HomeMy WebLinkAboutH - PCE Plume Characterization IS-MND November 2024
Groundwater Contamination
Characterization Project
Initial Study – Mitigated Negative Declaration
prepared by
City of San Luis Obispo
Utilities Department
879 Morro Street
San Luis Obispo, California 93401
Contact: Shawna Scott, Special Projects Manager
prepared with the assistance of
Rincon Consultants, Inc.
1530 Monterey Street, Suite D
San Luis Obispo, California 93401
November 2024
Table of Contents
Initial Study – Mitigated Negative Declaration i
Table of Contents
Initial Study .............................................................................................................................................1
1. Project Title .........................................................................................................................1
2. Lead Agency/Project Sponsor Name and Address ..............................................................1
3. Contact Person and Phone Number ...................................................................................1
4. Project Location ..................................................................................................................1
5. General Plan and Zoning Designations ...............................................................................6
6. Description of Project .........................................................................................................6
7. Surrounding Land Uses and Setting ....................................................................................9
8. Other Public Agencies Whose Approval is Required ..........................................................9
9. Have California Native American Tribes Traditionally and Culturally Affiliated with
the Project Area Requested Consultation Pursuant to Public Resources Code
Section 21080.3.1? ........................................................................................................... 10
Environmental Factors Potentially Affected ........................................................................................ 11
Determination ..................................................................................................................................... 11
Environmental Checklist ...................................................................................................................... 13
1 Aesthetics ......................................................................................................................... 13
2 Agriculture and Forestry Resources ................................................................................. 17
3 Air Quality ........................................................................................................................ 19
4 Biological Resources ......................................................................................................... 25
5 Cultural Resources ........................................................................................................... 35
6 Energy .............................................................................................................................. 41
7 Geology and Soils ............................................................................................................. 43
8 Greenhouse Gas Emissions .............................................................................................. 49
9 Hazards and Hazardous Materials ................................................................................... 53
10 Hydrology and Water Quality .......................................................................................... 57
11 Land Use and Planning ..................................................................................................... 61
12 Mineral Resources ........................................................................................................... 63
13 Noise ................................................................................................................................ 65
14 Population and Housing ................................................................................................... 69
15 Public Services .................................................................................................................. 71
16 Recreation ........................................................................................................................ 73
17 Transportation ................................................................................................................. 75
18 Tribal Cultural Resources ................................................................................................. 79
19 Utilities and Service Systems ........................................................................................... 83
20 Wildfire ............................................................................................................................ 87
21 Mandatory Findings of Significance ................................................................................. 89
City of San Luis Obispo
Groundwater Contamination Characterization Project
ii
References ........................................................................................................................................... 95
Bibliography ................................................................................................................................. 95
List of Preparers ........................................................................................................................... 98
Tables
Table 1 Construction Air Quality Thresholds of Significance ........................................................ 20
Table 2 Estimated Criteria Pollutant Emissions During Construction ........................................... 21
Table 3 Plant Species Potential to Occur at The Treatment Well Site .......................................... 26
Table 4 Animal Species Potential to Occur at The Treatment Well Site ....................................... 27
Table 5 Project Consistency with the Climate Action Plan ........................................................... 51
Table 6 Typical Noise Levels for Construction Equipment ........................................................... 66
Figures
Figure 1 Project Overview .................................................................................................................2
Figure 2 Treatment Well Site ............................................................................................................3
Figure 3 Site Photographs – General Project Location .....................................................................4
Figure 4 Site Photographs - Treatment Well Location ......................................................................5
Figure 5 Vegetation Communities and Land Cover Types ............................................................. 28
Appendices
Appendix A Air Quality and Greenhouse Gas Modeling
Appendix B Botanical Memorandum
Appendix C Noise and Vibration Calculations
Initial Study
Initial Study – Mitigated Negative Declaration 1
Initial Study
1. Project Title
Groundwater Contamination Characterization Project
2. Lead Agency/Project Sponsor Name and Address
City of San Luis Obispo
Public Utilities Department
879 Morro Street
San Luis Obispo, California 93401
3. Contact Person and Phone Number
Shawna Scott, Special Projects Manager
City of San Luis Obispo
Public Utilities Department
879 Morro Street
San Luis Obispo, California 93401-3218
4. Project Location
The project is located within the City of San Luis Obispo in San Luis Obispo County, California. The
project site is in the southern portion of the City along U.S. Highway 101 (U.S. 101) between Prado
Road and Los Osos Valley Road within Assessor’s Parcel Numbers 053-051-045, 053-052-045, 053-
131-013, 053-141-012, 053-152-006, 053-152-008, 053-153-014, and 053-153-008.
The approximately 30.4-acre project site encompasses a 22-acre site for the proposed groundwater
extraction and treatment wells and up to 12 potential monitoring locations with a 100-foot
surrounding buffer accounting for the remaining 8.4 acres. Figure 1 and Figure 2 provide a map
illustration of the project components, in a regional and local context. The treatment well site is
identified as a polygon boundary containing two treatment well locations TW-3 and TW-4,1 and the
monitoring well locations are identified as points MW-1 through MW-12. Representative site
photographs are provided in Figure 3 and Figure 4.
1 There are only two treatment wells proposed; however, during earlier planning stages the City considered other well locations in
addition to TW-3 and TW-4.
City of San Luis Obispo
Groundwater Contamination Characterization Project
2
Figure 1 Project Overview
Initial Study
Initial Study – Mitigated Negative Declaration 3
Figure 2 Treatment Well Site
City of San Luis Obispo
Groundwater Contamination Characterization Project
4
Figure 3 Site Photographs – General Project Location
Photograph 1. View of the treatment well site, east of U.S. 101, facing west. Photograph taken on
April 26, 2024.
Photograph 2. View of the treatment well site, east of U.S. 101, facing northeast. Photograph taken on
April 26, 2024.
Initial Study
Initial Study – Mitigated Negative Declaration 5
Figure 4 Site Photographs - Treatment Well Location
Photograph 3. View of the water distribution connection area, west of U.S. 101, facing northeast.
Photograph taken on April 26, 2024.
Photograph 4. View of the treatment well site, east of U.S. 101, facing northeast. Photograph taken on
June 5, 2024.
City of San Luis Obispo
Groundwater Contamination Characterization Project
6
5. General Plan and Zoning Designations
The southern portion of the treatment well site is zoned Conservation/Open Space (C/OS-20) and
has a land use designation of Open Space. The northern portion is zoned Public Facility (PF) and
Public Facility-Special Considerations (PF-S) with a land use designation of Public. Monitoring wells
would be dispersed on City property or within City easements or right-of-way within the following
zones: Conservation/Open Space (C/OS-20), Medium Density Residential (R-2), Low-Density
Residential Specific Plan Overlay (R-1-SP), Public Facility (PF), Service Commercial (C-S), Service
Commercial Mixed Use Overlay (C-S-MU), Service Commercial Planned Development Overlay (C-S-
PD), Retail Commercial (C-R), Retail Commercial Planned development Overlay (C-R-PD), and Tourist
Commercial (C-T). The monitoring wells are on land designated with the following land uses: Service
and Manufacturing, General Retail, Tourist Commercial, Public, Low Density Residential, Medium
Density Residential, and Open Space.
6. Description of Project
The purpose of the project is to clean-up and prevent PCE (tetrachloroethylene) contamination in
drinking water supply wells in the San Luis Valley Subarea of the San Luis Obispo Valley
Groundwater Basin and to expand local water supply resiliency and reduce reliance on local surface
water supplies. In support of these goals, the City of San Luis Obispo proposes to install a network of
monitoring wells and two treatment wells with associated utility infrastructure and a treatment
system to monitor water levels and quality in the Subarea of the Basin, further characterize the PCE
plume, and monitor the effectiveness of removing PCE impacted groundwater from the Subarea of
the Basin. Funding for the implementation phase of the project includes California State Water
Resources Control Board (SWRCB) Proposition 1 Groundwater Grant Program Agreement No.
D2312550.
The project includes 12 possible monitoring well locations and one 22-acre site for the two
proposed extraction treatment wells and the proposed water distribution line. The 12 monitoring
well locations, water conveyance pipelines, and the 22-acre treatment well site collectively
represent the project site. Details for the proposed treatment and monitoring wells are provided
below.
Monitoring Wells
The monitoring wells would be drilled using a hollow-stem auger or rotary sonic drilling method
depending on the location and depth of the proposed location. The installation of the monitoring
wells is anticipated to require an area measuring approximately 40 feet by 10 feet to account for the
drill rig footprint. For the purposes of this assessment, a 100-foot buffer is added to the 40 feet by
10 feet to account for the work zone to accommodate the support truck and decontamination truck,
as well as the work area for the crew.
Construction of the monitoring wells would include:
Each well would be hand augured to a depth of approximately 4 to 8 feet below ground surface
as an additional precautionary method to avoid subsurface utilities or infrastructure.
Each well would consist of one 2-inch or 4-inch diameter, Schedule 40 Polyvinyl Chloride (PVC)
casing.
Initial Study
Initial Study – Mitigated Negative Declaration 7
The annulus between the well casing and the formation would be backfilled with filter pack
(sand) and Portland cement.
A flush-mounted traffic rated steel well box would be installed over each well.
The newly completed monitoring wells would be developed using a combination of bailing,
surging, and pumping.
The wells would likely be 60 to 160 feet deep, with a possibility of a maximum depth of 200 feet.
The boreholes would be 10 inches in diameter, which would produce approximately 50 cubic
feet of cuttings per 100 feet of borehole.
Wastes derived from well installation and well development activities would include soil
cuttings, decontamination water, and development water. Soil cuttings and water would be
containerized in 55-gallon drums, temporarily stored on-site or at an appropriate location, and
profiled for disposal. These investigation-derived wastes would be transported off-site and
disposed of at an appropriate disposal facility in accordance with applicable regulations, if
needed.
As necessary, concrete or asphalt concrete coring would be conducted to penetrate the
concrete surface at each boring location. The concrete coring process would advance a 12-inch
diameter cutter through the concrete. The core would be considered complete when the core
can be removed, and native soil or base fill can be found beneath the concrete slab.
Treatment Wells
Treatment Well #3 (TW-3)
The U.S. 101 well proposed to be equipped for treatment (TW-3) was drilled, constructed, and
tested in February 2003, but has since been capped. The well has a 12-inch casing and is 145 feet
deep, with a 40-foot-deep sanitary seal, set back approximately 300 feet from San Luis Obispo
Creek. The proposed site layout for TW-3 includes new extraction well infrastructure (an
approximately 650-square foot building to house the treatment well, electrical panels, and
disinfection system) as well as the centralized treatment system (treatment pad with granulated
activated carbon (GAC) vessels and bag filters, as well as two backwash storage tanks). The
proposed TW-3 site layout would also include security fencing, utility infrastructure, entailing a new
6-inch sewer line connecting the backwash storage tank to the City’s sanitary sewer system, a new
12-inch water line connecting the treatment infrastructure to the City’s water distribution system,
and a new 8-inch water line connecting TW-3 to the Bob Jones Trail treatment well (TW-4). A gravel
access road would be constructed between TW-3 and an existing gravel road approximately 100
feet west of the TW-3 site to provide access to the TW-3 site. The utility infrastructure would be
installed in the same locations as the gravel access road and underneath the existing disturbed
access road as shown in Figure 3 and Figure 4. The affected area consists of approximately 0.27
acre, including placement of gravel, paving, and structural elements. Construction of this utility
infrastructure and the gravel access road would require the removal of three cypress trees and four
oak trees. Tree removal would occur consistent with the requirements of Chapter 12.24 of the City’s
Municipal Code, including compensatory tree planting and protection of surrounding trees to
remain.
City of San Luis Obispo
Groundwater Contamination Characterization Project
8
Treatment Well #4 (TW-4)
TW-4 would involve drilling, construction, and testing of a new groundwater production well (Bob
Jones Trail Well). The affected area consists of approximately 0.31 acre, including placement of
gravel, paving, and structural elements. The sequence of work would include:
Mobilization to the well site and installation of sound barriers, if identified as a requirement by
the City.
Drilling and installing a 50-foot deep conductor casing, annular materials, and cement seal.
Drilling a pilot borehole to a depth of 205 below ground surface.
Conducting a geophysical logging and deviation survey of the completed pilot borehole, and
submitting formation samples selected by the City to a testing laboratory for grain size
distribution analysis.
Reaming the pilot borehole to the diameter and depth per final well design.
Construction of the well, including mechanical, chemical, and pumping well development.
Conducting well testing, including production tests, groundwater sampling and flowmeter
survey, and video camera survey and plumbness/alignment survey.
Disinfection of well casing and installation of well casing and tubing end caps.
Demobilization, clean-up, and restoration of the well site. Restoration would include restoring
the well location to pre-existing conditions in accordance with City Standard Specifications and
Engineering Standards, and replacing plants and groundcover temporarily affected by the
construction activities.
The TW-4 site layout would include perimeter security fencing, paving, and a 250-square-foot, one-
story secure building to house the well and electrical panels. The building would be configured with
a removable roof (or hatch) for future well maintenance. In addition, TW-4 includes a new gravel
access road, connecting the TW-4 location to the existing Bob Jones Trail.
Construction Schedule/Staging/Equipment
Construction of the monitoring wells is anticipated to occur from April 2025 to October 2025.
Drilling of TW-4 is anticipated to occur from March 2025 to August 2025. Well equipping 2 would
begin in June 2025 and would be completed in July 2026. Construction of the TW-3 site would occur
between August 2025 and February 2026. Construction of the TW-4 site would occur between
August 2025 and February 2026. Construction activities would generally occur within the City’s
permitted hours between 7:00am and 7:00pm Monday through Saturdays. However, some
construction activities may necessitate work outside of these hours in the event utility infrastructure
is shut off during the day but must be made operational the next day (e.g., water lines). Well drilling
is expected to last 40 days, and major Project construction activities associated with the
development of the TW sites visible from U.S. 101 would last approximately 120 working days.
All work would be conducted on City property or within City easement or right-of-way. Access to
TW-4 would be provided by approximately 200 feet of new gravel access road in two approximately
100-foot segments, connecting the TW-4 location to the existing Bob Jones Trail. No work would
occur within Caltrans right-of-way. The following equipment is anticipated for all work: bucket auger
drill rig for conductor, tremie pipe, cement truck and concrete pump (conductor casing), hand
auger, hollow-stem auger or rotary sonic drill, support/water and decontamination truck,
2 Well equipping refers to the process of outfitting a drilled well with all necessary components to make the well operational.
Initial Study
Initial Study – Mitigated Negative Declaration 9
decontamination trailer, forklift or backhoe, Baker tank(s) for development water, roll off
bins/drums for soil.
A plastic tarp and containment berm would be placed beneath the drilling rig during mobilization to
protect the site against oil or hydraulic fluid spills or leaks and would remain beneath the rig until
demobilization. A plastic tarp of the same thickness and containment berm would also be placed
beneath other stationary equipment such as air compressors and fuel tanks. Containment berm
protection for any fuel tanks would be equal to or greater than the maximum fuel capacity of the
tank(s).
Soil Disposal
Approximately 45 cubic yards of drill cuttings and approximately 7,400 gallons of drilling mud would
be generated at TW-4. Up to approximately 4 cubic yards of drill cuttings would be generated at
each monitoring well site. The total volume of drill cuttings is expected to be up to approximately
90-100 cubic yards. The construction contractor would be required to contain and store all
investigation-derived waste, including drill cuttings and drilling mud. Cuttings would not be allowed
to be stored on the ground due to the potential for the presence of PCE.
The construction contractor would be required to submit samples of drilling spoils for analytical
testing required for waste profiling. Based on the results of the analytical testing the drilling spoils
will be containerized, transported, and disposed of at the appropriate waste disposal facility. The
construction contractor would complete appropriately required waste disposal manifests and bills
of lading and submit such documents to the City of San Luis Obispo for signature and approval prior
to transporting waste from each monitoring well site. The construction contractor would furnish to
the City one original waste disposal manifest signed and certified by the disposal facility confirming
the volume and receipt of waste materials.
7. Surrounding Land Uses and Setting
The treatment well site is surrounded by U.S. 101 and commercial development to the north and
west, the City Water Resource Recovery Facility (WRRF) to the north, and San Luis Obispo Creek to
the east and south. U.S. 101 is partially included within the treatment well site, but no work is
proposed as part of the project that would directly affect U.S. 101 or occur in the U.S. 101 right-of-
way. The monitoring well sites are primarily located in developed residential and commercial
portions of the City.
8. Other Public Agencies Whose Approval is Required
The City of San Luis Obispo is the lead agency with approval over the proposed project. The City will
obtain permits from the County of San Luis Obispo for the new extraction well and each monitoring
well. The project will require approval from the California Department of Drinking Water.
City of San Luis Obispo
Groundwater Contamination Characterization Project
10
9. Have California Native American Tribes Traditionally
and Culturally Affiliated with the Project Area
Requested Consultation Pursuant to Public Resources
Code Section 21080.3.1?
Native American Tribes were notified on July 25, 2024 about the project consistent with City and
State regulations including, but not limited to, Assembly Bill 52. During the request for consultation
window, two responses were received. The Santa Ynez Band of Chumash Indians contacted the City
on August 5, 2024 requesting a consultation meeting to discuss the project. The City consulted with
the Tribe on September 17, 2024 and shared information regarding the project, the results of the
cultural resources survey, and proposed mitigation measures. The Tribe informed the City that they
are in agreement with the mitigation measures laid out in the public review Draft IS-MND for a
workers environmental awareness program training, archaeological monitoring, and protocol in the
event of unanticipated discoveries. The Salinan Tribe of Monterey responded on August 30, 2024
requesting notification in the event of a cultural resource discovery during construction. Pursuant to
PRC §21080.3.1 (b) the request for consultation window closed on August 26, 2024. No other tribal
agencies responded to the consultation request.
Environmental Factors Potentially Affected
Initial Study – Mitigated Negative Declaration 11
Environmental Factors Potentially Affected
This project would potentially affect the environmental factors checked below, involving at least
one impact that is “Potentially Significant” or “Less than Significant with Mitigation Incorporated” as
indicated by the checklist on the following pages.
■ Aesthetics □ Agriculture and
Forestry Resources
■ Air Quality
■ Biological Resources ■ Cultural Resources □ Energy
■ Geology and Soils □ Greenhouse Gas
Emissions
□ Hazards and Hazardous
Materials
□ Hydrology and Water
Quality
□ Land Use and Planning □ Mineral Resources
■ Noise □ Population and
Housing
□ Public Services
□ Recreation □ Transportation ■ Tribal Cultural Resources
□ Utilities and Service
Systems
□ Wildfire ■ Mandatory Findings
of Significance
Determination
Based on this initial evaluation:
□ I find that the proposed project COULD NOT have a significant effect on the environment,
and a NEGATIVE DECLARATION will be prepared.
■ I find that although the proposed project could have a significant effect on the environment,
there will not be a significant effect in this case because revisions to the project have been
made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION will
be prepared.
□ I find that the proposed project MAY have a significant effect on the environment, and an
ENVIRONMENTAL IMPACT REPORT is required.
□ I find that the proposed project MAY have a “potentially significant impact” or “less than
significant with mitigation incorporated” impact on the environment, but at least one effect
(1) has been adequately analyzed in an earlier document pursuant to applicable legal
standards, and (2) has been addressed by mitigation measures based on the earlier analysis
as described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but it
must analyze only the effects that remain to be addressed.
City of San Luis Obispo
Groundwater Contamination Characterization Project
12
□ I find that although the proposed project could have a significant effect on the environment,
because all potential significant effects (a) have been analyzed adequately in an earlier EIR
or NEGATIVE DECLARATION pursuant to applicable standards, and (b) have been avoided or
mitigated pursuant to that earlier EIR or NEGATIVE DECLARATION, including revisions or
mitigation measures that are imposed upon the proposed project, nothing further is
required.
Signature Date
Printed Name Title
Environmental Checklist
Aesthetics
Initial Study – Mitigated Negative Declaration 13
Environmental Checklist
1 Aesthetics
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Except as provided in Public Resources Code
Section 21099, would the project:
a. Have a substantial adverse effect on a
scenic vista? □ □ ■ □
b. Substantially damage scenic resources,
including but not limited to, trees, rock
outcroppings, and historic buildings
within a state scenic highway? □ □ ■ □
c. In non-urbanized areas, substantially
degrade the existing visual character or
quality of public views of the site and its
surroundings? (Public views are those
that are experienced from a publicly
accessible vantage point). If the project is
in an urbanized area, would the project
conflict with applicable zoning and other
regulations governing scenic quality? □ □ ■ □
d. Create a new source of substantial light or
glare that would adversely affect daytime
or nighttime views in the area? □ ■ □ □
Environmental Setting
The project site is located in the San Luis Valley, within the southern portion of the City of San Luis
Obispo, in San Luis Obispo County, California. The topography of the treatment well site is relatively
flat, with an approximate elevation ranging from 111 to 126 feet above mean sea level, sloping
southward, with an average slope of 2 percent. Immediately surrounding land uses include
transportation/roadways, including U.S. 101 and commercial development to the north and west,
the City WRRF to the north, and San Luis Obispo Creek to the east and south (refer to Figure 2). San
Luis Obispo Creek is immediately east and parallel to the eastern boundary of the treatment well
site and Laguna Lake is approximately 0.6 mile to the northwest. The treatment well site is located
on vegetative grasses and open space (refer to Figure 1). The monitoring well sites are located
throughout the City, on City property or within City easements or right-of-way. The majority of the
monitoring well locations are paved, except for MW-4, which is located on aggregate and topsoil.
City of San Luis Obispo
Groundwater Contamination Characterization Project
14
The nearest officially designated state scenic highway, State Route 1,3 is approximately three miles
north of the treatment well site. There is no line of sight between this portion of State Route 1 and
the treatment well site. West of the treatment well site, State Route 1 and U.S. 101 converge and
share a designation of an Eligible Scenic Highway (Caltrans 2019). The City identifies the portion of
U.S 101 adjacent to the treatment well site as having high scenic value. However, no scenic vistas
are identified through the treatment well site. The nearest scenic vista is located 0.6 mile north,
with north facing views from Madonna Road (City of San Luis Obispo 2014a).
Impact Analysis
a. Would the project have a substantial adverse effect on a scenic vista?
b. Would the project substantially damage scenic resources, including but not limited to, trees,
rock outcroppings, and historic buildings within a state scenic highway?
The project site is not located in an area with an identified scenic vista. The project site is not visible
from or located within the viewsheds experienced at Madonna Road (i.e., views of Laguna Lake
Park, Irish Hills Natural Preserve, and Cerro San Luis) or any other designated scenic vista. Although
the treatment well site is located along a high scenic value portion of State Route 1/U.S. 101, which
is an Eligible Scenic Highway, project construction activities visible from U.S. 101 would be
temporary, lasting approximately 120 working days. These temporary construction activities would
not restrict views of scenic vistas through the treatment well site. Following construction
completion, the treatment wells and associated structural infrastructure would not preclude views
of surrounding scenic vistas as the height of proposed infrastructure would not pose substantial
impediments to existing views. The monitoring wells do not include any development or structures;
work would be conducted in the subsurface. Post completion, a flush-mounted traffic rated steel
well box would be installed over each monitoring well. Therefore, the monitoring wells would not
provide any visual impediments to surrounding scenic vistas.
There are no rock outcroppings, or historic buildings at the treatment well site locations, and no
rock outcropping, or historic buildings would be modified or otherwise impacted as a result of the
project. The project would remove seven trees to install the access road and utility infrastructure.
The treatment well site and surroundings are lined with trees along San Luis Obispo Creek and the
minimal tree removal required for the project would not have a substantial adverse effect on public
views from U.S. 101 or the surrounding area.
The project would not include infrastructure with the potential to substantially affect views of scenic
vistas and no rock outcropping, or historic buildings would be modified or otherwise impacted as a
result of the project. The project would not have a substantial adverse effect on a scenic vista or
damage scenic resources within a state scenic highway. Therefore, these impacts would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
3 State Route 1 is officially designated as a scenic highway starting at the intersection of Santa Rosa Street and Highland Drive. At its
convergence with U.S. 101 adjacent to the treatment well site it is designated as an eligible state scenic highway.
Environmental Checklist
Aesthetics
Initial Study – Mitigated Negative Declaration 15
c. Would the project, in an urbanized area, conflict with applicable zoning and other regulations
governing scenic quality?
The project site is adjacent to commercial, residential, public facilities uses, and U.S. 101. Given the
population density of the City of San Luis Obispo, and the developed nature of the project site and
its surroundings, the project is evaluated as an urban area consistent with CEQA Guidelines Section
15387.4 Therefore, this discussion examines if the project would conflict with City zoning and other
regulations governing scenic quality.
The southern portion of the treatment well site is zoned Conservation/Open Space (C/OS-20), and
the northern portion is zoned Public Facility (PF) and Public Facility-Special Considerations (PF-S).
The monitoring wells would not introduce above-ground infrastructure, and therefore, would not
result in conflicts with regulations related to scenic quality. The treatment wells would introduce
new above-ground infrastructure to the treatment well site such as perimeter security fencing,
buildings to house each well and electrical panels, two GAC vessels, and two storage tanks within
the Conservation/Open Space (C/OS-20), Public Facility (PF) and Public Facility-Special
Considerations (PF-S) zones. These zones permit public service infrastructure. The proposed project
would not interfere with established setbacks in these zones and would not exceed height
requirements or otherwise interfere with regulations governing scenic quality in these zones. The
project would not conflict with applicable zoning and other regulations governing scenic quality or
substantially degrade existing visual character or quality. Therefore, this impact would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
d. Would the project create a new source of substantial light or glare that would adversely affect
daytime or nighttime views in the area?
Pursuant to Municipal Code Section 9.12.050, construction work is limited to daytime hours
between 7:00 a.m. and 7:00 p.m. unless discretionary approval for nighttime work is granted by the
City’s Community Development Department. Daytime work would not require the use of temporary
flood lights or other light/glare generating sources during the day. Nighttime work, if necessary,
would be carried out in accordance with lighting provisions set forth by the City’s Community
Development Department. However, nighttime construction work would have the potential to
constitute a temporary source of new light that may affect nighttime views. This impact would be
potentially significant.
Once construction activities are completed, potential sources of light may include shielded security
lighting. Any exterior lighting would be required to be consistent with the City’s Lighting and Night
Sky Preservation standards, which require that outdoor lighting is fully shielded and directed
downward and away from adjacent properties and public rights-of-way. Therefore, operation of the
project would not create a new source of substantial light or glare which would adversely affect day
or nighttime views in the area, and this impact would be less than significant.
4 The population of San Luis Obispo is approximately 48,684 (California Department of Finance 2024). CEQA Guidelines Section 15387
provides that an urbanized area means a city with a population of 50,000 or an area having a population density of at least 1,000 persons
per square mile. San Luis Obispo is approximately 13.2 square miles, providing a population density of approximately 3,688 persons per
square mile. Therefore, San Luis Obispo meets the criteria of an urbanized area pursuant to CEQA Guidelines 15387.
City of San Luis Obispo
Groundwater Contamination Characterization Project
16
Mitigation Measures
AES-1 Nighttime Work Requirements
In the event nighttime work is necessary during the project construction phase, any portable lighting
shall be shielded and/or directed away from adjacent properties. Night lighting for construction
activities shall be the minimum necessary to ensure safety and security for nighttime activities and
operations. Lighting at the project site shall consist of light-emitting diode lights in all areas where
nighttime construction activities will occur and be either motion-activated or use timers to ensure
safety and security and reduce the impact of additional light pollution at night. The City shall verify
compliance with the construction night lighting requirements via an inspection during nighttime
construction activities.
Significance After Mitigation
Implementation of AES-1 would reduce potential project impacts related to nighttime lighting to a
less than significant level by requiring shielding of lighting.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
Environmental Checklist
Agriculture and Forestry Resources
Initial Study – Mitigated Negative Declaration 17
2 Agriculture and Forestry Resources
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Convert Prime Farmland, Unique Farmland,
or Farmland of Statewide Importance
(Farmland), as shown on maps prepared
pursuant to the Farmland Mapping and
Monitoring Program of the California
Resources Agency, to non-agricultural use? □ □ □ ■
b. Conflict with existing zoning for agricultural
use or a Williamson Act contract? □ □ □ ■
c. Conflict with existing zoning for, or cause
rezoning of, forest land (as defined in
Public Resources Code Section 12220(g));
timberland (as defined by Public Resources
Code Section 4526); or timberland zoned
Timberland Production (as defined by
Government Code Section 51104(g))? □ □ □ ■
d. Result in the loss of forest land or
conversion of forest land to non-forest
use? □ □ □ ■
e. Involve other changes in the existing
environment which, due to their location
or nature, could result in conversion of
Farmland to non-agricultural use or
conversion of forest land to non-forest
use? □ □ ■ □
Environmental Setting
The California Department of Conservation’s (DOC) Farmland Mapping and Monitoring Program
classifies the treatment well site and each of the 12 monitoring well locations as Urban and Built-Up
Land, which is defined as land that is occupied by structures with a building density of at least one
unit to 1.5 acres (DOC 2022). The treatment well site is zoned Conservation/Open Space (C/OS-20),
Public Facility (PF) and Public Facility-Special Considerations (PF-S). The treatment and monitoring
well sites are not located within active agricultural uses, land zoned for agriculture, or classified
forest land (City of San Luis Obispo 2014a).
City of San Luis Obispo
Groundwater Contamination Characterization Project
18
Impact Analysis
a. Would the project convert Prime Farmland, Unique Farmland, or Farmland of Statewide
Importance (Farmland), as shown on maps prepared pursuant to the Farmland Mapping and
Monitoring Program of the California Resources Agency, to non-agricultural use?
b. Would the project conflict with existing zoning for agricultural use or a Williamson Act
contract?
Construction equipment and well sites would be staged within individual work zones on City
property or within City easement or right-of-way. No portions of the project are located on land
designated as Prime Farmland, Unique Farmland, or Farmland of Statewide Importance as mapped
by the DOC (DOC 2022). As such, there is no potential for the project to convert such lands to non-
agricultural uses. No portions of the project are currently zoned for agriculture or held under
Williamson Act or any other land conservation contract. The project would not convert Farmland or
conflict with existing zoning for agricultural use or a Williamson Act contract. Therefore, no impact
would occur.
NO IMPACT
c. Would the project conflict with existing zoning for, or cause rezoning of, forest land (as defined
in Public Resources Code Section 12220(g)); timberland (as defined by Public Resources Code
Section 4526); or timberland zoned Timberland Production (as defined by Government Code
Section 51104(g))?
d. Would the project result in the loss of forest land or conversion of forest land to non-forest use?
No portions of the project are located on land that is in current timberland production, including
any lands designated as forest land or timberland. Therefore, the project would not conflict with
existing zoning for forest land, timberland, or timberland zoned Timberland Production, or result in
the loss of forest land or conversion of forest land to non-forest use. No impact would occur.
NO IMPACT
e. Would the project involve other changes in the existing environment which, due to their
location or nature, could result in conversion of Farmland to non-agricultural use or conversion
of forest land to non-forest use?
No portions of the project are located on forest land or timberland. The portion of the project
adjacent to the City Farm and San Luis Ranch agricultural area would be located within an existing
easement, and within an existing access road along Highway 101; furthermore, infrastructure would
be below ground, consisting of an underground water distribution pipe. No lands under cultivation
would be affected by the project. Therefore, the project would not result in the conversion of
Farmland to non-agricultural use or conversion of forest land to non-forest use. Impacts would be
less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Air Quality
Initial Study – Mitigated Negative Declaration 19
3 Air Quality
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Conflict with or obstruct implementation
of the applicable air quality plan? □ □ □ ■
b. Result in a 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? □ □ ■ □
c. Expose sensitive receptors to substantial
pollutant concentrations? □ □ ■ □
d. Result in other emissions (such as those
leading to odors) adversely affecting a
substantial number of people? □ ■ □ □
Environmental Setting
The project site is located in the South Central Coast Air Basin (SCCAB) which covers San Luis Obispo,
Santa Barbara, and Ventura counties (California Air Resources Board [CARB] 2014). The San Luis
Obispo Air Pollution Control District (SLOAPCD) monitors and regulates the local air quality in San
Luis Obispo County and enforces the Clean Air Plan. SLOAPCD is required to monitor air pollutant
levels to ensure that National Ambient Air Quality Standards (NAAQS) and California Ambient Air
Quality Standards (CAAQS) are met and, if they are not met, to develop strategies to meet the
standards.
Depending on whether the standards are met or exceeded, the SCCAB is classified as being in
“attainment” or “nonattainment” for air quality. The SCCAB is in nonattainment for the federal
standards for ozone (eastern San Luis Obispo County only) and the state standards for ozone, and
particulate matter less than 10 microns in diameter (PM10). The SCCAB is designated in attainment
for all other federal and state standards (SLOAPCD 2019).
SLOAPCD is required to prepare a plan for air quality improvement for pollutants for which its
jurisdiction is in nonattainment. Because the SCCAB is currently designated nonattainment for
federal and State standards for ozone and State standards for PM10, SLOAPCD is required to
implement strategies that would reduce pollutant levels to recognized acceptable standards.
SLOAPCD adopted the Clean Air Plan in 2001 which evaluates long-term emissions and establishes
programs to reach acceptable air quality levels (SLOAPCD 2001). SLOAPCD has also adopted the
Particulate Matter Report to identify strategies to reduce public exposure to particulate matter, and
the Ozone Emergency Episode Plan which provides the basis for taking action when ambient ozone
concentrations reach a level that poses a threat to public health in the County (SLOAPCD 2005;
SLOAPCD 2020).
City of San Luis Obispo
Groundwater Contamination Characterization Project
20
SLOAPCD provides numerical thresholds to analyze the significance of a project’s construction and
operational impacts on regional air quality. These thresholds, listed in Table 1, are designed such
that a project with estimated emissions that do not exceed the thresholds would not have an
individually or cumulative significant impact on the air quality of the SCCAB.
Table 1 Construction Air Quality Thresholds of Significance
Threshold
Pollutant
Daily
(pounds per day)
Quarterly Tier 1
(tons per quarter)
Quarterly Tier 2
(tons per quarter)
ROG + NOx (combined) 137 2.5 6.3
Diesel Particulate Matter (DPM) 7 0.13 0.32
Fugitive Particulate Matter (PM10), Dust – 2.5 –
ROG = Reactive Organic Gases; NOx = Nitrous Oxides
Source: SLOAPCD 2023
Sensitive receptors typically include residences, schools, healthcare facilities, and other live-in
housing facilities such as prisons or dormitories. The closest sensitive receptors to the monitoring
wells include single-family residences located approximately 15 feet east of MW-10, a single-family
residence located approximately 45 feet north of MW-06, a single-family residence located
approximately 50 feet east of MW-01, and mobile homes located approximately 65 feet north of
MW-03. The closest sensitive receptors to the treatment well site are single-family residences
located approximately 245 feet east of the treatment well site. The portion of the Bob Jones Trail
within the treatment well site is a recreational use which is not considered a sensitive receptor.
Impact Analysis
a. Would the project conflict with or obstruct implementation of the applicable air quality plan?
The applicable air quality plan is the SLOAPCD Clean Air Plan. Based on SLOAPCD’s CEQA Air Quality
Handbook (2023), if a project is consistent with the land use assumptions and transportation control
measures within the Clean Air Plan, the project would be consistent with the Clean Air Plan
(SLOAPCD 2023). The transportation control measures within the Clean Air Plan are primarily
related to providing alternative transportation options, enhancing bike infrastructure, and
circulation management (SLOAPCD 2001). Because the proposed project would not result in
population growth or result in changes to existing City land use designations or long-term
transportation patterns, the transportation control measures in the Clean Air Plan are not directly
applicable to the proposed project, and the proposed project would not conflict with the population
projections and land use assumptions of the Clean Air Plan. Therefore, the proposed project would
not conflict with or obstruct implementation of SLOAPCD’s Clean Air Plan, and no impact would
occur.
NO IMPACT
Environmental Checklist
Air Quality
Initial Study – Mitigated Negative Declaration 21
b. Would the project result in a 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?
The California Emissions Estimator Model (CalEEMod), version 2022.1.1.22 was used to estimate the
project’s air pollution emissions. CalEEMod uses project-specific information, including a project’s
land uses, construction equipment parameters, and location, to model a project’s construction
emissions. Operation of the proposed project would generate a nominal amount of air pollutants
from minimal electricity consumption and vehicle trips to the well sites for maintenance activities
and would not result in substantial air pollutant emissions or generate a cumulatively considerable
net increase of any criteria pollutant for which the SCCAB is in nonattainment. Therefore, for the
purposes of this analysis, only construction emissions were modeled and compared to SLOAPCD
construction emission thresholds. CalEEMod modeling outputs are included in Appendix A.
Table 2 shows the proposed project’s estimated criteria air pollutant emissions and compares the
emissions to SLOPACD thresholds. Construction of the proposed project would not exceed SLOAPCD
construction thresholds and would not result in a cumulatively considerable net increase of any
criteria pollutant for which the SCCAB is in nonattainment. Therefore, this impact would be less than
significant.
Table 2 Estimated Criteria Pollutant Emissions During Construction
Estimated Emissions
ROG NOx CO SO2 PM10 PM2.5
Construction Emissions (pounds per day) 6.3 48.0 55.7 0.2 1.9 1.6
Construction Emissions (tons per quarter) 0.1 0.6 0.7 <0.01 0.03 0.02
SLOAPCD Thresholds (Daily) 137 pounds per day
(combined ROG
and NOx)
N/A N/A N/A 7 pounds
per day
SLOAPCD Thresholds (Quarterly) 2.5 tons
(combined ROG
and NOx)
N/A N/A 2.5 tons 0.13 tons
Thresholds Exceeded? No N/A N/A No No
ROG = reactive organic gases; NOX = nitrogen oxides; CO = carbon monoxide; SO2 = sulfur dioxide; PM10 = particulate matter 10
microns or less in diameter; PM2.5 = particulate matter 2.5 microns or less in diameter
Source: SLOAPCD 2023; Appendix A
LESS-THAN-SIGNIFICANT IMPACT
c. Would the project expose sensitive receptors to substantial pollutant concentrations?
Fugitive Dust
Most of the proposed monitoring wells would be located in paved areas with minimal potential to
generate substantial fugitive dust. However, MW-11 would be constructed approximately 815 feet
from single-family residences, and TW-3, TW-4, and MW-09 would be constructed approximately
450 west of single-family residences. As described in Threshold 3(b), the project would not result in
particulate matter emissions that would exceed SLOAPCD’s regional thresholds. Construction
personnel would be required to adhere to California Code of Regulations Title 13 Section 2485,
which prohibits idling of diesel-powered vehicles for over five minutes to minimize diesel particulate
City of San Luis Obispo
Groundwater Contamination Characterization Project
22
matter emissions. In addition to these requirements, SLOAPCD guidelines require projects that
would disturb greater than four acres within 1,000 feet of a sensitive receptor to implement
standard mitigation measures to minimize fugitive dust emissions (SLOAPCD 2023). For project
construction activities at all sites, the City’s Special Provisions and specifications would require the
contractor implement applicable SLOAPCD fugitive dust measures as best management practices to
minimize localized fugitive dust emissions during construction. These measures include, but are not
limited to, watering to prevent airborne dust, stabilization of soils, limiting vehicle speeds on the
project site, and use of devices to prevent sand or dirt from falling out of trucks during transport
(SLOAPCD 2023). With the inclusion and implementation of SLOAPCD’s standard mitigation for
fugitive dust emissions reduction, the proposed project’s potential to expose sensitive receptors to
substantial fugitive dust emissions would be less than significant.
Naturally Occurring Asbestos
Naturally occurring asbestos (NOA) has been identified by CARB as a toxic air contaminant.
Serpentinite and ultramafic rocks are common throughout San Luis Obispo and may contain
naturally occurring asbestos (SLOAPCD 2018). Under CARB’s Air Toxic Control Measures related to
construction and grading, a geologic evaluation is required to determine of NOA is present prior to
any grading activities at the project site. If NOA is identified at the site during ground-disturbing
activities, requirements outlined in CARB’s Air Toxic Control Measures would be enforced, in
addition to requirements stipulated in the National Emission Standard for Hazardous Air Pollutants
(40 Code of Federal Regulations Section 61, Subpart M -Asbestos). These requirements include
notifying SLOAPCD at least 10 days prior to commencing construction, preparing an asbestos survey
conducted by a Certified Asbestos Consultant, and implementation of removal and disposal protocol
and requirements for identified NOA. A SLOAPCD Permit to Operate for Excavation of Contaminated
Soils is included in the City’s Standard Specifications and Engineering Standards (August 2020). This
Permit states that required Naturally Occurring Asbestos and NESHAP requirements have been met,
and monitoring, recordkeeping, and District notification procedures are in place. With adherence to
the SLOAPCD permit and State requirements for NOA abatement, the proposed project would have
a less than significant impact on sensitive receptors due to the presence of NOA.
LESS-THAN-SIGNIFICANT IMPACT
d. Would the project result in other emissions (such as those leading to odors) adversely affecting
a substantial number of people?
The project would not involve operation of any land uses identified by SLOAPCD that may generate
substantial odors, such as asphalt batch plants, chemical manufacturing, sanitary landfill, or a
wastewater treatment plant (SLOAPCD 2023). Construction would generate temporary odors
associated with diesel exhaust emitted by construction equipment. These odors would be localized
to the project site and restricted to the duration of equipment use, which would be temporary and
infrequent. The distances between both treatment well sites and receptors and most monitoring
well sites and receptors are generally large enough such that construction would not result in
nuisance due to odors. In addition, construction personnel would be required to adhere to idling
restrictions for on- and off-road vehicles and equipment which would minimize diesel odors.
However, due to the proximity of MW-01, MW-06, and MW-10 to single-family residences, there is
potential that construction of these monitoring wells could result in short-term nuisance due to
odors at nearby residences. This impact would be potentially significant.
Environmental Checklist
Air Quality
Initial Study – Mitigated Negative Declaration 23
Mitigation Measure
AQ-1 Odor Reduction
Where construction activities occur within 50 feet of a sensitive receptor, the construction
contractor shall implement the following additional idling restrictions, which shall be shown on
grading and construction plans:
Idling Restrictions Near Sensitive Receptors for Both On- and Off-Road Equipment
Staging and queuing areas shall be located at the greatest distance feasible from sensitive
receptor locations;
Diesel idling while equipment is not in use is not permitted;
Use of alternative-fueled equipment is recommended whenever possible; and
Signs that specify the no-idling requirements shall be posted and enforced at the
construction site.
The City Utilities Department shall verify these measures are located on construction plans prior to
the start of construction. Once during construction, City Inspector shall visit the project site to verify
these idling restrictions have been implemented.
Significance After Mitigation
Implementation of Mitigation Measure AQ-1 would ensure construction within 50 feet of sensitive
receptors would not result in substantial odors affecting the adjacent single-family residence
through implementation of idling restrictions. Implementation of Mitigation Measure AQ-1 would
reduce the proposed project’s impact related to odors to a less than significant level.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
City of San Luis Obispo
Groundwater Contamination Characterization Project
24
This page intentionally left blank.
Environmental Checklist
Biological Resources
Initial Study – Mitigated Negative Declaration 25
4 Biological Resources
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Have a substantial adverse effect, either
directly or through habitat modifications,
on any species identified as a candidate,
sensitive, or special status species in local
or regional plans, policies, or regulations, or
by the California Department of Fish and
Wildlife or U.S. Fish and Wildlife Service? □ ■ □ □
b. Have a substantial adverse effect on any
riparian habitat or other sensitive natural
community identified in local or regional
plans, policies, or regulations, or by the
California Department of Fish and Wildlife
or U.S. Fish and Wildlife Service? □ □ ■ □
c. Have a substantial adverse effect on state
or federally protected wetlands (including,
but not limited to, marsh, vernal pool,
coastal, etc.) through direct removal, filling,
hydrological interruption, or other means? □ □ ■ □
d. Interfere substantially with the movement
of any native resident or migratory fish or
wildlife species or with established native
resident or migratory wildlife corridors, or
impede the use of native wildlife nursery
sites? □ □ ■ □
e. Conflict with any local policies or
ordinances protecting biological resources,
such as a tree preservation policy or
ordinance? □ □ ■ □
f. Conflict with the provisions of an adopted
Habitat Conservation Plan, Natural
Community Conservation Plan, or other
approved local, regional, or state habitat
conservation plan? □ □ □ ■
Rincon prepared a Botanical Survey Memorandum (Botanical Memorandum, Appendix B) in June
2024 to summarize methodology and results of protocol-level botanical surveys and literature
review to determine presence or absence of federally and/or State-listed or other special-status
City of San Luis Obispo
Groundwater Contamination Characterization Project
26
plant species within the treatment well site. Surveys were carried out in accordance with the
California Native Plant Survey’s (CNPS) Botanical Survey Guidelines and the California Department of
Fish and Wildlife’s (CDFW) Protocols for Surveying and Evaluating Impacts to Special Status Native
Plant Populations and Natural Communities. The botanical surveys were conducted in April and June
of 2024, and were timed to capture the flowering periods of all special-status plant species
determined to have a low, moderate, or high potential to occur on-site based on the literature
review and regionally specific knowledge. The monitoring well locations were not evaluated for the
potential to support sensitive plant or animal species, or other potentially significant biological
resources, as each of the monitoring well locations outside of the treatment well site would be
developed on locations that are paved and feature existing infrastructure (as confirmed based on
site visits conducted by City staff), and thus do not present the potential for encountering sensitive
biological resources.
In addition, in July 2024, Rincon conducted a review of the California Natural Diversity Database
(CNDDB) using a 5-Mile radius buffer, a review of the CNPS inventory, and completed an evaluation
of the species-specific potential to occur at the treatment well site, based on a site visit on July 15,
2024 and the CNDDB/CNPS results (also included in Appendix B). The setting and impact analysis
provided are summarized based on the results of the Botanical Memorandum and CNDDB
documentation.
Environmental Setting
Plant Species
The CNDDB and CNPS identified 121 special-status plant and lichen species with documented
occurrences within a five-mile radius of the treatment well site. Of these plant and lichen species, 11
have a low potential to occur, five have a moderate potential to occur, and four have a high
potential to occur at the treatment well site.
Table 3 provides an overview of the CNDDB and CNPS results for species with moderate and high
potential to occur.
Table 3 Plant Species Potential to Occur at The Treatment Well Site
Species
Potential
to Occur
Potentially Suitable Habitat
Present at Treatment Well Site
club-haired mariposa-lily (Calochortus clavatus var. clavatus) High Yes
Cambria morning-glory (Calystegia subacaulis ssp. episcopalis) High Yes
San Luis Obispo owl’s-clover (Castilleja densiflora var. obispoensis) High Yes
Jones’ layia (Layia jonesii) High Yes
Congdon’s tarplant (Centromadia parryi ssp. congdonii) Moderate Yes
Chorro Creek bog thistle (Cirsium fontinale var. obispoense) Moderate Yes
large-flowered leptosiphon (Leptosiphon grandifloras) Moderate Yes
adobe sanicle (Sanicula maritima) Moderate Yes
saline clover (Trifolium hydrophilum) Moderate Yes
Source: Appendix B
Environmental Checklist
Biological Resources
Initial Study – Mitigated Negative Declaration 27
Animal Species
The CNDDB review identified five invertebrate species, two fish species, five amphibian species, two
reptile species, 20 bird species, and eight mammal species with documented occurrences within a
five-mile radius of the treatment well site. Of these animal species, 16 have a low potential to occur,
six have a moderate potential to occur, and two have a high potential to occur at the treatment well
site.
Table 4 provides an overview of the CNDDB results for species with moderate and high potential to
occur at the treatment well site.
Table 4 Animal Species Potential to Occur at The Treatment Well Site
Species Potential to Occur
Potentially Suitable Habitat Present at
Treatment Well Site
California red-legged frog (Rana draytonii) High Yes
loggerhead shrike (Lanius ludovicianus) High Yes
Crotch’s bumble bee (Bombus crotchii) Moderate Yes
burrowing owl (Athene cunicularia) Moderate Yes
ferruginous hawk (Buteo regalis) Moderate Yes
Merlin (Falco columbarius) Moderate Yes
pallid bat (Antrozous pallidus) Moderate Yes
American badger (Taxidea taxus) Moderate Yes
Source: Appendix B
Land Cover Types/Vegetation Communities
Rincon conducted a review of vegetation communities present at the site, which are shown in
Figure 5. A description of these vegetation communities is provided below.
DEVELOPED
Developed land cover consists of areas that have been previously developed or modified to the
extent that they no longer contain native soil and habitat conditions and no longer support most
vegetation. This land cover type may also contain areas that are sparsely vegetated, primarily with
non-native species. Within the treatment well site, these areas include buildings, paved areas and
roadways, and gravel or hardpacked dirt roadways. This land cover type occurs throughout the
treatment well site and is associated with commercial development west of U.S. 101, the City
corporation yard and the WRRF, and existing paved and unpaved roadways and trails.
Approximately 8.3 acres of this land cover type is present.
AGRICULTURE
Agriculture consists of areas associated with existing agricultural operations. Within the treatment
well site (the area proposed for a water distribution pipe and connection to the City’s existing water
distribution system), these areas consist of hoop houses and row crops associated with existing
agricultural operations. This land cover type occurs in the northwest portion of the treatment well
site, west of U.S. 101. Approximately 0.2 acre of this land cover type is present.
City of San Luis Obispo
Groundwater Contamination Characterization Project
28
Figure 5 Vegetation Communities and Land Cover Types
Environmental Checklist
Biological Resources
Initial Study – Mitigated Negative Declaration 29
ORNAMENTAL
Ornamental land cover includes areas with planted vegetation, such as windbreaks, privacy screens,
lawns, or other landscaped areas. Ornamental areas are located throughout the treatment well site
and are often found adjacent to developed areas, particularly along roads, trails, and the San Luis
Obispo treatment plant. Planted species within ornamental areas on-site include pepper tree
(Schinus molle), Monterey pine (Pinus radiata), coast live oak (Quercus agrifolia), olive (Olea
europea), Santa Cruz island ironwood (Lyonothamnus floribundus ssp. aspleniifolius), wattle (Acacia
sp.), glossy privet (Ligustrum lucidum), and toyon (Heteromeles arbutifolia). Approximately 4.7 acres
of this land cover type is present.
COYOTE BRUSH SCRUB
Coyote brush scrub (Baccharis pilularis Shrubland Alliance) is a native coastal scrub vegetation
community that occurs on coastal bluffs, terraces, stabilized dunes, stream sides, and other similar
areas and features variable soils with sandy or relatively heavy clay. Coyote brush (Baccharis
pilularis) is dominant to co-dominant in the shrub canopy, occupying at least 50 percent absolute
cover in the shrub canopy. This vegetation community is typically less than three meters tall, the
shrub canopy is variable, and the herbaceous layer is variable. This vegetation community is ranked
G5S5 and is not classified as a CDFW sensitive natural community (CDFW 2024a). Coyote brush
scrub is present in several small patches in the southeastern portion of the treatment well site.
These patches are associated with larger, undisturbed areas of coyote brush scrub immediately
south of the treatment well site. Within the treatment well site, coyote brush is the dominant
species in the shrub canopy, with non-native herbaceous species including slender oat, cheeseweed
mallow (Malva parviflora), and milk thistle (Silybum marianum) present in the herbaceous layer.
Less than 0.1 acre of this vegetation community is present.
FENNEL PATCHES
Fennel patches (Foeniculum vulgare, Herbaceous Semi-Natural Alliance) are a native vegetation
community found across all topography between 0 and 1,000 meters. Fennel (Foeniculum vulgare)
contributes at least 50 percent relative cover in the herbaceous layer, and the herbaceous layer is
open to continuous. This vegetation community is not considered a CDFW sensitive natural
community (CDFW 2024a). Fennel patches are present along the existing unpaved roadway that
runs parallel to U.S. 101 in the eastern portion of the treatment well site. Within the treatment well
site, fennel is the dominant species in the herbaceous layer, with non-native wild radish (Raphanus
sativus) and bristly ox-tongue (Helminthotheca echioides) also present at lower cover.
Approximately 0.1 acre of this vegetation community is present.
UPLAND MUSTARD FIELDS
Upland mustard fields (Brassica nigra, Herbaceous Semi-Natural Alliance) are an open to continuous
semi-naturalized non-native vegetation community that occurs within fallow fields, rangelands,
grasslands, roadsides, and disturbed coastal scrub habitats. The soils are variable and contain clay to
sandy loams. This vegetation community is dominated by non-native ruderal forbs (e.g., black
mustard, short podded mustard [Hirschfeldia incana], and tocalote [Centaurea melitensis]). This
vegetation community is not classified as a CDFW sensitive natural community (CDFW 2024a).
Upland mustard fields are present throughout the treatment well site and are typically associated
with developed areas subject to frequent human disturbance, including paved and unpaved
roadways and trails. Within the treatment well site, dominant species within this vegetation
City of San Luis Obispo
Groundwater Contamination Characterization Project
30
community include non-native black mustard, short-podded mustard, tocalote, and prickly lettuce.
Other non-native species present include slender oat, bristly ox-tongue, Bermuda grass (Cynodon
dactylon), poison hemlock (Conium maculatum), and castor bean (Ricinus communis).
Approximately 3.9 acres of this vegetation community is present.
WILD OATS GRASSLAND
Wild oats grassland (Avena spp., Semi-Natural Alliance) is an open-to-dense naturalized vegetation
community that is dominated or co-dominated by non-native, often invasive, annual grasses (e.g.,
wild oats [Avena spp.] and foxtail barley [Hordeum murinum]). This vegetation community is often
interspersed with native and non-native forbs. Emergent trees and shrubs may be present but at
low cover. This vegetation community is not classified as a CDFW sensitive natural community
(CDFW 2024a). Wild oats grassland is present throughout the eastern portion of the treatment well
site and typically occurs in open areas adjacent to existing paved and unpaved roadways. Within the
treatment well site, this vegetation community is subject to frequent human disturbance in the
form of routine mowing and vegetation maintenance. Dominant species in the herbaceous layer
include slender oat and foxtail barley, with non-native prickly lettuce, field bindweed, and bristly ox-
tongue also present. Several small patches of native grasses, including purple needlegrass (Stipa
pulchra) and creeping wildrye (Elymus triticoides), are also present within this vegetation
community on-site. Additionally, several emergent coast live oak trees are present within this
vegetation community on-site. Approximately 5.6 acres of this vegetation community is present.
Impact Analysis
a. Would the project have a substantial adverse effect, either directly or through habitat
modifications, on any species identified as a candidate, sensitive, or special status species in
local or regional plans, policies, or regulations, or by the California Department of Fish and
Wildlife or U.S. Fish and Wildlife Service?
Plant Species
Each of the monitoring well locations outside of the treatment well site would be developed on
locations that are paved and feature existing infrastructure, and thus do not present the potential
for encountering sensitive plant species. The CNDDB and CNPS review identified five plant species
with a moderate potential to occur and four plant species with a high potential to occur at the
treatment well site. Based on the results of the Botanical Memorandum (Appendix B), no federal-
listed, state-listed, or other special-status plant species were observed at the treatment well site
during the botanical surveys. Therefore, no special-status plant species are present at the treatment
well site, and the project would have no impact on special-status plant species.
Animal Species
Each of the monitoring well locations outside of the treatment well site would be developed on
locations that are paved and feature existing infrastructure, and thus would not affect animal
species or their habitats. As summarized in Table 4, the CNDDB review identified six animal species
with a moderate potential to occur and two animal species with a high potential to occur at the
treatment well site. While no federal-listed, state-listed, or other special-status animal species were
observed at the treatment well site during field visits conducted in April, June, and July 2024, the
treatment well site does contain suitable habitat for these species. In addition to these species, the
project site contains suitable nesting habitat for nesting bird species. Due to the presence of
Environmental Checklist
Biological Resources
Initial Study – Mitigated Negative Declaration 31
suitable habitat at the treatment well site, project construction could result in the direct disturbance
of these special-status species (i.e., injury or mortality) if individuals are present in the work area
during construction. Furthermore, destruction or abandonment of native bird nests would violate
the California Fish and Game Code and Migratory Bird Treaty Act. These regulations make it
unlawful to take, possess, or destroy birds of prey and migratory birds, and their nests and eggs.
Therefore, potential direct impacts to special-status animal species are potentially significant.
Construction would also have the potential to result in indirect impacts to special-status species
through the potential introduction of sediment or pollutants to San Luis Obispo Creek. As detailed in
Section 7, Geology and Soils, the City’s construction contractor would be required to obtain
coverage under the General Permit for Storm Water Discharges Associated with Construction and
Land Disturbance Activities, Order No. 2022-0057-DWQ, NPDES No. CAS000002 (Construction
Stormwater General Permit), and would also be required to comply with the City’s standard BMPs
for erosion and sedimentation control (as required by the City’s adopted Standard Specifications
and Engineering Standards) which would ensure that best management practices (BMP) are
implemented which would minimize erosion and stormwater pollution. With adherence to the
Construction Stormwater General Permit and mandatory City Standards, the project would not
introduce substantial erosion or other pollutants into San Luis Obispo Creek and would not result in
substantial indirect impacts on the riparian habitat on the treatment well site or within San Luis
Obispo Creek. Regarding indirect impacts to nesting birds, in general, avian species can typically
avoid direct impacts from construction activity. However, construction activity around any active
nests could result in nest abandonment because of noise, vibrations, or human activity. Accordingly,
project construction could indirectly impact nesting birds, and this impact would be potentially
significant.
Mitigation Measures
BIO-1 Worker Environmental Awareness Program
Prior to initiation of construction activities at the treatment well site, all personnel associated with
project construction shall attend a Worker Environmental Awareness Program (WEAP) training,
conducted by a qualified biologist, to aid workers in recognizing special-status species and nesting
birds that may occur within the project site. The specifics of this program shall include identification
of special-status species with potential to occur, a description of their regulatory status and habitat
requirements, general ecological characteristics of any other sensitive resources, and a review of
the limits of construction and measures required to avoid and/or reduce impacts to biological
resources within the project site. A fact sheet conveying this information shall also be prepared for
distribution to the construction contractor. All employees shall sign a form provided by the biologist
indicating they have attended the WEAP training and understand the information presented to
them. The construction foreman shall ensure crew members are aware of project boundaries and
adhere to the mitigation measures designed to avoid or minimize effects to listed species, nesting
birds, and other special-status species.
BIO-2 Pre-Construction Survey for Special-Status Wildlife Species
A qualified biologist shall conduct a pre-construction survey of the treatment well site and adjacent
habitat no more than two weeks prior to the start of construction at the treatment well site. The
biologist shall document the presence or absence of any special-status wildlife species with
potential to occur within the treatment well site plus a 50-foot buffer. If special-status species are
observed onsite during the pre-construction surveys, they shall be allowed time to leave or be
City of San Luis Obispo
Groundwater Contamination Characterization Project
32
relocated prior to the initiation of construction activities. If special-status species are present during
construction activities, they shall be handled in accordance with Mitigation Measure BIO-3.
BIO-3 Biological Monitoring and Special-Status Species Relocation
A qualified biologist shall be onsite at the treatment well site during all vegetation removal, initial
ground disturbing activities, and/or during any construction activities that may impact sensitive
biological resources. If the biologist discovers special-status animal species on the project site, the
biologist shall have the authority to temporarily halt or redirect work to avoid potential impacts. If
avoidance is not feasible, the biologist shall be responsible for relocating wildlife species out of the
treatment well site in accordance with the requirements of applicable regulatory agencies, such as
CDFW or the United States Fish and Wildlife Service. Special-status wildlife shall not be handled
without prior permission from the necessary regulatory agencies. Species-specific monitoring
requirements may be superseded or added to by resource agency permits and/or incidental take
authorizations. Following the relocation of wildlife, the biologist shall submit a report to the City
confirming the methodology and results of relocating the wildlife.
BIO-4 Nesting Bird Surveys
A preconstruction nesting bird survey shall be conducted by a qualified biologist no more than 14
days prior to initiation of project construction activities. The survey shall be conducted within the
treatment well site and include a 50-foot buffer for passerines and a 500-foot buffer for raptors. The
survey shall be conducted by a biologist familiar with the identification of avian species known to
occur in the region and shall focus on trees, vegetated areas, and other potential nesting within the
vicinity of the treatment well site. If active nests are identified in the survey, an appropriate
avoidance buffer (typically 50 feet for passerine species and 500 feet for raptors) shall be
determined and demarcated by the biologist with high visibility material located within or adjacent
to the treatment well site. All project personnel shall be notified as to the existence of the buffer
zones and to avoid entering buffer zones during the nesting season. No project construction
activities shall occur within the buffer until the biologist has confirmed that breeding/nesting is
complete, and the young have fledged the nest. Encroachment into the buffer shall occur only at the
discretion of the qualified biologist.
Significance After Mitigation
Implementation of Mitigation Measures BIO-1 through BIO-4 would require worker environmental
awareness training, pre-construction surveys for special-status species and nesting birds, biological
monitoring and avoidance of special-status species and nesting birds, and, if necessary, relocation of
special-status species. With implementation of Mitigation Measures BIO-1 through BIO-4, direct and
indirect impacts to special-status species would be reduced to a less than significant level.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
b. Would the project have a substantial adverse effect on any riparian habitat or other sensitive
natural community identified in local or regional plans, policies, or regulations, or by the
California Department of Fish and Wildlife or U.S. Fish and Wildlife Service?
Each of the monitoring well locations outside of the treatment well site would be developed on
locations that are paved and feature existing infrastructure, and thus do not present the potential to
affect riparian habitat or sensitive natural communities. As described in the environmental setting
and shown in Figure 5, there are five vegetation communities at the treatment well site. None of
Environmental Checklist
Biological Resources
Initial Study – Mitigated Negative Declaration 33
these vegetation communities are identified as sensitive natural communities. San Luis Obispo
Creek and its associated riparian habitat are located adjacent to the treatment well site; however,
the project would not directly impact this riparian habitat. As described in Section 10, Hydrology and
Water Quality, adherence to the Construction Stormwater General Permit and the City’s mandatory
Standard Specifications and Engineering Standards would ensure appropriate BMPs are
implemented to minimize erosion and stormwater pollution, ensuring construction at the treatment
well site would not indirectly affect the riparian habitat of San Luis Obispo Creek through the
introduction of stormwater pollutants. Therefore, the project result in less than significant direct
and indirect impacts to riparian habitats or other sensitive natural communities.
LESS-THAN-SIGNIFICANT IMPACT
c. Would the project have a substantial adverse effect on state or federally protected wetlands
(including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling,
hydrological interruption, or other means?
Each of the monitoring well locations outside of the treatment well site would be developed on
locations that are paved and feature existing infrastructure, and thus do not present the potential to
affect wetlands. Based on a review of the National Wetlands Inventory, no wetlands are located on
the treatment well site or any of the monitoring well locations, but wetland habitat does exist
within San Luis Obispo Creek (United States Fish and Wildlife Service 2024). As described in
Threshold 4(b), construction would occur in accordance with the requirements of the Construction
Stormwater General Permit and the City’s mandatory Standard Specifications and Engineering
Standards, which would minimize the potential for erosion to fill or otherwise adversely affect San
Luis Obispo Creek. With regulatory adherence, the project would have a less than significant impact
related to wetland habitat.
LESS-THAN-SIGNIFICANT IMPACT
d. Would the project interfere substantially with the movement of any native resident or
migratory fish or wildlife species or with established native resident or migratory wildlife
corridors, or impede the use of native wildlife nursery sites?
Each of the monitoring well locations outside of the treatment well site would be developed on
locations that are paved and feature existing infrastructure, and thus do not present substantial
habitat connectivity. Based on a review of the CDFW Biogeographic Information and Observation
System, the treatment well site is not located in an area of substantial habitat connectivity (CDFW
2024b). The treatment well site is adjacent to commercial, residential, public facilities uses, and U.S.
101, and as such does not provide effective migration corridors for terrestrial species. San Luis
Obispo Creek is adjacent to the treatment well site; however, as described in Threshold 4(b),
regulatory compliance would minimize potential indirect impacts to San Luis Obispo Creek which,
subsequently, would minimize potential impacts to aquatic habitat utilizing San Luis Obispo Creek
for movement or nursery sites. Therefore, the project would have a less than significant impact
related to wildlife movement.
LESS-THAN-SIGNIFICANT IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
34
e. Would the project conflict with any local policies or ordinances protecting biological resources,
such as a tree preservation policy or ordinance?
The project would not interfere with the long-term natural function of the treatment well site’s
open space, consistent with the City’s policies to protect natural communities and avoid habitat
disturbance pursuant to the Conservation and Open Space Element of the General Plan (City of San
Luis Obispo 2014b). The monitoring well locations are all located on City property or within City
easement. The project would remove seven trees to install the access road and utility infrastructure.
Tree removal would occur consistent with the requirements of Chapter 12.24 of the City’s Municipal
Code, including compensatory tree planting (minimum 1:1 ratio). There is adequate area within the
City-owned parcel proposed for the treatment well site to accommodate the compensatory
plantings. All proximate trees proposed to remain would be avoided and preserved pursuant to the
City’s mandatory Standard Specifications and Engineering Standards for tree protection. The project
would not conflict with any local policies or ordinances protecting biological resources; therefore,
impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
f. Would the project conflict with the provisions of an adopted Habitat Conservation Plan, Natural
Community Conservation Plan, or other approved local, regional, or state habitat conservation
plan?
The project site is not located in any applicable adopted Habitat Conservation Plan, Natural
Community Conservation Plan, or other approved local, regional, or state habitat conservation plan
(City of San Luis Obispo 2006). Therefore, no impact would occur.
NO IMPACT
Environmental Checklist
Cultural Resources
Initial Study – Mitigated Negative Declaration 35
5 Cultural Resources
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Cause a substantial adverse change in the
significance of a historical resource
pursuant to §15064.5? □ □ ■ □
b. Cause a substantial adverse change in the
significance of an archaeological resource
pursuant to §15064.5? □ ■ □ □
c. Disturb any human remains, including
those interred outside of formal
cemeteries? □ ■ □ □
Rincon prepared a Cultural Resources Technical Report (CRTR) dated May 2024 which includes a
California Historical Resources Information System (CHRIS) records search through the Central Coast
Information Center (CCIC); a Native American Heritage Commission (NAHC) Sacred Lands File (SLF)
search; background research including in-depth review, archival, academic, and ethnographic
information; a review of a feasibility study that summarizes historical data and background studies
to understand the current PCE plume; a cultural resources pedestrian survey of the project site; an
analysis of the sensitivity of the project site to contain cultural resources; as well as management
recommendations. The setting and impact analysis provided are summarized based on the results of
the CRTR.5
Environmental Setting
On April 29, 2024, CCIC staff at the Santa Barbara Museum of Natural History conducted a CHRIS
records search to identify previously recorded cultural resources within the project site (treatment
well site and 12 monitoring well locations) and a 0.5-mile radius surrounding it. The CHRIS records
search identified 177 previous cultural resource studies within the 0.5-mile records search area, 29
of which address portions of the project site. The records search identified 256 previously recorded
cultural resources within the 0.5-mile records search radius. Of these, three are mapped as within
the project site: two historic buildings and/or structures and one historic period Chinese American
Cemetery. Of the remaining 253 previously recorded cultural resources, 25 are prehistoric and/or
historic period archaeological sites, four are prehistoric isolated cultural materials, and 224 are built
environment resources.
5 The report contains sensitive and confidential information concerning archaeological sites and is therefore held confidential not for
public distribution. Archaeological site locations are exempt from the California Public Records Act, as specified in Government Code
6254.10, and from the Freedom of Information Act (Exemption 3), under the legal authority of both the National Historic Preservation Act
(PL 102-574, Section 304[a]) and the Archaeological Resources Protection Act (PL 96-95, Section 9[a]).
City of San Luis Obispo
Groundwater Contamination Characterization Project
36
Impact Analysis
a. Would the project cause a substantial adverse change in the significance of a historical resource
pursuant to §15064.5?
The CHRIS records search identified two previously recorded cultural resources within the treatment
well site and one resource overlapping MW-02 and MW-03: two historic buildings and/or structures
and one historic period Chinese American Cemetery. One of the resources identified within the
treatment well site is documented as the San Luis Obispo WRRF and is mapped in CCIC records as
overlapping approximately 60 percent of the eastern portion of the treatment well site; however,
these areas are undeveloped and/or are developed with the Bob Jones Trail used for recreational
purposes and no buildings or structures associated with the facility were identified within the
project site. The other resource mapped within the treatment well site, Dalidio Ranch, is mapped in
CCIC records as overlapping approximately 5 percent of the northwestern portion of the treatment
well site; however, this portion of the treatment well site is undeveloped. Only minor utility
installations associated with the project would occur in this location and would not alter any existing
structures. Considering the absence of Dalidio Ranch structures and that the project would not
affect existing WRRF structures, the project would not affect historical resources associated with
Dalidio Ranch or the WRRF. According to the CRTR, the Chinese American Cemetery is mapped in
CCIC records as overlapping two monitoring well locations; however, the CRTR states review of
historical aerials and archival research suggests that it is possible that the resource is mapped
further south than what is captured in CCIC records, west and outside of the monitoring well
locations. Furthermore, there are no structures on at the monitoring well sites that suggest the
presence of a cemetery as the treatment well site is primarily undeveloped aside from the Bob
Jones Trail. Due to the lack of historic structures indicating the presence of a cemetery, the project
would not cause a substantial change in the significance of the cemetery. Therefore, the project
would not result in the substantial adverse change in the significance of a historical resource
pursuant to CEQA Guidelines Section 15064.5. Impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
b. Would the project cause a substantial adverse change in the significance of an archaeological
resource pursuant to §15064.5?
The NAHC SLF search returned a positive result; no informal outreach was conducted as part of the
CRTR.6 Refer to Section 18, Tribal Cultural Resources for a summary of formal tribal consultation
conducted for the project. The cultural resources pedestrian survey performed as part of the CRTR
focused on areas with exposed ground surfaces, which was limited to the treatment well site and
location of MW-09. The pedestrian field survey did not identify any cultural materials. Given the
developed nature of monitoring well locations MW-01 through MW-08 and MW-10 through MW-
12, and the method of construction activities proposed (i.e., drilling), there is limited potential to
encounter archaeological resources at these sites. As discussed above, historical aerials and archival
research suggests that it is possible that the Chinese American Cemetery resource is mapped further
south than what is captured in CCIC records, west and outside of the monitoring well location. The
alternative location believed to be the true location of resource of the Chinese American Cemetery
is a developed area outside of the treatment well site and monitoring well locations. Although the
treatment well site has been previously disturbed, the treatment well site is nevertheless
6 SLF search results do not provide details on cultural resources and are based on the township, range, and section information for a
project site rather than a precise location; therefore, the exact location and nature of the cultural resource is unknown.
Environmental Checklist
Cultural Resources
Initial Study – Mitigated Negative Declaration 37
considered sensitive for archaeological resources, consistent with the City’s Archaeological Resource
Preservation Program Guidelines and Conservation and Open Space Element. If project related
construction activities were to interfere with subsurface archaeological resources, this would be a
potentially significant impact.
Mitigation Measures
CUL-1 Workers Environmental Awareness Program Training
All construction personnel and monitors who are not trained archaeologists shall be briefed
regarding unanticipated discoveries prior to the start of construction activities. A basic presentation
shall be prepared and presented by a qualified archaeologist to inform all personnel working on the
project about the archaeological sensitivity of the area. The purpose of the WEAP training is to
provide specific details on the kinds of archaeological materials that may be identified during
construction of the project and explain the importance of and legal basis for the protection of
significant archaeological resources. Each worker shall also learn the proper procedures to follow in
the event that archaeological resources or human remains are uncovered during ground-disturbing
activities. These procedures include work curtailment or redirection, and the immediate contact of
the on-call archaeologist and if appropriate, Native American representative. The necessity of
training attendance shall be stated on all construction plans and the City of San Luis Obispo shall
maintain records demonstrating construction worker WEAP participation.
CUL-2 Archaeological and Native American Monitoring
Prior to any ground disturbing activities, the project proponent shall retain an archaeologist meeting
the Secretary of the Interior’s Qualifications Standards (NPS 1983) (Qualified Archaeologist) to
oversee the implementation of this measure.
Prior to any ground disturbing activities, the archaeologist shall provide a Cultural Resources
Mitigation and Monitoring Plan (CRMMP) for review and approval by the City of San Luis Obispo.
The CRMMP should include, but not be limited to, the following:
a. A list of personnel involved in the monitoring activities;
b. Description of Native American involvement;
c. Description of how the monitoring shall occur;
d. Description of location and frequency of monitoring (e.g., full time, part time, spot
checking);
e. Description of what resources may be encountered;
f. Description of circumstances that would result in the halting of work at the project site;
g. Description of procedures for halting work on the site and notification procedures;
h. Description of monitoring reporting procedures; and
i. Provide specific, detailed protocols for what to do in the event of the discovery of human
remains.
The Qualified Archaeologist shall provide conditional monitoring as well as on call response in the
case of an inadvertent discovery of archaeological resources. Given the developed nature of
monitoring well locations MW-01 through MW-08 and MW-10 through MW-12, and the method of
construction activities proposed (i.e., drilling), monitoring at these locations should be limited to
spot-checking and periodic examination of soils through selective sampling of soils brought to the
City of San Luis Obispo
Groundwater Contamination Characterization Project
38
surface as a result of the drilling activities. All construction-related ground disturbances, including
clearing/grubbing and drilling, within the treatment well site, west and east of U.S. 101) and west of
San Luis Obispo Creek be monitored by an archaeologist and a Native American representative. In
general, archaeological, and Native American monitoring shall be limited to initial ground
disturbance, which is defined as construction-related earthmoving of sediments from their native
place of deposition and does not include any secondary movement of sediment that might be
required for the project. The Qualified Archaeologist may adjust monitoring efforts as needed
(increase, decrease, or discontinue monitoring frequency) based on the observed potential for
construction activities to encounter archaeological deposits. The Qualified Archaeologist shall be
responsible for maintaining daily monitoring logs.
Throughout the course of project construction activities, if a discovery is made by construction
personnel and a monitor is not present, the protocols and procedures outlined in the Mitigation
Measure CUL-3, Unanticipated Discovery of Archaeological Resources, shall be followed. Following
the completion of construction, the Qualified Archaeologist shall prepare an archaeological
monitoring report for submittal to the City and the CCIC with the results of the archaeological
monitoring program.
CUL-3 Unanticipated Discovery of Archaeological Resources
In the event that archaeological remains are encountered during construction, City staff shall be
notified and all work within 50 feet of the find shall be halted until the find is evaluated by the
Qualified Archaeologist or other designated archaeologist working under the direction of the
Qualified Archaeologist and appropriate mitigation, if necessary, is implemented. If archaeological
remains are identified, the resource shall be evaluated for significance under City Archaeological
Resource Preservation Program Guidelines, and further treatment measures, including but not
limited to avoidance consistent with City General Plan Policies, Phase 2 Subsurface Archaeological
Resource Evaluation, or Phase 3 Archaeological Data Recovery Excavation may be required. Work
within 50 feet of the find shall not resume until authorization is received from the City. This measure
shall be included on all construction plans.
Significance After Mitigation
Implementation of Mitigation Measures CUL-1, CUL-2, and CUL-3 would ensure construction
personnel are informed of subsurface conditions and procedures are followed, such as halt of
construction work, retaining a qualified archaeological and native American monitor, and if
necessary, resource recovery. Adherence to Mitigation Measures CUL-1 through CUL-3 would
reduce the project’s impact on archaeological resources to a less than significant level.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
c. Would the project disturb any human remains, including those interred outside of formal
cemeteries?
Known prehistoric and historic period burials within or outside of formal cemeteries were identified
within a 0.5-mile of the 22-acre site and within areas of proposed monitoring wells as a result of the
CHRIS records search, literature review, and background research. According to the CRTC, a “Burial
Sensitivity Area” overlaps with one of the monitoring well locations. As a result, due to the
prehistoric and historical presence of Native Americans within the project area, including
documented burials within the 0.5-mile records search area, the project’s proximity to Mission San
Environmental Checklist
Cultural Resources
Initial Study – Mitigated Negative Declaration 39
Luis Obispo, and the Chinese American cemetery identified within CCIC records, there is a potential
to encounter previously unknown or yet identified human remains during project construction
activities.
In the event that human remains are inadvertently encountered during ground disturbing activities,
they would be treated consistent with state and local regulations including California Health and
Safety Code Section 7050.5, California Public Resources Code Section 5097.98, and the California
Code of Regulations Section 15064.5(e). In accordance with these regulations, if human remains are
found, the County Coroner must immediately notified of the discovery. No further disturbance
would occur until the County Coroner has made a determination of origin and disposition pursuant
to Public Resources Code Section 5097.98. If the County Coroner determines that the remains are,
or believed to be Native American origin, the County Coroner is required to notify the NAHC, who in
turn notifies those persons believed to be the most likely descendant (MLD). The MLD has 48 hours
from being granted site access to make recommendations for the disposition of the remains. If the
MLD does not make recommendations within 48 hours, the City would reinter the remains in an
area of the property secure from subsequent disturbance. Compliance with California Health and
Safety Code Section 7050.5, California Public Resources Code Section 5097.98, and the California
Code of Regulations Section 15064.5(e) would ensure the project would have a less than significant
impact related to the disturbance of human remains.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
City of San Luis Obispo
Groundwater Contamination Characterization Project
40
This page intentionally left blank.
Environmental Checklist
Energy
Initial Study – Mitigated Negative Declaration 41
6 Energy
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Result in a potentially significant
environmental impact due to wasteful,
inefficient, or unnecessary consumption
of energy resources, during project
construction or operation? □ □ ■ □
b. Conflict with or obstruct a state or local
plan for renewable energy or energy
efficiency? □ □ ■ □
Environmental Setting
Energy consumption is directly related to environmental quality in that the consumption of
nonrenewable energy resources releases criteria air pollutant and greenhouse gas (GHG) emissions
into the atmosphere. Energy use during construction work would be in the form of fuel
consumption (e.g., gasoline and diesel fuel) to operate construction equipment. The City’s
Conservation and Open Space Element and Climate Action Plan contain goals and policies primarily
related to reducing operational energy, including introduction of solar power, implementation of
energy conservation features in buildings, and implementation of carbon-sequestration measures
(City of San Luis Obispo 2014b; City of San Luis Obispo 2020a).
The environmental impacts of air pollutant and GHG emissions associated with the project’s energy
consumption are discussed in detail in Section 3, Air Quality, and Section 8, Greenhouse Gas
Emissions.
Impact Analysis
a. Would the project result in a potentially significant environmental impact due to wasteful,
inefficient, or unnecessary consumption of energy resources, during project construction or
operation?
Energy use during construction would be temporary for the duration of project construction activity.
Construction contractors would be required to comply with the provisions of California Code of
Regulations Title 13 Sections 2449 and 2485, which prohibit off-road diesel vehicles and diesel-
fueled commercial motor vehicles, respectively, from idling for more than five minutes and would
minimize unnecessary fuel consumption. Construction equipment would be subject to the United
States Environmental Protection Agency (USEPA) Construction Equipment Fuel Efficiency Standard
which would also minimize inefficient, wasteful, or unnecessary fuel consumption. Construction
contractors would be required to utilize fuel-efficient equipment consistent with state regulations
and would comply with state measures to ensure that inefficient, wasteful, or unnecessary
consumption of energy does not occur. Operation of the proposed project would require minimal
City of San Luis Obispo
Groundwater Contamination Characterization Project
42
energy in the form of electricity to power monitoring and treatment systems in addition to gasoline
use for vehicle trips to the well sites. This minimal energy use would not be wasteful, inefficient, or
unnecessary as it would be required to ensure proper function of the monitoring and treatment
wells to clean-up and prevent PCE contamination. With adherence to applicable regulations related
to energy efficiency, the proposed project’s impact related to energy use would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
b. Would the project conflict with or obstruct a state or local plan for renewable energy or energy
efficiency?
State regulations for energy conservation, such as the California Green Building Standards Code and
California Energy Code, target energy efficiency in the development or renovation of buildings and
would be inapplicable to the proposed project. In addition, the City’s energy-related goals and
policies within the Conservation and Open Space Element and Climate Action Plan have limited
applicability to the project as they focus primarily on energy conservation in buildings, solar design,
achieving carbon-free electricity, and carbon sequestration (City of San Luis Obispo 2014b; City of
San Luis Obispo 2020a). As the proposed buildings are limited to housing treatment equipment and
infrastructure, no State or local plans for renewable energy or energy efficiency would apply to the
proposed project. Therefore, impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Geology and Soils
Initial Study – Mitigated Negative Declaration 43
7 Geology and Soils
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Directly or indirectly cause potential
substantial adverse effects, including the
risk of loss, injury, or death involving:
1. Rupture of a known earthquake
fault, as delineated on the most
recent Alquist-Priolo Earthquake
Fault Zoning Map issued by the
State Geologist for the area or
based on other substantial evidence
of a known fault? □ □ ■ □
2. Strong seismic ground shaking? □ □ ■ □
3. Seismic-related ground failure,
including liquefaction? □ □ ■ □
4. Landslides? □ □ ■ □
b. Result in substantial soil erosion or the
loss of topsoil? □ □ ■ □
c. Be located on a geologic unit or soil that
is unstable, or that would become
unstable as a result of the project, and
potentially result in on- or off-site
landslide, lateral spreading, subsidence,
liquefaction, or collapse? □ □ ■ □
d. Be located on expansive soil, as defined
in Table 18-1-B of the Uniform Building
Code (1994), creating substantial direct
or indirect risks to life or property? □ □ ■ □
e. Have soils incapable of adequately
supporting the use of septic tanks or
alternative wastewater disposal systems
where sewers are not available for the
disposal of wastewater? □ □ □ ■
f. Directly or indirectly destroy a unique
paleontological resource or site or unique
geologic feature? □ ■ □ □
City of San Luis Obispo
Groundwater Contamination Characterization Project
44
Environmental Setting
The project site is within the southern Coast Range geomorphic province. The Coast Range province
is comprised of sub-parallel northwest-southeast trending faults, folds, and mountain ranges (City of
San Luis Obispo 2014a). According to the California Geological Survey the project site is not within
an Alquist-Priolo Fault Zone or overlay an active earthquake fault, the closest active fault to the
treatment well site is the Los Osos Fault Zone, located approximately one mile northwest (California
Geological Survey 2021). The Safety Element of the City’s General Plan recognizes the treatment
well site as an area having high liquefaction potential (City of San Luis Obispo 2014c). The treatment
well site is not within a landslide hazard zone (City of San Luis Obispo 2014c). Soils underlying the
treatment well site are primarily Salinas silty clay loam soil with zero to two percent slopes (United
States Department of Agriculture [USDA] 2024).
Impact Analysis
a.1. Would the project directly or indirectly cause potential substantial adverse effects, including the
risk of loss, injury, or death involving rupture of a known earthquake fault, as delineated on the
most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the
area or based on other substantial evidence of a known fault?
a.2. Would the project directly or indirectly cause potential substantial adverse effects, including the
risk of loss, injury, or death involving strong seismic ground shaking?
a.3. Would the project directly or indirectly cause potential substantial adverse effects, including the
risk of loss, injury, or death involving seismic-related ground failure, including liquefaction?
a.4. Would the project directly or indirectly cause potential substantial adverse effects, including the
risk of loss, injury, or death involving landslides?
c. Would the project be located on a geologic unit or soil that is unstable, or that would become
unstable as a result of the project, and potentially result in on- or off-site landslide, lateral
spreading, subsidence, liquefaction, or collapse?
d. Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform
Building Code (1994), creating substantial direct or indirect risks to life or property?
Individual well installation activities would include drilling to a maximum of 200 feet and would not
create conditions that would exacerbate unstable seismic conditions or stresses in the Earth’s crust.
Although the well locations are located near seismically active areas such as the Los Osos Fault
Zone, the project does not include development of occupiable buildings or infrastructure, thereby
exposing persons to geologic or soil related hazards, including ground shaking, fault rupture, lateral
spreading, subsidence, soil expansivity, landside, liquefaction or collapse. While there is a potential
for disturbance of the proposed water and wastewater distribution lines during a major seismic
event, the project would be designed to minimize the potential hazard and the City would
implement standard emergency protocols to minimize any related potential hazards due to pipe
displacement. Therefore, potential impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Geology and Soils
Initial Study – Mitigated Negative Declaration 45
b. Would the project result in substantial soil erosion or the loss of topsoil?
Each monitoring well would consist of one 2-inch or 4-inch diameter well. Due to the minimal
ground disturbance required for drilling and installation of a 2-inch or 4-inch diameter well, there is
no potential for monitoring well drilling to result in substantial erosion or siltation. As the overall
footprint of construction activities, including work at the treatment well site, would exceed one
acre, the project would be required to comply with the Construction Stormwater General Permit,
adopted by the SWRCB. This State requirement was developed to ensure that stormwater is
managed, and that erosion is controlled on construction sites. The Construction Stormwater General
Permit requires preparation and implementation of a Storm Water Pollution Prevention Plan
(SWPPP), which requires implementation of BMPs to control stormwater run-on and runoff from
construction work sites. The project would also be required to comply with the City’s standard BMPs
for erosion and sedimentation control (as required by the City’s adopted Standard Specifications
and Engineering Standards). BMPs may include, but would not be limited to, physical barriers to
reduce erosion and sedimentation, construction of sedimentation basins, limitations on work
periods during storm events, use of infiltration swales, protection of stockpiled materials, and a
variety of other measures to be identified by a qualified SWPPP developer that would substantially
reduce erosion from occurring during construction. With adherence to the Construction Stormwater
General Permit and the City’s mandatory Engineering Standards and Specifications, the project
would have a less than significant impact related to soil erosion.
LESS-THAN-SIGNIFICANT IMPACT
e. Would the project have soils incapable of adequately supporting the use of septic tanks or
alternative wastewater disposal systems where sewers are not available for the disposal of
wastewater?
The project would not include or require the use of septic tanks or alternative wastewater disposal
systems. On-site portable restroom facilities would be provided by the construction contractor for
workers operating at the site. No impact would occur.
NO IMPACT
f. Would the project directly or indirectly destroy a unique paleontological resource or site or
unique geologic feature?
Paleontological resources, or fossils, are the evidence of once-living organisms preserved in the rock
record. Such resources include both the fossilized remains of ancient plants and animals and the
traces of such remains. Paleontological resources are not found in “soil” but are rather found in the
geologic deposits or bedrock that underlies the soil layer. Typically, fossils are greater than 5,000
years old (i.e., older than middle Holocene in age) and preserved in sedimentary rocks. Although
rare, fossils can also be preserved in volcanic rocks or low-grade metamorphic rocks under certain
conditions (Society of Vertebrate Paleontology [SVP] 2010). Fossils often occur in an unpredictable
distribution within some sedimentary units.
Ground disturbing activities associated with the monitoring wells include drilling a 10-inch diameter
hole to install the wells. Only soil cuttings would be derived from the drilling; no underlying
geological units would be excavated. Soil cuttings do not produce geological materials with the
potential to discover or identify fossils. Accordingly, paleontological monitoring of monitoring well
installation could not result in quantitative or qualitative evaluations of potential paleontological
resources. As defined by SVP (2010), a fossil’s significance is tied directly to its scientific value; as
City of San Luis Obispo
Groundwater Contamination Characterization Project
46
such, fossils that would not be exposed during project activity or reasonably could be anticipated to
be exposed as a result of future human or natural events lack the access to scientific inquiry
necessary to be found as significant under CEQA. Therefore, because no known paleontological
resources would be impacted and any undiscovered resources would not otherwise be
encountered, ground disturbing activities at the monitoring wells would have a less than significant
impact on paleontological resources.
Ground disturbing activities at the treatment well site would involve drilling as well as grading to
install utility infrastructure and gravel access roads. According to mapping by Jennings (1958), the
treatment well site is underlain by Quaternary-aged alluvium (Jennings 1958). Similar to the
discussion of monitoring well drilling, drilling treatment well TW-4 would have a less than significant
impact on paleontological resources. Other ground disturbing activities at the treatment well site
are not anticipated to reach depths where older, potentially more sensitive sediments could be
encountered. However, the possibility remains that unanticipated paleontological resources could
be discovered during ground-disturbing activities at the treatment well site. Therefore, this impact
would be potentially significant.
Mitigation Measure
GEO-1 Unanticipated Discovery of Paleontological Resources
In the event of a fossil discovery by construction personnel at the treatment well site, the
construction contractor shall halt all construction activities within the 50 feet of the fossil, and a
Qualified Professional Paleontologist shall be retained to evaluate the find prior to resuming
construction activity. If it is determined the fossil(s) is (are) scientifically significant, the Qualified
Professional Paleontologist shall complete the following conditions to mitigate impacts to significant
fossil resources:
Fossil Salvage. If fossils are discovered, the Qualified Professional Paleontologist shall have the
authority to halt or temporarily divert construction equipment within 50 feet of the find until
the Qualified Professional Paleontologist evaluate the discovery and determine if the fossil may
be considered significant. Bulk matrix sampling may be necessary to recover small invertebrates
or microvertebrates from within paleontologically sensitive deposits.
Fossil Preparation and Curation. Once salvaged, significant fossils shall be identified to the
lowest possible taxonomic level, prepared to a curation-ready condition, and curated in a
scientific institution with a permanent paleontological collection along with all pertinent field
notes, photos, data, and maps. Fossils of undetermined significance at the time of collection
may also warrant curation at the discretion of the Qualified Professional Paleontologist.
Final Paleontological Report. The Qualified Professional Paleontologist shall submit a report
describing the results of the paleontological monitoring efforts associated with the project. The
report shall include a summary of the field and laboratory methods, an overview of the project
geology and paleontology, a list of taxa recovered (if any), an analysis of fossils recovered (if
any) and their scientific significance, and recommendations. The report shall be submitted to
the City.
Environmental Checklist
Geology and Soils
Initial Study – Mitigated Negative Declaration 47
Significance After Mitigation
Mitigation Measure GEO-1 describes procedures that shall be followed in the event an
unanticipated paleontological resource is encountered during construction at the treatment well
site. With implementation of Mitigation Measure GEO-1, potential impacts to paleontological
resources would be reduced to a less than significant level.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
City of San Luis Obispo
Groundwater Contamination Characterization Project
48
This page intentionally left blank.
Environmental Checklist
Greenhouse Gas Emissions
Initial Study – Mitigated Negative Declaration 49
8 Greenhouse Gas Emissions
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Generate greenhouse gas emissions,
either directly or indirectly, that may
have a significant impact on the
environment? □ □ ■ □
b. Conflict with an applicable plan, policy, or
regulation adopted for the purpose of
reducing the emissions of greenhouse
gases? □ □ ■ □
Environmental Setting
The principal state GHG reduction plans and policies are Assembly Bill (AB) 32, the California Global
Warming Solutions Act of 2006, and the subsequent legislation, Senate Bill (SB) 32 and AB 1279. The
goal of SB 32 is to reduce GHG emissions to 40 percent below 1990 levels by 2030. In 2022, the
State passed AB 1279, which declares the State would achieve net-zero GHG emissions by 2045 and
would reduce GHG emissions by 85 percent below 1990 levels by 2045. To implement these
requirements, CARB has published the 2022 Scoping Plan, which focuses on outcomes needed to
achieve carbon neutrality by assessing paths for clean technology, energy deployment, natural and
working lands, and others, and is designed to meet the state’s long-term climate objectives and
support a range of economic, environmental, energy security, environmental justice, and public
health priorities (CARB 2022).
SLOAPCD has developed GHG thresholds of significance through 2045 in accordance with Assembly
Bill 1279 and the California Air Resource Board’s 2022 Scoping Plan, which set forth a goal of
reducing GHG emissions by 85 percent below 1990 levels no later than 2045 (SLOAPCD 2023).
Pursuant to SLOAPCD guidance, projects which result in less than 830 metric tons of carbon dioxide
equivalent 7 (MT CO2e) per year in 2026 would have a less than significant impact related to GHG
emissions.
In 2020, the City adopted a Climate Action Plan, which establishes 2030 GHG emissions targets and
a carbon neutrality target by 2035 (City of San Luis Obispo 2020a).
7 Carbon dioxide equivalent is a unit of measurement used to standardize the climate effects of various GHGs in terms of the amount of
carbon dioxide that would create the same amount of global warming.
City of San Luis Obispo
Groundwater Contamination Characterization Project
50
Impact Analysis
a. Would the project generate GHG emissions, either directly or indirectly, that may have a
significant impact on the environment?
Based on the results of the CalEEMod modeling (Appendix A), construction of all components of the
proposed project would generate approximately 842 MT CO2e. Amortized over a 30-year period,
construction of the project would generate approximately 28 MT CO2e per year. This level of GHG
emission does not exceed SLOAPCD’s annual threshold of 830 MT CO2e. Therefore, construction of
the proposed project would have a less than significant impact related to GHG emissions.
Operation of the project would generate a nominal amount of GHG emissions from electricity
consumption to operate the treatment wells and occasional vehicle trips to the monitoring and
treatment well sites for maintenance activities, which would not have the potential to exceed
SLOAPCD GHG emissions thresholds. Therefore, the proposed project would have a less than
significant impact related to GHG emissions.
LESS-THAN-SIGNIFICANT IMPACT
b. Would the project conflict with an applicable plan, policy, or regulation adopted for the purpose
of reducing the emissions of greenhouse gases?
The City adopted a Climate Action Plan in 2020 with a goal of carbon neutrality by 2035. Since the
release of the City’s Climate Action Plan, the State adopted AB 1279, which sets a goal of achieving
statewide carbon neutrality by 2045. Although the City’s Climate Action Plan was released prior to
the adoption of AB 1279, because the Climate Action Plan sets a carbon neutrality goal consistent
with statewide efforts to achieve carbon neutrality, the Climate Action Plan is consistent with the AB
1279 carbon neutrality targets. Therefore, for the purposes of this analysis, the City’s Climate Action
Plan is the applicable plan for the project. Appendix C of the City’s Climate Action Plan includes
thresholds and guidance for preparation of GHG emissions analyses for projects within the city. To
support progress toward the City’s carbon neutrality goal, projects in San Luis Obispo must
demonstrate consistency with the Climate Action Plan.
Table 5 summarizes the proposed project’s consistency with the City’s Climate Action Plan, based on
applicable GHG Emissions Compliance Checklist measures (City of San Luis Obispo 2020a). As
described therein, the proposed project would not conflict with the Climate Action Plan. Therefore,
this impact would be less than significant.
Environmental Checklist
Greenhouse Gas Emissions
Initial Study – Mitigated Negative Declaration 51
Table 5 Project Consistency with the Climate Action Plan
Climate Action Plan Measures Project Consistency
Pillar 4: Connected Community
6a. Is the estimated Project/Plan-generated Vehicle Miles
Traveled (VMT) within the City’s adopted thresholds, as
confirmed by the City’s Transportation Division?
Consistent. Trips associated with the proposed project
would not exceed the City’s 110 trip per day threshold of
significance. For more information, refer to Section 17,
Transportation.
Pillar 6: Natural Solutions
9. Does the Project/Plan comply with Municipal Code
requirements for trees?
Consistent. The project would remove seven trees to
install the access road and utility infrastructure. Tree
removal would occur consistent with the requirements of
Chapter 12.24 of the City’s Municipal Code, including
compensatory tree planting (minimum 1:1 ratio). There is
adequate area within the City-owned parcel proposed for
the treatment well site to accommodate the
compensatory plantings. All proximate trees proposed to
remain would be avoided and preserved pursuant to the
City’s mandatory Standard Specifications and Engineering
Standards for tree protection.
Source: City of San Luis Obispo 2020a
LESS-THAN-SIGNIFICANT IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
52
This page intentionally left blank.
Environmental Checklist
Hazards and Hazardous Materials
Initial Study – Mitigated Negative Declaration 53
9 Hazards and Hazardous Materials
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Create a significant hazard to the public
or the environment through the routine
transport, use, or disposal of hazardous
materials? □ □ ■ □
b. Create a significant hazard to the public
or the environment through reasonably
foreseeable upset and accident
conditions involving the release of
hazardous materials into the
environment? □ □ ■ □
c. Emit hazardous emissions or handle
hazardous or acutely hazardous
materials, substances, or waste within
0.25 mile of an existing or proposed
school? □ □ ■ □
d. Be located on a site that is included on a
list of hazardous material 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? □ □ ■ □
e. For a project located in 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 or
excessive noise for people residing or
working in the project area? □ □ ■ □
f. Impair implementation of or physically
interfere with an adopted emergency
response plan or emergency evacuation
plan? □ □ ■ □
g. Expose people or structures, either
directly or indirectly, to a significant risk
of loss, injury, or death involving wildland
fires? □ □ ■ □
City of San Luis Obispo
Groundwater Contamination Characterization Project
54
Environmental Setting
The following databases were reviewed in July 2024 for known hazardous material contamination at
the treatment well site:
The SWRCB Geotracker database
The California Department of Toxic Substances Control’s (DTSC) EnviroStor database
The Superfund Enterprise Management System (SEMS) database
The treatment well site does not appear on any hazardous material site list compiled pursuant to
Government Code Section 65962.5 (DTSC 2024; SWRCB 2024a; U.S. EPA 2024). The treatment well
site is located within the San Luis Obispo County Regional Airport Land Use Plan, inside Zone 6,
Traffic Pattern Zone (RS&H 2021). There are no schools within 0.25-mile of the treatment well site.
The monitoring wells are not located on a hazardous material site list compiled pursuant to
Government Code Section 65962.5 (DTSC 2024; SWRCB 2024a; U.S. EPA 2024). The closest
hazardous materials sites to the monitoring wells are located approximately 320 feet west of MW-
01, 280 feet west of MW-02, 300 feet west of MW-03, and 150 feet north of MW-05. The sites
located proximate to MW-01, MW-03, and MW-05 are identified as “Completed- Case Closed”
which means site investigation and remedial action has been completed, and the Central Coast
Regional Water Quality Control Board determined no further action was required (SWRCB 2024a).
The site 280 feet west of MW-02, the South Higuera Street and Pismo Street Pipeline, is case open
for verification monitoring, meaning that remediation has been completed and monitoring of the
site has continued to ensure no further action is required (SWRCB 2024b). MW-04, MW-05, MW-07,
MW-09, MW-10, MW-11, and MW-12 are located within the San Luis Obispo County Regional
Airport Land Use Plan, inside Zone 6, Traffic Pattern Zone (RS&H 2021). MW-08 is located
approximately 0.25-mile southeast of Pacific Beach High School.
Impact Analysis
a. Would the project create a significant hazard to the public or the environment through the
routine transport, use, or disposal of hazardous materials?
b. Would the project 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?
c. Would the project emit hazardous emissions or handle hazardous or acutely hazardous
materials, substances, or waste within 0.25 mile of an existing or proposed school?
The project would not involve the routine use or disposal of hazardous materials, as project
activities would only last the duration of the construction phase (approximately 120 working days),
and no permanent project features would involve the operational use or disposal of hazardous
materials. There are no schools within 0.25-mile of the treatment well site. MW-08 is located
approximately 0.25-mile southeast of Pacific Beach High School.
Construction equipment would require the use of diesel fuel, gasoline, motor oil, and other similar
materials. Wastes derived from well installation and well development activities would include soil
cuttings, decontamination water, and development water. Pursuant to Title 22 of the California
Code of Regulations, the construction contractor would be required to submit samples of drilling
spoils for analytical testing required for waste profiling. Based on the results of the analytical
Environmental Checklist
Hazards and Hazardous Materials
Initial Study – Mitigated Negative Declaration 55
testing, soil cuttings and water would be containerized in 55-gallon drums, temporarily stored on-
site or at an appropriate location, and profiled for disposal; derived wastes would be transported
off-site and disposed of at an appropriate disposal facility.
These materials would be properly handled and disposed of in accordance with applicable
regulations. Construction personnel would be required to have the necessary training and/or
certifications to operate equipment used during project activities, minimizing the risk of accidental
release of hazardous materials due to equipment failure. The project would not increase,
encourage, or otherwise facilitate the transportation of hazardous materials above existing
conditions. The amount of fuels and oil to power construction equipment would be typical of similar
projects and no long-term operational impacts related to the routine transport, handling, or
disposal of hazardous materials would result from the project. Therefore, the project would not
create a significant hazard to the public or environment through the routine transport, use, or
disposal of hazardous materials, through reasonably foreseeable upset and accident conditions
involving the release of hazardous materials, or through use of hazardous materials within 0.25-mile
of a school. These impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
d. Would the project be located on a site that is included on a list of hazardous material 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?
The treatment well site is not included on any lists of hazardous materials compiled pursuant to
Government Code Section 65962.5 (DTSC 2024; SWRCB 2024a; U.S. EPA 2024).
Therefore, the project would not create a significant hazard to the public or environment due to
being located on a hazardous materials site compiled pursuant to Government Code Section
65962.5. No impact would occur. The site 280 feet west of MW-02, the South Higuera Street and
Pismo Street Pipeline, is case open for verification monitoring, meaning that remediation has been
completed and monitoring of the site has continued to ensure no further action is required (SWRCB
2024b). Due to the nature of construction at MW-02, temporary drilling lasting approximately 120
days would not have the potential to create a significant hazard to the public. As described in
Thresholds 9 (a)(b)(c), the construction contractor would be required to submit samples of drilling
spoils for analytical testing required for waste profiling transported off-site and disposed of at an
appropriate disposal facility. Therefore, any potentially contaminated soil from the hazardous
materials site 280 feet west of MW-02 would be safely disposed. MW-02 would be operated
remotely and would not continuously introduce the public to significant hazards. Therefore, this
impact would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
e. 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 or excessive noise for people residing or working in the project area?
The closest airport to the project site is the San Luis Obispo County Regional Airport, approximately
1.5 miles southeast of the treatment well site. Although the treatment well site is located in the
Traffic Pattern Zone, the project includes the installation of subsurface monitoring wells associated
with the treatment of groundwater. The project does not include development of habitable
structures and, therefore, would not continuously expose workers to airport noise. Temporary
City of San Luis Obispo
Groundwater Contamination Characterization Project
56
project workers at the treatment well site would only be required during the length of the
construction period (approximately 120 working days) or routine operational maintenance. As such,
the project would not result in a safety hazard or excessive noise for working at the project site. This
impact would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
f. Would the project impair implementation of or physically interfere with an adopted emergency
response plan or emergency evacuation plan?
Construction at the treatment wells would not involve interference with roadways. Construction of
a majority of the monitoring wells would be located adjacent to and within existing roadways which
could pose temporary interference with roadways due to staging of construction equipment.
Pursuant to the City’s Specifications and Engineering Standards, the construction contractor would
be required to create a temporary traffic control plan that adheres to standards for emergency
access in order to allow construction staging areas into the street network (City of San Luis Obispo
2020b). The traffic control plan would address required equipment, barricading, flagmen, use of
pilot vehicles, signing, tapers, and other components required to maintain traffic circulation. The
traffic control plan is required to address how traffic would be routed, including traffic from cross
streets, alleys, and private driveways. The traffic control plan would be subject to the approval of
the City Engineer prior to the start of construction activities. With development and implementation
of the traffic control plan, the project would not interfere with traffic management such that it
would conflict with City emergency response or evacuation plans. The project would not conflict
with adopted emergency response plan or emergency evacuation plan. This impact would be less
than significant.
LESS-THAN-SIGNIFICANT IMPACT
g. Would the project expose people or structures, either directly or indirectly, to a significant risk
of loss, injury, or death involving wildland fires?
The project site is located within a Local Responsibility Area and are not within a Very High Fire
Hazard Severity Zone, as defined by the California Department of Forestry and Fire Protection (CAL
FIRE) (CAL FIRE 2024). California Public Resources Code Section 4442 mandates the use of spark
arrestors, which prevent the emission of flammable debris from exhaust on earth-moving and
portable construction equipment with internal combustion engines that are operating on any forest-
covered, brush-covered, or grass-covered land. California Public Resources Code Section 4428
requires construction contractors to maintain fire suppression equipment during the highest fire
danger period (April 1 to December 1) when operating on or near any forest-covered, brush-
covered, or grass-covered land. Pursuant to compliance with this existing regulation, the project
would not expose people or structures, directly or indirectly, to a significant risk of loss, injury, or
death involving wildland fires. This impact would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Hydrology and Water Quality
Initial Study – Mitigated Negative Declaration 57
10 Hydrology and Water Quality
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Violate any water quality standards or
waste discharge requirements or
otherwise substantially degrade surface
or ground water quality? □ □ ■ □
b. Substantially decrease groundwater
supplies or interfere substantially with
groundwater recharge such that the
project may impede sustainable
groundwater management of the basin? □ □ ■ □
c. Substantially alter the existing drainage
pattern of the site or area, including
through the alteration of the course of a
stream or river or through the addition of
impervious surfaces, in a manner which
would:
(i) Result in substantial erosion or
siltation on- or off-site; □ □ ■ □
(ii) Substantially increase the rate or
amount of surface runoff in a
manner which would result in
flooding on- or off-site; □ □ ■ □
(iii) Create or contribute runoff water
which would exceed the capacity of
existing or planned stormwater
drainage systems or provide
substantial additional sources of
polluted runoff; or □ □ ■ □
(iv) Impede or redirect flood flows? □ □ ■ □
d. In flood hazard, tsunami, or seiche zones,
risk release of pollutants due to project
inundation? □ □ □ ■
e. Conflict with or obstruct implementation
of a water quality control plan or
sustainable groundwater management
plan? □ □ ■ □
City of San Luis Obispo
Groundwater Contamination Characterization Project
58
Environmental Setting
The San Luis Obispo Creek watershed is an approximately 53,271-acre coastal basin in southern San
Luis Obispo County, which rises to an elevation of about 2,500 feet above sea level in the Santa
Lucia Range. San Luis Obispo Creek flows to the Pacific Ocean and has six major tributary basins:
Stenner Creek, Prefumo Creek, Laguna Lake, East Branch San Luis Obispo Creek, Davenport Creek,
and See Canyon. The creek flows through the City and empties into the Pacific Ocean just west of
Avila Beach.
The City of San Luis Obispo is not subject to inundation from tsunami or seiche (City of San Luis
Obispo 2014c). The treatment well site is not located in a Special Flood Hazard Area, but is located
in an “Other Area of Flood Hazard” identified with a 0.2 percent annual chance flood hazard; areas
of one percent annual chance flood with average depth less than one foot or with drainage areas of
less than one square mile (FEMA 2024).
In 2015, the state legislature approved the Sustainable Groundwater Management Act (SGMA).
SGMA requires governments and water agencies of high and medium priority basins to halt
overdraft and bring groundwater basins into balanced levels of pumping and recharge. Under
SGMA, these basins should reach sustainability within 20 years of implementing their sustainability
plans. The project is located within the San Luis Obispo Valley Groundwater Basin, which has been
designated by the California Department of Water Resources (DWR) as a high-priority basin (DWR
2022). The County and City formed Groundwater Sustainability Agencies (GSAs) within their
respective jurisdictions to ensure full compliance with SGMA throughout the entire San Luis Obispo
Valley Groundwater Basin. The City is the GSA with jurisdiction over the well locations (City of San
Luis Obispo Department of Public Works 2022).
The project was initiated to characterize a PCE plume within the San Luis Valley Subarea of the San
Luis Obispo Valley Groundwater Basin, DWR Bulletin 118 Basin No. 3-09 (Basin), in San Luis Obispo
County.
Impact Analysis
a. Would the project violate any water quality standards or waste discharge requirements or
otherwise substantially degrade surface or ground water quality?
As stormwater flows over a construction site, it can pick up sediment, debris, and chemicals and
transport them to receiving water bodies. Additionally, soil disturbance during project construction
would increase the potential for erosion and sedimentation. Construction of the monitoring wells
would require minimal construction activities limited to linear drilling at one location for each
monitoring well, precluding the possibility of erosion. Construction at the treatment well site would
involve excavation for utility installation in addition to surface work to construct foundations for the
buildings, GAC vessels, and storage tanks, and the gravel access roads. As described in Threshold
7(b), construction would be required to comply with the Construction Stormwater General Permit,
which mandates preparation and implementation of a SWPPP and associated BMPs to control
stormwater run-on and runoff from construction work sites. The project is also required to comply
with the City’s standard BMPs for erosion and sedimentation control (as required by the City’s
adopted Standard Specifications and Engineering Standards). BMPs may include, but would not be
limited to, physical barriers to reduce erosion and sedimentation, construction of sedimentation
basins, limitations on work periods during storm events, use of infiltration swales, protection of
stockpiled materials, and a variety of other measures to be identified by a qualified SWPPP
developer that would substantially reduce erosion from occurring during construction. At the
Environmental Checklist
Hydrology and Water Quality
Initial Study – Mitigated Negative Declaration 59
completion of construction, the project would not introduce stormwater pollutants. With adherence
to these regulations, project construction would have a less than significant impact related to
violating water quality standards or waste discharge requirements.
LESS-THAN-SIGNIFICANT IMPACT
b. Would the project substantially decrease groundwater supplies or interfere substantially with
groundwater recharge such that the project may impede sustainable groundwater
management of the basin?
The purpose of the project is to improve water quality, through clean-up of existing PCE
contamination within in the San Luis Valley Subarea of the San Luis Obispo Valley Groundwater
Basin, and to expand local water supply resiliency by reducing reliance on local surface water
supplies. Extraction of groundwater would occur in compliance with SGMA and the approved
Groundwater Sustainability Plan (GSP), and meters would be installed to ensure compliance,
consistent with the City’s requirements to monitor all new wells within the City. Impervious surfaces
would be limited to structural foundations and paving within the protected and fenced treatment
well sites (approximately 0.4 acre). The project is required to comply with City Standard
Specifications and Engineering Standards for post-construction stormwater compliance. Therefore,
based on compliance with existing standards and requirements, including on-going metering and
monitoring of the groundwater extractions, the project would not substantially decrease
groundwater supplies, or substantially interfere with groundwater recharge such that the project
would impede sustainable groundwater management of the basin. Therefore, impacts would be less
than significant.
LESS-THAN-SIGNIFICANT IMPACT
c.(i) Would the project substantially alter the existing drainage pattern of the site or area,
including through the alteration of the course of a stream or river or through the addition of
impervious surfaces, in a manner which would result in substantial erosion or siltation on- or
off-site?
c.(ii) Would the project substantially alter the existing drainage pattern of the site or area,
including through the alteration of the course of a stream or river or through the addition of
impervious surfaces, in a manner which would substantially increase the rate or amount of
surface runoff in a manner which would result in flooding on- or off-site?
c.(iii) Would the project substantially alter the existing drainage pattern of the site or area,
including through the alteration of the course of a stream or river or through the addition of
impervious surfaces, in a manner that would create or contribute runoff water which would
exceed the capacity of existing or planned stormwater drainage systems or provide
substantial additional sources of polluted runoff?
c.(iv) Would the project substantially alter the existing drainage pattern of the site or area,
including through the alteration of the course of a stream or river or through the addition of
impervious surfaces, in a manner which would impede or redirect flood flows?
Construction activities would be limited to linear drilling at one location for each monitoring well,
precluding the possibility for exposing soil to erosion or siltation, exacerbating flooding, contributing
excess runoff, or impeding or redirecting flood flows. The monitoring wells would not introduce new
impervious surfaces which have the potential to alter existing drainage patterns which could result
in flooding or increase run off. Once subsurface monitoring wells are installed, a flush-mounted
traffic rated steel well box will be installed over each well. The project would create approximately
City of San Luis Obispo
Groundwater Contamination Characterization Project
60
0.40 acre of impervious surfaces due to structural foundations and paving within the two treatment
well locations. The project is required to comply with City Standard Specifications and Engineering
Standards for post-construction stormwater compliance. New gravel access roads would be installed
at the TW-3 and TW-4 sites; however, these would not be paved roads and therefore would not
result in additional impervious surfaces. Therefore, the project would not significantly alter the
existing drainage pattern of the site or area. Potential impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
d. In flood ha9zard, tsunami, or seiche zones, would the project risk release of pollutants due to
project inundation?
The City of San Luis Obispo is not subject to inundation from tsunami or seiche and the treatment
well site is not located in a Special Flood Hazard Area. Facilities or construction activities that use or
store large quantities of hazardous materials could harm the environment if inundated by a flood
resulting from a storm event or dam failure. As discussed in Section 9, Hazards and Hazardous
Materials, the project would not involve the routine use or disposal of hazardous materials beyond
the construction period, as project activities would only last the duration of construction
(approximately 120 working days for TW-4 and 50 working days for monitoring wells), and no
permanent features would be constructed that would involve the use or disposal of hazardous
materials. Groundwater contaminated with PCE would be treated and discharged into backwash
tanks, and wastewater would be transported to the City’s sewer system, all within a contained
system. There are no operational components which have the potential to introduce new pollutants
to the project site or result in a change to the existing flood patterns. Since the project would not
risk pollutant release due to project inundation in a flood hazard area, there would be no impact.
NO IMPACT
e. Would the project conflict with or obstruct implementation of a water quality control plan or
sustainable groundwater management plan?
The Water Quality Control Plan for the Central Coast Basin, adopted by the Central Coast Regional
Water Quality Control Board, is the water quality control plan applicable to the project site. The
Basin Plan establishes implementation programs to achieve water quality objectives to protect
beneficial uses. As described in Threshold 10(a), construction of the would be conducted in
compliance with the Construction Stormwater General Permit and the City’s mandatory Standards
Specifications and Engineering Standards to minimize the potential for pollutants to degrade water
quality. Operation of the project would not introduce new stormwater pollutants. Therefore, the
project would not conflict with the water quality objectives within the Water Quality Control Plan
for the Central Coast Basin.
The San Luis Obispo Valley Basin Groundwater Sustainability Plan is the applicable sustainable
groundwater management plan to the project site. As described in Threshold 10(b), the purpose of
the project is to improve water quality, through clean-up and prevention of PCE contamination in
drinking water supply wells in the San Luis Valley Subarea of the San Luis Obispo Valley
Groundwater Basin, and to expand local water supply resiliency by reducing reliance on local surface
water supplies. Extraction of groundwater would occur in compliance with SGMA and the approved
GSP, and meters would be installed to ensure compliance, consistent with the City’s requirements
to monitor all new wells within the City. Therefore, the project would not conflict with or obstruct
implementation of the San Luis Obispo Valley Basin Groundwater Sustainability Plan.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Land Use and Planning
Initial Study – Mitigated Negative Declaration 61
11 Land Use and Planning
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Physically divide an established
community? □ □ □ ■
b. Cause a significant environmental impact
due to a conflict with any land use plan,
policy, or regulation adopted for the
purpose of avoiding or mitigating an
environmental effect? □ □ ■ □
Environmental Setting
The 22-acre treatment well site is located in the southern portion of the City along U.S. 101 between
Prado Road and Los Osos Valley Road, the monitoring wells are dispersed on City property or within
City easement or right-of-way. The southern portion of the treatment well site is zoned
Conservation/Open Space (C/OS-20) and has a land use designation of Open Space. The northern
portion is zoned Public Facility (PF) and Public Facility-Special Considerations (PF-S) with a land use
designation of Public. The treatment well site is surrounded by U.S. 101 and commercial
development to the north, the City Water Resource Recovery Facility (WRRF) to the north, San Luis
Obispo Creek and residential development to the north/south.
Monitoring wells would be dispersed on City property or within City easements within the following
zones: Conservation/Open Space (C/OS-20), Medium Density Residential (R-2), Low-Density
Residential Specific Plan Overlay (R-1-SP), Public Facility (PF), Service Commercial (C-S), Service
Commercial Mixed Use Overlay (C-S-MU), Service Commercial Planned Development Overlay (C-S-
PD), Retail Commercial (C-R), Retail Commercial Planned development Overlay (C-R-PD), and Tourist
Commercial (C-T). The monitoring wells are on land designated with the following land uses: Service
and Manufacturing, General Retail, Tourist Commercial, Public, Low Density Residential, Medium
Density Residential, and Open Space.
Impact Analysis
a. Would the project physically divide an established community?
Construction staging for treatment well installation would occur in an area measuring approximately
40 feet by 10 feet to account for the drill rig footprint. As discussed in the Project Description, a 100-
foot buffer is added to the 40 feet by 10 feet to account for the work zone to accommodate the
support and decontamination truck, as well as the work area for the crew. Treatment well
installation would occur in City maintained open space along U.S. 101. Staging for monitoring well
locations would be conducted to maintain local access for residents to the extent practicable in
compliance with temporary traffic control measures specified within the City’s Standard
Specifications & Engineering Standards (City of San Luis Obispo 2020b). All work would occur within
City of San Luis Obispo
Groundwater Contamination Characterization Project
62
City property or City easement or right-of-way and would be temporary, lasting approximately 120
days for TW-4 and 50 days for monitoring wells. The project would not involve changes in land uses
or the creation of highways or other large-scale development or infrastructure with the potential to
divide an established community. Therefore, no impact would occur.
NO IMPACT
b. Would the project cause a significant environmental impact due to a conflict with any land use
plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental
effect?
The project does not propose any land use designation or zoning changes. The purpose of the
project is to monitor water quality and monitor the effectiveness of extracting and treating
impacted groundwater via the installation of treatment wells in an area surrounded by existing
public facility uses, such as the City corporation yard and the WRRF. Monitoring wells would be
dispersed on City property or within City easement or right-of-way. The project would not conflict
with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an
environmental effect. The project incorporates identified standards and regulations in effect for the
protection of the environment.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Mineral Resources
Initial Study – Mitigated Negative Declaration 63
12 Mineral Resources
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Result in the loss of availability of a
known mineral resource that would be of
value to the region and the residents of
the state? □ □ □ ■
b. Result in the loss of availability of a
locally important mineral resource
recovery site delineated on a local
general plan, specific plan, or other land
use plan? □ □ □ ■
Environmental Setting
Pursuant to Policy 6.5.1 of the Conservation and Open Space Element of the City’s General Plan,
mineral extraction is prohibited within City limits (City of San Luis Obispo 2014b).
Impact Analysis
a. Would the project result in the loss of availability of a known mineral resource that would be of
value to the region and the residents of the state?
b. Would the project result in the loss of availability of a locally important mineral resource
recovery site delineated on a local general plan, specific plan, or other land use plan?
The well sites are located on land classified as a Mineral Resources Zone-3, a classification where
mineral resources of unknown significance exist (DOC 1989). The well sites are within an existing
urbanized area of the City and the Conservation and Open Space Element of the City’s General Plan
prohibits mineral extraction. As such, the project would not result in the loss of availability of a
known mineral resource or locally important mineral resource recovery site delineated on a local
general plan, specific plan, or other land use plan. Therefore, no impacts would occur.
NO IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
64
This page intentionally left blank.
Environmental Checklist
Noise
Initial Study – Mitigated Negative Declaration 65
13 Noise
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project result in:
a. Generation of a substantial temporary or
permanent increase in ambient noise
levels in the vicinity of the project in
excess of standards established in the
local general plan or noise ordinance, or
applicable standards of other agencies? □ ■ □ □
b. Generation of excessive groundborne
vibration or groundborne noise levels? □ □ ■ □
c. For a project located within the vicinity of
a private airstrip or 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? □ □ □ ■
Environmental Setting
Sound is a vibratory disturbance created by a moving or vibrating source, which is capable of being
detected by the hearing organs. Noise is defined as sound that is loud, unpleasant, unexpected, or
undesired and may therefore be classified as a more specific group of sounds. The effects of noise
on people can include general annoyance, interference with speech communication, sleep
disturbance, and, in the extreme, hearing impairment. Noise levels are commonly measured in
decibels (dB) using the A-weighted sound pressure level (dBA). The A-weighting scale is an
adjustment to the actual sound pressure levels so that they are consistent with the human hearing
response. Groundborne vibration of concern in environmental analysis consists of the oscillatory
waves that move from a source through the ground to adjacent buildings or structures and vibration
energy may propagate through the buildings or structures. The primary concern from vibration is
that it may cause structural damage.
The City Municipal Code Chapter 9.12 - Noise Control, mandates that operating tools or equipment
used for construction activities between weekday hours of 7:00 p.m. and 7:00 a.m. or any time on
Sundays or holidays is strictly prohibited, except for emergency works of public service utilities or by
exception issued by the City Community Development Department. The Municipal Code also states
that construction activities shall be conducted in such a manner, where technically and economically
feasible, that the maximum noise levels at affected properties shall not exceed 75 dBA at single-
family residences, 80 dBA at multi-family residences, and 85 dBA at mixed residential/commercial
uses. The Municipal Code prohibits operating any device that creates ground vibration above the
City of San Luis Obispo
Groundwater Contamination Characterization Project
66
vibration perception threshold of an individual at or beyond 150 feet from the source on a public
space or right-of-way.
Noise exposure for various types of land uses reflect the varying noise sensitivities associated with
those uses. Sensitive receptors typically include residences, schools, healthcare facilities, and other
live-in housing facilities such as prisons or dormitories. The closest sensitive receptors to the project
site include single-family residences located approximately 15 feet east of MW-10, a single-family
residence located approximately 45 feet north of MW-06, a single-family residence located
approximately 50 feet east of MW-01 and mobile homes located approximately 65 feet north of
MW-03.
Regarding human perception, vibration levels would begin to be perceptible at levels of 0.04 inches
per second peak particle velocity (in/sec ppv) for continuous events and 0.25 in/sec ppv for
transient events (Caltrans 2020).
Impact Analysis
a. Would the project result in generation of a substantial temporary or permanent increase in
ambient noise levels in the vicinity of the project in excess of standards established in the local
general plan or noise ordinance, or applicable standards of other agencies?
Noise from construction equipment, site disturbance, and other project activities may temporarily
and intermittently dominate the noise environment in the immediate vicinity of the wells. As stated
above, the closest sensitive receptors to the project site include single-family residences located
approximately 15 feet east of MW-10, a single-family residence located approximately 45 feet north
of MW-06, a single-family residence located approximately 50 feet east of MW-01 and mobile
homes located approximately 65 feet north of MW-03. The nearest sensitive receptors to the
treatment well site are single-family residences located approximately 245 feet east of the
treatment well site. The portion of the Bob Jones Trail within the treatment well site is a
recreational use which is not considered a sensitive receptor. Table 6 shows typical noise levels
produced by common construction equipment anticipated to be used during construction of the
proposed monitoring wells and treatment well.
Table 6 Typical Noise Levels for Construction Equipment
Equipment Typical Noise Level 50 Feet from Source, dBA
Backhoe 80
Concrete Pump 82
Crane, Mobile 83
Rock Drill 95
Source: Federal Transit Administration 2018
At 245 feet, use of the construction equipment shown in Table 6 would result in a maximum noise
level of approximately 71 dBA which would not exceed the 75 dBA threshold established in the City
Municipal Code (Appendix C). Therefore, construction at the treatment well site would have a less
than significant impact related to construction noise.
Construction activities would occur at each monitoring well for approximately four days; therefore,
the time which sensitive noise receptors near monitoring well locations would be exposed to
construction noise would be short-term. However, use of this construction equipment could exceed
Environmental Checklist
Noise
Initial Study – Mitigated Negative Declaration 67
75 dBA as far as 150 feet from each monitoring well site (Appendix C). Therefore, sensitive noise
receptors near monitoring well locations (primarily residential properties within 150 feet of MW-01,
MW-02, MW-03, MW-06, and MW-10) would be exposed to intermittent and temporary
construction noise levels that exceed Municipal Code standards for construction near single-family
residential properties. As such, there would be a potentially significant impact to residential
properties surrounding monitoring well locations from short-term construction noise.
The proposed project would not include any operational components that create substantial noise
or otherwise introduce any long-term operational noise sources in the city. Therefore, operation of
the proposed project would have a less than significant impact related to excessive noise.
Mitigation Measures
N-1 Noise Reducing Best Management Practices
During monitoring well installation at MW-01, MW-02, MW-03, MW-06, and MW-10, the following
construction noise best management practices shall be adhered to:
Stationary construction equipment that generates noise that exceeds 60 dBA shall be shielded
with the most modern noise control devices (i.e. mufflers, lagging, and/or motor enclosures).
Impact tools (e.g., drills) used for project construction shall be hydraulically or electrically
powered wherever possible to avoid noise associated with compressed-air exhaust from
pneumatically powered tools.
Where use of pneumatic tools is unavoidable, an exhaust muffler on the compressed-air
exhaust shall be used.
All construction equipment shall have the manufacturers’ recommended noise abatement
methods installed, such as mufflers, engine enclosures, and engine vibration insulators, intact
and operational.
All construction equipment shall undergo inspection at periodic intervals to ensure proper
maintenance and presence of noise control devices (e.g., mufflers, shrouding, etc.).
At least 21 days prior to the start of construction, notify off-site businesses and residents within
150 feet of construction of planned construction activities. The notification shall provide brief
description of the project, activities that would occur, hours of construction, the duration of
construction, and a phone number to the City Community Development Department for the
public to direct noise-related complaints.
N-2 City Approval and Personnel Briefing
Construction plans shall note construction hours, truck routes, and all construction noise best
management practices, and shall be reviewed and approved by the City Utilities Department prior
to advertisement of the construction request for bids. All construction workers shall be briefed at a
preconstruction meeting on construction hour limitations and how, why, and where best
management practices are to be implemented.
Significance After Mitigation
Mitigation Measures N-1 and N-2 require implementation of standards noise best management
practices, such as the use of electric or hydraulically powered impact tools, and requirements for
signs and briefing of construction employees regarding all noise control measures to be
implemented throughout the construction phase. The Municipal Code states, where technically and
City of San Luis Obispo
Groundwater Contamination Characterization Project
68
economically feasible, construction activities shall be conducted in such a manner that the
maximum noise levels at affected properties will not exceed listed thresholds. Mitigation
Measures N-1 and N-2 serve as mitigation that would lower temporary and intermittent noise levels
to the extent technically and economically feasible. Therefore, following implementation of
Mitigation Measures N-1 and N-2, the proposed project would be consistent with the Municipal
Code, and this impact would be reduced to a less than significant level.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
b. Would the project result in generation of excessive groundborne vibration or groundborne noise
levels?
Use of a rotary sonic drill or hollow-stem auger for drilling would generate temporary and
intermittent groundborne noise or groundborne vibration during construction. These construction
activities would be periodic and limited in duration. As stated above, the closest sensitive receptors
to the project site include single-family residences located near monitoring well sites, including a
single-family residence located approximately 15 feet east of MW-10, a single-family residence
located approximately 45 feet north of MW-06, a single-family residence located approximately 50
feet east of MW-01 and mobile homes located approximately 65 feet north of MW-03.
Vibration levels associated with monitoring well drilling would begin to be perceptible at levels of
0.04 in/sec ppv for continuous events and 0.25 in/sec ppv for transient events. Given the short
duration and infrequent nature of drilling at the monitoring wells occurring during daytime hours,
the 0.25 in/sec ppv threshold for transient events is utilized for this analysis. At 15 feet, drilling
could result in a vibration level of approximately 0.19 in/sec ppv which would not exceed the exceed
the 0.25 in/sec ppv for transient events (Appendix C). Given that the 15 feet represents the closest
distance between a proposed well (MW-10) and sensitive receptor, monitoring well drilling would
not generate substantial groundborne vibration or groundborne noise exceeding applicable human
annoyance thresholds.
During operation, the proposed project would not include any components which would generate
any significant groundborne vibration or noise. Therefore, this impact would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
c. For a project located within the vicinity of a private airstrip or 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?
All wells except for MW-01 and MW-02 would be located within two miles of San Luis Obispo
County Regional Airport. However, according to the Airport Land Use Plan for the airport, the well
sties would be located outside of the noise contours of the San Luis Obispo County Regional Airport
(RS&H 2021). Therefore, the project would not expose construction workers to excessive airport
noise. Furthermore, the project does not include development of habitable or occupiable structures
and therefore would not expose any occupants to excessive airport noise. No impact would occur.
NO IMPACT
Environmental Checklist
Population and Housing
Initial Study – Mitigated Negative Declaration 69
14 Population and Housing
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Induce substantial unplanned population
growth in an area, either directly (e.g., by
proposing new homes and businesses) or
indirectly (e.g., through extension of
roads or other infrastructure)? □ □ □ ■
b. Displace substantial numbers of existing
people or housing, necessitating the
construction of replacement housing
elsewhere? □ □ □ ■
Environmental Setting
As of January 1, 2024, San Luis Obispo County’s population was 278,469 with 262,597 households,
and the City’s population was 48,684 persons, with 47,293 households (California Department of
Finance [DOF] 2024).
Impact Analysis
a. Would the project induce substantial unplanned population growth in an area, either directly
(for example, by proposing new homes and businesses) or indirectly (for example, through
extension of roads or other infrastructure)?
b. Would the project displace substantial numbers of existing people or housing, necessitating the
construction of replacement housing elsewhere?
The project would not require the removal of housing and therefore would not displace people or
housing. The project would not result in the construction of habitable structures or
commercial/industrial uses and would not induce population growth. The project would utilize a
minor number of temporary construction personnel over the course of the approximate 120
working day period for TW-4 and 50 working days for monitoring wells. Construction equipment
would be staged within individual work zones on City property or within City easement, which
would not interfere with surrounding infrastructure. Once completed, the project would not involve
ongoing operational uses that would result in new employment opportunities. The project would
not induce substantial unplanned population growth in an area, either directly or indirectly, or
require the displacement of existing people or housing. No impact would occur.
NO IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
70
This page intentionally left blank.
Environmental Checklist
Public Services
Initial Study – Mitigated Negative Declaration 71
15 Public Services
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
a. Would the project result in substantial
adverse physical impacts associated with
the provision of new or physically altered
governmental facilities, or the need for
new or physically altered governmental
facilities, the construction of which could
cause significant environmental impacts,
in order to maintain acceptable service
ratios, response times or other
performance objectives for any of the
public services:
1 Fire protection? □ □ ■ □
2 Police protection? □ □ ■ □
3 Schools? □ □ □ ■
4 Parks? □ □ □ ■
5 Other public facilities? □ □ □ ■
Environmental Setting
The San Luis Obispo Fire Department (SLOFD) provides fire protection services for the City. The fire
stations nearest to the well sites are Station 1, located at 2160 Santa Barbara Avenue,
approximately 0.75-mile northeast of MW-1, and Station 4, located at 1395 Madonna Road, 2,000
feet northwest of MW-6. In 2023, SLOFD maintained an average travel time of five minutes and 53
seconds, with a total response time of eight minutes and 41 seconds (SLOFD 2023).
The San Luis Obispo Police Department (SLOPD) provides public safety services for the City. SLOPD’s
Operation Bureau provides 24-hours emergency and non-emergency response, traffic enforcement,
and neighborhood outreach (SLOPD 2024). The SLOPD operates out of one police station located at
1042 Walnut Street.
City of San Luis Obispo
Groundwater Contamination Characterization Project
72
Impact Analysis
a. Would the project result in substantial adverse physical impacts associated with the provision
of new or physically altered governmental facilities, or the need for new or physically altered
governmental facilities, the construction of which could cause significant environmental
impacts, in order to maintain acceptable service ratios, response times or other performance
objectives for any of the public services:
1 Fire protection?
2 Police protection?
The project would not induce population growth, either directly or indirectly, or include any actions
that would have the potential to increase demand for fire protection or police protection services
such that new or physically altered fire or police stations would be warranted. If necessary,
supporting fire or police protective services during temporary construction activities would be
provided by the City’s police or fire departments. The project would not result in substantial
physical impacts associated with the provision of new or physically altered governmental facilities,
the construction of which could cause significant environmental impacts, in order to maintain
acceptable service ratios, response times or other performance objectives for fire protection
services or police protection services. No significant impacts to public services would occur.
LESS-THAN-SIGNIFICANT IMPACT
a. Would the project result in substantial adverse physical impacts associated with the provision
of new or physically altered governmental facilities, or the need for new or physically altered
governmental facilities, the construction of which could cause significant environmental
impacts, in order to maintain acceptable service ratios, response times or other performance
objectives for any of the public services:
3 Schools?
4 Parks?
5 Other public facilities?
The project would not induce population growth, either directly or indirectly, or include any actions
that would have the potential to increase demand for schools, libraries or other public services such
that new or physically altered public facilities would be warranted. Project activities would be
temporary and contained within individual work zones on City property or within City easement or
right-of-way, precluding the possibility to interfere with the existing use of parks or recreational
facilities. The project would not result in substantial physical impacts associated with the provision
of new or physically altered governmental facilities, the construction of which could cause
significant environmental impacts, in order to maintain acceptable service ratios or other
performance objectives for schools, parks, or other public facilities. No impact would occur.
NO IMPACT
Environmental Checklist
Recreation
Initial Study – Mitigated Negative Declaration 73
16 Recreation
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
a. Would the project increase the use of
existing neighborhood and regional parks
or other recreational facilities such that
substantial physical deterioration of the
facility would occur or be accelerated? □ □ □ ■
b. Does the project include recreational
facilities or require the construction or
expansion of recreational facilities which
might have an adverse physical effect on
the environment? □ □ □ ■
Environmental Setting
The Park and Recreation Blueprint for the Future identifies 28 City parks and 15 recreational
facilities in the City, including a golf course, sports complex, stadium, swim center, community
center, skate park, senior center, and community gardens. Additionally, the City owns and manages
13 open spaces and recreational trails that cover approximately 4,050 acres (City of San Luis Obispo
2021).
Impact Analysis
a. Would the project increase the use of existing neighborhood and regional parks or other
recreational facilities such that substantial physical deterioration of the facility would occur or
be accelerated?
b. Does the project include recreational facilities or require the construction or expansion of
recreational facilities which might have an adverse physical effect on the environment?
The project would not induce population growth, either directly or indirectly, which would have the
potential to increase the demand for parks or other recreational facilities. Temporary construction
activities would be staged within individual work zones on City property or within City easement,
precluding the possibility to interfere with or prohibit the use of existing neighborhood or regional
parks or other recreational facilities such that other parks or recreational facilities would be utilized
more frequently, and substantial physical deterioration of the facility would occur or be accelerated.
The project does not include construction of recreational facilities and would not require the
construction or expansion of recreational facilities which might have an adverse physical effect on
the environment. Therefore, no impacts to recreation would occur.
NO IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
74
This page intentionally left blank.
Environmental Checklist
Transportation
Initial Study – Mitigated Negative Declaration 75
17 Transportation
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Conflict with a program, plan, ordinance
or policy addressing the circulation
system, including transit, roadway,
bicycle and pedestrian facilities? □ □ ■ □
b. Conflict or be inconsistent with CEQA
Guidelines section 15064.3, subdivision
(b)? □ □ ■ □
c. Substantially increase hazards due to a
geometric design feature (e.g., sharp
curves or dangerous intersections) or
incompatible use (e.g., farm equipment)? □ □ ■ □
d. Result in inadequate emergency access? □ □ ■ □
Environmental Setting
Regional access to the project site is available via U.S. 101. Monitoring wells are located throughout
the City of San Luis Obispo and are accessed via local roads. Local access to the treatment well site is
provided via Prado Road, Los Osos Valley Road, and Calle Joaquin. Bicycle facilities on these streets
include buffered lanes and protected bike lanes (City of San Luis Obispo 2024a). In addition, the
treatment well site includes a portion of the Bob Jones Trail which is a multi-use path available for
cyclists and pedestrians.
Impact Analysis
a. Would the project conflict with a program, plan, ordinance or policy addressing the circulation
system, including transit, roadway, bicycle and pedestrian facilities?
Trips associated with project activities would be limited to worker trips to and from the project site,
delivery trips for heavy equipment and construction tools, and trips to dispose of soil and other
construction debris. Construction-related vehicle trips would be temporary and would cease once
construction is complete. Construction contractors would be required to comply with the temporary
traffic control provisions set forth in the City’s Standard Specifications and Engineering Standards
(City of San Luis Obispo 2020b). This document provides guidelines for traffic control during
construction, including maintaining traffic, specifications for flagging, pavement delineation, among
other topics. In addition, a Traffic Control Plan, compliant with the provisions set forth in the
Caltrans Manual on Uniform Traffic Control Devices would be required to be approved by the City
Engineer or their designee prior to the start of construction activities. All traffic coordination on City
Streets and within the Bob Jones Bikepath undertaken by construction contractors would require
the City Engineer’s approval no fewer than three days prior to implementation of traffic
City of San Luis Obispo
Groundwater Contamination Characterization Project
76
coordination activities (City of San Luis Obispo 2020b). Compliance with these existing standards
and measures would ensure that project construction would not conflict with a program, plan,
ordinance or policy addressing the circulation system.
Operation of the project would result in minimal vehicle trips for occasional monitoring activities,
and these trips would not result in vehicle traffic which could conflict with a program, plan,
ordinance or policy addressing the circulation system. Therefore, this impact would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
b. Would the project conflict or be inconsistent with CEQA Guidelines section 15064.3,
subdivision (b)?
CEQA Guidelines Section 15064.3 describes specific considerations for evaluating a project’s
transportation impacts. Specifically, the guidelines state VMT exceeding an applicable threshold of
significance may indicate a significant impact. Pursuant to CEQA Guidelines Section 15064.3(b)(3), a
lead agency may include a qualitative analysis of project-related traffic. The City has adopted VMT
thresholds consistent with the thresholds and methodologies contained in the California Governor’s
Office of Land Use and Climate Innovation’s (formerly the Governor’s Office of Planning and
Research) Technical Advisory on Evaluating Transportation Impacts in CEQA (City of San Luis Obispo
2020c). As described therein, a project that is anticipated to generate less than 110 vehicle trips per
day may be assumed to cause a less than significant impact.
Construction of the proposed project would result in short-term, temporary vehicle trips to and
from the project site during the construction period. These temporary vehicle trips would not result
in long-term changes to VMT within San Luis Obispo; therefore, project construction VMT would not
conflict or be inconsistent with CEQA Guidelines Section 15064.3(b).
During operation, minimal maintenance trips would be required to monitor the wells and maintain
the extraction and treatment system; however, these trips would not result in an exceedance of 110
daily vehicle trips, and the project would not generate growth or create an increase in traffic such
that substantial increases in VMT could occur. Therefore, the project would not conflict or be
inconsistent with CEQA Guidelines Section 15064.3(b), and this impact would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
c. Would the project substantially increase hazards due to a geometric design feature (e.g., sharp
curves or dangerous intersections) or incompatible use (e.g., farm equipment)?
The proposed project would not alter or affect the city’s existing street network. Construction of
MW-01, MW-05, MW-07, MW-08, MW-10, and MW-12 may temporarily result in partial road
closures; however, construction contractors would be required to comply with temporary traffic
control provisions set forth in the City’s Standard Specifications and Engineering Standards,
including implementation of a traffic control plan to reduce temporary traffic hazards during
construction (City of San Luis Obispo 2020b). At the completion of construction activity, equipment
would be removed, and the monitoring wells would be located underground. The project site would
not have any new geometric design features or incompatible uses that would increase hazards for
vehicular and pedestrian traffic. Therefore, the proposed project would not substantially increase
Environmental Checklist
Transportation
Initial Study – Mitigated Negative Declaration 77
hazards due to a geometric design feature or incompatible uses. This impact would be less than
significant.
LESS-THAN-SIGNIFICANT IMPACT
d. Would the project result in inadequate emergency access?
Traffic impacts during project construction would be primarily associated with minor roadway and
multi-use pathway delays and temporary partial lane closures. However, any minor delays during
project construction would be temporary in nature and would not result in long-term inadequate
emergency access. To minimize potential impacts to emergency access during construction, the
project would be required to comply with the City’s Standard Specifications and Engineering
Standards and implement a traffic control plan that adheres to City standards for emergency access,
including prohibiting personal vehicles of construction workers from parking on the traveled way of
the construction zone and approval from the City’s Engineer or their designee for any traffic
restrictions (City of San Luis Obispo 2020b). Operation of the project would not impair emergency
access as wells would be located underground, and minimal operational vehicle trips would be
required. Therefore, the proposed project would have a less than significant impact related to
emergency access.
LESS-THAN-SIGNIFICANT IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
78
This page intentionally left blank.
Environmental Checklist
Tribal Cultural Resources
Initial Study – Mitigated Negative Declaration 79
18 Tribal Cultural Resources
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project cause a substantial adverse
change in the significance of a tribal cultural
resource, defined in a Public Resources Code
Section 21074 as either a site, feature, place,
or cultural landscape that is geographically
defined in terms of the size and scope of the
landscape, sacred place, or object with
cultural value to a California Native American
tribe, and that is:
a. Listed or eligible for listing in the
California Register of Historical
Resources, or in a local register of
historical resources as defined in Public
Resources Code Section 5020.1(k)? □ ■ □ □
b. A resource determined by the lead
agency, in its discretion and supported by
substantial evidence, to be significant
pursuant to criteria set forth in
subdivision (c) of Public Resources Code
Section 5024.1? In applying the criteria
set forth in subdivision (c) of Public
Resources Code Section 5024.1, the lead
agency shall consider the significance of
the resource to a California Native
American tribe. □ ■ □ □
Environmental Setting
California Assembly Bill 52 of 2014 (AB 52) expanded CEQA by defining a new resource category,
“tribal cultural resources.” AB 52 establishes that “a project with an effect that may cause a
substantial adverse change in the significance of a tribal cultural resource is a project that may have
a significant effect on the environment” (PRC Section 21084.2). It further states that the lead agency
shall establish measures to avoid impacts that would alter the significant characteristics of a tribal
cultural resource, when feasible (PRC Section 21084.3).
PRC Section 21074 (a)(1)(A-B) defines tribal cultural resources as “sites, features, places, cultural
landscapes, sacred places, and objects with cultural value to a California Native American tribe” and
are:
City of San Luis Obispo
Groundwater Contamination Characterization Project
80
1. Listed or eligible for listing in the CRHR, or in a local register of historical resources as defined in
PRC Section 5020.1(k), or
2. A resource determined by the lead agency, in its discretion and supported by substantial
evidence, to be significant pursuant to criteria set forth in PRC Section 5024.1(c). In applying
these criteria, the lead agency shall consider the significance of the resource to a California
Native American tribe.
The City sent notification letters to listed tribal contacts in the region on July 25, 2024, which
included the Santa Ynez Band of Mission Indians, the Barbareno/Ventureno Band of Mission Indians,
the Salinan Tribe of Monterey and San Luis Obispo County, the Tule River Indian TribeYak Tityu Tityu
– Northern Chumash Tribe, the Northern Chumash Tribal Council, the Torres Martinez Desert
Cahuilla Indians, the Chumash Council of Bakersfield, and the Coastal Band of the Chumash Nation.
Native American Tribes were notified on July 25, 2024 about the project consistent with City and
State regulations including, but not limited to, Assembly Bill 52. During the request for consultation
window, two responses were received. The Salinan Tribe of Monterey responded on August 30,
2024 requesting notification in the event of a cultural resource discovery during construction. The
Santa Ynez Band of Chumash Indians contacted the City on August 5, 2024 requesting a consultation
meeting to discuss the project. The City consulted with the Tribe on September 17, 2024 and shared
information regarding the project, the results of the cultural resources survey, and proposed
mitigation measures. The Tribe informed the City that they are in agreement with the mitigation
measures laid out in the public review Draft IS-MND for a workers environmental awareness
program training, archaeological monitoring, and protocol in the event of unanticipated discoveries.
Pursuant to PRC §21080.3.1 (b) the request for consultation window closed on August 26, 2024. No
other tribal agencies responded to the consultation request.
Impact Analysis
a. Would the project cause a substantial adverse change in the significance of a tribal cultural
resource as defined in Public Resources Code Section 21074 that is listed or eligible for listing in
the California Register of Historical Resources, or in a local register of historical resources as
defined in Public Resources Code Section 5020.1(k)?
b. Would the project cause a substantial adverse change in the significance of a tribal cultural
resource as defined in Public Resources Code 21074 that is a resource determined by the lead
agency, in its discretion and supported by substantial evidence, to be significant pursuant to
criteria set forth in subdivision (c) of Public Resources Code Section 5024.1?
During preparation of the Cultural Resources Assessment, Rincon contacted the NAHC on
December 17, 2021, requesting an SLF search for traditional cultural resources. The NAHC
responded on March 11, 2022, indicating the results of the SLF search was positive, meaning
traditional cultural resources are present within the SLF search area. The NAHC provided a
consultation list of 14 Native American groups within traditional lands or cultural places located
within the SLF search area.
SLF searches are conducted by using USGS quadrangle maps, each of which covers an approximately
50- to 70-square-mile area, and the NAHC does not provide the specific location of tribal heritage
resources. Consequently, a positive SLF search does not explicitly indicate the presence of tribal
cultural resources on the project site. However, based on the positive results of the SLF search, the
project site could have the potential to contain tribal cultural resources that could be eligible for
Environmental Checklist
Tribal Cultural Resources
Initial Study – Mitigated Negative Declaration 81
listing in the CRHR or local register, or considered to be a tribal cultural resource under CEQA. As
discussed in Section 5, Cultural Resources, the potential to encounter archaeological resources
during ground-disturbing activities exists. If encountered, previously undiscovered cultural
resources could potentially be considered eligible for listing in the CRHR or a local register or be
considered tribal cultural resources. As such, impacts to tribal cultural resources would be
potentially significant.
Mitigation Measures CR-1, CR-2, and CR-3 would implement a worker’s environmental awareness
program, standard procedures for the unanticipated discovery of cultural resources, require a
Native American representative to participate in the evaluation of unanticipated cultural resources
discovered during construction activities, and enforce procedures for Native American consultation
in the event human remains are discovered. Upon implementation of Mitigation Measures CR-1,
CR-2, and CR-3, the project would not cause a substantial adverse change in the significance of a
tribal cultural resource.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
City of San Luis Obispo
Groundwater Contamination Characterization Project
82
This page intentionally left blank.
Environmental Checklist
Utilities and Service Systems
Initial Study – Mitigated Negative Declaration 83
19 Utilities and Service Systems
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Would the project:
a. Require or result in the relocation or
construction of new or expanded water,
wastewater treatment or storm water
drainage, electric power, natural gas, or
telecommunications facilities, the
construction or relocation of which could
cause significant environmental effects? □ □ ■ □
b. Have sufficient water supplies available
to serve the project and reasonably
foreseeable future development during
normal, dry and multiple dry years? □ □ ■ □
c. Result in a determination by the
wastewater treatment provider which
serves or may serve the project that it
has adequate capacity to serve the
project’s projected demand in addition to
the provider’s existing commitments? □ □ ■ □
d. Generate solid waste in excess of State or
local standards, or in excess of the
capacity of local infrastructure, or
otherwise impair the attainment of solid
waste reduction goals? □ □ ■ □
e. Comply with federal, state, and local
management and reduction statutes and
regulations related to solid waste? □ □ ■ □
Environmental Setting
The City’s Utilities Department provides water and wastewater services to the City. Wastewater
generated within the City, California Polytechnic State University, and the County airport is treated
at the Water Resource Recovery Facility (WRRF). The WRRF treats approximately 4.5 million gallons
of wastewater daily (City of San Luis Obispo 2024c). The City’s Utilities Department is also
responsible for administering an agreement with the San Luis Garbage Company for waste
collection services. Most solid waste collected in the City is disposed of at the Cold Canyon Landfill
(City of San Luis Obispo 2014a). Cold Canyon Landfill has a maximum permitted capacity of 1,650
tons per day (California Department of Resources, Recycling, and Recovery [CalRecycle] 2020). As of
2020, the landfill’s estimated remaining capacity was 13,000,000 cubic yards with an estimated
closure date of December 2040 (CalRecycle 2020). Electricity services in the City are provided by
City of San Luis Obispo
Groundwater Contamination Characterization Project
84
Pacific Gas & Electric Company and natural gas services are provided by the Southern California Gas
Company.
Impact Analysis
a. Would the project require or result in the relocation or construction of new or expanded water,
wastewater treatment or storm water drainage, electric power, natural gas, or
telecommunications facilities, the construction or relocation of which could cause significant
environmental effects?
b. Would the project have sufficient water supplies available to serve the project and reasonably
foreseeable future development during normal, dry and multiple dry years?
c. Would the project result in a determination by the wastewater treatment provider which serves
or may serve the project that it has adequate capacity to serve the project’s projected demand
in addition to the provider’s existing commitments?
As described under Section 3, Air Quality, construction activities would require minimum amounts
of water for dust suppression. Adequate water supplies would be available to meet the needs of the
project for dust suppression purposes. In accordance with Municipal Code Section 13.07.070(c),
potable City water would not be used for major construction activities, such as grading and dust
control, and would not be used to wash down sidewalks, driveways, or parking areas except to
alleviate immediate fire or sanitation hazards. Consequently, the project would not use the City’s
drinking water for dust suppression. No buildings or structures would be constructed that would
result in new long-term water demand. Minimal wastewater would be generated by construction
worker personnel during temporary construction activities (approximately 120 working days for the
TW-4 and 50 working days for the monitoring wells, including testing) which would be served by on-
site portable restroom facilities. The City’s WRRF and collection system has sufficient capacity to
accept the wastewater generated by the treatment process. Groundwater extraction would occur in
compliance with SGMA and the adopted GSP to ensure to adverse impacts occur to the
groundwater basin or flows within San Luis Obispo Creek.
Therefore, the project would have sufficient water supplies available, would not require or result in
relocation or construction of new or expanded water or stormwater facilities, and would not exceed
wastewater treatment demand beyond existing conditions.
As discussed in Section 6, Energy, the project would require minimal, temporary energy use
throughout construction, and construction equipment used would be typical of similar-sized
construction projects in the region. Project operation would not increase the demand for additional
electric power or natural gas as compared to existing conditions. Therefore, the project would not
require or result in additional electric power or natural gas facilities. Similarly, the project would not
require the need for additional telecommunications facilities.
Overall, the project would not require relocation or construction of new or expanded utilities
facilities, increase water demand, or result in inadequate wastewater treatment capacity. These
impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Utilities and Service Systems
Initial Study – Mitigated Negative Declaration 85
d. Would the project generate solid waste in excess of State or local standards, or in excess of the
capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction
goals?
e. Would the project comply with federal, state, and local management and reduction statutes
and regulations related to solid waste?
Project construction activities would generate construction waste; wastes derived from well
installation and well development activities would include soil cuttings, decontamination water, and
development water. The construction contractor would be required to submit samples of drilling
spoils for analytical testing required for waste profiling. Based on the results of the analytical
testing, soil cuttings and water would be containerized in 55-gallon drums, temporarily stored on-
site or at an appropriate location, and profiled for disposal; derived wastes would be transported
off-site and disposed of at an appropriate disposal facility.
For other temporary solid waste applicable to landfill (i.e. trash, green, sand, and/or non-recyclable
PCC), Cold Canyon Landfill has sufficient permitted capacity to accommodate the project’s
temporary solid waste disposal needs associated with construction activities. Pursuant to Assembly
Bill 939 and Municipal Code Chapter 8.04, recoverable materials generated during construction
would be separated and recycled to minimize construction and waste exportation from the site,
resulting in limited demand on the landfills within the County. Operation of the project would not
generate solid waste. Therefore, the project would not generate solid waste in excess of State or
local standards, or in the excess of capacity of local infrastructure, and the project would comply
with federal, state, and local management reduction statues and regulations related to solid waste.
These impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
City of San Luis Obispo
Groundwater Contamination Characterization Project
86
This page intentionally left blank.
Environmental Checklist
Wildfire
Initial Study – Mitigated Negative Declaration 87
20 Wildfire
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
If located in or near state responsibility areas
or lands classified as very high fire hazard
severity zones, would the project:
a. Substantially impair an adopted
emergency response plan or emergency
evacuation plan? □ □ ■ □
b. Due to slope, prevailing winds, and other
factors, exacerbate wildfire risks and
thereby expose project occupants to
pollutant concentrations from a wildfire
or the uncontrolled spread of a wildfire? □ □ ■ □
c. Require the installation or maintenance
of associated infrastructure (such as
roads, fuel breaks, emergency water
sources, power lines or other utilities)
that may exacerbate fire risk or that may
result in temporary or ongoing impacts
to the environment? □ □ ■ □
d. Expose people or structures to significant
risks, including downslopes or
downstream flooding or landslides, as a
result of runoff, post-fire slope instability,
or drainage changes? □ □ ■ □
Environmental Setting
The central coast of California is prone to wildfire due to a warm, dry climate and expansive
coverage of ignitable vegetation. However, the project site is not within a State Responsibility Area
or a Very High Fire Hazard Severity Zone as defined by CAL FIRE (CALFIRE 2024). The closest Fire
Hazard Severity Zone to the treatment well site is approximately one mile west, extending from
foothills of Mine Hill.
City of San Luis Obispo
Groundwater Contamination Characterization Project
88
Impact Analysis
a. If located in or near state responsibility areas or lands classified as very high fire hazard severity
zones, would the project substantially impair an adopted emergency response plan or
emergency evacuation plan?
b. If located in or near state responsibility areas or lands classified as very high fire hazard severity
zones, would the project, due to slope, prevailing winds, and other factors, exacerbate wildfire
risks and thereby expose project occupants to pollutant concentrations from a wildfire or the
uncontrolled spread of a wildfire?
c. If located in or near state responsibility areas or lands classified as very high fire hazard severity
zones, would the project require the installation or maintenance of associated infrastructure
(such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may
exacerbate fire risk or that may result in temporary or ongoing impacts to the environment?
d. If located in or near state responsibility areas or lands classified as very high fire hazard severity
zones, would the project expose people or structures to significant risks, including downslopes
or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or
drainage changes?
The project site is not within a State Responsibility Area or a Very High Fire Hazard Severity Zone
(CAL FIRE 2024). The project would involve the movement of construction equipment, hauling of
construction equipment, and transportation of construction personnel which could temporarily
increase traffic on roadways when accessing the well locations, which could possibly delay
emergency vehicles. However, any minor delays during project construction would be temporary in
nature and would not impair an adopted emergency response plan or emergency evacuation plan.
The project would be required to comply with the City’s Standard Specifications and Engineering
Standards and implement a traffic control plan that adheres to City standards for emergency access.
Therefore, the project would not substantially impair an adopted emergency response plan or
emergency evacuation plan.
Heavy duty equipment used during construction that may produce sparks that could ignite
vegetation would be limited through regulatory compliance. California Public Resources Code
Section 4442 mandates the use of spark arrestors, which prevent the emission of flammable debris
from exhaust on earth-moving and portable construction equipment with internal combustion
engines that are operating on any forest-covered, brush-covered, or grass-covered land. PRC Section
4428 requires construction contractors to maintain fire suppression equipment during the highest
fire danger period (April 1 to December 1) when operating on or near any forest-covered, brush-
covered, or grass-covered land. These regulations would minimize the risk of fire resulting from
project construction activities. No roads, fuel breaks, emergency water sources, or power lines
would be installed. In addition, the project would not result in additional housing and would not
accommodate occupants. Thus, the project would not expose persons to pollutant concentrations
from a wildfire, exacerbate fire risk due to installation or maintenance of associated infrastructure,
or expose people or structures to significant risks as a result of runoff, post-fire slope instability, or
drainage changes. These impacts would be less than significant.
LESS-THAN-SIGNIFICANT IMPACT
Environmental Checklist
Mandatory Findings of Significance
Initial Study – Mitigated Negative Declaration 89
21 Mandatory Findings of Significance
Potentially
Significant
Impact
Less than
Significant
with
Mitigation
Incorporated
Less-than -
Significant
Impact No Impact
Does the project:
a. Have the potential to substantially
degrade the quality of the environment,
substantially reduce the habitat of a fish
or wildlife species, cause a fish or wildlife
population to drop below self-sustaining
levels, threaten to eliminate a plant or
animal community, substantially reduce
the number or restrict the range of a rare
or endangered plant or animal or
eliminate important examples of the
major periods of California history or
prehistory? □ ■ □ □
b. Have impacts that are individually
limited, but cumulatively considerable?
(“Cumulatively considerable” means that
the incremental effects of a project are
considerable when viewed in connection
with the effects of past projects, the
effects of other current projects, and the
effects of probable future projects)? □ ■ □ □
c. Have environmental effects which will
cause substantial adverse effects on
human beings, either directly or
indirectly? □ ■ □ □
Impact Analysis
a. Does the project have the potential to substantially degrade the quality of the environment,
substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population
to drop below self-sustaining levels, threaten to eliminate a plant or animal community,
substantially reduce the number or restrict the range of a rare or endangered plant or animal or
eliminate important examples of the major periods of California history or prehistory?
The project is limited to activities that would occur at the treatment well site and monitoring well
sites; therefore, the project would not impact the total mapped habitat areas of the special-status
plant and animal species with potential to occur at these sites. The project does not include large-
scale activities which would pose a substantial threat to special-status species or their mapped
habitats. Due to the local scale of the project, the project would not substantially reduce the habitat
of a fish or wildlife species cause a fish or wildlife population to drop below self-sustaining levels,
City of San Luis Obispo
Groundwater Contamination Characterization Project
90
threaten to eliminate a plant or animal community, or substantially reduce the number or restrict
the range of a rare or endangered plant or animal. This impact would be less than significant.
The well sites do not contain important examples of the major periods of California history or
prehistory. Therefore, the project would not have a substantial effect on these resources. As
discussed in Section 5, Cultural Resources, Mitigation Measures CR-1, CR-2, CR-3, and CR-4 would
minimize potential effects on cultural and tribal cultural resources. Accordingly, the project would
not eliminate important examples of the major periods of California history or prehistory.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
b. Does the project have impacts that are individually limited, but cumulatively considerable?
(“Cumulatively considerable” means that the incremental effects of a project are considerable
when viewed in connection with the effects of past projects, the effects of other current
projects, and the effects of probable future projects)?
As described in Sections 1 through 20, with respect to all environmental issues, the project’s
potential impacts associated with project construction activities would be either less than significant
or reduced to a less than significant level with implementation of required mitigation. This is
because project construction would be temporary, and project operation would not result in
adverse effects on the environmental baseline conditions. Cumulatively considerable impacts could
occur if the construction of other projects occurs at the same time as the project and in the same
vicinity, such that the effects of similar impacts of multiple projects combine to expose a resource to
greater levels of impact than would occur under the project.
Certain resource areas (e.g., Geology and Soils, Hazards and Hazardous Materials) are by their
nature specific to a project location, such that impacts at one location do not add to impacts at
other locations.
Other resource areas inherently address cumulative impacts. As noted in Section 3, Air Quality, and
Section 8, Greenhouse Gas Emissions, the project would comply with SLOAPCD’s Clean Air Plan and
the City’s Climate Action Plan, along with other regulations that would reduce the project’s air
quality impacts and greenhouse gas emissions to less than significant levels. The Clean Air Plan
establishes thresholds, and the Climate Action Plan contains a consistency checklist, both of which
that are designed such that a project that demonstrates compliance with these items would not
have an individually or cumulatively significant impact. Consequently, the project would not
generate a cumulatively considerable impacts to air quality or greenhouse gas emissions.
Additionally, the project would have no impact on agriculture and forestry resources, land use,
mineral resources, population and housing, public services, or recreation, and therefore, would not
have the potential to contribute to cumulative impacts to these environmental issue areas. The
discussion of cumulative impacts is limited to the following issue areas:
Aesthetics. Projects within San Luis Obispo have the potential to result in cumulative changes to
the city’s visual environment by introducing development that blocks scenic views, is visually
inconsistent with its surroundings, or introduces substantial light and glare. However, these
projects would be subject to the City’s applicable regulations related to scenic quality, height
limitations, and minimum setback requirements established within the City’s General Plan and
Municipal Code. These projects would implement City lighting standards to shield lighting from
adjacent sites. With adherence to City regulations related to aesthetics, cumulative
development in the City of San Luis Obispo would have a less than significant impact related to
aesthetics.
Environmental Checklist
Mandatory Findings of Significance
Initial Study – Mitigated Negative Declaration 91
Biological Resources. Cumulative projects that may be developed within the city would be
subject to similar regulatory requirements as the project. These include, but are not limited to,
the federal Endangered Species Act, California Endangered Species Act, and Migratory Bird
Treaty Act. These regulations are designed to protect individual species and their habitats.
Cumulative projects would be required to abide by the provisions of these regulations and
subject to review from agencies including, but not limited to, CDFW and the United States Fish
and Wildlife Service, to ensure potential impacts to species or habitat are minimized. However,
existing regulatory requirements alone cannot guarantee species loss, habitat loss, or other
impact to biological resources due to cumulative development. The project has the potential to
impact special-status species and nesting birds during construction, but the project would
incorporate mitigation measures, including worker environmental awareness training, pre-
construction surveys, and biological monitoring and special status species relocation or
avoidance. With incorporation of these measures, the project would not contribute
considerably to cumulative impacts related to biological resources.
Cultural Resources. Projects within San Luis Obispo, particularly those in undeveloped areas,
may disturb archaeological resources during construction and other ground-disturbing activities.
Therefore, cumulative development has the potential to have a significant impact on cultural
resources. Project construction at the well sites could result in potential disturbance to
subsurface archaeological resources; however, implementation of Mitigation Measures CUL-1
through CUL-3, which require construction worker training on identifying archaeological
resources, monitoring during ground disturbance activities, and procedures for the
unanticipated discovery of archaeological resources. With incorporation of these measures, the
project would not contribute considerably to cumulative impacts related to cultural resources.
Energy. Cumulative projects in the city would use energy during construction and operation in
the form of gasoline, diesel, natural gas, and electricity. Cumulative development would be
required to comply with existing State regulations such as California Code of Regulations Title 13
Sections 2449 and 2485, the California Green Building Standards Code, and California Energy
Code, which are implemented, in part, to ensure development does not result in the wasteful,
inefficient, or unnecessary consumption of energy resources. With adherence to these
regulatory requirements, cumulative impacts related to energy would be less than significant.
Hydrology and Water Quality. The geographic area used to assess cumulative impacts to
surface water is the San Luis Obispo Creek watershed. The geographic area used to assess
cumulative impacts to groundwater is the San Luis Obispo Valley Groundwater Basin. A
cumulative impact could occur if projects discharge pollutants to the San Luis Obispo Creek
watershed and violate water quality standards, or if these projects would result in substantially
decreased groundwater supplies. Cumulative projects would be required to comply with
federal, state, and City water quality requirements, such as the Construction Stormwater
General Permit and City Standard Specifications and Engineering Standards (erosion and
sedimentation control, and water quality standards). Cumulative impacts to hydrology and
surface water quality would be minimized with adherence to these regulations. Therefore,
cumulative impacts to surface water would be less than significant. Cumulative development
could result in increased water demand from the San Luis Obispo Valley Groundwater Basin.
However, the basin is managed through the San Luis Obispo Valley Basin Groundwater
Sustainability Plan which would ensure cumulative development in San Luis Obispo does not
increase groundwater extraction beyond sustainable levels. As a result, cumulative
development would not receive groundwater in conflict with the sustainable management
City of San Luis Obispo
Groundwater Contamination Characterization Project
92
policies of the San Luis Obispo Valley Groundwater Basin. Cumulative impacts related to
sustainable groundwater management would be less than significant
Noise. Construction and operational noise and vibration are localized and rapidly attenuate.
Cumulative construction impacts could occur if cumulative development in San Luis Obispo is
located proximate to the treatment or monitoring wells such that overlapping construction
schedules or operational noise- or vibration-generating sources could result in increased noise
and vibration at the same sensitive receptors. The closest cumulative development to the
project site is expansion of the WRRF, currently under construction, located adjacent to the
treatment well stie to the northeast (City of San Luis Obispo 2024d). Due to the proximity to the
project site, there is potential that if construction of the project and the WRRF overlapped,
nearby sensitive receptors could potentially be exposed to substantial noise. Therefore,
cumulative impacts are potentially significant. At the treatment well site the project would not
exceed the City’s 75 dBA threshold for construction noise. Therefore, the project would not
contribute considerably to cumulative noise impacts.
Transportation. Cumulative development could result in a greater number of vehicle trips in San
Luis Obispo compared to existing conditions, increasing citywide VMT, which would be a
significant cumulative impact. The project would require temporary construction trips which
would not result in long-term changes to VMT in San Luis Obispo. Operation of the project
would require minimal maintenance trips which would not exceed 110 daily trips, and would
not result in substantial increases in citywide VMT. Therefore, the project would not contribute
considerably to cumulative transportation impacts.
Utilities and Service Systems. Cumulative development could result in increased water demand
in excess of existing supplies, wastewater generation and solid waste generation in excess of
existing facilities’ capacity, and increased electric and natural gas demand requiring substantial
infrastructure. As described in the City’s Urban Water Management Plan, the City anticipates
having adequate water to supply cumulative development through 2040 in normal, single dry
years, and multiple dry years (City of San Luis Obispo 2024e). Therefore, cumulative water
supply impacts would be less than significant. The WRRF treats approximately 4.5 million gallons
per day and has a capacity of 5.1 million gallons per day. However, expansion to the WRRF,
anticipated to be completed in late 2024, would increase treatment capacity to 5.4 million
gallons per day, which is planned to accommodate wastewater flows in the City under full
General Plan buildout. Therefore, cumulative wastewater impacts would be less than significant.
Cold Canyon Landfill has an estimated remaining capacity of 13,000,000 cubic yards with an
estimated closure date of December 2040. Therefore, adequate landfill capacity is available to
serve cumulative development and cumulative solid waste impacts would be less than
significant. Existing electric and natural gas infrastructure is present throughout San Luis Obispo,
and cumulative development is anticipated to only require minor connections to existing natural
gas and electric infrastructure. Therefore, cumulative impacts to electric and natural gas
infrastructure would be less than significant.
Wildfire. Cumulative development in San Luis Obispo could result in wildfire hazards that could
potentially expose residents and employees within San Luis Obispo to wildfire or pollutants
associated with wildfire smoke. Cumulative development would be required to adhere to
applicable regulations to minimize fire risk, including the California Fire Code, California Public
Resources Code Regulations, and San Luis Obispo Fire Department requirements. These
regulations would ensure cumulative development would minimize the potential for wildfire to
occur within SaSan Luis Obispo. Therefore, cumulative wildfire impacts would be less than
significant.
Environmental Checklist
Mandatory Findings of Significance
Initial Study – Mitigated Negative Declaration 93
Based on the analysis above, the project would not result in a cumulatively considerable
contribution to a significant cumulative impact.
LESS-THAN-SIGNIFICANT IMPACT
c. Does the project have environmental effects which will cause substantial adverse effects on
human beings, either directly or indirectly?
Adverse effects on human beings are typically associated with air quality, hazards and hazardous
materials, noise, and wildfire impacts. These impacts are addressed in Section 3, Air Quality, Section
8, Hazards and Hazardous Materials, and Section 12, Noise. As discussed in detail in these sections,
the project would not result in substantial adverse effects to humans due to exposure to air quality
criteria pollutants in excess of established regulatory thresholds set by SLOAPCD. The project would
not result in substantial impacts related to hazards and hazardous materials. With implementation
of Mitigation Measures N-1 and N-2, the project would minimize temporary and intermittent noise
levels during construction. Therefore, the project would not have environmental effects which
would cause substantial adverse effects on human beings and this impact would be less than
significant with mitigation incorporated.
LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED
City of San Luis Obispo
Groundwater Contamination Characterization Project
94
This page intentionally left blank.
References
Initial Study – Mitigated Negative Declaration 95
References
Bibliography
California Air Resources Control Board (CARB). 2014. California Air Basin Map.
https://www.arb.ca.gov/ei/maps/statemap/abmap.htm (accessed August 2024).
______. 2022. 2022 Scoping Plan. https://ww2.arb.ca.gov/sites/default/files/2022-12/2022-
sp_1.pdf (accessed August 2024).
California Department of Conservation (DOC). 1989. Aggregate Resources and Active Mines of All
Other Mineral Commodities San Luis Obispo-Santa Barbara P-C Region.
https://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=mlc
(accessed July 2024).
______. 2022. California Important Farmland Finder. https://maps.conservation.ca.gov/DLRP/CIFF/
(accessed July 2024).
California Department of Finance (DOF). 2024. Table 2: E-5 City/County Population and Housing
Estimates, 1/1/2022. Accessible at:
https://dof.ca.gov/Forecasting/Demographics/Estimates/e-5-population-and-housing-
estimates-for-cities-counties-and-the-state-2020-2024// (accessed July 2024).
California Department of Fish and Wildlife (CDFW). 2024a. California Natural Community List.
Available at: https://www.wildlife.ca.gov/Data/VegCAMP/Natural-Communities (accessed
May 2023).
California Department of Forestry and Fire Protection (CAL FIRE). 2024. FHSZ Viewer. https://calfire-
forestry.maps.arcgis.com/apps/mapviewer/index.html?layers=ac8ed44d76ed4988bceb07d
35d80f4cb (accessed July 2024).
California Department of Resources, Recycling, and Recovery (CalRecycle). 2020. SWIS Facility/Site
Activity Details Cold Canyon Landfill, Inc. (40-AA-0004).
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/1509?siteID=3171
(accessed July 2024).
California Department of Toxic Substances Control (DTSC). 2024. EnviroStor.
https://www.envirostor.dtsc.ca.gov/public/map/?myaddress=san+luis+obispo (accessed
July 2024).
California Department of Transportation (Caltrans). 2019. California State Scenic Highway System
Map. https://dot.ca.gov/programs/design/lap-landscape-architecture-and-community-
livability/lap-liv-i-scenic-highways (accessed July 2024).
______. 2020. Transportation and Construction Vibration Guidance Manual. https://dot.ca.gov/-
/media/dot-media/programs/environmental-analysis/documents/env/tcvgm-apr2020-
a11y.pdf (accessed August 2024).
California Department of Water Resources (DWR). 2022. SGMA Basin Prioritization Dashboard.
https://gis.water.ca.gov/app/bp-dashboard/final/ (accessed July 2024).
California Geological Survey (CGS). 2024. EQ Zapp: California Earthquake Hazard Zones Application.
https://maps.conservation.ca.gov/cgs/EQZApp/app/ (accessed July 2024).
City of San Luis Obispo
Groundwater Contamination Characterization Project
96
City of San Luis Obispo. 2014a. Land Use and Circulation Element Update Volume I Draft Program
EIR. June 2014.
https://www.slocity.org/home/showpublisheddocument/6723/635671221997970000
(accessed July 2024).
______. 2014b. Conservation and Open Space Element.
https://www.slocity.org/home/showpublisheddocument/6651/635670212786530000
(accessed July 2024).
______. 2014c. Safety Element. December 9, 2014.
https://www.slocity.org/home/showpublisheddocument/6645/635670212766530000
(accessed July 2024).
______. 2020a. Climate Action Plan For Community Recovery.
https://www.slocity.org/government/department-directory/city-administration/office-of-
sustainability-and-natural-resources/climate-action/climate-action-plan (accessed August
2024).
______. 2020b. Standard Specifications & Engineering Standards.
https://www.slocity.org/home/showpublisheddocument/27919/637341402080900000
(accessed July 2024).
______. 2020c. Transportation Impact Study Guidelines.
https://www.slocity.org/home/showpublisheddocument/26883/637290299618070000
(accessed August 2024).
______. 2021. Parks + Recreation Blueprint for the Future: 2021-2041. July 2021.
https://www.slocity.org/home/showpublisheddocument/29503/637690273249070000
(accessed July 2024).
______. 2024a. San Luis Obispo Bike Map.
https://slocity.maps.arcgis.com/apps/Viewer/index.html?appid=26dbd38b9b46474a9f067a
ce6a453fc4 (accessed August 2024).
______. 2024b. SLO Transit Rider Portal. https://slo.rider.peaktransit.com/ (accessed August 2024).
______. 2024c. Wastewater Treatment. https://www.slocity.org/government/department-
directory/utilities-department/wastewater/wastewater-treatment (accessed July 2024).
______. 2024d. Current Development Projects.
https://storymaps.arcgis.com/stories/d6ad7b71ca324c5b95773617e182a042 (accessed
September 2024).
______. 2024e. 2020 Urban Water Management Plan.
https://www.slocity.org/home/showpublisheddocument/31041/637673768464130000
(accessed September 2024).
City of San Luis Obispo Department of Public Works. 2022. Interactive Data Viewer.
https://gis.slocounty.ca.gov/Html5Viewer/Index.html?configBase=/Geocortex/Essentials/RE
ST/sites/PW_SGMA/viewers/PW_Viewer/virtualdirectory/Resources/Config/Default&Layer
Theme=3 (accessed July 2024).
References
Initial Study – Mitigated Negative Declaration 97
Federal Emergency Management Agency (FEMA). 2024. National Flood Hazard Layer.
https://hazards-
fema.maps.arcgis.com/apps/webappviewer/index.html?id=8b0adb51996444d4879338b552
9aa9cd (accessed July 2024).
Jennings, C. 1958. Geologic Map of California San Luis Obispo Sheet.
https://www.conservation.ca.gov/cgs/Documents/Publications/Geologic-Atlas-
Maps/GAM_18-SanLuisObispo-1958-Map.pdf (accessed September 2024).
RS&H. 2021. Amended and Restated San Luis Obispo County Regional Airport – Airport Land Use
Plan. Accessible at: https://sloairport.com/wp-
content/uploads/2024/02/Airport_Land_Use_Plan_Amended_5-26-21.pdf (accessed July
2024).
San Luis Obispo Air Pollution Control District (SLOAPCD). 2001. Clean Air Plan.
https://storage.googleapis.com/slocleanair-
org/images/cms/upload/files/business/pdf/CAP.pdf (accessed August 2024).
______. 2005. Particulate Matter Report Implementation of SB 656 Requirements.
https://storage.googleapis.com/slocleanair-org/images/cms/upload/files/PM.ReportFin.pdf
(accessed August 2024).
______. 2018. SLO APCD NOA Screening.
https://www.google.com/maps/d/u/0/viewer?mid=1YAKjBzVkwi1bZ4rQ1p6b2OMyvIM&ll=
35.364986805363785%2C-120.52563349999998&z=10 (accessed August 2024).
______. 2019. San Luis Obispo County Attainment Status.
https://storage.googleapis.com/slocleanair-
org/images/cms/upload/files/AttainmentStatus29January2019.pdf (accessed August 2024).
______. 2020. Ozone Emergency Episode Plan. https://storage.googleapis.com/slocleanair-
org/images/cms/upload/files/San%20Luis%20Obispo%20County%20Ozone%20Emergency%
20Episode%20Plan%2022%20January%202020.pdf (accessed August 2024).
______. 2023. CEQA Air Quality Handbook. https://storage.googleapis.com/slocleanair-
org/images/cms/upload/files/CEQA%20Handbook%202023_Final.pdf (accessed August
2024).
San Luis Obispo Fire Department (SLOFD). 2023. 2023 Annual Report.
https://www.slocity.org/home/showpublisheddocument/35237/638518006009370000
(accessed July 2024).
San Luis Obispo Police Department (SLOPD). 2024. About the Department.
https://www.slocity.org/government/department-directory/police-department/about-the-
department (accessed July 2024).
Society of Vertebrate Paleontology (SVP). 2010. Standard Procedures for the Assessment and
Mitigation of Adverse Impacts to Paleontological Resources. https://vertpaleo.org/wp-
content/uploads/2021/01/SVP_Impact_Mitigation_Guidelines-1.pdf (accessed July 2024).
State Water Resources Control Board (SWRCB). 2022. GeoTracker.
https://geotracker.waterboards.ca.gov/map/?CMD=runreport&myaddress=city+of+san+luis
+obsipo (accessed July 2024).
City of San Luis Obispo
Groundwater Contamination Characterization Project
98
United States Department of Agriculture (USDA). 2024. Web Soil Survey.
https://websoilsurvey.sc.egov.usda.gov/app/WebSoilSurvey.aspx (accessed July 2024).
United States Environmental Protection Agency (U.S.EPA). 2024. Superfund Enterprise Management
System. July 1, 2024. https://enviro.epa.gov/envirofacts/sems/search (accessed July 2024).
List of Preparers
Rincon Consultants, Inc. prepared this IS-MND under contract to the City of San Luis Obispo. Persons
involved in data gathering analysis, project management, and quality control are listed below.
Rincon Consultants, Inc.
Richard Daulton, MURP, Vice President/Senor Principal
Megan Jones, Principal
Chris Bersbach, MESM, Senior Supervising Planner
Nik Kilpelainen, Environmental Planner
Ethan Knox, Environmental Planner
Bryan Valladares, GIS Analyst
Debra Jane Seltzer, Formatting Specialist