PC R 23-2383RESOLUTION NO. 23-2383
A RESOLUTION OF THE PLANNING COMMISSION OF THE
CITY OF ARROYO GRANDE APPROVING CONDITIONAL
USE PERMIT 23-001 AND CERTIFYING AN ADDENDUM TO
A PREVIOUSLY CERTIFIED MITIGATED NEGATIVE
DECLARATION; LOCATION — AN APPROXIMATELY ONE -
MILE STRETCH OF CORBETT CREEK BETWEEN EAST
BRANCH STREET AND 379 CORBETT CANYON ROAD;
APPLICANT — HALLIE RICHARDS, COASTAL SAN LUIS
RESOURCE CONSERVATION DISTRICT
WHEREAS, the project site is an approximately one -mile stretch of Corbett Creek located
between East Branch Street and 379 Corbett Canyon Road, and
WHEREAS, the applicant has filed Conditional Use Permit 23-001 to complete a
comprehensive restoration project; and
WHEREAS, the Staff Advisory Committee considered the project on September 8, 2022
and February 2, 2023 and recommended approval of the project; and
WHEREAS, in accordance with the California Environmental Quality Act (CEQA)
Guidelines, staff conducted an Initial Study (IS) and prepared a Mitigated Negative
Declaration (MND) and Mitigation Monitoring and Reporting Program (MMRP). The IS/MND
was certified by the Planning Commission on April 16; 2013. Due to the age of the
environmental document, the applicant prepared an addendum to the IS/MND. The
previously certified IS/MND, the MMRP and the addendum are included as Exhibits "B" and
"C" and "D," respectively, in this attached Resolution; and
WHEREAS, the Planning Commission of the City of Arroyo Grande has reviewed the project
at a duly noticed public hearing on June 6, 2023; and.
WHEREAS, the Planning Commission finds, after due study, deliberation, and public
hearing, the following circumstances exist:
Conditional Use Permit Findings:
1. The proposed use is permitted within the subject district pursuant to the
provisions of this section and complies with all the applicable provisions of this
title, the goals, and objectives of the Arroyo Grande General Plan, and the
development policies and standards of the City.
The proposed use of the site fora restoration project is permitted with approval
of a conditional use permit by the City Council after receiving a
recommendation from the Planning Commission and the project complies
with all applicable provisions of the Arroyo Grande General Plan and
Municipal Code.
2. The proposed use would not impair the integrity and character of the district
RESOLUTION NO. 23-2383
PAGE 2
in which it is to be established or located.
The proposed use of the site for a creek restoration project will not impair the
integrity of the project site due to the intent of the project to return the site to
its natural condition.
3. The site is suitable for the type and intensity of use or development that is
proposed.
The site is an approximately one -mile stretch of Corbett Creek, which is
suitable for a creek restoration project and meets the development standards
of the Arroyo Grande Municipal Code.
4. There are adequate provisions for water, sanitation, and public utilities and
services to ensure public health and safety.
The project involves restoring a one -mile section of creek to a natural state.
Based on the project description, no utilities will be required at the site. No
aspect of the proposed project is anticipated to be overly impactful to the
existing services. Conditions of approval developed for the project will
additionally ensure public services are minimally impacted.
5. The proposed use will not be detrimental to the public health, safety or welfare
or materially injurious to properties and improvements in the vicinity.
The proposed use will not be detrimental to the public health, safety or
welfare, nor materially injurious to properties or improvements in the vicinity,
as it will comply conditions of approval specifically developed for the project.
NOW, THEREFORE, BE IT RESOLVED that the Planning Commission of the City of Arroyo
Grande hereby approves Conditional Use Permit 23-001 as set forth in Exhibit "B", attached
hereto and incorporated herein by this reference, with the above findings and subject to the
conditions as set forth in Exhibit "A", attached hereto and incorporated herein by this
reference.
On motion by Commissioner Sackrison, seconded by Vice Chair Berlin, and by the following
roll call vote, to wit:
AYES:
Sackrison, Berlin, Buchanan and Maraviglia
NOES:
None
ABSENT:
Roof
the foregoing Resolution was adopted this 6"' day of June, 2023
RESOLUTION NO. 23-2383
PAGE 3
r
eamg& & -
AMIE mARAVIGLIA
CHAIR
;;L
-
4'
PATRICK HOLUB
SECRETARY TO THE COMMISSION
AS TO CONTENT:
BRIAN PEDROTTI
COMMUNITY DEVELOPMENT DIRECTOR
RESOLUTION NO. 23-2383
PAGE 4
EXHIBIT 'A'
CONDITIONS OF APPROVAL
CONDITIONAL USE PERMIT 23-001
CORBETT CREEK RESTORATION PROJECT
COMMUNITY DEVELOPMENT DEPARTMENT
PLANNING DIVISION
GENERAL CONDITIONS
The applicant shall ascertain and comply with all Federal, State, County and City
requirements as are applicable to this project.
2. The applicant shall comply with all conditions of approval for Conditional Use Permit
23-001.
3. This application shall automatically expire on June 6, 2025 unless a Lake and
Streambed Alteration permit is issued by the California Department of Fish and
Wildlife (CDFW). Thirty (30) days prior to the expiration of the approval, the applicant
may apply for an extension of one (1) year from the original date of expiration.
4. Development shall occur in substantial conformance with the plans presented to the
Planning Commission at the meeting of June 6, 2022 and marked Exhibit B.
5. The applicant shall agree to indemnify and defend at his/her sole expense any action
brought against the City, its present or former agents, officers, or employees because
of the issuance of said approval, or in any way relating to the implementation thereof,
or in the alternative, to relinquish such approval. The applicant shall reimburse the
City, its agents, officers, or employees, for any court costs and attorney's fees which
the City, its agents, officers or employees may be required by a court to pay as a result
of such action. The City may, at its sole discretion, participate at its own expense in
the defense of any such action but such participation shall not relieve applicant of
his/her obligations under this condition.
6. A copy of these conditions shall be incorporated into all construction documents.
7. At the time of application for construction permits, plans submitted shall show all
development consistent with the approved site plan, floor plan, architectural elevations
and landscape plan.
8. All conditions of this approval run with the land and shall be strictly adhered to, within
the time frames specified, and in an on-going manner for the life of the project. Failure
to comply with these conditions of approval may result in an immediate enforcement
action. If it is determined that violation(s) of these conditions of approval have
occurred, or are occurring, this approval may be revoked pursuant to Development
RESOLUTION NO. 23-2383
PAGE 5
Code Section 16.08.100.
GENERAL CONDITIONS
9. All project improvements shall be designed and constructed in accordance with the
most recent version of the City of Arroyo Grande Standard Specifications and
Engineering Standards.
10. Preserve existing survey monuments and vertical control benchmarks in compliance
with Standard Specifications Section 5-1.26A.
11. The applicant shall be responsible for obtaining an encroachment permit for all work
within a public right-of-way (City, County and/or Caltrans).
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INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION EXHIBIT C March 2013
Corbett Creek Floodplain and Stream Restoration Protect
>.
, 07� CITY- of INITIAL STUDY/
_ MITIGATED NEGATIVE
�cA DECLARATION
Map of Clark Property (APN 007-791-032)
Staff Project No. 13-001
Corbett Creek Floodplain and Stream Restoration Project
March 2013
Page 1 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project _
Project: Staff Project No. 13-001
Corbett Creek Floodplain and Stream Restoration Project
Lead Agency: City of Arroyo Grande
Document Availability:
City of Arroyo Grande
Community Development Department
300 East Branch Street
Arroyo Grande, CA 93420
Project Description:
The proposed project involves the acquisition by the Coastal San Luis Resource Conservation District
(RCD) of a conservation easement over the 12.5 -acre Clark Property located between Highway 227
(Carpenter Canyon Road) and Corbett Canyon Road and the design, permitting and construction of a
floodplain/sediment detention basin on the easement property. The project also includes channel
restoration of approximately nine hundred feet (90(Y) of Corbett Creek located downstream of the Clark
Property. Currently there are no identified implementation funds for the channel restoration
component of the project. The City will be directly involved in the project through permitting of the
floodplain/sediment detention basin design and implementation activities.
Summary Document Preparation:
Pursuant to Section 21082.1 of the California Environmental Quality Act, the City of Arroyo Grande (the
City) has independently reviewed and analyzed the Initial Study and Mitigated Negative Declaration for
the proposed project and finds that these documents reflect the Independent judgment of the City. The
City, as lead agency, also confirms that the project mitigation measures detailed in these documents are
feasible and will be implemented as stated in the Mitigated Negative Declaration.
7mCereMcClis ,AICP
unity Development Director
Kelly Heffe on, AICP
Associate Planner
Date
-3l� Z-/3
Date
Page 2 of 42
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION
Corbett Creek Floodplain and Stream Restoration Pro
Table of Contents:
March 2013
Introduction........................................................................................................................................... 5
Introduction and Regulatory Guidance.....................................................................................................5
LeadAgency..............................................................................................................................................5
Purpose and Document Organization.......................................................................................................6
Summaryof Findings.................................................................................................................................6
ProjectDescription........................................................................................................................................7
Introduction..............................................................................................................................................
7
Background and Need for Project.............................................................................................................9
Other Required Public Agency Approvals...............................................................................................10
RelatedProjects......................................................................................................................................10
EnvironmentalChecklist.............................................................................................................................11
ProjectInformation.................................................................................................................................11
Environmental Factors Potentially Affected...........................................................................................13
Determination.........................................................................................................................................13
Evaluation of Environmental Impacts.....................................................................................................14
EnvironmentalIssues..................................................................................................................................15
1. Aesthetics.............................................................................................................................................15
2. Agriculture and Forestry Resources....................................................................................................16
3. Air Quality..........................................................................................................................................16
4. Biological Resources............................................................................................................................18
5. Cultural Resources..............................................................................................................................21
6. Geology and Soils................................................................................................................................23
7. Greenhouse Gas Emissions.................................................................................................................25
8. Hazards and Hazardous Materials......................................................................................................
25
9. Hydrology and Water Quality.............................................................................................................26
^ 10. Land Use and Planning......................................................................................................................29
11. Mineral Resources.............................................................................................................................30
12. Noise.................................................................................................................................................30
13. Population and Housing....................................................................................................................32
14. Public Services...................................................................................................................................33
15. Recreation.........................................................................................................................................33
16. Transportation/Traffic.......................................................................................................................34
17. Utilities and Service Systems............................................................................................................34
Page 3 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Mandatory Findings of Significance............................................................................................................36
Summary of Mitieation Measures..............................................................................................................37
References..................................................................................................................................................43
Page 4 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION
Corbett Creek Floodplain and Stream Restoration Project
Introduction
March 2013
Introduction and Regulatory Guidance
The Initial Study/Mitigated Negative Declaration (IS/MND) has been prepared by the City of Arroyo
Grande (the City) to evaluate the potential environmental effects of the proposed project. This
document has been prepared in accordance with the California Environmental Quality Act (CEQA), Public
Resources Code §21000 et seq., and the State CEQA Guidelines, California Code of Regulations (CCR)
§15000 et seq.
An Initial Study is conducted by a lead agency to determine if a project may have a significant effect on
the environment [CEQA Guidelines §15063(a)]. If there is substantial evidence that a project may have a
significant effect on the environment, an Environmental Impact Report (EIR) must be prepared, in
accordance with CEQA Guidelines §15064(a). However, if the lead agency determines that revisions in
the project plans or proposals made by or agreed to by the applicant avoid, reduce or mitigate the
potentially significant effects to a less -than -significant level, a Mitigated Negative Declaration may be
prepared instead of an EIR [CEQA Guidelines §15070(b)]. The lead agency prepares a written statement
describing the reasons a proposed project would not have a significant effect on the environment and,
therefore, why an EIR need not be prepared. This IS/MND conforms to the content requirements under
CEQA Guidelines §15071.
Trustee and Responsible Agencies
The following public agencies have legal responsibilities for carrying out or approving portions of the
project. A responsible agency must actively participate in the lead agency's CEQA process, review the
lead agency's CEQA document, and use that document when making a decision on the project. The
responsible agency must rely on the lead agency's environmental document to prepare and issue its
own findings regarding the project.
• California Department of Fish and Wildlife (CDFW) — Regulatory agency
• Regional Water Quality Control Board (RWQCB) — Regulatory agency
• US Fish and Wildlife Service (FWS) — Regulatory agency
• US Army Corps of Engineers (USACE) — Regulatory agency
• California Coastal Conservancy (CCC) — Funder, grant contractor
• California Department of Water Resources (DWR) — Funder, grant contractor
• Coastal San Luis Resource Conservation District (RCD) — Project Manager
Lead Agency
The lead agency is the public agency with primary approval authority over the proposed project. In
accordance with CEQA Guidelines §15051(b)(1), "the lead agency will normally be an agency with
general governmental powers, such as a city or county, rather than an agency with a single or limited
purpose." The lead agency for the proposed project is the City of Arroyo Grande. The contact person for
the lead agency is:
Kelly Heffernon, AICP
Associate Planner
City of Arroyo Grande
Arroyo Grande, CA 93420
(805) 473-5420
Page 5 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Purpose and Document Organization
The purpose of this document is to evaluate the potential environmental effects of the proposed
project. Mitigation measures have been identified and incorporated into the project to eliminate any
potentially significant impacts or reduce them to a less -than -significant level.
This document is organized as follows:
• Introduction
This chapter provides an introduction to the project and describes the purpose and organization
of this document.
• Project Description
This chapter describes the reasons for the project, scope of the project, and project objectives.
• Environmental Setting, Potential Impacts and Mitigation Measures
This chapter identifies the significance of potential environmental impacts, explains the
environmental setting for each environmental issue, and evaluates the potential impacts
identified in the CEQA Environmental (Initial Study) Checklist. Mitigation measures are
incorporated, where appropriate, to reduce potentially significant impacts to a less -than -
significant level.
• Mandatory Findings of Significance
This chapter identifies and summarizes the overall significance of any potential impacts to
natural and cultural resources, cumulative impacts, and impact to humans, as identified in the
Initial Study.
• Summary of Mitigation Measures
This chapter summarizes the mitigation measures incorporated into the project as a result of the
Initial Study.
• References
This chapter identifies the references and sources used in the preparation of this IS/MND. It also
provides a list of those involved in the preparation of this document.
Summary of Findings
Section 3 of this document contains the Environmental (Initial Study) Checklist that identifies the
potential environmental impacts (by environmental issue) and a brief discussion of each impact resulting
from implementation of the proposed project.
In accordance with §15064(f) of the CEQA Guidelines, a Mitigated Negative Declaration shall be
prepared if the proposed project will not have a significant effect on the environment after the inclusion
of mitigation measures in the project. Based on the available project information and the
environmental analysis presented in this document, there is no substantial evidence that, after the
incorporation of mitigation measures, the proposed project would have a significant effect on the
environment. It is proposed that a Mitigated Negative Declaration be adopted in accordance with the
CEQA Guidelines.
Page 6 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION
Corbett Creek FloodMain and Stream Restoration Prol
Project Description
March 2013
Introduction
The City of Arroyo Grande (the City) has prepared this Initial Study/Mitigated Negative Declaration
(IS/MND) to evaluate the potential environmental effects of the Corbett Creek Floodplain and Stream
Restoration Project (the "Project"). The Project specifically involves RCD's acquisition of a 12.5 acre
conservation easement, and the design and construction of a sedimentation and flood reduction basin
on the easement property. This Initial Study also includes an analysis of a proposed sediment removal
and creek restoration project downstream along Corbett Creek intended to reduce flooding in that area.
Project Scope and Location
The project reach begins at the East Branch Street culvert and extends upstream approximately one (1)
mile to the north end of the Clark Property (APN 007-791-032). As indicated in Exhibit A below, the
focus of the Project area is identified as Reach 6. Additional environmental review will be performed for
Reaches 1 through 5 once a scope of work is better defined. This IS/MND addresses impacts for Reaches
1 through 5 where they are foreseeable.
Page 7 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Exhibit A
Page 8 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Background and Need for Project
A conservation easement and sedimentation reduction project is being sought on the subject property
as a strategic location to carry out inter -related goals of the California Department of Water Resources
Flood Protection Corridor Program and the City of Arroyo Grande's goals stated in the
Conservation/Open Space and Agricultural Element of the 2001 General Plan and 2007 Creek Resources
Protection Study (see Exhibit B below for delineation of easement area).
Exhibit B
IN THE CITY OF ARROYO GRANDE 0 125 250 500 Feet
I i i I i 1 i 11I
OEasement Boundary iyellowline)
Page 9 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
The project consists of two components as follows:
1. The acquisition by RCD of a conservation easement in perpetuity over 12.50 acres of the 15.79 -
acre Clark Property at the confluence of Carpenter Creek and Corbett Creek to act as a
floodplain and thereby attenuate peak flows. The conservation easement area will be used to
construct a sediment basin, a floodwater detention area and a riparian habitat enhancement
area. These easement acquisition and construction components of the project are identified in
a technical study (Swanson Hydrology and Geomorphology, 2006) as critical to alleviating
flooding on Corbett Creek and reducing stress on lower Arroyo Grande Creek through the
reduction of peak flows and fine sediment. These project components have also been identified
as providing an important location upon which to restore riparian and floodplain habitat within
an urban wildlife corridor. Most of the engineering design, permitting, implementation and
monitoring will be completed using grant funds obtained from the Department of Water
Resources (DWR) through the Urban Streams Restoration Program. The estimated sediment
delivery reduction provided by the site is approximately nine hundred (900) tons per year.
Specific elements of the project include the following:
• Conservation easement acquisition.
• Sedimentation reduction through construction of active and passive sedimentation
basins.
• Restoration of floodplain and riparian habitat.
Design and permitting for a channel restoration project to re-establish the channel geometry of
approximately nine hundred feet (900') of Corbett Creek (Reach 4) and thereby increasing flow
volumes. Issues that will be considered in the design process include a four -foot (4') high head
cut that is migrating upstream, sediment from uplands and developments that are clogging
stormwater ditches and Corbett Creek, the increase in wetlands and marsh plants in the creek
resulting in reduced creek flow volumes, and individual landowner's activities in the floodplain
that cause or encourage erosion. Currently there are no identified implementation funds for
this component of the project.
Other Required Public Agency Approvals
California Department of Fish and Wildlife
Regional Water Quality Control Board
US Fish and Wildlife Service
US Army Corps of Engineers
Related Projects
None.
Page 10 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Environmental Checklist
Project Information
Project Title: Corbett Creek Floodplain and Stream Restoration Project
(Staff Project No. 13-001)
Lead Agency Name & Address: City of Arroyo Grande
300 East Brach Street
Arroyo Grande, CA 93420
Contact Person & Telephone Kelly Heffernon, Associate Planner
Number: (805) 473-5420
Project Location: 1. APN 007-791-032 (Clark Property)
2. Corbett Creek reach (multiple properties)
Project Sponsor Name & Address: City of Arroyo Grande
300 East Brach Street
Arroyo Grande, CA 93420
General Plan Designation: 1. Low Density Residential (LD); Conservation Open Space (C/OS)
2. Low -Medium Density Residential (LM); Conservation
Open Space (C/OS)
Zoning: 1. Residential Hillside (RH); Public Facility (PF) (combining
designation for the portion of the property containing the creek
channel)
2. Residential Suburban (RS); Single Family (SF); Village Mixed Use
(VMU); Village Core Downtown (VCD); Public Facility (PF)
(combining designations for portions of properties containing the
creek channel)
Description of Project: Acquisition of a conservation easement and design and
implementation of a sediment reduction project for the purpose of
floodplain restoration, sediment capture and peak flow attenuation
along specific reaches of Corbett Creek.
Surrounding Land Uses: The Clark Property contains a barn, equestrian trails, corals and
vacant open space. Properties located downstream along the creek
channel are primarily developed with single family residences with
some commercially developed properties existing closer to the Village
Core area. Several of the properties along this stretch are vacant.
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INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Project Setting: The City of Arroyo Grande is located in the southwestern portion of
San Luis Obispo County, and the project site is located within the
northeast section of the City of Arroyo Grande. The City is 5.45
square miles in size and is bounded by the Cities of Grover Beach and
Pismo Beach to the southwest and west, and to the unincorporated
County to the north, east and south. U.S. 101 extents northwest and
southeast through the middle of the City, and Highway 227 runs east
from U.S. 101 through the Village Area. Residential Rural and
Suburban development characterize unincorporated areas to the
north and southeast, and Agricultural uses dominate the Arroyo
Grande Valley that extends northeast and south of the City. The
project area is the reach of Corbett Creek from the northern City
border to the village Commercial area in the center of the City at the
confluence of Arroyo Grande Creek. The project area includes
residential development adjacent to Corbett Creek except at the
Village Core where there are four parcels zoned Village Core/Village
Mixed Use upon which there is an existing unoccupied structure.
Plans have been approved to develop a grocery store.
The topography of the City ranges from moderate and steep hillsides
to the north of U.S. 101 to relatively flat parcels toward the center of
town, to moderate slopes further south. The project area has varying
topographical gradients with an approximate 2-5% slope northeast.
Corbett Creek runs north/south to Arroyo Grande Creek. The Wilmar
Avenue fault is a potentially active fault adjacent to the City, and the
Pismo fault underlies portions of Arroyo Grande but is inactive and
poses very low potential fault rupture hazard to the City. No known
active faults underlie the project area.
The Corbett Creek reach is one of three (3) main tributaries within the
City limits. The creek flows are generally perennial in the project
reach with higher flows in the winter and very low flow in the
summer. The area enjoys a Mediterranean climate with most
precipitation occurring from November to March. Corbett Creek
stream flows remain elevated in the spring as groundwater and
subsurface flows contribute to the stream. The subwatershed is
dominated by agriculture and rural residential land uses. At the
project reach the channel is not formally channelized; however,
encroachment activities by residents over the years have effectively
channelized portions of the creek. Vegetation within the project area
includes native and exotic grasses, native and exotic brush including
blackberry and Willow trees, and ornamental landscaping on the
residential properties.
Page 12 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Proiect
Environmental Factors Potentially Affected
The environmental factors checked below would be potentially affected by this project, involving at
least one impact that is a "Potentially Significant Impact", as indicated by the checklist on the following
pages:
❑ Aesthetics
® Biological Resources
❑ Greenhouse Gas Emissions
❑ Land Use/Planning
❑ Population/Housing
❑ Transportation/Traffic
❑ Agricultural Resources
® Cultural Resources
❑ Hazards & Hazardous Materials
❑ Mineral Resources
❑ Public Services
❑ Utilities/Service Systems
Determination
On the basis of this initial evaluation:
® Air Quality
❑ Geology/Soils
® Hydrology/Water Quality
® Noise
❑ Recreation
❑ Mandatory Findings of Significance
❑ I find that the proposed project COULD NOT have a significant effect on the environment and a
NEGATIVE DECLARATION will be prepared.
® I find that, although the original scope of the proposed project COULD have had a significant
effect on the environment, there WILL NOT be a significant effect because revisions/mitigations
to the project have been made by or agreed to by the applicant. A MITIGATED NEGATIVE
DECLARATION will be prepared.
❑ I find that the proposed project MAY have a significant effect on the environment and an
ENVIRONMENTAL IMPACT REPORT or its functional equivalent will be prepared.
❑ I find that the proposed project MAY have a "potentially significant impact" or "potentially
significant unless mitigated impact" on the environment. However, at least one impact has
been adequately analyzed in an earlier document, pursuant to applicable legal standards, and
has been addressed by mitigation measures based on the earlier analysis, as described in the
report's attachments. An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze
only the impacts not sufficiently addressed in previous documents.
❑ I find that, although the proposed project could have had a significant effect on the
environment, because all potentially significant effects have been adequately analyzed in an
earlier EIR or Negative Declaration, pursuant to applicable standards, and have been avoided or
mitigated, pursuant to -an-earlier EIR, including -revisions or mitigation -measures that are
imposed upon the proposed project, all impacts have been avoided or mitigated to a less -than -
significant level and no further action is required.
Kelly Heffernon, AICP Date
Associate Planner
Page 13 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek floodplain and Stream Restoration Project
Evaluation of Environmental Impacts
1. A brief explanation is required for all answers, except "No Impact", that are adequately
supported by the information sources cited. A "No Impact" answer is adequately supported if
the referenced information sources show that the impact does not apply to the project being
evaluated (e.g., the project falls outside a fault rupture zone). A "No Impact" answer should be
explained where it is based on general or project -specific factors (e.g., the project will not
expose sensitive receptors to pollutants, based on a project -specific screening analysis).
2. All answers must consider the whole of the project -related effects, both direct and indirect,
including off-site, cumulative, construction, and operational impacts.
3. Once the lead agency has determined that a particular physical impact may occur, the checklist
answers must indicate whether that impact is potentially significant, less than significant with
mitigation, or less than significant. "Potentially Significant Impact" is appropriate when there is
sufficient evidence that a substantial or potentially substantial adverse change may occur in any
of the physical conditions within the area affected by the project that cannot be mitigated
below a level of significance. If there are one or more "Potentially Significant Impact" entries, an
Environmental Impact Report (EIR) is required.
4. A "Mitigated Negative Declaration" (Negative Declaration: Less Than Significant with Mitigation
Incorporated) applies where the incorporation of mitigation measures, prior to declaration of
project approval, has reduced an effect from "Potentially Significant Impact" to a "Less Than
Significant Impact with Mitigation." The lead agency must describe the mitigation measures and
briefly explain how they reduce the effect to a less than significant level.
5. Earlier analyses may be used where, pursuant to the tiering, program EIR, or other CEQA
process, an effect has been adequately analyzed in an earlier EIR (including a General Plan) or
Negative Declaration [CCR, Guidelines for the Implementation of CEQA, § 15063(c)(3)(D)].
References to an earlier analysis should:
a) Identify the earlier analysis and state where it is available for review.
b) Indicate which effects from the environmental checklist were adequately analyzed in the
earlier document, pursuant to applicable legal standards, and whether these effects were
adequately addressed by mitigation measures included in that analysis.
c) Describe the mitigation measures in this document that were incorporated or refined from
the earlier document and indicate to what extent they address site-specific conditions for
this project.
6. Lead agencies are encouraged to incorporate references to information sources for potential
impacts into the checklist or appendix (e.g., general plans, zoning ordinances, biological
assessments). Reference to a previously prepared or outside document should include an
indication of the page or pages where the statement is substantiated.
7. A source list should be appended to this document. Sources used or individuals contacted
should be listed in the source list and cited in the discussion.
8. Explanation(s) of each issue should identify:
a) the criteria or threshold, if any, used to evaluate the significance of the impact addressed by
each question and
b) the mitigation measures, if any, prescribed to reduce the impact below the level of
significance.
Page 14 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek FloodJain and Stream Restoration Project
Environmental Issues
1. Aesthetics
Environmental Setting
The Clark Property is about 16 acres in size and is located adjacent to Corbett Creek, a tributary to
Arroyo Grande Creek near the confluence of Carpenter and Corbett Creeks. The portion of the property
to be encumbered with the proposed conservation easement consists primarily of open space, the creek
and riparian corridor, and several small isolated wetlands. An outbuilding and a series of fenced
pastures currently occupy most of the property, with approximately six (6) acres of land in seasonal
pasture. The conservation easement will encompass a portion of the fenced pasture area, but does not
include any structures. The project would utilize approximately 12.5 acres for a conservation easement
for the purpose of restoring a historic floodplain. The project would create a sedimentation basin,
expand a wetland area, construct an earthen berm around the detention area to impound additional
runoff, and install control structures. These improvements would help to attenuate peak storm flows,
thereby increasing flood protection to urban and agricultural areas downstream. The proposed project
would enhance the rural setting by placing existing open space in a perpetual conservation easement
and by adding riparian vegetation. There are no visual impacts anticipated.
Project improvements downstream along the Corbett Creek reach include channel restoration at
strategic locations. Improvements include removing a four foot (4') high head -cut that is migrating
upstream, removal of sediment, and strategic removal of vegetation to increase conveyance capacity.
These improvements have not yet been designed, but there are no expected visual impacts associated
with this component of the project.
Discussion
a -d: No impacts.
Page 15 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Have a substantial adverse affect on a scenic vista?
❑
❑
❑
b) Substantially damage scenic resources, including,
but not limited to, trees, rock outcroppings, and
❑
❑
❑
historic buildings within a state scenic highway?
c) Substantially degrade the existing visual character or
❑
❑
❑
quality of the site and its su6roundings?
d) Create a new source of substantial light or glare
which would adversely affect day or nighttime views in
❑
❑
❑
the area?
Discussion
a -d: No impacts.
Page 15 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Flood lain and Stream Restoration Project
2. Agriculture and Forestry Resources
Environmental Setting
The project area is not "Prime Farmland, Unique Farmland, or Farmland of Statewide Importance
(Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring
Program of the California Resources Agency", nor is it located near any Farmland.
* In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the
California Agricultural Land Evaluation and Site Assessment Model (1997), prepared by the California Department of
Conservation as an optional model for use in assessing impacts on agricultural and farmland.
Discussion
a -e: No impacts.
3. Air Quality
Environmental Setting
San Luis Obispo County is in non -attainment status for ozone (03), respireable particulate matter (PM10)
and vinyl chloride under the California Air Resource Board (CARB) standards. The County is in
attainment status for all other applicable CARB standards.
Page 16 of 43
Potentially Less Than Less Than
Significant
Significant Significant No Impact
Would the project:
Impact Mitigation Impact
Impact
a) Convert Prime Farmland, Unique Farmland, or
Farmland of Statewide Importance (Farmland), as
shown on the maps prepared pursuant to the
❑ ❑ ❑
Farmland Mapping and Monitoring Program of the
California Resources Agency, to non-agricultural use?
b) Conflict with existing zoning for agricultural use or a
❑ ❑ ❑
Williamson Act contract?
c) Conflict with existing zoning for, or cause rezoning
of, forest land (as defined in Public Resources Code
section 12220)g)), timberland (as defined by Public
❑ ❑ ❑ ED
Resources Code section 4526), .or timberland zoned
Timberland Production (as defined by Government
Code section 51104(8))?
d) Result in the loss of forest land or conversion of
❑ ❑ ❑
forest land to non -forest use?
e) Involve other changes in the existing environment
which, due to their location or nature, could result in
❑ ❑ ❑
conversion of Farmland to non-agricultural use?
* In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the
California Agricultural Land Evaluation and Site Assessment Model (1997), prepared by the California Department of
Conservation as an optional model for use in assessing impacts on agricultural and farmland.
Discussion
a -e: No impacts.
3. Air Quality
Environmental Setting
San Luis Obispo County is in non -attainment status for ozone (03), respireable particulate matter (PM10)
and vinyl chloride under the California Air Resource Board (CARB) standards. The County is in
attainment status for all other applicable CARB standards.
Page 16 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Discussion
a: No impacts.
b -c: The San Luis Obispo County Air Pollution Control District (APCD) has developed the CEQA Air
Quality Handbook to evaluate project specific impacts and determine if air quality mitigation measures
are needed, or if potentially significant impacts could result. The City refers to this Handbook for all
projects subject to CEQA. Although the construction phase of the project is below the thresholds for
significance, some mitigation is recommended. Construction for this project includes grading to expand
the wetland area and to create the sedimentation basin. The "operation" phase of this project would
include periodic maintenance of the sedimentation basin and is considered insignificant. It is
anticipated that sedimentation removal might occur every five (5) to ten (10) years, and would largely
depend on the severity of storm conditions.
According to the general operational screening criteria in the APCD Handbook, the grading associated
with the proposed project is not expected .to generate potentially significant air quality impacts.
However, emissions associated with project construction could affect adjacent properties and would
add to the cumulatively significant effect that results in basin -wide exceedance of air quality standards.
These temporary fugitive dust and combustion emissions can impact local air quality. Implementation
of the following mitigation measures will reduce air quality impacts to a less than significant level:
MM 3.1: The following conditions shall be included on all project plans and adhered to for all
grading -related permits:
• Reduce the amount of disturbed area where possible.
• Use water trucks or sprinkler systems in sufficient quantities to prevent airborne dust
from leaving the site. Increase watering frequency when wind speeds exceed 15 MPH.
Reclaimed (non -potable) water shall be used whenever possible.
• All dirt stockpile areas should be sprayed daily or as . needed using reclaimed (non -
potable) water when feasible.
Page 17 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Conflict with or obstruct implementation of the
❑
❑
❑
applicable air quality plan?
b) Violate any air quality standard or contribute
substantially to an existing or projected air quality
❑
❑
®
❑
violation?
c) Result in a cumulatively considerable net increase of
any criteria pollutant for which the project region is in
non -attainment under an applicable federal or state
❑
®
❑
❑
ambient air quality standard (including releasing
emissions which exceed quantitative thresholds for
ozone precursors)?
d) Expose sensitive receptors to substantial pollutant
❑
❑
❑
concentrations?
e) Create objectionable odors affecting a substantial
❑
❑
❑
number of people?
Discussion
a: No impacts.
b -c: The San Luis Obispo County Air Pollution Control District (APCD) has developed the CEQA Air
Quality Handbook to evaluate project specific impacts and determine if air quality mitigation measures
are needed, or if potentially significant impacts could result. The City refers to this Handbook for all
projects subject to CEQA. Although the construction phase of the project is below the thresholds for
significance, some mitigation is recommended. Construction for this project includes grading to expand
the wetland area and to create the sedimentation basin. The "operation" phase of this project would
include periodic maintenance of the sedimentation basin and is considered insignificant. It is
anticipated that sedimentation removal might occur every five (5) to ten (10) years, and would largely
depend on the severity of storm conditions.
According to the general operational screening criteria in the APCD Handbook, the grading associated
with the proposed project is not expected .to generate potentially significant air quality impacts.
However, emissions associated with project construction could affect adjacent properties and would
add to the cumulatively significant effect that results in basin -wide exceedance of air quality standards.
These temporary fugitive dust and combustion emissions can impact local air quality. Implementation
of the following mitigation measures will reduce air quality impacts to a less than significant level:
MM 3.1: The following conditions shall be included on all project plans and adhered to for all
grading -related permits:
• Reduce the amount of disturbed area where possible.
• Use water trucks or sprinkler systems in sufficient quantities to prevent airborne dust
from leaving the site. Increase watering frequency when wind speeds exceed 15 MPH.
Reclaimed (non -potable) water shall be used whenever possible.
• All dirt stockpile areas should be sprayed daily or as . needed using reclaimed (non -
potable) water when feasible.
Page 17 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
• Exposed ground areas that are planned to be reworked more than one (1) month after
initial grading should be sown with a fast -germinating native grass seed and watered
until vegetation is established.
• All areas to be paved (i.e. access road to the sediment basin) should be completed as
soon as possible.
• All trucks hauling dirt, sand, soil or other loose materials are to be covered or shall
maintain at least two (2) feet of freeboard (minimum vertical distance between top of
load and top of trailer) in accordance with CVC Section 23114.
• Streets shall be swept at the end of each day if visible soil material is carried onto
adjacent paved roads. Water sweepers with reclaimed (non -potable) water should be
used where feasible.
• Diesel idling shall not be permitted.
• Signs that specify the no idling requirement shall be posted and enforced at the
construction site.
• Use of alternative -fueled equipment is recommended whenever possible.
• The contractor shall designate a person or persons to monitor and implement these
measures as necessary to minimize dust complaints, reduce visible emissions below 20%
opacity and to prevent the transport of dust off-site. The name and telephone number
of such persons shall be provided to the Air Pollution Control District (APCD) prior to the
start of any grading -related activities. (See MM 9.1 for erosion control measures).
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
MM 3.2: All portable equipment (50 horsepower or greater) used during grading operations
must be issued a permit by either the California Air Resources Board (CARB) or the APCD.
(Contact the APCD Engineering Division at (805) 781-5912 for specific information regarding
permitting requirements prior to start of the project).
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
d -e: No impacts.
4. Biological Resources
Environmental Setting
The project area includes the confluence of Corbett Creek and Carpenter Canyon Creek as well as the
confluence of Corbett Creek and Arroyo Grande Creek. Corbett Creek is a perennial creek that carries
flow except in drought years. The property has a long history of livestock grazing, and there has been
some modification of natural hydrology by re -alignment of the creeks and construction of a berm.
To determine the extent and quality of wetland habitat on the project site, and whether portions of the
project area were eligible for wetland protection and restoration through the Wetland Reserve Program
Page 18 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floo&lain and Stream Restoration Project
(WRP), a report was conducted by the Natural Resources Conservation Service (NRCS) in December
2006. According to the report, the Clark Property does not contain any land that would be eligible for
the Wetland Reserve Program. The site contains small areas of natural wetlands in four (4) delineations
and the remaining land subject to the conservation easement is considered non -wetland.
The project site contains a variety of non-nativeand native plant species, with willows being the
dominant native tree species. The prevailing understory species present include German ivy, poison
hemlock, California blackberry, hoary nettle, poison oak, and morning glories (Denise Duffy and
Associates, 2003). According to the Tally Ho Creek Planning Project Technical Memo Appendices
prepared by Waterways Consulting, Inc. (June 2010), there are several identified special status plant and
wildlife species that are likely present, although were not observed during the site inventory. These
include Hoover's bent grass (Agrostis hooveri), black -flowered figwort (Scrophuldria atrata), San
Bernardino aster (Symphyotricham defollatum), California red -legged frog (Rana aurora draytonii),
Southwestern pond turtle (Actinemys marmorata pallid), and the Yellow Warbler (Dendroica petechia).
The U.S. Fish and Wildlife Service (USFWS) and California Department of Fish and Wildlife (CDFW) have
regulatory responsibility for the protection of special status plant and wildlife species. "Special status"
species are selected for protection because they are rare and/or subject to population and habitat
declines. Special status is a general term for species that are afforded varying levels of regulatory
protection.
Page 19 of 43
Potentially Less Than Less Than
Significant
Significant Significant No Impact
with
Would the project:
Impact Mitigation Impact
a) Have a substantial adverse effect, either directly or
through habitat modification, on any species identified
as a sensitive, candidate, or special status species in
❑ ® ❑ ❑
local or regional plans, policies, or regulations, or by
the California Department of Fish and Wildlife or the
U.S. Fish and Wildlife Service?
b) Have a substantial adverse effect on any riparian
habitat or other sensitive natural community identified
in local or regional plans, policies, or regulations, or by
❑ ® ❑ ❑
the California Department of Fish and Wildlife or the
U.S. Fish and Wildlife Service?
c) Have a substantial adverse effect --on. federally
protected wetlands, as defined by §404 of the Clean
Water Act (including, but not limited to, marsh, vernal
❑ ❑ ® ❑
pool, coastal, etc.) through direct removal, filling,
hydrological interruption, or other means?
d) Interfere substantially with the movement of any
native resident or migratory fish or wildlife species or
with established native resident or migratory wildlife
❑ ❑ ® ❑
corridors, or impede the use of native wildlife nursery
sites?
e) Conflict with any local policies or ordinances
protecting biological resources, such as a tree
❑ ❑ ❑
preservation policy or ordinance?
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INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
f) Conflict with the provisions of an adopted Habitat
Conservation Plan, Natural Community Conservation
Plan, or other approved local, regional, or state habitat
conservation plan?
Discussion
a -d: With the mitigation measures identified below, it is not anticipated that the project will have a
significant impact on biological resources due to the historic equestrian use of the site and the short
duration of construction/grading activities. The site is dominated by non-native plants except for
willows. The purpose of creating the sedimentation basin and enhancing the floodplain area is to first
impede flooding downstream, and second to enhance the native habitat. It is expected that the long
term benefits of restoring the floodplain and riparian habitat will outweigh short term impacts.
Although the project will incorporate requirements for any necessary permits from the California
Department of Fish and Wildlife (CDFW) and United States Fish and Wildlife Service (USFWS), several
mitigation measures are included to offset any potential short term impacts. The following measures
are primarily designed to promote habitat avoidance.
MM 4.1: Construction/grading shall take place after the breeding season for the Yellow Warbler
(April — July) to limit noise impacts. If construction/grading must start during this time period,
surveys of nesting birds within the project vicinity shall be completed by a qualified wildlife
biologist. If the surveys identify active nests of the Yellow Warbler within the project vicinity, all
earthmoving activities shall cease until the chicks have fledged. The biologist shall provide the
lead agency and responsible agencies with a written report of survey findings, and shall specify
when the project work may safely commence.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager (in consultation with the U.S. Fish and
Wildlife Service (USFWS) prior to proceeding with work)
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit
MM 4.2: A qualified wildlife biologist shall complete and submit to the lead agency and
responsible agencies a pre -construction survey for California red -legged frogs and Southwestern
pond turtles. The survey shall be conducted during the time period when these species are
known to be active. If no individuals are found, construction may proceed. If individuals are
found during the initial investigation, the biologist shall conduct clearance surveys for these
species approximately one (1) week prior to construction. Individuals found within the
construction area will either be relocated to similar, adjacent habitats at least fifty (50) yards
outside of the project area, or held in captivity until construction is complete. The project area
shall be monitored during construction and appropriate measures taken to ensure that the
individuals of relocated species do not move into the construction area. The decision of
whether to relocate the animals shall be made by the biologist, although all mitigation activities
would have to occur within the framework of any permits issued by the USFWS and CDFG.
Page 20 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager (in consultation with the U.S. Fish and
Wildlife Service (USFWS) prior to proceeding with work)
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit and during construction
MM 4.3: A qualified botanist shall conduct an initial site survey to map occurrence of Hoover's
bent grass, San Bernardino aster and black -flowered figwort. If sensitive plant species are found
on site and determined to be potentially impacted, the botanist shall prepare procedures that
ensure no net loss of plants. These include, but are not limited to, designating avoidance areas,
transplanting the plant populations to an equivalent location on site, or replaced in-kind with
new plants at a ratio of two (2) plants replaced for each one (1) lost or at a ratio acceptable to
the botanist. The transplanted or replaced plants shall be monitored over a five (5) year period.
Any plants lost during this time period shall be replaced. The botanist shall prepare a planting,-
irrigation
lanting;irrigation and maintenance plan that includes these provisions. If the botanist concludes that
avoidance is a viable option, locations determined to be potentially impacted will be flagged
against inadvertent or unintentional damage.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager (in consultation with the U.S. Fish and
Wildlife Service (USFWS) prior to proceeding with work)
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit
MM 4.4. The applicant shall acquire appropriate resource agency permits and undertake
protection measures as required by those agencies.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Coastal San Luis Resource Conservation District
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit
e -f: No impacts.
5. Cultural Resources
Environmental Setting
Creeks are a focal area of concern for the purposes of cultural resource sensitivity due to the pre -history
and historical activity that occurred along and extending from creeks. The Central Coastal Information
Center under contract to the State Office of Historic Preservation (OHP) helps implement the California
Historical Resources Information System (CHRIS). It integrates information on new resources and known
resources into CHRIS, supplies information on resources and surveys to governments and supplies lists
of consultants qualified to conduct historic preservation fieldwork within the area. The California
Archaeological Site Inventory is the collection of Site Records, which has been acquired and managed by
the Information Centers and the OHP since 1975. According to these records, no known cultural site is
located in the immediate project vicinity. Of the nineteen (19) site investigations conducted within a
half mile radius of the project site, four (4) of which were on adjoining properties, there was only one (1)
Page 21 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
site that revealed any positive results for archaeological resources, which was located about 0.4 mile
south of the project site near Paulding Middle School.
By virtue of the project area including the confluence of two (2) creeks, there may be a likelihood of
prehistoric or early historic occupation or use of the site even though there are no known sites in the
vicinity. Additionally, the proposed project requires a limited amount of surface excavation for the
purposes of collection of fine sediment and floodplain restoration.
Discussion
a -c: Although it is not anticipated that there are any impacts to archaeological/cultural resources,
implementation of the mitigation measures below will ensure that no impacts will occur.
MM 5.1: In the event that prehistoric cultural materials or historic cultural materials are
encountered, work in the immediate vicinity of the finds shall be suspended until reviewed by
an archaeologist, and the City shall be notified immediately should such resources be
discovered. The archaeologist shall work as quickly as possible to permit resumption of
construction activities. It is preferred that location data of finds be recorded using a hand-held
global positioning system (GPS) receiver.
If human remains are encountered and determined to be Native American in origin, the San Luis
Obispo County coroner will notify the Native American Heritage Commission (NAHC) within 24
hours of the find. The NAHC shall identify the person or persons it believes to be the most likely
descendent of the deceased Native American. The most likely descendent may make
recommendations for means of treating or disposing of the human remains and any associated
grave goods as provided in Public Resources Code Section 5097.98.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timine: During construction
MM 5.2: The note below shall be placed on the grading and improvement plans for the project:
"If human remains (burials) are encountered, the County Coroner shall be contacted
immediately (805-781-4513). In the event that previously unidentified potentially
significant cultural resources are discovered, an archaeologist shall have. the authority to
Page 22 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Cause a substantial adverse change in the
significance of a historical resource, as defined in
❑
❑
®
❑
§15064.5?
b) Cause a substantial adverse change in the
significance of an archaeological resource, pursuant to
❑
®
❑
❑
§15064.5?
c) Disturb any human remains, including those interred
❑
®
❑
❑
outside of formal cemeteries?
Discussion
a -c: Although it is not anticipated that there are any impacts to archaeological/cultural resources,
implementation of the mitigation measures below will ensure that no impacts will occur.
MM 5.1: In the event that prehistoric cultural materials or historic cultural materials are
encountered, work in the immediate vicinity of the finds shall be suspended until reviewed by
an archaeologist, and the City shall be notified immediately should such resources be
discovered. The archaeologist shall work as quickly as possible to permit resumption of
construction activities. It is preferred that location data of finds be recorded using a hand-held
global positioning system (GPS) receiver.
If human remains are encountered and determined to be Native American in origin, the San Luis
Obispo County coroner will notify the Native American Heritage Commission (NAHC) within 24
hours of the find. The NAHC shall identify the person or persons it believes to be the most likely
descendent of the deceased Native American. The most likely descendent may make
recommendations for means of treating or disposing of the human remains and any associated
grave goods as provided in Public Resources Code Section 5097.98.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timine: During construction
MM 5.2: The note below shall be placed on the grading and improvement plans for the project:
"If human remains (burials) are encountered, the County Coroner shall be contacted
immediately (805-781-4513). In the event that previously unidentified potentially
significant cultural resources are discovered, an archaeologist shall have. the authority to
Page 22 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION
Corbett Creek floodalain and Stream Restoration Project
March 2013
divert or temporarily halt ground disturbance operations in the area of discovery to allow
evaluation of potentially signfcant cultural resources in consultation with Northern
Chumash Tribal Council. For significant cultural resources, a Research Design and Data
Recovery Program to mitigate impacts shall be prepared by the consulting archaeologist
and approved by the City, then carried out using professional archaeological methods. If
it can be demonstrated that a project will cause damage to a unique archaeological
resource, the City may require reasonable efforts to be made to permit any or all of
these resources to be preserved in place or left in an undisturbed state."
Level of Significance: I Less than significant impact
Imalementina Responsibility: I Construction Manaeer
Monitoring Agency: City of Arroyo Grande, Community
Timina: Prior to issuance of aradina permit
6. Geology and Soils
Environmental Setting
The site has varying topographical gradients but generally consist of a 2-5% northeasterly slope. The
soils on the Corbett Creek watershed are derived from soft, highly erodible sandstones. High levels of
sediment in the creek have come from several locations of erosion and flooding events. The highest
profile erosion sources came from the clearing and grading of an upslope property on James Way for a
housing development. In 2001, a combination of heavy rains and soils with a high to very high hazard
rating for water erosion led to the sedimentation of the James Way stormwater ditch and Corbett Creek,
in turn causing flooding to adjacent homes. Homes along Corbett Creek in some cases are as little as
twenty feet (20') from the creek and are not elevated. The sediment was deposited in Corbett Creek,
raising the streambed. Sediment accumulation has created marsh -like wetland areas that alter the form
and function of the creek, diminishing the in -stream habitat and the conveyance of water and sediment.
In addition to erosion, expansion of the urban fringe, road development and increases in impervious
surfaces have resulted in changes in the timing and magnitude of peak flows in the creek. There are
small berms in some localized areas along the north side of the active channel built by landowners.
Another factor affecting stream function is a four foot (4') high head -cut in the creek (as of 2007). If the
head -cut was to progress upstream 2,700 feet, approximately 7,000 cubic yards of sediment would
mobilize (Swanson Hydrology & Geomorphology, 2008) and be transported downstream to Arroyo
Grande Creek, impacting steelhead habitat and increasing flooding challenges in the Zone 1/1A flood
control channel.
No active faulting is known to exist on or close to the subject property. The project is not within a
known area containing serpentine or ultramafic rock or soils (i.e. low risk of naturally occurring
asbestos).
Page 23 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Discussion
a: No impacts.
b: The project is intended to alleviate risks from increasing head -cuts and deposition of sediment. The
project does not alter geotechnical requirements or permit additional construction in geologically
sensitive or hazardous areas. The project description integrates development and implementation of
both short and long term Best Management Practices (BMPs) to address construction and long term
maintenance of the sedimentation basins on the Clark Property, design of the head -cut remediation and
BMPs for landowners on the project area.
c -e: No impacts.
Page 24 of 43
Potentially Less Than Less Than
Significant
Significant Significant No Impact
with
Would the project:
Impact Mitigation Impact
a) Expose people or structures to potential substantial
adverse effects, including the risk of loss, injury, or
death involving:
i) Rupture of a known earthquake fault, as
delineated on the most recent Alquist-Priolo
Earthquake Fault Zoning Map, issued by the State
Geologist for the area, or based on other
❑ ❑ ❑
substantial evidence of a known fault? (Refer to
Division of Mines and Geology Special Publication
42.)
ii) Strong seismic ground shaking?
iii) Seismic -related ground failure, including
liquefaction?
iv) Landslides?
b) Result in substantial soil erosion or the loss of
❑ ❑ ® ❑
topsoil?
c) Be located on a geologic unit or soil that is unstable,
or that would become unstable, as a result of the
project and potentially result in on- or off-site
❑ ❑ ❑
landslide, lateral spreading, subsidence, liquefaction,
or collapse?
d) Be located on expansive soil, as defined in Table 18-
1-6 of the Uniform Building Code (1994), creating
❑ ❑ ❑
substantial risks to life or property?
e) Have soils incapable of adequately supporting the
use of septic tanks or alternative waste disposal
❑ ❑ ❑ ED
systems, where sewers are not available for the
disposal of waste water?
Discussion
a: No impacts.
b: The project is intended to alleviate risks from increasing head -cuts and deposition of sediment. The
project does not alter geotechnical requirements or permit additional construction in geologically
sensitive or hazardous areas. The project description integrates development and implementation of
both short and long term Best Management Practices (BMPs) to address construction and long term
maintenance of the sedimentation basins on the Clark Property, design of the head -cut remediation and
BMPs for landowners on the project area.
c -e: No impacts.
Page 24 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
7. Greenhouse Gas (GHG) Emissions
Environmental Setting
The project area includes residential development adjacent to Corbett Creek except at the Village Core
where there are four parcels zoned Village Core/Village Mixed Use. The Clark Property is mostly
undeveloped and contains a barn, equestrian trails and corals. Project construction is limited to creation
of a sedimentation basin and expansion of the floodplain within defined areas. Short term greenhouse
gas (GHG) emissions would be generated from equipment used for grading operations and are
considered less than significant. There is not an operational phase to this project except for periodic
(every 5-10 years) maintenance of the sedimentation basin. Therefore, GHG emissions cease once the
initial construction is complete.
Potentially Less Than Less Than
Significant Significant Significant No Impact
with
Would the project: Impact Mitigation Impact
a) Generate greenhouse gas emissions, either directly
or indirectly, that may have a significant effect on the ❑ ❑ ® ❑
environment?
b) Conflict with an applicable plan, policy or regulation
adopted for the purpose of reducing the emissions of ❑ ❑ ❑ED
greenhouse gases?
Discussion
a: The amount of GHG emissions from construction activities do not exceed the cumulative impact
thresholds established by the San Luis Obispo County Air Pollution Control District (APCD). It should be
noted that Mitigation Measures 3.1 and 3.2 address equipment and idling requirements that have the
dual benefit of reducing GHG emissions.
b: No impacts.
8. Hazards and Hazardous Materials
Environmental Setting
There are no known hazards or hazardous materials associated with the project site.
Page 25 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant No Impact
Would the project:
Impact
Mitigation
Impact
a) Create a significant hazard to the public or the
environment through the routine transport, use, or
❑
❑
❑
disposal of hazardous materials?
b) Create a significant hazard to the public or the
environment through reasonably foreseeable upset
and/or accident conditions involving the release of
❑
❑
® ❑
hazardous materials, substances, or waste into the
environment?
Page 25 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Protect
c) Emit hazardous emissions or handle hazardous or
acutely hazardous materials, substances, or waste
❑ ❑ ❑
within one-quarter mile of an existing or proposed
school?
d) Be located on a site which is included on a list of
hazardous materials sites, compiled pursuant to
❑ ❑ Cl
Government Code §65962.5, and, as a result, create a
significant hazard to the public or environment?
e) Be located within an airport land use plan or, where
such a plan has not been adopted, within two miles of
a public airport or public use airport? If so, would the
❑ ❑ ❑
project result in a safety hazard for people residing or
working in the project area?
f) Be located in the vicinity of a private airstrip? If so,
would the project result in a safety hazard for people
❑ ❑ ❑
residing or working in the project area?
g) Impair implementation of or physically interfere
with an adopted emergency response plan or
❑ ❑ ❑
emergency evacuation plan?
h) Expose people or structures to a significant risk of
loss, injury, or death from wildland fires, including
❑ ❑ ❑
areas where wildlands are adjacent to urbanized areas
or where residences are intermixed with wildlands?
Discussion
b: The project as proposed does not pose a significant hazard to the public or the environment.
However, in the unlikely event that there is an equipment malfunction producing an oil or gas spill,
procedures shall be followed as outlined under MM 9.1 (preparation of a Storm Water Pollution
Prevention Plan).
a, c- h: No impacts.
9. Hydrology and Water Quality
Environmental Setting
The project area includes the confluence of Corbett and Carpenter Canyon Creeks as well as the
confluence of Corbett and Arroyo Grande Creeks. Except for drought years, Corbett Creek maintains
perennial flow and meanders from the City limits near Highway 227 -to Arroyo Grande Creek in the
commercial core of the City's Village area. It has an active low flow channel/bank full morphology that
narrows to approximately two-four feet (2'-4') wide near Arroyo Grande Creek. The creek travels
through the backyards of residences on Tally Ho Road where there is persistent flooding. There is a four
foot (4') high head -cut in the creek that was initially observed by field crews in 2007. If the head -cut
were to progress upstream 2,700 feet, approximately 7,000 cubic yards of sediment would mobilize
(Swanson Hydrology & Geomorphology, 2008) and be transported downstream to Arroyo Grande Creek,
impacting steelhead habitat and increasing flooding challenges in, the Zone 1/1A flood control channel.
The project is intended to restore the riparian habitat and provide flood protection.
Construction/grading activities and exposed soil could cause temporary erosion; however,
implementation of Best Management Practices (BMPs) that are integrated into the project description
and the mitigation measures below will mitigate the impacts to less that significant.
Page 26 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Flood Iain and Stream Restoration Pro'ect
Discussion
a, c -f, h -i: Potentially significant impacts from soil erosion and an increase in sediment and turbidity to
Arroyo Grande Creek could result from project grading and construction. Potentially significant impacts
on hydrology and water quality from construction related activities can be reduced to a less -than -
significant level with implementation of the mitigation measures listed below.
The project site is within a floodway where waters flood onto horse pastures and therefore water
quality impacts from equestrian use and manure accumulation may also be a concern. The project may
bring surface water more frequently in contact with pastures and manure. However, the project would
Page 27 of 43
Potentially Less Than Less Than
Significant
Significant Significant No Impact
with
Would the project:
Impact Mitigation Impact
a) Violate any water quality standards or waste
❑ ® ❑ ❑
discharge requirements?
b) Substantially deplete groundwater supplies or
interfere substantially with groundwater recharge,
such that there would be a net deficit in aquifer
volume or a lowering of the local groundwater table
❑ ❑ ❑
level (e.g., the production rate of pre-existing nearby
wells would drop to a level that would not support
existing land uses or planned uses for which permits
have been granted)?
c) Substantially alter the existing drainage pattern of
the site or area, including through alteration of the
❑ ® ❑ ❑
course of a stream or river, in a manner which would
result in substantial on- or off-site erosion or siltation?
d) Substantially alter the existing drainage pattern of
the site or area, including through alteration of the
course of a stream or river, or substantially increase
❑ ® ❑ ❑
the rate or amount of surface runoff in a manner
which would result in on- or off-site flooding?
e) Create or contribute runoff water which would
exceed the capacity of existing or planned stormwater
❑ ® ❑ ❑
drainage systems or provide substantial additional
sources of polluted runoff?
f) Substantially degrade water quality?
❑ ® ❑ ❑
g) Place housing within a 100 -year flood hazard area,
as mapped on a federal Flood Hazard Boundary or
❑ ❑ ❑
Flood Insurance Rate Map, or other flood hazard
delineation map?
h) Place structures that would impede or redirect flood
❑ ® ❑ ❑
flows within a 100-yearflood hazard area?
i) Expose peopleor structures to -a-significant risk of
loss,. injury, or death from flooding, including flooding
❑ ® ❑ ❑
resulting from the failure of a levee or dam?
j) Result in inundation by seiche, tsunami, or mudflow?
❑ ❑ ❑
Discussion
a, c -f, h -i: Potentially significant impacts from soil erosion and an increase in sediment and turbidity to
Arroyo Grande Creek could result from project grading and construction. Potentially significant impacts
on hydrology and water quality from construction related activities can be reduced to a less -than -
significant level with implementation of the mitigation measures listed below.
The project site is within a floodway where waters flood onto horse pastures and therefore water
quality impacts from equestrian use and manure accumulation may also be a concern. The project may
bring surface water more frequently in contact with pastures and manure. However, the project would
Page 27 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
not worsen the water quality situation since no more horses would be added to the site, and some of
the area currently used for horse corrals and pasture would be allocated to floodwater detention and
riparian habitat enhancement. It is unknown at this time what the water quality impacts from nitrogen
or bacteria will be from the project. Water quality monitoring will be carried out as required by the
Storm Water Pollution Prevention Plan. The property owner is interested in BMPs to manage manure
through composting. These BMPs would reduce potential bacteria pollutant loading, and would be
implemented separately from this project. The continued equestrian use is not considered a potentially
significant impact.
There is a potential for berm failure that could impact downstream properties. This potential will be
addressed through the design process, and applicable design standards will be used.
MM 9.1: The applicant shall prepare a Storm Water Pollution Prevention Plan (SWPPP) and
Erosion Control Plan that specifies the implementation of Best Management Practices (BMPs) to
avoid and minimize water quality impacts as required by the Regional Water Quality Control
Board (RWQCB). At a minimum, the SWPPP and Erosion Control Plan shall include:
• Designation of equipment and supply staging and storage areas at least 100 feet
from the outside edge of the creek 25 -foot setback area. All vehicle parking,
routine equipment maintenance, fueling, minor repair, etc., and soil and
material stockpile, shall be done only in the designated staging area.
• Major vehicle/equipment maintenance, repair, and equipment washing shall be
performed off site.
• A wet and dry spill cleanup plan that specifies reporting requirements and
immediate clean up to ensure no residual soil, surface water or groundwater
contamination would remain after clean up.
• Designating concrete mixer washout areas at least 100 feet from outside edge
of the creek 25 -foot setback with the use of appropriate containment or reuse
practices.
• A temporary and excess fill stockpile and disposal plan that ensures that no
detrimental affects to receiving waters would result.
• Required site preparation and erosion control BMPs for any work that may need
to be completed after October 15.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
MM 9.2: To reduce erosion hazards due to construction activities, grading shall be
minimized, and project contractors shall use runoff and sediment control structures, and/or
establish a permanent plant cover on side slopes following construction.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Page 28 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Timing: Prior to issuance of grading permit and during construction
MM 9.3: Erosion control and bank stabilization measures shall be implemented for any
work that requires access to the creek, subject to CDFW approval through a Streambed
Alteration Permit. These measures shall be clearly indicated on the grading plan.
Level of Significance: I Less than significant impact
Imolementine Resoonsibilitv: I Coastal San Luis Resource Conservation District
of Arroyo Grande, Community Development Dept.
Prior to issuance of grading permit and during construction
MM 9.4: All temporary fill placed during project construction shall be removed at project
completion and the area restored to approximate pre -project contours and topography.
Level of Significance: Less than significant impact _
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to final inspection
MM 9.5: The project is located within a regulatory floodway. The applicant shall obtain
all required permits from regulatory agencies (City of Arroyo Grande, Regional Water Quality
Control Board, US Army Corps of Engineers, Ca. Dept. of Fish and Wildlife, etc.) and meet any
relevant FEMA requirements associated with a regulatory floodway as necessary.
Level of Sisni
Less than significant im
Implementing Resoonsibilitv: I Coastal San Luis Resource Conservation District i
I Monitoring Agency: I City of Arroyo Grande, Community Development Dept.
Prior to issuance of grading permit
b, g, j: No impacts.
10. Land Use and Planning
Environmental Setting -
Surrounding uses are identified on Page 10 of the Initial Study. The proposed project was reviewed for
consistency with policy and/or regulatory documents and appropriate land use (Land Use Element,
Development Code, and Zoning Map). Outside the channel of Corbett Creek, the Clark Property is zoned
for low density residential development at a density of 0.67 dwelling units/acre (a total of up to ten
units). This project includes a conservation easement in perpetuity for 12.5 acres leaving a potential
residential density of up to two (2) dwelling units. There are several antiquated lots in the project area
that have been developed over time and the built density along Corbett Creek exceeds that of the low
density residential designation. City policy C/OS 2 states that the City is to "safeguard important
environmental and sensitive biological resources contribution to healthy, functioning ecosystems".
Conserving land for the purposes of localized and downstream flood protection and habitat restoration
is consistent with the City's General Plan.
Page 29 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Discussion
a -c: No impacts.
11. Mineral Resources
Environmental Setting
The project site is not located within an area known to contain mineral resources. The site is not
designated in the 2001 General Plan or identified in the Integrated Program EIR prepared for the
General Plan as having locally -important mineral resources. There are no permitted mining operations
located within the City limits of Arroyo Grande.
Potentially
Less Than
Significant
Less Than
Significant
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Physically divide an established community?
❑
❑
❑
ED
b) Conflict with the applicable land use plan, policy, or
b) Result in the loss of availability of a locally
regulation of any agency with jurisdiction over the
important mineral resource recovery site delineated
❑
project (including, but not limited to, a general plan,
❑
❑
❑
specific plan, local coastal program, or zoning
plan?
ordinance) adopted for the purpose of avoiding or
mitigating an environmental effect?
c) Conflict with any applicable habitat conservation
❑
❑
❑
plan or natural community conservation plan?
Discussion
a -c: No impacts.
11. Mineral Resources
Environmental Setting
The project site is not located within an area known to contain mineral resources. The site is not
designated in the 2001 General Plan or identified in the Integrated Program EIR prepared for the
General Plan as having locally -important mineral resources. There are no permitted mining operations
located within the City limits of Arroyo Grande.
Discussion
a -b: No impacts.
12. Noise
Environmental Setting
The project site is primarily located within a low to medium density residential area. Existing ambient
noise in the vicinity of the project is primarily generated by vehicular traffic. The Noise Element of the
2001 General Plan includes goals and implementation measures designed to reduce noise impacts on new
development, and the City's Noise Ordinance is the primary implementing tool of the Noise Element
through specific noise standards.
Would the project:
Potentially Less Than
Significant Significant
Impact with
Mitigation
Less Than
Significant No Impact
Impact
Page 30 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant No Impact
Would the project:
Impact
Mitigation
Impact
a) Result in the loss of availability of a known mineral
resource that is or would be of value to the region and
❑
❑
❑ ED
the residents of the state?
b) Result in the loss of availability of a locally
important mineral resource recovery site delineated
❑
❑
❑
on a local general plan, specific plan, or other land use
plan?
Discussion
a -b: No impacts.
12. Noise
Environmental Setting
The project site is primarily located within a low to medium density residential area. Existing ambient
noise in the vicinity of the project is primarily generated by vehicular traffic. The Noise Element of the
2001 General Plan includes goals and implementation measures designed to reduce noise impacts on new
development, and the City's Noise Ordinance is the primary implementing tool of the Noise Element
through specific noise standards.
Would the project:
Potentially Less Than
Significant Significant
Impact with
Mitigation
Less Than
Significant No Impact
Impact
Page 30 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION
Corbett Creek Floodplain and Stream Restoration Project
March 2013
a) Generate or expose people to noise levels in excess
Less than significant impact
of standards established in a local general plan or
❑ ® ❑ ❑
noise ordinance, or in other applicable local, state, or
City of Arroyo Grande, Community Development Dept.
federal standards?
During construction
b) Generate or expose people to excessive
❑ ❑ ❑
groundborne vibrations or groundborne noise levels?
c) Create a substantial permanent increase in ambient
noise levels in the vicinity of the project (above levels.
❑ ❑ ❑
without the project)?
d) Create a substantial temporary or periodic increase
in ambient noise levels in the vicinity of the project, in
❑ ® ❑ ❑
excess of noise levels existing without the project?
e) Be located within an airport land use plan or, where
such a plan has not been adopted, within two miles of
a public airport or public use airport? if so, would the
❑ ❑ ❑
project expose people residing or working in the
project area to excessive noise levels?
f) Be in the vicinity of a private airstrip? If so, would
the project expose people residing or working in the
❑ ❑ ❑
project area to excessive noise levels?
Discussion
a, d: Noise impacts associated with short term construction are expected to be minimal due to the need for
limited surface excavation. Existing ambient noise in the vicinity of the project site is generated by vehicular
traffic on Highway 227. The average sound levels during construction could exceed the threshold criteria
when equipment is operating. This is considered a potentially significant impact that can be mitigated to a
less -than -significant level with implementation of the below mitigation measures. There are no long-
term or operational increases to ambient noise levels.
MM 12.1: Construction activities shall be restricted to the hours of 8:00 AM to 5:00 PM Monday
through Friday. On-site equipment maintenance and servicing shall be confined to the same
hours.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: During construction
MM 12.2: All construction equipment utilizing internal combustion engines shall be required to
have mufflers that are in good condition. Stationary noise sources shall utilize noise reducing
engine housing enclosures or noise screens.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
During construction
Page 31 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
MM 12.3: A note shall be placed on the construction plans that no more than two (2) pieces of
major earth moving equipment shall be allowed to operate simultaneously.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
MM 12.4: All residential units located within five hundred feet (500') of the construction site
shall be sent a notice regarding the construction schedule of the project. A clearly legible sign
shall also be posted at the project site. All notices and the signs shall indicate the expected
dates and duration of construction activities, as well as provide a telephone number that
residents can call to resolve any concerns about construction noise.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timins: Prior to issuance of grading permit and during construction
b -c, a -f: No impacts.
13. Population and Housing
Environmental Setting
The project site is located within an established low and medium density residential area. Placing 12.5
acres of the roughly 16 -acre Clark Property into a conservation easement would appear to reduce the
residential development potential. However, because the 12.5 -acre property is located within a
floodplain area, it is unlikely that housing opportunities are lost. With 3.5 acres remaining of the 16 acre
site, two (2) homes could be constructed at a density of 0.67 dwelling units per acre under the
Residential Hillside (RH) zoning district. Downstream along the Corbett Creel reach, the only properties
with development potential (i.e. vacant) are zoned Village Mixed Use (VMU) and Village Core (VC).
These zoning designations allow commercial and residential development. The proposed project would
not impede development of these properties.
Page 32 of 43
Potentially
Less Than
LessLess Than
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Induce substantial population growth in an area,
either directly (for example, by proposing new homes
❑
❑
❑
IR
and businesses) or indirectly (for example, through
extension of roads or other infrastructure)?
b) Displace substantial numbers of existing housing,
necessitating the construction of replacement housing
❑
❑
❑
19
elsewhere?
c) Displace substantial numbers of people,
necessitating the construction of replacement housing
❑
❑
❑
elsewhere?
Page 32 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Proiect
Discussion
a -c: No impacts.
14. Public Services
Environmental Setting
Public services to the project site are readily provided by the City of Arroyo Grande.
Discussion
a: No impacts.
15. Recreation
Environmental Setting
The project site is a private facility with recreational uses and is not a public facility. The property owner
utilizes the site primarily for corralling and grazing horses, with most of the site left in vacant open
space. The project will not affect any existing private or public parks within the area, either by creating
more demand for parks or diminishing the use of parks.
Potentially
Less Than
Significant
LessThan
Significant
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
impact
a) Result in significant environmental impacts from
regional parks or other recreational facilities, such that
❑
❑
❑
construction associated with the provision of new or
occur or be accelerated?
physically altered governmental facilities, or the need
b) Include recreational facilities or require the
for new or physically altered governmental facilities, to
❑
❑
❑
ED
maintain acceptable service ratios, response times, or
might have an adverse physical effect on the
other performance objectives for any of the public
services:
Fire protection?
❑
❑
❑
Police protection?
❑
❑
❑
Schools?
❑
❑
❑
Parks?
❑
❑
❑
Other public facilities?
❑
❑
❑
Discussion
a: No impacts.
15. Recreation
Environmental Setting
The project site is a private facility with recreational uses and is not a public facility. The property owner
utilizes the site primarily for corralling and grazing horses, with most of the site left in vacant open
space. The project will not affect any existing private or public parks within the area, either by creating
more demand for parks or diminishing the use of parks.
Page 33 of 43
Potentially
Less Than
Less Than
Significant
Significant
with
Significant No Impact
Would the project:
Impact
Mitigation
Impact
a) Increase the use of existing neighborhood and
regional parks or other recreational facilities, such that
❑
❑
❑
substantial physical deterioration of the facility would
occur or be accelerated?
b) Include recreational facilities or require the
construction or expansion of recreational facilities that
❑
❑
® ❑
might have an adverse physical effect on the
environment?
Page 33 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
Discussion
a: No impacts.
b: The site will continue to serve as an equestrian recreational use. The existing facilities will remain,
with some reduction in corral and grazing areas (see Exhibit B above under Background and Need for
Project).
16. Transportation/Traffic
Environmental Setting
The project site is located within an established low and medium density residential area with access
from Highway 227/Carpenter Canyon Road, Corbett Canyon Road, and Tally Ho Road where street
parking is available and level of service is acceptable (LOS C or better). The project does not generate
any trips that would impact the surrounding street network LOS or the backbone circulation system of
the City.
Discussion
a -g: No impacts.
17. Utilities and Service Systems
Environmental Setting
The project site is located within the incorporated City Limits of Arroyo Grande. Utilities are available
from both the City and other regional entities.
Page 34 of 43
Potentially
Less Than
Significant
Less Than
Significant
with
Significant
No Impact
Would the project:
Impact
Mitigation
Impact
a) Cause a substantial increase in traffic, in relation to
existing traffic and the capacity of the street system
(i.e., a substantial increase in either the number of
❑
❑
❑
19
vehicle trips, the volume to capacity ratio on roads, or
congestion at intersections)?
b) Exceed, individually or cumulatively, the level of
service standards established by the county congestion
❑
❑
❑
management agency for designated roads or
highways?
c) Cause a change in air traffic patterns, including
either an increase in traffic levels or a change in
❑
❑
❑
location, that results in substantial safety risks?
d) Contain a design feature (e.g., sharp curves or a
dangerous intersection) or incompatible uses (e.g.,
❑
❑
❑
farm equipment) that would substantially increase
hazards?
e) Result in inadequate emergency access?
❑
❑
❑
f) Result in inadequate parking capacity?
❑
❑
❑
g) Conflict with adopted policies, plans, or programs
supporting alternative transportation (e.g., bus
❑
❑
❑
ED
turnouts, bicycle racks)?
Discussion
a -g: No impacts.
17. Utilities and Service Systems
Environmental Setting
The project site is located within the incorporated City Limits of Arroyo Grande. Utilities are available
from both the City and other regional entities.
Page 34 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION
Corbett Creek Floodalain and Stream Restoration Pro,
Would the project:
a) Exceed wastewater treatment restrictions or
standards of the applicable Regional Water Quality
Control Board?
b) Require or result in the construction of new water
or wastewater treatment facilities or expansion of
existing facilities?
Would the construction of these facilities cause
significant environmental effects?
c) Require or result in the construction of new storm
water drainage facilities or expansion of existing
facilities?
d) Have sufficient water supplies available to serve the
project from existing entitlements and resources or
are new or expanded entitlements needed?
e) Result in a determination, by the wastewater
treatment provider that serves or may serve the
project, that it has adequate capacity to service the
project's anticipated demand, in addition to the
provider's existing commitments?
f) Be served by a landfill with sufficient permitted
capacity to accommodate the project's • solid waste
disposal needs?
g) Comply with federal, state, and local statutes and
regulations as they relate to solid waste?
Discussion
a -g: No impacts.
March 2013
Potentially
Less Than
Less Than
z
Significant
Significant
Significant
No Impact
Impact
with
Mitigation
Impact
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
z
❑
❑
❑
❑
❑
❑
Page 35 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floods)lain and Stream Restoration Proiect
Mandatory Findings of Significance
Discussion
a, c -d: The project is located within an established low and medium density residential area. The
purpose of the project is to reduce flooding downstream and will enhance a wetland habitat area.
Isolated prehistoric materials may be present on the project site; however, the site does not serve as an
example of a major period of California history or prehistory. The project will not cumulatively increase
traffic or the demand for public services and utilities. With implementation of the proposed mitigation
measures, the project will not cause substantial adverse effects on human beings or special status plant
or animal species, either directly or indirectly.
b: No impacts.
Page 36 of 43
Potentially Less Than Less Than
Significant
Significant Significant No Impact
with
Would the project:
Impact Mitigation Impact
a) Substantially degrade the quality of the
environment, substantially reduce the habitat of a fish
or wildlife species; cause a fish or wildlife population
to drop below self-sustaining levels; threaten to
eliminate a plant or animal community; substantially
❑ ❑ ® ❑
reduce the number or restrict the range of an
endangered, rare or threatened species; or eliminate
examples of the major periods of California history or
prehistory?
b) Have the potential to achieve short-term
environmental goals to the disadvantage of long-term
❑ ❑ ❑
environmental goals?
c) Have possible environmental effects that are
individually limited but cumulatively considerable?
"Cumulatively considerable" means that the
incremental effects of an individual project are
❑ ❑ ® ❑
significant when viewed in connection with the effects
of past projects, the effects of other current projects,
and the effects of possible future projects.
d) Cause substantial adverse effects on human beings,
❑ ❑ ® ❑
either directly or indirectly?
Discussion
a, c -d: The project is located within an established low and medium density residential area. The
purpose of the project is to reduce flooding downstream and will enhance a wetland habitat area.
Isolated prehistoric materials may be present on the project site; however, the site does not serve as an
example of a major period of California history or prehistory. The project will not cumulatively increase
traffic or the demand for public services and utilities. With implementation of the proposed mitigation
measures, the project will not cause substantial adverse effects on human beings or special status plant
or animal species, either directly or indirectly.
b: No impacts.
Page 36 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Pro ect
Summary of Mitigation Measures
MM 3.1: The following conditions shall be included on all project plans and adhered to for all
grading -related permits:
• Reduce the amount of disturbed area where possible.
• Use water trucks or sprinkler systems in sufficient quantities to prevent airborne dust
from leaving the site. Increase watering frequency when wind speeds exceed 15 MPH.
Reclaimed (non -potable) water shall be used whenever possible.
• All dirt stockpile areas should be sprayed daily or as needed using reclaimed (non -
potable) water when feasible.
• Exposed ground areas that are planned to be reworked more than one (1) month after
initial grading should be sown with a fast -germinating native grass seed and watered
until vegetation is established.
• All areas to be paved (i.e. access road to the sediment basin) should be completed as
soon as possible.
• All trucks hauling dirt, sand, soil or other loose materials are to be covered or shall
maintain at least two (2) feet of freeboard (minimum vertical distance between top of
load and top of trailer) in accordance with CVC Section 23114.
• Streets shall be swept at the end of each day if visible soil material is carried onto
adjacent paved roads. Water sweepers with reclaimed (non -potable) water should be
used where feasible.
• Diesel idling shall not be permitted.
• Signs that specify the no idling requirement shall be posted and enforced at the
construction site.
• Use of alternative -fueled equipment is recommended whenever possible.
• The contractor shall designate a person or persons to monitor and implement these
measures as necessary to minimize dust complaints, reduce visible emissions below 20%
opacity and to prevent the transport of dust off-site. The name and telephone number
of such persons shall be provided to the Air Pollution Control District (APCD) prior to the
start of any grading -related activities. (See MM 9.1 for erosion control measures).
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: During construction
MM 3.2: All portable equipment (50 horsepower or greater) used during grading operations
must be issued a permit by either the California Air Resources Board (CARE) or the APCD.
(Contact the APCD Engineering Division at (805) 781-5912 for specific information regarding
permitting requirements prior to start of the project).
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit and during construction
Page 37 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
MM 4.1: Construction/grading shall take place after the breeding season for the Yellow Warbler
(April — July) to limit noise impacts. If construction/grading must start during this time period,
surveys of nesting birds within the project vicinity shall be completed by a qualified wildlife
biologist. If the surveys identify active nests of the Yellow Warbler within the project vicinity, all
earthmoving activities shall cease until the chicks have fledged. The biologist shall provide the
lead agency and responsible agencies with a written report of survey findings, and shall specify
when the project work may safely commence.
I Level of Significance:
I Imolementine Responsibility:
Less than significant im
Construction Manager
Monitorina Aitencv: I City of Arroyo Grande, Community Development Dept. y
Timing:
Prior to issuance of,
it
MM 4.2: A qualified wildlife biologist shall complete and submit to the lead agency and
responsible agencies a pre -construction survey for California red -legged frogs and Southwestern
pond turtles. The survey shall be conducted during the time period when these species are
known to be active. If no individuals are found, construction may proceed. If individuals are
found during the initial investigation, the biologist shall conduct clearance surveys for these
species approximately one (1) week prior to construction. Individuals found within the
construction area will either be relocated to similar, adjacent habitats at least fifty (50) yards
outside of the project area, or held in captivity until construction is complete. The project area
shall be monitored during construction and appropriate measures taken to ensure that the
individuals of relocated species do not move into the construction area. The decision of
whether to relocate the animals shall be made by the biologist, although all mitigation activities
would have to occur within the framework of any permits issued by the USFWS and CDFG.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
MM 4.3: A qualified botanist shall conduct an initial site survey to map occurrence of Hoover's
bent grass, San Bernardino aster and black -flowered figwort. If sensitive plant species are found
on site and determined to be potentially impacted, the botanist shall prepare procedures that
ensure no net loss of -plants. These include, but are not limited to, designating avoidance areas,
transplanting the plant populations to an equivalent location on site, or replaced in-kind with
new plants at a ratio of two (2) plants replaced for each one (1) lost or at a ratio acceptable to
the botanist. The transplanted or replaced plants shall be monitored over a five (5) year period.
Any plants lost during this time period shall be replaced. The botanist shall prepare a planting,
irrigation and maintenance plan that includes these provisions. If the botanist concludes that
avoidance is a viable option, locations determined to be potentially impacted will be flagged
against inadvertent or unintentional damage.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development
Timina: Prior to issuance of grading permit
Page 38 of 43
INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
MM 4.4: The applicant shall acquire appropriate resource agency permits and undertake
protection measures as required by those agencies.
Level of Significance: Less than significant impact
Implementing Responsibility: Coastal San Luis Resource Conservation District
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit
MM 5.1: In the event that prehistoric cultural materials or historic cultural materials are
encountered, work in the immediate vicinity of the finds shall be suspended until reviewed by
an archaeologist, and the City shall be notified immediately should such resources be
discovered. The archaeologist shall work as quickly as possible to permit resumption of
construction activities. It is preferred that location data of finds be recorded using a hand-held
global positioning system (GPS) receiver.
If human remains are encountered and determined to be Native American in origin, the San Luis
Obispo County coroner will notify the Native American Heritage Commission (NAHC) within 24
hours of the find. The NAHC shall identify the person or persons it believes to be the most likely
descendent of the deceased Native American. The most likely descendent may make
recommendations for means of treating or disposing of the human remains and any associated
grave goods as provided in Public Resources Code Section 5097.98.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: During construction
MM 5.2: The note below shall be placed on the grading and improvement plans for the project:
"7f human remains (burials) are encountered, the County Coroner shall be contacted
immediately (805-789-4593). In the event that previously unidentified potentially
significant cultural resources are discovered, an archaeologist shall have the authority to
divert. or temporarily halt ground disturbance operations in the area of discovery to allow
evaluation _ ofpotentially signitcapt . cultural resources_ in ._consultation with Northern
Chumash Tribal Council. For significant cultural resources, a Research Design and Data
Recovery Program to mitigate impacts shall be prepared by the consulting archaeologist
and approved by the City, then carried out using professional archaeological methods. If
it can be demonstrated that a project will cause damage to a unique archaeological
resource, the City may require reasonable efforts to be made to permit any or all of
these resources to be preserved in place or left in an undisturbed state. "
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit
Page 39 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION
Corbett Creek Floodplain and Stream Restoration Pro
March 2013
MM 9.1: The applicant shall prepare a Storm Water Pollution Prevention Plan (SWPPP) and
Erosion Control Plan that specifies the implementation of Best Management Practices (BMPs) to
avoid and minimize water quality impacts as required by the Regional Water Quality Control
Board (RWQCB). At a minimum, the SWPP and Erosion Control Plan shall include:
• Designation of equipment and supply staging and storage areas at least 100 feet
from the outside edge of the creek 25 -foot setback area. All vehicle parking,
routine equipment maintenance, fueling, minor repair, etc., and soil and
material stockpile, shall be done only in the designated staging area.
• Major vehicle/equipment maintenance, repair, and equipment washing shall be
performed off site.
• A wet and dry spill cleanup plan that specifies reporting requirements and
immediate clean up to ensure no residual soil, surface water or groundwater
contamination would remain after clean up.
• Designating concrete mixer washout areas at least 100 feet from outside edge
of the creek 25 -foot setback with the use of appropriate containment or reuse
practices.
• A temporary and excess fill stockpile and disposal plan that ensures that no
detrimental affects to receiving waters would result.
• Required site preparation and erosion control BMPs for any work that may need
to be completed after October 15.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timine: Prior to issuance of grading permit and during construction
MM 9.2: To reduce erosion hazards due to construction activities, grading shall be
minimized, and project contractors shall use runoff and sediment control structures, and/or
establish a permanent plant cover on side slopes following construction.
Level of Significance:
Implementing Responsi
Monitoring Agency:
Timing:
Less than significant impact
Construction Manager
City of Arroyo Grande, Community Development Dept.
Prior to issuance of grading permit and during construction
MM 9.3: Erosion control and bank stabilization measures shall be implemented for any
work that requires access to the creek, subject to CDFW approval through a Streambed
Alteration Permit. These measures shall be clearly indicated on the grading plan.
Level of Significance: Less than significant impact
Implementing Responsibility: Coastal San Luis Resource Conservation District
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
Page 40 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
MM 9.4: All temporary fill placed during project construction shall be removed at project
completion and the area restored to approximate pre -project contours and topography.
L eve I of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to final inspection
MM 9.5: The project is located within a regulatory floodway. The applicant shall obtain
all required permits from regulatory agencies (City of Arroyo Grande, Regional Water Quality
Control Board, US Army Corps of Engineers, Ca. Dept. of Fish and Wildlife, etc.) and meet any
relevant FEMA requirements associated with a regulatory floodway as necessary.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Coastal San Luis Resource Conservation District
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Priorto issuance of grading permit
MM 12.1: Construction activities shall be restricted to the hours of 8:00 AM to 5:00 PM Monday
through Friday. On-site equipment maintenance and servicing shall be confined to the same
hours.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
During construction
MM 12.2: All construction equipment utilizing internal combustion engines shall be required to
have mufflers that are in good condition. Stationary noise sources shall utilize noise reducing
engine housing enclosures or noise screens.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Tuning: During construction
MM 12.3: A note shall be placed on the construction plans that no more than two (2) pieces of
major earth moving equipment shall be allowed to operate simultaneously.
Level of Significance: Less than significant impact
Implementing Responsibility: Construction Manager
Monitoring Agency: City of Arroyo Grande, Community Development Dept.
Timing: Prior to issuance of grading permit and during construction
Page 41 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Proiect
MM 12.4: All residential units located within five hundred feet (500') of the construction site
shall be sent a notice regarding the construction schedule of the project. A clearly legible sign
shall also be posted at the project site. All notices and the signs shall indicate the expected
dates and duration of construction activities, as well as provide a telephone number that
residents can call to resolve any concerns about construction noise.
Level of Significance:
Less than significant impact
Implementing Responsibility:
Construction Manager
Monitoring Agency:
City of Arroyo Grande, Community Development Dept.
Timing:
Prior to issuance of grading permit and during construction
Page 42 of 43
INITIAL STUDY / MITIGATED NEGATIVE DECLARATION March 2013
Corbett Creek Floodplain and Stream Restoration Project
References
Documents & Maps
1. Arroyo Grande General Plan
2. Arroyo Grande Municipal Code
3. Arroyo Grande Zoning Map
4. Arroyo Grande Existing Settings Report & Draft Arroyo Grande Existing Settings Report (2010)
S. Arroyo Grande Urban Water Management Plan
6. Arroyo Grande Stormwater Management Plan
7. San Luis Obispo Important Farmland Map (California Department of Conservation, 2006)
8. CEQA & Climate Change White Paper (CAPCOA, 2008)
9. Air Quality Handbook (SLO APCD, 2009)
10. Project Plans —Swanson Hydrology & Geomorphology
11. Site Inspection
12. Arroyo Grande Creek Erosion, Sedimentation and Flooding Alternatives Study, Swanson
Hydrology & Geomorphology, January 4, 2006
13. Letter from the Natural Resources Conservation Service regarding land eligibility report for Clark
WRO Offering, dated December 19, 2006
Page 43 of 43
CITY OF
ii CALIFORNIA
EXHIBIT D
MITIGATION MONITORING
AND REPORTING PROGRAM (MMRP)
Staff Project No. 13-001
Corbett Creek Floodplain and Stream Restoration Project
ADOPTED BY:
CITY OF ARROYO GRANDE
PLANNING COMMISSION
DATE:
APRIL 16, 2013
MMRP
Corbett Creek Floodplain and Stream Restoration Project
April 2013
Introduction
A Mitigated Negative Declaration (MND) was prepared to comply with the California
Environmental Quality Act (CEQA) for the Corbett Creek Floodplain and Stream
Restoration Project (the "Project"). The MND identified potential environmental impacts
as well as mitigation measures to reduce the impacts, where feasible.
CEQA requires that mitigation measures identified in environmental review documents
are implemented after a project is approved. Therefore, this Mitigation Monitoring and
Reporting Program (MMRP) has been prepared to ensure compliance with the adopted
mitigation measures during the pre -construction, construction, and post -construction
phases of the Project. The mitigation measures listed herein will be adopted by the
Arroyo Grande Planning Commission as part of the overall project approval.
Per Public Resources Code Section 21081.6 the measures listed in the table below
constitute the mitigation monitoring and/or reporting program that will reduce potentially
significant impacts to less than significant levels. These measures will become
conditions of approval (COAs) should the project be approved. The Lead Agency (City
of Arroyo Grande) or other Responsible Agencies, as specified in the following
measures, are responsible to verify compliance with these COAs.
Mitigation is defined by the California Environmental Quality Act (CEQA) as a measure
which:
• Avoids the impact altogether by not taking a certain action or parts of an action.
• Minimizes impacts by limiting the degree or magnitude of the action and its
implementation.
• Rectifies the impact by repairing, rehabilitating, or restoring the impacted
environment.
• Reduces or eliminates the impact over time by preservation and maintenance
operations during the life of the Project.
• Compensates for the impact by replacing or providing substitute resources or
environments.
The mitigation measures discussed in the table below have been identified as feasible
and effective in mitigating Project -related environmental impacts.
Project Location
The project reach begins at the Highway 227 Bridge over Tally Ho Creek and extends
upstream to the east end of the Clark property (APN 007-791-032).
Project Description
The proposed project involves the acquisition by the Coastal San Luis Resource
Conservation District (RCD) of a conservation easement over the 12.5 -acre Clark
Property located between Highway 227 (Carpenter Canyon Road) and Corbett Canyon
Road and the design, permitting and construction of a floodplain/sediment detention
basin on the easement property. The project also includes channel restoration of
approximately nine hundred feet (900') of Corbett Creek located downstream of the
2
MMRP
Corbett Creek Floodplain and Stream Restoration Project
April 2013
Clark Property. Currently there are no identified implementation funds for the channel
restoration component of the project. The City will be directly involved in the project
through permitting of the floodplain/sediment detention basin design and
implementation activities.
The Project goals are:
1. Increase sediment capture on floodplain easement
2. Increase flood attenuation on floodplain easement
3. Enhance floodplain wetland for flood attenuation and habitat
The Project will construct a sediment basin and enhance a floodplain wetland resulting
in an estimated 524 tons of sediment per year settled into a basin, reduced peak flows
in storms with recurrence intervals of ten (10) years or greater, and three (3) acres of
floodplain wetland enhanced.
Program Implementation and Monitoring
Each mitigation measure is described in the following format:
Requirements of
The description of the mitigation measures.
Measure
Mitigation Level
The level to which the impact is anticipated to be mitigated.
Implementing
The agency or individual that has the responsibility for
Responsibility
implementing or performing the measure.
Monitoring
The public agency that has the responsibility for monitoring to
Responsibility
ensure that the mitigation measure is effective in mitigating the
impact.
Compliance
The method used to verify compliance.
Standards
Timing The appropriate points in time at which the mitigation measure is
to be initiated and completed.
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777777
EXHIBIT E
Corbett Creek Floodplain and Stream Restoration
Project
Addendum to the
2013 Initial Study/ Mitigated Negative Declaration
SCH# 2013031045
Prepared by
Coastal San Luis Resource Conservation District
1203 Main St, Ste B, Morro Bay CA, 93442
COASTAL SAN LUIS
RESOURCE
CONSERVATION
DISTRICT
April 2023
Table of Contents
Table of Contents
2
Introduction
2
Previous Environmental Review
4
Corbett Creek Floodplain and Stream Restoration Project
6
1. Project Title
6
2. Lead Agency Name and Address
6
3. Contact Person and Phone Number
6
4. Project Location
6
5. Project sponsor's name and address
7
6. General Plan Designation
7
7. Zoning Designation
7
8. Description of Project
7
9. Surrounding Land Uses and Setting
9
10. Required Approvals
11
11. California Native American Tribal Consultation (AB 52)
11
Potential Impacts of Revised Project
11
Determination
14
References
14
Appendix A: 50% designs for Sediment Basin and Wetland Creation Project
Appendix B: 65% designs for Stream Channel Restoration
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
2
Introduction
This document is an Addendum to the 2013 Corbett Creek Floodplain and Stream Restoration Project
Initial Study and Mitigated Negative Declaration (MND) prepared in compliance with the California
Environmental Quality Act (CEQA) of 1970, Public Resources Code §21000, et seq., as amended, and
implementing CEQA Guidelines, Title 14, Chapter 3 of the California Code of Regulations. The 2013
Corbett Creek Floodplain and Stream Restoration Project MND evaluated the acquisition of a floodplain
easement on Corbett Creek as well as the restoration of approximately 900 feet of stream channel
downstream of the floodplain easement.
The purpose of this Addendum is to analyze the environmental impacts of the Corbett Creek Floodplain
and Stream Restoration Project, herein referred to as the "updated project." The updated project
includes more detailed engineered design plans that more accurately define project impacts. The
approved project, evaluated in the 2013 MND, included 50% conceptual engineered design plans with
approximate impacts. The updated project location and technical approach does not differ from the
approved project. Item 7, Description of Project, of this addendum defines the revised project and
describes the proposed changes in detail.
The City of Arroyo Grande assumed the role of Lead Agency for the development of the 2013 MND. Due
to changes in project roles, the Coastal San Luis Resource Conservation District (CSLRCD) took over the
role of Lead Agency for this project in 2023.
This Addendum has been prepared in accordance with the relevant provisions of CEQA and the CEQA
Guidelines. According to Section 15164(b) of the CEQA Guidelines, an addendum to a Negative
Deceleration is the appropriate environmental document in instances when "only minor technical
changes or additions are necessary or none of the conditions described in Section 15261 calling for the
preparation of a subsequent Negative Deceleration have occurred." Section 15162(a) of the CEQA
Guidelines states no subsequent Negative Deceleration shall be prepared for a project unless the lead
agency determines, on the basis of substantial evidence in the light of the whole record, one or more of
the following:
1. Substantial changes are proposed in the project which will require major revisions of the
previous EIR or negative declaration due to the involvement of new significant environmental
effects or a substantial increase in the severity of previously identified significant effects;
2. Substantial changes occur with respect to the circumstances under which the project is
undertaken which will require major revisions of the previous EIR or Negative Declaration due to
the involvement of new significant environmental effects or a substantial increase in the severity
of previously identified significant effects; or
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
3
3. New information of substantial importance, which was not known and could not have been
known with the exercise of reasonable diligence at the time the previous EIR was certified as
complete or the Negative Declaration was adopted, shows any of the following:
A. The project will have one or more significant effects not discussed in the previous MND,
B. Significant effects previously examined will be substantially more severe than shown in
the previous EIR;
C. Mitigation measures or alternatives previously found not to be feasible would in fact be
feasible, and would substantially reduce one or more significant effects of the project,
but the project proponents decline to adopt the mitigation measure or alternative; or
D. Mitigation measures or alternatives which are considerably different from those
analyzed in the previous EIR would substantially reduce one or more significant effects
on the environment, but the project proponents decline to adopt the mitigation
measure or alternative.
The increased detail included in the updated project are minor in the sense they would not create
potentially significant environmental impacts in addition to those already identified in the 2013 MND for
the approved Corbett Creek Floodplain and Stream Restoration Project. The updated project would also
not substantially increase the magnitude or severity of impacts that were previously identified. This
addendum includes a description of the updated project, and a discussion of the environmental impacts
of the proposed project change, focusing on Air Quality, Biological Resources, Tribal Cultural Resources,
Energy, Hydrology and Water Quality, and Noise.
CSLRCD Board of Directors shall consider this addendum with the 2013 Corbett Creek Floodplain and
Creek Restoration Project MND prior to making a CEQA decision on the updated project. The 2013
Corbett Creek Floodplain and Creek Restoration Project MND is available for review at the CSLRCD
offices, located at 1203 Main Street, suite B, in Morro Bay, 93442.
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
4
Previous Environmental Review
This section provides an overview of the 2013 Corbett Creek Floodplain and Creek Restoration Project
MND, to provide context for this addendum
2013 Corbett Creek Floodplain and Creek Restoration Proiect MND
The 2013 Corbett Creek Floodplain and Creek Restoration Project MND evaluates the potential
environmental effects of the acquisition of a 12.5 -acre conservation easement, the design and
construction of a sedimentation and flood reduction basin on the easement property, as well as an
analysis of a proposed sediment removal and creek restoration project downstream along Corbett Creek
intended to reduce flooding in that area. The project begins at the East Branch Street culvert and
extends upstream approximately one (1) mile to the north end of the Clark Property (APN 007-791-032).
A conservation easement and sedimentation reduction project is being sought on the subject property
as a strategic location to carry out inter -related goals of the California Department of Water Resources
Flood Protection Corridor Program and the City of Arroyo Grande's goals stated in the
Conservation/Open Space and Agricultural Element of the 2001 General Plan and 2007 Creek Resources
Protection Study.
The 2013 MND found that the following factors would be potentially affected by the project:
Air Quality: Analysis of project impacts determined that emissions associated with project
construction could affect adjacent properties and would add to the cumulatively significant effect
that results in basin -wide exceedance of air quality standards. These temporary fugitive dust and
combustion emissions can impact local air quality. Adopted mitigation measures MM3.1 and MM3.2
prescribe several actions to reduce emissions to less than significant.
Biolo ical Resources: Analysis of biological resources present in the project area determined that
adverse effects on sensitive species, including California red -legged frog, and riparian habitats would
be less than significant with mitigation. Adopted measures include avoiding nesting and mating
seasons for present sensitive species, pre -construction surveys, and appropriate regulatory
permitting.
Cultural Resources: Analysis of project impacts determined that adverse change in the significance of
an archaeological resource could be less than significant with mitigation. Adopted measures include
suspending work and contacting appropriate authorities if resources are encountered.
Hydrology/Water Quality: Analysis of hydrology and water resources within the project area
determined that project activities, including grading and filling could degrade or violate water quality
and waste discharge requirements, or alter existing drainage patterns resulting in erosion or
flooding. Analysis also determined that the project had the potential to impede or redirect flood
flows within a 100 -year flood hazard area and expose people or structures to a significant risk of loss,
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
5
injury, or death from flooding. Potentially significant impacts on hydrology and water quality from
construction related activities can be reduced to a less -than -significant level with implementation of
the several mitigation measures, including adoption of a project -specific Stormwater Pollution
Prevention Plan, establishment of permanent vegetation cover after project completion, installation
of erosion control practices during and following construction, and compliance with any and all
applicable regulation associated with floodway management.
Noise: Analysis of project impacts determined that the residents adjacent to the project area may be
exposed to noise levels in excess of established standards and that the project may generate periodic
or temporary increases in ambient noise levels. Noise impacts associated with short term
construction are expected to be minimal, and adopted mitigation measures, including restricted
work windows and engine mufflers will reduce impacts to less than significant.
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
6
Corbett Creek Floodplain and Stream
Restoration Project
1. Project Title
Corbett Creek Floodplain and Stream Restoration Project
2. Lead Agency Name and Address
Coastal San Luis Resource Conservation District
1203 Main St. Suite B Morro Bay, CA 93442
(805)772-4391
3. Contact Person and Phone Number
Hallie Richard, Conservation Programs Manager
805-772-4391, hrichard@coastalrcd.org
4. Project Location
1. Floodplain Easement: APN 007-791-032 (Clark Property)
2. Stream Restoration (APNs: 007-211-013, 007-211-007, 007-211-038, 007-211-030,
007-211-029, 007-252-013) See figure 1 below.
S. Project sponsor's name and address
Coastal San Luis resource Conservation District
1203 Main St, Ste B
Morro Bay, CA 93442
6. General Plan Designation
1. Low Density Residential (LD); Conservation Open Space (C/OS)
2. Low -Medium Density Residential (LM); Conservation Open Space (C/OS)
7. Zoning Designation
1. Residential Hillside (RH); Public Facility (PF) (combining designation for the portion of the
property containing the creek channel)
2. Residential Suburban (RS); Single Family (SF); Village Mixed Use (VMU); Village Core
Downtown (VCD); Public Facility (PF) (combining designations for portions of properties
containing the creek channel)
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
8. Description of Project
The project scope includes the acquisition of a conservation easement and design and
implementation of a sediment reduction project for the purpose of floodplain restoration,
sediment capture and peak flow attenuation along specific reaches of Corbett Creek. The
sediment reduction project includes two distinct components:
1. CSLRCD has acquired a conservation easement in perpetuity over 12.50 acres of the 15.79
acre Clark Property at the confluence of Carpenter Creek and Corbett Creek to act as a
floodplain and thereby attenuate peak flows. The conservation easement area will be used
to construct a sediment basin, a floodwater detention area and a riparian habitat
enhancement area (Appendix A). These easement acquisition and construction components
of the project are identified in a technical study (Swanson Hydrology and Geomorphology,
2006) as critical to alleviating flooding on Corbett Creek and reducing stress on lower Arroyo
Grande Creek through the reduction of peak flows and fine sediment. These project
components have also been identified as providing an important location upon which to
restore riparian and floodplain habitat within an urban wildlife corridor. Final engineering
design, permitting, implementation and monitoring are anticipated to be completed using
grant funds obtained from the Department of Water Resources (DWR) through the Urban
Streams Restoration Program or State Coastal Conservancy. Secured funding is contingent
upon commitment from project beneficiaries (City of Arroyo Grande, SLO Co Flood Control
Zones 3 and 1/1A) for long-term maintenance of the sediment basins. The estimated
sediment delivery reduction provided by the site is approximately nine hundred (900) tons
per year. Specific elements of the project include the following: (1) Conservation easement
acquisition. (2) Sedimentation reduction through construction of active and passive
sedimentation basins. (3) Long-term and regular maintenance of basins and removal of
accumulated sediments.
2. Planning, design and implementation of a channel restoration project to re-establish the
channel geometry of approximately two -hundred seventy feet (270') of Corbett Creek (aka
Tally Ho Creek) (Reach 3), thereby increasing flow volumes and reducing storm flow water
surfaces. -Beginning at the 4' headcut at -station 18+60, a rock weir will be installed, armoring
the headcut and lessening the steep grade. Following upstream from the rock weir, a low
flow channel would be excavated through sediment that has built up over the years along
Reach 3. According to the Tally Ho Tech Memo, developed in tandem with the engineered
design plans (Appendix B), a low flow channel would be cut between stations 18+60 and
20+50 (Figure 1). The thalweg will be lowered approximately 3 feet at station 18+60 and
slightly less elsewhere, removing a total of approximately 120 cubic yards of material. After
sediment has been removed, engineered streambed material will be placed, creating a
defined and roughened channel bed along approximately 100 linear feet of stream channel.
Parallel Encapsulated Soil Lifts will be installed along approximately 75 linear feet of steam
channel, creating a defined thalweg and increased storm flow capacity. The project has more
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
E
r
u
benefit at lower flows with less benefit at higher flows and is expected to reduce 5 -year
water surfaces by 1.7 feet at Cross Section 18+60 and 10 -year water surfaces by 1.1 feet.
Implementation of the project would involve temporary dewatering of the creek channel
and diversion of flows around the site, direct removal of sediment from the channel using an
excavator and manual removal of riparian vegetation. Access to the work area would be
through the vacant parcel at 210 Tally Ho Road. The planning and design phase is occurring
between 2021 and 2023. Construction of the stream restoration is planned for September
2023 with funding from the Department of Water Resources (DWR) through the Urban
Streams Restoration Program.
Figure 1. Existing conditions at Reach 3
9. Surrounding Land Uses and Setting
The City of Arroyo Grande is located in the southwestern portion of San Luis Obispo County, and
the project site is located within the northeast section of the City of Arroyo Grande. The City is
5.45 square miles in size and is bounded by the Cities of Grover Beach and Pismo Beach to the
southwest and west, and to the unincorporated County to the north, east and south. U.S. 101
extends northwest and southeast through the middle of the City, and Highway 227 runs east
from U.S. 101 through the Village Area. Residential Rural and Suburban development
characterize unincorporated areas to the north and southeast, and Agricultural uses dominate
the Arroyo Grande Valley that extends northeast and south of the City.
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
9
Cross-section at R5 14+06
ReacIp 3
EXISTING
CONDITIONS
REACH 3
2D -year flood elevation (788 ch)
1 D yr (898 df )
5 -yr (173 tfs)
z-
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Figure 1. Existing conditions at Reach 3
9. Surrounding Land Uses and Setting
The City of Arroyo Grande is located in the southwestern portion of San Luis Obispo County, and
the project site is located within the northeast section of the City of Arroyo Grande. The City is
5.45 square miles in size and is bounded by the Cities of Grover Beach and Pismo Beach to the
southwest and west, and to the unincorporated County to the north, east and south. U.S. 101
extends northwest and southeast through the middle of the City, and Highway 227 runs east
from U.S. 101 through the Village Area. Residential Rural and Suburban development
characterize unincorporated areas to the north and southeast, and Agricultural uses dominate
the Arroyo Grande Valley that extends northeast and south of the City.
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
9
from November to March. Corbett Creek stream flows remain elevated in the spring as
groundwater and subsurface flows contribute to the stream. The subwatershed is dominated by
agriculture and rural residential land uses. At the project reach the channel is not formally
channelized; however, encroachment activities by residents over the years have effectively
channelized portions of the creek. Vegetation within the project area includes native and exotic
grasses, native and exotic brush including blackberry and Willow trees, and ornamental
landscaping on the residential properties.
10. Required Approvals
California Department of Fish and Wildlife
Regional Water Quality Control Board
US Fish and Wildlife Service
US Army Corps of Engineers
11. California Native American Tribal Consultation (AB 52)
The 2013 MND was adopted prior to the incorporation of AB 52, which assesses a project's
impacts to Tribal cultural resources, into the CEQA Guidelines checklist. In the process of
developing this addendum, CSLRCD has integrated an assessment of tribal cultural resources into
the review process. Pursuant to AB52, CSLRCD contacted local Native American Tribes to notify
them of the project. In response to notification, several Tribal representatives responded
requesting formal consultation on the project. CSLRCD initiated formal consultation on April
14th, 2023. The outcomes of that consultation are detailed below in the Potential Impacts of
Revised Project section.
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
11
Potential Impacts of Revised Project
This addendum evaluates potential environmental impacts that could result from the updated project.
Appendix G of the CEQA Guidelines provides a checklist of environmental issues areas that are suggested
as the issue areas that should be assessed in CEQA analyses. The 2013 MND for the approved project
addressed 5 of the listed 24 environmental issue areas, including Biological resources, Cultural
Resources, Air Quality, Hydrology and Water quality, and Noise. The City of Arroyo Grande determined
that the approved project would not significantly impact the other issue areas, including Aesthetics,
Agricultural Resources, Geology and Soils, Greenhouse Gas Emissions, Hazards and Hazardous Materials,
Land use and Planning, Mineral resources, Population and Housing, Public Services, Recreation,
Transportation and Traffic, or Utilities. This addendum tiers off the 2013 MND, addresses the
environmental consequences of the updated project, focusing on Air Quality, Biological Resources, Tribal
Cultural Resources, Energy, Hydrology and Water Quality, and Noise, and updates the analysis for these
environmental issue areas based on current conditions, as listed below.
The potential environmental impacts of the updated project are considered in comparison with the
approved project, to determine whether impacts associated with the updated project are consistent
with the impact analysis provided in the 2013 MND for the approved Project, and whether additional
mitigation measures are required to minimize or avoid potential impacts.
Air Quality: The 2013 MND determined that emissions associated with project construction were less
than significant with mitigation. The scope of the updated project has not been modified to the
extent that emissions would increase. Therefore, the updated project would not result in new or
substantially more severe impacts associated with construction -related emissions when compared
to the analysis of the approved Project in the 2013 MND. Prescribed mitigation measures will be
implemented.
Bioloeical Resources: The 2013 MND determined that impacts to biological resources were less than
significant with mitigation due to the historical land used and modification as well as prevalence of
invasive species present. lt'is'still expected that the long term benefits of restoring the floodplain
and riparian habitat will outweigh short term impacts. The increased detail in the 65% engineered
design plans described construction activities more acutely, including the extent of grading, fill
volumes, and number of trees removed. This increased detail indicates that the updated project
will not result in new or substantially more impacts to sensitive species and habitats. Prescribed
mitigation measures will be implemented, and additional opportunities for on-site habitat
enhancement will be explored.
Tribal and Cultural Resources: As described above, additional Tribal Cultural Resource assessment
was completed in the development of this addendum to ensure the project's potential impacts to
Tribal resources was thoroughly assessed. Local Tribes were provided with a project description of
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
Fri
ground disturbing activities, engineered design plans, and a list of the avoidance and mitigation
measures incorporated into the 2013 MND for the protection of archaeological resources. During
formal the consultation process the following terms and conditions were agreed to:
- An approved archaeologist will conduct a California Historic Records Search for the
project area and provide a memo report presenting their assessment of potential project
impacts and recommendations for additional measures to protect Tribal resources
- A pedestrian survey of the project area will be conducted by an approved archaeologist
and Tribal representative prior to initiating any project activities.
- A Tribal monitor or approved archaeologist may choose to be present during ground
disturbing activities to monitor for the presence of Tribal resources.
- All previously adopted measures for the protection of cultural resources will be
implemented.
With the inclusion of these additional measures, the updated project will not result in new or
substantially more impacts to Tribal and Cultural Resources when compared to the analysis of the
approved Project in the 2013 MND.
Fns Energy as a resource issue was not analyzed in the 2013 MND. The project occupies a
relatively small footprint, utilizing an adjacent staging area and access route. Gas -powered
equipment will be used to execute the construction activities, and language will be included in
contracts that equipment must be maintained in good working order. Renewable energy will be
utilized as available for equipment. Due to the small footprint of the project and short construction
timeline, and requirements for equipment functionality, the updated project will not result in
potentially significant environmental impact or conflict with or obstruct a state or local plan for
renewable energy or energy efficiency when compared to the analysis of the approved Project in
the 2013 MND.
Hydrology/Water Quality: The 2013 MND determined that project activities, including grading and
filling, could degrade or violate water quality and waste discharge requirements, or alter existing
drainage patterns resulting in erosion or flooding. Analysis also determined that the project had the
potential to impede or redirect flood flows within a 100 -year flood hazard area and expose people or
structures to -a significant risk of loss, injury, or death from flooding. The increased detail in the 2022
65% engineered design plans describe construction activities more specifically, including the extent
of grading, fill volumes, and number of trees removed. Additionally, project proponents have
incorporated regulatory responses on required and recommended measures and modifications to
ensure the project activities are protective of water quality and will not increase flood elevations.
Approvals and permits include 401 Water Quality Certification for Small Habitat Restoration Projects
from the State Water Resources Control Board and a Flood Hazard Review from the City of Arroyo
Grande. Additional modeling of flood elevations via HEC -RAS modeling, indicating increased channel
capacity for storm flows and increased surface water elevations has been completed and is
incorporated in the 65% design plans and Tally Ho Technical Memo. Therefore, the updated project
would not result in new or substantially more severe impacts associated with water quality or
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
13
flooding when compared to the analysis of the approved Project in the 2013 MND. Adopted
mitigation measures will be implemented, including adoption of a project -specific Stormwater
Pollution Prevention Plan, establishment of permanent vegetation cover after project completion,
installation of erosion control practices during and following construction, and compliance with any
and all applicable regulation associated with floodway management.
is • The 2013 MND determined that sensitive receptors adjacent to the project area may be
exposed to noise levels in excess of established standards and that the project may generate periodic
or temporary increases in ambient noise levels, however impacts would be less than significant with
mitigation. The updated project would not result in an increase or change in the amount of noise
associated with the project. Therefore, the updated project would not result in new or substantially
more severe impacts associated with construction -related noise when compared to the analysis of
the approved Project in the 2013 MND. Adopted mitigation measures will be implemented.
Determination
In accordance with Section 15164 of the CEQA Guidelines, CSLRCD has determined this Addendum to the
2013 Corbett Creek Floodplain and Creek Restoration Project MND is necessary to document changes or
additions that have occurred in the project description since the 2013 MND was originally prepared. No
new or more severe environmental impacts beyond those disclosed in the 2013 MND would occur as a
result of the updated project. CSLRCD has reviewed and considered the information contained in this
Addendum in its consideration of the 2013 MND and finds the preparation of a subsequent CEQ4
Document is not necessary.
Neil Havlik, President, CSLRCD Board of Directors
Jac ' Crabb, CSLRCD Executive Director
Date
Date
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
14
References
Arroyo Grande Creek Erosion, Sedimentation and Flooding Alternatives Study, Swanson
Hydrology & Geomorphology, January 4, 2006
Tally Ho Tech Memo, Waterways Consulting, Inc, 2012
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
15
Appendix A: 50% designs for Sediment Basin
and Wetland Creation Project
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
16
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Appendix B: 65% designs for Stream Channel
Restoration
Addendum to the MND
Corbett Creek Floodplain and Stream Restoration Project
18
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