CC 2014-02-11_09.b. Proposed Ordinance Regarding Stormwater ComplianceMEMORANDUM
TO: · CITY COUNCIL
FROM: TERESA MCCLISH, COMMUNITY DEVELOPMENT DIRECTOR
BY: MIKE LINN, ASSISTANT CITY ENGINEER
SUBJECT: CONSIDERATION OF AN ORDINANCE OF THE CITY COUNCIL OF
THE. CITY OF ARROYO GRANDE REPEALING CHAPTER 13.24 OF
THE ARROYO GRANDE MUNICIPAL CODE AND ADOPTING A NEW
CHAPTER 13.24 GOVERNING GRADING, ADDING A NEW CHAPTER
25 TO TITLE 13 REGULATING ILLEGAL DISCHARGES AND ILLICIT
CONNECTIONS, AND ADDING NEW SECTIONS TO TITLE 16,
CHAPTERS 08 AND 68 REGARDING DESIGN REQUIREMENTS FOR
POST CONSTRUCTION STORMWATER COMPLIANCE
DATE: FEBRUARY 11, ·2014
RECOMMENDATION:
The Planning Commission recommends that the City Council 1) approve the Design
Requirements for Post Construction Stormwater Compliance; and 2)introduce an
ordinance repealing Chapter 13.24 of the Arroyo Grande Municipal Code and adopting
and new Chapter 13.24 governing grading, adding a new Chapter 24 to Title 13
regulating illegal discharges and illicit connections, and adding new sections to Title 16,
Chapters 08 and 68 regarding design requirements for post construction stormwater
compliance.
IMPACT ON FINANCIAL AND PERSONNEL RESOURCES:
Ongoing monitoring of post construction requirements will require additional staff time
for monitoring and inspections. Speqific costs and funding sources have not yet been
identified.
BACKGROUND:
The City is required to adopt regulations in order to comply with the requirements of the
Federal Clean Water Act, the implementing regulations for the National Pollutant
Discharge Elimination System (NPDES), and the California Porter-Cologne Water
Quality Control Act. These requirements provide for the regulation and reduction of
pollutants discharged to waters of the State and United States by extending NPDES
requirements to storm water and urban runoff discharges to and from municipal storm
drain systems.
Item 9.b. - Page 1
CITY COUNCIL
CONSIDERATION OF AN ORDINANCE REPEALING CHAPTER 13.24 OF THE
ARROYO GRANDE MUNICIPAL CODE AND ADOPTING A NEW CHAPTER 13.24
GOVERNING GRADING, ADDING A NEW SECTION TO TITLE 16, CHAPTER 68
REGARDING DESIGN REQUIREMENTS FOR POST CONSTRUCTION STORM
WATER COMPLIANCE, AND ADDING A NEW CHAPTER 25 TO TITLE 13
REGULATING ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS.
FEBRUARY 11, 2014
PAGE 2 OF 5
The City implements these requirements through the Storm Water Management
Program (SWMP) that was originally approved by City Council Resolution 3708 in 2003.
The SWMP requires programs and regulations to manage storm water discharges
within the City and has been updated periodically to stay current with State
requirements. The SWMP has since been revised in accordance with State
requirements and is now referred to as the Storm Water Guidance Document (SWGD).
The SWGD is a requirement of the California Environmental Protection Agency State
Water Resources Control Board Phase II Small Municipal Separate Storm Sewer
System (MS4) Permit. The SWGD includes a series of steps to ensure compliance,
including requirements to update regulations in the City's Municipal Code for
construction activities, post construction management of storm water, illegal discharges
and illicit connections.
The Planning Commission considered the proposed ordinance on February 4, 2014.
The Commission discussion centered around clarifying thresholds that trigger post
construction storm water requirements, specifically, the net increase for impervious
surfaces that are added for a project, and long term maintenance and monitoring of
stormwater controls. Commissioners expressed concern about the impact to
developers during project design and construction as well as property owners for long
term monitoring of structural stormwater controls if they are required onsite.
Recognizing that the City is responsible to comply with stormwater regulations that are
prescribed by the State Water Resources Control Board, the proposed ordinance was
recommended for approval by a 4-0 vote (Commissioner Sperow was absent.)
ANALYSIS OF ISSUES:
Generally, the proposed ordinance includes three parts: 1) a revised grading ordinance
in Chapter 13.24 that incorporate provisions for stormwater, as well as providing an
overall update for the ordinances last updated in 2003; 2) a new Chapter 13.25 to
include regulations for illegal discharges and illicit connections; and 3) provisions in
Code Sections 13.24, 16.08 and 16.68 to require compliance with the City's design
requirements for post construction storm water discharges by approving the guidelines
and incorporating them by reference into the Municipal Code.
Chapter 13.24 Excavation. Grading. Erosion and Sediment Control
The grading ordinance establishes standards to regulate the disturbance of earth during
construction within the City limits, including excavations, filling and compaction,
stormwater runoff, and environmental protection. Notable updates to the new chapter
include:
Item 9.b. - Page 2
CITY COUNCIL
CONSIDERATION OF AN ORDINANCE REPEALING CHAPTER 13.24 OF THE
ARROYO GRANDE MUNICIPAL CODE AND ADOPTING A NEW CHAPTER 13.24
GOVERNING GRADING, ADDING A NEW SECTION TO TITLE 16, CHAPTER 68
REGARDING DESIGN REQUIREMENTS FOR POST CONSTRUCTION STORM
WATER COMPLIANCE, AND ADDING A NEW CHAPTER 25 TO TITLE 13
REGULATING ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS.
FEBRUARY 11, 2014
PAGE30F5
• Requirements for erosion and sediment controls, soil stabilization, dewatering,
source controls, pollution prevention measures and prohibited discharges;
• Mandatory minimum construction site Best Management Practices (BMPs);
• Development of Storm Water Pollution Prevention Plans (SWPPPs) for defined
projects;
• Inspection and compliance; and
• Enforcement mechanisms.
Chapter 13.25 Illegal Discharges and Illicit Connections
The ordinance creates an entirely new chapter to address the following:
• Prohibition of non-stormwater discharges to the storm drain system;
• Regulation of the contribution of pollutants to groundwater, Arroyo Grande Creek
or Meadow Creek by stormwater discharges;
• Prohibition of illicit connections and illegal discharges to the storm drain system;
• Elimination of stormwater connections which are not documented in plans, maps
or equivalent records;
• Spill prevention; and
• Establishment of legal authority to carry out all inspection, surveillance,
monitoring, and enforcement procedures necessary to ensure compliance.
Sections 16.08 and 16.68 Post Construction Stormwater Requirements
The California Regional Water Quality Control Board for the Central Coast Region
(Water Board) adopted Post Construction Requirements in July 2013 and issued Water
Quality Order No. 2013-0001-DWQ to incorporate post-construction controls for MS4
storm water discharges, establishing March 6, 2014 as the date of implementation.
Staff has developed design requirements for post construction storm water compliance
that address the following:
• Performance requirements, based on the development project area, addressing
site design, water quality, and runoff retention;
• Low Impact Development (LID) design standards;
• Hydromodification measures;
• Post-construction best management practice condition assessment;
• Planning and development review process; and
• Alternative compliance.
The most significant changes are new requirements that restrict off-site storm water
runoff to no more than pre-development amounts. Projects sized between 5,000 and
Item 9.b. - Page 3
CITY COUNCIL
CONSIDERATION OF AN ORDINANCE REPEALING CHAPTER 13.24 OF THE
ARROYO GRANDE MUNICIPAL CODE AND ADOPTING A NEW CHAPTER 13.24
GOVERNING GRADING, ADDING A NEW SECTION TO TITLE 16, CHAPTER 68
REGARDING DESIGN REQUIREMENTS FOR POST CONSTRUCTION STORM
WATER COMPLIANCE, AND ADDING A NEW CHAPTER 25 TO TITLE 13
REGULATING ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS.
FEBRUARY 11, 2014
PAGE 40F 5
15,000 square feet of net impervious area are required to retain the 85th percentile of a
24 hour storm event. Projects over 15,000 square feet of net impervious area are
required to retain the 95th percentile. The 95th percentile rainfall event is the event
whose precipitation total is greater than or equal to 95 percent of all 24-hour storms on
an annual basis. This will have a significant impact on costs and the design of new
projects.
One of the most significant impacts on the City is a requirement for ongoing inspection
of storm water retention facilities and equipment. The City proposes to address this
requirement by requiring an operation and maintenance plan for each project detailing
the type of facilities, the inspection criteria, the inspection frequency, and the reporting
format. Upon satisfactory approval of City staff, the document will be recorded with the
property, requiring the property owner to perform the requisite inspections and submit
the reports on a yearly basis to the City. The City will track the inspections and
incorporate the information into the City's yearly reporting to the State Water Resources
Control Board.
Given the impact of these regulations, the City is implementing steps to educate local
developers. A workshop was held on January 23, 2014, attended by local architects,
developers and contractors. Follow-up information will be distributed as it is developed.
Staff desires to work collaboratively with the development community in order to find
ways to implement the new requirements that minimize the impact on new construction
activities.
ALTERNATIVES:
The following alternatives are provided for Council consideration:
Introduce the proposed ordinance;
Amend and introduce the proposed ordinance;
Do not introduce the proposed ordinance; and
Provide direction to staff.
ADVANTAGES:
The City will implement requirements for stormwater management per the Storm Water
Guidance Manual and comply with State requirements.
DISADVANTAGES:
Some requirements, primarily the post construction requirements, will place burdens
and increase costs for developers, as well as require additional staff resources to
monitor, inspect and ensure compliance. However, the City is regulated under the State
Item 9.b. - Page 4
CITY COUNCIL
CONSIDERATION OF AN ORDINANCE REPEALING CHAPTER 13.24 OF THE
ARROYO GRANDE MUNICIPAL CODE AND ADOPTING A NEW CHAPTER 13.24
GOVERNING GRADING, ADDING A NEW SECTION TO TITLE 16, CHAPTER 68
REGARDING DESIGN REQUIREMENTS FOR POST CONSTRUCTION STORM
WATER COMPLIANCE, AND ADDING A NEW CHAPTER 25 TO TITLE 13
REGULATING ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS.
FEBRUARY 11, 2014
PAGE SOF 5
Water Resources Control Board NPDES General Permit for MS4 dischargers and is
thus required to adopt and implement these requirements.
ENVIRONMENTAL REVIEW:
In accordance with the California Environmental Quality Act (CEQA) Guidelines, staff
has determined that the draft Ordinance is exempt per Section 15308 of the Guidelines
which governs actions by regulatory agencies for the protection of the environment.
PUBLIC NOTIFICATION AND COMMENTS:
A notice of Public Hearing was published in the Tribune on Friday, January 31, 2014.
The agenda was posted in front of City Hall on Thursday, February 6, 2014 and both the
agenda and staff report were posted on the City's website on Friday, February 7, 2014.
Item 9.b. - Page 5
ORDINANCE NO.
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY
OF ARROYO GRANDE REPEALING CHAPTER 13.24 OF
THE ARROYO GRANDE MUNICIPAL CODE AND
ADOPTING A NEW CHAPTER 13.24 GOVERNING
GRADING, ADDING A NEW CHAPTER 25 TO TITLE 13
REGULATING ILLEGAL DISCHARGES AND ILLICIT
CONNECTIONS, AND ADDING NEW SECTIONS TO
TITLE 16, CHAPTERS 08 AND 68 REGARDING DESIGN
REQUIREMENTS FOR POST CONSTRUCTION
STORMWATER COMPLIANCE
WHEREAS, the Federal Clean Water Act, National Pollutant Discharge Elimination
System ("NPDES") and the California Porter Cologne Water Quality Control Act provide
for the regulation and reduction of pollutants discharged to waters of the State and
United States by extending NPDES requirements to storm water and urban runoff
discharges to and from the storm drain system; and
WHEREAS, Central Coast municipalities are regulated under the State Water
Resources Control Board NPDES General Permit ("General Permif) for the Discharge
of Storm Water from Small Municipal Separate Storm Sewer Systems ("MS4s"), Order
No. 2013-0001-DWQ, adopted by the State Water Resources Control Board on
February 5, 2013; and
WHEREAS, Order No. 2013-001-DWQ requires the City to address storm water runoff
from development and redevelopment projects through post-construction storm water
management requirements; and
WHEREAS, in order to comply with the General Permit and in order to update and
improve the City's excavation, grading, erosion and sediment control, sections of the
Arroyo Grand Municipal Code require revision ("proposed amendment"); and
WHEREAS, public notice has been given in the time and manner required by State law
and City Code; and
WHEREAS, the Planning Commission of the City of Arroyo Grande reviewed and
considered the proposed amendments at a Public Hearing on February 4, 2014; and
WHEREAS, at its meeting of February 11, 2014, the City Council duly considered all
evidence, including public testimony from interested parties and the evaluation and
recommendations by the Planning Commission; and
WHEREAS, the proposed amendment is consistent with the General Plan; and
Item 9.b. - Page 6
ORDINANCE NO.
PAGE2
WHEREAS, the proposed amendment is internally consistent with other applicable
provisions of the Arroyo Grande Municipal Code; and
WHEREAS, this Ordinance is consistent with protection of the public interest, health,
safety and welfare of the City. This Ordinance is hereby found to be categorically
exempt from environmental review pursuant to CEQA guidelines Section 15308, Actions
by Regulatory Agencies for Protection of the Environment.
NOW, THEREFORE BE IT ORDAINED by the City Council of the City of Arroyo Grande
as follows:
SECTION 1. Recitals. The above recitals are true and correct and are incorporated
herein by this reference.
SECTION 2. Title 13, Chapter 24 of the Arroyo Grande Municipal Code is repealed in
its entirety and replaced with a new Chapter 24 of Title 13, entitled "EXCAVATION,
GRADING, EROSION AND SEDIMENT CONTROL," as set forth in the attached Exhibit
A, which is incorporated herein by this reference.
SECTION 3. Title 13 of the Arroyo Grande Municipal Code is amended to add a new
Chapter 25, entitled "ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS," as set
forth in the attached Exhibit B, which is incorporated herein by this reference.
SECTION 4. Title 16, Chapter 8, Section 010, of the Arroyo Grande Municipal Code is
amended to add a new Subsection T, referencing a new document a copy of which is
attached to this Ordinance and incorporated herein by this reference as Exhibit C, for
incorporation by reference into the Arroyo Grande Municipal Code, as follows:
T. Design Requirements for Post Construction Stormwater
Compliance, as the same may be amended from time to time.
SECTION 5. Title 16, Chapter 68, Section 030 of the Arroyo Grande Municipal Code is
amended to add a new Subsection D, to read as follows:
D. Design Requirements for Post Construction Stormwater
Compliance.
All new development or redevelopment projects that create and/or
replace greater than or equal to 2,500 square feet of impervious
surface (collectively over the entire project site) must comply with
the Design Requirements for Post Construction Stormwater
Compliance adopted by the City and incorporated herein by this
reference.
SECTION 6. Severability. If any section, subsection, subdivision, paragraph, sentence,
or clause of this Ordinance or any part thereof is for any reason held to be unlawful, such
decision shall not affect the validity of the remaining portion of this Ordinance or any part
Item 9.b. - Page 7
ORDINANCE NO.
PAGE3
thereof. The City Council hereby declares that it would have passed each section,
subsection, subdivision, paragraph, sentence, or clause thereof, irrespective of the fact
that any one or more section, subsection, subdivision, paragraph, sentence, or clause be
declared unconstitutional.
SECTION 7. Ordinance Summary. A summary of this Ordinance shall be published in
a newspaper and circulated in the City of Arroyo Grande at least five (5) days prior to
the City Council meeting at which the proposed Ordinance is to be adopted. A certified
copy of the full text of the proposed Ordinance shall be posted in the office of the City
Clerk. Within fifteen (15) days after adoption of the Ordinance, the summary with the
names of those City Council Members voting for and against the Ordinance shall be
published again, and the City Clerk shall post a certified copy of the full text of such
adopted Ordinance.
SECTION 8. Effective Date. This Ordinance shall take effect thirty (30) days after its
adoption.
On motion of Council Member
following roll call vote to wit:
AYES:
NOES:
ABSENT:
, seconded by Council Member
The foregoing Ordinance was adopted this_ day of ______ , 2014.
, and on the
Item 9.b. - Page 8
ORDINANCE NO.
PAGE4
TONY FERRARA, MAYOR
ATTEST:
KELLY WETMORE, CITY CLERK
APPROVED AS TO CONTENT:
STEVEN ADAMS, CITY MANAGER
APPROVED AS TO FORM:
TIMOTHY J. CARMEL, CITY ATTORNEY
Item 9.b. - Page 9
EXHIBIT A
Chapter 13.24 EXCAVATION, GRADING, EROSION AND SEDIMENT CONTROL
-------------------
Sections:
13_24.010 Purpose_
13_24.020 Definitions_
13.24.030 Scope.
13.24.040 Grading Permit Exemptions.
13.24.050 Grading Permit Requirements.
13.24.060 Grading Plan Requirements
13.24.070 Design Standards for Grading.
13.24.080 Temporary Stockpiles
13.24.090 Design Standards for Drainage.
13.24.100 Drainage Plan Requirements
13.24.110 Stormwater Management
--------
13.24.120 Erosion and Sediment Control Plan Requirements.
13.24.130 Stormwater Pollution Prevention Plan (SWPP) Requirements
13.24.140 Design standards for Stormwater Pollution Prevention Plan.
13.24.150 Inspection and Compliance.
13.24.160 Enforcement.
13.24.170 Hazards.
13.24.180 Fees.
13.24.190 Bonds and securities.
13.24.010 Purpose.
The purpose of this chapter is to establish standards to safeguard the public health, safety and general
welfare; minimize erosion and sedimentation; minimize fugitive dust emissions; reduce the harmful effects
of stormwater runoff; encourage groundwater recharge; protect fish and wildlife; reduce hazards to life
and property; reduce drainage problems from new development; prevent environmental damage to public
and private property; and to otherwise protect the natural environment. This Chapter addresses
compliance with the National Pollutant Discharge Elimination System (NPDES) Phase II stormwater
regulations and sets forth local stormwater requirements, to avoid pollution of watercourses with
sediments or other pollutants generated on or caused by surface runoff on or across construction sites.
13.24.020 Definitions.
When used in this chapter, the definitions listed hereunder shall have the meanings as specified in this
section:
"Accelerated erosion" means rapid erosion caused by human-induced alteration of the vegetation, land
surface topography or runoff patterns. Evidence of accelerated erosion is indicated by exposed soils,
active gullies, tills, sediment deposits, or slope failures caused by human activities, including grazing
promoted by human activities.
Item 9.b. - Page 10
"Access and building envelope" means a delineated area within which all land disturbances for
construction of access and/or building will be confined.
"Agricultural Operations" or "Agricultural Production" means any operation occurring on a ranch or farm
directly related to the growing of crops, or raising of fowls or animals for the primary purpose of making a
profit or for a livelihood.
"Applicant" means any person, corporation, partnership, association of any type, public agency or any
other legal entity who submits an application to the building official for a permit pursuant to this chapter.
"Approval" means a written engineering or geological opinion concerning the progress and completion of
the work.
"As-grade" is the surface conditions extent on completion of grading.
"Bedrock" means in-place, solid rock.
"Bench" means a relatively level step excavated into earth material on which fill is to be placed.
"Best Management Practices (BMPs)" are practices, means, methods, measures, devices, structures,
vegetative plantings and/or a combination thereof designed to safely control erosion and sediment so that
construction wastes or contaminants from construction materials, tools and equipment are prevented from
entering the storm drain system.
"Borrow'' means earth material acquired from an off-site or other on-site location for use in grading on a
site.
"Clearing" means the removal or vegetation and debris down to bare soil by any method.
"Civil engineer" means a professional engineer in the branch of civil engineering holding a valid certificate
of registration issued by the State of California.
"Civil engineering" means the application of the knowledge of the forces of nature, principles of
mechanics and the properties of materials to the evaluation, design and construction of civil works.
"Compaction" means the densification of earth and solids or a fill by mechanical means.
"Development permit" means a permit issued for new land use activities, building, grading, land clearing,
subdivision, planned unit development, and/or other project approval process administered by the city.
"Director of Community Developmenr means that person charged with the responsibility of directing all
phases of the planning, building, engineering, and the enforcement of all state statutes and city laws
pertaining to his or her office, or his or her duly authorized representative.
"Director of Public Works" means that person charged the responsibility of coordinating all phases of
administration determining policy and procedures and directing the work of subordinates within the
various divisions encompassed with the Department of Public Works.
"Drainage course" mean a well defined, natural or man-made channel which conveys storm water runoff
either year-round or intermittently.
"Earth material" means any rock, natural soil or fill and/or any combination thereof.
Item 9.b. - Page 11
"Engineering geologist" means a person holding a valid registration as an engineering geologist and
certified in the specialty of engineering geology issued by the State of California under provisions of the
Geologist Act of the Business and Professions Code.
"Engineering geology" means the application of geologic knowledge and principles in the investigation
and evaluation of naturally occurring rock and soil for use in the design of civil works.
"Erosion" means the wearing away of the ground surface by the actions of water, wind, ice, gravity, or a
combination thereof.
"Erosion control specialist" means a person who is registered in the state or by a professional society and
is capable of preparing erosion and sediment control plans. In the event it is the opinion of the building
official such plan requires design of civil works, the specialist must be licensed as a civil engineer in the
state.
"Erosion hazards" means the susceptibility of a site to erode based on soils, condition and steepness of a
slope, rock type, vegetation, and other site factors.
"Erosion, sediment and runoff control planning" means the application of the knowledge of erosion and
sediment control principles and practices in the investigation and evaluation for use in the design of civil
works.
"Erosion sediment and runoff control practices" means methods, measures, devices, structures,
vegetative plantings and/or a combination thereof designed to control erosion and sediment; to safely
contain and/or dispose of storm water runoff; and to stabilize soils and slopes.
"Excavation" means the mechanical removal of earth materials.
"Fill" means the deposit of permitted materials by artificial means.
"Grade" means the vertical location of the ground surface.
"Existing grade" means the grade prior to grading.
"Rough grade" means an approximate elevation of the ground surface conforming to the approved plan.
"Finished grade" means the final grade or surface conditions of the site which conforms to the approved
plan.
"Grading" means any excavation, filling, leveling, or combination thereof (excludes stripping and/or
clearing), all new earthwork that involves one or more of the following activities: excavations, cuts, fills,
leveling, dams, reservoirs, levees, impoundments, diking, dredging, borrow pits, stockpiling, compaction
of fill, or removal of vegetation. Cultivation activities, including disking, harrowing, raking or chiseling,
planting, plowing, seeding, or other tilling are not considered grading and are not regulated under this
ordinance.
"High priority construction site" are those project that are subject to the Construction General Permit, and
projects not subject to the Construction General Permit that meet one or more of the following
circumstances: discharges directly drain to a creek, involves site work on slopes of 20 percent or greater,
involves hillside development on slopes steeper than 10 percent, involves more than 20,000 sf of land
disturbance, include excavation of 100 CY of materials or more, and/or that have grading located within a
geologic study or flood hazard areas. n
Item 9.b. - Page 12
"Key'' means a designed, compacted fill placed in a trench excavated in earth material beneath the toe of
a proposed fill slope.
"Land disturbance" means clearing, stripping, grading or other manipulation of the natural terrain by
manual and/or mechanical means.
"Net impervious area" means the total post-project impervious surface area (including both new and
replacement surface area), minus any reduction in total imperviousness from the pre-project to the post-
project condition.
Net Impervious Area = (New and Replaced Impervious Area) -(Reduced Impervious Area
Credit), where Reduced Impervious Area Credit is the total pre-project to post-project reduction in
impervious area, if any.
"NPDES" means National Pollution Discharge Elimination System, the national program for controlling
discharges under the Federal Clean Water Act.
"One hundred (100) year storm" means there is a 1 in 100 or 1% chance that a storm will reach this
intensity in any given year
"Owner" means the person or persons shown in the county recorder's office as owner of property.
"Permittee" means the owner, contractor, or any person undertaking land disturbance activities upon a
site pursuant to a permit granted by the building official authorizing performance of a specified activity.
"Runoff" means the passage of surface water over ground surface.
"Sediment" means eroded earth material that is carried and/or deposited by water, wind, gravity or ice
and is a major source of water pollution.
"Site" means a lot or parcel of land or contiguous combination thereof, where land disturbance including
erosion control, clearing, grading, or construction are performed, permitted, or proposed.
"Slope" means an inclined ground surface, the inclination of which is expressed as a ratio of horizontal
distance to vertical distance.
"Soil" means naturally occurring superficial deposits overlying bedrock.
"Soil Engineer" means a civil engineer experienced and knowledgeable in the practice of soil engineering.
"Soil engineering" means the application of the principles of soil mechanics in the investigation, evaluation
and design of civil works involving the use of earth materials and the inspection and testing of the
construction thereof.
"Stabilization" means the prevention of erosion to exposed soil.
"Start of construction" means the first land-disturbing activity associated with a construction project.
"Storm Water Control Plan" is a plan, developed by the Regulated Project applicant, detailing how the
project will achieve the applicable Post-Construction Stormwater Management Requirements (for both
onsite and offsite systems).
"Storm Water Pollution Prevention Plan" is a plan that provides for erosion control using the specific best
management practices to control sediment and erosion on a construction site during and after
construction.
Item 9.b. - Page 13
"Stream" means any water course as designated by a solid line or dash and three dots symbol shown on
the largest scale of United States Geological Survey map most recently published.
"Stormwater Control Measures" is any stormwater management measures integrated into project designs
that emphasize protection of watershed processes through replication of pre development runoff patterns
(rate, volume, duration). Physical control measures include, but are not limited to, bioretention/rain
gardens, permeable pavements, roof downspout controls, dispersion, soil quality and depth, minimal
excavation foundations, vegetated roofs, and water use. Design control measures include but are not
limited to conserving and protecting the function of existing natural areas, maintaining or creating riparian
buffers, using onsite natural drainage features, directing runoff from impervious surfaces toward pervious
areas, and distributing physical control measures to maximize infiltration, filtration, storage, evaporation,
and transpiration of stormwater before it becomes runoff.
"Temporary Stockpiles" means soil stockpiled upon a land area for future site development or for
temporary storage for a maximum period of eighteen months.
"10-year storm" means there is a 1 in 10 or 10% chance that a storm will reach this intensity in any given
year
"Terrace" means a relatively level step constructed in the face of a graded slope surface for drainage and
maintenance purposes.
"Topsoil" means loose, pliable, organic and fertile earth materials on top of a soil profile, usually the "A"
horizons.
"Treatment Control Measure" is any engineered system designed to remove pollutants by simple gravity
settling of particulate pollutants, filtration, biological uptake, media absorption or any other physical,
biological, or chemical process.
"Water Pollution Control· Plan (WPCP)" is a plan that accompanies erosion and sedimentation control
plans, unless exempted by the Director or the Public Works Director. Best Management Practices (BMPs)
shall be in compliance with CASQA handbook or equivalent. A project SWPPP also can serve as the
WPCP.
"Unstable soil" means soil which is not competent to support other soil or fill, to support structures, or to
satisfactorily perform the other functioning for which the soil is intended.
13.24.030 Scope.
This chapter sets forth standards, including the incorporation of Best Management Practices (BMPs),to
control excavation, grading, erosion and sediment; requires control of all existing and potential conditions
of accelerated erosion; establishes administrative procedures for issuance of permits; and provides for
approval of plans and inspections during construction and maintenance. All activities subject to
subdivision map requirements and/or building permits shall meet these standards. This Chapter also
provides for the approval of plans and inspection of grading construction and BMPs. In the event of any
conflict between the provisions of this Chapter and state law, the more restrictive requirement shall apply.
13.24.040 Grading Permit Exemptions
Note: While the activities under this section are exempted from a grading permit for the purposes of this
City's ordinance, the owner and/or applicant should understand that permits may be required by other
regulatory agencies, including, but not limited to, the California Department of Fish and Wildlife , Regional
Water Quality Control Board, Army Corps of Engineers, U.S. Fish and Wildlife Service, or the California
Department of Forestry (Cal Fire). Additionally, grading projects involving work within a State or County
right-of-way may require encroachment permit approval.
Item 9.b. - Page 14
No person shall do any land disturbance work without first obtaining a permit from the Director of
Community Development. A grading permit shall be obtained where grading is to occur meeting the
definition set forth in Section 13.24.050 (Grading). Activities that do not constitute grading as defined in
this Chapter, or are exempt from grading permits, may be subject to other applicable sections in this
ordinance. This includes requirements, such as preparation and approval of an erosion and
sedimentation control· plan, drainage plan, and/or stormwater pollution prevention plan. In granting any
permit in compliance with this Chapter, the Director of Community Development and, where provided, the
Director of Public Works, may impose conditions as necessary. These conditions may include requiring a
licensed contractor to perform the work or a licensed professional (e.g. civil engineer, geotechnical
engineer, etc.) to prepare plans or technical reports in order to prevent creation of a nuisance or a hazard
to public health, public safety, or public or private property, or to assure conformity to the City's General
Plan. The following grading does not require a grading permit. Exempt grading activities must employ
appropriate sedimentation and erosion control measures:
a. Isolated area: grading in an isolated, self-contained area if there is no danger to private or public
property;
b. Emergency work: work necessary to preserve life or property; provided, however, that when
emergency work is performed under this section, the person performing it shall report the
pertinent facts relating to the work to the Director of Community Development within fifteen (15)
days after commencement of the work and shall thereafter obtain a permit pursuant to Section
13.24.050 and perform such work as may be determined by the Director of Community
Development to be reasonably necessary to correct any erosion or conditions with a potential to
cause erosion as a result of the emergency work;
c. Excavation: an excavation which does not exceed fifty (50) cubic yards and is less than one foot
in depth, does not create a cut slope higher than five feet and steeper than two to one (2:1 );
d. Fill: a fill containing only permitted materials less than one-foot deep, placed on natural terrain
slope flatter than five to one (5:1 ), and does not exceed fifty (50) cubic yards on any one site,
including stockpiles, does not alter or obstruct a drainage course, will not be used for structural
support or roadways and the area graded or filled does not exceed eleven thousand (11,000)
square feet (one-quarter acre). This exemption shall not apply to a fill within a riparian zone;
e. Basements and footings: an excavation below finished grade for basements and footings of a
building, retaining wall or other structure authorized by a valid building permit. This shall not
exempt any fill except as provided under subsection D of this section, made with the material
from such excavation or exempt any excavation having an unsupported height greater than five
feet after the completion of such structures;
f. Cemeteries: cemetery graves; excavation, or fill within a property used or to be used for cemetery
purposes is exempt. Grading that is intended to support structures or that will affect natural
drainage patterns do not fall under this exemption;
g. Refuse disposal: refuse, individual and/or community sewage disposal sites controlled pursuant
to other regulations;
h. Wells and utilities: excavations for wells, tunnels or utilities;
i. Exploratory investigations: excavations under the direction of a soils engineer or engineering
geologist where such excavation is to be returned to the original condition within forty-five (45)
days after the start of work;
j. Clearing an area of eleven thousand (11,000) square feet (one-quarter acre) or less on five
percent slopes or less;
Item 9.b. - Page 15
k. Agricultural: normal routine farming activities necessary to manage land, crops and/or animals for
food production;
I. Mining, quarrying, excavating, processing, stockpiling of rock, sand, gravel, aggregate or clay
where established and provided for by law, provided such operations are conditioned by other
permits to preclude discharge of sediments offsite and provided such operations do not affect the
lateral support or increase the stresses or pressure upon any adjacent or contiguous property; '
m. Grading activities shall receive all necessary approvals from other City, state, or federal agencies,
regardless of whether the activity is exempt under this Chapter;
n. Activities exempted under this section are still required to incorporate all reasonable measures to
ensure against erosion and sedimentation both during and after such activities. In all cases, any
grading activities which could result in a hazardous condition are not exempt from grading permit
requirements. A hazardous condition exists when activities create a hazard to life and limb,
endanger property, adversely affect the safety, use or stability of a public right-of-way or drainage
channel, or create a significant environmental impact.
13.24.050 Grading Permit Requirements
A grading permit is required in any of the following cases, unless the project qualifies for an exemption or
constitutes agricultural grading as set forth in Section 13.24.040:
1. 50 cubic yards. The amount of material, measured cumulatively (adding together all proposed
earthwork) for any of the above mentioned activities exceeds 50 cubic yards.
2. Work in a watercourse. The amount of material, measured cumulatively (adding together all
proposed earthwork) for any of the above mentioned operations exceeds 20 cubic yards and
involves altering or obstructing a drainage way or watercourse.
3. Removal of vegetation. Projects which would involve more than one acre of vegetation
removal on a site.
4. Temporary Stockpile. Soil stockpiled upon a land area for future site development or for
temporary storage as set forth in Section 13.24.080.
Vegetation removal is calculated based on the total area of a site which will lack soil cover (i.e. "bare soil")
at any given time. Areas subject to previous vegetation removal are not included in this calculation where
permanent revegetation has already achieved a minimum of 70 percent coverage.
All projects subject to a grading permit must submit an erosion and sediment control plan which includes
the rationale used for selecting BMPs. The erosion and sediment control plan may be substituted by a
'SWPPP if the project requires one. The erosion and sediment control plan must require operators of
construction sites to minimize the discharge of pollutants to the MS4 through the installation,
implementation or maintenance of BMPs consistent with the California Storm Water Quality Association
(CASQA) BMP Handbook or equivalent.
Note: The grading thresholds specified in Subsections 1 and 2 above are to be measured cumulatively for
each project. A project may not be broken down into smaller components with the intention of avoiding a
grading permit. Activities progressing towards a common endeavor are considered a single project.
Item 9.b. - Page 16
13.24.060 Grading Plan Requirements.
All applications for a grading permit shall be accompanied by a grading plan consistent with this Section.
A. Professionals qualified to prepare grading plans.
1. Grading Plans may be prepared by anyone who can accurately provide the necessary information
for the application, grading plan, erosion and sedimentation control plan, drainage plan, and
stormwater pollution prevention plan review. This may include the applicant, a draftsperson,
designer, certified sedimentation and erosion control specialist or licensed individuals who are
normally involved with a project such as a civil engineer, surveyor, architect, or landscape
architect. Should additional information be required due to unique physical characteristics of the
site, this may require that information be prepared by the appropriate licensed professional (at the
discretion of the Director of Community Development).
2. Grading Plans prepared for an Engineered Grading Plan (as defined by Subsection C) may be
prepared only by professionals licensed by the State of California to prepare grading and
drainage plans. The assistance of other professionals approved by the Director of Community
Development is encouraged. These professionals may include landscape architects, soil
engineers, geologists, engineering geologists, certified sedimentation and erosion control
specialists, botanists, biologists, and archaeologists.
B. Grading Plan Content. A grading plan shall be legible and accurately drawn to scale using standard
drafting techniques. Plans shall be of sufficient clarity to indicate the nature and extent of the work
proposed and show in detail that they will conform to the provisions of this Chapter and all relevant
codes and regulations. Plans shall include, but not be limited to, the following information unless
waived by the Director of Community Development:
1. General site information.
a. The name, address, and phone number of the owner and the person by whom the plans were
prepared.
b. A description of the land upon which the work is to be performed, including Assessor's Parcel
Number, street address, tract, block, and lot number.
c. An accurate location map with enough detail to find the site in the field and detailed directions
to the site.
d. An accurate site plan that delineates the limits of grading activities.
e. A written scope of work, including references to any documents associated with the scope of
work. Where grading was previously unpermitted, discussion on background and history of
the grading activities shall be included.
2. Topography and earthwork quantities.
a. Existing or natural ground contours, and proposed ground contours at intervals of no more
than two feet for area to be graded and five feet for the remainder of site. On rural parcels
exceeding 80 acres, existing and proposed contours shall be shown at two foot intervals for
area to be graded, and the remainder of site at 20 foot intervals. The latest USGS
topographic maps may be used as a source of information for the 20 foot intervals.
Item 9.b. - Page 17
b. An estimate of the volume of earth to be moved, expressed in cubic yards, verified and
stamped by the engineer of record. Calculations shall be provided to support the estimate.
c. An estimate of the surface area of earth to be moved, expressed in square feet, verified and
stamped by the engineer of record. Calculations shall be provided to support the estimate.
d. An estimate of the total area of site disturbance, expressed in square feet. This total shall
include all vegetation removal in addition to soil disturbance.
e. An estimate of total area in square feet of native vegetation to be removed.
3. Cuts and fills.
a. Cuts and fills shall be limited to the minimum amount necessary to establish the proposed
use. Specify amounts of cut and fill. Identify location of site{s) to receive fill, showing area and
depth of fill. Identify location of borrow site{s) and depth of borrow. Whenever possible, cut
and fill should be balanced on the site.
1) If fill materials are imported to the site, provide information regarding the proposed
source{s) and amount of material. If the source changes due to other materials becoming
available, this information shall be provided to the Director of Community Development.
2) If excavated materials are exported provide statement of amount, method of disposal,
proposed location{s), and details on applicable permits.
3) If permits are necessary for the site providing the fill material or receiving excavated
material, provide evidence that permits have been issued for that site.
b. An estimate of the maximum and minimum vertical depth of cuts and fills, expressed in feet
and cut and fill slope ratios.
c. Any required retaining walls or other means of retaining cuts or fills. Additionally, provide
details and calculations of the retaining walls, drainage devices, and all other protective
structures to be constructed as part of the grading permit.
4. Finish elevations.
a. Elevation of the finish floor of the garage or other parking areas.
b. Ground and finish floor elevations at the base of building or structure corners.
c. Elevations of the edge of pavement or road at driveway entrance.
d. Elevations of the top of wall and bottom of footing of proposed retaining walls.
5. Site improvements and features.
a. The location of all existing and proposed surface and subsurface drainage ways and
drainage systems on the site and adjacent property which may affect or be affected by the
proposed project.
b. The location of all existing and proposed buildings, structures, easements, groundwater
recharge areas, wells or sewage disposal systems on site, and the approximate location of
these items on adjacent property that are within 100 feet of the property boundary or which
may affect or be affected by the proposed project. Show spot elevations at corners of
existing and proposed buildings or structures and lots where proposed grading will occur.
Item 9.b. - Page 18
c. Location, description, type or topographic description of existing rock outcropping natural
feature, vegetation, individual oak trees, wooded areas or trees that are five inches or
greater in diameter measured 4.5 feet above ground level proposed for disturbance and/or
removal. Botanical, archaeological, or biological surveys prepared by a qualified individual
may be required where warranted. Show centerline of streams and flood plain lines, if
applicable. Clearly identify on the plan the boundary and general characteristics of areas
within which no disturbance will occur.
6. Soils.
a. A copy of a soils map and soils descriptions covering the project site and adjacent properties
(available for free through the USDA Natural Resources Conservation Service online).
b. When required by the Director of Community Development, each application for a grading
permit shall be accompanied by two sets of supporting data consisting of a civil engineering
report, soil engineering report, engineering geology report, erosion and sedimentation control
report, and/or any other reports necessary. In many instances this information may be shown
on the face of the plan.
c. Reports shall be prepared by qualified professionals with experience in report preparation
and grading plan implementation. Recommendations included in the reports that are
approved by the Director shall be incorporated into the grading plan. (See Subsection C,
Engineered Grading Requirements).
d. Clearly show groundwater recharge methods that have been incorporated into the project
design.
e. All applicable dust control measures.
C. Engineered Grading Plan requirements. When required pursuant to Subsection C.1, the grading
plan shall be prepared and signed and sealed by a qualified, registered civil engineer or other qualified
professional licensed by the state to perform such work, and shall include specifications covering
construction, inspection and material requirements in addition to the information required in compliance
with Subsection B. Additionally, those items required by Subsections C.2 through C.4 shall accompany
the grading plans.
1. When required. Engineered grading is required when one or more of the following circumstances
exist:
a. The grading will involve 5,000 cubic yards or more (cumulative).
b. The grading involves site work on slopes of 20 percent or greater.
c. The proposed grading is located within a Geologic Study Area or Flood Hazard area.
d. The Director of Community Development has cause to believe that geologic hazards may
be involved.
2. Site and drainage report. The site and drainage report, shall include, but not be limited to:
a. The date the report was prepared and the name, address, and phone number of firm or
individual who prepared the report.
b. Hydrology calculations showing maximum peak discharges of water runoff for 2 through 10-
and 100-year storm frequencies and comparison of runoff with and without project. Hydraulic
calculations for existing downstream runoff conveyance systems that will be impacted by the
proposed project runoff.
Item 9.b. - Page 19
c. Summary of the groundwater recharge methods that have been incorporated into the project
design.
d. Inspection and approval to establish lines and grades, design criteria for corrective measures,
including the required safe storm drainage capacity of channels both on and off-site.
e. Soils, geology, or civil engineer's opinions and recommendations concerning adequacy of site
to be developed by the proposed grading.
f. Sequence and type of recommended inspections.
3. Geotechnical report. The geotechnical report shall be prepared by qualified person license to do
geotechnical work and contain, but need not be limited to, all the following information:
a. The date the report was prepared and the name, address and phone number of firm or
individual who prepared the report.
b. Data regarding the nature, distribution, and strength of existing soils.
c. Data regarding the nature, distribution, and strength of soil to be placed on the site, if any.
d. Conclusions and recommendations for grading procedures.
e. Conclusions and recommended designs for interim soil stabilization devices and measures
for permanent soil stabilization after construction are completed.
f. Design criteria for corrective measures including buttress fills, when necessary.
g. Identification of existing cuts and fills on site, recommended measures for compaction, slope
stability and other factors affecting suitability for support of a structure.
h. Engineer's opinions and recommendations concerning adequacy for the intended use of site
to be developed by the proposed grading as affected by soils engineering factors, including
the stability of slopes, foundation recommendation, soil design criteria, liquefaction,
expansive soil, loose or soft soils, areas of unknown problems, undocumented fill, cut/fill,
unusual loading, shallow ground water or springs, and landslides.
i. Sequence and type of recommended inspections.
4. Engineering geology report. The engineering geology report shall be prepared by qualified
person license to do geotechnical work and comply with protocol approved by the Department of
Planning and Building and shall contain, but need not be limited to, the following information:
a. The date the report was prepared and the name, address, and phone number of firm or
individual who prepared the report.
b. An adequate description of the geology of the site.
c. Conclusions and recommendations regarding the effect of geologic conditions on the
proposed development.
d. An opinion on the adequacy for the intended use of site to be developed by the proposed
grading, as affected by geologic factors.
e. Need for underground drainage devices or opportunities for underground recharge devices.
f. Sequence and type of recommended inspections.
Item 9.b. - Page 20
g. If the proposed grading is for a habitable structure, and the geologist has identified evidence
of recent fault ruptures occurring near the proposed structure, additional geological
information will be necessary. The guidelines suggested in the California Division of Mines
and Geology Notes #49 or subsequent additions shall be used to prepare this supplemental
report.
When the Director of Community Development has cause to believe that geologic hazards may be
involved, the regular grading operation shall be required to conform to engineered grading requirements.
13.24.070 Design Standards for Grading.
A. Grading standards.
1. Excavation standards. All excavations are to be conducted in compliance with the provisions of
Section J106 of the California Building Code and the following standards:
a. No excavation shall be made with a cut face steeper in slope than two horizontal to one
vertical, except under one or more of the following conditions.
1) The Director of Community Development may permit an excavation to be made with a cut
face steeper than two horizontal to one vertical if the applicant provides a slope stability
analysis prepared by a geotechnical engineer or engineering geologist that the material
making up the slope of the excavation and the underlying earth material is capable of
standing on a steeper slope, and a certified soil and erosion control specialist or other
qualified professional indicates, in writing, that either it is feasible to mitigate erosion and
sedimentation impacts and that successful revegetation of the site can be accomplished
or that due to the nature or composition of the cut slope, erosion and sedimentation
measures and revegetation are unnecessary.
2) A retaining wall or other approved support which also mitigates visual impacts of the
device is provided to support the face of the excavation.
b. The Director of Community Development may require an excavation to be made with cut face
flatter in slope than two horizontal to one vertical if a slope stability analysis or other
appropriate method of review indicates that the material in which the excavation is to be
made is such that the flatter cut slope is necessary for stability, safety, or to prevent erosion
and sedimentation and stormwater impacts.
c. No cut slope shall exceed a height of 25 feet without intervening terraces having a minimum
width of six feet. These terraces shall be vertically spaced at intervals of 25 feet except that
for slopes less than 40 feet in vertical height the terrace shall be approximately at mid-height.
Suitable access shall be provided to permit cleaning and maintenance. The Director of
Community Development may modify this requirement because of geologic or other special
conditions.
d. The border of all cut slopes shall be rounded off to a minimum radius of five feet to blend with
the natural terrain.
e. All cut slopes shall be within parcels under common ownership unless written permission is
granted by the adjacent owner.
2. Fill standards. All fills are to be conducted in compliance with the provisions of Section J107 of
the California Building Code Appendix J and the following standards:
Item 9.b. - Page 21
a. No fill shall be made which creates any exposed surface steeper in slope than two horizontal
to one vertical, except under one or more of the following conditions:
1) A retaining wall or other approved support is provided to support the face of the fill which
also mitigates visual impacts of the device.
2) The Director of Community Development may permit a fill to be made which creates an
exposed surface steeper in slope than two horizontal to one vertical (2:1) if a
geotechnical engineering report demonstrates that slope stability will be ensured. The
geotechnical engineer shall certify that the strength characteristics of the material to be
used in the fill are such as to produce a safe and stable slope and that the areas on
which the fill is to be placed are suitable to support the fill. Additionally, a certified soil and
erosion control specialist or other qualified professional shall indicate in writing that it is
feasible to prevent erosion and sedimentation impacts, and successful revegetation of
the site can be accomplished. All such reports are subject to the approval of the Director
of Community Development.
b. The Director of Community Development may require that fill be constructed with an exposed
surface flatter than two horizontal to one vertical (2:1) if a slope stability analysis or other
appropriate method of review indicates that such flatter surface is necessary for stability,
safety, or to prevent erosion and sedimentation impacts.
c. Unless specified as a non-structural land reclamation, erosion control, or agricultural fill, all
fills shall be placed, compacted, inspected, and tested in compliance with the following
provisions:
1) The natural ground surface shall be prepared to receive fill by removing vegetation, non-
complying fill, topsoil and other unsuitable· materials. The surface shall be scarified to
provide a bond with the new fill and where slopes are steeper than five horizontal to one
vertical (5:1) and the height is greater than five feet, by benching into sound bedrock or
other competent material as determined by the soils engineer. The bench under the toe
of a fill on a slope steeper than five horizontal to one vertical (5:1) shall be at least 10 feet
wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain
shall be provided. When fill is to be placed over a cut, the bench under the toe of fill shall
be at least 10 feet wide, but the cut shall be made before placing the fill. The soils
engineer, engineering geologist, or both, shall certify that the bench is a suitable
foundation for the proposed fill.
2) Except as otherwise permitted by the Director of Community Development, no rock or
similar irreducible material with a maximum dimension greater than six inches shall be
buried or placed in fills. No organic material shall be permitted in structural fills. The
Director of Community Development may permit placement of larger rock when the Soils
Engineer properly devises a method of placement, continuously inspects its placement,
and approves the fill stability. The following conditions shall also apply:
a. Prior to issuance of the grading permit, potential rock disposal areas shall be
identified on the grading plan.
b. Rock sizes greater than six inches in maximum dimension shall be 10 feet or
more below grade, measured vertically.
c. Rocks shall be placed so as to assure filling of all voids with well-graded soil.
3) A fill shall be spread in a series of horizontal lifts as specified by th~ geotechnical
engineer or other approved professional approved by the Director of Community
Development. The distribution of material throughout each layer shall be free of lenses,
Item 9.b. - Page 22
pockets or layers of material differing substantially in texture or gradation from the
surrounding material. All material shall be compacted into a fill of uniform moisture and
density as specified in Subsection A.2.c.(4).
4) All fills shall be compacted to a minimum of 90 percent of maximum density as
determined by ASTM D 1557-(latest edition) or other approved testing method giving
equivalent test results. Field density shall be determined by ASTM D 1556-(latest edition)
or other equivalent methods approved by the Director of Community Development.
5) A field density test, as herein provided, shall be taken for each 24 inches of fill, or portion
thereof, measured vertically from the lowest point of the area to be filled, and for each
200 cubic yards of fill placed unless a variation is recommended by the Soils Engineer
and approved by the Director of Community Development. In addition, in the case of a
subdivision, field density tests shall be taken on lots which receive fill based upon the
recommendations of a soils engineer.
6) All fills regulated by this Chapter shall be tested for relative compaction by a qualified
geotechnical testing agency. Final reports, including a letter certifying compliance with
the terms of this Chapter, and the grading permit, setting forth densities, relative
compaction and other fill characteristics shall be prepared and signed by a Geotechnical
Engineer. This report shall be submitted to and approved by the Director before any final
approval of the fill is given and before any foundation construction begins except for the
digging of trenches and placing of reinforcing steel.
d. Fills toeing out on natural slopes which are steeper than two horizontal to one vertical
shall not be permitted unless evaluated and approved by a geotechnical engineer or
engineering geologist.
e. The border of fill slopes shall be rounded off to a minimum radius of five feet to blend
with the natural terrain.
3. Grading setback standards. Cut and fill slopes shall be set back from site boundaries in compliance
with the provisions of Section J108 of the 2013 California Building Code Appendix J and the following
standards:
Item 9.b. - Page 23
H/2 BUT 2 FT. MIN.
AND 20 FT. MAX.
PA•
I
TOE
SLOPE
CUT OR FILL
SLOPE
H
TOP OF
SLOPE
HIS BUT 2 FT. MIN.
AND 10 FT. MAX.
PA"
I .
NATURAL OR
FINISH GRADE
H
Under_§.
~30
Over 30
* PA =Permit Area Boundary -Lot line(s) or permit area boundary if the
permit area is smaller than the lot involved
Figure 1 -Grading Setbacks
TABLE NO. 70
REQUIRED SETBACKS FROM PERMIT AREA BOUNDARY (IN FEET}
isETBACKS
ia lb1
I I
I j 1 10
)H/2 jH/5
I 15 16 1-1-
1Additional width may be required for interceptor drain.
Figure No. 2
Item 9.b. - Page 24
a. General. Setback dimensions shall be horizontal distances measured perpendicular to the
site boundary. Setback dimensions shall be as shown in Figure 1.
b. Stream and Riparian Setback. Tops and toes of cut and/or filled slopes shall be set back far
enough to prevent encroachment upon streams, flood plains, or channels, or body of
standing water to provide and maintain an undisturbed protective strip between the grading
and the riparian corridor. This strip shall have sufficient filter capacity to prevent degradation
of water quality, as determined by the erosion and sediment control specialist and approved
by the building official. If it is determined that the filter capacity of the protective strip is
insufficient, or development activity will encroach upon riparian zones, additional setback
distance and/or erosion control practices may be required.
c. Retaining Walls. Retaining walls, when keyed into stable foundations and capable of
sustaining the design loads, may be used to reduce the required cut and fill setbacks when
recommended by the civil or soils engineer, or engineering geologist and approved by the
building official.
d. Top of cut slope. The top of the cut slopes shall not be closer to a site boundary line than
one fifth of the vertical height of cut with a minimum of two feet and a maximum of 10 feet.
The setback may need to be increased for any required interceptor drains or maintenance
easements. The Director may approve adjustments as a condition of the permit, as required
by individual site conditions.
e. Toe of fill slope. The toe of fill slopes shall not be closer to the site boundary line than one-
half the height of the slope with a minimum of two feet and a maximum of 20 feet. Where a fill
slope is to be located near the site boundary and the adjacent off-site property is developed,
or site conditions warrant, special precautions shall be incorporated in the work as the
Director of Community Development deems necessary to protect the adjoining property from
damage as a result of such grading. These precautions shall include, but are not limited to
the following:
1) Additional setbacks.
2) Provisions for retaining or slough walls.
3) Mechanical or vegetative treatment of the fill slope to minimize erosion.
4) Provisions for the control of surface waters.
5) Provisions for maintenance access.
f. Modification of slope location. The Director of Community Development may approve
alternate setbacks. The Director of Community Development may require an investigation
and recommendation by a qualified engineer, engineering geologist, or erosion control
specialist to demonstrate that the intent of this Section has been satisfied.
g. Distance from property line. No cut or fill shall be made which is sufficiently close to the
property line to endanger any adjoining public or private property or structures without
supporting and protecting such property or structures from any settling, cracking, or other
damage which might result.
h. Other Restrictions and/or Minimums. Other requirements may also be increased or
relaxed upon review by the building official if he or she finds the deviations consistent with
safety and stability and to provide access for slope maintenance and drainage.
Item 9.b. - Page 25
4. Landfonn alterations within public view corridors._ Grading, vegetation removal, and other
landform alterations shall be minimized on sites located within areas determined by the Director of
Community Development to be a public view corridor from collector or arterial roads. Where feasible,
contours of finished grading are to blend with adjacent natural terrain to achieve a consistent grade
and appearance.
5. Grading near watercourses. Grading, dredging or diking shall not alter any intermittent or perennial
stream, or natural body of water shown on any USGS 7-1/2 minute map, except as permitted through
approval of a City drainage plan and a streambed alteration permit from the California Department of
Fish and Wildlife issued under Sections 1601 or 1602 of the Fish and Wildlife Code. Watercourses
shall be protected as follows:
a. Watercourses shall not be obstructed unless an alternate drainage facility is approved.
b. Fills placed within watercourses shall have suitable protection against erosion during flooding.
c. Grading equipment shall not cross or disturb channels containing live streams without siltation
control measures approved by the Director of Community Development in place.
d. Excavated materials shall not be deposited or stored in or alongside a watercourse where the
materials can be washed away by high water or stormwater runoff.
13.24.080 Temporary Stockpiling Permits.
The Director of Community Development may issue a permit for temporary stockpiling (storage) of earth
conforming to the following:
A. Requirements. Temporary stockpiling shall:
1) Not exceed 7,000 cubic yards and cover less than one acre in area;
2) Be on a single lot;
3) Not located on or across or affect any surface water body or divert existing drainage courses;
4) Not have a fill bank in excess of 6 feet measured vertically from the toe of the slope to the top
of the slope;
5) Not exceed 18 months from the date any stockpiled material is initially placed to the date all
material is removed;
6) Not result in exposed fill slopes steeper in average slope than two horizontal to one vertical,
including benches and roundings to ensure stability and reduce visual impacts;
7) Install and maintain measures to protect against erosion and instability and ensure that runoff
water leaving the premises will not contain sand, silt or other debris;
8) Conform to the setbacks identified under Section 13.24.070.A.3;
9) Place materials only on areas previously excavated or disturbed which contain no significant
habitat value, designated scenic area, or mapped geological hazard; and
10) Involve only materials for use on the site, not for export, sales or borrow operations.
B. Application and Plan. The application shall be signed by the owner of the land on which the earth is
to be stockpiled and be accompanied by a stockpiling plan, grading plan or improvement plan. The
application shall include the following:
1) A certification that the fill material is for use exclusively on the site;
2) A description of the proposed ultimate use of the stockpiled material;
3) A vicinity sketch showing:
a) property lines and the location of all structures within 100 feet of the proposed
stockpile and adjacent properties if within 15 feet of the property line;
Item 9.b. - Page 26
b) contour lines showing the topography of the existing ground with a maximum
contour interval of 5 feet, the quantity of proposed fill;
c) elevations, dimensions, location, extent and square footage of the total footprint
of the area proposed to be covered by the stockpiled material;
d) all drainage devices, walls, cribbing, dams, stormwater protection best
management practices or other protective devices to be constructed, including all
temporary construction erosion and sediment control devices;
e) a map of the drainage area of the land tributary to the site; and
f) dust control measures.
C. Security. At the time of permit issuance, the applicant shall enter in to an agreement, secured by a
cash deposit, to assure the future permanent placement or removal of the stockpiled material.
13.24.090 Design Standards for Drainage
A. Drainage standards. Site development shall have no adverse impacts on adjacent and downstream
locations. If adverse impacts are identified, off-site erosion, sediment and flood control improvements
to the drainage way will be required to eliminate the adverse impacts. Designs for site area drainage
and terraces shall be consistent with the Low Impact Development {LID) requirements set by the
RWQCB and the following minimum standards:
1. Design and construction. Drainage systems and facilities subject to drainage plan review and
approval that are to be located in existing or future public rights-of-way are to be designed and
constructed as set forth in the latest edition of the Public Works Department's Public
Improvement Standards, or as per the project's conditions of approval. Applicants may request an
adjustment pursuant to the Public Improvement Standards in order to allow for a design that is
more compliant with LID practices. Other systems and facilities subject to drainage plan review
and approval are to be designed in accordance with good engineering practices. The design of
drainage facilities in new land divisions and other new development subject to Minor Use Permit
or Conditional Use Permit approval shall maximize groundwater recharge through on-site or
communitywide stormwater infiltration measures. Examples of such measures include
constructed wetlands, vegetated swales or filter strips, small percolation ponds, subsurface
infiltration basins, infiltration wells, and recharge basins. Where possible, recharge basins shall
be designed to be available for recreational use.
2. Natural channels and runoff. Proposed projects are to include design provisions to retain
natural drainage patterns and, when required, limit peak runoff to pre-development levels. To the
maximum extent feasible, all drainage courses shall be retained in, or enhanced to appear in, a
natural condition, without channelization for flood control. On downhill sites, encourage drainage
easements on lower properties so that drainage can be released on the street or other
appropriate land area below.
3. Best Management Practices (BMPs). All new development subject to drainage plan review shall
use BMPs to address polluted runoff. BMPs shall be consistent with the guidance found in
documents such as the LID Handbook. Such measures shall include, but not be limited to:
minimizing the use of impervious surfaces {e.g., installing pervious driveways and walk~ays);
directing runoff from roofs and drives to vegetative strips before it leaves the site; and/or
managing runoff on the site {e.g., percolation basins); and other Low Impact Design {LID)
techniques. The installation of vegetated roadside drainage swales shall be encouraged and, if
used, calculated into BMP requirements. The combined set of BMPs shall be designed to treat
stormwater runoff up to and including the 85th percentile storm event.
4. Runoff volume. Runoff conveyance systems shall be capable of carrying the computed runoff
volume from a 25-year frequency storm or greater if deemed necessary by the Director of
Community Development. This may be reduced to a 10-year storm for small watersheds.
Item 9.b. - Page 27
5. Interceptors. Concrete ditches, bio-swales or other approved methods capable of intercepting
surface runoff waters shall be installed along the top of all cut slopes where the tributary drainage
area has a slope 10 percent or greater and a horizontal projection greater than 40 feet.
Interceptor drains shall be paved with a minimum of three inches of concrete or gunite and
reinforced. They shall have a minimum depth of twelve (12) inches and a minimum paved width
of thirty (30) inches measured horizontally across the drain. The slope of drain shall be approved
by the Director of Community Development. Energy dissipaters may be required by the Director
of Community Development.
6. Berms. Berms or drainage divides at least one foot high and three feet wide at the base shall be
constructed at the top of all fill slopes where runoff would be directed towards the top of fill.
Berms, ditches, interceptor drains, or swales shall be constructed at the top of cut and filled
slopes for protection against water runoff. Paved interceptor drains shall be installed along the top
of all cut slopes where the tributary drainage area above slopes towards the cut and has a
drainage path greater than forty (40) feet measured horizontally.
7. Over side drains. Over side drains shall be of concrete or corrugated metal pipe having a
diameter required by runoff calculations, but not less than eight inches, and shall be aligned so as
to minimize velocity at discharge points. Alternate designs, such as LID methods, approved by
the Director of Community Development may be permitted.
8. Inlets. Inlets shall be constructed of galvanized iron, or approved equivalent, and shall be
provided with overflow structures.
9. Outlets. Outlet structures shall be provided with approved velocity reducers, diversion walls, rip-
rap, concrete aprons or similar energy dissipaters where necessary and aligned to minimize
downstream erosion and reasonably maximize recharge at discharge points, and shall be
approved by the Director of Community Development.
10. Culverts. Culvert size and materials shall be determined by the civil engineer in accordance with
standard design criteria and as approved by the building official. Minimum diameter shall be
eighteen (18) inches.
11. Terraces. Terraces at least six feet in width shall be established at not more than thirty (30) foot
vertical intervals on all cut or fill slopes to control surface drainage and debris except that where
only one terrace is required, it shall be at mid-height. For cut or fill slopes greater than sixty (60)
feet and up to one hundred twenty (120) feet in vertical height, one terrace at approximately mid-
height shall be twelve (12) feet in width. Terrace widths and spacing for cut and fill slopes greater
than one hundred twenty (120) feet in height shall be designed by the civil engineer and approved
by the Director of Community Development. Suitable access shall be provided to permit proper
cleaning and maintenance. Swales or ditches on terraces shall have a minimum gradient of five
percent and must be paved with reinforced concrete not less than three inches in thickness or an
approved equal paving. They shall have a minimum depth at the deepest point of one foot and a
minimum paved width of five feet. A single run of swale or ditch shall not collect runoff from a
tributary area exceeding thirteen thousand (13,000) square feet (projected) without discharging
into a down drain.
12. Dispersal structures. An approved drainage dispersal structure shall be constructed wherever it
is necessary to convert channel flow to sheet flow.
13. Sensitive habitat and groundwater protection. Runoff from roads and development shall not
adversely affect sensitive habitat, groundwater resources and downstream areas, and shall be
treated to remove floatable trash, heavy metals and chemical pollutants as necessary prior to
discharge into surface or groundwater.
Item 9.b. - Page 28
14. Groundwater recharge methods. New development shall identify all methods to enhance
groundwater recharge.
15. Impervious surfaces. New development shall be designed to minimize the amount of impervious
surfaces in order to maximize the amount of on-site infiltration.
16. Rain gutters. Approved rain gutters shall be provided to receive all roof water and dispose of the
water in a groundwater enhancing and non-eroding manner where the Director of Community
Development determines it to be necessary because of steepness of slope or presence of
erodible materials. Direct connection of rain gutter outlets to impervious surfaces shall be
minimized.
17. Building site drainage. All graded building pads shall slope a minimum of five percent for ten
feet to an approved drainage device, or as approved by the Director of Community Development.
The drainage device shall be an approved system which conducts the water to a street, recharge
area or drainage way. The top of footing stems or finish floor, if a concrete slab, shall extend
above the top of street curb or inlet to the drainage device by a minimum of six inches plus two
per cent of the distance from the footing to the drainage device or curb. The Director of
Community Development may allow two percent to be used, if, because of terrain or soils, five
percent is not reasonably attainable or necessary. ·
18. Capacity of drainage devices. On graded sites, the Director of Community Development may
require that drainage devices calculated to convey runoff from a 25-year frequency storm or
greater be installed, if deemed necessary to prevent erosion, to conduct stormwater around
buildings or structures and to the nearest recharge area, drainage way, or as approved by the
Director of Community Development.
19. Appearance of drainage or recharge devices. Where drainage devices are highly visible from
the street or located in the public viewshed, they shall be shielded from view, if practical. Where
visible, drainage devices shall be compatible with the character of the area and the existing
topography. Exposed concrete overside drains are prohibited within these situations unless a
visual analysis indicates the prohibition to be unnecessary. If they are visible, the size shall be the
minimum necessary to handle drainage and ensure ability to maintain all drainage devices which
collect from the slopes, and shall convey drainage by means of underground pipes or rock-lined
ditches or other approved materials to blend with the natural topography in character, color and
design. Transitions from natural drainage courses to developed areas shall be accomplished with
comparable landscaping and grading to blend with existing topography. Detention, retention, or
recharge basins shall be designed as a visual and/or recreational amenity within a project
whenever practical.
20. Groundwater Recharge. Groundwater recharge elements must be included in the project design
to mitigate the impacts on recharge caused by the reduction in the permeability of soil areas on
the site, except when any of the following site characteristics exist:
1. High groundwater in the area limits the effectiveness of recharge efforts or enhancing
groundwater recharge would create additional problems related to high groundwater.
2. The entire site being developed is shown to contain impervious soils that would not benefit
from recharge efforts.
3. There is a known geologic instability that would be negatively impacted by increased
groundwater recharge.
4. It can be demonstrated that no additional runoff will occur from the development.
5. Federal or state regulations prohibit recharge.
Item 9.b. - Page 29
B. Groundwater recharge. All areas on the project site that will become impervious or will have their
soil permeability impaired (such as compaction of soil under an all weather driveway) must be
mitigated to the maximum extent practicable with recharge enhancement elsewhere on the parcel.
Offsite mitigation is a secondary alternative.
1. Areas subject to flooding. Buildings or structures are not permitted in an area determined by
the Director of Community Development to be subject to flood hazard by inundation, overflow,
high velocity flows or erosion, except where the buildings or structures comply with the standards
in Section 16.44.050, and provisions are made to eliminate identified hazards to the satisfaction
of the Public Works Director. These provisions may include providing adequate drainage facilities,
protective walls, suitable fill, raising the floor level of the building or structure, or other means. The
building and other structures (including walls and fences) shall be placed on the site so that water
or mud flow will not be a hazard to on-or off-site structures or adjacent property. In the
application of this standard, the Director of Community Development shall enforce as a minimum
the current federal flood plain management regulations as defined in the National Flood
Insurance Program authorized by United States Code Title 42, Section 4001-4128 and contained
in Title 44 of the Code of Federal Regulations, Part 59 et seq., which are hereby adopted and
incorporated into this Title by reference as though they were fully set forth here. ·
2. Design of flood proofing measures. Flood proofing measures required by the Director of
Community Development shall be designed by a licensed architect or registered civil engineer.
3. Sub-drains. The Director of Community Development may require the installation of approved
sub-drains in areas where underground water is anticipated.
4. Runoff computations. Runoff computations may be made by the "rational method" except where
specific methods for calculating individual residential retention basins have been adopted or with
the approval of the Director of Community Development.
5. Alternate designs. Alternate designs which provide equivalent safety and are approved by the
Public Works Director may be used in lieu of those contained in this Section.
6. Hydromodification control. If the Director of Community Development has determined that the
project could cause off-site erosion or adverse impacts to beneficial uses as a result of an
increase in runoff rates and/or duration, the project shall incorporate hydromodification control
measures in compliance with Low Impact Development (LID) Handbook requirements.
13.24.100 Drainage Plan Requirements
A. Requirements. Drainage plans shall be prepared and submitted for review and approval by the
Director of Community Development, where a project:
1. Increases or decreases runoff volume or velocity leaving any point of the site beyond those that
existed prior to site disturbance activities; or
2. Involves a land disturbance (grading, or removal of vegetation down to duff or bare soil, by any
method) of more than 20,000 square feet; or
3. Will result in an impervious surface of more than 20,000 square feet; or
4. Is subject to local ponding due to soil or topographic conditions; or
Item 9.b. - Page 30
5. Is located in an area identified by the Director of Community Development as having a history of
flooding or erosion that may be further aggravated by or have a harmful effect on the project or
adjoining properties; or
6. Is located within a Flood Hazard (FH) combining designation; or
7. Is located over a known high recharge area identified by the Director of Community Development;
or
8. Involves land disturbance or placement of structures within 100 feet of the top bank of any
watercourse shown with a blue line on the most current USGS 7% minute quadrangle map; or
9. Involves hillside development on slopes steeper than 10 percent; or
10. May, by altering existing drainage, cause an on-site erosion or inundation hazard, or change the
off-site drainage pattern, including, but not limited to any change in the direction, velocity, or
volume of flow.
B. Drainage plan content. Drainage plans shall be legible and accurately drawn, at an appropriate
scale that will enable ready identification and recognition of submitted information. Director of
Community Development may require drainage plans to be prepared by a registered civil engineer.
1. Basic drainage plan contents. A drainage plan shall include the following information about the
site:
a. Flow lines of surface waters onto and off the site.
b. Existing and finished contours at two-foot intervals or other topographic information required
by the Director of Community Development.
c. Building pad, finished floor and street elevations, existing and proposed.
d. Location and graphic representation of all existing and proposed natural and manmade
drainage facilities for storage or conveyance of runoff, including drainage swales, ditches,
culverts and berms, sumps, sediment basins, channels, ponds, storm drains and drop inlets.
e. Proposed flood-proofing measures were determined to be necessary by the Director of
Community Development and in accordance with Federal Emergency Management Agency
(FEMA) requirements.
f. For projects where the Director of Community Development or Public Works Director
determines that increased discharge rates and durations could result in off-site erosion or
other impacts to beneficial uses, the project shall incorporate appropriate hydromodification
measures as identified in the Low Impact Development (LID) Handbook. Such measures
shall be clearly depicted on the drainage plan.
2. Engineered plan content. In addition to the information required by Subsection B.1, engineered
drainage plans are to include:
a. An evaluation of the effects of projected runoff on adjacent properties and existing drainage
facilities and systems.
b. A map showing the drainage area and hydraulic calculations showing the facilities flow
carrying capacities for the design storm event and justifying the estimated runoff of the area
served by any drain. Include design discharges and velocities for conveyance devices, and
storage volumes of sumps, ponds, and sediment basins based on the design storm.
Item 9.b. - Page 31
c. Estimates of existing and increased runoff resulting from the proposed improvements and
methods for reducing velocity of any increased runoff.
d. Methods for enhancing groundwater recharge that have been incorporated into the project
design or an explanation of non-necessity of groundwater recharge for this site
13.24.110 Stormwater Management
Purpose. The requirements in this Section are intended to reduce pollutant discharges to the Maximum
Extent Practicable and to prevent stormwater discharges from causing or contributing to a violation of
receiving water quality standards, also known as post-construction stormwater management. These
requirements also emphasize protecting and, where degraded, restoring key watershed processes to
create and sustain linkages between hydrology, channel geomorphology, and biological health necessary
for healthy watersheds. Maintenance and restoration of watershed processes impacted by stormwater
management is necessary to protect water quality and the beneficial uses of surface and groundwater.
A. Regulated Projects. Regulated projects include all new development or redevelopment projects,
both discretionary and ministerial, that create and/or replace at least 2,500 square feet of
impervious surface (collectively over the entire project site).
B. Stormwater Control Plan (SWCP) Required. Prior to acceptance of an application for a
construction permit, grading permit, land use permit or subdivision application associated with a
Regulated Project, as defined in this section, the applicant shall submit a Stormwater Control
Plan. The SWCP shall demonstrate compliance with all applicable Post Construction
Requirements for the Central Coast Region, adopted by the Central Coast Regional Water
Quality Control Board under Order R3-2013-0032 and comply with the City's Design
Requirements for Post Construction Compliance adopted by the City and incorporated herein by
this reference, on file in the Community Development Department.
1. Site Design Checklist. The SWCP for all projects subject to this Section shall demonstrate that
the following design strategies have been pursued in order to reduce runoff:
a. Limit disturbance of creeks and natural drainage features.
b. Minimize compaction of highly permeable soils.
c. Limit clearing and grading of native vegetation at the site to the minimum area needed to
build the project, allow access, and provide fire protection.
d. Minimize impervious surfaces by concentrating improvements on the least-sensitive
portions of the site, while leaving the remaining land in natural, undisturbed state.
e. Implement at least one of the following strategies:
1) Direct roof runoff into cisterns, rain barrels, underground storage, or a similar
mechanism for reuse.
2) Direct roof runoff onto vegetated areas safely away from building foundations and
footings, consistent with the California Building Code.
3) Direct roof runoff from sidewalks, walkways, and/or patios onto vegetated areas
safely away from building foundations and footings, consistent with the California
Building Code.
Item 9.b. - Page 32
4) Direct runoff from driveways and/or uncovered parking lots onto vegetated areas
safely away from building foundations and footings, consistent with the California
Building Code.
5) Construct bike lanes, driveways, uncovered parking lots, sidewalks, walkways, and
patios with permeable surfaces.
C. Stormwater Quality Standards. Stormwater Control Plans shall be reviewed for consistency
with the post-construction stormwater control standards identified in Central Coast Regional
Water Quality Control Board Order R3-2013-0032, or subsequent amendments thereto.
Standards contained in this order include, but are not limited to, the following:
1. Parking lots. Parking lots with an area of 5,000 square feet or more, or 25 parking
spaces or more, shall minimize potential for oil, grease, and other water insoluble
hydrocarbons from vehicle drippings and leaks from entering the stormwater conveyance
system. Plans shall provide for the following:
a. Treat to remove oil and petroleum hydrocarbons; and
b. Ensure adequate operation and maintenance of treatment systems, particularly
sludge and oil removal and system fouling and plugging prevention control. At a
minimum, this shall include a maintenance program which is funded and carried out
by the property owner.
2. Maintenance. Long-term maintenance of BMPs shall be established through the
recordation of a maintenance agreement and/or Covenants, Conditions, and Restriction
(CC&Rs), unless the project does not include structural or treatment control BMPs. This
agreement shall be recorded prior to or concurrent with issuance of a construction permit.
In order to verify that BMPs will be maintained, the agreement shall do the following:
a. Designate responsibility. Identify the party who is responsible for long-term
maintenance of structural and treatment control BMPs.
b. Address transfer of responsibility. Address how BMPs will be maintained once
property has been transferred to private landowners, a homeowners association, or a
public entity.
c. Reference educational materials. Educational materials shall be required to
accompany the first deed transfer. These materials shall provide information on what
stormwater management facilities are present, signs that maintenance is needed,
how the necessary maintenance can be performed, and assistance that the applicant
can provide to the new landowner. The transfer of this information shall also be
required with any subsequent sale of the property.
d. Address operations and maintenance reporting. Address how and when long-
term operations and maintenance will be verified and reported to the City.
13.24.120 Erosion and Sedimentation Control Plan Requirements
A. Requirements. An erosion and sedimentation control plan shall be required year-round for the
following types of projects:
1. Construction and grading. All construction and grading permit projects.
Item 9.b. - Page 33
B. Water Pollution Control Plan (WPCP). All erosion and sedimentation control plans shall be
accompanied with a complete WPCP application, unless exempted by the Director or the Public
Works Director. Best Management Practices {BMPs) shall be in compliance with CASQA handbook
or equivalent. A project SWPPP also can serve as the WPCP.
C. Erosion and sedimentation control plan content. An erosion and sedimentation control plan shall
address pre-construction, during construction, and post-construction measures. Measures shall be in
place to control erosion and sedimentation prior to the commencement of grading and site
disturbance activities unless the Director of Planning and Building or the Public Works Director
determines temporary measures to be unnecessary based upon location, site characteristics or time
of year.
Plans may be incorporated into and approved as part of a grading or drainage plan, but must be
clearly identified as an erosion and sedimentation control plan. Erosion and sedimentation control
plans are reviewed and approved by the Director of Planning and Building or the Public Works
Director. The plan shall be prepared by a certified sediment and erosion control specialist, a
registered civil engineer, registered architect or landscape architect, certified California nurseryman,
licensed landscape contractor, Resource Conservation District or USDA Natural Resources
Conservation Service Specialist, or other qualified persons acceptable to the Department of Planning
and Building with competence and experience in erosion control plan preparation and
implementation.
The plan shall consist of graphic and narrative information of sufficient clarity to indicate the nature,
extent, location and placement recommendations {including installation procedures and
requirements) of the erosion and sedimentation control measures proposed and show in detail that
they will conform to the provisions of this Chapter. The location of all practices, methods and devices
shall be shown on the grading plan, or on a separate plan at the discretion of the Director. If separate,
it shall be attached to the grading plan used in the field. The plan shall contain, but need not be
limited to, all the following information unless some of the information is waived by the Director of
Community Development or the Public Works Director as not needed for the review of a particular
site and its characteristics Grading limits shall be graphically defined on the plan and staked out
before site disturbance begins.
1. Proposed pre-construction, during construction, and post-construction methods and a
description of the practices to be used for cut or fill slopes to prevent erosive surface runoff.
2. A statement signed by the individual preparing the plan certifying that the amount of site
disturbance proposed has been reduced to the maximum extent practicable complies with all
applicable standards in this Chapter.
13.24.130 Stormwater Pollution Prevention Plan (SWPPP) Requirements
A. Requirement Criteria. Unless exempted by the RWQCB, a Stormwater Pollution Prevention Plan
{SWPPP) is required prior to issuance of grading and/or construction permits, and/or prior to approval
of subdivision improvement plans, for a project that involves clearing, grubbing, grading, · or
disturbance to the ground such as stockpiling or excavation that:
1. Results in site disturbance of one acre or more of land area; or
2. Results in site disturbance of less than one acre if the activity is part of a larger common plan of
development that encompasses one acre or more of site disturbance.
13.24.140 Design Standards for Stormwater Pollution Prevention Plan.
Item 9.b. - Page 34
Stormwater pollution prevention standards. Projects requiring a SWPPP shall comply with the
standards outlined in SWRCB General Construction Permit Number CAS000002, or any subsequent
General Construction Permits that amend or replace Permit CAS000002. The SWPPP must utilize BMPs
consistent with the California Storm Water Quality Association (CASQA) BMP Handbook or equivalent.
13.24.150 Inspections and Compliance
Excavation, grading, filling, clearing and erosion control work for which a permit is required shall be
subject to inspection by the Community Development Department (Planning, Building and Engineering
Divisions) to assure compliance with the approved plans. The Director of Community Development may
require supervision, regular inspection, and special testing be performed and certified by the civil
engineer (or other professional) who prepared the approved plan; and the civil engineer shall also be
responsible for the inspection and approval of work within his or her area of technical specialty. This
responsibility shall include, but need not be limited to, inspection and approval as to the establishment of
line, grade and drainage of the development area.
The Director of Community Development may also require special supervision, inspection and testing be
performed by an independent, approved testing agency to ensure compliance with this chapter, the
permittee's permit concerns, and/or in accordance with the provisions of Section 306 of the California
Building Code and Section 13.24.060 of this Chapter .
. Approved plans for grading, vegetation removal work, and erosion and sedimentation control (or SWPPP
if required) bearing the stamp ~f the City of Arroyo Grande Engineering or Building Departments shall be
maintained at the site during the progress of the work. The Director of Community Development shall
inspect or provide for adequate inspection of the project by appropriate professionals at the various
stages of the work requiring approval, and at any more frequent intervals necessary to determine that
adequate control is being exercised by the professional consultants.
Notification. The permittee shall notify the Director of Community Development two working days prior to
the beginning of the operation authorized by the permit, two working days before the project is ready for
final inspection, and one complete working day prior to any other inspection or testing requested by the
permittee.
Right of Entry. Filing for a permit under this chapter constitutes a grant of permission for the City to enter
the permit area for the purpose of administering this chapter from the date of the application to the
termination of the erosion control maintenance period. If necessary, the Director of Community
Development shall be supplied with a key or lock combination, or permitted to install a city lock.
1. Required Inspections. Inspections for a grading permit shall be made as provided herein and work
shall not continue until approval to proceed has been granted following the requested inspection. The
permit holder shall be responsible for requesting inspection through the Director of Community
Development as follows:
a. Pre-site inspection to determine the suitability of the proposed project and the existing
and potential erosion and sediment hazards.
b. Pre-construction meeting. At the Director of Community Development discretion, a pre-
construction meeting may be required due to site characteristics, required mitigation
measures, or complexity of the proposal. Qualified professionals may need to be in
attendance.
c. Pre-construction stormwater inspection. When the permit holder is ready to begin
work, but before any grading or vegetation removal has occurred, inspect and review
erosion and sedimentation control BMPs with permit holder to ensure all necessary
sediment controls are in place. Subsequent site inspections may be conducted at any
time during the life of the project to determine compliance with the erosion and
Item 9.b. - Page 35
sedimentation control plan and/or stormwater pollutior:i prevention plan and to ensure that
BMPs are being maintained, are effective as installed and to verify that no pollutants of
concern are being discharged into receiving water bodies.7
d. Excavation inspection. After the excavation is started, but before the vertical depth of
the excavation exceeds ten feet.
e. Fill inspection. After the placement of fill is started, but before the vertical height of the
fill exceeds ten feet, and at two foot vertical increments thereafter unless waived by the
Director of Community Development. In addition, the fill must be inspected by a qualified
lab requiring testing for each two feet of fill, or as defined in the soils report.
f. Key and bench inspection. After keys and benches are excavated, but before fill is
placed.
g. Rough grade inspection. When all rough grading has been completed, including
terraces, swales, and other drainage devices.
h. Post-construction stormwater inspection. When all work has been completed, all
disturbed areas of the construction site have been stabilized, and all long-term
(permanent) stormwater pollution prevention and erosion and sedimentation control
measures have been installed. Consistent with the General Construction Permit (where
applicable) and City requirements, in order for the post-construction stormwater
inspection to be approved, all soil disturbing activities shall have been completed and one
of the following shall have been met:
1) A uniform vegetative cover of 70 percent coverage has, been established. In arid
areas where native vegetation covers less than 100 percent of the surface, the 70
percent coverage criterion shall be proportionally adjusted (i.e. where native
vegetation covers 50 percent: 0.50 x 0.70 = 0.35 -35 percent); or
2) Equivalent stabilization measures have been employed (e.g. fiber blankets, channel
liners, mulch, etc.).
3) All temporary erosion and sediment control measures that are no longer needed
have been removed.
i. Final inspection. When all work, including installation of drainage structures, other
protective devices, planting, slope stabilization and all erosion control measures has
been completed in accordance with the final approved plan and the required reports have
been submitted to the Director of Community Development and accepted as complete.
j. Other inspections. In addition to the inspections above, such other inspections of any
work to ascertain compliance with the provisions of this chapter and other laws and
regulations as may be required by the Director of Community Development including
requirements of the NPDES permit of the City of Arroyo Grande for its stormwater
discharges. A licensed landscape architect, qualified biologist, archeologist, agricultural
advisor, or other qualified professional may be required to be present during inspections.
k. Rainy season inspection. During the rainy season (between October 15 and April 15),
inspections shall be conducted to verify compliance with required BMPs based on
potential for threat to water quality, as determined by the Director of Community
Development. Criteria to be considered include area of disturbance, earthwork quantities,
and proximity to watercourses. Based on this assessment, a threat priority will be
assigned an inspections shall occur as follows:
Item 9.b. - Page 36
Construction Site
Priority Low Medium Hiah
Frequency of Once or twice during Twice or more during Monthly, and prior
Inspection the rainy season the rainy season to rain events with
50% chance or
more of producing
rain.
High priority construction sites are defined as all projects subject to the Construction General Permit and
a subset of projects not subject to the Construction General Permit that meets one or more of the
following circumstances: discharges directly drain to a creek, involves site work on slopes of 20 percent or
greater, involves hillside development on slopes steeper than 10 percent, involves more than 20,000 sf of
land disturbance, include excavation of 100 CY of materials or more, and/or that have grading located
within a geologic study or flood hazard areas.
Low priority construction sites include all those that consist primarily of interior improvements only ....
Medium construction site priority are those that are neither defined as low or a high construction site
priority.
A. Exposure of work. Whenever any work for which inspections are required is covered or concealed
by other work without having been inspected, the Director of Community Development may require
that such work be exposed for examination.
B. Post Construction and other Inspections.
1. Best Management Practices {BMPs). Inspectors of the Engineering Department may inspect for
adequate installation and functionality of BMPs prescribed by the erosion and sedimentation
control plan or SWPPP at any time throughout the year. The inspectors may identify maintenance
and repair needs on the site with the permit holder, or permit holder's agent, to ensure
compliance with the minimum requirements of BMPs.
2. Corrective action. If the Director of Community Development determines by inspection that
grading as authorized is likely to endanger public health, safety or welfare in the deposition of
debris on any public street, or interfere with any existing drainage course, the Director of
Community Development may require that reasonable safety precautions be taken to remove
such likelihood of danger. Written notice to comply shall be provided to the permit holder allowing
no more than ten days for corrections to begin unless an imminent hazard to the public health,
safety or welfare exists, in which case the corrective work shall begin immediately.
C. Special Reports. Periodic reports by a geotechnical engineer, an engineering geologist, or other
qualified professional, certifying the compaction or acceptability of all fills may be required. These
shall include, but not be limited to, inspection of cleared areas and benches prepared to receive fill
and removal of all unsuitable materials, the bearing capacity of the fill to support structures, the
placement and compaction of fill materials, and the inspection of buttress fills, subterranean drains,
cut slopes and similar devices.
D. Inspection by Others.
1. Where the nature of the project, type of soils, geologic conditions or drainage dictate that special
engineering, geotechnical engineering, or geological inspections are necessary to prevent danger
to public health, safety or welfare, the Director of Community Development may require the
permit holder to retain one or more of the following:
Item 9.b. - Page 37
a. A civil engineer: to supervise and coordinate all field surveys and the setting of grade stakes
in conformity with the plans, to check elevation of grades, inclination of slopes, installation of
drainage structures and other matters related to the geometric design of the work, including
the design of revised or modified plans, if necessary.
b. A geotechnical engineer: to provide either periodic or continuous inspection of all soils work,
including grading and compaction.
c. An engineering geologist: to provide geological inspections.
d. Resource Conservation District: to provide inspections related to drainage and soil erosion
prevention.
E. Inspection process
1. Grading shall not be commenced until the permit holder or agent has signed an Inspection
Agreement to allow the inspector to make the required entries thereon regarding inspection of the
work.
2. The permit holder, agent, or contractor shall have an approved set of grading, drainage and
erosion and sedimentation control plans, and stormwater pollution prevention plan (if required),
on the site and available at all times while work is in progress until final approval. The plans and
specifications shall also include any mitigation measures approved by the Environmental
Coordinator (if applicable).
3. In the absence of a specific work site designation, the Director of Community Development may
require the site to be surveyed and staked by a civil engineer or land surveyor licensed by the
State of California so that the proper location of the work on the lot or parcel may be determined.
4. Inspections for a grading permit shall be made as provided herein and work shall not continue
until approval to proceed has been granted, following inspection. The permit holder shall be
responsible for notifying the Engineering Division at least 24 hours prior to the time when an
inspection is necessary.
5. Where the nature of the project, type of soils, geologic condition, drainage, or weather conditions
dictate that special engineering, geotechnical engineering, geological, or erosion and
sedimentation or asbestos control inspections are necessary to prevent danger to public health,
safety or welfare, the Director of Community Development may require the permit holder to retain
a licensed professional qualified to perform the following:
a. Supervise and coordinate all field surveys and the setting of grade stakes in conformity with
the plans; to check elevations or grades; inclination of slopes; elevation and grades of
drainage structures and other matters related to the geometric design of the work, including
the design of revised or modified plans and "as-graded" plans, if necessary.
b. Provide either periodic or continuous inspection of soils work, including grading and
compaction.
c. Provide geological inspections.
d. Inspect all erosion and sedimentation runoff control measures and revegetation practices
applied to the site.
6. Where the nature of the project dictates that special environmental monitors be required, the
environmental review process and mitigation measures shall establish the manner and timeframe ·
in which this review shall occur. In these instances, the Director of Community Development may
Item 9.b. - Page 38
require the permit holder to retain a qualified professional to perform the work identified from
these measures.
7. If the civil engineer, geotechnical engineer, geologist, or sediment and erosion control specialist
find that the work is not being performed in substantial conformity with this Chapter or the
approved plans and specifications, notice shall be given to the person in charge of the grading
work and to the Director of Community Development. No work shall proceed unless and until the
issuance of such written notice from the Director of Community Development that work may
proceed.
8. If the Director of Community Development determines by inspection that grading as authorized is
likely to endanger sensitive resources, public health, safety, or welfare in the deposition of debris
on any public or private property, or interfere with any existing drainage course, the Director of
Community Development shall require that effective precautions be taken to remove such
likelihood or danger. Written notice to comply shall be given to the permit holder allowing no more
than 10 days for corrections to begin unless an imminent hazard to sensitive resources or the
public health, safety or welfare exists, in which case the corrective work shall begin immediately.
9. Final inspection, as required in this Chapter, shall be made to the satisfaction of the Director of
Community Development.
13.24.160 Enforcement
A. Stop Work Order.
1. Whenever any grading, construction or earthwork is being done contrary to the provisions of
any approval or of any rule, regulation, law or ordinance, or whenever approval was based
upon purposeful misinformation or misrepresentation, or whenever the public health, safety or
welfare is endangered, or any work is not in compliance with the plans or permits approved
for the project, the Director of Community Development shall issue a written notice or stop
work order on the portion of the work affected. Such notice or order to stop work shall be
served upon the property owner and any persons engaged in the doing or causing such work
to be done, and any such persons shall forthwith stop such work until authorized by the
Director of Community Development to proceed with the work in writing. The notice or order
shall state the reason for the notice and no work shall be done on that portion until the matter
has been corrected and approval obtained from the Director of Community Development. The
order may specify actions necessary to restore the site or provide temporary measures for
erosion and sedimentation control until the stop work order has been removed.
2. It shall be unlawful for any person to commence or continue any work regulated under the
provisions of this Chapter in violation of, or contrary to any stop work notice or stop work
order issued in compliance with this Section, except in conformity to the terms of such order
or notice of order, or until relief from such order is obtained from the Director of Community
Development or, upon appeal, from the City Council. ·
B. Violations and penalties.
1. Any person, firm, contractor, or corporation whether as principal, agent, employee or
otherwise who shall commence, construct, enlarge, alter, repair, or maintain any grading,
excavation, or fill, or cause the same to be done, contrary to or in violation of any provision of
this Chapter is subject to civil and/or criminal action. The City Council hereby declares that
any grading done contrary to the provisions of this Code is unlawful and a public nuisance.
The offense may be filed as either an infraction or a misdemeanor at the discretion of the City
of Arroyo Grande City Attorney.
Item 9.b. - Page 39
2. In addition to any penalties prescribed, the Director of Community Development shall submit
a written report to the appropriate state licensing or professional registration board or society
in cases where contractors or professional consultants violate the provisions of this Code.
3. Any person violating any of the provisions of this chapter shall be guilty of a separate offense
for each and every day or portion thereof during which any violation of any of the provisions
of this chapter is committed, continued, or permitted.
4. Paying a fine or serving a jail sentence shall not relieve any person from responsibility for
correcting any condition which violates any provision of this Title.
C. Injunctions, civil remedies, penalties, and costs.
1. Any person, firm, contractor, or corporation whether as principal, agent, employee or
otherwise who shall commence, construct, enlarge, alter, repair, or maintain any grading,
excavation, or fill, or causes the same to be done, contrary to or in violation of any provision
of this Chapter shall be subject to injunction against such activity and shall be liable for a civil
penalty for each day that the violation continues to exist.
2. When the City Council determines that any person has engaged or, is engaged, in any act(s)
which constitute a violation of provision(s) of this Chapter, or order issued, the City Attorney
or the City Council may make application to the Superior Court for an order enjoining such
acts or practices, or for an order directing compliance, and upon a showing that such person
has engaged in any such acts or practices, a permanent or temporary injunction, restraining
order, or other order may be granted by a Superior Court having jurisdiction over the cause.
3. Any person, firm, or corporation whether as principal, agent, employee or otherwise who shall
commence, construct, enlarge, alter, repair, or maintain any grading, excavation, or fill, or
causes the same to be done, contrary to or in violation of any provision of this Chapter shall
be liable for and obliged to pay to the City of Arroyo Grande for all costs incurred by the City
in investigating and obtaining abatement or compliance, or which are attributable to or
associated with any enforcement or abatement action, whether such action is administrative,
injunctive or legal; and for all damages suffered by the City, its agents, officers or employees
as a result of such violation or efforts to enforce or abate the violation.
4. Until all costs, fees and penalties assessed under this Chapter are paid in full, no final
approval, Certificates of Completion, Certificates of Compliance, Certificates of Occupancy,
land use permits or subdivision maps shall be issued or approved by the Planning and
Building Department, Public Works Department, other City agencies, or the City Council.
5. In determining the amount of civil penalty to impose, the Court shall consider all relevant
circumstances, including but not limited to, the extent of the harm caused by the conduct
constituting the violation; the nature and persistence of such conduct; the length of time over
which the conduct occurred; the assets, liabilities and net worth of the persons responsible,
whether corporate or individual; any corrective action taken by the persons responsible; and
the cooperation or lack of cooperation in efforts toward abatement or correction.
D. Additional actions and remedies.
1. Notice of Violation Recordation. Whenever the Director of Community Development
determines that work has not been completed in accordance with a permit or the plans and
specifications relating thereto, or whenever the Director of Community Development
determines that work has been done without.the required permit, the Director of Community
Development may record a notice of violation. The owner(s) of the property, as revealed by
the assessment roll on which the violation is situated, and any other person responsible for
the violation shall be notified of the recordation, if their address is available. If the responsible
Item 9.b. - Page 40
party fails to act in response to written notification of the Director of Community Development,
an erosion problem may be declared a public nuisance and may be abated according to
procedures in the Municipal Code. Where there is an emergency condition of erosion or
sediment damaging a waterway, marsh, other body of water, or private or public property, the
Director of Community Development may have the necessary corrective work done and then
bill the responsible party or place a lien against the offending property.
2. Any person who violates any provision of this Chapter or who violates any stop work order or
notice may also be in violation of the Federal Clean Water Act and/or the State Porter-
Cologne Act and may be subject to prosecution under those Acts, including civil and criminal
penalties.
3. Any person who knowingly makes any false material statement, representation, or
certification in any record or other document submitted or required to be maintained by this
Chapter or the General Construction Permit is subject to civil or criminal action.
4. Any person who violates any order issued by the City for violation of the provisions of this
Chapter regulating or prohibiting discharge of both stormwater and non-stormwater, and
which causes, or threatens to cause, pollutants to enter the City's stormwater conveyance
system shall be liable for such amounts that the City may be fined by the State Water
Resources Control Board (SWRCB) or Regional Water Quality Control Board (RWQCB), or
the amount of any civil liability imposed on the City for non-compliance with the SWRCB
permits.
E. Additional Procedures for Unauthorized Grading.
1. Additional Procedures to Remedy Unauthorized Grading Without a Permit-Finding and
Declaration. The City Council finds and declares that unauthorized grading without a permit
often results in soil erosion, drainage, visual and other destructive long-term impacts which
are not satisfactorily alleviated or corrected by the usual enforcement procedures, such as
criminal violations or judicial proceedings concerning public nuisances. Further, such grading
often causes harm unique to the graded parcel and the properties surrounding it, and the
long-term correction measures for each such unauthorized grading requires detailed
consideration and formulation, usually after formal public hearings.
a. Upon discovery of unauthorized grading without a permit, the Director of Community
Development shall, where feasible, contact the owner of the property upon which the
grading occurred, and the person who did the grading. If the building official and the
owner and contractor can agree within thirty (30) days upon a remedial program which
can be accomplished in no more than ninety (90) days, no further city action shall be
required at that time. The Di~ector of Community Development shall obtain a cash bond
from the owner or contractor, payable upon request, and a right-of-entry form signed by
the owner to guarantee the city's right to do the remedial program as agreed if not done
by the owner or contractor within the agreed time period.
b. If the Director of Community Development cannot reach such a satisfactory agreement,
he or she shall, within thirty (30) days, submit a detailed report and recommendations to
the City Manager and City Council requesting the initiation of formal council proceedings
under the city's nuisance abatement ordinance to abate the public nuisance created on
the premises by the unauthorized grading. The object of such proceedings shall be the
ordering of corrective measures, subject to the city's power to correct the problem and
place a lien upon the real property for all costs of correction. For purposes of the
nuisance abatement proceedings, the City Council declares that unauthorized grading
without a permit is a public nuisance, per se.
Item 9.b. - Page 41
F. Remedies not exclusive. The remedies identified in this Chapter are in addition to and do not
supersede or limit any other remedies, including administrative, civil and/or criminal remedies
pursuant to federal, state, and local law. The remedies provided in this Chapter shall be
cumulative and not exclusive.
13.24.170 Hazards
A. General. No person shall cause or allow the persistence of a condition on any site that could
cause accelerated erosion. Accelerated erosion shall be controlled and/or prevented by the
responsible person or the property owner by using practices outlined hereinafter as applicable.
Additional measures may be necessary, and may be specifically-required by the building official
when work is on geological unstable areas, thirty (30) percent or steeper slopes, and/or on soils
with a severe erosion hazard rating by a USDA Soil Survey. Soil sterilants that last longer than
four weeks shall not be used on soils or slopes which may subsequently need vegetation for
erosion and sediment control. Where feasible, erosion hazard problems shall be controlled no
later than the beginning of the next winter or adverse season.
B. Hazardous Conditions. Whenever the Director of Community Development determines that any
existing excavation or embankment or cut or fill on private property has become a hazard to life
and limb, or endangers property, or adversely affects the safety, use or stability of a public way,
drainage channel or causes significant impact on the natural resources of the area, the owner of
the property upon which the excavation, cut or fill is located, or other person or agent in control of
the property, upon receipt of notice in writing from the Director of Community Development shall,
within the period specified therein, repair or eliminate such hazard and conform with the
requirements of this chapter.
C. No permits of any kind shall be issued if the Director of Community Development determines that
proposed construction work is hazardous to the extent described above, or the work is subject to
a major flood hazard dangerous to life or property, and which hazard cannot be eliminated,
prevented, or corrected.
13.24.180 Fees
Fees for grading permits and grading, drainage, and erosion and sedimentation control plan checking
shall be as set forth in the fee ordinance adopted by the City Council. In compliance with the adopted fee
schedule, the Director of Community Development may require payment of actual recorded costs, plus
overhead, for those applications which will exceed City fees for processing, plan checking, administration,
and/or inspection.
13.24.190 Bonds and securities.
The Director of Community Development may require bonds in such form and amounts"' as may be
deemed necessary to assure that the work, if not completed in accordance with the approved plans and
specifications, will be corrected to eliminate hazardous conditions.
In lieu of a surety bond the applicant may file a cash bond or instrument of credit with the Director of
Community Development in an amount equal to that which would be required in the surety bond.
The surety bond, or in lieu thereof, less the costs of remedial work, if any, shall be released when the
Director of Community Development determines that the best management practices for erosion and
sediment control practices have permanently stabilized the site, but not later than eighteen (18) months
after installation of all permanent erosion control practices.
Item 9.b. - Page 42
EXHIBIT B
Chapter 13.25 ILLEGAL DISCHARGES AND ILLICIT CONNECTIONS
13.25.010 Purpose.
The regulations included in this Chapter are to provide for the health, safety, and
general welfare of the environment and the citizens of the City of Arroyo Grande
through the regulation of non-storm water discharges to the storm drainage system
and receiving waters within the City to the maximum extent practicable as required by
federal and state law.
13.25.020 Applicability.
This Chapter is applicable to all water entering the storm drain system generated on any
developed and undeveloped lands unless explicitly exempted by the State Water
Resource Control Board or the City.
The requirements of this Chapter are not intended to modify or repeal any other
ordinance, rule, regulation, or other provision of law. The requirements of this Chapter
are in addition to the requirements of any other ordinance, rule, regulation, or other
provision of law, and where any provision of this Chapter imposes restrictions different
from those imposed by any other ordinance, rule, regulation, or other provision of law,
whichever provision is more restrictive or imposes higher protective standards for
human health or the environment shall control.
13.25.030 Objectives.
The objectives of this Chapter are:
A. To regulate the contribution of pollutants to groundwater and surface waters
including but not limited to; Arroyo Grande Creek, Tally Ho Creek, Los Berros
Creek or Meadow Creek by storm water discharges.
B. To prohibit illicit connections and illegal discharges to the storm drain system.
C. To establish legal authority to carry out all inspection, surveillance, monitoring,
and enforcement procedures necessary to ensure compliance with this Chapter.
13.25.040 Definitions.
For the purpose of this Chapter, certain words and phrases are defined as follows, and
certain provisions shall be construed as herein set forth, unless it shall be apparent
from the context that they have a different meaning.
A. "Basin Plan" refers to the Central Coast Regional Water Quality Control Board
adopted Water Quality Control Plan, Central Coast Basin that designates
Item 9.b. - Page 43
Ordinance No. 14-_ -Exhibit B
Page 2
beneficial uses, establishes water quality objectives, and contains implementation
programs and policies to achieve those objectives for receiving waters within the
Region.
B. "California Toxics Rule" refers to regulations codified in 40 CFR Section 131.36
and Section 131.38 respectively, which establish numeric criteria for priority toxic
pollutants for California's inland surface waters, enclosed bays, and estuaries.
C. "Incidental runoff' shall mean the unintended amount of runoff, which escapes
the areas of intended use (e.g., minimal over-spray from sprinklers). Water
leaving an intended use area is not considered incidental if it is a result of:
(1) inaaequate or improper facility design;
(2) excessive application;
(3) intentional overflow or application; or
(4) negligence.
D. "Illegal discharge" shall mean any direct or indirect non-storm water discharge to
the storm drain system including discharges from commercial and non-profit car
washes, mobile cleaning services, pressure washing operations and non-storm
water runoff from irrigated areas that is not considered incidental runoff except
as exempted in Section 13.25.060. Illegal discharges are also any discharge that
may cause or threaten to cause or contributes to an exceedance of any water
quality standard in a Statewide Water Quality Control Plan, the California Toxics
Rule, or the Basin Plan.
E. "Storm drain system" shall mean the system of conveyances (including
sidewalks, roads with drainage systems, municipal streets, catch basins, curbs,
gutters, ditches, man-made channels, or storm drains) designed or used for
collecting or conveying storm water, and that is not used for collecting or
conveying sewage.
F. "Non-storm water discharge" shall mean any discharge to the storm drain
system that is not composed entirely of storm water.
G. "Person" shall mean any individual, association, organization, partnership, firm,
corporation or other entity living, working or visiting the City.
H. "Statewide Water Quality Control Plan" refers to documents issued at the State
level for the conservation, development, and utilization of the water resources of
the State. They currently consist of the Oceans Plan, Bay-Delta Plan, Thermal
Plan, and Freshwater and Estuarine Plan, with future plans under development
for Nutrients for Inland Surface Water of the State, and Trash Controls in
California Waters (partial list).
13.25.050 Authority.
The Public Works Director shall have the authority, to detect and eliminate illegal
discharges and illicit connections to the storm drain system. This includes entering onto
private property for the purpose of inspecting, at reasonable times, any facility,
equipment, practices, or operations for compliance with this Chapter.
Should the Public Works Director suspect that an illegal discharge or illicit connection is
present, the Public Works Director may do any or all of the following:
Item 9.b. - Page 44
Ordinance No. 14-_ -Exhibit B
Page 3
A. . For non-storm water discharges suspected of being sanitary sewage and/or
significantly contaminated, require the discharger to promptly cease and desist
discharging and/or cleanup and abate their discharge, spill, or pollutant release
as soon as possible.
B. For suspected illicit connections, require the owner, within 72 hours of
notification, to identify the nature of the suspected illicit connection and to
identify the outfall location or point of connection to the storm drain system,
sanitary sewer system or other discharge point. Should the suspected illicit
connection be confirmed, see item (C) below.
C. For illegal discharges and illicit connections, require the discharger to promptly
cease and desist discharging and/or cleanup and abate their discharge, spill, or
pollutant release within 72 hours of notification.
D. For incidental runoff, require the person responsible to detect leaks and correct
the leaks within 72 hours of learning of the le~ks, and remedy other situations
within 10 days, which may include properly designing and aiming sprinkler
heads, and/or not irrigating during precipitation events.
13.25.060 Prohibition of Illegal Discharges.
No person shall throw, drain, or otherwise discharge, cause, or allow others under its
control to throw, drain, or otherwise discharge into the storm drain system or to
groundwater and surface waters, including but not limited to; Arroyo Grande Creek,
Tally Ho Creek, Los Berros Creek or Meadow Creek, any material other than storm
water, except as allowed by this Chapter or as otherwise authorized by a separate
NPDES Permit, waiver, or waste discharge order issued to the discharger and
administered under the authority of the United States Environmental Protection Agency
(EPA), provided that the discharger is in full compliance with all requirements of the
permit, waiver, or order and other applicable laws and regulations, and provided that
written approval has been granted for any discharge to the storm drain system.
The following non-storm water discharges may be allowed provided appropriate control
measures to minimize the impacts of such discharges are consistent with the California
Stormwater Quality Association (CASQA) Best Management Practices Handbook, or
equivalent precautions are taken:
(A) water line flushing;
(8) individual residential car washing;
(C) diverted stream flows;
(D) rising ground waters;
(E) uncontaminated ground water infiltration (as defined at 40 C.F. R. §35.2005(20))
to separate storm sewers;
(F) uncontaminated pumped ground water;
(G) discharges from potable water sources;
(H) foundation drains;
(I) air conditioning condensation;
(J) springs;
Item 9.b. - Page 45
Ordinance No. 14-_ -Exhibit B
Page4
(K) water from crawl space pumps;
(L) footing drains;
(M) flows from riparian habitats and wetlands;
(N) de-chlorinated swimming pool discharges;
(0) incidental runoff from landscaped areas;
(P) discharges or flow from firefighting; and
(Q) other discharges approved by the Public Works Director and specified in writing
as being necessary to protect public health and safety.
This provision does not obviate the need to obtain any other appropriate permits, such
as discharges which are required to be enrolled under Order R3-2011-0223 'Waste
Discharge Requirements National Pollution Discharge Elimination System (NPDES)
General Permit for Discharges with Low Threat to Water Quality."
13.25.070 Prohibition of Illegal Connections.
The construction, use, maintenance or continued existence of illicit connections to the
storm drain system is prohibited. This prohibition expressly includes, without limitation,
illicit connections made in the past, regardless of whether said drain or connection had
been previously allowed, permitted, or approved by an authorized enforcement agency
or permissible under law or practices applicable or prevailing at the time of connection.
A. Illicit connections include any drain or conveyance, whether on the surface or
subsurface that allows an illegal discharge to enter the storm drain system
including but not limited to, any conveyances that allow any non-storm water
discharge including sewage, processed wastewater, and wash water to enter the
storm drain system, and any connections to the storm drain system from indoor
drains and sinks or, any drain or conveyance connected from a commercial or
industrial land use to the storm drain system that has not been documented in
plans, maps, or equivalent records and approved by an authorized enforcement
agency.
8. Improper connections in violation of this Chapter must be disconnected and
redirected, if necessary, to an approved onsite wastewater management system
or the sanitary sewer system upon approval of the City.
C. Any drain or conveyance that has not been documented in plans, maps or
equivalent, and which may be connected to the storm drain system, shall be
located by the owner or occupant of that property upon receipt of written notice of
violation from the City requiring that such locating be completed. Such notice will
speCify a 72 hour time period within which the location of the drain or conveyance
is to be determined, that the drain or conveyance be identified as storm drain,
sanitary sewer or other, and that the outfall location or point of connection to the
storm drain system, sanitary sewer system or other discharge point be identified.
Results of these investigations are to be documented and provided to the Public
Works Director.
Item 9.b. - Page 46
Ordinance No. 14-_ -Exhibit B
Page 5
13.25.080 Violations.
It shall be unlawful for any person to violate any provision or fail to comply with any of
the requirements of this Chapter. Any person who has violated or continues to violate
the provisions of this Chapter, may be subject to the enforcement actions outlined in
this section or may be restrained by injunction or otherwise abated in a manner
provided by law. ·
A. In the event the violation constitutes an immediate danger to public health or
public safety, the City is authorized to enter upon the subject private property,
without giving prior notice, to take any and all measures necessary to abate the
violation and/or restore the property.
B. Warning Notice. When the City finds that any person has violated, or continues to
violate, any provision of this Chapter, or any order issued hereunder, the City
may serve upon that person. a written Warning Notice, specifying the particular
violation believed to have occurred and requesting the discharger to immediately
investigate the matter and to seek a resolution whereby any offending discharge
will cease. Investigation and/or resolution of the matter in response to the
Warning Notice in no way relieve the alleged violator of liability for any violations
occurring before or after receipt of the Warning Notice. Nothing in this subsection
shall limit the authority of the City to take any action, including emergency action
or any other enforcement action, without first issuing a Warning Notice.
C. . Notice of Violation. Whenever the City finds that a person has violated a
prohibition or failed to meet a requirement of this Chapter, the City may order
compliance by written Notice of Violation to the responsible person. The Notice of
Violation shall contain:
(1) The name and address of the alleged violator;
(2) The address when available or a description of the building, structure or land
upon which the violation is occurring, or has occurred;
(3) A statement specifying the nature of the violation;
(4) A description of the remedial measures necessary to restore compliance with
this Chapter and a time schedule for the completion of such remedial action;
(5) A statement of the penalty or penalties that shall or may be assessed against
the person to whom the notice of violation is .directed;
(6) A statement that the determination of violation may be appealed to the City
Public Works Director by filing a written notice of appeal within 10 days of
service of notice of violation; and
(7) A statement specifying that, should the violator fail to restore compliance
within the established time schedule, the work will be done by a designated
governmental . agency or a contractor and the expense thereof shall be
charged to the violator.
Item 9.b. - Page 47
Ordinance No. 14-_ -Exhibit B
Page 6
Such notice may require without limitation:
(1) The performance of monitoring, analyses, and reporting;
(2) The elimination of illicit connections or discharges;
(3) That violating discharges, practices, or operations shall cease and desist;
(4) The abatement or remediation of storm water pollution or contamination
hazards and the restoration of any affected property;
(5) Payment of restitution to cover all administrative, labor and remediation costs
incurred by the City; and
(6) The implementation of source control or treatment BMPs consistent with the
California Storm Water Quality Association (CASQA) Best Management
Practices Handbooks or equivalent.
D. Penalties. In the event the alleged violator fails to take the remedial measures set
forth in the notice of violation or otherwise fails to cure the violations described
therein, the alleged violator is subject to civil and/or criminal action in accordance
with Chapter 1.16 of this Code.
E. Compensatory Action. In lieu of enforcement proceedings, penalties, and
remedies authorized by this Chapter, the City may impose upon a violator,
alternative compensatory options, such as storm drain stenciling, attendance at
compliance workshops, creek cleanup, etc.
Item 9.b. - Page 48
Exhibit C
City of Arroyo Grande
Design Requirements for
Post Construction Stormwater Compliance
Purpose
The purpose of this document is to provide guidance and direction on how to comply with Post-
Construction Stormwater Requirements (PCR's) within the City of Arroyo Grande. This document is
intended to be used by developers, contractors, builders, designers, engineers, architects, planners,
homeowners, and all others interested in learning how to address stormwater quality during the planning,
design, construction and maintenance phases of a project. It is meant to be used as an aid for both onsite
and public improvement projects.
Project applicants should use this document to:
• Determine which performance requirement apply
• Understand how each performance requirement will be applied within the City
• Obtain direction regarding means of demonstrating compliance
Impact of Development on Water Resources
Undeveloped natural landscape areas such as forests and grasslands act like sponges for rainfall. When
natural landscape areas are covered with impervious (nonporous) surfaces like roads, parking lots, and
roofs, this "sponge-like" function is lost and the amount of rainfall that can be absorbed is considerably
reduced. The percentage of impervious surface area of a site influences how much stormwater is
infiltrated into the ground, evapotranspirated back into the atmosphere, or leaves the site as stormwater
runoff. See figure 1.
When the amount of impervious surface area of a site is altered the normal watershed processes is also
altered. This can lead to a significant host of problems including:
• Increased loads of chemical pollutants;
• Increased toxicity;
• Changes to flow magnitude, frequency, and seasonality of various discharges;
• Physical changes to stream, lake, or wetland habitats;
• Changes in the energy dynamics of food webs, sunlight, and temperature;
• Changes in biotic interactions between native and exotic species.
Changes in impervious surface area can also alter the amount and quality of stormwater that infiltrates
and recharges our groundwater aquifers.
Item 9.b. - Page 49
25% shallow
infiltration
40% evapotranspiration
10%
runoff
25% deep
infiltration
21% shallow
infiltration
38% evapotranspiration
_,,/·--~--
20%
runoff
/
21% deep
infiltration
Natural Ground Cover 10%·20% Impervious Surface
35% evapotranspiration 30% evapotranspiration
20% shallow
infiltration
/"'•.
/ ' _,______ ~-·
30%
runoff
15% deep
infiltration
--:•••• ••••• ••••• •••• •••• ........ 1••··· '••··· ••••• ,::••• : .. :·· • •
10% shallow
infiltration
-·
35%·50% Impervious Surface 75%·100% Impervious Surface
Figure 1. The relationship between impervious surface area, runoff,
infiltration and evapotranspiration.
(Stream Corridor Restoration: Principles, Processes, & Practices, FISWG 1998)
5% deep
infiltration
The loss of infiltration from urbanization has also resulted in significant groundwater changes. As more
surface area becomes covered with impervious surfaces, less water is able to seep back into the ground.
Reduced groundwater recharge rates may result in lower base flows during dry weather as less
groundwater is available to move through the soil and into stream channels and aquifers. See Chapter
13.05 of the City's Municipal Code for more on City's regulations regarding Water Conservation.
To protect surface water quality and groundwater resources, new development and significant
redevelopment projects should be designed, constructed, and maintained to minimize the interruption of
natural watershed processes and to treat storm water as a resource and an asset, instead of a waste
product.
Item 9.b. - Page 50
Post Construction Requirements
The Central Coast Regional Water Quality Control Board recognizes that it is necessary to protect
watershed processes so that beneficial uses of receiving waters are maintained and, were applicable,
restored. The primary objective of these Post-Construction Stormwater Management Requirements is to
ensure reduction of pollutant discharges to the Maximum Extent Practicable and preventing stormwater
discharges from causing or contribution to a violation of receiving water quality standards in all
applicable development projects that require approvals and/or permit is issued under the planning,
building or other comparable authority. To address the impacts of development on water quality, the
National Pollutant Discharge Elimination System (NPDES) Small Municipal Separate Storm Sewer
System (MS4) General Permit requires the City of Arroyo Grande to develop and implement a Guidance
Document that includes specific Best Management Practices (BMPs).
Figure 3-2. Which Performnnce ReQuirements Apply?
YES
Table 3-1
•-. ~ • YES
-Cmnplllt11ty drains tD 1n an !:ite uodrairmd d•pressicn
II Projact ;s lacatad autsidl!ll af County
MS4 Pl:rmrt Ar111 ta• App A)
Teble 3-2
-Road aad p11rlring 101 maintenanco
I Su!a...O: e:sd b1cyclli lane pr1JJ8Cts lwwban11 na atn.1
i:mperviom surfaces ani geatad er .-.,ptaadl. and
built ta lir•c.t :sumnwawr 10 ••c.m ngmtatad .,. ..
II Trmls 11nd pathway5 1Wher11 na attw:r imparrious
aurfm:cl erw crwot9d or r•plllmdl. and buth to direct
StormWlllU runoff to adjamnt wg111taid arHs
II Undlrgroood utd11y ptojat:t3. that nplace lb• ground
swfsr:o with in-kind matarial or mam::risl.s with
s:milar runoff ch.lrecte•ISllCSI
I Curb and gumr improvmnant or repjemmen1
pra:J8CU' itau ani not put of the ·~v addstaana1
cniation or repbu:mnam of imptA'IOUS" curfam anaa
(e.g. sidawai.11.s. 1aadwayl
•
Slcond story additJGm: that do not fnereas11 the
budding fmuprinl
RIR38d tnot bwa ctnactJy an 1h11 ground! dlldr.s.
snirs,. cu W\. .. lkways dm:sfgned With SOllCSS to •llow
for wat9t' dr11inao11
PborDYoli.it systams insuDad anJonr a:isttng rao1
or other imp111vio~ awface:s, end panals locauid
over P9•wia1.tS aml•C8:S with w.tkn•1no1nad gress or
veg•taled CDftlf, or penal arnsva Wth e buffer atrip
•• Iha nm.st ct-'I grRdmnr-nwu of pmrm'9
Tempor•ry srructura {la place for lea than si•
months)
•
Ehn:tricel and 1.1tility •alv•s, SIW&r end watar lilt
stetiom, bad:ffovus and othlr utihty dav1cas
•
Abowa-groimd ltml stM•Oll lanks mad l•I lanns with
cDRl'*nmmll systarn:s
, , -----
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Do•• project creab 1 ........ -..
YES
~
<:0 '.L_ < 5.000 st DI net
imperviDWl arua7 t" ---YES .YES~ ( D :"'5.lllJD•latnet
, t_ Dan pnsjaet creato ...............
~ 1mpm1n0m1 ..... 1 ---.----(.fUD) ......
no-prajact create .............
< 16.000 .. ot ... .
impenrioas .... 1 I
If·~ ···~-· olwp
-=----'
/--_ __/
.-.. '-'· .wo·:
-r
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~
'
' _,-~Does!:-·· .( D < 22.6DD d at aow
YES"_. . •ad ia:zpsryious · l sartacel
JI.. .
r PR,_.,,~ ___ /
j PR#2
PR.#3 [~ ___ ·_,,~
PR-#4
PR.rs
l
'
• See Appendbt D If site unable to retain
requiFod PR3 Volumes
Figure 2. Performance Requirement Flow Chart
(Source: County of San Luis Obispo)
Item 9.b. - Page 51
Regulated projects include all new development or redevelopment projects that create and/or replace
greater than or equal to 2,500 square feet of impervious surface (collectively over the entire project site).
Using the flow chart Figure 2, determine ifthe project is:
• EXEMPTor
• SUBJECT TO ONE OR MORE PERFORMANCE REQURIEMENT (i.e. the project is
regulated),
The project is exempt if the project retains 100% of stormwater on site for all storms or if the project
consist of only one of the items listed in Draft Resolution No. R3-2013-0032, Section B. Post -
Construction Requirements I b. Typically, maintenance and utility projects are also considered "exempt"
from post-construction requirements specified by the Regional Board. Examples of exempt maintenance
projects include routine overlays and slurry seals. Examples of utility projects that are "exempt" include
the installation of an ADA ramps, or solar panels on rooftops, or repair of roads or aerial utilities.
If the project meets the criteria to be considered "Exempt", project applicants are still encouraged to
implement practices that will reduce stormwater impacts associated with their proposed development.
Performance Requirements
If the project is considered to be a Regulated project, the regulated project will be required to meet
Performance Requirement 1 (PR 1 ). Many regulated projects are required to meet additional performance
requirements. To determine if the project must meet additional requirements, you must determine the Net
Impervious Area.
The Net Impervious Area is the total (including new and replaced) post-construction impervious areas,
minus any reduction in total imperviousness from the pre-project to post-project conditions. Permeable
pavements may only be excluded from the impervious surface area calculation if they are designed to
infiltrate.
Net
impervious
area
New and replaced
impervious area
Pre-project to post-project
reduction in impervious area, if
any
Pre-project impervious areas consists of all hard, non-vegetated surface area that prevents or
significantly limits the entry of water into the soil mantle, as would occur under natural conditions prior
to development. Common impervious surfaces include, but are not limited to, roof tops, walkways, patios,
driveways, parking lots or storage areas, concrete or asphalt paving, surfaces which impede the natural
infiltration of stormwater. Open, uncovered retention/detention facilities shall not be considered as
impervious surfaces for purposes of determining whether the thresholds for application of Performance
Requirements are exceeded. However, for modeling purposes, open, uncovered facilities that retain/detain
water (e.g., retention ponds, pools) shall be considered impervious surfaces.
Item 9.b. - Page 52
Total Project Site Area is the area defined by the legal boundaries of a parcel or parcels of land which
the new development or redevelopment takes place.
Post-project Impervious surface areas is the total (including new and replaced) impervious areas on the
development site once the project is completely constructed. They include, but are not limited to: roof
tops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, surfaces
which impede the natural infiltration of stormwater. It does not include open, uncovered
retention/detention facilities.
New (%) is the portion of the post-project impervious area that did replace an existing pervious surface
area.
Replaced (%) is the portion of the post-project impervious area that replaced an existing impervious
surface area.
Total Disturbed Area is the portion of the total project site area that will be subject to construction, used
as a staging or storage area, or whose vegetation and soils are otherwise directly impacted by the project.
An applicant will be required to provide supporting documentation regarding permeable paver (or
alternate surface) areas excluded from impervious area calculations.
The five Post-Construction Requirements (PCRs) developed by the State Regional Water Quality Control
Board are summarized below:
Performance Requirement 1: Site Design and Runoff Reduction
All regulated projects, projects creating and/or replace 2: 2,500 square feet of impervious surface
(collectively over the entire project site), including detached single-family home projects, are subject to
PR 1 and must minimally incorporate the following Low Impact Development (LID) design strategies
into the project.
1. Limit disturbance of creeks and natural drainage features
2. Minimize compaction of highly permeable soils
3. Limit clearing and grading of native vegetation at the site to the minimum area needed to build
the project, allow access, and provide fire protection
4. Minimize impervious surfaces by concentrating improvements on the least sensitive portions of
the site, while leaving the remaining land in a natural undisturbed state
5. Minimize stormwater runoff by implementing one or more of the following site design measures:
i. Direct roof runoff into cisterns or rain barrels for reuse
11. Direct roof runoff onto vegetated areas safely away from building foundations and
footings, consistent with California building code
m. Direct runoff from sidewalks, walkways, and/or patios onto vegetated areas safely
away from building foundations and footings, consistent with California building
code
Item 9.b. - Page 53
iv. Direct runoff from driveways and/or uncovered parking lots onto vegetated areas
safely away from building foundations and footings, consistent with California
building code
v. Construct bike lanes, driveways, uncovered parking lots, sidewalks, walkways, and
patios with permeable surfaces
The developer shall provide appropriate documentation certifying that project complies with
Site Design and Runoff Reduction Performance Requirements. Certification Statement shall
clearly identify the level of compliance with each of the applicable performance requirements the
project is subject to. All certification shall be signed and stamped by the engineer of Record and shall
include qualify and quantify identified deficiencies, per performance requirements.
Performance Requirement 2: Water Quality Treatment
Projects subject to PR2 are projects with a Net Impervious Area 2: 5,000 square feet, that are not single
family homes, and detached single family homes 2:15,000 square feet of Net Impervious Area. These
projects shall treat stormwater runoff to reduce pollutant loads and concentrations using physical,
biological and chemical removal. Developer shall provide and include net impervious area calculations.
Regulated projects subject to PR2 must treat a defined minimum volume or maximum surface loading
rate of runoff using onsite measures. Allowable onsite measures are listed in the order of preference
(highest to lowest):
• Low Impact Development -implement harvesting and use infiltration, and evapotranspiration
measures that collectively retain stormwater runoff equal to the volume of runoff generated by
the 85th percentile 24-hour storm event, based on local rainfall data.
• Biofiltration Treatment Systems -implement biofiltration systems using facilities that must be
demonstrated to be at least as effective as a biofiltration treatment system that meets the
following parameters:
i. a max surface loading rate of 5" per hour based on a rain intensity of 0.2 inches or two
times the 85th percentile hourly rainfall intensity for the applicable area,
ii. Surface minimum reservoir volume of equal to the biofiltration area times a depth of 6
inches,
m. Proper plan selection with a minimum depth of 24 inches and an infiltration rate of 5
in/hr,
iv. Subsurface drain/storage layer with an area equal to the biofitration surface area and
having a minimum depth of 12 inches.
• Non-Retention Based Treatment Systems -implement stormwater control measure that achieve
at least one of the following:
1. a volume capacity designed to treat stormwater runoff equal to the runoff generated by
the 85th percentile 24-hour storm event
ii. a flow capacity sized equal to at least two times the 85th percentile hourly rainfall
intensity for the applicable area and equal to at least 0.2 in/hr intensity.
Item 9.b. - Page 54
Design alternatives will only be considered if the applicant can demonstrate that ALL of the following
measures of equivalent effectiveness are demonstrated:
1. Equal or greater amount of runoff infiltrated or evapotranspired;
2. Equal or lower pollutant concentrations in runoff that is discharged after bio-filtration;
3. Equal or greater protection against shock loadings and spills; and
4. Equal or greater accessibility and ease of inspection and maintenance.
Technical guidance for designing bio-retention facilities is available from the Central Coast LID Initiative
web site:
http:ljwww.centralcoastlidi.org/Central Coast LIDl/LID Structural BMPs.html
The guidance includes design specifications and standard plans. It also includes plant lists appropriate for
installation of LID and Bio-filtration Systems on the Central Coast.
Project subject to PR2 shall include a Stormwater Control Plan (SWCP) containing the following:
1. Project type and address and name of applicant
2. Calculations for total new, replaced and net impervious area pre/post development
3. Applicable requirement for both PR 1 and PR 2
4. Description of all post construction structural stormwater control measures including calculations
5. Documentation certifying that the selection, sizing and design of measures meet requirements
Performance Requirement 3: Runoff Retention
Performance Requirement 3 shall apply to projects, except detached single family homes, that create
and/or replace~ 15,000 square feet of impervious surface (collectively over the entire project site), and
detached single family homes~ 15,000 square feet of net impervious area, WMZs 1, 2.
Regulated projects subject to PR3 must retain a designated design storm volume. Applicants of regulated
projects subject to this requirement must:
1. Watershed Management Zone 1:
a) Retain 95th Percentile Rainfall Event -Prevent offsite discharge from events up to the 95th
percentile 24-hour rainfall event as determined from local rainfall data.4
b) Compliance must be achieved via infiltration
2. Watershed Management Zone 2:
Item 9.b. - Page 55
a) Retain 95th Percentile Rainfall Event -Prevent offsite discharge from events up to the 95th
percentile 24-hour rainfall event as determined from local rainfall data.
b) Compliance must be achieved via storage, rainwater harvesting, infiltration, and/or
evapotranspiration.
PR3 regulated projects shall use the following LID development standards:
1. Site Assessment Measures -each Regulated Project shall identify opportunities and constraints
to implement LID Stormwater Control Measures. Provide documentation of the following, as
appropriate to the development site:
a) Site topography including hydrologic features
b) Seasonal high groundwater
c) Geological analysis including geotechnical hazards
d) Soil type and hydrologic soil groups
e) Run-on characteristics and existing drainage infrastructure
2. Site Design Measures -Regulated Project shall optimize the use of LID site design measures, as
feasible and appropriate at the project site. Regulated Projects subject to Performance
Requirement No. 3 must augment design strategies required by Performance Requirement No. 1
with the following:
a) Define the development envelope and protected areas, identifying areas that are most
suitable for development and areas to be left undisturbed
b) Conserve natural areas, including existing trees, other vegetation, and soils
c) Limit the overall impervious footprint of the project
d) Construct streets, sidewalks, or parking lot aisles to the minimum widths necessary,
provided that public safety or mobility uses are not compromised
e) Set back development from creeks, wetlands, and riparian habitats
f) Conform the site layout along natural landforms
g) A void excessive grading and disturbance of vegetation and soils
3. Delineation of discrete Drainage Management Areas (DMAs) -Regulated Project shall
delineate DMAs to support a decentralized approach to stormwater management. A map or
diagram dividing the entire project site into discrete DMAs shall be provided.
Each Regulated Project shall account for the drainage from each DMA using measures identified
as follows:
Item 9.b. - Page 56
a) Undisturbed and Natural Landscape Areas -each Regulated Project shall implement
appropriate Site Design and Runoff Reduction Measures in Performance Requirement
No. 1, to reduce the amount of runoff for which retention and treatment is required.
Runoff reduction measures that can be used to account for this reduction also include as
follows:
i. Undisturbed or areas planted with native, drought-tolerant, or LID appropriate
vegetation that do not receive runoff from other areas may be considered self-treating
and no additional stormwater management is required.
11. Runoff from impervious surfaces, generated by the rainfall events identified in
Section B.4.c, may be directed to undisturbed or natural landscaped areas. When the
applicant can demonstrate that this runoff will be infiltrated and will not produce
runoff to the storm drain system, or a surface receiving waterbody, or create nuisance
ponding that may affect vegetation health or contribute to vector problems, then no
additional stormwater management is required for these impervious surfaces.
b) Structural Stormwater Control Measures -Where it has been demonstrated m the
Stormwater Control Plans, that the use of Site Design measures listed above, Runoff
Reduction measures listed in Performance Requirement No. I, and undisturbed and
natural landscape has been maximized to the extent feasible, Structural Stormwater
Control Measures designed for water quality treatment and/or flow control shall be used
to comply with Performance Requirement No. 3.
4. Ten Percent Adjustment for Sites with Technical Infeasibility -Where technical infeasibility, as
described in Section C.1.c., prevents full on-site compliance with the Runoff Retention
Performance Requirement, on-site retention of the full Retention Volume per Section B.4.d.vi. is
not required and the Regulated Project is required to dedicate no less than ten percent of the
Regulated Project's Equivalent Impervious Surface Area5 to retention-based Stormwater Control
Measures.
5. Off-Site Mitigation -Off-site mitigation is required when Regulated Projects do not retain the
full Retention Volume, and 1) fail to demonstrate technical infeasibility of full retention; or 2)
demonstrate technical infeasibility of full retention AND fail to dedicate at least ten percent of the
Regulated Project's Equivalent Impervious Surface Area to retention-based Stormwater Control
Measures.
6. Reporting Requirements -For each Regulated Project subject to the Runoff Retention
Performance Requirement, provide the following information in a Stormwater Control Plan. Final
project approval shall not be granted until the Stormwater Control Plan for the Regulated Project
sufficiently demonstrates the Regulated Project design meets the Water Quality Treatment and
Runoff Retention Performance Requirements.
Performance Requirement 4: Peak Management
All Regulated Projects that create and/or replace >22,500 square feet of impervious surface (collectively
over the entire project site) in Watershed Management Zones 1 and 2 shall manage peak stormwater
runoff to ensure that post-development peak flows, discharged from the site, do not exceed pre-project
peak flows for the 2-through 10-year storm events and shall meet Water Quality Treatment and Runoff
Item 9.b. - Page 57
Retention Performance Requirements.
Reporting Requirements -For each Regulated Project subject to the Peak Management Performance
Requirement a Stormwater Control Plan shall be required. Final project approval shall not be granted until
the Stormwater Control Plan for the Regulated Project sufficiently demonstrates the Regulated Project
design meets the Water Quality Treatment, Runoff Retention, and Peak Management Requirements.
Performance Requirement S:Special Circumstances
There are no Special Circumstances designation in the City of Arroyo Grande.
Alternative Compliance
The City will only consider alternative compliance for projects able to demonstration technical
infeasibility and who cannot satisfy the I 0% adjustment criteria on site. Alternative Compliance may be
allowed under the following circumstances:
I. Technical Infeasibility -applicant must submit a site-specific hydrologic and/or design analysis
conducted and endorsed by a registered professional engineer, geologist, architect, and/or
landscape architect, demonstrating that compliance with the applicable numeric Post-
Construction Stormwater Management Requirements is technically infeasible.
2. The Regulated Project applicant must submit a description of the project(s) that will provide off-
site mitigation. The proposed off-site projects may be existing facilities and/or prospective
projects that are as effective in maintaining watershed processes as implementation of the
applicable Post-Construction Stormwater Requirements on-site.
The description shall include:
c) The location of the proposed off-site project(s) must be within the same watershed as the
Regulated Project. Alternative Compliance project sites located outside the watershed
may be approved by the Central Coast Water Board Executive Officer
d) A schedule for completion of offsite mitigation project(s), where the off-site mitigation
project(s) has not been constructed.
Technical infeasibility may be caused by site conditions, including:
a) Depth to seasonal high groundwater limits infiltration and/or prevents construction of sub-
grade stormwater control measures
b) Depth to an impervious layer such as bedrock limits infiltration
c) Sites where soil types significantly limit infiltration
d) Sites where pollutant mobilization in the soil or groundwater is a documented concern
e) Space constraints (e.g., infill projects, some redevelopment projects, high density
development)
Item 9.b. - Page 58
•.
f) Geotechnical hazards
g) Stormwater Control Measures located within 100 feet of a groundwater well used for
drinking water
h) Incompatibility with surrounding drainage system (e.g., project drains to an existing
stormwater collection system whose elevation or location precludes connection to a properly
functioning treatment or flow control facility).
Operational and Maintenance Plans
The developer shall submit an Operation and Maintenance Plan and Maintenance Agreements (O&M
Plan) that clearly establish responsibility for all structural Water Quality Treatment, Runoff Retention,
and/or Peak Management controls for all Regulated Projects.
The Regulated Project applicant shall develop and implement a written O&M Plan. The O&M Plan shall
be submitted for approval prior to final approval/occupancy. The O&M Plan must include:
a. A site map identifying all structural Stormwater Control Measures (SCM's) requiring O&M
practices to function as designed
b. O&M procedures for each structural stormwater control measure including, but not limited to,
LID facilities, retention/detention basins, and proprietorship devices.
c. The O&M Plan will include short-and long-term maintenance requirements, recommended
frequency of maintenance, and estimated cost for maintenance.
Maintenance Agreement and Transfer of Responsibility for SCMs: Prior to issuing approval for final
occupancy the owner of the Regulated Project subject to these Post-Construction Requirements shall
provide verification of ongoing maintenance provisions for Structural Stormwater Control Measures,
including but not limited to legal agreements, covenants, CEQA mitigation requirements, and or
conditional use permits. Verification shall include, at a minimum:
a. The project owner's signed statement accepting responsibility for the O&M of the installed onsite
and/or offsite structural treatment and flow control SCMs until such responsibility is legally
transferred to another entity; and either
i. A signed statement from the public entity assuming responsibility for structural treatment
and flow control SCM maintenance and stating that the SCM meets all local agency
design standards; or
n. Written conditions in the sales or lease agreements or deed for the project that require the
buyer or lessee to assume responsibility for the O&M of the onsite and/or offsite
structural treatment and flow control SCM until such responsibility is legally transferred
to another entity; or
111. Written text in project deeds, or conditions, covenants and restrictions for multi-unit
.residential projects that require the homeowners association or, if there is no association,
each individual owner to assume responsibility for the O&M of the onsite and/or offsite
Item 9.b. - Page 59
structural treatment and flow control SCM until such responsibility is legally transferred
to another entity; or
iv. Any other legally enforceable agreement or mechanism, such as recordation in the
property deed, that assigns responsibility for the O&M of the onsite and/or offsite
structural treatment and flow control SCM to the project owner(s).
Reporting
The Central Coast Regional Board requires two types of reporting.
• Project applicant reporting to the City
Applicants of regulated projects subject to Runoff Retention Requirement (PR 3) are
required to demonstrate compliance with a decentralized. approach to stormwater
management through a Stormwater Control Plan. Additional supporting information is
required if the project is subject to additional Performance Requirements.
Determine Watershed Management Zones
Projects creating or replacing 15,000 square feet or more of impervious surfaces, that are not a detached
single family residence, and do not qualify for a special circumstance designation, will need to know their
Watershed Management Zone (WMZ). Watershed management zones (WMZs) are based on common key
watershed processes and receiving water type. They are the basis for determining if the project is subject
to Runoff Retention Performance Standards, or Runoff Retention and Peak management Requirements
Performance Standards. There are two Watershed Management Zones located within the City of Arroyo
Grande. For a copy of the Watershed Management Zone map please visit the Engineer's office at City
Hall. If the project is located on one or the two WMZs, the applicant shall satisfy the requirements of each
zone proportionately. The City's Engineering Division can assist if the maps does not clearly identify the
watershed management zone the project is located in.
Determine Applicable Rainfall Event
The performance criteria for post-construction retention standards is the percentile storm that best
represents the volume that is fully infiltrated in a natural condition, and thus should be managed onsite to
maintain the pre-development hydrology for duration, rate and volume of stormwater flows. The
percentile rain event is the 95th percentile rain event and shall be achieved by infiltration, rainwater
harvesting and/or evaporation for Watershed Management Zones 1 and 2. To obtain exhibits for the 85th
and 95th percentile, 24-hour storm exhibits go to
http://www.swrcb.ca.gov/rwqcb3 /water issues/programs/stormwater /docs/lid/lid hydromod c
harette index.shtml
Item 9.b. - Page 60
Stormwater Control Plan (SWCP) Coversheet
Owner/Engineer contact inform (as applicable)
Name: _______________________________ _
Mailing Address:----------------------------
Email Address: Phone number: ------------------------
Permit/Project Number: ______ _ Property APN: _________ _
Impervious surface values:
Pre-Project: Post-Project:
Impervious Area (sf): ImperviousSurfaceArea(sf):
New(%):
Total Project Site Area (ac): Replaced(%):
Net Impervious Area (sf):
Total Disturbed Area (ac):
Applicable Performance Requirements
o Performance Requirement 1: Site Design and Runoff Reduction
o Performance Requirement 2: Water Quality Treatment
o Performance Requirement 3: Runoff Retention
o Performance Requirement 4: Peak Management
o Performance Requirement 5:Special Circumstances
(select applicable special circumstance(s) from list below)
_Highly Altered Channel
_Intermediate Flow Control Facility
Historic Lake or Wetland
_Technical Infeasibility: Equivalent Impervious Surface Area: _____ _
Identify appropriate certification statement being pursued:
o (Full compliance)
o (Partial compliance on-site)
Location of off-site features:
0 (Alternative Compliance)
-------------------
Certification statement must be seal and signed by a State of California licensed civil engineer.
Item 9.b. - Page 61
Report
Stormwater Control Plan (SWCP) Checklist
o Cover Sheet.
o Table of Contents.
o Project type (commercial, industrial, multiunit residential, mixed use, public) and description.
o Identify if project will be completed in phases, and if so, what phase is represented by the
SWCP.
o List of permits requested and other permits required (401, 404, Caltrans Encroachment, etc).
o Table of Performance Requirements applicable to project and ifthere are any adjustments
required.
o Checklists from each applicable performance requirement or alternate compliance, as
appropriate.
o Site assessment summary (Step 2 and 3). Reference Site Stormwater Assessment Exhibit
described below.
o Summary of Site Design and Runoff Reduction, Water Quality Treatment, Runoff Reduction
and Structural Stormwater Control Measures, by Drainage Management Area, as well as the
entire site (as applicable to project). Reference Exhibits listed below. Identify types of retention
and non-retention based measures specified.
o Supporting calculations to demonstrate compliance with applicable Performance Requirements.
o Statements of Compliance.
Exhibits
o Drainage Management Area (OMA) Exhibit.
o Uniquely identify each OMA and indicate if the OMA is self-retaining (zero discharge),
self-treating, or draining to a treatment/flow control facility.
o Include location of all infiltration, treatment, or flow-control facilities, their tributary
area and basis for sizing (rational C, NRCS CN value, Tc, etc)
o Potential pollutant source areas (if applicable), including loading docks, food service
areas, refuse areas, outdoor processes and storage, vehicle cleaning, repair or
maintenance, fuel dispensing, equipment washing, etc.
o Plan Set with Construction Details for drainage related items (as appropriate)
o Site Stormwater Assessment Exhibit.
o Site map with (existing and proposed) topographic information
o Delineation of sensitive areas, native vegetation and soils types. (Can be provided on
multiple exhibits to supplement design strategy narrative)
Item 9.b. - Page 62
Performance Requirement 1: Site Design and Runoff Reduction SWCP Checklist
DESIGN STRATEGY MEANS OF DEMONSTRATING
COMPLIANCE
1 Limit disturbance of creeks and natural drainage Pre and post drainage feature map.
features. Delineate natural drainage features on Site
Stormwater Assessment Exhibit and OMA
Exhibit, as applicable.
2 Minimize compaction of highly permeable soils. Site Stormwater Assessment Exhibit of soil
types, overlain with development footprint
3 Limit clearing and grading of native vegetation Site Stormwater Assessment Exhibit with
at the site to the minimum area needed to build native vegetation, overlain with development
the project, allow access, and provide fire footprint.
protection.
4 Minimize impervious surfaces by concentrating Site Stormwater Assessment Exhibit with
improvements on the least-sensitive portions of delineated sensitive areas overlain with
the site, while leaving the remaining land in a development footprint
natural undisturbed state.
MINIMIZE STORMWATER RUNOFF BY IMPLEMENTING ONE OR MORE OF THE FOLLOWING DESIGN MEASURES:
MANDATORY SITE DESIGN MEASURES Selected Reason,
(SELECT AT LEAST ONE) for not selecting
a. Roof runoff directed into cisterns or rain
barrels for reuse?
Roof runoff directed into vegetated areas
b. (safely away from building foundations and
footings)?
5 c.
Runoff from sidewalks, walkways, and/or
patios directed onto vegetated areas
(safely away from the building foundations
and footings)?
Runoff from driveways and/or uncovered
d. parking lots onto vegetated areas (safely
away from the building foundations and
footings)?
Are bike lanes, driveways, uncovered
e. parking lots, sidewalks, walkways, and
patios constructed with permeable
surfaces?
NOTE: This checklist must be included with every project application (except for projects deemed
EXEMPT). See Figure xxx to determine if your project is considered exempt, or regulated.
Item 9.b. - Page 63
Performance Requirement 2: Water Quality Treatment SWCP Checklist
o Project Net Impervious Area
o Certification that on-site water quality treatment measures have been met on site, or if not
achievable:
o Documentation of the volume of runoff for which compliance cannot be achieved on site and the
associated off-site compliance requirements;
o Statement of intent to comply with Water Quality Treatment Performance Requirement through
Alternative Compliance.
For each Drainage Management Area, provide:
o Unique DMA Number, area, and likely pollutant(s) of concern
o Water Quality Treatment Approach
N/A if self-treating, or,
Through the use of LID, Biofiltration or Non-retention Based Treatment System);
o Supporting calculations demonstrating compliance with Treatment Performance Requirement;
o Plan sheet page and detail number (if appropriate) of Drainage Management Areas (DMA) Exhibit
where construction details are provided for each DMA.
For DMAs using Low Impact Development Treatment Systems, provide:
o 85th percentile 24-hour storm event value, and basis of determination.
For DMAs using Biofiltration Systems, provide:
o Statement indicating why an LID treatment system was not appropriate;
o Surface loading rate approach, and basis of determination;-
(0.2 x per hour intensity, or 2 x 85th percentile hourly rainfall intensity);
o Calculations to demonstrate that the minimum surface reservoir volume is equal to the biofiltration
treatment system surface area time a depth of 6-inches;
o Construction detail (or reference to page on plans) which provides:
o Minimum planting depth
o Planting medium specifications. Either:
• Specify 60 to 70% ASTM C33 sand, with 30-40% compost , or
• Provide testing documentation demonstrating planting medium specified can minimally
infiltrate at a rate of 5 inches per hour)
o Plant selection consistent with Appendix L;
o Subsurface drainage/storage (gravel) layer with an area equal to the biofiltration treatment
system surface area and having a minimum depth of 12 inches;
o Underdrain with discharge elevation at top of gravel layer;
o No compaction of soils beneath the biofiltration facility (ripping/loosening of soils required if
compacted);
o No liners or other barriers interfering with infiltration, except for situations where lateral
infiltration is not technically feasible.
For DMAs using Non-Retention Based Treatment Systems, provide:
o Statement indicating why an LID, or Biofiltration treatment system was not appropriate
o Hydraulic Sizing Criteria used, and basis of determination (Volume = to 85th percentile, 24-hour storm, or flow
basis (2 x 85th percentile hourly rainfall intensity or 0.2 x inches per hour intensity)
Item 9.b. - Page 64
Performance Requirement 3: Runoff Retention SWCP Checklist
SITE ASSESSMENT MEASURES: (see table 3.5)
Include an exhibit and narrative of the opportunities and constraints to implementing LID Stormwater
Control measures based on the following items (as applicable):
D Site topography D Run-on characteristics (source and estimated runoff from
offsite which discharges to the project area)
D Hydrologic features including contiguous
natural areas, wetlands, watercourses, seeps, D Existing drainage infrastructure for the site and nearby
or springs areas, including the location of municipal storm drains
D Depth to seasonal high groundwater D Structures, including retaining walls
D Locations of groundwater wells used for D Utilities
drinking water
D Easements
D Depth to an impervious layer such as
Bedrock D Covenants
D Presence of unique geology (e.g., karst) D Zoning/Land Use
D Geotechnical hazards D Setbacks
D Documented soil and/or groundwater D Open space requirements
Contamination
D Other pertinent overlay(s)
D Soil types and hydrologic soil groups
D Veoetative cover/trees
SITE DESIGN MEASURES
Include in narrative, and provide supporting exhibits as necessary, to demonstrate that the project
design has implemented the following design strategies (as applicable}
DESIGN STRATEGY MEANS OF DEMONSTRATING COMPLIANCE
Define the development envelope and protected Site Stormwater Assessment Exhibit.
areas, identifying areas that are most suitable for
1. development and areas to be left undisturbed.
Conserve natural areas, including existing trees, Site Stormwater Assessment Exhibit with native vegetation,
2. other vegetation, and soils overlain with development footprint
Limit the overall impervious footprint of the Discussion regarding other building configurations
3. project considered (and ultimately rejected)
Construct streets, sidewalks, or parking lot aisles Discussion on minimum allowable widths, and rationale for
to the minimum widths necessary, provided that using larger values (if applicable) or confirmation that
4. public safety or mobility uses are not minimum values were used (where applicable).
compromised
Set back development from creeks, wetlands, Discussion on set-back dimensions chosen.
5. and riparian habitats
Conform the site layout along natural landforms Within the Drainage Management Area (OMA) Exhibit, show
Topo survey with existing and planned contours cut and fill
6. lines. Discussion of grading approach.
Avoid excessive grading and disturbance of Exhibit with native vegetation, overlain with planned
7. vegetation and soils disturbed area limits.
Item 9.b. - Page 65
Performance Requirement 3: Runoff Retention SWCP Checklist Continued
STORMWATER STRUCTURAL CONTROL MEASURE SIZING
For Overall project,
D Certification statement indicating that the selection, sizing, and design of Stormwater Control
measures meets the applicable Water Quality Treatment and Runoff Retention Performance
Requirements, or, if not achievable
o Provide documentation of the volume of runoff for which compliance cannot be achieved
on-site and the associated off-site compliance volume
o Statement of intent to comply with Water Quality Treatment and Runoff Retention
Performance Requirements through an Alternative Compliance Agreement
D Documentation demonstrating percentage of the project's Equivalent Impervious Surface Area
dedicated to retention-based Stormwater Control Measures
For each OMA,
D Indicate sizing strategy used
o Hydrologic analysis and sizing methods
o Locally/regionally calibrated continuous simulation model that results in equivalent
optimization of on-site runoff retention volumes
o Hydrologic analysis and sizing methods, equally effective in optimizing on-site retention
volumes of the runoff generated by the rainfall events specified
D Provide supporting calculations demonstrating compliance with Runoff Retention Performance
Requirement
D Indicate if a ten percent adjustment (based on technical infeasibility) is included in design
approach
D Indicate if off-site mitigation is included in design approach
NOTE: This checklist must be included with every project application (except for projects
deemed EXEMPT). See Figure xxx to determine if your project is considered exempt, or
regulated.
Item 9.b. - Page 66
Performance Requirement 4: Peak Management SWCP Checklist
Project Level Documentation, identify
o Point source discharge locations
o Hydraulic Report demonstrating that post development storm water runoff peak flows discharged
from the site do not exceed pre-project peak flows for the 2-through 10-yer storm events)
o Certification that on-site water quality treatment measures have been met on site, or if not
achievable:
o Documentation of the volume of runoff for which compliance cannot be achieved on site and the
associated off-site compliance requirements
o Statement of intent to comply with Water Quality Treatment Performance Requirement through
Alternative Compliance
NOTE: This checklist must be included with every project application (except for projects
deemed EXEMPT). See Figure xxx to determine if your project is considered exempt, or
regulated.
Item 9.b. - Page 67
Performance Requirement 5: Special Circumstances SWCP Checklist
Project Level Documentation, identify
o Which types of Special Circumstances apply
D Which Watershed Management Zones (WMZ) the project is located in
o Identification if the project is located atop of a designated Groundwater Basin
D Proposed Performance Requirement modifications based on special circumstances
o Peak Management
o Runoff Retention
For highly altered channels,
D Vicinity map indicating channel location relative to project, and downstream receiving waters
D Narrative, and supporting calculations (as applicable) regarding anticipated impacts to downstream
waters
For intermediate flow control facilities,
D Vicinity map indicating location of intermediate flow control facilities relative to project, and
downstream receiving waters
D Quantification of pre-project tributary area to intermediate flow control facility performance
D Quantification of proposed post-project tributary area to intermediate flow control facility
Performance
o Summarize flow control performance data (pre and post) and include supporting performance
information based on numeric, hydraulic modeling, including flow volumes, durations and velocities
D Narrative, and supporting calculations (as applicable) regarding anticipated impacts to downstream
Waters
o Vicinity map delineating location of historic lake and/or wetlands relative to project
D Supporting technical information to substantiate the request
D Narrative, and supporting calculations (as applicable) regarding anticipated impacts to downstream
Waters
o Stamped submittal (by registered professional engineer, geologist, architect, and/or landscape
architect)
NOTE: This checklist must be included with every project application (except for projects
deemed EXEMPT). See Figure 1 to determine if your project is considered exempt, or
regulated.
Item 9.b. - Page 68
Alternate Compliance (Off-Site Compliance) SWCP Checklist
The City will only consider alternative compliance for projects able to demonstrate technical infeasibility. Projects
approved for alternative compliance must identify and secure rights to use an alternative site. Potential off-site
compliance alternative projects might include green streets retrofits, off-site drainage features, riparian habitat
restoration projects, etc. The off-site compliance alternative project must be located within the same watershed as the
project and retain the storm water retention volume required by the original project. It is recommended that
discussions with City staff begin early in the development process regarding the acceptability of an off-site
compliance alternative project.
Project Level Documentation, identify
o Indication of site conditions which are resulting in LID technical infeasibility
o Depth to seasonable high groundwater limits infiltration and/or prevents construction of subgrade stormwater
control measures
o Depth to an impervious layer such as bedrock limits infiltration
o Sites where soil types significantly limit infiltration
o Sites where pollutant mobilization in the soil or groundwater is a documented concern
o Space constraints (e.g., infill projects, some redevelopment projects, high density development)
o Geotechnical hazards
o Stormwater Control Measures located within 100 feet of a groundwater well used for drinking water
o Incompatibility with surrounding drainage system (e.g., project drains to an existing stormwater collection
system whose elevation or location precludes connection to a properly functioning treatment or flow control
facility)
o Indication of site conditions which are resulting in Bioretention technical infeasibility
o Biofiltration is not compatible with surrounding drainage system
o Location available for biofiltration facility is in an area with identified erosion or landslide hazards
o Location available for biofiltration facility is on a slope equal to or in excess of 8 percent
o Location available for biofiltration facility is within 50-feet from the projected top of the slope (using projected
angle of repose) that is great than 20%
o Areas where runoff potentially contains industrial wastes
o Areas where there is a higher risk of concentrated spills (such as gas stations, truck stops)
o Site-specific hydrologic and/or design analysis conducted and endorsed by a registered professional engineer,
geologist, architect, and/or landscape architect, demonstrating that compliance with the applicable numeric Post-
Construction Stormwater Management requirements is technically infeasible.
o Schedule for completion of offsite project with milestone dates to identify funding, design, and construction of the
off-site project(s) Note, Approved Watershed or Regional Plans, and projects situated within designated Urban
Sustainability Areas are currently not acceptable reasons for pursuing off-site compliance
NOTE: This checklist must be included with every project application (except for projects
deemed EXEMPT}. See Figure xxx to determine if your project is considered exempt, or
regulated.
Item 9.b. - Page 69
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Item 9.b. - Page 70