, Wood GIS analysis Risk Summary The overall significance of tsunami inundation and seiche activity in San Luis Obispo County is Medium. These events are recurring in nature and could disrupt critical elements of the County’s infrastructure. In addition, San Luis Obispo County has a significant coastline with much recreation and development oriented toward the coast. The areas of Port San Luis and Morro Bay harbor are most vulnerable to tsunamis due to their location at the stream mouths of creeks draining into the Pacific Ocean. • Based on historical evidence tsunami and seiche activity can occur in the county, though not frequently. • Effects on property: Property loss can be significant depending on wave height; 2,394 improved parcels are found in tsunami inundation areas based on GIS analysis, most of these in unincorporated county portions with concentrations in the cities of Morro Bay, Pismo Beach, and Grover Beach, • Effects on people: People are at risk from tsunamis in San Luis Obispo County. An estimated 4,242 people might be displaced from their homes or even hurt based on the location of their residences along the coastal inundation areas. • Effects on critical facilities and infrastructure: Tsunami inundation can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage. Disrupted transportation routes are likely to occur as well and cause considerable inconvenience and closure of services or commodity flows. Based on GIS analysis, there are a total of 14 critical facilities found within tsunami inundation areas, with most of them in Morro Bay (7), some in the unincorporated portions of the county (6), and 1 in Grover Beach. • Effects on economy: Tsunamis disrupt major transportation corridors, affecting the economy • Related hazards: Earthquake, Coastal Storm/Coastal Erosion/Sea Level Rise. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-280 Table 5-110 Tsunami Risk Summary Jurisdiction Geographic Area Probability of Future Occurrence Magnitude/ Severity (Extent) Overall Significance San Luis Obispo County Significant Occasional Limited Medium City of Arroyo Grande N/A N/A N/A N/A City of Atascadero N/A N/A N/A N/A City of Grover Beach Limited Occasional Limited Low City of Morro Bay Extensive Occasional Catastrophic High City of Paso Robles N/A N/A N/A N/A City of Pismo Beach Significant Occasional Critical Medium City of San Luis Obispo N/A N/A N/A N/A Avila Beach CSD Significant Occasional Critical Medium Ground Squirrel Hollow CSD N/A N/A N/A N/A Heritage Ranch CSD N/A N/A N/A N/A Los Osos CSD Significant Likely Limited Low Nipomo CSD N/A N/A N/A N/A San Miguel CSD N/A N/A N/A N/A San Simeon CSD Limited Unlikely Negligible Low Templeton CSD N/A N/A N/A N/A Cayucos Sanitary District Significant Occasional Critical Medium Port San Luis Harbor District Significant Occasional Catastrophic High San Luis Obispo FCWCD Significant Occasional Critical Medium South San Luis Obispo Sanitary District Limited Occasional Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-281 5.3.15 Wildfires Hazard/Problem Definition A wildfire is an uncontrolled fire spreading through vegetative fuels, posing danger and destruction to property. While wildfires are often the direct result of lightning strikes, most are caused by powerlines or mechanical equipment, or are the result of human activities like debris burns, carelessness, or arson. Wildfires often start in undeveloped areas and public land areas, such as state and national forest lands, but can spread to urban areas where structures and other human development are more concentrated. The predominant dangers from wildfires are: •Injury or loss of life to people in the affected area; and •The destruction of vegetation, property, wildlife. Communities throughout California are increasingly concerned about wildfire safety as increased development in the foothills and mountain areas and subsequent fire control practices have affected the natural cycle of the ecosystem. Wildfire risk is predominantly associated with wildland-urban interface areas, a general term that applies to development adjacent to landscapes that support wildfire. However, significant wildfires can also occur in heavily populated areas. San Luis Obispo County is exposed to a variety of wildfire hazard conditions that varies based on fuels, topography, weather, and human behavior. CAL FIRE, as required by government code 51181, has undertaken a statewide program to map areas of potential wildfire severity, and to describe the potential for wildfires to occur in a given area; the resulting Fire Hazard Severity Zones are shown in Figure 5-80 below. It should be noted that fires are also an important natural component of San Luis Obispo County’s ecosystem. Wildlands need to burn periodically to naturally maintain viable environments. Fuel maintenance (controlled burns, mowing, cattle grazing and other means) is a necessary replacement to uncontrolled wildland fires because of threats to human habitation. Development patterns in rural lands can reduce the ability to manage fuel and defend “values at risk”. Geographic Area Generally, there are three major factors that sustain wildfires and predict a given area’s potential to burn. These factors are fuel, topography, and weather. •Fuel—Fuel is the material that feeds a fire and is a key factor in wildfire behavior. Fuel is generally classified by type and by volume. Fuel sources are diverse and include everything from dead tree leaves, twigs, and branches to dead standing trees, live trees, brush, and cured grasses. Also, to be considered as a fuel source are manmade structures, such as homes and other associated combustibles. The type of prevalent fuel directly influences the behavior of wildfire. Fuel is the only factor that can be modified by humans. Fuel types within San Luis Obispo County are described in Table 5-111 below. •Topography—An area’s terrain and slopes affect its susceptibility to wildfire spread. Both fire intensity and rate of spread increase as slope increases due to the tendency of heat from a fire to rise via convection. The arrangement and types of vegetation throughout a hillside can also contribute to increased fire activity on slopes. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-282 • Weather—Weather components such as temperature, relative humidity, wind, and lightning also affect the potential for wildfire. High temperatures and low relative humidity dry out fuels that feed wildfires, creating a situation where fuel will more readily ignite and burn more intensely. Thus, during periods of drought, the threat of wildfire increases. Wind is the most influential weather factor of the three and its influence can increase rates of spread regardless of temperature and relative humidity. The areas within the county that are subject to increased wildfire risks are generally those communities where urban development abuts non-maintained wildland fuels, resulting in a wildland-urban interface (WUI). When residential development occurs within or adjacent to an area that has a high wildfire hazard severity, the ability of fire fighting forces to combat a fire may also be impaired. When residences are located in the vicinity of wildfire, typical firefighting techniques, such as the use of backfires, may not be feasible. Additionally, firefighting equipment and personnel may be used for structure protection, instead of being used to fight the fire. This results in the need for additional equipment to effectively minimize structural losses and to control the fire. CAL FIRE identifies areas that are at high risk of damage from wildfire based primarily on three factors: • Ranking Fuel Hazards = ranking vegetation types by their potential fire behavior during a wildfire. • Assessing the Probability of Fire = the annual likelihood that a large damaging wildfire would occur in a particular vegetation type. • Defining Areas of Suitable Housing Density that Would Create Wildland-Urban Interface Fire Protection Strategy Situations = areas of intermingled wildland fuels and urban environments that are in the vicinity of fire threats. Population density and the presence of structures are not currently used to determine the fire hazard severity for a particular region, although they do have a significant impact on fire behavior. Based on the above criteria, CAL FIRE has mapped Fire Hazard Severity Zones throughout the county designated as “Very High,” “High,” or “Moderate” as shown below in Figure 5-80. In San Luis Obispo County, most of the area that has been designated as a “Very High Fire Hazard Severity Zone” is located in the Santa Lucia Mountains, which extends from Monterey County to the north, to Santa Barbara County to the south. These areas exhibit the combination of vegetative fuel, topography, and human proximity that contribute to an extreme fire hazard potential. The fact that an area is in a Moderate Hazard designation does not mean it cannot experience a damaging fire. It only means that the probability is reduced, generally because the number of days a year that the area has “fire weather” is less. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-283 Figure 5-80 Fire Hazard Severity Zones in State & Local Responsibility Areas ••• PACIFIC OCEAN Fire Hazard Severity Zones -Very High High Moderate LJ Federal Responsibility A reas or Not Classified -Very High Fire Hazard Severity in LRAs -+--+ Railroads Highway ---Freeway j:::::::j Cities Counties Map compi le d 5/2019 ; intended for planning purposes only. Data Source : San Luis Obispo County, US Census TIG ER Database , CA Open Data Portal , CalFire Monterey B "'·---, \ I ~n~ \ -~ 1 ------------------~~ 10 20 i I I i I i i I l!; __ _ l_ ~-L L t_l '------;, . i I Santa Barbara 40 Miles Kern N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-284 CAL FIRE has also designated the following San Luis Obispo County communities as being at increased risk from wildfires (http://osfm.fire.ca.gov/fireplan/fireplanning_communities_at_risk): • Adelaida • Arroyo Grande, City of • Atascadero, City of • Avila Beach • Baywood-Los Osos • Cambria • Cayucos • Creston • Grover Beach, City of • Lake Nacimiento • Morro Bay, City of • Nipomo • Oceano • Paso Robles, City of • Pismo Beach, City of • San Luis Obispo, City of • San Miguel • Santa Margarita • Templeton Some unincorporated communities located within the county are not confronted with a high wildfire risk, due primarily to the dominant type of vegetation in those areas. The low-growing native grasses and shrubs found in these communities present a minimal vegetative fuel source and a corresponding low wildfire risk. In the Arroyo Grande and Grover Beach areas, mild coastal summers characterized by cool temperatures and foggy days and nights help to maintain the fuel moisture levels to a point that limits the potential for rapid fire spread. In addition, the topography of those areas is mainly level and well developed in both residential and agricultural land uses. Extent (Magnitude/Severity) Vegetation (or fuel) plays a major role in fire behavior and shaping fire hazard potential. Vegetation distribution throughout the county varies by location and topography, with dramatic differences observed between the eastern, agricultural and ranching portions of the county, and the more mountainous central and southern regions. Land cover distribution within the county can be classified into 14 different fuel models, as presented in Table 5-111. The most abundant vegetative cover within San Luis Obispo County is herbaceous (46.9%), or annual grassland, distributed primarily in the inland valley and plain areas east of the La Panza, Garcia, and Santa Lucia Ranges. While this fuel type can burn quickly under strong, dry wind patterns, it does not produce the high heat intensity and high flame lengths associated with scrub, chaparral, and forest fuel types. Other significant vegetative cover types include: light brush (16.5%), pine/grass (12.1%), and hardwood/conifer litter (8.3%). These vegetation types are primarily associated with the steeper, upland areas in the La Panza, Garcia, and Santa Lucia Ranges throughout the central portion of the county. Fire behavior in brush fuel types produces higher flame lengths than that in grassland, although spread rates are typically slower. Fire behavior in forests is variable, depending on surface fuel conditions and the presence of ladder fuels. Table 5-111 Fuel Model Types in San Luis Obispo County Fuel Model Number Description Approximate Acreage Percent Cover 1 Grass 997,984 46.98% 5 Light Brush 349,780 16.46% 2 Pine/Grass 256,610 12.08% 97 Agriculture 220,097 10.36% 8 Hardwood/Conifer Litter 176,008 8.29% 4 Tall Chaparral 88,290 4.16% 28 Urban 19,687 0.93% 10 Heavy Conifer Litter w/ Understory 9,630 0.45% ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-285 Fuel Model Number Description Approximate Acreage Percent Cover 6 Intermediate Brush 3,103 0.15% 98 Water 1,726 0.08% 15 Desert 545 0.03% 9 Medium Conifer 242 0.01% 12 Medium Slash 228 0.01% Source: FRAP Fuel loading in developed areas susceptible to wildfire becomes even more complex. The introduction of some ornamental plantings as landscaping and groundcover can dramatically increase the fire loading of a neighborhood. Gazebos, fencing, patios, decks and even the structures themselves add even more fuel. Once structures become involved in fire, the problem compounds as embers cast out thousands of feet onto combustible roofs well removed from the wildland area. Steep terrain also plays a key role in the rate at which wildfires spread, as fires will normally burn much faster uphill. Generally, when the gradient of a slope doubles, the rate of spread of a fire will also double. Steep topography also channels air flow, thereby creating erratic wind patterns. Fire suppression in steep areas is also complicated by limited accessibility, and the effectiveness of firefighters and equipment are hampered by lack of access roads. Another factor that can increase the severity of wildfires in the county is areas with high percentages of dead trees, as discussed in subsection 5.3.5 on Agricultural Pest Infestation and Plant Disease. The Fire Rating System defined in Table 5-112 describes the characteristics and potential intensity of fires, including the effect on the ability to manage and suppress fires. Fire conditions up through Class 5 are possible in San Luis Obispo County, primarily in the unincorporated areas. Table 5-112 Fire Danger Rating System Rating Basic Description Detailed Description CLASS 1: Low Danger (L) COLOR CODE: Green fires not easily started Fuels do not ignite readily from small firebrands. Fires in open or cured grassland may burn freely a few hours after rain, but wood fires spread slowly by creeping or smoldering and burn in irregular fingers. There is little danger of spotting. CLASS 2: Moderate Danger (M) COLOR CODE: Blue fires start easily and spread at a moderate rate Fires can start from most accidental causes. Fires in open cured grassland will burn briskly and spread rapidly on windy days. Woods fires spread slowly to moderately fast. The average fire is of moderate intensity, although heavy concentrations of fuel – especially draped fuel -- may burn hot. Short-distance spotting may occur but is not persistent. Fires are not likely to become serious and control is relatively easy. CLASS 3: High Danger (H) COLOR CODE: Yellow fires start easily and spread at a rapid rate All fine dead fuels ignite readily, and fires start easily from most causes. Unattended brush and campfires are likely to escape. Fires spread rapidly, and short-distance spotting is common. High intensity burning may develop on slopes or in concentrations of fine fuel. Fires may become serious and their control difficult, unless they are hit hard and fast while small. CLASS 4: Very High Danger (VH) COLOR CODE: Orange fires start very easily and spread at a very fast rate Fires start easily from all causes and immediately after ignition, spread rapidly and increase quickly in intensity. Spot fires are a constant danger. Fires burning in light fuels may quickly develop high-intensity characteristics - such as long-distance spotting - and fire whirlwinds, when they burn into heavier fuels. Direct attack at the head of such fires is rarely possible after they have been burning more than a few minutes. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-286 Rating Basic Description Detailed Description CLASS 5: Extreme (E) COLOR CODE: Red fire situation is explosive and can result in extensive property damage Fires under extreme conditions start quickly, spread furiously and burn intensely. All fires are potentially serious. Development into high-intensity burning will usually be faster and occur from smaller fires than in the Very High Danger class (4). Direct attack is rarely possible and may be dangerous, except immediately after ignition. Fires that develop headway in heavy slash or in conifer stands may be unmanageable while the extreme burning condition lasts. Under these conditions, the only effective and safe control action is on the flanks, until the weather changes or the fuel supply lessens. Source: http://www.wfas.net Major wildland fires can completely destroy ground cover. If heavy rains follow a major fire, flash floods, heavy erosion, land subsidence and mudflows can occur. After a wildland fire passes through an area, the land is laid bare of its protective vegetation cover and is susceptible to excessive run-off and erosion from winter storms. The intense heat from the fire can also cause a chemical reaction in the soil that makes it less porous, and the fire can destroy the root systems of shrubs and grasses that aid in stabilizing slope material. These cascading effects can have ruinous impacts on people, structures, infrastructure, and agriculture. For more details on the extent and expected behavior of fires in the county see the March 2019 San Luis Obispo County Community Wildfire Protection Plan (CWPP). Previous Occurrences 490 wildfires have been recorded in San Luis Obispo County between 1900 and 2018, as shown in Figure 2 below. This equates to an average of around four wildfires per year. Most of these fires burned from a few hundred to a few thousand acres; the median acreage burned in those 490 wildfires is 277 acres, while the mean acreage burned is 2,554 acres due to several large fires driving up the average. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-287 Figure 5-81 Fire History in San Luis Obispo County from 1900 to 2018 PACI F IC OCEA N Fire History 1900-2018 1900 -1959 1960 -1979 -1980-1999 -2000-2018 -+--+ Railroads --Highway --Freeway D eities DJ counties ••• Map compiled 2/2019; intended for planning purposes only . Data Source: San Luis Obispo County, us Census TIGER Database, CA Open Data Portal, CalFire 0 Kings Tu lare Kern 10 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-288 Figure 5-82 plots the number of fires in San Luis Obispo County by decade along with the total acreage burned by those fires. The lower number of fires in earlier decades may be at least in part due to less rigorous record-keeping. Nevertheless, a trend toward more wildfires and more acres burned is clearly visible. Figure 5-82 Fire History by Decade in San Luis Obispo County from 1900 to 2010 Source: FRAP. Analysis by Wood While the majority of the past wildfires had relatively minor impacts, the county also has a history of damaging wildfires, with 15 fires burning more than 20,000 acres each since 1900, as shown in Table 5- 113. Table 5-113 Large Fire History (Fires Greater Than 20,000 Acres) Fire Name Year Approx. Acres Burned Damages Avenal’s Fire 1917 21,242 Unknown Unnamed Fire 1921 63,909 Unknown Unnamed Fire 1922 25,637 Unknown Machesna Fire 1939 28,313 Unknown Pilitas #1 Fire 1950 22,844 Unknown Sam Jones Fire 1953 35,455 Unknown Big Dalton Fire 1953 67,701 Unknown Weferling Fire 1960 51,451 Unknown Buckeye Fire 1970 42,307 Unknown Las Pilitas Fire 1985 84,271 Destroyed 10 homes Highway 41 Fire 1994 50,729 Destroyed 42 homes, 61 other structures, and 91 vehicles Highway 58 Fire 1996 106,969 Destroyed 13 homes, numerous other structures & vehicles Logan Fire 1997 49,490 None (remote, unpopulated area) - 1,000 2,000 3,000 4,000 5,000 6,000 7,000 - 500 1,000 1,500 2,000 2,500 3,000 3,500 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s Acres Burned (x1000)Number of Recorded Wildfires# of Fires Acres Burned ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-289 Fire Name Year Approx. Acres Burned Damages Chimney Fire 2016 46,344 Destroyed 49 homes and 21 other structures Alamo Fire 2017 28,834 Destroyed one home and 13 other structures Source: FRAP An analysis of 457 fire starts in the county from 2013 to 2017 where the cause of the fire could be determined found that powerlines and vehicle or equipment use accounted for 70% of ignitions. Table 5-114 Ignition History in San Luis Obispo County, 2013-2017 Ignition Cause Number Percentage Powerline/Vehicle/Equipment Use 319 70% Debris Burning 46 10% Campfire 35 8% Arson 31 7% Lightning 10 2% Smoking 9 2% Playing w/ Fire 7 2% Source: SRA Ignition History for San Luis Obispo County (2013-2017) Probability of Future Occurrences Likely. Based on the historical record, San Luis Obispo County can expect multiple small wildfires most years, with a large (20,000+ acre) damaging wildfire every 7-8 years. The interval between large damaging wildfires varies from as long as 17 years to as short as 1 year. Climate Change Considerations Growing amounts of greenhouse gases coupled with population growth and development are expected to continue impacting California forests and natural resources. Likewise, the effects of climate change have the potential to impact wildfire behavior, the frequency of ignitions, fire management, and fuel loads. Increasing temperatures may intensify wildfire threat and susceptibility to more frequent wildfires in the county. Exactly how climate change will affect total precipitation is not clear, but models suggest that there is a tendency for wetter conditions in the northern part of the state and drier conditions in the south (California Natural Resources Agency 2018a). Forests are also sensitive to variable precipitation events, as the 2012-2017 drought contributed to widespread tree mortality as warmer temperatures stressed trees and made them more susceptible to pests and pathogens (California Natural Resources Agency 2018). Studies noted in California’s Fourth Assessment report note climate change impacts on wind patterns may strongly affect forests, potentially serving as a trigger mechanism for conversion of forest to other types of vegetation (California Natural Resources Agency 2018). Current scientific models expect California will be affected by increased numbers of forest fires with added intensity due to longer warmer seasons, reduced distribution of biodiversity, lack of moisture, changes in ecosystems, drought impacts (e.g. pest diseases and continued spread of invasive species), and other impacts in coming years. The anticipated growth and development described in Section 4 and also be expected to amplify these effects. As seen with the 2017 -2018 wildfires, more damage occurred in developed areas like Santa Rosa in Sonoma County, Montecito in Santa Barbara County, Paradise in Butte ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-290 County, and the Thomas Fire in Ventura & Santa Barbara. The extending of the wildfire season into winter months, coinciding with seasonal high wind patterns, has contributed to severe fires in recent years. Southern California experienced 29 wildfires in December of 2017 alone, and the deadliest and most destructive fire in California history, the Camp Fire, happened in November of 2018. Vulnerability San Luis Obispo County vulnerability to wildfires is of significant concern, with some areas of the planning area being at greater risk than others as described further in this section. High fuel loads in the planning area along with geographical and topographical features create the potential for both natural and human- caused fires that can result in loss of life and property. These factors, combined with natural weather conditions common to the area, including periods of drought, low relative humidity, and periodic winds, can result in frequent and sometimes catastrophic fires. Even the relatively flat and more urbanized parts of the county are not immune to fire; hot and sometimes windy weather combined with dry vegetation and a denser population can result in an increase in the number of ignitions. San Luis Obispo County’s wildfire vulnerability is increased by development encroaching into forested and annual grassland areas, typically referred to as the wildland-urban interface. The conversion of agricultural areas to urban use can further exacerbate this problem. As development continues throughout the planning area, especially in the interface, the risk and vulnerability to wildfires will likely increase. General Property The historical and potential impacts of wildfire on property include crop loss, injury and death of livestock and pets, and damage to infrastructure, homes and other buildings located throughout the wildfire risk area, with greatest potential impact on property, buildings and infrastructure located within high and very high hazard zones including the WUI, and buildings and infrastructure located within forested lands, to include national forests and parks. The Community Wildfire Threat used in this analysis was derived from the Fire Hazard Severity Zones (FHSZ) spatial dataset, which was explicitly developed for adopting new ignition-resistant building code standards and adopted by the California Building Commission in 2007. It is constructed to describe the nature and probability of fire exposure to structures, including those lands that are highly urbanized, but in close proximity to open wildlands. It is broken into State Responsibility Areas (SRA) and Local Responsibility Areas (LRA). Details of the FHSZ mapping project are available on the FRAP website (http://frap.fire.ca.gov/projects/hazard/fhz.html). GIS was used to create a centroid, or point, representing the center of each parcel polygon, which was overlaid on the FHSZ wildfire layer. For the purposes of this analysis, the wildfire hazard zone that intersected the centroid was assigned as the hazard zone for the entire parcel. For purposes of this analysis, it was assumed that every parcel with an improved value greater than zero was developed in some way, thus only improved parcels and their values were analyzed. The Fire Hazard Severity Zones for the SRA and Very High zones in the LRA were analyzed. The county’s parcel layer was used as the basis for the inventory of developed parcels. The results are summarized in the map and tables that follow. Figure 5-83 illustrates the extent of the problem by showing all parcels with improved values above $0, as well as government/utility facilities, that are located within Fire Hazard Severity Zones. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-291 Figure 5-83 Improved Parcels by Fire Hazard Severity Zones PA CIFIC OCEAN Parce ls in Fire Hazard Se verit y Zo nes -+--Ra ilroads • Very High Highw ay • LRA Very High Free w ay 0 Hig h Lakes Fire Hazard Se verity Zones Waterways -~ ••• Ve ry High (SRA) D eities Very High (LRA) [_-=._j Counties Hig h Map compiled 3/2019 ; int ended for pla nnin g purposes only. Data So urce : San Luis Obispo County, US Census TIG ER Database , CA Open Data Portal , CalFire , ParcelQuest 0 0 0 ;, 0 0 0 0 ~ 0 0 0 0 0 00 0 10 20 M il es N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-292 An analysis of the value of those parcels – the improvement value plus estimated value of building contents – quantifies the potential losses from wildfires by severity zones. The results show that nearly $10 billion worth of developed parcels are exposed in the High and Very High Severity zones, with $3.6 billion just in the Very High Severity zone. Residential properties constitute more than half of both the number of parcels and the projected losses. The communities with the greatest exposure are the unincorporated areas, Atascadero, and Pismo Beach. The total values shown in these tables include both structure value and contents and can be used as an estimate of potential losses since wildfires typically result in a total loss. More detailed information on the types and value of properties exposed to wildfire risk can be found in Appendix E. Table 5-115 Wildfire Hazard Exposure – General Property Summary by Jurisdiction Jurisdiction Moderate Severity (SRA) High & Very High Severity (SRA & LRA) Properties Total Value Population Properties Total Value Population Arroyo Grande 5 $2,338,635 8 6 $1,007,592 10 Atascadero - - - 1,594 $611,221,404 3,865 City of San Luis Obispo 6 $5,113,067 8 17 $11,933,805 35 Paso Robles - - - 3 $507,068 5 Pismo Beach - - - 1,068 $501,552,519 2,445 Unincorporated 2945 $1,575,500,560 5,023 20,235 $8,795,910,655 43,310 Total 2,956 $1,582,952,262 5,038 22,923 $9,922,133,042 49,670 Source: San Luis Obispo County Planning & Building/GIS Dept., HIFLD, CalFire, Wood GIS analysis Table 5- 116 Wildfire Hazard Exposure –Property Summary by Type in High and Very High Potential Jurisdiction Moderate Severity (SRA) High & Very High Severity (SRA & LRA) Properties Total Value Population Properties Total Value Population Agricultural 125 $143,496,376 - 310 $534,438,864 - Commercial 28 $26,907,204 - 165 $128,682,700 - Government/Utilities 321 $622,953 - 486 $5,951,421 - Other/Exempt/Misc. 335 $44,838,322 - 926 $76,669,478 - Residential 1,607 $1,116,195,564 4,034 17,198 $8,189,242,350 43,167 Multi-Family Residential 242 $76,914,723 607 546 $182,853,743 1,370 Mobile/Manufactured Homes 126 $34,213,590 316 1,953 $365,563,895 4,902 Residential: Other 32 $83,551,748 80 92 $135,227,636 231 Industrial 6 $33,657,318 - 11 $11,751,548 - Vacant 134 $22,554,465 - 1,236 $291,751,409 - TOTAL 2,956 $1,582,952,262 5,038 22,923 $9,922,133,042 49,670 Source: San Luis Obispo County Planning & Building/GIS Dept., HIFLD, CalFire, Wood GIS analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-293 People Wildland fires result in a high risk for personal injury, loss of life to inhabitants of the fire area and firefighters, and losses of structures and personal property. Wildfires in or near the WUI frequently require emergency evacuation and sheltering, often for many days. As is shown in Tables 5-115 and 5-116 above, 49,670 are estimated to live in High or Very High hazard zones. The data and mapping shown above enables analysis of each jurisdiction’s vulnerability in terms of population and density relative to its risk zone. Population density can also change based on time of day and time of year. For example, the population at California Polytechnic State University, San Luis Obispo (Cal Poly) increases during the academic year, and during daytime hours. The potential for extended power outages as a result of a wildfire event will also have impacts on healthcare facilities and medically vulnerable individuals who are dependent on power for medical assessments and treatments. Other at- risk populations include wildland recreational areas such as state and national parks and forests where persons might be located during a wildfire event, particularly during summer months. Social Vulnerability As shown in Figure 5-80, the highest wildfire hazard severity zones are found north of Grover Beach, east of Nipomo, west of the City of San Luis Obispo, and some near and west of Paso Robles and San Miguel, which happen to be also highest in terms of overall social vulnerability ranking based on the SoVI data presented and discussed in subsection 4.4.1. Other areas of particular concern include Atascadero, Los Osos, and San Simeon, which rank medium-high on the vulnerability scale but are exposed to great wildfire hazard based on potential severity. Critical Facilities and Infrastructure Critical facilities are those community components that are most needed to withstand the impacts of disaster, as previously described in the Assets section. Wildfire impacts to critical facilities can include structural damage or destruction, risk to persons located within facilities, and interruption of facility operations and critical functions. Wood timber bridges are particularly vulnerable to fire. GIS analysis shows that 10 wood timber bridges in the county potentially at risk to wildfires. In addition, six of these bridges have been rated as being in scour-critical conditions, which makes them even more vulnerable to failure or destruction during a post- fire flood or debris flow event. The table below summarizes how many bridges are at risk of which type of wildfire hazard zone and includes the total of scour-critical status bridges. Further details on the bridges at risk are found in Appendix E. Table 5-117 Bridges in Wildfire Hazard Zones in San Luis Obispo County Wildfire Hazard Zone Total Bridges in Zone Scour Critical Total Moderate 6 4 High 2 1 Very High 2 1 TOTAL 10 6 Source: National Bridge Inventory, CalFire, Wood GIS analysis ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-294 Table 5-118 and Table 5-119 summarize the number and types of critical facilities found to be at risk of wildfires. These results were found by performing overlay analysis of the critical facilities and the wildfire hazard zone layers in GIS. Most of these facilities at risk are found in unincorporated portions of the county, with a few in Atascadero, Paso Robles, Pismo Beach, and the City of San Luis Obispo. Overall, a total of 348 critical facilities are found within wildfire hazard zones across the county, and most of these in high or very high hazard zones. The majority of these facilities are communications towers, notably microwave service towers, and energy commission facilities. Also, of note are vulnerable population facilities including schools, day care facilities, and a nursing home (in Atascadero). Details on the specific properties at risk are found in Appendix E. Table 5-118 Critical Facilities in Wildfire Hazard Zones in San Luis Obispo County, by Jurisdiction Jurisdiction Count Atascadero 3 Paso Robles 2 Pismo Beach 2 San Luis Obispo 1 Unincorporated 340 TOTAL 348 Source: San Luis Obispo County Planning & Building/GIS Dept., HIFLD, CalFire, San Luis Obispo County Community Services Districts, Wood GIS analysis Table 5-119 Critical Facilities in Wildfire Hazard Zones in San Luis Obispo County, by Wildfire Zone Wildfire Hazard Zone Count Moderate 109 High 121 Very High 118 TOTAL 348 Source: San Luis Obispo County Planning & Building/GIS Dept., HIFLD, CalFire, San Luis Obispo County Community Services Districts, Wood GIS analysis Economy The economic impacts of wildfire include loss of property, direct agricultural sector job loss, secondary economic losses to businesses in or near wildland resources like parks and national forests, and loss of public access to recreational resources. Fire suppression may also require increased cost to local and state government for water acquisition and delivery, especially during periods of drought when water resources are scarce. Effects on agriculture can be significant. In addition to the obvious impacts on crops and animals, wildland fire can have damaging effects on soil and water that will impact agriculture for an extended period of time. Historic, Cultural, and Natural Resources GIS analysis indicates that 64 historic properties are potentially at risk to wildfires; 51 are located in the High or Very High Severity Zones. Details on the specific properties at risk are found in Appendix E. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-295 San Luis Obispo County also has substantial natural resources potentially at risk from wildfires. As noted earlier, fire is an important natural component of the ecosystem, and wildlands need to burn periodically to naturally maintain viable environments. However, wildfires can have negative impacts on natural resources such as forests, and wildlife habitats. In addition to damaging critical watersheds, post-fire runoff can pollute waterways further impacting water supplies. Natural resources are important to include in benefit-cost analyses for future projects and may be used to leverage additional funding for mitigation projects that also contribute to community goals for protecting natural resources. Awareness of natural assets can lead to opportunities for meeting multiple objectives. For instance, protecting watersheds will help maintain the quantity and quality of water, timber production and promote carbon sequestration. Future Development Large, destructive fires continue to plague California communities including San Luis Obispo County. Research points out that such impacts are closely related to growth and land-use development, particularly development in the WUI. Out of 5,003 building permits issued in San Luis Obispo County between 2014 and 2019, 15% (737) were for construction in the Very High severity zones, and another 30% (1,516) were within the High severity zone. Additional growth and development in areas of fire risk will continue to increase the exposure of the planning area to damaging wildfires. Risk Summary The overall significance of wildfire in San Luis Obispo County is High. These events are recurring in nature and can cause significant damage, loss of life, and disruption to critical infrastructure. • The Wildfire hazard severity of most of the county is rated as Moderate, High, or Very High. • The county experiences several relatively smaller wildfires per year, with a major damaging fire every 7-8 years. The last several decades have seen a continual increase in the number of fires and acreage burned per year. • Powerlines and vehicle or equipment use account for 70% of ignitions where the cause of the fire can be determined. • Effects on people: Past wildfires in the county have not resulted in a large number of fatalities; however, significant evacuation and sheltering are frequently required. • Effects on property: Wildfires can destroy homes, businesses, and critical infrastructure. Nearly $10 billion dollars’ worth of property is at Very High or High exposure to wildfire threat. • Effects on economy: Wildfires impacts can include loss of property, direct agricultural sector job loss, secondary economic losses to businesses, and loss of public access to recreational resources. • Effects on critical facilities and infrastructure: Wildfires can disrupt access to, or even destroy critical facilities and infrastructure. Based on GIS analysis of the critical facilities and infrastructure, there are a total of 348 of them found within moderate, high, or very high wildfire hazard zones, with most of those facilities in the unincorporated portions of the county. A total of 6 critical scour-condition bridges were found to be in wildfire hazard zones. • Related Hazards: Drought, Agricultural Pest Infestation and Plant Disease, Landslide and Debris Flow ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-296 Table 5-120 Wildfire Risk Summary Jurisdiction Geographic Extent Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Extensive Likely Critical High City of Arroyo Grande Significant Occasional Limited Medium City of Atascadero Extensive Likely Critical High City of Grover Beach Limited Occasional Limited Low City of Morro Bay Extensive Highly Likely Catastrophic High City of Paso Robles Extensive Highly Likely Critical High City of Pismo Beach Significant Occasional Critical Medium City of San Luis Obispo Significant Occasional Limited Medium Avila Beach CSD Significant Likely Limited High Ground Squirrel Hollow CSD Extensive Occasional Critical High Heritage Ranch CSD Extensive Likely Catastrophic High Los Osos CSD Significant Likely Limited High Nipomo CSD Significant Occasional Limited Medium San Miguel CSD Extensive Highly Likely Catastrophic High San Simeon CSD Significant Likely Catastrophic High Templeton CSD Significant Likely Limited Medium Cayucos Sanitary District Significant Occasional Limited Medium Port San Luis Harbor District Significant Occasional Critical Medium San Luis Obispo FCWCD Extensive Likely Critical High South San Luis Obispo Sanitary District Significant Occasional Limited Low ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-297 5.3.16 Hazardous Materials Incidents Hazard/Problem Definition Generally, a hazardous material is a substance or combination of substances which, because of quantity, concentration, or physical, chemical, or infectious characteristics, may either cause or significantly contribute to, an increase in mortality or an increase in serious, irreversible, or incapacitating reversible, illness. Hazardous materials may also pose a substantial present or potential hazard to human health or environment when improperly treated, stored, transported, disposed of, or otherwise managed. Hazardous material incidents can occur while a hazardous substance is stored at a fixed facility, or while the substance is being transported along a road corridor or railroad line or via an enclosed pipeline or other linear infrastructure. The U.S. Department of Transportation (DOT), U.S. Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) all have responsibilities relating to the transportation, storage, and use of hazardous materials and waste. The Right to Know Network (RTK NET), maintained by the EPA’s National Response Center (NRC), is a primary source of information on the use and storage of hazardous materials, as well as data regarding spills and releases. The California Environmental Protection Agency (CalEPA) and Department of Toxic Substances Control (DTSC) are authorized by the U.S. EPA to enforce and implement federal hazardous materials laws and regulations within the state. At the local level, San Luis Obispo County’s Environmental Health Department is the approved CUPA responsible for administration of permitting, inspections, and enforcement for hazardous waste and hazardous materials programs. The CUPA administers the Hazardous Material Business Plan (HMBPs), California Accidental Release Prevention (Cal-ARP) program, and the Aboveground Storage Act, as well as permitting and inspection activities for hazardous waste generators, and onsite hazardous waste treatment facilities, and underground storage tanks. Hazardous materials can be divided into the following classes: • Explosives • Compressed gases: flammable, non-flammable compressed, poisonous • Flammable liquids: flammable (flashpoint below 141 degrees Fahrenheit), combustible (flashpoint from 141 - 200 degrees) • Flammable solids: spontaneously combustible, dangerous when wet • Oxidizers and organic peroxides • Toxic materials: poisonous material, infectious agents • Radioactive material • Corrosive material: destruction of human skin, corrodes steel It is also common to see hazardous materials releases as escalating incidents resulting from other hazards such as floods, wildfires, and earthquakes. The release of hazardous materials can greatly complicate or even eclipse the response to the natural hazards disaster that caused the spill. The Safety Element of the San Luis Obispo County General Plan contains goals, policies, and implementation measures pertaining to hazardous materials, including radioactive materials and pesticides. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-298 Geographic Area Hazmat incidents can occur at a fixed facility or during transportation. Table 5-121 breaks down 1803 hazardous materials incidents reported to the California Office of Emergency Services (Cal OES) Warning Center from 1994 through October 24, 2018 based on location. These incidents include both transportation and fixed-facility incidents. This list in no way captures all hazardous material spills within the county, only those that were significant enough to be reported to Cal OES. The data indicates that hazardous materials incidents can occur across the county with a greater frequency in the more developed areas. Table 5-121 Hazardous Materials Incidents in San Luis Obispo County by Jurisdiction, 1994-2018 Jurisdiction Incidents Jurisdiction Incidents San Luis Obispo City 419 Los Osos 17 Morro Bay 266 Shandon 15 Unincorporated County 209 Pozo 13 Arroyo Grande 161 San Miguel 6 Paso Robles 123 Creston 5 Avila Beach 97 Shell Beach 5 Atascadero 89 Cholame 3 Cambria 62 Cuyuma 2 Nipomo 58 New Cuyuma 2 Pismo Beach 54 Santa Maria 2 Santa Margarita 40 Baywood Park 1 San Simeon 38 Bradley 1 Templeton 26 California Valley 1 Cayucos 24 Camp Roberts 1 Grover Beach 21 Lake Nacimiento 1 Oceano 21 Lockwood 1 Guadalupe 18 Unknown 1 Source: Cal OES Spill Release Reporting (https://www.caloes.ca.gov/cal-oes-divisions/fire-rescue/hazardous-materials/spill-release-reporting), analysis by Wood Fixed Facilities Hazardous materials facilities are identified and mapped by the counties they are located in, along with the types of materials stored there; facilities generally are located in and around developed areas. The San Luis Obispo County Office of Emergency Services administers the Emergency Planning and Community Right-to-Know program for the planning area. Under Chapter 6.95 of the California Health and Safety Code and the Federal Resource Conservation and Recovery Act (RCRA), any business storing quantities of hazardous materials greater than 55 gallons of liquid, 500 pounds of solid or 200 cubic feet of some compressed gasses must file a HMBP annually that establishes incident prevention measures, hazardous material handling protocols and emergency response and evacuation procedures. The EPA requires facilities containing certain extremely hazardous substances to generate Risk Management Plans (RMPs) and resubmit these plans every five years. According to the RTK NET, as of April 2019 there are nine RMP facilities located in the county, as shown below in Figure 5-84. These nine ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-299 sites store approximately 364,066 pounds of toxic chemicals, primarily ammonia (304,000 pounds), chlorine (56,400 pounds), and anhydrous ammonia (28,166 pounds). The California Accidental Release Prevention Program (CalARP) is a statewide initiative to reduce the likelihood and severity of consequences of extremely hazardous materials releases. CalARP requires certain facilities (referred to as "stationary sources") which handle specified chemicals (termed "regulated substances") to take specified actions to proactively prevent and prepare for chemical accidents. Because the CalARP program is implemented at the local government level by the CUPAs, they can work directly with regulated facilities. Figure 5-84 shows 17 CalARP-regulated facilities located in San Luis Obispo County, three of which are also RMP facilities. Additionally, there are several offshore oil and gas drilling platforms to the southwest of Arroyo Grande that have the potential to cause significant oil spills. Finally, California’s only operating nuclear power plant, the Diablo Canyon Nuclear Power Plant, is located in San Luis Obispo County west of Avila Beach. Jurisdictions located in the Emergency Planning Zones (1- 12) for the plant include Avila Beach, the City of San Luis Obispo, Los Osos, Arroyo Grande, Grover Beach, Oceano, Pismo Beach, Shell Beach, Morro Bay, and Cayucos; these zones are shown in Figure 5-85 below. Further details on the Emergency Planning Zones, as well as other information on hazards and vulnerabilities pertaining to the Diablo Canyon Power Plant, can be found in the San Luis Obispo County/Cities Nuclear Power Plant Emergency Response Plan. The plant’s operator, Pacific Gas & Electric, has announced its intention to close both of Diablo Canyon reactors by 2025; however, the site will remain a hazardous materials site for decades. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-300 Figure 5-84 Significant Hazardous Materials Facilities in San Luis Obispo County PACIFIC OCEAN o EPA Risk Management Plan (RMP ) Fa cilities ■ CalARP Regulated Facilities ■ Fa ci lities that are both RMP and CalARP Regulated 0 Diablo Canyon Powe r Plant --t-----t Ra ilroad ---Highway Freeway Lakes Waterways Map compiled 4/2019 ; wood. intended for planning purposes only . Data Source : San Luis Obispo County, US Census TIGER Database , CA Open Data Portal , HIFLD , CalARP, EPA ••• Monterey 0 10 ""'-, ,; '\ <F,~/r,Q,,{ ( Kings Tulare ljf11ir•' 811 ... , ----------------------- Santa Barbara Ventura 20 40 Miles N A Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-301 Figure 5-85 Diablo Canyon Nuclear Power Plant Emergency Planning Zones Source: San Luis Obispo County Transportation In transit, hazardous materials generally follow major transportation routes, including road, rail and pipelines, creating a risk area immediately adjacent to these routes. The county’s transportation network, primarily U.S. Route 101, and State Highways 1, 46, and 166, all have the potential for hazardous material incidents. Railroad lines and airports may also transport hazardous materials. Hazardous materials releases can also result from natural disasters, such as floods or earthquakes that may cause containment systems to fail or affect transportation infrastructure. In summary, hazardous material incidents have the potential to occur in business and industrial areas (where fixed facilities are located) and along transportation corridors. Often these facilities are concentrated in the planning area \ ' + ••• RI PS ROOHHVINmNTEl [M ID-'illT[ rl.lR61a'.JUND51 & GM/! mms MllNltOR ING, IIECi!NUit.l lN'.l.fll>H & ll«PTIUII COOU PACIFIC / 0 t f A I ..... = "lit.EittilllUlllll ll!:!l llli -:5PIOOl,IIIEWBY!l11 -= ll llllfllilll Wfl\'Illf I TII OOllW €01Slll II' 1HH1 HIG!l S<iHIJill ff HI POlll:l1 IUGH Sl:H MOHIJ{)[ING; D£«1Ni!AMJN,Ult1N & IRKEPT IOHI emu Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-302 due to their manufacturing operations. Hazardous material incidents can also occur in agricultural areas; these types of facilities typically use pesticides, fertilizers, and other agricultural chemicals that are harmful to people and the environment. For example, agricultural pesticides and fertilizers are often transported daily around the planning area. Illegal drug operations and dumping sites have also been known to pose a hazardous materials threat. Lastly, information provided by the National Pipeline Mapping System (NPMS) indicate several pipelines conveying gas or hazardous liquids cross the planning area. Pipelines ruptures can result in major spills, or even explosions like the ones in San Bruno in 2010, and Fresno in 2015. The HMPC noted that high- pressure gas and petroleum pipelines to Kern County cross the San Andreas fault. Extent (Magnitude/Severity) Hazardous materials come in the form of explosives, flammable and combustible substances, poisons and radioactive materials. Hazards can occur during production, manufacturing, storage, transportation, use, or disposal. Impacts from hazardous materials releases can include: • Fatalities • Injury • Evacuations • Property damage • Animal fatalities (livestock, fish & wildlife) • Air pollution • Surface or ground water pollution/contamination • Interruption of commerce and transportation Numerous factors influence the impacts of a hazardous materials release, including the type and quantity of material, location of release, method of release, weather conditions, and time of day. This makes it difficult to predict precise impacts. The impact to life and property from any given release depends primarily on: • The type and quantity of material released. • The human act(s) or unintended event(s) necessary to cause the hazard to occur. • The length of time the hazard is present in the area. • The tendency of a hazard, or that of its effects, to either expand, contract, or remain confined in time, magnitude, and space. • Characteristics of the location and its physical environment that can either magnify or reduce the effects of a hazard. CalFire notes several additional factors that can contribute to the impact of hazardous materials releases from a fixed facility or transportation incident: • Solid, liquid, and/or gaseous hazardous materials can be released from fixed or mobile containers either accidentally or on purpose. • The resulting release can last for hours or for days. • The substances released may be corrosive or otherwise damaging over time, and they may cause an explosion and/or fire. • Contamination may be carried out of the incident area by people, vehicles, water, and/or wind. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-303 • Weather conditions will directly affect how the hazard develops. • The micrometeorological effects of buildings and terrain can alter travel and duration of agents. • Shielding in the form of sheltering in place can protect people and property from harmful effects. • Noncompliance with fire and building codes as well as failure to maintain existing fire protection and containment features can substantially increase the damage from a hazardous materials release. The release or spill of hazardous materials can also require different emergency responses depending on the amount, type, and location of the spill incident. As noted above, the county contains a number of facilities that store and use significant quantities of hazardous materials. Additionally, a variety of hazardous materials are transported through the county by highway, rail, and pipelines, all of which are potentially vulnerable to accidental spills. Consequences can vary depending on whether the spill affects a populated area versus an unpopulated but environmentally sensitive area. Potential losses can vary greatly for hazardous material incidents. For even a small incident, there are cleanup and disposal costs. In a larger scale incident, cleanup can be extensive and protracted. There can be deaths or injuries requiring doctor’s visits and hospitalization, disabling chronic injuries, soil and water contamination can occur, necessitating costly remediation. Evacuations can disrupt home and business activities. Large-scale incidents can easily reach $1 million or more in direct damages, with clean-ups that can last for years. Previous Occurrences San Luis Obispo County experiences multiple hazardous materials incidents every month. The vast majority of these incidents are minor with very localized impacts. However, the county also has a history of more serious incidents. On August 10, 1986, a train derailment including three tank cars containing 31,000 gallons of liquid isobutane led to a precautionary evacuation of 3,000 people in Grover Beach and Oceano; fortunately, there were no leaks or explosions, and no injuries from the incident. In the 1990s a massive oil spill caused by decades of seepage from corroded oil pipelines was discovered underneath the town of Avila Beach, the cleanup of which generated more than 6,750 truckloads of contaminated material. On October 3, 2001, an anhydrous ammonia leak developed in a refrigeration system that was being dismantled at a fish handling facility just above the harbor; the incident resulted in the temporary evacuation of an estimated 3,000 people for approximately nine hours and generated significant nationwide media attention. The EPA’s Right-to-Know Network (RTK NET) records 726 hazardous materials incidents in San Luis Obispo County reported to the EPA from 1987 through 2018, an average of 22.7 per year. However, only the most serious spills are reported to the EPA. The Cal OES Warning Center reports 1,803 hazardous materials incidents in San Luis Obispo County from 1994 through October 24, 2018; this works out to an average of 72 incidents per year. Even this total likely excludes a large number of unreported minor spills. Figure 5-86 below shows the number of incidents in San Luis Obispo County reported to Cal OES over the last 25 years. It shows that the number of recorded hazardous materials incidents in the county has increased from an average of fewer than 60 per year in the 1990s to almost 90 in the recent years. This matches hazardous material incidents statewide, which have similarly increased from around 5,000 incidents per year in the 1990s to over 8,000 in recent years. ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-304 Figure 5-86 Hazardous Materials Incidents in San Luis Obispo County, 1994-2018 Source: Cal OES Spill Release Reporting (https://www.caloes.ca.gov/cal-oes-divisions/fire-rescue/hazardous-materials/spill-release-reporting), analysis by Wood The vast majority of hazardous materials incidents have only minimal life safety impacts. Of the 1,803 incidents Cal OES reports in San Luis Obispo County from 1994 through October 24, 2018, only 110 (6%) result in any injuries, fatalities, or evacuations. This translates to an average of 4.4 damaging hazardous materials incidents per year, although as shown in Figure 5-87 the number of these damaging incidents has increased from 2-3 per year in the late 90s to 5-6 per year more recently. In all, Cal OES records 35 fatalities, 61 injuries, and 30 evacuations associated with those incidents, for an average of 1.4 fatalities, 2.4 injuries, and 1.2 incidents requiring evacuations per year. The number of persons killed or injured in hazardous materials incidents has similarly increased over the last 25 years, from around 3 fatalities/injuries per year in the 1990s to 4.5 today. 30 40 50 60 70 80 90 100 SLO Linear (SLO) ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-305 Figure 5-87 Hazardous Materials Incidents in San Luis Obispo County Resulting in Injuries, Fatalities, or Evacuations, 1994-2018 Analysis of the Cal OES data shows a great deal of variation from month-to-month and year-to-year. As shown in Figure 5-88, Hazardous materials incidents are slightly more likely in the winter (6.6 incidents per month on average) and slightly less common in the summer (5.6 incidents per month on average) but occur regularly in all months. Hazardous materials incidents are more common during the daytime hours, as shown in Figure 5-89. Figure 5-88 Hazardous Materials Incidents by Month Source: Cal OES Spill Release Reporting (https://www.caloes.ca.gov/cal-oes-divisions/fire-rescue/hazardous-materials/spill-release-reporting), analysis by Wood 0 2 4 6 8 10 12 70 80 90 100 110 120 130 140 150 160 170 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-306 Figure 5-89 Hazardous Materials Incidents by Time of Day Source: Cal OES Spill Release Reporting (https://www.caloes.ca.gov/cal-oes-divisions/fire-rescue/hazardous-materials/spill-release-reporting), analysis by Wood Figure 5-90 breaks down the incidents reported to RTK NET by type of incident. While fixed site incidents are the largest single category, combining all the transportation-related categories (water vessel, highway, rail, and pipeline) reveals that transportation incidents are far more common than fixed site incidents, at 347 incidents (61%) compared to 223 (39%) for fixed site and storage tank incidents. Figure 5-90 Hazardous Materials Incidents by Type Source: U.S. EPA Right-to-Know Network (http://www.rtk.net), analysis by Wood 0 10 20 30 40 50 60 70 80 90 100 208 175134 63 45 41 23 19 15 Fixed site Water vessel Unknown sheen on water Pipeline incident Railroad non-release Highway Railroad incident Unknown Storage tank incident • • • • • • • • ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-307 Table 5-122 shows the most common substances involved in releases in San Luis Obispo County. Various oils, gasoline, and diesel fuel together account for two-thirds of spills, followed by unknown substances, sulfur dioxide, anhydrous ammonia, and nitric acid. Table 5-122 Most Common Hazardous Materials Substances Released in San Luis Obispo County CHRIS Substances # of Incidents CHRIS Substances # of Incidents OUN: Unknown oil 151 OTD: Oils, fuel: 2-D 17 ODS: Oils: diesel 85 OMN: Oils, miscellaneous: mineral 16 NCC: Unknown / no CHRIS code 81 AMA: Ammonia, anhydrous 11 OIL: Oils: crude 64 NTX: Nitric oxide 10 SFD: Sulfur dioxide 54 ONG: Natural gas 8 Invalid code: Chris Code Left Blank 38 HDZ: Hydrazine 8 OHY: Hydraulic oil 37 OLB: Oils, miscellaneous: lubricating 7 GAS: Gasoline: automotive (unleaded) 33 OTF: Oils, miscellaneous: transformer 7 OTH: Other oil 33 OOD: Oils, fuel: 1-D 5 UNK: Unknown material 19 BSS: Bilge slops 5 OMT: Oils, miscellaneous: motor 18 PCB: Polychlorinated biphenyl 5 Source: U.S. EPA Right-to-Know Network (http://www.rtk.net), analysis by Wood Probability of Future Occurrences As discussed above, the county experiences between 80-90 hazardous materials incidents per year, with an average of 1.4 fatalities, 2.4 injuries, and 1.2 incidents requiring evacuations per year. These incidents have been increasing an average of 5% a year, and there is no reason to think they won’t continue to increase over the next five years. Thus, there is effectively a 100 percent chance that the county will see a hazardous materials incident in any given year. They can occur at any time and with little predictability given the presence of multiple major transportation routes in the planning area, as well as multiple facilities that store and use hazardous materials. Climate Change Considerations There are no known effects of climate change on human-caused hazards such as hazardous material incidents. Vulnerability General Property The impact of a fixed hazardous facility, such as a chemical processing facility is typically localized to the property where the incident occurs. The impact of a small spill (i.e. liquid spill) may also be limited to the extent of the spill and remediated if needed. While cleanup costs from major spills can be significant, they do not typically cause significant long-term impacts to property. People Hazardous materials incidents can cause injuries, hospitalizations, and even fatalities to people nearby. People living near hazardous facilities and along transportation routes may be at a higher risk of exposure, particularly those living or working downstream and downwind from such facilities. For ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-308 example, a toxic spill or a release of an airborne chemical near a populated area can lead to significant evacuations and have a high potential for loss of life. In addition to the immediate health impacts of releases, a handful of studies have found long term health impacts such as increased incidence of certain cancers and birth defects among people living near certain chemical facilities. However there has not been sufficient research done on the subject to allow detailed analysis. Social Vulnerability While hazardous material incidents could take place anywhere across the county and may be unpredictable, those living near HazMat facilities or along transportation routes that additionally happen to be socially vulnerable would be of highest concern. Based on a combination of the SoVI data presented and discussed in subsection 4.4.1 and the presence of major transportation routes and EPA or CalARP regulated facilities the most vulnerable populations include Paso Robles, Atascadero, San Luis Obispo, Arroyo Grande, Grover Beach, Oceano and Nipomo. In addition, agricultural workers are most vulnerable to pesticide exposure. Critical Facilities and Infrastructure Impacts of hazardous material incidents on critical facilities are most often limited to the area or facility where they occurred, such as at a transit station, airport, fire station, hospital, or railroad. However, they can cause long-term traffic delays and road closures resulting in major delays in the movement of goods and services. These impacts can spread beyond the planning area to affect neighboring counties, or vice- versa. While cleanup costs from major spills can be significant, they do not typically cause significant long- term impacts to critical facilities. Economy The primary economic impact of hazardous material incidents results from lost business, delayed deliveries, property damage, and potential contamination. Large and publicized hazardous material- related events can deter tourists and recreationists and could potentially discourage residents and businesses. Economic effects from major transportation corridor closures can be significant. Historic, Cultural, and Natural Resources Hazardous material incidents may affect a small area at a regulated facility or cover a large area outside such a facility. Widespread effects occur when hazards contaminate the groundwater and eventually the municipal water supply, or they migrate to a major waterway or aquifer. Impacts on wildlife and natural resources can also be significant. Future Development The amount of hazardous materials that are stored, used, and transported across the county are inferred to continue to increase over the next five years based on regional growth trends. As discussed previously, the number of hazardous materials incidents in San Luis Obispo County has been increasing roughly 5% a year for the last twenty years and is likely to continue to increase. Future development is also expected to increase the number of people potentially exposed to the impacts of hazardous materials incident. 5,003 building permits were issued in San Luis Obispo County between 2014 and 2019; 61% of those were ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-309 within 0.5 mile of a CalARP or RMP hazardous materials facility or transportation route. The following table provides additional details. Table 5-123 Building Permits Issued Near Hazardous Materials Facilities and Transportation Routes, 2014-2019 Building Permits Issued 2014-2019 Number Percentage Total 5,003 100% Within ½ mile of RMP or CalARP Facility 203 4% Within ½ mile of highway hazardous materials route (US 1; State 46, 101, 106) 1,749 35% Within ½ mile of railroad line 862 17% Within ½ mile of airport 238 5% Source: San Luis Obispo County, analysis by Wood Risk Summary The overall significance of hazardous materials incidents in San Luis Obispo County is Medium. These incidents occur frequently with little-to-no warning, both at fixed sites and along transportation routes throughout the county. The possibility of a major spill impacting a major populated area exists, historically the impacts of these incidents on the county as a whole have been fairly limited. • The county experiences between 80-90 hazardous materials incidents per year, with an average of 1.4 fatalities, 2.4 injuries, and 1.2 incidents requiring evacuations per year. These incidents have been increasing an average of 5% a year. • 61% of releases are transportation related, compared to 39% at fixed facilities. • Hazardous materials releases can complicate response to and recovery from natural disasters such as foods and earthquakes. • Effects on people: Hazardous Materials incidents can cause injuries and fatalities, as well as long term health problems like increased cancer risks. • Effects on property: Impacted properties can require cleanup, but the effects are usually localized to the site of the release. • Effects on economy: Extended road closures can result in economic losses and impact tourism. • Effects on critical facilities and infrastructure: Impacted facilities and infrastructure can require cleanup, but the effects are usually localized to the site of the release. • Related Hazards: Earthquake, Flood, Tsunami. Table 5-124 Hazardous Materials Risk Summary Jurisdiction Geographic Extent Probability of Future Occurrence Magnitude/ Severity Overall Significance San Luis Obispo County Limited Highly Likely Negligible Medium City of Arroyo Grande Significant Highly Likely Negligible Medium City of Atascadero Significant Highly Likely Negligible Medium City of Grover Beach Limited Occasional Negligible Low City of Morro Bay Limited Occasional Negligible Medium City of Paso Robles Extensive Highly Likely Negligible Low - ••• Section 5 Risk Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 5-310 Jurisdiction Geographic Extent Probability of Future Occurrence Magnitude/ Severity Overall Significance City of Pismo Beach Limited Likely Limited Medium City of San Luis Obispo Significant Highly Likely Negligible Medium Avila Beach CSD Significant Highly Likely Negligible Medium Ground Squirrel Hollow CSD Limited Occasional Negligible Low Heritage Ranch CSD Limited Occasional Negligible Low Los Osos CSD Limited Occasional Negligible Low Nipomo CSD Significant Highly Likely Negligible Medium San Miguel CSD Significant Likely Negligible Medium San Simeon CSD Limited Highly Likely Negligible Medium Templeton CSD Significant Likely Limited Low Cayucos Sanitary District Limited Unlikely Negligible Low Port San Luis Harbor District Extensive Unlikely Catastrophic High San Luis Obispo FCWCD Significant Highly Likely Negligible Medium South San Luis Obispo Sanitary District Limited Unlikely Negligible Low ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-1 SECTION 6 CAPABILITY ASSESSMENT Thus far, the planning process has identified the hazards posing a threat to San Luis Obispo County and described, in general, the vulnerability of the County to these risks. The next step is to assess what loss prevention mechanisms are already in place. This part of the planning process is the mitigation capability assessment. Combining the risk assessment with the mitigation capability assessment results in the County’s “net vulnerability” to disasters and more accurately focuses the goals, objectives, and proposed actions of this plan. As such, this section presents San Luis Obispo County’s mitigation capabilities: programs and policies currently in use to reduce hazard impacts or that could be used to implement hazard mitigation activities. It also identifies select state and federal departments/agencies that can supplement the County’s mitigation capabilities. This assessment is divided into four sections: regulatory mitigation capabilities, administrative and technical mitigation capabilities, fiscal mitigation capabilities and hazard specific capabilities. Information about capabilities specific to the other participating jurisdictions can be found in the jurisdictional annexes. The HMPC used a two-step approach to originally conduct this assessment for the County. First, an inventory of common mitigation activities was made through the use of a matrix. The purpose of this effort was to identify policies and programs that were either in place, needed improvement, or could be undertaken, if deemed appropriate. Second, the HMPC reviewed existing policies, regulations, plans, and programs to determine if they contributed to reducing hazard-related losses or if they inadvertently contributed to increasing such losses. During the 2019 update, this section was reviewed by County staff and the Wood consultant team to update information where applicable. This update process afforded the County and its participating jurisdictions the opportunity to review their previous capabilities and note the ways in which these capabilities have improved or expanded since the adoption of the previous plan. Additionally, in summarizing their current capabilities and identifying gaps, plan participants also considered their ability to expand or improve upon existing policies and programs as potential new mitigation strategies. Section 7 Mitigation Strategy includes mitigation actions aimed at improving community capability to reduce hazard risk and vulnerability. 6.1 San Luis Obispo County’s Regulatory Mitigation Capabilities Table 6-1 lists regulatory mitigation capabilities, including planning and land management tools, typically used by local jurisdictions to implement hazard mitigation activities and indicates those that are in place in San Luis Obispo County. Excerpts from applicable policies, regulations, and plans and program descriptions follow to provide more detail on existing mitigation capabilities. For each of the profiled hazards, several ordinances, regulations, plans and programs were identified in various communities within County. These are listed here to serve as a reference for related planning efforts. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-2 Table 6-1 San Luis Obispo’s Regulatory Mitigation Capabilities Regulatory Tool (ordinances, codes, plans) Yes/No Comments General Plan Y Agricultural Element, Conservation and Open Space Element, Economic Element, Housing Element, Noise Element, Offshore Energy Element, Parks and Recreation Element, Safety Element; Land Use Element: Framework for Planning – Coastal Zone, and Framework for Planning - Inland Zoning ordinance Y Inland Land Use Ordinance and Coastal Zone Land Use Ordinance (Titles 22 and 23) Subdivision ordinance Y Title 21 Real Property Division Ordinance Growth management ordinance Y Title 26 Floodplain ordinance Y County Land Use Ordinance Section 22.14.060; One foot above base flood elevation freeboard requirement for all structures. Other special purpose ordinance (stormwater, steep slope, wildfire) Y Stormwater Management Chapter 22.10.155; California Fire Code 16.10; Post-Disaster Regulations 19.85; Combining Designation Standards Chapter 23.07; Geologic Study Area (GSA) 23.07.080; Title 22 Grading Ordinance Building code Y Title 19, Chapter 19.03 of County Code. Adopted 2016 California Building Codes: CA Residential Code (2016); CA Plumbing Code (2015 UPC); CA Mechanical Code (2015 UMC); CA Electrical Code (2014 NEC); CA Energy Code (2016); CA Green Building Code (2016); CA Fire Code (2015 IFC); CA Reference Standards Code (2016) Fire department ISO rating Y 6 Erosion or sediment control program Y Erosion and Sedimentation Control Plan Required 22.52.120; 23.05.036 Stormwater management program Y 22.10.155; Post-Construction and During Construction Stormwater Management requirements Site plan review requirements Y Title 22 Article 3 Capital improvements plan Y FY 2019-20 through FY 2023-24 Economic development plan Y Economic Element (2012) of General Plan Local emergency operations plan Y County EOP (2016) Other special plans Y CWPP (2019) Dam and Levee Failure Plan (2016); Tsunami Emergency Response Plan (2016); Earthquake Emergency Response Plan (2015); Hazardous Materials Emergency Response Plan (2013); Disaster Recovery Plan (2018); Diablo Canyon emergency response and evacuation plans; Tsunami evacuation plans; Wildland Fire Pre-attack Plans; Wildland Fire evacuation plans for West Atascadero, Parkhill, Avila, Cambria, Upper Los Berros, Suey Creek. Flood insurance study or other engineering study for streams Y 2012 Elevation certificates (for floodplain development) Y Required by 22.14.060(D)(4). On file with the Public Works Department. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-3 Regulatory Tool (ordinances, codes, plans) Yes/No Comments Other Y Water Efficient Landscaping 19.90; Transfer of Development Credit Program; Fire Safety Plans 22.50; CUPA Program (Hazardous Materials and Waste) Unreinforced Masonry Building Removal program; Community Health Improvement Plan (2018-2023) As indicated in the table above, San Luis Obispo County has several plans and programs that guide the County’s development in hazard-prone areas. Starting with the San Luis Obispo County General Plan, which is the most comprehensive of the County’s plans when it comes to mitigation, some of these are described in more detail below. 6.1.1 San Luis Obispo County General Plan The San Luis Obispo County General Plan consists of multiple element documents (12), as well as two Frameworks for Planning (Inland and Coastal) and four Area Plans. This discussion is derived primarily from four Element documents of the San Luis Obispo County General Plan, from which the text that follows is largely extracted. The County’s General Plan is a comprehensive, long-term framework for the protection of the county’s agricultural, natural, and cultural resources and to direct future development in the county. Designed to meet state general plan requirements, it outlines policies, standards, and programs and sets out plan proposals to guide day-to-day decisions concerning San Luis Obispo County’s future. It is a legal document that serves as the County’s “blue print” or “constitution” for land use and development. The General Plan Policy Document is organized into twelve elements, which generally correspond with the content requirements specified in State Planning Law. The following four elements have goals, policies and implementation measures related to hazards and hazard mitigation and are detailed further below: • Safety Element • Agricultural Element • Conservation and Open Space Element • Land Use Element Each of these elements include goal statements relating to different aspects of the issues addressed in the element. Under each goal statement, the plan sets out policies that amplify the goal statement, policies, and implementation strategies. Implementation strategies are listed and described briefly with the action proposed by the program, the County agencies or departments with primary responsibility for carrying out the program, the time frame for accomplishing the program and potential funding sources. The following is an element-by-element summary of the General Plan goals and policies that are most relevant to the Hazard Mitigation Plan Update. The summary tracks the organization of each element, with topically-focused goals followed by related policies. Safety Element The County concurrently updated the Safety Element of the General Plan during the 2019 update of the HMP, with finalization of the Safety Element anticipated by mid-2020. The information from the Hazard Identification and Risk Assessment of the HMP was used to inform the Safety Element, and the goals and ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-4 policies in both documents were aligned to be coordinated and mutually reinforcing. The document was updated previously in 1999. Planning for growth and development requires the consideration of a wide range of public safety issues. Many of the safety risks associated with development, including risks to buildings and infrastructure, can be avoided through siting decisions made at the planning stages of development, while others may be lessened through the use of mitigation measures in the planning and land use review process. This element outlines San Luis Obispo County’s strategy for ensuring the maintenance of a safe physical environment. Applicable goals and policies from the draft update of the Safety Element (as of November 2019) are presented below. As the HMP was finalized prior to the Safety Element update, the following are subject to change when the Safety Element is finalized in 2020. Emergency Preparedness This section of the Safety Element is specific to preparing for emergencies as well as recovery needs post- disaster. The section also recognizes, “an important part of preparedness is the careful assessment of risks before an emergency occurs (San Luis Obispo County, 1999). The following policies are set forth in the section to help the County achieve its goal of emergency preparedness and are applicable to hazard mitigation. Table 6-2 Emergency Preparedness Goal and Policies Goal 1: Support programs that provide emergency and other services to the public when a disaster occurs. The focus of response activities is saving lives and preventing injury and reducing immediate property damage. Policy 1.1: Coordination. Improve coordination among City, County and State programs, and among others working to reduce the risks of disasters. This should also include improved coordination with the news media. This will result in more effective preparedness, response and recovery from disasters. Policy 1.2: Information Systems and Research. Expand and keep current the database of safety related information. Knowledge about disasters and the area we live in is growing. New information must be made available to the public and decision makers. Regularly update the GIS data as new information becomes available. Policy 1.3: Risk Assessment. Continue investigations that reduce or eliminate long term risks. Risk assessment activities, effectively carried out, can improve the efficiency and reduce the cost of response and recovery from disasters. Geologic and Seismic Hazards ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-5 This section is specific to the various types of geologic and seismic hazards in San Luis Obispo County. Geologic hazards include, slope instability and landslides. Seismic hazards profiled include, fault rupture, ground shaking, and liquefaction and seismic settlement hazards. This section also covers coastal bluff erosion hazards. The purpose of this section is to help in assessing the vulnerability of development to these types of geologic hazards. The following policies set forth in the section are applicable to hazard mitigation and help the County achieve its goal of minimizing the potential for loss of life and property as a result of geologic and seismic hazards. Table 6-3 Geologic and Seismic Hazard Goal and Policies Goal 4: Minimize the level of injury, loss of life and damage to existing and future critical facilities, property and infrastructure due to geologic and seismic hazards. Policy 4-1: Resilient Design. Develop a comprehensive approach to reducing the level of damage and losses due to hazards through utilizing resilient community and critical infrastructure design, management, code enforcement, GIS mapping, improved policies, procedures, training evacuation planning, and planning processes. Policy 4-2: Fault Information. Information on faults and geologic hazards in the County should continue to be updated. The County will enforce the General Plan and applicable building codes that require developments, structures, and public facilities to address geologic and seismic hazards through the preparation and approval of geotechnical and geologic reports. Appointment of a County Geologist will improve implementation of the goals, policies, programs and standards of this Element by assuring more objective review and consistent enforcement of hazard mitigation measures county-wide than is possible under the present system of project review. Policy 4-3: Fault Rupture Hazards. Locate new development away from active and potentially active faults to reduce damage from fault rupture. Fault studies may need to include mapping and exploration beyond project limits to provide a relatively accurate assessment of a fault’s activity. The County will enforce applicable regulations of the Alquist-Priolo Earthquake Fault Zoning Act pertaining to fault zones to avoid development on active faults. Policy 4-4: Reduce Seismic Hazards. The County will enforce applicable building codes relating to the seismic design of structures to reduce the potential for loss of life and reduce the amount of property damage. Policy 4-5: Liquefaction and Seismic Settlement. The County will require design professionals to evaluate the potential for liquefaction or seismic settlement to impact structures in accordance with the currently adopted Uniform Building Code. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-6 Policy 4-6: Slope Instability. The County acknowledges that areas of known landslide activity are generally not suitable for residential development. The County will avoid development in areas of known slope instability or high landslide risk when possible and continue to encourage that developments on sloping ground use design and construction techniques appropriate for those areas. Policy 4-7: Readiness and Response. Fire and law enforcement agencies will maintain and improve their ability to respond to seismic emergencies throughout the County. Policy 4-8: Coastal Bluff. Development shall not be permitted near the top of eroding coastal bluffs. Policy 4-9: Unreinforced Masonry Buildings. Reduce the danger to people and property from unreinforced masonry buildings. Fire Safety This chapter of the Safety Element is specific to fire hazards, including urban fires and wildfire hazards. The Fire Safety chapter acknowledges that fire plays a significant role in the County’s ecosystem and that development patterns can influence a fire agency’s response and ability to defend “values at risk”. The following policies set forth in the chapter are applicable to hazard mitigation and help the County achieve its goal of reducing the threat of fire hazards. Table 6-4 Fire Safety Goals and Policies Goal 5: Mitigate Wildfire hazard impacts to existing and future development. Policy 5-1: Pre-Fire Management. New development should be carefully located, with special attention given to fuel management in higher fire risk areas. Large, undeveloped areas should be preserved so they can be fuel- managed. New development in fire hazard areas should be configured to minimize the potential for added danger. Policy 5-2: Loss Prevention. Improve structures and other values at risk to reduce the impact of fire. Regulations should be developed to improve the defensible area surrounding habitation. Policy 5-3 Limit Development. Limit new development in areas identified as State Responsibility Areas (SRAs) or Very High Fire Hazard Severity Zones in Local Responsibility Areas or other areas determined to have a high wildfire risk. Policy 5-4 Streamline Reviews. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-7 Expedite reviews for reconstruction of fire-damaged structures, while adopting current codes and standards in State Responsibility Areas (SRAs) or Very High Fire Hazard Severity Zones. Policy 5-5 Wildfire Protection Planning. Encourage the development of community wildfire protection plans to supplement existing codes and regulations. Policy 5-6 Expert Review. Include professional fire planning experts and Fire Department in the planning review process for projects located in High and Very High Fire Hazard Areas to consistently evaluate fire safe design, potential impacts related to fire safety, and to identify effective measures to minimize potential impacts related to wildland fire. Policy 5-7 Post-Fire Streamlining. Encourage rapid post-fire assessment and rehabilitation of burned lands to limit soil erosion, protect water quality, minimize flooding, restore damaged landscapes and assist landowners in re- establishing fire-safe homesites. Policy 5-8 Landowner Education. Facilitate education of landowners about the risks of living in the wildland urban interface including regulations, prevention measures and pre-application activities. Water Hazards This chapter of the Safety Element is specific to flood, dam failure, tsunami, and coastal erosion hazards. The following policies and implementation measures set forth in the chapter are applicable to hazard mitigation and help the County achieve its goal of reducing damage caused by water related hazards. Table 6-5 Water Hazards Goal and Policies Goal 7 Mitigate flood hazard impacts to existing and future development. Policy 7.1 Resilient Development and Design. New development or redevelopment shall be sited and designed to avoid or minimize coastal flooding; and shall take into account significant storm events, tidal inundation, and predicted sea level rise over the anticipated life of the development. Policy 7.2 Flood Hazards. Strictly enforce flood hazard regulations both current and revised. FEMA regulations and other requirements for the placement of structures in flood plains shall be followed. Maintain standards for development in flood-prone and poorly drained areas. Policy 7.3: Reduce Flood Damage. Reduce flood damage in areas known to be prone to flooding, such as Los Osos, Avila Valley, Santa Margarita, Cambria, Oceano and others. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-8 Policy 7.4: Floodplain Management. Promote and implement sound floodplain management through continued compliance with the National Flood Insurance Program and consistent implementation of the County Land Use Ordinance Section 22.14.060. Other Safety Issues This chapter speaks to aircraft hazards, radiation hazards, hazardous materials, electromagnetic fields, radon and hazardous trees. The following policies captured are applicable to hazard mitigation and are related to manmade hazards that are profiled in this plan as well as hazardous trees. Table 6-6 Human Caused Hazards Goal and Policies Goal 10: Reduce the potential for harm to individuals and damage to the environment from radiation hazards, hazardous materials, and hazardous trees. Policy 10.1: Radiation Hazards. Maintain a high level of emergency preparedness and information to the public. Policy 10.2: Hazardous Materials. Reduce the potential for exposure to humans and the environment by hazardous substances. Policy 10.3: Hazardous Trees. Reduce the danger to people and property from trees that are weakened and susceptible to falling or limb loss during storms. Agricultural Element This element focuses on the agricultural economy and resources of San Luis Obispo County, “while recognizing that other valuable open space resources such as wetlands, riparian vegetation or scenic resources can exist on those agricultural lands” (San Luis Obispo County, 2010). The policies within the Agricultural Element apply primarily to land designated Agriculture on the County’s land use designation maps. The applicable policy measures from the Agricultural Element are presented below. Table 6-7 Agricultural Element Policies Policies and Implementation Measures Regarding the Use of Agricultural Land Policy AGP9: Soil Conservation. a.Encourage landowners to participate in programs that reduce soil erosion and increase soil productivity. Promote coordination between the Natural Resources Conservation Service, Resource Conservation Districts, Consolidated Farm Services Agency, Morro Bay State and National Estuary, and other agencies and organizations. b.Emphasize the long-range benefits of proper drainage control and tillage, cropping, soil amendment, and grazing techniques to minimize soil erosion. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-9 c. Assure that roads and drainage systems on county-controlled properties and facilities do not negatively impact agricultural lands and that the roads and systems are properly maintained. Loss of topsoil is a threat to the continued productivity of agricultural lands. The purpose of this policy is to minimize the loss of topsoil by encouraging broad-based cooperation between property owners, ag operators, agencies and organizations that will lead to effective soil conservation practices on farmlands and on county-controlled properties. Policy AGP10: Water Conservation. a. Encourage water conservation through feasible and appropriate “best management practices.” Emphasize efficient water application techniques; the use of properly designed irrigation systems; and the control of runoff from croplands, rangelands, and agricultural roads. b. Encourage the U.C. Cooperative Extension to continue its public information and research program describing water conservation techniques that may be appropriate for agricultural practices in this county. Encourage landowners to participate in programs that conserve water. Land area, the water falling on it, and groundwater stored beneath its surface are inseparable in determining agricultural values and productivity in the County. Other than the land itself, water is the most precious resource for agriculture. Conserving water can benefit agriculture by reducing groundwater pumping. Uncontrolled runoff can contribute to soil loss, reduced water quality in streams, increased impact on riparian habitat, decreased opportunity for groundwater recharge and degradation of the general productivity of the watershed. Policy AGP11: Agricultural Water Supplies. a. Maintain water resources for production agriculture, both in quality and quantity, so as to prevent the loss of agriculture due to competition for water with urban and suburban development. b. Do not approve proposed general plan amendments or rezonings that result in increased residential density or urban expansion if the subsequent development would adversely affect: (1) water supplies and quality, or (2) groundwater recharge capability needed for agricultural use. c. Do not approve facilities to move groundwater from areas of overdraft to any other area, as determined by the Resource Management System in the Land Use Element. Policy AGP12: Pest, Vertebrate, and Weed Management. a. Assure that pests such as squirrels and noxious weeds are managed on county owned properties so as to avoid impacts on agriculture. b. Encourage the use of integrated pest management techniques to manage pests, vertebrates, and weeds on both public and private lands. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-10 d. Support and promote programs that help landowners learn pest control methods, utilizing the expertise of the U.C. Cooperative Extension and the County Agriculture Department. Policies Regarding the Protection of Agricultural Lands Policy AGP15: Transfer of Development Credits (TDC) a. Continue to utilize a voluntary TDC program to help protect agricultural resources by guiding development to more suitable areas. Policy AGP26: Streams and Riparian Corridors. a. Encourage private landowners to protect and preserve stream corridors in their natural state and to restore stream corridors that have been degraded. Provide information and incentives to eliminate overgrazing in stream corridors. Encourage off-stream livestock watering sources. b. For new development requiring a discretionary permit and for land divisions, protect streams and riparian habitat affected by the proposal through the following measures: 1. Consistent with the requirements of the Regional Water Quality Control Board’s Basin Plan, establish a grading and building setback of 30 feet from the top of the steam bank. Locate buildings and structures outside the setback. Do not remove riparian vegetation within 30 feet of the top of the stream bank. Provide for adjustments when the applicant demonstrates that such setbacks would have a significant negative impact on the agricultural viability of the site, or where alternatives are infeasible or more environmentally damaging, and the adjustments are acceptable to the Regional Board. 2. Require appropriate erosion control measures during and following construction. 3. Consistent with state and federal requirements, allow steam alterations for water supply and flood control projects, road maintenance, maintenance of existing channels, or improvement of fish and wildlife habitat if there are no practical alternatives. 4. Consistent with state and federal requirements, assure that stream diversion structures protect habitats. 5. When significant impacts to stream or riparian resources are identified, the landowner shall implement county-approved mitigation measures consistent with the existing requirements of CEQA. Conservation and Open Space Element Applicable goals and policies from the Conservation and Open Space Element are presented below. Implementation measures related to each policy can be found in the General Plan. Air Quality ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-11 This chapter focuses on local and regional air quality and sets forth goals and policies for the County to reduce its contribution to global climate change. Table 6-8 Air Quality and Climate Change Adaption Goal and Policies Goal AQ 5: The County will adapt to adverse climate change. Policy AQ 5.1: Adapt to Climate Change. Identify needs and strategies to monitor, prepare for, and adapt to a changing climate. Policy AQ 5.2: Public Awareness. Increase public awareness about climate change and lifestyle changes that will reduce greenhouse gas emissions. Biological Resources This chapter identifies biological resources of importance for the County and puts forth a framework to achieve a “future that is healthy and vibrant ecologically, socially and economically. Table 6-9 Biological Resources Goals and Policies Goal BR 2: Threatened, rare, endangered, and sensitive species will be protected Policy BR 2.7: Fire Suppression and Sensitive Plants. Balance the need for fire suppression and/or vegetation (fuel) management with the need to protect sensitive biological resources. Where possible, design land divisions and development so that fuel-breaks, vegetation, or fuel modification areas that are needed to reduce fire hazards do not disrupt special-status plant communities or critical habitat for special status animal species. Fuel-breaks and vegetation or fuel modification areas shall be located on the development side of required setbacks from sensitive features and shall be in addition to the required setbacks. Policy BR 2.11: Control Spread of Non-native Invasive Animal Species. The County will work with landowners, the California Department of Fish and Game, the U.S. Fish and Wildlife Service, the National Marine Fisheries Service, the National Invasive Species Council, and other agencies and organizations to control and prevent the spread of non-native, invasive animal species. Goal BR 3: Maintain the acreage of native woodlands, forests and trees as 2008 levels. Policy BR 3.1: Native Tree Protection. Protect native and biologically valuable trees, oak woodlands, trees with historical significance, and forest habitats to the maximum extent feasible. Policy BR 3.2: Protection of Native Trees in New Development. Require proposed discretionary development and land divisions to avoid damage to native trees (e.g., Monterey Pines, oaks) through setbacks, clustering, or other appropriate measures. When avoidance is not feasible, require mitigation measures. Policy BR 3.4: Vegetation and Wildlife Disease Management Programs. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-12 Continue to support agency programs to limit the impacts of Sudden Oak Death syndrome and any other potential or existing diseases harmful to native vegetation and wildlife in the county, while addressing any potential adverse effects on sensitive resources. Goal BR 4: The natural structure and function of streams and riparian habitats will be protected and restored Policy BR 4.2 Minimize Impacts from Development. Minimize impacts of public and private development on streams and associated riparian vegetation due to construction, grading, resource extraction, and development near streams/ Policy BR 4.3 Alluvial Well Extractions. Require discretionary projects that depend on alluvial well extractions and stream diversion to monitor the long-term effects on surface streamflow and riparian vegetation. Identify and implement contingencies for maintaining streamflow (e.g., minimum bypass flows, alternate water sources, decreased pumping rates, groundwater discharge). Policy BR 4.5 Encourage Stream Preservation on Private Lands. Encourage private landowners to protect and preserve stream corridors in their natural state and to restore stream corridors that have been degraded. Policy BR 4.6 Encourage Stream Preservation on Public Lands. Protect stream and riparian corridors in their natural state on public lands. Policy BR 4.10 Vector Control. Control vectors to prevent disease problems in keeping with good conservation principles. Vector control practices should minimize disturbance of the environment. Goal BR 7: Significant Marine Resources will be protected. Policy BR 7.1: Coastal Protection. The County should continue to advocate sound energy and coastal protection policies and oppose proposals along the San Luis Obispo County coastline that are inconsistent with the County’s Local Coastal Program and other County plans and policies. Policy BR 7.3: Best Management Practices. Support landowners that participate in education and assistance programs and other voluntary and cooperatives programs, such as conservation programs offered by the Natural Resources. Policy BR 7.7: Watershed Protection. As a complement to regulatory and enforcement programs, promote a voluntary, cooperative, educational, and incentive-based approach to protect Morro Bay and its watershed. Where appropriate, continue to obtain open space easements for sensitive wetlands and bayfront areas, and encourage other agencies and conservation organizations to obtain open space and conservation easements and fee title to these areas Energy ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-13 This chapter set goals, policies and implementation measures related to the energy sector in the County and ensure future energy development is done responsibly and sustainably. The following goals and policies are applicable to hazard mitigation. Table 6-10 Energy Goals and Policies Goal E 4: Green building practices will be integrated into all development. Policy E 4.4: Solar Exposure. Orient new buildings to maximize solar resources, shading, ventilation, and lighting. Goal E 7: Design, Siting, and Operation of non-renewable energy facilities will be environmentally appropriate. Policy E 7.1: Non-Renewable Energy Facility Siting. Energy, fossil fuel and related facilities will be sited, constructed and operated in a manner to protect the public from potential hazards and significant environmental impacts. Policy E 7.3: Safety Coordination. The County will coordinate with state and federal agencies to promote an information exchange about safety standards and regulations with regard to electricity and fossil fuel facilities. Policy E 7.4: National Repository for Nuclear Waste. Carefully monitor the federal government’s progress in establishing a national repository for high-level nuclear waste and the state’s efforts for low-level nuclear waste disposal. The County should advocate the safest methods of transportation and storage. Open Space Resources This chapter set goals, policies and implementation measures to ensure the protection, restoration, and preservation of significant open features throughout San Luis Obispo County. Table 6-11 Open Space Resources Goal and Policy Goal OS 1: Important open space areas will be identified, protected, sustained and where necessary, restored and reclaimed. Policy OS 1.1: Future Open Space Protection. Continue to identify and protection open space resources with the following characteristics: •Recreation areas, •Ecosystems and environmentally sensitive resources such as natural area preserves, streams, and riparian vegetation, unique, sensitive habitat, natural communities’ significant marine resources, •Archaeological, cultural, and historical resources, •Scenic areas, •Hazard areas, •Rural character ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-14 Soil Resources This chapter set goals, policies and implementation measures to ensure the protection, restoration, and preservation of significant open features throughout San Luis Obispo County. Table 6-12 Soil Resources Goals and Policies Goal SL 1: Soils will be protected from wind and water erosion, particularly that caused by poor soil management practices. Policy SL 1.2: Promote Soil Conservation Practices in All Land Uses. Require erosion and sediment control practices during development or other soil- disturbing activities on steep slopes and ridgelines. These practices should disperse stormwater so that it infiltrates the soil rather than running off and protect downslope areas from erosion. Policy SL 1.3: Minimize Erosion Associated with New Development. Avoid development, including roads and driveways, on the steeper portions of a site except when necessary to avoid flood hazards, protect prime soils, and protect sensitive biological and other resources. Avoid grading and site disturbance activities on slopes over 30%. Minimize site disturbance and protect existing vegetation as much as possible. Goal SL 2: Watershed and ecological function will be maintained through soil conservation. Policy SL 2.1: Protect Watersheds and Aquifer Recharge Areas. Give high priority to protecting watersheds, aquifer-recharge areas, and natural drainage systems when reviewing applications for discretionary development. Water Resources This chapter set goals, policies and implementation measures that connect water supply and land use planning in the County that will ensure a sustainable water supply. Table 6-13 Water Resources Goals and Policies Goal WR 1: The County will have a reliable and secure regional water supply (IRWM). Policy WR 1.1: Protect water supplies. Continue to coordinate with water suppliers and managers to identify water management strategies to protect existing and secure new water supplies. Policy WR 1.2: Conserve Water Resources Water conservation is acknowledged to be the primary method to serve the county’s increasing population. Water conservation programs should be implemented countywide before more expensive and environmentally costly forms of new water are secured. Policy WR 1.3: New Water Supply. Development of new water supplies should focus on efficient use of our existing resources. Use of reclaimed water, interagency cooperative projects, desalination of contaminated groundwater supplies, and groundwater recharge projects should be considered prior to using imported sources of water or seawater desalination, or dams and on-stream reservoirs. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-15 Policy WR 1.4: Use Reclaimed Water. The County will be a leader in the use of reclaimed water. Support expanding the use of reclaimed water to make up at least 5% of total water use by 2015 and 10% of total water use by 2020. Policy WR 1.5: Interagency Projects. Help implement interagency projects, including emergency interties between systems, jointly developed facilities, water exchanges, and other methods of enhancing reliability through cooperative efforts. Policy WR 1.7: Agricultural Operations. Groundwater management strategies will give priority to agricultural operations. Protect agricultural water supplies from competition by incompatible development through land use controls. Policy WR 1.11: Reduce RMS alert levels. The County will work with local agencies to reduce Resource Management System alert levels for water supply and water systems from recommended or certified Levels of Severity II or III to Level of Severity I or better by 2020. Policy WR 1.12: Impacts of new development. Accurately assess and mitigate the impacts of new development on water supply. At a minimum, comply with the provisions of Senate Bills 610 and 221. Goal WR 2: The County will collaboratively manage groundwater resources to ensure sustainable supplies for all beneficial uses. Policy WR 2.1: Groundwater quality assessments. Prepare groundwater quality assessments, including recommended monitoring, and management measures. Policy WR 2.2: Groundwater basin reporting programs. Support monitoring and reporting programs for groundwater basins in the region. Policy WR 2.3: Well permits. Require all well permits to be consistent with the adopted groundwater management plans. Policy WR 2.4: Groundwater recharge. Where conditions are appropriate, promote groundwater recharge with high-quality water. Policy WR 2.5: Groundwater banking programs. Encourage groundwater-banking programs. Goals WR 3: Excellent water quality will be maintained for the health of people and natural communities. Policy WR 3.6: Prevent pollution of water sources. The County will collaborate with private and nonprofit land managers, Resource Conservation Districts, recreation providers, Community Services Districts, and other stakeholders to prevent pollution or contamination of potable water sources, such as Lake Nacimiento and Lopez Lake. The County will also coordinate with the Nacitone Watershed Plan. Goal WR 4: Per capita potable water use in the county will decline by 20 percent by 2020. Policy WR 4.8: Efficient irrigation. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-16 Support efforts of the resource conservation districts, California Polytechnic State University (CalPoly), the University of California Cooperative Extension, and others to research, develop, and implement more efficient irrigation techniques. Goal WR 5: The best possible tools and methods available will be used to manage water resources. Policy WR 5.1: Watershed approach. The County will consider watersheds and groundwater basins in its approach to managing water resources in order to include ecological values and economic factors in water resources development. Policy WR 5.2: Climate Change. The County will consider ongoing research on long-term changes in climate and precipitation patterns in the county and region and incorporate relevant data in its approach to managing water resources. Goal WR 6: Damage to life, structures, and natural resources from floods will be avoided. Policy WR 6.1: Integrated management. Pursue an integrated management approach for waterway projects that includes flood management, sea level rise, water quality protection, groundwater recharge, and ecosystem enhancement objectives. Policy WR 6.2: Region-wide permitting. The County should coordinate with applicable state, regional, and local permitting agencies to develop and implement a region-wide permitting program that will provide consistent watershed or regional implementation measures. Policy WR 6.3: Drainage problems. Consider drainage problems in the context of an entire watershed. Drainage and flood management plans should address property owner and developer responsibilities. These plans should use an integrated watershed approach that incorporates flood management, water quality, water supply, groundwater, and ecosystem protection and enhancement objectives on a watershed/basin scale. Policy WR 6.7: Areas prone to flooding. Develop a public information and education program in areas of the county prone to flooding and drainage problems to discourage new development in those areas and to inform residents and property owners about how to deal with drainage and flood control problems, use best management practices, and get assistance. Land Use Element The Land Use Element of the County’s General Plan is one of the required general plan elements by the state. The principle consideration in this element is the physical setting of the county. This element describes the official County policy on the location of land uses and ensures orderly growth and development. This element is written in coordination with the circulation element in order to correlate future land use with transportation infrastructure. The policies within the Land Use Element work directly with the County’s Land Use Ordinance to provide comprehensive development standards and review procedures. ___ I ____________ I ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-17 The Land Use Element is divided into four major chapters: Framework for Planning, the area plans, the community/village plans, and the official maps. For planning purposes and due the size and diversity of topography and climate throughout, the county has been divided into the Inland Area and the Coastal Zone. Both of which have separate Framework for Planning documents, area plans, and community plans tailored to those areas of the county. Each Framework of Planning document assists the County Planners when reviewing development or land division proposals by explaining the criteria in applying land use categories, combining designations and the Resource Management System to ensure future growth and development takes places in areas and in a manner that will not harm current or future residents. 6.1.2 Combining Designations Combining designations are special map categories that identify areas of potential hazards or public value that should be taken into consideration when proposing new development and when reviewing applications for development. Each Framework for Planning document explains the purpose of the combining designations with a list of items specific to the Inland Area and Coastal Zone, both explain the following as one of the purposes of the designation, “To reduce risks to life and property through proper location and design of structures within areas subject to man-made or natural hazards, such as: airports; flooding; or geologic hazards, including active faulting, land sliding, or liquefaction.” There are ten (10) combining designations in the Inland Area and fourteen (14) in the Coastal Zone. Each designation has specific purposes and development standards to help mitigate the risk of the hazard for proposed development. The following combining designations are specific to hazards profiled in this plan were taken from the Framework for Planning documents: Geologic Study Area (GSA): Applied to: areas identified in the Alquist-Priolo Geologic Hazard Zones Act as "Special Studies Zone" (Public Resources Code Section 2622); to areas within urban and village reserve lines subject to "moderately high to high" landslide risk or liquefaction potential (as identified in the geologic and seismic hazard section of the Safety Element of the county general plan); and to lands outside urban reserve lines subject to high landslide risk potential (also according to the geologic and seismic hazard section of the Safety Element). Flood Hazard (FH): Applied to flood-prone areas identified through review of available data from various federal, state, or local agencies. Also includes flood elevations of existing lakes and reservoirs. Sensitive Resource Area (SRA): Applied to areas having high environmental quality and special ecological or educational significance. (Note, the following is only applicable in the Coastal Zone): The SRA includes four types of Environmentally Sensitive Habitats: Wetlands, Coastal Streams and Riparian Vegetation, Terrestrial Habitats and Marine Habitats. The following combining designations are only applicable to the Inland Area: TDCS Transfer of Development Credits Sending Site: Applied to areas where a landowner has met the criteria and standards of the Land Use Ordinance for TDC Sending Sites and has entered into an easement that qualifies under either the Open Space Easement Act or the Conservation Easement Act granted to a qualified public or private non-profit organization created for the purposes of protecting and managing resources, that restricts the development potential of the property. May also apply to community-based TDC programs, (as set forth in Chapter 6 of ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-18 Framework for Planning) identified through an area or community/village plan update or by request of the area property owners. [Added 1996, Ord. 2776] TDCR Transfer of Development Credits Receiving Site: Applied to areas where a landowner has met the criteria and standards of the Land Use Ordinance for TDC Receiving Sites and where a tentative map requiring the use of TDCs has been approved and recorded. May also apply to community-based TDC programs, (as set forth in Chapter 6 of Framework for Planning) identified through an area or community/village plan update or by request of the area property owners. [Added 1996, Ord. 2776] 6.2 San Luis Obispo County’s Administrative and Technical Mitigation Capabilities The following County Departments have existing capabilities that are currently being used or could be used in planning for hazard mitigation projects. Other departments not listed here that have hazard specific capabilities are listed under subsection 6.4 Hazard Specific Mitigation Capabilities of this section. Table 6-14 below identifies the County personnel responsible for activities related to mitigation and loss prevention in San Luis Obispo County. 6.2.1 Department of Planning and Building The San Luis Obispo County Department of Planning and Building is the County’s land-based department. This department is responsible for a wide variety of programs and activities related to planning, zoning, permits, water conservation, stormwater, energy and housing for the unincorporated portion of the County of San Luis Obispo. Staff often take natural hazards into consideration when reviewing development applications and updating the County land use plans, as the Department is responsible for applying the County’s Land Use Code, General Plan, and Building Code to each land use and construction permit application. The Department’s mission is to promote “the wise use of land and helping to build great communities”. 6.2.2 Office of Emergency Services The County Office of Emergency Services (OES) coordinates planning and preparedness, response and recovery efforts for disasters occurring within the unincorporated area of San Luis Obispo County. OES has the mission of serving the public before, during and after disasters. The Office communicates and coordinates with all levels of government and many other entities in order to minimize the impact of disasters and enable affected communities to return to pre-disaster conditions as soon as possible. OES is responsible for public outreach related to hazards, including educating the public on preparedness and mitigation actions, this information can be found on the County’s website ReadySlo.org. The Office is also responsible for the public alert and notification systems to notify the public during an emergency. Various emergency plans have been developed and implemented by OES, some of which are described in further detail in subsection 6.4 Hazard Specific Mitigation Capabilities. These emergency plans include: The County Emergency Operations Plan (EOP), Earthquake Emergency Response Plan, Dam and Levee Failure Plan, Hazardous Materials Response Plan, Recovery Plan and Tsunami Response Plan. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-19 6.2.3 Environmental Health Services Division Environmental Health is a division of the County Public Health Department with the mission of providing a safe and healthful environment for all unincorporated areas of San Luis Obispo County. The Division maintains geospatial data and utilizes GIS including web map viewers to share information related to the assessment of proposed water well sites, beach water quality, and mosquito surveillance trapping sites which include the identification and counts of mosquito species. The Environmental Health Division also provides the following services related to hazards and hazard mitigation: Disaster Preparedness and Emergency Response Program – The Division is responsible for providing information related to water quality, food safety, sewage disposal, indoor air pollution, fire recovery and cleanup and other guidance that can be leveraged to protect public health during a disaster or emergency. Land Use Program – A required review by the Division with referral from the Planning and Building Department. The purpose of the program is to prevent health hazards and mitigate, where possible environmental degradation as a result of improperly planned development projects. The primary focus is water quality and availability. CUPA Program (Hazardous Materials and Waste) – The Environmental Health Division is the County’s Certified Unified Program Agency (CUPA) which applies the state regulatory standards and programs related to hazardous materials. Refer to subsection 6.4 and the Hazardous Materials Capabilities subsection for more information related to the specific programs with the County’s CUPA Program. 6.2.4 Public Works Department The San Luis Obispo County Public Works Department is comprised of twelve divisions. The Department has the overall responsibility for the maintenance of all county roadways and bridges, engineering review of proposed land developments, the administration and operation of various water and waste water facilities, long term master water planning, and the facility planning, design, and construction management of all County building projects. The Public Works Department is also charged with the development and implementation of the County’s five-year Capital Improvement Plan. Table 6-14 San Luis Obispo County’s Administrative and Technical Mitigation Capabilities Personnel Resources Yes/No Department/Position Planner/engineer with knowledge of land development/land management practices Y Planning and Building Department/Planning and Engineering Staff Engineer/professional trained in construction practices related to buildings and/or infrastructure Y Planning and Building Department/Building Staff Planner/engineer/scientist with an understanding of natural hazards Y Public Works, Planning and Building Department, Ag Department/Planning, Engineering, and Environmental Specialist Staff Personnel skilled in GIS Y Information Technology Department/GIS Analysts Full time building official Y Planning & Building Department/Chief Building Officer ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-20 Personnel Resources Yes/No Department/Position Floodplain manager Y Public Works/Water Resources Engineer Emergency manager Y Office of Emergency Services/Emergency Services Coordinator Grant writer Y Office of Emergency Services/ Emergency Services Coordinator; Planning and Building Department/Planning Staff; Public Works/Engineering Staff; Public Health/Program Managers; Environmental Health Services/Program Managers Other personnel Y County Health Officer, Public Health Dept. GIS Data Resources (Hazard areas, critical facilities, land use, building footprints, etc.) Y Information Technology Department/GIS Analysts; Ag Commissioner, Assessor’s Office; Environmental Health, Planning and Building, Public Works Warning Systems/Services (Reverse 9-1-1, cable override, outdoor warning signals) Y Reverse 9-1-1; Early Warning System Sirens; Emergency Alert System; Wireless Emergency Alerts, NOAA Weather Radio; Social Media; Route Alerting Other Y Subdivision Review Board; Evacuation Assistance List and Registration; Fire Safe Council; County Drought Task Force; Resource Management Administration; CUPA Program 6.2.5 Local Boards, Commissions, Committees There are a number of local boards, commissions, and committees in San Luis Obispo County. Those that have responsibilities related to hazard mitigation are described briefly below. • Board of Supervisors – The Board of Supervisors (BOS) is the legislate body of the County responsible for setting policies and priorities that serve the County’s needs. The BOS is made up of five members who are each elected by five districts of approximately equal population to overlapping four-years terms. The BOS holds bi-weekly televised broadcasts of Board meetings to reach and inform as many citizens as possible. • Planning Commission - This commission is charged with the review and approval or denial of discretionary land use permits. The Commission is also advisory to the Board of Supervisors on proposed amendments to the General Plan and the Zoning Ordinance. • Agricultural Liaison Advisory Board (ALAB) – This advisory board to the Board of Supervisors is the forum for the discussion of local agricultural and land use matters as directed by the Board of Supervisors. The ALAB board is comprised of the following members: one representative from each Supervisorial district; SLO County Farm Bureau representative; Agricultural Finance representative; Environmental representative; Coastal San Luis Resource Conservation District (RCD) representative; Upper Salinas-Las Tablas RCD; SLO County Cattleman’s Association Representative; Wine Grape industry representative; Vegetable industry representative; Nursery industry representative; Organic ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-21 Grower/Direct Marketing industry representative; Strawberry industry representative. As well as non- voting members include the UC Cooperative Extension Director and Agricultural Commissioner/Sealer. • Parks and Recreation Commission (PRC) – An advisory group providing a link between Parks and Recreation Department, member of the County Board of Supervisors and the public. All five members are individually appointed by the Board member representing their district. The PRC advises Staff and the Board of Supervisors on park development issues, budget considerations, and community relations. • Water Resources Advisory Committee (WRAC) – The WRAC advises the County Board of Supervisors on all policy decisions relating to the water resources of the San Luis Obispo County Flood Control and Water Conservation District. The Committee recommends specific water resource and water conservation programs, methods of financing water resource programs, and other programs concerning the objectives and purposes of the San Luis Obispo County Flood Control and Water Conservation District Act. 6.2.6 State and Federal Programs A number of state and federal programs exist to provide technical and financial assistance to local communities for hazard mitigation. Some of the primary agencies/departments that are closely involved with local governments in the administration of these programs include: • California Governor’s Office of Emergency Services – State of California Multi-Hazard Mitigation Plan • California Governor’s Office of Planning and Research • California Polytechnic State University (Cal Poly) • California Department of Water Resources • California Department of Forestry and Fire Protection • California Environmental Protection Agency • California Department of Fish and Game • California Department of Transportation (Caltrans) (District 5) • California Highway Patrol • California State Parks and Recreation Department • California State Lands Commission • Federal Emergency Management Agency (Region IX) • U.S. Army Corps of Engineers (Sacramento District/Los Angeles District) • Bureau of Reclamation (South-Central California Region) • USDA Forest Service (Los Padres National Forest) • California State Farm Service Agency (Templeton) • National Parks Service • USDA Natural Resources Conservation Service (Templeton Field Office) • U.S. Environmental Protection Agency (Region IX) • American Red Cross (Central California Region) Other resources that are present that could assist in disaster recovery include: • California Military Department – California National Guard Camp San Luis Obispo and Camp Roberts ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-22 6.3 San Luis Obispo County’s Fiscal Mitigation Capabilities Table 6-15 identifies financial tools or resources that the County could potentially use to help fund mitigation activities. Table 6-15 San Luis Obispo County’s Fiscal Mitigation Capabilities Financial Resources Accessible/Eligible to Use (Yes/No) Comments Community Development Block Grants Potentially The County is recipient agency under a variety of CBDG programs. Grants received under programs are restricted to specific uses. The County could potentially apply for any hazard mitigation CDBG program. Capital improvements project funding Potentially The County maintains reserves for capital projects. Use of reserves is subject to Board approval but could potentially be used for hazard mitigation. Authority to levy taxes for specific purposes Unlikely Tax measures must be placed on ballot by BOS majority and if proceeds are dedicated to specific purposes are subject to supermajority (2/3) voter approval Fees for water, sewer, gas, or electric services Potentially BOS can approve fees when a nexus exists to the payor receiving direct benefit Impact fees for new development Potentially BOS can approve fees when a nexus exists to the payor receiving direct benefit Incur debt through general obligation bonds Unlikely Measures for tax-supported debt issuances must be placed on ballot by BOS majority and if proceeds are dedicated to specific purposes are subject to supermajority (2/3) voter approval Incur debt through special tax bonds Unlikely Measures for tax-supported debt issuances must be placed on ballot by BOS majority and if proceeds are dedicated to specific purposes are subject to supermajority (2/3) voter approval Incur debt through private activities No Withhold spending in hazard prone areas No ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-23 6.4 Hazard Specific Mitigation Capabilities The following San Luis Obispo County capabilities are organized by the hazards they help to mitigate. 6.4.1 Adverse Weather Capabilities In San Luis Obispo County, the County Agriculture Department works with growers following inclement weather however at this time does not alert growers of impending severe weather such as freeze, high winds and heavy rains. 6.4.2 Agricultural Pest Infestation and Plant Disease Capabilities Pest Detection Program The pleasant climate and the diversity of crops and landscape plants that appeal to residents of San Luis Obispo County also appeal to invasive and destructive insect pests and plant diseases. In 2012, over 4,800 San Luis Obispo County residents volunteered to help departmental staff search for exotic, destructive insects and pests that can spread plant diseases by participating in the pest detection trapping program. Over 3,900 traps were placed and moved in and out of yards throughout the county. Traps for exotic insects such as Mediterranean, Oriental, Mexican and Melon Fruit Flies, Asian Citrus Psyllid (ACP), Gypsy Moth, Japanese Beetle, Glassy-winged sharpshooter (GWSS) and Light Brown Apple Moth (LBAM) were checked 29,010 times by Pest Detection Trappers from the Agricultural Commissioner’s office. This partnership with residents resulted a successful 2012 trapping season, with only LBAM found in localized quarantine areas in Los Osos and Cayucos. Insect traps were placed in plant nurseries throughout the county for the detection of GWSS, LBAM, ACP and European Pine Shoot Moth. These 228 additional traps were checked 3083 times throughout the trapping season. Pest Detection Trappers placed 1700 traps in commercial vineyards for the detection of European Grapevine Moth (EGVM) and in croplands for the detection of LBAM. These traps were checked 12,224 times. None of the targeted insects were intercepted in the vineyard or cropland traps. Eradication efforts in Northern California have been successful in eliminating the threat of EGVM spreading to San Luis Obispo County. Pest Exclusion Program In order to protect agriculture and the environment from the introduction of pests that do not currently occur in San Luis Obispo County, staff intercepted, inspected, quarantined, excluded and destroyed incoming plant shipments infested with various kinds of harmful pests originating from across the United States and around the world. During 2012, of the 12,004 plant shipments held for inspection, 4,206 shipments were visually inspected and 51 were rejected for significant pest finds or other violations of California regulatory requirements. Staff also examined 4,185 nursery shipments that originated from outside of the county, visually inspecting all but the lowest risk shipments for the presence of the glassy-winged sharpshooter. Due to the success of this statewide program, only one shipment arriving into San Luis Obispo County in 2012 was found to be infested with the Glassy-winged sharpshooter. This thorough inspection program has prevented the Glassy-winged sharpshooter from becoming established in our county, despite large populations in the southernmost portions of the state. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-24 One small infestation within the city of San Luis Obispo in late 2010 has been contained and no additional insects have been detected since insecticide treatments in 2011. If no additional glassy-winged sharpshooters are detected during the 2013 growing season, this pest will be declared eradicated from San Luis Obispo County. Pest Eradication Pest eradication is designed to eliminate small populations of invasive pests that have become established in the county. Rapid response and long-term consistent follow-up are critical to an effective pest eradication project. Depending on the pest type, location and the technology available, an eradication plan may include mechanical, cultural, chemical, or biological means. Regardless of the technique, eradication efforts are generally long-term commitments. Public Education and Outreach efforts The San Luis Obispo County Fire Safe Council has issued articles and brochures on Sudden Oak Death and Pine Pitch Canker, both diseases that increase the potential for catastrophic fires. The San Luis Obispo County Agricultural Commissioner’s office and the University of California Cooperative Extension Farm Advisors keep agriculturalists, including production nursery operators, updated on efforts to prevent, detect and manage or eradicate agricultural pests. 6.4.3 Biological Agents (Naturally Occurring) Capabilities Public Health Department The County Health Officer (CHO) is authorized under the California Health and Safety Code to take measures as may be necessary to prevent the spread of communicable disease. Generally, actions may include: 1) Obtaining information pertaining to the incident, 2) Assessing the health risk to the community, 3) Notifying appropriate agencies, and 4) Coordinating disease prevention and control with community, local, regional, state and federal agencies. Should it be necessary, the CHO may also initiate isolation and/or quarantine measures within the county. Enhanced disease surveillance, including accurate, reliable and timely disease reporting and investigation are crucial to early detection of a naturally occurring infectious disease. The Public Health epidemiologist routinely investigates and records the causes and distribution of disease and disability within the County. Use of the existing centralized reporting system will help ensure coordinated and timely epidemiological investigation of disease occurrence. 6.4.4 Coastal Storm Capabilities Development along the San Luis Obispo County coast is regulated by the standards and policies established in the Coastal Zone Land Use Ordinance (Title 23). All proposed development applications on the coast is reviewed in coordination by the Coastal Commission and the County Planning and Building Department. Development is not permitted near the top of eroding coastal bluffs. San Luis Obispo County will require coastal bluff erosion studies to determine the rate of erosion and the resulting safe distance from the top of the bluff for development. 6.4.5 Dam Failure Capabilities Dam and Levee Failure Evacuation Plan (2016) ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-25 The Dam and Levee Failure Evacuation Plan is an annex to the County’s Emergency Operations Plan and contains information specific to the actions that will need to be taken in the event of a dam or levee failure. The Plan sets forth guidelines and checklists for initial and general emergency management response, and EAS warning message specific to each dam and levee identified in the plan. The Evacuation Plan also include a hazard assessment in which it describes the area dams and levees and the overall potential effects of each one failing. 6.4.6 Drought and Subsidence Capabilities San Luis Obispo County Flood Control and Water Conservation District The San Luis Obispo County Flood Control and Water Conservation District is administered by the County Board of Supervisors and Department of Public Works to address various water related issues in the County including flood control (described in more detail below under Flood Capabilities and in Annex S) and water resources management. The District is responsible for collecting and monitoring data from stream and rain gauges, groundwater wells, and reservoirs to support the County’s water resource planning efforts. The District manages both regional planning efforts for groundwater, watershed and water infrastructure resiliency, and for specific operations such as the Nacimiento Water Project, State Water Project, Lopez (Zone 3) System, and Los Osos Wastewater Recycling Facility. During the 2015 drought the District provided community resources describing water restrictions and tips for conserving water. The Water Resources Advisory Committee (WRAC) advises the County Board of Supervisors on water resources policy decisions related to the District including determining needs and financial capabilities. The WRAC also recommends specific water resource and water conservation programs and methods of financing those programs to the County Board of Supervisors. Regional Water Management Group (RWMG) The San Luis Obispo County methods of financing water resource programs (RWMG) is a collaboration of twenty-nine local agencies and nonprofit organizations responsible for developing and implementing the Integrated Regional Water Management (IRWM) plan. IRWM planning efforts are intended to address all aspects of water resources in the San Luis Obispo County region. The RWMG is comprised of various stakeholder groups that include incorporated cities, community service districts, special districts, nonprofit organizations, water purveyors, resource conservation districts, and other water resources stakeholders. The County Flood Control and Water Conservation District serves as the lead agency. The RWMG is currently in the process of updating the 2014 IRWM Plan, which will also include future updates to the County’s Stormwater Resource Plan (2018). The IRWM Plan, originally developed in 2005, was updated in 2014 to include more information related to water supply and drought events. The IRWM Plan identifies priority issues in the region and sets forth projects and programs to achieve the plans goals and objectives. The Plan is approved by the California Department of Water Resources and each participating member of the RWMG is responsible for adopting the Plan in order to eligible to receive future State grant funding. Countywide Water Conservation Program In response to a multi-year statewide drought and declining water levels in the Nipomo Mesa Water Conservation Area (part of the Santa Maria Groundwater Basin), Los Osos Groundwater Basin and the Paso Robles Groundwater Basin, the County Board of Supervisors adopted Resolution 2015-288 on ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-26 October 27, 2015 to establish the Countywide Water Conservation Program (CWWCP). The program was created to assist with water conservation within these basins. A key strategy of this program is to ensure all new construction and new or expanded agriculture will offset its predicted water use on other properties with in the same basin. Each groundwater basin and conversation area have specific policies and programs to assist residents in meeting the offset requirements. Some of the programs include the cash for grass program, plumbing retrofit program, and a new construction program. The passing of Resolution 2015-288 also led to the adoption of several specific amendments related to water natural new development and water waste prevention within the following documents and ordinances: • The Agricultural Element; • The Conservation and Open Space Element; • Title 8 (Health and Sanitation Code); • Title 19 (Building and Construction Code); • Title 22 (Land Use Ordinance); and • Ordinance 3274 (County Fee Schedule) Groundwater Sustainability Plans and Ground Water Sustainability Agencies The 2015 Sustainable Groundwater Management Act (SGMA) is a comprehensive State law that sets the framework for a statewide, long-term sustainable groundwater management by local entities. Under SGMA, the California Department of Water Resources (DWR) designated priority for groundwater basins throughout the State as either high, medium, low, or very low. There are eight local priority groundwater basins and subbasins (collectively, “basins”) identified in San Luis Obispo County: Paso Robles, Atascadero, Arroyo Grande, Santa Maria, Los Osos, Warden Creek, San Luis Obispo Valley, and Cuyama Valley. SGMA requires that high or medium priority basins are required to form Groundwater Sustainability Agencies (GSAs) consisting of one or more local public agencies overlying the basin. GSAs must develop and adopt Groundwater Sustainability Plans (GSPs) to set forth strategies that will result in long-term groundwater sustainability. High or medium priority basins that are subject to critical conditions of overdraft must submit adopted GSPs by January 31, 2020. High and medium priority basins that are not subject to critical conditions of overdraft must submit adopted GSPs by January 31, 2022. GSAs have been established for each high and medium priority basin in the County and are in the process of developing their GSPs. The GSAs for the Paso Robles and Cuyama basins (both high and subject to critical conditions of overdraft) are anticipated to complete and adopt their respective GSPs by the end of 2019. The GSAs for the San Luis Obispo Valley basin (high and not subject to critical conditions of overdraft) are anticipated to complete and adopt their GSP by the end of 2021. SGMA does not apply to the portions of the Los Osos and Santa Maria basins that are under adjudication, and as a result these basins (including fringe areas outside of the adjudicated areas) are designated very low priority. The Warden Creek, Arroyo Grande, and Atascadero basins are designated very low priority following the recent boundary modification and prioritization processes. As a result, these five basins are no longer subject to the requirements of SGMA. 6.4.7 Earthquake Capabilities The Great California ShakeOut, 2018 The Great California ShakeOut is an annual statewide earthquake drill to prepare citizens on what actions to take in the event of an earthquake. On October 18th, 2018 at 10:18 a.m. individuals throughout San Luis ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-27 Obispo practiced Drop, Cover and Hold on and stayed in that position for 60 seconds, as if a large earthquake had just occurred. The goal of the drill is to prepare California for major earthquakes and inform citizens on what to do before, during and after an earthquake. The California ShakeOut is held the third Thursday of October and every year local governments and individual citizens have the opportunity to participate. The 2019 Great California ShakeOut will take place on October 17th; approximately 3,044 participants in San Luis Obispo County are registered to participate in 2019. Earthquake Emergency Response Plan (2015) San Luis Obispo County Earthquake Emergency Response Plan is a component of the County’s Emergency Operations Plan and establishes the procedures, policies and organizational response to an earthquake event that affects the county. Similar to other emergency response plans in the county the most applicable section to hazard mitigation is the hazard assessment section. This section identifies past earthquake events that have affected the county and describes each active or potentially active faults that are capable of producing damaging earthquakes. Within this section the Plan also identifies the potential effects of a damaging earthquake including secondary hazard events such as hazardous materials incidents, nuclear power plant failure and dam failure. Uniform Code for Building Conservation – Title 19 In 1987 The California legislature passed Senate Bill 547, which required all cities and counties located in Seismic Zone 4, which the County of San Luis Obispo is part of, to conduct an inventory of potentially hazardous structures, including unreinforced masonry buildings. To comply with the requirements of SB 547, the County of San Luis Obispo adopted the Uniform Code for Building Conservation as part of Title 19 (Building and Construction Ordinance) of the County Code. Surveys that were conducted to identify potentially unsafe unreinforced masonry buildings identified about 80 structures that required modifications to meet specified earthquake resistance structural standards. Identified structures that require seismic retrofit are generally located in various areas, mostly urban. The County’s ordinance implementing SB 547 requires the owners of identified unreinforced buildings to demolish the structures or complete modifications, depending upon the building’s use and number of occupants. As of June 2018 only four structures remain on the URM registry (See details in subsection 5.3.7). 6.4.8 Flood Capabilities National Flood Insurance Program (NFIP) The goals of the NFIP are to reduce future flood damage through floodplain management, and to provide people with flood insurance. Community participation in the NFIP is voluntary. The County has participated in the NFIP since 1975. The County and municipalities continue to maintain full compliance with the NFIP. The ways in which each municipality and the County participate in the NFIP are described in further detail in the Flood section of the HIRA section and each jurisdiction’s annex. Continued compliance is also described in Section 7 Mitigation Strategy. Specifics on flood insurance policies and repetitive loss properties are described in 5.3.8. The County is taking action to: •Strictly enforce flood hazard regulations both current and revised. FEMA regulations and other requirements for the placement of structures in flood plains shall be followed. •Maintain standards for development in flood-prone and poorly drained areas. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-28 • Establish mitigation for new development impacts on flooding. • Identify areas known to be prone to flooding, such as Los Osos, Avila Valley, Santa Margarita, Cambria, Oceano and Templeton by developing community drainage studies. Seek stakeholder involvement in developing funding mechanisms and in acquiring grants to implement listed flood control improvements. • Fire, Public Works, and law enforcement agencies will maintain and improve their ability to respond to water hazard emergencies throughout the County. • Outline the needs for mapping of high-risk areas of the County. • Participate in the flood insurance program. Develop Flood Control Zones and assessment districts to finance capital projects and provide for on- going maintenance of facilities and waterways. Community Rating System (CRS): An additional indicator of floodplain management capability is the active participation of local jurisdictions in the CRS. The CRS is an incentive-based program that encourages counties and municipalities to undertake defined flood mitigation activities that go beyond the minimum requirements of the NFIP, adding extra local measures to provide protection from flooding. All of the 18 creditable CRS mitigation activities are assigned a range of point values. As points are accumulated and reach identified thresholds, communities can apply for an improved CRS class. Class ratings, which run from 10 to 1, are tied to flood insurance premium reductions. As class ratings improve (decrease), the percent reduction in flood insurance premiums for NFIP policy holders in that community increases. The cities of Morro Bay and San Luis Obispo participate in the CRS, though the five other incorporated cities and County do not. The San Luis Obispo County Land Use Ordinance and Coastal Zone Land Use Ordinance (Titles 22 and 23 of the County Code) The Land Use Ordinance for the Inland Area and Coastal Zone provide standards for the preparation and submittal of drainage plans for new development. These regulations specify when drainage plans are required, the contents of an adequate drainage plan, drainage standards, and the plan review and approval process. The Land Use Ordinance for both areas of the county contains the County’s Floodplain Ordinance, which specifies development standards for areas that have a Flood Hazard (FH) combining land use designation. The development standards contained in the Floodplain Ordinance pertain to land use permit processing and construction standards for new development located in areas that have the potential to be inundated by a 100-year flood. Flood Control and Water Conservation District The San Luis Obispo County Flood Control and Water Conservation District (District) was established in 1945 with the purpose "to provide for control, disposition and distribution of the flood and storm waters of the district and of streams flowing into the district..." In 1968, Resolution No. 68-223 was adopted and defined the policy role of the District relating to the costs of planning, design, construction, operations and maintenance of drainage and flood control facilities. In accordance with Resolution 68-223, the District cannot be responsible for direct funding of community specific mitigation improvements. The District uses its general funding to identify flooding problems, recommend solutions, and help local areas implement recommended solutions. The District has developed a model on how to approach these important water resource issues, including steps on how to integrate solutions for multiple benefits and community acceptance. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-29 In 2016, the District Board of Supervisors adopted Resolution No. 2016-281 to update the 1968 policy, including provisions related to financing for implementation projects with respect to changes in California law such as Proposition 218. The policy update also includes identifying the broad range of services provided or anticipated to be provided by the District to help achieve sustainable water resources in all areas of the County. The District, through the County Public Works Department, develops flood control projects that could protect life and property from flood hazards through community involvement and establishing funding mechanisms. The District has the authority to maintain and construct flood control improvements on major drainage facilities located throughout the County when specific flood control zones are established. The District has a regional role in the County and can work with individual cities or communities when requested. More information on the District can be found in Annex S. 6.4.9 Hazardous Materials Capabilities Hazardous Materials Emergency Response Plan (2013) The San Luis Obispo County Hazardous Materials Emergency Response Plan provides information related to the response and responsibilities of county departments in the event of a hazardous materials incident. The Plan is written with the intent that it will be read and learned prior to hazardous materials emergency. CUPA Program The Environmental Health Division under the County of San Luis Obispo Public Health Department is the County’s Certified Unified Program Agency (CUPA) which applies the state regulatory standards and programs related to hazardous materials. The following are there are seven (7) hazardous materials programs under the County’s CUPA Program: • Aboveground Petroleum Storage Tank Program • California Accidental Release Prevention Program • Hazardous Materials Business Plan Program • Hazardous Waste Generator Program • Household Hazardous Waste Disposal • Tiered Permitting Hazardous Materials/Waste Program Permit • Underground Storage Tank Program Public Outreach and Education The County Office of Emergency Services (OES) in collaboration with Pacific Gas & Electric (PG&E) produce an annual Emergency Planning Calendar that is mailed to businesses and residences within the Diablo Canyon Emergency Planning Zone as well as available to view online. The calendar provides the following information: • How to prepare for a potential emergency at the Diablo Canyon Power Plant, • what to do during an emergency, public alert and notification system, • What to do if you hear the warning sirens, evacuation information, • School relocation information, • Sheltering place information, • Possible effects to agricultural products in the region, ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-30 • A map and explanation of the emergency planning zones, • An explanation of government response and contacts information. The calendar also provides information for those you do not have transportation to evacuate as well as an “Evacuation Assistance Card” to be filled out and returned to OES by individuals who are unable to evacuate themselves due to a disability or medical need. 6.4.10 Landslide Risk Reduction Capabilities The California Building Code, which has been adopted by all seven cities and the County of San Luis Obispo, requires that site specific investigations be performed for development located in hillside areas. Investigations and practices typically required for hillside development include the following: • Conduct thorough geologic/geotechnical studies by qualified geotechnical engineers and engineering geologists. • Require both engineering geologists and geotechnical engineers during construction to confirm preliminary findings reported during initial studies. • Require certification of the proposed building site stability in relation to the adverse effects of rain and earthquakes prior to the issuance of building permits. • Mandate coordination between the civil engineer and the project engineering geologist and geotechnical engineer during construction grading. • Require mitigation of on-site hazards caused by grading that may affect adjoining properties, including erosion and slope instability. The County acknowledges that areas of known landslide activity are generally not suitable for residential development. The County will avoid development in areas of known slope instability or high landslide risk when possible and continue to encourage that development on sloping ground use design and construction techniques appropriate for those areas. More stringent slope stability criteria, or dynamic stability analysis, may apply to improvement design under the jurisdiction of some agencies. 6.4.11 Tsunami Capabilities County programs related to tsunamis include: working with Federal and State agencies to better understand and prepare for the hazard of tsunamis and to improve the ability to respond to tsunami warnings provided by NOAA’s West Coast and Alaska Tsunami Warning Center. March 25th-29th, 2019 was Tsunami Week in San Luis Obispo County. This was an opportunity for the County to share information with the people and organizations on how to prepare for and understand the warning signs of a tsunami event. During this week the National Weather Service conducted a test of the Emergency Alert System (EAS) and NOAA Weather Radio All Hazards. As of 2019 the County is installing Tsunami evacuation signage as a result of the implementation of an action in the 2014 version of this HMP. Tsunami Emergency Response Plan (2016) This Plan is an annex to the County’s Emergency Operations Plan and contains information specific to the actions that will need to be taken in the event of being notified of a possible tsunami or in the event of an actual tsunami along the County’s coastline. Section two of the Response Plan is the Hazard Assessment ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-31 which includes analysis on the hazard potential, inundation mapping, and potential warning challenges in the event of a tsunami. 6.4.12 Wildfire Capabilities CAL FIRE/San Luis Obispo County Fire Unit Strategic Fire Plan (2018) The County’s Fire Unit Strategic Fire Plan assess the fire situation within the SLO County Fire Unit and explains the preparedness and firefighting capabilities within each division of the Fire Unit. The development of the Plan included local stakeholders to help identify priorities and strategic areas for pre- planning and fuel treatment. The Unit Fire Plan is updated annually and is developed to work cohesively with the CAL FIRE/San Luis Obispo County Fire Departments Service Level Analysis and the California Fire Plan. The Plan identifies six (6) Planning Areas to facilitate localized pre-fire planning efforts and explain priority WUI areas within the Planning Areas that would benefit from fuel reduction or pre-fire planning efforts. The Plan further identifies pre-fire management strategies and tactics for each Planning Area. Pre-fire management strategies are, “all activities undertaken by county land managers, property owners, agencies and fire departments to reduce the risk of wildfire and resulting suppression costs…” (CAL FIRE, 2018). These management strategies focus on the four functions within the County Fire Unit which include, fire prevention (fire codes, design, construction and engineering practices for planning a fire safe community), engineering and structure ignitability, fire information and education and vegetation management. The pre-fire management tactics the Plan identifies are tactics employed by CAL FIRE/SLO through multiple scalable programs to be implemented countywide or at the community level. These tactics include opportunities for fire prevention and engineering tactics which can be integrated into existing planning mechanisms such as the County General Plan, County Municipal Code and Building Plans Reviews and Inspection Program. Appendix A of the Plan lists all CAL FIRE/SLO County Fire Unite Pre-Fire Projects including the Planning Area, status, estimated completion date, project type and net acres. The comprehensive information provided in the CAL Fire/San Luis Obispo County Fire Unit Plan helps to inform other pre-fire planning efforts including county and municipality CWPPs, Fire Danger Operating Plan, County Fire Service Level Analysis, Central Coast Operating Plan, and Wildland Pre-Attack Plans. Community Wildfire Protection Plan (CWPP) (2019) The overall goal of the San Luis Obispo County’s Community Wildfire Protection Plan is to “provide a county level strategic planning level framework for hazardous fuel assessment and reduction within San Luis Obispo County so that structures and assets are provided additional protection, reducing the potential of ignition” (San Luis Obispo, 2019). The plan addresses fire protection efforts to minimize the risk to watersheds, communities, assets, firefighters and the public throughout the County. The CWPP was developed to work together with the California Fire Plan and in collaboration and coordination with the San Luis Obispo County fire agencies, County Fire Council and various stakeholders. The plan identifies strategic measures to reduce vulnerabilities, public education and outreach strategies, and identifies fuel reduction goals and techniques while recognizing the variation in fuels, weather, topography, community and agency priorities throughout the County. The CWPP discusses Cooperative Assistance between the County fire agencies and list existing the automatic and mutual aid agreements between fire agencies. The CWPP is a living document that is managed and updated routinely by the fire agencies and Fire ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-32 Council. The County’s CWPP serves as the foundation document for all local community wildfire protection plans and their wildfire mitigation projects set forth in those plans. Firewise Communities The Firewise USA® program provides a framework for communities to learn how to adapt to living with wildfire, including providing a framework for neighbors in a community to work together and be empowered to reduce risks to wildfire at the local level. The following communities in the County of San Luis Obispo that are certified Firewise communities. •Ranchita Estates, Arroyo Grande •Cambria •Lake Nacimiento, Paso Robles •Heritage Ranch HOA, Paso Robles In addition to the communities listed above, Cabrillo Estates a community in Los Osos met with Cal Fire/SLO County Fire Department and SLO County Fire Council to discuss becoming a Firewise Community. Fire Prevention Ordinances Several local ordinances direct fire prevention activities within San Luis Obispo County. These include Chapter 19.20, Construction Standards of Title 19, of the County Code; as well as Section 22/23.05.050 of the Land Use Ordinance and Coastal Zone Land Use Ordinance. These sections of Titles 22 and 23 contain standards pertaining to the preparation and review of fire safety plans, fire safety standards, site access, and driveway requirements. In addition, the California Fire Code has been adopted by San Luis Obispo County with amendments as part of County Ordinance Title 16. California Fire Code This code may be adopted by local jurisdictions, with amendments, and provides minimum standards for many aspects of fire prevention and suppression activities. These standards include provisions for access, water supply, fire protection systems, and the use of fire-resistant building materials. California Health and Safety Code and the California Building Code The Health and Safety Code provides regulation pertaining to the abatement of fire related hazards. It also requires that local jurisdictions enforce the California Building Code, which provides standards for fire resistive building and roofing materials, and other fire-related construction methods. Title 19 of the California Code of Regulations: These regulations pertain to fire prevention and engineering measures for State Fire Marshal regulated occupancy. Public Resources Code and Title 14 of the California Code of Regulations: The Public Resources Codes (PRC) 4290 and 4291 are State laws that have a significant impact on the prevention of large losses of life and property in the wildland/urban intermix areas from a destructive wildfire. The intent of these codes is to require new development in wildfire prone areas to be built with adequate road access, water for firefighting, addressing, fire resistive construction, and vegetation clearance. The code also requires the owners to maintain an adequate defensible space around their buildings from an approaching fire. These ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-33 laws are an important component in the land use approval process in the County as well as in enforcement by the fire department. Assembly Bill 337 (Bates Bill) In response to the Oakland Hills fire of 1991, this bill was passed in 1992 and requires brush clearance and fire-resistant roof material (Class A or B) to be used on all new construction that is located in areas designated as being a “Very High Fire Hazard Severity Zone”. This applies mostly to the unincorporated areas; Atascadero is the only city in the County that has an area designated as a Very High Fire Hazard Severity Zone. San Luis Obispo County Community Fire Safe Council In addition to the measures outlined above to prevent and best respond to fires, the County has undertaken a variety of mitigation activities including an aggressive inspection program, a Countywide Community Fire Safe Council, a vegetation management program, completing the removal of fuel through a chipping program, creation of community separators and pre-planning major wildfire scenarios in the high and very high fire danger areas (includes evacuation plans and pre-plans). Fires impact an array of agencies, organizations and citizens known as stakeholders. These stakeholders are represented on the San Luis Obispo County Community Fire Safe Council. The purpose of the Council is to bring these representatives to the table to discuss solutions for the prevention and reduction of losses from fire. The primary objective and purpose of the San Luis Obispo County Community Fire Safe Council is to provide education, exchange information and foster fire prevention and fire safety within the County of San Luis Obispo. The San Luis Obispo County Community Fire Safe Council plays a vital role in the development and implementation and reviews all elements of the Fire Management Plan. This practice ensures buy-in from the stakeholders. Mutual Aid Agreements The California Department of Forestry and Fire Protection (CAL FIRE), U.S. Forest Service (USFS), and the Bureau of Land Management (BLM) have entered into mutual aid agreements for the purpose of wildfire protection in San Luis Obispo County. Mutual aid agreements are reciprocal arrangements in which fire protection agencies share personnel and equipment during emergency situations. Cities and fire protection districts are also participants in various mutual aid and auto aid agreements, including the State Master Mutual Aid Agreement. Existing Fire Protection Services Services to San Luis Obispo County are provided by the California Department of Forestry and Fire Protection (CAL FIRE) under contract to provide full service fire protection. CAL FIRE is responsible for the administration of the fire stations that serve the unincorporated areas of the County not within fire protection or other special districts and provides equipment and training for volunteer stations located throughout the county. Risk Reduction Measures A number of steps have been taken by San Luis Obispo County to reduce the potential for wildfires. Although these measures cannot eliminate the risk of wildfire related damages, they will help to ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-34 substantially reduce the associated risk. Wildfire hazard reduction measures generally include implementation by the County of the following precautions: •Use fire resistant building materials and construction methods: Standards have been adopted to reduce the use of combustible building materials in high fire hazard areas. Standards for fire resistive building materials and construction methods are provided by the California Building Code (Chapter 7A), The California Fire Code (Chapter 47) and the Public Resources Code. •Provide defensible space around structures: This broad measure as implemented in the County includes a number of specific actions that are taken to minimize wildfire risks. Providing a defensible space area around a structure serves a dual function of limiting fuel for the fire to approach the structure, as well as providing a position from which fire fighters can combat the blaze. Wildfire risk reduction and management practices enforced in the County include the removal or thinning of highly combustible vegetation, the use and maintenance of fire-resistant plantings, providing clearings around structures and other combustible materials, and the implementation of a variety of other fuel reduction and fire prevention/ suppression measures. •Provide adequate water supply: Water that is used for fire suppression purposes, and the pressure under which it is delivered, is referred to as “fire flow.” The fire flow that would be required for a specific development is dependent upon a variety of factors, including the type of construction, the use or occupancy of the structure, and the location of surrounding structures. For residential development, the County determines adequate fire flow ranges to be a minimum of 1,000 gallons per minute at 20 psi, for a minimum of two hours. •Provide adequate access: Adequate access to structures includes providing roadways that are passable by large fire-fighting equipment. This requires roadways to have adequate widths, as well as gradients, bridges, and turn-around areas that accommodate fire trucks. 6.4.13 Climate Change Capabilities The County has acknowledged that climate change is occurring and has continued to plan for it. The County’s mitigation strategy in Section 7 has two climate change related mitigation actions that are continuing from the previous mitigation action plan: •C.7.2 (formally 10.D) Support Efforts to reduce greenhouse gas emissions. •C.7.4 (formally 10.B) Continue to promote energy efficiency and renewable energy within the County to reduce peak load demand. The HMPC gave the following updates for these actions related to energy efficiency, renewables and energy storage and other efforts: Energy Efficiency •Implemented two phases of the Sustainable Turnkey Solutions project with PG&E, which is estimated to reduce County energy consumption by over ten percent. •Implemented exterior lighting energy efficiency project at El Chorro Park. •Implemented personal computer power monitoring software on Public Works’ computers. •Implementing two lighting energy efficiency projects at 1087 Santa Rosa in SLO and at the Los Osos Sheriff Substation. (current status: ordering equipment for installation) •Developing mechanical energy efficiency projects at three Park sites •Auditing fourteen sites for energy efficiency opportunities to consider for next fiscal year. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-35 Renewable & Energy Storage • Implemented ground-mounted solar photovoltaic system at Creston Fire Station. • Approved two Energy Service Agreements for solar photovoltaic carport canopies at Dept. of Social Services and dairy Creek Golf Course parking lots. (current status: preconstruction) • Audited ten sites for renewable energy and energy storage opportunities. • Developing solar photovoltaic systems and battery storage projects at six County sites (County Operations Center, Los Osos Wastewater Treatment Plant, Lopez Water Treatment Plant, Nacimiento booster stations) Other • Implemented software that allows for tracking energy use at County facilities. • Trained five departments to date (Auditor-Controller-Treasurer-Tax Collector-Public Administrator, Parks and Recreation, Public Works, Drug and Alcohol Services, Planning & Building) • Installing electrical submeters in downtown San Luis Obispo campus to track energy use by building (status: preconstruction) • Formed County-wide stakeholder group to direct energy initiatives Many of these County-facility projects were initiated and initially managed by the Department of Planning & Building’s Energy Section but are now overseen and directed by the Department of Public Works Facilities Division. Other departments in the County have also made steps to educate the public on the potential effects of climate change. The County Public Health Department conducts public outreach through pamphlets and brochures on how climate change may lead to increased vulnerabilities related to community health. 6.5 Opportunities for Enhancement The 2019 update provided the County an opportunity to review and update the capabilities currently in place to mitigate hazards. This also provided an opportunity to identify where capabilities could be improved or enhanced. Specific opportunities could include: Join the CRS: The County may consider joining the Community Rating System to improve flood insurance affordability, public flood hazard notification, and enhanced floodplain management. The County is already going above and beyond some of the minimum NFIP standards by requiring a one foot above base flood elevation freeboard requirement for all new structures permitted in flood hazard areas. The County can get credit for this and potentially lower the cost of flood insurance for residents in the unincorporated areas. A mitigation action specific to exploring the cost/benefit of the CRS has been added to this plan’s mitigation strategy. Become a Tsunami Ready Community: The County is in process of becoming tsunami ready as of 2019. This has been a work in progress, and requires overcoming issues with installing signage within Caltrans encroachments. Training: Provide training opportunities to help inform County staff on how best to integrate hazard information and mitigation projects into their departments. Encourage Additional Firewise Communities: San Luis Obispo County Fire/Cal Fire could continue to help the number of Firewise communities grow and build resilience to wildfires. ••• Section 6 Capability Assessment San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 6-36 Alignment of General Plan Safety Element and related polices with SB 2911 and SB 1241 and pending Cal FIRE Fire Hazard Severity Zone map updates: Recent state legislation is requiring additional fire safe building practices, and pending changes/updates in the Cal Fire FHSZ maps may impose additional requirements in areas potentially prone to wildfire. Effective January 2019 SB 2911 requires parcels in Very High Severity Zones to have fire safe design. The County should review updated maps and update policies to align with the new legislation. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-1 SECTION 7 MITIGATION STRATEGY DMA Requirement §201.6(c)(3): [The plan shall include] a mitigation strategy that provides the jurisdiction’s blueprint for reducing the potential losses identified in the risk assessment, based on existing authorities, policies, programs and resources, and its ability to expand on and improve these existing tools. This section describes the mitigation strategy process and mitigation action plan for the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan. It describes how the County and participating jurisdictions met the requirements for the following from the 10-step planning process: •Planning Step 6: Set Goals •Planning Step 7: Review Possible Activities •Planning Step 8: Draft an Action Plan The mitigation strategy reflects the results of the collaborative work of the HMPC. Subsection 7.3 Mitigation Action Plan is based on the updated planning process, risk assessment, capability assessment, goal setting, and the identification of mitigation actions 7.3. Taking all of these into consideration, the HMPC developed the following overall mitigation strategy: •Communicate the hazard information collected and analyzed through this planning process as well as HMPC success stories so that the community better understands what can happen where and what they themselves can do to be better prepared. •Implement the action plan recommendations of this plan. •Use existing rules, regulations, policies, and procedures already in existence. Given the flood hazard in the planning area, an emphasis should be placed on continued compliance with the National Flood Insurance Program and participation by all communities in the Community Rating System. •Monitor multi-objective management opportunities so that funding opportunities may be shared and packaged, and broader constituent support may be garnered. 7.1 Goals and Objectives DMA Requirement §201.6(c)(3)(i): [The hazard mitigation strategy shall include a] description of mitigation goals to reduce or avoid long-term vulnerabilities to the identified hazards Up to this point in the planning process, the HMPC has organized resources, assessed hazards and risks, and documented mitigation capabilities. The resulting goals, objectives, and mitigation actions were developed based on these tasks. The HMPC held a series of meetings and exercises designed to achieve a collaborative mitigation strategy as described further throughout this section. Over a series of meetings during the 2019 update process the HMPC reviewed the results of the hazard identification, vulnerability assessment, and capability assessment update. This analysis of the risk assessment identified areas where improvements could be made and provided the framework for the HMPC to update planning goals and objectives and the ultimate mitigation strategy for the San Luis Obispo County planning area. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-2 Goals were defined for the purpose of this mitigation plan as broad-based public policy statements that: • Represent basic desires of the community; • Encompass all aspects of community, public and private; • Are nonspecific, in that they refer to the quality (not the quantity) of the outcome; • Are future-oriented, in that they are achievable in the future; and • Are time-independent, in that they are not scheduled events. Goals are stated without regard to implementation. Implementation cost, schedule, and means are not considered. Goals are defined before considering how to accomplish them so that they are not dependent on the means of achievement. Goal statements form the basis for objectives and actions that will be used as means to achieve the goals. Objectives define strategies to attain the goals and are more specific and measurable. During the 2013-2014 planning process, the HMPC validated the goals and objectives from the 2005 plan. During the 2019 plan update process, HMPC members review the existing goals and objectives as well the goals and objectives from each element of the County General Plan as well as the goals and objectives from each participating jurisdiction’s previous hazard mitigation plan. The committee decided to delete the 2014 plan’s goals 5, 6 and 7 which were as follows: • Goal 5 - Minimize the level of damage and losses to people, existing and future critical facilities and infrastructure due to wildland fires. • Goal 6 - Minimize the level of damage and losses to people, existing and future critical facilities and infrastructure due to geological events (earthquakes, landslides, and liquefaction). • Goal 7 - Minimize the level of damage and losses to people, existing and future critical facilities and infrastructure due to tsunami events. The primary reason was to move away from hazard-specific goals. With the deletion of the three goals the remaining goals were renumbered and, in some cases, revised completely. Based on the risk assessment review and goal setting process, the HMPC identified the following goals and objectives, which provide the direction for reducing future hazard-related losses within the San Luis Obispo County planning area. The updated goals and objectives of this plan are: Goal 1 – Promote understanding and support for hazard mitigation by key stakeholders and the public within San Luis Obispo County. Objective 1.1: Educate key stakeholders and the public to increase awareness of hazards and opportunities for mitigating hazards Goal 2 – Mitigate hazard impacts to existing and future development. Objective 2.1: Limit new development in hazard areas, and as permissible, build to standards that will prevent or reduce damage. Goal 3 – Build and support local capacity to address, and commitment to minimize, San Luis Obispo County’s vulnerability to potential hazards through collaboration with the incorporated cities and special districts. Objective 3.1: Improve existing capabilities to manage emergency situations. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-3 Objective 3.2: Enhance the safety of the community. Objective 3.3: Assure that at-risk populations and those with access and functional needs (AFN) are addressed in all plans and procedures. Objective 3.4: Identify and collaborate on hazard mitigation projects that benefit multiple jurisdictions. Goal 4 – Minimize the level of injury and loss of life and damage and to existing and future critical facilities, property and infrastructure due to natural hazards. Objective 4.1: Enhance the ability of community assets so as to minimize damages sustained from potential hazards. Objective 4.2: Develop a comprehensive approach to reducing the level of damage and losses due hazards through utilizing resilient community and critical infrastructure design, management, code enforcement, GIS mapping, improved policies, procedures, training evacuation planning, and planning processes. Objective 4.3: In order to better protect life and property, acquire and develop more accurate, comprehensive countywide GIS data sets. Objective 4.4: Minimize impacts from dam inundation. Goal 5 – Minimize human morbidity and mortality as a result of biological agent threats. Objective 5.1: Curtail the entry and spread of infectious diseases within San Luis Obispo County. Goal 6 – Minimize the extent of damage and destruction to forests, crops, farm animals, humans, and existing and future facilities as a result of agricultural pests and disease. Objective 6.1: Curtail the entry of harmful agricultural pests into San Luis Obispo County. Objective 6.2: Quickly detect and eradicate pathogenic pests within the County. When eradication is not feasible, minimize spread. Goal 7 – Adopt and implement strategies to enable the County to prepare for and adapt to the impacts of climate change through collaboration with the incorporated cities and special districts. Objective 7.1: Minimize the harmful effects of climate change by identifying, assessing and preparing for impacts. Coordinate with the incorporated cities and special districts to implement strategies with regional significance. 7.2 Identification and Analysis of Mitigation Actions In order to identify and select mitigation actions to support the mitigation goals, each hazard identified in Section 5 Hazard and Risk Assessment was evaluated. Only those hazards that were determined to be a priority hazard (high or medium significance ratings) were considered further in the development of hazard-specific mitigation actions. DMA Requirement §201.6(c)(3)(ii): [The mitigation strategy shall include a] section that identifies and analyzes a comprehensive range of specific mitigation actions and projects being considered to reduce the effects of each hazard, with particular emphasis on new and existing buildings and infrastructure. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-4 These priority hazards are: • Drought and Water Shortage (high) • Earthquake (high) • Wildfire (high) • Adverse Weather: Thunderstorm/Heavy Rain/Hail/Lighting/Dense Fog/Freeze (medium) • Agricultural Pest Infestation and Disease (medium) • Biological Agents (medium) • Dam Incidents • Flood (medium) • Landslides and Debris Flow (medium) • Tsunami and Seiche (medium) • Human caused: Hazardous Materials (medium) The HMPC eliminated the hazards identified below from further consideration in the development of mitigation actions because the risk of a hazard event in the County is unlikely or nonexistent, the vulnerability of the County is low, or capabilities are already in place to mitigate negative impacts. The eliminated hazards are: • Adverse Weather: High Wind/Tornado • Adverse Weather: Extreme Heat • Subsidence It is important to note, however, that all the hazards addressed in this plan are included in the countywide multi-hazard public awareness mitigation action, or in jurisdictional-specific actions where these hazards may be a higher priority. Once it was determined which hazards warranted the development of specific mitigation actions, the HMPC analyzed viable mitigation options that supported the identified goals and objectives. The HMPC was provided with the following list of categories of mitigation actions, which originate from the Community Rating System: • Prevention: Administrative or regulatory actions or processes that influence the way land and buildings are developed and built. • Property protection: Actions that involve the modification of existing buildings or structures to protect them from a hazard or remove them from the hazard area. • Structural: Actions that involve the construction of structures to reduce the impact of a hazard. • Natural resource protection: Actions that, in addition to minimizing hazard losses, also preserve or restore the functions of natural systems. • Emergency services: Actions that protect people and property during and immediately after a disaster or hazard event. • Public information/education and awareness: Actions to inform and educate citizens, elected officials, and property owners about the hazards and potential ways to mitigate them. At the mitigation strategy meeting the HMPC was also provided with a matrix showing examples of potential mitigation action alternatives for each of the above categories, for each of the identified hazards. The HMPC was also provided a handout that explains the categories and provided further examples. Another reference document titled “Mitigation Ideas” developed by FEMA was distributed to the HMPC ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-5 via an online link. This document lists the common alternatives for mitigation by hazard. The HMPC was also instructed to consider both future and existing buildings in considering possible mitigation actions. As part of the review of mitigation options long term climate change adaptation strategies were also discussed. HMPC members were encouraged to incorporate climate change adaptation measures into the mitigation strategy of their respective jurisdictions utilizing resources and guidance available on the Cal-Adapt website. A facilitated discussion then took place to examine and analyze the options. Appendix B provides the matrix of alternatives considered. Each proposed new mitigation action was written on a large sticky note and posted on flip charts in meeting room underneath the hazard it addressed. 7.2.1 Prioritization Process Once the mitigation actions were identified, the HMPC was provided with several decision-making tools, including FEMA’s recommended prioritization criteria, STAPLEE, to assist in deciding why one recommended action might be more important, more effective, or more likely to be implemented than another. STAPLEE stands for the following: • Social: Does the measure treat people fairly? (e.g., different groups, different generations) Does it consider social equity, disadvantaged communities, or vulnerable populations? • Technical: Will it work? (Is the action technically feasible? Does it solve the problem?) • Administrative: Is there capacity to implement and manage the project? (adequate staffing, funding, and other capabilities to implement the project?) • Political: Who are the stakeholders? Did they get to participate? Will there be adequate political and public support for the project? • Legal: Does the jurisdiction have the legal authority to implement the action? Is it legal? Are there liability implications? • Economic: Is the action cost-beneficial? Is there funding available? Will the action contribute to the local economy? • Environmental: Does the action comply with environmental regulations? Will there be negative environmental consequences from the action? In accordance with the Disaster Mitigation Act requirements, an emphasis was placed on the importance of a benefit-cost analysis in determining action priority. Other criteria used to assist in evaluating the benefit-cost of a mitigation action included: • Does the action address hazards or areas with the highest risk? • Does the action protect lives? • Does the action protect infrastructure, community assets or critical facilities? • Does the action meet multiple objectives (Multiple Objective Management)? • What will the action cost? • What is the timing of available funding? The mitigation categories, multi-hazard actions, and criteria are included in Appendix B: Mitigation Categories, Alternatives, and Selection Criteria. At the mitigation strategy meeting the HMPC used STAPLEE to determine which of the identified actions were most likely to be implemented and effective. With these criteria in mind, team members were given ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-6 a set of four green sticky-dots. The team was asked to use the dots to prioritize projects with the above criteria in mind, essentially voting on the projects. The projects with the most dots became the higher priority projects. This process provided both consensus and priority for the recommendations. Follow-up meetings were held within each jurisdiction to finalize the actions that are part of this plan. Participating jurisdictions were given the leeway to prioritize the actions specific to them, using the previously mentioned criteria. This plan also carries forward many mitigation actions developed during the 2014 planning process. HMPC members and jurisdictional planning teams were asked to review their existing mitigation actions and report on the progress made toward implementation and decide whether and incomplete actions should be carried forward for continued or future implementation or be deleted. In some cases, mitigation actions were adjusted to reflect new situations or priorities. The process of identification and analysis of mitigation alternatives allowed the HMPC to come to consensus and to collectively prioritize recommended mitigation actions. During the voting process, emphasis was placed on the importance of a benefit-cost review in determining project priority; however, this was not a quantitative analysis. Benefit-cost was also considered in greater detail in the development of the Mitigation Action Plan detailed below in subsection 7.3. Specifically, each action developed for this plan contains a description of the problem and proposed project, expected project benefits, the entity with primary responsibility for implementation, a cost estimate, potential funding sources, and a schedule for implementation. Development of these project details for each action led to the determination of a High, Medium, or Low priority for each action. Recognizing the limitations in prioritizing actions from multiple jurisdictions and departments and the regulatory requirement to prioritize by benefit-cost to ensure cost-effectiveness, the HMPC decided to pursue mitigation action strategy development and implementation according to the nature and extent of damages, the level of protection and benefits each action provides, political support, project cost, available funding, and individual jurisdiction and department priority. This process drove the development of a prioritized action plan for the San Luis Obispo County planning area. Cost-effectiveness will be considered in greater detail through a formal benefit-cost analysis when seeking FEMA mitigation grant funding for eligible actions associated with this plan. 7.3 Mitigation Action Plan This action plan was developed to present the recommendations developed by the HMPC for how the San Luis Obispo County planning area can reduce the vulnerability of people, property, infrastructure, and natural and cultural resources to future disaster losses. Over time the implementation of these projects will be tracked as a measure of demonstrated progress on meeting the plan’s goals. DMA Requirement §201.6(c)(3)(iii): [The mitigation strategy section shall include] an action plan describing how the actions identified in section (c)(3)(ii) will be prioritized, implemented, and administered by the local jurisdiction. Prioritization shall include a special emphasis on the extent to which benefits are maximized according to a cost benefit review of the proposed projects and their associated costs. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-7 7.3.1 Progress on Previous Mitigation Actions San Luis Obispo County have been successful in implementing actions identified in the 2014 LHMP Mitigation Strategy, thus, working steadily towards meeting the 2014 plan goals. During the 2019 plan update process the County and participating jurisdictions reported on the status of the 2014 actions through the use of a reporting tool. Each jurisdiction provided input on if the action had been completed, was deferred (not yet implemented, but still relevant for the updated plan), was in progress, or should be deleted. The results are captured in Table 7.1. The 2014 mitigation strategy contained 48 mitigation actions. Of the County’s actions, six have been completed. The majority of these actions present progress on mitigation of the high significance hazards of earthquake and wildfire. Several others action (36) are implemented annually or are currently in progress. Across all jurisdictions, 22 mitigation actions from their previous mitigation plans have been completed and 122 actions are ongoing or in progress. Overall, a total of 32 new mitigation actions were developed for all of the participating jurisdictions in the 2020 Mitigation Strategy for the County of San Luis Obispo. Table 7.1 provides a summary of the mitigation actions from the 2014 Plan that the County has completed. More details on in-progress ongoing and new actions can be found in subsection 7.3.2 and Table 7-2 below. Table 7.1 San Luis Obispo County Mitigation Actions Completed from 2014 Plan ID Corresponding Hazard(s) Mitigation Action Lead Agency Priority Action Status Notes 1.A Multi: ag pest and disease, adverse weather, biological agents, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, tsunami, wildfire, hazmat Through newsletters, advertisements, speaking engagements and other public contacts, educate the general public and key stakeholders on the issues, responsibilities, and current efforts and successes in the area of disaster preparedness. OES - Lead; All Support H OES continues to educate the public and key stakeholders on disaster preparedness through attendance of Operational Area coordination and planning meetings, speaking engagements, and attendance at public events. County OES also promotes emergency preparedness on social media and our webpage, as well as ReadySLO.org. 2.A Multi: ag pest and disease, adverse weather, biological agents, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, Educate the County’s planning staff, administrative staff and elected officials on the importance of keeping current on trends and developments in disaster preparedness. OES - Lead; All Support H OES continually offers training to County staff, organizes exercises, and actively promotes disaster preparedness. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-8 ID Corresponding Hazard(s) Mitigation Action Lead Agency Priority Action Status Notes tsunami, wildfire, hazmat 3.A Multi: adverse weather, wildfire, hazmat, coastal storm, coastal erosion, sea level rise, drought, earthquake, flooding, landslides, subsidence, tsunami Continue to train all new employees and the Sheriff and CAL FIRE supervisors and officers on their roles and responsibilities at the EOC. OES -Lead; CAL - County Fire & Sheriff's Dept H OES continues to train new employees regarding their roles and responsibilities at the EOC and offers EOC tours. 3.B Adverse Weather Develop an SOP or other procedure for guidance on external agency response coordination to winter storm type events. OES-Lead; CAL - County Fire & Sheriff's Dept M Adverse Weather Events Plan was revised in 2015. 5.H Wildfire Adopt and enforce Wildland Urban Interface Building Code standards that emphasize ignition resistant construction. Planning & Building Dept. H Title 24 of the California Code of Regulation addresses WUI requirements within the California Building Code Chapter 7A and within the California Residential Code section R337. The county adopted these codes. 6.A Earthquake Capture most recent earthquake fault line map. Planning & Building Dept. H https://maps.conservation.ca.gov/cgs/#datalist shows Alquist-Priolo Fault Zones data updated in January 2018. 6.C Earthquake Monitor the progress of PG&E as they perform studies on the newly discovered Shoreline fault and updated plans and policies as necessary. OES M The seismic hazard analysis update was completed in 2015. 6.D Earthquake Develop seismic Retrofit of the existing Avila Beach Drive Bridge over San Luis Obispo and seek funding for implementation. Planning & Building Dept. M Project completed 6.G Earthquake; Landslides Continue to improve GIS mapping and tracking efforts by gathering and maintaining relevant GIS data layers and imagery and utilizing the best Planning & Building Dept. M County currently utilizes ESRI software. Our imagery is re-flown on average every 3 years. Also relates to 2014 action 6.A. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-9 ID Corresponding Hazard(s) Mitigation Action Lead Agency Priority Action Status Notes available mapping applications and software. During the 2019 update, the actions from the 2014 Plan were revisited, re-evaluated, and in some cases re-prioritized. During this process several actions were noted as being deferred. One action was deleted. The following action, “Refresh and maintain GIS mapping of residents on Evacuation Assistance List” was determined to no longer relevant to continue forward in the updated plan because of the list already being maintained by the County’s Office of Emergency Services and was decided that GIS mapping would be repetitive and not needed. Many of the participating jurisdictions have also successfully implemented previously identified actions from their respective hazard mitigation plan. Information on each jurisdictions progress of previous mitigation actions, where applicable, and new actions developed can be found in each jurisdictional annex. Continued Compliance with NFIP Recognizing the importance of the NFIP in mitigating flood losses, an emphasis will be placed on continued compliance with the NFIP by San Luis Obispo County and other NFIP participating communities including the cities of Arroyo Grande, Atascadero, Paso Robles, Grover Beach, Morro Bay, Pismo Beach, and San Luis Obispo. As NFIP participants, these communities have and will continue to make every effort to remain in good standing with NFIP. This includes continuing to comply with the NFIP’s standards for updating and adopting floodplain maps and maintaining and updating the floodplain zoning ordinance. Other details related to NFIP participation are discussed in the flood vulnerability discussion in Section 5 and in the capability assessment in Section 6 and the jurisdictional annexes. 7.3.2 Updated Mitigation Action Plan The action plan summarizes who is responsible for implementing each of the prioritized actions as well as when and how the actions will be implemented. Each action summary also includes a discussion of the benefit-cost review conducted to meet the regulatory requirements of the Disaster Mitigation Act. Table 7-2 identifies the updated mitigation actions for the County of San Luis Obispo. Actions specific to other participating jurisdictions are detailed in the jurisdictional annexes. It is important to note that San Luis Obispo County and the participating jurisdictions have numerous existing, detailed action descriptions, which include benefit-cost estimates, in other planning documents, such as general plan elements, community wildfire protection plans and capital improvement budgets and reports. These actions are considered to be part of this plan, and the details, to avoid duplication, should be referenced in their original source document. The San Luis Obispo County planning area also realizes that new needs and priorities may arise as a result of a disaster or other circumstances and reserves the right to support new actions, as necessary, as long as they conform to the overall goals of this plan. The results of the 2019 project identification and prioritization exercise are summarized below in Table 7- 2. Included in the table are actions that are being carried forward from the 2014 plan, which are noted as continuing or deferred projects in the ‘project status’ column. Deferred projects are those that were identified in 2014 but not yet started. Continuing projects are those identified in 2014 that may have been started but either more work remains, or they are annually implemented projects. The actions are grouped ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-10 by corresponding goals of this plan. The jurisdictional annexes contain the detailed action item descriptions respective to each jurisdiction. The summary table can be used for reference during future HMPC meetings to track progress moving forward. There are actions in the table that mitigate impacts to existing as well as new buildings and infrastructure. Actions that mitigate losses to future development are denoted by an ‘*’ in the table. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-11 Table 7-2 San Luis Obispo County Mitigation Actions ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.1.1 Wildfire Work with the San Luis Obispo County Fire Safe Council to conduct fuel thinning and chipping projects in high priority areas. Collaborate with property owners and regulatory agencies in order to utilize prescribed fire on private and state-owned lands in the county. County Fire Less than $10,000 HMA Grants/Staff Time/Dept. Budget High Ongoing In progress; FSCSLO has obtained multiple grants exceeding $5 million currently for fire prevention. Coupled with no less than 29 bills signed into law in 2018, and with multiple Executive Action from the Governor, there has been a significant effort to increase the pace and scale of fuel reduction. Vegetation treatment is likely to increase from several hundred acres per year to several thousand acres per year starting in 2019. C.1.2 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, tsunami, Support and implement education and public awareness programs. OES Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-12 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes wildfire, hazmat C.1.3 adverse weather, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, tsunami, wildfire, hazmat Increase involvement of disadvantaged environmental justice communities in disaster preparedness activities and prioritize programs and improvements that address their needs. Planning & Building Dept.; All Support Little to no cost Staff Time/Dept. Budget High 2019- 2020 Implementation through public engagement efforts for updates to the Safety Element and LHMP C.1.4 Earthquake Increase participation in earthquake preparedness and education activities such as the Great California Shake-Out Campaign. OES Little to no cost Staff Time/Dept. Budget High Annual Annual Implementation; County OES annually promotes the Great California ShakeOut by registering the County as a participant, requesting the County Board of Supervisors to adopt a resolution endorsing the County’s participation in the ShakeOut, conducting a Drop, Cover and Hold On Exercise for the County ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-13 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes downtown government center, and promoting earthquake preparedness on social media, our County webpage, ReadySLO.org and via news release. C.1.5 Tsunami Update the San Luis Obispo County Tsunami Emergency Response Plan and maps. OES Little to no cost Staff Time/Dept. Budget Low Ongoing In progress; Tsunami inundation maps have been updated for the pre-plans and will be re-printed in 2020. The Tsunami Emergency Response Plan revision should be completed in 2020. C.1.6 Tsunami Provide training on changes to tsunami emergency plans and pre- response plans and policies to appropriate agencies. OES Little to no cost Staff Time/Dept. Budget Low Annual Annual Implementation C.2.1* Multi: Drought, flood Continue to implement low impact development standards to reduce storm water runoff and increase groundwater recharge. Planning & Building Dept. Little to no cost Staff Time/Dept. Budget High Annual Annual Implementation C.2.2* Multi: adverse weather, biological agents, coastal storm, coastal erosion, sea level rise, drought, Encourage planning staff to attend seminars and lectures on naturally occurring hazards so that they may better assist the appropriate governing bodies as they process future developments. OES - Lead; All Support Little to no cost Staff Time/Dept. Budget Medium Annual Annual Implementation; The County encourages all staff members to attend trainings, seminars and lectures ensuring up to date understanding of environmental hazards such as, sea-level rise, wildfire and climate change - ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-14 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes earthquake, flooding, landslides, subsidence, tsunami, wildfire allowing for adequate goal and policy development. C.2.3 Multi Through Development Review process, require new developments to incorporate community wildfire protection planning. Planning & Building Dept. Little to no cost Staff Time/Dept. Budget High Ongoing In progress C.3.1 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, tsunami, wildfire, hazmat Support the development of the County Regional Community Emergency Response Team (CERT) in local areas. OES, CAL - County Fire & Sheriff's Dept Little to no cost Staff Time/Dept. Budget Medium Annual Annual implementation; SLO Regional CERT was officially recognized by FEMA in 2019. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-15 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.3.2 Multi: wildfire, earthquake, tsunami, landslides, flooding Emergency Permit Processing/Temporary Housing to allow for mitigation considerations during the disaster recovery process. Planning & Building Dept. $10,000 to $50,000 Staff Time; Dept. Budget; potential post- disaster funding High 5 years NEW. This would include hiring a consultant to assist the county with emergency permit processing post disaster; develop post- disaster permitting procedures and processing; develop a simplified review and plan-check process for reviewing engineering evaluations and proposed repair plans and issuing building permits; decide if building owners will be allowed to place temporary trailers on site; educate staff of the depth of responsibility regarding hazard mitigation and develop a plan to respond for one year, or more. Benefits: Maintain momentum of the recovery period by issuing building permits to repair and reconstruct buildings in a timely fashion while ensuring resilient rebuilding. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-16 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.3.3 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, dam incidents, drought, earthquake, flooding, landslides, subsidence, tsunami, wildfire, hazmat Survey the applicable department and agencies as to their perceived disaster preparedness and mitigation needs. Convene special meetings to prioritize these needs and develop funding strategies. OES-Lead; CAL - County Fire, Sheriff's Dept, and partner agencies Little to no cost Staff Time/Dept. Budget Medium Annual In progress OES convenes regular meetings of the Disaster Planning Advisory Committee. C.3.4 Multi: coastal storm, coastal erosion, dam incidents, drought, earthquake, flooding, landslides, tsunami, wildfire, hazmat Encourage participation of AFN and medically fragile individuals in the County Evacuation Assistance list. OES - Lead; All Support Little to no cost Staff Time/Dept. Budget High Annual Annual implementation; County OES encourages participation of AFN and medically fragile individuals in the County Evacuation Assistance List. County OES continually updates the list ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-17 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.3.5 Tsunami Maintain emergency responder pre-response plans for tsunami inundation areas. OES Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; Tsunami inundation maps have been updated for the pre-plans and will be re-printed in 2019. Tsunami Emergency Response Plan was revised in April 2016 and will be revised again in 2020. C.3.6 Tsunami Install tsunami area warning signs. OES – Lead; Public Works - Support $40,000 to $80,000 Federal Grant and/or General Fund Low Ongoing In progress; The tsunami signs have been obtained from the state. Encroachment Permit Applications for the signs have been submitted to CalTrans. The sign installation should be completed in 2020. The County will apply to be recognized as Tsunami Ready from the National Weather Service in 2021. C.3.7 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, dam incidents, drought, Increase involvement of special needs populations (AFN, disabled, elderly) in education and disaster preparedness activities. Public Health Dept. & OES Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-18 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes earthquake, flooding, landslides, , tsunami, wildfire, hazmat C.3.8 Wildfire; Dam incidents; Flood; Debris Flow Evacuation Planning. Develop enhanced evacuation plans for San Luis Obispo County. Benefits: Reduced evacuation time and potential loss of life County Fire; County Sheriff; County OES $20,000 to $75,000 General Funds; Federal Grant Funding Medium July 2020- June 2021 New C.3.9* Flood Consider joining CRS to promote affordable flood insurance. This action would look at the cost/benefit of joining the CRS, compared to the number of flood prone properties and insurance policies. Being in the CRS includes going above and beyond the meeting minimum NFIP standards, but is not limited to public notification, community education classes, and other measures to raise awareness of flood hazards and promote flood safety. Actions would need to be documented to allow FEMA/ISO to determine the appropriate class rating. Benefits: Reduction in flood insurance rates Public Works, Planning & Building Less than $10,000 Staff Time/ Dept. Budget Medium 2 years New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-19 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes for the general public of the unincorporated area, greater understanding of flood hazards by residents, better property protection. C.3.10 Drought Develop an umbrella water shortage contingency plan to cover rural communities pursuant to AB 1668 and SB 909 for small water suppliers with less than 15 service connections - guidance is anticipated January 2020. Identify communities vulnerable to drought and water shortages and assess reliability of supply; include drought response actions based on lessons learned in the recent droughts; provide information to property and well owners regarding vulnerability of water supplies when issuing build permits, engaging on preparedness actions, etc.; form executive level drought task force to provide regular updates to the County Website or Board of Supervisors; reference County HMP for related drought mitigation actions. * Public Works Less than $10,000 Grants; Staff Time/Dept. Budget Medium 2 years New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-20 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.4.1* Flood Maintain compliance with the National Flood Insurance Program (NFIP) requirements. Planning & Building Dept. Little to no cost Staff Time/Dept. Budget High Ongoing In progress C.4.2* Flood Enhance the ability of community assets, particularly critical facilities, located in the 100-year floodplain to withstand flood impacts. Planning & Building Dept. Little to no cost Staff Time/Dept. Budget High Ongoing In progress; Revised in 2019 from previous description; formerly 'Through Development Review process, restrict construction of essential service facilities in the 100-year flood plain. C.4.3* Wildfire Prevent wildfires through aggressive code enforcement efforts by working with Engine Company Captains and Fire Prevention staff to increase the education and enforcement of PRC 4291, defensible space rules. County Fire Little to no cost Staff Time/Dept. Budget High Ongoing In progress; Defensible space inspections in SRA areas have increased annually exceeding 8,500 in 2018. C.4.4* Wildfire In order to assist fire prevention efforts and to better manage large fires when they occur, continue to improve GIS mapping and tracking efforts by gathering and maintaining relevant GIS data layers and imagery and utilizing the best available mapping applications and software. County Fire Little to no cost Staff Time/Dept. Budget High Ongoing In progress; Continued to develop new map products and produce a variety of pre-attack map products to aid Incident Commanders. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-21 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.4.5 Wildfire Create and maintain fuel breaks in strategic locations. County Fire Less than $10,000 HMA Grants/Staff Time/Dept. Budget High Ongoing In progress; Significant progress has been made and continues in several areas including Cambria, Nipomo, Parkhill, Huasna and Lake Nacimiento. New equipment has been acquired to help specifically with fuel break maintenance C.4.6 Wildfire Utilizing grant funding, develop a Community Wildfire Protection Plan for the County that will: Assess the fire hazard in the County; Prioritize treatment areas; Enhance collaboration among all fire agencies and stakeholders; Streamline environmental review process County Fire Less than $10,000 Grant/Staff Time/Dept. Budget High Ongoing In progress; FSCSLO acquired a FY 2015/16 grant from CAL FIRE for this purpose. Collaborating with all other fire jurisdictions in the County, contractor has produced a draft CWPP which is nearing completion. C.4.7 Earthquake Develop seismic retrofit, or replacement, of the existing South Bay Boulevard Bridge over Los Osos Creek. Seek funding for implementation. Public Works Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; Project funded through project design and environmental phase. Estimated construction 2022/2023. C.4.8 Earthquake Develop seismic retrofit of the existing Lopez Drive Bridge over Arroyo Grande Creek and seek funding for implementation. Public Works Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; Project funded through project design and environmental phase. Estimated construction 2022/2023. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-22 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes C.5.1 Biological Agents/Pande mic Continue communication and coordination efforts amongst Public Health, local hospitals, healthcare workers and first responders to provide information about the effects and transmission of diseases causing epidemics along with specific preventative measures. Public Health Dept. Little to no cost Staff Time/Dept. Budget High Annual Annual implementation; Public Health facilitates the SLO County Disaster Healthcare Coalition to ensure regular communication and coordination among medical and health partners (including hospitals, healthcare workers and first responders) to prepare for, respond to, and recover from public health emergencies, including infectious diseases. www.slopublichealt h.org/Coalition C.5.2 Biological Agents/Pande mic Continue general public and patient education regarding basic hygiene, cough etiquette and other disease prevention methods. Public Health Dept. Little to no cost Staff Time/Dept. Budget Medium Annual Annual implementation C.5.3 Biological Agents and Ag Pests and Disease Support establishment of a Vector Control District in San Luis Obispo County. Agriculture, Public Health Dept. Little to no cost Public Health Dept. Low Deferred Deferred C.6.1 Ag Pests and Disease Continue Agricultural Commissioner’s pest detection, exclusion and eradication efforts. County Agriculture Dept. Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; The Department maintains an extensive program designed to either intercept (exclude) invasive pests prior to establishment ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-23 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes or detect invasive pests early enough that eradication is a feasible option. The targeted pests may vary over time due to changes in pest distribution, additional scientific information regarding destructiveness or invasiveness, or shifts in pest level prioritization. C.6.2 Ag Pests and Disease Continue general public education regarding existing and potential threats from various pests, the necessity for pest exclusion, and the role the public and applicable businesses have in excluding unwanted pests from the County. County Agriculture Dept. Little to no cost Staff Time/Dept. Budget Medium Annual Annual implementation; The Department conducts periodic outreach on various high priority insect pests and diseases, such as the Asian Citrus Psyllid, Sudden Oak Death disease, and the invasive shot-hole borer. These outreach efforts are geared toward both growers and the general public and are designed to alter behaviors that may lead to higher risks of infestation, such as the improper transport of plant material, movement of farm and harvest equipment from infested areas, and the ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-24 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes importation of firewood from infested areas. C.6.3 Ag Pests and Disease Implement eradication and/or control strategies appropriate to the pest species when a pest infestation is detected. Continue to improve rapid response efforts and long-term follow up. County Agriculture Dept. Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; If certain invasive pests are detected within the county, eradication efforts and control strategies are implemented in an effort to control the pest before it can become widely established locally. In the past few years, eradication efforts focused on Asian Citrus Psyllid have been successful as many detections have been made but due to State and County eradication efforts the pest is still not established within SLO County. C.7.1 Adverse Weather: Extreme Heat Establish countywide policy relating to cooling centers to be used during adverse weather events involving heat waves. Extreme heat may also result in high ozone levels which would impact sensitive receptors. Cooling centers should be designed to accommodate air OES & Public Health Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; OES is working with stakeholders to develop a policy and address cooling centers in the Adverse Weather Plan. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-25 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes quality sensitive receptors if necessary. C.7.2 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, drought, flooding, wildfire, Support efforts to reduce greenhouse gas emissions. Public Works Little to no cost Staff Time/Dept. Budget High Ongoing In progress. Refer to Section 6 Capability Assessment for information on the County’s climate change capabilities. C.7.3* Multi: adverse weather, coastal storm, coastal erosion, sea level rise, drought, flooding, wildfire Consider potential climate change impacts when planning new facilities and critical infrastructure. Public Works & Planning & Building Dept. Little to no cost Staff Time/Dept. Budget Medium Ongoing In progress; Refer to Section 6 Capability Assessment for information on the County’s climate change capabilities. C.7.4 Multi: adverse weather, coastal storm, coastal erosion, sea level rise, drought, Continue to promote energy efficiency and renewable energy within the County to reduce peak load demand. Public Works & Planning & Building Dept. Little to no cost Staff Time/Dept. Budget High Ongoing In progress. Refer to Section 6 Capability Assessment for information on the County’s climate change capabilities. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-26 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Cost Estimate Potential Funding Priority Timeline Status/Implementation Notes flooding, wildfire *Mitigates losses to future development The following table provides a summary of the individual mitigation actions by jurisdiction specific to the municipalities and special districts that participated in the 2019 plan update. Together with the County actions the tables provide an overview of all the mitigation actions proposed. More details can be found in the respective jurisdictional annexes. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-27 Table 7-3 Jurisdictional Mitigation Actions Summary ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status City of Arroyo Grande Mitigation Actions AG.1 Flood Residential-Commercial-Government Flood smart projects Residential: relocate, revise, building codes, and provide mitigation assistance Recreation Maintenance Services, Community Development, Emergency Preparedness High Annual Implementation AG.2 Flood Residential-Commercial-Government Flood smart projects Commercial: relocate, revise, building codes, and provide mitigation assistance Recreation Maintenance Services, Community Development, Emergency Preparedness High Annual Implementation AG.3* Flood Conduct a cost to benefit analysis to consider expanding the capacity of the retention basins at various locations in the City of Arroyo Grande Recreation Maintenance Services, Community Development, Emergency Preparedness High Deferred; Limited availability of land to expand basins has resulted in deferral. Future analysis will focus on increasing depth of existing basins. Staff and fiscal constraints are ongoing. AG.4* Flood Creation of Bio-Swales for water conservation Recreation Maintenance Services, Community Development, Emergency Preparedness High Annual Implementation AG.5 Flood Determine cost effective mitigation strategies for Newsom Springs area Recreation Maintenance Services, Community High Deferred; Limited CIP funding has been allocated to this project. In a catastrophic flood event, this area will be negatively ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-28 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Development, Emergency Preparedness impacted. Staff and fiscal constraints are ongoing. AG.6 Flood Conduct a cost to benefit analysis of a flood water diversion system for the City of Arroyo Grande's critical infrastructure and the flood vulnerable Commercial District Recreation Maintenance Services, Community Development, Emergency Preparedness, High Deferred; Limited availability of staff and fiscal resources. AG.7 Earthquake Identify and catalog seismically vulnerable structures Emergency Preparedness High Deferred; URM Buildings in the Village area should have been completely retrofitted. Unknown cataloging of potentially other structures throughout the city. Staff and fiscal constraints ongoing. AG.8* Earthquake Notify public of location of earthquake faults Emergency Preparedness High In progress; Link County of SLO OES Earthquake Plan to Fire Department & City websites. AG.9 Earthquake Notify public of location of Seismic vulnerable structures Emergency Preparedness High In progress; Will be released upon completion of cataloging. AG.10* Fire Encourage the 100' Defensible Space around structures in the Wildland Urban Interface Fire Department, Community Development High In progress; Adoption of Countywide Community Wildfire Protection Plan (CWPP). Pursue grant funding to complete city-specific CWPP Limited availability of staff and fiscal resources. AG.11 Fire Continue weed abatement program Fire Department, Community Development High Annual implementation AG.12* Fire Enforce building codes and ordinances that eliminate the use of wood shake roofs Fire Department, High Annual implementation ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-29 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Community Development AG.13* Fire Enforce codes and ordinances that require fire sprinkler fire systems in all new structures constructed. Fire Department, Community Development High Annual implementation AG.14 Dam Failure Create a community specific Evacuation Plan, including public outreach and education and identify public warning mechanisms and strategies. Emergency Preparedness /Arroyo Grande Police Department High In progress; Existing county-wide plans with evacuation components. County Fire Chiefs have identified community- specific evacuation plans as a strategic priority. AG.15 Dam Failure Exercise Evacuation Plan for effectiveness, including public warning elements. Emergency Preparedness/Arroyo Grande Police Department High Deferred; Will be considered upon community-specific evacuation plans. AG.16 Dam Failure Revise Evacuation plan as appropriate Emergency Preparedness/Arroyo Grande Police Department High Deferred; Will be considered upon community-specific evacuation plans. AG.17 Drought Mitigate Drought Risk Through Water Availability Insurance. Continue to monitor well levels to prevent seawater intrusion while pursuing opportunities for regional recycled water projects that will result in groundwater injection. Public Works; Community Development Department Medium New Benefits: Avoiding seawater intrusion; ensuring adequate water supply of the 5-cities region City of Atascadero Mitigation Actions AT.1 Dam Failure Prepare an inundation map and emergency action plan for a dam failure at Atascadero Lake. Benefits: Reduce or eliminate damages and impacts to 100+ homes and city infrastructure due to potential failure City of Atascadero Public Works Medium/ Low New AT.2 Dam Failure Minimize development along the Salinas River. Maintain setback and open space ordinances along the River and continue the enforcement of existing land use ordinances Community Development Medium Annual Implementation ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-30 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status / Public Works AT.3 Wildfire Wildfire Evacuation Routes. Seek options to improve city road systems to become compliant with Public Resource Code 4290, designed to improve emergency access and egress and emergency evacuation times. Benefits: Improved road widths and clearance; enhanced residence evacuation times in high fire severity zones; elimination or reductions in loss of life Atascadero Fire & Emergency Services High New AT.4 Wildfire Continue to educate public on wildland fire safety Fire Dept. High In Progress AT.5 Wildfire Continue the enforcement on the Weed Abatement Ordinance Fire Dept. High In Progress AT.6 Wildfire Maintain and revise the CWPP Fire Dept. High In Progress AT.7 Wildfire Research emerging fuels management programs and implement where appropriate Fire Dept. High In Progress AT.8 Wildfire Continue fuel load reductions program by annual control burns in the WUI impacting the city Fire Dept. High In Progress AT.9 Adverse Weather – Wind Debris Management Plan Development. Develop a debris management plan to handle slash and leaf accumulation produced by a wind or storm event. Benefits: Reduced impacts due to debris accumulation Public Works; Fire and Emergency Services High New AT.10 Adverse Weather - Wind Plan Around Forced Blackouts. Pacific Gas and Electric is implementing a forced power blackout during anticipated or actual wind events which may impact citizens at risk and residential care facilities; identify target hazards and at-risk populations in the event of a forced blackout. Benefits: Reduced impacts to at-risk populations from rolling blackouts Public Works; Fire and Emergency Services High New AT.11 Earthquake Continue to enforce Uniform Building Code (UBC) provisions pertaining to grading and construction relative to seismic hazards. Community Development / Public Works High In Progress ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-31 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status AT.12 Earthquake Continue to implement an Unreinforced Masonry (URM) building program that determines the structural safety of City owned critical facilities, and retrofit as necessary Community Development / Public Works High In Progress AT.13* Expansive Soils Continue to require a Soils Report for all new building permits Community Development Medium In Progress. Required for all buildings over 1000 square feet AT.14* Flood During the plan check process utilize GIS to ensure the building project meets current Flood Damage Prevention Regulations prior to the issuance of building permits Community Development / Public Works High In Progress AT.15 Landslide Require construction and maintenance of natural and/or human-made retaining structures that will help control subsidence risk in key residential and/or commercial areas Community Development / Public Works Medium In Progress AT.16 Landslide Retrofit or implement stabilizing measures for Atascadero hillside developments that predate current best practices and codes Community Development / Public Works Medium In Progress AT.17 Landslide Located and identify unstable soils through the use of GIS and soil maps Community Development / Public Works Medium In Progress AT.18* Landslide Focus on proposed new developments to determine if soils stabilization is economically feasible. If the soils stabilization is not economically feasible deny, the proposed development or rezone Community Development / Public Works Medium In Progress AT.19 Drought and Water Shortage Implement the water demand management strategies outlined in the Atascadero Mutual Water Company Urban Water Management Plan Community Development / Public Works/ Atascadero Mutual Water Company Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-32 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status City of Grover Beach Mitigation Actions GB.1 Adverse Weather: Wind, Rain, Heat Reduce the negative impact on the community due to weather-related incidents that could include heavy rain, high winds and extreme heat. Benefits: Improved water runoff in low-lying areas, reduced pooling and low impact street flooding; tree trimming, and removal of old trees will reduce falling limbs and trees Public Works Department Low New GB.2 Agricultural Pest Infestation and Disease Help reduce the negative impact on the agricultural community due to pest infestation and disease. Benefits: Through community development and planning, work with existing agricultural property owners to develop safeguards to protect against pest infestation and disease Community Development Department Medium New GB.3* Coastal Storm, Erosion and Sea Level Rise Work in partnership with the State of California and County of San Luis Obispo to identify community impacts associated with coastal erosion through sea level rise and storms. In coordination with the State and County, map areas of the City that may be affected by sea level rise. Benefits: Lessen the impacts on the community from the effects of sea level rise and coastal erosion Public Works Department; Community Development; Emergency Preparedness Medium New GB.4* Dam Failure In collaboration with state, county and other local governments, reduce the negative impact on the community as a result of a dam incident or failure through proper planning and infrastructure maintenance and improvement. City Staff will map areas of potential inundation via its Geographic Informational System and continue to implement the San Luis Obispo County Office of Emergency Services (OES) Emergency Plan. Benefits: Lessen the potential for dam failure and reduce the likelihood of this hazard occurring Public Works Department; Community Development; Emergency Preparedness Medium New GB.5* Drought In collaboration with state, county and other local governments, reduce the negative impact of drought on the community through proper planning and infrastructure maintenance and improvement; continue to monitor well levels to prevent seawater intrusion while pursuing opportunities for regional recycled water projects that will result in groundwater injection; implement water efficient landscaping. Benefits: Avoid sea water intrusion; lessen potential negative impacts on the community as a result of drought or water shortage Public Works; Community Development Department Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-33 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status GB.6 Earthquake Identify and catalog seismically vulnerable structures Emergency Preparedness High Deferred. Limited URM structures. Limited staff and fiscal resources GB.7* Earthquake Implement policies, procedures and regulations which reduce the exposure to earthquake hazards Emergency Preparedness High Annual Implementation. Building and Fire Codes GB.8 Earthquake Protect the improved property and infrastructure vulnerable to earthquake hazards Emergency Preparedness High Annual Implementation. Building and Fire Codes GB.9 Fire Encourage the 100' Defensible Space around structures in the Wildland Urban Interface Fire Department Medium Annual Implementation GB.10 Fire Continue weed abatement program Fire Department Medium Annual Implementation GB.11* Fire Enforce building codes and ordinances that eliminate the use of wood shake roofs Fire Department Medium Annual Implementation GB.12* Fire Enforce codes and ordinances that require fire sprinkler systems in all new structures constructed Fire Department Medium Annual Implementation GB.13* Fire Create a Fire-Smart Community by developing a comprehensive approach to reducing damage and loss due to fires; encourage the 100' defensible space around structures in the Wildland-Urban Interface (WUI); continue weed abatement program to reduce the threat of fire around open spaces; enforce building codes and ordinances that eliminate the use of wood shake roofs; enforce codes and ordinances that require fire sprinkler systems consistent with the California Building Code Fire Department; Community Development; Emergency Preparedness Medium New GB.14* Flood Implement policies procedures and regulations which reduce the exposure to flood hazards; protect the improved property, natural resources and life vulnerable to flood hazards; reduce the vulnerability of community assets, particularly research and identify flooding vulnerability within the city by identifying flood vulnerability within the city by identifying parcels with flood zones; identify funding needs and funding sources; apply for pre-disaster mitigation grants and commence mitigation projects; conclude mitigation projects; evaluate effectiveness of mitigation actions and critical facilities located in the 100-year floodplain Public Works; Parks and Recreation; Community Development; Emergency Preparedness Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-34 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status GB.15* Flood Implement policies, procedures and regulations which reduce the exposure to flood hazards Recreation and Maintenance Services, Public Works and Emergency Preparedness High Annual Implementation GB.16 Flood Protect the improved property and infrastructure vulnerable to flood hazards Recreation and Maintenance Services, Public Works and Emergency Preparedness High Annual Implementation GB.17 Flood Reduce the vulnerability of community assets, particularly critical facilities, located in the 100-year floodplain Recreation and Maintenance Services, Public Works and Emergency Preparedness High Annual Implementation GB.18 Hazardous Materials Require businesses that use, store or transport hazardous materials to ensure that adequate measures are taken to protect public health and safety; coordinate with allied agencies to prepare for hazmat incidents; support training and exercises in response to hazmat incidents; coordinate responses and investigations with the county hazmat team and Five Cities Fire; add gas pipeline mapping to the City's GIS resources; continue to monitor the manufacture, storage, transport of hazardous materials by working with environmental health and public safety agencies to identify effective mitigation actions or requirements that will help reduce the risk of incidents, including the spread of released materials; coordinate with the rail line industries to prepare for train-related hazmat incidents Fire Department; Community Development; Emergency Preparedness Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-35 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status GB.19 Tsunami Develop a comprehensive action plan to reduce damage from a tsunami; display standardized and easy to read signs alerting community members of tsunami hazard zones, evacuation routes and evacuation sites; review tsunami inundation areas and educational needs; review emergency policies and training needs; review tsunami maps and evacuation plans Public Works; Community Development; Emergency Services Medium New GB.20 Tsunami Review Tsunami inundation areas and educational needs Police Department Medium In progress. Countywide Tsunami Plan, and identification of local resource needs. Staff and fiscal constraints GB.21 Tsunami Review emergency policies and training needs Police Department Medium Annual Implementation GB.22 Tsunami Review Tsunami plans, maps, and evacuation plans Police Department Medium In progress. Countywide Tsunami Plan, and identification of local resource needs. County Fire Chiefs identified city-specific evacuation plans as a strategic priority. Staff and fiscal constraints GB.23 Dam Failure Work with our regional partners to reduce the negative impact on the community as a result of a dam incident or failure through proper planning and infrastructure maintenance and improvement. Public Works Department, Community Development Department, Emergency Preparedness Medium New GB.24 Dam Failure Develop a public outreach program to educate residents and businesses in the dam failure inundation areas on their responsibilities and emergency preparedness. Public Works Department, Community Development Department, Emergency Preparedness Medium New GB.25 Dam Failure Develop a dam failure emergency response plan. Public Works Department, Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-36 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Community Development Department, Emergency Preparedness GB.26 Dam Failure Develop a hazard alert system to allow the city and regional partners to contact and alert our residents and businesses about the possibility or a dam failure and flooding caused by a dam failure. Public Works Department, Community Development Department, Emergency Preparedness Low-Medium New City of Morro Bay Mitigation Actions MB.1 Adverse Weather, Coastal Erosion/ Sea Level Rise, Earthquake, Flood, Landslides, Tsunami, Wildfire Educate the planning staff, City administrative staff and elected officials on the importance of keeping up to date on trends and developments in disaster preparedness. Attendance at seminars and lectures on the specific hazards would enable staff to make appropriate recommendations to the governing bodies as they go about the process of approving new developments. All Medium Annual Implementation MB.2 Adverse Weather, Coastal Erosion/ Sea Level Rise, Earthquake, Flood, Landslides, Tsunami, Wildfire Through newsletters, advertisements, speaking engagements and other public contacts, educate the general public and key stakeholders on the issues, responsibilities, and current efforts and successes in the area of hazard mitigation and disaster preparedness All Medium Annual Implementation ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-37 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status MB.3 Adverse Weather, Earthquake, Flood, Landslides, Tsunami, Wildfire Train the police, harbor and fire department supervisors and officers on the activation of the County's early warning system and additional public notification systems to ensure that warning systems function as tools to mitigate potential hazard impacts to citizens. Fire Department/ Police Department / Harbor Department Medium Annual Implementation MB.4 Adverse Weather, Coastal Erosion/ Sea Level Rise, Earthquake, Flood, Landslides, Tsunami, Wildfire Survey the applicable department heads as to their perceived hazard mitigation and disaster preparedness needs. Convene a special meeting of the Disaster Council to prioritize these needs and develop funding strategies Fire Department High Annual Implementation MB.5 Biological agents Participate in the public education process of human and agricultural health related issues as available Admin/FD Medium In progress MB.6 Biological agents Encourage broad participation in County public and agricultural health associated emergency preparedness exercises Admin/FD Medium In progress MB.7 Biological agents Increase involvement of special needs populations (disabled, elderly) in education, awareness, hazard mitigation and disaster preparedness activities Admin/FD Medium In progress MB.8 Earthquake Perform a seismic safety review of all current City structures, infrastructure and facilities paying close attention to proofing structural and non-structural mitigation of all facilities. Convene the Disaster Council to prioritize the findings of the seismic safety review and research funding strategies PS / Fire Department High Annual Implementation MB.9 Flood Continue to work cooperatively with the state and federal flood-related agencies All Medium Annual Implementation MB.10 Tsunami Review the current City Tsunami Plan and update it as necessary to ensure regional consistency with the SLO County Tsunami Plan Admin / Fire Department Medium Annual Implementation ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-38 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status MB.11 Tsunami Educate the public about tsunami dangers and appropriate response and mitigation actions Fire Department Medium Annual Implementation MB.12 Tsunami Evaluate the potential to maximize life safey associated with the use of route signs, tactical staging areas, tsunami safe zones, and traffic control points as outlined in the County Tsunami Plan Fire Department/ PS High Current City Management is re-evaluating the regional plan to implement MB.13 Wildfire, Hazardous Trees Work with the California State Parks and San Luis Obispo County Fire Safe Council to initiate fuel thinning and chipping projects in the Black Mountain area within the City limits Fire Department Medium Annual implementation. State Parks has been a great partner providing great work to improve Black Hill MB.14 Wildfire Continue to support the City's weed abatement program to provide additional wildfire mitigation through vegetation management. Fire Department Medium New MB.15 Flood Amend the Municipal Code to require flood risk disclosure and active acknowledgment of expanded flood risk in property purchases/turnovers. Community Development Medium New MB.16* Flood Require new development in the Sea Level Rise Hazard Overlay Zone to evaluate potential impacts to adjacent or nearby properties from all proposed structural flood protection measures to ensure that these measures will not create adverse direct and/or cumulative on-site or off-site impacts. Community Development Medium New MB.17* Flood Continue to adopt and enforce the most up-to-date California Building Standards Code and California Fire Code, with appropriate local amendments. Community Development; Fire Medium New MB.18 Flood Develop timing triggers for actions to address sea level rise impacts for each character area in Morro Bay based on sea level rise adaptation studies, sea level rise modeling, best available science, and the vision for each character area. Community Development Medium New MB.19* Flood During Development Review, determine if any structures meant for human habitation are to be constructed within the 100-year floodplain or in the Sea Level Rise Hazard Overlay Zone. If necessary, evaluate each structure's safety from flood and sea level rise related hazards, and recommend remedial actions. Development Standards/Community Development Medium New City of Paso Robles Mitigation Actions ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-39 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status PR.1* Drought, Flood, Landslide, Wildfire, Subsidence Integrate the hazard analysis and mitigation strategy into the General Plan’s Safety Element. CMO Low Deferred PR.2* Flood, Landslide, Wildfire, Subsidence Create a GIS-based pre-application review for new construction and major remodels in hazard areas, such high wildfire severity zones, moderate landslide susceptibility areas, and dam failure inundation zones. Community Development Department/ Department of Emergency Services Low Deferred PR.3 Flood, Landslide, Wildfire Establish a county evacuation and re-population plan. Make sure this plan works with other municipalities so that people are not receiving conflicting information about where to evacuate to. Benefit: Reduce death and injury; organized and systemic approach to evacuation of area with predesignated locations on where to go Emergency Services Department High New PR.4 Dam Failure Develop a public outreach program that informs property owners located in the dam inundation areas about voluntary flood insurance. Public Works Department Low Deferred PR.5 Drought Develop a drought contingency plan to provide an effective and systematic means of assessing drought conditions, develop mitigation actions and programs to reduce risks in advance of drought, and develop response options that minimize hardships during drought. Public Works Department High Deferred PR.6 Drought Develop measures to achieve a higher level of irrigation efficiency with respect to plant water requirements, through assistance programs to customers. Public Works Department Low Deferred PR.7 Extreme Heat Initiate an extreme heat public awareness and educational campaign to discuss the dangers of extreme heat, steps each individual can personally take during periods of extreme heat and ways to reduce energy consumption during periods of extreme heat. Emergency Services Department Low Deferred PR.8 Flood Acquire, relocate, elevate, and/or floodproof public works critical facilities that are located within the 100-year floodplain. Public Works Department High Deferred PR.9 Flood Reinforce roads from flooding through protection activities, including elevating the road and installing/widening culverts beneath the road or upgrading storm drains. Public Works Department High Deferred ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-40 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status PR.10 Flood Develop a public outreach program that educates property owners about voluntary flood insurance (targeted at areas that historically flood, but are not acknowledged on FEMA flood insurance rate maps) Public Works Department Low Deferred PR.11 Flood Partner with propane companies and regulating agencies to secure tanks located in special flood hazard areas. Emergency Services Department Low Deferred PR.12 Flood Increase participation in the NFIP by entering the Community Rating System program which through enhanced floodplain management activities would allow property owners to receive a discount on their flood insurance. Public Works Department Low Deferred PR.13 Hazardous Materials Continue to monitor the manufacture, storage, and transport of hazardous materials by working with environmental health and public safety agencies to identify effective mitigation actions or requirements that will help reduce the risk of incidents, including the spread of released materials. Emergency Services Department Low Deferred PR.14* Multi: Landslide, Subsidence Establish local zoning regulations that require the stabilization of landslide-prone areas and land subsidence hazard areas before new development can occur, through stability improvement measures such as the inclusion of interceptor drains, in-situ soil piles, drained earth buttresses, and subdrains. Community Development Department Low Completed on an ongoing basis PR.15 Wildfire Create a new vegetation management program that provides vegetation management services to elderly, disabled, or low-income property owners who lack the resources to remove flammable vegetation from around their homes. Emergency Services Department High Deferred PR.16* Wildfire Implement a fuel modification program for new construction by requiring builders and developers to submit their plans, complete with proposed fuel modification zones, to the local fire department for review and approval prior to beginning construction. Community Development Department/ Emergency Services Department High In progress PR.17 Wildfire Ability to fast track cleanup efforts in the Salinas Riverbed with approvals through Fish and Wildlife, or other agencies involved in environmentally sensitive areas Emergency Services Department High New PR.18 Earthquake Implement Digital “Collector” App for damage inspection program (DINS) Information Technology (GIS) Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-41 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status PR.19 Earthquake Implement Applied Technology Council Placards and Evaluation Forms Community Development Department Medium New PR.20 Earthquake Develop an inventory of public and community building that may be particularly vulnerable to earthquake damage, including pre-1940’s homes and with cripple wall foundations Information Technology (GIS) Medium New PR.21 Adverse Weather: Thunderstorm/ Heavy Rain/Hail/Lighting/Dense Fog/Freeze/High Wind Through newsletters, advertisements, speaking engagements and other public contacts, educate the general public and key stakeholders on the issues, responsibilities, and current efforts and successes in the area of hazard mitigation and disaster preparedness related to adverse weather. Community Development Department/ Emergency Services Department Medium New City of Pismo Beach Mitigation Actions PB.1 Flood; Coastal Storm, Sea Level Rise Dam Incidents, Tsunami Rehabilitate Bello Bridge to withstand flooding and tsunami hazards. Public Works High In progress. Working on Bello Street Bridge plans. About to start construction. Reduces impacts for flooding and emergency evacuation routes PB.2 Flood Work with FEMA Region IX to address any floodplain management issues that may have arisen/arise from the countywide Digital Flood Insurance Rate Map (DFIRM), Community Assessment Visits, and/or the Department of Water Resources (DWR). Community Development, Public Works High In progress. Ongoing work with FEMA re FIRM maps PB.3 Tsunami Display standardized and easy to read signs alerting community members of tsunami hazard zones, evacuation routes, and evacuation sites. Public Works, Police, Fire High In progress. Tsunami signage. Public Works has been coordinating with SLO County OES regarding consistent signage with the County. About to get signage manufactured. Not yet installed. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-42 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status PB.4 Dam Failure Develop a public outreach program that informs property owners located in the dam or levee inundation areas about voluntary flood insurance. Fire, Community Development, Public Works High Deferred PB.5 Earthquake Develop an “Earthquake Education Program” for residents which illustrates what steps the individual can take to prepare for an earthquake and mitigate the effects of an earthquake. Coordinate with Community Emergency Response Teams (CERT) where applicable. Community Development High Deferred. Due to Department workload and funding. PB.6 Earthquake Target old pipelines in seismic areas for upgrades and automatic seismic shut-off switches that cut off natural gas to customers Community Development, Public Works High In progress. Portions of gas pipelines being replaced. Switches? PB.7 Hazardous Materials Conduct a public awareness and educational campaign to raise awareness about the presence of hazardous materials throughout the City. Fire, Police High Deferred. Still needed if there is a hazmat impact to City PB.8 Landslide Stabilize landslide-prone areas through stability improvement measures, including interceptor drains, in situ soil piles, drained earth buttresses, and subdrains. Community Development, Public Works High Deferred. Additional study needed before requiring. PB.9 Wildfire Create a vegetation management program that provides vegetation management services to elderly, disabled, or low-income property owners who lack the resources to remove flammable vegetation from around their homes. Fire High Deferred. Need additional Calfire approval for such a program. PB.10 Wildfire Implement a fuel modification program, which also includes residential maintenance requirements and enforcement, plan submittal and approval process, guidelines for planting, and a listing of undesirable plant species. Require builders and developers to submit their plans, complete with proposed fuel modification zones, to the local fire department for review and approval prior to beginning construction. Fire High In progress. Vegetation reduction and weed abatement programs for fire fuel reduction have been ongoing PB.11 Wildfire Develop and provide funding and/or incentives for defensible space measures (e.g., free chipping day, free collection day for tree limbs). Fire High Deferred. Could be useful but still needs implementation. PB.12 Wildfire Provide assistance to private property owners for brush and weed abatement All cities, county, CalFire High New PB.13 Wildfire Implement a fuel modification program, which also includes residential maintenance requirements and enforcement, plan Fire High In progress. Vegetation reduction and weed abatement ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-43 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status submittal and approval process, guidelines for planting, and a listing of undesirable plant species. Require builders and developers to submit their plans, complete with proposed fuel modification zones, to the local fire department for review and approval prior to beginning construction. programs for fire fuel reduction have been ongoing PB.14 Drought Develop additional water efficient landscape measures for new construction, including the encouragement xerophytic landscape designs. Community Development Department Low New PB.15 Drought Continue to monitor reservoir and well water levels. Develop and enact a tiered water restriction program in the event of drought conditions or other water availability emergency, including possible limits on new construction. Community Development Department High New PB.16 Coastal Erosion Revise the City’s Local Coastal Plan, which includes the General Plan and Zoning Ordinance, to identify all high hazard coastal and bluff erosion areas, identify impacts based on sea-level rise due to climate change, and identify and/or consider additional mitigations measures related to sea level rise, including, but not limited to, variable development setbacks and buffer zones, beach replenishment programs, and bluff revetment and drainage projects. The LCP Update shall include appropriate references to this Hazard Mitigation Plan. Community Development Department Medium New City of San Luis Obispo Mitigation Actions SL.1* Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Regularly review and continue to maintain consistency between the Safety Element, Municipal Code, zoning regulations, hazard area maps, and LHMP implementation strategies. Added 10/2016: Review the implementation and impacts of SB1069 Land use zoning Community Development /Public Works /Fire Medium In progress. Safety Element to be updated in 2021 SL.2 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Train all City employees including fire fighters, police officers, building inspectors, and public works and utilities staff to levels appropriate for their hazard mitigation tasks and responsibilities. Fire Medium In progress. Currently updating a City-wide training matrix to ensure employees have the valid training based on their position. Once the matrix is complete the ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-44 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Hazardous Materials City will hold training to ensure all City employees receive appropriate training and certifications. Utilize new Human Capital Management software to ensure new employees receive training during onboarding. SL.3 Adverse Weather, Earthquake, Flood, Wildfire, Hazardous Materials Provide training for City staff who apply its building regulations and planning standards, emphasizing the lessons learned in locations that have experienced disasters Fire / Community Development /Public Works Medium In progress. Additional modeling has been completed. The results of this modeling indicated that a more expansive model should be created which is underway. SL.4 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Conduct disaster-preparedness exercises for the types of hazards discussed in this LHMP. Fire Medium In progress. Latest Public Point of Distribution drill held at the City of San Luis Obispo was on 10/18/2017. October 2018 Distribution took place on 10/21/18 in Arroyo Grande and Atascadero (the two locations exercised were intended to cover the whole county, including SLO). City plans to continue participating in exercises as allowed. SL.5 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Establish ongoing Disaster Service Worker training program to include training for City staff to deal with emergencies as well as contribute to risk reduction measures. Fire Medium In progress ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-45 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status SL.6 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Review funding opportunities and establish centralized internal procedures to coordinate efforts for securing funds that support risk reduction measures. Admin. - Finance High In progress. Spring of 2019. The City released an RFP to hire a grant writing firm to seek funding opportunities to leverage community improvement. This includes risk reduction measures. SL.7 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Identify hazard mitigation projects eligible for grants as part of the Capital Improvement Program planning process. Public Works/ Utilities Medium In progress. The Mid-Higuera Bypass project is currently being designed. Once design is complete, grant application work will begin. Utilities (new) - A $2 million grant application has been submitted with CalOES for flood proofing mission critical facilities related the Water Resource Recovery Facility. SL.8 Adverse Weather, Earthquake, Flood, Hazardous Materials Assess structural capacity of key assets (including bridges) and pursue infrastructure improvements as necessary. Public Works/ Community Development Medium In progress. As part of 2019-21 financial plan process the City has reviewed and prioritized assets maintenance and replacement. This prioritized asset list will be presented to the City Council for funding consideration. SL.9 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Establish a funded program or mechanism to distribute public information regarding risk reduction activities and projects at City- sponsored events. Identify materials available for use at public education workshops. Coordinate messaging with external agencies such as the American Red Cross and Volunteer Organizations Active in Disasters. Fire Medium In progress. Fire Prevention Open House occurred on and 10/14/17 and 10/13/18. Presentations at Cal Poly orientations for students and their parents. Department is developing new disaster preparedness neighborhood presentation program and ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-46 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status employee disaster worker preparedness beginning FY2020. SL.10 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Support the efforts and education of people with access and functional needs to prepare for disasters. Fire Medium In progress SL.11 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Educate the community on individual preparedness and response to deal with emergencies at times when professional responders would be overwhelmed. Fire Medium In progress. See SL.9 comments SL.12 Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Offer seminars and/or resources to assist local / small businesses in planning for continuity of operations and emergency preparedness. Fire Medium In progress. Fire department staff attend the weekly meetings at the Downtown Association and has updated a fire safety checklist for festival vendors in the downtown, provided education to DTA staff. SL.13* Adverse Weather, Biological, Earthquake, Flood, Wildfire, Hazardous Materials Continue to enforce local codes, ordinances, and standards pertaining to safe development and resiliency to natural and human-caused hazards. Community Development /Fire High In progress. As of April of 2019, permits have been issued on all URM structures. All have been finalized/closed out except for four properties, one of which is currently being retrofitted and remodeled (SLO Brew at 736 Higuera). Permits have been issued on two others (1029 and 1035 Chorro) but have not been ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-47 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status finalized/closed out in permitting system. Current status on these is currently being researched. Records indicate the last of the four has completed Level A strengthening, but still has an outstanding permit - permit records and status is currently being researched. SL.14 Earthquake Develop and provide managers of mobile home parks with information on how to improve the seismic performance of mobile homes and awareness of flood risk. Community Development Medium In progress. Still in planning process; will be incorporated into Safety Element) SL.15 Earthquake, Wildfire, Adverse Weather The Secure and Resilient Electricity action would plan for energy independence and security at critical facilities throughout the City. By providing grid independent onsite renewable energy, storage, and energy management systems, and by providing a planning and financing framework for future investments, the City will be able maintain uninterrupted operations during times of electricity or natural gas grid instability. Fire; police; public works; utilities; administration; parks and recreation High New Benefits: A resilient electricity system (solar and storage) at critical facilities ensure ongoing operations during significant disaster events and ensures viability of electric evacuation vehicles, City fleet, and transit vehicles. SL.16 Earthquake Continue to implement the Unreinforced Masonry Hazard Mitigation Plan and strengthen buildings identified in Levels A and B. Community Development / Fire Medium In progress. See SL.13 comments SL.17 Flood Develop and carry out environmentally sensitive flood reduction programs. Administration - Natural Resources Medium In progress. The City continues to assess high priority erosion and sedimentation sites identified in the Waterway Management Plan and provide maintenance or restoration as appropriate; review City owned property and property with drainage easements covering private properties and conduct ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-48 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status vegetation management/removal as needed; and, complete silt removal projects at key drainage locations on a rotating basis. Assess and remove as necessary undesirable trees from creek system with tree/landscape contractors. Natural Resources Program staff manages vegetation trimming or removal to maintain the riparian corridors. The EIR for the Mid-Higuera Bypass project was adopted and the 95% plans are nearing completion. SL.18 Haz Mat Continue requiring businesses that use, store, or transport hazardous materials to ensure that adequate measures are taken to protect public health and safety. Fire High Fire Department CUPA Participating Agency completes 100% of permitted facility inspections annually to assure compliance with the fire code and state regulations. The fire department is subject to audit by the County CUPA and has passed all recent audits. SL.19 Haz Mat Coordinate with allied agencies to prepare for hazardous materials incidents. Reference City EOP and Training and Exercise Plan; Maintain participation in County hazardous materials team Fire Medium In progress. City Emergency Operations Plan is currently set to be updated. City issued RFP to hire consultant to update plan in Spring of 2019 and is expected to have a completed plan with associated training in Winter of 2020. SL.20 Haz Mat Maintain City’s web site and other outlets with information regarding the safe handling and disposal of household chemicals. Fire Medium In progress/ongoing ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-49 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status SL.21 Wildfire Enhance partnerships with CalFire and the local Fire Safe Council for fuel reduction efforts. Fire Medium In progress. As of March of 2019, The City of San Luis Obispo is now a recognized focus group and voting board member on the Fire Safe Council SL.22 Wildfire, Drought Support ongoing urban forest maintenance and tree trimming programs, to include planting drought-resistant trees and plants. Public Works - Urban Forestry / Fire / Parks & Recreation / Natural Resources Medium In progress. Urban Forest Services continues regular maintenance which includes pruning and dead tree removal in City Streets, Parks and other City owned properties. SL.23 Wildfire Continue to conduct current fuel management programs and investigate and apply new and emerging fuel management techniques. Fire/Natural Resources Director/Parks and Recreation High In progress. The Natural Resource Manager has taken lead on all fuel management funds and projects in the City Open Space. Additional grant funding has been obtained to augment allocated fuel management budget. SL.24 Wildfire Require an enhanced fire protection plan in Local Very High Fire Severity Zones. Fire Medium In progress. SL.25 Biological Continue offering free flu vaccines to City employees. Human Resources Medium In progress. Continued participation in the County Public Health Point of Distribution program. SL.26 Biological Educate and encourage City employees to maintain a healthy work environment by utilizing sick and other leave benefits to avoid coming to work when sick or contagious and encouraging employees to develop plans for caring for sick family members taking care of ill family members. Human Resources Medium In progress. Include in ongoing wellness, benefits, and leave of absence training, education, and general communications. Avila Beach Community Service District Mitigation Actions ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-50 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status AB.1 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Flood; Landslide and debris flow; Earthquake Avila Beach Revetment Repairs to ensure Avila Beach Drive doesn't fail due to erosion and undermining or landslide. County of SLO; Port San Luis Harbor District; Avila Beach CSD Medium New. Partner with Port San Luis Harbor District on solution (see Action PS.3 in the Harbor District’s annex). Survey existing jetty; develop repair and augmentation plan; repair revetment. The road is also at risk of landslide. Benefits: Ensures The road is essential for access to Diablo Canyon NPP and Port San Luis. AB.2 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Flood Avila Beach Drainage Station. Come up with a solution for drainage in Avila Beach which accumulates along Beach Colony Lane and the Avila Parking Lot; install pump station or diversion for flood waters; identify funding for long-term operations and maintenance. County of SLO; Port San Luis Harbor District; Avila Beach CSD Avila Beach property owners Medium New. Partner with Port San Luis Harbor District on solution (see Action PS.3 in the Harbor District’s annex). Survey existing jetty; develop repair and augmentation plan; repair revetment. Benefits: Ensures The road is essential for access to Diablo Canyon NPP and Port San Luis. Ground Squirrel Community Service District Mitigation Actions GSH.1 Adverse Weather, Landslides and Debris Flow, Wildfire Improve drainage on “Mud Corner” near 5661 Ground Squirrel Hollow Road to mitigate debris flow on road. GSHCSD, with property owner and County High New A chronic problem during adverse weather due to debris flow from unstable soil on private property. GSHCSD will initiate dialog with property owner. GSH.2 Adverse Weather Chip Seal Overlays to extend the life and strengthen chip seal roads during extreme heat and other adverse weather. This will also help support access from emergency vehicles needed for firefighting GSHCSD, perhaps coop purchasing with County Medium New GSHCSD does not generate sufficient funds. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-51 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status GSH.3 Adverse Weather, Landslides and Debris Flow, Wildfire Implement road edge erosion control to mitigate undermining and failure of the road. GSHCSD High New GSHCSD does some repair with available funding. Repairs are often needed after heavy weather when ruts form along the road edge. This project would reduce the need for periodic repairs. GSH.4 Wildfire (access) Implement “Replacement Financing” to build District funding capabilities for hazard mitigation and help ensure the District can maximize funding available for on-going maintenance of the road system. GSHCSD Medium New GSH.5 Landslides and Debris Flow, Earthquake/Liquefaction, Wildfire Mitigate landslide risk through improvements to the Stagg Hill Road edge cribbing. GSHCSD Medium New There is a short section where the road edge is supported by timber cribbing with limited life remaining. Heavy vehicles and decaying wood could exacerbate the issue. GSH.6 Landslides and Debris Flow, Earthquake/Liquefaction, Wildfire Build an emergency shelter with power generator and water well. GSHCSD High New The District has an opportunity to purchase a parcel now for a dual purpose community shelter and meeting room; will be pursued as available funding allows. Heritage Ranch Community Service District Mitigation Actions HR.1 Adverse Weather Consider support for communication towers and other communication infrastructure to be built within the HRCSD Boundary/property to provide expanded warning capabilities related to adverse weather. Communication companies Low New HR.2 Dam Incidents; Drought; The District currently has a vertical well project identified to mitigate low flows from the Dam during outages and/or drought, as well as to HRCSD High Some preliminary engineering completed (siting, borings, conceptual drawings, etc.) ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-52 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Flooding; Landslide /Debris Flow provide redundancy (mitigate) for high flow releases that have historically damaged or destroyed the current gallery well system. A vertical well(s) would provide mitigation for both low and high flows (drought and Dam incidents). A vertical well(s) would improve raw water quality if debris flow occurs within Nacimiento Reservoir and River like it did after the Chimney Fire. HR.3 Dam Incidents; Drought; Flooding Continue to engage with San Luis Obispo County Flood Control & Water Conservation District, and Monterey County Water Resources Agency to operate the Dam in a manner more conducive to preventing these hazards. HRCSD; SLOCFCWCD; MCWRA Medium New HR.4 Earthquake Increase risk awareness of the potential impacts of earthquakes to water and wastewater systems and conduct outreach to residents of same; Continue to partner with the Heritage Ranch Owners Association and their Emergency Services Committee on emergency planning. HR Owners Association, HRCSD Low New HR.5 Wildfire Continue public education and awareness programs to advise residents of risk to life, health and safety; include information on defensible space and safe evacuation; Continue to partner with the Heritage Ranch Owners Association and their Emergency Services Committee on emergency planning. HR Owners Association, HRCSD Medium New Los Osos Community Service District Mitigation Actions LO.1 Flood Improve drainage, public education on construction management, evacuation routes and vegetation management LOCSD, SLO County High In progress. All drainage areas have been improved/upgraded. Vegetation management is in progress LO.2 Drought, Earthquake Engineer and install a SCADA system to improve water efficiencies and mitigate water loss if system is compromised during an earthquake. LOCSD High This is a 2019/2020 scheduled project LO.3 Wildfire Educate the public to take precautions to prevent potentially harmful fires and be educated about surviving them. The District is encouraging local organizations to involve the residents of Los Osos and is helping coordinate town hall meetings, Community Emergency Response Team training and sending social media blasts regarding fire safety. There are many local organizations that residents can join in Los Osos CSD / South Bay Fire Dept High Annual Implementation ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-53 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status order to be better prepared in case of a fire; Fire Safe Council, Fire Wise Cabrillo, and the Emergency Services Advisory Committee to the Los Osos Board of Directors. Benefits: With an involved community we hope to reduce risks of wildland fires to a minimum. In case of a wildfire, we hope that the community will be prepared in order to avoid human and property loss. Nipomo Community Service District Mitigation Actions N.1 Earthquake Retrofit treatment facility buildings and process infrastructure to withstand earthquake shaking. NCSD Medium Not started/Begin Assessment Process 2020 N.2* Drought Add secondary source of water supply as additional supply to hedge against future drought conditions. NCSD High Planned to be completed by 2025 N.3 Wildfire Install backup generators at key water production facilities to ensure water availability during power grid failures or brownouts and also to ensure that firefighting capacity remains. NCSD High 4 sites to be retrofitted, one per year starting Fiscal Year 2021 Oceano Community Service District Mitigation Actions 1A – 7.2 1.A - Through newsletters, speaking engagements and other public contacts, continue to educate the general public and key stakeholders on the District’s issues, responsibilities, and current efforts and successes in the area of disaster preparedness. 1.B - Utilize the District’s website to inform the public of hazard mitigation efforts, disaster preparedness messages, and emergency situation information. 2.A - Educate the Oceano Advisory Committee (OAC) members and elected OCSD BOD members on the importance of keeping current on trends and developments in disaster preparedness. 2.B - Encourage OAC members to attend local seminars and lectures on naturally occurring hazards so that they may better understand and assist County Planning staff as they process future development. 2.C - In order to better protect life and property, continue to accumulate from the county accurate and comprehensive series of maps and data sets that pertain to the District’s earthquake, tsunami and flood threats. 3.1A - Develop a Continuity of Operations Plan (COOP) for the District and train all essential staff on their roles and responsibilities as delineated in the Plan. 3.1B - Update the existing Emergency Operations Plans and supporting documents to ensure coordination with the County Emergency Operations Center (EOC), Emergency Response Plans and SOP’s. 3.1C - Train all District department managers and key staff members on their roles and responsibilities in emergency management and the District DOC as outlined in independent study courses FEMA/National Incident Management System - ICS 100, 700, and 800. 3.1D - Working with SLO County OES, increase participation by District staff members in disaster drills put on by the County. ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-54 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status 3.1E - Send one District management employee to the California Specialized Training Institute (CSTI) Public Information Officer Course. 3.1F - Support the efforts of the FCFA in the implementation of the Five Year Strategic Plan. 3.2A - In order to ensure that employees are available to assist during a major emergency, have all OCSD departments adopt a Family Support Plan. (Note: A model plan is available through SLO County OES.) 3.2B - Make improvements to wastewater collection systems by replacing or relining collection pipes so as to reduce sewer overflows and limit inflow and infiltration subsequently reducing the public health threat. 3.2C - Train staff on the proper techniques for containing sewer system overflows (SSO Protocols). 3.3A - Work with the South County ARES/RACES group in developing a Communications Master Plan for re-establishing District’s radio communications systems. 3.3B - Utilize the South County ARES/RACES group expertise, obtain and install a base station radio, mobile radios, and a standby power source to facilitate communications throughout the District as outlined in the Communications Master Plan. 3.4A - Develop a plan to provide standby power to the following essential service systems/functions: water well #8, the Administration Building, and the Sheriff’s Substation. 3.4B - Collaborate with the Sheriff’s office on funding sources for a standby power system for the substation and the administration building. 3.4C - Work with PG&E and County OES to explore potential funding sources for an auxiliary power source for water well # 8. 4.1A - Support the efforts of the county in maintaining compliance with the National Flood Insurance Program (NFIP) requirements. 4.1B - Through the Development Review process (OAC), ensure the County restricts construction of essential service facilities in the 100-year flood plain. 4.1C - Continue to work cooperatively with the county, state, and federal flood related agencies for funding improvements through grant and agency programs. 4.1D - Support the County’s efforts to improve the drainage from the Front Street/Hwy. 1 flooding areas through a combination of vegetation management and storm drain improvements along Hwy. 1, moving the water to the Arroyo Grande Creek. 4.1E - Relocate the District’s water and sewer lines that will be impacted by the Front Street/Hwy. 1 storm drain project. 4.1F - Support the efforts of the County and the Flood Control District in upgrading the Arroyo Grande Creek levee on both the north and south sides through a combination of vegetation and sediment management and raising both the north and south sides of the levee in a number of places. 5.1 - Working with SLO County OES, increase the public’s awareness and participation in earthquake preparedness activities such as the annual Great California Shake-Out drill. 5.2A - Continue replacing the water lines that are most vulnerable to an earthquake as delineated in the Cannon study. 5.2B - As delineated in the RRM Facilities Study, develop a replacement schedule for buildings found to be vulnerable to an earthquake. 5.3A - Support the FCFA efforts to train fire department staff in the California State Fire Marshal’s Rescue System 1 and 2 programs. 5.3B - Send one District management employee to the California Specialized Training Institute (CSTI) Introduction to Earthquake Management Course. 6.1A - Educate community members on the impacts associated with disposing of household hazardous materials on the wastewater system and provide advice on proper storage and disposal techniques. 6.1B - Continue efforts to educate applicable employees on the handling, use, storage and disposal of hazardous materials utilized in the workplace. 6.2 - Support the FCFA in training 2 first responders to the Hazardous Materials Technician Level (CSTI) ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-55 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status 7.1 - Continue working with County OES in the distribution of the existing tsunami public education pamphlet/map to the visitors and residents in the Tsunami inundation zone. 7.2 - Work with County OES and the California Coastal Commission to post evacuation route signage along Pier Street, and in the Airport and Oceano Campground areas. San Miguel Community Service District Mitigation Actions SM.1 Wildfire Improve ISO rating. As part of this project the District will sponsor a chipping program and green waste management program to support vegetation management/defensible space on properties within the district. The District will also provide public information to the Community Members on how to prepare homes creating Defensible Space, and Ready Set Go information as well. Cal Fire High Annual implementation SM.2 Wildfire Increase fire department staffing San Miguel Fire Medium Planning stage SM.3 Flood, Earthquake Replace the current wastewater treatment facility to current seismic design standards San Miguel CSD, Monsoon Consultants High Planning stage SM.4 Drought and Water Shortage Provide additional or larger water storage tanks San Miguel CSD Medium Planning stage SM.5 Drought and Water Shortage Replace aging water and wastewater underground piping San Miguel CSD Medium Planning San Simeon Community Service District Mitigation Actions SS.1* Drought, Adverse Weather Reservoir expansion project. Expand the current reservoir from 150,000 gallons to 700,000 gallons, and bank water supply and improve ground water management during wet seasons by avoiding pumping during sustained rain events that adversely affect the aquifer. San Simeon CSD High New Benefits: Improved accessibility and a sustainable potable water supply for existing customers by having a larger, cleaner water supply; improved fire flow/suspension requirements; ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-56 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status sustainable water supply for future developments SS.2 Wildfire Create defensible space around the San Simeon Wastewater Treatment Plant San Simeon CSD Medium New SS.3 Flood, Coastal Storms /Coastal Flood/Sea Level Rise; Earthquake Consider mitigation options and possible relocation of Wastewater Treatment Plan to mitigate against riverine and coastal flooding, sea level rise, and incorporate seismic design. San Simeon CSD Medium New Templeton Community Service District Mitigation Actions T.1 Adverse Weather(thunderstorm, lightning, high wind, extreme heat), Drought and Water Shortage, Earthquake, Flood, Wildfire Determine backup power needs and requirements for various locations within the District determined to be critical to maintain essential District services. Install quick-connects at identified facilities. Research and purchase appropriately sized generators or portable generator(s). Fire High New. Much of TCSD’s critical infrastructure lacks backup power, including water wells and sewer lift stations. This could severely compromise the District’s ability to deliver essential services during a power outage caused by hazards such as adverse weather, earthquake, flood, or wildfire. This becomes even more critical in the case of a drought or water shortage. The potential failure of one or more wells due to declining groundwater levels makes it all the more essential that the other wells have reliable backup power. T.2 Drought/ Water Shortage Initiate a Drought public awareness and educational campaign to discuss the impacts of drought and water shortage, and steps each District Administration Medium New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-57 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status individual can take during periods of drought and ways to reduce water consumption during periods of drought. T.3 Wildfire Continue to support the District's weed abatement program to provide additional wildfire mitigation through vegetation management. Fire Medium New Cayucos Sanitary District Mitigation Actions CAY.1 Adverse Weather, Coastal Storm/ Erosion/Sea Level Rise, Earthquake, Flood, Landslides and Debris Flow, Tsunami, Wildfire Conduct a Critical Facility Audit and Monitoring to determine additional hazard risk and develop appropriate mitigation as applicable. Cayucos Sanitary District Medium New CAY.2 Adverse Weather, Coastal Storm/ Erosion/Sea Level Rise, Earthquake, Flood, Landslides and Debris Flow Implement programmed improvements to pipelines and infrastructure as indicated in the Cayucos Sanitary District Capital Improvement yearly budget with a focus to build resiliency to multiple hazards including adverse weather, earthquakes, landslides, coastal storms, and flooding. Cayucos Sanitary District High New CAY.3 Adverse Weather, Coastal Storm/ Relocation of Cayucos/Morro Bay WWTP to mitigate risk to coastal hazards, tsunami, and flood and enhance seismic resiliency in new facility. Cayucos Sanitary District High New Construction is in progress in 2019. Plant is expected to be operational by end of 2020 ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-58 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Erosion/Sea Level Rise, Earthquake, Flood, Landslides and Debris Flow, Tsunami Port San Luis Obispo Harbor Mitigation Actions PS.1 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Tsunami; Earthquake Future Avila Pier Replacement. Develop replacement plan; remove wooden pier; replace pier with structure able to withstand sea level rise and heavy storms and waves, ideally with stronger materials like concrete and steel. Port San Luis Harbor District Low New Benefits: Ensures continued existence of Avila Pier which serves the public and is a tourist attraction PS.2 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Tsunami Revetment and Jetty Augmentation. Survey existing jetty; develop repair and augmentation plan; repair or replace revetment and jetty. Possibly replace with seawall or install seawall on top of existing jetty. Port San Luis Harbor District High New Benefits: Would allow the continuation of port operations and businesses during storms and sea level rise. Would allow full use of launching facilities and parking which is vital to commercial and recreational fishing. It would help ensure the preservation of buildings and facilities It could possibly decrease the amount of dredging which would benefit the environment. PS.3 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Avila Beach Revetment Repairs to ensure Avila Beach Drive doesn't fail due to erosion and undermining. County of SLO; Port San Luis Harbor District; Avila Beach CSD Medium New Survey existing jetty; develop repair and augmentation plan; repair revetment. Benefits: Ensures The road is essential for ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-59 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Flood; Landslide and debris flow; Earthquake access to Diablo Canyon NPP and Port San Luis. PS.4 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Flood Avila Beach Drainage Station. Come up with a solution for drainage in Avila Beach which accumulates along Beach Colony Lane and the Avila Parking Lot; install pump station or diversion for flood waters; identify funding for long-term operations and maintenance. County of SLO; Port San Luis Harbor District; Avila Beach CSD; Avila Beach property owners Medium New Benefits: Flood prevention in low-lying areas in Avila Beach; reduction of health hazards caused by flooding PS.5 Coastal Storm/ Coastal Erosion/ Sea Level Rise; Tsunami Avila Pier Rehabilitation. Develop replacement plan; repair damaged piles and above water pier structure; open full pier to public. Port San Luis Harbor District Medium New Benefits: Allow re-opening and full access to Avila Pier; currently the pier is in disrepair and is in danger of further damage during storms if repairs are not made PS.6 Earthquake Harbor Patrol and staff to review Harbor District’s Emergency Action Plan and procedures periodically and maintain a hardcopy on-site Port San Luis Harbor District Medium New PS.7 Earthquake Reinforce and maintain revetment below and hillside above Avila Beach Drive to prevent road failures and closures due to earthquake caused landslides County of SLO, Port San Luis Harbor District Medium New PS.8 Wildfires Continue weed abatement and maintaining defensible space on Harbor District properties Port San Luis Harbor District Medium New PS.9 Tsunami Harbor Patrol and staff to review County’s Tsunami Response Plan and procedures periodically and maintain a hardcopy on-site Port San Luis Harbor District High New ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-60 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status PS. 10 Adverse Weather: High Winds, Hail, Frost Use GIS to develop vulnerability assessment model of structures at risk of damage from high winds; replace roofing systems nearing end of expected lifespan with PVC roofing systems to minimize damage and prevent uplift. Reinforce and upkeep Harford Pier Canopy to prevent wind related damage and failure. Port San Luis Harbor District Medium New/Ongoing. Roof replacements with heat-welded PVC flat roofs for two structures on end of Harford Pier. Inspect and reinforce Harford Pier Canopy to maintain wind resilience PS. 11 Adverse Weather: Dense Fog Maintain maritime visual navigation aids: 6 USCG lighted channel markers and Point San Luis Lighthouse; provide boaters, fishermen, and staff with weather forecasts. Use storm lights on Harford Pier during extreme fog. Port San Luis Harbor District Low Keep channel markers maintained and replace as needed. Maintain and upgrade storm lights on Harford Pier. Seek replacement with low setting for fog. PS. 12 Adverse Weather: Lightning Maintain and periodically review Emergency Action Plan and Fire Plans. Maintain lightning rods on Harford Pier. Port San Luis Harbor District Low Maintain lightning rods on Harford Pier. PS. 13 Adverse Weather: Extreme Heat Provide seasonal training to staff on the Heat Illness Prevention Plan (HIPP) and update plan as needed Port San Luis Harbor District Low New. In process of preparing updated draft of District’s HIPP PS. 14 High Winds Assess the historic canopy at the end of the Harford Pier for reinforcement and repair options. Port San Luis Harbor District TBD The canopy was repaired in 2011, and is again in need of reinforcement and/or repair. SLO FCWCD MITIGATION ACTIONS FCWCD.1 Flood Review and revise the policies of the San Luis Obispo County Flood Control and Water Conservation District to help reduce the exposure to flood hazards Flood Control and Water Conservation District Medium In progress FCWCD.2 Flood Identify flood prone areas within communities and define mitigation options under Community Drainage Studies. Engage stakeholders in defining, funding, and implementing community drainage facilities. Flood Control and Water Conservation District High In progress. Drainage facility projects are identified in the community drainage studies. Implementation is in progress. The following projects identified in the studies are under ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-61 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status development: Hwy 1 at 13th Street drainage (Oceano), Salinas Avenue drainage (Templeton), Mallagh Street drainage (Nipomo), Mountain Springs Road sedimentation basin (Paso Robles). Revise to: Continue to develop and update the community drainage studies and prioritize and implement the recommended solutions. FCWCD.3 Flood Continue to update and enhance Emergency Response Plan for Arroyo Grande Creek Levee System. Develop safeguards for levee protection. Implement Arroyo Grande Waterway Management Plan to maximize floodway capacity of the facility. Flood Control and Water Conservation District High In progress. The County’s Dam and Levee Failure Plan, which covers the Arroyo Grande Creek Levee, was updated in February 2015 and February 2016. The Arroyo Grande Creek Levee Failure Emergency Response Plan was updated in March 2016. Revisions include: revised checklists to reflect actual response actions; divided checklists by position; updated figures and maps to reflect current conditions; updated emergency contact information; added Appendix 3: Radio Procedures and Call List; added Appendix 6: Personal Safety Plan. The District has continued to work cooperatively with the State and Federal funding agencies for implementing flood related improvements. The District has been awarded the following grants: ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-62 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status Proposition 1E Stormwater Flood Management Grant ($2.8M, 2013) Proposition 84 IRWM Implementation Grant ($2.2M, 2013) FEMA Hazard Mitigation Grant ($3.0M, 2018) The Oceano Drainage Improvement Project (Hwy 1 at 13th Street) is funded by various state and federal grants. FCWCD.4 Flood Continue to work cooperatively with the state and federal flood related agencies for funding improvements through grant and agency programs Flood Control and Water Conservation District High In progress FCWCD 5. Drought Develop a Regional Water Infrastructure Resiliency Plan to identify key interconnections to construct and agreements to get water from where it is to where it is needed to mitigate water shortages and drought impacts Flood Control and Water Conservation District High New FCWCD 6 Dam Incidents Perform destructive testing of the Lopez Dam to quantify previous investigation data and direct what repairs are needed. Conduct geotechnical investigation on Lopez Terminal Dam. FCWCD, DSOD High The Lopez Dam and Lopez Terminal Dam are considered to be a high hazard dams by the Dept. of Safety of Dams (DSOD) due to the large population downstream. DSOD mandated that all spillways of High Hazard Dams be investigated for structurally integrity and design. Preliminary studies have shown that although the Lopez Dam spillway is in fair condition it needs repairs related to spillway ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-63 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status under drains, crack repair, spalling concrete repair, and various other maintenance items that will insure that the spillway performs well in a spill event. The Lopez Terminal Dam seismic assessment is in process. South San Luis Obispo County Sanitation District Mitigation Actions SD.1 Coastal Flood/ Coastal Erosion/ Sea Level Rise Coastal Monitoring Program. Regularly monitoring flood and other coastal hazards at the site and management responses to those hazards both on and off site. Identifying how those hazards are impacting and affecting operations of the wastewater treatment plant. Identifying changes necessary to allow continued appropriate and required functioning of the plant. Identifying flood/hazard “triggers” to establish when actions (such as retrofits, upgrades, and including plant relocation) need to be pursued in response to specific flood/hazard events or flood management activities. SSLOCSD High New. Benefits would include reduced coastal flooding impacts SD.2 Flood; Coastal Flood/ Coastal Erosion/ Sea Level Rise; Earthquake, Dam incident Redundancy Project - Flood Risk Mitigation Strategy. All critical new and existing facilities will be installed or upgraded to be protected from the 100-year flood event on Arroyo Grande Creek as defined by Flood Insurance Rate Map (FIRM) maps. This would also protect these facilities from floods caused by sea level rise for the design life of the facilities and provide additional protection from dam incident flooding. SSLOCSD High New. Benefits include Protection of critical structures, equipment, continued operations of the wastewater treatment plant during a 100-year flood event. Redundant facilities will also be designed according to current state seismic design standards. SD.3 Earthquake Wastewater Treatment Plant Redundancy Project – Implementation of liquefaction hazard mitigation measures per the 2019 Redundancy Project Geotechnical Report during construction of additional treatment infrastructure. SSLOCSD High New. Benefits: Ability to conceptualize the cost of relocating the plant if necessary, in the future. ($130,000,000 in 2016 dollars to relocate); relocation would incorporate current seismic design and ••• Section 7 Mitigation Strategy San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 7-64 ID Hazard(s) Mitigated Description/Background/Benefits Lead Agency and Partners Priority Action Status provide added dam incident mitigation benefits. ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-1 SECTION 8 IMPLEMENTATION AND MONITORING Implementation and maintenance of the plan is critical to the overall success of hazard mitigation planning. This is Planning Step 10 of the 10-step planning process. This section provides an overview of the overall strategy for plan implementation and maintenance, and outlines the method and schedule for monitoring, updating, and evaluating the plan. The section also discusses incorporating the plan into existing planning mechanisms and how to address continued public involvement. 8.1 Implementation DMA Requirement §201.6(c)(4)(ii): [The plan shall include a] process by which local governments incorporate the requirements of the mitigation plan into other planning mechanisms such as comprehensive or capital improvement plans, when appropriate. Once adopted, the plan faces the truest test of its worth: implementation. While this plan contains many worthwhile actions, the participating jurisdictions will need to decide which action(s) to undertake first. Two factors will help with making that decision: the priority assigned the actions in the planning process and funding availability. Low or no-cost actions most easily demonstrate progress toward successful plan implementation. Implementation will be accomplished by adhering to the schedules identified for each action (see Section 7 for county mitigation actions and the annexes for local mitigation actions), and through constant, pervasive, and energetic efforts to network and highlight the multi-objective, win-win benefits of each project to the San Luis Obispo County community and its stakeholders. These efforts include the routine actions of monitoring agendas, attending meetings, and promoting a safe, sustainable community. Mitigation is most successful when it is incorporated into the day-to-day functions and priorities of government and development. Implementation will be accomplished by adhering to the schedules identified for each action and through constant, pervasive, and energetic efforts to network and highlight the multi-objective, win-win benefits to each program and the San Luis Obispo County community and its stakeholders. This effort is achieved through the routine actions of monitoring agendas, attending meetings, and promoting a safe, sustainable community. Additional mitigation strategies could include consistent and ongoing enforcement of existing policies and vigilant review of programs for coordination and multi-objective opportunities. Simultaneously to these efforts, it is important to maintain a constant monitoring of fund ing opportunities that can be leveraged to implement some of the more costly recommended actions. This will include creating and maintaining a bank of ideas on how to meet local match or participation requirements , should grants be pursued. When funding becomes available, the participating jurisdiction’s will be in a position to capitalize on the opportunity. Funding opportunities to be monitored include special pre - and post-disaster funds, special district budgeted funds, state and federal earmarked funds , and other grant programs, including those that can serve or support multi-objective applications. ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-2 8.1.1 Role of Hazard Mitigation Planning Committee in Implementation and Maintenance With adoption of this plan, the participating jurisdictions will be tasked with plan implementation and maintenance. The participating jurisdictions, led by the County of San Luis Obispo Office of Emergency Services, agree to: • Act as a forum for hazard mitigation issues; • Disseminate hazard mitigation ideas and activities to all participants; • Pursue the implementation of high-priority, low/no-cost recommended actions; • Keep the concept of mitigation in the forefront of community decision making by identifying plan recommendations when other community goals, plans, and activities overlap, influence, or directly affect increased community vulnerability to disasters; • Maintain a vigilant monitoring of multi-objective cost-share opportunities to help the community implement the plan’s recommended actions for which no current funding exists; • Monitor and assist in implementation and update of this plan; • Report on plan progress and recommended changes to the County of San Luis Obispo Board of Supervisors and the governing boards of the other participating jurisdictions; and • Inform and solicit input from the public. The primary duty of the participating jurisdictions is to see the plan successfully carried out and to report to their community governing boards and the public on the status of plan implementation and mitigation opportunities. Other duties include reviewing and promoting mitigation proposals, considering stakeholder concerns about hazard mitigation, passing concerns on to appropriate entities, and posting relevant information on the county website (and others as appropriate). 8.1.2 Process for Incorporation into Existing Planning Mechanisms Another important implementation mechanism that is highly effective and low -cost is incorporation of the hazard mitigation plan recommendations and their underlying principles into other county and city plans and mechanisms. Where possible, plan participants will use existing plans and/or programs to implement hazard mitigation actions. This plan should also be cross-referenced when related planning mechanisms are updated. As previously stated above, mitigation is most successful when it is incorporated into the day-to-day functions and priorities of government and development. As described in this plan’s capability assessment and jurisdictional annexes, the county and participating jurisdictions already implement policies and programs to reduce losses to life and property from hazards. This plan builds upon the momentum developed through previous and related planning efforts and mitigation programs and recommends implementing actions, where possible, through these other program mechanisms. These existing mechanisms include (but not limited to) the following: • County and local general plans • Community service district area plans and master plans • County and local emergency operations plans • County and local ordinances • Flood/stormwater management/master plans • Community wildfire protection plans • Groundwater Sustainability Plans ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-3 • Integrated Regional Water Management Plans • Stormwater Resource Plans • Urban Water Management Plans Capital improvement plans and budgets • Other plans and policies outlined in the capability assessments in the jurisdictional annexes • Other plans, regulations, and practices with a mitigation focus HMPC members involved in the updates to the planning mechanisms will be responsible for integrating the findings and recommendations of this plan with these other plans, programs, etc., as appropriate. As an action step to ensure integration with other planning mechanisms the County Office of Emergency Services Manager and the County Planning & Building Department or designee will discuss this topic at the annual meeting of the HMPC described below in subsection 8.2.1. The HMPC will discuss where there are opportunities to incorporate the plan into other planning mechanisms and who would be responsible for leveraging those opportunities. HMPC members representing local jurisdictions will work with their jurisdictional planning teams to integrate their identified mitigation actions into their own loca l plans and programs. Efforts to integrate the hazard mitigation plan into local plans, programs, and policies will be reported on at the annual HMPC plan review meeting, and a record of successful integration efforts will be kept. Examples of a process for incorporation of the LHMP into existing planning mechanisms include: • As recommended by Assembly Bill (AB) 2140, each community should adopt (by reference or incorporation) this LHMP into the Safety Element of their General Plan(s). Evidence of such ado ption (by formal, certified resolution) shall be provided to Cal OES and FEMA. • This 2019 update occurred in parallel with and slightly ahead of the update of the County’s General Plan Safety Element. This allows for the related goals and policies to be consistent with and cross referenced in the General Plan Safety Element. • Climate change considerations consistent with SB 379, including adaptation strategies, have been incorporated into the HMP update and cross linked with related Safety Element considerations (see summary in Appendix F). • Integration of wildfire actions identified in this mitigation strategy with the actions and implementation priorities established in existing and recently updated Community Wildfire Protection Plan (CWPP). • An umbrella mitigation action was developed in 2019 related to “Implement drought mitigation strategies identified in related planning documents.” This action references Groundwater Sustainability Plans, Integrated Regional Water Management Plans, Stormwater Resource Plans, Urban Water Management Plans, etc. that all have actions that relate to drought mitigation. • Using the risk assessment information to inform the hazard analysis in the San Luis Obispo County Emergency Operations Plan when that plan is updated. Efforts should continuously be made to monitor the progress of mitigation actions implemented through these other planning mechanisms and, where appropriate, their priority actions should be incorporated into updates of this hazard mitigation plan. ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-4 8.2 Maintenance, Monitoring and Evaluation DMA Requirement §201.6(c)(4)(i): [The plan maintenance process shall include a] section describing the method and schedule of monitoring, evaluating, and updating the mitigation plan within a five-year cycle. Plan maintenance implies an ongoing effort to monitor and evaluate plan implementation and to update the plan as progress, roadblocks, or changing circumstances are recognized. 8.2.1 Maintenance/Monitoring Schedule The San Luis Obispo County Office of Emergency Services is responsible for initiating plan reviews and will consult with the heads of participating departments and other participating jurisdictions. In order to monitor progress and update the mitigation strategies identified in the action plan, the San Luis Obispo County Office of Emergency Services will revisit this plan annually and after each hazard event. The annual review will be conducted by re-convening the HMPC in November of each year. The agenda for these meetings will be coordinated through the Office of Emergency Services and the Hazard Mitigation Planning Committee. At a minimum, the meeting will include the review of the mitigation actions ranked high and medium priority. This plan will be updated, approved and adopted within a five-year cycle as per Requirement §201.6(c)(4)(i) of the Disaster Mitigation Act of 2000 unless disaster or other circumstances (e.g., changing regulations) require a change to this schedule. With the approval of this plan occurring in late-2019, the plan will need to be updated, reviewed by Cal OES and FEMA Region IX, and re-adopted by all participating jurisdictions no later than December of 2024. The county will monitor planning grant opportunities from Cal OES and FEMA for funds to assist with the update. These grants should be pursued as early as 2022, as some grants have a three-year performance period to expend the funds, plus there is no guarantee that the grant will be awarded when initially submitted. This allows time to resubmit the grant in 2023 if needed. 8.2.2 Maintenance and Evaluation Process The planning team will continually observe the incorporation process, evaluation method, updating method, continued public participation, and completion of the action/projects to assure that the planning team and the plan itself are performing as anticipated. By monitoring these processes, the planning team will then be able to evaluate them at the time of the plan update, det ermining if any changes are needed. The LHMP plan update every five years provides an opportunity to determine whether there have been any significant changes in the county that may, in turn, necessitate changes in the types of mitigation actions proposed. New development in identified hazard areas, an increased exposure to hazards, the increase or decrease in capability to address hazards, and changes to federal or state legislation are examples of factors that may affect the necessary content of the LHMP. The plan review provides county officials with an opportunity to evaluate those actions that have been successful and to explore the possibility of documenting potential losses that were avoided due to the implementation of specific mitigation measures. The plan review also provides the opportunity to address mitigation actions that may not have been successfully implemented as assigned. During the five-year plan update process, the following questions will be considered as criteria for assessing the effectiveness and appropriateness of the Plan: ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-5 • Do the goals address current and expected conditions? • Are the goals and objectives consistent with changes in State and Federal policy? • Complete status update on all mitigation projects. What strategies should be revised? • Has the nature or magnitude of risks changed (current and expected conditions)? • Are the current resources appropriate for implementing the LHMP? • Are there implementation problems, such as technical, political, legal or coordination issues with ot her agencies? • Have the outcomes occurred as expected? • Did the county and participating agencies and other partners participate in the plan implementation process as assigned? The County of San Luis Obispo is committed to involving the public in the contin ual reshaping and updating of the Local Hazard Mitigation Plan, as discussed in 8.3. 8.2.3 Disaster Proclamation or Declaration Following a disaster proclamation or declaration, the HMP will be revised as necessary to reflect lessons learned, or to address specific issues and circumstances arising from the event. It will be the responsibility of the Office of Emergency Services to reconvene the Hazard Mitigation Planning Co mmittee and ensure the appropriate stakeholders are invited to participate in the plan revision and update process following declared disaster events. 8.3 Continued Public Involvement DMA Requirement §201.6(c)(4)(iii): [The plan maintenance process shall include a] discussion on how the community will continue public participation in the plan maintenance process. Activities related to public involvement during the 2019 update are documented in Section 3 and Appendix C. Continued public involvement is imperative to the overall success of the plan’s implementation. Efforts will be made to involve the public in the plan maintenance, evaluation, and review process. This includes maintaining a digital version of the plan on the County Office of Emergency Services website for public review. In addition, information on who to contact within the Office of Emergency Services will be posted with the plan. The San Luis Obispo County Office of Emergency Services will maintain a file of comments received for reference during the next five-year update. Any revisions to the plan that may occur as a result of a disaster will also be made public and posted on the county website. The next five-year update process also provides an opportunity to solicit participation from new and existing stakeholders and to publicize success stories from the plan implementation and seek additional public comment. A public hearing(s) or survey to receive public comment on the plan will be held during the plan update period. When the HMPC reconvenes for the update, they will coordinate with all stakeholders participating in the planning process, including those who joined the HMPC after the initial effort, to update and revise the plan. Public notice will be posted and public participation will be invited, at a minimum, through available website postings and press releases to the local media outlets as well as email and social media announcements. ••• Section 8 Implementation and Monitoring San Luis Obispo County Local Hazard Mitigation Plan | October 2019 Page 8-6 Continued public outreach and education is also an aspect of the mitigation strategy in Section 7 of this plan through inclusion of an action to develop and conduct a multi-hazard seasonal public awareness program on an annual basis (Action C.1.1). •••