HomeMy WebLinkAboutItem 5b. GENP-0553-2022 General Plan Conformity Report for the Mid-Higuera Bypass Project
PLANNING COMMISSION AGENDA REPORT
SUBJECT: GENERAL PLAN CONFORMITY REPORT FOR THE ACQUISITION OF
EASEMENTS REQUIRED FOR THE MID-HIGUERA BYPASS PROJECT
BY: Shelsie Moore, Supervising Civil Engineer FROM: Tyler Corey, Deputy Director
Phone Number: (805)783-7735 Phone Number: (805)781-7169
Email: smoore@slocity.org Email: tcorey@slocity.org
APPLICANT: City of San Luis Obispo REPRESENTATIVE: Shelsie Moore
RECOMMENDATION
Adopt a Draft Resolution determining General Plan Conformance for the acquisition of
permanent and temporary easements required to complete the Mid -Higuera Bypass
Project (GENP-0553-2022).
1.0 COMMISSION'S PURVIEW
Section 65402 of the California Government Code requires the local planning agency
make a finding of General Plan conformance whenever a governmental entity proposes
to acquire or dispose of a property. Specifically, Section 65402 requires that the location,
purpose, and extent of real property acquisition (and disposition) be submitted to and
reported upon by the planning agency having jurisdiction as to conformity with the City’s
adopted general plan (Cal. Gov’t Code § 65402(c)).
2.0 SUMMARY
San Luis Obispo has experienced catastrophic flooding due to the nature of its watershed.
Most recently, in 1995, flooding caused damage throughout the San Luis Obispo
watershed, with creeks breaching their banks and creek bank failures. In response to the
damage, and to protect residents, businesses, and infrastructure, the Ci ty requested
permits from regulatory agencies to repair the damage to public facilities. The Army Corps
of Engineers and other regulators requested the City prepare a comprehensive Waterway
Management Plan (WMP) that could be used as the basis for future project planning,
decision making, and permitting.
The Waterway Management Plan (WMP) preparation was approved by Council in the fall
of 1999. In January 2002, the WMP was presented to Council and direction was received
for various aspects of the program, which included flood protection levels, major capital
projects, and design policies. On October 21, 2003, Council adopted the WMP, a thre e-
volume document, which includes components for stream management and
maintenance, a drainage design, and a flood management plan identifying potential flood
management projects.
Meeting Date: 10/26/2022
Item Number: 3b
Time Estimate: N/A - Consent
Page 9 of 126
Item 3b
GENP-0553-2022
Planning Commission Report – 10/26/2022
Mid-Higuera Bypass Project
The Mid-Higuera Bypass Project is the highest priority project identified in the WMP and
is located along the stretch of the San Luis Obispo Creek between Marsh Street and
Madonna Road (See Figure 1). This project will increase flood protection by removing
sediment and creek vegetation overgrowth, creating pathways for flood waters to return
to the creek, creating flood bypass channels within City open space, widening narrow
sections of creek for increased capacity, and replacing the existing Bianchi Lane Bridge
with a larger span bridge in order to widen the creek and increase flow capacity at that
location.
Figure 1: Mid-Higuera Bypass Project Location
The County Flood Control and Water Conservation District Zone 9 Advisory Committee
(Zone 9) with contributing oversight from staff and members of the public from both the
City and County, oversees implementation of projects recommended in the WMP. Since
Zone 9 initially approved County funding for planning and design work on the Mid-Higuera
Bypass project, a feasibility study, a Final Supplemental Environmental Impact Report
(Final SEIR), and 90% level plans and specifications have been completed. The City is
coordinating with County of San Luis Obispo staff on environmental permit s for project
construction.
Page 10 of 126
Item 3b
GENP-0553-2022
Planning Commission Report – 10/26/2022
The next step is for the City to coordinate with adjacent property owners for areas where
the creek work impacts private property. There are 25 properties adjacent to the project
limits including six parcels that are owned by the City. The majority of the work is within
the City owned parcels, but some work will be required on private property. The City plans
to work with adjacent property owners to secure temporary and permanent easements to
complete the work.
Staff have identified seven properties that will require permanent and temporary
construction easements in order to construct the project improvements. These permanent
easements will be for creek channel widening work including widening necessary for the
replacement of Bianchi Lane Bridge and associated infrastructure and utilities. There are
twelve properties that will only need temporary construction easements , which are
necessary for creek cleanup, vegetation removal, new plantings, and temporary irrigation.
The parcels requiring easements are identified in Attachment B. The specific easement
boundaries will vary by parcel and are not yet identified at this time.
3.0 PREVIOUS REVIEW
On April 28, 2021, the Planning Commission reviewed and approved the Capital
Improvement Plan of the 2021-23 Financial Plan for General Plan Conformity, which
included Mid-Higuera Bypass (row 280), but the location, purpose, and extent of the
necessary easement acquisition was not specifically provided. Additionally, on May 25,
2022, the Planning Commission reviewed and approved the Capital Improvement Plan
from the FY 22-23 Budget Supplement for General Plan Conformity.
4.0 PROJECT ANALYSIS
The Mid-Higuera Bypass Project was listed under conformance with the Safety Element
during the review of the 2021-23 Capital Improvement Plan. Specifically, the project is in
compliance with the Safety Element 2.1 Policy S: Flood Hazard Avoidance and Reduc tion
Item B:
The City should allow flood waters to move through natural channels. Flow
should be accommodated by removing debris and man -made obstructions.
The City recognized that many natural channels cannot contain runoff from
a storm greater than a 25-year event. Areas flooded by storms as large as
a 100-year event will be mapped.
The Mid-Higuera Bypass project including all easements needed to complete the work is
in compliance with the Safety Element listed above. Staff recommends finding General
Plan Conformity for any easement needed along the project limits to complete the project.
The proposed temporary and permanent easements will fulfill the City’s Safety Element
Policy and help achieve the Safety Goal of minimizing damage to public and priva te
property due to flooding.
Page 11 of 126
Item 3b
GENP-0553-2022
Planning Commission Report – 10/26/2022
5.0 ENVIRONMENTAL REVIEW
A Final Supplemental Environmental Impact Report (SEIR) (Attachment C) was prepared
by County Staff for the project focusing on the following mitigations: biological resources,
cultural resources, air quality, visual resources, hazardous materials, drainage/erosion
and sedimentation, and noise. On August 21, 2018, San Luis Obispo County Board of
Supervisors certified the SEIR. SEIR State Clearinghouse Number is SCH2016021077.
In accordance with recommendations of the SEIR, County Staff are applying for permits
with the Water Resources Control Board, California Fish and Wildlife, and Army Corp of
Engineers.
6.0 OTHER DEPARTMENT COMMENTS
There is concurrence from the Administration and Utilities Departments on this project.
7.0 ALTERNATIVES
1. Continue consideration of the proposal, with direction to staff on items needed or
necessary information to make a decision on General Plan conformity.
2. Deny that the proposed easement acquisitions for the Mid-Higuera Bypass Project
are in conformance with the General Plan based on finding(s) of inconsistency with
the General Plan. Staff does not recommend this alternative as the project is a
critical safety improvement for flooding in the Mid-Higuera area.
8.0 ATTACHMENTS
A - Draft Planning Commission Resolution determining General Plan Conformance for
the acquisition of easements for the Mid-Higuera Bypass Project
B - Exhibit A to Draft Resolution - Mid-Higuera Bypass Parcels
C - Final Supplemental Environmental Impact Report (SEIR) without Appendices
Page 12 of 126
R ______
RESOLUTION NO. PC-XXXX-22
A RESOLUTION OF THE PLANNING COMMISSION OF THE CITY OF
SAN LUIS OBISPO, CALIFORNIA, DETERMINING GENERAL PLAN
CONFORMANCE FOR THE ACQUISITION OF PERMANENT AND
TEMPORARY EASEMENTS REQUIRED TO COMPLETE THE MID-
HIGUERA BYPASS PROJECT, AS REPRESENTED IN THE STAFF
REPORT AND ATTACHMENTS DATED OCTOBER 26, 2022 (GENP-
0553-2022)
WHEREAS, the Planning Commission of the City of San Luis Obispo conducted a public
meeting in the Council Chamber of City Hall, 990 Palm Street, San Luis Obispo, California, on
October 26, 2022, for the purpose of reviewing acquisitions of easements necessary for the Mid-
Higuera Bypass project for General Plan Conformity as required by California Government Code
Section 65402 (GENP-0553-2022); and
WHEREAS, notices of said public meeting were made at the time and in the manner
required by law; and
WHEREAS, the Planning Commission has duly considered all evidence and
recommendations by staff as presented in the staff report.
NOW, THEREFORE, BE IT RESOLVED by the Planning Commission of the City of
San Luis Obispo as follows:
SECTION 1. Findings. Based upon all the evidence, the Commission makes the
following findings:
1. The acquisition of easements for the Mid-Higuera Bypass Project will not harm the
general health, safety, and welfare of people living or working in the vicinity because
the proposed project is consistent with the General Plan Safety Element. The parcels
requiring easements are identified in Exhibit A. The specific easement boundaries will
vary by parcel and are not yet identified at this time.
SECTION 2. Environmental Review. A Final Supplemental Environmental Impact Report
(SEIR) was prepared by County Staff for the project focusing on the following mitigations:
biological resources, cultural resources, air quality, visual resources, hazardous materials,
drainage/erosion and sedimentation, and noise. On August 21, 2018, San Luis Obispo County
Board of Supervisors certified the SEIR. SEIR State Clearinghouse Number is SCH2016021077.
Page 13 of 126
PC Resolution No. _____ (2022 Series) Page 2
R _____
SECTION 3. Action. The Planning Commission does find and report that GENP-0553-
2022 conforms to the City of San Luis Obispo’s General Plan pursuant to California Government
Code Section 65402.
Upon motion of _______________________, seconded by _______________________,
and on the following roll call vote:
AYES:
NOES:
ABSENT:
The foregoing resolution was adopted this _____ day of _____________________ 2022.
____________________________________
Tyler Corey, Secretary
Planning Commission
Page 14 of 126
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Page 16 of 126
FINAL
SUPPLEMENTAL ENVIRONMENTAL IMPACT REPORT
FOR THE MID-HIGUERA BYPASS PROJECT
SCH# 2016021077
Prepared By:
San Luis Obispo County Flood Control and
Water Conservation District
County Government Center, Room 200
San Luis Obispo, CA 93408
August 2017
Page 17 of 126
FINAL
Supplemental Environmental Impact Report
for the
Mid-Higuera Bypass Project
SCH# 2016021077
Prepared By:
San Luis Obispo County Flood Control and
Water Conservation District
County Government Center, Room 200
San Luis Obispo, CA 93408
August 2017
Page 18 of 126
Executive Summary
ES-1 Mid-Higuera Bypass Project FSEIR
Executive Summary
Purpose of the EIR
The purpose of an Environmental Impact Report (EIR) is to provide State and local agencies as
well as the general public with detailed information on the potentially significant environmental
effects which a proposed project is likely to have, to list ways which the significant
environmental effects may be minimized, and indicate alternatives to the project. This
Supplemental Environmental Impact Report (SEIR) addresses the environmental effects of the
construction and operation of the Mid-Higuera Bypass Project (project). The information
presented here supplements the October, 2003 San Luis Obispo Creek Watershed Waterway
Management Plan Final Programmatic Environmental Impact Report/Environmental Impact
Statement (EIR/EIS).
This SEIR has been prepared in accordance with the California Environmental Quality Act
(CEQA) as amended, and the latest State Guidelines for the Implementation of CEQA. The
need for a SEIR is justified based upon the review of project-specific design, the completion of
project-specific technical reports, and the completion of an Initial Study for the project (refer to
Appendix A).
Project Location
The project is located within and adjacent to San Luis Obispo Creek between the Marsh Street
Bridge (upstream) and Madonna Road Bridge (downstream). It is bordered on the west by
Highway 101 and on the east by Higuera Street. It is located completely within the City of San
Luis Obispo (refer to the Vicinity Map, Site Map, and Appendix B).
Project Background
The Mid-Higuera Bypass Project was specifically discussed in the EIR/EIS as one of five Capital
Improvement Projects; however, it was determined that subsequent environmental review would
be required at such time as project-specific data was available for review.
Proposed Project
The Mid-Higuera Bypass Project (project) is proposed to increase the flood control capacity of
San Luis Obispo Creek (creek) between Marsh Street and Madonna Road due to the following
concerns:
x there is currently less than 25-year storm capacity in this stretch of the creek;
x significant bank erosion exists in some locations;
x there is localized sediment accumulation, particularly at the Marsh Street Bridge;
x a poor pool-to-riffle ratio exists;
x substantial invasive species and exotic plants are present; and
x there is a lack of continuity and/or diversity in native riparian vegetation.
Page 19 of 126
Executive Summary
ES-2 Mid-Higuera Bypass Project FSEIR
Vicinity Map
Page 20 of 126
Executive Summary
ES-3 Mid-Higuera Bypass Project FSEIR
Site Map
Page 21 of 126
Executive Summary
ES-4 Mid-Higuera Bypass Project FSEIR
The proposed project includes five components developed to directly address these issues,
including:
Bypass Channels. The project would include the construction of two bypass channels, the
Bianchi Bypass and the South Street Bypass. The bypass channels are proposed between the
creek and Highway 101. They have been designed to be active during larger storm events (i.e.,
they are designed to be “above” the Ordinary High Water Mark [OHWM] of the creek), and to
flow full during 25-year storm events. Vegetated rock slope protection as well as root wads/flow
deflectors would be installed at both the upstream and downstream transition areas between the
bypass channels and the creek.
Benches and Related Grading. In addition to the bypass channels, the capacity and functionality
of the creek channel would be expanded through the construction of four benches, by laying
back slopes at the “pinch point”, and through construction of a “flow return”. Similar to the
bypass channels, the four benches proposed would be excavated above the creek OHWM and
would reach approximately 20-30 feet wide. The maximum slopes above the benches would be
excavated no steeper than 2.5:1.
Marsh Street Sediment Removal. Significant sediment has accumulated on the upstream side of
the Marsh Street Bridge and within the three bridge barrels. Further, the upstream sediment has
formed an island that is blocking the largest center barrel. To address this issue, sediment will
be removed upstream of the bridge, within the bridge barrels, and downstream of the bridge.
The sediment would be removed to 1-foot above the creek water surface elevation at time of
construction. This strategy will preserve the existing low flow channel through the bridge. In
addition, the western bank will be sloped back to a 2.5:1 slope.
Bianchi Lane Bridge Replacement. The existing Bianchi Lane Bridge is an old bridge that was
relocated to its current position many years ago. It is relatively low and narrow, and as a result
can only accommodate flows from a 6-year storm event. The proposed new bridge will be a two-
span bridge with a higher deck elevation and will incorporate the start of the first bypass
channel. The new bridge will provide capacity for an approximately 23-year storm event. The
new bridge installation will include grading to accommodate the new road approaches.
Riparian Enhancement. Riparian enhancements have been incorporated for each of the
components described above. Vegetated rock slope protection would be installed at the
confluence of the creek channel and the bypass channels. At these locations, root wads would
also be installed to provide pools and habitat complexity to the creek. At the Bianchi Bypass
downstream transition area, rock flow deflectors will be installed to create pools and hydrologic
complexity.
Notice of Preparation
In accordance with the provisions of the State CEQA Guidelines, a Notice of Preparation (NOP)
for the project was distributed on February 19, 2016. The advertised comment period ended on
March 21, 2016. A total of five responses, including one from the State Clearinghouse, were
received. These responses are included in Appendix A.
Page 22 of 126
Executive Summary
ES-5 Mid-Higuera Bypass Project FSEIR
Draft Supplemental Environmental Impact Report
The Draft Environmental Impact Report (DSEIR) was released for public comment on
September 23, 2016 for a 45-day public review period. The review period closed on November
7, 2016. The District received four comment letters, three from public agencies, and one from a
member of the public. Appendix E of the Final EIR describes persons, organizations, and public
agencies commenting on the DSEIR; verbatim comments received through the EIR process;
and responses by the lead agency to comments received. The comments did not result in any
significant new information or substantial revisions to the DSEIR.
Significant Environmental Impacts Identified
Table ES-1 shows each impact identified and all mitigation measures recommended to reduce
or avoid impacts. The most significant potential impacts identified in this EIR include:
Aesthetic Resources. The project proposes to revegetate the site after construction, although it
may take 5-10 years or more before the vegetation provides the screening of urban uses from
Highway 101 as it currently does.
Biological Resources. These impacts would include Impacts to the San Luis Obispo Creek
riparian corridor from construction, including temporary dewatering, tree and vegetation
removal, impacts to special-status wildlife species, and the potential to result in erosion and
sedimentation of the creek.
Hazards and Hazardous Materials. Hazardous materials have been identified within the project
corridor and they are likely to be encountered during construction of the project.
All impacts identified in the EIR can be reduced to a level of insignificance with mitigation.
Project Alternatives
Despite the fact that the 2003 EIR/EIS considered a reasonable range of alternatives to the Mid-
Higuera Bypass project specifically, Chapter 6 of the SEIR includes discussion of additional
alternatives in an attempt to reduce the severity of the short-term construction-related impacts
identified. These alternatives include:
1. Land Purchase/Business Relocation - Purchasing the properties along Higuera Street
most vulnerable to flooding, thereby reducing the flood risk;
2. Marsh Street Bridge Replacement - Reconstructing the Marsh Street Bridge and
Highway 101 interchange;
3. No Project Alternative – This alternative is required by CEQA, and in this case would
include periodic maintenance of the creek reach, including the vegetation and sediment
management that is already periodically performed by the County; and
4. Phased Project – Phasing construction over multiple years to reduce short-term
construction-related impacts to noise, air quality and traffic, as well as to minimize
disturbance to biological resources within the creek channel in any single year.
The alternatives analysis concludes that the proposed project with all mitigation applied may be
the environmentally superior alternative, or at least be the environmentally equivalent of the
phased project alternative.
Page 23 of 126
Executive Summary
ES-6 Mid-Higuera Bypass Project FSEIR
Impact Summary Table
The table on the following pages provides a summary of the potential impacts of the proposed
project. Also summarized in these tables are the mitigation measures associated with each
impact that are to be implemented by the project applicant in order to reduce the environmental
impacts to a level of insignificance. In accordance with CEQA, the Summary Table identifies the
types of potential impacts described in EIRs and those specifically associated with the proposed
development.
Class I Impacts—Significant environmental impacts that cannot be fully mitigated or avoided.
The decision maker must adopt a “Statement of Overriding Considerations” as required under
CEQA Guidelines Section 15093 if the project is approved. No Class I impacts have been
identified.
Class II Impacts—Significant environmental impacts that can be feasibly mitigated or avoided.
The decision maker must issue “Findings” under CEQA Guidelines §15091(a) if the project is
approved. All Class II impacts identified are described in the table below.
Class III Impacts—Environmental impacts that are adverse but not significant for which the
decision maker does not have to adopt “Findings” under CEQA. All Class II impacts identified in
this EIR would become Class III impacts with the adoption of the recommended mitigation.
Class IV Effect—An effect that would be beneficial, and would reduce existing environmental
impacts or hazards. The proposed project would potentially have beneficial impacts to water
resources because it would result in the removal of potentially hazardous soils and decrease the
risk of flooding; however, these potentially beneficial impacts are not specifically described in
the tables below.
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Executive Summary ES-7 Mid-Higuera Bypass Project Final SEIR Table ES-1 Potentially Significant Impacts that can be Feasibly Mitigated (Class II Impacts) Impact Duration Recommended Mitigation Measures Impact Class after Mitigation Applied Aesthetic Resources AR Impact 1 The project would cause a noticeable change to the visual environment of the site and its surroundings due to a loss of vegetative character, visibility of engineered channels and slope protection, and increased visibility to the development along Higuera Street, South Street and the Caltrans building north of Madonna Road as seen from Highway 101. Short and medium-term AR-mm-1 Prior to initiation of the project, the District shall ensure that revised grading and site plans show the following: 1. All channel benches and bypass channels shall employ contour grading design and construction techniques to reduce their engineered appearance. All grade breaks shall be rounded and avoid angular slope-interface. 2. All top-of-slope hinge-points shall employ slope-rounding where doing so would not adversely affect existing vegetation. Class III AR-mm-2 Prior to initiation of the project, the District shall ensure preparation and implementation of a planting plan, which shall supplement the Vegetation Enhancement Plan, be developed and signed by a licensed landscape architect or restoration specialist, and include the following: 1. Visual screen planting between the easternmost extent of channel and bench grading and the adjacent parcels east of the project, between Stations 13+50 and 17+00, and between Stations 22+50 and 27+00. 2. Screen planting shall be a mix of evergreen trees and shrubs placed in natural-looking patterns. 3. Trees planted for screening along the fence shall be planted from primarily 24-inch box containers. Shrubs shall be planted from minimum 5-gallon containers. 4. Screen planting shall include the appropriate number and density of plants to achieve a minimum of 90 percent visual screening of the adjacent development as seen from Highway 101 within five years. 5. Additional planting between the bypass channels and the Highway 101 right-of-way, to the maximum extent possible. 6. Planting along Highway 101 shall be a mix of evergreen trees and shrubs placed in natural-looking patterns. 7. Trees planted along Highway 101 shall be planted from primarily 24-inch box containers. Shrubs shall be planted from minimum 5-gallon containers. AQ Impact 1 Project construction activities would result in emissions levels that exceed SLOAPCD thresholds. Short-term AQ-mm 1 A Construction Activity Management Plan (CAMP) shall be prepared for the proposed project. The CAMP shall be submitted to the SLOAPCD for review and approval prior to the start of construction. The CAMP shall include, at a minimum, the following elements: 1. Identification of the project construction schedules. To the extent possible, construction activities should be phased to minimize cumulative increases of daily emissions from multiple activities. 2. Identification of schedules for truck hauling activities and associated haul routes. Haul routes and schedules that would have the least impact to nearby sensitive receptors shall be selected. Construction activities and haul truck trips should be scheduled during non-peak hours (as determined by the Public Works Director) to reduce peak hour emissions. 3. Identification of construction-equipment permitting requirements. Portable equipment, 50 horsepower (hp) or greater, used during construction activities may require California statewide portable equipment registration (issued by the California Air Resources Board) or a SLOAPCD permit. Examples of such equipment may include, but are not limited to, standby generators, material processing equipment (e.g., crushers, conveyors, portable batch plants, tub grinders, trammel screens). 4. Identification of a designated person or persons responsible for implementation of the CAMP and emissions monitoring and compliance. The designated individual(s) shall be responsible for monitoring of fugitive dust emissions and the implementation/enhancement of measures, as necessary, to minimize dust complaints, reduce visible emissions below the Class III Page 25 of 126
Executive Summary ES-8 Mid-Higuera Bypass Project Final SEIR SLOAPCD’s limit of 20% opacity for greater than 3 minutes in any 60-minute period. Their duties shall include holidays and weekend periods when work may not be in progress. The name and telephone number of such persons shall be provided to the SLOAPCD Compliance Division prior to the start of any grading, earthwork or demolition. 5. Tabulation of on-road and off-road construction equipment. Emissions shall be quantified in accordance with SLOAPCD-recommended methodologies based on project-specific construction requirements (e.g., construction schedules, construction vehicle trips, and off-road equipment fleet to be used during project construction. 6. Identification of fugitive dust and mobile-source emission control measures to be implemented sufficient to demonstrate compliance with SLOAPCD’s CEQA thresholds of significance and to minimize nuisance impacts at nearby sensitive receptors. AQ Impact 2 The project could expose sensitive receptors to pollutants such as lead and fugitive dust. Short-term AQ-mm 2 The following measures shall be implemented during construction to reduce potential expose of sensitive receptors to substantial pollutant concentrations. These measures shall also be included in the CAMP to be prepared for this project 1. Demolition of onsite structures shall comply with the National Emission Standards for Hazardous Air Emissions (NESHAP) requirements (NESHAP, 40 CFR, Part 61, Subpart M) for the demolition of existing structures. The SLOAPCD is delegated authority by the Environmental Protection Agency (EPA) to implement the Federal Asbestos NESHAP. Prior to demolition of onsite structures, the SLOAPCD shall be notified, per NESHAP requirements. 2. If during demolition of Bianchi Lane Bridge, paint is separated from the construction materials (e.g. chemically or physically), the paint waste will be evaluated independently from the building material by a qualified hazardous materials inspector to determine its proper management. All hazardous materials shall be handled and disposed in accordance with local, state and federal regulations. 3. According to the Department of Toxic Substances Control (DTSC), if paint is not removed from the building material during demolition (and is not chipping or peeling), the material can be disposed of as construction debris (a non-hazardous waste). The landfill operator will be contacted prior to disposal of building material debris to determine any specific requirements the landfill may have regarding the disposal of lead-based paint materials. The disposal of demolition debris shall comply with any such requirements. 4. On-road diesel vehicles shall comply with Section 2485 of Title 13 of the California Code of Regulations. In general, the regulation specifies that drivers of said vehicles: x Shall not idle the vehicle’s primary diesel engine for greater than 5 minutes at any location, except as noted in Subsection (d) of the regulation; and, x Shall not operate a diesel-fueled auxiliary power system to power a heater, air conditioner, or any ancillary equipment on that vehicle during sleeping or resting in a sleeper berth for greater than 5.0 minutes at any location when within 1,000 feet of a restricted area, except as noted in Subsection (d) of the regulation. x Off-road diesel equipment shall comply with the 5-minute idling restriction identified in Section 2449(d)(2) of the California Air Resources Board’s In-Use off-Road Diesel regulation. x Signs must be posted in the designated queuing areas and job sites to remind drivers and operators of the state’s 5 minute idling limit. x Construction truck trips shall be scheduled, to the extent feasible, to occur during non-peak hours. x The burning of vegetative material shall be prohibited. 5. Should hydrocarbon contaminated soil be encountered during construction activities, the SLOAPCD shall be notified as soon as possible and no later than 48 hours after affected material is discovered to determine if a SLOAPCD Permit will be required. In addition, the following measures shall be implemented immediately after contaminated soil is discovered: x Covers on storage piles shall be maintained in place at all times in areas not actively involved in soil addition or removal; x Contaminated soil shall be covered with at least six inches of packed uncontaminated soil or other TPH –non-permeable barrier such as plastic tarp. No headspace shall be allowed where vapors could accumulate; x Covered piles shall be designed in such a way to eliminate erosion due to wind or water. No openings in the covers are permitted; x The air quality impacts from the excavation and haul trips associated with removing the contaminated soil must be Class III Page 26 of 126
Executive Summary ES-9 Mid-Higuera Bypass Project Final SEIR evaluated and mitigated if total emissions exceed the SLOAPCD’s construction phase thresholds; x During soil excavation, odors shall not be evident to such a degree as to cause a public nuisance; and, x Clean soil must be segregated from contaminated soil. BR-Impact 1 California red-legged frog may be directly impacted during construction activities. Short-term BR-mm 1 Through the USACE permit process, conduct consultation with the USFWS to develop avoidance and minimization measures for the CRLF. These measures may include, for example, the measures described in the 1999 CRLF Programmatic Biological Opinion between the USFWS and the USACE. Class III BR-Impact 2 South-central California coast steelhead may be directly impacted during construction activities. Short-term BR-mm 2 Construction requiring stream dewatering, stream crossings, or work in the channel bed will not start before June 1. Upstream and downstream passage for fish, including juvenile steelhead, will be provided through or around construction sites at all times. Cofferdams will be installed to divert streamflow around each in-stream construction area. Class III BR-mm 3 Through the USACE permit process, conduct consultation with the NMFS to develop avoidance and minimization measures for steelhead. These measures may include, for example, having a qualified biologist onsite during the installation of cofferdams and during the cofferdam dewatering process to capture and move trapped salmonids and other fish as well as identifying the appropriate procedures for relocating fish. Protocols for the capture, handling, and release of fish will be developed in cooperation with NMFS and CDFW and implemented during project construction. Class III BR-Impact 3 Implementation of the project would potentially result in long-term adverse impacts to the habitat value of the creek for steelhead within the project area. Long-term BR-mm 4 Prior to construction the project plans shall be revised to show the bypass channels sloped towards the “inside” bank to minimize the potential for ponding water. BR-mm 5 Prior to construction the project plans shall incorporate additional boulder clusters or similar features into the design of the transition areas. BR-mm 6 At the appropriate time following applicable storm events, the bypass channels shall be inspected to determine the potential for ponded water and to confirm no fish have been stranded. In the event that special-status fish are observed stranded in the bypass channels, they shall be relocated by a qualified biologist consistent with necessary permits and authorizations. BR-mm 7 Prior to construction and following construction at appropriate intervals, the habitat assessments consistent with those performed for the WMP shall be conducted by qualified biologists. These efforts shall be described in and coordinated with habitat restoration monitoring to be described in the HMMP for the project. BR-Impact 4 Removal of larger stands of eucalyptus within the project corridor would potentially impact overwintering monarch butterflies. Short-term BR-mm 8 To avoid impacts to monarch butterflies, construction shall be avoided as feasible during the monarch butterfly wintering period (November to February). However, if work is scheduled to occur during this time, the project corridor shall first be surveyed for overwintering monarch butterfly. If substantial monarch butterfly population is observed, tree removal shall cease within 200 feet of the population, and sufficient dust control measures shall be implemented to minimize dust emissions and associated impacts to any eucalyptus groves within or directly adjacent to project-related ground disturbance. Class III BR Impact 5 Demolition of the Bianchi Lane Bridge and tree removal would potentially impact roosting bats. Short-term BR-mm 9 Prior to construction, one daytime and one night-time pre-construction surveys shall be conducted by qualified biologists no more than 30 days prior to construction to determine if bats are day or night roosting in the project area. The biologist(s) conducting the preconstruction surveys will also identify the nature of the bat utilization of the area (i.e., no roosting, night roost, day roost, maternity roost). If bats are found to be roosting in the surveyed areas, the following measures will be implemented during construction: 1. If there is only night roosting by bats and the roost substrate will not be impacted, work may proceed as normal provided that no night-time work is scheduled. 2. If there is day roosting by bats (or night roosting and work during nighttime), qualified biologists shall monitor any construction activities within 100 ft for disturbance to bat roosting. If bat roosting behavior is determined to be adversely impacted by construction activities, construction must be avoided in the vicinity of bat roosts until either Class III Page 27 of 126
Executive Summary ES-10 Mid-Higuera Bypass Project Final SEIR bats are no longer roosting or they have been excluded from roosting. 3. If maternity roosts are detected, construction activities must be avoided within 100 ft (30 m) of an active maternity roost until the end of the maternity roosting season (end of September). No roost exclusion shall be conducted if maternity roosts are detected. 4. Readily visible exclusion zones shall be established in areas where roosts must be avoided. BR-mm 10 The design of the new Bianchi Lane Bridge shall incorporate bat friendly features and/or provide areas where manmade roosts can be easily attached during construction. If manmade roosts are to be attached to the bridge, this shall be accomplished prior to the conclusion of construction activities. BR Impact 6 Project construction will impact approximately 3.94 acres of riparian forest and riverine communities and result in the removal of approximately 128 native trees impacting the riparian habitat for wildlife. Short and medium term BR-mm 11 Prior to construction, the project proponent will retain a qualified biological monitor(s) to monitor construction and ensure compliance with Avoidance and Minimization Measures within the project environmental documents. Class III BR-mm 12 Before any activities begin on a project, a qualified biologist shall conduct a training session for all construction personnel. At a minimum, the training shall include a description of the important vegetation and special-status resources that occur in the project area, the specific measures that are being implemented to conserve them and the boundaries within which the project may be accomplished. Brochures, books, and briefings may be used in the training session, provided that a qualified person is on hand to answer any questions. BR-mm 13 During construction, work within the creek shall be conducted when the creek does not contain flowing or standing water, if feasible. If work activities must occur when water is present in the creek channel, the contractor shall dewater the creek prior to conducting the activities. BR-mm 14 Prior to any construction work beginning, including any vegetation clearing, sturdy high visibility fencing shall be installed to protect jurisdictional areas and sensitive resource areas adjacent to the work area. This fencing shall be placed so that unnecessary impacts to adjacent habitat are avoided. No construction work (including storage of materials) shall occur outside of the “Project Limits”. The required fencing shall remain in place during the entire construction period and maintained as needed by the contractor. BR-mm 15 During construction, the cleaning and refueling of equipment and vehicles will occur only within a designated staging area and as far from aquatic areas as feasible. At a minimum, all equipment and vehicles will be checked and maintained on a daily basis to ensure proper operation and avoid potential leaks or spills. BR-mm 16 During construction, the biological monitor(s) will ensure that the spread or introduction of invasive exotic plant species is avoided to the maximum extent possible. When practicable, invasive exotic plants in the project site will be removed and properly disposed. BR-mm 17 During construction, trash will be contained, removed from the work site, and disposed of regularly. Following construction, all trash and construction debris will be removed from work areas. All vegetation removed from the construction site shall be taken to a certified landfill to prevent the spread of invasive species. BR-mm 18 During construction, no pets will be allowed on the construction site. Page 28 of 126
Executive Summary ES-11 Mid-Higuera Bypass Project Final SEIR BR-mm 19 Prior to construction, a comprehensive Habitat Mitigation and Monitoring Plan (HMMP) shall be prepared that reflects the guidance of the WMP and includes the following guidelines: 1. Results in an improved pool to riffle ratio, reduction in invasive species, and increase of canopy cover provided by native species for Reach 10 compared to the 2002 assessment. 2. A 1:1 replacement ratio for temporary impacts to riverine and riparian vegetation communities. 3. A 2:1 replacement ratio for permanent impacts to riverine and riparian communities. 4. A replacement ratio for native trees and shrubs impacted by the project that will result in equal to or better habitat conditions within the project corridor as quickly as feasible. 5. Considers invasive species and debris removal in-lieu of a strict tree replacement ratio where appropriate 6. Allows for flexibility in species to be planted so that predominately single-trunk species such as black walnut, black cottonwood, and bay laurel can be substituted for willows, for example. 7. Takes advantage of the bypass channels and terraces between the bypass channels and the creek to replace the ruderal and nonnative annual grassland vegetation communities with riparian and upland ones, even in areas not directly impacted by the project construction. BR-mm 20 During construction, the project will make all reasonable efforts to limit the use of imported rock. Imported material should be obtained from a source that is known to be free of invasive plant species; or the material must consist of purchased clean material such as crushed aggregate, sorted rock, or similar. BR-Impact 7 Construction activities would result in impacts to nesting avian species Short and medium term BR-mm 21 To protect special-status avian species and those species protected by the MBTA, the District shall avoid vegetation clearing and earth disturbance during the typical nesting season (February 15 to September 1). If avoiding construction during this season is not feasible, a qualified biologist shall survey the area within one week prior to activity beginning on site. If nesting birds are located on or near the proposed project site, they shall be avoided until they have successfully fledged. A buffer zone of 50 feet will be placed around all non-sensitive, passerine bird species, and a 250-foot buffer will be implemented for raptor species, and all activity will remain outside of that buffer until the qualified biologist has determined that the young have fledged. Buffer reductions and/or work within non-disturbance buffer areas can be completed only with approval from relevant resource agencies. Class III CR Impact 1 Excavation of the project components, including, but not limited to the Flow Return, the Pinch Point, and the Bypass channels, have the potential to impact buried historical resources. Short-term CR-mm-1 Prior to construction, a detailed excavation and monitoring plan shall be prepared and implemented by a qualified historical archaeologist. The monitoring plan shall specify the following: 1. A description of preconstruction exploratory excavations at the Flow Return; 2. A description of how and where the monitoring will occur; 3. Description of monitoring intensity at different project locations; 4. A description of the resources anticipated to be discovered; 5. A description of the circumstances under which construction will be halted; 6. Description of the procedures to be followed in the event significant resources are found; 7. Personnel involved in monitoring activities; and 8. Arrangements for curation and a description of those materials that would qualify for curation. 9. Procedures to be implemented in the event there is an unanticipated historical or prehistoric discovered within the project area during construction to ensure compliance with State and local code. Class III HAZ Impact 1 During excavation of the project components construction personnel and the local environment may be exposed to hazardous materials that exist in the soils. Short-term Haz-mm-1 Prior to initiation of construction, the District shall submit to the City of San Luis Obispo Fire Department, a Construction Materials Management Plan (CMMP). The CMMP plan shall be implemented throughout construction. The CMMP shall at minimum present an overview of the procedures and protocols that will be utilized during the project to safely and appropriately recover, handle, characterize, store, transport, and dispose of any contaminated materials encountered during construction of the project. In the event that hazardous materials are encountered during excavation activities, the Class III Page 29 of 126
Executive Summary ES-12 Mid-Higuera Bypass Project Final SEIR contaminated soil shall be excavated to the extent necessary to safely construct the project. HWQ-Impact 1 The Flow Return would potentially concentrate polluted flood water and discharge it to the creek system with no treatment. Short-term HWQ-mm-1 Prior to construction, to minimize the potential for concentrating pollutants at the Flow Return where flood waters would re-enter San Luis Obispo Creek, this component shall be designed to maximize the potential for passive storm water treatment. Class III NS-Impact 1 Night-time or weekend construction would potentially significantly impact sensitive receptors in the project area. Short-term NS-mm 1 To reduce potential noise impacts, the following measures shall be implemented during construction: x Noise-generating construction activities shall be limited to between the hours of 7:00 a.m. and 7:00 p.m., Monday through Saturday. x Noise-generating construction activities shall be prohibited on Sundays and holidays. x Construction equipment shall be properly maintained and equipped with noise-reduction intakes and exhaust mufflers and engine shrouds, in accordance with manufacturers’ recommendations. x Equipment engine shrouds shall be closed during equipment operation. x Lay-down yards and semi-stationary equipment such as pumps or generators shall be located at the furthest practical distance from noise-sensitive land uses. Class III Page 30 of 126
Table of Contents
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Mid-Higuera Bypass Project FSEIR
Table of Contents
Chapters
1.0 Introduction .................................................................................................................. 1-1
1.1 Project Background ................................................................................................... 1-1
1.2 Purpose of the EIR.................................................................................................... 1-1
1.3 Use of a Supplemental EIR ....................................................................................... 1-1
1.4 Scoping Process ....................................................................................................... 1-2
1.5 Draft Supplemental Environmental Impact Report..................................................... 1-2
1.5 EIR Contents ............................................................................................................ 1-2
1.6 Use of this Document ................................................................................................ 1-3
1.7 Project Sponsors and Contact Information ................................................................ 1-3
1.8 Relationship to Other Documents ............................................................................. 1-3
2.0 Project Description ....................................................................................................... 2-1
2.1 Project Summary ...................................................................................................... 2-1
2.2 Project Location ........................................................................................................ 2-1
2.3 Project Background ................................................................................................... 2-1
2.4 Project Objectives ..................................................................................................... 2-4
2.5 Project Components ................................................................................................. 2-4
2.6 Areas of Disturbance ................................................................................................ 2-6
2.7 Construction Techniques .......................................................................................... 2-6
2.8 Project Schedule ....................................................................................................... 2-7
2.9 Plans to Be Prepared ................................................................................................ 2-7
2.10 Permits and Authorizations .................................................................................... 2-8
3.0 Environmental Setting .................................................................................................. 3-1
3.1 CEQA Requirement .................................................................................................. 3-1
3.2 Plans and Policies..................................................................................................... 3-1
3.3 Cumulative Development Scenario ........................................................................... 3-3
4.0 Impact Assessment ...................................................................................................... 4-1
4.1 Aesthetic Resources ................................................................................................. 4-1
4.2 Air Quality/Greenhouse Gases................................................................................ 4-11
4.3 Biological Resources .............................................................................................. 4-21
4.4 Cultural Resources ................................................................................................. 4-43
4.5 Hazards and Hazardous Materials .......................................................................... 4-50
4.6 Hydrology / Water Quality ....................................................................................... 4-57
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Mid-Higuera Bypass Project FSEIR
4.7 Noise ...................................................................................................................... 4-64
5.0 Other CEQA-mandated Sections .................................................................................. 5-1
5.1 Section 15126 Topics ............................................................................................... 5-1
5.2 Appendix F: Energy Conservation ............................................................................. 5-2
6.0 Alternatives Analysis .................................................................................................... 6-1
6.1 Introduction ............................................................................................................... 6-1
6.2 Alternative Evaluation ............................................................................................... 6-1
6.3 Land Purchase/Business Relocation ......................................................................... 6-2
6.4 Marsh Street Bridge Replacement ............................................................................ 6-2
6.5 No Project Alternative ............................................................................................... 6-2
6.6 Environmentally Superior Alternative ........................................................................ 6-3
7.0 References and Preparers ........................................................................................... 7-1
Figures
2-1 Vicinity Map ....................................................................................................................2-2
2-2 Location Map ..................................................................................................................2-3
AR-1 Location and direction of Key Viewing Areas ...............................................................4-6
AR-2 KVA 1 - Existing view ..................................................................................................4-7
AR-3 KVA 1 – Photo-Simulation ...........................................................................................4-7
AR-4 KVA-2 - Existing view ..................................................................................................4-9
AR-5 KVA-2 - Photo-Simulation ............................................................................................4-9
Jurisdictional Areas Map – North ........................................................................................ 4-31
Jurisdictional Areas Map – South ....................................................................................... 4-32
CR-1 – Birds Eye View of San Luis Obispo ........................................................................ 4-44
HWQ-1 Floodplain Map ...................................................................................................... 4-59
NS-1 Sensitive Receptors Map ........................................................................................... 4-65
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Table of Contents
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Mid-Higuera Bypass Project FSEIR
Tables
2.1 Approximate Areas of Disturbance .................................................................................2-6
2.2 Anticipated Permits and Authorizations ...........................................................................2-8
AQ-1 Summary of Ambient Air Quality Standards & Attainment Designations .................... 4-12
AQ-2 Construction Emissions ............................................................................................. 4-16
AQ-3 Construction GHG Emissions .................................................................................... 4-20
BR-1 Impacts to Vegetation Communities .......................................................................... 4-29
BR-2 Tree Removal ............................................................................................................ 4-29
BR-3 Impacts to Jurisdictional Features (acres) ................................................................. 4-30
HWQ-1 San Luis Obispo Creek Peak Flows ....................................................................... 4-58
NS-1 Typical Construction Equipment Noise Levels ........................................................... 4-68
6.1 Alternatives Analysis .......................................................................................................6-4
Appendices
A. Notice of Preparation and Responses
B. Project Plans
C. Air Quality Background Information
D. Biological Resources Background Information
E. Response to Comments on the Draft Supplemental Impact Report
F. Mitigation Monitoring and Reporting Plan
Page 33 of 126
1.0 Introduction
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Mid-Higuera Bypass Project FSEIR
1.0 Introduction
1.1 Project Background
This Final Supplemental Environmental Impact Report (FSEIR) addresses the environmental
effects of the construction and operation of the Mid-Higuera Bypass Project (project). The
information presented here supplements the October 2003 San Luis Obispo Creek Watershed
Waterway Management Plan Final Programmatic Environmental Impact Report/Environmental
Impact Statement (EIR/EIS). The EIR/EIS is available for review at the County Public Works
Department. As described in the EIR/EIS:
“This Program level EIS/R addresses the potential environmental impacts of the proposed SLO
Creek Waterway Management Program that includes the Waterway Management Plan, the
Stream Maintenance and Management Plan and the Drainage Design Manual. The Program is
a combination of policies, programs and plans to address, in a regional or watershed-wide
manner, flooding and flood control along San Luis Obispo Creek and its tributaries.”
The project was specifically discussed in the EIR/EIS as one of five Capital Improvement
Projects; however, it was determined that subsequent environmental review would be required
at such time as project-specific data was available for review.
1.2 Purpose of the EIR
The goal of the California Environmental Quality Act (CEQA) is to:
1. Inform government decision makers and the public about the potential significant
environmental impacts of proposed activities; and
2. Identify ways that environmental impact(s) can be avoided or significantly reduced.
The purpose of an EIR is to provide State and local agencies and the general public with
detailed information on the potentially significant environmental effects which a proposed project
is likely to have, to list ways which the significant environmental effects may be minimized, and
indicate alternatives to the project.
This SEIR has been prepared in accordance with CEQA as amended, and the latest State
Guidelines for the Implementation of CEQA. The need for a SEIR is justified based upon the
review of project-specific design, the completion of project-specific technical reports, and the
completion of an Initial Study for the project (Refer to Appendix A).
1.3 Use of a Supplemental EIR
Once an EIR has been prepared for a project, a Lead Agency can generally rely on that EIR as
the CEQA “clearance” for that project. However, in some cases projects, or the circumstances
under which they occur, may change after the EIR is completed. More commonly, a period of
time passes between completion of the EIR and the implementation of the project. At this point,
a Lead Agency must determine whether the original EIR is still adequate for the project or
whether additional environmental review is required. The additional environmental review could
include an addendum or subsequent EIR.
The key findings for preparation of this SEIR are in section 15162(2) of the CEQA Guidelines in
that the level of detail now available in regards to the project description and the severity of
potential impacts constitutes a “substantial change” that requires revisions of the previous
EIR/EIS.
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1.0 Introduction
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Mid-Higuera Bypass Project FSEIR
1.4 Scoping Process
In accordance with the provisions of the State CEQA Guidelines, a Notice of Preparation (NOP)
for the project was distributed on February 19, 2016. The advertised comment period ended on
March 21, 2016. A total of 5 responses were received. These are included in Appendix A.
1.5 Draft Supplemental Environmental Impact Report
The Draft Environmental Impact Report (DSEIR) was released for public comment on
September 23, 2016 for a 45-day public review period. The review period closed on November
7, 2016. The District received four comment letters, three from public agencies, and one from a
member of the public. Appendix E of the Final EIR describes persons, organizations, and public
agencies commenting on the DSEIR; verbatim comments received through the EIR process;
and responses by the lead agency to comments received. The comments did not result in any
significant new information or substantial revisions to the DSEIR.
1.5 EIR Contents
The EIR is divided into the following major sections:
Executive Summary. Provides a brief summary of the project background, description, impacts
and mitigation measures, and alternatives.
Introduction. Provides the purpose of an EIR, as well as scope, content, and the use of the
document.
Project Description. Provides the general background of the project, objectives, a detailed
description of the project characteristics, and a listing of necessary permits and government
approvals.
Environmental Setting. Describes the surrounding land uses as well as plans and polices that
are relevant to the project. The section also includes a discussion of the projects consistency
with those plans and policies.
Environmental Impacts and Mitigation Measures. Discusses the environmental setting as it
relates to the various issue areas, regulatory settings, thresholds of significance, impact
assessment, project-specific impacts and mitigation measures, cumulative impacts, and
secondary impacts. Based on review of the EIR/EIS, the current project description, technical
reports, preparation of an Initial Study, and comments received on the NOP, the following
issues are covered in detail within the SEIR:
x Aesthetic Resources
x Air Quality / Greenhouse Gases
x Biological Resources
x Cultural Resources
x Hazards and Hazardous Materials
x Hydrology / Water Quality
x Noise
Other study areas typically fully analyzed in a EIR were not identified as having the likelihood of
significant effects, or are already addressed in the EIR/EIS. The reader should refer to the Initial
Study in Appendix A for additional information on that determination.
Other CEQA Mandated Topics. Identifies potential growth inducing impacts, irreversible
environmental changes and energy conservation.
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1.0 Introduction
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Mid-Higuera Bypass Project FSEIR
Alternatives. Summarizes the environmental advantages and disadvantages associated with the
project and alternatives. As required, the “No Project” alternative is included among the
alternatives considered. An “Environmentally Superior Alternative,” is identified.
1.6 Use of this Document
The following agencies may use this FSEIR in reviewing and issuing their respective permits
and authorizations (as applicable):
x United States Army Corps of Engineers (USACE)
x California Department of Fish and Wildlife (CDFW)
x Regional Water Quality Control Board (RWQCB)
x California Department of Transportation (Caltrans)
x San Luis Obispo County Air Pollution Control District (SLOAPCD)
x United States Fish and Wildlife Service (USFWS)
x National marine Fisheries Service (NMFS)
x City of San Luis Obispo
1.7 Project Sponsors and Contact Information
Key contact persons are as follows:
Lead Agency
San Luis Obispo County Flood Control and Water Conservation District
County Government Center, Room 200
San Luis Obispo, CA 93408
Mr. Keith Miller, Environmental Resource Specialist
Project Proponent
San Luis Obispo County Flood Control and Water Conservation District
County Government Center Room 200
San Luis Obispo, CA 93408
Ms. Jill Ogren, Project Manager
1.8 Relationship to Other Documents
This FSEIR supplements the 2003 EIR/EIS. The analysis contained here is intended to make
the changes and additions necessary to make the EIR/EIS adequate for the evaluation of the
currently proposed project. The EIR/EIS addressed a wide range of impacts to resources
throughout the San Luis Obispo Creek Watershed. The EIR/EIS was prepared to satisfy
National Environmental Policy Act (NEPA) requirements as well. This FSEIR focuses only on
those effects not considered in the EIR/EIS that would occur as a result of the specific project.
Further it does not include issues that were covered in the EIR/EIS that are primarily required by
NEPA – socioeconomics, for example. Copies of the EIR/EIS are available for review from the
San Luis Obispo County Department of Public Works.
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2.1 Project Summary
The Mid-Higuera Bypass Project (project) is proposed to increase the flood control capacity of
San Luis Obispo Creek (creek) between Marsh Street and Madonna Road due to the following
concerns:
x there is currently less than 25-year storm capacity in this stretch of the creek;
x significant bank erosion exists in some locations;
x there is localized sediment accumulation, particularly at the Marsh Street Bridge;
x a poor pool-to-riffle ratio exists;
x substantial invasive species and exotic plants are present; and
x there is a lack of continuity and/or diversity in native riparian vegetation
The proposed project includes five components developed to directly address these issues,
including:
1. excavation of two new channels (South Street Bypass and the Bianchi Bypass) that
bypass the existing creek channel and be active during large storm events;
2. construction of channel terraces/benches and a flow return located adjacent to but
above the OHWM to increase capacity;
3. sediment removal at the Marsh Street Bridge;
4. replacement of the Bianchi Lane Bridge with a taller, wider bridge; and
5. riparian habitat enhancement, including the removal of invasive species, promotion of a
canopy of native species and willows overhanging pools, as well as the installation of
strategically located habitat features such as pool forming root wads, rock deflectors,
and vegetated rock slope protection.
The project was identified in both the City of San Luis Obispo’s (City) Waterway Management
Plan (WMP) and the associated EIR/EIS; however, in 2003 when the EIR/EIS was prepared the
project had only been developed to a conceptual level and could not be evaluated in the detail
required to satisfy CEQA requirements.
2.2 Project Location
The project is located within and adjacent to the creek between the Marsh Street Bridge
(upstream) and Madonna Road Bridge (downstream). It is bordered on the west by Highway
101 and on the east by Higuera Street. It is located completely within the City of San Luis
Obispo (refer to Figures 2-1 and 2-2).
2.3 Project Background
The creek has flooded on multiple occasions in the last 40 years between Marsh Street and
Madonna Road. The water level in the creek, immediately north of the Marsh Street Bridge,
rises above the top of the creek bank during periods of heavy rain. The creek water
subsequently flows into the adjacent City Streets, damaging public and private property.
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Project area
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The City, in conjunction with the County of San Luis Obispo Flood Control and Water
Conservation District Zone 9 (Zone 9), undertook and adopted the WMP after the 1995 flooding
of Higuera and surrounding streets. Several flood control projects were incorporated in the
WMP, including the original Mid-Higuera Bypass project.
In 2008, the Zone 9 Advisory Committee reduced the original project scope to include work that
would only occur on City of San Luis Obispo property because of significant property acquisition
costs. Subsequent engineering assessments confirmed that the reduced scope would still
reduce local flooding. Following the release of the study results, additional funding for
preliminary environmental studies was approved by the San Luis Obispo County Board of
Supervisors. The preliminary environmental studies showed no unusual site conditions that
would be a barrier to project completion.
At the same time Zone 9 began pursuing a small property swap with a property owner adjacent
to the City’s property near the Bianchi Lane Bridge. The property swap is required in order to
provide additional approach space for the project’s first bypass element to be constructed. This
element consists of the removal and replacement of the Bianchi Lane Bridge. Additional studies
were conducted between 2011 and 2015 including preliminary design and an alternatives
analysis. Following completion of the alternatives analysis, the Zone 9 Advisory Committee
selected and identified the preferred project.
2.4 Project Objectives
The primary objective of the project is to increase the flood-carrying capacity (up to a 25-year
storm in some locations) of San Luis Obispo Creek from Marsh Street to Madonna Road, while
enhancing and protecting water quality as well as special-status species habitat within the
project area. Secondarily, the project will provide preliminary grading for a conceptual bike path
alignment which could be constructed in the future along a portion of the project area.
2.5 Project Components
Each of the five project components are described in more detail below. Site plans are included
in Attachment B.
2.5.1 Bypass Channels
The project would include the construction of two bypass channels, the Bianchi Bypass and the
South Street Bypass. The bypass channels are proposed between the creek and Highway 101.
They have been designed to be active during larger storm events (i.e. they are designed to be
“above” the Ordinary High Water Mark [OHWM] of the creek), and to flow full during 25-year
storm events. Vegetated rock slope protection as well as root wads/flow deflectors would be
installed at both the upstream and downstream transition areas between the bypass channels
and the creek.
The South Street Bypass would be approximately 600 feet long, and 10 to 12 feet deep. The
channel bottom would be approximately 20 feet wide and the maximum channel slopes would
be 2.5 horizontal to 1 vertical (2.5:1). The Bianchi Bypass is approximately 800 feet long and 6
to 8 feet deep. The channel bottom would be approximately 20 feet wide and the maximum
channel slopes would be 2:1. In addition, an approximately 14-foot-wide bench would be
constructed at the western edge of the Bianchi Bypass to accommodate a future bike route. No
other bicycle related improvements are proposed.
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2.5.2 Benches and Related Grading
In addition to the bypass channels, the capacity and functionality of the creek channel would be
expanded through the construction of four benches, by laying back slopes at a “pinch point”,
and through construction of a “flow return”. Similar to the bypass channels, the four benches
proposed would be excavated above the creek OHWM and would reach approximately 20-30
feet wide. The maximum slopes above the benches would be excavated no steeper than 2.5:1.
Pinch Point
The pinch point is a narrow approximately 120-foot-long section of the channel at approximately
306 South Higuera Street, where the banks are nearly vertical and bordered on both sides by
structures. The channel would be graded in this area so that the slopes were no steeper than
2.5:1 and then stabilized with willow cuttings, or potentially a structural retaining wall. Grading
may require removal or modification of one or both structures at this location. Final design of
this component is still under development and subject to the approval of the private landowners.
Flow Return
Historically, the creek has backed up on the upstream side of the Marsh Street Bridge causing
flow to spill out of the creek and down Higuera Street. Grading of a flow return at the Mathews
Open Space parcel just downstream of the Marsh Street Bridge at 320 Higuera Street, is
proposed to allow escaped creek flows to be redirected from Higuera Street back to the creek
channel. The proposed grading will create two broad swales designed to convey flood flow
across the property to the creek. The final design is recommended to include a sidewalk
underdrain, shorter curb height, or a modified driveway design to capture flow from the gutter in
Higuera Street.
2.5.3 Marsh Street Sediment Removal
Significant sediment has accumulated on the upstream side of the Marsh Street Bridge and
within the three bridge barrels. Further, the upstream sediment has formed an island that is
blocking the largest center barrel. To address this issue, sediment will be removed upstream of
the bridge, within the bridge barrels, and downstream of the bridge. The sediment would be
removed to 1-foot above the creek water surface elevation at time of construction. This strategy
will preserve the existing low flow channel through the bridge. In addition, the western bank will
be sloped back to a 2.5:1 slope.
2.5.4 Bianchi Lane Bridge Replacement
The existing Bianchi Lane Bridge is an old bridge that was relocated to its current position many
years ago. It is relatively low and narrow, and as a result can only accommodate flows from a 6-
year storm event. The proposed new bridge will be a two-span bridge with a higher deck
elevation and will incorporate the start of the first bypass channel. The new bridge will provide
capacity for an approximately 23-year storm event. The new bridge installation will include
grading to accommodate the new road approaches on either side.
2.5.5 Riparian Enhancement
Riparian enhancements have been incorporated for each of the components described above.
Vegetated rock slope protection would be installed at the confluence of the creek channel and
the bypass channels. At these locations, root wads would also be installed to provide pools and
habitat complexity to the creek. At the Bianchi Bypass downstream transition area, rock flow
deflectors will be installed to create pools and hydrologic complexity.
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The project components have been designed to avoid and/or minimize impacts to the existing
creek channel to the extent feasible. Nevertheless, the project does include substantial grading
and tree removal. It is estimated that approximately 150 trees will be removed during
construction. These include native and nonnative species. Native trees removed will be
replaced with native species and planted in accordance with the City’s Drainage Design Manual,
which includes planting smaller crown trees (i.e. willow, buckeye, elderberry) closer to the
channel and large crown trees (oak, cottonwood, bay) on the upper banks, which will provide a
shaded, open channel while allowing for storm water capacity in the channel over the long-term.
In addition, invasive species encountered during construction will be removed. These species
include castor bean, cape ivy, giant reed (arundo), and Himalayan blackberry, for example. A
Habitat Mitigation and Monitoring Plan (HMMP) will be prepared as part of the subsequent
permitting process. The HMMP will include specific performance criteria and guide
implementation of mitigation during and after project construction.
2.6 Areas of Disturbance
Preliminary estimates of the areas of disturbance associated with each project component are
included in Table 2.1.
Table 2.1. Approximate Areas of Disturbance
Component Disturbance (acres) Cut/Fill (yds3)
Bypass Channels
South Bypass 2.20 11,500 / 500
Bianchi Bypass 2.67 17,000 / 500
Benches/Grading
4 Benches 1.74 3,900 / 150
Pinch Point 0.44 2,300 / 1,200
Flow Return 0.50 940 / 50
Marsh Street Sediment Removal 0.45 2,100 / 0
Bianchi Lane Bridge 0.37 3,700 / 0
Total 8.37 43,840
2.7 Construction Techniques
Access - Construction access will be from Bianchi Lane, 306 and 320 Higuera Street, and South
Street. In order to move equipment to the west side of the creek it may be necessary to
construct one or more temporary crossings within the dewatered channel. Temporary crossings
are anticipated to be at grade across the creek, with a gravel driving surface. A construction
staging area would be located on the western side of the Bianchi Lane Bridge adjacent to the
Madonna Construction site in a paved area. Construction haul routes would include Higuera
Street, with trucks using either the Marsh Street or Madonna Road Highway 101 ramps.
Construction traffic would temporarily use Higuera Street, Marsh Street, Bianchi Lane, South
Street, and Brook Street during the busiest construction periods.
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Equipment - Heavy equipment including excavators, dozers, backhoes, dump trucks, and
cranes would be required to construct the project. In addition, various flatbed trucks, pick-up
trucks, generators, pumps, and smaller scale equipment would be used during construction.
Soil Export - Approximately 41,500 cubic yards of material may need to be exported. It may be
possible to re-use a portion of that material onsite to provide a vegetated or earthen screen
between Highway 101 and development along Higuera Street. Any exported soil will be hauled
to a location that can legally accept the material.
Dewatering - San Luis Obispo Creek is a perennial creek and therefore it is anticipated that
substantial dewatering will be necessary to construct each component. A preliminary dewatering
plan is included in Appendix B. As shown in the plans, dewatering would be conducted in three
areas. The final dewatering plan will be prepared subsequently during the permitting process.
2.8 Project Schedule
As currently proposed, all components will be constructed as a single project in an
approximately 12-month period (grading and major construction activities would be completed in
6 months). Standard resource agency permit requirements will restrict work during the rainy
season, and therefore construction will generally occur between June 1 and October 15 within
the creek banks. Work outside the permit areas (outside the creek banks) may start earlier, or
finish later than the permit restricted periods. Restoration monitoring would continue for
approximately 3-5 years after construction, depending upon revegetation success and permit
requirements.
2.9 Plans to Be Prepared
Prior to the issuance of the permits, the regulatory agencies will require a number of project-
specific plans to address potential biological resources impacts and water quality/hydrology
impacts. This EIR assumes all of these plans, or their equivalents, will be required and are
therefore considered part of the project description rather than mitigation. These plans include,
for example:
Diversion and Dewatering Plan –This plan would describe the various structures and measures
that intercept the creek flows upstream of the project site, tr ansport it around or through the
work area, and discharge it downstream, while avoiding water quality and special-status species
impacts. These plans are prepared by engineers in consultation with biologists. These plans
include such components as predicted diversion flow rates, pump capacities, material to be
used, appropriate permits and approvals, contingency plans, removal and restoration plan, as
well as design accommodations for special-status species.
Stormwater Pollution Prevention Plan (SWPPP)/Sedimentation and Erosion Control Plan
(SECP) – A SWPPP, which is also called an “erosion, sedimentation, and pollution prevention
plan,” or similar is generally required to comply with EPA's or the State's storm water
construction general permit. SWPPPs include pollution, prevention team; site description;
summary of potential pollutant sources; description of control measures; schedules and
procedures.
Spill Prevention Control and Contingency Plan (SPCC) – This plan presents a coordinated and
integrated set of procedures, methods and equipment requirements to prevent oil and
hazardous substance discharges into or upon waters and environment of the State and United
States, and to contain such discharges if they should occur. It provides guidelines for
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responsible facility personnel for communication and required coordination with and notification
of the Federal, State and local response systems when a spill occurs.
Habitat Mitigation and Monitoring Plan (HMMP) – HMMPs are prepared for projects that require
habitat restoration to mitigate for impacts to biological resources and wetlands and are generally
prepared to comply with authorizations from the USACE, RWQCB, and the CDFW. The HMMP
will typically involve a detailed description of the environmental setting, the existing values of the
areas of disturbance, mitigation goals and strategies, an implementation plan, performance
criteria, maintenance and monitoring specifications and contingency plans. The HMMP also
describes site preparation activities, such as amending and redistributing topsoil, seeding and
planting, and provides recommendations for temporary irrigation systems and fencing, including
detailed construction drawings and specifications.
2.10 Permits and Authorizations
The project will require permits from, local, state and federal resource agencies. A list of permits
and/or authorizations that may be required is included in Table 2.2.
Table 2.2 Anticipated Permits and Authorizations
Agency Permit Required
City of San Luis Obispo Grading Permit
Central Coast Regional Water Quality
Control Board (RWQCB) Section 401 Water Quality Certification
California Department of Fish and Wildlife
(CDFW) Section 1602 Streambed Alteration Agreement
California Department of Transportation
(Caltrans) Encroachment Permit
Air Pollution Control District
Authority to Construct
NESHAP Permit
US Army Corps of Engineers (ACOE) Section 404 Clean Water Act Permit
National Marine Fisheries Service Biological Opinion
US Fish and Wildlife Service Biological Opinion
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3.0 Environmental Setting
The following section describes the plans and policies that are relevant to the proposed project
and evaluates qualitatively whether or not the project is consistent with those plans and policies.
In addition, this section describes the cumulative development scenario, which in turn provides
the basis for the cumulative impact discussions in Chapter 4.
3.1 CEQA Requirement
CEQA Guidelines section 15125 requires that an EIR discuss
“any inconsistencies between the proposed project and applicable general plans and regional
plans. Such regional plans include, but are not limited to, the applicable air quality attainment or
maintenance plan or State Implementation Plan, area-wide waste treatment and water quality
control plans, regional transportation plans, regional housing allocation plans, habitat
conservation plans, natural community conservation plans and regional land use plans…”
The following section describes the planning documents applicable to the project and describes
any potential inconsistencies, when applicable.
3.2 Plans and Policies
3.2.1 Waterway Management Program Documents
The Waterway Management Plan (WMP) program is a set of three documents, referred to as
Volumes I, II, and III. Volume I contains inventory information, a detailed hydrologic and
hydraulic analysis of the watershed and its main tributaries, as well as an identification of the
management problems and needs of the waterways. Alternatives for addressing flooding, bank
instability, and habitat protection and enhancement, are include and a preferred project is
presented. The Mid-Higuera Bypass project is specifically described as one component of the
“preferred project” in the WMP (project SLO I-3).
Volume II is referred to as the Stream Management and Maintenance Program (SMMP) for the
waterways of the San Luis Obispo Creek watershed. This document outlines the planning,
design, and permitting approach the City and County will utilize for routine stream maintenance,
such as vegetation management, bank repair, and sediment removal. Policies and Best
Management Practices for these activities are also described. Capital projects, such as the
proposed project are not discussed within Volume II, although the proposed maintenance
activities discussed in Volume II may be necessary within the project area over the long-term in
order to maintain both the flood capacity and environmental benefits of the project.
Volume III is a Drainage Design Manual (DDM), which contains revised policies for floodplain
and stream corridor management and provides new design flows for stream channels within the
City of San Luis Obispo. The DDM presents procedures for hydrologic and hydraulic analysis,
and guidelines and design criteria for the design of channel, storm drain systems, stormwater
detention facilities, bank repair and stream restoration, and erosion control. Important policy
revisions of the DDM are also summarized in this Volume (Waterway Management Plan). The
DDM objectives include:
1. Ensure that stormwater runoff in the San Luis Obispo (SLO) Creek watershed is
adequately controlled to reduce flood and environmental damage from new development
and redevelopment projects.
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2. Ensure that stormwater is carried through a system of waterways and conduits in such a
way that flood water surface elevations and corresponding flood damage does not
increase, damage is minimized at existing and future building sites, and existing flood
water surface elevations are reduced wherever feasible;
3. Ensure that the creeks, channels, and waterways remain relatively stable, or are
stabilized following development or redevelopment projects, and other projects such as
bank repair and hydraulic structures constructed near or along the waterways;
4. Preserve and protect natural biological resources along creeks and waterways, including
their functions and values, and ensure that they are restored and enhanced wherever
possible, and;
5. Protect and improve water quality.
The DDM was used by the project engineers to design the project. Proposed drainage and
stormwater control structures, habitat improvements, and revegetation strategies proposed are
taken directly from the DDM.
3.2.2 City of San Luis Obispo General Plan Land Use Element (LUE)
The primary zoning designations within the project area are Open Space, and General Retail,
although Services and Manufacturing (Madonna Construction parcel), and Park (Caltrans
facility) also exist. Much of the disturbance and construction activities would occur within the
City-owned parcels, which are zoned Open Space. The Land Use Elements “Creeks Wetlands,
and Flooding Policies” are described as follows in the LUE.
“San Luis Obispo's aquatic ecosystems consist of creeks, Laguna Lake, floodplains, marshes,
wetlands, serpentine seeps, and springs. These aquatic ecosystems provide habitat, recreation,
water purification, groundwater recharge, and soil production as well as natural flood protection
by reducing the force of floodwaters as they spread and decelerate over floodplains. Creeks,
which are the most obvious of these systems because they flow under and through the City,
provide wildlife habitat, backyard retreats, and viewing and hiking pleasures, in addition to
carrying storm water runoff. When some creeks overflow during major storms, they flood wide
areas beyond their channels. San Luis Obispo wants to avoid injury or substantial property
losses from flooding, while keeping or improving the creeks' natural character, scenic
appearance, recreational value, and fish and wildlife habitat.”
The proposed project is consistent with these general objectives as it is intended to reduce the
potential for flooding while improving fish and wildlife habitat. In addition, the project is cognizant
of the potential for a future bike trail in the area and has incorporated a potential future bike lane
into the grading design.
3.2.3 City of San Luis Obispo General Plan Conservation and Open Space Element
The goal of the Conservation and Open Space Element of the General Plan is to protect
resources such as air and water, wildlife habitat, scenic and agricultural lands, watershed and
historic features. A secondary goal is to accommodate passive recreation if it will “…not harm
the environment or interfere with agricultural operations.” Section 7 of the Conservation Element
discusses “Natural Communities” within the City limits. Policies in the element relevant to the
proposed project include:
7.3.1(A) Protect listed species. The City will identify the location, habitat and buffer needs of
species listed for protection. This information will be developed by qualified people early in the
planning and development review process.
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7.5.1 Protection of significant trees. Significant trees, as determined by the City Council upon
the recommendation of the Tree Committee, Planning or Architectural Review Committee, are
those making substantial contributions to natural habitat or to the urban landscape due to their
species, size, or rarity. Significant trees, particularly native species, shall be protected. Removal
of significant trees shall be subject to the criteria and mitigation requirements in Chapter 8.6.3.
Oak Woodland communities in the Greenbelt and in open space areas shall be protected.
7.5.5. Soil conservation and landform modification. Public and private development projects
shall be designed to prevent soil erosion, minimize landform modifications to avoid habitat
disturbance and conserve and reuse on-site soils.
7.7.6. Replace invasive, non-native vegetation with native vegetation. The City and private
development will protect and enhance habitat by removing invasive, non-native vegetation that
detracts from habitat values and by replanting it with native California plant species. The Natural
Resources Manger will prioritize projects and enlist the help of properly trained volunteers to
assist in non-native vegetation removal and replanting when appropriate.
The proposed project is generally consistent with these policies. The project does include
substantial landform modification, but this is proposed in part as a way to avoid directly
disturbing large portions of the creek channel.
3.2.4 City of San Luis Obispo Mid-Higuera Enhancement Plan
The Mid-Higuera Enhancement Plan (Plan) was prepared in 2001 and includes policies and
public investment strategies with a goal of making the Mid-Higuera area more attractive and
functional. The Plan boundaries extend from the corner of Marsh and Higuera Street south to
approximately the cemetery area near the intersection of Elks Lane and Higuera Street. The
plan area extends from Highway 101 on the west to approximately Walker and Beebee Street.
The Plan describes the existing flooding problems in the area and specifically describes the
possible causes. The flooding potential was noted as a significant constraint to future
enhancement/redevelopment in the area. The plan describes several mitigation strategies for
addressing the flooding potential, including the construction of terraces, bypass channels, and
replacement of the Marsh Street Bridge. The plan also recommends making better use of the
City-owned open spaces in the area, by constructing a bike trail, for example. No
inconsistencies between the Plan and the proposed project were identified.
3.3 Cumulative Development Scenario
CEQA Guidelines Section 15355 states that a cumulative impact:
“refers to two or more individual effects which, when considered together, are considerable or
which compound or increase other environmental impacts.”
An analysis of potential cumulative effects requires developing a list of probable future projects
that with impacts relevant to the proposed project, known as the “cumulative development
scenario.” A review of probable future projects in the region surrounding the Creek have been
identified below. They are either in proximity to the proposed project, and/or have similar
characteristics, and are therefore likely to contribute cumulatively to environmental impacts.
However, each environmental issue will evaluate potentially cumulative considerable impacts
based on scenarios appropriate for the section. For example, cumulative air quality effects may
be considered as they impact the entire air basin, while it is more appropriate to identify
cumulative noise impacts as they relate to sensitive receptors in the vicinity of the project
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corridor. Cumulative effects have been included within each resource issue area discussed in
this EIR (refer to Chapter 4). The proposed project extends through a relatively rural area.
SLO Creek Sediment Management Projects
The City routinely removes sediment that has accumulated in 5 to 10 different areas of SLO
Creek and its tributaries. Work is conducted in the dry season in areas with no standing or
flowing water at different locations every 1-5 years. Timing is dependent on funding, deposition
rates, and permitting timeframes. Work is conducted under the City’s Programmatic Streambed
Alteration Agreement and also requires permits from the Regional Water Quality Control Board
and the US Army Corps of Engineers. One of these projects is located just above the Marsh
Street Bridge, where grading as part of the proposed project is located. Work is conducted
consistent with the Waterway Management Plan.
Bob Jones Bike Path - Octagon Barn to the Ontario Road Staging Area
This project is an approximately 4.4-mile-long section of this Class I (separated from traffic)
bikeway roughly paralleling the San Luis Obispo Creek corridor between San Luis Obispo and
Avila Beach. An EIR for the project was certified in February 2015 (SCH#2010031121). Impacts
identified in that document included temporary and permanent impacts to biological resources,
including species and vegetation communities similar to those which would be impacted by the
proposed project, as well as impacts to visual resources; however, all impacts are considered
less-than-significant with mitigation.
Mid-Higuera Area Redevelopment Projects
Based on information from the City of San Luis Obispo Community Development Department,
there are a number of projects that are planned, permitted, or for which applications have been
submitted to the City. The list includes such projects as:
x 205 Higuera Street – Discussions of conversion of commercial space into office space
x 245 Higuera Street – Adaptive re-use commercial building into mixed use with two new
residential units
x 283 Higuera Street – Reconstruction of “The Sub” (existing building burned down)
x 311 Higuera Street – Use permit approved for Bar/Tavern within existing building
footprint
These projects are relatively small, urban redevelopment projects located on the eastside of
Higuera Street; therefore, they would not contribute cumulatively to any impacts to the San Luis
Obispo Creek corridor.
Redevelopment of the Caltrans facilities on either side of Madonna Road near the intersection
of Higuera Street to create a convention center and parking area has been proposed in concept;
however, any project at the Caltrans site would need to conform to more recent creek setback
policy, and therefore may ultimately have a beneficial impact to creek resources. The project is
not expected to contribute cumulatively to impacts to the creek corridor.
SLO Creek Arundo Removal Projects
The San Luis Obispo Land Conservancy has actively monitored/managed more than 400
arundo populations since 2005. Work is ongoing annually. Populations are treated with
herbicide, and removed mechanically or by hand. This project would have beneficial impacts to
the watershed as arundo is highly invasive.
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4.1 Aesthetic Resources
This section describes the existing visual setting along the project corridor and describes the
potential changes to that setting that could result from the project – primarily the vegetation
removal, but also any changes in landform related to the proposed grading. A visual
assessment was prepared for the project (SWCA 2016). This section summarizes that
document and includes the photo-simulations prepared. The visual assessment is available for
review from the County Public Works Department.
4.1.1 Existing Conditions
Mature vegetation is the dominant visual characteristic along the project corridor. The
vegetation corridor is approximately 150 feet wide, with the larger trees in the corridor more than
100 feet tall. In addition to the taller trees, which include eucalyptus and walnut, for example,
numerous lower growing trees and shrubs exist throughout the corridor.
The creek channel is the dominant landform within the corridor. Where development has not
encroached on the creek, primarily on the western side, there is a relatively flat bench. Other
natural landforms include a small, approximately 20-foot-tall knoll west of the proposed Bianchi
Bypass.
The built environment within the project area include the three bridges – Marsh Street, Bianchi
Lane, and Madonna Road – culverts, chainlink fencing, a number of sacrete walls within the
channel, as well as the commercial and industrial developments along the Mid-Higuera corridor.
The visual setting varies considerably depending upon which side of the corridor the viewer is
on. The vegetation and landforms are generally visible from the west (i.e. Highway 101), while
the commercial and residential developments are generally only visible from public roads to the
east of the project site, such as South Higuera Street. The visual assessment prepared for the
project determined that:
“The existing visual quality of the project site and its surroundings is moderately high because of
the intrinsic value of the creek and its mature vegetation, the generally low-intensity of the
surrounding development, and the availability of views to the surrounding hillsides and
mountains.”
Figure 11 of the Scenic Roadways and Vistas Map of the City of San Luis Obispo General Plan
Conservation and Open Space Element describes the project frontage along Highway 101 in
the area of Bianchi Lane as providing “Moderate Scenic Value”.
4.1.2 Regulatory Setting
The City’s General Plan documents including the Circulation Element, Conservation and Open
Space Element, Parks and Recreation Element, and Land Use Element include multiple policies
and programs that address the scenic value of the City’s open spaces, including the creek. A
sample of the policies is included below. A complete list of relevant policies is included in the
visual assessment.
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Circulation Element
15.1.2 Development Along Scenic Routes. The City will preserve and improve views of
important scenic resources form streets and roads. Development along scenic roadways should
not block views or detract from the quality of views.
15.1.3. Public Equipment and Facilities. The City and other agencies should be encouraged to
avoid cluttering scenic roadways with utility and circulation-related equipment and facilities.
Conservation and Open Space Element
9.1.1. Preserve natural and agricultural landscapes. C. The City’s non-emergency repair,
maintenance, and small construction projects in highly visible locations, such as hillsides and
downtown creeks, where scenic resources could be affected, shall be subject to at least “minor
or incidental” architectural review.
9.2.1. Views to and from public places, including scenic roadways. The City will preserve and
improve views of important scenic resources from public places, and encourage other agencies
with jurisdiction to do so. Public places include parks, plazas, the grounds of civic buildings,
streets and roads, and publicly accessible open space. In particular, the route segments shown
in Figure 11 are designated as scenic roadways.
Land Use Element
6.3. Open Space Policies. The City shall require that buildings, lighting, paving, use of vehicles,
and alterations to the landforms and native or cultural landscapes on open space lands are
minimized, so rural character and resources are maintained.
4.1.3 Significance Criteria
The significance of potential aesthetic resources impacts is based on thresholds identified within
Appendix G of the CEQA Guidelines. Appendix G provides the following thresholds for
determining significance with respect to aesthetic resources. Aesthetic resources impacts would
be considered significant if the proposed project would:
1. Have a substantial adverse effect on a scenic vista;
2. Substantially damage scenic resources, including, but not limited to, trees, rock
outcroppings, and historic buildings within a state scenic highway;
3. Substantially degrade the existing visual character or quality of the site and its
surroundings; or
4. Create a new source of substantial light or glare which would adversely affect day or
nighttime views in the area?
Because the project is not visible from any scenic highways, that threshold is not applicable.
Further, no new source of lighting or glare is proposed and therefore that threshold is not
applicable.
4.1.4 Impacts and Mitigation Measures
This section describes potential impacts and is organized based on the significance criteria
outlined above.
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4.1.4.1 Have a substantial adverse effect on a scenic vista
Scenic vistas identified in the area include primarily Cerro San Luis, and secondarily the South
Street Hills, and the Cuesta Ridge, including their intermediate slopes that contain pastures,
vegetated drainage features, open space, and rocky buttes.
When viewed from the east, the vegetation in the project corridor provides some context for
views of Cerro San Luis; however, the vegetation also limits the views of Cerro San Luis in
some locations. For example, the mature vegetation generally blocks views of Cerro San Luis
for those travelling northbound on Higuera Street near the Flow Return/Mathews Open Space
area.
When viewed from the east (i.e. from Highway 101 and the Madonna Inn Bicycle Path), the
creek does provide a vegetated foreground for views of the South Street Hills as well as Cuesta
Ridge. These vistas, while not as scenic as views toward Cerro San Luis, do contribute to the
visual quality of the area. Areas of extensive vegetation removal and earthwork along the creek
that would open-up views to adjacent development would somewhat degrade the foreground
context of hillside vistas to the east. However, the project’s effect on views to Cerro San Luis to
the west, and the Cuesta Ridge and South Street Hills to the east would be minimal as seen
from surrounding public areas. Impacts to scenic vistas would be less than significant. No
mitigation is required.
4.1.4.2 Degrade the existing visual character or quality of the site and its surroundings
The visual assessment concludes that the creek corridor provides scenic quality on its own, but
also acts as a buffer between Highway 101 and the Mid-Higuera developments between Marsh
Street and Madonna Road. The substantial tree removal proposed for this area, which includes
approximately 150 mature trees, along with their associated understory would be noticeable to
motorists on Highway 101, those on the Madonna Inn Bicycle Trail, and at the Bianchi open
space area. In some areas the vegetation removal would have a limited effect, but in others
where it provides screening of the built environment, it would result in a noticeable change. This
is especially true in the areas near the South Street Bypass, where “new” views of the back of
the commercial uses along South Higuera would be more noticeable along an approximately
1,400-foot-long section of Highway 101. The bypass channels would generally be “below grade”
and not noticeable, although they would represent a new built environment element and could
be visible from the open space areas, including the future extension of the Bob Jones Trail.
The project proposes to revegetate disturbed areas with a mix of native species. Taller, single
trunk species such as cottonwood, bay laurel, and walnut would be planted in lieu of willows, to
allow for additional flood control capacity within the channel. Similarly, the density of the
revegetation will be limited to allow for flood capacity along the bypass channel and benches to
be excavated. This scenario is described in the Vegetation Enhancement Plan in Appendix B.
The visual assessment concludes that:
“Upon reaching maturity (approximately 15-20 years following initial planting), proposed
overstory and canopy tree species mentioned in the Vegetation Enhancement Plan would help
re-create much of the overall vegetated character of the site. Planting within the rock-slope
protection would eventually visually screen the engineered appearance of those features.”
The degradation of the visual character over the short and medium term is considered a
potentially significant impact.
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AR Impact 1 The project would cause a noticeable change to the visual environment of the
site and its surroundings due to a loss of vegetative character, visibility of engineered channels
and slope protection, and increased visibility to the development along Higuera Street, South
Street and the Caltrans building north of Madonna Road as seen from Highway 101.
AR-mm-1 Prior to initiation of the project, the District shall ensure that revised grading and
site plans shall show the following:
1. All channel benches and bypass channels shall employ contour grading
design and construction techniques to reduce their engineered appearance.
All grade breaks shall be rounded and avoid angular slope-interface.
2. All top-of-slope hinge-points shall employ slope-rounding where doing so
would not adversely affect existing vegetation.
AR-mm-2 Prior to initiation of the project, the District shall ensure preparation and
implementation of a planting plan, which shall supplement the Vegetation
Enhancement Plan, be developed and signed by a licensed landscape architect
or restoration specialist, and include the following:
1. Visual screen planting between the easternmost extent of channel and bench
grading and the adjacent parcels east of the project, between Stations 13+50
and 17+00, and between Stations 22+50 and 27+00.
2. Screen planting shall be a mix of evergreen trees and shrubs placed in
natural-looking patterns.
3. Trees planted for screening along the fence shall be planted from primarily
24-inch box containers. Shrubs shall be planted from minimum 5-gallon
containers.
4. Screen planting shall include the appropriate number and density of plants to
achieve a minimum of 90 percent visual screening of the adjacent
development as seen from Highway 101 within five years.
5. Additional planting between the bypass channels and the Highway 101 right-
of-way, to the maximum extent possible.
6. Planting along Highway 101 shall be a mix of evergreen trees and shrubs
placed in natural-looking patterns.
7. Trees planted along Highway 101 shall be planted from primarily 24-inch box
containers. Shrubs shall be planted from minimum 5-gallon containers.
Residual Impacts. For the first approximately five years after construction the project would
cause a noticeable change in the visual character of the project corridor. Over time, the planting
proposed, along with the measures described above, would re-establish the visual character
and screening. They would reduce the impacts to a less than significant level. No additional
measures are required.
4.1.4.3 Cumulative Impacts
The project area plays a role in the City’s overall aesthetic quality and character of the area. Any
changes to the character if combined with other changes along the Mid-Higuera corridor, for
example, could potentially contribute to an emerging perception that San Luis Obispo is
undergoing a visual change toward increasing development. However, none of the other
projects described in the cumulative development scenario propose tree removal along the
creek corridor. Because the project’s impacts are mitigated to a less than significant level, and
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no other projects currently propose substantial changes in the vegetation along the corridor,
potential cumulative impacts are less than significant. No additional mitigation is required.
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Figure AR-1. Location and direction of Key Viewing Areas (KVA) and orientation of view.
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4.2 Air Quality/Greenhouse Gases
This section describes the existing air quality setting in San Luis Obispo County and the
potential short-term and long-term air quality impacts associated with development of the
proposed project. Information in this section summarizes the report Air Quality and Greenhouse
Gas Impact Assessment for the Proposed Mid-Higuera Bypass Project (Ambient, 2016). This
section also includes a discussion of greenhouse gas (GHG) emissions associated with project
implementation. Emissions calculations summaries from the air quality modelling performed for
this project are included in Appendix C. The entire report is available for review from the County
FCWCD.
4.2.1 Existing Conditions
The proposed project is located in San Luis Obispo County, which is part of the South Central
Coast Air Basin (SCCAB) and within the jurisdiction of the SLOAPCD. Air quality in the SCCAB
is influenced by a variety of factors, including climate, topography, local and regional
meteorology. Regional meteorology is largely dominated by a persistent high pressure area
which commonly resides over the eastern Pacific Ocean. Seasonal variations in the strength
and position of this pressure cell cause seasonal changes in the weather patterns of the area.
The Pacific High remains generally fixed several hundred miles offshore from May through
September, enhancing onshore winds and opposing offshore winds. During spring and early
summer, as the onshore breezes pass over the cool water of the ocean, fog and low clouds
often form in the marine air layer along the coast. Surface heating in the interior valleys
dissipates the marine layer as it moves inland.
4.2.1.1 Criteria Air Pollutants
For the protection of public health and welfare, the Clean Air Act (CAA) required that the United
States Environmental Protection Agency (U.S. EPA) establish National Ambient Air Quality
Standards (NAAQS) for various pollutants. These pollutants are referred to as "criteria"
pollutants because the U.S. EPA publishes criteria documents to justify the choice of standards.
These standards define the maximum amount of an air pollutant that can be present in ambient
air without harm to the public’s health. An ambient air quality standard is generally specified as
a concentration averaged over a specific time period, such as one hour, eight hours, 24 hours,
or one year. The different averaging times and concentrations are meant to protect against
different exposure effects. The CAA allows states to adopt additional or more health-protective
standards. Standards and the County’s attainment designations are shown in Table AQ-1.
4.2.1.2 Toxic Air Contaminants
Toxic air contaminants (TACs) are air pollutants that may cause or contribute to an increase in
mortality or serious illness, or which may pose a hazard to human health. TACs are usually
present in minute quantities in the ambient air, but due to their high toxicity, they may pose a
threat to public health even at very low concentrations. Because there is no threshold level
below which adverse health impacts are not expected to occur, TACs differ from criteria
pollutants for which acceptable levels of exposure can be determined and for which state and
federal governments have set ambient air quality standards. TACs, therefore, are not
considered “criteria pollutants” under either the Federal Clean Air Act (FCAA) or the California
Clean Air Act (CCAA).
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Table AQ-1
Summary of Ambient Air Quality Standards & Attainment Designations
Source: Ambient 2016
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4.2.1.3 Asbestos
Asbestos is the common name for a group of naturally-occurring fibrous silicate minerals that
can separate into thin but strong and durable fibers. Naturally-occurring asbestos, which was
identified as a TAC in 1986 by the ARB, is located in many parts of California and is commonly
associated with ultramafic rock. The project site is located near areas that are likely to contain
ultramafic rock; however, geologic surveys in the project area have not identified any asbestos-
containing materials (Padre 2015).
4.2.1.4 Greenhouse Gases
Various gases in the earth’s atmosphere, classified as atmospheric GHGs, play a critical role in
determining the earth’s surface temperature. Solar radiation enters the earth’s atmosphere from
space and a portion of the radiation is absorbed by the earth’s surface. The earth emits this
radiation back toward space, but the properties of the radiation change from high-frequency
solar radiation to lower-frequency infrared radiation. GHGs, which are transparent to solar
radiation, are effective in absorbing infrared radiation. As a result, this radiation that otherwise
would have escaped back into space is now retained, resulting in a warming of the atmosphere.
This phenomenon is known as the greenhouse effect. Among the prominent GHGs contributing
to the greenhouse effect are carbon dioxide, methane, nitrous oxide, hydrofluorocarbons,
perfluorocarbons, and sulfur hexafluoride.
On a global scale, GHG emissions are predominantly associated with activities related to
energy production; changes in land use, such as deforestation and land clearing; industrial
sources; agricultural activities; transportation; waste and wastewater generation; and
commercial and residential land uses. World-wide, energy production including the burning of
coal, natural gas, and oil for electricity and heat is the largest single source of global GHG
emissions.
In 2013, GHG emissions within California totaled 459 million metric tons (MMT) of CO2e. Within
California, the transportation sector is the largest contributor, accounting for approximately 37
percent of the total statewide GHG emissions. Emissions associated with industrial uses are the
second largest contributor, totaling roughly 23 percent. Electricity generation totaled roughly 20
percent.
4.2.2 Methodology
Short-term construction emissions associated with the proposed project were calculated using
the CalEEMod, version 2013.2.2, computer program. Construction of the proposed
improvements would occur during the non-rainy season (April 15 through October 15).
Construction activities are anticipated to occur over a single six-month period, though it’s
possible that some activities may occur during the following year. However, to ensure a
conservative analysis, all activities were assumed to occur during the initial six-month period of
construction. Up to approximately 41,400 cy of material was assumed to be exported and
approximately 2,400 cy of material may need to be imported. Off-road equipment anticipated to
be required during construction was derived from similar projects and default assumptions
contained in CalEEMod. Actual equipment required may vary. Modeling assumptions and output
files are included in Appendix C.
4.2.3 Regulatory Setting
Air quality within the SCCAB is regulated by several jurisdictions including the U.S. EPA, Air
Resources Board (ARB), and the SLOAPCD. Each of these jurisdictions develops rules,
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regulations, and policies to attain the goals or directives imposed upon them through legislation.
Because the state and local regulations generally equal or exceed Federal regulations, they are
described in this section.
4.2.3.1 California Air Resources Board
The ARB is the agency responsible for coordination and oversight of state and local air pollution
control programs in California and for implementing the CCAA. Other ARB duties include
monitoring air quality (in conjunction with air monitoring networks maintained by air pollution
control districts and air quality management districts, establishing California Ambient Air Quality
Standards (CAAQS), which in many cases are more stringent than the NAAQS, and setting
emissions standards for new motor vehicles.
4.2.3.2 California Clean Air Act
The CCAA requires that all air districts in the state endeavor to achieve and maintain CAAQS
for Ozone, CO, SO2, and NO2 by the earliest practical date. The CCAA specifies that districts
focus particular attention on reducing the emissions from transportation and area-wide emission
sources, and the act provides districts with authority to regulate indirect sources. Each district
plan is required to either (1) achieve a five percent annual reduction, averaged over consecutive
3-year periods, in district-wide emissions of each non-attainment pollutant or its precursors, or
(2) to provide for implementation of all feasible measures to reduce emissions. Any planning
effort for air quality attainment would thus need to consider both state and federal planning
requirements.
4.2.3.3 Assembly Bill 32 - California Global Warming Solutions Act of 2006
“AB 32” requires that statewide GHG emissions be reduced to 1990 levels by the year 2020.
The gases that are regulated by AB 32 include carbon dioxide, methane, nitrous oxide,
hydrofluorocarbons, perfluorocarbons, nitrogen trifluoride, and sulfur hexafluoride. The reduction
to 1990 levels will be accomplished through an enforceable statewide cap on GHG emissions
that will be phased in starting in 2012. To effectively implement the cap, AB 32 directs ARB to
develop and implement regulations to reduce statewide GHG emissions from stationary
sources. AB 32 specifies that regulations adopted in response to AB 1493 should be used to
address GHG emissions from vehicles. However, AB 32 also includes language stating that if
the AB 1493 regulations cannot be implemented, then ARB should develop new regulations to
control vehicle GHG emissions under the authorization of AB 32.
AB 32 requires that ARB adopt a quantified cap on GHG emissions representing 1990
emissions levels and disclose how it arrives at the cap, institute a schedule to meet the
emissions cap, and develop tracking, reporting, and enforcement mechanisms to ensure that
the state achieves reductions in GHG emissions necessary to meet the cap. AB 32 also
includes guidance to institute emissions reductions in an economically efficient manner and
conditions to ensure that businesses and consumers are not unfairly affected by the reductions.
4.2.3.4 County of San Luis Obispo Air Pollution Control District
The SLOAPCD is the agency primarily responsible for ensuring that NAAQS and CAAQS are
not exceeded and that air quality conditions, including GHGs within the region are maintained.
Responsibilities of the SLOAPCD include, but are not limited to, preparing plans for the
attainment of ambient air quality standards, adopting and enforcing rules and regulations
concerning sources of air pollution, issuing permits for stationary sources of air pollution,
inspecting stationary sources of air pollution and responding to citizen complaints, monitoring
ambient air quality and meteorological conditions, and implementing programs and regulations
required by the FCAA and the CCAA.
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4.2.4 Significance Criteria
The significance of potential air quality impacts is based on thresholds identified within Appendix
G of the CEQA Guidelines and standards established within the SLOAPCD CEQA Air Quality
Handbook. Appendix G of the CEQA Guidelines provides the following thresholds for
determining significance with respect to air quality and GHGs. Air quality and GHG impacts
would be considered significant if the proposed project would:
1. Conflict with or obstruct implementation of the applicable clean air plan;
2. Violate any air quality standard or contribute substantially to an existing or projected air
quality violation;
3. Result in cumulatively considerable net increase of any criteria pollutant for which the
project region is non-attainment under an applicable federal or state ambient air quality
standard (including releasing emissions which exceed quantitative thresholds for ozone
precursors);
4. Expose sensitive receptors to substantial pollutant concentrations;
5. Create objectionable odors affecting a substantial number of people;
6. Generate greenhouse gas emissions, either directly or indirectly, that may have a
significant impact on the environment; or
7. The project conflict with an applicable plan, policy, or regulation adopted for the purpose
of reducing the emissions of greenhouse gases?
To assist in the evaluation of air quality impacts, the SLOAPCD has developed recommended
significance thresholds, which are contained in the SLOAPCD’s CEQA Air Quality Handbook
(2012). The threshold criteria established by the SLOAPCD to determine the significance and
appropriate mitigation level for a project’s short-term construction emissions are presented in
Table AQ-2.
4.2.5 Impacts and Mitigation Measures
This section describes impacts related to construction of the project and is organized based on
the significance criteria outlined above and the data provided in the tables below.
4.2.5.1 Conflict with or obstruct implementation of the applicable clean air plan
According to the SLOAPCD’s CEQA Air Quality Handbook (2012), a consistency analysis with
the Clean Air Plan is required for a program-level environmental review, and may be necessary
for a larger project-level environmental review, depending on the project being considered.
Project-level environmental reviews which may require consistency analysis with the Clean Air
Plan include: large residential developments and large commercial/industrial developments. For
such projects, evaluation of consistency is based on a comparison of the proposed project with
the land use and transportation control measures and strategies outlined in the Clean Air Plan.
If the project is consistent with these measures, the project is considered consistent with the
Clean Air Plan.
The proposed project is consistent with current zoning and would not result in increased
population or employment. In addition, the proposed project would not result in the installation of
any major stationary sources of emissions. For this reason, the proposed project would not
conflict with SLOAPCD’s Clean Air Plan. This impact is considered less than significant. No
mitigation is required.
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4.2.5.2 Violate any air quality standard or contribute substantially to an existing or
projected air quality violation
Estimated daily and quarterly emissions are summarized and compared to SLOAPCD’s
significance thresholds in Table AQ-2. Maximum daily construction-generated emissions of
ROG+NOX and exhaust PM10 could potentially exceed SLOAPCD significance thresholds.
Quarterly thresholds would not be exceeded. In addition, fugitive dust generated during
construction may result in localized pollutant concentrations that could result in increased
nuisance concerns to nearby residents.
Table AQ-2
Construction Emissions
Criteria Project
Emissions
Significance
Threshold
Threshold
Exceeded?
Daily Emissions (ROG+NOX) 220 lbs 137 lbs Yes
Daily Emissions (DPM) 10 lbs 7 lbs Yes
Quarterly Emissions (ROG+NOX) 1.9 tons 2.5 tons No
Quarterly Emissions (DPM) 0.09 tons 0.13 tons No
Quarterly Emissions (Fugitive PM) 0.3 tons 2.5 tons No
AQ Impact 1 Project construction activities would result in emissions levels that exceed
SLOAPCD thresholds.
AQ-mm 1 A Construction Activity Management Plan (CAMP) shall be prepared for the
proposed project. The CAMP shall be submitted to the SLOAPCD for review and approval prior
to the start of construction. The CAMP shall include, at a minimum, the following elements:
1. Identification of the project construction schedules. To the extent possible, construction
activities should be phased to minimize cumulative increases of daily emissions from
multiple activities.
2. Identification of schedules for truck hauling activities and associated haul routes. Haul
routes and schedules that would have the least impact to nearby sensitive receptors
shall be selected.
Construction activities and haul truck trips should be scheduled during non-peak hours
(as determined by the Public Works Director) to reduce peak hour emissions.
3. Identification of construction-equipment permitting requirements. Portable equipment, 50
horsepower (hp) or greater, used during construction activities may require California
statewide portable equipment registration (issued by the California Air Resources Board)
or a SLOAPCD permit. Examples of such equipment may include, but are not limited to,
standby generators, material processing equipment (e.g., crushers, conveyors, portable
batch plants, tub grinders, trammel screens).
4. Identification of a designated person or persons responsible for implementation of the
CAMP and emissions monitoring and compliance. The designated individual(s) shall be
responsible for monitoring of fugitive dust emissions and the
implementation/enhancement of measures, as necessary, to minimize dust complaints,
reduce visible emissions below the SLOAPCD’s limit of 20% opacity for greater than 3
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minutes in any 60-minute period. Their duties shall include holidays and weekend
periods when work may not be in progress. The name and telephone number of such
persons shall be provided to the SLOAPCD Compliance Division prior to the start of any
grading, earthwork or demolition.
5. Tabulation of on-road and off-road construction equipment. Emissions shall be quantified
in accordance with SLOAPCD-recommended methodologies based on project-specific
construction requirements (e.g., construction schedules, construction vehicle trips, and
off-road equipment fleet to be used during project construction.
6. Identification of fugitive dust and mobile-source emission control measures to be
implemented sufficient to demonstrate compliance with SLOAPCD’s CEQA thresholds of
significance and to minimize nuisance impacts at nearby sensitive receptors.
Residual Impact. This mitigation measure would reduce impacts to less than significant. No
additional mitigation is required.
4.2.5.3 Expose sensitive receptors to substantial pollutant concentrations
The project site is located within and adjacent to San Luis Obispo Creek between the Marsh
Street Bridge and Madonna Road Bridge. The proposed construction area is bordered on the
west by Highway 101 and on the east by Higuera Street and existing development. The
adjacent existing development consists largely of a mix of light industrial, commercial, and
residential land uses. The nearest residential dwellings are located adjacent to and east of San
Luis Obispo Creek along Brook Street, south of South Street. St. Luke Missionary Baptist
Church and Eto Park are also located along Brook Street, south of South Street. In addition,
Mathews Trailer Lodge is located adjacent to and east of San Luis Obispo Creek, south of
Bianchi Lane.
Demolition activities can have potential negative air quality impacts, including issues
surrounding proper handling, demolition, and disposal of asbestos containing material (ACM).
Asbestos containing materials could be encountered during demolition of existing structures,
particularly older structures constructed prior to 1970. Asbestos can also be found in various
building products, including (but not limited to) utility pipes/pipelines (transite pipes or insulation
on pipes). If a project will involve the disturbance or potential disturbance of ACM, various
regulatory requirements may apply, including the requirements stipulated in the National
Emission Standard for Hazardous Air Pollutants (40CFR61, Subpart M - Asbestos NESHAP).
The project site will require demolition of Bianchi Lane Bridge. As a result, demolition activities
have the potential to result in the disturbance of ACM.
Construction of the proposed project may result in the generation of fugitive dust. Fugitive dust
emissions would be primarily associated with earth-moving, material handling and demolition
activities, as well as vehicle travel on unpaved and paved surfaces. Onsite off-road equipment
and trucks would also result in short-term emissions of diesel-exhaust PM (DPM). Construction-
generated emissions of PM could result in localized concentrations of PM that could result in
increased nuisance impacts to nearby land uses and receptors.
Demolition of structures coated with lead based paint can have potential negative air quality
impacts and may adversely affect the health of nearby individuals. Improper demolition can
result in the release of lead containing particles from the site. Sandblasting or removal of paint
by heating with a heat gun can result in significant emissions of lead.
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AQ Impact 2 The project could expose sensitive receptors to pollutants such as lead and
fugitive dust.
AQ-mm 2 The following measures shall be implemented to reduce potential expose of
sensitive receptors to substantial pollutant concentrations. These measures shall also be
included in the CAMP to be prepared for this project
1. Demolition of onsite structures shall comply with the National Emission Standards for
Hazardous Air Emissions (NESHAP) requirements (NESHAP, 40 CFR, Part 61, Subpart
M) for the demolition of existing structures. The SLOAPCD is delegated authority by the
Environmental Protection Agency (EPA) to implement the Federal Asbestos NESHAP.
Prior to demolition of onsite structures, the SLOAPCD shall be notified, per NESHAP
requirements.
2. If during demolition of Bianchi Lane Bridge, paint is separated from the construction
materials (e.g. chemically or physically), the paint waste will be evaluated independently
from the building material by a qualified hazardous materials inspector to determine its
proper management. All hazardous materials shall be handled and disposed in
accordance with local, state and federal regulations.
3. According to the Department of Toxic Substances Control (DTSC), if paint is not
removed from the building material during demolition (and is not chipping or peeling), the
material can be disposed of as construction debris (a non-hazardous waste). The landfill
operator will be contacted prior to disposal of building material debris to determine any
specific requirements the landfill may have regarding the disposal of lead-based paint
materials. The disposal of demolition debris shall comply with any such requirements.
4. On-road diesel vehicles shall comply with Section 2485 of Title 13 of the California Code
of Regulations. In general, the regulation specifies that drivers of said vehicles:
x Shall not idle the vehicle’s primary diesel engine for greater than 5 minutes at
any location, except as noted in Subsection (d) of the regulation; and,
x Shall not operate a diesel-fueled auxiliary power system to power a heater, air
conditioner, or any ancillary equipment on that vehicle during sleeping or resting
in a sleeper berth for greater than 5.0 minutes at any location when within 1,000
feet of a restricted area, except as noted in Subsection (d) of the regulation.
x Off-road diesel equipment shall comply with the 5-minute idling restriction
identified in Section 2449(d)(2) of the California Air Resources Board’s In-Use
off-Road Diesel regulation.
x Signs must be posted in the designated queuing areas and job sites to remind
drivers and operators of the state’s 5-minute idling limit.
x Construction truck trips shall be scheduled, to the extent feasible, to occur during
non-peak hours.
x The burning of vegetative material shall be prohibited.
5. Should hydrocarbon contaminated soil be encountered during construction activities, the
SLOAPCD shall be notified as soon as possible and no later than 48 hours after affected
material is discovered to determine if a SLOAPCD Permit will be required. In addition,
the following measures shall be implemented immediately after contaminated soil is
discovered:
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x Covers on storage piles shall be maintained in place at all times in areas not
actively involved in soil addition or removal;
x Contaminated soil shall be covered with at least six inches of packed
uncontaminated soil or other TPH –non-permeable barrier such as plastic tarp.
No headspace shall be allowed where vapors could accumulate;
x Covered piles shall be designed in such a way to eliminate erosion due to wind
or water. No openings in the covers are permitted;
x The air quality impacts from the excavation and haul trips associated with
removing the contaminated soil must be evaluated and mitigated if total
emissions exceed the SLOAPCD’s construction phase thresholds;
x During soil excavation, odors shall not be evident to such a degree as to cause a
public nuisance; and,
x Clean soil must be segregated from contaminated soil.
Residual Impact. This measure, which address TACs and similar pollutants would reduce
impacts to a less than significant level. No additional mitigation is required.
4.2.5.4 Create objectionable odors affecting a substantial number of people
The proposed project would not result in the installation of any equipment or processes that
would result in odorous emissions. However, construction of the proposed project would involve
the use of a variety of gasoline or diesel-powered equipment that would emit exhaust fumes.
Exhaust fumes, particularly diesel exhaust, may be considered objectionable by some people.
In addition, pavement coatings and architectural coatings used during project construction
would also emit temporary odors. However, construction-generated emissions would occur
intermittently throughout the workday and would dissipate rapidly with increasing distance from
the source. As a result, short-term construction activities would not expose a substantial number
of people to frequent odorous emissions. For these reasons, potential exposure of sensitive
receptors to odorous emissions would be considered less than significant. No mitigation is
required.
4.2.5.5 Generate greenhouse gas emissions, either directly or indirectly, that may have a
significant impact on the environment
Estimated GHG emissions attributable to future development would be primarily associated with
increases of CO2 from mobile sources. To a lesser extent, other GHG pollutants, such as CH4
and N2O, would also be generated. Estimated increases in GHG emissions associated with
construction of the proposed project are summarized in Table AQ-2. Assuming that all
construction activities were to occur within a single year, annual emissions of GHGs would total
approximately 430.4 MTCO2e. There would also be a small amount of GHG emissions from
waste generated during construction; however, this amount is speculative. Short-term
construction-generated emissions would not exceed 1,150 MTCO2e/year. The proposed project
is consistent with current zoning and would not result in increased population or employment,
nor would the project result in the installation of any major stationary sources of emissions. As a
result, the proposed project is not anticipated to result in long-term increases of GHGs. Impacts
would be less than significant. No mitigation is required.
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Table AQ-3
Construction GHG Emissions
Construction Activity GHG Emissions
(MTCO2e/Year)
Bianchi Lane Bridge Demolition/Removal 27.3
Bianchi Lane Bridge Construction 18.5
Bianchi Lane Grading 4.6
Bianchi Lane Paving 3.0
Excavation of Two New By-Pass Channels 300.4
Construction of Terraces and Benches 63.4
Sediment Removal at Marsh Street Bridge 13.2
Construction Phase Total 430.4
SLOAPCD Significance Threshold 1,150
Exceeds Threshold? No
4.2.5.6 Would the project conflict with an applicable plan, policy, or regulation adopted
for the purpose of reducing the emissions of greenhouse gases?
The proposed project is consistent with current zoning and would not result in increased
population or employment, and is not anticipated to result in long-term increases of GHGs. In
addition, the preliminary grading for the future bikeway would help to support the GHG-reduction
measures identified in the City’s CAP, including measures to improve bicycle access and efforts
to achieve a 20 percent bicycle mode share by 2020. The proposed project would also include
the planting of approximately 240 new trees. Over the life of the project, these trees would result
in an increase in carbon sequestration of roughly 170 MTCO2e. For these reasons, this impact
would be considered less than significant.
4.2.6 Cumulative Impacts
The County is currently designated non-attainment for the state ambient air quality standards
(AAQS) for ozone and PM10. Short-term construction-generated emissions of ozone precursor
pollutants (e.g., ROG and NOX) and exhaust PM10 could potentially exceed SLOAPCD
significance thresholds. In addition, fugitive dust generated during construction may result in
localized pollutant concentrations that could result in increased nuisance concerns to nearby
residents. Uncontrolled increases of these construction-generated pollutants could contribute,
on a cumulative basis, to existing non-attainment conditions. Implement of AQ-mm-1 and AQ-
mm-2 would reduce project-specific impacts and the project’s contribution to cumulative impacts
to a less than significant level. Further, all emissions are short-term, and therefore the project
would contribute no emissions once construction is completed. No additional mitigation is
required.
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4.3 Biological Resources
This section evaluates potential impacts to biological resources within the project area. The
analysis considers special-status plant, animal, and vegetation communities as well as impacts
to areas that are located within the jurisdiction of state and federal resource agencies. Potential
short-term and long-term impacts to biological resources are described. For those instances
where potential impacts to sensitive biological resources may occur, mitigation measures and
best management practices have been developed. The San Luis Obispo Creek watershed and
creek system was described in depth in the Waterway Management Plan (WMP) and
Environmental Impact Report/Statement (EIR/EIS), and readers should refer to those
documents for additional setting information. This section focuses specifically on the project
corridor.
4.3.1 Methodology
This section was prepared based on a number of literature reviews and field surveys performed
during preparation of the WMP and subsequent project-specific assessments. The WMP,
Volume 1, Appendix B included a biological resources inventory of each reach of San Luis
Obispo Creek. A project-specific habitat assessment was prepared by the County Public Works
Department in 2010. Once the 30% plans were completed in 2015, an updated literature review
and biological reconnaissance surveys were completed. In addition, recently completed
environmental documents prepared for the Los Osos Valley Road/Highway 101 interchange
project, which is approximately 1.5 miles downstream of the project, were reviewed.
This baseline environmental data was reviewed in the context of the proposed project areas of
disturbance and proposed enhancement activities to identify short and long-term impacts that
could result from the project. Project-proposed mitigation, which is consistent with the best
management practices and other WMP guidance, was then reviewed to determine if it reduced
impacts to a less than significant level. In cases where it did not, additional mitigation is
recommended.
4.3.2 Existing Conditions
The project corridor follows the San Luis Obispo Creek corridor between Marsh Street and
Madonna Road. The corridor has been impacted historically through the construction of
Highway 101, and by the encroachment of commercial and residential land uses along the Mid-
Higuera commercial strip. In some places, this encroachment is literally beyond the top of the
creek bank. In addition, creek bank stabilization in the form of sacrete walls and concrete, are
located along the banks of the creek. The Bianchi Lane Bridge and the Marsh Street Bridge
cross the creek within the project area. A number of culverts discharge into the creek through
the project corridor.
Based on the Natural Resources Conservation Service maps, soils within the project corridor
include Salinas silty clay loam, formed in alluvium weathered from sedimentary rocks. Uplands
in the northwestern portion of the study area are mapped as Los Osos-Diablo complex, which
formed in residual material weathered from sandstone or shale. No serpentine-derived soils are
mapped within the project corridor.
4.3.2.1 WMP Reach 10 Biological Resources Inventory (2002)
The project corridor includes the downstream 75% of what is considered Reach 10 in the WMP.
Reach 10 is described in the WMP as follows:
x land use within this reach is largely urban, with both commercial and residential
development encroaching on the creek corridor;
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x the riparian corridor ranges in width from 15-35 meters, with mixed willows and
eucalyptus dominating the canopy vegetation;
x understory species consist largely of exotics, such as Arundo, castor bean, and cape ivy;
x approximately 92% of Reach 10 is classified as flatwater habitat, with pools and riffles
composing nearly 5% and 3% of the remaining instream habitat areas, respectively;
x the pool frequency ratio was 6.5/km, which represents one of the lowest frequencies
noted within the watershed; and,
x concrete rip-rap and sack revetments, and gabions are abundant along the streambank
at several locations, apparently reflecting attempts to stabilize actively eroding slopes
adjacent to residential and commercial developments.
The inventory identified 13 special-status botanical species that could occur in the watershed –
noting that most are associated with serpentine-derived soils. None of these species were
observed within the reach during spring surveys performed for the WMP. This may be in large
part due to the apparent lack of serpentine-derived soils within the project corridor.
The inventory also identified 13 special-status wildlife species with the potential to occur within
the watershed. Of these, three either have been observed or have the potential to be observed
within Reach 10 - the south-central California coast steelhead, the monarch butterfly, and pallid
bat.
4.3.2.2 Habitat Assessment (2010)
The habitat assessment prepared in 2010 (County of San Luis Obispo 2010) included a review
of CNDDB records, a species list provided by the USFWS and two field surveys, conducted in
May 2010. The surveys identified three primary vegetation communities within the project area,
Riparian Forest, Riverine, and Non-native Annual Grassland. The assessment noted the
dominance of nonnative, invasive species within the understory of the riparian forest habitat.
Based on a list of CNDDB records within the USGS San Luis Obispo quadrangle, the
assessment considered 26 special–status plant species, including all 13 considered in the
original WMP inventory. No special-status plant species were observed during the field surveys.
The habitat assessment confirmed the lack of serpentine soils and outcrops within the project
area.
Thirteen special-status wildlife species were considered in the assessment. Those that have
been observed in the past, and with the potential to occur within the project area include
monarch butterfly, south-central California coast steelhead, pallid bat, Yuma myotis, Cooper’s
hawk, and yellow warbler, as well as numerous species protected by the Migratory Bird Treaty
Act (MBTA) that may nest in the riparian corridor. The assessment concluded that the riparian
habitat along the project corridor was generally of low quality due to a number of factors,
including:
1. much of the native plant cover, especially the understory, has been replaced by non-
native species, many of which are invasive;
2. urban uses occur along the majority of the east bank;
3. non-engineered concrete rubble as well as engineered slope protection exists in many
places, reducing the area of natural stream bank, and failed structures have resulted in
rubble littering the streambed;
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4. there is considerable unauthorized human use of the area, including encampments, with
associated refuse;
5. a minimal amount of adjacent natural upland habitat exists; and
6. Highway 101, just to the west, acts as a barrier to wildlife movement.
4.3.2.3 Vegetation Communities
Biological resources reconnaissance surveys performed in March 2016 confirmed the
conclusions of the 2010 habitat assessment. There are three primary vegetation communities
within the project corridor. They are described below. A complete list of species identified during
the 2010 and 2016 surveys is included in Appendix D. No off-channel or adjacent wetlands were
identified within the project corridor.
Riparian Forest
Riparian forest occurs through much of the project area, and consists of moderate to dense
closed-canopy broadleaf vegetation that closely follows streambank contours. A mixture of
native and non-native plant species characterize the area. Common overstory species include:
arroyo willow (Salix lasiolepis), western sycamore (Platanus racemosa), Fremont cottonwood
(Populus fremontii ssp. fremontii), white alder (Alnus rhombifolia), and non-native blue gum
eucalyptus (Eucalyptus globulus). Understory species include the non-native invasive species
such as elmleaf blackberry (Rubus ulmifolius), cape ivy (Delairea odorata), greater periwinkle
(Vinca major), and garden nasturtium (Tropaeolum majus), as well as native California
blackberry (Rubus ursinus) and mugwort (Artemisia douglasiana). A large stand of mature blue
gum trees occurs at the south end of the project area along the east bank. Mature blue gum
trees are also present on the west side of the Bianchi Lane bridge.
Riverine
Riverine habitat is found within the actively flowing channel, roughly corresponding with the
creek’s ordinary high water mark (OHWM). Seasonally, this habitat type supports emergent
hydrophytes such as watercress (Nasturtium officinale), giant horsetail (Equisetum telmateia
var. braunii) and spearmint (Mentha spicata). Filamentous green algae were found attached to
cobbles and other streambed substrate, especially where sufficient sunlight reaches the water.
Non-native Grassland
Non-native grassland occurs in the proposed Bianchi and South Street bypasses. The dominant
plant species include non-native grasses such as slender wild oat (Avena barbata), Spanish
brome (Bromus madritensis), Harding grass (Phalaris aquatica), Mediterranean barley
(Hordeum marinum ssp. gussoneanum), and mostly non-native annual and perennial herbs,
including Italian thistle (Carduus pycnocephalus), milk thistle (Silybum marianum), and rose
clover (Trifolium hirtum). This community is sparsely vegetated with nonnative forbs, and shrub
species such as coyote brush (Baccharis pilularis). These areas are mowed regularly by the
City of San Luis Obispo to reduce fire risk and control unauthorized use of the open space
properties.
Special-status Plants
In March 2016 a CNNDB search of all plant records within the San Luis Obispo USGS quad
was repeated. The nearest special-status plant occurrences exist 0.25 mile to the southwest of
the project site in the undeveloped South Hills, and approximately 0.5 mile to the west in the
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Laguna Lake area, both of which are associated with serpentine-derived soils. Please refer to
Appendix D for a list of special-status plant species considered in this EIR.
On March 25, 2016 an additional biological resources reconnaissance survey of the project area
was completed. Jurisdictional areas were confirmed and the site was surveyed again for the
presence of special-status botanical and wildlife resources. While the timing of the survey did
not coincide with the blooming periods of all species identified in the CNDDB search, the lack of
serpentine-derived soils, the high level of disturbance, and extensive non-native grassland and
invasive species was confirmed. Consistent with previous survey efforts, no special-status plant
species were observed during the 2016 survey.
4.3.2.4 Special-status Wildlife
In March 2016 a CNDDB search of all special-status wildlife records within the San Luis Obispo
USGS quad was repeated. Please refer to Appendix D for a list of special-status wildlife
considered. Based on the literature review and field surveys, wildlife known to, or with the
potential to occur, within the project area includes the following:
South-central California coast steelhead
Steelhead trout (Oncorhynchus mykiss) are the anadromous form of rainbow trout (McEwan
and Jackson 1996). Steelhead historically ranged from Alaska southward to the California-
Mexico border, though current data suggests that the Ventura River is presently the
southernmost drainage supporting substantial steelhead runs. Periodically, steelhead are
reported within the Santa Clara River and Malibu Creek. Southern steelhead are important in
that they represent the southernmost portion of the native steelhead range in North America,
having ecologically and physiologically adapted to seasonally intermittent coastal California
streams.
Optimal habitat for steelhead throughout its entire range on the Pacific Coast can generally be
characterized by clear, cool water with abundant instream cover (e.g., submerged branches,
rocks, logs), well-vegetated stream margins, relatively stable water flow, and a 1:1 pool-to-riffle
ratio (Raleigh et al. 1984). However, steelhead are occasionally found in reaches of streams
containing habitat which would be considered less than optimal. Steelhead within the central
coast region begin moving up coastal drainages (including San Luis Obispo Creek) following the
first substantial rainfall of the fall season. Spawning typically occurs in the spring in riffle areas
that consist of clean coarse gravels. Deposited eggs incubate for approximately 3 to 4 weeks,
with hatched fry rearing within the gravel intersticies for an additional 2 to 3 weeks. Emergent
fry rear at the stream margins near overhanging vegetation. Juveniles (smolts), after rearing for
1 to 3 years within freshwater, and post-spawning adults out-migrate to the ocean from March to
July, depending on streamflows. Therefore, juvenile steelhead can be found within San Luis
Obispo Creek at all times of the year, while adults are more likely to be found from February to
July.
All populations of steelhead occurring within the South-Central California Coast Distinct
Population Segment (DPS) Region – which is defined as that geographic region north of the
Santa Maria River, northward to (and including) the Pajaro River (and its tributaries), Santa Cruz
County – were listed as Federally Threatened by the National Marine Fisheries Service (NMFS)
in August 1997 and recently reaffirmed by NMFS in their 2015 stock update. Southern
steelhead trout are also considered a California Species of Special Concern. The National
Marine Fisheries Service (NMFS) lists habitat deterioration due to sedimentation and flooding
related to land management practices, and potential genetic interaction with hatchery rainbow
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trout, as risk factors to steelhead within the ESU. This species is protected under the Federal
Endangered Species Act.
San Luis Obispo City Biologist Freddy Otte has previously reported that steelhead spawning
has occurred immediately upstream of the Marsh Street bridge. An individual steelhead and
associated redd were observed immediately upstream of the Madonna Road Bridge in 2009.
Between the Marsh Street Bridge and the Madonna Road Bridge, San Luis Obispo Creek
typically goes dry in the summer. There are several deep pools in the project area that could
support over-summer rearing in a normal winter rainfall regime.
California red-legged frog
California red-legged frog (CRLF) (Rana draytonii) is federally listed as threatened and a state
species of special concern, and is known to occur in central coast watersheds from Point Reyes
National Seashore south to Baja California. Counties that support the greatest number of
occupied drainages include Monterey, San Luis Obispo, and Santa Barbara (USFWS Federal
Register 1996). CRLF require specific habitat characteristics for breeding and upland habitat.
Breeding habitat is characterized by still to slow moving water containing emergent vegetation.
Breeding occurs following large rain events between the months of November and March.
Reddish brown egg masses are laid on emergent vegetation and float at the surface of the
water. Upland habitat is necessary for the survival of this species and includes small mammal
burrows, leaf litter, downed trees, and dense riparian vegetation. CRLF are generally found in
riparian vegetation within 30 meters (100 feet) of a water source, but can move up to 2 miles
between aquatic sites to escape drying areas, forage, or breed (USFWS Federal Register
1996). The project site does not support breeding habitat, but does supports marginal upland
dispersal habitat for this species.
Monarch butterfly
The overwintering habitats for this species are of special concern and protected by the
California Department of Fish and Wildlife. Monarch butterfly uses eucalyptus woodland, as well
as other habitat types for winter roosting. Primary roost sites occur in Montana de Oro and
Morro Bay state parks, scattered areas throughout the communities of Los Osos, Morro Bay,
and Pismo Beach State Park. There are several known aggregation sites within the City of San
Luis Obispo, including in eucalyptus trees at Laguna Lake Park and in oak/eucalyptus woodland
on Cerro San Luis Obispo (County of San Luis Obispo 2010). There is potential for winter
roosting within the project area, although regularly occurring, large aggregations are not
expected and have not been observed, probably due to the project’s inland location and the lack
of large clusters of trees to provide necessary microhabitat conditions (primarily wind protection
and adequate sunlight).
Bats
The site visit on May 10, 2010 revealed evidence of bat roosting beneath the Bianchi Lane
Bridge over San Luis Obispo Creek, but none under the Marsh Street Bridge. No bats were
present at the time of the survey, indicating that the roost is used seasonally or as a night roost.
No day roosting bats were observed under the Bianchi Lane Bridge during a March and August
2016 survey. Three sensitive bat species have the potential to occur within the project area, and
are discussed below. No bats were observed during the biological surveys.
Townsend’s big-eared bat (Corynorhinus townsendii). Townsend’s big-eared bat is a federal
Species of Concern and a California Species of Special Concern. Known to occur in caves, tree
cavities and under bridges; most abundant in mesic (wet) habitats. Potential roosting habitat
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exists within the project area, however because this species is extremely sensitive to
disturbance of roosting sites, roosting is very unlikely. The nearest documented location is on
Camp San Luis Obispo north of Highway 1.
Pallid bat (Antrozous pallidus). Pallid bat is a California Species of Special Concern. It is found
in deserts, grasslands, shrublands and forests. The species is most common in open, dry
habitats with rocky areas for roosting. Potential roosting habitat exists within the Project area,
but pallid bat was not observed during the surveys. The nearest known location is approximately
0.5 mile upstream from the project site.
Yuma myotis (Myotis yumanensis). Yuma myotis is a California Species of Special Concern.
This bat is common and widespread in California, and usually forages over water sources such
as ponds, streams and stock tanks. This species is known to roost in buildings, caves, old
buildings, crevices and in bridges. Potential roosting habitat occurs within the project area.
Avian Species
The San Luis Obispo Creek corridor provides foraging, roosting, and nesting habitat for
numerous avian species, including special-status species such as Cooper’s hawk. Given the
narrow width and disturbed nature of the habitat within the project corridor, the potential for
special-status species to occur is reduced relative to the creek corridor in general. Nevertheless,
species such as Cooper’s hawk and yellow warbler, as well as numerous other migratory birds
are known to occur within the project area. A complete list of wildlife observed during biological
resources surveys is included in Appendix D.
4.3.3 Regulatory Setting
4.3.3.1 Federal Policy and Regulations
National Environmental Policy Act
The National Environmental Policy Act (NEPA) provides a framework for environmental
planning by federal agencies and contains action-forcing procedures to ensure that federal
agency decision makers take environmental factors into account. NEPA applies whenever a
federal agency proposes an action, grants a permit, or agrees to fund or otherwise authorize
any other entity to undertake an action that could possibly affect environmental resources. It is
anticipated that the USACE will act as federal lead agency for this project as they will be issuing
a permit in accordance with Clean Water Act (CWA) requirements.
Section 404 of the Clean Water Act of 1977
The USACE is responsible for the issuance of permits for the placement of dredged or fill
material into “waters of the United States” pursuant to Section 404 of the CWA (33 United
States Code [USC] 1344). As defined by USACE at 33 CFR 328.3(a)(parts 1-6), the following
summarizes “Waters of the United States” as:
“Those waters that are currently used, or were used in the past, or may be susceptible to use in
interstate or foreign commerce, including all waters which are subject to the ebb and flow of the
tide; tributaries and impoundments to such waters; all interstate waters including interstate
wetlands; and territorial seas.”
The project would place fill, in the form of vegetated rock slope protection and cofferdams,
within “waters of the U.S.”, in this case San Luis Obispo Creek. Therefore, the project would be
subject to Section 404 of the CWA.
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Section 401 of the Clean Water Act of 1977
Section 401 of the CWA and its provisions ensure that federally permitted activities comply with
the CWA and state water quality laws. Section 401 is implemented through a review process
that is conducted by the RWQCB, and is triggered by the Section 404 permitting process
described above. The RWQCB certifies via the 401 process that a proposed project complies
with applicable effluent limitations, water quality standards, and other conditions of California
law. Evaluating the effects of the proposed project on both water quality and quantity (runoff)
falls under the jurisdiction of the RWQCB. The proposed project has the potential to result in
impacts to water quality and quantity, and therefore compliance with Section 404 of the CWA.
Therefore, the proposed project would also require compliance with Section 401 of the CWA,
requiring certification by the RWQCB.
Federal Endangered Species Act (FESA)
FESA, administered by the USFWS and NMFS, provides protection to species listed as
threatened or endangered. FESA also provides protection to those species proposed to be
listed under FESA. In addition to the listed species, the Federal government also maintains lists
of species that are neither formally listed nor proposed, but could potentially be listed in the
future. Species on this list receive “special attention” from federal agencies during
environmental review, although they are not protected otherwise under the FESA. The
candidate species include taxa for which substantial information on biological vulnerability and
potential threats exist, and are maintained in order to support the appropriateness of proposing
to list the taxa as an endangered or threatened species. USFWS and NMFS also regulate
activities conducted in federal critical habitat, which are geographic units designated as areas
that support primary habitat constituent elements for listed species.
Due to the presence and/or potential of federally listed species within the project area, including
steelhead and California red-legged frog, compliance with Section 7 of FESA would be required.
Potential impacts to listed species resulting from the implementation of a project would require
the responsible agency or individual to formally consult with the USFWS or NMFS to determine
the extent of impact to a particular species.
Migratory Bird Treaty Act (MBTA)
The MBTA of 1918 protects all migratory birds, including their eggs, nests, and feathers. The
MBTA was originally drafted to put an end to the commercial trade in bird feathers, popular in
the latter part of the 1800’s. The MBTA is enforced by the USFWS, and potential impacts to
species protected under the MBTA are evaluated by the USFWS in consultation with other
federal agencies. Numerous migratory bird species were observed within the project corridor
during surveys.
4.3.3.2 State Policy and Regulations
California Endangered Species Act (CESA)
The CESA ensures legal protection for plants listed as rare or endangered, and wildlife species
formally listed as endangered or threatened. The state also maintains a list of SSCs. SSC status
is assigned to species that have limited distribution, declining populations, diminishing habitat;
or unusual scientific, recreational, or educational value. Under state law, the CDFW is
empowered to review projects for their potential to impact special-status species and their
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habitats. Under CESA, CDFW reserves the right to request the replacement of lost habitat that
is considered important to the continued existence to CESA protected species. Take of state-
listed species would require a Section 2081 Incidental Take Permit from the CDFW. Due to the
lack of state listed species within the project corridor, it is unlikely that a Section 2081 Incidental
Take Permit will be necessary.
California Fish and Game Code
California Fish and Game Code §3511 includes provisions to protect Fully Protected (FP)
species, such as: (1) Prohibiting take or possession "at any time" of the species listed in the
statute, with few exceptions; (2) stating that "no provision of this code or any other law shall be
construed to authorize the issuance of permits or licenses to "take" the species; and (3) stating
that no previously issued permits or licenses for take of the species "shall have any force or
effect" for authorizing take or possession. CDFW is unable to authorize incidental take of "fully
protected" species when activities are proposed in areas inhabited by those species.
Sections 3503 of the Fish and Game Code state that it is “unlawful to take, possess, or destroy
the nest or eggs of any bird, with occasional exceptions.” Section 3503.5 of the Fish and Game
Code states that it is “unlawful to take, possess, or destroy any birds in the order Falconiformes
or Strigiformes (birds of prey) or to take, possess, or destroy the nest of eggs of any such bird
except as otherwise provided by this code or any regulation adopted pursuant thereto.” In
addition, §3513 states that it is unlawful to take or possess any migratory bird as designated in
the MBTA or any part of such migratory birds except as provided by rules and regulations under
provisions of the MBTA. White-tailed kite is a fully protected species under §3511 and has a
potential, albeit a low potential, to occur within the project corridor.
CDFW also manages the California Native Plant Protection Act of 1977 (Fish and Game Code
Section 1900, et seq), which was enacted to identify, designate, and protect rare plants. In
accordance with CDFW guidelines, California Native Plant Society (CNPS) 1B list plants are
considered “rare” under the Act, and are evaluated in CEQA documents.
Section 1602 of the Fish and Game Code
CDFW is responsible for conserving, protecting, and managing California's fish, wildlife, and
native plant resources. To meet this responsibility, the law requires any person, state or local
government agency, or public utility proposing a project that may impact a river, stream, or lake
to notify the CDFW before beginning the project. If the CDFW determines that a project may
adversely affect existing fish and wildlife resources, a Lake or Streambed Alteration Agreement
(SAA) is required. A SAA lists the CDFW conditions of approval relative to the proposed project,
and serves as an agreement between an applicant and the CDFW. As proposed the project
would require a SAA from CDFW.
4.3.4 Significance Criteria
The significance of potential biological impacts is based on Appendix G of the State CEQA
Guidelines. Using these guidelines, activities requiring CEQA review within the project corridor
would have a significant impact on biological resources if they would:
1. Result in a loss of unique or special-status species or their habitats;
2. Reduce the extent, diversity or quality of native or other important vegetation;
3. Impact wetland or riparian habitat;
4. Interfere with the movement of resident or migratory fish or wildlife species, or factors,
which could hinder the normal activities of wildlife; or
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5. Conflict with any regional plans or policies to protect sensitive species, or regulations of
the California Department of Fish & Wildlife or U.S. Fish & Wildlife Service.
4.3.5 Impacts and Mitigation Measures
This section describes impacts related to construction of the project and is organized based on
the significance criteria outlined above and the data provided in the two tables below. Impacts to
vegetation communities are shown in Table BR-1. Temporary impacts would result from all
components of the project including the dewatering, the bridge replacement, the flow return, and
the bypass channels. Installation of the vegetated rock slop protection is considered a
temporary impact.
Table BR-1. Impacts to Vegetation Communities
Vegetation Community Temporary
Impacts
Nonnative grassland/Ruderal 4.09
Riparian Forest 2.38
Riverine 1.56
Total 8.03
Approximately 128 mature native trees would be removed during construction of the project,
primarily at the four benches, as well as at the confluences of the bypass channels and the
creek channel. The species and number of each species to be removed are shown in Table BR-
2. It may be possible to protect some of the trees from impact during construction, but that
cannot be concluded with certainty until much closer to project construction; therefore, this
evaluation assumes that all trees indicated “to be removed” or where “removal may be
necessary” in the project plans (Appendix B), would be removed.
Table BR-2. Tree Removal
Common Name Scientific Name Number
Bay laurel Umbellularia californica 2
California black walnut Juglans californica 16
Coast live oak Quercus agrifolia 7
California sycamore Platanus racemosa 1
Black cottonwood Populus trichocarpa 14
Arroyo willow (primarily) Salix lasiolepis 88
Total 128
Nonnative/ornamental Multiple, primarily
Eucalyptus globulus 24
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Impacts to jurisdictional areas are focused primarily in the areas where bypass channels
intercept the existing creek channel and at the four bench locations. Impacts to jurisdictional
areas are shown in Figure BR-1 and in Table BR-3. Representative photos of the primary
impact areas are included in Appendix D. USACE impact area equals the ordinary high water
mark (OHWM). No other waters of the US were identified within the project area. The CDFW
and RWQCB impact area includes the edge of the San Luis Obispo Creek riparian corridor.
Table BR-3 Impacts to Jurisdictional Features (acres)
Jurisdictional
Feature Project Component Temporary
Impacts
Permanent
Impacts
USACE All areas of the OHWM between 3
sets of dewatering cofferdams 1.56 0.191
Total 1.56 0.00
CDFW /
RWQCB
Bypass channels/vegetated RSP2 1.18 0.191
Benches, Flow Return, Marsh St
sediment removal1 1.20 0.00
3 dewatered areas/OHWM Impacts 1.56 0.00
Bianchi Lane Bridge Center and
Eastern Supports Included above 0.01
Total 3.94 0.20
1. These permanent impacts include the vegetated RSP, root wads and flow deflectors, which would be
considered “beneficial fill”
2. To avoid double counting, this includes areas inside of CDFW/RWQCB jurisdiction but outside of the OHWM.
This EIR includes mitigation measures that are applicable to the project-specific impacts
identified, and have been applied for similar projects, including those in San Luis Obispo Creek
and County. Further, mitigation measures recommended below include as much detail as
applicable at this stage of the process, but it is likely that they will be refined through the
subsequent resource agency permitting process.
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4.3.5.1 Loss of Unique or Special-status Species or their Habitats
4.3.5.1.1 Special-status Wildlife Impacts
A number of special-status wildlife species are known or have the potential to occur within the
project area and would potentially be impacted by project construction. These species are
described below.
California red-legged frog
There are no recorded occurrences of CRLF in CNDDB records for this or neighboring reaches
of San Luis Obispo Creek; however, CRLF has been observed downstream at the City’s Water
Recycling Facility (Caltrans 2008). The proposed project would not impact any potential CRLF
breeding habitat, but may impact foraging habitat and aquatic dispersal/summer habitat. These
impacts may result from dewatering activity and/or from clearing riparian vegetation, which
would result in a temporary loss of potential foraging and dispersal habitat. Construction
activities, which include the use of heavy equipment in and adjacent to riparian habitat, would
potentially impact foraging or dispersing CRLF.
BR-Impact 1 California red-legged frog may be directly impacted during construction
activities.
BR-mm 1 Through the USACE permit process, conduct consultation with the USFWS to
develop avoidance and minimization measures for the CRLF. These measures
may include, for example, the measures described in the 1999 CRLF
Programmatic Biological Opinion between the USFWS and the USACE.
Residual Impact. The Programmatic Biological Opinion (BO) measures referred to in BR-mm 1
are included in Appendix D. The BO measures include pre-construction surveys, identifying
potential relocation sites, and using only qualified biologists to implement the measures.
Implementation of BR-mm 1, will reduce potential direct impacts to a less than significant level.
No additional measures are required.
South-central California Coast Steelhead
This section first describes potential construction-related impacts to steelhead, and then
describes potential longer-term impacts to steelhead habitat within the project area. Within the
project area San Luis Obispo Creek supports rearing habitat for juvenile steelhead, and is a
known migration corridor for adult steelhead and out-migrating juveniles, including steelhead
smolts. Gravel bars present in the vicinity of the project area may support spawning of adult
steelhead, although to what extent adults use this habitat for spawning is unknown.
Construction-Related Impacts to Steelhead
The project could directly impact steelhead during project construction activities occurring in the
wetted (below the OHWM) portion of the channel. Project activities within the channel would
occur in the driest portion of the year, outside of the peak steelhead migration period of March
through May (Caltrans 2008), thereby reducing potential impacts, although some steelhead are
expected to be in the project area during the construction period. Steelhead would potentially be
impacted during the dewatering process as they could be stranded, trapped, or injured during
handling and relocation.
BR-Impact 2 South-central California coast steelhead may be directly impacted during
construction activities.
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BR-mm 2 Construction requiring stream dewatering, stream crossings, or work in the
channel bed will not start before June 1. Upstream and downstream passage for
fish, including juvenile steelhead, will be provided through or around construction
sites at all times. Cofferdams will be installed to divert streamflow around each
in-stream construction area.
BR-mm 3 Through the USACE permit process, conduct consultation with the NMFS to
develop avoidance and minimization measures for steelhead. These measures
may include, for example, having a qualified biologist onsite during the
installation of cofferdams and during the cofferdam dewatering process to
capture and move trapped salmonids and other fish as well as identifying the
appropriate procedures for relocating fish. Protocols for the capture, handling,
and release of fish will be developed in cooperation with NMFS and CDFW and
implemented during project construction.
Residual Impact. Implementation of BR-mm 2 and 3 will reduce potential construction-related
impacts to a less than significant level. No additional measures are required.
Long-term Impacts to Steelhead Habitat
During the environmental review process for the WMP, which included a more general
assessment of potential bypass projects, a number of potential longer-term impacts to steelhead
and their habitat were identified. These included impacts to riparian and upland habitat,
increased erosion and sedimentation, disturbance of spawning gravels, changes in hydrology,
and the potential entrapment of fish in modified/new channels. The EIR/EIS also concluded that
more project-specific environmental review should be performed for capital projects, such as the
proposed project.
NMFS commented on the WMP Draft EIR/EIS, echoed the comments provided on the WMP,
and suggested that channel modification, the creation of new channels, and the use of rip-rap
would potentially reduce channel complexity, and negatively affect the creek’s function and
value as steelhead habitat. The NMFS comment letter is included in the WMP Final EIR/EIS,
which is available for review at the District office. The letter from NMFS recommends that further
environmental analysis should accomplish five things to reduce uncertainties in the steelhead
assessment. Those five things, and a discussion of how they have been addressed, is included
below.
1. Define a system for estimating the number of steelhead that may be affected by project-level
activities.
As described above, assuming implementation of a comprehensive dewatering plan, no fish
mortality is expected to result from construction of the project. There is the potential that if
fish use the bypass channel, they could become stranded in the channel if ponds form as
the water recedes. Fish stranding would be unlikely because the bypass channels would
only be active for limited periods of time. For example, the baseline flow for this stretch of
the creek is 146 cfs. The Bianchi Bypass and South Street Bypass would activate at 1,790
and 440 cfs respectively. During a 2-year storm these bypass channels would flow for
approximately 3.5 and 15 hours respectively. The bypass channels would be active during a
100-year storm for less than 19 hours.
In addition, the bypass channels would be unattractive to migrating steelhead as they
provide little habitat/cover, only function during higher flow events, and they would be sloped
at approximately 2% downstream to discourage ponding. Additionally, habitat improvements
such as scour pools and root wads are proposed at the channel transition areas to
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encourage fish to hold in the main channel. To further avoid potential fish stranding, two
additional mitigation measures are included below. These measures require use of boulder
clusters at the upstream transition areas to provide additional holding habitat in the main
channel, and they require post-storm monitoring of the bypass channels to identify any
potential ponded water and fish that may be stranded.
2. Define a process for measuring the type, quantity, and quality of habitat that is affected by
project-level activities.
During development of the WMP and this Supplemental EIR, the habitat characteristics of
the project area, which is part of Reach 10, were evaluated. As described in section 4.3.2.2,
Reach 10 has one of the lowest pool to riffle ratios in the creek system, is 92% flatwater
habitat, and has an understory largely consisting of non-native, invasive vegetation. Recent
assessments of the area conducted as a part of this Supplemental EIR process confirm that
these conditions remain consistent with those first described in the WMP. Impacts to
jurisdictional areas and vegetation communities as well as mitigation measures that address
those impacts are described in Sections 4.3.5.2 through 4.3.5.4 below. In addition,
mitigation measure BR-mm 7 proposed below requires a quantitative assessment of Reach
10 similar to what was performed for the WMP, be performed prior to construction, and
regularly post-construction. These follow-up assessments would be performed in
coordination with revegetation monitoring. Together these measures would confirm whether
or not the project has had long-term impacts to the biological resources within the project
area.
3. Outline the compensatory mitigation program that will be implemented to offset effects of
project-level activities on steelhead and instream and riparian habitat.
The compensatory mitigation program is outlined in this section of the EIR. It is entirely in-
kind and onsite, and focuses on the replacement of nonnative vegetation with native
vegetation, installation of flow deflectors and rootwads, and utilizes vegetated rip-rap in
places where the use of rock for erosion control and bank stabilization is unavoidable, such
as at bypass channel transition areas. The proposed compensatory mitigation is not based
on typical mitigation “ratios,” but rather, it encompasses a strategy to improve habitat on a
long-term basis.
4. Define a procedure for measuring and detecting spatial and temporal changes in habitat
quality and quantity.
Spatial and temporal changes within the project area may be detected as described above.
Habitat value in the main channel is expected to be improved overall for the reasons
described above (i.e. rootwads, vegetated RSP, removal of invasive vegetation). Further,
the proposed project area includes approximately 75% of the length of Reach 10. By
including the entire reach in follow-up monitoring, the District may gain a better
understanding of unrelated changes in habitat upstream of the project as well.
5. Define a protocol that will track performance of the measures proposed, respond to new
information or changing conditions, and detect and reconcile deficiencies or problems in a
timely manner.
Protocol for tracking the performance of the measures proposed will be developed in the
HMMP, which will be reviewed and approved by the CDFW, RWQCB, and USACE, in
consultation with NMFS and USFWS. HMMPs include performance criteria and outline a
monitoring protocol. In addition, the HMMP will include contingency measures to be
implemented in the event that the proposed measures are not meeting the performance criteria.
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The photo above shows the existing conditions at the proposed upstream end of the Bianchi
Bypass channel from the existing bridge. The figure below illustrates the conceptual root wad
detail that would be installed at this location. The new Bianchi Lane Bridge would be located
upstream from the existing bridge. This area is further described on Sheets C6 in Appendix B of
this EIR.
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BR-Impact 3 Implementation of the project would potentially result in long-term adverse
impacts to the habitat value of the creek for steelhead within the project area.
BR-mm 4 Prior to construction the project plans shall be revised to show the bypass
channels sloped towards the “inside” bank to minimize the potential for ponding
water.
BR-mm 5 Prior to construction the project plans shall incorporate additional boulder
clusters or similar features into the design of the transition areas
BR-mm 6 At the appropriate time following applicable storm events, the bypass channels
shall be inspected to determine the potential for ponded water and to confirm no
fish have been stranded. In the event that special-status fish are observed
stranded in the bypass channels, they shall be relocated by a qualified biologist
consistent with necessary permits and authorizations.
BR-mm 7 Prior to construction and following construction at appropriate intervals, the
habitat assessments consistent with those performed for the WMP shall be
conducted by qualified biologists. These efforts shall be described in and
coordinated with habitat restoration monitoring to be described in the HMMP for
the project.
Residual Impact. Implementation of the measures described above would reduce potential
impacts to less than significant levels. No further measures are required.
Monarch Butterfly
Project construction will include substantial disturbance adjacent to large eucalyptus stands and
the removal of a number of large eucalyptus. No CNDDB records of monarch butterfly
overwintering occur within the project corridor, and large populations were not observed during
biological resources surveys for the project. However, the larger trees and stands potentially
provide habitat for overwintering monarch butterfly.
BR-Impact 4 Removal of larger stands of eucalyptus within the project corridor would
potentially impact overwintering monarch butterflies.
BR-mm 8 To avoid impacts to monarch butterflies, construction shall be avoided as feasible
during the monarch butterfly wintering period (November to February). However,
if work is scheduled to occur during this time, the project corridor shall first be
surveyed for overwintering monarch butterfly. If substantial monarch butterfly
population is observed, tree removal shall cease within 200 feet of the
population, and sufficient dust control measures shall be implemented to
minimize dust emissions and associated impacts to any eucalyptus groves within
or directly adjacent to project-related ground disturbance.
Bats
Various bat species, including special-status bats such as pallid bat and Yuma myotis could use
the Bianchi Lane Bridge as a roosting location; however, no day roosting bats were observed
during biological resources surveys. Crevices in trees onsite could provide roosting habitat for
bat species, as well. Construction includes the demolition of the Bianchi Lane Bridge and tree
removal which could impact roosting bats.
BR Impact 5 Demolition of the Bianchi Lane Bridge and tree removal would potentially impact
roosting bats.
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BR-mm 9 Prior to construction, one daytime and one night-time pre-construction surveys
shall be conducted by qualified biologists no more than 30 days prior to
construction to determine if bats are day or night roosting in the project area. The
biologist(s) conducting the preconstruction surveys will also identify the nature of
the bat utilization of the area (i.e., no roosting, night roost, day roost, maternity
roost). If bats are found to be roosting in the surveyed areas, the following
measures will be implemented during construction:
1. If there is only night roosting by bats and the roost substrate will not be
impacted, work may proceed as normal provided that no night-time work
is scheduled.
2. If there is day roosting by bats (or night roosting and work during
nighttime), qualified biologists shall monitor any construction activities
within 100 ft for disturbance to bat roosting. If bat roosting behavior is
determined to be adversely impacted by construction activities,
construction must be avoided in the vicinity of bat roosts until either bats
are no longer roosting or they have been excluded from roosting.
3. If maternity roosts are detected, construction activities must be avoided
within 100 ft (30 m) of an active maternity roost until the end of the
maternity roosting season (end of September). No roost exclusion shall
be conducted if maternity roosts are detected.
4. Readily visible exclusion zones shall be established in areas where roosts
must be avoided.
BR-mm 10 The design of the new Bianchi Lane Bridge shall incorporate bat friendly features
and/or provide areas where manmade roosts can be easily attached during
construction. If manmade roosts are to be attached to the bridge, this shall be
accomplished prior to the conclusion of construction activities.
Residual Impact. Implementation of BR-mm 5 will reduce potential impacts to bat species to a
less than significant level. No additional measures are required.
4.3.5.1.2 Special-status Plant Impacts
During preparation of the 2010 Habitat Assessment and subsequent follow-up analysis, a
records search was conducted to identify special-status plant species with the potential to occur
within the project site. References included the CNDDB and the Los Osos Valley Road/Highway
101 Interchange environmental documents, which were completed in 2011 for a large project
approximately 1.5 miles downstream. During multiple surveys of the project area for the WMP,
2010 Habitat Assessment, and this EIR, no special-status plant species were identified.
No impacts to special-status plant species would result from the project, and no mitigation is
required.
4.3.5.2 Reduce the Extent, Diversity, or Quality of Native or Other Important Vegetation
As shown in Table BR-1, three vegetation communities would be impacted by the project. Two
of these communities, Riparian Forest and Riverine, could be considered “native and important”
to the function and value of the creek corridor, although as described above, the habitat
provided is of relatively low quality due to the urban encroachment and substantial nonnative
vegetation. As currently proposed, despite the impacts to the vegetation communities above,
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the project is expected to result in improvements to the value of the habitat along San Luis
Obispo Creek. This is due to the following:
x Non-native trees removed during construction would be replaced with native species
x Trash and other debris encountered during construction would be removed.
x Root wads and flow deflectors would be installed within the channel to increase habitat
complexity in the channel by increasing the percentage of pools and riffles within the
reach (refer to Sheet C7 of the project plans).
x Populations of invasive species within the construction area would be removed and all
disturbed areas would be revegetated with native species.
While the area of disturbance is one measure of the temporary impacts resulting from
construction, due to the large percentage of nonnative species that create the understory,
another measure of impacts is the tree removal required for the project. As currently proposed,
the project would result in the removal of up to 152 mature trees. Up to 128 of these trees are
native species, including, but not limited to coast live oak, valley oak, cottonwood, walnut, and
arroyo willow.
The loss of this vegetation during construction will result in a temporary reduction in roosting,
foraging and nesting habitat for birds and other wildlife. The temporary absence of overstory
vegetation will result in impacts to aquatic organisms by reducing shading, increases in water
temperature, and possibly increased algae growth. These impacts are expected to last several
years, with improvement each year, until proposed revegetation matures. In the longer-term, the
reduction in willows along the corridor may reduce the amount of mid-level vegetation available
to birds for foraging, roosting and nesting, and will reduce the numbers of insects available to
animals (including fish) which feed on these invertebrates. Increased penetration of sunlight
may also encourage the proliferation of some undesirable plant species, which in turn could
make native plant restoration more challenging. At the same time, the reduction in non-native
and invasive species, as well as increased channel complexity are considered beneficial
impacts of the project.
Consistent with the long-term management goals of the WMP Drainage Design Manual Figure
11-2 and as shown on Sheet V1, Appendix B of the project plans, willows, as well as any
nonnative tree species, would be replaced with “native, erect, single-trunked species” such as
cottonwood, maple and bay, in order to provide stormwater capacity while enhancing habitat.
Native trees removed by the project would be replaced at an approximately 2:1 ratio and
planted in clusters as shown in Figure 11-2, Appendix B.
BR Impact 6 Project construction will impact approximately 3.94 acres of riparian forest and
riverine communities combined, and result in the removal of approximately 128
native trees, impacting the riparian habitat for wildlife.
BR-mm 11 Prior to construction, the project proponent will retain a qualified biological
monitor(s) to monitor construction and ensure compliance with Avoidance and
Minimization Measures within the project environmental documents.
BR-mm 12 Before any activities begin on a project, a qualified biologist shall conduct a
training session for all construction personnel. At a minimum, the training shall
include a description of the important vegetation and special-status resources
that occur in the project area, the specific measures that are being implemented
to conserve them and the boundaries within which the project may be
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accomplished. Brochures, books, and briefings may be used in the training
session, provided that a qualified person is on hand to answer any questions.
BR-mm 13 During construction, work within the creek shall be conducted when the creek
does not contain flowing or standing water, if feasible. If work activities must
occur when water is present in the creek channel, the contractor shall dewater
the creek prior to conducting the activities.
BR-mm 14 Prior to any construction work beginning, including any vegetation clearing,
sturdy high visibility fencing shall be installed to protect jurisdictional areas and
sensitive resource areas adjacent to the work area. This fencing shall be placed
so that unnecessary impacts to adjacent habitat are avoided. No construction
work (including storage of materials) shall occur outside of the “Project Limits”.
The required fencing shall remain in place during the entire construction period
and maintained as needed by the contractor.
BR-mm 15 During construction, the cleaning and refueling of equipment and vehicles will
occur only within a designated staging area and as far from aquatic areas as
feasible. At a minimum, all equipment and vehicles will be checked and
maintained on a daily basis to ensure proper operation and avoid potential leaks
or spills.
BR-mm 16 During construction, the biological monitor(s) will ensure that the spread or
introduction of invasive exotic plant species is avoided to the maximum extent
possible. When practicable, invasive exotic plants in the project site will be
removed and properly disposed.
BR-mm 17 During construction, trash will be contained, removed from the work site, and
disposed of regularly. Following construction, all trash and construction debris
will be removed from work areas. All vegetation removed from the construction
site shall be taken to a certified landfill to prevent the spread of invasive species.
BR-mm 18 During construction, no pets will be allowed on the construction site.
BR-mm 19 Prior to construction, a comprehensive Habitat Mitigation and Monitoring Plan
(HMMP) shall be prepared that reflects the guidance of the WMP and includes
the following guidelines:
1. Results in an improved pool to riffle ratio, reduction in invasive species, and
increase of canopy cover provided by native species for Reach 10 compared
to the 2002 assessment.
2. A 1:1 replacement ratio for temporary impacts to riverine and riparian
vegetation communities.
3. A 2:1 replacement ratio for permanent impacts to riverine and riparian
communities.
4. A replacement ratio for native trees and shrubs impacted by the project that
will result in equal to or better habitat conditions within the project corridor as
quickly as feasible.
5. Considers invasive species and debris removal in-lieu of a strict tree
replacement ratio where appropriate.
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6. Allows for flexibility in species to be planted so that predominately single-
trunk species such as black walnut, black cottonwood, and bay laurel can be
substituted for willows, for example.
7. Takes advantage of the bypass channels and terraces between the bypass
channels and the creek to replace the ruderal and nonnative annual
grassland vegetation communities with riparian and native upland ones, even
in areas not directly impacted by the project construction.
BR-mm 20 During construction, the project will make all reasonable efforts to limit the use of
imported rock. Imported material should be obtained from a source that is known
to be free of invasive plant species; or the material must consist of purchased
clean material such as crushed aggregate, sorted rock, or similar.
Residual Impact. Implementation of BR-mm 7 through BR-mm 16, along with the development
of plans such as the Dewatering and Diversion Plan, the Spill Prevention and Control
Contingency Plan, and the Stormwater Pollution Prevention Plan which will all be prepared
subsequently, will reduce potential impacts to important natural communities to a less than
significant level. No additional measures are required.
4.3.5.3 Impact Wetland or Riparian Habitat
San Luis Obispo Creek is a perennial stream and would be considered “other waters” by the
USACE. The area of other waters corresponds with the Riverine vegetation community
described above, and the OHWM of the creek. During surveys for the project no off-channel,
adjacent, or other wetlands were observed. Impacts to the other waters and Riparian Habitat
are also described above.
4.3.5.4 Interfere with the Movement of Resident or Migratory Fish or Wildlife Species, or
Factors, which Could Hinder the Normal Activities of Wildlife?
Potential impacts to fish and other wildlife have been described previously. To avoid
redundancy, this section includes only a discussion of migratory avian species. Several special-
status avian species such as Cooper’s hawk and non–sensitive migratory birds could nest in
and adjacent to the project area. A complete list of avian species observed during biological
resource surveys is included in Appendix D. The breeding season for most birds is generally
from February 15 to September 1, peaking from April through June, with exceptions. Cooper’s
hawk is designated as a state species of special concern. Construction is expected to begin in
the dry season, approximately April 15 at the earliest. Birds nesting in the project corridor could
be disturbed by the noise, dust and similar disturbances such that they abandon a nest. Further,
nests could be directly impacted during tree removal, grading, and similar activities.
BR-Impact 7 Construction activities would result in impacts to nesting avian species
BR-mm 21 To protect special-status avian species and those species protected by the
MBTA, the District shall avoid vegetation clearing and earth disturbance during
the typical nesting season (February 15 to September 1). If avoiding construction
during this season is not feasible, a qualified biologist shall survey the area within
one week prior to activity beginning on site. If nesting birds are located on or near
the proposed project site, they shall be avoided until they have successfully
fledged. A buffer zone of 50 feet will be placed around all non-sensitive,
passerine bird species, and a 250-foot buffer will be implemented for raptor
species, and all activity will remain outside of that buffer until the qualified
biologist has determined that the young have fledged. Buffer reductions and/or
work within non-disturbance buffer areas can be completed only with approval
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from relevant resource agencies.
Residual Impact. Implementation of BR-mm 16 will reduce potential impacts to a less than a
significant level. Measures BR-6 through 15 will reduce indirect impacts and short-term impacts
to vegetation in the project corridor that may be used as habitat for nesting birds to a less than
significant level. No additional measures are required.
4.3.5.5 Conflict with any Regional Plans or Policies to Protect Sensitive Species, or
Regulations of the California Department of Fish & Wildlife or U.S. Fish & Wildlife
Service
Critical habitat was redesignated for south-central California coast steelhead by NOAA Fisheries
(70 FR 52574, September 2, 2005). San Luis Obispo Creek is included in the critical habitat
designation. As described above, the project would potentially directly impact steelhead during
dewatering operations, and result in potential indirect temporary impacts through the short-term
loss of riparian and riverine habitat, resulting in secondary in this habitat. Potential impacts and
mitigation is described above. No additional mitigation is required.
4.3.6 Cumulative Impacts
Implementation of the Waterway Management Plan as well as the other projects identified in the
Cumulative Development Scenario, when considered along with the proposed project, could
have a significantly cumulative impact to the San Luis Obispo Creek watershed. These impacts
include the temporary loss of riparian vegetation, use of heavy equipment within the riparian
corridor, and in some cases the low-flow channel, as well as possible indirect impacts to wildlife
along the corridor through the introduction of additional recreational uses within the corridor.
However, projects that potentially directly affect San Luis Obispo Creek are generally highly
regulated. The proposed project would require permits or other authorizations from regulatory
agencies including the USACE, RWQCB, CDFW, USFWS, and NMFS. These agencies are
responsible to authorize projects that avoid, minimize, and/or mitigate impacts to habitats,
jurisdictional waters, and sensitive plant and wildlife species. The projects listed in the
cumulative development scenario are also potentially subject to regulations by all of these
agencies.
In addition, there are ongoing efforts by the City of San Luis Obispo, and the San Luis Obispo
Land Conservancy to improve habitat value within the creek watershed – the ongoing Arundo
removal projects, for example, as well as the upgrade to the City’s Water Recycling Facility.
These projects, along with the propped project enhancement activities will result in cumulative
beneficial impacts to the watershed and the species potentially impacted by the proposed
project, including the CRLF and steelhead. As a result, no mitigation beyond that already
discussed in this EIR is required to address the project’s potential contribution to cumulative
impacts.
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4.4 Cultural Resources
This section describes potential impacts to cultural (historic and/or prehistoric) resources that
may result from the project. The information that follows relies primarily on two documents, the
EIR/EIS and the Archaeological Survey Report (ASR) prepared for the project (County of San
Luis Obispo 2011).
4.4.1 Methodology
The ASR prepared for the project included a records search and a pedestrian survey. The
records search was conducted for all known archaeological sites, historic resources, and
surveys within the project corridor (referred to as the Area of Potential Effect [APE] in the ASR).
A search of the inventories for the State Historic Property Data Files, National Register of
Historical Landmarks, California Points of Historic Interest, California OHP Archaeological
Determinations of Eligibility, and the Caltrans State and Local Bridge Surveys yielded six
property evaluations within the search radius.
The records search revealed that much of the corridor has previously been subject to cultural
resources surveys between 1978 and 2008. Several surveys have been conducted along South
Higuera Street, and one focused on Highway 101’s right of way through the length of th e project
area. The creek banks have also been surveyed, twice. In all, 25 surveys have been conducted
and five historic properties have been recorded within the search area. No prehistoric sites have
been recorded in the project corridor.
The project corridor was visually inspected on May 5, and May 10, 2010. The limits of the APE
were surveyed in several meandering transects, focusing on bare soils and exposed creek
banks. All bare soils and gopher burrows were inspected for the presence of cultural materials.
Ground surface visibility varied between completely obscured (asphalt areas) and approximately
30%. The majority of the survey area consisted of non-native annual grassland and riparian
vegetation. Survey of the creek banks was obscured by sacrete and rubble walls, and dense
riparian vegetation.
4.4.2 Existing Conditions
The project area was prehistorically inhabited by the Obispeño Chumash. The Chumash and
their ancestors have inhabited San Luis Obispo County for at least 10,000 years (Greenwood
1972; Fitzgerald et al. 1998). The Northern Chumash, or Obispeño, are the northernmost
Chumash speaking peoples of California and ranged from the Pacific Coast east to the coastal
ranges and from the Santa Maria River north to San Simeon or beyond.
The Chumash developed a complex system of social organization rarely observed in other
hunting and gathering groups in the world. The Obispeño were hunter-gatherer-fishers who
resided in both ephemeral camps and permanent villages. Many of the coastal sites are easily
identifiable due to their high density of shellfish remains while many of the interior sites
(including sites in the project vicinity) are identified predominantly through the presence of
flaked stone tool manufacture remains. The Chumash were adept at recovering not only
shellfish, but also hunted small and large game, waterfowl, and gathered a large assortment of
plants including acorns as a staple food. The Chumash are also world-renown for their
elaborate basketry.
After the Mission system was established in 1772 in San Luis Obispo and soon after in Santa
Barbara, Santa Inez, San Buenaventura, and La Purisima, Chumash populations immediately
declined, resulting in near extinction of the people by the early 1900s. Today, descendants of
these groups continue to live in San Luis Obispo, Santa Barbara, and Ventura Counties.
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The historic period begins with Spanish exploration of California in 1542. In 1822, California
became a Mexican territory and the lands of the Mission were secularized and disbanded by
1834. The County of San Luis Obispo was established in 1850, and at that time, the area to
become the City of San Luis Obispo consisted of approximately 150 buildings. The City was
incorporated in 1876. Also in 1876, the San Luis Obispo and Santa Maria railroad was
completed between Port San Luis (then called Port Harford) and the City. The Pacific Coast
Railroad terminal was located near the intersection of South Higuera and South Streets, just
east of the project corridor. The railroad operated a roundhouse and warehouses until the
1930s. The San Luis Lumber company was serviced by the railroad and occupied the entire
block bounded by Higuera, Beebee, South, and High Streets.
The Smith and Waites Planing Mill and Machine Shop was established in 1883 where Haywood
Lumber currently exists northwest of the intersection of South Higuera Street and South Street
east of the creek. Construction of the railroads brought immigrants from China and Great
Britain. Dairying was an important industry in the County in the early 20th century, attracting
farmers of Italian-Swiss descent.
Later, Japanese farm laborers arrived to the City, and settled in the area of lower Higuera, at
South Street. A cluster of six wood frame houses on Brook Street constitute the only remaining
farm labor camp in the City. This area, in the 1930's, was referred to as the "Japanese Village"
and on the pre-1957 Sanborn maps, Brook Street was known as Eto Street. South Higuera
Street served as major thoroughfare even after the Pacific Coast Railroad was closed. Higuera
was (and still is today) lined with automobile repair shops and service stations. Over time, the
Mid-Higuera Street corridor between Madonna and Marsh became less residential and more
industrial. Today, very few homes remain in this area.
Figure CR-1 – Birds Eye View of San Luis Obispo, 1877
Approximate Flow Return Area
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4.4.3 Regulatory Setting
4.4.3.1 State Regulations
California Environmental Quality Act
CEQA (Public Resources Code 21000 et seq.) requires lead agencies to consider the potential
effects of a project on significant historical and archaeological resources. Significant impacts on
such resources are to be avoided or mitigated to less than significant levels. Other state laws
govern actions affecting cemeteries and human remains.
State historic preservation regulations affecting this project include the statutes and guidelines
contained in CEQA (Public Resources Code Sections 21083.2 and 21084.1 and Section
15064.5 of the CEQA guidelines). CEQA requires lead agencies to carefully consider the
potential effects of a project on historical resources. CEQA Guidelines provides criteria for
determining the significance of a cultural resource. This section states the following:
“Generally, a resource shall be considered by the lead agency to be “historically significant” i f
the resource meets the criteria for listing on the California Register of Historical Resources
(Pub. Res. Code §5024.1, Title 14 CCR, Section 4852) including the following:
(A) Is associated with events that have made a significant contribution to the broad
patterns of California’s history and cultural heritage;
(B) Is associated with the lives of persons important in our past;
(C) Embodies the distinctive characteristics of a type, period, region, or method of
construction, or represents the work of an important creative individual, or possesses
high artistic values; or
(D) Has yielded, or may be likely to yield, information important in prehistory or history.”
Assembly Bill 52
With passage of Assembly Bill 52 the State of California recognized, among other things, that:
“California Native American tribes may have expertise with regard to their tribal history and
practices, which concern the tribal cultural resources with which they are traditionally and
culturally affiliated. Because the California Environmental Quality Act calls for a sufficient degree
of analysis, tribal knowledge about the land and tribal cultural resources at issue should be
included in environmental assessments for projects that may have a significant impact on those
resources.”
AB 52 therefore requires lead agencies to begin consultation with a California Native American
tribe that is traditionally and culturally affiliated with the geographic area prior to the release of a
negative declaration, mitigated negative declaration, or environmental impact report for a
project. When responding to the lead agency, the California Native American tribe shall
designate a lead contact person. California Native American tribes have 30 days to request
consultation regarding possible significant effects that implementation of the proposed project
may have on tribal cultural resources. AB 52 notifications began on January 6, 2016. The
response period concluded on February 8, 2016. A number of responses were received,
however, no previously unknown resources were identified by respondents.
4.4.3.2 City of San Luis Obispo Regulations
The City of San Luis Obispo General Plan, Conservation and Open Space Element (2006)
includes a number of policies intended to preserve cultural resources. These polices include:
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3.5.4. Archaeologically sensitive areas. Development within an archaeologically sensitive area
shall require a preliminary site survey by a qualified archaeologist knowledgeable in Native
American cultures, prior to a determination of the potential environmental impacts of the project.
3.5.5. Archaeological resources present. Where a preliminary site survey finds substantial
archaeological resources, before permitting construction, the City shall require a mitigation plan
to protect the resources. Possible mitigation measures include: presence of a qualified
professional during initial grading or trenching; project redesign; covering with a layer of fill;
excavation, removal and curation in an appropriate facility under the direction of a qualified
professional.
3.5.6. Qualified archaeologist present. Where substantial archaeological resources are
discovered during construction or grading activities, all such activities in the immediate area of
the find shall cease until a qualified archaeologist knowledgeable in Native American cultures
can determine the significance of the resource and recommend alternative mitigation measures.
3.5.7. Native American participation. Native American participation shall be included in the City's
guidelines for resource assessment and impact mitigation. Native American representatives
should be present during archaeological excavation and during construction in an area likely to
contain cultural resources. The Native American community shall be consulted as knowledge of
cultural resources expands and as the City considers updates or significant changes to its
General Plan.
4.4.4 Significance Criteria
Appendix G of the CEQA Guidelines provides guidance in determining a project's impact on
cultural resources. This guidance has been used to develop the significance criteria for cultural
resources. Specifically, the project would have a significant impact on cultural resources if:
1. The project causes a substantial adverse change in the significance of an historical
resource. This would include physical demolition, destruction, relocation, or alteration of
the resource or its immediate surroundings such that the significance of an historical
resource would be materially impaired;
2. The project causes a substantial adverse change in the significance of an archaeological
resource;
3. If the project directly or indirectly destroys a unique paleontological resource or site or
unique geologic feature; or
4. If the project disturbs any human remains, including those interred outside of formal
cemeteries.
The project will disturb recent alluvium deposits and therefore no paleontological resources
would be impacted. Further, there are no impacts expected to human remains. The section that
follows considers historic and prehistoric resources.
4.4.5 Impacts and Mitigation Measures
This section describes potential impacts and is organized based on the significance criteria #1
and #2 outlined above.
4.4.6 The project causes a substantial adverse change in the significance of an
historical resource
The potential for encountering buried historical deposits is high throughout the project area, but
especially at the Marsh Street terrace. Evaluation of other projects in the vicinity have yielded
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buried historical trash dumps along the creek. The discussion of impacts and mitigation
measures that follows is focused on historical resources and organized by project component,
or sub-component, as applicable. The place names in the ASR and the current project
description vary at times, so names are cross-referenced in parentheses, as necessary.
Flow Return (Marsh Street Terrace)
The Flow Return component is the most sensitive area for buried historical resources. The
project would include excavating the majority of the northern half of the parcel to construct the
flow return. Excavation would occur from the eastern edge of the parcel to approximately the
bank of the creek, where additional grading for a creek bench would occur.
The location is currently undeveloped; however, Sanborn Fire Insurance maps show that this
was a residential neighborhood on the fringe of the railway district beginning with the first
structure dating to at least 1891. Over the next 100 years, the following residences and
businesses existed on these lots: residences (1891, 1909, 1926, 1930’s-1940’s), automobile
service station, auto repair shop (1926, on “pilings over the creek”), stone cutting business
(1931), leather shop, possible restaurant, beer warehouse, laundry facility, auto repair,
motorcycle repair shop, and a plumbing business. Further, a structure can be seen in this
location on the 1877 “Birds Eye View of San Luis Obispo” (refer to Figure CR-1) that was
demolished by the time the 1891 Sanborn map was drawn.
At the turn of the century, trash pits and privies would have been located away from the homes,
toward the creek banks. Significant intact, but buried, deposits may be encountered during
construction.
Pinch Point (Madonna Bench)
This portion of the project would involve the excavation of the creek banks on both sides of the
creek, up to approximately 240 feet on the western side. When the ASR was prepared, the
project included construction of a bench, approximately 7 feet in depth, on the western creek
bank, only, although it would span from the Marsh Street Bridge to the Bianchi Lane Bridge,
which is approximately 640 feet. The area close to Bianchi Lane has been determined to be
sensitive in the past for historic resources.
Bianchi Bypass (Bianchi Lane Terrace)
This portion of the project is located on the west side of the creek and would involve
construction of the bypass channel approximately 6 to 8 feet deep from the Bianchi Lane Bridge
south approximately 800 feet. The Bianchi Bypass includes two City-owned open space parcels
that are located between Highway 101 and the creek. No structures are currently on the
property. Sanborn maps did not cover this area. Historical aerials from 1937 show this area as
undeveloped. The 1949 aerial shows grading or fill at this location, likely related to the
construction of Highway 101. Surface survey revealed only modern trash related to homeless
encampments along the creek bank.
Bianchi Lane Bridge
The Bianchi Lane Bridge is a single-span steel bridge with a date stamp of 1905. This bridge
was originally a railroad bridge near Elks Lane that was converted to an automobile bridge and
moved to its current location around 1940. It was evaluated by Caltrans for National Register
significance and found to be ineligible.
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South Street Bench
This portion of the project would involve the construction of a bench, approximately 8 feet deep
and 200 feet long, located on a narrow strip of City-owned open space property that is located
between the creek and the Hayward Lumber Yard at the western end of South Street. This
specific area is not covered by the Sanborn maps, but areas immediately to the east are. A
small dwelling was located on the north side of South Street approximately 100 meters east of
San Luis Obispo Creek in 1888. Trash dumps associated with this structure may be found
buried closer to the creek. The commercial property immediately adjacent to this proposed
bench was surveyed in 1998 and did not show any surface indications of cultural resources. A
buried historical trash dump was previously discovered at the end of South Street just about 10
meters south of this bench location.
South Street Bypass
The South Street Bypass would be approximately 10 feet deep and 600 feet long, parallel to
and west of the existing creek. The South Street Bypass is situated on City-owned open space
property located between Highway 101 and the creek. The west side of the creek is generally
less sensitive than the east, where the commercial development and railway yard were located.
There is no evidence from the historical aerial photographs dating back to 1937 that this parcel
was ever developed. This area appears to be heavily impacted (and possibly filled) from the
construction of Highway 101.
Impact CR-1 Excavation of the project components, including, but not limited to the Flow
Return, the Pinch Point, and the Bypass channels, have the potential to impact
buried historical resources.
CR-mm-1 Prior to construction, a detailed excavation and monitoring plan shall be prepared
and implemented by a qualified historical archaeologist. The monitoring plan
should specify the following:
1. A description of preconstruction exploratory excavations at the Flow Return;
2. A description of how and where the monitoring will occur;
3. Description of monitoring intensity at different project locations;
4. A description of the resources anticipated to be discovered;
5. A description of the circumstances under which construction will be halted;
6. Description of the procedures to be followed in the event significant resources
are found;
7. Personnel involved in monitoring activities; and
8. Arrangements for curation and a description of those materials that would
qualify for curation.
9. Procedures to be implemented in the event there is an unanticipated
historical or prehistoric discovered within the project area during construction
to ensure compliance with State and local code.
Residual Impact. After implementation of MMCR-1, residual impacts to cultural and
paleontological resources would be less than significant.
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4.4.7 The project causes a substantial adverse change in the significance of an
archaeological resource.
No prehistoric archaeological sites were discovered in the project’s APE. Furthermore, the
project excavation areas are located within the creek banks that would have been active
floodplain (and therefore, unattractive for human settlement) until channelization by urban uses.
The potential for prehistoric buried resources is very low in this area. No impacts will result from
the project and no measures other than those already required by City code are required.
4.4.8 Cumulative Impacts
Implementation of the proposed project, combined with other reasonably foreseeable projects
within the creek watershed could result in the cumulative discovery and/or disturbance of
cultural resources. Redevelopment of the Mid-Higuera corridor could impact cultural resources.
The proposed project would not impact any known prehistoric resources and therefore would
not contribute to cumulative impacts to prehistoric resources.
The project would potentially impact historic resources, although mitigation measures have
been recommended to reduce project-specific impacts to less than significant levels. This, along
with the cultural resources avoidance and minimization measures in the WMP, the Mid-Higuera
Enhancement Plan, and in the City’s General Plan and codes which would be applied to future
projects, ensure that the proposed project would have a less than significant cumulative
contribution to cultural resources.
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4.5 Hazards and Hazardous Materials
This sections describes the hazards and hazardous materials conditions that may affect or be
affected by the project. The information in this section summarizes three reports prepared for
the project, including the Phase I Environmental Site Assessment and Preliminary Phase II
Subsurface Assessment Activities for Properties Associated with Proposed Mid-Higuera By-
Pass Project (Padre 2010), and the Report of Findings of the Supplemental Soil Assessment
Activities for the Mid-Higuera Bypass Project (Padre 2016). These documents are available for
review in their entirety from the District.
4.5.1 Existing Conditions
4.5.1.1 Phase I Environmental Site Assessment Results
The objective of the Phase I Environmental Site Assessment (Phase I) prepared for the project
was to
“…evaluate whether current or previous land use at or adjacent to the Project Site may have
involved, or resulted in the use, storage, disposal, treatment, and/or release of hazardous
substances to the environment, resulting in the determination of a Recognized Environmental
Condition (REC) associated with the various the Project Site properties.”
A REC is defined by ASTM E-1527-05 as the presence or likely presence of any hazardous
substance or petroleum products on a property under conditions that indicate an existing
release, a past release, or a material threat of release of any hazardous substances or
petroleum products into structures on the property or into ground, groundwater, or surface water
of the property.
After a review of available resources, the following conclusions were made regarding the
potential for the presence of hazardous materials within the project area. In some cases,
different terms were used for the project components. In these cases, the current name is
provided first and the name used in the technical report is included in parentheses.
Flow Return (Marsh Street Terrace)
A former gasoline service station was located on a portion of this component from the 1950s to
the 1990s. The property had three underground storage tanks (USTs), which were removed in
the 1980s; however, supporting documentation was not available regarding the soil conditions
surrounding the USTs upon removal. Additionally, other portions of this component (between
316 and 350 Higuera Street) have historically been occupied by auto repair facilities, a possible
dry cleaner/laundry facility, and a stone cutting business (circa 1920s). Off-site uses that could
affect this component include a former PG&E substation with a listed open Leaking UST case,
and a former manufactured gas plant with continuing investigation/remediation pending. Both of
these uses were located immediately east of the Flow Return, across Higuera Street.
Madonna Bench
This bench would be excavated on the eastern side of the Madonna Construction Yard property,
between the channel and the structures. The property has maintained up to four USTs through
the early 2000s, and a closed LUST case was documented for the properly. Additionally, the
aboveground storage of numerous types of chemicals and petroleum products has been
documented, and the property was generally used as a heavy equipment construction and
maintenance yard circa 1950s to the present.
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Bianchi Bypass and Bridge (Bianchi Lane Terrace)
Based on a review of aerial photographs, it appears that undocumented fill material may have
been placed in the area of the proposed bypass. Additionally, the Bianchi Bridge and Bypass
area appears to have been used as a heavy construction equipment storage area associated
with the Madonna Construction Yard.
South Street Bypass and Bench
The proposed bench between the Bianchi Bypass and South Street Bypass is located
immediately adjacent to a listed UST and closed LUST case (34 South Street). The LUST was
removed, impacted soil was remediated, and the LUST case was closed with the SLO Fire
Department. Additionally, this property was documented to have been a laundry facility or
uniform care service facility prior to the 1990s. The northern-most area of the bench South
Street Bench is also located adjacent to a property known to have maintained an “oil shack” with
shallow soil documented to contain petroleum hydrocarbons exceeding SLO Fire Department
cleanup goals. However, the oil shack and the shallow soil in the area were reportedly removed
approximately 15 to 20 years ago. The Phase I did not identify any potentially hazardous
conditions associated with the properties included as part of the South Street Bypass.
4.5.1.2 Preliminary Phase II Environmental Site Assessment Results
In an effort to better characterize the potential hazardous materials issues in the project area
identified in the Phase I, the County proceeded with preliminary Phase II (subsurface sampling)
hazardous materials assessment. The preliminary Phase II work included the development of
the nine direct-push drill holes, seven hand augured drill holes, and the collection of several soil
samples from the surface/shallow soil zone. The results of the preliminary Phase II work are
summarized below:
Flow Return
A total of 11 drill holes were advanced in this area to assess subsurface soils for the presence
of petroleum hydrocarbons associated with a former gasoline service station and those that may
presence or evidence of impacts that may be associated with past industrial activities, auto
repair shops, and possible laundry/dry cleaning facility. Based on the analytical results and field
observations, there was no indication of fuel or waste oil releases to the subsurface soil from the
former gasoline station USTs or associated product piping.
At one drill hole on the southern portion of this component (HA -3), an approximately 1-foot layer
of black sandy soil with ash or slag and brick fragments was encountered beginning at a depth
of 2 feet below surface at drill hole location HA-3. Soil samples collected indicated
concentrations of PAHs exceeding the Residential RSLs and TPH exceeding SLOFD cleanup
goals. The vertical extent of PAH and TPH-containing soil within drill hole HA-3 is estimated to
approximately 3 feet below surface. The lateral extent of the ash/slag layer could not be
evaluated during the assessment.
Madonna Bench
Four shallow zone (within upper 1-foot) soil samples were collected and chemically analyzed to
evaluate for the presence of petroleum hydrocarbons and California-regulated metals
associated with historical chemical use and storage and the maintenance of construction
equipment at this area of the project site. TPH was indicated in all four samples at
concentrations exceeding the SLOFD action level of 100 mg/kg. Additionally, soluble lead was
indicated at a concentration exceeding the STLC, which renders the soil as California
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Hazardous for disposal criteria should the soil be disposed at a landfill. The vertical and lateral
extents of TPH and STLC lead containing soil were not characterized.
Bianchi Bypass and Bridge (Bianchi Lane Terrace)
Based on the field observations and analytical results from five collected soil samples, TPH was
indicated at a concentration exceeding the SLOFD action level in one sample collected at a
depth of two feet below surface. The sole, shallow zone TPH concentration detection may have
been a result of asphalt debris associated with an old, weathered asphalt road observed within
the area assessed.
South Street Bench
Two drill holes were advanced within this area of the project site. Based on the field
observations, there was no indication of TPH-containing soil at the drill hole locations. A third
drill hole originally proposed was not advanced because upon further review, the proposed the
bench area would not extend into the area of the former “oil shack” on the adjacent property to
the north.
Lead and Naturally Occurring Asbestos Sampling
Surface soil samples were collected near Hwy 101 on the northern-most area of the South
Street Bypass and within the Bianchi Lane Bypass nearest Hwy 101. The samples were
chemically analyzed for lead and naturally occurring asbestos. The lead concentrations did not
exceed the Residential RSL and asbestos was not detected in the two samples collected.
4.5.1.3 Subsequent Phase II Environmental Site Assessment Results
In April 2016 a subsequent Phase II environmental assessment was performed. The intent of
the subsequent assessment was to further characterize the lateral and vertical extent of
chemicals of potential concern (COPC) in two project areas, the Flow Return Area and the north
end of the Bianchi Bypass. A total of 15 drill holes were made and soil samples collected for
testing at appropriate depths. Forty-three soil samples were collected.
Flow Return Area
Subsurface soil encountered in this area primarily consisted of fill material including large
granitic gravel, concrete debris, brick, and asphaltic clasts contained within a sandy soil. The
large gravel and concrete debris made it impossible to advance the manual hand auger drill
below one to two feet at the locations of several drill holes.
COPCs identified at the Flow Return Area include lead and several PAH constituents within the
upper three to five feet of soil and laterally distributed across most of the area, including the
proposed bench area.
Lead, at concentrations in excess of the ESL, is located primarily within the northwestern area
of the proposed flow return and the northern portion of the proposed bench, with the maximum
vertical extent estimated at a depth of approximately four feet at both areas. Lead, at
concentrations in excess of the TTLC and/or the STLC (California-hazardous), was identified
within the northwestern area of the proposed flow return and northeastern area of the proposed
bench.
PAH constituents exceeding the ESLs are generally widespread throughout both the flow return
and bench areas. The estimated average depth of the contamination is approximately three feet
at both the flow return and bench areas. However, the vertical extent was not defined at the
location of eight drill holes advanced at both the flow return and bench areas due to concrete
and/or large gravel encountered during the course of the hand-auger.
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Based on the preliminary and subject supplemental assessment data, the report concluded that
approximately 1,810 cubic yards of soil are impacted with PAH constituents and lead
concentrations exceeding their respective ESLs. Of the estimated 1,810 cubic yards,
approximately 460 cubic yards of soil are additionally impacted with lead exceeding the TTLC
and/or STLC values and would be classified as California-hazardous waste for disposal
purposes.
Bianchi Bypass/Bridge
A total of eight soil samples were chemically analyzed for the presence of TPH (diesel fuel and
motor oil ranges) from this area. None of the soil samples with reportable concentrations of TPH
(both diesel fuel and motor oil ranges) exceeded the respective ESLs. A total of eight soil
samples collected were chemically analyzed for the presence of California-regulated metals.
None of the eight soil samples chemically analyzed for California-regulated metals were
indicated in excess of their respective established TTLC concentration. A total of seven soil
samples were further chemically analyzed by STLC and/or TCLP methods for soluble chromium
and/or nickel. Soluble chromium and nickel concentrations did not exceed their respective STLC
values.
4.5.2 Regulatory Setting
Hazards and hazardous material management is subject to multiple laws, policies, and
regulations at all levels of government. The agencies responsible for enforcing applicable laws
and regulations develop and enforce standards for the handling and cleanup of specific
materials determined to pose a risk to human health or the environment. The enforcing agency
at the local level for the proposed project area is San Luis Obispo County Health Agency,
Division of Environmental Health. Enforcement agencies at the State level include two branches
of the California Environmental Protection Agency (CalEPA), the Department of Toxic
Substances Control (DTSC), and the RWQCB. The Federal enforcement agency is the EPA. A
description of agency involvement in management of hazardous materials is provided below.
4.5.2.1 Federal Policies and Regulations
The EPA is the Federal agency responsible for enforcement and implementation of federal laws
and regulations pertaining to hazardous materials; in addition, the EPA provides oversight and
supervision for some site investigation/remediation projects. For disposal of certain hazardous
wastes, the EPA has developed land disposal restrictions and treatment standards. Legislation
includes the Resources Conservation and Recovery Act of 1986 (RCRA), the Superfund
Amendments and Reauthorization Act of 1986 (SARA), and the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA). The Federal regulations are
primarily codified in Title 40 of the Code of Federal Regulations (CFR). These laws and
regulations include specific requirements for facilities that handle, generate, use, store, treat,
transport, and/or dispose of hazardous materials, as well as for investigation and cleanup of
contaminated property.
4.5.2.2 State Policies and Regulations
Regional Water Quality Control Board
The project site is located within the jurisdiction of the Central Coast RWQCB. The RWQCB is
authorized by the California Porter-Cologne Water Quality Act of 1969 (“the Porter-Cologne
Act”), to implement water quality protection laws. When the quality of the groundwater or the
surface waters of the State is threatened, the RWQCB has the authority to require investigations
and remedial actions. In addition, the Central Coast RWQCB is the State regulatory agency that
oversees the local Leaking Underground Fuel Tank (LUFT) program, which was established to
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regulate underground fuel tanks. Under the LUFT program, local implementing agencies are
required to permit, inspect, and oversee monitoring programs to detect leakage of hazardous
materials.
Department of Toxic Substances Control (DTSC)
In California, the DTSC, a branch of CalEPA, works in conjunction with, or in lieu of, the EPA to
enforce and implement specific hazardous materials laws and regulations. California has
enacted its own legislation pertaining to the management of hazardous materials.
California Occupational Safety and Health Agency
Worker health and safety in California is regulated by the Department of Industrial Relations,
Division of Occupational Safety and Health (Cal/OSHA). Cal/OSHA standards and practices for
workers dealing with hazardous materials are contained in Title 8 of the CCR, and include
Division 1, Chapter 4, Subchapter 7 (General Industry Safety Orders) and Section 5192.
Hazardous Waste and Substance Site List (Cortese List)
The Cortese List is a compilation by the State of California Office of Planning and Research of
potential and confirmed hazardous waste and substance sites throughout California. The
Cortese list includes tank leaks compiled by the State Water Resources Control Board
(SWRCB), abandoned hazardous waste sites by the DTSC, California Bond Expenditure Plan
(BEP) and solid waste disposal sites with known migration of hazardous waste. A total of 13
properties within a one half-mile radius of the project were identified on the Cortese list. These
properties are described in the Phase 1 (Padre 2010).
4.5.2.3 Local Policies and Regulations
San Luis Obispo County Air Pollution Control District
The federal and state Clean Air Acts are enforced locally by the San Luis Obispo County Air
Pollution Control District (SLOAPCD). The SLOAPCD regulates potential discharges of criteria
air pollutants (including organic compounds that contribute to ozone formation) and toxic air
contaminants.
San Luis Obispo County Health Agency
Pursuant to State law and local ordinance, the Division of Environmental Health of the San Luis
Obispo County Health Agency conducts inspections to ensure proper handling, storage, and
disposal of hazardous materials and proper remediation of contaminated sites. In addition, the
Hazardous Materials Release Response Plans and Inventory Law of 1985 (Business Plan Act,
[i.e., Chapter 6.95 of Division 20 of the California Health and Safety Code]) requires that any
business that handles or stores hazardous materials prepare a Hazardous Materials Business
Plan. Under this law, businesses are required to submit inventories of on-site hazardous
materials and wastes and the locations where these materials are stored and handled. This
information is collected and certified by San Luis Obispo County Environmental Health
Department for emergency response purposes. There are no cities within San Luis Obispo
County that have adopted and implemented their own hazardous materials programs in lieu of
the County program; however, the City of San Luis Obispo Fire Department is a participating
agency with San Luis Obispo County.
4.5.3 Significance Criteria
Appendix G of the CEQA Guidelines states that a project would normally have a significant
impact if it would create a potential health hazard or involve use, production, or disposal of
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materials that pose a hazard to people, animal, or plant populations in the area affected. For the
purposes of this analysis, the questions to be asked include:
1. Create a significant hazard to the public or the environment through the routine
transport, use, or disposal of hazardous materials;
2. Create a significant hazard to the public or the environment through reasonably
foreseeable upset and accident conditions involving the release of hazardous materials
into the environment;
3. Emit hazardous emissions or handle hazardous or acutely hazardous materials,
substances, or waste within one-quarter mile of an existing or proposed school;
4. Be located on a site which is included on a list of hazardous materials sites compiled
pursuant to Government Code Section 65962.5 and, as a result, would it create a
significant hazard to the public or the environment;
5. For a project 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, would the project result
in a safety hazard for people residing or working in the project area;
6. For a project within the vicinity of a private airstrip, would the project result in a safety
hazard for people residing or working in the project area;
7. Impair implementation of or physically interfere with an adopted emergency response
plan or emergency evacuation plan; or
8. Expose people or structures to a significant risk of loss, injury or death involving wildland
fires, including where wildlands are adjacent to urbanized areas or where residences are
intermixed with wildlands.
As identified in the Initial Study (refer to Appendix A), questions 3 through 8 are not applicable
to the proposed project. The project also does not propose routine transport, use, or disposal of
hazardous materials, and therefore question 1 is not relevant to the following discussion.
4.5.4 Impacts and Mitigation Measures
The following includes a discussion of the relevant significance criteria from Appendix G.
4.5.4.1 Create a significant hazard to the public or the environment through reasonably
foreseeable upset and accident conditions involving the release of hazardous
materials into the environment
Based on the site assessment reports prepared for the project, excavation proposed in the Flow
Return area and at the “Madonna Bench”, which is downstream and on the west side of the
channel, will encounter soils/material that should be treated as a hazardous material.
Constituents in these materials may include elevated levels of lead and petroleum-based
products. It can be assumed that at least approximately 410 cubic yards of material
(approximately 40 truckloads) will need to be hauled to an appropriate disposal facility. During
excavation construction personnel could be exposed to the hazardous materials, or loose soil
could potentially erode or be deposited in the creek channel. In addition, if trucks do not properly
secure the hazardous material, the transport of the soil could potentially expose residents to
hazardous materials during the hauling process.
Given the long history of commercial use in the area, despite the substantial testing that has
occurred, there remains a potential for as yet undiscovered contaminated soil to be encountered
during construction.
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HAZ Impact 1 During excavation of the project components construction personnel and the
local environment may be exposed to hazardous materials that exist in the soils.
Haz-mm-1 Prior to initiation of construction, the District shall submit to the City of San Luis
Obispo Fire Department a Construction Materials Management Plan (CMMP).
The CMMP plan shall be implemented throughout construction. The CMMP shall
at minimum present an overview of the procedures and protocols that will be
utilized during the project to safely and appropriately recover, handle,
characterize, store, transport, and dispose of any contaminated materials
encountered during construction of the project. In the event that hazardous
materials are encountered during excavation activities, the contaminated soil
shall be excavated to the extent necessary to safely construct the project.
Residual Impact. Haz-mm-1 would require that the District prepare a CMMP that would address
the handling of known and potentially encountered hazardous materials. The CMMP would
describe how contaminated materials should be separated from the other materials, what kind
of containment would be required (i.e. tarping, barrels, etc.) and what human safety measures,
such as dust control and handling procedures should be implemented to minimize exposure.
The CMMP would be reviewed by the two local agencies with the responsibility for regulating
hazardous materials. This measure would reduce potential impacts to a less than significant
level. No additional measures are required.
4.5.5 Cumulative Impacts
Potential hazards in this EIR are location-specific to the extent that they may result in significant
impacts on the localized environment, but they are not “cumulative” in the sense normally
applied in CEQA documents. Further, the impacts identified in this section are associated with
relatively short-term construction activities and the ongoing clean-up of contamination and
decommissioning of the Marine Terminal will reduce potential exposure to hazards during
construction. The mitigation measures that have been identified for the proposed project would
apply cumulatively as well. Cumulative impacts would be less than significant. No additional
mitigation is required.
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4.6 Hydrology / Water Quality
This section includes a discussion of local flooding and drainage conditions, and factors
affecting water quality such as erosion and sedimentation. The section draws from previous
analysis of the watershed, including the EIR/EIS and the Project Report Design Review
(Wallace Group, 2014).
4.6.1 Existing Conditions
The overall hydrologic conditions of the San Luis Obispo Creek watershed are described in
detail in the EIR/EIS and Waterway Management Plan (WMP). The project is located entirely
within an area identified as Reach 10. The northern portion of the project corridor is
approximately 500 feet downstream of the confluence of Stenner and San Luis Obispo creeks.
Reach 10 is described in the WMP as follows:
“Reach 10 is a 1.2-km stretch extending from the Madonna Road Bridge upstream to the
confluence with Stenner Creek. This reach was also surveyed in 1997 as part of the Phase I
studies. For 125 meters upstream of the Madonna Road Bridge the steep west bank is being
undercut at the toe, potentially threatening the Highway 101 roadway base fill. Moving
upstream, the outside of the next meander bend is protected by a mixture of rip-rap, gabions
and grouted rock. Upstream of this is a 100-meter stretch of relatively undisturbed channel
before the creek bends back to the east. The outside of this bend, which is protected by sacrete,
runs closely alongside Highway 101. The west bank on the upstream edge of the sacrete is
over-steepened and could result in gradual failure of the sacrete.
The Hayward Lumber yard, which was repaired in 1999 as part of the Phase I program is 180
meters upstream of the sacrete wall. Approximately 50 meters upstream of the Hayward
Lumber is the Bianchi Lane Bridge. On the west bank directly upstream of this bridge, there are
a series of culverts that empty into the creek from the top of the bank. The flows from these
culverts are creating gullies, which will continue to widen and may eventually jeopardize the
bridge foundation. Between the Bianchi Bridge and the Marsh Street Bridge upstream, the
channel is straight with steep moderately vegetated banks. Portions of the west bank in this
200-meter stretch show signs of incipient erosion. Between the Marsh Street Bridge and the
confluence with Stenner Creek, SLO Creek passes under another small bridge and through a
straight stretch of well-vegetated trapezoidal channel. Channel gradient steepens in this area.”
4.6.1.1 Local Flooding and Drainage
San Luis Obispo Creek, between Marsh Street and Madonna Road, has flooded six times in the
last 40-50 years (Questa 2009). The flooding occurs for a number of reasons, including the
creek cross-section is narrow in this area, the floodplain is heavily developed on the eastern
side of the creek and the Marsh Street Bridge and the Bianchi Lane Bridge can act as
constriction points. During flood events the water level in the creek, immediately north of the
Marsh Street Bridge, rises above the top of the creek bank during periods of heavy rain. The
creek water subsequently flows into the adjacent streets, damaging public and private property.
The Mid-Higuera area of San Luis Obispo creek has a large upstream watershed, including the
Stenner Creek and Brizzolara Creek tributaries. A comprehensive watershed model for San Luis
Obispo Creek was developed as part of the WMP. The peak flows derived through the WMP
model are the basis for analysis of the Mid-Higuera project. Peak flows for this section of San
Luis Obispo Creek are summarized in Table HWQ-1.
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Table HWQ-1. San Luis Obispo Creek Peak Flows
Return Interval (year) Runoff Rate (cfs)
10 7,769
25 9,676
100 12,501
Per the WMP, flow in the creek can respond very quickly to short high intensity rainfall bursts,
and floods in the creek tend to be of high magnitude but relatively short duration. Figure HWQ-1
shows the 100-year flood plain in the project area. The floodplain includes nearly the entire
project area and surrounding neighborhoods.
4.6.1.2 Water Quality
The issue of surface water quality is important because of the value of the creek for several
endangered or threatened plant and animal species. The Regional Water Quality Control Board
(RWQCB) has identified multiple beneficial uses for the creek, including present and potential
beneficial uses for municipal supply, agricultural supply, groundwater recharge, recreation,
wildlife habitat, warm and cold fresh water habitat, migration of aquatic organisms, spawning,
reproduction and/or early development of fish, and commercial and sport fishing (City of San
Luis Obispo 2014).
Surface water entering watercourses from undeveloped areas usually travels over vegetative
cover, and erosion and sedimentation is a slow, gradual process. Urbanized areas typically
contain pollutants on the ground surface that are harmful to water quality. These include heavy
metals, hydrocarbons, detergents, fertilizers, and pesticides that originate from vehicle use and
commercial and residential land use activities. For the most part, these pollutants are
associated with sediments that collect on roadways and are flushed into the creek system
during construction or by rainfall. Construction activities can also create erosion and cause
sediment to be transported off-site by surface water runoff. Therefore, water quality depends
mainly on the hydrologic characteristics of the drainage basin, the makeup of the soils in the
watershed, and sources of pollution in the watershed.
The RWQCB has indicated that water quality in the creek is generally good, however, nitrogen
and pathogen levels periodically exceed the Total Maximum Daily Limits (TMDL) established
(RWQCB 2013). The largest contributor to the nitrate issues are agricultural operations
upstream and downstream of the City limits and the City’s Water Recycling Facility. Water
quality monitoring is conducted regularly throughout the watershed, with the nearest location on
Stenner Creek upstream of the project area in downtown San Luis Obispo.
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4.6.1.3 Regulatory Setting
4.6.1.3.1 Federal Regulations
The Clean Water Act
The Clean Water Act (CWA) of 1972 establishes the basic structure for regulating discharges of
pollutants into the waters of the United States and regulates quality standards for surface
waters. Under the CWA, the EPA has implemented many pollution control standards for the
industry along with water quality standards for all contaminants in surface waters. The CWA
made it unlawful to discharge any pollutant from a point source into navigable waters, unless the
EPA authorized a National Pollutant Discharge Elimination System (NPDES) permit.
Federal Emergency Management Agency Flood Zones
The Federal Emergency Management Agency (FEMA) has delineated both special hazard flood
areas and risk premium flood zones applicable to individual communities. The Flood Insurance
Rate Maps help private citizens and insurance companies locate properties in flood risk areas,
aid lending institutions when making loans, and administer floodplain management regulations
in order to mitigate flood damage. The majority of the project site is located within the 100-year
floodplain, and has at least a 1% annual chance floodplain. The proposed project may alter the
existing FEMA flood limit delineations within the project area.
4.6.1.3.2 State Regulations
Under Section 401 of the Clean Water Act, applicants for a federal license or permit such as a
Section 404 Permit must obtain certification from the state (RWQCB), or a waiver of
certification, that the activity would not adversely affect water quality.
In 2013 the Central Coast Region RWQCB adopted Resolution Number R3-2013-0032
regarding Post-Construction Stormwater Management Requirements intended to focus on
discharges that threaten beneficial uses and to require implementation of Best Management
Practices to reduce stormwater pollutant discharges to the maximum extent practicable and
protect water quality and beneficial uses.
4.6.1.3.3 City of San Luis Obispo Regulations
City of San Luis Obispo Engineering Standards. Per the City’s recently prepared Land Use and
Circulation Element Programmatic Environmental Impact Report, current Engineering Standards
for the City include the following requirements:
x All new development or redevelopment shall comply with the criteria and standards set
forth in the Waterways Management Plan – Drainage Design Manual, applicable area
specific plans, and the Post-Construction Stormwater Management Requirements for
Development Projects in the Central Coast Region, adopted by the Central Coast
Regional Water Quality Control Board. Where requirements conflict, the stricter shall
apply.
x Stormwater Control Plan, and Operation and Maintenance Plan are required prior to final
approvals.
x Projects with pollution generating activities and sources must be designed to implement
operation or source control measures consistent with recommendations from the
California Stormwater Quality Association Handbook for New Development and
Redevelopment or equivalent, including: a) Accidental spills or leaks, b) Interior floor
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drains, c) Parking / storage areas and maintenance, d) Indoor and structural pest
control, e) Landscape / outdoor pesticide use, f) Pools, spas, ponds, decorative
fountains and other water features, g) Restaurants, grocery stores, and other food
service operations, h) Refuse areas, i) Industrial processes, j) Outdoor storage of
equipment or materials, k) Vehicle and equipment cleaning, repair, and maintenance, l)
Fuel dispensing areas, m) Loading docks, n) Fire sprinkler test water, o) Drain or wash
water from boiler drain lines, condensate drain lines, rooftop equipment, drainage
sumps, and other sources, p) Unauthorized non-stormwater discharges, and q) Building
and grounds maintenance
x Design should prevent water from contacting work areas, prevent pollutants from coming
in contact with surfaces used by stormwater runoff, or where contact is unavoidable, and
treat stormwater to remove pollutants.
x Operations and maintenance activities required to achieve Source Control are to be
included in the Operation and Maintenance Plan submitted for approvals and recorded
with the property as required by ordinance.
4.6.1.3.4 Waterway Management Program
The WMP, which was developed in 2003 and includes the Stream Maintenance and
Management Program (SMMP) and the Drainage Design Manual (DDM) are used by the City
and County of San Luis Obispo (collectively “Zone 9”) to design flood control, water quality, and
habitat enhancement projects within the San Luis Obispo Creek watershed. These documents
outline both policies and specific measures that guide the design, operation and maintenance of
these improvements. Specifically, recommended bypass channel design is described and
shown in Section 5.3.2 and in Figure 5-4 of the DDM. The proposed project is consistent with
those descriptions and others related to treatment of exotic species and enhancement of
aquatic resources habitat by installing large root wads, for example.
4.6.2 Significance Criteria
Criteria for evaluating the significance of hydrology and water quality impacts included in the
CEQA Guidelines, Appendix G, are directed toward identifying substantial changes in drainage
patterns, drainage volumes, or violations of water quality standards. Impacts would be
considered significant if the proposed project would result in any of the following:
1. Potentially degrade surface or groundwater quality below standards established by the
Regional Water Quality Control Board;
2. Substantially interfere with groundwater recharge;
3. Substantially alter the existing drainage pattern of the area such that substantial erosion
or sedimentation occurs;
4. Substantially alter the existing drainage pattern or substantially increase the rate or
amount of surface runoff in a manner which results in flooding;
5. Create or contribute runoff which would exceed the capacity of stormwater drainage
systems; or
6. Substantially add additional sources of polluted runoff to a water body.
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4.6.3 Impacts and Mitigation Measures
The proposed project will involve the operation of heavy machinery within and adjacent to the
creek channel, require dewatering in multiple locations throughout the project area, and require
substantial grubbing and other vegetation removal. These activities could introduce pollutants
such as petroleum products into surface or groundwater directly or indirectly, and expose soils
to erosion, impacting water quality. Due to the nature of the project, it is not expected to (1)
degrade surface water quality below RWQCB standards; (2) affect groundwater recharge; (3)
increase the amount of rate of surface runoff, or (4) contribute runoff that would exceed the
capacity of stormwater drainage systems; therefore, these criteria are not discussed further.
There is potential for the project to alter drainage patterns, and/or substantially add pollutants to
San Luis Obispo Creek. These potential impacts are described below.
4.6.3.1 Substantially alter the existing drainage pattern of the area such that substantial
erosion or sedimentation occurs.
Development adjacent to or near surface waters is subject to specific design and construction
conditions in order to ensure the project’s stormwater is adequately contained and directed
without adversely affecting downstream locations. Typically, an impact would occur if the
proposed project directed construction runoff or stormwater to areas where downstream
capacity could be exceeded. Because the proposed project would increase stormwater capacity
of the creek, the assessment focuses instead on impacts to water quality which could result
from the use of heavy machinery in and near the creek, grading, vegetation removal, and the
construction of new structures.
Construction activities would significantly impact water quality due to the exposure of large
areas of soil to erosive forces, the need to dewater during construction, and due to the presence
of fuel, oil, and other pollutants on site for construction purposes. Because of the work proposed
within the channel of the creek and the size of the area of disturbance, implementation of the
project will be contingent upon the receipt of permits from the United States Army Corps of
Engineers, Regional Water Quality Control Board, and the California Department of Fish and
Wildlife. Prior to the issuance of those permits, the regulatory agencies will require a number of
project-specific plans to address potential water quality/hydrology impacts. These plans are
described in Chapter 2.0 Project Description and include, but are not limited to: Diversion and
Dewatering Plan, Stormwater Pollution Prevention Plan (SWPPP), Sedimentation and Erosion
Control Plan (ESCP), Spill Prevention Control and Contingency Plan (SPCC), and a Habitat
Mitigation and Monitoring Plan (HMMP). In addition a Caltrans encroachment permit is required,
and Caltrans will have an opportunity to confirm the proposed erosion control plan is adequate
to protect Highway 101.
Implementation of these plans, along with the WMP measures, which are applied to all projects
within the City limits, would reduce impacts to a less than significant level. No additional
mitigation measures are required.
4.6.3.2 Substantially add additional sources of polluted runoff to a water body.
Under existing conditions, during flooding events flood waters will overtop the creek channel
upstream of the Marsh Street Bridge and flow “down” South Higuera Street, eventually re-
entering the channel between Marsh Street and Madonna Road through the storm drains or as
sheet flow through properties between South Higuera Street and the creek. The flood waters
carry debris from upstream as well as pollutants from the surface streets they run across (e.g.
Marsh Street, South Higuera Street, Pacific Street).
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The proposed Flow Return would be constructed to provide a specific point where flood waters
could return to the creek channel, potentially reducing flooding further to the south. Under
existing conditions, flood waters already cross the property and re-enter San Luis Obispo Creek;
however, the Flow Return would potentially concentrate these flows and the associated
pollutants.
HWQ-Impact 1 The Flow Return would potentially concentrate polluted flood water and
discharge it to the creek system with no treatment.
HWQ-mm-1 Prior to construction, to minimize the potential for concentrating pollutants at the
Flow Return where flood waters would re-enter San Luis Obispo Creek, this
component shall be designed to maximize the potential for passive stormwater
treatment.
Residual Impact. Implementation of measure HWQ-mm-1 would reduce potential impacts to
less than significant. No additional measures are required. Given that there is currently no
treatment of these flood waters and the flooding problems along Mid-Higuera, the Flow Return,
along HWQ-mm-1, would potentially have a beneficial impact to flooding and water quality.
Based on preliminary analysis, this mitigation measure would not increase impacts to
jurisdictional areas, biological resources, or cultural resources.
4.6.4 Cumulative Impacts
Typical flooding, hydrology, and water quality impacts resulting from development are related to
an increase in impervious surfaces, increased discharge of stormwater or sediment into a
drainage system, or development within a floodplain which may reduce the floodplain capacity
and affect upstream or downstream land uses. These impacts may contribute cumulatively
along with other projects to result in significant impacts. However, the proposed project is a
construction project designed to increase flood control capacity. No impervious surfaces are
proposed.
Projects that potentially have a direct effect on San Luis Obispo Creek are generally highly
regulated. The projects described above would all require permits from resource agencies
including the CDFW, USACE, and the RWQCB. These agencies ensure that impacts to water
quality and habitat are limited. The proposed project is also subject to regulations by all of these
agencies and therefore would not contribute cumulative impacts to water quality or alterations of
the local hydrologic conditions. Cumulative impacts to Hydrology and Water Quality are less
than significant. No mitigation beyond that already discussed in this EIR is required.
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4.7 Noise
This section describes the existing environment, the potential noise impacts from construction of
the proposed project, and necessary mitigation measures. As described in the initial study in
Appendix A, the project would not generate noise after construction (i.e. operational noise). This
section is based primarily on the Noise Impact Assessment for the Proposed Mid-Higuera
Bypass Project (Ambient, 2016). A copy of that report is available for review at the District.
4.7.1 Existing Conditions
The human response to environmental noise is subjective and varies considerably from
individual to individual. Noise in the community has often been cited as a health problem, not in
terms of actual physiological damage, such as hearing impairment, but in terms of inhibiting
general well-being and contributing to undue stress and annoyance. The health effects of noise
in the community arise from interference with human activities, including sleep, speech,
recreation, and tasks that demand concentration or coordination. Hearing loss can occur at the
highest noise intensity levels. When community noise interferes with human activities or
contributes to stress, public annoyance with the noise source increases. The acceptability of
noise and the threat to public well-being are the basis for land use planning policies preventing
exposure to excessive community noise levels.
Noise-sensitive land uses are generally considered to include those uses where noise exposure
could result in health-related risks to individuals, as well as places where quiet is an essential
element of their intended purpose. Residential dwellings are of primary concern because of the
potential for increased and prolonged exposure of individuals to both interior and exterior noise
levels. Additional land uses such as parks, historic sites, cemeteries, and recreation areas are
also considered sensitive to increases in exterior noise levels. Schools, churches, hotels,
libraries, and other places where low interior noise levels are essential are also considered
noise-sensitive land uses.
The project site is located within and adjacent to San Luis Obispo Creek between the Marsh
Street Bridge and Madonna Road Bridge. The proposed construction area is bordered on the
west by Highway 101 and on the east by Higuera Street and existing development. The
topography in the area is generally flat, with little topographic variation, with the exception of a
small knoll between Highway 101 and the northern half of the South Street Bypass.
The adjacent existing development consists largely of a mix of light industrial, commercial, and
residential land uses. The nearest noise-sensitive land uses include residential dwellings, the
nearest of which are located adjacent to and east of San Luis Obispo Creek along Brook Street,
south of South Street. St. Luke Missionary Baptist Church and Eto Park are also located along
Brook Street, south of South Street. In addition, Mathews Trailer Lodge is located adjacent to
and east of San Luis Obispo Creek, south of Bianchi Lane. These areas are shown on Figure
NS-1.
4.7.2 Regulatory Setting
4.7.2.1 City of San Luis Obispo General Plan
The existing General Plan Noise Element establishes operational standards for siting of new
land uses; however, it contains no policies or programs that address the identification and
mitigation of temporary construction noise generated by land development projects on existing
sensitive receptors.
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4.7.2.2 City of San Luis Obispo Municipal Code
The City’s Noise Control Ordinance, contained in Municipal Code, Chapter 9.12. Section
9.12.050, limits construction and demolition activities that would result in a noise disturbance to
nearby land uses to between the hours of 7:00 a.m. and 7:00 p.m., Monday through Saturday.
Noise-generating construction and demolition activities are prohibited on Sundays and holidays.
The ordinance further states that, where technically and economically feasible, construction
activities shall not exceed specified standards. For areas consisting of mixed residential and
commercial uses, maximum construction-generated noise levels should be limited to 85 dBA
during the daytime hours (7:00 a.m. to 7:00 p.m.) During the nighttime hours, maximum
construction-generated noise levels should be limited to 70 dBA. The City’s noise ordinance
also establishes noise standards for long-term noise exposure.
dBA is an overall frequency-weighted sound level in decibels that approximates the frequency
response of the human ear. For perspective, a gas lawn mower produces approximately 95 dBA
when the user is 3 feet away. Ambient noise levels in commercial areas are approximately 65
dBA, and in rural areas in the evening the dBA could be expected to be approximately 25 dBA.
4.7.3 Significance Criteria
Criteria for evaluating the significance of potential noise impacts are included in the CEQA
Guidelines, Appendix G. Impacts would be considered significant if the proposed project would
result in any of the following:
1. Exposure of persons to or generation of noise levels in excess of standards established
in the local general plan or noise ordinance, or applicable standards of other agencies;
2. Exposure of persons to or generation of excessive groundborne vibration or
groundborne noise levels;
3. A substantial permanent increase in ambient noise levels in the project vicinity above
levels existing without the project;
4. A substantial temporary or periodic increase in ambient noise levels in the project vicinity
above levels existing without the project;
5. For a project 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, would the project
expose people residing or working in the project area to excessive noise levels; or
6. For a project within the vicinity of a private airstrip, would the project expose people
residing or working in the project area to excessive noise levels.
Ground-borne vibration levels would be considered to have a potentially significant impact if
resultant vibration levels at the nearest structures would exceed 0.3 in/sec ppv (peak particle
velocity) for structural damage and 0.2 in/sec ppv for annoyance to building occupants, based
on Caltrans-recommended thresholds.
The proposed project would not result in increased exposure of sensitive land uses to aircraft
noise, nor would the proposed project interfere with airport operations. As a result, evaluation of
long-term exposure to aircraft noise is not discussed further in this report.
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4.7.4 Impacts and Mitigation Measures
4.7.4.1 Exposure of persons to or generation of noise levels in excess of standards
established in the local general plan or noise ordinance, or applicable standards
of other agencies
The existing General Plan Noise Element establishes operational standards for siting of new
land uses; however, it contains no policies or programs that address the identification and
mitigation of temporary construction noise generated by land development projects on existing
sensitive receptors. Implementation of the proposed project would not result in the creation of
new land uses, nor would the project result in the installation of new transportation or non-
transportation noise sources. As a result, the proposed project would not conflict with noise
standards established in the City’s General Plan. This impact would be less than significant.
4.7.4.2 A substantial permanent increase in ambient noise levels in the project vicinity
above levels existing without the project
The proposed project would not result in the installation of any stationary equipment or long-
term operational activities that would generate noise. In addition, for those existing land uses
located nearest Highway 101, the excavation of the new channels and construction of terraces
and benches would not result in changes to the existing topography that would affect existing
noise shielding characteristics of the site. Furthermore, although the proposed project would
result in the removal of some existing vegetation, significant changes in traffic noise exposure at
land uses located nearest Highway 101 would not occur. This impact is considered less than
significant.
4.7.4.3 A substantial temporary or periodic increase in ambient noise levels in the project
vicinity above levels existing without the project?
Construction noise typically occurs intermittently and varies depending upon the nature or
phase of construction (e.g., land clearing, grading, excavation, and paving). Noise generated by
construction equipment, including earth movers, material handlers, and portable generators, can
reach high levels. Although noise ranges are generally similar for all construction phases, the
initial site preparation phase tends to involve the most heavy-duty equipment having a higher
noise-generation potential. Noise levels associated with individual construction equipment likely
required for construction of the proposed project were provided in Table NS-1.
In accordance with the City’s noise control ordinance, construction-generated noise levels would
be considered significant if maximum noise levels would exceed 85 dBA during the daytime
hours (e.g., 7:00 a.m. to 7:00 p.m.) or 60 dBA during the nighttime hours (e.g., 7:00 p.m. to 7:00
a.m.) Construction activities that would result in significant increases in potential sleep
disturbance or activity interference at nearby noise-sensitive land uses would also be
considered to have a potentially significant impact.
Noise levels generated by some of the loudest construction equipment likely to be active on the
proposed project are shown in Table NS-1.
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Table NS-1
Typical Construction Equipment Noise Levels
Equipment dBA at 50 feet
Air Compressor 78
Backhoe 78
Dozer 82
Forklift 85
Grader 85
Truck 77
Based on the noise levels identified in Table NS-1, intermittent noise levels at noise-sensitive
land uses located within approximately 50 feet of the construction site would be approximately
85 dBA or less. Depending on the activities conducted and equipment used, average-hourly
noise levels at these nearest uses would range from approximately 73 dBA to 82 dBA 50 feet.
Haul trucks required for the delivery of construction materials would also result in short-term
detectable increases in traffic noise levels along nearby roadways.
Construction-generated noise levels associated with construction of the proposed project
components would not be anticipated to exceed the City’s instantaneous daytime noise
standard of 85 dBA. However, in the event that construction activities were to occur during the
nighttime hours, resultant noise levels at the property line of the nearest residences would
exceed the City’s noise standards of 60 dBA Lmax. In addition, construction activities occurring
during the more noise-sensitive nighttime hours could result in increased levels of annoyance
and potential sleep disruption to occupants of nearby residential dwelling units. Furthermore,
construction activities occurring in the vicinity of St. Luke Missionary Baptist Church could
interfere with onsite services. Onsite services typically occur on Sundays, as well as, on
Monday and Wednesday nights (Ambient 2016).
NS-Impact 1 Night-time or weekend construction would potentially significantly impact
sensitive receptors in the project area.
NS-mm 1 To reduce potential noise impacts, the following measures shall be implemented
during construction:
x Noise-generating construction activities shall be limited to between the hours of 7:00
a.m. and 7:00 p.m., Monday through Saturday.
x Noise-generating construction activities shall be prohibited on Sundays and holidays.
x Construction equipment shall be properly maintained and equipped with noise-
reduction intake and exhaust mufflers and engine shrouds, in accordance with
manufacturers’ recommendations.
x Equipment engine shrouds shall be closed during equipment operation.
x Lay-down yards and semi-stationary equipment such as pumps or generators shall
be located at the furthest practical distance from noise-sensitive land uses.
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Residual Impact. Implementation of this measure would reduce short-term noise impacts to a
less than significant level. No additional measures are required.
4.7.5 Cumulative Impacts
Because the project would not produce any operational; noise, potential cumulative impacts are
solely limited to short-term construction noise levels. There are no additional major construction
projects included in the cumulative development scenario. Therefore, the project would not
contribute to any cumulative noise impacts. Potential cumulative impacts are less than
significant. No additional measures are required.
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5 Other CEQA Sections
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5.0 Other CEQA-mandated Sections
Section 15126 of the California Environmental Quality Act (CEQA) Guidelines requires
Environmental Impact Reports to include the following topics:
1. significant environmental effects of the proposed project;
2. significant environmental effects which cannot be avoided if the proposed project is
implemented;
3. significant irreversible environmental changes which would be involved in the proposed
project should it be implemented;
4. growth-inducing impact of the proposed project;
5. the mitigation measures proposed to minimize the significant effects; and
6. alternatives to the proposed project.
In addition, CEQA Guidelines requires Lead Agencies to consider the energy impacts of
proposed projects, with an emphasis on avoiding or reducing inefficient, wasteful and
unnecessary consumption of energy. Appendix F of the CEQA Guidelines suggests that
conserving energy would include (1) decreasing overall per capita energy consumption; (2)
decreasing reliance on natural gas and oil; and (3) increasing reliance on renewable energy
sources. This chapter of the EIR considers these “other topics”.
5.1 Section 15126 Topics
Topics 1, 2, and 5 are included in Chapter 4 of this EIR. Topics 3 and 4 are considered below.
Topic 6 is considered in Chapter 6.
5.1.1 Significant Irreversible Environmental Changes Which Would Be Involved in the
Proposed Project Should It Be Implemented
Section 15126.2(c) of the CEQA Guidelines states that use of nonrenewable resources during
the initial and continued phases of a proposed project may be irreversible if a large commitment
of these resources makes their removal, indirect removal, or non-use thereafter unlikely. Non-
renewable resources, such as natural gas, petroleum products, asphalt, petrochemical
construction materials, steel, copper and other metals, and sand and gravel are considered to
be commodities which are available in a finite supply. The processes that created these
resources occur over a long period of time. Therefore, the replacement of these resources
wouldn’t occur over the life of the project. To varying degrees, the aforementioned materials are
all readily available and some materials, such as asphalt, sand and gravel, are abundant. Other
commodities, such as metals, natural gas, and petroleum products, are also readily available,
but they are finite in supply given the length of time required by the natural process to create
them. The demand for all such resources is expected to increase regardless of whether or not
the project is developed. Increases in population will directly result in the need for resources.
Resources necessary for implementation of the proposed project include gravel and rock for the
bypass channel transition areas. The majority of the resources would be used during short-term
project construction. The long-term commitment of resources associated with maintenance of
the project is limited.
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5.1.2 Growth-Inducing Impacts
CEQA Guidelines Section 15126.2 (d) state that in the preparation of an EIR, growth inducing
impacts that need to be addressed are ones that “…foster economic or population growth, or
the construction of additional housing…remove obstacles to population growth…encourage and
facilitate other activities that could significantly affect the environment either individually or
cumulatively”. An example given is the expansion of a wastewater treatment plant allowing for
increased construction in service areas. Based on this direction the proposed project was
evaluated in order to determine if any part of the project demonstrates the potential for growth
inducing impacts. Development in the area is currently constrained by the flood potential,
required creek setbacks, existing development which includes a mobile home park and a large
lumber/hardware supply yard.
The project would reduce the recurrence interval for flooding along the section of Higuera Street
between Marsh Street and Madonna Road. This improvement could potentially be considered
as reducing an obstacle to growth as it would make it more attractive to intensify development
along the Higuera Street corridor. However, potential growth-inducing impacts are less than
significant because:
1. the majority of the parcels adjacent to the project corridor are already developed;
2. each parcel would still be located within the 100-year flood plain even with
implementation of the project;
3. development proposed in the future would be subject to City-mandated creek setbacks
which didn’t exist when the parcels were first developed; and
4. the only relatively large and vacant parcels within the project corridor will be used for the
bypass channels and the Flow Return, and therefore would not be developed.
5.2 Appendix F: Energy Conservation
The energy used for the project is primarily related to the initial construction activities.
Construction vehicles would use non-renewable resources such as diesel fuel and other
petroleum products during construction. Once the project is constructed, “operation” of the
project would be limited to periodic (i.e. every 5-10 years, possibly) sediment management in
the bypass channels. This would involve periodically removing sediment from the channels in
the event that it did accumulate.
There are currently no feasible alternatives to the use of heavy diesel-powered equipment for
the construction activities. The project will be required to comply with the mitigation measures in
the Air Quality/Greenhouse Gas section of this SEIR. Those measures encourage fuel
conservation as a method of reducing emissions. Further, due to its location within urban San
Luis Obispo, it is expected that the length of the trips made by construction personnel, the
heavy equipment, and trucks hauling spoils offsite would be relatively short when compared to
projects which occur in more rural areas. Because the operation of the project is limited, there
are no feasible energy conservation measures to be implemented.
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6.0 Alternatives Analysis
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6.0 Alternatives Analysis
6.1 Introduction
Section 15126.6 (a) of CEQA, requires an EIR to:
“describe a reasonable range of alternatives to a project, or to the location of a project, which
could feasibly attain most of the basic objectives of the project but would avoid or substantially
lessen any of the significant effects of the project, and evaluate the comparative merits of the
alternatives.”
The primary objectives of the project are to increase the flood-carrying capacity (up to a 25-year
storm in some locations) of San Luis Obispo Creek from Marsh Street to Madonna Road, while
enhancing and protecting water quality as well as special-status species habitat within the
project area.
Significant effects of the project are primarily construction-related and short-term. No significant
and unavoidable (Class I) impacts were identified. This chapter includes a qualitative
assessment of various alternatives, which are summarized in Table 6.1.
6.2 Alternative Evaluation
The EIR/EIS prepared for the WMP includes a robust discussion of watershed-wide alternatives
to the program components included in the WMP, and specific alternatives to the Mid-Higuera
Bypass project. Alternatives that were considered but determined to be infeasible by the Zone 9
Advisory Committee during the WMP process included:
1. Buried Bypass Culvert – This alternative includes constructing a buried bypass culvert
around downtown that would run under Pacific Street or down Meadow Creek.
2. Floodwalls – Includes the construction of floodwalls along the east bank of San Luis
Obispo Creek from approximately Nipomo Street to Madonna Road
3. Significant Channel Enlargement – Involves significantly widening the channel of SLO
Creek between Marsh and Madonna Road to provide 50-year flood capacity.
4. Flood Detention Basins – Requires construction of flood detention basins in upper
Stenner Creek, and upper San Luis Obispo Creek above Reservoir Canyon Road
The EIR/EIS concluded that stream management and maintenance was a key component for
management of the watershed and therefore that component was removed from consideration.
For more information on these and all of the alternatives previously considered, refer to the
WMP EIR/EIS.
Despite the fact that the EIR/EIS considered a reasonable range of alternatives to the Mid-
Higuera Bypass project specifically, the SEIR includes an additional discussion of alternatives in
an attempt to reduce the severity of the short-term construction-related impacts identified.
These alternatives include:
1. Land Purchase/Business Relocation - Purchasing the properties along Higuera Street
most vulnerable to flooding, thereby reducing the flood risk;
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2. Marsh Street Bridge Replacement - Reconstructing the Marsh Street Bridge and
Highway 101 interchange;
3. No Project Alternative – This alternative is required by CEQA, and in this case would
include periodic maintenance of the creek reach, including the vegetation and sediment
management that is already periodically performed by the County; and
4. Phased Project – Phasing construction over multiple years to reduce short-term
construction-related impacts to noise, air quality and traffic, as well as to minimize
disturbance to biological resources within the creek channel in any single year.
6.3 Land Purchase/Business Relocation
This alternative would mitigate the flooding impacts by reducing the number of structures,
businesses, and residents that could be exposed to flooding. The City would purchase the
properties and demolish structures, recreating a “floodplain” adjacent to Higuera Street. This
alternative is likely economically infeasible due to the exorbitant costs related to purchasing the
properties in question. Further, it would reduce the area available for commercial use in the City
of San Luis Obispo, potentially increasing the demand for greenfield commercial development
on the edges of town. For that reason, this alternative is inconsistent with the City’s General
Plan policies. Due to its financial infeasibility and inconsistencies with the General Plan and Mid-
Higuera Enhancement Plan, this alternative is not considered further.
6.4 Marsh Street Bridge Replacement
The Marsh Street Bridge over San Luis Creek includes the intersection of Marsh Street with the
Highway 101 onramp and off-ramp. The bridge has been identified as a major constriction for
San Luis Obispo Creek, and its current design allows for the development of large sandbars at
its upstream end. Due to the street configuration in this area, this alternative would likely involve
the reconstruction of the on and off-ramps, as well as adjacent portions of Marsh Street and
Higuera Street. In addition to construction costs this alternative would require the purchase of
private property adjacent to the roads. Further, the level of review and coordination with
Caltrans would require engineering and environmental studies that could take 10 years or more
to accomplish given that the project isn’t “programmed” into any current trans portation planning
documents. Due to these issues, it can be reasonably determined that this alternative is
speculative and infeasible.
6.5 No Project Alternative
The No Project Alternative would include the City performing periodic maintenance of the
vegetation and sediment that accumulates within the channel – particularly that which collects
within the Marsh Street bridge barrels. Depending on the extent of the maintenance activities
and the hydrologic conditions, which vary from year, this alternative would provide additional
flood protection for short periods (generally less than 5 years based on recent City experience).
Due to the limited width of the channel and the constrictions at the Marsh Street Bridge and
Bianchi Lane Bridge, under this alternative only modest, temporary increases in flood capacity
could be achieved. This alternative would reduce short-term construction-related impacts to
biological resources, air quality, and noise. This alternative would not meet the project
objectives nor result in long-term beneficial impacts to biological resources - reduction of
invasive species and improved habitat features for aquatic species - that are anticipated under
the proposed project.
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6.5.1 Phased Project Alternative
An alternative that would potentially reduce the short-term construction impacts resulting from
the project is the Phased Project Alternative. This alternative would split the project into three
phases of roughly equal length. For example, Phase 1 would include the project components
from Madonna Road upstream to the downstream end of the Bianchi Bypass. Phase 2 would
include the Bianchi Bypass and Bridge. Phase 3 would include the Pinch Point, Flow Return and
Marsh Street Bridge components. Each of these phases would covers approximately a 1,000
foot-long stretch of the creek. A 3-phase project would potentially result in the following impact
reductions:
x Annual emissions from construction activities would potentially reduce by approximately
one-third in any given year; however, cumulatively emissions would equal those
resulting from a single phase project.
x Assuming South Phase truck traffic would use the Madonna Road/Highway 101 ramps
and the North Phase truck traffic would use the Marsh Street/Highway 101 ramps for the
northern half of the project, short-term noise and traffic impacts would potentially be
limited to one portion of Higuera Street per year.
x Tree removal would be reduced in any given year, and revegetation of disturbed areas
could begin before the entire project area is disturbed. In other words, revegetation
started after the conclusion of Phase 1 would already have two years of growth by the
time that Phase 3 was completed and ready to be revegetated.
x The length of the creek segments to be dewatered would be reduced by one-third in any
given year, potentially reducing short-term, direct impacts to aquatic species and water
quality.
In regards to biological resources, the potential of this alternative to reduce impacts are limited
because while the alternative may reduce the total area of disturbance in a single year, the
construction within one phase could still affect the other corridor. For example, with this
alternative there would be multiple years of staging; some overlap in the phases to allow for the
finished grading, dewatering and revegetation efforts; and the Bianchi Lane Bridge may provide
access to the South phase even though it is part of the North Phase project. In that sense,
resources in one phase that are not static and may be sensitive to adjacent disturbance, such
as nesting birds and aquatic wildlife, may be impacted by construction in both phases.
6.6 Environmentally Superior Alternative
As proposed, the project would not result in any significant and unavoidable impacts; therefore,
any alternative that is environmentally superior would be one that potentially avoids impacts or
substantially lessen those impacts which would be less than significant with mitigation (Class II).
As described above and shown in Table 6.1, the Phased project would potentially spread the
impacts over a longer period and therefore reduce the severity of the impacts in any given year.
However, due to the relatively short length of the corridor and proximity of the operations to the
creek channel, in regards to biological resources, it may be better for the impacts to be focused
in as short a period as possible. The benefits of staging the project over three years do not
appear to present a superior alternative to the proposed project. Therefore, the proposed project
with all mitigations applied may be the environmentally superior alternative, or at least the
environmentally equivalent alternative.
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6.0 Alternatives Analysis 6-4 Mid-Higuera Bypass Project FSEIR Table 6.1 Alternatives Analysis Resource Area Alternatives Comparison Proposed Project No Project Marsh St Bridge Replacement Phased Project Aesthetic Resources Class II Class III – no change from existing conditions Class II – assumes new interchange would require aesthetic resources mitigation/design per Caltrans and City Class II – No change from proposed project Air Quality Class II Class III – less than significant impacts from small sediment removal projects Class I/II – alternative requires significant levels of demolition, grading, concrete and asphalt work. Project would result in emissions rates greater than the proposed project. Class II – reduced annual construction emissions, but similar cumulative emissions to the proposed project Biological Resources Class II Class II – mitigation is typically required by permitting agencies for sediment removal projects Class II – biological resource mitigation required for impacts to the creek below the Marsh Street Bridge. Class II – No overall change to impacts, although the impact to the creek corridor may be less intensive in any given year Cultural Resources Class II Class III – disturbance is generally limited to sediments in the channel and the creek banks where resources are unlikely to exist Class II – no known pre-historic resources; historic resources known in the area; impacts similar to proposed project Class II – No change from proposed project Hazards/ Hazardous Materials Class II Class II – subsurface hazardous materials would not be encountered; however, contaminated soils within the project corridor would remain and potentially leach into the creek. Class II – potential hazardous materials exist subsurface due to long-term use of the area; impacts similar to the proposed project Class II – No change from proposed project Hydrology/Water Quality Class II Class III –flooding continues at current rates Class II – potential impacts similar to the proposed project – erosion control, revegetation, etc plans required Class II – No overall change to impacts, although the potential for erosion and sedimentation impacts to the creek corridor would be less intensive in any given year Noise Class II Class III – no change from current conditions; minor construction-related noise related to sediment removal projects Class I-II – Due to the level of construction required and possible detours onto local roads, noise impacts would be greater than the proposed project. Class II – No change from proposed project Feasibility Feasible Feasible Infeasible within next 10 years due to programming timelines, studies, funding mechanisms Feasible Meets Project Objectives? Yes No Partially - will not improve habitat throughout the corridor Yes Page 123 of 126
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7 References and Preparers
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7.0 References and Preparers
7.1.1 References
Ambient Air Quality and Noise Consulting, Air Quality and Greenhouse Gas Impact Assessment
for the Proposed Mid-Higuera Bypass Project. April 2016.
Ambient Air Quality and Noise Consulting, Noise Impact Assessment for the Proposed Mid-
Higuera Bypass Project. April 2016.
City of San Luis Obispo, General Plan Land Use and Circulation Element Update Program
Environmental Impact Report. September 2014.
City of San Luis Obispo, Mid-Higuera Street Enhancement Plan. March 2001.
City of San Luis Obispo, San Luis Obispo Creek Waterway Management Plan Programmatic
Environmental Impact Report / Environmental Impact Statement. October 2003.
City of San Luis Obispo, San Luis Obispo Creek Waterway Management Plan - Volumes I, II,
and III. March 2003.
County of San Luis Obispo, Archaeological Survey Report Mid-Higuera Bypass Project Flood
Control District Zone 9 San Luis Obispo, San Luis Obispo County. January 2011.
County of San Luis Obispo, Habitat Assessment for the Mid-Higuera Bypass Project;
455R277627. October 2010.
Padre Associates, Phase I Environmental Site Assessment and Preliminary Phase II
Subsurface Assessment Activities for Properties Associated with Proposed Mid-Higuera Bypass
Project. September 2010.
Padre Associates, Report Of Findings Supplemental Soil Assessment Activities Mid-Higuera
Bypass / Flood Control Project. June 2016.
Padre Associates, Tree Survey and Identification of Ordinary High Water Mark within San Luis
Obispo Creek. February 2012.
Padre Associates, Tree Survey and Identification of Ordinary High Water Mark within San Luis
Obispo Creek. November 2013.
Questa Engineering Corporation, Mid-Higuera Flood Control Project Hydrology & Hydraulic
Analysis. July 2009.
SWCA, Mid-Higuera Bypass Flood Control Project Visual Impact Assessment. May 2016.
Wallace Group, Mid-Higuera Bypass Site Plan, Grading Plan, Vegetation Enhancement Plan.
November 2014.
Wallace Group, Project Report Preliminary Design Draft for Review Mid-Higuera Bypass San
Luis Obispo. October 2014.
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7.1.2 EIR Preparers
The primary author of this EIR was Keith Miller, Environmental Resource Specialist with the
County of San Luis Obispo Department of Public Works (Public Works). EIR issue area
assessments were based primarily on background technical resources reports prepared by sub-
consultants including SWCA Environmental Consultants and Padre Associates, and other
Public Works staff, included Kate Ballantyne, Environmental Division Manager, as well as Eric
Weir and Katie Drexhage, Environmental Resource Specialists.
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