Agenda packet — Yorba Linda City Council, January 21, 2025 (part 3 of 8)

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DE C EMBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA
P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24» 3-7 Table 3.B: Regulatory Compliance Measures
Regulatory Compliance Measures (RCMs)
Responsible Party/
Approving Agency
Timing for Regulatory
Compliance Measure

4.5: Cultural Resources
RCM CUL-1 Human Remains. In the event that human remains are encountered on the project site, work within 50 feet of the discovery shall be redirected and the Orange County Coroner notified immediately consistent with the requirements of California Code of Regulations (CCR) Section 15064.5(e). State Health and Safety Code Section 7050.5 states that no further disturbance shall occur until the County Coroner has made a determination of origin and disposition pursuant to Public Resources Code (PRC) Section 5097.98. If the remains are determined to be Native American, the County Coroner shall notify the Native American Heritage Commission (NAHC), which shall determine and notify a Most Likely Descendant (MLD). With the permission of the City of Yorba Linda (City), the MLD may inspect the site of the discovery. The MLD shall complete the inspection within 48 hours of notification by the NAHC. The MLD may recommend scientific removal and nondestructive analysis of human remains and items associated with Native American burials. Consistent with CCR Section 15064.5(d), if the remains are determined to be Native American and an MLD is notified, the City shall consult with the MLD as identified by the NAHC to develop an agreement for treatment and disposition of the remains. Prior to the issuance of grading permits, the City Director of Public Works, or designee, shall verify that all grading plans specify the requirements of CCR Section 15064.5(e), State Health and Safety Code Section 7050.5, and PRC Section 5097.98, as stated above.

Construction
Contractor and
County Coroner/
Director of the City of
Yorba Linda Public
Works Department,
or designee
During construction
activities

4.6: Energy
There are no RCMs related to energy resources that would be applicable to the proposed project.

4.7: Geology and Soils
RCM GEO-1 Imported Soil Standards. Imported soils used for structural backfill shall be comprised of granular, non-expansive soil that conforms to the latest edition of “Greenbook” Standard Specifications for Public Works Construction. “Non-expansive” can be defined as soil having an expansion index (EI) of 20 or less in accordance with American Society for Testing and Materials (ASTM) Standard D4829, last updated January 2021.

City of Yorba Linda
Public Works
Department
Prior to and
throughout the
duration of grading
activities

4.8: Greenhouse Gas Emissions
There are no RCMs related to greenhouse gas emissions that would be applicable to the proposed project.

4.9: Hazards and Hazardous Materials
There are no RCMs related to hazards and hazardous materials that would be applicable to the proposed project.

Page 293 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DE C EMBER 2024
3 P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24» -8 Table 3.B: Regulatory Compliance Measures
Regulatory Compliance Measures (RCMs)
Responsible Party/
Approving Agency
Timing for Regulatory
Compliance Measure

4.10: Hydrology and Water Quality
RCM HYD-1 Construction General Permit. Prior to commencement of construction activities, the City of Yorba Linda (City) Public Works Department shall obtain coverage under the State Water Resources Control Board (SWRCB) National Pollutant Discharge Elimination System (NPDES) General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities (Order No. 2022-0057-DWQ, National Pollutant Discharge Elimination System No.

CAS000002) (Construction General Permit). This shall include submission of Permit Registration Documents (PRDs), including a Notice of Intent (NOI) for coverage under the permit to the SWRCB via the Stormwater Multiple Application and Report Tracking System (SMARTS). The City of Yorba Linda Public Works Department shall demonstrate proof of coverage under the Construction General Permit. Project construction shall not be initiated until a WDID is received from the SWRCB and is provided to the City, or designee. A Stormwater Pollution Prevention Plan (SWPPP) shall be prepared and implemented for the proposed project in compliance with the requirements of the Construction General Permit. The SWPPP shall identify construction Best Management Practices (BMPs) to be implemented to ensure that the potential for soil erosion and sedimentation is minimized and to control the discharge of pollutants in stormwater runoff as a result of construction activities. Upon completion of construction activities and stabilization of the project limits, a Notice of Termination shall be submitted via SMARTS.

Construction
Contractor, City of
Yorba Linda Public
Works Department
Prior to
commencement of
construction activities
RCM HYD-2 City Municipal Code Chapter 16.04. During and post-construction, the Construction Contractor shall comply with Chapter 16.04, Water Quality Control, of the City of Yorba Linda Municipal Code.

Prior to the issuance by the City of a grading permit, building permit and/or safety permit, the property owner shall submit to and obtain the approval of the City Engineer of a Water Quality Management Plan (WQMP).

During and post-construction, the City shall ensure that all applicable BMPs set forth in the WQMP are being properly implemented to ensure that the discharge of pollutants from the site will be reduced to the maximum extent practicable and will not cause or contribute to an exceedance of water quality standards.

Construction
Contractor, City of
Yorba Linda Public
Works Department
During and postconstruction

Page 294 of 1177 ends

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DE C EMBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA
P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24» 3-9 Table 3.B: Regulatory Compliance Measures
Regulatory Compliance Measures (RCMs)
Responsible Party/
Approving Agency
Timing for Regulatory
Compliance Measure
RCM HYD-3 Groundwater Discharge Permit. If groundwater dewatering is required during construction of the proposed project, the City of Yorba Linda Public Works Department shall submit a Notice of Intent (NOI) for coverage under the permit to the Santa Ana RWQCB at least 60 days prior to the start of excavation activities and anticipated discharge of dewatered groundwater to surface waters in order to obtain coverage under the General Waste Discharge Requirements for Discharges to Surface Waters That Pose an Insignificant (De Minimis) Threat to Water Quality (Groundwater Discharge Permit), Order No. R8-2020-0006, NPDES No. CAG998001. The construction contractor shall comply with the requirements of Order No. R8-2020-0006, NPDES No. CAG998001. Groundwater dewatering activities shall comply with all applicable provisions in the Groundwater Discharge Permit, including water sampling, analysis, treatment (if required), and reporting of dewatering-related discharges. Upon completion of groundwater dewatering activities, a Notice of Termination shall be submitted to the Santa Ana RWQCB.

Construction
Contractor, City of
Yorba Linda Public
Works Department
RCM HYD-4 MS4 Permit. Prior to construction, the Construction Contractor shall prepare a WQMP consistent with the requirements of the Model Water Quality Management Plan (WQMP) (County of Orange 2011), Technical Guidance Document for the Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans (WQMPs) (OC Public Works 2013), the City of Yorba Linda Local Implementation Plan (LIP) (2010), and Managing Wet Weather with Green Infrastructure Municipal Handbook Green Streets (EPA 2008), or subsequent guidance manuals. The Final WQMP shall specify the BMPs to be incorporated into the project design to target pollutants of concern in runoff from the project area. The BMPs specified in the Final WQMP shall be incorporated into the final project design, in accordance with the NPDES Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems (MS4s) Draining the Watersheds Within the Orange County Region, Order No. R8-2009-0030, NPDES No. CAS618030 as amended by Order No. R8-2010- 0062 (MS4 Permit). The City shall ensure the implementation of all feasible BMPs. The City shall implement, maintain and operate all such BMPs in a timely and reasonably diligent manner.

Construction
Contractor, City of
Yorba Linda Public
Works Department
Prior to
commencement of
construction activities

4.11: Land Use and Planning
There are no RCMs related to land use and planning that would be applicable to the proposed project.

4.12: Mineral Resources
There are no RCMs related to mineral resources that would be applicable to the proposed project.

4.13: Noise
There are no RCMs related to noise that would be applicable to the proposed project.

4.14: Population and Housing
There are no RCMs related to population and housing that would be applicable to the proposed project.

Page 295 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DE C EMBER 2024
3 P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24» -10 Table 3.B: Regulatory Compliance Measures
Regulatory Compliance Measures (RCMs)
Responsible Party/
Approving Agency
Timing for Regulatory
Compliance Measure

4.15: Public Services
There are no RCMs related to public services that would be applicable to the proposed project.

4.16: Recreation
There are no RCMs related to recreation that would be applicable to the proposed project.

4.17: Transportation
There are no RCMs related to transportation that would be applicable to the proposed project.

4.18: Tribal Cultural Resources
There are no RCMs related to tribal cultural resources that would be applicable to the proposed project.

4.19: Utilities and Service Systems
There are no RCMs related to utilities and service systems that would be applicable to the proposed project.

4.20: Wildfire
There are no RCMs related to wildfire that would be applicable to the proposed project.

Page 296 of 1177 ends

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DECEMBE R 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA
P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24»

APPENDIX A

DRAFT INITIAL STUDY/MITIGATED NEGATIVE DECLARATION

Page 297 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA , C ALIFORNIA

F INAL INITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
DECEMBER 2024
P:\2023\20231457 - BKF Yorba Linda_Imperial Hwy\Final ISMND\12-2024 DRAFT YL Imperial Improvements Project_Final ISMND.docx «12/06/24» This page intentionally left blank

Page 298 of 1177 ends

October 2024
DRAFT

INITIAL STUDY /

MITIGATED NEGATIVE DECLARATION
YORBA LINDA BOULEVARD IMPROVEMENTS PROJECT –

FROM IMPERIAL HIGHWAY TO LAKEVIEW AVENUE

YORBA LINDA, CALIFORNIA

Page 299 of 1177 ends

This page intentionally left blank

Page 300 of 1177 ends

October 2024
DRAFT

INITIAL STUDY /

MITIGAT ED NEGATIVE DECLARATION
YORBA LINDA BOULEVARD IMPROVEMENTS PROJECT –

FROM IMPERIAL HIGHWAY TO LAKEVIEW AVENUE

YORBA LINDA, CALIFORNIA
Submitted to:

City of Yorba Linda
Department of Public Works
4845 Casa Loma Avenue
Yorba Linda, California 92886
Prepared by:

LSA
3210 El Camino Real, Suite 100
Irvine, California 92602
(949) 553-0666
Project No. 20231457

Page 301 of 1177 ends

This page intentionally left blank

Page 302 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

TABLE OF CONTENTS
TABLE OF CONTENTS ............................................................................................................................... i FIGURES AND TABLES ............................................................................................................................ iii LIST OF ABBREVIATIONS AND ACRONYMS............................................................................................ iv

1.0 INTRODUCTION................................................................................................ 1-1

1.1 Contact Person..................................................................................................................1-1

2.0 PROJECT DESCRIPTION ..................................................................................... 2-1

2.1 Existing Conditions............................................................................................................2-1

2.2 Proposed Project...............................................................................................................2-5

3.0 ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED........................................ 3-1

3.1 Determination...................................................................................................................3-1

4.0 EVALUATION OF ENVIRONMENTAL IMPACTS ................................................... 4-1

4.1 Aesthetics..........................................................................................................................4-3

4.2 Agriculture and Forestry Resources..................................................................................4-8

4.3 Air Quality .......................................................................................................................4-11

4.4 Biological Resources........................................................................................................4-20

4.5 Cultural Resources ..........................................................................................................4-25

4.6 Energy..............................................................................................................................4-28

4.7 Geology and Soils............................................................................................................4-31

4.8 Greenhouse Gas Emissions.............................................................................................4-38

4.9 Hazards and Hazardous Materials...................................................................................4-43

4.10 Hydrology and Water Quality .........................................................................................4-48

4.11 Land Use and Planning....................................................................................................4-64

4.12 Mineral Resources...........................................................................................................4-69

4.13 Noise................................................................................................................................4-71

4.14 Population and Housing..................................................................................................4-80

4.15 Public Services.................................................................................................................4-81

4.16 Recreation.......................................................................................................................4-86

4.17 Transportation ................................................................................................................4-88

4.18 Tribal Cultural Resources ................................................................................................4-95

4.19 Utilities and Service Systems.........................................................................................4-100

4.20 Wildfire..........................................................................................................................4-107

4.21 Mandatory Findings of Significance ..............................................................................4-109

5.0 MITIGATION MONITORING AND REPORTING PROGRAM .................................. 5-1

5.1 Mitigation Monitoring Requirements...............................................................................5-1

5.2 Mitigation Monitoring Procedures ...................................................................................5-1

5.3 Regulatory Compliance Measure Monitoring Procedures................................................5-2

6.0 LIST OF PREPARERS .......................................................................................... 6-1

6.1 City of Yorba Linda ............................................................................................................6-1

6.2 BKF Engineers....................................................................................................................6-1

Page 303 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
ii

6.3 LSA Associates, Inc............................................................................................................ 6-1

6.4 Ninyo & Moore ................................................................................................................. 6-2

6.5 W.G. Zimmerman Engineering, Inc................................................................................... 6-2

7.0 REFERENCES ..................................................................................................... 7-1

APPENDICES
A: AIR QUALITY MEMORANDUM / CALEEMOD OUTPUT SHEETS
B: BIOLOGICAL RESOURCES ASSESSMENT
C: CULTURAL RESOURCES STUDY
D: GEOTECHNICAL EVALUATION
E: PALEONTOLOGICAL RESOURCES MEMORANDUM
F: WATER QUALITY MANAGEMENT PLAN
G: NOISE AND VIBRATION IMPACT ANALYSIS MEMORANDUM
H: TRAFFIC STUDIES
I: TRIBAL CONSULTATION RECORD

Page 304 of 1177 ends

iii

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

FIGURES AND TABLES

FIGURES
Figure 2-1: Project Location and Vicinity.............................................................................................2-3 Figure 2-2: Project Improvements.......................................................................................................2-7 Figure 2-3: Property Acquisitions and Easements.............................................................................2-13 TABLES
Table 2.A: Property Acquisitions.......................................................................................................2-12 Table 4.3.A: Attainment Status of Criteria Pollutants in the South Coast Air Basin..........................4-12 Table 4.3.B: SCAQMD Construction and Operation Thresholds of Significance (lbs/day)................4-12 Table 4.3.C: SCAQMD Localized Significance Thresholds..................................................................4-13 Table 4.3.D: Short-Term Regional Construction Emissions...............................................................4-16 Table 4.3.E: Project Localized Construction Emissions .....................................................................4-18 Table 4.8.A: Construction Greenhouse Gas Emissions......................................................................4-39 Table 4.11.A: Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) Policy Consistency Analysis......................................................................................................4-65 Table 4.11.B: General Plan Policy Consistency Analysis....................................................................4-67 Table 4.13.A: Long-Term Ambient Noise Level Measurements........................................................4-73 Table 4.13.B: Existing Traffic Noise Levels.........................................................................................4-74 Table 4.13.C: Typical Construction Equipment Noise Levels ............................................................4-75 Table 4.13.D: Existing (2023) Traffic Noise Levels Without and With Project ..................................4-77 Table 4.13.E: Future (2025) Traffic Noise Levels Without and With Project.....................................4-77 Table 4.13.F: Vibration Source Amplitudes for Construction Equipment.........................................4-79 Table 4.15.A: Regional and State Park Facilities................................................................................4-84 Table 4.17.A: Existing Conditions (2023) Intersection Level of Service ............................................4-90 Table 4.17.B: Future Conditions (2025) Intersection Level of Service ..............................................4-91 Table 4.17.C: Study Intersection Queue Lengths..............................................................................4-91 Table 4.18.A: Assembly Bill 52 Tribal Outreach Recipients...............................................................4-97 Table 5.A: Mitigation Monitoring and Reporting Program .................................................................5-3 Table 5.B: Regulatory Compliance Measures......................................................................................5-6

Page 305 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
iv

LIST OF ABBREVIATIONS AND ACRONYMS
AAQS ambient air quality standards
AB Assembly Bill
ADT average daily traffic
AELUP Airport Environs Land Use Plan
ALUC Airport Land Use Commission
APN Assessor’s Parcel Number
AQ/GHG Memo Air Quality and Greenhouse Gas Emissions Technical Memorandum AQMP Air Quality Management Plan
ASTM American Society for Testing and Materials
Basin South Coast Air Basin
Basin Plan Water Quality Control Plan for the San Diego Basin bgs below ground surface
BMPs Best Management Practices
BRA Biological Resources Assessment
BTU British thermal units
CA/T Central Artery/Tunnel
CAAQS California ambient air quality standards
CAL FIRE California Department of Forestry and Fire Protection CalEEMod California Emissions Estimator Model
CalEPA California Environmental Protection Agency
CalRecycle California Department of Resources Recycling and Recovery Caltrans California Department of Transportation

Page 306 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
CARB California Air Resources Board
CBC California Building Code
CCR California Code of Regulations
CDFW California Department of Fish and Wildlife
CEC California Energy Commission
CEQA California Environmental Quality Act
CH4 methane
CHRIS California Historical Resources Information System CIDH Cast-In-Drilled-Hole
City City of Yorba Linda
CMP Congestion Management Program
CNDDB California Natural Diversity Database
CNEL Community Noise Equivalent Level
CO carbon monoxide
CO2 carbon dioxide
CO2e carbon dioxide equivalent
Coastal Plan Basin Coastal Plain of Orange County Groundwater Basin (also known as Basin 8-1)
CSUF California State University, Fullerton
CWA Clean Water Act
CWMP Construction Waste Management Plan
DAMP Drainage Area Management Plan
dB decibels
dBA A-weighted decibels

Page 307 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
vi
DOC California Department of Conservation
DTSC California Department of Toxic Substances Control
DWR Department of Water Resources
EI expansion index
EMS emergency medical services
EO Executive Order
FEMA Federal Emergency Management Agency
FHSZ fire hazard severity zones
FHWA Federal Highway Administration
FIRM Flood Insurance Rate Map
FRAP Fire and Resources Assessment Program
ft foot/feet
GHGs Greenhouse Gases
GSAs Groundwater Sustainability Agencies
GSPs Groundwater Sustainability Plans
GWh gigawatt-hours
GWP Global Warming Potential
HCP Habitat Conservation Plan
HFCs hydrofluorocarbons
ICU intersection capacity utilization
in/sec inches per second
IRWD Irvine Ranch Water District
IS/MND Initial Study/Mitigated Negative Declaration
Kizh Nation Gabrieleño Band of Mission Indians – Kizh Nation

Page 308 of 1177 ends

vii

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
L10 the noise level exceeded ten percent of the time during a stated period L50 the noise level representing the median noise level L90 the noise level exceeded 90 percent of the time during a stated time period
lbs/day pounds per day
Ldn day-night average noise level
LED light-emitting diode
Leq equivalent continuous sound level
LID Low Impact Development
LIP Local Implementation Plan
LMAD Landscaping Maintenance District
Lmax maximum noise level
Lmin minimum noise level
LOS Level of Service
LRAs Local Responsibility Areas
LSTs localized significance thresholds
LUST Leaking Underground Storage Tank
MAWA Maximum Applied Water Allowance
MBTA Migratory Bird Treaty Act
MLD Most Likely Descendant
MM Mitigation Measure
MRZs Mineral Resource Zones
MS4s Municipal Separate Storm Sewer Systems
MT CO2e metric tons of “CO2 equivalents

Page 309 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
viii
MWELO Model Water Efficient Landscape Ordinance
N/A not applicable
N2O nitrous oxide
NAAQS National Ambient Air Quality Standards
NAHC Native American Heritage Commission
NCCP Natural Community Conservation Plan
NCCP/HCP Natural Community Conservation Plan/Habitat Conservation Plan NF3 nitrogen trifluoride
NHMLAC Natural History Museum of Los Angeles County
NO2 nitrogen dioxide
NOA naturally occurring asbestos
NOI Notice of Intent
Noise Memo Noise and Vibration Impact Analysis Memorandum NOX nitrogen oxides
NPDES National Pollutant Discharge Elimination System
O3 ozone
OC San Orange County Sanitation District
OCFA Orange County Fire Authority
OCSD Orange County Sheriff’s Department
OCTA Orange County Transportation Authority
OCWD Orange County Water District
Paleo Memo Paleontological Resources Memorandum
Pb lead
PFCs perfluorocarbons

Page 310 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
PM10 particulate matter less than 10 microns in diameter PM2.5 particulate matter less than 2.5 microns in diameter PPV peak-particle velocity
PRC Public Resources Code
PRDs Permit Registration Documents
PRMP Parks and Recreation Master Plan
project Yorba Linda Boulevard Improvements Project – from Imperial Highway to Lakeview Avenue
PYLUSD Placentia-Yorba Linda Unified School District
R-A Residential Agricultural
RCM Regulatory Compliance Measure
RTP/SCS Regional Transportation Plan/Sustainable Communities Strategy RWQCB Regional Water Quality Control Board
SB Senate Bill
SCAG Southern California Association of Governments
SCAQMD South Coast Air Quality Management District
SCCIC South Central Information Center
SCE Southern California Edison
SF6 sulfur hexafluoride
SGMA Sustainable Groundwater Management Act
SLF Sacred Lands File
SMARA Surface Mining and Reclamation Act
SMARTS Stormwater Multiple Application and Report Tracking System SO2 sulfur dioxide

Page 311 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
x
SoCalGas Southern California Gas Company
SOX sulfur oxides
SR-57 State Route 57
SR-91 State Route 91
SRA Source Receptor Area
SRAs State Responsibility Areas
SVP Society of Vertebrate Paleontology
SWPPP Storm Water Pollution Prevention Plan
SWRCB State Water Resources Control Board
TCR tribal cultural resources
Technical Advisory Technical Advisory on Evaluating Transportation Impacts in CEQA TMDLs Total Maximum Daily Loads
TPD tons per day
USACE United States Army Corps of Engineers
USC United States Code
USDOT United States Department of Transportation
USEPA United States Environmental Protection Agency
USFWS United States Fish and Wildlife Service
USGS United States Geological Survey
UST Underground Storage Tank
UWMP Urban Water Management Plan
UWMP Act Urban Water Management Plan Act of 1983
V/C volume to capacity
VHFHSZ Very High Fire Hazard Severity Zones

Page 312 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
VMT vehicle miles traveled
VOC volatile organic compounds
WDR Waste Discharge Requirements
WGZE W.G. Zimmerman Engineering, Inc.

WQMP Water Quality Management Plan
YLTC Yorba Linda Town Center
YLWD Yorba Linda Water District

Page 313 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 314 of 1177 ends

1-1

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

1.0 INTRODUCTION
In accordance with the California Environmental Quality Act (CEQA) and the State CEQA Guidelines, this Initial Study/Mitigated Negative Declaration (IS/MND) has been prepared for the proposed Yorba Linda Boulevard Improvements Project – from Imperial Highway to Lakeview Avenue (project) in Yorba Linda, California. Consistent with State CEQA Guidelines Section 15071, this IS/MND includes a description of the proposed project, an evaluation of the potential environmental impacts, and findings from the environmental analysis.

This IS/MND evaluates the potential environmental impacts that may result from development of the project. Consistent with State CEQA Guidelines Section 15050, the City of Yorba Linda (City) is the Lead Agency under CEQA and is responsible for adoption of the IS/MND and approval of the project.

1.1 CONTACT PERSON
Any questions or comments regarding the preparation of this IS/MND, its assumptions, or its conclusions should be referred to:

Rick Yee, PE, Deputy Director
City of Yorba Linda
Department of Public Works
4845 Casa Loma Avenue
Yorba Linda, CA 92886
Tel: (714) 961-7171
Email: [email protected]

Page 315 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 316 of 1177 ends

2-1

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

2.0 PROJECT DESCRIPTION
The Yorba Linda Boulevard Improvements Project – from Imperial Highway to Lakeview Avenue (proposed project) is located along Yorba Linda Boulevard from its intersection with Imperial Highway to its intersection with Lakeview Avenue in the City of Yorba Linda (City), Orange County, California.

The project limits measure approximately 0.28 mile along Yorba Linda Boulevard east of Park Avenue and west of Avocado Avenue.

2.1 EXISTING CONDITIONS

2.1.1 Regional Project Location
The proposed project would consist of improvements to an approximately 0.28-mile segment of Yorba Linda Boulevard between Park Avenue and Avocado Avenue, including the-roadway’s intersections with Imperial Highway and Lakeview Avenue. Please refer to Figure 2-1, Project Location and Vicinity, for a visual depiction of the proposed project’s geographic context.

Yorba Linda Boulevard originates just west of State College Boulevard in the City of Fullerton and runs east to west through the cities of Placentia and Yorba Linda until it transitions into Weir Canyon Road at State Route 91 (SR-91) near the City of Anaheim. According to the City of Yorba Linda’s General Plan Circulation Element, Yorba Linda Boulevard is classified as a Modified Major arterial roadway, which is a six-lane divided roadway, with 84 to 106 feet of curb-to-curb width within 100 feet of rightof-way. Though the City considers 120 feet to be the optimal width, the Modified Major arterial classification signifies that all six lanes are able to be accommodated within a minimum of 100 feet.

Regional access to the project limits is provided by Imperial Highway, which is classified in the City’s General Plan Circulation Element as a six-lane Smart Street north of Yorba Linda Boulevard and a fourlane Smart Street south of Yorba Linda Boulevard. Lakeview Avenue, which intersects with Yorba Linda Boulevard within the project limits, is classified as a four-lane Secondary Arterial north of Yorba Linda Boulevard and a four-lane Primary Arterial south of Yorba Linda Boulevard.

2.1.2 Project Vicinity and Surrounding Land Uses
The portion of Yorba Linda Boulevard where improvements are proposed (project limits) is bounded to the north by Richard Nixon Park, a single-family residential neighborhood, and commercial uses including retail and restaurants. Similarly, the project limits are bounded to the south by commercial uses and an apartment complex. Several unsignalized driveways along Yorba Linda Boulevard provide access to these residential, recreational, and commercial uses.

Park Avenue, which serves as the western project limit, generally runs north-south with an eventual curve in the northwest direction and serves single-family residential uses. Avocado Avenue, which serves as the eastern project limit, runs perpendicular to Yorba Linda Boulevard in the north-south direction and serves several single-family residential neighborhoods.

Page 317 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 318 of 1177 ends

SOURCE: Esri Topographic 2024
J:\20231457\GIS\Pro\Yorba Linda Blvd Project\Yorba Linda Blvd Project.aprx (5/13/2024) FIGURE 2-1
Yorba Linda Boulevard Improvements Project
L O S

A N G E L E S

C O U N T Y

O R A N G E

C O U N T Y
Ã142
Ã73
Ã19
Ã261
Ã1 Ã133
Ã72
Ã90
Ã39
Ã55
Ã22
Ã241
Ã60
Ã71
Ã Ã91
57 §¨¦210
§¨¦605
§¨¦5
§¨¦15
§¨¦405
§¨¦10
Project Vicinity
0 1000 2000
FEET
Project Location
Project Location and Vicinity

Page 319 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 320 of 1177 ends

2-5

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

2.1.3 Existing Roadway
The City of Yorba Linda is proposing roadway improvements at the intersections of Yorba Linda Boulevard and Imperial Highway and Yorba Linda Boulevard and Lakeview Avenue. In the existing condition, Yorba Linda Boulevard travels in the east-west direction. In the easterly direction at the intersection with Imperial Highway, Yorba Linda Boulevard currently consists of one left-turn lane and three through lanes; the westerly direction currently consists of one left-turn lane, three through lanes, and two right-turn lanes onto northbound Imperial Highway. In the easterly direction at the intersection with Lakeview Avenue, Yorba Linda Boulevard currently consists of one left-turn lane and three through lanes; the westerly direction currently consists of one left-turn lane and three through lanes. Imperial Highway travels in the north-south direction. In the northerly direction, Imperial Highway currently consists of one left-turn lane and three through lanes; the southerly direction currently consists of two (dual) left-turn lanes and three through lanes. Lakeview Avenue travels in the north-south direction. In the northerly direction, Lakeview Avenue currently consists of two (dual) left-turn lanes, two through lanes, and one right-turn lane onto eastbound Yorba Linda Boulevard; the southerly direction currently consists of two (dual) left-turn lanes, two through lanes, and a bike lane.

2.2 PROPOSED PROJECT

2.2.1 Yorba Linda Boulevard and Imperial Highway Intersection Figure 2-2, Project Improvements, provides a visual representation of the proposed improvements to the project limits. The project improvements proposed for the intersection of Yorba Linda Boulevard and Imperial Highway include the following:
• Convert the eastbound single left-turn lane on Yorba Linda Boulevard to dual left-turn lanes. • Add an eastbound right-turn lane on Yorba Linda Boulevard. • Convert the westbound single left-turn lane on Yorba Linda Boulevard to dual left-turn lanes.

These lanes would also be extended eastward.
• Modify the northerly and southerly curb lines and curb returns and the median along Yorba Linda Boulevard on the western leg of the intersection to accommodate the two additional turn lanes (one additional left turn lane and one new dedicated right turn lane) described above. • Modify the southerly curb line and curb return and the median along Yorba Linda Boulevard on the eastern leg of the intersection to accommodate one additional turn left lane onto southbound Imperial Highway.
• Modify the traffic signals, including relocations as necessary. • Provide necessary utility relocations due to the road widening and potentially for the foundations for the traffic signal modifications.
• Restripe Yorba Linda Boulevard to reflect updated lane configurations.

Page 321 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 322 of 1177 ends

Valencia
Ave
Main St
Arroyo St
Lakeview Ave
Imperial Hwy
Yorba Linda Blvd
J:\20231457\GIS\Pro\Yorba Linda Blvd Project\Yorba Linda Boulevard Improvements Project.aprx (5/13/2024) FIGURE 2-2
Yorba Linda Boulevard Improvements Project
Project Improvements
Project Boundary
Project Improvements
SOURCE: Nearmap Aerial Imagery (September 8, 2023); BKF (10/2023) 0 75 150
FEET

Page 323 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 324 of 1177 ends

2-9

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
• Construct a retaining wall along eastbound Yorba Linda Boulevard just west of the intersection due to the presence of an underground parking garage immediately south of the roadway. In the existing condition, an embankment with a short retaining wall is in place to separate the difference in grade between the back of the sidewalk and the floor of the underground parking garage. The proposed retaining wall would be located 6.5 feet from the existing face of the parking structure.

2.2.2 Yorba Linda Boulevard and Lakeview Avenue Intersection The project improvements proposed for the intersection of Yorba Linda Boulevard and Imperial Highway include the following:
• Convert the eastbound and westbound single left-turn lanes on Yorba Linda Boulevard to dual left-turn lanes.
• Modify the southerly curb line and curb return and the median along Yorba Linda Boulevard on the eastern and western legs of the intersection to accommodate an additional left-turn lane. • Remove the gap in the median along Yorba Linda Boulevard on the eastern leg of the intersection, which is currently used to enter the Firestone Village shopping center. • Modify the traffic signals, including relocations as necessary. • Provide necessary utility relocations due to the road widening and potentially for the foundations for the traffic signal modifications.
• Restripe Yorba Linda Boulevard to reflect updated lane configurations.

2.2.3 Utility Relocations
Utility relocations would be necessary due to the road widening. Additional utilities may need to be relocated for the proposed traffic signal pole foundation relocations The utilities that may need to be relocated include, but are not limited to, the following:
• The transformer on the north side of Yorba Linda Boulevard west of Imperial Highway in the grassy area south of Mimi’s Café.
• Street lights along Yorba Linda Boulevard.
• Irrigation controllers and irrigation lines along Yorba Linda Boulevard. • The catch basin on the north side of Yorba Linda Boulevard west of Imperial Highway in front of the Mimi’s Café Restaurant.
• The traffic signal poles and their associated pull boxes, cabinets, and lines at the northwest, southwest, and southeast corners of the intersection of Yorba Linda Boulevard and Imperial

Page 325 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
2-10
Highway and at the southwest and southeast corners of the intersection of Yorba Linda Boulevard and Lakeview Avenue.
• The fire hydrant, water valves, and water meters on the south side of Yorba Linda Boulevard west of Imperial Highway in front of the Chili’s Restaurant. • The underground backflow preventer on the south side of the Yorba Linda Boulevard west of Imperial Highway in the grassy area in front of the Chili’s Restaurant. • The junction box on the south side of Yorba Linda Boulevard east of Imperial Highway in front of the El Pollo Loco drive-through.
• The Southern California Edison (SCE) vault on the south side of Yorba Linda Boulevard east of Imperial Highway in front of the Galleria de Yorba sign. • The fire hydrant on the south side of Yorba Linda Boulevard in between Imperial Highway and Lakeview Avenue on the west side of the driveway into the Galleria de Yorba shopping center. • The electrical vault on the south side of Yorba Linda Boulevard west of Lakeview Avenue in front of the T-Mobile.
• The SCE vault on the south side of Yorba Linda Boulevard east of Lakeview Avenue and west of the driveway into the Firestone Village shopping center. • The Yorba Linda Water District (YLWD) water enclosure and valve on the south side of Yorba Linda Boulevard east of the driveway to the Firestone Village shopping center. • The SCE cabinet on the south side of Yorba Linda Boulevard east of the driveway to the Firestone Village shopping center.
• Two SCE transformers on the south side of Yorba Linda Boulevard east of Lakeview Avenue in front of the Yorba Linda Palms Apartments
• The fire hydrant and the water meter on the south side of Yorba Linda Boulevard east of Lakeview Avenue in front of the Yorba Linda Palms Apartments.
• The SCE enclosures on the south side of Yorba Linda Boulevard east of Lakeview Avenue in front of the Yorba Linda Palms Apartments.

2.2.4 Retaining Wall and Bridge
In order to add the right-turn lane on eastbound Yorba Linda Boulevard at the intersection with Imperial Highway, a retaining wall would be installed due to the existence of an underground parking garage along the southerly portion of the roadway, which currently serves commercial uses. In the existing condition, an embankment with a short retaining wall is in place to separate the difference in grade between the back of the sidewalk and the floor of the underground parking garage.

Page 326 of 1177 ends

2-11

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
The proposed retaining wall would be located 6.5 feet from the existing face of the parking structure.

The intent would be not to impact the existing retaining wall located at the bottom of the embankment. Cast-In-Drilled-Hole (CIDH) piles or spread footings may be used. The bridge connecting the driveway to the upper deck of the parking structure would be dismantled and replaced with a new bridge and the existing retaining walls on each side of the bridge would be removed.

2.2.5 Firestone Village Shopping Center Access
The Firestone Village shopping center consists of various commercial storefronts and a surface parking lot, and is located to the south of Yorba Linda Boulevard and the East of Lakeview Avenue. Access to the Firestone Village Shopping center from the project limits is provided via driveways along northbound Lakeview Avenue and eastbound Yorba Linda Boulevard.

Under the proposed project, the Firestone Village shopping center would no longer be accessible from westbound Yorba Linda Boulevard due to the proposed removal in the gap of the median. Under proposed conditions, westbound cars would be unable to U-turn at Lakeview Avenue and therefore would have to either continue on Yorba Linda Boulevard and U-turn at Imperial Highway or turn left onto Lakeview Avenue and U-turn. Traffic counts conducted for the proposed project did not support allowing westbound vehicles to U-turn at Lakeview Avenue and removing the protected right turn from northbound Lakeview Avenue onto eastbound Yorba Linda Boulevard.

2.2.6 Property Acquisition
Partial property acquisitions from seven (7) parcels would be necessary to accommodate the road improvements described above. These acquisitions generally consist of strips of curb or parking lot area and would not result in the displacement of any businesses or housing. Prior to construction of the proposed project, the City would confirm all actions involved with these partial acquisitions with the property owners. Please refer to Table 2.A below for a list of the properties using Assessor’s Parcel Numbers (APNs) that would be affected by property acquisitions associated with the proposed project, as well as a brief description of each acquisition. Refer to Figure 2-3, Property Acquisitions and Easements, on the following page for a visual representation of the property acquisitions discussed in Table 2.A below.

2.2.7 Discretionary Actions, Permits, and Other Approvals In accordance with Sections 15050 and 15367 of the State CEQA Guidelines, the City is the designated Lead Agency for the proposed project and has principal authority and jurisdiction for CEQA actions and project approval. Responsible Agencies are those agencies that have jurisdiction or authority over one or more aspects associated with the development of a proposed project and/or mitigation.

Trustee Agencies are State agencies that have jurisdiction by law over natural resources affected by a proposed project.

The discretionary action to be considered by the City as a part of the proposed project includes the following:
• Adoption of the Mitigated Negative Declaration

Page 327 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
2-12
Table 2.A: Property Acquisitions
APN Type Displacements? Purpose
334-391-07 Partial No Curb reduction to accommodate two additional turn lanes (one additional left-turn lane and one new dedicated right-turn lane) on Yorba Linda Boulevard.
343-281-27 Partial No Curb reduction to accommodate new dedicated eastbound right-turn lane on Yorba Linda Boulevard.
348-161-01 Partial No Shifting existing retaining wall to the south to accommodate new lane configurations.
348-161-12 Partial No Shifting existing retaining wall to the south to accommodate new lane configurations.
348-161-13 Partial No Shifting existing retaining wall to the south to accommodate new lane configurations.
348-162-15 Partial No Curb reduction to accommodate an additional left-turn lane on Yorba Linda Boulevard.
348-162-16 Partial No Curb reduction to accommodate an additional left-turn lane on Yorba Linda Boulevard.

Page 328 of 1177 ends

Page 329 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 330 of 1177 ends

Page 331 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 332 of 1177 ends

3-1

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)

3.0 ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED
The environmental factors checked below potentially would be affected by the project and include at least one impact that is a “Potentially Significant Impact,” as indicated by the checklist on the following pages. Please see the Environmental Checklist for additional information.

Aesthetics Agriculture and Forestry Resources Air Quality Biological Resources Cultural Resources Energy
Geology/Soils Greenhouse Gas Emissions Hazards & Hazardous Materials Hydrology/Water Quality Land Use/Planning Mineral Resources Noise Population/Housing Public Services
Recreation Transportation Tribal Cultural Resources
Utilities/Service Systems Wildfire Mandatory Findings of Significance

3.1 DETERMINATION
On the basis of this initial evaluation:

I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION will be prepared.

I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because revisions in the project have been made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION will be prepared.

I find that the proposed project MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required.

I find that the proposed project MAY have a “Potentially Significant Impact” or “Potentially Significant Unless Mitigated” impact on the environment, but at least one effect (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been addressed by mitigation measures based on the earlier analysis as described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the effects that remain to be addressed.

I find that although the proposed project could have a significant effect on the environment, because all potentially significant effects (a) have been analyzed adequately in an earlier ENVIRONMENTAL IMPACT REPORT or NEGATIVE DECLARATION pursuant to applicable standards, and (b) have been avoided or mitigated pursuant to that earlier ENVIRONMENTAL IMPACT REPORT or NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required.

Rick Yee
Deputy Director of Public Works

Date

Page 333 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Page 334 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-1

4.0 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 will not expose sensitive receptors to pollutants, based on a project-specific screening analysis).

2. All answers must take account of the whole action involved, including off-site as well as on-site, 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 a less than significant level (mitigation measures from earlier analyses may be cross-referenced, as discussed below).

5. Earlier analyses may be used where, pursuant to the tiering, Program EIR, or other CEQA process, an effect has been adequately analyzed in an earlier EIR or Negative Declaration (Section 15063 ©(3)(D)). In this case, a brief discussion should identity the following:
a) Earlier Analysis Used. Identify and state where they are 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 which 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.

Page 335 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-2

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.

Page 336 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-3

4.1 AESTHETICS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Except as provided in Public Resources Code Section 21099, would the project:
(a) Have a substantial adverse effect on a scenic vista? (b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?
(c) In non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from a publicly accessible vantage point.) If the project is in an urbanized area, would the project conflict with
applicable zoning and other regulations governing scenic quality?
(d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? Impact Analysis
a) Would the project have a substantial adverse effect on a scenic vista? No Impact. The City of Yorba Linda General Plan does not specifically identify any scenic vistas within the City. However, the General Plan Recreation Element notes that the City’s canyon and hillside areas contain scenic qualities and contains Policy OR-1.2 to preserve the visual quality of these areas.1 The views throughout the project limits consist of relatively flat roadway segments in an urbanized portion of the City surrounded by development on all sides and is not located within the vicinity of any canyon or hillside areas. Views experienced by vehicles and pedestrians along the roadway are generally limited to adjacent shopping centers and parking areas as well as ornamental landscaping. Any potentially scenic views toward the project limits would be blocked by intervening structures up to two stories tall.

The proposed project would not affect the elevation of Yorba Linda Boulevard beyond its current state and would represent a continuation of existing uses. As there are no scenic resources that could be blocked by the proposed project and the surrounding area is characterized by buildings up to two stories tall, the proposed project would neither alter an existing scenic vista nor block views of any scenic vistas. For these reasons, the development of the proposed project would not have a substantial adverse effect on a scenic vista. Therefore, no impact would occur, and no mitigation is required.
1 City of Yorba Linda. 2016. General Plan Open Space and Recreation Element. October. Website:
https://www.yorbalindaca.gov/DocumentCenter/View/475/2016-Yorba-Linda-General-Plan-PDF?bidId= (accessed March 14, 2024).

Page 337 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-4
(b) Would the project substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a State scenic highway? No Impact. The California Department of Transportation (Caltrans) Scenic Highway Program protects the natural scenic beauty of the State’s highways and corridors through its designated scenic highways throughout the State. Caltrans defines a scenic highway as any freeway, highway, road, or other public right-of-way that traverses an area of exceptional scenic quality. Other considerations given to a scenic highway designation include how much of the natural landscape a traveler may see and the extent to which visual intrusions degrade the scenic corridor.

The limits of the project are not located within the vicinity of a State-designated scenic highway corridor. The nearest highways eligible or officially designated for the State Scenic Highway Program to the project limits are State Route 91 (SR-91), located approximately 2.6 miles southeast of the project limits, and State Route 57 (SR-57), located approximately 4.5 miles northwest of the project limits.
2 Due to distance and intervening land uses, no portion of the project limits or surrounding area are viewable from the officially designated portion of SR-91, or the eligible portion of SR-57. Further, regardless of proximity to a State-designated scenic highway, the proposed project would include landscaped areas containing trees, shrubs, and grasses in order to enhance the visual character of the corridor and would not damage any scenic resources in the long term. The proposed project would result in a similar appearance to the existing setting. The proposed improvements would not result in substantially different views than those currently experienced by pedestrians, bicyclists, and motorists who travel through the project limits or other off-site viewers. As such, the project would not result in substantial adverse impacts related to the damage of scenic resources within a State Scenic Highway. Therefore, no impacts would occur, and no mitigation is required. (c) In non-urbanized areas, would the project 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. According to the United States Census Bureau, the City of Yorba Linda is located within the Los Angeles—Long Beach—Anaheim, CA Urbanized Area.3 As described in State CEQA Guidelines Section 15387 and defined by the United States Census Bureau, an “urbanized area” is a central city or a group of contiguous cities with a population of 50,000 or more people, together with adjacent densely populated areas having a population density of at least 1,000 people per square mile.4 Therefore, the City is an urbanized area, as are the project limits. Further, surrounding land uses in the vicinity of the project limits are representative of urban densities, including residences and commercial storefronts. Because the project limits are located within an urbanized area, the proposed 2 California Department of Transportation (Caltrans). 2018. California State Scenic Highway System Map.

Website: https://www.arcgis.com/apps/webappviewer/index.html?id=465dfd3d807c46cc8e8057116f1aa caa (accessed March 14, 2024). 3 United States Census Bureau. 2012. 2010 Census – Urbanized Area Reference Map: Los Angeles—Long Beach—Anaheim, CA. Website: https://www2.census.gov/geo/maps/dc10map/UAUC_RefMap/ua/ua514 45_los_angeles--long_beach--anaheim_ca/DC10UA51445_000.pdf (accessed March 14, 2024). 4 United States Census Bureau. 2020. Census Urban Area FAQs. Website: https://www2.census.gov/geo/ pdfs/reference/ua/Census_UA_2020FAQs.pdf (accessed March 14, 2024).

Page 338 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-5
project would have an impact under CEQA if it would conflict with applicable zoning or other regulations governing scenic quality.

One regulation governing scenic quality within the City is City Council Policy E-3, or the City’s Tree Removal and Replacement Policy, as trees are considered a scenic resource by the City. According to the Tree Removal and Replacement Policy, street trees and parkway trees removed within the City shall be replaced at a one-to-one ratio, with a 15-gallon size stock.5 Because the proposed project would involve the widening of Yorba Linda Boulevard into currently landscaped curb areas, several trees would be removed during construction of the proposed project. However, pursuant to the City’s Tree Removal and Replacement Policy, the proposed project would replace any removed trees at a minimum one-to-one ratio. Replacement trees and other plants would replicate the previously present species or consist of drought tolerant trees; therefore, the proposed project would be compliant with the City’s Tree Removal and Replacement Policy.

The City’s General Plan Conservation Element6 contains Policy CN-1.1, which pertains to visual resources and would be applicable to the proposed project. Policy CN-1.1 reads, “Ensure that new development along landscaped corridors preserves unique visual features.” Yorba Linda Boulevard is lined with ornamental trees and would therefore be considered a landscaped corridor. Because the proposed project would result in curb and median realignments, several existing landscaped areas would be affected by vegetation removal, including the removal of ornamental trees. However, as discussed above, any vegetation affected by the proposed project would be replaced with new landscaping features, including native and/or drought tolerant trees, shrubs, and grasses. These new and replacement landscaped areas would preserve the visual character and features of the Yorba Linda Boulevard corridor.

The proposed project would not develop any new land uses within the project limits. An amendment to the City’s General Plan would not be necessary under the proposed project since it would continue an existing land use and would not create any inconsistencies among planning documents. Therefore, the proposed project would not conflict with applicable zoning and other regulations governing scenic quality. As such, impacts would be less than significant, and no mitigation is required. (d) 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 impact of nighttime lighting depends upon the type of use affected, the proximity to the affected use, the intensity of specific lighting, and the background or ambient level of the combined nighttime lighting. Nighttime ambient light levels may vary considerably depending on the age, condition, and abundance of point-of-light sources present in a particular view.

The use of exterior lighting for security and aesthetic illumination of architectural features may 5 City of Yorba Linda City Council. 2020. Policy: City Tree Removal and Replacement. June. Website:
https://www.yorbalindaca.gov/DocumentCenter/View/4713/City-Council-Policy-E-3-City-Tree-Removaland-Replacement?bidId= (accessed March 14, 2024). 6 City of Yorba Linda. 2016. General Plan Conservation Element. October. Website: https://www.yorbalinda ca.gov/DocumentCenter/View/475/2016-Yorba-Linda-General-Plan-PDF?bidId= (accessed March 13, 2024).

Page 339 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-6
contribute to ambient nighttime lighting conditions. Spillover light can be problematic in areas where the ambient conditions are very dark, and there are sensitive uses that depend on that darkness.

The spillover of light onto adjacent properties has the potential to interfere with certain activities, including vision, sleep, privacy, and the general enjoyment of the natural nighttime condition. Light sensitive uses include residential, some commercial and institutional uses, and, in some situations, natural areas. Changes in nighttime lighting may become significant if a proposed project substantially increases ambient lighting conditions beyond its property line and project lighting routinely spills over into adjacent light-sensitive land use areas. Nighttime illumination impacts are evaluated in terms of the project’s net change in ambient lighting conditions and proximity to light-sensitive land uses.

Reflective light (glare) is caused by sunlight or artificial light reflecting from finished surfaces (e.g., window glass) or other reflective materials. Glass and other materials can have many different reflectance characteristics. Buildings constructed of highly reflective materials from which the sun reflects at a low angle commonly cause adverse glare. Reflective light is common in urban areas. Glare generally does not result in the illumination of off-site locations but results in a visible source of light viewable from a distance.

As previously discussed, the project limits are surrounded by residential and commercial uses. The nearest light-sensitive land uses are residential uses, located directly north of Yorba Linda Boulevard near the western project limits and south of Yorba Linda Boulevard near the eastern project limits.

Other sources of light on and adjacent to the project limits include exterior lighting from adjacent properties and commercial signage, traffic signals, and vehicle headlights. The proposed project would not introduce any new sources of reflective light associated with reflective building materials because it proposes roadway improvements and no new buildings.

Construction of the proposed project is not anticipated to introduce substantial new light sources to the project limits. The proposed project would comply with Section 15.48.010 of the City’s Municipal Code pertaining to regulations for construction timing, which states that construction work “is prohibited between the hours of eight [8] p.m. and seven [7] a.m., weekdays, including Saturday, or any time on Sunday or a Federal holiday unless said work is of an emergency nature.” As such, construction activities associated with the proposed project would generally be limited to daylight hours, eliminating the need for substantial amounts of artificial light and therefore eliminating the possibility for nighttime illumination impacts that would affect the ambient lighting in the vicinity of the project limits.

Section 18.26.050 of the City’s Municipal Code states that “lighting shall be stationary and shielded in a manner to direct light away from adjacent properties, public streets, and rights-of-way.” The proposed project would be required to comply with this provision of the City’s Municipal Code and ensure that streetlights do not provide a nuisance to neighboring land uses. Further, the proposed project would comply with the applicable lighting policies set forth in the City’s General Plan Conservation Element,7 as follows:
7 City of Yorba Linda. 2016. General Plan Conservation Element. October. Website: https://www.yorbalinda ca.gov/DocumentCenter/View/476/2016-GP-Conservation-Element?bidId= (accessed March 14, 2024).

Page 340 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-7
• Policy CN-6.1: Support efforts that require outdoor lighting fixtures to be shielded and downdirected in order to minimize glare and light trespass. • Policy CN-6.2: Promote removal, replacement, or retrofit of non-shielded or non-down-directed light fixtures that contribute to glare and light pollution.

The proposed project would protect existing streetlights in place wherever possible, and conditions associated with the remaining streetlights would not change. However, the proposed road widening would necessitate the relocation of approximately six streetlights. In compliance with the City’s General Plan lighting policies identified above, the relocated fixtures would be shielded and downdirected. No new sources of light beyond current conditions, such as additional streetlights or traffic signals, are included under the proposed project. As such, the proposed project would have less than significant impacts pertaining to the creation of a new source of substantial light or glare, and no mitigation is required.

Page 341 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-8

4.2 AGRICULTURE AND FORESTRY RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the California Agricultural Land Evaluation and Site Assessment Model (1997) prepared by the California Dept. of Conservation as an optional model to use in assessing impacts on agriculture and farmland. In determining whether impacts to forest resources, including timberland, are significant environmental effects, lead agencies may refer to information compiled by the California Department of Forestry and Fire Protection regarding the state’s inventory of forest land, including the Forest and Range Assessment Project and the Forest legacy Assessment project; and forest carbon measurement methodology provided in Forest Protocols adopted by the California Air Resources Board. Would the project:
(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 nonagricultural use?
(b) Conflict with existing zoning for agricultural use, or a Williamson Act contract?
(c) Conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code [PRC] Section 12220(g)), timberland (as defined by PRC Section 4526), or timberland zoned Timberland Production (as defined by
Government Code Section 51104(g))?
(d) Result in the loss of forest land or conversion of forest land to non-forest use?
(e) Involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland, to nonagricultural use or conversion of forest land to non-forest use?
Impact Analysis
(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 nonagricultural use? No Impact. As discussed in Chapter 2.0, Project Description, the segment of Yorba Linda Boulevard within the project limits is currently developed and surrounded by residential, commercial, and recreational uses. The entire Yorba Linda Boulevard roadway segment within the project limits is classified as “Urban and Built-Up Land” by the State Department of Conservation, which is defined as land that is occupied by structures with a building density of at least one unit to 1.5 acres, or approximately six structures to a 10-acre parcel.8 This classification indicates that Prime Farmland, Unique Farmland, or Farmland of Statewide Importance is not present within or in proximity to the project limits.
8 California Department of Conservation (DOC). 2018. California Important Farmland Finder. Website:
https://maps.conservation.ca.gov/DLRP/CIFF/ (accessed February 21, 2024).

Page 342 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-9
According to the City of Yorba Linda’s General Plan Conservation Element, the City contains minimal agricultural land, limited to two small parcels.
9 The closest parcel, located approximately 0.81 mile
south of the project limits, consists of Unique Farmland. The proposed project would provide mobility and access improvements to an existing roadway within an urbanized portion of the City and would not convert farmland to a nonagricultural use. Therefore, no impacts to agricultural resources would occur, and no mitigation is required.
(b) Would the project conflict with existing zoning for agricultural use, or a Williamson Act contract? No Impact. The proposed project limits include a transportation corridor, Yorba Linda Boulevard, which is surrounded by land zoned for residential, commercial, and planned development uses. 10 The
project limits are not within the vicinity of any parcels zoned for agricultural use, and do not propose any changes to existing City zoning designations. The City’s zoning code does not contain any largescale agricultural production zones and agricultural land uses are limited to the Residential Agricultural (R-A) zone, which is intended for “large rural estates with abundant open space on each lot, or large parcels devoted to commercial or non-commercial agriculture and/or grazing, which may have a residence and other accessory buildings such as barns, equipment sheds, and other similar buildings.”11 The nearest R-A zone to the project limits islocated approximately 0.42 mile to the north.

As discussed above in Response 4.2(a) above, the City contains minimal agricultural land. The project limits and adjacent parcels are considered Urban and Built-Up Land, and are not indicated to be land enrolled in a Williamson Act contract by the State Department of Conservation. Therefore, there would be no conflict with existing zoning for agricultural use or a Williamson Act contract. No impact would occur, and no mitigation is required.
(c) Would the project conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code [PRC] Section 12220(g)), timberland (as defined by PRC Section 4526), or timberland zoned Timberland Production (as defined by Government Code Section 51104(g))? No Impact. The entirety of the project limits are currently used for timberland production, are not zoned as forest land or timberland,12 and do not contain forest land or timberland as defined by Public Resources Code (PRC) Section 1220(g), PRC Section 4526, or Government Code Section 51104(g).

Therefore, no impacts to forest land or timberland would occur, and no mitigation is required. (d) Would the project result in the loss of forest land or conversion of forest land to non-forest use? No Impact. The project limits and surrounding area are currently developed and highly disturbed.

Yorba Linda Boulevard is a transportation corridor surrounded by urban land uses and does not contain forest land. The proposed project involves improvements to an existing roadway and would not convert forest land to a non-forest use. As such, the proposed project would not contribute to 9 City of Yorba Linda. 2016. General Plan Conservation Element. October. Website: https://www.yorbalinda ca.gov/DocumentCenter/View/476/2016-GP-Conservation-Element?bidId= (accessed February 21, 2024). 10 City of Yorba Linda. 2019. Zoning Map. December 12. Website: https://www.yorbalindaca.gov/Document Center/View/466/City-of-Yorba-Linda-Zoning-Map-PDF (accessed February 21, 2024). 11 City of Yorba Linda. Municipal Code Section 18.10.020. Website: https://library.qcode.us/lib/yorba_linda_ ca/pub/municipal_code/item/title_18-chapter_18_10-18_10_020 (accessed February 21, 2024). 12 City of Yorba Linda. 2019. Zoning Map. December 12. Website: https://www.yorbalindaca.gov/Document Center/View/466/City-of-Yorba-Linda-Zoning-Map-PDF (accessed February 21, 2024).

Page 343 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Therefore, no impact would occur, and no mitigation is required. (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 nonagricultural use or conversion of forestland to non-forest use?
No Impact. The areas within the project limits are not currently used for agricultural production and do not contain any forest land. As discussed above in Response 4.2(a), the City contains little undeveloped land, and the project limits and adjacent parcels are considered Urban and Built-Up Land. Thus, the proposed project would not convert farmland to a non-agriculture use. Likewise, because the project limits are already developed and are not located within the vicinity of any existing agricultural land or land zoned for agricultural uses, the proposed project would not contribute to environmental changes that could result in the conversion of farmland to non-agricultural use.

Therefore, no impact would occur, and no mitigation is required.

Page 344 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-11

4.3 AIR QUALITY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Where available, the significance criteria established by the applicable air quality management district or air pollution control district may be relied upon to make the following determinations. Would the project:
(a) Conflict with or obstruct implementation of the applicable air quality plan?
(b) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable federal or state ambient air quality standard?
(c) Expose sensitive receptors to substantial pollutant concentrations?
(d) Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
The analysis presented in the following section is based upon the Air Quality and Greenhouse Gas Emissions Technical Memorandum (AQ/GHG Memo) prepared for the proposed project, which involved emissions modeling using the California Emissions Estimator Model version 2022.1 (CalEEMod) computer program. The AQ/GHG Memo is included within this IS/MND as Appendix A.

A region’s topographic features have a direct correlation with air pollution flow and therefore are used to determine the boundary of air basins. The proposed project is in the City of Yorba Linda, Orange County, and is within the jurisdiction of the South Coast Air Quality Management District (SCAQMD), which regulates air quality in the South Coast Air Basin (Basin). The Basin comprises approximately 10,000 square miles and covers all of Orange County and the urban parts of Los Angeles, Riverside, and San Bernardino Counties. The Basin is on a coastal plain with connecting broad valleys and low hills to the east. Regionally, the Basin is bounded by the Pacific Ocean to the southwest and high mountains to the east, forming the inland perimeter.

The federal Clean Air Act and the California Clean Air Act mandate the control and reduction of specific air pollutants. Under these acts, the United States Environmental Protection Agency (USEPA) and the California Air Resources Board (CARB) have established ambient air quality standards for six criteria air pollutants: carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), lead (Pb), and suspended particulate matter. In addition, the State has set standards for sulfates, hydrogen sulfide, vinyl chloride, and visibility-reducing particles. These standards are designed to protect the health and welfare of the populace with a reasonable margin of safety. Two criteria pollutants, O3 and NO2, are considered regional pollutants because they (or their precursors) affect air quality on a regional scale. Pollutants such as CO, SO2, and Pb are considered local pollutants that tend to accumulate in the air locally.

Air quality monitoring stations are located throughout the nation and are maintained by the local air districts and State air quality regulating agencies. Data collected at permanent monitoring stations are used by the USEPA to identify regions as “attainment” or “nonattainment” depending on whether the regions meet the requirements stated in the applicable National Ambient Air Quality Standards (NAAQS). Nonattainment areas are imposed with additional restrictions as required by the USEPA.

In addition, different classifications of attainment (e.g., marginal, moderate, serious, severe, and

Page 345 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-12
extreme) are used to classify each air basin in the State on a pollutant-by-pollutant basis. The classifications are used as a foundation to create air quality management strategies to improve air quality and to comply with the NAAQS. As shown in Table 4.3.A, the Basin is designated as nonattainment by federal standards for O3 and particulate matter less than 2.5 microns in diameter (PM2.5) and nonattainment by State standards for O3, particulate matter less than 10 microns in diameter (PM10), and PM2.5. On February 7, 2024, the USEPA strengthened the NAAQS for PM2.5 by revising the primary (health-based) annual standard from 12.0 micrograms per cubic meter (µg/m3 )
to 9.0 µg/m3
; however, a new attainment designation has not been issued.

Table 4.3.A: Attainment Status of Criteria Pollutants in the South Coast Air Basin Pollutant State Federal
O3 1-hour Nonattainment N/A
O3 8-hour Nonattainment Extreme Nonattainment
PM10 Nonattainment Attainment/Maintenance
PM2.5 Nonattainment Nonattainment
CO Attainment Attainment/Maintenance
NO2 Attainment Unclassified/Attainment (1-hour)
Attainment/Maintenance (Annual)
SO2 Attainment Unclassified/Attainment
Lead Nonattainment1 Unclassified/Attainment1
All Others Attainment/Unclassified Attainment/Unclassified Source 1: NAAQS and CAAQS Attainment Status for South Coast Air Basin (SCAQMD 2016). Website: www.aqmd.gov/docs/defaultsource/clean-air-plans/air-quality-management-plans/naaqs-caaqs-feb2016.pdf (accessed August 2024).

Source 2: Nonattainment Areas for Criteria Pollutants (Green Book) (EPA 2019). Website: www.epa.gov/green-book (accessed August 2024). 1 Only the Los Angeles County portion of the South Coast Air Basin is in nonattainment for lead.

CAAQS = California Ambient Air Quality Standards
CO = carbon monoxide
EPA = United States Environmental Protection Agency
N/A = not applicable
NAAQS = National Ambient Air Quality Standards
NO2 = nitrogen dioxide
O3 = ozone
PM10 = particulate matter less than 10 microns in diameter PM2.5 = particulate matter less than 2.5 microns in diameter SCAQMD = South Coast Air Quality Management District
SO2 = sulfur dioxide
The SCAQMD considers any project in the Basin with construction- or operation-related emissions that exceed any of the following emission thresholds to have potentially significant impacts. The emission thresholds were established based on the attainment status of the Basin with regards to air quality standards for specific criteria pollutants. Because the concentration standards were set at a level that protects public health with an adequate margin of safety, these emission thresholds are regarded as conservative and would overstate an individual project’s contribution to health risks.

Table 4.3.B lists the California Environmental Quality Act (CEQA) significance thresholds for construction and operational emissions established for the Basin.

Table 4.3.B: SCAQMD Construction and Operation Thresholds of Significance (lbs/day) Emission Source Pollutant Emissions Threshold (lbs/day) VOC NOX CO SO2 PM10 PM2.5
Construction Thresholds 75 100 550 150 150 55
Operation Thresholds 55 55 550 150 150 55
Source: South Coast Air Quality Management District (1993).

Page 346 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-13
In addition, the SCAQMD published its Final Localized Significance Threshold Methodology in June 2003 (updated July 2008), recommending that all air quality analyses include an assessment of air quality impacts to nearby sensitive receptors.13 This guidance was used to analyze potential localized air quality impacts associated with construction of the proposed project. Localized significance thresholds (LSTs) are developed based on the size or total area of the emissions source, the ambient air quality in the source receptor area, and the distance to the project. Sensitive receptors include residences, schools, hospitals, and similar uses that are sensitive to adverse air quality. The closest sensitive receptors to the project limits include the Yorba Linda Palms Apartments adjacent to the south side of Yorba Linda Boulevard toward the east end of the project limits.

LSTs are based on the ambient concentrations of that pollutant within the project Source Receptor Area (SRA) and the distance to the nearest sensitive receptor. For the proposed project, the appropriate SRA for the LST is the North Orange County area (SRA 16). SCAQMD provides LST screening tables for 25-, 50-, 100-, 200-, and 500-meter source-receptor distances. As identified above, the closest sensitive receptors to the project limits include the Yorba Linda Palms Apartments adjacent to the south side of Yorba Linda Boulevard toward the east end of the project limits. The minimum distance that SCAQMD recommends using for LST analyses is 25 meters. Based on the anticipated construction equipment and based on anticipated grading and ground-disturbing activities, it is assumed that the maximum daily disturbed acreage for the proposed project would be

4.3 acres.14 As such, the LSTs for a 4.3-acre site at a distance of 25 meters were derived by interpolation. Table 4.3.C lists the localized emissions thresholds that would apply during project construction.

Table 4.3.C: SCAQMD Localized Significance Thresholds
Emissions Source Pollutant Emissions Threshold (lbs/day) NOx CO PM10 PM2.5
Construction (4.3-acre, 25-meter distance) 204 1,183 10 6 Operational (4.3-acre, 25-meter distance) 204 1,183 3 2 Source: Final Localized Significance Threshold Methodology (SCAQMD, July 2008).

CO = carbon monoxide
lbs/day = pounds per day
NOx = nitrogen oxides
PM10 = particulate matter less than 10 microns in size
PM2.5 = particulate matter less than 2.5 microns in size SCAQMD = South Coast Air Quality Management District
Impact Analysis
(a) Would the project conflict with or obstruct implementation of the applicable air quality plan? Less Than Significant Impact. An Air Quality Management Plan (AQMP) describes air pollution control strategies to be undertaken by a city or county in a region classified as a nonattainment area to meet the requirements of the federal Clean Air Act. As previously stated, the Basin is in nonattainment for by federal standards for O3 and particulate matter less than 2.5 microns in diameter (PM2.5) and nonattainment by State standards for O3, particulate matter less than 10 microns in diameter (PM10), and PM2.5. The main purpose of an AQMP is to bring an area into compliance with the requirements 13 South Coast Air Quality Management District (SCAQMD). 2008. Final Localized Significance Threshold Methodology. July. Website: http://www.aqmd.gov/docs/default-source/ceqa/handbook/localizedsignificance-thresholds/final-lst-methodology-document.pdf (accessed January 15, 2024). 14 Ibid.

Page 347 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-14
of federal and State ambient air quality standards (AAQS). Every 3 years, the South Coast Air Quality Management District (SCAQMD) prepares a new AQMP, updating the previous plan and 20-year horizon.15 The Final 2022 Air Quality Management Plan is the currently adopted AQMP.

A consistency determination plays an essential role in local agency project review by linking local planning and unique individual projects to the air quality plans. A consistency determination fulfills the CEQA goal of fully informing local agency decision-makers of the environmental costs of the project under consideration at a stage early enough to ensure that air quality concerns are addressed.

Only new or amended General Plan elements, Specific Plans, and significantly unique projects need to undergo a consistency review given that the air quality plan strategy is based on projections from local General Plans.

The City of Yorba Linda’s General Plan is consistent with the Southern California Association of Governments (SCAG) Regional Comprehensive Plan Guidelines and the SCAQMD AQMP. Pursuant to the methodology provided in the SCAQMD CEQA Air Quality Handbook, 16 consistency with the Basin
AQMP is affirmed when a project (1) would not increase the frequency or severity of an air quality standards violation or cause a new violation, and (2) is consistent with the growth assumptions in the AQMP.

The proposed project would result in short-term construction and long-term operational pollutant emissions that are all less than the CEQA significance emissions thresholds established by the SCAQMD, as demonstrated below in Response 4.3(b); therefore, the proposed project would not result in an increase in the frequency or severity of an air quality standards violation or cause a new air quality standards violation. Further, the CEQA Air Quality Handbook indicates that consistency with AQMP growth assumptions must be analyzed for new or amended General Plan elements, Specific Plans, and significant projects. Significant projects include airports, electrical generating facilities, petroleum and gas refineries, designation of oil drilling districts, water ports, solid waste disposal sites, and offshore drilling facilities.

The proposed project would improve the intersections of Yorba Linda Boulevard and Imperial Highway and Yorba Linda Boulevard and Lakeview Avenue within an approximately 0.28-mile segment; therefore, the proposed project is not defined as significant. In addition, the proposed project would not require a change to the General Plan land use designation or the current zoning. Based on the consistency analysis presented above, the proposed project would be consistent with the regional AQMP. Impacts related to conflict with or obstruct implementation of the applicable air quality plan would be less than significant, and no mitigation is required. 15 South Coast Air Quality Management District (SCAQMD). 2022. Final 2022 Air Quality Management Plan.

December 2. 16 South Coast Air Quality Management District (SCAQMD). 1993. CEQA Air Quality Handbook. Website:
http://www.aqmd.gov/home/rules-compliance/ceqa/air-quality-analysis-handbook/ceqa-air-qualityhandbook-(1993) (accessed April 2024).

Page 348 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-15
(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. As identified above, the Basin is currently designated as nonattainment for the federal and State standards for O3 and PM2.5. The Basin’s nonattainment status is attributed to the region’s development history. Past, present, and future development projects contribute to the region’s adverse air quality impacts on a cumulative basis. By its very nature, air pollution is largely a cumulative impact. No single project is sufficient in size to, by itself, to result in nonattainment of AAQS. Instead, a project’s individual emissions contribute to existing cumulatively significant adverse air quality impacts. If a project’s contribution to the cumulative impact is considerable, then the project’s impact on air quality would be considered significant.

In developing thresholds of significance for air pollutants, the SCAQMD considered the emission levels for which a project’s individual emissions would be cumulatively considerable. If a project exceeds the identified SCAQMD significance thresholds identified above in Table 4.3.B, its emissions would be cumulatively considerable, resulting in significant adverse air quality impacts to the region’s existing air quality conditions. Therefore, additional analysis to assess cumulative impacts is not necessary.

The following analysis assesses the potential project-level air quality impacts associated with construction and operation of the proposed project.

Construction. During construction, short-term degradation of air quality may occur due to the release of particulate matter emissions (i.e., fugitive dust) generated by site preparation and grading activities. Emissions from construction equipment are also anticipated and would include CO, nitrogen oxides (NOX), volatile organic compounds (VOCs), directly emitted PM2.5 or PM10, and toxic air contaminants such as diesel exhaust particulate matter.

Project construction activities would include demolition of existing facilities, relocation of utilities, construction of roadway widening, construction of retaining wall and parking structure modification, construction of hardscaping and street improvements, construction of landscape and irrigation, completion of roadway paving and roadway striping. Sources of fugitive dust would include disturbed soils at the construction site. Unless properly controlled, vehicles leaving the site would deposit dirt and mud on local streets, which could be an additional source of airborne dust after it dries. Fugitive dust emissions would vary from day to day, depending on the nature and magnitude of construction activity and local weather conditions. Fugitive dust emissions would depend on soil moisture, silt content of soil, wind speed, and amount of operating equipment. Larger dust particles would settle near the source, whereas fine particles would be dispersed over greater distances from the construction site.

The SCAQMD has established Rule 403: Fugitive Dust, which would require the Construction Contractor to implement measures that would reduce the amount of particulate matter generated during the construction period. The Rule 403 measures that were incorporated in this analysis include:
• Watering active sites at least twice daily (locations where earth disturbance is to occur shall be thoroughly watered prior to earthmoving).

Page 349 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-16
• Covering all trucks hauling dirt, sand, soil, or other loose materials, or maintain at least 2 feet (0.6 meter) of freeboard (vertical space between the top of the load and the top of the trailer) in accordance with the requirements of California Vehicle Code Section 23114. • Reducing traffic speeds on all unpaved roads to 15 miles per hour or less.

In addition to dust-related PM10 emissions, heavy trucks and construction equipment powered by gasoline and diesel engines would generate CO, sulfur oxides (SOX), NOX, VOCs, and some soot particulate (PM2.5 and PM10) in exhaust emissions. If construction activities were to increase traffic congestion in the area, CO and other emissions from traffic would increase slightly while those vehicles idle in traffic. These emissions would be temporary in nature and limited to the immediate area surrounding the construction site.

The California Emissions Estimator Model version 2022.1 (CalEEMod) computer program was used to calculate emissions from on-site construction equipment and emissions from worker and vehicle trips to and from the construction areas within the proposed project limits. This analysis assumes that construction would begin in January 2026 and would occur for approximately 160 working days, ending in August 2026. The proposed project would include the export of 375 cubic yards of soil during the grubbing and land clearing phase and 2,757 cubic yards of soil during the grading and excavation phase, which was included in CalEEMod. The proposed project would also include approximately 161,627 square feet of road and pavement demolition, which was also included in CalEEMod. This analysis assumed compliance with SCAQMD Rule 403 measures. All other construction details are not yet known; therefore, default assumptions (e.g., construction equipment, construction hauling and vendor truck trips, and construction trip lengths and fleet activities) from CalEEMod were used.

Construction emissions were estimated for the proposed project using CalEEMod and are summarized in Table 4.3.D below.

Table 4.3.D: Short-Term Regional Construction Emissions Construction Phase Maximum Daily Regional Pollutant Emissions (lbs/day) VOC NOX CO SOX Total PM10 Total PM2.5
Maximum Daily Emissions 3.6 30.5 38.7 0.1 9.1 1.9
SCAQMD Threshold 75 100 550 150 150 55
Significant? No No No No No No
Source: Compiled by LSA (August 2024).

CO = carbon monoxide
lbs/day = pounds per day
NOX = nitrogen oxides
PM2.5 = particulate matter less than 2.5 microns in size PM10 = particulate matter less than 10 microns in size
SCAQMD = South Coast Air Quality Management District
SOX = sulfur oxides
VOC = volatile organic compounds
As shown in Table 4.3.D, the proposed project would not exceed the significance criteria for daily VOC, NOX, CO, SOX, PM10, or PM2.5 emissions. Therefore, construction of the proposed project would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is in nonattainment under an applicable federal or State Ambient Air Quality Standards (AAQS).

Operation. Long-term air pollutant emission impacts are those associated with mobile sources (e.g., vehicle trips), energy sources (e.g., electricity), and area sources (e.g., landscape maintenance equipment use) related to the proposed project. The proposed project would improve the

Page 350 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-17
intersections of Yorba Linda Boulevard and Imperial Highway and Yorba Linda Boulevard and Lakeview Avenue within an approximately 0.28-mile segment of Yorba Linda Boulevard. Improvements would include modifications to the eastbound and westbound lanes on Yorba Linda Boulevard, the proposed lane additions, modifications to the northerly and southerly curb lines, restriping, and modifications to existing medians, sidewalks, and utilities, as well as current and proposed locations of relevant streetscape features. As discussed in the Traffic Impact Analysis17 prepared for the proposed project, upon completion of construction activities, operation of the proposed project would not result in a significant traffic impact at the study intersections, and the Level of Service (LOS) traffic designation would remain the same as with the existing conditions. In addition, the proposed three additional turn lanes would not add through capacity. Therefore, no additional trips are anticipated due to implementation of the proposed project. As such, the proposed project would not result in an increase in the generation of vehicle trips or vehicle miles traveled (VMT) that would increase air pollutant emissions.

The proposed project would also modify the existing traffic signals to account for the proposed turn lanes; however, the proposed project would not result in a substantial source of energy or area source emissions. In addition, streetlights would be retrofitted with light-emitting diode (LED) bulbs upon their re-installation along the new median, which would have lower energy usage than the bulbs currently being used within the project limits. Furthermore, utility relocations would not result in a substantial source of energy and water source emissions. After relocation, the proposed project would operate similarly to existing conditions. Therefore, operation of the proposed project would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is in nonattainment under an applicable federal or State AAQS. (c) Would the project expose sensitive receptors to substantial pollutant concentrations? Less Than Significant Impact. Sensitive receptors are defined as people who have an increased sensitivity to air pollution or environmental contaminants. Sensitive receptor locations include schools, parks and playgrounds, daycare centers, nursing homes, hospitals, and residential dwelling units. The closest sensitive receptors to the project limits include multifamily residential uses in the Yorba Linda Palms Apartments located adjacent to the south side of Yorba Linda Boulevard toward the east end of the project limits. Table 4.3.E shows the results of the LST analysis during project construction for a 4.3-acre site at a distance of 25 meters.

As detailed in Table 4.3.E, the proposed project would not result in an exceedance of a SCAQMD LST during project construction or operation. During construction, construction contractors would be required to implement measures to reduce or eliminate emissions by implementing SCAQMD Rule 403 dust control measures. In addition, the maximum daily emissions associated with project construction emissions are identified in Table 4.3.E and indicate the project would not exceed the significance criteria for VOC, NO, CO, SOX, PM10, or PM2.5 emissions. Therefore, the emissions associated with construction of the proposed project would not be expected to exceed the most stringent applicable federal or State ambient air quality standards. It should be noted that the ambient air quality standards are developed and represent levels at which the most susceptible persons (children and the elderly) are protected. In other words, the ambient air quality standards are purposefully set low to protect children, the elderly, and those with existing respiratory problems. 17 BKF Engineers, Inc. 2024. Yorba Linda Widening Traffic Impact Study. January 2024.

Page 351 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-18
Table 4.3.E: Project Localized Construction Emissions
Source Pollutant Emissions (lbs/day)
NOX CO PM10 PM2.5
On-Site Emissions 29.9 36.5 6.7 1.4
Localized Significance Threshold 204 1,183 10 6
Significant? No No No No
Source: Compiled by LSA (August 2024).

Note: Source Receptor Area 16, based on a 4.3-acre construction disturbance daily area, at a distance of 82 feet (25 meters) from the project boundary.

CO = carbon monoxide
lbs/day = pounds per day
NOX = nitrogen oxides
PM2.5 = particulate matter less than 2.5 microns in size PM10 = particulate matter less than 10 microns in size
Therefore, given the temporary nature of short-term construction impacts, and the absence of any exceeded threshold of significance related to construction impacts, construction of the proposed project would not exceed SCAQMD thresholds and would not expose nearby sensitive receptors to substantial pollutant concentrations. No significant health risk would occur from project construction emissions. Furthermore, as discussed above in Response 4.3(b), the proposed project’s operational activities would not be considered significant. Therefore, the project would not expose sensitive receptors to substantial pollutant concentrations during project construction or operation.

Asbestos. The project limits are within Orange County, which is among the counties found to have serpentine and ultramafic rock, or naturally occurring asbestos in their soils.18 However, according to the California Geological Survey, no such rock has been identified in the vicinity of the project limits.

As described above, the proposed project would undergo median/curb modifications, resurfacing, and utility relocations which would require asphalt demolition. As such, asphalt demolition may expose asbestos used in building materials; however, the proposed project would be required to comply with SCAQMD Rule 1403: Asbestos demolition and removal, which would help reduce asbestos exposure. Therefore, with compliance of SCAQMD Rule 1403, the potential risk related to asbestos during project construction is small and would be considered to be less than significant.

Based on the analysis presented above, impacts related to exposure of sensitive receptors to substantial pollutant concentrations would be less than significant, and mitigation is not required. (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. Heavy-duty equipment within the project limits during construction would emit odors, primarily from equipment exhaust. However, the construction activity would cease after individual construction is completed. No other sources of objectionable odors have been identified for the proposed project.

SCAQMD Rule 402 regarding nuisances states: “A person shall not discharge from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which endanger 18 California Department of Conservation (DOC). California Geological Survey. n.d. Asbestos. Website:
https://www.conservation.ca.gov/cgs/minerals/mineral-hazards (accessed January 15, 2024).

Page 352 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-19
the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property.” The proposed uses are not anticipated to emit any objectionable odors. Therefore, the proposed project would not result in other emissions (such as those leading to odors) adversely affecting a substantial number of people.

Page 353 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-20

4.4 BIOLOGICAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a
candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife (CDFW) or United States Fish and Wildlife Service (USFWS)?
(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 CDFW or USFWS?
(c) Have a substantial adverse effect on State or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means?
(d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with
established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?
(e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?
(f) Conflict with the provisions of an adopted Habitat
Conservation Plan (HCP), Natural Community Conservation Plan (NCCP), or other approved local, regional, or State habitat conservation plan?
The analysis presented in the following section is based upon the Biological Resources Assessment (BRA) prepared for the proposed project in March 2024. This assessment was prepared by a qualified biologist using a methodology consisting of a literature review, record search, and reconnaissancelevel pedestrian field survey. The Biological Resources Assessment is included within this IS/MND as Appendix B.

Impact Analysis
(a) Would the project have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife (CDFW) or U.S. Fish and Wildlife Service (USFWS)?
Less Than Significant Impact. The proposed project limits consist of an existing roadway surrounded by residential and commercial development. However, there are landscaped areas within the project limits that contain ornamental non-native plant species. As stated above, a literature review was conducted in order to determine which special-status biological resources have the potential to occur on or within the general vicinity of the project limits. Specifically, a database search was conducted for the Yorba Linda, California United States Geological Survey (USGS) quadrangle. In addition, a reconnaissance-level pedestrian survey was conducted by a qualified biologist on January 29, 2024,

Page 354 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-21
in order to document existing conditions and observe the presence of special-status biological resources within the project limits.

Common wildlife species observed within the project limits and the vicinity during the January 29, 2024, field survey include:
• Western fence lizard (Sceloporus occidentalis),
• American crow (Corvus brachyrhynchos),
• Red-tailed hawk (Buteo jamaicensis),
• Anna’s hummingbird (Calypte anna),
• Song sparrow (Melospiza melodia), and
• House finch (Haemorhous mexicanus).

These species are commonly found within developed areas throughout Southern California and would not be considered special-status species.

One federally listed Threatened species; the coastal California gnatcatcher (Polioptila californica californica), was identified as potentially present within the vicinity of the project limits. However, it was determined that the existing environment within the project limits and the vicinity would be unsuitable for the coastal California gnatcatcher.

One non-listed special-status species, the American bumble bee (Bombus pensylvanicus), has a low probability of occurrence within the project limits. The project limits overlap with a California Natural Diversity Database (CNDDB) record for American bumble bee, but the record dates back to 1953, and only one adult was collected. Further, this species was not observed within the project limits during the January 29, 2024, reconnaissance survey. Because the species was not observed and due to the developed nature of the project limits and surrounding land, impacts to this species are anticipated to be less than significant. No other non-listed special-status species identified in the literature review are expected to occur within the project limits or the vicinity due to historic and ongoing humanrelated disturbances leading to the lack of suitable habitat for these species.

Based on the analysis presented above, no federally or State Threatened or Endangered species are anticipated to be impacted by the proposed project due to the lack of suitable habitat and the developed conditions within the project limits. However, the project limits contain several ornamental trees that could potentially provide suitable nesting habitat for a variety of native and migratory protected bird species. Nesting bird species are protected by California Fish and Game Code Sections 3503, 3503.5, and 3800, and by the Migratory Bird Treaty Act (MBTA) (16 United States Code [USC] 703–711). To ensure compliance with these regulations, the proposed project shall implement Regulatory Compliance Measures (RCMs) BIO-1 through BIO-3, which set forth nest avoidance measures.

Because no special-status plant or animal species were observed within the project limits during the December 8, 2023, site visit, and with incorporation of RCMs BIO-1 through BIO-3, potential impacts to special-status species would be less than significant.

Page 355 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-22
Regulatory Compliance Measures
RCM BIO-1 Construction Activity. If possible, vegetation removal should be avoided during the nesting bird season (February 1–August 31). If the nesting bird season is unavoidable, prior to construction activities, including vegetation removal, a pre-construction nesting bird survey shall be conducted by a qualified biologist no more than 3 days (72 hours) prior to any construction activities and vegetation removal. Should nesting birds be found, an exclusionary buffer shall be established by the qualified biologist. The buffer shall be clearly marked in the field by construction personnel under guidance of the qualified biologist. No construction activities shall be allowed within this zone until the qualified biologist determines that the young have fledged, or the nest is no longer active.

RCM BIO-2 Tree Trimming and Removal. To the greatest extent feasible, tree trimming/ removal activities shall be performed outside of the nesting season for birds (February 1–August 31). If trimming or removal of trees during the nesting bird season cannot be avoided, a qualified biologist shall monitor tree trimming and removal activities.

RCM BIO-3 Night Work Lighting. If possible, night work should be avoided during the nesting bird season (February 1–August 31). If night work (i.e., between dusk and dawn) is anticipated within 100 feet of an active bird nest and/or nest exclusionary buffer, night lighting shall be used only in areas of active work and focused on the direct area(s) of work and away from nesting locations to the greatest extent practicable. The qualified biologist may adjust the exclusionary buffer size to decrease the possibility of disturbance by night work, if warranted. This measure would minimize disturbance and prevent nest failure. If birds are showing signs of distress, such as flushing from their nests, work activities shall be modified to prevent the nest from being abandoned.
(b) Would the project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the CDFW or USFWS?
No Impact. According to the BRA, based upon a review of the United States Fish and Wildlife Service (USFWS) Wetlands Mapper online edition, the project limits in their current condition do not contain any riparian habitat or indicators thereof. Therefore, the proposed project would not 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 (CDFW) or USFWS. There would be no impact, and no mitigation is required.

Page 356 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-23
(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?
No Impact. There are three key agencies that regulate activities within State and federally protected wetlands in California. The United States Army Corps of Engineers (USACE) Regulatory Branch regulates discharge of dredge or fill materials into “waters of the United States” pursuant to Section 404 of the Clean Water Act (CWA) and Section 10 of the Rivers and Harbors Act. The CDFW regulates alterations to streambed and bank under California Fish and Game Code Sections 1600 et seq., and the Santa Ana Regional Water Quality Control Board (RWQCB) regulates discharges into surface waters pursuant to Section 401 of the CWA and the California Porter-Cologne Water Quality Control Act.

As stated in the BRA, no potential jurisdictional waters of the United States regulated by the USACE or RWQCB, or CDFW jurisdictional lakes, rivers, or streams are present within the project limits. Thus, there would be no project-related effects to jurisdictional waters. Further, based upon a review of the USFWS National Wetlands Inventory Mapper online edition, the project limits do not contain any wetlands or indicators thereof. Therefore, implementation of the proposed project would not have a substantial adverse effect on State or federally protected wetlands through direct removal, filling, hydrological interruption, or other means. No impact would occur, and no mitigation is required. (d) Would the project interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?
Less Than Significant Impact. Habitat linkages provide connections between larger habitat areas that are separated by development. Wildlife corridors are similar to linkages but provide specific opportunities for animals to disperse or migrate between areas. A corridor can be defined as a linear landscape feature of sufficient width to allow animal movement between two comparatively undisturbed habitat fragments. Adequate cover is essential for a corridor to function as a wildlife movement area. It is possible for a habitat corridor to be adequate for one species yet still inadequate for others. Wildlife corridors are features that allow for the dispersal, seasonal migration, breeding, and foraging of a variety of wildlife species. Additionally, open space can provide a buffer against both human disturbance and natural fluctuations in resources.

As previously stated, the project limits include a fully developed roadway and its adjacent areas are fully developed with residential and commercial uses. Wildlife species that occur in the project vicinity are therefore already adapted to the urban-wildland interface. The noise, vibration, light, dust, or human disturbance within construction areas would only temporarily deter wildlife from using areas in the immediate vicinity of construction activities. These indirect effects could temporarily alter migration behaviors, territories, or foraging habitats in select areas. However, these effects would be temporary in nature, and it is likely that wildlife already living in the area would re-establish their normal functions once all temporary construction effects have been removed. As the project limits are surrounded by existing urban development, the proposed project’s activities would not place any permanent barriers within any known wildlife movement corridors or interfere with habitat connectivity.

Page 357 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-24
Further, as discussed above in Response 4.4(a), potential impacts to migratory birds would be less than significant with the proposed project’s incorporation of the avoidance measures set forth in RCMs BIO-1 through BIO-3. Impacts of the proposed project related to interference with wildlife movement would be less than significant, and no mitigation is required. (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. As previously stated, the proposed project would necessitate the removal and replacement of trees within the project limits. Chapter 16.08 of the City of Yorba Linda’s Municipal Code requires that no trees located within public right-of-way or individual vacant lots shall be cut down without a permit issued by the Community Development Director. Pursuant to this provision, the proposed project would not move forward with tree removal activities until a permit from the Community Development Director has been received.

Further, City Council Policy E-3, City Tree Removal and Replacement,19 contains requirements for the planting of new trees. According to Policy E-3, the determination of replanting locations and ratios should be based on the physical space available, number of healthy trees remaining in the immediate area, and Community Design Guidelines. The planting of replacement ornamental trees under the proposed project would adhere to the guidelines set forth in Policy E-3.

Because the proposed project would comply with applicable resource protection policies, including those pertaining to trees, impacts would be less than significant, and no mitigation is required. (f) Would the project conflict with the provisions of an adopted Habitat Conservation Plan (HCP), Natural Community Conservation Plan (NCCP), or other approved local, regional, or State habitat conservation plan?
No Impact. Natural Community Conservation Plans (NCCPs) may be implemented that identify measures necessary to conserve and manage natural biological diversity within the planning area, while allowing compatible and appropriate economic development, growth, and other human uses.

Orange County’s Natural Community Conservation Plan and Habitat Conservation Plan (NCCP/HCP) was approved in 1996 under the State of California’s NCCP program. The NCCP/HCP is intended to ensure the long-term survival of special-status coastal sage scrub-dependent plant and wildlife species, and certain other identified species and habitats while allowing for reasonable economic growth in accordance with State-sanctioned NCCP/HCP program guidelines.

Although the City of Yorba Linda has signed an enrollment agreement with the County of Orange (Central/Coastal) NCCP/HCP, the project limits not located within the planning boundaries of the NCCP/HCP, and the natural resources that are conserved/addressed by the NCCP/HCP are absent from the already developed site; therefore, no further analysis is required. Therefore, impacts within the NCCP Reserve would not occur under the proposed project. 19 City of Yorba Linda City Council. 2020. Policy: City Tree Removal and Replacement. June. Website:
https://www.yorbalindaca.gov/DocumentCenter/View/4713/City-Council-Policy-E-3-City-Tree-Removaland-Replacement?bidId= (accessed March 22, 2024).

Page 358 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-25

4.5 CULTURAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Cause a substantial adverse change in the significance of a historical resource pursuant to Section 15064.5?
(b) Cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5?
(c) Disturb any human remains, including those interred outside of formal cemeteries?
Impact Analysis
This section is based on the information presented in the Cultural Resources Study prepared for the proposed project on March 18, 2024. The Cultural Resources Study includes the results of a records search through the South Central Coastal Information Center (SCCIC) of the California Historical Resources Information System (CHRIS) at California State University, Fullerton (CSUF) and additional research. The Cultural Resources Study is included as Appendix C to this IS/MND. (a) Would the project cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5?
Less Than Significant Impact. A review of online historic period aerial photographs and maps is presented in the Cultural Resources Study. A map from the mid-1890s, the earliest available, shows little development within the region. On a map from 1902, several structures are visible within the vicinity of the project limits, and additional development was visible by the mid-1930s. By 1946, an aerial photograph shows the present-day alignment of the Yorba Linda Boulevard roadway along with adjacent suburban development and orchards, while Imperial Highway was shown as being built and was complete by 1963. Aerial photographs from 1985 and 1992 show road improvements and widening to Yorba Linda Boulevard and Imperial Highway, respectively. As time passed, more suburban development occurred within the vicinity.

In order to identify any potentially present historic resources within the project limits, a records search was conducted at the SCCIC of the CHRIS located at CSUF. The SCCIC is the official repository of cultural resources records for Orange County. The records search, conducted on June 7, 2023, included a review of all recorded historic-period and prehistoric cultural resources within a 0.25-mile radius of the project limits, as well as a review of known cultural resources surveys and excavation reports.

The record search showed that eight previous cultural resource studies have been conducted within

0.25-mile of the project limits, two of which contained an overlap with the project limit boundaries.

While none of the reports documented the presence of cultural resources within the project limits, four historic-period built environment resources were identified within 0.25 mile of the project limits.

All four of the historic-period built environment resources date from to early 20th century, consisting of three residences and one commercial building. Two of the residences (P-20-120210 and P-30-160211) are listed on the National Register of Historic Places and the California Register of

Page 359 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-26
Historic Resources, while the other two were evaluated and found not to be significant. P-30-160210 is a single-family residence built in 1912, which served as the birthplace of former president Richard M. Nixon in 1913. Therefore, this structure is listed for its association with a historical figure.

P-30-160211 is a commercial railroad depot constructed by the Southern Pacific Electric Railway in 1911, listed for its association with early-period transportation and rail commerce.

Because these two listed historic resources are found outside of the project limits, the proposed project would not adversely affect them in any way. Further, based on the records search and previous cultural studies, there are no historic resources present within the project limits or in close proximity to the project limits. As such, impacts to historic resources would be less than significant, and no mitigation is required.
(b) Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5?
Less Than Significant Impact. The soils underlying the proposed project have been previously disturbed by development of the existing Yorba Linda Boulevard roadway and surrounding land uses.

As stated above, in order to identify any potentially present archaeological resources within the project limits, a records search was conducted at the SCCIC on January 10, 2024.

The records search showed that no prehistoric resources have been recorded within the project limits or within an 0.25-mile radius of the project limits. Further, the Cultural Resources Study determined that the fully developed character of the proposed project has led to completely disturbed sediment underlying the project limits, and virtually no potential exists for the project to result in the discovery of archaeological resources in preserved conditions. Therefore, the proposed project would have less than significant impacts relating to archaeological resources, and no mitigation is required. (c) Would the project disturb any humans remains, including those interred outside of formal cemeteries?
Less Than Significant Impact. The area within the project limits is not known to be located near or adjacent to any formal cemeteries, and there are no known human remains interred within the project limits. Additionally, as is indicated previously, due to the developed nature of the project limits, the likelihood of encountering buried cultural resources within the project limits is very low.

However, buried and undiscovered archaeological remains, including human remains, may be present below the ground surface in portions of the project limits. Disturbing human remains could violate the State’s Health and Safety Code, as well as destroy the resource. In the unlikely event that human remains are encountered during project grading, the construction contractor, the City of Yorba Linda, and the County are required to adhere to California Code of Regulations (CCR) Section 15064.5(e), Public Resources Code (PRC) Section 5097, and Section 7050.5 of the State’s Health and Safety Code.

To ensure proper treatment of burials in the event of an unanticipated discovery of a burial, human bone, or suspected human bone, the law requires that all excavation or grading in the vicinity of the find halt immediately, the area of the find be protected, and the contractor immediately notify the County Coroner of the find. If the remains are determined to be Native American, the County Coroner will notify the Native American Heritage Commission (NAHC), which will determine and notify a Most Likely Descendant (MLD) to determine the proper actions to be taken. Compliance with these provisions, as specified in Regulatory Compliance Measure (RCM) CUL-1, would ensure that any potential impacts to unknown buried human remains would be less than significant by ensuring

Page 360 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-27
appropriate examination, treatment, and protection of human remains as required by State law. No mitigation is required.

Regulatory Compliance Measure
RCM CUL-1 Human Remains. In the event that human remains are encountered on the project site, work within 50 feet of the discovery shall be redirected and the Orange County Coroner notified immediately consistent with the requirements of California Code of Regulations (CCR) Section 15064.5(e).

State Health and Safety Code Section 7050.5 states that no further disturbance shall occur until the County Coroner has made a determination of origin and disposition pursuant to Public Resources Code (PRC) Section 5097.98. If the remains are determined to be Native American, the County Coroner shall notify the Native American Heritage Commission (NAHC), which shall determine and notify a Most Likely Descendant (MLD). With the permission of the City of Yorba Linda (City), the MLD may inspect the site of the discovery. The MLD shall complete the inspection within 48 hours of notification by the NAHC. The MLD may recommend scientific removal and nondestructive analysis of human remains and items associated with Native American burials. Consistent with CCR Section 15064.5(d), if the remains are determined to be Native American and an MLD is notified, the City shall consult with the MLD as identified by the NAHC to develop an agreement for treatment and disposition of the remains. Prior to the issuance of grading permits, the City Director of Public Works, or designee, shall verify that all grading plans specify the requirements of CCR Section 15064.5(e), State Health and Safety Code Section 7050.5, and PRC Section 5097.98, as stated above.

Page 361 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-28

4.6 ENERGY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources during project construction or operation? (b) Conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
The City of Yorba Linda and the project limits are located within the service territory of Southern California Edison (SCE). SCE provides electricity to more than 15 million people in a 50,000-squaremile area of Central, Coastal, and Southern California.20 According to the California Energy Commission (CEC), total electricity consumption in the SCE service area in 2022 was 85,870 gigawatthours (GWh) (31,604 GWh for the residential sector and 54,266 GWh for the non-residential sector).

Total electricity consumption in Orange County in 2022 was 20,243.7 GWh (20,243,721,856 kilowatthours [kWh]).21 Natural gas for the City of Yorba Linda is provided by Southern California Gas Company (SoCalGas).

SoCalGas provides natural gas services to around 21.1 million consumers across 500 communities.22 According to the California Energy Commission (CEC), total electricity consumption in the SCE service area in 2022, the most recent year available, was 85,870 gigawatt-hours (GWh). Total electricity consumption in Orange County in 2022 was 20,243.7 GWh (20,243,721,856 kilowatt hours [kWh]).23 Gasoline is the most used transportation fuel in California, with 97 percent of all gasoline being consumed by light-duty cars, pickup trucks, and sport utility vehicles. According to the most recent data available, total gasoline consumption in California was 316,425 thousand barrels or 1,597.6 trillion British thermal units (BTU) in 2022.
24 Of the total gasoline consumption,
299,304 thousand barrels or 1,511.2 trillion BTU were consumed for transportation.25 Based on fuel consumption obtained from EMFAC2021, 157.1 million gallons of diesel and 1.2 billion gallons of gasoline were estimated to be consumed from vehicle trips in Orange County in 2024. 20 Southern California Edison (SCE). 2020. About Us. Website: https://www.sce.com/about-us/who-we-are (accessed July 2024). 21 CEC. 2020a. Electricity Consumption by County and Entity. Website: http://www.ecdms.energy.ca.gov/ elecbycounty.aspx and http://www.ecdms.energy.ca.gov/elecbyutil.aspx (accessed July 2024). 22 Southern California Gas (SoCalGas). n.d. Company Profile. Website: https://www.socalgas.com/aboutus/company-profile (accessed August 2024). 23 CEC. 2020b. California Energy Consumption Database. Website: http://www.ecdms.energy.ca.gov/ (accessed August 2024). 24 A British thermal unit is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. 25 U.S. Energy Information Administration. 2021. California State Profile and Energy Estimates. Table F3:

Motor gasoline consumption, price, and expenditure estimates, 2021. Website: eia.gov/state/seds/ data.php?incfile=/state/seds/sep_fuel/html/fuel_mg.html&sid=CA (accessed August 2024).

Page 362 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-29
Impact Analysis
(a) 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. The proposed project consists of roadway improvements and therefore would not substantially increase the demand for electricity and gasoline when compared to existing site conditions. The discussion and analysis provided below is based on the data included in the CalEEMod output, which is included as Appendix A to this IS/MND.

Construction-Period Energy Use. Construction of the proposed project is anticipated to commence in January 2026 and would occur for approximately 160 working days, ending in August 2026.

Construction activities would include grubbing and land clearing, grading and excavation, drainage, utilities, and sub-grade, and paving activities.

Construction and demolition activities would require energy for the manufacture and transportation of construction materials, preparation of the site for grading and development activities, and development of the proposed project. All or most of this energy would be derived from nonrenewable resources. Petroleum fuels (e.g., diesel and gasoline) would be the primary sources of energy for these activities. Construction of the proposed project would not involve the consumption of natural gas because it is assumed that none of the construction-related equipment would be powered by natural gas.

Construction activities are not anticipated to result in an inefficient use of energy because gasoline and diesel fuel would be supplied by construction contractors who would conserve the use of their supplies to minimize their costs on the proposed project. Energy usage within the project limits during construction would be temporary in nature and would be relatively small in comparison to the State’s available energy sources. Therefore, construction energy impacts would be less than significant.

Operational Energy Use. Operational energy use is typically associated with natural gas use, electricity consumption, and fuel used for vehicle trips associated with the project.

The proposed project would improve operations along Yorba Linda Boulevard as it intersects with Imperial Highway and Lakeview Avenue in order to address the existing and future congestion at these intersections. Proposed improvements include lane conversions, additional lanes, curb modifications, median modifications, traffic signal modifications, utility relocations, restriping, and retaining wall construction. As discussed in Section 4.17, Transportation, upon completion of construction activities, operation of the proposed project would not change existing traffic volumes and no additional trips are anticipated due to implementation of the proposed project; as such, the proposed project is not expected to generate a substantial increase in fuel used for vehicle trips. In addition, existing streetlights along the Yorba Linda Boulevard median would be removed and retrofitted with lightemitting diode (LED) bulbs upon their re-installation along the new median. As such, the project would also not result in a substantial source of energy. Therefore, implementation of the proposed project would not result in additional energy consumption. Therefore, the proposed project would not result in the wasteful, inefficient, or unnecessary consumption of energy resources. Impacts would be less than significant, and no mitigation measures would be necessary.

Page 363 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-30
(b) Would the project conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
Less Than Significant Impact. As indicated above, energy usage within the project limits during construction would be temporary in nature. In addition, once operational, the proposed project would not result in additional energy consumption. As such, the proposed project would not conflict with California’s energy conservation plans as described in the CEC’s 2023 Integrated Energy Policy Report.

Thus, as shown above, the proposed project would avoid or reduce the inefficient, wasteful, and unnecessary consumption of energy and would not result in any irreversible or irretrievable commitments of energy. Therefore, the proposed project would not result in the wasteful, inefficient, or unnecessary consumption of energy resources during project construction or operation. Impacts would be less than significant, and no mitigation measures would be necessary.

Page 364 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-31

4.7 GEOLOGY AND SOILS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:
i. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning
Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42.
ii. Strong seismic ground shaking?
iii. Seismic-related ground failure, including liquefaction? iv. Landslides?
(b) Result in substantial soil erosion or the loss of topsoil? (c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and
potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse?
(d) Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial
direct or indirect risks to life or property?
(e) Have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water?
(f) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?
The analysis presented in the following section is based upon the Geotechnical Evaluation and the Paleontological Resources Memorandum (Paleo Memo) prepared for the proposed project, which are included within this IS/MND as Appendices D and E, respectively.

Impact Analysis
(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. According to the Geotechnical Evaluation, the project limits are located within the central block, one of four blocks within the Los Angeles Basin, in the Peninsular Ranges Geomorphic Province of California. The central block can be generally characterized by uplifted hills and low-lying plains.

Page 365 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-32
Based on a review of seismic hazard maps, geologic literature, and geologic maps presented in the Geotechnical Evaluation, the project limits are not located within a State of California Earthquake Fault (Alquist Priolo) Zone, and no active faults are known to cross within the project limits.

Because there are no known active or potentially active faults or fault traces shown on current geologic maps as crossing or being in close proximity to the project limits, the risk of ground rupture within the project limits is very limited. In addition, the proposed project includes roadway improvements and would not include the construction of any new structuresthat could accommodate human occupancy. Therefore, potential for the exposure of people or structures to potential substantial adverse effects related to fault rupture as provided in the Alquist-Priolo Earthquake Fault Zoning Act is less than significant. No mitigation is required. ii. Strong seismic ground shaking?
Less Than Significant Impact. Ground shaking due to seismic events (earthquakes) would typically be considered the greatest source of potential damage to structures. Seismic shaking is characterized by the physical movement of the land surface during and subsequent to an earthquake. Seismic shaking has the potential to cause destruction and damage to buildings and property, including damage resulting from damaged or destroyed gas or electrical utility lines; blockage of surface seepage and groundwater flow; changes in groundwater flow; dislocation of street alignments; displacement of drainage channels and drains; and possible loss of life. In addition, ground shaking can induce several kinds of secondary seismic effects, including liquefaction, differential settlement, and landslides, all of which are described below.

The intensity of seismic shaking during an earthquake depends largely on geologic formation conditions of the materials comprising the upper several hundred feet of the earth’s surface. The greatest amplitudes and longest durations of ground shaking occur on thick, water-saturated, unconsolidated alluvial sediments. Ground shaking can also cause ground failure or deformation due to lurching and liquefaction.

As previously discussed, the project limits are not located within a currently designated Alquist-Priolo Earthquake Fault Zone. Nevertheless, the proposed project could still be subject to seismic ground shaking from faults outside of the project limits. According to the Geotechnical Evaluation, the project limits are located within the general vicinity of active faults capable of producing a maximum moment magnitude of 6.0 or more, which could cause the area within the project limits to experience strong seismic ground shaking. However, the proposed project’s compliance with State and City of Yorba Linda seismic requirements would minimize the risk of loss, injury, or death resulting from strong ground shaking originating from faults outside the project limits. For example, the proposed project would be required to comply with the California Building Code (CBC), which sets forth specifications for concrete and other components of the proposed project.

Further, the proposed project would improve travel conditions along an existing roadway and does not propose any new inhabitable structures that would place humans at risks associated with seismic ground shaking. Based on the nature of the proposed project, and with adherence to seismic engineering and design criteria, seismic ground shaking hazards at the proposed project would be less than significant, and no mitigation is required.

Page 366 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-33
iii. Seismic-related ground failure, including liquefaction? Less Than Significant Impact. Liquefaction is caused by sudden temporary increases in pore water pressure due to seismic densification or other displacement of submerged granular soils. Layers of loose sand and sandy silt may, therefore, be subject to liquefaction if these materials are or were to become submerged and are also exposed to strong seismic ground shaking. Seismic ground shaking of relatively loose granular soils that are saturated or submerged can cause the soils to liquefy and temporarily behave as a dense fluid. This loss of support can produce local ground failure such as settlement or lateral spreading that may damage overlying improvements. Liquefaction commonly occurs when three conditions are present simultaneously: (1) high groundwater; (2) relatively loose, cohesion-lacking (sandy) soil; and (3) earthquake-generated seismic waves.

According to the Geotechnical Evaluation prepared for the proposed project, the area within the project limits is not located within an area mapped by the California Geological Survey as subject to seismically induced liquefaction hazards. This determination is supported by Exhibit PS-2, Liquefaction Zones, of the City of Yorba Linda’s General Plan Public Health and Safety Element,26 which does not identify the area within the project limits as being prone to liquefaction.

Further, the Geotechnical Evaluation discusses exploratory borings being conducted for the proposed project that reached a total depth of approximately 41.5 feet below ground surface (bgs) and did not encounter any groundwater supplies. Based on regional maps, historic high depth to groundwater has been greater than 30 feet bgs. According to groundwater monitoring well data from the State of California Department of Water Resources (DWR) Geotracker website,27 groundwater was measured at a depth of approximately 65 feet bgs in 2023. Though groundwater levels can fluctuate, this information generally suggests that the project limits do not contain groundwater near the ground surface, and therefore lacks this precursor to liquefaction risk.

In addition, the soils underlying the project limits were determined to consist of relatively dense granular soils and hard fine-grained soils, which do not fit the characteristics of soils prone to liquefaction. Therefore, in addition to not being identified as subject to liquefaction risk in applicable geologic documentation, the project limits lack the conditions that indicate liquefaction risk. Based on these factors, in addition to the fact that the proposed project includes roadway improvements marking the continuation of an existing use and would not include the construction or rehabilitation of structures for human occupancy, the proposed project would have less than significant impacts related to liquefaction. No mitigation is required.
iv. Landslides?
Less Than Significant Impact. Landslides and mudslides include the movement of soils, rocks, and other man-made or natural materials downslope, which can be caused by an earthquake or heavy rainfall.
26 City of Yorba Linda. 2016. General Plan Public Health and Safety Element. October. Website: https://www. yorbalindaca.gov/DocumentCenter/View/473/2016-GP-Public-Health-and-Safety-Element?bidId= (accessed March 12, 2024). 27 State Water Resources Control Board (SWRCB). GeoTracker Database. Website: https://geo tracker. waterboards.ca.gov/ (accessed April 5, 2024).

Page 367 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-34
Figure PS-3, Landslide Zones, of the City’s General Plan Public Health and Safety Element28 highlights the portions of the City at risk of landslides due to geological conditions. Figure PS-3 does not identify the project limits as an area susceptible to landslides. No other relevant geologic hazard maps discussed within the Geotechnical Evaluation identify potential landslide hazards within the project limits.

In addition, the project limits generally consist of level terrain. The project limits contain one sloped area just south of Yorba Linda Boulevard descending toward a parking structure; however, a majority of this slope would be replaced by a proposed retaining wall approximately 6.5 feet from the existing face of the parking structure, which would prevent any downslope movement of soils or other materials. Further, observations of the slope conducted as part of the Geotechnical Evaluation determined that no evidence of instability exists under current conditions.

The proposed project would not introduce any new topographical features or elements that would increase the risk of landslide within the project limits or the vicinity. Further, the proposed project includes improvements of an existing roadway and would not include the construction or rehabilitation of structures for human occupancy. Based on this information and the analysis presented above, potential for the exposure of people or structures to possible substantial adverse effects related to landslides would be less than significant, and no mitigation is required. (b) Would the project result in substantial soil erosion or the loss of topsoil? Less Than Significant Impact. The primary concern in regard to soil erosion or loss of topsoil would be during the construction phase of the proposed project. Grading and earthwork activities associated with the improvements to Yorba Linda Boulevard would require excavation and grading activities and could temporarily expose soils to potential short-term erosion by wind and water. However, since the project limits are relatively flat, potential soil erosion can be controlled via implementation of standard construction erosion control practices such as the use of water to prevent fugitive dust.

Because the surface areas within the project limits would not be prone to erosion with implementation of erosion control practices, the proposed project would not result in substantial soil erosion or the loss of topsoil. Furthermore, the exposure of soils during construction would be shortterm and subject to requirements established by the National Discharge Elimination Systems (NPDES), which are discussed further in Section 4.10, Hydrology and Water Quality, of this IS/MND.

Upon completion, the proposed project would result in an increase in impervious area of approximately 0.13-acre and a net increase in stormwater runoff; however, stormwater runoff generated by the proposed project would continue to drain to the eight curb inlets serving the project limits as described further in Section 4.10, Hydrology and Water Quality, of this IS/MND. The proposed project’s implementation would notsubstantially increase the volume of runoff from the project limits because the proposed project would result in a nominal increase in impervious surface area. In addition, the proposed project’s design includes landscaped pervious areas intended to capture stormwater runoff. Incorporation of Regulatory Compliance Measures (RCM) HYD-1 through HYD-4, discussed further in Section 4.10, Hydrology and Water Quality, of this IS/MND, would minimize the 28 City of Yorba Linda. 2016. General Plan Public Health and Safety Element. October. Website: https://www. yorbalindaca.gov/DocumentCenter/View/473/2016-GP-Public-Health-and-Safety-Element?bidId= (accessed March 12, 2024).

Page 368 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-35
volume of runoff within the project limits that could potentially contribute to erosion. Therefore, direct and indirect impacts related to erosion and loss of topsoil would be less than significant, and no mitigation would be required.
(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. The project limits consist of existing paved roadwaysthat are not known to be unstable. As previously stated, substantial liquefaction- or landslide-related risks do not exist within the project limits based on site characteristics and a review of existing hazard maps presented in the Geotechnical Evaluation.

Lateral spreading often occurs on very gentle slopes or flat terrain. The dominant mode of movement is lateral extension accompanied by shear or tensile fracture. This failure is caused by liquefaction and is usually triggered by rapid ground motion, such as that experienced during an earthquake. Because the area within the project limits is not subject to any substantial liquefaction risks, the likelihood of lateral spreading within the project limits is also considered low and does not pose any significant risks.

Subsidence refers to broad‐scale changes in the elevation of land. Common causes of land subsidence are overpumping water, oil, and gas from underground reservoirs; dissolution of limestone aquifers (sinkholes); collapse of underground mines; drainage of organic soils; and initial wetting of dry soils (hydro compaction). Overpumping and excessive groundwater withdrawal, or other precursors to subsidence, are not known to have occurred within the project limits and the project limits do not include any oil, gas, or water pumps. Further, the Geotechnical Evaluation states that the depth to groundwater and density of soils within the project limits suggest a lack of subsidence risk. As such, the proposed project’s potential impacts related to unstable soils or geologic units would be less than significant, and no mitigation is required.
(d) Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? Less Than Significant Impact. Expansive soils are characterized by their ability to undergo substantial volume changes (shrink or swell) due to variations in moisture content as a result of precipitation, landscape irrigation, utility leakage, roof drainage, perched groundwater, drought, or other factors.

Expansive soils contain types of clay minerals that occupy considerably more volume when they are wet or hydrated than when they are dry or dehydrated. Volume changes associated with changes in the moisture content of near-surface expansive soils can cause uplift or heave of the ground when they become wet or, less commonly, cause settlement when they dry out.

As previously discussed, the project limits consist of existing roadways including medians, curbs, and landscaped areas, and the majority of the area is paved. The soils within the project limits, which currently support the existing roadway uses, are compacted and disturbed. According to the Geotechnical Evaluation prepared for the proposed project, existing soils underlying the project limits should be suitable for use as general fill and trench backfill, though imported soils would likely be needed for fill beneath footings or retaining wall backfill. In compliance with existing standards for structural fill, any soils imported into the project limits would be non-expansive, and would be

Page 369 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-36
conditioned prior to placement in order to ensure optimal moisture conditions. Based on this compliance, the proposed project’s impacts related to expansive soils would be less than significant, and no mitigation is required.

Regulatory Compliance Measure
RCM GEO-1 Imported Soil Standards. Imported soils used for structural backfill shall be comprised of granular, non-expansive soil that conforms to the latest edition of “Greenbook” Standard Specifications for Public Works Construction. “Non-expansive” can be defined as soil having an expansion index (EI) of 20 or less in accordance with American Society for Testing and Materials (ASTM) Standard D4829, last updated January 2021.
(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 is an improvement to the existing roadway and does not include the construction of, or connections to, a septic or alternative wastewater disposal system. Therefore, the proposed project would not result in impacts related to the soil’s capability to adequately support the use of septic tanks or alternative wastewater disposal systems, and no impacts would occur. (f) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? Less Than Significant with Mitigation Incorporated. During preparation of the Paleontological Resources Memorandum (Paleo Memo) prepared for the proposed project (refer to Appendix E of this IS/MND), a review of geologic maps of the project limits and relevant geological and paleontological literature was conducted in order to determine which geologic units are present within the project limits and whether fossils have been recovered within the project limits or from similar geologic units elsewhere in the region. In addition, a fossil locality search was conducted through the Natural History Museum of Los Angeles County (NHMLAC) to determine the status and extent of previously recorded paleontological resources within and surrounding the project limits. According to the Paleo Memo, the fossil locality search did not identify any known fossil localities or other paleontological resources within the boundaries of the project limits. As such, no known paleontological resources exist within the project limits. However, the search noted a number of fossil localities in the region from Pleistocene-age sediments similar to those found within the project limits, as described below.

The project limits contain Artificial Fill, which has no paleontological sensitivity; Young Alluvial Fan Deposits, which have low paleontological sensitivity above a depth of 10 feet and a high sensitivity below that mark; and Very Old Alluvial Fan Deposits, which have high paleontological sensitivity.

Excavation activities associated with the proposed project are expected to reach a depth of 32 feet within sediments of both the Young Alluvial Fan Deposits and Very Old Alluvial Fan Deposits.

Development of the proposed project is thus expected to extend into paleontologically sensitive sediments and has the potential to impact scientifically significant paleontological resources.

To ensure that potential impacts to undiscovered paleontological resources remain less than significant, preparation of a Paleontological Resources Impacts Mitigation Program, paleontological

Page 370 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-37
monitoring of construction activities, appropriate treatment of newly discovered resources, and preparation of a final paleontological monitoring report would be required, as outlined in the Paleo Memo and combined under Mitigation Measure (MM) GEO-1
Mitigation Measures
Compliance with the following MM GEO-1 would ensure that potential adverse impacts related to inadvertent paleontological discoveries would be less than significant.

MM GEO-1 A paleontologist who meets the qualifications established by the Society of Vertebrate Paleontology (SVP) shall be retained to develop a Paleontological Resources Impact Mitigation Program (PRIMP) for this project. The PRIMP shall be consistent with the standards of the SVP and include the methods that will be used to protect paleontological resources that may exist within the project limits, as well as procedures for monitoring, fossil preparation and identification, curation into a repository, and preparation of a report at the conclusion of grading.

Excavation and grading activities in deposits with high paleontological sensitivity (i.e., Young Alluvial Fan Deposits below a depth of 10 feet and Very Old Alluvial Fan Deposits) shall be monitored by a qualified paleontological monitor following a PRIMP.

No monitoring is required for excavations in deposits with no paleontological sensitivity (i.e., Artificial Fill). If paleontological resources are encountered during the course of ground disturbance, the paleontological monitor shall have the authority to temporarily redirect construction away from the area of the find. In the event that paleontological resources are encountered when a paleontological monitor is not present, work in the immediate area of the find shall be redirected, and the paleontologist or paleontological monitor shall be contacted to assess the find for scientific significance. If determined to be scientifically significant, the fossil shall be collected from the field.

Collected resources shall be prepared to the point of identification, identified to the lowest taxonomic level possible, cataloged, and curated into the permanent collections of a museum repository. At the conclusion of the monitoring program, a report of findings shall be prepared to document the results of the monitoring program.

Page 371 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-38

4.8 GREENHOUSE GAS EMISSIONS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the
environment?
(b) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of
greenhouse gases?
The analysis presented in the following section is based upon the Air Quality and Greenhouse Gas Emissions Technical Memorandum (AQ/GHG Memo) prepared for the proposed project, which involved emissions modeling using the California Emissions Estimator Model version 2022.1 (CalEEMod) computer program. The AQ/GHG Memo is included within this IS/MND as Appendix A.

Greenhouse Gases (GHGs) are present in the atmosphere naturally, are released by natural sources, or form from secondary reactions taking place in the atmosphere. Over the last 200 years, humans have caused substantial quantities of GHGs to be released into the atmosphere. These extra emissions are increasing GHG concentrations in the atmosphere and enhancing the natural greenhouse effect, which is believed to be causing global warming. Although manmade GHGs include naturally occurring GHGs such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), some gases like hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen trifluoride (NF3), and sulfur hexafluoride (SF6) are completely new to the atmosphere.

Certain gases, such as water vapor, are short-lived in the atmosphere. Others remain in the atmosphere for significant periods of time, contributing to climate change in the long term. Water vapor is excluded from the list of GHGs above because it is short-lived in the atmosphere and its atmospheric concentrations are largely determined by natural processes, such as oceanic evaporation.

These gases vary considerably in terms of Global Warming Potential (GWP), which is a concept developed to compare the ability of each GHG to trap heat in the atmosphere relative to another gas.

The GWP is based on several factors, including the relative effectiveness of a gas to absorb infrared radiation and length of time that the gas remains in the atmosphere (“atmospheric lifetime”). The GWP of each gas is measured relative to CO2, the most abundant GHG; the definition of GWP for a particular GHG is the ratio of heat trapped by one unit mass of the GHG to the ratio of heat trapped by one unit mass of CO2 over a specified time period. GHG emissions are typically measured in terms of pounds or tons of “CO2 equivalents” (CO2e).

State CEQA Guidelines Section 15064(b) provides that the “determination of whether a project may have a significant effect on the environment calls for careful judgment on the part of the public agency involved, based to the extent possible on scientific and factual data,” and further states that an “ironclad definition of significant effect is not always possible because the significance of an activity may vary with the setting.” Currently, there is no Statewide GHG emissions threshold that has been

Page 372 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-39
used to determine the potential GHG emissions impacts of a project. Threshold methodology and thresholds are currently developed and revised by air districts in California.

Impact Analysis
(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.

Construction. Construction activities associated with the proposed project would produce combustion emissions from various sources. Construction would emit GHGs through the operation of construction equipment and from worker and builder supply vendor vehicles for the duration of the approximately 160-day construction period. The combustion of fossil-based fuels creates GHGs such as CO2, CH4, and N2O. Furthermore, the fueling of heavy equipment emits CH4. Exhaust emissions from on-site construction activities would vary daily as construction activity levels change. Table 4.8.A shows CO2e emissions calculations per construction year.

Table 4.8.A: Construction Greenhouse Gas Emissions
Construction Year Greenhouse Gas Emissions, CO2e
(metric tons per year)
Total Project Emissions 463.9
Construction Emissions Amortized over 30 years 15.4
Source: Compiled by LSA (August 2024).

Note: Numbers may not appear to add correctly due to rounding.

CO2e = carbon dioxide equivalent
As indicated in Table 4.8.A, it is estimated that the proposed project would generate 463.9 metric tons of “CO2 equivalents” (MT CO2e) during construction. When amortized over the 30-year life of the proposed project, annual emissions would be 15.4 MT CO2e. As indicated above, the South Coast Air Quality Management District (SCAQMD) does not have an adopted threshold of significance for construction-related GHG emissions. However, lead agencies are required to quantify and disclose GHG emissions that would occur during construction. The SCAQMD then recommends that construction GHG emissions be amortized over the life of the project (defined as 30 years), added to the operational emissions, and compared to the applicable GHG significance threshold tier. However, as further discussed below, the operational activities associated with the proposed project would not be expected to increase over the baseline existing levels of activity. Construction emissions are temporary and would cease to occur after the construction period; therefore, the proposed project would not result in the generation of substantial GHG emissions associated with demolition and construction activities.

Operation. Long-term GHG emissions are typically generated from mobile sources (e.g., cars, trucks, and buses), area sources (e.g., maintenance activities and landscaping), and indirect emissions from sources associated with energy consumption. The proposed project would generate mobile-source GHG emissions from project-generated vehicle and truck trips traveling to and from the project limits.

Area-source emissions would be associated with activities such as landscaping and maintenance within the project limits. Energy source emissions would be associated with street lighting.

Page 373 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-40
As discussed in Chapter 2.0, Project Description, of this IS/MND, the proposed project would improve an approximately 0.28-mile segment of the intersections of Yorba Linda Boulevard and Imperial Highway and Yorba Linda Boulevard and Lakeview Avenue. Improvements would include modifications to the eastbound and westbound lanes on Yorba Linda Boulevard, the proposed lane reconfigurations, modifications to the northerly and southerly curb lines, restriping, and modifications to existing medians, sidewalks, and utilities, as well as current and proposed locations of relevant streetscape features. As discussed in the Traffic Impact Analysis29 prepared for the proposed project, upon competition of construction activities, operation of the proposed project would not result in a significant traffic impact at the study intersections and the Level of Service (LOS) traffic designation would remain the same as with the existing conditions. In addition, the three additional turn lanes being proposed would not be expected to add through capacity. Therefore, no additional trips are anticipated due to implementation of the proposed project. As such, the project would not result in an increase in the generation of vehicle trips or vehicle miles traveled (VMT) that would increase air pollutant emissions. The proposed project would also modify the existing traffic signals to account for the proposed turn lanes; however, this energy use is expected to be minimal during the operational period and similar to existing conditions. In addition, streetlights would be retrofitted with light emitting diode (LED) bulbs upon their re-installation along the new median, which would have a lower energy usage than the bulbs currently being used within the project limits. Furthermore, utility relocations would not result in a substantial source of energy and water source emissions. After relocation, the proposed project would operate similar to existing conditions. Therefore, the project would not be a substantial source of energy, area, waste, or water source emissions, or generate GHG emissions that would have a significant impact on the environment. Impacts would be less than significant, and no mitigation is required.
(b) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases?
Less Than Significant Impact. The AQ/GHG Memo analyzed the proposed project for consistency with the goals of the California Air Resources Board (CARB) 2022 Scoping Plan and the Southern California Association of Governments (SCAG) Connect SoCal 2024 Regional Transportation Plan/Sustainable Communities Strategy (Connect SoCal 2024).
2022 Scoping Plan. The following discussion evaluates the proposed project according to the goals of the 2022 Scoping Plan, Executive Order (EO) B-30-15, Senate Bill (SB) 32, Assembly Bill (AB) 197, and AB 1279.

EO B-30-15 added the immediate target of reducing GHG emissions to 40 percent below 1990 levels by 2030. CARB released a second update to the Scoping Plan, the 2017 Scoping Plan,30 to reflect the 2030 target set by EO B-30-15 and codified by SB 32. SB 32 affirms the importance of addressing climate change by codifying into statute the GHG emissions reductions target of at least 40 percent below 1990 levels by 2030 contained in EO B-30-15. SB 32 builds on AB 32 and keeps California on the path toward achieving its Statewide 2050 objective of reducing emissions to 80 percent below 1990 levels. The companion bill to SB 32, AB 197, provides additional direction to the CARB related to the 29 BKF Engineers, Inc. Yorba Linda Widening Traffic Impact Study. January 2024. 30 California Air Resources Board (CARB). 2017. California’s 2017 Climate Change Scoping Plan. November.

Page 374 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-41
adoption of strategies to reduce GHG emissions. Additional direction in AB 197 intended to provide easier public access to air emissions data that are collected by CARB was posted in December 2016.

In addition, the 2022 Scoping Plan assesses progress toward the statutory 2030 target, while laying out a path to achieving carbon neutrality no later than 2045. The 2022 Scoping Plan focuses on outcomes needed to achieve carbon neutrality by assessing paths for clean technology, energy deployment, natural and working lands, and others, and is designed to meet the State’s long-term climate objectives and support a range of economic, environmental, energy security, environmental justice, and public health priorities.

The 2022 Scoping Plan focuses on building clean energy production and distribution infrastructure for a carbon-neutral future, including transitioning existing energy production and transmission infrastructure to produce zero-carbon electricity and hydrogen, and utilizing biogas resulting from wildfire management or landfill and dairy operations, among other substitutes. The 2022 Scoping Plan states that in almost all sectors, electrification will play an important role. The 2022 Scoping Plan evaluates clean energy and technology options and the transition away from fossil fuels, including adding four times the solar and wind capacity by 2045 and about 1,700 times the amount of current hydrogen supply. As discussed in the 2022 Scoping Plan, EO N-79-20 requires that all new passenger vehicles sold in California will be zero-emission by 2035, and all other fleets will have transitioned to zero-emission as fully possible by 2045, which will reduce the percentage of fossil fuel combustion vehicles.

Energy efficient measures are intended to maximize energy efficiency building and appliance standards, pursue additional efficiency efforts including new technologies and new policy and implementation mechanisms, and pursue comparable investment in energy efficiency from all retail providers of electricity in California. In addition, these measures are designed to expand the use of green building practices to reduce the carbon footprint of California’s new and existing inventory of buildings. The proposed project would also modify the existing traffic signals to account for the proposed turn lanes; however, this energy use is expected to be minimal during the operational period and similar to existing conditions. In addition, streetlights would be retrofitted with energy-efficient LED bulbs upon their re-installation along the new median. Therefore, the proposed project would not conflict with applicable energy measures.

Water conservation and efficiency measures are intended to continue efficiency programs and use cleaner energy sources to move and treat water. Increasing the efficiency of water transport and reducing water use would reduce GHG emissions. The project would not be a substantial source of water source emissions. Therefore, the proposed project would not conflict with any of the water conservation and efficiency measures.

The goal of transportation and motor vehicle measures is to develop regional GHG emissions reduction targets for passenger vehicles. Specific regional emission targets for transportation emissions would not directly apply to the proposed project. The second phase of Pavley standards is currently in effect to reduce GHG emissions from new cars by 34 percent from 2016 levels by 2025.

As identified above, no additional trips are anticipated due to implementation of the proposed project. Therefore, the proposed project would not conflict with the identified transportation and motor vehicle measures presented in the 2022 Scoping Plan.

Page 375 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-42
Connect SoCal 2024. SCAG’s Connect SoCal 2024 identifies land use strategies that focus on new housing and job growth in areas served by high quality transit and other opportunity areas that would be consistent with a land use development pattern that supports and complements the proposed transportation network. The core vision in Connect SoCal 2024 is to better manage the existing transportation system through design management strategies, integrate land use decisions and technological advancements, create complete streets that are safe to all roadway users, preserve the transportation system, and expand transit and foster development in transit oriented communities.

Connect SoCal 2024 contains transportation projects to help more efficiently distribute population, housing, and employment growth, as well as forecast development that is generally consistent with regional-level general plan data. The forecasted development pattern, when integrated with the financially constrained transportation investments identified in the 2020–2045 RTP/SCS, would reach the regional target of reducing GHG emissions from autos and light-duty trucks by 19 percent by 2035 (compared to 2005 levels). Connect SoCal 2024 does not require that local General Plans, Specific Plans, or zoning be consistent with Connect SoCal 2024, but provides incentives for consistency for governments and developers.

Implementing Connect SoCal 2024 will greatly reduce the regional GHG emissions from transportation, helping to achieve statewide emissions reduction targets. The proposed project does not meet the criteria identified in State CEQA Guidelines Section 15205.b.2 (Projects of Statewide, Regional, or Areawide Significance) for projects of statewide, regional, or areawide significance. In addition, the proposed project would not require a change to the City’s current General Plan land use designations or current zoning, and would therefore be consistent with the City’s General Plan and Zoning Ordinance. As such, the proposed project would not interfere with SCAG’s ability to achieve the region’s GHG reduction target of 19 percent below 2005 per capita emissions levels by 2035.

Furthermore, the proposed project is not regionally significant per State CEQA Guidelines Section 15206 and as such, it would not conflict with the targets set forth in SCAG’s Connect SoCal 2024 since those targets were established and are applicable on a regional level.

Based on the nature of the proposed project, it is anticipated that implementation of the proposed project would not conflict with identified transportation and motor vehicle measures presented in the 2022 Scoping Plan, and would not interfere with SCAG’s ability to implement the regional strategies outlined in Connect SoCal 2024. Impacts pertaining to conflict with applicable GHG-related plans would therefore be less than significant, and no mitigation is required.

Page 376 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-43

4.9 HAZARDS AND HAZARDOUS MATERIALS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?
(b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident
conditions involving the release of hazardous materials into the environment?
(c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within onequarter mile of an existing or proposed school? (d) Be located on a site which is included on a list of hazardous materials sites complied pursuant to Government Code
Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment?
(e) For a project located 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?
(f) Impair implementation of or physically interfere with an adopted emergency response plan or emergency
evacuation plan?
(g) Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires?
Impact Analysis
(a) Would the project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?
Less Than Significant Impact. Hazardous materials are chemicals that could potentially cause harm during an accidental release or mishap, and are defined as being toxic, corrosive, flammable, reactive, and an irritant or strong sensitizer.31Hazardous substances include all chemicals regulated under the United States Department of Transportation’s (USDOT) “hazardous materials” regulations and the United States Environmental Protection Agency (USEPA) “hazardous waste” regulations. Hazardous wastes require special handling and disposal because of their potential to damage public health and the environment. The probable frequency and severity of consequences from the routine transport, use, or disposal of hazardous materials are affected by the type of substance, the quantity used or managed, and the nature of the activities and operations. 31 A “sensitizer” is a chemical that can cause a substantial proportion of people or animals to develop an allergic reaction in normal tissue after repeated exposure to a chemical (United States Department of Labor 2017).

Page 377 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-44
The proposed project is a roadway improvement project and would not involve the routine transport, use, or disposal of hazardous materials. No manufacturing, industrial, or other uses that handle large amounts of hazardous materials would occur within the project limits. Operations of the proposed project would be limited to vehicular use of the roadway, which would involve minimal amounts of hazardous materials.

During construction of the proposed project, hazardous materials such as fuel, lubricants, paint, sealants, and adhesives would be transported and used within the project limits. The proposed project would be required to comply with federal, State, and local regulations regarding the transportation, use, and disposal of hazardous materials, including preparation and implementation of a Storm Water Pollution Prevention Plan (SWPPP) that requires implementation of control measures for hazardous materials releases in order to prevent contaminated runoff into nearby storm collection systems or waterways. Compliance with existing regulations and implementation of the SWPPP during construction would ensure that potential impacts associated with hazardous materials use, transport, and disposal are considered less than significant, and no mitigation is required. (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. The potential for releasing hazardous materials into the environment would be limited to construction of the proposed project as well as vehicles on the roadway during operations. As previously stated, compliance with existing regulations and implementation of the SWPPP would reduce the potential for the release of hazardous materials during construction of the proposed project. Regardless, if a hazardous release were to occur, it would not be anticipated to result in a significant hazard to the public, surrounding land uses, or environment due to the small quantities of these materials associated with construction activities.

The potential associated with vehicular use of the roadway exists under current conditions and would not be substantially greater under the proposed project. Vehicles and trucks may transport hazardous substances that could spill and impact the roadway, adjacent properties, or resources. However, transport of hazardous materials is subject to strict regulations established by local police and fire departments trained in emergency response procedures for safely responding to accidental spills of hazardous substances on public roads, which further reduces impacts. Therefore, impacts of the proposed project associated with hazards from reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment would be similar to existing conditions and are considered 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? Less Than Significant Impact. The closest school to the project limits is Friends Christian Academy, located approximately 0.13 mile south of Yorba Linda Boulevard at 5151 Lakeview Avenue. As previously stated, the proposed project is a transportation improvement project and is not anticipated to involve the routine transport, use, or disposal of hazardous materials. As such, the proposed project would result in less than significant impacts related to hazardous emissions or handling of hazardous or acutely hazardous materials, substances, or waste within 0.25 mile of an existing or proposed school, and no mitigation is required.

Page 378 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-45
(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 Section 65962.5, or the Cortese List Statute, states that the California Department of Toxic Substances Control (DTSC) shall compile and maintain annually a list (Cortese List) of hazardous waste facilities subject to corrective action as part of the Health and Safety Code. This list is commonly referred to as the Cortese List. Cortese List data resources include the DTSC EnviroStor database, the State Water Resources Control Board (SWRCB) GeoTracker database, and other resources identified by the California Environmental Protection Agency (CalEPA).32
According to the DTSC EnviroStor database, the project limits are not located on a federal Superfund site, State response site, voluntary cleanup site, evaluation site, school or military investigation site, tiered permit site, or corrective action site.33 The closest site listed on EnviroStor to the project limits is the Lakeview Shopping Center/Lido Cleaners site, located 0.08 mile north of Yorba Linda Boulevard.

This site was marked as an Evaluation in July 2001 and is not considered an active cleanup site.

Further, several intervening structures exist between the Lido Cleaners site and the project limits. As such, a search of the EnviroStor database did not identify any active cleanup sites in the vicinity of the project limits that would create a significant hazard to the public or the environment.

A review of the SWRCB GeoTracker database indicated that several former Leaking Underground Storage Tank (LUST) cleanup sites exist within the vicinity of the project limits. 34 The closest LUST to
the project limits is the Shell Oil site, located directly north of Yorba Linda Boulevard at 18503 Yorba Linda Boulevard. This site has been marked as “completed – case closed” as of August 12, 2015.

Another LUST cleanup site located within a 0.25-mile radius of the project limits is the Tosco – 76 Site #5930, located approximately 0.06 mile north of Yorba Linda Boulevard at 18351 Imperial Highway.

This site is also considered “completed – case closed” as of April 1, 2016. Other LUST cleanup sites, cleanup program sites, military cleanup sites, military privatized sites, or military Underground Storage Tank (UST) sites within the project limits’ vicinity are all marked as “completed – case closed” and therefore do not pose an active hazard to the project limits. The project limits are also not located on a list of solid waste disposal sites identified by the SWRCB with waste constituents above hazardous waste levels outside the waste management unit35 or active cease and desist orders and cleanup and abatement orders.
36 32 California Environmental Protection Agency (CalEPA). 2024. Cortese List Data Resources. Website:
https://calepa.ca.gov/sitecleanup/corteselist/ (accessed January 17, 2024). 33 California Department of Toxic Substances Control (DTSC). EnviroStor Database. Website: https://www. envirostor.dtsc.ca.gov/public/ (accessed April 5, 2024). 34 California State Water Resources Control Board (SWRCB). GeoTracker Database. Website: https://geo tracker.waterboards.ca.gov/ (accessed April 5, 2024). 35 California Environmental Protection Agency (CalEPA). n.d. Sites Identified with Waste Constituents Above Hazardous Waste Levels Outside the Waste Management Unit. Website: https://calepa.ca.gov/wpcontent/uploads/sites/6/2016/10/SiteCleanup-CorteseList-CurrentList.pdf (accessed April 5, 2024). 36 California Environmental Protection Agency (CalEPA). n.d. List of “Active” CDO and CAO from Water Board (accessed April 5, 2024).

Page 379 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-46
Ultimately, the potential for adverse environmental impacts to the project limits from any of the offsite facilities identified above are considered low due to distance from the project limits, intervening land uses, and inactive/closed status of the cases. Because of the findings discussed above and because the project limits are not located on any of the Cortese List databases, impacts related to this topic are considered less than significant. No mitigation is required. (e) Would the project be located within an airport land use plan or, where such a plan has not been adopted, within 2 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 project limits are not located within the vicinity of a public or private airport. The closest airport to the project limitsis Fullerton Municipal Airport, a commercial service airport located approximately 9.7 miles west of the project limits. Further, the project limits are not located within an airport impact zone based on the Airport Environs Land Use Plan (AELUP) for Fullerton Municipal Airport.37 In addition, the proposed project is not located in the vicinity of a private airstrip. The proposed project is a transportation improvement project and would not involve the introduction of residential or employment uses in the project limits. Therefore, the proposed project would not result in any safety or noise impacts to people residing or working within 2 miles of a public airport or public use airport. Therefore, no impacts to airport land uses would occur, and no mitigation is required. (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 City’s Know Your Way program establishes 28 neighborhoodspecific evacuation zones within the City, each with identified neighborhood exits. The project limits fall within the following three zones: 24 (Avocado and Mountain View), 25 (Nixon), and 26 (Highland and Lakebed).38 According to maps of each zone, several neighborhood exits fall along Yorba Linda Boulevard within the project limits. However, the City acknowledges that specific evacuation routes and procedures are difficult to predict and would be dependent on the characteristics of each emergency event.

Under current conditions, Yorba Linda Boulevard has two closely spaced intersections, with Imperial Highway and Lakeview Avenue. The signalized intersection of Imperial Highway/Yorba Linda Boulevard is located approximately 500 feet west of the signalized intersection of Lakeview Avenue/ Yorba Linda Boulevard. Driveways for shopping areas west of Imperial Highway create further closely spaced intersections along Yorba Linda Boulevard. As a result, limited space is available to provide storage for turning movements, and stacking can occur, which would impede emergency access and/ or evacuation flows. As previously stated, the proposed project would reduce queuing and stacking issues within the project limits through the proposed turn-lane additions and roadway realignment.

Therefore, once the proposed project is operational, emergency access and potential movement of 37 Airport Land Use Commission (ALUC). 2008. Airport Environs Land Use Plan for John Wayne Airport (AELUP).

Website: https://files.ocair.com/media/2021-02/AELUP%20for%20FMA%2005092019.pdf (accessed March 8, 2024). 38 City of Yorba Linda. n.d. Evacuation Zones. Website: https://www.yorbalindaca.gov/868/Evacuation-Zones (accessed April 5, 2024).

Page 380 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-47
evacuation-related traffic along Yorba Linda Boulevard, Imperial Highway, and Lakeview Avenue would be equivalent to or improved compared to existing conditions.

The proposed project would achieve continued mobility along Yorba Linda Boulevard during the construction phase through the use of temporary lane closures and lane shifts. These shifts could result in temporary delays but would allow the roadway to remain open the entire duration of the proposed project’s construction. Therefore, the proposed project would have less than significant impacts pertaining to the implementation of an emergency response or evacuation plan. No mitigation is required.
(g) Would the project expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires?
No Impact. Please refer to Section 4.20, Wildfire, for a detailed description of the proposed project’s potential impacts related to wildland fires. As discussed in Section 4.20, the entirety of the project limits is not designated as at risk of wildland fire hazards. The only areas within the City of Yorba Linda categorized as at risk are the undeveloped hillsides along the City’s northern and northeastern boundaries, the closest of which are located approximately 1.6 miles away from the project limits. 39 Further, the project limits are located within a developed area and do not introduce any new inhabitable structures or include any characteristics that could be exposed to increased risks of wildland fires. Improvements proposed under the project include road widening, median and curb modifications, restriping, utility relocations, and construction of a new retaining wall. However, these features would not substantially increase the scale of the project limits’ development from existing conditions, and would not exacerbate the fire risk of the project limits. Further, the project limits are generally flat, within an urbanized portion of the City, and lack combustible materials and vegetation necessary for the uncontrolled spread of a wildfire. Overall, due to the project limits’ characteristics and distance from the nearest wildland fire hazard area, the proposed project would have no impacts related to wildland fires. No mitigation is required.
39 California Department of Forestry and Fire Protection (CAL FIRE). 2022. Fire Hazard Severity Zone (FHSZ) Viewer. Website: https://egis.fire.ca.gov/FHSZ/ (accessed February 21, 2024).

Page 381 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-48

4.10 HYDROLOGY AND WATER QUALITY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or groundwater quality?
(b) Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the
project may impede sustainable groundwater management
of the basin?
(c) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious
surfaces, in a manner which would:
i. result in substantial erosion or siltation on- or offsite; ii. substantially increase the rate or amount of surface runoff in a manner which would result in flooding onor 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; or
iv. impede or redirect flood flows?
(d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation?
(e) Conflict with or obstruct implementation of water quality control plan or sustainable groundwater management
plan?
Impact Analysis
The analysis contained in the following section is based upon the information presented in the Water Quality Management Plan (WQMP) prepared for the proposed project in April 2024 and included as Appendix F of this IS/MND.
(a) Would the project violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or groundwater quality? Less Than Significant Impact. The project limits are located within the Santa Ana River Watershed, which encompasses an approximately 2,650-square-mile area including portions of Orange, Riverside, and San Bernardino Counties, as well as a sliver of Los Angeles County.40 The Santa Ana River drains the largest coastal stream system in Southern California and ultimately discharges into the Pacific Ocean. The Santa Ana River Watershed is located within the jurisdiction of the State Water Resources Control Board (SWRCB) and the Santa Ana Regional Water Quality Control Board (RWQCB), one of the nine RWQCBs that regulate the quality of surface water and groundwater bodies throughout 40 Santa Ana Watershed Project Authority. 2014. One Water One Watershed 2.0 Plan. February. Website:
https://sawpa.gov/owow/owow-irwm-plans/owow-2-0-plan/ (accessed April 26, 2024).

Page 382 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-49
California.41 The Santa Ana RWQCB is responsible for implementation of a Water Quality Control Plan (Basin Plan), which establishes beneficial water uses and water quality objectives for waterways and water bodies within the region.

Under current conditions, the project limits are fully developed and currently consist of a six-lane divided roadway fitted with tiled and landscaped medians as well as curb areas containing landscaping, driveways, and pedestrian sidewalks.

Stormwater from the project limits drains to a catch basin inlet on the northern curb of Yorba Linda Boulevard just west of the roadway’s intersection with Imperial Highway, four catch basin inlets along the curbs of Imperial Highway just north of the project limits, or one catch basin inlet on the northeastern curb of the intersection of Yorba Linda Boulevard and Lakeview Avenue. As such, the project limits are served by six catch basin inlets either within or just beyond the project limits.

Stormwater draining to these inlets eventually discharge to the Santa Ana River.

Stormwater runoff is regulated by the National Pollutant Discharge Elimination System (NPDES) Program (established through the federal Clean Water Act [CWA]). The objective of the NPDES Program is to control and reduce pollutant discharges to surface water bodies. Compliance with NPDES permits is mandated by State and federal statutes and regulations. Locally, the NPDES Program is administered by the Santa Ana RWQCB. Construction activities are subject to the SWRCB NPDES General Permit for Stormwater Discharges Associated with Construction and Land Disturbance Activities, Order No. 2022-0057-DWQ, NPDES No. CAS000002 (Construction General Permit). Any construction activity, including grading, that would result in the disturbance of 1 acre or more, would require compliance with SWRCB’s Construction General Permit, which requires preparation of a Stormwater Pollution Prevention Plan (SWPPP) and implementation of Construction Best Management Practices (BMPs) to address water quality concerns during construction activities.

Construction BMPs include, but are not limited to, Erosion Control and Sediment Control BMPs designed to minimize erosion and retain sediment on site as well as Good Housekeeping BMPs to prevent spills, leaks, and discharge of construction debris and waste into receiving waters.

Operational activities of the proposed project would be subject to the NPDES Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems (MS4s) Draining the Watersheds Within the Orange County Region, Order No. R8-2009-0030, NPDES No.

CAS618030 as amended by Order No. R8-2010-0062 (MS4 Permit). The MS4 Permit prohibits discharges, sets limits on pollutants being discharged into receiving waters, and requires implementation of technology-based standards. The MS4 Permit requires co-permittees, including the City of Yorba Linda, to develop and implement standard design and post-development BMP guidance for the application of Low Impact Development (LID) BMPs to the maximum extent practicable. The MS4 Permit also requires preparation of a Water Quality Management Plan (WQMP), implementation of post-construction BMPs, and hydromodification requirements for new development and significant redevelopment projects that qualify as “Priority Development” projects.

Section 16.04 of the City of Yorba Linda Municipal Code codifies requirements related to water quality and stormwater discharges, and is intended to enhance and protect water quality by prescribing 41 State Water Resources Control Board (SWRCB). n.d. About the Water Boards. Website: https://www.water boards.ca.gov/board_reference/docs/about_the_waterboards.pdf (accessed April 26, 2024).

Page 383 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-50
requirements for all new development and significant redevelopment projects in order to reduce pollution in surface runoff. Chapter 16.04 includes, but is not limited to, general provisions, prohibited discharges, BMP requirements, and monitoring and inspection procedures related to water quality.

Section 16.04 requires that new development projects and significant redevelopment projects adhere to the City’s Local Implementation Plan (LIP) prepared as part of a compliance program to satisfy the requirements of the area-wide Drainage Area Management Plan (DAMP) and the Santa Ana RWQCB.

The LIP outlines citywide protocols for projects to implement in order to contribute to regional stormwater pollution control efforts and adhere to the requirements of applicable NPDES permits described above. In addition, Section 16.04 requires that all new development and significant redevelopment projects be undertaken in accordance with a WQMP, as prepared in accordance with the MS4 Permit. Chapter 16.04 also lists several BMP requirements to be implemented during construction of any project, regardless of “Priority” status, including minimizing the size and exposure time of disturbed soil areas, stabilizing all slopes, and utilizing sediment controls.

Construction. The proposed project would include a variety of roadway improvements along an

0.28-mile segment of the Yorba Linda Boulevard roadway including lane conversions, additional lanes, curb modifications, median modifications, traffic signal modifications, utility relocations, restriping, and retaining wall construction. Pollutants of concern that would be anticipated during construction include sediments, trash, petroleum products, concrete waste (dry and wet), sanitary waste, and chemicals typically used during construction activities. Each of these pollutants on its own or in combination with other pollutants can have a detrimental effect on water quality. During construction activities, excavated soil would be exposed, and there would be an increased potential for soil erosion and sedimentation compared to existing conditions. In addition, chemicals, liquid products, petroleum products (e.g., paints, solvents, and fuels), and concrete-related waste have the potential to be transported via stormwater runoff into receiving waters if spilled or leaked during construction activities. Construction activities associated with the proposed project would result in the total disturbance of 1.32 acres of soil.

Because construction of the proposed project would disturb greater than 1 acre of soil, the project is subject to the requirements of the Construction General Permit, as specified in Regulatory Compliance Measure (RCM) HYD-1, as detailed below. The Construction General Permit requires preparation of a SWPPP and implementation of construction BMPs during construction activities. Construction BMPs would include, but are not limited to, Erosion Control and Sediment Control BMPs designed to minimize erosion and retain sediment on site as well as Good Housekeeping BMPs to prevent spills, leaks, and discharge of construction debris and waste into receiving waters. As specified in RCM HYD1, and as required by the Construction General Permit, the Construction Contractor would be required to prepare a SWPPP and implement construction BMPs detailed in the SWPPP during construction activities.

The proposed project would also be required to comply with Chapter 16.04, Water Quality Control, of the City’s Municipal Code, as specified in RCM HYD-2, detailed below, which is intended to enhance and protect water quality by prescribing requirements for all new development and redevelopment projects designed to reduce pollution in surface runoff. As previously stated, Chapter 16.04 includes, but is not limited to, general provisions, prohibited discharges, BMPs, and monitoring and inspection procedures, including implementation of construction BMPs to manage the surface runoff from the construction site. As specified in RCM HYD-2, the proposed project would be required to comply with

Page 384 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-51
all applicable procedures and requirements set forth in Chapter 16.04 of the City’s Municipal Code, which would ensure consistency with the City’s overarching policies pertaining to stormwater quality.

According to the Geotechnical Evaluation prepared for the proposed project by Ninyo & Moore in September 2023, no groundwater was encountered in the exploratory borings to a depth of 41.5 feet below ground surface (bgs). The maximum depth of excavation to construct project features is anticipated to reach approximately 32 feet bgs. Therefore, groundwater dewatering is not anticipated during construction activities and groundwater quality would not represent a substantial concern under the proposed project. However, in the unlikely event that groundwater or perched groundwater is encountered during construction, it would be necessary to obtain coverage under the NPDES Waste Discharge Requirements (WDR) Permit for Discharges to Surface Waters That Pose an Insignificant (De Minimis) Threat to Water Quality (Groundwater Discharge Permit) (Order No. R8- 2020-0006, NPDES No. CAG998001), as specified in RCM HYD-3. The Groundwater Discharge Permit would require testing and treatment (as necessary) during groundwater dewatering prior to release to surface waters to ensure that discharges do not exceed water quality limits specified in the permit.

With adherence to RCM HYD-3, groundwater dewatering, if necessary during construction activities, would not introduce pollutants to receiving waters at levels that would violate water quality standards or water discharge requirements, degrade water quality, or alter the quality of the receiving water.

Infiltration of stormwater has the potential to affect groundwater quality in areas of shallow groundwater. As discussed above, groundwater was not encountered within the project limits in exploratory borings to a depth of 41.5 feet.

Pollutants in stormwater are generally removed by soil through absorption as water infiltrates. In areas of deep groundwater, there is more absorption potential and, as a result, less potential for pollutants to reach groundwater. Due to the depth and potential presence of groundwater, it is not expected that any stormwater that may infiltrate during construction would affect groundwater quality because there is not a direct path for pollutants to reach groundwater. Therefore, project construction activities would not substantially degrade groundwater quality.

With implementation of RCM HYD-1, RCM HYD-2, and RCM HYD-3, which require adherence to the Construction General Permit, City Municipal Code Chapter 16.04, and the Groundwater Discharge Permit, construction impacts related to surface water quality standards, waste discharge requirements, and surface water quality would be less than significant, and no mitigation is required.

Operation. The proposed project would improve an approximately 0.28-mile segment of the Yorba Linda Boulevard roadway including lane conversions, additional lanes, curb modifications, median modifications, traffic signal modifications, utility relocations, restriping, and retaining wall construction.

According to the WQMP prepared for the proposed project, stormwater from the project limits drains from east to west from the beginning of the project limits to approximately 150 feet east of the Lakeview Avenue intersection. The project drains from west to east from approximately 150 feet east of the Yorba Linda Boulevard/Lakeview Avenue intersection to the easterly end of the project limits.

In general, both Imperial Highway and Lakeview Avenue tend to drain from north to south.

Page 385 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-52
This stormwater drains to one of eight catch basin inlets, as described below:
• Along the northern curb of Yorba Linda Boulevard (approximately 80 feet west of the Imperial Highway intersection);
• Along both curbs of Imperial Highway (approximately 75 feet north of the Yorba Linda Boulevard intersection);
• Along the eastern curb of Imperial Highway (approximately 200 feet south of the Yorba Linda Boulevard intersection);
• Along the eastern curb of Lakeview Avenue (approximately 15 feet north of the Yorba Linda Boulevard intersection);
• Along the eastern curb of Lakeview Avenue (approximately 200 feet south of the Yorba Linda intersection); and
• Along both sides of Yorba Linda Avenue (approximately 550 feet east of the Lakeview Avenue intersection).

As such, stormwater originating within the project limits would be potentially served by eight catch basin inlets as described above. Stormwater draining to these inlets eventually discharge to the Santa Ana River.

Existing catch basins that would be affected by the proposed curb realignment would be reconstructed as necessary in similar locations. Specifically, the existing catch basin on the north side of Yorba Linda Boulevard west of Imperial Highway in front of the Mimi’s Café Restaurant would be shifted to align with the proposed curb position. In addition, two new biofiltration devices would be installed within the project limits. Specifically, two new Contech Filterra Biotreatment devices would be installed within the project limits to treat stormwater; one along Imperial Highway just north of Yorba Linda Boulevard and one along Yorba Linda Boulevard near the easternmost project limits.

These devices use engineered filters and natural components such as mulch, organic material, and plants in order to treat potential pollutants and nutrients contained in stormwater as it percolates.

As such, potentially polluted stormwater would be treated by the proposed biofiltration devices prior to infiltration and would not introduce pollutants to existing groundwater supplies.

Section 303(d) of the federal CWA requires that States identify water bodies, including bays, rivers, streams, creeks, and coastal areas, which do not meet water quality standards and the pollutants that are causing the impairment. Total Maximum Daily Loads (TMDLs) describe the maximum amount of a pollutant that a water body can receive while still meeting established water quality standards. A TMDL establishes limits for pollutant discharges into impaired water bodies. According to the SWRCB Surface Water Quality Assessment 2020-2022 Integrated Report for Clean Water Act Sections 303(d) and 305(b), the portion of the Santa Ana River impacted by the subject project (Pacific Ocean to Prado Dam – Reach 1 – Tidal Prism to 17th Street and Reach 2 – 17th Street to Prado Dam) is not listed as

Page 386 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-53
an impaired water body.42 Therefore, under existing conditions, stormwater from the project limits does not discharge to CWA Section 303(d) impaired water bodies.

The proposed project would result in a net increase of 0.13 acre of impervious surface area within the project limits. As such, the proportion of impervious surface area to pervious surface area within the project limits would increase from 95.35 percent to 98.11 percent. This increase in impervious surface area would slightly increase the volume of runoff during a storm, which would increase the potential for pollutants to discharge into downstream receiving waters, including the Santa Ana River and the Pacific Ocean. Pollutants of concern from long-term operations of the proposed project include suspended solids/sediment, nutrients, oil and grease, metals, and trash and debris.

The City of Yorba Linda is a co-permittee under the MS4 Permit. As previously discussed, the MS4 Permit requires the preparation of project-specific WQMPs for “Priority Development” projects. The MS4 Permit prohibits discharges, sets limits on pollutants being discharged into receiving waters, and requires implementation of technology-based standards. The MS4 Permit requires co-permittees, including the City, to develop and implement standard design and post-development LID BMPs to the maximum extent practicable. The MS4 Permit also requires preparation of a WQMP, implementation of post-construction BMPs, and hydromodification requirements for new development and significant redevelopment projects that qualify as “Priority Development” projects. As specified in RCM HYD-4, the proposed project would adhere to prepare a WQMP in accordance with the OC Public Works Technical Guidance Document for the Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans (WQMPs), as well as the other guidance documents specified in RCM HYD-4.43 The WQMP would identify all feasible and applicable BMPs. The biofiltration devices previously described represent an example of a BMP that would be incorporated into the proposed project.

In addition, Chapter 16.04 requires development projects to comply with all applicable BMPs set forth in the Orange County DAMP and the City of Yorba Linda LIP. As previously discussed, the DAMP is the principal guidance and compliance document for the county-wide implementation of the Stormwater Program. It is the foundation for each Orange County Stormwater Permittee to implement programs designed to prevent pollutants from entering receiving waters to the maximum extent practicable.

Chapter 7 of the City’s LIP provides the description and details of the City's water quality program pertaining to new development and redevelopment. This chapter provides examples of Source Control, Site Design, and LID BMP requirements for such projects, such as storm drain signage, minimizing impervious surfaces, efficient irrigation systems and landscape design, and landscaped areas designed to infiltrate and/or treat runoff.44 As detailed in RCM HYD-2, the proposed project 42 State Water Resources Control Board (SWRCB). 2023. 2020-2022 California Integrated Report (Clean Water Act Section 303(d) List and 305(b) Report). Website: https://www.waterboards.ca.gov/water_issues/ programs/water_quality_assessment/2020_2022_integrated_report.html (accessed April 29, 2024). 43 OC Public Works (OCPW). 2013. Technical Guidance Document (TGD) for the Preparation of Conceptual/ Preliminary and/or Project Water Quality Management Plans (WQMPs). September. Website:
https://ocds.ocpublicworks.com/sites/ocpwocds/files/2021-06/OC_TGD%2812-20-2013%29.pdf (accessed January 23, 2024). 44 City of Yorba Linda. 2003, Revised in 2024. Local Implementation Plan - Stormwater Program. July. Website:
https://pub-yorbalinda.escribemeetings.com/filestream.ashx?DocumentId=18391 (accessed April 30, 2024).

Page 387 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-54
would be required to be consistent with the DAMP and implement these programs during project operations where applicable and feasible.

According to the Geotechnical Evaluation prepared for the proposed project by Ninyo & Moore in September 2023, no groundwater was encountered in the exploratory borings to a depth of 41.5 feet bgs. While infiltration of stormwater could have the potential to affect groundwater quality in areas of shallow groundwater, this depth is not considered shallow. Under existing conditions, the majority of the project limits consists of impervious surface area, and the potential for infiltration is limited to areas with ornamental landscaping. Based on the existing conditions and the depth to groundwater, it is not expected that any stormwater that may infiltrate during operation of the proposed project would affect groundwater quality because there would be no direct path for pollutants to reach groundwater. Therefore, operation of the proposed project would not substantially degrade groundwater quality.

With implementation of RCM HYD-2 and RCM HYD-4, which require adherence to City Municipal Code Chapter 16.04 and the MS4 Permit, including implementing operational BMPs where applicable to address pollutants of concern in stormwater runoff, impacts associated with the violation of water quality standards or waste discharge requirements, or degradation of surface water or groundwater quality, during project operation would be less than significant, and no mitigation is required.

Regulatory Compliance Measures
RCM HYD-1 Construction General Permit. Prior to commencement of construction activities, the City of Yorba Linda (City) Public Works Department, and the “selected Contractor” shall obtain coverage under the State Water Resources Control Board (SWRCB) National Pollutant Discharge Elimination System (NPDES) General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities (Order No. 2022-0057-DWQ, National Pollutant Discharge Elimination System No. CAS000002) (Construction General Permit). This shall include submission of Permit Registration Documents (PRDs), including a Notice of Intent (NOI) for coverage under the permit to the SWRCB via the Stormwater Multiple Application and Report Tracking System (SMARTS). The City of Yorba Linda Public Works Department shall demonstrate proof of coverage under the Construction General Permit. Project construction shall not be initiated until a WDID is received from the SWRCB and is provided to the City, or designee.

A Stormwater Pollution Prevention Plan (SWPPP) shall be prepared and implemented for the proposed project in compliance with the requirements of the Construction General Permit. The SWPPP shall identify construction Best Management Practices (BMPs) to be implemented to ensure that the potential for soil erosion and sedimentation is minimized and to control the discharge of pollutants in stormwater runoff as a result of construction activities. Upon completion of construction activities and stabilization of the project limits, a Notice of Termination shall be submitted via SMARTS.

Page 388 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-55
RCM HYD-2 City Municipal Code Chapter 16.04. During and post-construction, the Construction Contractor shall comply with Chapter 16.04, Water Quality Control, of the City of Yorba Linda Municipal Code.

Prior to construction, the Construction Contractor shall submit to and obtain the approval of the City Engineer of a Water Quality Management Plan (WQMP).

RCM HYD-3 Groundwater Discharge Permit. If groundwater dewatering is required during construction of the proposed project, the City of Yorba Linda Public Works Department shall submit a Notice of Intent (NOI) for coverage under the permit to the Santa Ana RWQCB at least 60 days prior to the start of excavation activities and anticipated discharge of dewatered groundwater to surface waters in order to obtain coverage under the General Waste Discharge Requirements for Discharges to Surface Waters That Pose an Insignificant (De Minimis) Threat to Water Quality (Groundwater Discharge Permit), Order No. R8-2020-0006, NPDES No. CAG998001. The construction contractor shall comply with the requirements of Order No. R8-2020-0006, NPDES No. CAG998001. Groundwater dewatering activities shall comply with all applicable provisions in the Groundwater Discharge Permit, including water sampling, analysis, treatment (if required), and reporting of dewatering-related discharges. Upon completion of groundwater dewatering activities, a Notice of Termination shall be submitted to the Santa Ana RWQCB.

RCM HYD-4 MS4 Permit. Prior to construction, the Construction Contractor shall prepare a Final WQMP consistent with the requirements of the Model Water Quality Management Plan (WQMP) (County of Orange 2011), Technical Guidance Document for the Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans (WQMPs) (OC Public Works 2013), the City of Yorba Linda Local Implementation Plan (LIP) (2010), and Managing Wet Weather with Green Infrastructure Municipal Handbook Green Streets (EPA 2008), or subsequent guidance manuals. The Final WQMP shall specify the BMPs to be incorporated into the project design to target pollutants of concern in runoff from the project area. The BMPs specified in the Final WQMP shall be incorporated into the final project design, in accordance with the NPDES Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems (MS4s) Draining the Watersheds Within the Orange County Region, Order No. R8-2009-0030, NPDES No. CAS618030 as amended by Order No. R8-2010-0062 (MS4 Permit).

The City shall ensure the implementation of all feasible BMPs. The City shall

Page 389 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

Overall, because the proposed project would be required to comply with existing regulations including the Construction General Permit, the City of Yorba Linda Municipal Code, a Groundwater Discharge Permit, and the MS4 Permit, as specified in RCMs HYD-1 through HYD-4, the proposed project would not violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or groundwater quality. Impacts would be less than significant, and no mitigation is required.
(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?
Drought-tolerant planting per Landscaping Maintenance District (LMAD) guidelines will be used wherever new planting is added (e.g., in medians); areas to be restored will be replicated unless otherwise indicated by owner/City. Highly efficient drip irrigation will be used in new planting areas, as required; Planting areas to be restored will be replicated with matching irrigation equipment unless otherwise specified by owner/City.

An estimate of total annual water usage for newly planted areas (Model Water Efficient Landscape Ordinance [MWELO] calculations) will be provided once plans are nearly complete and will be designed to achieve the calculated Maximum Applied Water Allowance (MAWA) or less. All irrigation used within the proposed landscaped areas would be designed to follow Assembly Bill (AB) 1881 conservation requirements using water-efficient irrigation technologies, which would further reduce the proposed project’s operational water usage.

Less Than Significant Impact. The project limits fall within the boundaries of the Coastal Plain of Orange County Groundwater Basin (Coastal Plain Basin).
45 Recharge to the basin is derived from
percolation of Santa Ana River flow, infiltration of precipitation, and injection into wells.46 According to California’s Groundwater Bulletin 118, the storage capacity of the entire Coastal Plain Basin was calculated to be about 38,000,000 acre-feet, and the total amount of stored groundwater in 1998 was estimated to be approximately 37,700,000 acre-feet.
47 Construction. Construction of the proposed project would not generate a substantial demand for groundwater. As discussed in Response 4.10.(a) above, no groundwater was encountered in the exploratory borings to a depth of 41.5 feet bgs within the project limits. Ground-disturbing activities associated with construction of the proposed project would extend to a maximum depth of 32 feet bgs. Based on the depth of the groundwater and the depth of excavation activities, it is not anticipated that groundwater would be encountered during construction. In the event that groundwater 45 California Department of Water Resources (DWR). n.d. Groundwater Basin Boundary Assessment Tool.

Website: https://gis.water.ca.gov/app/bbat/ (accessed April 26, 2024). 46 California Department of Water Resources (DWR). 2004. Coastal Plain of Orange County Groundwater Basin. February. Website: https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Ground water-Management/Bulletin-118/Files/2003-Basin-Descriptions/8_001_CoastalPlainofOrangeCounty.pdf (accessed April 26, 2024). 47 Ibid.

Page 390 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-57
dewatering is required during excavation, it would be conducted in accordance with the Groundwater Discharge Permit, as specified in RCM HYD-3, which sets forth procedures to follow that would reduce potential impacts to a less than significant level. In addition, if groundwater dewatering is required during construction of the proposed project, dewatering activities would be temporary, and the volume of groundwater removed would not be substantial. Therefore, construction of the proposed project would not substantially decrease groundwater supplies such that the project may impede sustainable groundwater management of the basin.

In addition, construction of the proposed project would primarily impact existing impervious surfaces and would therefore not contribute to a substantial elimination of infiltration capacity within the project limits. Therefore, construction of the proposed project would not substantially interfere with groundwater recharge such that the project may impede sustainable groundwater management of the basin. Construction impacts associated with a substantial decrease in groundwater supplies or interference with groundwater recharge would be less than significant, and no mitigation is required.

Operation. The proposed project would improve an existing roadway and the only water usage would be minimal, associated with the irrigation of landscaped areas. As detailed in RCM HYD-2, the proposed project would be required to comply with all applicable and feasible BMPs set forth in the City’s Municipal Code, which includes compliance with the City’s LIP. Further, the proposed project would be required to comply with Chapter 16.12, Water Efficient Landscape Regulations, of the City’s Municipal Code. The proposed project would satisfy requirement (A)(2) under Section 16.12, Applicability, as it would consist of landscape rehabilitation and contains an aggregate landscaped area of 2,500 square feet or more. As such, the proposed project would be subject to the landscape water use standards set forth in Chapter 16.12, which would ensure that the proposed project would not involve inefficient use of groundwater supplies.

Under existing conditions, the project limits consist of a paved road and are predominantly comprised of impervious pavement. Therefore, the project limits are not considered a significant source of groundwater recharge. Development of the proposed project would result in a net increase of approximately 0.13 acre of impervious surfaces, which would result in a miniscule increase in impervious surface area. Therefore, operation of the proposed project would not interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin.

For the reasons listed above, and with implementation of RCM HYD-3 if construction dewatering is required, impacts related to the decrease of groundwater supplies or interference with groundwater recharge would be less than significant, and no mitigation is required. (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 off-site; Less Than Significant Impact. Under current conditions, the project limits are fully developed and consist of a six-lane divided roadway fitted with tiled and landscaped medians as well as curb areas containing landscaping and pedestrian sidewalks. According to the WQMP prepared for the proposed project, stormwater from the project limits drains from east to west from the beginning of the project

Page 391 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-58
limits to approximately 150 feet east of the Lakeview Avenue intersection. The project limits drain from west to east from approximately 150 feet east of Yorba Linda Boulevard/Lakeview Avenue intersection to the easterly end of the project limits. In general, both Imperial Highway and Lakeview Avenue tend to drain from north to south.

As previously stated, stormwater originating within the project limits would be potentially served by eight existing catch basin inlets. Stormwater draining to these inlets eventually dischargesto the Santa Ana River.

Construction. Construction activities associated with the proposed project would result in the total disturbance of 1.32 acres of soil. During grading and other construction activities, soil would be exposed and drainage patterns temporarily altered, and there would be an increased potential for soil erosion and siltation compared to existing conditions. Additionally, during a storm event, soil erosion and siltation could occur at an accelerated rate.

In compliance with RCM HYD-1, the proposed project would be subject to the requirements of the Construction General Permit, which requires the preparation of an SWPPP to identify construction BMPs to be implemented to reduce impacts on water quality during construction, including those impacts associated with soil erosion and siltation. In addition, construction of the proposed project must comply with City Municipal Code Chapter 16.04, as specified in RCM HYD-2, which requires the implementation of minimum construction BMPs including, but not limited to, minimizing the size and exposure time of disturbed soil areas, stabilizing all slopes, and utilizing sediment controls.

Compliance with RCM HYD-1 and RCM HYD-2, which require compliance with the Construction General Permit and implementation of construction BMPs, would ensure that construction impacts related to on- or off-site erosion or siltation would be less than significant.

Operation. After the completion of construction, the proposed project would not significantly alter the existing drainage pattern of the project limits. Operation of the proposed project would provide mobility improvements to existing roadway uses along Yorba Linda Boulevard, which would involve reconfigurations of existing pervious (i.e., landscaped areas) and impervious (i.e., roadway and median) surfaces. As part of the proposed improvements, Yorba Linda Boulevard would be widened, which would result in curb and median realignments. In order to accommodate this widening, the existing catch basin on the north side of Yorba Linda Boulevard west of Imperial Highway in front of the Mimi’s Café Restaurant would be shifted to align with the proposed curb position, which would not significantly alter the existing drainage pattern of the project limits. As previously stated, implementation of the proposed project would result in a net increase of 0.13 acre of impervious surface area, representing a minimal portion of the project limits’ total area of 4.42 acres. This change would be expected to result in a nominal net increase in stormwater runoff. Further, compliance with the City’s Municipal Code and MS4 Permit, as specified in RCM HYD-4, would require the proposed project to incorporate applicable BMPs pertaining to stormwater control and treatment to reduce the potential for erosion or siltation on- or off-site during project operation. BMPs identified in the City’s LIP that are relevant to the proposed project include but are not limited to disconnection of impervious surfaces through distributed pervious areas and landscaping with native or drought tolerant species. Through compliance with applicable regulations and incorporation of BMPs as required by RCM HYD-2 and RCM HYD-4, operational impacts related to on- or off-site erosion or siltation would be less than significant, and no mitigation is required.

Page 392 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-59
ii. Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or offsite;
Less Than Significant Impact.

Construction. The proposed project would comply with the requirements of the Construction General Permit, which requires the preparation of a SWPPP to identify construction BMPs to be implemented as part of the proposed project, pursuant to RCM HYD-1. In addition, the proposed project must comply with Section 16.04 of the City’s Municipal Code, which requires compliance with all applicable construction BMPs set forth in the Orange County DAMP and the City’s LIP, as specified in RCM HYD-2.

With adherence to RCM HYD-1 and RCM HYD-2, construction impacts related to a substantial increase in the rate or amount of surface runoff that would result in on- or off-site flooding would be less than significant, and no mitigation is required.

Operation. Operation of the proposed project would result in an increase in impervious surfaces within the project limits of approximately 0.13 acre, which could have the potential to increase the volume and rate of stormwater runoff discharged from the project limits. In the post-project condition, stormwater would continue to be directed to one of eight curb inlets along Yorba Linda Boulevard, Imperial Highway, and Lakeview Avenue,similar to existing conditions. As specified in RCM HYD-4, the proposed project is required to include a WQMP consistent with the MS4 Permit. The WQMP prepared for the proposed project explains why certain BMPs, such as infiltration type LID BMPs are infeasible, while explaining the BMPs that would be included as part of the proposed project, such as biofiltration devices.

In addition, as specified in RCM HYD-2, the proposed project would also be required to comply with all applicable BMPs set forth in the City’s Municipal Code, including those identified in the Orange County DAMP and the City of Yorba Linda Water Quality LIP. As such, applicable BMPs would be appropriately incorporated and sized to accommodate the rate and amount of stormwater runoff in the post-project condition to prevent on- or off-site flooding. With implementation of BMPs in compliance with the MS4 Permit as required by RCM HYD-2 and RCM HYD-4, operation of the proposed project would not substantially increase the rate or amount of surface runoff in a manner that would result in flooding on- or off site. Impacts would be less than significant, and no mitigation is required.
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 Less Than Significant Impact.

Stormwater Drainage System Capacity. Under existing conditions, stormwater from the project limits drains to one of eight curb inlets along Yorba Linda Boulevard, Imperial Highway, or Lakeview Avenue.

As a co-permittee of the Santa Ana RWQCB, the City of Yorba Linda is responsible for ensuring that existing infrastructure is capable of supporting new development within the City. With implementation of the proposed project, the existing catch basin on the north side of Yorba Linda Boulevard west of Imperial Highway in front of the Mimi’s Café Restaurant would be shifted to align with the proposed curb position. Stormwater would continue to be directed to one of the eight curb inlets within or just outside of the project limits, similar to existing conditions. As previously discussed, the project limits currently consist of a roadway developed with predominantly impervious surface

Page 393 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-60
area and the proposed project would not result in a substantial increase of surface runoff in comparison to existing conditions. Therefore, the proposed project would not create additional runoff in excess of the City’s existing stormwater drainage system.

Polluted Runoff. As discussed in Response 4.10(a), pollutants of concern during construction include sediments, trash, petroleum products, concrete waste (dry and wet), sanitary waste, and chemicals, and each of these pollutants on its own or in combination with other pollutants can have a detrimental effect on water quality. Drainage patterns would be temporarily altered during grading and other construction activities, and construction-related pollutants could be spilled, leaked, or transported via storm runoff into adjacent drainages and downstream receiving waters. However, as previously discussed, the proposed project would comply with the requirements set forth by the Construction General Permit, as specified in RCM HYD-1, including preparation of an SWPPP, which would identify appropriate and feasible BMPs to be implemented during construction to control the discharge of pollutants in stormwater runoff as a result of construction activities. In addition, the proposed project must comply with City Municipal Code Chapter 16.04, as specified in RCM HYD-2, which requires the adoption of all feasible and applicable BMPs presented in the Orange County DAMP and the City’s LIP, and would ensure the proposed project would not discharge substantial sources of polluted runoff from the project limits during construction activities.

Expected pollutants of concern from long-term project operations include suspended solids/ sediment, nutrients, oil and grease, metals, and trash and debris. As previously discussed, the proposed project’s compliance with the MS4 Permit, as specified in RCM HYD-4, which requires the implementation of applicable BMPs to target pollutants of concern during operations of the proposed project, would ensure that the proposed project would not discharge substantial sources of polluted runoff from the project limits during project operations.

According to the WQMP prepared for the proposed project, the right-of-way within the project limits is highly constrained. As a result, the utilization of infiltration type LID BMPs would be infeasible for the proposed project. However, in place of the infiltration type LID BMPs, proprietary biotreatment would be utilized. Specifically, two new Contech Filterra Biotreatment devices would be installed within the project limits to treat stormwater; one along Imperial Highway just north of Yorba Linda Boulevard and one along Yorba Linda Boulevard near the easternmost project limits. These devices use engineered filters and natural components such as mulch, organic material, and plants in order to treat potential pollutants and nutrients contained in stormwater as it percolates through the devices. Treated water would then infiltrate, evapotranspire, or be conveyed to the City’s stormwater conveyance system.

In addition, all non-structural source control BMPs would be incorporated into the proposed project, including:
• Right-of-Way Landscape Management
• BMP Maintenance
• Right-of-Way Litter Control
• Employee Training
• Right-of-Way Catch Basin Inspection
• Street Sweeping

Page 394 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-61
The proposed project would also incorporate structural source control BMPs, including storm drain stenciling/signage and the use of efficient irrigation systems and landscape design. With incorporation of these BMPs, the proposed project would not discharge substantial sources of polluted runoff from the project limits during operations.

With compliance with applicable regulations, including the Construction General Permit, City Municipal Code Chapter 16.04, and the MS4 Permit, as specified in RCM HYD-1, RCM HYD-2, and RCM HYD-4, impacts associated with creating or contributing runoff water, which would exceed the capacity of existing or planned stormwater drainage systems, or providing substantial additional sources of polluted runoff would be less than significant, and no mitigation is required. iv. Impede or redirect flood flows?
No Impact. According to the City’s General Plan Public Health and Safety Element, the Santa Ana River, which is located approximately 2.3 miles southeast of the project limits, is the City’s primary floodway.48 According to Exhibit PS-4, Flood Hazards, of the City’s Public Health and Safety Element, the project limits do not fall within the 100-year floodplain, although other portions of the City do.49 According to Figure PS-4 of the City’s Public Health and Safety Element, the nearest land to the project limits that falls within the 100-year floodplain is located approximately 0.10 mile south of the project limits. In addition, according to Exhibit PS-5, Dam Inundation Areas, of the City’s Public Health and Safety Element, the project limits do not fall within any dam inundation areas.

Further, according to the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) No. 06059C0064J (effective 12/3/2009),50 the project limits are located within Zone X, which is identified as an area of minimal flood hazard, with 0.2 percent annual chance of flood hazard.

Because the proposed project would not place improvements or structures directly within a 100-year floodplain, the proposed project would not impede or redirect flood flows. Therefore, no impact would occur related to impeding or redirecting of flood flows, and no mitigation is required. (d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? No Impact.

Flooding. As discussed above in Response 4.10(c), the project limits are not located within an area identified as susceptible to flood or dam inundation hazards by the City’s General Plan Public Health and Safety Element or FEMA FIRM No. 06059C0064J. The proposed project would not risk release of pollutants resulting from project inundation due to flooding.

Tsunami. Tsunamis are long wavelength, seismic sea waves (long compared to ocean depth) generated by the sudden movement of the ocean floor during submarine earthquakes, landslides, or volcanic activity. Seiches are waves generated in a large, enclosed body of water. The project limits 48 City of Yorba Linda. 2016. General Plan Public Health and Safety Element. October. Website: https://www. yorbalindaca.gov/DocumentCenter/View/473 (accessed April 29, 2024). 49 Ibid. 50 Federal Emergency Management Agency (FEMA). 2009. Flood Insurance Rate Map No. 06059C0068J. Map Revised December 3, 2009. Website: https://msc.fema.gov/portal/search?AddressQuery=18402%20Yorba %20Linda%20Blvd%2C%20Yorba%20Linda%2C%20CA%2092886 (accessed April 29, 2024).

Page 395 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-62
are located approximately 20 miles from the coast of the Pacific Ocean. As such, the project limits are not located within an area considered susceptible to tsunamis or seiche inundation. Therefore, the proposed project would not risk release of pollutants resulting from project inundation due to tsunami.

Seiches. Seiching is a phenomenon that occurs when seismic groundshaking induces standing waves (seiches) within enclosed or partially enclosed water bodies (e.g., reservoirs, lakes, bays). Such waves can cause flooding to adjacent properties. The nearest open body of water to the project limits is East Lake, located approximately 1.43 miles southeast of the project limits. Since no major lakes or open water impoundments exist within the vicinity of the project limits, the proposed project would not risk release of pollutants resulting from project inundation due to seiche.

Based on the geographic characteristics of the project limits, no impacts would occur related to inundation by flood, tsunami, or seiche, and no mitigation is required. (e) Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan?
The City of Yorba Linda is located within the jurisdiction of the Santa Ana RWQCB. The Santa Ana RWQCB has adopted a Water Quality Control Plan for the San Diego Basin (Basin Plan) for its region of responsibility that delineates water resource area boundaries based on hydrological features. For the purposes of achieving and maintaining water quality protection, specific beneficial uses have been identified for each of the surface waters and groundwater management zones described in the Basin Plan. Once beneficial uses are designated, appropriate water quality objectives can be established, and programs that maintain or enhance water quality can be implemented to ensure the protection of beneficial uses. As previously discussed, the proposed project would comply with existing NPDES permit requirements, including the Construction General Permit, Groundwater Discharge Permit, and MS4 Permit as specified in RCM HYD-1, RCM HYD-3, and RCM HYD-4, as well as City Municipal Code Chapter 16.04, including applicable BMPs, as specified in RCM HYD-2. Compliance with these existing regulations would require the implementation of construction and operational BMPs to manage onsite stormwater flows and reduce pollutants of concern in stormwater runoff. As such, the proposed project would not result in water quality impacts that would conflict with applicable water quality plans, and impacts would be less than significant.

The Sustainable Groundwater Management Act (SGMA) was enacted in September 2014. SGMA requires governments and water agencies of high- and medium-priority basins to halt overdraft of groundwater basins. Specifically, the SGMA requires the formation of local Groundwater Sustainability Agencies (GSAs), which are required to adopt Groundwater Sustainability Plans (GSPs), or an approved alternative to a GSP, to manage the sustainability of groundwater basins in California.

The project limits fall within the boundaries of the Coastal Plain Basin, which is identified by the Department of Water Resources (DWR) as a medium priority basin. 51 According to the DWR website,
basins ranked as medium- or high-priority are required to develop groundwater sustainability plans (GSPs) or submit an alternative to a GSP by the applicable statutory deadline. 51 California Department of Water Resources (DWR). 2020. Sustainable Groundwater Management Act 2019 Basin Prioritization. May.

Page 396 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-63
Because local agencies such as the Orange County Water District (OCWD) had already been sustainably managing the Coastal Plain Basin (also known as Basin 8-1) at the time the SGMA was enacted, an alternative plan was prepared rather than a GSP.52 This alternative, known as the Basin 8-1 Alternative, was prepared by OCWD, the City of Yorba Linda, and the Irvine Ranch Water District (IRWD) and was submitted to DWR on January 1, 2017. This document was updated on January 1, 2022, as part of a standard 5-year update. The Basin 8-1 Alternative, as updated,53 presents an analysis of basin conditions that demonstrated that Basin 8-1 had operated within its sustainable yield over a period of at least 10 years, in addition to the continued sustainable management over the 5 years since the original Basin 8-1 Alternative document. In addition, the Basin 8-1 Alternative (2022) describes current conditions, monitoring programs, water budgeting, sustainable management practices, and other information pertaining to the Coastal Plain Basin.

As discussed in Response 4.10(a), groundwater dewatering is unlikely to be required based on the exploratory borings conducted within the project limits. However, in the event that perched water is encountered and groundwater dewatering is necessary, adherence to RCM HYD-3 would ensure compliance with the Groundwater Discharge Permit, which would require testing and treatment (as necessary) of groundwater encountered during groundwater dewatering prior to release to surface waters to ensure that discharges do not exceed water quality limits specified in the permit. In addition, the proposed project would involve improvements to an existing roadway and would require minimal water service associated with irrigation of associated landscaping. As a result, the proposed project would allow for continued sustainable groundwater management and therefore would not create any conflicts with the Basin 8-1 Alternative (2022).

For the reasons above and with implementation of RCMs HYD-1 through HYD-4, impacts related to conflict with or obstruction of implementation of water quality control plans or sustainable groundwater management plans would be less than significant, and no mitigation is required. 52 Orange County Water District (OCWD). Draft Alternative to Groundwater Sustainability Plan Ready for Public Review. Website: https://www.ocwd.com/news-events/newsletter/2016/november-2016/draftalternative-to-groundwater-sustainability-plan-ready-for-public-review/ (accessed April 29, 2024). 53 Orange County Water District, City of La Habra, and Irvine Ranch Water District. 2022. Basin 8-1 Alternative 2022 Update. January. Website: https://www.ocwd.com/wp-content/uploads/05cbasin-8-1-alternative2022-update.pdf (accessed April 29, 2024).

Page 397 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-64

4.11 LAND USE AND PLANNING
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
(a) Physically divide an established community?
(b) Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? Impact Analysis
(a) Would the project physically divide an established community? Less Than Significant Impact. The physical division of an established community typically refers to the construction of a feature or removal of a means of access that would impair mobility within an existing community, or between a community and outlying areas.

In its existing condition, the project limits consist of approximately 0.28 mile of Yorba Linda Boulevard from its intersection with Imperial Highway to its intersection with Lakeview Avenue. According to the City of Yorba Linda’s General Plan Circulation Element, Yorba Linda Boulevard is classified as a Modified Major arterial roadway.54
Yorba Linda Boulevard generally runs in the east-west orientation, beginning in the City of Fullerton and traversing the City of Yorba Linda until it transitions into Weir Canyon Road near the City of Anaheim border. Major arterial roadways can be used for the movement of commercial goods and can carry regional through traffic, in this case between the cities of Fullerton, Placentia, Yorba Linda, and Anaheim. Therefore, under existing conditions, Yorba Linda Boulevard provides east-west connectivity and mobility within the City itself as well as between several cities in Orange County. The proposed improvements to Yorba Linda Boulevard would reduce congestion within the project limits, thus improving mobility within the region.

The project limits are located within a largely developed portion of the City of Yorba Linda consisting of commercial storefronts, residential neighborhoods, and urban landscaping. The proposed improvements to Yorba Linda Boulevard would affect an existing roadway and therefore would not introduce a new physical barrier that would divide an existing community because the general roadway alignment would remain intact. Therefore, the proposed project would have less than significant impacts associated with access and mobility within the existing community and between the community and outlying areas, and no mitigation is required. 54 City of Yorba Linda. 2016. General Plan Circulation Element. October. Website: https://www.yorbalindaca. gov/DocumentCenter/View/516/2016-GP-Circulation-Element?bidId= (accessed March 13, 2024).

Page 398 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-65
(b) Would the project cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect?
Less Than Significant Impact. The Southern California Association of Governments (SCAG), the regional planning agency for the six-county Southern California region that includes Los Angeles, Orange, Riverside, San Bernardino, Ventura, and Imperial Counties, is responsible for preparing a regional growth forecast in conjunction with its efforts to prepare a Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) for its regional planning area. In April 2024, SCAG adopted an updated RTP/SCS (Connect SoCal 2024), which integrates regional transportation and land use considerations. Connect SoCal 2024 includes visions, policies, and performance measures that align with SCAG’s vision for future growth within the Southern California region. As shown in Table 4.11.A, the proposed project would be consistent with applicable policies set forth by SCAG in Connect SoCal 2024.

Table 4.11.A: Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) Policy Consistency Analysis
Goals Consistency Analysis
Mobility Policy 01: Prioritize repair,
maintenance and preservation
of the SCAG region's existing
transportation assets, following a
"Fix-It-First" principle
Consistent. The proposed project would consist of modifications and improvements to an existing roadway in order to improve traffic operations rather than the development of a new roadway. Therefore, the proposed project is consistent with SCAG’s “Fix-It-First” principle, and would be consistent with Mobility Policy 01 of the RTP/SCS.

Source: Southern California Association of Governments. 2024. Connect SoCal Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS). April. Website: https://scag.ca.gov/sites/main/files/file-attachments/23-2987-connect-socal-2024-final-complete040424.pdf?1712261565 (accessed April 26, 2024). 1 City of Yorba Linda. 2016. General Plan Circulation Element. October. Website: https://www.yorbalindaca.gov/Document Center/ View/516/2016-GP-Circulation-Element?bidId= (accessed March 13, 2024).

The proposed project also would be required to comply with the City’s General Plan goals and policies addressing the circulation system, including the City’s roadways. The Circulation Element of the City of Yorba Linda General Plan guides the development of the City's circulation system in a manner that supports the citywide objectives of the General Plan. It addresses the circulation improvements needed to relieve traffic congestion due to future land uses, and establishes a hierarchy of transportation routes with specific development standards described for each category of roadway.

There are five categories in the hierarchy, including “Smart Street,” “Major,” “Primary,” “Secondary,” and “Collector” roadways.
55 This element also provides performance criteria for each category in the form of Level of Service (LOS). The City has established LOS D as the threshold or lowest acceptable level of roadway and intersection operation for planning purposes. As of 2016 when the Circulation Element was adopted, all roadway segments within the City operated at LOS C or better aside from three segments of Imperial Highway.

As stated in Response 4.11(a), Yorba Linda Boulevard is classified as a Modified Major arterial roadway in the City’s General Plan Circulation Element. According to the Circulation Element, the desired goal for every classified street section is that it carries the designed volume of traffic at LOS D or better.

According to Table CR-1 in the Circulation Element, the estimated daily capacity of Major (including 55 City of Yorba Linda. 2016. General Plan Circulation Element. October. Website: https://www.yorbalinda ca.gov/DocumentCenter/View/516/2016-GP-Circulation-Element?bidId= (accessed March 13, 2024).

Page 399 of 1177 ends

YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

F ROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OCTOBER 2024
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-66
Modified Major) arterial roadways within the City is 56,300 vehicles per day. According to the City’s website, the vehicle volume along Yorba Linda Boulevard ranges from approximately 24,000 to 36,000 vehicles per day.
56 Under the proposed improvements, no significant adverse effects would occur related to the City’s circulation system that would result in conflicts with transportation plans. Please refer to Section 4.17, Transportation, of this IS/MND, for a detailed description of the proposed project’s effects on the roadway’s circulation and intersections within the project limits.

Please refer to Table 4.11.B below for a breakdown of the proposed project’s consistency with applicable goals and policies of applicable elements of the City’s General Plan, including the Growth Management and Land Use Elements in addition to the Circulation Element. As shown in Table 4.11.B, the proposed project would return the Yorba Linda Boulevard roadway’s performance to Circulation Element targets and would be consistent with all other applicable General Plan policies pertaining to roadway mobility, land use, and growth management.

As stated in the Circulation Element, the proposed project would also be required to comply with the 2023 Orange County Congestion Management Program (CMP).57 The Orange County CMP was established in 1991 to reduce traffic congestion and assist in the coordination of land use decisions.

Compliance with the CMP is required in order for a city to be eligible for State gas tax funds for local transportation projects. According to Figure 2, Congestion Management Program Highway System, of the Orange County CMP, Imperial Highway is considered part of the CMP Highway System58. However, there are no specific CMP requirements for roadway segment monitoring.59 Further, Figure 5, Summary of Conformance, in the Orange County CMP states that no CMP intersections currently exist within the City. Based on this, and the fact that the proposed project would ultimately contribute to the achievement of traffic congestion reduction goals set forth in the CMP, the proposed project would be consistent with the Orange County CMP.

The proposed project would also partially intersect with the Yorba Linda Town Center (YLTC) Specific Plan, which was established by City Ordinance No. 2011-962 on July 7, 2011. The YLTC Specific Plan Area is bound by Yorba Linda Boulevard to the south and Imperial Highway to the west. Therefore, Yorba Linda Boulevard is directly adjacent to the southern edge of the YLTC Specific Plan Area, and provides access to the YLTC Specific Plan Area via a driveway that can be accessed from both directions of Yorba Linda Boulevard. This access would be maintained under the proposed project. 56 City of Yorba Linda. Yorba Linda Boulevard Corridor. Website: https://www.yorbalindaca.gov/179/YorbaLinda-Boulevard-Corridor (accessed March 13, 2024). 57 Orange County Transportation Authority (OCTA). 2023. 2023 Orange County Congestion Management Program Report. November. Website: https://www.octa.net/pdf/2023CMP.pdf?n=202311 (accessed March 13, 2024). 58 Ibid. 59 City of Yorba Linda. 2016. General Plan Circulation Element. October. Website: https://www.yorbalinda ca.gov/ DocumentCenter/View/516/2016-GP-Circulation-Element?bidId= (accessed March 13, 2024).

Page 400 of 1177 ends

I NITIAL S TUDY /MITIGATED NEGATIVE DECLARATION
OC TOBER 2024
YORBA L INDA BOULEVARD I MPROVEMENTS P ROJECT –

FROM I MPERIAL HIGHWAY TO L AKEVIEW AVENUE

YORBA L INDA, C ALIFORNIA
P:\20231457 - BKF Yorba Linda_Imperial Hwy\ISMND\Yorba Linda Improvements Imperial-Lakeview_Public Review Draft ISMND.docx (10/02/24)
4-67
Table 4.11.B: General Plan Policy Consistency Analysis
Policies Consistency Analysis
Circulation Element
Policy CR-1.4: Maintain a
Level of Service (LOS) “D” or
better along all City arterials
and at intersections during
peak hours.

Consistent. The proposed project would not adversely affect the level of service (LOS) of the project limits intersections, and would actually slightly improve traffic delays under current and future scenarios. Further, the proposed project would improve the existing traffic queuing issue and would ensure that queues do not exceed the storage capacities of the turn pockets in all but one turning scenario, which would improve the flow of traffic within the project limits. Therefore, the proposed project would be consistent with Policy CR-1.4 of the City of Yorba Linda’s General Plan Circulation Element.

Policy CR-1.6: Provide,
where feasible, increased
east-west traffic capacity
through the City.

Consistent. Yorba Linda Boulevard runs east-west across the City of Yorba Linda, beginning in the City of Fullerton and terminating near the border between the City of Yorba Linda and the City of Anaheim. The proposed project would generally improve the existing traffic queuing issues and would therefore improve traffic delays under current and future scenarios at the study intersections, which would improve east-west mobility along Yorba Linda Boulevard. Therefore, the proposed project would be consistent with Policy CR-1.6 of the City of Yorba Linda’s General Plan Circulation Element.

Policy CR-3.2: Provide for
safe and efficient traffic
operations, by maintaining
City standards for the
installation and operations
of traffic control devices.

Consistent. In addition to the proposed road widening, turn lane conversions, and restriping, the proposed project would also modify the existing traffic signals at the intersections of Yorba Linda Boulevard with Imperial Highway and Lakeview Avenue. These modifications would occur in order to adjust the intersections to the modified alignments and lane configurations that would result from the proposed improvements. Through these traffic signal modifications, the proposed project would enhance the safety of the intersections by ensuring the signals are as up-to-date as possible and reflect current intersection conditions.

Therefore, the proposed project would be consistent with Policy CR-3.2 of the City’s General Plan Circulation Element.

Policy CR-3.5: Effectively
operate and maintain
transportation facilities and
infrastructure to improve
system capacity and meet
traffic demand.

Consistent. As previously stated, the proposed project is intended to address the existing and future congestion and operation at the intersections of Yorba Linda Boulevard with Imperial Highway and Lakeview Avenue. The turn lane additions would expand the collective turn lane storage capacities to ensure that queues do not exceed the storage capacities of the turn pockets. As such, the proposed project would help the project limits meet current and future traffic needs. Therefore, the proposed project would be consistent with Policy CR-3.5 of the City’s General Plan Circulation Element.

Policy CR-4.1: Promote
landscaped medians and
greenbelts along major
arterials, highways, and
freeways on available rightof ways with droughttolerant plants where economically feasible.

Consistent. As previously stated, Yorba Linda Boulevard is considered a Modified Major Arterial roadway in the City’s General Plan Circulation Element. Although the proposed project would require vegetation removal in order to accommodate the proposed widening and other improvements, areas to be restored would be replicated with the previously present species. Areas of new landscaping would consist of drought tolerant trees, shrubs, perennials, and grasses pursuant to guidelines set forth by the Yorba Linda Street Lighting and Landscaping Maintenance District (also known as “LMAD”). Therefore, once the proposed project is operational, the project limits’ landscaped curb and median areas would contain aesthetically pleasing and drought tolerant plants. Therefore, the proposed project would be consistent with Policy CR-4.1 of the City’s General Plan Circulation Element.

Policy CR-4.2: Promote
maintenance of existing and
future landscaped rights-ofway and easements.

Consistent. The City’s Public Works Department would be responsible for the maintenance of the City’s public landscaped areas, including the curb and median landscaped areas within the project limits. Specifically, the responsible Public Works Department division would be LMAD. Proper maintenance of new planting areas would be ensured through the use of highly efficient drip irrigation that would be used in new planting areas. Planting areas to be restored would be replicated with matching irrigation equipment to the previous conditions unless otherwise specified. Therefore, the proposed project would be consistent with Policy CR-4.2 of the City’s General Plan Circulation Element.

Page 401 of 1177 ends

Yorba Linda City CouncilJanuary 21, 2025

Yorba Linda City Council
January 21, 2025