Initial Study and Mitigated Negative Declaration
(IS/MND)
Municipal Code Text Amendment 20-0005 San Dimas
MCTA 20-0005
Prepared for:
CITY OF SAN DIMAS
City of San Dimas Planning Division
Ken Fichtelman, Associate Planner
245 E. Bonita Avenue
San Dimas, CA 91773
Telephone: (909) 394-6256
Prepared by:
UltraSystems Environmental Inc.
16431 Scientific Way
Irvine, CA 92618-4355
Telephone: 949.788.4900
FAX: 949.788.4901
www.ultrasystems.com
December 2022
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❖ PROJECT INFORMATION SHEET ❖
PROJECT INFORMATION SHEET
1. Project Title Municipal Code Text Amendment
San Dimas MCTA 20-0005
2. CEQA Lead Agency and City of San Dimas
245 East Bonita Avenue
San Dimas, CA 91773
Address
3. Contact and Phone
Number
Ken Fichtelman, Associate Planner
City of San Dimas
(909) 394-6256
[email protected]
4. Project Applicant
5. Project Location
City of San Dimas
245 East Bonita Avenue
San Dimas, CA 91773
Planning Area 1 within Specific Plan 11.
West of Via Verde, south of Puente Street and north of
Covina Hills Road
6. Project Site General Plan
Designation(s)
Single Family Very Low
7. Project Site Zoning Specific Plan 11 (SP-11)
Designation(s)
8. Surrounding Land Uses The site is bounded by Covina Hills Road to the south, single-family residential uses and vacant land in the city of Covina and unincorporated Los Angeles County to the west, single-family residences opposite Puente Street to the
north, and single-family residences and vacant land to the east. The project site is on and near a hillcrest in the San Jose Hills.
and Setting
9. Description of Project The proposed Municipal Code Text Amendment (MCTA) would allow for up to one thousand (1,000) cubic yards of grading, cut and fill, beyond that grading necessary for the primary residence, driveway and garage for properties
located within SP-11 Planning Area 1 (36 residential lots, up to 36,000 CY grading). Per the previous Development
Plan Review Board policy, a swimming pool and five (5) feet of decking surrounding the pool were exempted from the
additional grading calculations, and will be codified as part of the proposed MCTA. The proposed MCTA would also
include development standards for the grading,
landscaping and any retaining walls that the additional grading would require. Additional clean-up items are
7145/San Dimas MCTA 20-0005 Page i
Initial Study/Mitigated Negative Declaration Page 982 – 2053 December 2022 ❖ PROJECT INFORMATION SHEET ❖
proposed by removing sections which dealt with the initial development of the area and codifying previous policies regarding Conditional Uses within the specific plan.
10. Selected Agencies whose
Approval is Required
City of San Dimas
11. Have California Native
American tribes
Letters were sent by the City of San Dimas (the Lead
Agency), to seven local Native American Tribes on May 22, 2022 asking if they wished to participate in AB 52 and SB 18 consultation concerning the proposed project in the City of San Dimas.
traditionally and
culturally affiliated with
the project area requested
consultation pursuant to
Public Resources Code
§ 21080.3.1? If so, has
consultation begun?
The AB 52 notice period for the Tribes is 30 days and the SB 18 notice period for the Tribes is 90 days during which they have an opportunity to respond to notification of this
proposed project.
For the proposed project, the periods of notification have passed and no tribes requested consultation with the City per Public Resources Code § 21074. The consultation has been concluded.
12. Other Public Agencies
whose Approval is
Required
None.
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Table of Contents
PROJECT INFORMATION SHEET ........................................................................................................................ i Table of Contents..................................................................................................................................................iii ACRONYMS AND ABBREVIATIONS..................................................................................................................vi
1.0 INTRODUCTION....................................................................................................................................1-1
1.1 1.2
1.3 1.4
1.5 1.6
1.7 1.8
Proposed Project.................................................................................................................................. 1-1 Lead Agencies – Environmental Review Implementation.................................................. 1-1 CEQA Overview..................................................................................................................................... 1-1 Purpose of Initial Study..................................................................................................................... 1-2 Review and Comment by Other Agencies.................................................................................. 1-3 Impact Terminology ........................................................................................................................... 1-3 Organization of Initial Study ........................................................................................................... 1-4 Findings from the Initial Study....................................................................................................... 1-4
2.0 3.0
4.0 ENVIRONMENTAL SETTING .............................................................................................................2-1
2.1 2.2
2.3 Project Location.................................................................................................................................... 2-1 Project Setting ....................................................................................................................................... 2-1 Existing Characteristics of the Site ............................................................................................... 2-6 PROJECT DESCRIPTION.....................................................................................................................3-1
3.1 3.2
3.3 Project Location and Existing Conditions.................................................................................. 3-1 Project Overview.................................................................................................................................. 3-1 Discretionary and Ministerial Approvals................................................................................... 3-5 ENVIRONMENTAL CHECKLIST ........................................................................................................4-1
4.1 4.2
4.3 4.4
4.5 4.6
4.7 4.8
4.9 Aesthetics.............................................................................................................................................4.1-1 Agriculture and Forestry Resources.........................................................................................4.2-1 Air Quality............................................................................................................................................4.3-1 Biological Resources........................................................................................................................4.4-1 Cultural Resources ...........................................................................................................................4.5-1 Energy....................................................................................................................................................4.6-1 Geology and Soils ..............................................................................................................................4.7-1 Greenhouse Gas Emissions ...........................................................................................................4.8-1 Hazards and Hazardous Materials.............................................................................................4.9-1
4.10 Hydrology and Water Quality...................................................................................................4.10-1
4.11 Land Use and Planning ................................................................................................................4.11-1
4.12 Mineral Resources.........................................................................................................................4.12-1
4.13 Noise....................................................................................................................................................4.13-1
4.14 Population and Housing..............................................................................................................4.14-1
4.15 Public Services ................................................................................................................................4.15-1
4.16 Recreation.........................................................................................................................................4.16-1
4.17 Transportation................................................................................................................................4.17-1
4.18 Tribal Cultural Resources...........................................................................................................4.18-1
4.19 Utilities and Service Systems ....................................................................................................4.19-1
4.20 Wildfire ..............................................................................................................................................4.20-1
4.21 Mandatory Findings of Significance.......................................................................................4.21-1 7145/San Dimas MCTA 20-0005 Page iii
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5.0 6.0
REFERENCES..........................................................................................................................................5-1 List of Preparers ..................................................................................................................................6-1
6.1 6.2
6.3 Lead Agency (CEQA)........................................................................................................................... 6-1 Project Applicant.................................................................................................................................. 6-1 UltraSystems Environmental, Inc.................................................................................................. 6-1
7.0 Mitigation Monitoring and Reporting Program .......................................................................7-1
LIST OF FIGURES
Figure 2.1-1 - Regional Location.................................................................................................................................. 2-3 Figure 2.1-2 - Project Location..................................................................................................................................... 2-4 Figure 2.2-2 - Project Site Photographs.................................................................................................................... 2-5 Figure 3.1-1 – Specific Plan No. 11 Location Map ................................................................................................ 3-2 Figure 3.1-2 – Project Parcel Map............................................................................................................................... 3-3 Figure 3.2-1 - Proposed Site Plan................................................................................................................................ 3-5 Figure 4.1-1 – Photo Location Map..........................................................................................................................4.1-3 Figure 4.1-2 -Photos of the Surrounding Project Area (1-4)........................................................................4.1-4 Figure 4.1-3 -Photos of the Surrounding Project Area (5-8)........................................................................4.1-5 Figure 4.1-4 -Photos of the Surrounding Project Area (9-12)......................................................................4.1-6 Figure 4.1-5 - Scenic Highways.................................................................................................................................4.1-1 Figure 4.2-1 - Important Farmland .........................................................................................................................4.2-2 Figure 4.2-2 - Williamson Act Lands.......................................................................................................................4.2-4 Figure 4.4-1 – Biological Study Area (BSA)..........................................................................................................4.4-4 Figure 4.4-2 – Residential Lots and Associated Assessor’s Parcel Numbers (APNs) .........................4.4-7 Figure 4.4-3 - CNDDB Known Occurances: Plant Species and Habitat..................................................4.4-11 Figure 4.4-4 - CNDDB Known Occurrences: Wildlife Species and Habitat...........................................4.4-14 Figure 4.4-5 – Land Cover Types...........................................................................................................................4.4-35 Figure 4.4-6 – Biological Constraints...................................................................................................................4.4-42 Figure 4.4-7 – CDFW Wildlife Corridors ............................................................................................................4.4-45 Figure 4.4-8 – Significant Ecological Areas (SEAs)........................................................................................4.4-50 Figure 4.4-9 – USFWS Critical Habitats .................................................................................................................4.4-0 Figure 4.5-1 - Topographic Map ...............................................................................................................................4.5-2 Figure 4.7-1 – Alquist Priolo Fault Zones..............................................................................................................4.7-4 Figure 4.7-2 - Regionally Active Faults..................................................................................................................4.7-5 Figure 4.7-3 – Landslides and Liquefaction.........................................................................................................4.7-7 Figure 4.9-1 - Brackett Field Airport Influence Area .......................................................................................4.9-4 Figure 4.9-2 - Fire Hazard Severity Zone - State Responsibility Area.......................................................4.9-6 Figure 4.9-3 - Fire Hazard Severity Zone – Local Responsibility Area.....................................................4.9-7 Figure 4.11-1 - Project Site Current General Plan Land Use Designations..........................................4.11-2 Figure 4.11-2 - Project Site Current Zoning Designations..........................................................................4.11-3 Figure 4.12-1 – Mineral Resources.......................................................................................................................4.12-2 Figure 4.12-2 - Oil and Gas Wells and Fields....................................................................................................4.12-3 Figure 4.12-3- Geothermal Wells..........................................................................................................................4.12-4 Figure 4.16-1 – Nearby Parks and Recreational Facilities..........................................................................4.16-2 Figure 4.19-1 - Los Angeles County Storm Facilities Map ..........................................................................4.19-3 Figure 4.20-1 - Fire Hazard Severity Zone - State Responsibility Area.................................................4.20-2 Figure 4.20-2 - Fire Hazard Severity Zone - Local Responsibility Area................................................4.20-3 7145/San Dimas MCTA 20-0005 Page iv
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Figure 4.20-3 – Los Angeles County Disaster Routes Map for the City of San Dimas......................4.20-4
LIST OF TABLES
Table 2.2-1 - Summary of Land Use and Zoning ................................................................................................... 2-1 Table 3.2-1 – Grading Permitted Under Existing Specific Plan and Proposed Amendments............. 3-4 Table 4.1-1 - Project Compliance with City of San Dimas General Plan Policies Regarding Scenic Quality and Aesthetics....................................................................................................................................................4.1-2 Table 4.3-1 - Federal and State Attainment Status...........................................................................................4.3-3 Table 4.3-2 - Ambient Air Quality Monitoring Data .........................................................................................4.3-4 Table 4.3-3 - SCAQMD Emissions Thresholds for Significant Regional Impacts ..................................4.3-5 Table 4.3-5 - Maximum Daily Regional Construction Emissions ................................................................4.3-6 Table 4.3-7 - Results of Localized Significance Analysis.................................................................................4.3-8 Table 4.4-1 – Residential Lots and Associated Assessor’s Parcel Numbers (APNs)...........................4.4-8 Table 4.4-2 – Residential Lots and Associated Mitigation Measures .....................................................4.4-22 Table 4.6-1 - Estimated Project Operational Energy Use...............................................................................4.6-3 Table 4.7-1 – Paleontological Records Search Results.................................................................................4.7-10 Table 4.13-2 - California Land Use Compatibility for Community Noise Sources ............................4.13-3 Table 4.14-1 - City of San Dimas Demographic Forecast............................................................................4.14-1 Table 4.14-2 - City of San Dimas Demographic Estimates..........................................................................4.14-2 Table 4.119-2 GSWC San Dimas System Water Supplies and Demands, Average Water Conditions ...............................................................................................................................................................................................4.19-5 Table 4.19-3 - GSWC Water Supplies and Demands, Single Year Conditions.....................................4.19-5 Table 4.19-4 - GSWC Water Supplies and Demands, Multiple Dry Year Conditions .......................4.19-5 Table 4.19-5 - Landfills Serving San Dimas ......................................................................................................4.19-6 Table 7.0-1 - Mitigation Monitoring and Reporting Program ......................................................................... 7-2
APPENDICES
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G
Planning Area 1 Lot Coverage Calculations
AQ/GHG Report
Biological Resources Assessment
Cultural Phase I Report
Fuel Consumption Analysis
Paleontological Records Search
Hydrology/Drainage Report
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ACRONYMS AND ABBREVIATIONS
Acronym/Abbreviation Term
°F
AB
degrees Fahrenheit
Assembly Bill
AB 32
AB 939
AB 1327
ADA
California Global Warming Solutions Act of 2006
California Integrated Waste Management Act
California Solid Waste Reuse and Recycling Access Act of 1991 Americans with Disabilities Act
ADT average daily traffic
AMSL
APE
above mean sea level
area of potential effect
APN Assessor’s Parcel Number
AQMP
ARB
Air Quality Management Plan
California Air Resources Board
AST aboveground storage tank
ASTM
ATP
American Society for Testing and Materials
Active Transportation Plan
bgs below ground surface
BMPs
CAAQS
Cal/OSHA
CalEEMod
CAL FIRE
CALGreen
Caltrans
CAPCOA
CAOs
Best Management Practices
California Ambient Air Quality Standards
California Division of Occupational Safety and Health
California Emissions Estimator Model
California Department of Forestry and Fire Protection
California Green Building Standards
California Department of Transportation
California Air Pollution Control Officers Association
Cleanup and Abatement Orders
CBC California Building Code
CCAA
CCR
California Clean Air Act
California Code of Regulations
CDOs Cease and Desist Orders
CDFW
CEQA
CERCLA
California Department of Fish & Wildlife
California Environmental Quality Act
Comprehensive Environmental Response, Compensation, and Liability Act
CESA
CFR
California Endangered Species Act
Code of Federal Regulations
CGS California Geologic Society
CH4 methane
CHP California Highway Patrol
CHRIS
CIWMA
CMP
CNDDB
CNEL
CNRA
California Historic Resources Inventory System
State of California Integrated Waste Management Act
Congestion Management Program
California Natural Diversity Database
Community Noise Equivalent Level
California Natural Resources Agency
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Acronym/Abbreviation Term
CO Carbon monoxide
CO2 carbon dioxide
CO2e
CRC
carbon dioxide equivalent
California Residential Code
CRHR
CWA
dB
California Register of Historic Resources
Clean Water Act
decibel
dBA
DIF
A-weighted decibel scale
Development Impact Fees
drainage management area
California Department of Conservation
California Division of Safety and Health
Design Review Project
Department of Toxic Substances Control
Environmental Impact Report
Emergency Medical Service
Emergency Operations Plan
Endangered Species Act
DMA
DOC
DOSH
DRP
DTSC
EIR
EMS
EOP
ESA
ESA Environmental Site Assessment
FAR floor area ratio
FHSZ
FMMP
FRAP
FTA
GHG
GPCD
GWP
GWTS
HAZNET
HCP
HFCs
Hz
Fire Hazard Severity Zones
Farmland Mapping and Monitoring Program
CalFire Fire Resource and Assessment Program
Federal Transit Administration
greenhouse gas
gallons per capita per day
global warming potential
groundwater treatment system
Hazardous Waste Tracking System
Habitat Conservation Plan
hydrofluorocarbons
hertz
IFC International Fire Code
I-L Light Industrial General Plan Land Use Designation
Intergovernmental Panel on Climate Change
Initial Study/Mitigated Negative Declaration
killowatt hours
noise level that is exceeded 90% of the time
equivalent noise level
IPCC
IS/MND
kWh
L90
Leq
LED
LHMP
LID
light-emitting diode
Local Hazard Mitigation Plan
Low Impact Development
Lmax
LOS
root mean square maximum noise level
Level of Service
LRA
LRP
Local Responsibility Area
Legally Responsible Person
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Acronym/Abbreviation Term
LSTs Localized Significance Thresholds
LUST
M-1
MBTA
MCR
Leaking Underground Storage Tank
Light Industrial zoning designation
Migratory Bird Treaty Act
Master Case No.
MCTA
MLD
Municipal Code Text Amendment
Most Likely Descendant
MM(s)
MMRP
MMT
MMTCO2e
MND
MRZ
mitigation measure(s)
Mitigation Monitoring and Reporting Program
million metric tons
million metric tons of CO2e
Mitigated Negative Declaration
Mineral Resource Zone
MS4
MWD
N2O
municipal separate storm sewer systems
Metropolitan Water District of Southern California
nitrous oxide
NAAQS
NAHC
NCCP
ND
National Ambient Air Quality Standards
Native American Heritage Commission
Natural Communities Conservation Plan
Negative Declaration
NHPA
NO
National Historic Preservation Act
nitric oxide
NO2 nitrogen dioxide
NOx Nitrogen oxides
NOI Notice of Intent
NPDES
NPPA
NRCS
NRHP
O3
National Pollutant Discharge Elimination System
Native Plant Protection Act
Natural Resources Conservation Service
National Register of Historic Places
Ozone
OPR
OSHA
Pb
Governor’s Office of Planning and Research
Occupational Safety and Health Administration
lead
PFCs
PM
perfluorocarbons
particulate matter
PM2.5
PM10
Porter-Cologne
PPM
fine particulate matter
respirable particulate matter
Porter-Cologne Water Quality Control Act
parts per million
PPV peak particle velocity
PRDs
PRP
Qyf5
RCRA
REC(s)
RMS
Permit Registration Documents
potential responsible party
Young Alluvial Fan Deposits, unit 5
Resource Conservation and Recovery Act
recognized environmental condition(s)
root mean square
7145/San Dimas MCTA 20-0005 Page viii
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Acronym/Abbreviation Term
ROG
ROW
RP
Reactive organic gases
right-of-way
Regional Plant
RWQCB
SARWQCB
SCAB
SCAG
SCAQMD
SCCIC
SCE
Regional Water Quality Control Board
Santa Ana Regional Water Quality Control Board
South Coast Air Basin
Southern California Association of Governments
South Coast Air Quality Management District
South Central Coastal Information Center
Southern California Edison
SF6 sulfur hexafluoride
SIP State Implementation Plan
SLF Sacred Lands File
SMARTS
SO2
Stormwater Multi-Application and Report Tracking System sulfur dioxide
SoCalGas
SOPs
SR
Southern California Gas Company
Standard Operating Procedures
State Route
SRA State Responsibility Area
SRAs source receptor areas
STIP
SUSMP
SVE
Statewide Transportation Improvement Program
Standard Urban Stormwater Mitigation Plan
soil vapor extraction
SWP California State Water Project
California State Water Resources Control Board
Stormwater Pollution Prevention Plan
tribal cultural resources
SWRCB
SWPPP
TCRs
TMP Traffic Management Plan
USDA
USGS
USEPA
UWMP
VdB
United States Department of Agriculture
United States Geological Survey
United States Environmental Protection Agency
Urban Water Management Plan
vibration decibels
VHFHSZs
VMT
very high fire hazard severity zones
vehicle miles traveled
VOC volatile organic compound
WEAP
WQMP
WOUS
Worker Environmental Awareness Program
Water Quality Management Plan
Water(s) of the United States
7145/San Dimas MCTA 20-0005 Page ix
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1.0 1.1
INTRODUCTION
Proposed Project
The proposed Municipal Code Text Amendment (MCTA) would allow for up to one thousand (1,000) cubic yards of grading, cut and fill, beyond that grading necessary for the primary residence, driveway and garage for properties located within SP-11 Planning Area 1 (36 residential lots, up to 36,000 CY grading). Per the previous Development Plan Review Board policy, a swimming pool and five (5) feet of decking surrounding the pool were exempted from the additional grading calculations, and will be codified as part of the proposed MCTA. The proposed MCTA would also include development standards for the grading, landscaping and any retaining walls that the additional grading would require. Additional clean-up items are proposed by removing sections which dealt with the initial development of the area and codifying previous policies regarding Conditional Uses within the specific plan.
1.2 Lead Agencies – Environmental Review Implementation The City of San Dimas is the Lead Agency for the proposed project. Pursuant to the California Environmental Quality Act (CEQA) and its implementing regulations,1 the Lead Agency has the principal responsibility for implementing and approving a project that may have a significant effect on the environment.
1.3 CEQA Overview
1.3.1 Purpose of CEQA
All discretionary projects within California are required to undergo environmental review under CEQA. A Project is defined in CEQA Guidelines § 15378 as the whole of the action having the potential to result in a direct physical change or a reasonably foreseeable indirect change to the environment and is any of the following:
• An activity directly undertaken by any public agency including but not limited to public works construction and related activities clearing or grading of land, improvements to existing public structures, enactment and amendment of zoning ordinances, and the adoption and amendment of local General Plans or elements.
•
•
An activity undertaken by a person which is supported in whole or in part through public agency contracts, grants, subsidies, loans, or other forms of assistance from one or more public agencies.
An activity involving the issuance to a person of a lease, permit, license, certificate, or other entitlement for use by one or more public agencies.
CEQA Guidelines § 15002 lists the basic purposes of CEQA as follows:
•
•
Inform governmental decision makers and the public about the potential, significant environmental effects of proposed activities.
Identify the ways that environmental damage can be avoided or significantly reduced. 1 Public Resources Code §§ 21000 - 21177 and California Code of Regulations Title 14, Division 6, Chapter 3. 7145/San Dimas MCTA 20-0005 Page 1-1
Initial Study/Mitigated Negative Declaration Page 991 – 2053 December 2022 ❖ SECTION 1.0 - INTRODUCTION ❖
•
•
Prevent significant, avoidable damage to the environment by requiring changes in projects through the use of alternatives or mitigation measures when the governmental agency finds the changes to be feasible.
Disclose to the public the reasons why a governmental agency approved the project in the manner the agency chose if significant environmental effects are involved.
1.3.2 Authority to Mitigate under CEQA
CEQA establishes a duty for public agencies to avoid or minimize environmental damage where feasible. Under CEQA Guidelines § 15041 a Lead Agency for a project has authority to require feasible changes in any or all activities involved in the project in order to substantially lessen or avoid significant effects on the environment, consistent with applicable constitutional requirements such as the “nexus”2 and “rough proportionality”3 standards.
CEQA allows a Lead Agency to approve a project even though the project would cause a significant effect on the environment if the agency makes a fully informed and publicly disclosed decision that there is no feasible way to lessen or avoid the significant effect. In such cases, the Lead Agency must specifically identify expected benefits and other overriding considerations from the project that outweigh the policy of reducing or avoiding significant environmental impacts of the project.
1.4 Purpose of Initial Study
The CEQA process begins with a public agency making a determination as to whether the project is subject to CEQA at all. If the project is exempt, the process does not need to proceed any farther. If the project is not exempt, the Lead Agency takes the second step and conducts an Initial Study to determine whether the project may have a significant effect on the environment.
The purposes of an Initial Study as listed in § 15063(c) of the CEQA Guidelines are to:
• Provide the Lead Agency with information necessary to decide if an Environmental Impact Report (EIR), Negative Declaration (ND), or Mitigated Negative Declaration (MND) should be prepared.
•
•
Enable a Lead Agency to modify a project to mitigate adverse impacts before an EIR is prepared, thereby enabling the project to qualify for a ND or MND.
Assist in the preparation of an EIR, if required, by focusing the EIR on adverse effects determined to be significant, identifying the adverse effects determined not to be significant, explaining the reasons for determining that potentially significant adverse effects would not be significant, and identifying whether a program EIR, or other process, can be used to analyze adverse environmental effects of the project.
•
•
Facilitate an environmental assessment early during project design.
Provide documentation in the ND or MND that a project would not have a significant effect on the environment.
•
•
Eliminate unnecessary EIRs.
Determine if a previously prepared EIR could be used for the Project. 2 3
A nexus (i.e., connection) must be established between the mitigation measure and a legitimate governmental interest.
The mitigation measure must be “roughly proportional” to the impacts of the Project. 7145/San Dimas MCTA 20-0005 Page 1-2
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In cases where no potentially significant impacts are identified, the Lead Agency may issue a ND, and no mitigation measures would be needed. Where potentially significant impacts are identified, the Lead Agency may determine that mitigation measures would adequately reduce these impacts to less than significant levels. The Lead Agency would then prepare an MND for the proposed project. If the Lead Agency determines that individual or cumulative effects of the proposed project would cause a significant adverse environmental effect that cannot be mitigated to less than significant levels, then the Lead Agency would require an EIR to further analyze these impacts.
1.5 Review and Comment by Other Agencies
Other public agencies are provided the opportunity to review and comment on the IS/MND. Each of these agencies is described briefly below.
• A Responsible Agency (14 CCR § 15381) is a public agency, other than the Lead Agency, that has discretionary approval power over the Project, such as permit issuance or plan approval authority.
•
•
A Trustee Agency4 (14 CCR § 15386) is a state agency having jurisdiction by law over natural resources affected by a project that are held in trust for the people of the State of California.
Agencies with Jurisdiction by Law (14 CCR § 15366) are any public agencies who have authority (1) to grant a permit or other entitlement for use; (2) to provide funding for the project in question; or (3) to exercise authority over resources which may be affected by the project. Furthermore, a city or county will have jurisdiction by law with respect to a project when the city or county having primary jurisdiction over the area involved is: (1) the site of the project; (2) the area in which the major environmental effects will occur; and/or (3) the area in which reside those citizens most directly concerned by any such environmental effects.
1.6 Impact Terminology
The following terminology is used to describe the level of significance of potential impacts:
•
•
A finding of no impact is appropriate if the analysis concludes that the project would not affect the particular environmental threshold in any way.
An impact is considered less than significant if the analysis concludes that the project would cause no substantial adverse change to the environment and requires no mitigation.
•
•
An impact is considered less than significant with mitigation incorporated if the analysis concludes that the project would cause no substantial adverse change to the environment with the inclusion of environmental commitments, or other enforceable measures, that would be adopted by the lead agency.
An impact is considered potentially significant if the analysis concludes that the project could have a substantial adverse effect on the environment.
An EIR is required if an impact is identified as potentially significant. 4 The four Trustee Agencies in California listed in CEQA Guidelines § 15386 are California Department of Fish and Wildlife, State Lands Commission, State Department of Parks and Recreation, and University of California. 7145/San Dimas MCTA 20-0005 Page 1-3
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1.7 Organization of Initial Study
This IS/MND is organized to satisfy CEQA Guidelines § 15063(d), and includes the following sections:
•
•
Section 1.0 - Introduction, which identifies the purpose and scope of the IS/MND.
Section 2.0 - Environmental Setting, which describes location, existing site conditions, land uses, zoning designations, topography, and vegetation associated with the project site and surrounding area.
•
•
Section 3.0 - Project Description, which provides an overview of the project, a description of the proposed development, project phasing during construction, and discretionary actions for the approval of the project.
Section 4.0 - Environmental Checklist, which presents checklist responses for each resource topic to identify and assess impacts associated with the proposed project, and proposes mitigation measures, where needed, to render potential environmental impacts less than significant, where feasible.
•
•
Section 5.0 - References, which includes a list of documents cited in the IS/MND.
Section 6.0 - List of Preparers, which identifies the primary authors and technical experts that prepared the Initial Study.
• Section 7.0 – Mitigation, Monitoring, and Reporting Program, which identifies the mitigation measures for the proposed project, the responsible/monitoring party, the monitoring action, enforcement agency, monitoring agency, and monitoring phase.
Technical studies and other documents, which include supporting information or analyses used to prepare this IS/MND, are included in the following appendices:
•
•
•
•
•
•
•
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G
Planning Area 1 Lot Coverage Calculations
AQ/GHG Report
Biological Resources Assessment
Cultural Phase I Report
Fuel Consumption Analysis
Paleontological Records Search
Hydrology/Drainage Report
1.8 Findings from the Initial Study
1.8.1 No Impact or Impacts Considered Less than Significant The project would have no impact or a less than significant impact on the following environmental categories listed from Appendix G of the CEQA Guidelines. •
•
•
•
•
•
•
•
Aesthetics
Air Quality
Agriculture and Forestry Resources
Energy
Greenhouse Gas Emissions
Hazards and Hazardous Materials
Land Use and Planning
Mineral Resources
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•
•
•
•
•
•
•
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Noise
Population and Housing
Public Services
Recreation
Tribal Cultural Resources
Transportation and Traffic
Utilities and Service Systems
Wildfire
1.8.2 Impacts Considered Less than Significant with Mitigation Measures Based on IS findings, the project would have a less than significant impact on the following environmental categories listed in Appendix G of the CEQA Guidelines when proposed mitigation measures are implemented.
•
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•
•
•
Biological Resources
Cultural Resources
Geology and Soils
Hydrology and Water Quality
Mandatory Findings of Significance
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2.0 ENVIRONMENTAL SETTING
2.1 Project Location
The project site is approximately 92 acres in the southwest part of the city of San Dimas. Regional access to the site is from Interstate 10, (I-10 or the San Bernardino Freeway) via Via Verde, Covina Hills Road, and Calle Francesca. Figure 2.1-1 shows the regional location of the project site.
The project site is bounded by Covina Hills Road to the south; single-family residential uses and vacant land in the city of Covina and unincorporated Los Angeles County to the west; single-family residences opposite Puente Street to the north; and single-family residences and vacant land to the east.
The site includes 36 single-family residential parcels, 29 of which are developed and seven vacant.
Address numbers on Calle Cristina range from 1508 at the southeast end of the site to 1620 at the northwest end. Address numbers on Paseo Lucinda range from 2050 at the east end to 2069 at the west end.
2.2 Project Setting
The site is subdivided into 36 lots for single-family residential use, totaling approximately 90 acres; 29 lots are developed with single-family residences and seven are vacant. The vacant lots are vegetated with grasses and scattered trees and shrubs. The two roadways within the project site are Calle Cristina, along which most of the lots are located; and Paseo Lucinda in the northern part of the site. Expansive views of the San Gabriel Mountains to the north, the Puente Hills to the south, and other parts of the San Jose Hills, are visible from the site, especially the vacant lots.
2.2.1 Land Use and Zoning
The land use designation and zoning of the project site and surrounding areas are listed in Table 2.2-1. The General Plan land use designation for the project site is Single Family Very Low and the zoning designation for the site is Specific Plan 11 (SP-11).
Table 2.2-1
SUMMARY OF LAND USE AND ZONING
Location General Plan Zoning
Specific Plan 11
Existing Use
Single-family residential and
vacant
Project Site Single Family Very Low
Surrounding Areas
North
East
Single Family Low Single-Family (SF)
Specific Plan 11
Single-family residential
Single-family residential uses
and vacant Single Family Very Low
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Location General Plan Zoning Existing Use
West (City of
Covina) Single-Family Residential
(R-1)
Single-family residential uses
and vacant Residential Low Density
West
(Unincorporated
Los Angeles
County)
Light Agricultural
(A-1-20000)
Single-family residential uses
and vacant Residential 2 (H2)
South
(Unincorporated Light Agricultural
(A-1-20000)
Single-family residential uses
and vacant Los Angeles Residential 2 (H2)
County)
Source: City of San Dimas 2021; City of San Dimas 2003; City of Covina, 2021; City of Covina, 2000 7145/San Dimas MCTA 20-0005 Page 2-2
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Figure 2.1-1
REGIONAL LOCATION
7145/San Dimas MCTA 20-0005
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Figure 2.1-2
PROJECT LOCATION
7145/San Dimas MCTA 20-0005
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Figure 2.2-2
PROJECT SITE PHOTOGRAPHS
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2.3 Existing Characteristics of the Site
2.3.1 Climate and Air Quality
The project site is located within the South Coast Air Basin (SCAB), which includes all of Orange County, as well as the non-desert portions of Los Angeles, Riverside, and San Bernardino Counties.
The distinctive climate of the SCAB is determined by its terrain and geographical location. The SCAB is in a coastal plain with connecting broad valleys and low hills, bounded by the Pacific Ocean in the southwest quadrant with high mountains forming the remainder of the perimeter. The general region lies in the semi-permanent high-pressure zone of the eastern Pacific. Thus, the climate is mild, tempered by cool sea breezes. This usually mild climatological pattern is interrupted infrequently by periods of extremely hot weather, winter storms, or Santa Ana winds (SCAQMD, 1993).
Data regarding mean annual high and low temperatures at the San Dimas Fire FC 95, California meteorological station (#047749; latitude 34.105°, longitude -117.802°), which is approximately 3.13 miles northeast of the project site, are unavailable (Western Regional Climate Center, 2022). The annual average total precipitation is approximately 18.38 inches, which occurs mostly during the winter and relatively infrequently during the summer.
The SCAB fails to meet national ambient air quality standards for ozone and fine particulate matter, and is classified as a “nonattainment area” for those pollutants (SCAQMD, 2022).
2.3.2 Geology and Soils
The project site is underlain by Monterey Formation shale: white, weathered, thin-bedded, platy, siliceous shale, clay shale, and siltstone (Dibblee, 2002). Calle Cristina extends along a small ridge in the San Jose Hills; land slopes downward to the east and west. Elevations on Calle Cristina onsite are approximately 951 feet above mean sea level (amsl) on the southeast site boundary and 916 feet amsl at the north end of Calle Cristina. Engineering properties of soils, and geologic hazards, are discussed in Section 4.5, Geology and Soils, of this Initial Study.
2.3.3 Hydrology
The project site is in the Walnut Creek watershed, which spans approximately 100 square miles in the northeast San Gabriel Valley and south-central San Gabriel Mountains (USGS, 2017). Part of the north end of the project site is over the San Gabriel Valley Groundwater Basin, which spans approximately 255 square miles in eastern Los Angeles County (DWR, 2022).
2.3.4 Biology
The project site is located in a suburban residential area developed with single family homes. Much of the land surrounding the site is also developed with residential homes and landscaped areas. Many lots include an existing open space easement that has remained natural undeveloped open space.
These areas include intact native habitat areas that were purposefully excluded from the development to retain the rural nature of the site and to serve as refugia for local wildlife. Critical habitat for coastal California gnatcatcher (Polioptila californica) is located to the west/south/east and suitable habitat (coastal sage scrub and chaparral) are suitable for California gnatcatcher and other species. The area also includes California walnut woodland (aka. walnut grove) is sensitive vegetation community. Many of the trees on the site are protected by the city tree ordinance. Most of the drainages throughout the site are considered jurisdictional. A detailed description of existing 7145/San Dimas MCTA 20-0005 Page 2-6
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environmental setting for the project site and the surrounding area is provided in Section 4.4 (Biological Resources) of this Initial Study.
2.3.5 Public Services
The following public services serve the project site:
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Fire and Emergency Medical Service: Los Angeles County Fire Department Law Enforcement: Los Angeles County Sheriff’s Department Schools: Covina-Valley Unified School District
Parks: City of San Dimas Department of Parks and Recreation Library: LA County Library (San Dimas Library)
2.3.6 Utilities
The following public utilities serve the project site:
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•
•
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Electricity: Southern California Edison
Natural Gas: Southern California Gas Company
Telecommunications: Spectrum and Frontier
Water: Golden State Water Company – San Dimas
Sewers: Los Angeles County Consolidated Sewer Maintenance District Wastewater Treatment: Los Angeles County Sanitation District 22 Solid Waste Collection: Waste Management Inc.
Landfills:
o
o
o
El Sobrante Landfill, Corona, Riverside County
Olinda Alpha Landfill, Brea, Orange County
Simi Valley Landfill & Recycling, Simi Valley, Ventura County (CalRecycle, 2022). 7145/San Dimas MCTA 20-0005 Page 2-7
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3.0 PROJECT DESCRIPTION
3.1 Project Location and Existing Conditions
The project site includes Planning Area I within Specific Plan No. 11 (SP-11). SP-11 spans approximately 262 acres west of Via Verde, south of Puente Street and north of Covina Hills Road.
See Figure 3.1-1, Specific Plan No. 11 Location Map.
The approximately 92-acre project site is located in the southwest part of the city of San Dimas. The site is bounded by Covina Hills Road to the south, single-family residential uses and vacant land in the city of Covina and unincorporated Los Angeles County to the west, single-family residences opposite Puente Street to the north, and single-family residences and vacant land to the east. The project site is on and near a hillcrest in the San Jose Hills.
The site is subdivided into 36 residential lots, of which 29 lots are developed with single-family residences and seven are vacant. The project parcels are mapped on Figure 3.1-2, Project Parcel Map.
3.2 Project Overview
The existing San Dimas Municipal Code Chapter 18.518: Specific Plan 11 allows for unlimited grading (cut and fill) for roadway access and excavation to construct retaining foundations for the primary residence and garage. The Municipal Code also allows up to 35% of building lot coverage for the subject residential lots (See Appendix A, Planning Area 1 Lot Coverage Calculations for details) (San Dimas, 2021).
• The average lot size for SP-11, Planning Area 1 is 109,021 square feet (sf) (ranges from 30,371 sf to 932,170 sf).
•
•
The average existing first floor lot coverage is 6.5% (ranges from 0.81% to 14.69%).
The average additional first floor building area for the existing homes is 34,251 sf (ranges from 7,253 sf to 318,718 sf).
• The estimated average available grading to accommodate the additional first floor building area is 21,500 cubic yards (cy) (ranges from 850 cy to over 200,000 cy).
The proposed Municipal Code Text Amendment (MCTA) would allow for up to one thousand (1,000) cubic yards of grading, cut and fill, beyond that grading necessary for the primary residence, driveway and garage for properties located within SP-11 Planning Area 1 (36 residential lots, up to 36,000 CY grading). Per the previous Development Plan Review Board policy, a swimming pool and five (5) feet of decking surrounding the pool were exempted from the additional grading calculations, and will be codified as part of the proposed MCTA. The proposed MCTA would also include development standards for the grading, landscaping and any retaining walls that the additional grading would require. Additional clean-up items are proposed by removing sections which dealt with the initial development of the area and codifying previous policies regarding Conditional Uses within the specific plan.
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Figure 3.1-1
SPECIFIC PLAN NO. 11 LOCATION MAP
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Figure 3.1-2
PROJECT PARCEL MAP
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3.2.1 Proposed Additional Allowable Grading
The project consists of expanding the allowable grading (cut and fill) on each of the 36 residential lots in the project site by 1,000 cubic yards (cy) per lot, increasing the total additional grading by 36,000 cy. The current grading quantity permitted onsite is insufficient for grading backyards, and owners must use decks in the rear portions of their lots. The increase in allowable grading is to permit owners to grade backyards. The increase in allowable grading does not include what is necessary for the primary residence, driveway, and garage and would not expand the allowable lot coverages.
Presently, the Code does not allow grading for a swimming pool and decking; therefore, such grading would be allowed under the proposed additional allowable grading calculations.
The current total grading quantity permitted for the primary residence, driveway, and garage on the 36 lots is approximately 774,000 cy (approximately 21,500 cy per lot); thus, the proposed increase is about 4.7% of the currently permitted grading quantity (City of San Dimas, 2022). Grading permitted under the existing approved Specific Plan is compared to the additional grading under the proposed MCTA in Table 3.2-1 below.
Table 3.2-1
GRADING PERMITTED UNDER EXISTING SPECIFIC PLAN AND PROPOSED AMENDMENTS Existing Specific Plan
Permitted Grading Proposed Additional Grading
Grading Quantity
Purposes
774,000 total cubic yards;
average 21,500 cubic yards per
lot
Mass grading; grading building
pads for primary residences,
garages, and driveways.
36,000 total cubic yards;
1,000 cubic yards per lot
Grading for usable backyards, including
but not limited to swimming pools and
decks; currently decking is only option
for backyard use. Additional grading is
not for primary residences, garages, and
driveways.
Sources: San Dimas, 2022. San Dimas, California Municipal Code Title 18 Zoning, Chapter 18.518 Specific Plan No. 11
3.2.2 Proposed Municipal Code Text Amendments
The proposed project includes the following amendments to San Dimas Municipal Code Chapter
18.518: Specific Plan No. 11 to preserve the original intent of the specific plan, minimize the visual impacts of potential grading and retaining walls, codify existing policies/practices and eliminate defunct sections of the code.
1. Requirements that any proposed grading and retaining walls follow the existing topographic contours present onsite. The proposed grading cuts and/or retaining walls should not cut directly across contour lines.
2. A limitation of retaining walls to a maximum exposed height of 12 feet per wall and a maximum combined exposed height of 24 feet. This language is consistent with existing retaining wall height limit standards used in other hillside areas.
3. A requirement that if more than one retaining wall will be constructed directly adjacent to another, the two walls must be separated by half the height of the taller of the two adjacent walls.
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4. Requirements to use gravity type retaining walls, unless onsite conditions prohibit their use.
5. Wall materials which must be either slump stone or split-face stone with a tan or earth tone color.
6. Landscape and irrigation standards which require the planting of trees at the base of the lowest retaining wall and drought-tolerant shrubs at the base of every wall. Installation of permanent irrigation shall be required to ensure that the required landscaping survives and is healthy enough to provide screening.
3.2.3 Project Operation
Project implementation would not change operation of existing and future residences onsite. Land use of the project site would not change.
3.3 Discretionary and Ministerial Approvals
Project approval requires approval of the proposed MCTA by the City of San Dimas.
Implementation of the proposed project on each residential lot would require approval of a grading permit—by the City of San Dimas Building & Safety Division. Existing required submittals and approvals would not change.
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❖ SECTION 4.0 – ENVIRONMENTAL CHECKLIST ❖
Evaluation of Environmental Impacts
(1) A brief explanation is required for all answers except “No Impact” answers that are adequately supported by the information sources a lead agency cites in the parentheses following each question. A “No Impact” answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved (e.g., the project falls outside a fault rupture zone). A “No Impact” answer should be explained where it is based on project-specific factors, as well as general standards (e.g., the project would not expose sensitive receptors to pollutants, based on a project-specific screening analysis).
(2) All answers must take into account the whole action involved, including offsite as well as onsite, cumulative as well as project-level, indirect as well as direct, and construction as well as operational impacts.
(3) Once the lead agency has determined that a particular physical impact may occur then the checklist answers must indicate whether the impact is potentially significant, less than significant with mitigation, or less than significant. “Potentially Significant Impact” is appropriate if there is substantial evidence that an effect may be significant. If there are one or more “Potentially Significant Impact” entries when the determination is made, an EIR is required.
(4) “Negative Declaration: Less than Significant with Mitigation Incorporated” applies where the incorporation of mitigation measures has reduced an effect from “Potentially Significant Impact” to a “Less than Significant Impact.” The lead agency must describe the mitigation measures and briefly explain how they reduce the effect to less than significant level. (5) Earlier analyses may be use where, pursuant to the tiering, Program EIR, or other CEQA process, an affect has been adequately analyzed in an earlier EIR or negative declaration. (See Section 15063(c)(3)(D) of the CEQA Guidelines. In this case, a brief discussion should identify the following:
(a) Earlier Analyses Used. Identify and state where the earlier analysis available for review.
(b) Impacts Adequately Addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis.
(c) Mitigation Measures. For effects that are “Less than Significant with Mitigation Measures Incorporated,” describe the mitigation measures that were incorporated or refined from the earlier document and the extent to which they address site-specific conditions for the project.
(6) Lead agencies are encouraged to incorporate into the checklist references to information sources for potential impacts (e.g., general plans, zoning ordinances). Reference to a previously prepared or outside document should, where appropriate, include a reference to the page or pages where the statement is substantiated. A source list should be attached and other sources used or individuals contacted should be cited in the discussion. 7145/San Dimas MCTA 20-0005 Page 4-2
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(7) Supporting Information Sources: A source list should be attached, and other sources used or individuals contacted should be cited in the discussion. (8) This is only a suggested form, and lead agencies are free to use different formats; however, lead agencies should normally address the questions from this checklist that are relevant to a project’s environmental effects in whatever format is selected. (9) The explanation of each issue should identify:
(a) The significance criteria or threshold, if any, used to evaluate each question; and (b) The mitigation measure identified, if any, to reduce the impact to less than significant.
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4.1 Aesthetics
Less than
Except as provided in Public
Resources Code Section 21099, would
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact the project:
Incorporated
a) Have a substantial adverse effect on a
scenic vista? X
X
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
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 which would adversely
affect day or nighttime views in the
area?
X
X
“Visual environment” includes the built environment (development patterns, buildings, parking areas, and circulation elements) and natural environment features such as hills, vegetation, rock outcroppings, drainage pathways, and soils.
Views are characterized by visual quality, viewer groups and sensitivity, duration, and visual resources.
• Visual quality refers to the general aesthetic quality of a view, such as vividness, intactness, and unity.
•
•
Viewer groups identify who is most likely to experience the view.
High-sensitivity land uses include residences, schools, playgrounds, religious institutions, and passive outdoor spaces such as parks, playgrounds, and recreation areas. •
•
Duration of a view is the amount of time that a particular view can be seen by a specific viewer group.
Visual resources refer to unique views, and views identified in local plans, from scenic highways, or of specific unique structures or landscape features. 7145/San Dimas MCTA 20-0005 Page 4.1-1
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a) Except as provided in Public Resources Code Section 21099 would the project have a substantial adverse effect on a scenic vista?
Less Than Significant Impact
Scenic vistas generally include extensive panoramic views of natural features, unusual terrain, or unique urban or historic features, for which the field of view can be wide and extend into the distance, and focal views that focus on a particular object, scene or feature of interest.
The City of San Dimas General Plan does not have any classified scenic vistas. However, the city contains scenic resources such as open foothills and canyons, the San Gabriel Mountains, Way Hill, San Dimas Canyon, Sycamore Canyon, Walnut Creek, and Cinnamon Creek that serve as unique visual resources that the city would like to preserve (City of San Dimas, 1991, p. V-18). In addition, the City has classified Puente Street, which runs generally in an east/west direction, to the north (and below the elevation) of the site, as a scenic highway corridor (City of San Dimas, 1991, p. V-28); views of the project from Puente Street are mostly blocked by intervening topography and vegetation.
The project site is located within an urban portion of the City of San Dimas surrounded with singlefamily homes to the north and west, and single-family homes and undeveloped land to the south and east. Dominant natural visual resources in the vicinity of the project site include the San Gabriel Mountains, foothills, and canyons and views from surrounding areas towards the project site are characterized primarily by vegetated terrain, including trees in many areas (Google Earth Pro, 2022).
Figure 2.2-2 provides photographs from Calle Cristina, the primary spine street within the project area. Figure 4.1-1 depicts a photo location map for the photos shown in Figures 4.1-2 through 4.1-
4. The proposed project would incorporate a Municipal Code Text Amendment (MCTA) allowing for additional grading within the project site, which would include development standards for the grading, landscaping and any retaining walls that the additional grading would require. The purpose of the MCTA is to allow homeowners within the project site to create an adequate backyard space that is leveled. With current regulations, homeowners could only install a deck with supporting beams due to the steep nature of their backyards and grading limits. The proposed project would not expand beyond the current property boundaries and would only deepen residential backyards, which would benefit viewing of the surrounding scenic resources from within the project area and at the same time would have minimal impact on views into the project from the surrounding area.
Therefore, the proposed project would create less than significant impacts in regards to scenic vistas. b) Except as provided in Public Resources Code Section 21099, would the project substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway? Less Than Significant Impact
The California Department of Transportation (Caltrans) provides information regarding officially designated or eligible state scenic highways, designated as part of the California Scenic Highway Program. According to Caltrans, there are no officially designated scenic highways within or adjacent to the project area, and no roadways near the project site are currently eligible for scenic highway designation (Caltrans, 2022), as shown in Figure 4.1-5, Scenic Highways. In addition, in its General Plan Open Space Element (City of San Dimas, 1991, p. V-28) the City has classified Puente Street as a scenic highway corridor.
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Figure 4.1-1
PHOTO LOCATION MAP
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Figure 4.1-2
PHOTOS OF THE SURROUNDING PROJECT AREA (1-4)
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Figure 4.1-3
PHOTOS OF THE SURROUNDING PROJECT AREA (5-8)
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Figure 4.1-4
PHOTOS OF THE SURROUNDING PROJECT AREA (9-12)
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Figure 4.1-5
SCENIC HIGHWAYS
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The closest official state scenic highway, State Route 91 (SR-91), is approximately 15 miles south of the project site. The city considers the 210 Foothill Freeway and Highway 30 to be regional scenic highways, and Walnut Avenue, Puente Street and San Dimas Avenue to be local scenic highways (City of San Dimas, 1991, p. V-19). However, none of the regional or state scenic highways are within at least three miles from the project site (most are far more distant), nor is any of them visible from the project, and the view from Puente Street is mostly blocked by intervening topography and vegetation as seen in Figures 4.1-3 and 4.1-4. Therefore, the project would have no impacts on trees, rock outcroppings and historic buildings within a state scenic highway, and at most a less than significant impact on scenic views from locally- and regionally-designated scenic highways. c) Except as provided in Public Resources Code Section 21099, would the project 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 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?
Less than Significant Impact
The project site is located in an urban setting characterized by very low-density single-family residential land uses, and thus subject to applicable zoning and other regulations governing scenic quality. Table 4.1-1 below provides the applicable policies from the City of San Dimas General Plan that pertain to aesthetics, along with a description of how the proposed project would be in compliance.
Table 4.1-1
PROJECT COMPLIANCE WITH CITY OF SAN DIMAS GENERAL PLAN POLICIES REGARDING
SCENIC QUALITY AND AESTHETICS
General Plan Element
Open Space Element
Project Compliance
Goal OS-1: Maintain the rural open space atmosphere.
Objectives The proposed project would allow homeowners within
1.1 Continue to enhance the “western theme”, the project site to further grade their backyards to “Early California theme”, and Frontier create a more adequate backyard without the need of Village themes within the City. support structures. The project would not affect the design theme of the City and would continue to retain
Policies: the low-density atmosphere. Therefore, the project
1.1.1 Retain the low-density atmosphere of San would not conflict with this goal.
Dimas
Open Space Element
Goal OS-4: Preserve San Dimas’ scenic resources.
Objectives
4.1 Preserve existing views of the foothills.
The proposed project would allow homeowners to
increase the amount of grading in their backyard, which
4.2 Enhance the scenic highways within the would allow them to level-out the elevation of a portion City. of their backyards to be able to have a patio adjacent to the back of their homes. This would not include any
buildings. Existing views from Puente Street would not
be hindered since it is a lower elevation that the project Policies:
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General Plan Element Project Compliance
4.1.1 Minimize views to development from site. Therefore, the project would not conflict with this trails within the natural areas and view goal.
corridors.
Open Space Element
Goal OS-5: Preserve the city’s northern foothills.
Objectives
5.1 Preserve existing ridge lines.
The proposed project would allow homeowners to
increase the amount of grading in their backyard, which
5.2 Preserve the topographic and scenic would allow them to level-out the elevation of a portion character of the northern foothills. of their backyards. Views from areas surrounding the proposed site would not be impeded or degraded.
Policies: Therefore, the project would not conflict with this goal.
5.1.1 Development shall conform to terrain.
5.1.2 Protect views and viewsheds of the
foothills.
Conservation Element
Goal CN-4: Preserve San Dimas’ northern foothills.
Objectives The proposed project would allow homeowners to
4.1 Conserve the integrity of the northern increase the amount of grading in their backyards, foothills and maintain a reasonable economic which would allow them to level-out the area behind return for the landowner. their homes for a patio. The project would not extend beyond the existing homeowner’s property lines and
Policies: would maintain the very low-density residential land
4.1.1 Designate the northern foothills as very use. Therefore, the project would not conflict with this low-density residential development to goal.
minimize grading and protect its natural
appearance.
Conservation Element
Goal CN-6: Conserve Puddingstone Hills
Objectives The project is not located within Puddingstone Hills.
6.1 Conserve the integrity of the Puddingstone Therefore, the project would not conflict with this goal.
Hills and maintain a reasonable economic
return for the landowner.
Policies:
4.1.1 Designate the Puddingstone Hills as very
low-density residential development to
minimize grading and protect its natural
appearance.
Source: City of San Dimas, 1991, p. V-21 through V-23, and VI-21 through V-22 The proposed MCTA requires that retaining walls be constructed during the grading process provided for in the MCTA. As analyzed above, the proposed project would adhere to applicable aesthetic and scenic quality regulations and policies mandated by the City of San Dimas General Plan.
The proposed project would allow homeowners to create an adequately spaced backyard when compared to existing conditions. Additionally, the proposed project would adhere to Chapter 18.518, Specific Plan No. 11 in the City’s Municipal Code, which would ensure that building height, setbacks, 7145/San Dimas MCTA 20-0005 Page 4.1-3
Initial Study/Mitigated Negative Declaration Page 1019 – 2053 December 2022 ❖ SECTION 4.1 - AESTHETICS ❖
building design, parking stalls and screening would be within required threshold levels (City of San Dimas, 2021a). Therefore, the proposed project would have less than significant impacts. d) Except as provided in Public Resources Code Section 21099, would the project create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?
Less Than Significant Impact
The project site is located in an urban area, which is characterized by low to medium nighttime ambient light levels. Street lights, traffic on local streets and exterior lighting in nearby developments are the primary sources of light that contribute to the ambient light levels in the project area. The project is generally surrounded by residential land uses and/or open space in all directions (Google Earth Pro, 2022).
The project proposes an MCTA that would allow residential owners within the project site to increase the amount of grading allowed in their backyards. The project does not introduce new lighting; however, grading activities could introduce temporary lighting in the area. All lighting would adhere to the City of San Dimas Municipal Code § 18.518.280, which would ensure that lighting and glare would cause less than significant impacts (City of San Dimas Municipal Code, 2021a). Therefore, with adherence to the city’s Municipal Code, the proposed project would have less than significant impacts in regard to light and glare, and no mitigation is required. 7145/San Dimas MCTA 20-0005 Page 4.1-4
Initial Study/Mitigated Negative Declaration Page 1020 – 2053 December 2022 ❖ SECTION 4.2 - AGRICULTURE AND FORESTRY RESOURCES ❖
4.2 Agriculture and Forestry Resources
Less than
Significant
Impact with
Mitigation
Potentially
Significant
Impact
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
a) Convert Prime Farmland, Unique
Farmland, or Farmland of Statewide
Importance (Farmland), as shown on
the maps prepared pursuant to the
Farmland Mapping and Monitoring
Program of the California Resources
Agency, to non-agricultural use?
b) Conflict with existing zoning for
agricultural use, or a Williamson Act
contract?
X
X
c) Conflict with existing zoning for, or
cause rezoning of, forest land (as
defined in Public Resources Code
§ 12220(g)), timberland (as defined
by Public Resources Codes § 4526),
or timberland zoned Timberland
Production (as defined by
X
Government Code § 51104(g))?
d) Result in the loss of forest land or
conversion of forest land to nonforest use?
e) Involve other changes in the existing
environment which, due to their
location or nature, could result in
conversion of Farmland, to nonagricultural use or conversion of forest land to non-forest use?
X
X
a) Would the project convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use?
No Impact
The California Department of Conservation (DOC) established the Farmland Mapping and Monitoring Program (FMMP) in 1982 to identify critical agricultural lands and track the conversion of these lands to other uses. The FMMP is a non-regulatory program and provides a consistent and impartial analysis of agricultural land use and land use changes throughout California. As depicted in Figure 4.2-1 below, the project site and surrounding uses are designated by the FMMP as “Urban and Built-Up Land,” and “Other Land” which means that no agricultural uses were mapped onsite (DOC, 2022a). The project is located within a generally urbanized area, and construction activities and onsite improvements would occur within the project site. Therefore, no farmland would be converted to non-agricultural use and no impacts would occur. 7145/San Dimas MCTA 20-0005 Page 4.2-1
Initial Study/Mitigated Negative Declaration Page 1021 – 2053 December 2022 ❖ SECTION 4.2 - AGRICULTURE AND FORESTRY RESOURCES ❖
Figure 4.2-1
IMPORTANT FARMLAND
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.2 - AGRICULTURE AND FORESTRY RESOURCES ❖
b) Would the project conflict with existing zoning for agricultural use, or a Williamson Act contract?
No Impact
The Williamson Act allows local governments to work with private landowners by negotiating an agreement to tax these landowners at lower rates if they restrict specific pieces of land to agricultural or open space use. Refer to Figure 4.2-2, which depicts the project location relative to the location of Williamson Act Lands in Southern California. The project site area has a City of San Dimas Zoning Designation of Specific Plan (SP) (City of San Dimas, 1991). Therefore, the project would not conflict with existing zoning for agricultural use or a Williamson Act contract and no impact would occur. c) Would the project conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code § 12220(g)), timberland (as defined by Public Resources Codes § 4526), or timberland zoned Timberland Production (as defined by Government Code § 51104(g))?
No Impact
The project site is zoned as Specific Plan (City of San Dimas, 2021) and is not zoned for forest land, timberland, or timberland production Therefore, proposed project would not conflict with zoning for forest land or timberland, and no impact would occur.
d) Would the project result in the loss of forest land or conversion of forest land to non-forest use?
No Impact
No forest land is present on or next to the project site. Therefore, development activity in the proposed project area would not cause the loss of forest land or conversion of forest land to non-forest use, and no impact would occur.
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 Impact
The project site and surrounding properties are not currently used for agriculture and are developed in a mostly urbanized setting. Therefore, project development would not involve other changes in the existing environment which, due to their location or nature, could cause conversion of Farmland, to non-agricultural use or conversion of forest land to non-forest use. No impacts would occur. 7145/San Dimas MCTA 20-0005 Page 4.2-3
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Figure 4.2-2
WILLIAMSON ACT LANDS
7145/San Dimas MCTA 20-0005 Page 4.2-4
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4.3 Air Quality
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
a) Conflict with or obstruct
implementation of the applicable air
quality plan?
X
X
b) Result in a cumulatively considerable
net increase of any criteria pollutant
for which the project region is nonattainment under an applicable federal or state ambient air quality standard?
c) Expose sensitive receptors to X
X
substantial pollutant concentrations?
d) Result in other emissions (such as
those leading to odors adversely
affecting a substantial number of
people?
4.3.1 Pollutants of Concern
Criteria pollutants are air pollutants for which acceptable levels of exposure can be determined and ambient air quality standards have been established by the U.S. Environmental Protection Agency (USEPA) and/or the California Air Resources Board (ARB). The criteria air pollutants of concern are nitrogen dioxide (NO ), carbon dioxide (CO ), particulate matter (PM and PM 2 2 10 2.5), sulfur dioxide (SO ), lead (Pb), and ozone (O ), and their precursors, such as reactive organic gases (ROG), which 2 3 are ozone precursors. Since the proposed project would not generate appreciable SO2 or Pb emissions,5 it is not necessary for the analysis to include those two pollutants. Presented below is a description of the air pollutants of concern and their known health effects.
Nitrogen oxides (NOX) serve as integral participants in the process of photochemical smog production and are precursors for certain particulate compounds that are formed in the atmosphere.
The two major forms of NO are nitric oxide (NO) and NO . NO is a colorless, odorless gas formed from x 2 atmospheric nitrogen and oxygen when combustion takes place under high temperature and/or high pressure. NO is a reddish-brown pungent gas formed by the combination of NO and oxygen. NO is 2 2 an acute respiratory irritant and eye irritant and increases susceptibility to respiratory pathogens. A third form of NO , nitrous oxide (N O), is a greenhouse gas (GHG) (USEPA, 2022f). X 2 Carbon monoxide (CO) is a colorless, odorless non-reactive pollutant produced by incomplete combustion of carbon substances (e.g., gasoline or diesel fuel). The primary adverse health effect associated with CO is its binding with hemoglobin in red blood cells, which decreases the ability of these cells to transport oxygen throughout the body. Prolonged exposure can cause headaches, drowsiness, or loss of equilibrium; high concentrations are lethal (USEPA, 2022g). 5 Sulfur dioxide emissions will be below 0.081 pound per day during construction. 7145/San Dimas MCTA 20-0005 Page 4.3-1
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Particulate matter (PM) consists of finely divided solids or liquids, such as soot, dust, aerosols, fumes, and mists. Two forms of fine particulate matter are now regulated. Respirable particles, or PM10, include that portion of the particulate matter with an aerodynamic diameter of 10 micrometers (i.e., 10 one-millionths of a meter or 0.0004 inch) or less. Fine particles, or PM2.5, have an aerodynamic diameter of 2.5 micrometers (i.e., 2.5 one-millionths of a meter or 0.0001 inch) or less. Particulate discharge into the atmosphere results primarily from industrial, agricultural, construction, and transportation activities. However, wind action on the arid landscape also contributes substantially to the local particulate loading. Fossil fuel combustion accounts for a sizable portion of PM2.5. In addition, particulate matter forms in the atmosphere through reactions of NOX and other compounds (such as ammonia) to form inorganic nitrates and sulfates. Both PM10 and PM2.5 may adversely affect the human respiratory system, especially in those people who are naturally sensitive or susceptible to breathing problems (USEPA, 2022h).
Reactive organic gases (ROG) are compounds comprised primarily of atoms of hydrogen and carbon that have high photochemical reactivity. The major source of ROG is the incomplete combustion of fossil fuels in internal combustion engines. Other sources of ROG include the evaporative emissions associated with the use of paints and solvents, the application of asphalt paving and the use of household consumer products. Some ROG species are listed toxic air contaminants, which have been shown to cause adverse health effects; however, most adverse effects on human health are not caused directly by ROG, but rather by reactions of ROG to form other criteria pollutants such as ozone. ROG are also transformed into organic aerosols in the atmosphere, contributing to higher levels of fine particulate matter and lower visibility. The term “ROG” is used by the ARB for air quality analysis and is defined essentially the same as the federal term “volatile organic compound” (VOC).6 Ozone (O3) is a secondary pollutant produced through a series of photochemical reactions involving ROG and NO . Ozone creation requires ROG and NO to be available for approximately three hours in X x a stable atmosphere with strong sunlight. Because of the long reaction time, peak ozone concentrations frequently occur downwind of the sites where the precursor pollutants are emitted.
Thus, O is considered a regional, rather than a local, pollutant. The health effects of O include eye 3 3 and respiratory irritation, reduction of resistance to lung infection and possible aggravation of pulmonary conditions in persons with lung disease. Ozone is also damaging to vegetation and untreated rubber (USEPA, 2022i).
4.3.2 Climate/Meteorology
The project site will be located wholly within the South Coast Air Basin SCAB, which includes all of Orange County, as well as the non-desert portions of Los Angeles, Riverside, and San Bernardino Counties. The distinctive climate of the SCAB is determined by its terrain and geographical location.
The SCAB is in a coastal plain with connecting broad valleys and low hills, bounded by the Pacific Ocean in the southwest quadrant with high mountains forming the remainder of the perimeter. The general region lies in the semi-permanent high-pressure zone of the eastern Pacific. Thus, the climate is mild, tempered by cool sea breezes. This usually mild climatological pattern is interrupted infrequently by periods of extremely hot weather, winter storms, or Santa Ana winds (SCAQMD, 1993).
6 Emissions of organic gases are typically reported only as aggregate organics, either as VOC or as ROG. These terms are meant to reflect what specific compounds have been included or excluded from the aggregate estimate. Although EPA defines VOC to exclude both methane and ethane, and the ARB defines ROG to exclude only methane, in practice it is assumed that VOC and ROG are essentially synonymous.
7145/San Dimas MCTA 20-0005 Page 4.3-2
Initial Study/Mitigated Negative Declaration Page 1026 – 2053 December 2022 ❖ SECTION 4.3 – AIR QUALITY ❖
The annual average of total precipitation at the San Dimas Fire FC 95 meteorological station (#047749; latitude 34.105°, longitude -117.802°) (WRCC, 2022a), which is approximately 3.13 miles northeast of the project site, is approximately 18.38 inches, which occurs mostly during the winter and relatively infrequently during the summer. Monthly precipitation averages approximately 4.12 inches during the winter (December, January, and February), approximately 1.53 inches during the spring (March, April, and May), approximately 0.88 inch during the fall (September, October, and November), and approximately 0.063 inch during the summer (June, July, and August). The average high and low temperatures as recorded at Pomona Fairplex meteorological station (#047050; latitude 34.04°, longitude -117.46°) (WRCC, 2022b), which is approximately 4.22 miles east of the project site, are 77.5°F and 47.6°F, respectively. Average winter (December, January, and February) high and low temperatures are approximately 66.5°F and 38.93°F and average summer (June, July, and August) high and low temperatures are approximately 88.73°F and 56.4°F.
4.3.3 Local Air Quality
Table 4.3-1 shows the area designation status of the SCAB for each criteria pollutant for both the National Ambient Air Quality Standards (NAAQS) and the California Ambient Air Quality Standards (CAAQS).
The South Coast Air Quality Management District (SCAQMD) has divided the SCAB into source receptor areas (SRAs), based on similar meteorological and topographical features. The proposed project site is in SCAQMD’s Pomona-Walnut Valley SRA (SRA 10), which is served by the Glendora Station, located about five miles north of the proposed project site, at 840 Laurel Avenue, Glendora CA 91741 (SCAQMD, 2022). All the criteria pollutants discussed in this report are monitored at this station. The ambient air quality data in the proposed project vicinity as recorded at the Glendora station from 2018 to 2020 and the applicable federal and state standards are shown in Table 4.3-2.
Table 4.3-1
FEDERAL AND STATE ATTAINMENT STATUS
Pollutants Federal Classification
Nonattainment (Extreme)
Maintenance (Serious)
Nonattainment (Serious)
Maintenance (Serious)
Maintenance
State Classification
Ozone (O3) Nonattainment
Particulate Matter (PM10)
Fine Particulate Matter (PM2.5
Carbon Monoxide (CO)
Nitrogen Dioxide (NO2)
Sulfur Dioxide (SO2)
Sulfates
Nonattainment
Nonattainment
Attainment
Attainment
Attainment
Attainment
Attainment
Attainment
Unclassified
)
Attainment
Lead (Pb)
No Federal Standards
Hydrogen Sulfide (H2S)
Visibility Reducing Particles
Sources: ARB, USEPA
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.3 – AIR QUALITY ❖
Table 4.3-2
AMBIENT AIR QUALITY MONITORING DATA
Air
Pollutant
Standard/Exceedance 2018 2019 2020
Max. 1-hour Concentration (ppm)
Max. 8-hour Concentration (ppm)
# Days > Federal 8-hour Std. of 0.070 ppm
# Days > California 1-hour Std. of 0.070 ppm
# Days > California 8-hour Std. of 0.070 ppm
Max. 1-hour Concentration (ppm)
Annual Average (ppm)
# Days > California 1-hour Std. of 0.070 ppm
Federal Max. 24-hour Concentration (µg/m3)
State Max. 24-hour Concentration (µg/m3)
#Days > Fed. 24-hour Std. of 35 µg/m3 State
Annual
0.14 0.105
46 32
46 0.06
0.009
0 101.7
ND
0.13 0.103
58 46
61 0.06
0.008
0 97.9
ND
0.173
0.138
Ozone (O3) 97
76 100
0.05 0.008
0 227.2
ND
Nitrogen
Dioxide
(NO2)
Respirable
Particulate
Matter (PM10)
0 ND 2
Federal Average (µg/m3)
State Average (µg/m3)
28.6 ND
21.8 ND
28 ND
Federal Max. 24-hour Concentration (µg/m3)
State Max. 24-hour Concentration (µg/m3)
#Days > Fed. 24-hour Std. of 35 µg/m3 State
Annual
ND
84.8 ND
75.1 ND
Fine 148.1
Particulate
Matter ND ND ND
(PM2.5) Federal Average (µg/m3)
State Average (µg/m3)
ND
ND
ND
11.7 ND
14.9 Source: California Air Resources Board, “iADAM Air Quality Data Statistics.” Internet URL:
http://www.arb.ca.gov/adam/, (April, 2022).
ND - There was insufficient (or no) data available to determine the value.
4.3.4 Air Quality Management Plan (AQMP)
The SCAQMD is required to produce plans to show how air quality will be improved in the region.
The California Clean Air Act (CCAA) requires that these plans be updated triennially to incorporate the most recent available technical information. A multi-level partnership of governmental agencies at the federal, state, regional, and local levels implement the programs contained in these plans.
Agencies involved include the EPA, ARB, local governments, SCAG, and SCAQMD. The SCAQMD and the SCAG are responsible for formulating and implementing the AQMP for the SCAB. The SCAQMD updates its Air Quality Management Plan (AQMP) every three years.
The 2016 AQMP (SCAQMD, 2017b) was adopted by the SCAQMD Board on March 3, 2017, and on March 10, 2017 was submitted to the ARB (SCAQMD, 2017a) to become part of the State Implementation Plan (SIP)7 (SCAQMD, 2017a). It focuses largely on reducing NOx emissions as a means of attaining the 1979 1-hour ozone standard by 2022, the 1997 8-hour ozone standard by 2023, and the 2008 8-hour standard by 2031 (SCAQMD, 2017b). The AQMP prescribes a variety of current and proposed new control measures, including a request to the EPA for increased regulation 7 The State Implementation Plan (SIP) is a collection of local and regional plans, regulations, and rules for attaining ambient air quality standards. It is periodically submitted to the USEPA for approval. 7145/San Dimas MCTA 20-0005 Page 4.3-4
Initial Study/Mitigated Negative Declaration Page 1028 – 2053 December 2022 ❖ SECTION 4.3 – AIR QUALITY ❖
of mobile source emissions. The NOx control measures will also help the SCAB attain the 24-hour standard for PM2.5.
4.3.5 Sensitive Receptors
Some people, such as individuals with respiratory illnesses or impaired lung function because of other illnesses, persons over 65 years of age, and children under 14, are particularly sensitive to certain pollutants. Facilities and structures where these sensitive people live or spend considerable amounts of time are known as sensitive receptors. For the purposes of a CEQA analysis, the SCAQMD considers a sensitive receptor to be a receptor such as a residence, hospital, or convalescent facility where it is possible that an individual could remain for 24 hours (Chico and Koizumi, 2008, p. 3-2).
Commercial and industrial facilities are not included in the definition of sensitive receptor, because employees typically are present for shorter periods of time, such as eight hours. Therefore, applying a 24-hour standard for PM10 is appropriate not only because the averaging period for the state standard is 24 hours, but because the sensitive receptor would be present at the location for the full 24 hours.
4.3.6 a)
Analysis of Impacts
Would the project conflict with or obstruct implementation of the applicable air quality plan?
Less than Significant Impact
The SCAQMD (2019) has developed criteria in the form of emissions thresholds for determining whether emissions from a project are regionally significant. They are useful for estimating whether a project is likely to result in a violation of the NAAQS and/or whether the project is in conformity with plans to achieve attainment. SCAQMD’s significance thresholds for criteria pollutant emissions during construction activities are summarized in Table 4.3-3. A project is considered to have a regional air quality impact if emissions from its construction activities exceed the corresponding SCAQMD significance thresholds.
Table 4.3-3
SCAQMD EMISSIONS THRESHOLDS FOR SIGNIFICANT REGIONAL IMPACTS Mass Daily
Thresholds
(Pounds/Day) for
Construction
Pollutant
Nitrogen Oxides (NOx) 100
Volatile Organic Compounds (VOC) 75
Respirable Particulate Matter (PM10)
Fine Particulate Matter (PM2.5)
Sulfur Oxides (SOX)
150
55 150
550
3 Carbon Monoxide (CO)
Lead
Source: SCAQMD, 2019.
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.3 – AIR QUALITY ❖
Air Quality Methodology
Estimated criteria pollutant emissions from the project’s onsite and offsite project activities were calculated using the California Emissions Estimator Model (CalEEMod), Version 2020.4.0. CalEEMod (CAPCOA, 2021) is a planning tool for estimating emissions related to land use projects.
Model-predicted project emissions are compared with applicable thresholds to assess regional air quality impacts. As some construction plans have not been finalized, CalEEMod defaults were used for construction offroad equipment and onroad construction trips and vehicle miles traveled.
For the purpose of this analysis, construction activities for the San Dimas MCTA 20-0005 Project are anticipated to last seven months and would begin in early January 2023 and end in August 2023.
There would be only one construction phase of grading activities. This construction schedule is also used for calculating GHG emissions presented in Section 4.8 and for the noise analyses in Section
4.13. The construction activity would temporarily create emissions of dusts, fumes, equipment exhaust, and other air contaminants. Mobile sources (such as diesel-fueled equipment onsite and traveling to and from the project site) would primarily generate NOX emissions. The amount of emissions generated daily would vary, depending on the amount and types of construction activities occurring at the same time.
Regional Short-Term Air Quality Effects
Project construction activities would generate short-term air quality impacts. Construction emissions can be distinguished as either onsite or offsite. Onsite air pollutant emissions consist principally of exhaust emissions from offroad heavy-duty construction equipment, as well as fugitive particulate matter from earth working and material handling operations. Offsite emissions result from workers commuting to and from the job site, as well as from trucks hauling materials to the site and construction debris for disposal.
As shown in Table 4.3-5, construction emissions would not exceed SCAQMD regional thresholds.
Therefore, the project’s short-term regional air quality impacts would be less than significant.
Table 4.3-5
MAXIMUM DAILY REGIONAL CONSTRUCTION EMISSIONS
Maximum Emissions (pounds/day)
Construction Activity
ROG NOx CO PM10 PM2.5
Maximum Emissions, 2023 3.45 38.35 29.79 11.41 5.19
SCAQMD Significance Thresholds 75 100 550 150 55
Significant? (Yes or No) No No No No No
Source: Calculated by OB-1 Air Analyses with CalEEMod (Version 2020.4.0 (CAPCOA, 2021).
Regional Long-Term Air Quality Effects
Operational emissions were not addressed in this study, because the only activity that will change is the grading of additional land. Thus, the long-term air quality impacts were not evaluated. 7145/San Dimas MCTA 20-0005 Page 4.3-6
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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?
Less than Significant Impact
Since the SCAB is currently in nonattainment for ozone and PM2.5, related projects may exceed an air quality standard or contribute to an existing or projected air quality exceedance. The SCAQMD neither recommends quantified analyses of construction emissions from multiple development projects nor provides methodologies or thresholds of significance to be used to assess the cumulative emissions generated by multiple cumulative projects. Instead, the District recommends that a project’s potential contribution to cumulative impacts be assessed utilizing the same significance criteria as those for project-specific impacts. Furthermore, the SCAQMD states that if an individual development project generates less-than-significant construction emissions impacts, the development project would not contribute to a cumulatively considerable increase in emissions for those pollutants for which the Basin is in nonattainment.
As discussed above, the mass daily construction emissions generated by the project would not exceed any of the SCAQMD’s significance thresholds. Also, as discussed below, localized emissions generated by the project would not exceed the SCAQMD’s Localized Significance Thresholds (LSTs). Therefore, the project would not contribute a cumulatively considerable increase in emissions for the pollutants which the Basin is in nonattainment. Thus, cumulative air quality impacts associated with the project would be less than significant.
c) Would the project expose sensitive receptors to substantial pollutant concentrations? Less than Significant Impact
Localized Short-Term Air Quality Effects from Construction Activity Construction of the proposed project would generate short-term and intermittent emissions.
Following SCAQMD guidance (Chico and Koizumi, 2008), only onsite construction emissions were considered in the localized significance analysis. The residences in the project site, are the nearest sensitive receptors. Localized significance thresholds for projects in SRA 10 were obtained from tables in Appendix C of the SCAQMD’s Final Localized Significance Threshold Methodology (Chico and Koizumi, 2008). Table 4.3-7 shows the results of the localized significance analysis for the proposed project. The localized significance analysis determined that the project would not expose sensitive receptors to substantial pollutant concentrations. Therefore, impacts would be less than significant.
Screening Health Risk Assessment
Given that the proposed project will not be an important source of toxic air contaminants, and will not be a receptor for significant TAC emissions from offsite sources, impacts from TACs will be less than significant
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Table 4.3-7
RESULTS OF LOCALIZED SIGNIFICANCE ANALYSIS
Maximum Onsite Emissions (pounds/day)
Nearest Sensitive Receptor
NOx CO PM10 PM2.5
Maximum daily unmitigated emissions
SCAQMD LST for 5 acres @ 25 metersa
Significant (Yes or No)
34.52 236
28.05 1,566
No
5.58 12
2.96 7
No No No
aLST values were from SCAQMD table values corresponding to 25 meters (Chico and Koizumi, 2008, Appendix C) d) Would the project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
Less than Significant Impact
Odors can cause a variety of responses. The impact of an odor results from interacting factors such as frequency (how often), intensity (strength), duration (in time), offensiveness (unpleasantness), location, and sensory perception.
Under this significance criterion, a significant impact is defined here as a situation in which a project creates an odor nuisance pursuant to SCAQMD Rule 402 (Nuisance). Rule 402 broadly defines nuisance odors; in reality, it is imposed only in cases in which (1) complaints are received by the SCAQMD, and (2) an inspector personally observes the offensive odor. Because the proposed project site is in a residential area, and unusually odorous materials will not be handled, Rule 402 complaints are unlikely.
Land uses typically considered associated with odors include wastewater treatment facilities, waste disposal facilities, or agricultural operations. The proposed project is not a land use typically associated with emitting objectionable odors. It would involve the use of diesel construction equipment and diesel trucks during construction. In addition, project-generated emissions would rapidly disperse in the atmosphere and would not be noticeable to the nearby public. Therefore, the project would not generate a significant odor impact during construction. 7145/San Dimas MCTA 20-0005 Page 4.3-8
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4.4 Biological Resources
Less than
Potentially
Significant
Impact
Significant Less than
Significant
Impact
No
Impact Would the project: with
Mitigation
Incorporated
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?
X
b) Have a substantial adverse effect on any
riparian habitat or other sensitive
natural community identified in local or
regional plans, policies, regulations or
by the California Department of Fish and
Wildlife or U.S. Fish and Wildlife
Service?
X
X
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 nursery sites?
X
X
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?
X
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Initial Study/Mitigated Negative Declaration Page 1033 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
4.4.1 Methodology
UltraSystems biologists researched readily available information, including relevant literature, databases, agency websites, various previously completed reports and management plans, GIS data, maps, aerial imagery from public domain sources, and in-house records to identify the following: 1) habitats, special-status plant and wildlife species, jurisdictional waters, critical habitats, and wildlife corridors that may occur in and near the project site; and 2) local or regional plans, policies, and regulations that may apply to the project. The following data sources were accessed by UltraSystems for synthesis of data within this Initial Study.
•
•
•
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United States Geological Survey (USGS) 7.5-Minute Topographic Map San Dimas Quadrangle and current aerial imagery (USGS, 2018).
The Web Soil Survey, provided by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) (USDA NRCS, 2021).
California Interagency Wildlife Task Group. CWHR version 9.0 personal computer program, provided by CDFW (CDFW, 2014)
California Natural Diversity Database (CNDDB), provided by the California Department of Fish and Wildlife (CDFW) (CNDDB, 2022a).
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California Department of Fish and Wildlife BIOS Habitat Connectivity Viewer (CDFW, 2022a) California Wildlife Habitat Relationships (CWHR) Life History Accounts and Range Maps, provided by CDFW (CDFW, 2022b)
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Information, Planning and Conservation (IPaC), provided by the United States Fish and Wildlife Service (USFWS; USFWS, 2022a).
Environmental Conservation Online System (ECOS) Species Profiles, provided by USFWS (USFWS, 2022b)
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Critical Habitat Portal, provided by the USFWS (USFWS, 2022c).
National Wetlands Inventory (NWI), provided by the USFWS.
Inventory of Rare and Endangered Plants of California, 8th Edition and Vegetation Alliance Search provided by the California Native Plant Society (CNPS, 2022a, b). •
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National Hydrography Dataset, provided by the United States Geologic Survey (USGS; USGS, 2022).
Sawyer, J.O., T. Keeler-Wolf, J.M. Evens, 2009. A Manual of California Vegetation, Second Edition, provided by California Native Plant Society Press.
Meteorological station location information from National Oceanographic and Atmospheric Administration (NOAA) San Dimas Fire FC 95 (Station #047749), provided by Western Regional Climate Center (WRCC; WRCC, 2022a)
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• EPA Waters GeoViewer, provided by United States Environmental Protection Agency (USEPA; USEPA, 2022j).
Plant and wildlife species protected by federal agencies, state agencies, and nonprofit resource organizations, such as the California Native Plant Society (CNPS), are collectively referred to as “special-status species”. When plant and animal species that are federally or state listed endangered, threatened, or candidate species are discussed as a subcategory of special-status species they are referred to as “listed species”. When plant and animal species are protected by an agency but not a “listed species” and are discussed as a subcategory of special-status species they are referred to as “sensitive species.” Some of these plant and wildlife species are afforded special legal or management protection because they are limited in population size, and typically have a limited geographic range and/or habitat.
Aerial imagery from the above-mentioned sources was overlaid with geospatial data by utilizing Geographic Information System (GIS) software (ArcGIS 10.1) to identify documented observations of the following biological or environmental components within the project vicinity:
(1) Previously recorded observations within the project vicinity and geographic range of special-status species and potentially suitable habitats; (2) special-status vegetation communities;
(3) protected management lands;
(4) proposed and final critical habitat;
(5) waters of the United States (U.S.) and waters of the State of California (State), including wetlands; and
(6) wildlife corridors.
An analysis was then made to plan either the avoidance of or to minimize project impacts to any of those biological resources. A Biological Study Area (BSA) was defined for the project and includes (and is coterminous with) the proposed MCTA 20-0005 planning area (refer to Figure 4.4-1).
The general habitat assessment and vegetation mapping survey was conducted by UltraSystems biologists between June 30, 2022 and August 5, 2022 (see Appendix C, Biological Resources Evaluation). Areas within the BSA were surveyed during the daytime on foot by walking slowly across each habitat type, where accessible. Biologists used binoculars from strategic vantage points whenever direct access was not possible, due to private property with no access rights, chain-linked fences, and locked gates. Observations were also made with aerial imagery for inaccessible areas.
During the survey, observed plant and wildlife species, vegetation communities, and land cover types were identified and recorded.
Biologists identified and characterized existing vegetation communities, and assessed habitat to ascertain existing site conditions and identify habitat that could be suitable for special-status plant and wildlife species.
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Figure 4.4-1
BIOLOGICAL STUDY AREA (BSA)
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Observed vegetation communities were identified and mapped in the field by marking their limits on a color aerial map and/or with the use of a GPS unit. Descriptions of vegetation communities, land cover types and habitat within the BSA were based on the dominant perennial plant species or physical features. Generally, classifications of habitat types or vegetation communities were based on A Manual of California Vegetation, Second Edition (Sawyer et al., 2009) with modifications to better represent existing site conditions. Each habitat type identified in Sawyer et al. (2009) was cross-referenced with the following resources and classification systems so that a more accurate characterization of the existing habitat types and vegetation communities could be identified:
Preliminary Descriptions of the Terrestrial Communities of California (Holland, 1986), and the CDFW’s California Natural Community List (CDFW, 2022c).
Topography, soil characteristics, substrates, and disturbed and developed areas were also components of the habitat assessment to search for special-status plants and wildlife. Following the field mapping, UltraSystems’ GIS staff processed hand-drawn field maps and downloaded the data from the GPS units, and digitized the data into an ArcGIS file. Once the data were in ArcGIS, the acreage of each land cover type observed within the BSA was calculated.
Limitations of Survey Data and Analyses
The Biological Resources Evaluation (BRE; see Appendix C) documents the methods and results of the literature review, field surveys, and resulting impact analyses based on the existing project plans, project description, and other relevant data furnished by the City of San Dimas for the project.
Therefore, this Biological Resources section provides a summary of existing conditions and a determination of project-related impacts based on the best available data at the time of preparation.
The limitations of survey data and analyses are provided below:
1. This BRE incorporated findings from the original EIR documents (Takata Associates, 1991; The Planning Center, 1983; and UltraSystems, 1977) to inform our understanding of the existing biological resources at the time of the initial development of the project area. For example, the locations of the pre-project vegetation communities, protected trees, specialstatus species, wetlands and waters, and wildlife corridors, may not be adequately summarized in the historic documents. Erroneous or inadequate information within the baseline documents may affect findings within this BRE.
2. This BRE documents the initial reconnaissance-level evaluation of biological resources within the project area based on aerial photography, visual estimates of vegetation community boundaries, percent cover of dominant, co-dominant, and sub-dominant species, and photo documentation collected during field surveys.
3. The reconnaissance surveys (UltraSystems, 2022) were performed for the sole purpose of the MCTA 20-0005 project and do not absolve individual landowners from performing project-specific surveys during the engineering design phase.
For parcels supporting protected biological resources, focused surveys are required to meet local, regional, state, and federal regulations to accurately determine the resources within the MCTA-approved areas.
Landowners should be aware that biological resource surveys are generally valid for a duration of up to one to three years, dependent upon the survey focus. Due to the uncertainty 7145/San Dimas MCTA 20-0005 Page 4.4-5
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and temporal variation of individual parcel design, planning, and development phases, additional reconnaissance surveys may be combined with the initial focused biological surveys to meet the regulatory framework at the time any individual project is proposed.
Surveys would be performed for sensitive habitats, protected plants and wildlife species, wildlife corridors, proposed and designated land management areas, changes to species listing statuses, and jurisdictional areas (waters of the U.S., waters of the State).
Focused survey requirements vary season-to-season as determined by the species protocols.
Seasonally dependent surveys must occur within the required season; therefore, surveys may need to be performed up to one year (sometimes two) prior to expected construction. For example, if surveys must occur during the spring and summer, then the landowner must plan the project accordingly to coordinate mitigation with final grading permits. No focused protocol surveys were performed for this MCTA 20-0005 project.
4. Mitigation measures for avoidance, minimization, and compensatory mitigation are based on conditions at the time of survey. Potential impacts to protected resources will be refined during future focused protocol surveys. Additional mitigation may be necessary and should be employed based on the focused survey findings and regulatory context at the time of the proposed development.
5. Time of year, drought conditions, temperature, and individual surveyor observations may affect survey findings, although the margin for error is expected to be negligible during this reconnaissance-level survey.
6. The drainages displayed in Appendix A, Figures 12-12e Biological Constraints were derived from the NWI dataset, NHD datasets, USGS topographic maps, and field observations during the reconnaissance level surveys. Actual limits of jurisdictional areas require additional habitat assessments and may trigger formal jurisdictional delineations for parcels with wetlands and waters during the planning and design phase. Overlays provided are for informational purposes only until delimited at a future date.
Impact Types
Impact analysis is an important step in the CEQA process. Biological resources may be either directly or indirectly impacted by a project (defined by CEQA Guidelines § 15358). Direct and indirect impacts may be either permanent (long-term) or temporary (short-term) in nature (see Appendix C, BRE, Section 6.2).
This section discusses potential significant effects, or impacts, if any, to the environmental baseline and sensitive biological resources that could result from implementation of activities by individual property owners pursuant to the proposed MCTA. Individual properties were numbered 1 through 36 for reference, and potential impacts were determined with regard to each lot. With regard to potential or expected impacts and their related mitigation measures, MCTA-related activities will be referred to as “projects”.
Lot numbers and their associated Assessor’s Parcel Numbers (APNs) are provided in Table 4.4-1 and in Figure 4.4-2.
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Figure 4.4-2
RESIDENTIAL LOTS AND ASSOCIATED ASSESSOR’S PARCEL NUMBERS (APNs) 7145/San Dimas MCTA 20-0005
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Table 4.4-1
RESIDENTIAL LOTS AND ASSOCIATED ASSESSOR’S PARCEL NUMBERS (APNs) Lot Number APN Lot Number APN
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
8448-038-031
8448-038-032
8448-038-033
8448-038-034
8448-038-035
8448-038-036
8448-038-037
8448-038-038
8448-038-039
8448-038-040
8448-008-041
8448-038-041
8448-038-042
8448-038-043
8448-038-044
8448-008-042
8448-008-043
8448-008-044
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
8448-038-045
8448-038-046
8448-038-047
8448-008-045
8448-008-046
8448-008-047
8448-008-048
8448-008-055
8448-038-048
8448-038-049
8448-038-050
8448-038-051
8448-038-052
8448-038-053
8448-038-054
8448-038-055
8448-038-056
8448-038-057
Special-Status Plants
Plant species that are designated federally or state listed endangered, threatened, candidate, or state rare under the Endangered Species Act (ESA), California Endangered Species Act (CESA), and/or the California Native Plant Protection Act (NPPA) are referred to as “listed species”. Special-status plant species that have no designated status under the ESA, CESA, and/or the NPPA, but are designated as sensitive or locally important by federal agencies, state agencies, or nonprofit resource organizations such as the CNPS, are referred to as “sensitive” in the BRE.
Twenty-three special-status plant species were identified based on a literature review and query from publicly available databases (USFWS, 2022d; 2022e, CNDDB, 2022a, CNPS, 2022a) for reported occurrences within a ten-mile radius of the BSA. Each special-status plant species was assessed for its potential to occur within the BSA by comparing its habitat, elevation range and distribution obtained from the literature review, the CNPS website (CNPS, 2022a) and other databases with the location and elevation range of the BSA. A species was determined to have “no potential to occur” or as “not expected to occur” within the BSA if the BSA is outside the species’ known distribution and/or the species’ known elevation range, and/or if there is lack of suitable habitat conditions within the BSA to support the species.
Special-status plant species that were determined to have no potential to occur or are not expected to occur within the BSA were eliminated from further evaluation. The analysis of the occurrence potential of special-status plant species, including those determined to have no potential to occur or not expected to occur in the BSA can be found in the BRE. Twelve special-status plant species were determined to have at least a low potential to occur in the BSA. 7145/San Dimas MCTA 20-0005 Page 4.4-8
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Special-Status Wildlife
Wildlife species that are designated federally or state listed endangered, threatened, candidate, or state rare under the ESA, CESA, and/or the NPPA are referred to as “listed species”. Special-status wildlife species that have no designated status under the ESA, the CESA, and/or the NPPA, but are designated as sensitive or locally important by federal agencies, state agencies, local agencies and nonprofit resource organizations such as the CNPS are referred to as “sensitive” in the BRE.
Forty-seven special-status wildlife species were identified based on a literature review and query from publicly available databases (CNDDB, 2022a; USFWS, 2022d, e) for reported occurrences within a ten-mile radius of the BSA. These species were identified by one or more of the following means:
reported in the search, recognized as occurring based on previous surveys or knowledge of the area, or observed during the habitat assessment survey. Five listed and 20 sensitive wildlife species were determined to have at least a low potential to occur in the BSA. Three special-status species were observed in the BSA and were therefore determined to be present. These species are monarch butterfly, Nuttall’s woodpecker, and Cooper’s hawk.
Each special-status wildlife species was assessed for its potential to occur within the BSA by comparing its habitat range and distribution (if known) with the location and elevation range of the BSA. A species was determined to have no potential to occur or is not expected to occur within the BSA if the BSA is outside the species’ known geographic range and/or the species’ known elevation range. Through this analysis, 10 of the special-status wildlife species were determined to have no potential to occur or are not expected to occur within the BSA and were eliminated from further evaluation. It is anticipated that the project will have no impacts to these species and they are listed but not discussed further in the BRE.
Disclaimer Regarding MCTA Biological Analyses
The avoidance, minimization, and compensatory mitigation measures provided in Mitigation Measures BIO-1 through BIO-18 are intended to comprehensively address the potential impacts to biological resources within SP-11 as an entire ecological unit, and per individual parcel, based on preliminary reconnaissance surveys for the purposes of the MCTA. The MCTA considered conceptual impact areas at the time of review and were not applicable to project-specific impacts, which are unknown at this time.
The biological constraints that may require avoidance, minimization, and compensatory mitigation include sensitive vegetation communities, special-status species (e.g., plants and wildlife), seasonal species protections (e.g., reproduction and overwintering), jurisdictional wetlands and waters, riparian drainage segments, protected trees, wildlife corridors, and land management designations.
A qualified biologist will perform focused biological surveys for construction approvals, based on 65 percent to 95 percent complete professional engineering drawings at the time of proposed development of each individual parcel. The biologist conducting the focused surveys will incorporate the focused survey results and those of the reconnaissance surveys (UltraSystems, 2022) to assign the relevant mitigation for each individual project. The City will require the mitigation in the construction specifications prior to issuance of grading plans approved for each individual land owner (or project applicant). The mitigation measures contained herein are legally binding and are required if impacts to protected biological resources occur as a result of the project. 7145/San Dimas MCTA 20-0005 Page 4.4-9
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4.4.2 a)
Impacts Analysis
Would the project have a substantial adverse impact, 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? Less Than Significant with Mitigation Incorporated
The planning area is adjacent to urbanized areas and residential developments, including the residential developments within the BSA. The topography of the BSA can be generally characterized as an area of ridges and small vegetated canyons. Most of the ridges are developed with single-family residences on large parcels; these parcels slope toward the canyons and tend to be well-vegetated beyond their landscaped backyards. A detailed analysis of the biological resources and potential impacts to these resources that would result from implementation of the proposed MCTA 20-0005 to these resources can be found in Appendix C, Biological Resources Evaluation.
Plants
Approximately 53 plant species from 29 distinct plant families were observed within the BSA during the field survey. The dominant tree species are coast live oak and California black walnut, with occasional stands of Peruvian pepper trees; however, no special-status plant species were observed within the BSA during the surveys. Coast live oak woodland and California black walnut woodland are considered to be sensitive by CDFW (CDFW, 2022c). Coast live oak, California black walnut, and other mature significant trees occur throughout the planning area.
A literature review and query from publicly available databases (CDFW, 2022a; CNPS, 2022) found six special-status plant species that have been reported within a two-mile radius around the BSA; these species are shown on Figure 4.4-3. An analysis of existing conditions within the BSA determined that two listed and nine sensitive plant species were determined to have at least a low potential to occur within the BSA.
Special-status plants were not observed within the project site, but numerous species have the potential to occur due to the presence of suitable habitat in the BSA. The special-status plant species with at least a low potential to occur are listed below and are presented in the BRE, included as Appendix C of this document, with the taxonomic (scientific) name, common name, status and general habitat of each plant species. Species determined to have no potential to occur or not expected to occur due to lack of suitable habitat in the BSA and/or that the BSA is outside of the geographic and elevational range are also presented in the BRE (Appendix C of this document). The species reported in literature review were evaluated as to their occurrence potential based on habitat, elevational and geographic range and the project site disturbances (CNDDB 2022a; Calflora, 2022; CDFW, 2022; CDFW, 2022a, b; CNPS, 2022a; Jepson, 2022; USFWS, 2022a, b, c).
No listed or sensitive plants were observed during the biological field surveys, however focused surveys would be required for projects pursuant to the proposed MCTA to further evaluate whether these species are present or absent within a project site. 7145/San Dimas MCTA 20-0005 Page 4.4-10
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Figure 4.4-3
CNDDB KNOWN OCCURRENCES: PLANT SPECIES AND HABITAT
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Plant Species with a Potential to Occur in the BSA
Each special-status plant species was assessed for its potential to occur within the BSA by comparing its habitat range and distribution (if known) with the location and elevation range of the BSA. A species was determined as having “no potential to occur” within the BSA if the BSA is outside the species’ known distribution and/or the species’ known elevation range.
The following 14 special-status plant species were determined to have a low- to moderate potential to occur in the BSA; they are listed with their respective protection statuses determined by various state, federal, regional and local regulatory agencies listed below (see Appendix C, Biological Resources Evaluation for the descriptions of the status rankings and for further discussion of these species).
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thread-leaved brodiaea (Brodiaea filifolia) FT, SE, CRPR: 1B.1.
Nevin’s barberry (Berberis nevinii) FE, SE, CRPR: 1B.1 Sonoran maiden fern (Thelypteris puberula var. sonorensis) CRPR: 2B.2
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white rabbit-tobacco (Pseudognaphalium leucocephalum) CRPR: 2B.2 California satintail (Imperata brevifolia) CRPR: 2B.1
Plummer’s mariposa lily (Calochortus plummerae) CRPR: 4.2 slender mariposa lily (Calochortus clavatus var. gracilis) CRPR: 1B.2 intermediate mariposa lily (Calochortus weedii var. intermedius) CRPR: 1B.2 Robinson’s pepper grass (Lepidium virginicum var. robinsonii) mesa horkelia (Horkelia cuneata var. puberula) CRPR: 1B.1 Coulter’s saltbush (Atriplex coulteri) CRPR: 1B.2
many-stemmed dudleya (Dudleya multicaulis) CRPR: 1B.2
Sonoran maiden fern (Thelypteris puberula var. sonorensis) CRPR: 2B.2 Greata’s asper (Symphyotrichum greatae [=Aster greatae]) CRPR 1B.3 Parry’s spineflower (Chorizanthe parryi var. parryi) CRPR: 1B.2 Impacts to special-status plant species may occur as a result of implementation of the proposed MCTA due to the potential for special-status plant species to occur in the BSA. Special-status plant species occurring in areas adjacent to the BSA, including on conservation easements, could be indirectly impacted as a result of the project. Without appropriate avoidance and minimization measures for special-status plants, potentially significant impacts associated with subsequent construction include loss of habitat, loss or reduction of productivity, and direct mortality. Therefore, mitigation is required.
Wildlife
Based on a literature review and query from publicly available databases (CNDDB, 2022a; USFWS, 2022a, b, c) for reported occurrences within a ten-mile radius of the project site, 47 special-status wildlife species, 11 listed and 36 sensitive, were reported as recent occurrences (<20 years). These species were identified by one or more of the following means: reported in the search, recognized as occurring based on previous surveys or knowledge of the area, or observed during the habitat assessment survey (see BRE Appendix B, Special-Status Species and Potential Occurrence Determination). Of those 47 total species, three were observed within the BSA (see pp. 4.4-7 and 4.4- 8), five listed and 20 sensitive wildlife species were determined to have at least a low potential to occur in the BSA based on habitat requirements and known distribution. Nine of these special-status wildlife species have been reported within a two-mile radius around the BSA; these species are 7145/San Dimas MCTA 20-0005 Page 4.4-12
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shown on Figure 4.4-4. An analysis of existing conditions within the BSA determined that the five listed and 23 sensitive wildlife species listed below have a low- to moderate- potential to occur within the BSA.
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coastal California gnatcatcher (Polioptila californica californica) FT, SSC least Bell’s vireo (Vireo bellii pusillus) FE, SE, Season of concern: nesting Southwestern willow flycatcher (Empidonax traillii extimus) FE, SE arroyo toad (Anaxyrus californicus) FE, SSC
Swainson’s hawk (Buteo swainsoni) ST, BCC, Season of concern: nesting pallid bat (Antrozous pallidus) SSC
Crotch’s bumble bee (Bombus crotchii) SSC
merlin (Falco columbarius) WL
western spadefoot (Spea hammondii) SSC
yellow warbler (Setophaga petechia) SSC, BCC
large-blotched ensatina (Ensatina eschscholtzii klauberi) SSC coastal cactus wren (Campylorhynchus brunneicapillus sandiegensis) BCC two-striped garter snake (Thamnophis hammondii) SSC
Blainville’s horned lizard (Phrynosoma blainvilli) SSC
California glossy snake (Arizona elegans occidentalis) SSC hoary bat (Lasiurus cinereus) WBWG:M
western mastiff bat (Eumops perotis californicus) SSC, WBWG:H southern California rufous-crowned sparrow (Aimophila ruficeps canescens) WL mountain lion (Puma concolor) California Fish and Game Code §§ 4800 – 4810 white-tailed kite (Elanus leucurus) fully protected
golden eagle (Aquila chrysaetos) fully protected, WL, BCC, CDF:S, Season of Concern: nesting and wintering
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red-diamond rattlesnake (Crotalus ruber) SSC
southern California legless lizard (Anniella stebbinsi) SSC burrowing owl (Athene cunicularia) BCC
California spotted owl (Strix occidentalis occidentalis) SSC, BCC western yellow bat (Lasiurus xanthinus) SSC, WBWG:H
big free-tailed bat (Nyctinomops macrotis) SSC, WBWG:MH long-eared owl (Asio otus) SSC, Season of concern: nesting 7145/San Dimas MCTA 20-0005 Page 4.4-13
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Figure 4.4-4
CNDDB KNOWN OCCURRENCES: WILDLIFE SPECIES AND HABITAT
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The BSA supports an assortment of wildlife and provides foraging, nesting, breeding, and cover habitat to reptiles, birds (year-round residents, seasonal residents, migrants), and mammals. During the field surveys, 17 bird species, seven mammal species, and one invertebrate species were observed within the BSA. Three species special-status species were observed on the project site and are determined to be present (see Appendix C Biological Resources Evaluation).
One wildlife species, monarch butterfly (Danaus plexippus pop. 1), is a candidate for federal listing (overwintering population); two sensitive species, Nuttall’s woodpecker and Cooper’s hawk, were observed within the BSA during the field surveys BSA (see Appendix C, Biological Resources Evaluation). These species are further discussed below.
Special-Status Wildlife Species Present in the BSA
Monarch butterfly
Monarch butterfly was observed in the BSA during the surveys. Monarch butterflies are found across North America in areas of suitable feeding, breeding, and overwintering habitat. Two populations, referred to as the eastern and the western populations, are distinguished by separation by the Rocky Mountains.
Monarch presence in a given area within their range depends on the time of year. They are one of few migratory insects, traveling long distances between summer breeding habitat and winter habitat where they spend several months inactive. In the summer they range as far north as southern Canada.
In the fall the eastern population migrates to the cool, high mountains of central Mexico and the western population migrates to coastal California, where they spend the entire winter.
The overwintering population of this butterfly is designated as a federal candidate for listing.
Candidate species are plants and animals for which the USFWS has sufficient information on their biological status and threats to propose them for listing as endangered or threatened under the ESA, but for which development of a proposed listing regulation is precluded by higher priority listing actions to address species in greater need. A proposed regulation has not yet been published in the Federal Register for these species.
Nuttall’s woodpecker
Nuttall’s woodpecker is a common, permanent resident of low-elevation riparian deciduous and oak habitats, typically occurring in the Central Valley, Transverse and Peninsular Ranges, in the Coast Ranges north to Sonoma County and rarely to Humboldt County, and in lower portions of the Cascade Range and Sierra Nevada. This woodpecker primarily forages in oak and riparian deciduous habitats while pecking, probing, and drilling for sap. Approximately 80 percent of the diet of this species is comprised of adult and larval insects, mostly beetles. Berries, poison-oak seeds, nuts, other fruits are also occasionally consumed. Breeding season occurs from late March through early July with peak activity occurring from April to early June (Bent, 1939; CDFW, 2014, 2022b; Miller and Bock, 1972).
This species is currently designated by USFWS as a bird of conservation concern (BCC). BCC species are those listed in the USFWS’ 2021 Birds of Conservation Concern report (USFWS, 2021). The report identifies species, subspecies, and populations of all migratory and non-migratory bird species (beyond those already designated as federally threatened or endangered) that, without additional conservation actions, are likely to become candidates for listing under the ESA. While the bird species 7145/San Dimas MCTA 20-0005 Page 4.4-15
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included in the report are priorities for conservation action, the list makes no finding with regard to whether they warrant consideration for ESA listing.
Cooper’s hawk
Cooper’s hawks are medium-sized hawks of the woodlands. These raptors are commonly sighted in parks, neighborhoods, over fields, and even along busy streets if there are large trees nearby for perching, and adequate prey species such as other birds and small mammals. They prefer to breed in more densely wooded areas than occur in the BSA, such as woodland openings and edges of riparian and oak habitat (CDFW, 2014; Cornell Lab or Ornithology, 2022). Cooper’s hawks build nests in pines, oaks, Douglas-firs, beeches, spruces, and other trees. Males typically build the nest over a period of about two weeks, with just the slightest help from the female. Nests are piles of sticks roughly 27 inches in diameter and 6 to 17 inches high with a cup-shaped depression in the middle, eight inches across and four inches deep. The cup is lined with bark flakes and, sometimes, green twigs. (Cornell Lab of Ornithology, 2022).
Cooper’s hawk is included on the CDFW Watch List (CNDDB, 2022b).
Special-Status Species with a Potential to Occur in the BSA The BSA contains coastal sage scrub, coast live oak woodlands, California walnut groves, and other native vegetation, including riparian areas; therefore, the BSA results in the provision of suitable habitat for several listed wildlife species.
Coastal California gnatcatcher (CAGN)
The coastal California gnatcatcher (Polioptila californica californica; gnatcatcher) is found on the coastal slopes of southern California, from southern Ventura southward through Los Angeles, Orange, Riverside, San Bernardino, and San Diego counties into Baja California, Mexico. Within its range, the distribution of gnatcatcher is further defined by relatively narrow elevation limits. In general, inland populations of the gnatcatcher can be found below the 1,640-foot elevation, and coastal populations tend to be found below an elevation of 820 feet (CDFW, 2014).
The BSA contains suitable coastal sage scrub habitat to support this species.
Least Bell’s vireo
Least Bell’s vireo is a small, olive-grey migratory songbird, and is a summer resident of riparian areas in southern California. The species’ breeding distribution is currently restricted to eight California counties: Kern, San Diego, San Bernardino, Riverside, Ventura, Los Angeles, Santa Barbara, and Imperial. Preferred habitat for this species is dense willow-dominated riparian habitat with a welldeveloped understory. The understory shrub thickets provide nesting habitat. Willows are most commonly used. High and low shrub layers are used as foraging substrate. Other plant species used for nesting and foraging include California wild rose and coast live oak.
The BSA contains potentially suitable nesting habitat (coast live oak) required for this species. 7145/San Dimas MCTA 20-0005 Page 4.4-16
Initial Study/Mitigated Negative Declaration Page 1048 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
Southwestern willow flycatcher
The breeding range of the southwestern willow flycatcher (Empidonax traillii extimus; SWFL) includes southern California, Arizona, New Mexico, southwestern Colorado, and extreme southern portions of Nevada and Utah. Southwestern willow flycatcher breed and forage in relatively dense riparian tree and shrub communities associated with rivers, swamps, and other wetlands, including lakes (e.g., reservoirs). SWFL suitable habitat contains: surface water, saturated soil, or herbaceous wetland plants present during the early summer months; woody riparian vegetation is present and covers a minimum aerial extent of 20 percent over a 0.5-acre section of floodplain or adjacent streamside terrace; dense clumps or stands of woody vegetation are present. SWFLs also nest in thickets dominated by the non-native tamarisk and Russian olive, and in habitats where native and non-native trees and shrubs are present in essentially even mixtures.
The BSA contains potentially suitable nesting habitat for SWFL (woody vegetation, even mixtures of native and non-native trees and shrubs; the BSA may also contain saturated soils in the bottom of canyons within the BSA).
A variety of bird species are expected to be residents in the BSA, using the habitat throughout the year. Other species are present only during certain seasons. For example, the white-crowned sparrow (Zonotrichia leucophrys) and western bluebird (Sialia mexicana) are expected to occur in the BSA during the winter season and will then migrate north in the spring to breed during the summer.
Native bird species observed in the BSA include cliff swallow (Petrochelidon pyrrhonota), spotted towhee (Pipilo maculatus), lesser goldfinch (Spinus psaltria), American goldfinch, bushtit (Psaltriparus minimus), Nuttall’s woodpecker (Dryobates nuttallii), Cooper’s hawk (Accipiter cooperii), Bewick’s wren (Thryomanes bewickii), house wren (Troglodytes aedon), red-tailed hawk (Buteo jamaicensis), red-shouldered hawk (Buteo lineatus), and Anna’s hummingbird (Calypte anna).
Potential Impacts to Special-Status Species
California black walnut (Juglans californica) is present in the BSA; impact to this species as a vegetation community is described in Section 4.4(b). No additional listed or sensitive plants were observed within the BSA during the field surveys. However, the literature review and field surveys concluded that the majority of the plant species in the plant inventory have a moderate potential to occur within the BSA due to the presence of suitable habitat, soils, and/or other factors to support them.
One listed wildlife species, monarch butterfly, was observed within the BSA during the general biological surveys. However, the BSA has the potential to support additional listed wildlife species, including (but not limited to) coastal California gnatcatcher, least Bell’s vireo, southwestern willow flycatcher, Swainson’s hawk, and arroyo toad.
The project occurs within the Southern California/Central Coast Evolutionary Significant Unit (ESA) of the mountain lion, which is currently a Candidate State Threatened species. As a Candidate species, protections are given as a listed status species would be protected, which is fully protected under CESA.
Two sensitive wildlife species, Nuttall’s woodpecker and Cooper’s hawk, were observed within the BSA during the biological surveys. Habitat in the BSA may support additional sensitive species, including (but not limited to) golden eagle, red-diamond rattlesnake, southern California legless 7145/San Dimas MCTA 20-0005 Page 4.4-17
Initial Study/Mitigated Negative Declaration Page 1049 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
lizard, burrowing owl, California spotted owl, western yellow bat, big free-tailed bat, and long-eared owl.
Direct impacts to special-status plant species may occur as a result of implementation of the proposed MCTA due to the potential for special-status plant species to occur in the BSA. Specialstatus plant species occurring in areas adjacent to the BSA, including on conservation easements, could be indirectly impacted as a result of the project. Without appropriate avoidance and minimization measures for special-status plants, potential significant impacts associated with subsequent construction include loss of habitat, loss or reduction of productivity, and direct mortality.
Direct impacts to common and special-status wildlife occupying the BSA could occur from projectrelated mortality, injury, or harassment of individuals as a result of permanent development of project sites, and from the removal and direct loss of breeding, foraging, and/or sheltering habitat.
Permanent impacts include all areas within the limits of grading in individual project sites. Potential impacts include, but are not limited to:
• Ground-disturbing and habitat-altering activities could result in significant impacts to common and special-status ground-dwelling animals or nesting birds. Examples of such activities include grading, clearing, disking, grubbing, excavation, trenching, paving, mowing, compaction through use of heavy equipment, crushing of vegetation to access the project sites, vegetation and tree removal, and use of herbicides and pesticides. • Direct impacts to less mobile fossorial (burrowing) animals that dwell underground during most of the day or year (e.g., small mammals or lizards), or wildlife which have a life stage in the soil or on plants, could occur from encounters with vehicles or heavy equipment. Most of these animals cannot or do not run away from construction vehicles/equipment, and could be expected to experience direct mortality, injury, harassment, and displacement from increased human activity and vehicle/equipment travel if they are present at project sites at the time of construction. The loss of these animals could also affect other common and special-status wildlife in the food chain that depend on them as prey. •
•
The BSA also supports large trees and other physical features that could provide foraging, nesting, and cover habitat to support a diverse assortment of special-status bird species (year-round residents, seasonal residents, and migrants). It unlawful to take special-status birds, and their nests, eggs, and young. Activities which are most likely to result in take of migratory birds during the breeding bird season when eggs or young are likely to be present include, but are not limited to, clearing or grubbing of nesting bird habitat and tree removal.
The project has a potential to directly take individual breeding birds, their nests, young, or eggs.
Large trees and buildings in the BSA also provide suitable foraging and nesting habitat for special-status bat species. Clearing or grubbing of bat nesting habitat, including tree removal, is likely to impact special-status bats, including maternity roosts and hibernacula.
Indirect impacts could occur within areas located adjacent to project sites, including within conservation easements. Indirect impacts are more subtle than direct impacts. Indirect impacts may either be short-term (related to construction) or long-term, affecting populations and habitat quality 7145/San Dimas MCTA 20-0005 Page 4.4-18
Initial Study/Mitigated Negative Declaration Page 1050 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
over an extended period of time long after construction activities have been completed. Examples of indirect impacts include the following:
• The permanent loss of habitat including hunting, foraging, roosting, denning and/or breeding areas. Habitat loss could displace species from existing populations and impact nearby populations which may not be able to support them. This could result in delayed nest building, fewer breeding attempts, reduced size clutch or number of offspring, and an overall reduction in reproductive output.
• An increase and continuation of human activities within and adjacent to a project site could lead to mortality, injury, or harassment of wildlife species by providing anthropogenic food sources in the form of trash, litter, , water, or other food sources (e.g., domestic pets) which attract predators such as the common raven (Corvus corax), northern raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), mountain lion (Puma concolor), and coyote (Canis latrans).
• Introduction of new sources of artificial lighting could disrupt natural foraging and breeding behaviors and/or alter wildlife movement patterns and migratory routes of nocturnally active species such as mammals and snakes. Most animals would attempt to avoid moving in or near the lighting; however, some animals such as insects, migratory birds, and bats might be attracted to the lighting, increasing construction-related mortalities. Artificial lighting could also indirectly affect wildlife by increasing detection by predators. The new development could also provide an increase in artificial lighting and glare which could disrupt nocturnal wildlife behavior.
Details of potential direct and indirect impact to special-status plant and wildlife species can be found in Appendix C, Biological Resources Evaluation.
Mitigation Measures
Mitigation measures are intended to minimize or avoid direct or indirect impacts to biological resources to less than significant levels, and to comply with all applicable environmental laws, ordinances, policies, regulations, and management plans. Mitigation measures described in Section 4.4 would be applicable to each project and project owner (i.e., property owner) on the specified lots (see Table 4.4-2, Residential Lots and Associated Mitigation Measures) for activities pursuant to the proposed MCTA 20-0005.
Special-Status Plants Measures
Implementation of projects pursuant to the proposed MCTA may result in direct and indirect impacts to special-status plants (see Appendix C-1, Lot-Specific Impacts); therefore, mitigation measures are required (see Table 4.4-2).
Mitigation measure BIO-4, Focused Botanical Surveys, will require a qualified biologist to conduct focused botanical surveys for special-status plants that are likely to occur based on habitat, soils, elevation, climate, and other conditions, as described below. The focused plant surveys will be conducted in accordance with the Protocols for Surveying and Evaluating Impacts to Special Status Native Plant Populations and Sensitive Natural Communities (CNPS, 2018) and the Guidelines for Conducting and Reporting Botanical Inventories for Federally Listed, Proposed, and Candidate Plants (USFWS, 2000), and conducted in the field at appropriate times of the year to coincide with the 7145/San Dimas MCTA 20-0005 Page 4.4-19
Initial Study/Mitigated Negative Declaration Page 1051 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
growing season and different blooming periods, and when optimum conditions for identification (generally blooms, fruits, and leaves) are present. Biologists will pay special attention to those habitat areas that appear to provide suitable habitat for special-status species.
Following completion of the focused botanical surveys, a focused botanical survey report will be prepared in accordance with agency guidelines. The report will: 1) summarize information regarding the habitat of the survey area and the habitat’s suitability for special-status plants; 2) assess the potential presence of special-status plants onsite; 3) analyze the potential impacts to special-status plants from project development; and 4) recommend, as appropriate, BMPs, avoidance and protection measures, and mitigation measures to reduce or avoid potential impacts to special-status plants (see Section 7.4).
Mitigation measures BIO-1, BIO-2, BIO-3, and BIO-4 will also minimize or avoid impacts to specialstatus plant species, as described Special-Status Wildlife Measures
Special-status wildlife species were observed during the surveys, and the BSA contains habitat that could support additional special-status species. A negative survey finding does not preclude the occupation by special-status species of any location within the BSA. Several mitigation measures will be implemented to minimize and avoid impacts to special-status wildlife species.
Prior to project approval, applicants will implement the following mitigation measures: BIO-2 and BIO-3; BIO-5, Habitat Assessment for Least Bell’s Vireo and Southwestern Willow Flycatcher and BIO6, Focused Coastal California Gnatcatcher Surveys, to determine the presence and location of these species if they are occupying a project site. The applicant’s qualified (permitted) biologist will conduct these surveys in accordance with the methodology set forth below (or in accordance with current protocol or guidelines) and submit survey reports to the USFWS and to CDFW. If specialstatus bird species are present on a project site, the qualified biologist will consult with USFWS and CDFW to determine appropriate avoidance and mitigation measures to minimize impacts to these species.
Applicants will also implement mitigation measure BIO-7, Focused Cactus Wren Surveys prior to grading plan approval, to assess the presence of and use by cactus wren, as described below. If avoidance of occupied habitat is not possible, then payment into a mitigation bank or onsite restoration will occur (See BIO-1).
Because the BSA supports hunting and foraging habitat for mountain lions, applicants will implement mitigation measure BIO-8, Preconstruction Mountain Lion Avoidance (Natal Dens) prior to grading plan approval, to survey areas that may provide habitat for mountain lions to determine presence/absence and potential for natal dens and avoidance of impacts to mountain lions as described in in BIO-8.
Implementation of mitigation measure BIO-9, Preconstruction Wildlife Surveys, will ensure that sensitive wildlife species are cleared from a project site to the greatest practicable extent, thus minimizing direct impacts to sensitive wildlife species; BIO-10, 14-Day Preconstruction Burrowing Owl Surveys, will be implemented no more than 14 days prior to initiation of ground-disturbing activities will minimize or avoid potential impacts to burrowing owl, as detailed in Section 7.10; mitigation measure BIO-11, Preconstruction Bat Surveys, requires that a bat survey be conducted by a qualified biologist within 30 days prior to vegetation removal to minimize or avoid impacts to bats 7145/San Dimas MCTA 20-0005 Page 4.4-20
Initial Study/Mitigated Negative Declaration Page 1052 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
and bat maternity roosts. Mitigation Measure BIO-12, Preconstruction Breeding Bird Surveys, requires that a qualified biologist conduct preconstruction surveys for breeding birds (including hawks) and their nests.
Mitigation measure BIO-13, Worker Environmental Awareness Program (WEAP), requires all contractors, subcontractors, etc., working on a project site to attend a WEAP prior to performing any work on project site. The WEAP is intended to inform workers of the special-status plant and wildlife species known to occur on a project site, what species may occur, and steps to take if special-status species are observed by workers. Mitigation measure BIO-14, Biological Monitor, requires the presence of a qualified biological monitor on a project site. The biological monitor will ensure the implementation of mitigation measures BIO-15, Wildlife Entrapment Avoidance; and BIO-16, Construction Best Management Practices. These mitigation measures are intended to minimize or avoid direct and indirect impacts to wildlife through avoiding inadvertent entrapment of wildlife on a project site, and the maintenance of a clean project site to avoid attracting wildlife by littering and degradation of water quality, and accidental release of hazardous materials.
The biological monitor will also ensure the implementation of mitigation measures BIO-2 and BIO- 3.
Please see Table 4.4-2 for parcel-by-parcel mitigation relevant to potential impacts caused as a result of the activities pursuant to the proposed MCTA 20-0005. 7145/San Dimas MCTA 20-0005 Page 4.4-21
Initial Study/Mitigated Negative Declaration Page 1053 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
Table 4.4-2
RESIDENTIAL LOTS AND ASSOCIATED MITIGATION MEASURES
Jurisdictional
Delineation
Habitat
General
Vegetation
and
Wildlife
Avoidance
Pre- Worker
Environmental
Awareness
Program
Vegetation
Community
Replacement
Plan
Project
Limits and
Designated
Areas
Habitat
Assessment
for LBV &
SWFL
Focused
Cactus
Wren
Construction
Best
Significant
Tree
Protection
Measures
Focused
Botanical
Surveys
Focused
CAGN
Surveys
Construction
Mountain
Lion
Pre-con
Wildlife
Surveys
14-Day Precon BUOW
Surveys
Pre-con
Breeding
Bird Survey
Wildlife
Entrapment
Avoidance
Pre-con Bat
Surveys
Biological
Monitor Lot
No.
Management Assessment or
Surveys Practices as-needed
Survey Avoidance (WEAP)
BIO-1 BIO-2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
BIO-3
X
P
BIO-4 BIO-5 BIO-6 BIO-7 BIO-8 BIO-9 BIO-10 BIO-11 BIO-12 BIO-13 BIO-14 BIO-15: BIO-16 BIO-17 BIO-18 1 2
3 4
5 6
7 8
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
P
X
X
P
X
P
P
P
X
X
X
X
X
X
X
X
P
X
X
X
X
X
X
X
X
X
X
X
X
P
P
X
X
X
P
P
P
X
X
X
P
P
P
X
X
P
X
X
P
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
P
P
X
P X
X
X
P
P
P
X
P
P
P
P
X
X
X
X
X
X
X
P
X
X
X
P
P
P
X
X
X
P
P
P
X
P
P
P
P
P
P
P
P
X
X
X
X
X
X
X
P
X
X
X
P
P
P
X
X
X
P
P
P
X
P
P
P
P
P
P
P
P
P
P
X
X
X
X
P
X
X
X
X
X
P
P
P
X
X
P
P
P
X
P
P
P
P
P
P
P
P
P
P
X
X
X
X
P
X
X
X
X
X
P
P
P
X
X
P
P
X
X
P
P
P
X
P
P
P
P
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
P
P
P
P
P
P
P
X
X
X
X
P
P
P
P
P
P
X
X
X
X
X
X
X
X
X
X
X
X
X
P
X
X
X
P
X
X
X
P
P
P
P
X
P
P
P
X
X
X
X
X
X
X
X
X
X
X
X
P
P
P
X
X
P
P
P
X
P
P
X
X
P
P
P
P
X
X
X
X
X
X
P
P
X
X
X
X
P
P
X
X
P
P
P
P
X
P
X
X
X
X
X
X
X
X
X
X
X
X
X
P
P
X
X
X
X
P
P
X
X
P
P
P
P
X
P
X
P
P
P
P
P
P
P
P
X
X
P
P
P
X
X
X
X
P
X
P
X
P
P
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
P
P
P
X
X
X
X
X
P
P
P
X
X
P
P
P
P
P P
P
Note: X = Mitigation required for any area of the parcel P = Mitigation required if impacts extend into the "remaining parcel (extension to CE boundary) 7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
Mitigation Measures
MM BIO-1: Vegetation Community Replacement Plan
Sensitive natural communities (vegetation communities) are communities that have a limited distribution and are often vulnerable to the environmental effects of projects. These communities may or may not contain special-status species or their habitats. For purposes of this BRE, sensitive natural communities are considered to include vegetation communities listed in the CNDDB and communities (alliances and/or associations) listed in the CDFW Natural Communities List with a rarity rank of S1 (critically imperiled), S2 (imperiled), or S3 (vulnerable) (CDFW, 2022). Replacement and maintenance of natural resources will ecological viability as required in the FEIR (The Planning Center, 1983)), General Plan (Takata Associates, 1991), and as per CEQA § 21081.6 Findings or Negative Declarations; Reporting or Monitoring Project Changes; Effect on Environment; Conditions (CEQA § 21081.6).
As the project contains multiple areas of protected sensitive vegetation communities, including California walnut groves, coast live oak woodland and forest, coast prickly pear scrub, California sagebrush-black sage scrub, and/or California buckwheat scrub (if occupied by CAGN or other listed species), and if impacts cannot be avoided, then the following mitigation would be implemented.
Delimit Sensitive Vegetation Communities: A qualified biologist will survey the project site and field verify the mapped locations and extent of sensitive vegetation communities, per the 2022 surveys (Appendix A, BRE report; UltraSystems, 2022) If discrepancies are observed, then corrections will be made to determine the extent of impact. For areas that are inaccessible due to topography and/or dense vegetation, a visual estimate may be used to map the vegetation extent via binocular survey, photo documentation, drawn on aerial imagery, then digitized using GIS to estimate the number, maturity, condition, and habitat value of the sampled area. Mitigation will then be fulfilled as follows.
Compensatory mitigation is required for impacts to sensitive natural communities per § 21081.6 Findings or Negative Declarations; Reporting or Monitoring Project Changes; Effect on Environment; Conditions. The following compensatory mitigation is provided:
Mitigation Bank. The primary, streamlined approach for compensatory mitigation is payment into a local mitigation bank. The project should ideally be within the service area for the mitigation bank providing available credits for “in kind” impacts to the aforementioned sensitive vegetation communities. The minimum compensatory mitigation ratio for sensitive vegetation communities will be 3:1. If the project applicant uses an existing mitigation bank, such as Soquel Canyon Mitigation Bank8: (https://landveritasmitigationbanks.com/soquel.html) or similar, the fee fully mitigates onsite impacts and no further mitigation for is necessary per BIO-1.
Vegetation Communities Replacement Plan (in lieu of mitigation bank). In the event impacts cannot be mitigated through an approved mitigation bank, then on-site and/or off-site replanting is required at a 3:1 ratio for the impacted vegetation. The replacement plantings will be planted to mimic the surrounding natural habitat in an effort to retain the functions and values per each treedominated vegetation community. 8 The Soquel Mitigation Bank is administered by Land Veritas and provides mitigation credits for walnut woodlands, oak woodlands, and coastal sage scrub.
7145/San Dimas MCTA 20-0005 Page 4.4-23
Initial Study/Mitigated Negative Declaration Page 1055 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
A certified arborist, qualified biologist, or licensed landscape architect will prepare a Vegetation Communities Replacement Plan (“habitat mitigation and monitoring plan;";" HMMP) which shall be submitted to the City of San Dimas and CDFW (as feasible) for approval. A project-specific HMMP will include location and techniques for habitat restoration//revegetation. The HMMP will define the proposed mitigation site, mitigation site preparation, installation of native vegetation replacement, seed palette, irrigation schedule, maintenance, monitoring, reporting, and performance success criteria. The HMMP will recommend feasible measures for mitigating any impacts to trees, sensitive native vegetation water quality, riparian, and biological resources from project implementation. The minimum monitoring period for restoration and replanting will be 5-years.
In addition to protecting sensitive vegetation communities, BIO-1 may also serve to satisfy a portion of the requirements of the City of San Dimas tree protection ordinances (§§ 16.42.020, 16.42.090,
18.162.060, 18.162. 070, and 18.162.100) as mandated by the City’s required tree removal permit for Mature Significant Trees (see Section 7.18 and MM BIO-18, below).
MM BIO-2: Project Limits and Designated Areas
To avoid impacts to sensitive biological resources, the property owners will collectively implement the following measures prior to project construction and commencement of any ground-disturbing activities or vegetation removal.
• Specifications for the project boundary, limits of construction, project-related parking, storage areas, laydown sites, and equipment storage areas will be mapped and clearly marked in the field with temporary fencing, screens, silt fencing, signs, stakes, flags, rope, cord, or other appropriate markers.
• All markers will be maintained until the completion of activities in that area. Construction employees will be informed to strictly limit their activities, vehicles, equipment, and construction materials to the proposed project footprint and designated staging areas and routes of travel. The construction area(s) shall be the minimal area necessary to complete the project and shall be specified in the construction plans. • The construction crew will inspect excavated areas daily to detect the presence of trapped wildlife. See BIO-15 Wildlife Entrapment Avoidance and BIO-16 Construction Best Management Practices, below.
MM BIO-3: General Vegetation and Wildlife Avoidance and Protection Measures The BSA contains habitat which can support many wildlife species. The property owner shall implement the following general avoidance and protection measures to protect vegetation and wildlife, to the extent practical:
• Cleared or trimmed native vegetation and woody debris will be chipped and left onsite. If cleared or trimmed non-native, invasive vegetation are in the flowering and/or seeding/fruiting stages, then the seed heads will be bagged tightly and disposed of in a legal manner at an approved disposal site (landfill) as soon as possible to prevent regrowth and the spread of weeds.
7145/San Dimas MCTA 20-0005 Page 4.4-24
Initial Study/Mitigated Negative Declaration Page 1056 – 2053 December 2022 ❖ SECTION 4.4 - BIOLOGICAL RESOURCES ❖
• The removal of native vegetation shall be avoided and minimized to the maximum extent practicable. Temporary impacts shall be returned to pre-existing contours and revegetated with appropriate native species.
•
•
Vehicles and equipment will be free of caked mud or debris prior to entering a project site to avoid the introduction of new invasive weedy plant species.
To minimize construction-related mortalities of nocturnally active species such as mammals and snakes, it is recommended that all work be conducted during daylight hours. Nighttime work (and use of artificial lighting) will not be permitted unless specifically authorized. If required, night lighting will be directed away from the preserved open space areas to protect species from direct night lighting. All unnecessary lights will be turned off at sunset to avoid attracting wildlife such as insects, migratory birds, and bats. •
•
•
If any wildlife is encountered during the course of project activities, said wildlife will be allowed to freely leave the area unharmed.
Wildlife will not be disturbed, captured, harassed, or handled. Animal nests, burrows and dens will not be disturbed without prior survey and authorization from a qualified biologist.
Covered trash receptacles will be placed at each designated work site and the contents will be properly disposed at least once a week. Trash removal will reduce the attractiveness of the area to opportunistic predators such as common ravens, coyotes, northern raccoons, and Virginia opossums.
•
•
The contractors and project applicant will ensure that storm water BMPs include erosion control measures for construction-related disturbance near undeveloped land with ponded water to avoid sedimentation of breeding grounds for special-status sensitive amphibians and invertebrates, such as the spadefoot toad.
Post-construction lighting. The MCTA will ensure that construction specifications provide provisions to reduce light pollution, including down-shielding or removal of motion sensor lighting, as this type of lighting can deter wildlife and impede movement throughout the area.
Night lighting can disrupt the circadian rhythms of many wildlife species. Therefore, if night lighting is required at entry points, we recommend low level lighting. All non-essential lighting should be eliminated. The Project should avoid or limit the use of artificial light during the hours of dawn and dusk, as these intervals of time are when many wildlife species are most active.
MM BIO-4: Focused Botanical Surveys
To avoid impacts to special-status plant species, a qualified biologist will survey the project site for the presence of special-status plant species that are likely to occur based on habitat, soils, elevation, climate, and other conditions of the project site. The focused plant surveys will be conducted in accordance with the Protocols for Surveying and Evaluating Impacts to Special Status Native Plant Populations and Sensitive Natural Communities (CNPS, 2018) and the Guidelines for Conducting and Reporting Botanical Inventories for Federally Listed, Proposed, and Candidate Plants (USFWS, 2000).
The surveys will be conducted in the field at appropriate times of the year to coincide with the growing season and different blooming periods and when optimum conditions for identification 7145/San Dimas MCTA 20-0005 Page 4.4-25
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(generally blooms, fruits, and leaves) are present. Biologists will pay special attention to those habitat areas that appear to provide suitable habitat for special-status species.
A minimum of two surveys would be conducted during different seasons of the same year to adequately capture the floristic diversity of a site, with a focus on areas that will be directly or indirectly receiving impacts from project activities. Plant taxa that occur on site will be identified to the taxonomic level necessary to determine rarity and listing status, as feasible. Plant species will be identified by an expert botanist if a question of rarity and listing status occurs. Special-status plant species will be identified, recorded in field notes, counted or estimated, and mapped on an aerial map or with a GPS unit.
Following completion of the focused botanical surveys, a focused botanical survey report will be prepared in accordance with agency guidelines. The report will: 1) summarize information regarding the habitat of the survey area and the habitat’s suitability for special-status plants; 2) assess the potential presence of special-status plants onsite; 3) analyze the potential impacts to special-status plants from project development; and 4) recommend, as appropriate, BMPs, avoidance and protection measures, and mitigation measures to reduce or avoid potential impacts to special-status plants. The report will include: 1) methods and results of the literature review and field surveys; 2) figures depicting the location of special-status plants; 3) a complete flora compendium; and 4) site photographs.
Because CDFW generally considers botanical surveys to be valid for a period of up to three years, some aspects of the proposed project may warrant periodic updated surveys for certain sensitive taxa, particularly if the project is proposed to occur over a protracted time frame, or in phases, or if surveys are completed during periods of drought.
MM BIO-5: Habitat Assessment for Least Bell’s Vireo and Southwestern Willow Flycatcher Potential indirect impacts to downstream riparian habitat may require a biologist with a valid Section 10(a)(1)(A) permit will perform a habitat assessment for the least Bell’s vireo (LBV) (Vireo bellii pusillus) and the southwestern willow flycatcher (SWFL) (Empidonax traillii extimus) to determine if the downstream riparian areas may support special-status species and project activities may cause an adverse effect (direct or indirect) to said species.
If the qualified biologist determines there is potential for project activities to cause an adverse effect (direct or indirect) to special-status avian species, then the authorized biologist will conduct protocol LBV surveys in accordance with the United States Fish and Wildlife’s (USFWS) LBV Survey Guidelines (dated February 1992 and revised January 19, 2001 [USFWS, 2001]) and protocol SWFL surveys in accordance with the guidelines set forth by the USFWS and the United States Geological Survey (USGS) survey protocol for the SWFL (dated July 11, 2000 [USFWS, 2000] and revised June 22, 2010 [Sogge et al., 2010]). This habitat assessment report will be submitted to USFWS and the South Coast (Region 5) CDFW office within 45 days of survey effort completion. In addition, all survey efforts completed during the calendar year should be submitted to the abovementioned agencies (USFWS, 2001a).
MM BIO-6: Focused Coastal California Gnatcatcher Surveys The BSA is located in the known distributional range of the California gnatcatcher (CAGN) and contains suitable coastal sage scrub habitat (coast prickly pear scrub, California sagebrush-black sage scrub, California buckwheat scrub) to potentially support this bird; therefore, focused surveys in 7145/San Dimas MCTA 20-0005 Page 4.4-26
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accordance with the Coastal California Gnatcatcher Presence/Absence Survey Protocol (USFWS, 1997; survey protocol) will be required. The property owners will be responsible for retaining a qualified biologist holding a Section 10(a)(1)(A) permit issued by the USFWS to conduct focused surveys for CAGN. This authorized biologist will coordinate with the Carlsbad USFWS Office prior to survey.
A minimum of six surveys shall be conducted at least one week apart, between March 15 and June
30. A minimum of nine surveys shall be conducted at least two weeks apart between July 1 and March
14. Surveys should be conducted between the hours of 6:00 a.m. and 12:00 p.m. and shall avoid period of inclement conditions. No more than 80 acres of suitable CAGN habitat should be surveyed per biologist per day.
If avoidance of occupied habitat is not possible, then payment into a mitigation bank or onsite restoration will occur (See BIO-1).
A survey report should then be prepared and submitted with 45 days from survey effort completion to the Carlsbad USFWS Office and the CDFW South Coast (Region 5) Office. The survey report should include the names and permit numbers of all surveyors, survey area locations, descriptions of and mapped extent of the vegetation communities in the survey area and areas adjacent. Number, age, sex, and applicable color band information for detected CAGNs should be reported by the authorized biologist.
Note: Incidental observations of raptors and sensitive avian species shall be recorded during the CAGN surveys; incidental species include but are not limited to: Cooper’s hawk, merlin, golden eagle, burrowing owl, California spotted owl, long-eared owl, coastal cactus wren, yellow warbler, and southern California rufous-crowned sparrow.
MM BIO-7: Focused Cactus Wren Surveys
The BSA is located in the known distributional range of the cactus wren (Campylorhynchus brunneicapillus) [CAWR] and contains suitable coastal sage scrub habitat (coast prickly pear scrub, California sagebrush-black sage scrub, California buckwheat scrub) to potentially support this bird; therefore, focused surveys for this species should occur within areas of suitable habitat.
Cactus wren and the CAGN (see BIO-6) occur within similar suitable habitats. Providing that the authorized biologist with a Section 10(a)(1)(A) recovery permit for CAGN has the experience and expertise to conduct the CAWR survey, surveys may be conducted concurrently. If avoidance of occupied habitat is not possible, then payment into a mitigation bank or onsite restoration will occur (See BIO-1)
MM BIO-8: Preconstruction Mountain Lion Surveys (for Natal Dens) The project occurs within the Southern California/Central Coast Evolutionary Significant Unit (ESA) of the mountain lion, which is currently a Candidate State Threatened species. As a Candidate species, protections are given as a listed status species would be protected, which is full protections under CESA.
Protections are for mountain lion wildlife corridors, and potential hunting, foraging habitat, and breeding opportunities within the area of the proposed MCTA. . A qualified biologist familiar with the mountain lion species behavior and life history should conduct pre-construction surveys within the 7145/San Dimas MCTA 20-0005 Page 4.4-27
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project area and 500-foot buffer that occur within 30 days prior to project mobilization and groundmoving activities (clear, grub, grade, excavation, etc.) A qualified biologist familiar with the mountain lion species behavior and life history should conduct surveys in areas that may provide possible habitat for mountain lion to determine the potential presence/absence of natal dens for the species. Surveys should be conducted when the species is most likely to be detected, during crepuscular periods at dawn and dusk. Survey results including negative findings should be submitted to CDFW prior to initiation of project activities.
Should an active natal den be located within 500 feet of the project site, the applicant should cease work and inform CDFW with 24 hours. No construction activities should occur in the 500-foot buffer zone until a qualified biologist in consultation with CDFW establishes an appropriate setback from the den that would not adversely affect the successful rearing of the cubs. No construction activities or human intrusion should occur within the established setback until the cubs have been successfully reared or the cats have left the area.
If take or adverse impacts to mountain lion cannot be avoided either during project construction and over the life of the project, project proponent shall consult CDFW and must acquire a CESA Incidental Take Permit (pursuant to Fish & Game Code, §2080 et seq.).
If there are no adverse effects to the mountain lion habitat, then project activities may commence without further mitigation.
MM BIO-9: Preconstruction Wildlife Surveys
To comply with California Fish and Game Code §§ 2050-2089, § 3511, § 4700, § 5050 and § 5515, the following measures will be implemented to minimize impacts to sensitive species which include, but are not limited to: southern California legless lizard, Crotch’s bumble bee, western spadefoot toad, large-blotched ensatina, coast range newt, two-striped garter snake, Blainville’s horned lizard, California glossy snake, and red diamond rattlesnake. The measures below will help to minimize or avoid direct and indirect impacts caused by project implementation to sensitive species. •
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The project applicant will retain a qualified biologist to conduct pre-construction wildlife surveys within the applicant’s APN (aka. project site) and associated conservation easements.
The survey will be conducted at least seven days prior to the onset of scheduled activities, (e.g., staging and stockpiling, structure removal, clear and grub, grading, fill, etc.).
Pre-construction surveys for special-status wildlife species will concentrate attention in areas with potential to detect protected species, their nests, or indicators of presence (i.e., tracks, middens, fur, pellets, claw marks, scat, burrows, and/or vocalizations); observations of special-status species and/or sign will be recorded and mapped. During the surveys, the biologist will also record incidental observations of non-special-status species and/or their sign.
• Upon completion of the pre-construction wildlife surveys, the qualified biologist will prepare a brief letter report summarizing methods, results, and recommendations for project commencement. If a greater than seven days lapse in construction-related activities occurs within the subject parcel then an additional pre-construction survey is required. 7145/San Dimas MCTA 20-0005 Page 4.4-28
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•
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If it is determined that a federally-listed and/or state-listed or sensitive plant/wildlife species will be directly impacted by the project, the qualified biologist will consult with the USFWS in accordance with the Endangered Species Act § 7 and the CDFW in accordance with CESA under California Fish and Game Code § 2081(b), respectively. However, if the qualified biologist conducts thorough pre-construction surveys and determines there is no threat to special-status species, then construction may commence.
Sensitive wildlife species and/or potential nesting sites will not be disturbed, captured, handled or moved.
MM BIO-10: 14-Day Preconstruction Burrowing Owl Surveys and Report A qualified biologist will conduct a preconstruction BUOW survey (Take Avoidance Survey) in accordance with the Staff Report on Burrowing Owl Mitigation (Staff Report) (CDFG, 2012) no less than 14 days prior to initiating ground disturbance activities. The survey shall be conducted in accessible portions of the Biological Study Area (BSA), a zone 500 feet out from the project site that contains BUOW essential habitat (nesting, foraging, wintering, and dispersal habitat). The survey will be conducted from sunrise to 10:00 a.m. or from two hours before sunset until evening twilight when weather conditions are conducive to BUOW observations. The biologist shall walk belt transects spaced no more than 20 meters apart to allow 100 percent visual coverage of the survey area, and examine entrances of potential burrows and suitable man-made structures for BUOWs and signs of BUOW. The biologist shall identify, record, and map with a global positioning system (GPS) unit BUOWs and potential BUOW signs. Detailed notes, including observations of wildlife species encountered during the survey, shall be recorded in field notes. A final preconstruction BUOW survey (Take Avoidance Survey) shall be conducted within 24 hours prior to ground disturbance, following the survey methodology described above (CDFG 2012).
Following the completion of the preconstruction BUOW surveys, the biologist shall prepare and electronically submit to the applicant a report summarizing the results of the survey. The report shall be prepared in accordance with the instructions described in the Staff Report. The applicant will submit one electronic copy to the project proponent and one electronic copy of the report to the City for review and concurrence prior to conducting project activities. • The results of the 14-day preconstruction BUOW surveys will be valid for 14 days. If construction is delayed more than 14 days, then the 14-day preconstruction BUOW surveys must be repeated. That will require a change order.
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If no BUOW or signs of BUOW are observed during the survey and concurrence is received from the City, project activities may begin and no further mitigation will be required.
If BUOW or signs of BUOW are observed during the survey, the site will be considered occupied and the BUOW may require noise and activity shielding BMPs and/or require passively relocation. The qualified biologist will notify the City and contact CDFW to assist in the development of avoidance, minimization, and mitigation measures prior to commencing project activities. A passive relocation program (Burrowing Owl Mitigation Monitoring and Artificial Burrow and Exclusion Plan) may be necessary and will require approval by CDFW prior to commencing project activities.
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MM BIO-11: Preconstruction Bat Surveys
The BSA provides suitable oak woodland habitat and other large trees and structures including buildings that provide roosting sites for several special-status bay species. Three sensitive bat species were determined to have a moderate potential to occur in the BSA due to presence of suitable habitat and recent occurrences data (CNDDB, 2022a). These species are pallid bat, western mastiff bat, and big free-tailed bat.
Within 30 days prior to commencement of vegetation removal, a preconstruction bat survey shall be conducted by a qualified biologist during nighttime hours for the presence of any roosting bats.
Acoustic recognition technology shall be used for the bat survey if feasible and appropriate. If either a bat maternity roost or hibernacula (structures used by bats for hibernation) are present, a qualified biologist shall develop and implement appropriate protection measures for that maternity roost or hibernacula.
If either a maternity roost or hibernacula, which are structures used by bats for hibernation, is identified, a qualified biologist shall develop and implement appropriate protection measures for that maternity roost or hibernacula. These protection measures shall include, as appropriate, safely evicting non-breeding bats, establishment of avoidance buffers, or replacement of roosts at a suitable location.
MM BIO-12: Preconstruction Breeding Bird Survey
To maintain compliance with the MBTA and Fish and Game Code and to avoid impacts or take of migratory non-game breeding birds and other native birds, their nests, young, and eggs, the following measures will be implemented. Impacts to nesting birds would be a potential significant impact if protected breeding birds are present, therefore, the measures below will help to reduce direct and indirect impacts caused by construction-related activities to less than significant levels. • If project activities cannot be avoided during February 15 through September 15, a qualified biologist will conduct a preconstruction breeding bird survey for active nests (adult birds, eggs, nestlings, fledglings, and those dependent upon the nest). The breeding bird nesting season is typically from but can vary slightly from year to year, usually depending on weather conditions.
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The survey will be conducted between three to seven days prior to the onset of scheduled activities and will include all potential nest sites, such as open ground, trees, shrubs, grasses, burrows, and structures during the breeding season.
The project applicant will make every effort to conduct the pre-construction survey and subsequent removal of all physical features that could potentially serve as nest sites (e.g., staging and stockpiling, structure removal, clear and grub, grading, fill, etc.) to avoid impacts to nesting birds.
• If a breeding bird territory or an active bird nest is located during the pre-construction survey and will potentially be impacted, the site will be mapped and location provided to the construction foreman, City, and project applicant. The qualified biologist will establish a buffer zone around the active nest, which will be delimited (fencing, stakes, flagging, orange snow fencing, etc.) at a minimum of 100 feet or as the qualified biologist determines is 7145/San Dimas MCTA 20-0005 Page 4.4-30
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appropriate for the detected species. The biologist will determine the appropriate buffer size based on the planned activities and tolerances of the nesting birds. This no-activity buffer zone will not be disturbed until a qualified biologist has determined that the nest is inactive, the young have fledged, the young are no longer being fed by the parents, the young have left the area, or the young will no longer be impacted by project activities. Periodic monitoring by a biologist will be performed to determine when nesting is complete. Once the nesting cycle has finished, project activities may begin within the buffer zone. •
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If listed bird species are observed within a project site during the preconstruction survey, the biologist will immediately map the area and notify the appropriate resource agency to determine suitable protection measures and/or mitigation measures and to determine if additional mitigation is necessary. Project activities may begin within the area only when concurrence is received from the appropriate resource agency.
Birds or their active nests will not be disturbed, captured, handled or moved. Active nests cannot be removed or disturbed; however, nests can be removed or disturbed if determined inactive by a qualified biologist.
If no breeding birds or active nests are observed during the preconstruction survey or they are observed and will not be impacted, project activities may begin and no further mitigation will be required.
MM BIO-13: Worker Environmental Awareness Program (WEAP) Prior to project construction activities, a qualified biologist will prepare and conduct a Worker Environmental Awareness Program (WEAP) to describe the biological constraints of the project. • All personnel who will work within a project site will attend the WEAP prior to performing any work. The WEAP will include, but not be limited to: results of preconstruction surveys; description of sensitive biological resources potentially present within a project site; legal protections afforded the sensitive biological resources; BMPs for protecting sensitive biological resources (i.e., restrictions, avoidance, protection, and minimization measures); individual responsibilities associated with the project. The program will also include the reporting requirements if workers encounter a sensitive wildlife species (i.e., notifying the biological monitor or the construction foreman, who will then notify the biological monitor). •
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A condition shall be placed on grading permits requiring a qualified biologist to conduct a training session for project personnel prior to grading.
Training materials will be language-appropriate for all construction personnel. Upon completion of the WEAP, workers will provide their signature on a “sign-in sheet” stating that they attended the program, understand all protection measures, and will abide all the rules of the WEAP. A record of all trained personnel will be kept with the construction foreman at the project field construction office and will be made available to any resource agency personnel.
• If new construction personnel are added to the project later, the construction foreman will ensure that new personnel receive training before they start working. The biologist will provide written hard copies of the WEAP and photos of the sensitive biological resources to the construction foreman.
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MM BIO-14: Biological Monitor
A qualified project biologist shall monitor construction activities for the duration of the project to ensure that practicable measures are being employed to avoid incidental disturbance of habitat and species of concern outside the project footprint.
If special-status wildlife species or nesting bird species are observed and determined present within a project site during the pre-construction surveys or as required by the resource agencies, then a biological monitor shall be onsite to monitor throughout earth-moving activities that result in tree or vegetation removal, to minimize the likelihood of inadvertent impacts to protected biological resources. Monitoring shall also be conducted periodically during construction activities to ensure no new nests are built during any vegetation removal or building demolition activities between February 15 through September 15. The biological monitor shall ensure that all BMPs, avoidance, protection and mitigation measures described in the relevant project permits and reports are in place and are adhered to.
The biological monitor shall have the authority to temporarily halt all construction activities and all non-emergency actions if protected biological resources are identified and would be directly affected.
The monitor shall notify the project applicant, the City, and then the appropriate resource agency if the issue cannot be resolved. If necessary, the biological monitor shall relocate wildlife “out of harm’s way,”,” outside of the work area. Work can continue at the location if qualified biological monitor determines that the activity will not result in adverse effects on the protected resource.
The appropriate agencies shall be notified if a dead or injured protected species is located within a project site. Written notification shall be made within 15 days of the date and time of the finding or incident (if known) and must include location of the carcass, a photograph, cause of death (if known), and other pertinent information.
MM BIO-15: Wildlife Entrapment Avoidance
Project-related excavations shall be secured to prevent wildlife entry and entrapment. • Holes and trenches shall be backfilled, securely covered, or fenced. Excavations that cannot be fully secured shall incorporate appropriate wildlife ramp(s) at a slope of no more than a 3:1 ratio (horizontal: vertical), or other means to allow trapped animals to escape. •
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Biological monitors shall provide guidance to construction crews to ensure that wildlife ramps or other means are sufficient to allow trapped animals to escape.
At the end of each work day, a biological monitor shall ensure that excavations have been secured or provided with appropriate means for wildlife escape.
All pipes or other construction materials or supplies will be covered or capped in storage or laydown areas. No pipes or tubing will be left open either temporarily or permanently, except during use or installation.
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Any construction pipe, culvert, or other hollow materials will be inspected for wildlife before it is moved, buried, or capped. This type of inspection will be conducted to preclude or minimize potential impacts to all targeted species.
MM BIO-16: Construction Best Management Practices
Project work crews will be directed to use BMPs where applicable. These measures will be identified prior to construction and incorporated into the construction operations.
Implementation of this mitigation measure will help to avoid, eliminate or reduce impacts to sensitive biological resources, such as special-status terrestrial wildlife species, to less than significant levels. BMPs that apply to this project construction and development are as follows:
• Water pollution and erosion control plans shall be developed and implemented in accordance with Los Angeles Regional Water Quality Control Board (RWQCB) requirements (i.e., National Pollutant Discharge Elimination System [NPDES], § 401 Clean Water Act [CWA],], and/or SWRCB Resolution No. 2019-0015 [Waste Discharge Requirements]).]). • Equipment storage, fueling, and staging areas shall be located on upland sites with minimal risks of direct drainage into riparian areas or another sensitive habitat. These designated areas shall be located in such a manner as to prevent any runoff from entering sensitive habitat. Necessary precautions shall be taken to prevent the release of cement or other toxic substances into surface waters. Project related spills of hazardous materials shall be reported to appropriate entities including but not limited to applicable jurisdictional areas per the City, USFWS, CDFG and RWQCB, and shall be cleaned up immediately and contaminated soils removed to approved disposal areas.
The natural resource agencies shall have the right to access and inspect any sites of approved projects including any restoration/enhancement area for compliance with project approval conditions including these BMPs.
Level of Significance with Mitigation Incorporated
The BSA contains at least one sensitive plant species, California black walnut. Conditions on the project site may support additional special-status plant species; therefore, the project is anticipated to have direct impacts to listed or sensitive plants. The project is also anticipated to have indirect impacts to special-status plant species through loss of habitat, loss or reduction of productivity, and other future habitat modifications. Implementation of mitigation measures BIO-1, BIO-2, BIO-3, and BIO-4 would minimize or avoid significant impacts to special-status plant species to less than significant.
The BSA contains at least three special-status wildlife species: monarch butterfly, Nuttall’s woodpecker and Cooper’s hawk. Conditions on the project site may support additional special-status wildlife species; therefore, the project is anticipated to have direct impacts to listed or sensitive wildlife. The project is also anticipated to have indirect impacts to special-status wildlife species through increased ambient noise, human activities, lighting, etc. Implementation of mitigation measures BIO-2 through BIO-16 would minimize or avoid significant direct and indirect impacts to special-status wildlife species to less than significant. 7145/San Dimas MCTA 20-0005 Page 4.4-33
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b) Would the project have a substantial adverse impact on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? Less Than Significant with Mitigation Incorporated
The planning area is adjacent to urbanized and residential developments, including the residential developments within the BSA. The topography of the BSA can be generally characterized as an area of ridges and small vegetated canyons. Most of the ridges are developed with single-family residences on large parcels; these parcels slope toward the canyons and tend to be well-vegetated beyond their landscaped backyards. A detailed analysis of the biological resources and potential impacts to these resources that would result from implementation of the proposed MCTA to these resources can be found in Appendix C, Biological Resources Evaluation.
Project activities pursuant to the proposed MCTA 20-0005 are anticipated to result in direct impacts (permanent loss of vegetation) to sensitive vegetation communities and habitat such as coast live oak woodland, California walnut groves, coast prickly pear scrub, and California buckwheat scrub.
Therefore, mitigation for loss of these sensitive natural communities is required.
Land Cover Types and Vegetation Communities
Land cover types and vegetation communities were mapped within the project site boundary. These land cover types and vegetation communities are shown on Figure 4.4-5 and discussed in detail below.
California Buckwheat Scrub (Eriogonum fasciculatum Shrubland Alliance) Approximately 2.85 acres of California buckwheat scrub was mapped within the BSA. California buckwheat scrub (Eriogonum fasciculatum shrubland alliance) occurs on upland slopes, arroyos experiencing intermittent flooding, channels and washes. This alliance occurs on course, well drained soils that are moderately acidic to slightly saline (CNPS, 2022a, b). California buckwheat is the dominant species of this mapped land cover. This observed scrub community is best characterized as Diegan coastal sage scrub described in the Preliminary Descriptions of the Terrestrial Communities of California (Holland 1986). In A Manual of California Vegetation Second Edition (Sawyer et al., 2009), this species assemblage meets the membership rules for the Eriogonum fasciculatum shrubland alliance (California buckwheat scrub).
Sawyer et al. describes California buckwheat scrub as a community that is a nearly pure stand of California buckwheat. Weeds and other coastal sage scrub shrubs occur, but in low densities. The shrub canopy is continuous to intermittent. The herbaceous layer is variable. This community is usually one of the first of the coastal scrubs to establish in mechanically disturbed areas, such as road cuts or slope failures, and it persists in areas with light to moderate grazing.
California buckwheat scrub has been designated by NatureServe as a secure (G5 and S5) natural community. Secure communities are common, widespread, and abundant in the state.
This community is considered low priority for inventory by CDFW and is not considered sensitive (CDFW, 2022c; CNPS, 2022a, b; NatureServe, 2022a).
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Figure 4.4-5
LAND COVER TYPES
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However, California buckwheat scrub is considered a sensitive and protected vegetation community when found to support special status (listed) species, such as the California gnatcatcher (CDFW, 2022c; CNPS, 2022a, b).
California Buckwheat Scrub, Disturbed (Eriogonum fasciculatum Shrubland Alliance) There are approximately 1.54 acres of disturbed California buckwheat scrub in the BSA. This mapped land cover is as described above. However, this land cover exists in a disturbed state because it contains areas that have been altered due to human activities resulting in significant soil compaction and reduction in habitat quality.
Onsite areas given the designation of “disturbed” indicate that more than 20 percent of the given polygon consists of non-native or invasive species, but did not meet the criteria to meet the membership rules for other non-native vegetation communities, such as upland mustards/star thistle fields. In its disturbed state, this vegetation community is considered of moderate to low habitat quality.
This community is considered low priority for inventory by CDFW and is not considered sensitive (CDFW, 2022c; CNPS, 2022a, b).
However, California buckwheat scrub is considered a sensitive and protected vegetation community when found to support special-status (listed) species, such as the California gnatcatcher (CDFW, 2022c; CNPS, 2022a, b).
California Sagebrush – Black Sage Scrub (Artemisia californica - Salvia mellifera Shrubland Alliance)
Approximately 4.86 acres of California sagebrush – black sage scrub was identified in the BSA.
California sagebrush – black sage scrub is characterized by the co-dominance of both California sagebrush and black sage with a 30 to 60 percent relative cover in the shrub canopy. This community is typically found on steep east- to southwest-facing slopes in soils that are usually colluvial (CNPS,2022c). At the project site, the understory ground cover is dominated by leaf litter, with low cover of non-native grass and forb species near the canopy's drip line.
This community is categorized as apparently (S4 and G4), which describes natural communities that are at moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors.
This community is not considered sensitive by CDFW (CDFW, 2022c; CNPS, 2022a, b).
However, California sagebrush – black sage scrub is considered a sensitive and protected natural community when found to support special status (listed) species, such as the California gnatcatcher (CDFW, 2022c; CNPS, 2022a, b, NatureServe, 2022a).
California Walnut Groves (Juglans californica Forest & Woodland Alliance) Approximately 31.01 acres of California walnut groves was identified within the BSA. Mature California black walnut trees are the dominant and most prevalent tree species in the BSA, in some areas reaching 100 percent cover. California walnut trees occur primarily in slope depressions and swales on southern facing slopes and throughout northern facing slopes. California walnut groves 7145/San Dimas MCTA 20-0005 Page 4.4-36
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are characterized by the dominance of California black walnut in densities of greater than 50 percent of relative cover in the tree canopy layer or 30 percent relative cover if codominant with coast live oak (CNPS, 2022a, b). The canopy in this vegetation community varies from open to continuous and the shrub layer consists of sparsely distributed herbs and grasses. California black walnut can reach a height of up to 30 feet and stands occur in association with annual grassland, mesic chaparral, coastal sage scrub, oak woodland, and riparian vegetation (CNPS, 2022a, b).
This community is categorized by NatureServe as vulnerable (G3 and S3.2), which are natural communities that are at moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. considered sensitive by CDFW (CDFW, 2022c, NatureServe, 2022a).
California Walnut Groves, Disturbed (Juglans californica Forest & Woodland Alliance) Approximately 4.10 acres of disturbed California walnut groves was identified in the BSA. This mapped land cover is as described above. However, this land cover exists in a disturbed state because it contains areas that have been altered by human activities resulting in significant soil compaction and reduction in habitat quality. California black walnut is the dominant canopy species of this mapped land cover. The canopy in this vegetation community varies from open to continuous and the shrub layer consists of sparsely distributed herbs and grasses. California black walnut can reach a height of up to 30 feet and stands occur in association with annual grassland, mesic chaparral, coastal sage scrub, oak woodland, and riparian vegetation (CNPS, 2022a, b).
Onsite areas given the designation of “disturbed” indicate that more than 20 percent of the given polygon consists of non-native or invasive species, but did not meet the criteria to meet the membership rules for other non-native vegetation communities, such as upland mustards/star thistle fields. In its disturbed state, this vegetation community is considered of moderate to low habitat quality. If found to support listed species it would be protected as sensitive, with compensatory mitigation likely assigned a reduced ratio.
This community is categorized by NatureServe as vulnerable (G3 and S3.2), which describes natural communities that are at moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors (NatureServe, 2022a). This community is considered sensitive by CDFW (CDFW, 2022c).
Coast Live Oak Woodland and Forest, Disturbed (Quercus agrifolia Forest & Woodland Alliance)
Approximately 3.54 acres of coast live oak woodland was identified in the BSA. Coast live oak woodland is characterized by the dominance of coast live oak in densities of greater than 50 percent of relative cover in the tree canopy layer (CNPS, 2022a, b). The understory in this vegetation community is typically sparse to intermittent and the herbaceous layer consists of sparsely distributed herbs, due to the natural mulch dropped by the oak trees that can inhibit germination of plant seedlings. Coast live oaks can reach a canopy height of 30 meters, but usually vary from nine to 22 meters (Sawyer et al., 2009; Barbour and Minnich 2000). Canopy coverage varies between continuous to open. Shrub cover is occasional or common with the ground layer varying from grassy to absent (Sawyer et al. 2009). Woodlands may intergrade with grasslands such that shrub cover becomes diminished and herbaceous cover can reach 80 percent (Holland and Keil 1995; Barbour and Minnich 2000; CNPS, 2022a, b).
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This community is considered vulnerable (G3 and S3) which describes natural communities that are at moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors; this community is considered sensitive (CDFW, 2022c; NatureServe, 2022a).
Coast Prickly Pear Scrub (Opuntia littoralis - Opuntia oricola - Cylindropuntia prolifera Shrubland Alliance)
Approximately 3.85 acres of coast prickly pear scrub was identified in the BSA. Coast prickly pear scrub is characterized by the dominance of coastal prickly pear in densities greater than 50 percent of relative cover in the shrub canopy layer or greater than 30 percent if sage scrub species, such as California buckwheat, are co-dominant. The canopy is intermittent or continuous; the herbaceous layer is open to continuous and diverse. This community is typically found on south-facing slopes and headlands in shallow loam and clay soils that may be rocky (CNPS, 2022a, b). Coast prickly pear is the dominant species of this mapped land cover. This community is categorized as vulnerable (S3 and G4), which describes natural communities that are at moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors.
This vegetation community is considered sensitive by CDFW. (CDFW, 2022c, NatureServe, 2022a).
Developed/Ornamental
Approximately 25.28 acres of the developed/ornamental land cover type occurs in the BSA. includes areas that often support man-made structures such as houses, sidewalks, buildings, parks, water tanks, flood control channels and transportation infrastructure (streets, bridges and culverts), as well as turf lawns and other landscaped areas containing non-native, ornamental plant species. Within the BSA, the Developed/Ornamental land cover type comprises single-family residential homes and associated paved surfaces such as roadways and driveways, utility structures, and landscaped gardens and yards with ornamental trees and plants.
This land cover type is not considered sensitive by CDFW (CDFW, 2022c; NatureServe, 2022a).
Pepper tree groves (Schinus [molle, terebinthifolius] - Myoporum laetum Forest & Woodland Semi-Natural Alliance)
Approximately 0.81 acre of Pepper tree or Myoporum groves (Schinus [molle, terebinthifolius] - Myoporum laetum Forest & Woodland Semi-Natural Alliance (Pepper tree groves) occurs on the project site. This semi-natural alliance is characterized by the dominance of Myoporum laetum, Schinus molle or Schinus terebinthifolius in the tree canopy; shrubs can occur infrequently or commonly (CNPS, 2022a, b). In the BSA, this vegetation community is dominated by the non-native Peruvian pepper tree, which is currently assigned a limited rating on the California Invasive Plant Inventory (Cal IPC, 2022). See Appendix C, Biological Resources Evaluation for defined Cal-IPC ratings and criteria for the rating system.
This vegetation community is not considered sensitive by CDFW (CDFW, 2022c). 7145/San Dimas MCTA 20-0005 Page 4.4-38
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Upland Mustards or Star-Thistle Fields (Brassica nigra - Centaurea [solstitialis, melitensis] Herbaceous Semi-Natural Alliance)
Approximately 10.89 acres of upland mustards or star-thistle fields (upland mustard fields) were identified in the BSA in senesced, post-fruiting, “mature” condition. Upland mustard fields are characterized by the dominance of black mustard, short-podded mustard, or other mustards occurring with non-native plants in densities greater than 80 percent of relative cover in the herbaceous layer; cover is open to continuous. This community is typically found on fallow fields, rangelands, grasslands, roadsides, levee slopes, disturbed coastal scrub, riparian areas, cleared roadsides, waste places in clay to sandy loam soils (CNPS, 2022a, b).
This vegetation community is not considered sensitive by CDFW (CDFW, 2022c, NatureServe, 2022a).
Upland Mustards or Star-Thistle Fields, Mowed (Brassica nigra - Centaurea [solstitialis, melitensis] Herbaceous Semi-Natural Alliance)
Approximately 16.71 acres of upland mustards or star-thistle fields (Upland mustard fields) were identified in the BSA in a manicured “mowed” condition. Mowed areas are generally associated with fire clearance (fuel modification) requirements within 200 feet of dwelling structures. Upland mustard fields are characterized by the dominance of black mustard, short-podded mustard, or other mustards occurring with non-native plants in densities greater than 80 percent of relative cover in the herbaceous layer; cover is open to continuous. This community is typically found on fallow fields, rangelands, grasslands, roadsides, levee slopes, disturbed coastal scrub, riparian areas, cleared roadsides, waste places in clay to sandy loam soils (CNPS, 2022a, b).
This vegetation community is not considered sensitive by CDFW (CDFW, 2022c, NatureServe, 2022a).
Direct impacts to vegetation communities have immediate consequences, such as the changes that occur when land is cleared for permanent development and vegetation communities are altered or removed during project activities. Direct permanent impacts include all areas within the limits of activities on project sites. Appendix C, Biological Resources Evaluation (BRE) provides the approximate acreages of each plant community and non-vegetated feature that is anticipated to be directly impacted by project activities. Calculations were based on existing APNs (not including conservation easements) in conjunction with vegetation mapping from field surveys and aerial imagery (see Appendix C, BRE Figure 10, Land Cover Types Impact Areas Overview and Figures 10a through 10e, Land Cover Impacts).
A species may have other sensitive designations in addition to their federal or state listing. Coast live oak woodland and forest, and California walnut groves found on a project site are considered as locally and regional rare, unique and/or uncommon; and/or regionally rare vegetation communities; that is, communities that are rare or uncommon in a local or regional context and, as such, would meet the CEQA definition of a rare species (CEQA § 15380). The loss of onsite populations of coast live oak woodland and forest and California walnut groves would be potentially significant from a project and cumulative perspective under CEQA.
Indirect impacts to vegetation communities result in secondary consequences and are likely to be temporary. Indirect impacts could occur to vegetation communities within areas located adjacent to project sites. Examples of indirect, temporary impacts include the effects of fugitive dust and mud 7145/San Dimas MCTA 20-0005 Page 4.4-39
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splatter created by construction activities. Construction-generated fugitive dust and mud splatter can adversely affect vegetation communities by settling on plant surfaces and inhibiting metabolic processes such as photosynthesis and respiration. Construction-related erosion, runoff, siltation, sedimentation, soil compaction, and alteration of drainage patterns could affect vegetation communities by altering conditions within the BSA such that they become unsuitable for survival of these communities.
Implementation of a project could result in indirect impacts to the coast live oak woodland and forest and California walnut groves communities onsite through alteration of drainage patterns which alter the quantity of available water (via stormwater) to these communities; loss of vertical and horizontal structural complexity; and loss of understory species diversity. Indirect impacts to coast live oak woodland and forest and to California walnut groves meet or exceed significance thresholds and are considered significant.
Mitigation Measures
Implementation of a project pursuant to the proposed MCTA could result in direct and indirect impacts to sensitive vegetation communities (see Table 4.4-2). These impacts to sensitive vegetation communities would be significant; therefore, mitigation measures are required.
Implementation of BIO-1, Vegetation Community Replacement Plan, would require projects to either avoid areas of protected sensitive vegetation communities, including California walnut groves, coast live oak woodland and forest, coast prickly pear scrub, California sagebrush-black sage scrub, and/or California buckwheat scrub If these communities cannot be avoided, then, mitigation measure BIO1 would require projects to provide compensatory mitigation for impacted vegetation communities in the form of mitigation bank credits or the payment of in-lieu fees to a mitigation bank.
In addition to protecting sensitive vegetation communities designated by CDFW, mitigation measure BIO-1 may also serve to satisfy the requirements of the City of San Dimas tree protection ordinances (§§ 16.42.020, 16.42.090, 18.162.060, 18.162. 070, and 18.162.100) as mandated by the City’s required tree removal permit for Mature Significant Trees (see MM BIO-18).
Mitigation measure BIO-2, Project Limits and Designated Areas, will specify the limits of ground and vegetation disturbance or removal, and ensure that project-related work limits are delineated and clearly visible to work crews; work crews will be restricted to working within these limits, as described in Section 7.2.
Mitigation Measure BIO-3, General Vegetation and Wildlife Avoidance, will require that removal of native vegetation shall be avoided or minimized to the maximum extent possible. Temporarily impacted areas shall be returned to pre-existing contours and revegetated with appropriate native species.
Level of Significance with Mitigation Incorporated
Direct and indirect impacts to sensitive vegetation communities designated by CDFW would occur as a result of project activities pursuant to the proposed MCTA 20-0005. Implementation of mitigation measures BIO-1, BIO-2, and BIO-3 would minimize or avoid potential impacts to special-status vegetation communities, such as California walnut groves, coast live oak woodland and forest, coast prickly pear scrub, California sagebrush-black sage scrub, and/or California buckwheat scrub within 7145/San Dimas MCTA 20-0005 Page 4.4-40
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the property of an applicant, requiring compensatory mitigation, delineating work areas, and restoring temporarily impacted areas.
Projects would have substantial adverse effects to sensitive natural communities (see Appendix C1, Lot-Specific Impacts) however, with implementation of mitigation measure BIO-1, BIO-2, and BIO3, potential impacts would be less than significant. 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? Less than Significant Impact with Mitigation Incorporated UltraSystems biologists reviewed aerial imagery and data from the USFWS National Wetlands Inventory (NWI) to identify natural and man-made drainages (rivers, streams, creeks), open water (lakes, ponds, etc.), and other features that may be subject to federal or state jurisdictional authority within the BSA (i.e., waters of the U.S. and State, including wetlands; see Figure 4.4-6). They also reviewed USGS 7.5-Minute Topographic Map for the San Dimas Quadrangle to identify potential presence or absence of waterways within the BSA.
The BSA contains NWI-mapped features including freshwater forested/shrub wetlands, riverine areas, and forested/shrub riparian areas, as well as data from the National Hydrography Dataset (NHD). During the survey, evidence of hydrologic features such as streams, wetlands, and ponds were evaluated. During the biological surveys, UltraSystems biologists observed hydrologic features including vegetated riverine wetlands (e.g., riparian areas); additional potential drainages were also mapped using topographic maps. These features are shown on Figure 4.4-6. Based on these reviews, the biologists identified multiple potential waters of the U.S. and/or State within the BSA.
Potential Impacts to Waters of the U.S. and/or State
Direct impacts to waters of the U.S. and State (including, but not limited to, wetlands, ephemeral and intermittent streams, water quality, water quantity and availability, and aquatic/riparian habitat) have immediate consequences, such as the changes that occur when land is cleared and graded for permanent development and waters of the U.S. and State are altered or permanently filled in during project activities. Examples of potential direct impacts which could destroy or significantly impact water features include any ground-disturbing activities, such as grading, clearing, disking, grubbing, excavation, trenching, paving, or compacting that would permanently remove or alter water features.
Other examples of potential direct impacts to water features include filling, stockpiling, channelization, bank stabilization, road crossings, or other permanent drainage modification.
Indirect impacts to water features, water quality, water quantity and availability, and aquatic/riparian habitat result in secondary consequences and are likely to be temporary during project activities, but they could also be long-term as a result of the introduction of impervious surfaces and permanent development. Indirect impacts from implementation of the proposed MCTA could occur within areas adjacent to a project site, including conservation easements, and eventually within downstream areas and receiving waters (e.g., Walnut Creek). Construction-related pollutants including the accidental release of hazardous materials, fugitive dust and siltation/sedimentation, as well as erosion, increased runoff, and soil compaction could adversely affect water features, water quality, water quantity and availability, and aquatic/riparian habitat. Alteration of drainage patterns could affect downstream water features, plants, and habitat by redirecting water flow and runoff to new areas.
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Figure 4.4-6
BIOLOGICAL CONSTRAINTS
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The BSA contains waters of the U.S. and State; water which drains from the site into gutters or storm drains ultimately discharge into Walnut Creek. Project implementation would have significant direct and indirect impacts to water features, water quality, water quantity and availability, and aquatic/riparian habitat both within the BSA and in receiving waters, such as Walnut Creek. Projects pursuant to the proposed MCTA 20-0005 may have significant impacts to waters of the U.S. and State, including wetlands; therefore, mitigation is required.
Mitigation Measures
MM BIO-17: Jurisdictional Delineation Survey and Report Applicants of grading permits pursuant to the proposed MCTA would be required to contract with an authorized biologist to conduct a jurisdictional delineation assessment on their property to determine the presence and extent of potential waters of the U.S. or State (including but not limited to wetlands, ephemeral and intermittent drainages, and associated vegetation communities) that would be subject to the jurisdictional authority of the United States Army Corps of Engineers (USACE), the California State Water Resources Control Board (SWRCB, as represented by the Los Angeles RWQCB), and CDFW. If the assessment determines that the subject property may contain waters of the U.S. or State, a jurisdictional delineation survey is required.
Upon completion of the survey, waters of the U.S or State, if present on the applicant’s property, would be mapped and described in a jurisdictional delineation report that meets or exceeds the report standards of the USACE, Los Angeles District office. The report would include a determination of potential impacts to waters of the U.S. or State (including associated vegetation communities) that would result from the applicant’s project, quantify the area (in acres and square feet) of impacts to waters under the jurisdiction of each agency, and provide a list of permits, authorizations, and agreements required by the applicant from each agency. The report would also recommend impact avoidance and/or minimization measures and best management practices, and compensatory mitigation, as applicable.
Level of Significance with Mitigation Incorporated
The literature search and field surveys determined that the BSA contains waters of the U.S. and State, including riverine and riparian areas. The City of San Dimas, pursuant to § VI(D)(8) of the MS4 permit, will require the implementation of an effective combination of erosion and sediment control BMPs to prevent erosion and sediment loss, and impacts to water quality including those resulting from the discharge of construction wastes within the planning area and to receiving waters (e.g., Walnut Creek).
With regard to the significance criterion for jurisdictional areas, the project is anticipated to result in substantial adverse effect to waters under the jurisdiction of USACE, CDFW, RWQCB; however, implementation of mitigation measure BIO-17 will minimize or avoid impacts to waters of the U.S. and State (including aquatic and riparian habitat), and impacts would be less than significant. d) Would the project interfere substantially with the movement of any resident or migratory fish or wildlife species or with established resident or migratory wildlife corridors, or impede the use of wildlife nursery sites? 7145/San Dimas MCTA 20-0005 Page 4.4-43
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Less Than Significant Impact with Mitigation Incorporated A wildlife corridor is a connection of habitat, generally native vegetation, which joins two or more larger areas of similar habitat that are otherwise separated by natural barriers, changes in vegetation composition, or land permanently altered for human activities (e.g., parks, cemeteries), and by infrastructure, including roads, railroads, residential development, or fencing. When native vegetation is cleared, fragmented patches of open space or isolated “islands” of wildlife habitat are created. Fragmentation and habitat loss are the two main contributors to continuing biodiversity decline. The main goal of corridors is to facilitate movement of individuals, through dispersal, seasonal migration, and movement for foraging, breeding, cover, etc. Corridors allow for physical and genetic exchange between isolated wildlife populations and are critical for the maintenance of ecological processes, including allowing for the movement of animals and the continuation of viable populations and higher species diversity.
Wildlife corridors may either be contiguous strips of vegetation and habitat, such as ridgelines or riverbeds, or intermittent patches of habitat or physical features spaced closely enough to allow safe travel. Corridors can be natural, such as a riparian corridor, or man-made, such as culverts, tunnels, drainage pipes, walls, underpasses, overpasses, or streets. Man-made corridors are often referred to as “wildlife crossings” and they allow wildlife to pass over, under, or through physical barriers that otherwise hinder movement. Wildlife corridors also vary greatly in size, shape, and composition.
The BSA does not overlap with CDFW Essential Connectivity Areas, Natural Landscape Blocks, or other wildlife corridors. The nearest Small Natural Area is Via Verde Park, less than 0.75-mile east of the BSA; the nearest Natural Landscape Block is approximately 1.5 miles east of the BSA at Frank G.
Bonelli Regional Park (CDFW, 2022a; see Figure 4.4-7). The Angeles National Forest, approximately five miles north of the BSA, is the nearest Essential Connectivity Area (Google Earth Pro, 2022; CDFW, 2022a).
Due to the urbanization of the region, movement of some mammals that require larger dispersal distances would likely be deterred. Species that are less restricted in movement and/or are welladapted to urbanized areas such as raccoon, skunk, coyote, and mountain lion (Puma concolor) likely move through areas of the BSA. The project area and a portion of the BSA support habitat, including movement habitat, for species on a local scale (habitat for reptiles, bird, and mammal species), and likely facilitates wildlife movement for some larger wildlife species on a regional scale.
Predators (e.g., coyotes) and smaller mammals (e.g., raccoons [Procyon lotor] and striped skunks [Mephitis mephitis]) are known to use medium- to low-density residential neighborhoods, golf courses, and washes for hunting and foraging, using washes (natural and channelized), culverts, underpasses, and city streets for travelling, often but not necessarily limited to overnight hours when human activity decreases (Baker and Timm, 1998). Urban areas provide a unique ecosystem with ecological opportunity in the form of anthropogenic food sources such as discarded human food, pet food, human-associated fruits, and domestic animals (Larson et. al., 2020). Observations recorded during the biological surveys, including the coyote observed on the BSA, and examination of aerial imagery indicate that the BSA acts as a hunting, foraging, and movement area, and the BSA and surrounding areas are suitable wildlife movement corridors. 7145/San Dimas MCTA 20-0005 Page 4.4-44
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Figure 4.4-7
CDFW WILDLIFE CORRIDORS
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A review of aerial imagery and observations recorded during the biological surveys, including the coyote observed on the BSA, and examination of aerial imagery indicate that the BSA acts as a hunting, foraging, and movement area, and the BSA and surrounding areas are suitable wildlife movement corridors. Additionally, the BSA supports habitat for bat maternity roosts and hibernacula.
Direct impacts to wildlife corridors and crossings occur as a result of loss of cover and hunting or foraging habitat for wildlife species utilizing these areas. Direct impacts to bat maternity roosts and hibernacula occurs when trees and vegetation are cleared, removing suitable habitat for maternity roosts and hibernation sites.
Indirect impacts to wildlife corridors occur when vegetation removal results in fragmented patches of open space or isolated “islands” of wildlife habitat. Because wildlife corridors facilitate movement of individuals through dispersal, seasonal migration, and movement for foraging, breeding, and cover, corridors allow for physical and genetic exchange between isolated wildlife populations and are critical for the maintenance of ecological processes, including allowing for the movement of animals and the continuation of viable populations and higher species diversity.
Indirect impacts to bat maternity roosts and hibernacula occur when removal of vegetation reduces available habitat for insects, reptiles, and small mammal species which in turn reduces the available area for hunting and foraging.
Increased lighting and level of human activity would result in indirect impacts to both wildlife corridors and bat maternity roost and hibernacula.
Increased lighting and level of human activity would result in indirect impacts to both wildlife corridors and bat maternity roost and hibernacula.
Wildlife corridors and native wildlife nursery sites are anticipated to be impacted as a result of project activities. Because Small Natural Areas occur on all sides of the planning area and a Natural Landscape Block (i.e., Frank G. Bonelli Regional Park) is located approximately 1.5 miles east of the planning area, the loss of open space and vegetation within the planning area, combined with the loss of habitat for bat maternity roosts and hibernacula, would be a potentially significant impact; therefore, mitigation is required.
Mitigation Measures
To minimize or avoid impacts to wildlife corridors, bat maternity roosts, and hibernacula, mitigation measures BIO-1, BIO-2, BIO-3, BIO-11, and BIO-16 will be implemented to minimize or avoid removal of native vegetation and other habitat. Implementation of these mitigation measures would preserve valuable resources essential to wildlife corridors, bat maternity roosts, and hibernacula, and preserve native vegetation and habitat which supports hunting and foraging areas.
Implementation of mitigation measure BIO-11 will identify existing maternity roost or hibernacula minimize or avoid impacts to them by safely evicting non-breeding bats, establishing avoidance buffers, or replacing roosts at a suitable location.
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Level of Significance with Mitigation Incorporated
The literature review and field surveys determined that the planning area functions as a wildlife corridor and potentially contains native wildlife nursery sites (e.g., bat maternity roosts). With implementation of mitigation measures BIO-1, BIO-2, BIO-3, BIO-11, and BIO-16, impacts to wildlife corridors and native wildlife nursery sites would be less than significant. e) Would the project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? Less than Significant Impact with Mitigation Incorporated The Chapter 18.62 Tree Preservation Ordinance of the San Dimas Municipal Code states the goal of protecting and preserving mature significant trees, as well as “other trees which are determined to be desirable”. The Tree Preservation Ordinance defines a mature significant tree as follows:
Any tree within the city of an oak genus which measures eight inches or more in trunk diameter, and/or any other species of tree that measures ten inches or more in trunk diameter, and/or any multi-trunk tree(s) having a total circumference of thirty-eight inches or more; the multitrunk tree shall include at least one trunk with a diameter of a minimum of four inches.
Removal or relocation of mature significant trees must be approved by the director of development services or the development plan review board. Section 18.162.020 defines removal to include:
Any act which will cause a mature significant tree to die, including but not limited to acts which inflict damage upon the root system or other parts of the tree by fire, cutting, application of toxic substances, operation of equipment or machinery, or by changing the natural grade of land by excavation or filling the drip line area around the trunk.
Future removal or relocation of mature significant trees must be approved by the director of development services or the development plan review board. This approval is subject to conditions as deemed necessary to implement the provisions of the ordinance. No protected tree shall be removed or otherwise destroyed unless a tree removal permit has been approved by the director.
The BSA supports many mature significant trees which, due to their trunk diameter and/or total circumference of combined trunks, would require a tree removal permit as per the ordinance (see Appendix C, Biological Resources Evaluation for a full discussion of this ordinance).
The removal of the existing protected trees on a project site would cause direct impacts as a result of construction of the project. Other direct impacts to trees scheduled for preservation is that grounddisturbing construction activities such as grading, disking, excavating, soil compaction, and operation of heavy equipment could damage lateral tree roots that extend beyond the tree protection zone.
Potential indirect impacts to mature significant trees on a project site include increased dust levels.
Dust generated during project activities may have indirect impacts to the preservation of protected trees. Dust can coat the leaves throughout a tree’s canopy and reduce the tree’s ability to conduct photosynthetic processes necessary for growth and survival.
Removal of mature significant trees within individual project sites pursuant to the proposed MCTA 20-0005 would be potentially significant (see Section 4.4[b]), and mitigation would be required. 7145/San Dimas MCTA 20-0005 Page 4.4-47
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Mitigation Measures
To minimize impacts to the root system or other parts of protected trees, mitigation measure BIO18 will be implemented in Lots 1 through 36 (see Table 4.4-2); BIO-18, Mature Significant Tree Protection Measures, requires mitigation for trees permitted by the City for removal.
Mitigation measure BIO-1 will also be implemented as described in Section 4.4(b).
MM BIO-18: Mature Significant Tree Protection Measures
There are numerous trees in the project areas that are designated as “mature significant trees” as per the City’s tree preservation ordinance. Refer to Section 3.3.2 of the BRE (Appendix C) for an expanded discussion of the tree ordinance.
Prior to the issuance of a grading permit, in accordance with the tree preservation ordinance, a certified arborist will conduct a complete tree inventory of the project site and adjacent areas within the property of the applicant, including conservation easements. The tree inventory will include the location, species, estimated height, canopy dripline (estimate if inaccessible), health, and diameter(s) (see measurement requirements below). Transplantable saplings will also be noted.
Measurements. The trunk diameter must be measured at a point thirty-six inches above the ground at the base of the tree. Mature significant trees include:
• Any tree of the Genus Quercus (oak) measuring greater than eight inches or more in trunk diameter, and/or
•
•
Any other species of tree that measures ten inches or more in trunk diameter, and/or Any multi-trunk tree(s) having a total circumference of thirty-eight inches or more; the multitrunk tree shall include at least one trunk with a diameter of a minimum of four inches.
The ordinance also requires that no significant trees shall be removed or relocated on an undeveloped area of a property without first submitting an arborist report and obtaining a tree removal permit from the City’s Development Services, Planning Division.
The arborist report will incorporate the aforementioned tree inventory criteria, as well as provisions for disease management using best available management practices including: (1) treated infected trees before removing them from the project site; (2) cleaning and disinfecting all pruning and power tools before and after use to prevent the introduction and/or spread of pathogens; (3) and irrigation avoidance within oak tree canopies. Recommendations for onsite and/or offsite replanting methods will be provided. It is suggested that the City require replanting efforts to mimic the surrounding landscape and avoid separate landscape tree plantings as replacement, which do not meet the definition of CEQA for appropriate mitigation to less than a significant level.
Section 18.162.060 Conditions Imposed of the Tree Preservation Ordinance:
• Tree relocation and/or two for one replacement with minimum fifteen-gallon box tree(s), or other replacement of equivalent value and size, within the subject property. The two for one replacement ratio may be reduced as determined by the final decision-making body, if a minimum of one of the following additional findings are made: (1) The reduced replacement requirement is consistent with the purposes of this chapter, (2) the tree(s) in question are located where the impact of the tree removal on the community is limited (such as trees in a 7145/San Dimas MCTA 20-0005 Page 4.4-48
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generally flat portion of the rear yard of a single-family house that are deemed to have less public benefit).;
•
•
When on-site features, project constraints, and/or other considerations exist which prevent reasonable on-site relocation, relocation to an approved off-site location shall be permitted; If said conditions are imposed, the owner will be responsible for all replacement and relocated trees for a minimum period of two years. If during this time the tree(s) is (are) declared unhealthy by a certified arborist as set forth in Section 18.162.090, the diseased trees shall be removed and replaced at the cost of the applicant, as set forth in Section 18.162.100 • A maintenance agreement shall be submitted by the applicant and established for each replaced and relocated tree. The maintenance agreement and maintenance responsibility shall be transferred with the sale of the property if title to the property is transferred within the specified maintenance period. (Ord. 1165 § 4, 2006))
If approved by the City, compensatory mitigation may occur through a fee payment into a local mitigation bank and/or through development and implementation of an HMMP (see BIO-1).
Replanting may occur onsite or offsite (within the reserved open space conservation easement) as “restoration/rehabilitation” and/or “enhancement.”.” The conservation easement must allow for habitat restoration activities if available as an option. The replacement plantings will be planted to mimic the surrounding natural habitat in an effort to retain the functions and values per each treedominated vegetation community. Individual disjointed plantings will be avoided to the maximum extent feasible, in an effort to maintain or prevent net loss of the existing surrounding landscape.
Upon City approval, BIO-1 may fully mitigate for BIO-18, This mitigation will satisfy the City’s Tree Preservation and Protection ordinance (Municipal Code Chapter 106.39) and will ensure equal or superior ecological viability as required in the FEIR, General Plan, and as per CEQA § 21081.6 Findings or Negative Declarations; Reporting or Monitoring Project Changes; Effect on Environment; Conditions.
Level of Significance with Mitigation Incorporated
Potential project impacts to protected trees that are not covered by the City of San Dimas Tree Removal Permit would be impacted during project-related activities. Implementing mitigation measures BIO-1 and BIO-18 will minimize the significant impacts to protected and mature significant trees to a less than significant level.
f) Would the project conflict with the provisions of an adopted Habitat Conservation Plan, Natural Communities Conservation Plan, or other approved local, regional, or state habitat conservation plan?
No Impact
The East San Gabriel Valley Significant Ecological Area (SEA) is located in the easternmost portion of the San Gabriel Valley, which includes the San Jose Hills (see Figure 4.4-8). The area represents several ridgelines and hilltops and a major drainage at the eastern end of the San Jose Hills which have been surrounded by urban development over the past four decades. The largest component of this SEA is Frank G. Bonelli Regional County Park (Bonelli Park) and a portion of Walnut Creek Park. 7145/San Dimas MCTA 20-0005 Page 4.4-49
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Figure 4.4-8
SIGNIFICANT ECOLOGLICAL AREAS (SEAs)
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Components of the East San Gabriel SEA are within approximately 0.5-mile of the BSA; however, the BSA does not intersect with nor is it immediately adjacent to these SEA components.
The BSA is located less than 1.5 miles from designated critical habitat for the coastal California gnatcatcher within and surrounding Frank G. Bonelli Regional Park (see Figure 4.4-9). Additionally, the BSA is less than one mile north of designated critical habitat for coastal California gnatcatcher which is mapped along the south-facing slopes of the San Jose Hills from northwest of the I-10/SR57 Interchange to Highway 39 (Azusa Avenue) in West Covina. However, the BSA is not located within or adjacent to this critical habitat.
No direct or indirect impacts to critical habitat are anticipated as a result of construction of the project.
Mitigation Measures
Critical habitat is not anticipated to be significantly impacted; therefore, no mitigation measures are required.
Level of Significance
Neither the East San Gabriel SEA nor critical habitat within the vicinity of the BSA are anticipated to be impacted by implementation of the proposed MCTA; therefore, no impact will occur. 7145/San Dimas MCTA 20-0005 Page 4.4-51
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Figure 4.4-9
USFWS CRITICAL HABITATS
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4.5 Cultural Resources
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
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
X
X
archaeological resource pursuant to
§ 15064.5?
c) Disturb any human remains,
including those interred outside of
formal cemeteries?
X
4.5.1 Methods
A cultural resources analysis was conducted for the San Dimas Municipal Code Amendment 20-005 project site (refer to Figure 4.5-1) that included a California Historic Resources Inventory System (CHRIS) records and literature search at the South Central Coastal Information Center (SCCIC) located at California State University, Fullerton for cultural resources in the project boundary and the
0.5-mile radius on March 9, 2022. Additionally, a request was made to the Native American Heritage Commission (NAHC) to conduct a search of its Sacred Lands File (SLF) for potential traditional cultural properties as well as to provide a list of local Native American tribes and tribal representatives to contact. Finally, a pedestrian survey of the project boundary was completed on August 9, 2022. The SCCIC records search was conducted prior to conducting the pedestrian survey.
The NAHC request was made on February 28, 2022, and a reply was received on April 15, 2022; letters were sent to the listed tribes on April 17, 2022 (see Attachment C in Appendix D).
4.5.2 Existing Conditions
Based on the cultural resources records search, it was determined that no historic cultural resources or prehistoric archeological sites have been previously recorded within the project site boundary.
Within the 0.5-mile buffer zone, there was one previously recorded prehistoric cultural resource but no historic-era archaeological sites have been recorded. No historic or prehistoric resources were observed during the field survey.
7145/San Dimas MCTA 20-0005 Page 4.5-1
Initial Study/Mitigated Negative Declaration Page 1085 – 2053 December 2022 ❖ SECTION 4.5 – CULTURAL RESOURCES ❖
Figure 4.5-1
TOPOGRAPHIC MAP
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.5 – CULTURAL RESOURCES ❖
4.5.3 a)
Analysis of Impacts
Would the project cause a substantial adverse change in the significance of a historical resource pursuant to § 15064.5?
Less than Significant Impact with Mitigation Incorporated A historical resource is defined in § 15064.5(a)(3) of the CEQA Guidelines as any object, building, structure, site, area, place, record, or manuscript determined to be historically significant or significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California. Historical resources are further defined as: being associated with significant events, important persons, or distinctive characteristics of a type, period or method of construction; representing the work of an important creative individual; or possessing high artistic values. Resources listed in, or determined eligible for, the California Register of Historical Resources (CRHR), included in a local register, or identified as significant in a historic resource survey are also considered as historical resources under CEQA.
Similarly, the National Register of Historic Places (NRHP) criteria (contained in 36 CFR 60.4) are used to evaluate resources when complying with Section 106 of the National Historic Preservation Act (NHPA). Specifically, the NRHP criteria state that eligible resources comprise districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association, and that: (a) are associated with events that have made a significant contribution to the broad patterns of our history; or (b) that are associated with the lives of persons significant in our past; or (c) that embody the distinctive characteristics of a type, period, or method of construction, or that possess high artistic values, or that represent a significant distinguishable entity whose components may lack individual distinction; or (d) that have yielded, or may be likely to yield, information important to history or prehistory.
A substantial adverse change in the significance of a historical resource as a result of a project or development is considered a significant impact on the environment. Substantial adverse change is defined as physical demolition, relocation, or alteration of a resource or its immediate surroundings such that the significance of the historical resource would be materially impaired. Direct impacts are those that cause substantial adverse physical change to a historic property. Indirect impacts are those that cause substantial adverse change to the immediate surroundings of a historic property, such that the significance of a historical resource would be materially impaired.
The cultural resources records search conducted at the SCCIC determined that five historic-era resources have been recorded within a 0.5-mile radius of the area of potential effect (APE) of the project boundary (Table 1.3-1 in Appendix D), but none of them has been recorded within the APE.
All of the sites are historic and the majority are residential sites.
According to records at the SCCIC, two previous cultural resource surveys have included a portion of the project area, and 21 surveys have been conducted within the 0.5-mile radius project buffer but not within the project APE (Appendix D).
As a result of the field survey, no historic buildings were identified within the project site. No other cultural resources were observed during the survey. Therefore, it is unlikely that historical and archaeological resources would be adversely affected by construction of the project. However, grading activities associated with development of the project would cause new subsurface disturbance and may result in the unanticipated discovery of unique historic and/or prehistoric 7145/San Dimas MCTA 20-0005 Page 4.5-3
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archeological resources. In the event of an unanticipated discovery, implementation of mitigation measures CUL-1 and CUL-2 described below would ensure that impacts on historical and archaeological resources would be less than significant.
Mitigation Measure
MM CUL-1 Prior to the commencement of grading or excavation, workers conducting construction activities and their foremen will receive Worker Environmental Awareness Program (WEAP) training from a qualified archaeologist regarding the potential for sensitive archaeological and paleontological resources to be unearthed during grading activities. The workers will be directed to report any unusual specimens of bone, stone, ceramics or other archaeological artifacts or features observed during grading and/or other construction activities to their foremen and to cease grading activities in the immediate vicinity of the discovery until a qualified archaeologist or Native American cultural monitor is notified of the discovery by the Superintendent of the project site and can assess their significance. The WEAP shall be implemented to educate all construction personnel of the area’s environmental conditions and the environmental protection measures that must be adhered to by all workers throughout the duration of project construction.
Training materials shall be language-appropriate for all construction personnel. Upon completion of the WEAP, workers shall sign a form stating that they attended the program, understand all protection measures, and shall abide by all the rules of the WEAP. A record of all trained personnel shall be kept with the construction foreman at the project field construction office and shall be made available to any resource agency personnel. If new construction personnel are added to the project later, the construction foreman shall ensure that new personnel receive training before they start working. The archaeologist shall provide hard copies of the WEAP presentation to the construction foreman.
MM CUL-2 If historical or unique archaeological resources are discovered during construction, the contractor shall halt construction activities in the immediate area and notify the City. An on-call qualified archaeologist shall be notified and afforded the necessary time to recover, analyze, and curate the find(s). A Monitoring and Treatment Plan shall be prepared by the qualified archaeologist. The qualified archaeologist shall recommend the extent of archaeological monitoring necessary to ensure the protection of any other resources that may be in the area and afforded the necessary time and funds to recover, analyze, and curate the find(s). Construction activities may continue on other parts of the site while evaluation and treatment of historical or unique archaeological resources takes place.
Level of Significance After Mitigation
With implementation of mitigation measures CUL-1 and CUL-2 above, potential impacts related to historical and archaeological resources would be less than significant. b) Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to § 15064.5?
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Less than Significant Impact with Mitigation Incorporated An archaeological resource is defined in § 15064.5(c) of the CEQA Guidelines as a site, area or place determined to be historically significant as defined in § 15064(a) of the CEQA Guidelines, or as a unique archaeological resource defined in § 21083.2 of the Public Resources Code as an artifact, object, or site that contains information needed to answer important scientific research questions of public interest or that has a special and particular quality such as being the oldest or best example of its type, or that is directly associated with a scientifically recognized important prehistoric or historic event or person. The level ground surface elevation relative to adjacent roads suggests that the ground on the project site has been minimally disturbed, with the native surface soil remaining. It is unlikely that undisturbed unique archeological resources exist on the project site as determined by the cultural resources investigation conducted by UltraSystems, which included a CHRIS records search of the project site and 0.5-mile radius, a search of the SLF by the NAHC, and a pedestrian field survey.
The cultural resources records search conducted at the SCCIC determined that there is one known prehistoric cultural resource site recorded within a 0.5-mile radius of the project boundary (Table
1.3-1 in Appendix D). The records search revealed that are no historic resources recorded within
0.5-mile of the project site.
A NAHC SLF search was conducted on and within a 0.5-mile radius around the project site. The NAHC provided a response letter dated April 15, 2022, which stated that there is a record documenting the presence of traditional cultural properties within this area, and to contact the Gabrielino Band of Mission Indians – Kizh Nation for more information.
The NAHC also provided UltraSystems with a list of local Native American tribes (including the Gabrielino Band of Mission Indians – Kizh Nation) and specific tribal representatives to contact regarding this project. Subsequently, nine representatives of the seven Native American tribes were contacted with a letter requesting a reply if they have knowledge of cultural resources in the area that they could provide, and asking if they had any questions or concerns regarding the project. The contacted tribes are:
•
•
•
Gabrieleno Band of Mission Indians –
Kizh Nation
Gabrieleno/Tongva San Gabriel Band
of Mission Indians
Gabrielino Tongva Indians of
California Tribal Council
•
•
•
•
Gabrielino/Tongva Nation
Gabrielino-Tongva Tribe
Santa Rosa Band of Cahuilla Indians
Soboba Band of Luiseno Indians
As noted in Section 4.5.1, letters were sent to the nine representatives of seven Native American tribal organizations, including a note to the Gabrielino – Kizh Nation asking about the SLF site. There were no direct responses to the letter and subsequent emails. (refer to Appendix D of this IS/MND).
Four telephone calls were placed on July 22, 2022, with no answer and messages left describing the project and requesting a response. These calls were to Andrew Salas, Chairperson of the Gabrielino – Kizh Nation; Sandonne Goad, Chairperson of the Gabrielino/Tongva Nation; Charles Alvarez, Councilmember of the Gabrielino-Tongva Tribe; and to Lovina Redner, Tribal Cahir of the Santa Rosa Band of Cahuilla Indians.
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Chairperson Anthony Morales, of the Gabrieleno/Tongva San Gabriel Band of Mission Indians indicated by telephone on July 22, 2022 that the footprint of the SR-57 and I-10 Freeway are sensitive to the tribe. There are sites at nearby Cal Poly Pomona to the east and Bonelli Park. They recommend tribal and archaeological monitoring using their tribe. Tribal Consultant and Administrator Christina Conley, of the Gabrielino Tongva Indians of California Tribal Council, indicated by telephone on July 22, 2022 that the tribe has no comment on the project and will leave any comments to their sister tribes. Joseph Ontiveros, of the Cultural Resource Department for the Soboba Band of Luiseño Indians indicated by telephone on July 22, 2022 that there are resources in the area that have place names, including sites at Bonelli Park and Cal Poly Pomona campus. The tribe would defer any comments to Chairman Anthony Morales of the San Gabriel Band of Mission Indians. No further responses have been received to date. (See Attachment C in Appendix D.) The result of the pedestrian survey was negative for both prehistoric and historic sites and isolates on the project site. Based on the results of the records search and the onsite field survey, it is unlikely that cultural resources or tribal resources would be adversely affected by construction of the project.
However, grading activities associated with development of the project would cause new subsurface disturbance and may result in the unanticipated discovery of unique historic and/or prehistoric archeological resources. In the event of an unanticipated discovery, implementation of mitigation measure MM CUL-2 described above would ensure that impacts on archeological resources would be less than significant.
Level of Significance After Mitigation
With implementation of mitigation measures CUL-1 and CUL-2 above, potential impacts related to archaeological resources would be less than significant. c) Would the project disturb any human remains, including those interred outside of formal cemeteries?
Less than Significant Impact with Mitigation Incorporated As previously discussed in Section 4.5.3-b above, the project would be built on an area where the much of the land that the amendment would allow to be graded is undisturbed slopes, with native surface that has not been previously graded. No human remains have been previously identified or recorded onsite. It is unlikely that undisturbed unique archaeological resources exist on the project site. The project proposes grading activities for the implementation of infrastructure that includes water, sewer and utility lines. Grading and trenching activities associated with development of the project would cause new subsurface disturbance and could result in the unanticipated discovery of unknown human remains, including those interred outside of formal cemeteries. In the unlikely event of an unanticipated discovery, implementation of mitigation measure CUL-3 and adherence to applicable codes and regulations would ensure that impacts related to the accidental discovery of human remains would be less than significant.
California Health and Safety Code § 7050.5 identifies procedures for the discovery of human remains.
CEQA § 15064.5 indicates the process for determining the significance of impacts on archaeological and historical resources. California Public Resources Code § 5097.98 stipulates the notification process during the discovery of Native American human remains, descendants, disposition of human remains, and associated artifacts.
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Mitigation Measure
MM CUL-3 If human remains are encountered during excavations associated with this project, all work shall stop within a 30-foot radius of the discovery and the County Coroner shall be notified (§ 5097.98 of the Public Resources Code). The Coroner shall determine whether the remains are recent human origin or older Native American ancestry. If the coroner, with the aid of the supervising archaeologist, determines that the remains are prehistoric, they shall contact the NAHC. The NAHC shall be responsible for designating the Most Likely Descendant (MLD). The MLD (either an individual or sometimes a committee) shall be responsible for the ultimate disposition of the remains, as required by § 7050.5 of the California Health and Safety Code. The MLD shall make recommendations within 24 hours of their notification by the NAHC. These recommendations may include scientific removal and nondestructive analysis of human remains and items associated with Native American burials (§ 7050.5 of the Health and Safety Code).
Level of Significance After Mitigation
With implementation of mitigation measure CUL-3 above, potential impacts related to human remains would be less than significant.
7145/San Dimas MCTA 20-0005 Page 4.5-7
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4.6 Energy
Less than
Significant
Impact with
Mitigation
Potentially
Significant
Impact
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
a) Result in 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?
X
X
4.6.1 Existing Conditions
Electricity
Electricity is supplied to the project site by Southern California Edison (SCE), which provides electricity to the City of San Dimas (Karen Warner Associates, 2013a, p. II-5). SCE provides electricity to the project site from existing electrical service lines.
Natural Gas
Natural Gas is supplied to the project site by SoCalGas, which provides natural gas to the City of San Dimas (Karen Warner Associates, 2013a, p. II-5).
4.6.2 a)
Impact Analysis
Would the project result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation?
Less than Significant Impact
According to the CEQA Guidelines, “uses of nonrenewable resources during the initial and continued phases of the project may be irreversible since a large commitment of such resources makes removal or nonuse thereafter unlikely. Primary impacts and, particularly, secondary impacts (such as highway improvement that provides access to a previously inaccessible area) generally commit future generations to similar uses. Also, irreversible damage can result from environmental accidents associated with the project. Irretrievable commitments of resources should be evaluated to assure that such current consumption is justified.” (CEQA Guidelines § 15126.2[d]) Therefore, the purpose of this analysis is to identify any significant irreversible environmental effects of project implementation that cannot be avoided.
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Construction
The following forms of energy are anticipated to be expended during construction:
•
•
•
Diesel fuel for off-road equipment (gallons).
Electricity to deliver water for use in dust control (kilowatt-hours [kWh]).
Motor vehicle fuel for worker commuting, materials delivery and waste disposal (gallons).
Electricity
During project construction, energy would be consumed in the form of electricity associated with the conveyance and treatment of water used for dust control and, on a limited basis, powering lights, electronic equipment, or other construction activities necessitating electrical power.
Due to the fact that electricity usage associated with lighting and construction equipment that utilizes electricity is not easily quantifiable or readily available, the estimated electricity usage during project construction is speculative.
Lighting used during project construction would comply with Title 24 standards/requirements (such as wattage limitations). This compliance would ensure that electricity use during project construction would not result in the wasteful, inefficient, or unnecessary use of energy. Lighting would be used in compliance with applicable City of San Dimas Municipal Code requirements to create enough light for safety.
Natural Gas
Construction activities, including the construction of new buildings and facilities, typically do not involve the consumption of natural gas. Therefore, the proposed project is not anticipated to have a demand for natural gas during project construction.
Transportation Energy
Project construction would consume energy in the form of petroleum-based fuels associated with the use of off-road construction vehicles and equipment on the project site, construction workers’ travel to and from the project site, and delivery and haul truck trips hauling solid waste from and delivering building materials to the project site.
During project construction, trucks and construction equipment would be required to comply with the California Air Resources Board’s (ARB’s) anti-idling regulations. ARB’s In-Use Off-Road Diesel-Fueled Fleets regulation would also apply (ARB, 2016). Vehicles driven to or from the project site (delivery trucks, construction employee vehicles, etc.) are subject to fuel efficiency standards requirements established by the federal government. Therefore, project construction activities regarding fuel use would not result in wasteful, inefficient, or unnecessary use of energy.
Operation
The project consists of expanding the allowable grading (cut and fill) on each of the 36 residential lots in the project site by 1,000 cubic yards (cy) per lot, increasing from 35,000 cy to 36,000 cy.
Energy would be consumed during project operations related to space, water conveyance, and vehicle trips of construction equipment. Project operation energy usage, which was estimated by 7145/San Dimas MCTA 20-0005 Page 4.6-2
Initial Study/Mitigated Negative Declaration Page 1093 – 2053 December 2022 ❖ SECTION 4.6 – ENERGY ❖
CalEEMod as part of the greenhouse gas emissions analysis (refer to Section 4.8) is shown in Table
4.6-1.
Table 4.6-1
ESTIMATED PROJECT OPERATIONAL ENERGY USE
Energy Type Units Value Daily
Onroad Motor Vehicle Travel
(gasoline/diesel use)
Natural Gas Use
Gallons gasoline/year
Gallons diesel/year
1,000 BTU per year
44,589
3,630
917,715
282,886
122
10 2,514
Electricity Use Kilowatt-hours per year 775
Sources: Onroad Motor Vehicle Fuel Consumption calculated by UltraSystems using EMFAC2021(v1.0.2) emissions inventory web platform tool (ARB, 2022) and CalEEMod (2020.4.0) (CAPCOA, 2022); see Appendix E.
Natural Gas Use and Electricity Use calculated by UltraSystems with CalEEMod (2020.4.0) (CAPCOA, 2022).
The proposed project would install energy-efficient features. Insulated and glazed windows and low E coating on windows, would be incorporated into building design. Additionally, the proposed project would adhere to applicable federal, state, and local requirements for energy efficiency, including Title 24 standards. The proposed project would not result in the inefficient, wasteful, or unnecessary consumption of building energy. Additionally, there would not be any inefficient, wasteful, or unnecessary energy usage in comparison to similar development projects of this nature regarding construction-related fuel consumption. Therefore, the implementation of the proposed project would result in less than significant impacts on energy resources.
Continued use of energy resources is consistent with the anticipated growth within the city and the general vicinity and would not result in energy consumption requiring a significant increase in energy production for the energy provider. Therefore, the energy demand associated with the project would be less than significant.
b) Would the project conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
Less Than Significant Impact
Title 24
The proposed project would be in compliance with the California Green Building Standards (CAL Green) Code (California Code of Regulations, Title 24, Part 11), which includes mandatory measures for nonresidential site development, energy efficiency, water efficiency and conservation, material conservation and resource efficiency, and environmental quality.
City of San Dimas General Plan
Section III, 2014-2021 Housing Element, of the City of San Dimas, states that the City has adopted the latest version of the California Code of Regulations, Title 24, along with all required updates. The City has adopted the State 2010 Green Building Code Standard’s within its Municipal Code (Karen Warner Associates, 2013b, p. III-14). The City has completed a greenhouse gas inventory (GHG), and in 2010 adopted an Energy Efficiency & Conservation Strategy which identifies a series of projects to help the City save energy and reduce GHGs (Karen Warner Associates, 2013c, p. V-4). 7145/San Dimas MCTA 20-0005 Page 4.6-3
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The proposed project would adhere to applicable federal, state, and local requirements for energy efficiency, including California Code of Regulations Title 24 standards and the City of San Dimas General Plan. Therefore, impacts would be less than significant. 7145/San Dimas MCTA 20-0005 Page 4.6-4
Initial Study/Mitigated Negative Declaration Page 1095 – 2053 December 2022 ❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
4.7 Geology and Soils
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
a) Directly or indirectly cause potential
substantial adverse effects, including
the risk of loss, injury, or death
involving:
i) Rupture of a known earthquake
fault, as delineated on the most
recent Alquist-Priolo Earthquake
Fault Zoning Map issued by the
State Geologist for the area or
based on other substantial
X
evidence of a known fault? Refer
to Division of Mines and Geology
Special Publication 42.
ii) Strong seismic ground shaking? X
X
X
iii) Seismic-related ground failure,
including liquefaction?
iv) Landslides?
b) Result in substantial soil erosion or
the loss of topsoil? X
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 onor 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?
X
X
e) Have soils incapable of adequately
supporting the use of septic tanks or
alternative waste water disposal
systems where sewers are not
available for the disposal of waste
water?
X
f) Directly or indirectly destroy a
unique paleontological resource or
site or unique geologic feature?
X
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The project would result in an increase in allowable grading under the Municipal Code. Grading conducted pursuant to such increase is addressed below. The project does not propose development of land uses; thus, impacts caused by operation of land uses are not addressed below. a) Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:
i) Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42.
Less than Significant Impact
The Alquist-Priolo Zones Special Studies Act defines active faults as those that have experienced surface displacement or movement during the last 11,650 years (i.e., during the Holocene Period).
The project site is located in the seismically active region of Southern California; however, no AlquistPriolo Earthquake Hazard Zones and no active faults are mapped in or near the project site. (See Figure 4.7-1.) The nearest Alquist-Priolo Earthquake Hazard Zone to the project site is approximately
6.5 miles to the northwest along the Sierra Madre Fault Zone. The nearest mapped active fault to the project site is the Duarte Fault, approximately 4.6 miles to the northwest (CGS, 2022). In addition, the project does not propose development of structures for human occupancy. Project implementation would not cause hazards arising from surface rupture of a known active fault, and no impacts would occur.
ii) Strong seismic ground shaking?
Less than Significant Impact with Mitigation Incorporated The two nearest faults to the project site are the Walnut Creek Fault, approximately 0.5 mile to the north, and the San Jose Fault about 1.5 miles to the south (CGS, 2022; see Figure 4.7-2.) Both the Walnut Creek Fault and the San Jose Fault are known, active earthquake faults.
The project proposes an increase in permissible grading; due to the slopes present within the project site the proximity of the Walnut Creek Fault and the San Jose Fault, applicants for grading permits authorized by the proposed MCTA would be required to obtain site-specific studies as described in mitigation measures GEO-1 and GEO-2.
GEO-1 Preliminary Soil Report. Expansion of grading, as permitted by the MCTA, would require a preliminary soil report, prepared by a civil engineer who is registered by the state. The report would be based upon adequate test borings or excavations as described in §§ 1803.1.1.1 through 1803.1.1.5 of the 2022 (or current) California Building Code.
Soil classification would be based on observation and any necessary tests of the materials disclosed by borings, test pits or other subsurface exploration made in appropriate locations. Additional studies would be made as necessary to evaluate slope stability, soil strength, position and adequacy of load-bearing soils, the effect of moisture variation on soil-bearing capacity, compressibility, liquefaction and expansiveness. The Preliminary Soil Report would provide best management practices for grading and construction and measures to minimize or avoid damage to human life and 7145/San Dimas MCTA 20-0005 Page 4.7-2
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property due to erosion or slope failure resulting from weak soils or seismic shaking, compression, liquefaction, and expansion.
GEO-2 Geotechnical Investigations. Due to the proximity of active earthquake faults, expansion of grading, as permitted by the MCTA, would require a geotechnical investigation prepared by a geotechnical engineer who is registered by the state. The geotechnical investigation would be conducted in accordance with §§ 1803.3 through 1803.7 of the 2022 (or current) California Building Code.
The geotechnical investigation would include but not be limited to:
•
•
•
•
Slope instability Liquefaction
Total and differential settlement
Surface displacement due to faulting or seismically induced lateral spreading or lateral flow The potential for liquefaction and soil strength loss evaluated for site peak ground acceleration, earthquake magnitude and source characteristics consistent with the maximum considered earthquake ground motions.
An assessment of potential consequences of liquefaction and soil strength loss including, but not limited to, the following:
•
•
•
Lateral soil movement
Lateral soil loads on foundations
Increases in soil lateral pressures on retaining walls.
The geotechnical investigation report would include provide measures designed to mitigate potential hazards resulting from seismic activity
With implementation of mitigation measures GEO-1 and GEO-2, implementation of the proposed MCTA would not cause substantial hazards arising from strong ground shaking, and impacts would be less than significant and no additional mitigation would be required. 7145/San Dimas MCTA 20-0005 Page 4.7-3
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Figure 4.7-1
ALQUIST PRIOLO FAULT ZONES
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
Figure 4.7-2
REGIONALLY ACTIVE FAULTS
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
iii) Seismic-related ground failure, including liquefaction? Less Than Significant Impact with Mitigation Incorporated Liquefaction is the sudden decrease in the strength of cohesionless soils due to dynamic or cyclic shaking. Saturated soils behave temporarily as a viscous fluid (liquefaction) and consequently lose their capacity to support the structures built on them. The potential for liquefaction decreases with increasing clay and gravel content but increases as the ground acceleration and duration of shaking increase. Liquefaction potential has been found to be the greatest where the groundwater level and loose sands occur within 50 feet of the ground surface.
No geotechnical investigation report for the entire project site is available. Geotechnical investigation reports for two properties within the project site are mentioned here referencing examples of conditions onsite. A geotechnical investigation reports for 1532 Calle Cristina determined that that property is underlain by colluvium (soil and rock fragments that have slid to the base of a cliff or slope) underlain by Puente Formation bedrock consisting of thin beds of siltstone interbedded with thin beds of sand (Quartech, 2015). A geotechnical investigation report for 1533 Calle Cristina found the site to be underlain by 12 to 18 inches of loose, dry, disced fill soil underlain by Puente Formation siltstone (Nicoll, 2014). Groundwater was not identified in borings in 1532 Calle Cristina to depths of approximately 35 feet below ground surface (bgs), or in test pits in 1533 Calle Cristina to depths of up to 6 feet bgs (Quartech, 2015; Nicoll, 2014).
Mitigation measure GEO-2 would require a geotechnical investigation for each grading project conducted pursuant to the proposed MCTA. Mitigation measure GEO-2 would assess liquefaction potential in rock and soil under their respective project sites and provide any recommendations needed to minimize risks from liquefaction. Therefore, impacts would be less than significant and no additional mitigation would be required.
iv) Landslides?
Less than Significant Impact with Mitigation Incorporated The project site is on the crest and upper slopes of a small ridge in the San Jose Hills. Much of the project site is in a zone of required investigation for earthquake-induced landslides mapped by the California Geological Survey (CGS, 2022)- See Figure 4.7-3. Project implementation could cause substantial hazards arising from earthquake-induced landslides.
Mitigation measure GEO-2 would assess the potential for earthquake-induced landslides resulting from the proposed grading and recommend measures to minimize any hazards identified.
Implementation of such recommendations would be required as a condition of a grading permit.
Impacts would be less than significant after compliance with requirements of the City of San Dimas Municipal Code and of grading permits issued by the City. No additional mitigation would be required.
7145/San Dimas MCTA 20-0005 Page 4.7-6
Initial Study/Mitigated Negative Declaration Page 1101 – 2053 December 2022 ❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
Figure 4.7-3
LANDSLIDES AND LIQUEFACTION
7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration
❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
b) Would the project result in substantial soil erosion or the loss of topsoil? Less Than Significant Impact
Construction
Soils on the project site are moderately susceptible to sheet and rill erosion by water, and are moderately susceptible to wind erosion (Soil Survey Staff, 2022). As described in Section 4.10, Hydrology and Water Quality, applicants of grading projects under the proposed MCTA would be required by the City to comply with the Los Angeles County MS4 Permit.
As described in § IV(D)(8)(d) of the MS4 Permit, applicants for grading permits pursuant to the proposed MCTA would be required to implement an effective combination of erosion and sediment control BMPs to prevent erosion and sediment loss prior to commencement of construction activities.
These BMPs must be maintained, inspected before and after each precipitation event, and repaired or replaced as necessary. Because applicants would be required by the MS4 Permit to comply with all applicable conditions of the Construction General Permit, Grading pursuant to the proposed MCTA would involve large-scale soil disturbance, which could cause severe soil erosion if effective erosion-control measures were not used. Grading would also be required to comply with City of San Dimas Municipal Code Chapter 14.11, Stormwater Management and Discharge, Section 14.11.060, Requirements for Construction Projects. Sediment must be retained onsite to the maximum extent practicable; sediment that leaves the site must be removed the same day. Drainage controls—such as detention ponds, dikes, filter berms, ditches, down drains, chutes, or flumes— must be used as needed (QCode, 2022).
Project impacts would be less than significant after compliance with§ IV(D)(8)(d) of the MS4 Permit and relevant San Dimas Municipal Code requirements.
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? Less than Significant Impact with Mitigation Incorporated Impacts of project development arising from liquefaction would be less than significant with implementation of mitigation measures GEO-1 and GEO-2, and no landslide impact would occur, as substantiated above in Sections 4.7.a.iii and 4.7.a.iv, respectively.
Lateral Spreading
Lateral spreading is the rapid downslope movement of surface sediment, in a fluid-like flow, due to liquefaction in a subsurface layer. The analysis for liquefaction in Section 4.7.a.iii above also pertains to lateral spreading. With implementation of mitigation measures GEO-1 and GEO-2, impacts would be less than significant.
Subsidence
The major cause of ground subsidence is the excessive withdrawal of groundwater. With implementation of mitigation measures GEO-1 and GEO-2, impacts would be less than significant. 7145/San Dimas MCTA 20-0005 Page 4.7-8
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Collapse
Collapsible soils consist of loose, dry, low-density materials that collapse and compact with the addition of water or excessive loading. The proposed increase in allowable grading is for grading of backyards. Common uses of backyards such as lawns and gardens would not exacerbate hazards arising from collapsible soils. Any subsequent construction for human occupancy in an affected backyard—for instance, an accessory dwelling unit (ADU)—would be a separate project requiring a geotechnical investigation report, as described in mitigation measure GEO-2, assessing the suitability of rock and soil on that site for supporting that proposed structure; and providing needed recommendations for remedial grading and foundation design. With implementation of mitigation measure GEO-2, impacts would be less than significant.
d) Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property? Less than Significant Impact
Expansive soils shrink and swell with changes in soil moisture. Soil moisture may change from landscape irrigation, rainfall, and utility leakage. Repeated shrinking and expansion may compromise structure foundations. Expansive soils are commonly very fine-grained with high to very high percentages of clay. Expansive soils may be present onsite based on the type of rock underlying the site, including shale (a sedimentary rock composed of clay particles), clay shale, and siltstone. The project does not propose construction of structures for human occupancy. When a homeowner may want to build a paved patio in their backyard, the geotechnical investigation report for grading on that property would provide recommendations for remedial grading and for pavement design. In addition, if a structure meant for human habitation would be proposed, it would require a geotechnical investigation report assessing the suitability of rock and soil on that site for supporting that proposed structure; and providing needed recommendations for remedial grading and foundation design. The analysis addressing subsequent construction projects under Collapse above also applies to expansive soils. With implementation of mitigation measures GEO-1 and GEO-2, impacts would be less than significant.
e) Would the project have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water?
No Impact
The proposed project would not generate wastewater. Thus, no impacts associated with septic tanks or alternative waste water disposal systems would occur. f) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?
Less than Significant Impact with Mitigation Incorporated The project site is underlain by siltstone of the Puente Formation of late Miocene age (Dibblee and Minch, 2002). The Miocene Epoch extends from approximately 23 million to 5.3 million years before present (ybp) to the present (GSA, 2018). A paleontological records search completed by the Natural History Museum of Los Angeles County on February 26, 2022 identified seven vertebrate fossil 7145/San Dimas MCTA 20-0005 Page 4.7-9
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localities in the project region listed in Table 4.7-1 below. The geologic units of the five closest localities are Puente Formation; two of those units are also identified as shale. The remaining two localities are unknown formations of Pleistocene age, one being sand and silt and the other silt. The Pleistocene Epoch extends from approximately 2.58 million to 12,000 ybp (GSA, 2018). Two of the localities are on the ground surface, one at a depth of 30 feet bgs, and the remaining four are at unknown depths.
Table 4.7-1
PALEONTOLOGICAL RECORDS SEARCH RESULTS
Locality
Location Formation Taxa Depth Number
LACM VP
7471
Lot 14 off Calle Amapola Street in
SanDimas
Puente Formation Mola (sunfish;
Molidae)
Unknown
LACM VP
6172
LACM VP
6166
Calle Andrea and S.San Dimas
Avenue
First bike path diverging south
fromVia Verde Road in Bonelli
RegionalCounty Park
Puente Formation
(densetan/yellow shale)
Puente Formation
Fish (Osteichthyes) Unknown
Sturgeonfish Surface
(Prionurus)
LACM VP
6173
LACM VP
6167
LACM VP
3363
Ridge overlooking thesouthwestern Puente Formation(shale) bank ofPuddingstone Reservoir
Extinct bony fish
(Etringus)
Mako shark (Isurus
planus)
Surface
Unknown
Unknown
Puddingstone Dam Puente Formation
W of Monterey Pass Road in Coyote
Pass;E of the Long Beach Freeway
& S of the Nboundary of Section 32;
Monterey Park
Unknown Formation
(Pleistocene; sand and
silt)
Horse (Equus)
LACM VP
7702
Intersection of 26th St
and Atlantic Blvd, Bell Gardens
Unknown Formation
(Pleistocene; silt)
Fish (Gasterosteus);
Snake (Colubridae),
Rodents
30 feet bgs
(Thomomys,
Microtus,
Reithrodontomys);
Rabbit (Sylvilagus)
Source: Los Angeles County Natural History Museum, 2022 Considering the number of fossil localities in the Puente Formation, and specifically Puente Formation shale, grading operations in accordance with the proposed project could damage fossils in Puente Formation rock onsite. Any substantial excavations should be closely monitored to collect any specimens quickly and professionally. In the event of an unexpected discovery, implementation of mitigation measure GEO-1 would ensure paleontological resources or unique geologic features are not significantly affected.
Mitigation Measure
MM GEO-1 Before the beginning of grading pursuant to the proposed project, the grading proponent shall retain a qualified paleontologist to be on-call during the duration of grading. If paleontological resources are uncovered during grading, the contractor shall halt grading in the immediate area and notify the City. The on-call paleontologist shall be notified and afforded the necessary time and funds to recover, analyze, and 7145/San Dimas MCTA 20-0005 Page 4.7-10
Initial Study/Mitigated Negative Declaration Page 1105 – 2053 December 2022 ❖ SECTION 4.7 – GEOLOGY AND SOILS ❖
curate the find(s). Subsequently, the monitor shall remain onsite for the duration of grading to ensure the protection of any other resources that are found.
Level of Significance After Mitigation
With implementation of mitigation measure GEO-1 above, potential impacts related to paleontological resources would be less than significant. 7145/San Dimas MCTA 20-0005 Page 4.7-11
Initial Study/Mitigated Negative Declaration Page 1106 – 2053 December 2022 ❖ SECTION 4.8 – GREENHOUSE GAS EMISSIONS ❖
4.8 Greenhouse Gas Emissions
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
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?
X
X
4.8.1 GHG Constituents
Introduction
Constituent gases that trap heat in the Earth’s atmosphere are called greenhouse gases, analogous to the way a greenhouse retains heat. GHGs play a critical role in the Earth’s radiation budget by trapping infrared radiation emitted from the Earth’s surface, which would otherwise escape into space. Without the natural heat-trapping effect of GHG, the Earth’s surface would be about 34°F cooler. This natural phenomenon, known as the “Greenhouse Effect,” is responsible for maintaining a habitable climate. However, anthropogenic emissions of these GHGs, more than natural ambient concentrations, are responsible for the enhancement of the greenhouse effect, and have led to a trend of unnatural warming of the Earth’s natural climate known as global warming or climate change (CalEPA, 2006).
Greenhouse Gases
GHGs are defined under the California Global Warming Solutions Act of 2006 (AB 32) as carbon dioxide (CO , methane (CH , nitrous oxide (N O), hydrofluorocarbons (HFCs), perfluorocarbons 2) 4) 2 (PFCs) and sulfur hexafluoride (SF6).9 Associated with each GHG species is a “global warming potential” (GWP), which is a value used to compare the abilities of different GHGs to trap heat in the atmosphere. GWPs are based on the heat-absorbing ability of each gas relative to that of CO2, as well as the decay rate of each gas (the amount removed from the atmosphere over a given number of years). Methane (CH ) is estimated to have a GWP of 25 over 100 years. carbon dioxide (CO ) has a 4 2 GWP of 1 and nitrous oxide (N O) has a GWP 298 times that of CO for a 100-year timescale. (USEPA, 2 2 2022d). “Carbon dioxide equivalent” (CO2e) emissions are calculated by weighting each GHG compound’s emissions by its GWP and then summing the products.
Carbon dioxide (CO2) is a clear, colorless, and odorless gas consisting of molecules made up of two oxygen atoms and one carbon atom. Fossil fuel combustion is the main human-related source of CO2 emissions; electricity generation and transportation are first and second in the amount of CO2 emissions, respectively. Carbon dioxide is the basis of GWP, and thus has a GWP of 1. 9 http://www.leginfo.ca.gov/pub/05-06/bill/asm/ab_0001-0050/ab_32_bill_20060927_chaptered.pdf. 7145/San Dimas MCTA 20-0005 Page 4.8-1
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Methane (CH4) is a clear, colorless gas, and is the main component of natural gas. Anthropogenic sources of CH4 are fossil fuel production, biomass burning, waste management, and mobile and stationary combustion of fossil fuel. Wetlands are responsible for most of the natural CH4 emissions (USEPA, 2022e). As mentioned above, within a 100-year period CH4 is 25 times more effective in trapping heat than is CO2.
Nitrous oxide (N O) is a colorless, clear gas, with a slightly sweet odor. N O has both natural and 2 2 human-related sources and is removed from the atmosphere mainly by photolysis or breakdown by sunlight, in the stratosphere. The main human-related sources of N2O in the United States are agricultural soil management (synthetic nitrogen fertilization), mobile and stationary combustion of fossil fuel, adipic acid production, and nitric acid production. Nitrous oxide is also produced from a wide range of biological sources in soil and water (USEPA, 2019). According to the Intergovernmental Panel on Climate Change (IPCC), within a 100-year span, N2O is 298 times more effective in trapping heat than is CO2 (IPCC, 2007).
4.8.2 Thresholds of Significance
Neither the City, the SCAQMD nor the State CEQA Guidelines Amendments has adopted specific quantitative thresholds of significance for addressing a project’s GHG emissions. Nonetheless, § 15064.4 of the CEQA Guidelines serves to assist lead agencies in determining the significance of the impacts of GHGs. As required in § 15064.4 of the CEQA Guidelines, this analysis includes an impact determination based on the following: (1) an estimate of the amount of GHG emissions resulting from the project; (2) a qualitative analysis or performance based standards; (3) a quantification of the extent to which the project increases GHG emissions as compared to the existing environmental setting; and (4) the extent to which the project complies with regulations or requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions.
The City of San Dimas does not have an adopted threshold of significance for GHG emissions, but for CEQA purposes, it has discretion to select an appropriate significance criterion, based on substantial evidence. To provide guidance to local lead agencies on determining significance for GHG emissions in their CEQA documents, the SCAQMD Board adopted an Interim CEQA GHG Significance Threshold for Stationary Sources, Rules, and Plans (SCAQMD, 2008a). The SCAQMD estimated that a threshold of 3,000 metric tons (MT) of CO2e per year for all non-industrial projects would help subject 90% of all GHG emissions to CEQA analysis (SCAQMD, 2010). The City has selected this value as a significance criterion which has been supported by substantial evidence. a) Would the project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment?
Less Than Significant Impact
Methodology
GHG emissions would come from the construction of the proposed project. Construction of the project would result in temporary emissions of GHGs from fuel combustion by onsite construction equipment and by onroad vehicle traffic (i.e., worker commute and delivery truck trips. Operational emissions were not addressed in this study, because the only activity that will change is the grading of additional land.
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Short-term GHG emissions are those construction emissions that do not recur over the life of the project. The only construction phase in this analysis is grading. Emissions are from offroad construction equipment and on-road travel, such as worker commuting; vendor deliveries; and truck hauling of soil
Other GHG emissions would occur continually after buildout. GHGs are emitted from buildings because of activities for which electricity and natural gas are typically used as energy sources.
Combustion of carbon-based fuel emits CO2 and other GHGs directly into the atmosphere; these emissions are considered direct emissions. The project’s primary direct source of annual GHG emissions will be on-road mobile sources. GHGs are also emitted during the generation of electricity from fossil fuels; when produced offsite, these emissions are indirectly associated with the project.
Indirect GHG emissions also result from the production of electricity used to convey, treat, and distribute water and wastewater. A final indirect GHG emission source is decomposition of organic waste that is generated by the project and transported to landfills.
Temporary construction GHG emissions from the project’s onsite and offsite project activities were calculated using the California Emissions Estimator Model (CalEEMod), Version 2020.4.0 (CAPCOA, 2021). CalEEMod is a planning tool for estimating emissions related to land use projects. To assess the overall lifetime project GHG emissions, the SCAQMD developed an Interim Guidance (SCAQMD, 2008a, p. 3-10) that recommends that construction emissions should be amortized over the life of the project, defined in the guidance as 30 years. Annualized GHG emissions is compared to the applicable interim GHG significance threshold.
Construction
Construction is an episodic, temporary source of GHG emissions. Emissions are generally associated with the operation of construction equipment and the disposal of construction waste. To be consistent with the guidance from the SCAQMD for calculating criteria pollutants from construction activities, only GHG emissions from onsite construction activities and offsite hauling and construction worker commuting are considered as project-generated. As explained by the California Air Pollution Control Officers Association (CAPCOA) in its 2008 white paper (CAPCOA, 2008), the information needed to characterize GHG emissions from manufacture, transport, and end-of-life of construction materials would be speculative at the CEQA analysis level. CEQA does not require an evaluation of speculative impacts (CEQA Guidelines § 15145). Therefore, the construction analysis does not consider such GHG emissions, but does consider non-speculative onsite construction activities, and offsite hauling and construction worker trips. All GHG emissions are identified on an annual basis.
The proposed project includes a Municipal Code Text Amendment (MCTA) of Title 18-Zoning, Chapter 18.518: Specific Plan 11 of the San Dimas Municipal Code, to amend grading limits within Planning Area I and to make various clean-up text amendments. The grading phase involves the use of a mix of construction equipment and has its own distinct GHG emissions characteristics. A “worstcase” scenario, in which all the additional grading would occur during seven months om 2023, was assumed. CalEEMod defaults were used otherwise. Construction emissions occur both onsite and offsite. Onsite air pollutant emissions consist principally of exhaust emissions from offroad heavyduty construction equipment. Offsite emissions result from workers commuting to and from the job site, as well as from vendors and visitors to the site.
CalEEMod estimated construction GHG emissions to be 577.49 MT of CO2e. The 30-year amortized value is 19.25 MT per year. This is below the threshold of 3,000 MT per year and is therefore less than significant.
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b) Would the project conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases?
Less than Significant Impact
City of San Dimas doesn’t include a GHG emissions plan and thus, it relies on the efficient state and regional plans which helps to reduce GHG emissions everywhere, including San Dimas. The Greenhouse Gas Inventory prepared by CTG Energetics, Inc. in 2010, includes the actions by other parties which results in the reduction of GHG emissions (City of San Dimas Greenhouse Gas Inventory, 2010). Therefore, it is assumed to be true for the purpose of estimating the future GHG emissions.
The City of San Dimas GHG Inventory provides information on the activities that cause emissions and removals, as well as background on the methods used to make the calculations. Although it covers a large number of interrelated topics, the following discussion focuses on those aspects that (1) seek to reduce GHG emissions that result from municipal and private sector activities in the city and (2) have potential relevance to the proposed project. The GHG inventory has the following relevant targets in the reduction of GHG emissions and fossil fuels:
State Action Assumptions
California has established a number of mandates that will help reduce GHG emissions by 2020. These actions will reduce fossil fuel combustion and therefore reduce GHG emissions throughout the state, including in San Dimas.
California Renewable Portfolio Standard
•
•
The California Air Resources Board’s (CARB) Adopted Scoping Plan makes it clear that implementation of the Renewable Portfolio Standard (RPS) is a foundational element of the State’s emissions reduction plan.
The scenario with 2020 State mandates considered in this analysis assumes that utilities will reduce the carbon intensity of delivered electricity equivalent to meeting the 33% RPS goal by 2020.
These actions will reduce fossil fuel combustion and therefore reduce GHG emissions.
California Low Carbon Fuel Standard
•
•
In 2007, Executive Order S-1-07 was issued requiring the establishment of a Low Carbon Fuel Standard (LCFS) for transportation fuels. This statewide goal requires that California’s transportation fuels reduce their carbon intensity by at least 10 percent by 2020.
In accordance with the Scoping Plan, this analysis incorporates the modified reduction potential for the LCFS.
These actions will reduce the amount of carbon emitted by fossil fuel combustion and therefore reduce transportation GHG emissions.
Federal Corporate Average Fuel Economy (CAFE) Standards 7145/San Dimas MCTA 20-0005 Page 4.8-4
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•
•
In 2010, the EPA and the Department of Transportation’s National Highway Safety Administration announced new light-duty vehicle greenhouse gas emissions standards and corporate average fuel economy standards.
The EPA forecasts that these standards will reduce GHG emissions from the U.S. light-duty fleet by approximately 21 percent from 2030 business-as-usual.
These actions will reduce fossil fuel combustion and therefore reduce GHG emissions.
Title 24 Code Cycles
•
•
California’s Title 24 Building Energy Code is updated every three years. Due to the implementation of new Title 24 Codes, there will be a reduction in new residential and nonresidential building emissions.
Based on the growth projections provided by San Dimas, the City can expect about 3.5% reduction from total city-wide baseline 2020 emissions due to increasing Title 24 Code updates for residential and nonresidential buildings.
These actions will reduce fossil fuel combustion and therefore reduce GHG emissions.
As was demonstrated in Section 4.11, the proposed project would have no impacts in relation to consistency with local land use plans, policies, or regulations. Therefore, the project would not hinder the GHG emission reductions of the Greenhouse Gas Inventory.
Finally, as noted in Section 3.2.1, allowable grading (cut and fill) on each of the 36 residential lots in the project site would have to comply with the provisions of the California Green Building Code, Title 24, Part 11 of the California Code of Regulations.
Climate change impacts of the project will be less than significant. 7145/San Dimas MCTA 20-0005 Page 4.8-5
Initial Study/Mitigated Negative Declaration Page 1111 – 2053 December 2022 ❖ SECTION 4.9 – HAZARDS AND HAZARDOUS MATERIALS ❖
4.9 Hazards and Hazardous Materials
Less than
Significant
Impact with
Mitigation
Potentially
Significant
Impact
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
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?
X
X
c) Emit hazardous emissions or handle
hazardous or acutely hazardous
materials, substances, or waste
within one-quarter mile of an
existing or proposed school?
X
d) Be located on a site which is included
on a list of hazardous materials sites
compiled pursuant to Government
Code Section 65962.5 and, as a
result, would it create a significant
hazard to the public or the
X
environment?
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?
X
f) Impair implementation of or
physically interfere with an adopted
emergency response plan or X
X
emergency evacuation plan?
g) Expose people or structures, either
directly or indirectly, to a significant
risk of loss, injury or death involving
wildland fires?
The proposed increase in allowable grading would not include development of land uses involving an operations phase. Thus, the analysis in this Section addresses impacts of grading only. 7145/San Dimas MCTA 20-0005 Page 4.9-1
Initial Study/Mitigated Negative Declaration Page 1112 – 2053 December 2022 ❖ SECTION 4.9 – HAZARDS AND HAZARDOUS MATERIALS ❖
a) Would the project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? Less than Significant Impact
Grading pursuant to project approval would involve use of hazardous materials such as lubricants, and greases. Chemical transport, storage, and use would comply with: Resource Conservation and Recovery Act (RCRA); Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA); Occupational Safety and Health Administration (OSHA); California hazardous waste control law; California Division of Safety and Health (DOSH); South Coast Air Quality Management District (SCAQMD), and Los Angeles County Fire Department (LACoFD) requirements. Compliance with applicable laws and regulations would ensure that impacts associated with routine transport, use, or disposal of hazardous materials during grading would be less than significant. 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?
Less than Significant Impact
Grading pursuant to project approval could involve accidental release of hazardous materials. The construction contractor would train construction workers in containment and cleanup of small spills of hazardous materials and would maintain equipment and supplies for such containment and cleanup onsite. In the event of a release of hazardous materials of quantity and/or toxicity that construction workers could not safely contain and clean up, the contractor would notify the LACoFD immediately. Impacts would be less than significant.
c) Would the project emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school?
No Impact
No schools are within 0.25 mile of the project site. Project implementation would not emit hazardous emissions or handle hazardous materials within 0.25 mile of a school, and no impact would occur. d) Would the project be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment? Less than Significant Impact
Government Code § 65962.5 requires the Department of Toxic Substances Control (DTSC) to compile and update, at least annually, lists of the following:
•
•
Hazardous waste and substances sites from the DTSC EnviroStor database.
Leaking Underground Storage Tank (LUST) sites by county and fiscal year in the State Water Resources Control Board (SWRCB) GeoTracker database.
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• Solid waste disposal sites identified by SWRCB with waste constituents above hazardous waste levels outside waste management units.
•
•
SWRCB Cease and Desist Orders (CDOs) and Cleanup and Abatement Orders (CAOs).
Hazardous waste facilities subject to corrective action pursuant to § 25187.5 of the Health and Safety Code, identified by DTSC.
These lists are collectively referred to as the “Cortese List” (CalEPA, 2020). The project site is not listed in the Cortese List and there would be no impacts (CalEPA, 2020).
Two hazardous materials sites are listed within 0.5 mile of the project site on the GeoTracker database maintained by the State Water Resources Control Board:
• Forest Lawn Memorial Park, 21300 Via Verde Drive, Covina, 950 feet south of the project site:
leaking underground storage tank (LUST) released gasoline affecting drinking water aquifer; case closed 1996.
• Forest Lawn Memorial Park, 21300 Via Verde Drive, Covina, 1,050 feet southeast of the project site: LUST released gasoline affecting soil; case closed 2007 (SWRCB, 2022).
Neither of those sites are considered environmental concerns for the proposed project due to the downgradient elevation of the sites and because both cases are closed. Project implementation would not create substantial hazards to the public or the environment related to hazardous materials sites included on the Cortese List, and impacts would be less than significant. 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?
No Impact
The closest public airport is Brackett Field in the City of La Verne, approximately 2.8 miles to the northeast. As shown in Figure 4.9-1, the project site is outside of land use compatibility zones and noise contours for Brackett Field (LACALUC, 2022). Therefore, project development would not expose people residing or working in the project area to a hazard or excessive noise levels associated with airports and no impact would occur.
f) Would the project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?
Less than Significant Impact
The emergency operations plan in effect for the City of San Dimas is the Los Angeles County Operational Area Emergency Response Plan (“ERP”) approved by the County Board of Supervisors in 2012. The ERP identifies County agencies and other agencies that would be involved in emergency responses, threat summaries and assessments, and procedures for responding agencies as well as County agencies that would be involved in coordinating and managing responses. The ERP is focused on emergencies beyond the scope of the daily functions of public safety agencies, such as emergencies 7145/San Dimas MCTA 20-0005 Page 4.9-3
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Figure 4.9-1
BRACKETT FIELD AIRPORT INFLUENCE AREA
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requiring multi-agency and/or multi-jurisdictional responses (LACOA, 2012).
Construction
Grading in accordance with the proposed project would be conducted within residential parcels and would not extend into roadways. Grading operations would not use public roadways for staging of construction equipment or soil, in concurrence with City of San Dimas Department of Public Works, Engineering Division requirements. Project implementation would not interfere with an emergency response plan, and impacts would be less than significant. g) Would the project expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires? Less than Significant Impact
The project site is in a Very High Fire Hazard Severity Zone in a Local Responsibility Area—that is, an area where local jurisdictions are responsible for the costs of wildfire prevention and suppression—mapped by the California Department of Forestry and Fire Protection, as shown in Figure 4.9-3 (CAL FIRE, 2022). A State Responsibility Area abuts the south project site boundary, as shown in Figure 4.9-2. The project site and abutting land to the north and south are a mix of residential uses and vacant land. However, land surrounding the project site is built out with urban uses. Three historical wildfires are mapped within the project site on maps maintained by CAL FIRE.
•
•
•
Puente Fire, 1971, burned 165 acres
Covina Hills Road Fire, 1976, burned 191 acres
Via Verde Fire, 1972, burned 10 acres (CAL FIRE, 2022).
Implementation of the proposed increase in allowable grading is minimal and typically would not involve development of structures for human occupancy. Thus, project implementation would not expose people or structures to substantial wildfire risks, and impacts would be less than significant. 7145/San Dimas MCTA 20-0005 Page 4.9-5
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Figure 4.9-2
FIRE HAZARD SEVERITY ZONE – STATE RESPONSIBILITY AREA
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Figure 4.9-3
FIRE HAZARD SEVERITY ZONE – LOCAL RESPONSIBILITY AREA
7145/San Dimas MCTA 20-0005 Page 4.9-7
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4.10 Hydrology and Water Quality
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
a) Violate any water quality standards or
waste discharge requirements or
otherwise substantially degrade surface
or ground water quality?
X
X
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 offsite;
(ii) substantially increase the rate or
amount of surface runoff in a manner
which would result in flooding on- or
offsite;
X
X
(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
X
(iv) impede or redirect flood flows? X
X
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?
X
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a) Would the project violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality? Less than Significant Impact
Planning Area 1 (PA1; project) is located within the southwestern portion of the City and is located within Specific Plan 11. The majority of PA1 has been developed with single-family residences within hillside areas and is surrounded by existing hillside single-family residences. Local access to PA1 is provided by Via Verde and regional access is provided by the San Bernardino Interstate-10 (I-10) Freeway, approximately 1 mile to the south. PA1 generally drains into a storm drain system on Calle Cristina and connects via an underground storm drainage system to Walnut Creek Wash. Walnut Creek Wash is a tributary of the San Gabriel River.
Runoff from the Project discharges to Walnut Creek Wash (State Waterbody ID:
CAR4053100019980918112433). This 303(d) impaired waterbody is part of the larger USGS San Gabriel Watershed (HUC 18070106) [USGS, 2013]. Water quality impairments from Walnut Creek Wash near PA1 were considered when selecting the pollutants of concern for this water quality analysis. CWA Section 303(d) Listings for the Walnut Creek Wash impairments include benthicmacroinvertebrate toxicity bioassessments, indicator bacteria, and pH.
Impacts related to water quality would occur during three different periods: (1) during the earthwork and construction phase, when the potential for erosion, siltation, and sedimentation would be the greatest; (2) following construction, prior to the establishment of ground cover in the landscaped areas, when the erosion potential may remain relatively high; and (3) following completion of the project, when impacts related to sedimentation would diminish, but those associated with urban runoff would increase.
Construction Pollutant Controls
The project owners would be required by the California State Water Resources Control Board (SWRCB) to obtain coverage under a General Permit for Discharges of Storm Water Associated with Construction Activity (Construction General Permit Order 2009-0009-DWQ, as authorized by § 402 CWA for projects which will disturb one or more acres of soil during construction). The Construction General Permit requires potential dischargers of pollutants into waters of the U.S. to prepare a site-specific Stormwater Pollution Prevention Plan (SWPPP), which establishes enforceable limits on discharges, requires effluent monitoring, designates reporting requirements, and requires construction BMPs to reduce or eliminate point and non-point source discharges of pollutants.
The project would be required to obtain an Construction General Permit, prepare a SWPPP, and implement construction stormwater BMPs prior to commencement of construction activities.
Additionally, BMPs must be maintained, inspected before and after each precipitation event, and repaired or replaced as necessary. Because the project is required by the SWRCB to comply with all applicable conditions of the Construction General Permit, potential violations of water quality standards or waste discharge requirements during project construction would be less than significant.
For projects that would disturb less than one acre of soil, applicants for grading permits pursuant to the proposed MCTA would be required to comply with the Waste Discharge Requirements for Municipal Separate Storm Sewer System (MS4) Discharges within the Coastal Watersheds of Los 7145/ San Dimas MCTA 20-0005 Page 4.10-2
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Angeles County (except those discharges originating from the City of Long Beach MS4), Order No. R4- 2012-0175 as amended by State Water Board Order WQ 2015-0075 and Los Angeles Water Board Order R4-2012-0175-A01 NPDES Permit No. CAS004001 (referred to as the MS4 Permit), to which the City of San Dimas is a Permittee. The MS4 Permit the discharge of pollutants from anthropogenic sources into waters of the U.S. through stormwater and urban runoff conveyance systems, including flood control facilities (e.g., storm drains)
Section IV(D)(8)(d)(1) of the MS4 applies to construction sites of less than one acre, and requires the implementation of an effective combination of erosion and sediment control BMPs to prevent erosion and sediment loss. Sections IV(D)(8)(e ) and IV(D)(8)(f) of the MS4 require operators of public and private construction sites within its jurisdiction to select, install, implement, and maintain BMPs that comply with its erosion and sediment control ordinance, and state that the requirements contained in this part apply to all activities involving soil disturbance with the exception of agricultural activities.
Activities covered by this permit include but are not limited to grading, vegetation clearing, soil compaction, paving, re-paving and linear underground/overhead projects. Grading projects of less than one acre would, with compliance with the Los Angeles County MS4 Permit, minimize or avoid potential violations of water quality standards or waste discharge requirements, and would not substantially degrade surface or groundwater quality.
Applicants for grading permits pursuant to the proposed MCTA would be required to comply with § IV(D)(8)(d) of the MS4 Permit, which requires construction best management practices (BMPs) to reduce or eliminate point and non-point source discharges of pollutants, including sediment.
Additionally, BMPs must be maintained, inspected before and after each precipitation event, and repaired or replaced as necessary. Potential violations of water quality standards or waste discharge requirements during project construction would be less than significant.
Operational Pollutant Controls
As new development and redevelopment occurs, it can significantly increase pollutant loads in stormwater and urban runoff, because increased population density results in proportionately higher levels of vehicle emissions, vehicle maintenance wastes, municipal sewage wastes, household hazardous wastes, fertilizers, pet waste, trash, and other anthropogenic pollutants (SWRCB, 2013).
The Los Angeles County MS4 Permit requires new development and significant redevelopment projects to incorporate post-construction low-impact development BMPs into project design. to reduce or eliminate the quantity, and improve the quality of, stormwater being discharged from the project site.
A preliminary Hydrology and Water Quality Technical Report (HWQTR) (Engeo, 2022) has been prepared for the proposed project site and is included herein as Appendix G. The associated HWQTR recommends the implementation of Low Impact Development (LID) features, as presented in the LID Standards Manual (LACDPW, 2014) to ensure that most stormwater runoff is treated and retained onsite.
The project HWQTR includes BMPs, such as erosion control, sediment control, waste and materials management, non-stormwater management, training and education, inspection, maintenance, monitoring, and sampling (Engeo, 2022, pgs. 9-10).
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Compliance with the Los Angeles County MS4 Permit, and with implementation of BMPs recommended by the HWQTR, potential impacts to water quality would be less than significant and mitigation is not proposed.
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?
Less Than Significant Impact
The project site is over the Main San Gabriel Valley Groundwater Basin, which spans approximately 255 square miles in east-central Los Angeles County (DWR, 2022a). Golden State Water Company (GSWC) San Dimas System provides water to the project site. GSWC obtains water supplies from the following sources: imported water from northern California purchased through Three Valleys Municipal Water District (TVMWD); groundwater from the Main San Gabriel Groundwater Basin; treated groundwater and surface water purchased from Covina Irrigating Company; and treated water purchased from Walnut Valley Water District (Stetson Engineers Inc, 2021, p. 6-3). GSWC forecasts that it will have sufficient water supplies to meet demands in its service area over the 2025- 2045 period. Water demand projections are based on growth projections from the Southern California Association of Governments (SCAG), which in turn are based on forecasts according with developments pursuant to general plan land use designations. The proposed project would conform with the existing General Plan land use designation; thus, water use from the proposed project is accounted for in GSWC’s water demand forecast. Project development would not substantially decrease groundwater supplies.
The project site is not used for intentional groundwater recharge, and project development would not interfere with groundwater recharge. Impacts would be less than significant. c) 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:
i) Result in substantial erosion or siltation on- or offsite; Less Than Significant with Mitigation Incorporated
The proposed project site contains multiple slopes in the San Jose Hills. Ephemeral and intermittent drainages were observed throughout the project site during the biological surveys conducted for the project.
As described in Section 4.7, the project site is moderately susceptible to wind and water erosion; erosion may lead to siltation on- or offsite. Potential grading of up to 1,000 cubic yards on individual properties could lead to substantial erosion. Mitigation measure GEO-1, described in Section 4.7(b), would evaluate soils of individual grading sites and assess their potential for erosion. The Preliminary Soil Report would provide best management practices for grading and construction and measures to minimize or avoid erosion that could lead to siltation.
Applicants for grading permits pursuant to the proposed MCTA would be required to comply with § IV(D)(8)(d) of the MS4 Permit which would minimize or avoid wind or water through either wind or water erosion, and thus minimize or avoid soil erosion onsite and siltation in receiving waters. 7145/ San Dimas MCTA 20-0005 Page 4.10-4
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With implementation of mitigation measure GEO-1 and compliance with the MS4 Permit and proper maintenance and replacement of required stormwater BMPs (as necessary), potential impacts resulting in substantial erosion or siltation on- or offsite would be minimized or avoided, and impacts would be less than significant. No additional mitigation is proposed. ii) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or offsite;
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;
Less than Significant Impact with Mitigation Incorporated As detailed in the proposed project’s HWQTR and in Section 4.10 a) above, the proposed project would incorporate operational LID BMPs as required by the Los Angeles County MS4 Permit.
Issuance of a grading permit for future proposed projects within PA1, would require implementation of MM HYD-1, Hydraulic Study. This mitigation measure would require applicants for grading permits pursuant to the proposed MCTA to prepare a hydraulic study. The hydraulic study would evaluate the ability of existing downstream infrastructure to safely collect and convey any additional runoff created by future projects into the existing storm drainage system in accordance with San Dimas and LA County standards.
The hydraulic study would be required prior to review and approval of grading plans by the Building Official and City Engineer. Also, future projects would be to comply with the MS4 Permit, the Los Angeles County LID Manual, or future MS4 permits that would become effective in the future. Lastly, new projects would comply with applicable local ordinances from the City or local water agency to limit excess irrigation water into the PA1 storm drainage system (Engeo, 2022, pg. 11) The MS4 and the project HWQTR would require the implementation of BMPs and other features which would ensure that runoff is treated prior to discharge into native soils (infiltration), storm drains or other regional stormwater conveyance facilities, as described in the MS4 Permit. Therefore, upon adherence to existing state water quality requirements, including MS4 requirements, the proposed project would minimize or avoid causing a substantial increase in the rate or amount of surface runoff in a manner which would: (1) result in flooding on- or offsite; (2) would not 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 (3) 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. Impacts would be less than significant, and no mitigation is proposed.
MM HYD-1 Hydraulic Study. This mitigation measure would require applicants for grading permits pursuant to the proposed MCTA to prepare a hydraulic study. The hydraulic study would evaluate the ability of existing downstream infrastructure to safely collect and convey any additional runoff created by future projects into the existing storm drainage system in accordance with San Dimas and LA County standards. The hydraulic study must be approved by the City Engineer and would be required prior to review and approval of grading plans by the Building Official and City Engineer.
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iv) Impede or redirect flood flows?
No Impact
The project site is outside of 100-year and 500-year flood zones; the project is within an area designated as Zone D “Areas of Undetermined Flood Hazards”. Zone D includes areas with possible but undetermined flood hazards for which no flood hazard analysis has been conducted. (FEMA, 2022a, b). Implementation of the proposed MCTA would not impede or redirect flood flows, and no impact would occur.
d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation?
No Impact
As described in Section 4.10 iv) above, the proposed project site is above the 100-year and the 500-year flood hazard zones and it is not anticipated that the site would become inundated due to flood.
A tsunami is a sea wave (or series of waves) of local or distant origin that results from large-scale seafloor displacements associated with large earthquakes, major submarine slides, or exploding volcanic islands (California Seismic Safety Commission, 2020). Tsunami Inundation Zones (zones) are not mapped for Los Angeles County (CGS, 2022). A review of the Orange County, California Tsunami Inundation Maps (CGS, 2022) revealed that the tsunami inundation zone nearest to the project site is in the City of Los Alamitos in western Orange County, approximately 40 miles southwest of the project site. Therefore, no tsunami hazard is present onsite and project development would not risk release of pollutants due to tsunami inundation.
A seiche is an oscillating wave caused by wind, tidal forces, earthquakes, landslides, and other phenomena in a closed or partially closed water body such as a river, lake, reservoir, pond, and other large inland water body. A review of aerial imagery (Google Earth, 2022) revealed no water bodies large enough to support a seiche near the proposed project site. Therefore, it is not anticipated that the proposed project would be inundated by a seiche.
The project site is outside of dam inundation areas mapped by the Department of Water Resources (DWR, 2022b). Project development would not risk release of pollutants due to dam inundation.
Implementation of the proposed MCTA would not result in impacts from floods, tsunamis, or seiches, or related water quality hazards. No impact would occur. e) Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan?
Less than Significant Impact
The project site is in the Los Angeles Regional Water Quality Control Board (LARWQCB)’s jurisdictional area. The water quality control plan in effect in the project region is the LARWQCB Basin Plan issued in 2014. The groundwater management plan in effect in the project region is the Five-Year Water Quality and Supply Plan issued by the Main San Gabriel Basin Watermaster (Watermaster). The Basin Plan sets forth water quality objectives for surface waters and groundwater basins in the LARWQCB region; beneficial uses, that is, uses to which water can be put 7145/ San Dimas MCTA 20-0005 Page 4.10-6
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to use for the benefit of people and wildlife; plans, policies, and actions intended to achieve water quality objectives; and describes monitoring and assessment programs used to measure attainment of water quality objectives (LARWQCB, 2014).
The Five-Year Water Quality and Supply Plan describes the Watermaster’s programs for developing and monitoring water supplies; drought management; and water quality cleanup, monitoring, and pollution prevention programs (Watermaster, 2021).
The MS4 Permit discussed in Section 4.10.a was issued pursuant to the Basin Plan. Therefore, implementation of the grading permits, pursuant to the proposed MCTA, in accordance with the MS4 permit would assure that project operation would conform with plans and policies specified in the Basin Plan. Impacts would be less than significant.
Project impacts on groundwater would be less than significant, as substantiated in Section 4.10.b above. Therefore, project development would not conflict or obstruct implementation of the FiveYear Water Quality and Supply Plan. Impacts would be less than significant. 7145/ San Dimas MCTA 20-0005 Page 4.10-7
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4.11 Land Use and Planning
Less than
Potentially
Significant
Impact
Significant
Impact with
Mitigation
Less than
Significant
Impact
No
Impact Would the project:
Incorporated
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
X
X
mitigating an environmental effect?
b) Would the project physically divide an established community? No Impact
The project site is part of a residential neighborhood in the San Jose Hills in the southern part of the City of San Dimas. Most of the site comprises 36 lots for single-family residential development, 29 of which are developed. The project proposes an increase in allowable grading in the rear portions of the lots onsite. The lots are all private properties and are not used for access through the neighborhood or between properties. Therefore, project implementation would not divide an established community and no impact would occur.
c) 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?
No Impact
As shown in Figure 4.11-1, the City’s General Plan land use designation for the project site is Single Family Very Low, which allows a density of 0.2 to 3.0 dwelling units per acre. As shown in Figure
4.11-2, the City’s zoning designation for the project site is Specific Plan 11, which allows for singlefamily residential development (City of San Dimas Municipal Code -City of San Dimas, 2021). The project proposes an increase in allowable grading on existing single-family residential lots (most of them are already developed, seven remaining vacant). The project does not propose a change in land uses or other actions which would conflict with the existing zoning and General Plan land use designations. Project implementation would not conflict with any applicable land use plan, policy, or regulation and no impact would occur.
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Figure 4.11-1
PROJECT SITE CURRENT GENERAL PLAN LAND USE DESIGNATIONS 7145/San Dimas MCTA 20-0005
Initial Study/Mitigated Negative Declaration