Public Review ISMND 1515 Walnut Grove Avenue Project
Public Review Draft Initial Study/
Mitigated Negative Declaration
1515 Walnut Grove Avenue Project
August 2026
Lead Agency:
City of Rosemead
8838 Valley Boulevard
Rosemead, CA 91770
(626) 569-2140
Consultant:
Kimley-Horn and Associates, Inc.
660 South Figueroa Street, Suite 2100
Los Angeles, CA 90017
Jessie Fan, Project Manager
(213) 344-2522
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Table of Contents
1.0 INTRODUCTION .........................................................................................................1
1.1 Statutory Authority and Requirements ......................................................................1
1.2 Summary of Findings..................................................................................................1
1.3 Initial Study Public Review Process ............................................................................2
1.4 Incorporation by Reference .......................................................................................2
1.5 Report Organization ...................................................................................................3
2.0 PROJECT DESCRIPTION ...............................................................................................4
2.1 Project Overview .......................................................................................................4
2.2 Location .....................................................................................................................4
2.3 Environmental Setting ...............................................................................................7
2.4 Project Characteristics ...............................................................................................8
2.5 Project Construction ................................................................................................17
2.6 Agreements, Permits, and Approvals .......................................................................18
2.7 Environmental Factors Potentially Affected .............................................................18
3.0 LEAD AGENCY DETERMINATION ..............................................................................19
4.0 EVALUATION OF ENVIRONMENTAL IMPACTS ...........................................................20
4.1 Aesthetics ................................................................................................................21
4.2 Agricultural and Forestry Resources .........................................................................26
4.3 Air Quality ................................................................................................................28
4.4 Biological Resources ................................................................................................39
4.5 Cultural Resources ...................................................................................................44
4.6 Energy .....................................................................................................................48
4.7 Geology and Soils .....................................................................................................56
4.8 Greenhouse Gas Emissions ......................................................................................64
4.9 Hazards and Hazardous Materials ............................................................................72
4.10 Hydrology and Water Quality ...................................................................................79
4.11 Land Use and Planning .............................................................................................85
4.12 Mineral Resources ...................................................................................................89
4.13 Noise .......................................................................................................................90
4.14 Population and Housing ......................................................................................... 111
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4.15 Public Services ....................................................................................................... 113
4.16 Recreation ............................................................................................................. 117
4.17 Transportation ....................................................................................................... 118
4.18 Tribal Cultural Resources ....................................................................................... 121
4.19 Utilities and Service Systems .................................................................................. 126
4.20 Wildfire .................................................................................................................. 132
4.21 Mandatory Findings of Significance ........................................................................ 134
Appendices
Appendix A: Air Quality Analysis Technical Memorandum
Appendix B: Archaeological Resources Assessment
Appendix C: Energy Calculations
Appendix D-1: Geotechnical Investigation Report
Appendix D-2: Fault Rupture Hazard Assessment
Appendix E: Paleontological Resources Assessment
Appendix F: Greenhouse Gas Emissions Assessment Technical Memorandum
Appendix G: Phase I Environmental Site Assessment
Appendix H: Phase II Environmental Site Assessment
Appendix I: Hydrology & Hydraulics Report
Appendix J: Preliminary Low Impact Development Report
Appendix K: Noise and Vibration Analysis Technical Memorandum
Appendix L: Traffic Study
Appendix M: Vehicle Miles Traveled Analysis
Appendix N: Water Service Availability Letter
Appendix O: Sanitary Sewer Capacity Study
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List of Figures
Figure 2.2-1: Regional Vicinity Map .............................................................................................5
Figure 2.2-2: Aerial of Project Site and Surrounding Land Use Map .............................................6
Figure 2.4-1: Site Plan................................................................................................................10
Figure 2.4-2: Row Townhomes Front and Rear Elevations .........................................................11
Figure 2.4-3: Tandem Townhomes Front and Rear Elevations ...................................................12
Figure 2.4-4: Entry Gate and Monument Sign Elevations ...........................................................14
Figure 2.4-5: Conceptual Landscape Master Plan ......................................................................15
Figure 4.13-1: Noise Monitoring Location Map..........................................................................93
Figure 4.13-2: Sensitive Receptor Locations Map ......................................................................95
List of Tables
Table 2.3-1: On-Site and Surrounding Land Uses .........................................................................8
Table 2.4-1: Project Development Summary ...............................................................................9
Table 4.3-1: South Coast Air Quality Management District Significance Threshold ....................28
Table 4.3-2: Local Significance Thresholds for Construction and Operations .............................29
Table 4.3-3: Project Construction Emissions ..............................................................................33
Table 4.3-4: Project Operational Emissions ...............................................................................34
Table 4.3-5: Equipment Specific Grading Rates..........................................................................35
Table 4.3-6: Localized Significance of Project Construction Emissions .......................................35
Table 4.3-7: Localized Significance of Operational Emissions .....................................................36
Table 4.4-1: Endangered and/or Threatened Species in the Vicinity of the Project Site .............40
Table 4.6-1: Project Construction Energy Consumption .............................................................51
Table 4.6-2: Annual Project Operational Energy Consumption ..................................................52
Table 4.8-1: Construction Greenhouse Gas Emissions ...............................................................65
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Table 4.8-2: Project Operational Greenhouse Gas Emissions .....................................................66
Table 4.8-3: 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy
Consistency ...............................................................................................................................69
Table 4.13-1: City of Rosemead Noise Standards .......................................................................91
Table 4.13-2: Existing Noise Measurements ..............................................................................94
Table 4.13-3: Sensitive Receptors ..............................................................................................94
Table 4.13-4: Typical Construction Noise Levels ........................................................................97
Table 4.13-5: Project Maximum Construction Noise Levels .......................................................98
Table 4.13-6: Mechanical Equipment Noise Levels .................................................................. 100
Table 4.13-7: Dog Park Noise Levels ........................................................................................ 102
Table 4.13-8: Composite Noise Levels ..................................................................................... 104
Table 4.13-9: Typical Construction Equipment Vibration Levels ............................................... 107
Table 4.13-10: Mitigated Construction Equipment Vibration Levels ........................................ 107
Table 4.19-1: Estimated Water Demand .................................................................................. 127
Table 4.19-2: Estimated Wastewater Generation .................................................................... 128
Table 4.19-3: Estimated Solid Waste Generation ..................................................................... 130
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1.0 INTRODUCTION
1.1 Statutory Authority and Requirements
1515 Walnut Grove, LP (Applicant) proposes to demolish the existing four-story office building
and detached central plant building located at 1515 Walnut Grove Avenue, and construct a new
residential community composed of tandem townhomes and row townhomes, parking, and open
space, amenities, landscaping (Project).
The City of Rosemead (“City”), as Lead Agency, determined that the Project is subject to the
California Environmental Quality Act (“CEQA”), and that preparation of an initial study is required.
This Initial Study (“IS”) evaluates the potential environmental effects that could result from the
construction and operation of the Project. This IS has been prepared in accordance with California
Public Resources Code (“PRC”) Section 21000 et seq. (CEQA) and Title 14 of the California Code
of Regulations (“CCR”) Section 15000, et. seq. (“CEQA Guidelines”).
Based on the analysis provided within this IS, the City concluded that, with incorporation of the
identified mitigation as agreed to by the Applicant, the Project would not result in significant
impacts on the environment and, therefore, that the preparation of a mitigated negative
declaration (“MND”) is intended as an informational document and is ultimately required to be
adopted by the City’s decision-making body before or concurrently with the Project.
1.2 Summary of Findings
Pursuant to CEQA Guidelines Section 15367, the City, as Lead Agency, has the authority for
environmental review and adoption of the environmental documentation, in accordance with
CEQA. This IS and MND evaluated the environmental issues outlined in Section 2.7:
Environmental Factors Potentially Affected. It provides decision-makers and the public with
information concerning the proposed Project’s potential environmental effects and
recommended mitigation measures, if any.
Based on this IS and MND, and supporting environmental analysis, the proposed project would
have no impact or a less than significant impact concerning all environmental issue areas, except
the following, for which the proposed project would have a less than significant impact with
mitigation incorporated:
• Biological Resources
• Cultural Resources
• Geology and Soils
• Hazards and Hazardous Materials
• Noise
• Tribal Cultural Resources
As set forth in CEQA Guidelines Section 15070, a mitigated negative declaration can be prepared
when the initial study identifies potentially significant effects, but project revisions would avoid
or mitigate the effects to a point where clearly no significant effects would occur, and there is no
substantial evidence, in light of the whole record before the agency, that the project as revised
may have a significant effect on the environment.
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1.3 Initial Study Public Review Process
In accordance with CEQA Guidelines Section 15072, a Notice of Intent to Adopt a Mitigated
Negative Declaration (“NOI”) was provided to the Clerk of the County of Los Angeles and mailed
to responsible and trustee agencies concerned with the proposed project and other public
agencies with jurisdiction by law over resources affected by the project. A 20-day public review
period has been established for the IS/MND in accordance with CEQA Guidelines Section 15073.
During the public review period, the IS/MND, including the Technical Appendices, was made
available for review on the City website, at
https://rosemeadca.gov/services/city_clerk/public_notices.phps.
In reviewing the IS/MND, affected public agencies and the interested public should focus on the
document’s adequacy in identifying and analyzing the potential environmental impacts and the
ways in which the Project’s potentially significant effects can be avoided or mitigated.
Written comments on this IS/MND may be sent to:
City of Rosemead
8838 Valley Boulevard
Rosemead, CA 91770
Email: alao@rosemeadca.gov
Following receipt and evaluation of comments from agencies, organizations, and/or individuals,
the City will determine whether any substantial new environmental issues have been raised. If
so, further documentation may be required. If not or if the issues raised do not provide
substantial evidence that the Project would have a significant effect on the environment, the
IS/MND will be considered for adoption and the Project for approval.
1.4 Incorporation by Reference
Pursuant to CEQA Guidelines Section 15150, a mitigated negative declaration may incorporate
by reference all, or portions of, another document which is a matter of public record or is
generally available to the public. Where all or part of another document is incorporated by
reference, the incorporated language is considered set forth in full as part of the mitigated
negative declaration’s text.
The references outlined below, which were utilized during preparation of the IS/MND, are listed
below:
City of Rosemead General Plan and Zoning Code. The City adopted its comprehensive General
Plan (“General Plan”) on April 13, 2010. Since that adoption the following amendments have
occurred:
• On February 13, 2018, the Land Use and Circulation Elements of the General Plan were
amended.
• On July 23, 2021, the Land Use Element was amended to include the Freeway Corridor
Mixed-Use Overlay (FCMU).
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• On January 11, 2022, the Public Safety Element was amended in compliance with recent
state legislation related to safety elements, including Senate Bill (SB) 379 which requires
general plan safety elements to be revised and updated to include climate adaptation and
resiliency strategies at the time of the next general plan revision. In addition,
environmental justice policies were added to the General Plan and are located within the
Public Safety Element update.
• The Housing Element (2021-2029 Housing Element) was updated by the City on January
11, 2022, and certified by the California Department of Housing and Community
Development (HCD) on August 1, 2022.
1.5 Report Organization
This document is organized into the following sections:
Section 1.0: Introduction provides a project introduction and overview, cites pertinent CEQA
Guidelines, and summarizes the IS/MND’s conclusions.
Section 2.0: Project Description details the Project’s location, environmental setting,
characteristics, construction activities, and required permits and approvals. This section also
identifies the IS/MND’s intended uses, including a list of anticipated permits and other approvals.
Section 3.0: Lead Agency Determination provides the determination regarding the potential
environmental effects of the Project and an overview of potential impacts that may or may not
result from Project implementation.
Section 4.0: Evaluation of Environmental Impacts provides an analysis of environmental impacts
identified in the environmental checklist.
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2.0 PROJECT DESCRIPTION
2.1 Project Overview
The Applicant proposes to demolish the existing four-story office building and detached central
plant building located at 1515 Walnut Grove Avenue, in the City of Rosemead (City) and construct
a new residential community composed of tandem townhomes and row townhomes, parking,
and open space, amenities, landscaping. The Project would also include right of way
improvements such as minor street frontage, sidewalk, and cross gutter improvements. The
proposed residential development would be comprised of 191 units in 27 buildings (Project) on
approximately 9.28 acres or 404,146 square feet (sf) (Project Site). The Project would develop a
total of 238,616 sf of floor area (excluding garages) over 404,146 sf of combined buildable area,
which constitutes an average floor area ratio (FAR) of 0.59:1. As the existing buildings on the
Project Site total 268,015 sf (see Section 2.3.1: On-Site Conditions for more details), the Project
would result in a net decrease of floor area on the Project Site (approximately 29,399 sf less than
existing).
2.2 Location
The Project Site is comprised of one parcel (Los Angeles County Assessor’s Parcel Number [APN]
5279-027-001). The Project Site is surrounded by office development, commercial uses, and
surface parking to the north; Walnut Grove Avenue and the Whittier Narrows Golf Course to the
east; surface parking and the University of the West, including the Institute of Chinese Buddhist
Studies, to the south; and residential development to the west. Unincorporated areas of Los
Angeles County border the Project Site to the east of Walnut Grove Avenue and to the west along
the Project Site’s western boundary.
Please refer to Figure 2.2-1: Regional Vicinity Map and Figure 2.2-2: Aerial of Project Site and
Surrounding Land Use Map.
Regional vehicle access to the Project Site is provided by the State Route (SR) 60 and SR 164
(Rosemead Boulevard), located approximately 0.54 miles (2,894 feet) south and 1.04 miles (5,491
feet) east, respectively. Local vehicle access to the Project Site is provided via Rush Street, located
approximately 0.20 miles (1,040 feet) north of the Project Site and Walnut Grove Avenue directly
east of the Project Site. The Project Site is located in proximity to several transit options. The
Project Site located approximately 0.25 miles (1,342 feet) south of the Los Angeles County
Metropolitan Transportation Authority (Metro) 287 bus stop at the northwest corner of the
intersection of Rush Street and Walnut Grove Avenue. The Project Site is also served by the
Montebello Transit 20 San Gabriel bus line, with a bus stop located approximately 0.33 miles
(1,772 feet) to the south of the site at the northwest corner of the intersection of San Gabriel
Boulevard and Walnut Grove Avenue.
6
6
Walmart
Panda Restaurant Group
Institute of Chinese
Buddhist Studies
University of the West
Whittier Narrows Golf Course
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2.3 Environmental Setting
2.3.1 On-Site Conditions
The Project Site is currently developed with two vacant buildings built in 1982 that were operated
by Southern California Edison (SCE). The Project Site includes a 249,701-sf office building; an
18,314-sf detached central plant building containing a chiller room, emergency generator room,
break room, office, restroom, fan room, boiler room, transformer room, and cooling towers; and
a surface parking lot with approximately 717 parking spaces on-site.1 A sewer lift station is also
located in the parking lot southwest of the office building. The office building and central plant
are currently vacant; however, the cooling systems within the central plant remain functional,
but not operational. There is minimal landscaping on the Project Site, limited to ornamental trees
and shrubs. Trees on-site include 36 Crepe Myrtles, 18 Tristania trees, 8 Liquidambar, 4
Jacaranda, 3 Ash, and 9 Magnolia trees. No oaks or protected trees exist on the Project Site.
2.3.2 General Plan and Zoning
The Project Site has a General Plan land use designation of Office/Light Industrial. The primary
uses allowed within the General Plan land use designation include commercial development and
light industrial uses. The Project proposes a General Plan Amendment to change the existing land
use designation from Office/Light Industrial to High Density Residential. The High Density
Residential land use category allows many forms of attached housing: triplexes, fourplexes,
apartments, and condominiums/townhouses, and small lot or clustered detached units. The
maximum permitted density is 30 units per acre.2
The Project Site is located within the Medium Commercial (C-3) Zone with a Design Overlay (D-
O). The Project proposes a Zoning Amendment to change the existing zone from C-3 and D-O to
Planned Development (P-D). According to the Rosemead Municipal Code (RMC), the P-D Zone
allows all land use designations in the RMC, except for high intensity commercial, open space,
and cemeteries.3 The P-D Zone is intended to provide for residential, commercial, industrial, or
institutional developments that are characterized by innovative use and design concepts. The P-
D Zone provides for new development to offer amenities, quality, design excellence, and other
similar benefits to the community.4
1 Based on the as-builts provided by SCE dated July 12, 2010, when the existing office building was occupied, the number of
employees working on site was approximately 904, and additional off-site parking spaces were utilized with shuttles provided
for employees.
2 City of Rosemead, 2021-2029 Housing Element, 2022, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/Adopted%20Rosemead%202021-2029%20Housing%20Element_CERTIFIED%20080122.pdf.
Accessed August 6, 2025.
3 City of Rosemead, Rosemead Municipal Code Title 17 Zoning, Article 2 Zoning Districts, Allowable Land Use and Zone Specific
Standards,
https://library.municode.com/ca/rosemead/codes/code_of_ordinances?nodeId=CD_ORD_TIT17ZO_ART2ZODIALLAUSZOECS
T. Accessed August 6, 2025.
4 City of Rosemead, Rosemead Municipal Code Title 17 Zoning, Chapter 17.24 Special Purpose Zoning Districts.
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2.3.3 Surrounding Land Uses
On-site and surrounding land uses and zoning designations are summarized in Table 2.3-1: On-
Site and Surrounding Land Uses and depicted on Figure 2.2-2.
Table 2.3-1: On-Site and Surrounding Land Uses
Description Existing On-the-Ground1 Existing Zoning2
Project Site Commercial office building, parking lot Medium Commercial (C-3) and
Design Overlay (D-O)
North Commercial office building, parking lot Medium Commercial (C-3)
South
University of the West (including the Institute of Chinese
Buddhist Studies), university research library, dining hall,
surface parking lot
Planned Development (P-D)
East Walnut Grove Avenue, Whittier Narrows Golf Course,
Unincorporated Los Angeles County Open Space (O-S)3
West Single-family residential development; Unincorporated Los
Angeles County Residential Agriculture (R-A)3
1. Google Earth Pro, 2025.
2. City of Rosemead, Zoning Map, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/P
lanning/Zoning%20Map%202021-11-17%20updated.pdf. Accessed August 6, 2025.
3. LA County Planning, Find Your Zoning, https://experience.arcgis.com/experience/0eecc2d2d0b944a787f282420c8b290c.
Accessed August 20, 2025.
2.4 Project Characteristics
As shown in Table 2.4-1: Project Development Summary, the Project would demolish the
existing structures and construct 27 buildings, including tandem townhomes (39 feet and 4 inches
tall) and row townhomes (38 feet tall). Of the 27 buildings, 13 buildings would be dedicated to
83 tandem townhomes and 14 buildings would be dedicated to 108 row townhomes. Each unit
would include two garage spaces. Per RMC Chapter 17.112, Table 17.112.040.1, the Project
would be required to provide 96 guest parking spaces. The Project would provide 104 double-
striped guest parking spaces, as described in RMC Chapter 17.112.111(H). Additionally, the
Project would provide public right of way improvements such as 1,253 sf of parkway, 3,000 sf of
City sidewalk improvements, and additional roadway repair (grind and remove existing asphalt
and replace with overlay of new asphalt) of Walnut Grove Avenue.
Figure 2.4-1: Site Plan, Figure 2.4-2: Row Townhomes Front and Rear Elevations, and Figure
2.4-3: Tandem Townhomes Front and Rear Elevations depict the proposed floor plan and
proposed elevations.
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Table 2.4-1: Project Development Summary
Project Component Conceptual Proposed Development
(Approximate Square Footage)
Floor Area 404,146 sf
Height Tandem townhomes: 39.4 feet
Row townhomes: 38 feet
Residential
Total Dwelling Units 191 units
Row Townhomes 108 units
Tandem Townhomes 83 Units
Parking Spaces
Resident Parking (Within Garages) 382 spaces
Guest Parking 104 spaces
Open Space
Landscape 70,382 sf
Hardscape 49,442 sf
Other Amenities (Playground, Pool Spa) 6,896 sf
Total Open Space and Amenities 126,720 sf
Right of Way Improvements
Parkway 1,253 sf
City sidewalk 3,000 sf
Source: Architerra Design Group, April 3, 2025.
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2.4.2 Architectural Design
The row townhomes would be inspired by Spanish architecture. The townhomes would include
concrete ‘S’ roof tile, decorative ceramic Spanish tile, arched balconies and porches, vertical
sliding panel entry doors and windows, and stucco trimmed windows and doors. The exterior
stucco design is linear with color accents. The row townhomes would have vertical iron railings.
The row townhomes would have squared wood posts that would provide balconies at the front
of the building. The rear of the building would provide access to five parking garages. A neutral
color palette would be incorporated into the Project design.
The tandem townhomes would be inspired by Prairie architecture. The tandem townhomes
would include a low pitch roof with concrete roof tile, a stucco finish, and iron horizontal railings.
The tandem townhomes would be framed with square metal posts. The entry door would have
a framed glass panel, and the windows would have a smooth trim finish panel. The front of the
tandem townhomes would have balconies. The rear of the buildings would provide access to the
parking garages. The tandem townhomes would have a darker color palette incorporated into
the Project design.
Two distinctive gateway monument signs and a visitor dial up kiosk would be located at each of
the vehicle and pedestrian entrance driveways for the Project Site along Walnut Grove Avenue.
The gateway monument signs and visitor dial up kiosk would be 5 feet tall and 9 feet long and
would include stone veneer pilaster and steel fencing. (see Figure 2.4-4: Entry Gate and
Monument Sign Elevations).
2.4.5 Open Space and Landscaping
The Project would provide approximately 126,720 sf of open space for residents, including
landscaping, hardscape, playground, pool, and a spa. A dog park, bench seating, and picnic tables
would be located in the northeast corner of the Project Site.
On the southeast corner of the Project Site, the Project would include a bioretention basin and
recreation center with a restroom facility, community pool, group spa, cabanas, gas barbeque
grills, and a sundeck. A community garden with dwarf citrus trees would be located in the
southwest corner of the Project Site. A central garden court with a shade structure, picnic tables,
open lawn play area, and tot-lot with play equipment and rubber surfacing would be located
between buildings 13, 14, 17, and 18, see Figure 2.4-5: Conceptual Landscape Master Plan.
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The Project would plant 282 new trees throughout the Project Site. These trees would include
Wilson’s Fruitless Olive, California Sycamore, Cajeput Tree, Chinese Pistache, Crepe Myrtle,
Strawberry Tree, Brisbane Box, After Dark Peppermint Willow, Southern Magnolia, Pink Trumpet
Tree, Forest Pansy, Fern Pine, Tiny Tower Italian Cypress, Date Park, and Southern Magnolia. The
Magnolia street trees on Walnut Grove Avenue would remain.
In addition to the proposed trees, the Project would plant a variety of drought tolerant and native
shrubs in the common open space areas and surrounding the Project Site, including the frontage
along Walnut Grove Avenue, and on the western side of the Project Site in the community
garden. The proposed trees and other landscaping along the exterior and within the interior of
the Project Site would help to create a visually attractive development and would enhance the
pedestrian environment.
The Project would include landscaping on the northern, eastern, southern, and western ends of
the Project Site and throughout the townhomes. A landscape buffer would be provided along the
Project perimeter. Proposed landscaping would include native trees, shrubs, and groundcover,
all of which would have very low or low water needs. Proposed landscaping would comply with
the City’s Water Efficient Landscape Ordinance.
2.4.3 Access, Circulation, and Parking
The Project Site would be gated, with resident and vehicle access provided from separate vehicle
and pedestrian entryways along Walnut Grove Avenue. Both the northern and southern
entryways would provide a two-way gated vehicle ingress and egress to the Project Site and
internal roadway system.
On either side of the vehicle gates would be separate pedestrian gates and pathways to the
Project Site. The Project entryways would feature distinctive Project monument signs, visitor dial
up kiosks, and enhanced vehicular pavement treatments. Internal walkways and enhanced
crosswalks would provide pedestrian access to various amenities within the Project Site. The
pedestrian gates would be accessible with a fob key.
The Project would include two parking spaces in the garage of each unit, resulting in 382 garage
spaces. The garages will be constructed with electric vehicle (EV) capability/readiness.
Additionally, the Project would include 104 guest parking spaces as surface parking, with 5 spaces
dedicated to American with Disabilities Act (ADA) compliant residential automobile spaces.
2.4.5 Lighting and Signage
The Project would install various exterior lights, including bollard lights and pole lights with
shielded down lighting around the building including interior and exterior lighting for security,
entrances, signage, wayfinding, architectural highlighting, and landscape/security lowlighting.
Outdoor lighting would be designed and installed with shielding to ensure that the lighting would
be focused on the Project Site and deflected away from adjacent residential properties. The
Project entryways and monument signs would be lit for access, safety, and visibility.
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2.4.4 Site Security
During construction, the Project Site would be secured with perimeter fencing. Upon buildout,
the Project Site would be gated and would offer distinctive pathways for pedestrians and
vehicles, both of which would have controlled access along Walnut Grove Avenue. Vehicle and
pedestrian access for residents would be provided via key fobs and electronic vehicle
transponders.
Visitors would be required to use a visitor dial-up kiosk to access the Project Site. Residential
entries, lobbies, and walkways would be differentiated for security, and illuminated for safety.
2.5 Project Construction
Project construction is anticipated to occur over one phase, lasting approximately 34 months,
beginning as early as October 2026 and ending as early as August 2029. This estimated
construction schedule represents a conservative analysis scenario should construction occur any
time after the respective dates since emission factors for construction decrease as time passes
and the analysis year increases due to emission regulations becoming more stringent.5 Project
construction and architectural coating would occur over one phase. Construction would be
consistent with the RMC Chapter 8.36, including, without limitation, the City’s noise policies.
Specifically, construction would be prohibited between the hours of 8 p.m. and 7 a.m. Monday
through Saturday and prohibited on Sunday or any Federal holiday, in accordance with RMC
Chapter 8.36.030, Exemptions. No nighttime construction activities are anticipated. Project
construction is anticipated to occur in the following sequence:
• Demolition,
• Site preparation,
• Grading, excavation, and foundations,
• Paving,
• Building construction,
• Infrastructure improvements, and
• Architectural coating.
Project Site preparation for the Project would require cutting of approximately 22,457 tons of
recycled concrete and 5,461 tons of recycled asphalt. The recycled concrete and asphalt materials
would remain on site to be reused and would not be hauled away. Approximately 7,500 cubic
yards of import would be required.
5 As shown in the CalEEMod User’s Guide Version 2022.1, Appendix C: Emission Calculation Details for CalEEMod, Section 4.3
“Off-Road Equipment Emission Factors Screen” as the analysis year increases, emission factors for the same equipment pieces
decrease due to the natural turnover of older equipment being replaced by newer less polluting equipment and new regulatory
requirements.
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2.6 Agreements, Permits, and Approvals
The City has discretionary authority over the proposed Project. Other agencies, in addition to the
City, are expected to use this IS/MND in their decision-making process. To implement this Project,
several discretionary permits are required from the City including, without limitation, at a
minimum, the following discretionary permits/approvals:
• Adoption of the Initial Study/Mitigated Negative Declaration
• General Plan Amendment
• Zone Change
• Planned Development
• Tentative Tract Map
2.7 Environmental Factors Potentially Affected
The environmental factors checked below would be potentially affected by the Project, involving
at least one impact that is a "Potentially Significant Impact" or “Less Than Significant With
Mitigation Incorporated,” as indicated by the checklist on the following pages.
Aesthetics Agricultural and Forestry
Resources Air Quality
X Biological Resources X Cultural Resources Energy
X Geology & Soils Greenhouse Gas
Emissions X Hazards & Hazardous
Materials
Hydrology & Water Quality Land Use & Planning Mineral Resources
X Noise Population & Housing Public Services
Recreation Transportation X Tribal Cultural Resources
Utilities & Service Systems Wildfire X Mandatory Findings of
Significance
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3.0 LEAD AGENCY 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.
X
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 or a 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 EIR or NEGATIVE DECLARATION pursuant to applicable
standards, and (b) have been avoided or mitigated pursuant to that earlier EIR or
NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed
upon the proposed Project, nothing further is required.
CITY OF ROSEMEAD
____________________________ _______________________________
Annie Lao Date
Senior Planner
8/19/26XY—__-____
Kimley»Horn
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4.0 EVALUATION OF ENVIRONMENTAL IMPACTS
The following environmental analysis is patterned after CEQA Guidelines Appendix G. An
explanation is provided for all responses except “No Impact” responses, which are supported by
the cited information sources. The responses consider the whole action involved with the
proposed Project: on- and off-site, Project- and cumulative-level, direct and indirect, and short-
term construction and long-term operational. The explanation of each issue also identifies the
significance criteria or threshold, if any, used to evaluate each question, and the mitigation
identified, if any, to avoid or reduce the impact to less than significant. To each question, there
are four possible responses:
• No Impact. The Project would not have any measurable environmental impact.
• Less Than Significant Impact. The Project would have the potential to impact the
environment, although this impact would be below established thresholds that are
considered to be significant.
• Less Than Significant with Mitigation Incorporated. The Project would have the
potential to generate impacts, which may be considered as a significant effect on the
environment, although mitigation measures or changes to the Project’s physical or
operational characteristics would reduce these impacts to a less than significant level.
• Potentially Significant Impact. The Project could have impacts, which may be
considered significant, and therefore additional analysis is required to identify
mitigation. A determination that there is a potential for significant effects indicates
the need to more fully analyze the Project’s impacts and identify mitigation.
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4.1 Aesthetics
Environmental Issue
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? X
b) Substantially damage scenic resources, including,
but not limited to trees, rock outcroppings, and
historic buildings within a State Scenic Highway?
X
c) If in a non-urbanized area, 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?
X
d) Create a new source of substantial light or glare
which would adversely affect day or nighttime
views in the area?
X
Impact Analysis
4.1a Would the project have a substantial adverse effect on a scenic vista?
Less Than Significant Impact. For purposes of determining significance under CEQA, a scenic vista
is generally considered a viewpoint that provides expansive views of a highly valued landscape
for the public’s benefit. The primary scenic vistas in Rosemead are of the San Gabriel Mountains
to the north, as well as the Whittier Narrows Golf Course and the La Puente Hills to the south.6
The Project Site is currently developed with two vacant buildings built in 1982 that were operated
by SCE. The Project Site includes a 249,701-sf office building; an 18,314-sf detached central plant
building containing a chiller room, emergency generator room, break room, office, restroom, fan
room, boiler room, transformer room, and cooling towers; and a surface parking lot. The office
building and central plant are currently vacant; however, the cooling systems within the central
plant remain functional, but not operational. There is minimal landscaping on the Project Site;
limited to ornamental trees and shrubs. The existing Project Site does is not considered scenic,
nor does it contain any valued views.
Existing scenic views visible from public streets near the Project Site are primarily visible from
Walnut Grove Avenue, which is a north/south corridor which affords views of the San Gabriel
Mountains to the north and expansive views of the Whittier Narrows Golf Course to the east. The
6 City of Rosemead, Addendum to the Rosemead General Plan Update Final Environmental Impact Report, 2021-2029 Housing
Element and Public Safety Element Update, January 11, 2022, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/HE%20PSE%20Update%20_Final%20Addendum_01112022.pdf. Accessed September 21, 2025.
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Whittier Narrows Golf Course includes one 18-hole regulation course and one 9-hole regulation
course among mature, undulating tree-lined fairways, and provides a green, picturesque
parkland area.7 Due to sloping topography of the Project Site and its vicinity, views of the La
Puente Hills to the south are not visible from Walnut Grove Avenue. Existing intervening
development and topography presently blocks views of the Whittier Narrows Golf Course from
streets located west of the Project Site.
The Project’s proposed tandem townhomes would be 30 feet and 4 inches tall, while the row
townhomes would be 38 feet tall. The existing office building is approximately 62 feet and 3
inches tall to the roof and helipad. Upon Project buildout, because the proposed tandem
townhomes would be shorter than the existing office building, views of the San Gabriel
Mountains to the north and Whittier Narrows Golf Course to the east would be more visible and
would continue to be visible from Walnut Grove Avenue and would remain as a scenic resource.
The Project would not directly obstruct an existing public view of a scenic vista and would not
result in a substantial adverse effect on a scenic vista, nor does the Project Site contain a scenic
vista. Impacts would be less than significant.
4.1b 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. There are no officially designated or eligible State Scenic Highways and no scenic
resources such as trees, rock outcroppings, or historic buildings within a State scenic highway
either adjacent to or in direct view from the site that would be removed, modified or altered by
the Project.8 The closest State Scenic Highway to the Project is Route 2 near the City of La Cañada
Flintridge, over 15 miles north of the Project Site. Therefore, the Project would not damage scenic
resources within a State scenic highway. No impact would occur in this regard.
4.1c If in a non-urbanized area, 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 in an urbanized
area, would the project conflict with applicable zoning and other regulations governing
scenic quality?
Less Than Significant Impact. The Project Site is in an urbanized area of the City; therefore, the
applicable threshold with respect to the Project is whether the Project is consistent with
applicable zoning and other regulations governing scenic quality.
The Project Site has a General Plan land use designation of Office/Light Industrial. The primary
uses allowed within the General Plan land use designation include commercial development and
light industrial uses. The Project proposes a General Plan Amendment to change the existing land
use from Office/Light Industrial to High Density Residential. The High Density Residential use
allows many forms of attached housing: triplexes, fourplexes, apartments, and
7 Los Angeles County Department of Parks & Recreation, Whittier Narrows Golf Course, https://parks.lacounty.gov/whittier-
narrows-golf-course/. Accessed September 21, 2025.
8 California Department of Transportation (Caltrans), California State Scenic Highways,
https://dot.ca.gov/programs/design/lap-landscape-architecture-and-community-livability/lap-liv-i-scenic-highways. Accessed
September 21, 2025.
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condominiums/townhouses, and small lot or clustered detached units. The maximum permitted
density is 30 units per acre.9
The Project Site is located within the C-3 Zone with a D-O. The Project proposes a Zoning
Amendment to change the existing zone from C-3 and D-O to Planned Development (P-D).
According to the RMC, the P-D Zone allows all land use designations in the RMC, except for high
intensity commercial, open space, and cemeteries.10 The P-D Zone is intended to provide for
residential, commercial, industrial, or institutional developments that are characterized by
innovative use and design concepts. The P-D Zone provides for new development to offer
amenities, quality, design excellence, and other similar benefits to the community.11
The Project’s design is inspired by Spanish and Prairie architecture and would complement
existing surrounding development. The row townhomes would include concrete ‘S’ roof tile,
decorative ceramic Spanish tile, arched balconies and porches, vertical sliding panel entry doors
and windows, and stucco trimmed windows and doors. The tandem townhomes would include
a low pitch roof with concrete roof tile, a stucco finish, and iron horizontal railings. Two distinctive
gateway monument signs would create a visually distinctive vehicle and pedestrian entrance for
the Project Site along Walnut Grove Avenue.
The Project would provide 126,015 sf of open space for residents and would plant new and a
variety of drought tolerant and native shrubs in the common open space areas and surrounding
the Project Site. The proposed trees and other landscaping along the exterior and within the
interior of the Project Site would help to create a visually attractive development and would
enhance the pedestrian environment.
The City does not have specific General Plan policies or zoning regulations related to scenic
quality that would apply to the Project. With approval of the General Plan Amendment and the
Zoning Amendment, the Project would be consistent with the uses intended for High Density
Residential land uses and P-D Zones. Therefore, impacts would be less than significant.
4.1d 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. Existing outdoor lighting at and near the Project Site includes safety
and security lighting associated with the two existing buildings on the Project Site, street lighting
along Walnut Grove Avenue, and vehicle lighting typical of urbanized areas. New light sources
introduced by the Project may increase ambient nighttime illumination levels.
9 City of Rosemead, 2021-2029 Housing Element, 2022, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/Adopted%20Rosemead%202021-2029%20Housing%20Element_CERTIFIED%20080122.pdf.
Accessed August 6, 2025.
10 City of Rosemead, Rosemead Municipal Code Title 17 Zoning, Article 2, Zoning Districts, Allowable Land Use and Zone Specific
Standards,
https://library.municode.com/ca/rosemead/codes/code_of_ordinances?nodeId=CD_ORD_TIT17ZO_ART2ZODIALLAUSZOECS
T. Accessed August 6, 2025.
11 City of Rosemead, Rosemead Municipal Code Title 17 Zoning, Chapter 17.24, Special Purpose Zoning Districts.
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Construction
Construction would be prohibited between the hours of 8 p.m. and 7 a.m. Monday through
Saturday and prohibited on Sunday or any Federal holiday, in accordance with RMC Chapter
8.36.030, Exemptions. No nighttime construction activities are anticipated.
While the majority of Project construction would occur during daylight hours, there is a potential
that construction could require the use of artificial lighting, particularly during the winter season
when daylight is no longer sufficient earlier in the day. To the extent artificial light sources are
required, such use would be temporary and only during the permitted construction hours, and
would cease upon completion of Project construction. Furthermore, construction-related
illumination would be used for safety and security purposes only, in compliance with RMC
Chapter 17.88 (Lighting). Additionally, as part of the Project, construction lighting would be
shielded to minimize light spillover. Construction lighting, while potentially bright, would be
focused on the particular area undergoing work.
Daytime glare could potentially occur during construction activities if reflective construction
materials were positioned in highly visible locations where the reflection of sunlight could occur.
However, any glare would be highly transitory and short-term, given the movement of
construction equipment and materials within the construction area, and the temporary nature
of construction activities. In addition, large, flat surfaces that generate substantial glare are
typically not an element of construction activities. Furthermore, temporary construction fencing
comprised of a solid material or including screening would be placed along the periphery of the
Project Site to screen construction activity from view at the street view at off-site locations.
Therefore, there would be a negligible potential for daytime or nighttime glare associated with
construction activities to occur.
Based on the above, light and glare associated with Project construction activities would not
create a new source of substantial light or glare which would adversely affect day or nighttime
views in the area. Therefore, impacts related to light and glare during construction would be less
than significant.
Operation
The Project would introduce new sources of light and glare that are typically associated with
residential development, including architecture, interior, security, entryway, and wayfinding
lighting sources. In addition, there would be an incremental increase in the amount of light on
Walnut Grove Avenue from the headlights of the motor vehicles generated by the Project.
However, Walnut Grove Avenue is regularly utilized as a throughway, so the lighting from the
Project motor vehicles would not be a new source of light or glare and would be similar to the
existing lighting conditions that are currently present on Walnut Grove Avenue.
All Project lighting would comply with current energy standards and codes, while providing
efficient and effective on-site lighting that is more efficient than the lighting required by the
existing use at the time that it was built. Nighttime security lighting for the Project would be
provided to illuminate building entrances, parking areas, and internal roadways and walkways.
The nearest sensitive receptors in the vicinity of the Project Site are the residences to the west.
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The Project’s exterior lights would be wall- or ground-mounted and shielded away from adjacent
land uses and security lighting would be designed to prevent light trespass onto adjacent
properties. Furthermore, the Project would implement a lighting plan to ensure that the Project’s
lighting would not adversely affect the existing adjacent and surrounding land uses.
Regarding glare, daytime glare can result from sunlight reflecting from a shiny surface that would
interfere with the performance of an off-site activity, such as the operation of a motor vehicle.
Reflective surfaces can be associated with window glass and polished surfaces, such as metallic
trim. In general, sun reflection that has the greatest potential to interfere with driving occurs
from the lower stories of a structure. Similar to the existing development at the Project Site, sun
reflection from the Project would occur during periods in which the sun is low on the horizon and
when the point of reflection within the Project Site is in front of the driver, in the direction of
travel.
No sources of substantial glare are anticipated with implementation of the Project. Exterior
building materials for the Project would use various non-reflective material designed to minimize
the transmission of glare from the Project’s buildings and would not include polished metals. The
Project building would be prohibited from using highly reflective building materials such as
mirrored glass on exterior facades.
Based on the above, the Project would not create a new source of substantial light or glare that
would adversely affect day or nighttime views in the area. Therefore, impacts would be less than
significant.
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4.2 Agricultural and Forestry Resources
Environmental Issue
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 Department of Conservation as an optional model to use in assessing impacts on agriculture and
farmland. 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 non-agricultural
use?
X
b) Conflict with existing zoning for agricultural use, or
a Williamson Act contract? X
c) Conflict with existing zoning for, or cause rezoning
of, forest land (as defined in Public Resources Code
Section 12220(g)), timberland (as defined by Public
Resources Code Section 4526), or timberland zoned
Timberland Production (as defined by Government
Code Section 51104(g))?
X
d) Result in the loss of forest land or conversion of
forest land to non-forest use? X
e) Involve other changes in the existing environment
which, due to their location or nature, could result
in conversion of Farmland, to non-agricultural use
or conversion of forest land to non-forest use?
X
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Impact Analysis
4.2a Would the project convert Prime Farmland, Unique Farmland, or Farmland of Statewide
Importance (Farmland), as shown on the maps prepared pursuant to the Farmland
Mapping and Monitoring Program of the California Resources Agency, to
non-agricultural use?
4.2b Would the project conflict with existing zoning for agricultural use, or a Williamson Act
contract?
4.2c Would the project conflict with existing zoning for, or cause rezoning of, forest land (as
defined in Public Resources Code Section 12220(g)), timberland (as defined by Public
Resources Code Section 4526), or timberland zoned Timberland Production (as defined
by Government Code Section 51104(g))?
4.2d Would the project result in the loss of forest land or conversion of forest land to non-
forest use?
4.2e Would the project involve other changes in the existing environment which, due to their
location or nature, could result in conversion of Farmland to non-agricultural use or
conversion of forest land to non-forest use?
No Impact. According to the California Department of Conservation’s California Important
Farmland Finder, no Prime Farmland, Unique Farmland, or Farmland of Statewide or Local
Importance is mapped within or in the immediate vicinity of the Project Site.12 The Project Site
and its immediate surroundings are identified as “Urban and Built-Up Land”, which is land
occupied by structures with a building density of at least 1 unit to 1.5 acres. Further, there is no
land under the Williamson Act Contract in the City.13 Therefore, the Project would not conflict
with any existing Williamson Act Contract. The Project Site is zoned C-3 and D-O, and no
agricultural, forest land, or timberland zoning exists in the City. Therefore, no impact concerning
mapped farmlands, Williamson Act contracts, agricultural, forest, or timber land zoning, or future
conversion of forest land to non-forest use would occur.
12 California Department of Conservation (DOC), California Important Farmland Finder, 2022,
https://maps.conservation.ca.gov/dlrp/ciff/. Accessed on July 31, 2025.
13 DOC, California Williamson Act Enrollment Finder, 2022, https://maps.conservation.ca.gov/dlrp/WilliamsonAct/. Accessed on
July 31, 2025.
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4.3 Air Quality
This Section is based on the Air Quality Analysis Technical Memorandum prepared by Kimley-
Horn and Associates, Inc. (Kimley-Horn), which is included as Appendix A: Air Quality Analysis
Technical Memorandum.
Environmental Issue
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? X
b) Result in a cumulatively considerable net
increase of any criteria pollutant for which the
Project region is non-attainment under an
applicable federal or state ambient air quality
standard?
X
c) Expose sensitive receptors to substantial
pollutant concentrations? X
d) Result in other emissions (such as those leading
to odors) adversely affecting a substantial
number of people?
X
SCAQMD Thresholds
Regional Emissions Thresholds
The SCAQMD CEQA Air Quality Handbook provides significance thresholds, presented in Table
4.3-1: South Coast Air Quality Management District Significance Threshold, for volatile organic
compounds (VOC) (also referred to as ROG), NOX, CO, sulfur oxides (SOX), PM10, and PM2.5. The
thresholds apply to both construction and operation of land use development projects within the
SCAQMD jurisdictional boundaries. If the SCAQMD thresholds are exceeded, a potentially
significant impact may occur, and additional analysis is warranted to fully assess the significance
of impacts. However, ultimately the City, as the Lead Agency under CEQA, determines the
thresholds of significance for impacts.
Table 4.3-1: South Coast Air Quality Management District Significance Threshold
Criteria Air Pollutants and
Precursors (Regional)
Mass Daily Thresholds (pounds per day)
Construction Operations
Reactive Organic Gases
(ROG)1 75 55
Carbon Monoxide (CO) 550 550
Nitrogen Oxides (NOX) 100 55
Sulfur Oxides (SOX) 150 150
Coarse Particulate Matter
(PM10) 150 150
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Table 4.3-1: South Coast Air Quality Management District Significance Threshold
Criteria Air Pollutants and
Precursors (Regional)
Mass Daily Thresholds (pounds per day)
Construction Operations
Fine Particulate Matter
(PM2.5) 55 55
1. VOCs and ROGs are subsets of organic gases that are emitted from the incomplete combustion of hydrocarbons or other
carbon-based fuels. Although they represent slightly different subsets of organic gases, they are used interchangeably for
the purposes of this analysis.
Source: SCAQMD, SCAQMD Air Quality Significance Thresholds, March 2023.
Localized Significance Thresholds
The SCAQMD developed the LSTs for emissions of NO2, CO, PM10, and PM2.5 in response to the
SCAQMD Governing Boards' Environmental Justice Enhancement Initiative (I‐4). The SCAQMD
provided the Final Localized Significance Threshold Methodology (dated June 2003 [revised
2008]) to assist lead agencies in analyzing localized impacts associated with project-specific
emissions. LSTs represent the maximum emissions that can be generated at the Project Site that
are not expected to cause or substantially contribute to an exceedance of the most stringent
CAAQS or NAAQS. LSTs are based on the ambient concentrations of that pollutant within the
Project SRA, as demarcated by the SCAQMD, the distance to the nearest sensitive receptor, and
the Project Site acreage.
The SCAQMD’s Localized Significance Threshold Methodology provides on-site mass emissions
rate look-up tables. The Project Site is located within SCAQMD SRA 11 (South San Gabriel Valley).
LSTs are provided for source-receptor distances of 25, 50, 100, 200, and 500 meters. The nearest
sensitive receptors to the Project Site are the University of the West located adjacent to the south
within the City and residential uses located adjacent to the west within the County; refer to
Figure 3 of Appendix A. As the closest sensitive receptor distance within the look-up table is 25
meters, the SCAQMD recommends projects with boundaries located nearer than 25 meters from
the nearest receptor use the LSTs at 25 meters.14 Table 4.3-2: Local Significance Thresholds for
Construction and Operations summarizes the LSTs for 1-acre, 2-acre, and 5-acre projects in
SCAQMD SRA 11 with sensitive receptors located within 25 meters of the Project Site.
Table 4.3-2: Local Significance Thresholds for Construction and Operations
Daily Acres
Disturbed/Project
Size
Maximum Pounds per Day1
Construction Operations
NOx CO PM10 PM2.5 NOx CO PM10 PM2.5
1-Acre 83 673 5 4 83 673 1 1
2-Acres 121 1,031 7 5 121 1,031 2 2
5-Acres 183 1,814 14 9 183 1,814 4 2
1. Thresholds are for projects located within SRA 11 (South San Gabriel Valley) and 25 meters of a sensitive receptor.
Source: SCAQMD, Localized Significance Threshold Methodology, July 2008.
LSTs associated with all acreage categories are provided in Table 4.3-2 for informational purposes
and to demonstrate the LSTs increase as acreages increase. It should be noted that LSTs are
screening thresholds and are therefore conservative. The construction LST acreage is determined
14 South Coast Air Quality Management District, Final Localized Significance Threshold Methodology.
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based on the daily acreage disturbed by the Project. LST analysis for construction is required for
all projects that disturb 5-acres or less on a single day. The operational LST acreage is based on
the total area of the Project Site.
Localized Carbon Monoxide
In addition to the daily thresholds listed above, development associated with the Project would
also be subject to the CAAQS and NAAQS. These are addressed through an analysis of localized
CO impacts known as the CO “hot spots” analysis, which determines whether the change in the
level of service of an intersection as a result of the Project would have the potential to result in
exceedances of the CAAQS or NAAQS.
The 2003 AQMP is the most recent AQMP that addressed CO concentrations. As part of the 2003
AQMP CO Modeling Attainment Demonstration, an analysis was performed utilizing dispersion
modeling.15 As an initial screening step, if the average daily traffic (ADT) along a roadway segment
within the Project area would not exceed a threshold of 100,000 per day, then the project would
not need to prepare a detailed CO hot spot analysis.
Impact Analysis
4.3a Would the project conflict with or obstruct implementation of the applicable air quality
plan?
Less Than Significant Impact. As stated above, the Project is located within the SoCAB and is
under the jurisdiction of the SCAQMD. Pursuant to the FCAA, the SCAQMD is required to reduce
emissions of criteria pollutants for which the SoCAB is in nonattainment. To reduce such
emissions, the SCAQMD adopted the 2016 AQMP and 2022 AQMP (AQMPs).16 The AQMPs
establish a program of rules and regulations directed at reducing air pollutant emissions and
achieving CAAQS and NAAQS.
The AQMPs are a regional and multi-agency effort including the SCAQMD, CARB, SCAG, and U.S.
EPA. The AQMPs’ pollutant control strategies are based on the latest scientific and technical
information and planning assumptions, including the Regional Transportation Plan/Sustainable
Communities Strategy (RTP/SCS), and updated emission inventory methodologies for various
source categories, and SCAG’s latest growth forecasts. SCAG’s latest growth forecasts were defined
in consultation with local governments and with reference to local general plans.
Criteria for determining project consistency with the AQMP are defined by the following
indicators:
• Consistency Criterion No. 1: The Project will not result in an increase in the frequency or
severity of existing air quality violations, or cause or contribute to new violations, or delay
15 South Coast Air Quality Management District, Air Quality Management Plan, Appendix V, Modeling and Attainment
Demonstrations, 2003, https://www.aqmd.gov/home/air-quality/air-quality-management-plans/air-quality-mgt-plan/2003-
aqmp. Accessed August 27, 2025.
16 The 2016 AQMP (adopted in March 2017) was developed to address attainment of multiple O3 and PM2.5 standards. The 2022
AQMP (adopted in December 2022), was developed to address attainment of the 2015 8-hour O3 standard.
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the timely attainment of air quality standards or the interim emissions reductions
specified in the AQMP.
• Consistency Criterion No. 2: The Project will not exceed the assumptions in the AQMP or
increments based on the years of the Project build-out phase.
According to the SCAQMD’s CEQA Air Quality Handbook, the purpose of the consistency finding
is to determine if a project is inconsistent with the assumptions and objectives of the regional air
quality plans, and thus if it would interfere with the region’s ability to comply with CAAQS and
NAAQS.17
The violations to which Consistency Criterion No. 1 refers to are exceedances of the CAAQS or
NAAQS. As shown below, Project construction- and operational-related emissions would not
exceed the respective SCAQMD thresholds. As such, the Project would not result in an increase
in frequency or severity of existing air quality violations, or cause or contribute to new violations,
or delay the timely attainment of air quality standards or the interim emissions reductions
specified in the AQMPs. Therefore, the Project would be consistent with the first criterion.
Concerning Consistency Criterion No. 2, the 2022 AQMP contains air pollutant reduction
strategies based on SCAG’s growth forecasts included in the 2020-2045 RTP/SCS. SCAG’s growth
forecasts were defined in consultation with local governments and with reference to local
general plans. The Project Site is currently designated as Office/Light Industrial and zoned
Medium Commercial with a Design Overlay. Residential use developments are not permitted
under the Project Site’s existing designation and zoning. Therefore, the Project proposes a
General Plan Amendment to alter the existing designation from Office/Light Industrial to High
Density Residential and a zone change to change the existing zoning from Medium Commercial
to Planned Development.
The 2020-2045 RTP/SCS was adopted by SCAG on September 3, 2020. Growth forecasts prepared
by SCAG and contained in the 2020-2045 RTP/SCS indicate that the population within the City
would increase from 55,000 persons in 2016 to 60,300 persons in 2050, an increase of 5,300
persons.18 Based on an average household size of 3.8, the Project would develop 191 dwelling
units and would result in population growth of approximately 726 persons.19 The Project would
represent approximately 13.7 percent of the anticipated population increase for the City by 2045.
The household and population growth attributed to the Project would be consistent with the
Housing Element. Therefore, the Project would be consistent with the City’s General Plan and the
growth attributed to the Project would be accounted for in future SCAG growth projections.
Additionally, the development of residential uses in proximity to transit services and employment
opportunities would reduce the associated vehicle miles traveled (VMT) and vehicle emissions in
17 South Coast Air Quality Management District, CEQA Air Quality Handbook, 1993.
18 Southern California Association of Governments (SCAG), Connect SoCal 2024, Demographics and Growth Forecast, 2024,
https://www.scag.ca.gov/sites/default/files/2024-05/23-2987-tr-demographics-growth-forecast-final-040424.pdf. Accessed
August 12, 2025.
19 SCAG, Rosemead Local Profiles Report 2019, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/Adopted%20Rosemead%202021-2029%20Housing%20Element_CERTIFIED%20080122.pdf.
Accessed August 12, 2025.
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comparison to a project located in a non-urban environment. As such, the Project would be
generally consistent with the emissions forecasts in the AQMPs and AQMP control measures.
LSTs were developed to ensure no exceedances of the CAAQS or NAAQS would occur if regional
project emissions were below thresholds.20 As shown below, the localized emissions resulting
from Project implementation would not exceed the SCAQMD’s LSTs. As the Project would not
increase the frequency or severity of an existing air quality violation or cause or contribute to
new violations for air quality pollutants (including ROG, NOX, CO, SOX, PM10, and PM2.5), the
Project would not delay timely attainment of air quality standards or interim emission reductions
specified in the AQMPs. Therefore, the Project would be consistent with the second criterion and
SCAQMD consistency finding criteria. As such, impacts would be less than significant, and no
mitigation is required.
4.3b 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. The SoCAB is classified as non-attainment of the applicable NAAQS
and or CAAQS for O3 (precursor pollutants ROG and NOX), PM10, PM2.5, and lead (for the Los
Angeles County portion only, and is expected to be redesignated to attainment based on recent
monitoring21). The SoCAB is classified as attainment, maintenance, or unclassifiable for all other
criteria pollutants. Nonetheless, the analysis below discloses emissions and applicable
thresholds for O3 precursors, NO2, PM10, PM2.5, CO, and SO2. Emissions of lead, hydrogen
sulfide, sulfates, and vinyl chloride are not reported, because they would be minimal from the
construction and operation of a residential use.
Regional Construction Emissions
Project construction would generate short‐term emissions of criteria air pollutants. The criteria
pollutants of primary concern within the Project area include ozone‐ precursor pollutants (i.e.,
ROG and NOX), PM10, and PM2.5. Construction‐generated emissions are short term and of
temporary duration, lasting only as long as construction activities occur, but would be considered
a significant air quality impact if the pollutant emissions generated exceeded the SCAQMD’s
thresholds of significance. Sources of emissions during construction include motor vehicle
exhaust associated with construction equipment and worker trips and the movement of
construction equipment, especially on unpaved surfaces. Emissions of airborne particulate
matter are largely dependent on the amount of ground disturbance associated with site
preparation and grading activities, as well as weather conditions and the appropriate application
of water.
Project construction includes demolition, sitewide vegetation and natural material removal (site
preparation), grading, infrastructure improvements, building construction, paving, and
20 South Coast Air Quality Management District, Localized Significance Thresholds, https://www.aqmd.gov/home/rules-
compliance/ceqa/air-quality-analysis-handbook/localized-significance-thresholds. Accessed August 12, 2025.
21 SCAQMD, National Ambient Air Quality Standards (NAAQS) and California Ambient Air Quality Standards (CAAQS)
Attainment Status for South Coast Air Basin, https://www.aqmd.gov/docs/default-source/clean-air-plans/air-quality-
management-plans/naaqs-caaqs-feb2016.pdf?sfvrsn=23. Accessed April 21, 2024.
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architectural coating applications, as well as off-site infrastructure improvements (i.e., sidewalk
improvements and grind and overlay of Walnut Grove Avenue along the Project Site frontage).
Project construction‐generated emissions associated with on-site development and off-site
improvements were calculated using CalEEMod, which is designed to model emissions for land
use development projects based on typical construction requirements. It is conservatively
assumed that the demolition haul mileage would be the worst-case disposal site distance, and
the anticipated construction equipment would operate simultaneously during each construction
phase.
Fugitive dust emissions from construction may temporarily become a nuisance and potential
health hazard to those living and working nearby. Project construction would comply with
SCAQMD rules and regulations, including SCAQMD Rule 402 (Nuisance), Rule 403 (Fugitive Dust),
and Rule 1113 (Architectural Coatings). SCAQMD Rule 402 (Nuisance) prohibits the discharge of
air contaminants or other material that cause a nuisance. SCAQMD Rule 403 (Fugitive Dust)
requires fugitive dust control measures. SCAQMD Rule 1113 (Architectural Coatings) provides
specifications on painting practices and regulates the ROG content of paint. Project construction
would additionally comply with CARB’s anti-idling regulations, which prohibits heavy-duty diesel
vehicle idling for more than five minutes. SCAQMD Rule 403 was applied in CalEEMod to reduce
fugitive dust emissions. See Appendix A for more information regarding the construction
assumptions used in this analysis.
Table 4.3-3: Project Construction Emissions summarizes the short-term construction emissions
attributable to the Project.
Table 4.3-3: Project Construction Emissions
Calendar Year Emissions (pounds per day)1
ROG NOX CO SO2 PM10 PM2.5
2026 0.53 15.50 9.64 0.08 7.00 1.62
2027 8.05 15.01 25.60 0.08 6.99 1.61
2028 7.96 13.19 25.03 0.03 2.84 0.94
2029 7.40 9.44 20.44 0.03 2.59 0.78
Maximum Daily Emissions 8.05 15.50 25.60 0.08 7.00 1.62
SCAQMD Threshold 75 100 550 150 150 55
SCAQMD Threshold
Exceeded? No No No No No No
1. As recommended by the SCAQMD, emissions were calculated using CalEEMod version 2022.1. Worst-case seasonal
maximum daily emissions are reported.
2. SCAQMD Rule 403 Fugitive Dust applied for construction emissions. SCAQMD Rule 403 reduction/credits include: properly
maintain mobile and other construction equipment; replace ground cover in disturbed areas quickly; water exposed
surfaces three times daily; water all haul roads three times daily; and limit speeds on unpaved roads to 15 miles per hour.
Reductions percentages from the SCAQMD CEQA Handbook (Tables XI-A through XI-E) were applied.
Table 4.3-3 shows the Project’s regional construction emissions would not exceed the respective
SCAQMD threshold. Therefore, impacts would be less than significant, and no mitigation is
required.
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Regional Operational Emissions
Operational emissions would be primarily associated with mobile sources (motor vehicles from
Project-generated vehicle trips), area sources (hearths, consumer products, architectural
coatings, and landscape maintenance equipment), and energy emissions (electricity and non-
hearth natural gas usage). Operational‐generated emissions associated with the Project were
calculated using CalEEMod, which is designed to model emissions based on land use activity data
and the Project vehicle trip generation.
Table 4.3-4: Project Operational Emissions summarizes the operational emissions attributable
to the Project.
Table 4.3-4: Project Operational Emissions
Source Emissions (pounds per day)1
ROG NOX CO SO2 PM10 PM2.5
Mobile 3.98 3.06 34.06 0.09 8.44 2.18
Area2 10.00 0.10 10.86 <0.01 <0.01 <0.01
Energy3 0.03 0.48 0.40 <0.01 0.04 0.04
Total Emissions4 14.01 3.64 45.32 0.09 8.48 2.22
SCAQMD Threshold 55 55 550 150 150 55
SCAQMD Threshold Exceeded? No No No No No No
1. As recommended by the SCAQMD, emissions were calculated using CalEEMod version 2022.1. Worst-case seasonal
maximum daily emissions are reported.
2. The Project would comply with SCAQMD Rule 445 (Wood Burning), which prohibits the installation of wood burning devices
in new developments.
3. The townhouses would be all-electric and would not include natural gas devices. Natural gas would only be utilized in pool
and spa heating.
4. Totals may not add up exactly due to rounding in the modeling calculations.
As shown in Table 4.3-4, the Project’s regional operational emissions would not exceed the
respective SCAQMD thresholds. Therefore, impacts would be less than significant, and no
mitigation is required.
4.3c Would the project expose sensitive receptors to substantial pollutant concentrations?
Less Than Significant Impact.
Localized Construction Analysis
LSTs represent the maximum emissions of NOX, CO, PM10, and PM2.5 generated at a project site
that are not expected to cause or contribute to an exceedance of the CAAQS or NAAQS. The
SCAQMD’s methodology states that “off-site mobile emissions from the Project should not be
included in the emissions compared to LSTs.” Therefore, only the emissions included in the
CalEEMod “on-site” emissions outputs were considered for the LST analysis.
Since CalEEMod calculates construction emissions based on the number of equipment hours and
the maximum daily soil disturbance activity possible for each piece of equipment, Table 4.3-5:
Equipment-Specific Grading Rates was used to determine the maximum daily disturbed acreage
by the proposed Project for comparison to LSTs.
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Table 4.3-5: Equipment Specific Grading Rates
Construction
Phase
Equipment
Type
Equipment
Quantity
Acres Graded
per 8-Hour Day
Operating
Hours per Day
Acres
Graded per
Day
Grading Graders 1 0.5 8 0.5
Dozers 1 0.5 8 0.5
Total 1.0
Table 4.3-5 shows that Project construction is anticipated to disturb approximately 1-acre in a
single day. As the LST guidance provides thresholds for projects disturbing 1-, 2-, and 5-acres in
size, the LSTs for a 1-acre threshold were utilized for this analysis.
The LSTs are based on the ambient concentrations of that pollutant for each SRA and distance to
the nearest sensitive receptor. The Project Site is located in SCAQMD SRA 11 (South San Gabriel
Valley). LSTs are provided for distances of 25, 50, 100, 200, and 500 meters to sensitive receptors.
The sensitive receptors nearest the Project Site are the University of the West located adjacent
to the south within the City and residential uses located adjacent to the west within the County.
SCAQMD’s LST guidance recommends using the 25-meter threshold for receptors located 25
meters or less from the Project Site.22 Therefore, the LSTs for 1-acre at 25 meters in SRA 11 were
utilized for this analysis. Table 4.3-6: Localized Significance of Project Construction Emissions
summarizes the localized emissions during each construction phase.
Table 4.3-6: Localized Significance of Project Construction Emissions
Construction Phase Maximum Daily Emissions (pounds per day)1,2
NOX CO PM10 PM2.5
Individual Construction Phase
Demolition (2026) 3.50 4.96 3.86 0.67
Demolition (2027) 3.43 4.96 3.85 0.66
Site Preparation (2027) 0.99 1.91 0.03 0.03
Grading (2027) 12.25 13.45 2.38 1.39
Infrastructure Improvements (2027) 3.66 5.14 0.10 0.09
Building Construction (2027) 7.28 9.20 0.26 0.24
Building Construction (2028) 6.91 9.20 0.23 0.21
Building Construction (2029) 6.63 9.16 0.21 0.20
Paving (2027) 3.47 4.98 0.15 0.14
Paving (2028) 3.31 4.95 0.13 0.12
Architectural Coating (2027) 1.66 2.25 0.04 0.04
Architectural Coating (2028) 1.62 2.24 0.03 0.03
Architectural Coating (2029) 1.59 2.22 0.03 0.02
Roadway Paving (2029) 6.88 11.71 0.22 0.20
Overlapping Construction Phases3
Paving + Building Construction +
Architectural Coating (2027) 12.41 16.43 0.44 0.41
22 South Coast Air Quality Management District, Sample Construction Scenarios for Projects Less than Five Acres in Size, 2005,
https://www.aqmd.gov/docs/default-source/ceqa/handbook/localized-significance-thresholds/final-sample-construction-scenario-
report.pdf?sfvrsn=2. Accessed August 12, 2025.
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Table 4.3-6: Localized Significance of Project Construction Emissions
Construction Phase Maximum Daily Emissions (pounds per day)1,2
NOX CO PM10 PM2.5
Paving + Building Construction +
Architectural Coating (2028) 11.84 16.39 0.39 0.36
Building Construction + Architectural
Coating (2028) 8.53 11.43 0.26 0.24
Building Construction + Architectural
Coating (2029) 8.22 11.38 0.24 0.22
Maximum Daily Emissions 12.41 16.43 3.86 1.39
SCAQMD Localized Screening Threshold
(1-acre of disturbance at 25 meters) 83 673 5 4
SCAQMD Threshold Exceeded? No No No No
1. As recommended by the SCAQMD, emissions were calculated using CalEEMod version 2022.1. Worst-case seasonal
maximum daily emissions are reported.
2. SCAQMD Rule 403 Fugitive Dust applied for construction emissions. SCAQMD Rule 403 reduction/credits include:
properly maintain mobile and other construction equipment; replace ground cover in disturbed areas quickly; water
exposed surfaces three times daily; water all haul roads three times daily; and limit speeds on unpaved roads to 15
miles per hour. Reductions percentages from the SCAQMD CEQA Handbook (Tables XI-A through XI-E) were applied.
3. Totals may not add up exactly due to rounding in the modeling calculations.
Source: CalEEMod version 2022.1. Refer to Appendix A for the model outputs.
As shown in Table 4.3-6, pollutant emissions on the peak day of construction would not exceed
the respective SCAQMD LSTs and, thus, would not result in significant concentrations of
pollutants at the nearest sensitive receptors. Therefore, impacts would be less than significant,
and no mitigation is required.
Localized Operational Impacts
According to the SCAQMD Localized Significance Threshold Methodology, operational LSTs apply
to on-site sources. The Project Site is 9.28 acres. Since LSTs increase with acreage, the LSTs for 1-
acre is conservatively used to evaluate the approximately 9.3-acre Project Site. As recommended
by the SCAQMD, LSTs for 1-acre at 25 meters in SRA 11 were utilized in this analysis. The
operational emissions summarized in Table 4.3-7: Localized Significance of Operational
Emissions include all on‐site Project‐related stationary sources (area and energy sources).
Table 4.3-7: Localized Significance of Operational Emissions
Source/Activity Emissions (pounds per day)1
NOX CO PM10 PM2.5
Operational Emissions
On‐Site Emissions (Area + Energy Sources)1,2,3,4 0.58 11.27 0.04 0.04
SCAQMD Localized Screening Threshold
(1-acre at 25 meters) 83 673 1 1
Exceed SCAQMD Threshold? No No No No
1. As recommended by the SCAQMD, emissions were calculated using CalEEMod version 2022.1. Worst-case seasonal
maximum daily emissions are reported.
2. The Project would comply with SCAQMD Rule 445 (Wood Burning), which prohibits the installation of wood-burning devices
in new developments.
3. The townhouses would be all-electric and would not include use of natural gas for cooking or heating. Natural gas would
only be utilized in pool and spa heating.
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4. Totals may not add up exactly due to rounding in the modeling calculations.
Source: CalEEMod version 2022.1. Refer to Appendix A for model outputs.
As shown in Table 4.3-7, the maximum daily emissions during operations would not exceed the
respective SCAQMD LSTs and are not expected to result in significant concentrations of pollutants
at the nearest sensitive receptors. Therefore, impacts would be less than significant, and no
mitigation is required.
Carbon Monoxide Hotspots
An analysis of CO “hot spots” determines whether the change in the level of service of an
intersection from Project-related traffic would have the potential to result in exceedances of the
CAAQS or NAAQS. It has long been recognized that CO exceedances are caused by vehicular
emissions, primarily when vehicles are idling at intersections. With the turnover of older vehicles,
introduction of cleaner fuels, and implementation of control technology on industrial facilities,
CO concentrations have steadily declined in the SoCAB. Accordingly, with the steadily decreasing
CO emissions from vehicles, even very busy intersections do not result in exceedances of the CO
standard.
The SoCAB was re-designated as attainment in 2007 and CO hot spots are no longer addressed
in the SCAQMD’s AQMP. The SCAQMD 2003 AQMP is the most recent AQMP that addresses CO
concentrations. As part of the SCAQMD CO Hot Spot Analysis, the Wilshire Boulevard and Veteran
Avenue intersection, one of the most congested intersections in Southern California with an
average daily traffic volume of approximately 100,000 vehicles per day, was modeled for CO
concentrations. This modeling effort identified a CO concentration high of 4.6-parts per million
(ppm), which is well below the 35-ppm federal standard.
According to Replica HQ, Walnut Grove Avenue between Rush Street and Drayer Lane has an
existing average daily traffic volume (ADT) of 9,055.23 As CO hot spots were not experienced at
the Wilshire Boulevard and Veteran Avenue intersection even as it accommodated 100,000
vehicles daily, it can be reasonably inferred the 1,375 total daily vehicle trips attributable to the
Project would not generate CO hotspots at any intersection within the Project area. Therefore,
impacts would be less than significant, and no mitigation is required.
4.3d Would the project result in other emissions (such as those leading to odors) adversely
affecting a substantial number of people?
Less Than Significant Impact.
Construction Odors
Project construction would generate odors from equipment diesel exhaust, architectural coatings
containing VOCs, and paving activities. However, these odors would be temporary, are not
expected to affect a substantial number of people and would disperse rapidly. Additionally, the
23 ReplicaHQ, Replica Annual Average Daily Traffic (AADT) Data, 2024, https://www.replicahq.com/aadt. Accessed September 16,
2025.
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Project would be required to comply with SCAQMD Rule 402 (Nuisance) to prevent odor
nuisances on sensitive receptors. SCAQMD Rule 402 (Nuisance) 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 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.
Construction odors would be further minimized through Project compliance with heavy-duty
construction equipment idling requirements (California Code of Regulations, Title 13, Sections
2449(d)(3) and 2485,) and established regulations that address construction materials storage,
use, and disposal (CFR, Part 1926 – Safety and Health Regulations for Construction, Subpart H –
Materials Handling, Storage Use and Disposal, et al.). As such, impacts would be less than
significant, and no mitigation is required.
Operational Odors
The SCAQMD CEQA Air Quality Handbook identifies certain land uses as odor sources, such as
agriculture (farming and livestock), wastewater treatment plants, food processing plants,
chemical plants, composting facilities, refineries, landfills, dairies, and fiberglass molding. The
Project would not develop land uses that have been identified by the SCAQMD as odor sources.
As such, the Project would not create objectionable odors. Therefore, impacts would be less than
significant, and no mitigation is required.
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4.4 Biological Resources
Environmental Issue
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 Game or U.S. Fish and
Wildlife Service?
X
b) Have a substantial adverse effect on any riparian
habitat or other sensitive natural community identified
in local or regional plans, policies, regulations, or by the
California Department of Fish and Game or U.S. Fish and
Wildlife Service?
X
c) Have a substantial adverse effect on state or federally
protected wetlands (including, but not limited to,
marsh, vernal pool, coastal, etc.) through direct
removal, filling, hydrological interruption, or other
means?
X
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?
X
e) Conflict with any local policies or ordinances protecting
biological resources, such as a tree preservation policy
or ordinance?
X
f) Conflict with the provisions of an adopted Habitat
Conservation Plan, Natural Community Conservation
Plan, or other approved local, regional, or state habitat
conservation plan?
X
Impact Analysis
4.4a 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 Game or U.S. Fish and Wildlife Service?
Less Than Significant Impact With Mitigation Incorporated. The Project Site is occupied by
existing commercial office buildings and associated surface parking lot. There are approximately
78 ornamental trees existing on the Project Site, several of which are dying or in severe decline
in the rear parking lot.
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There are no candidate, sensitive, or special-status species on the Project Site. The following
ornamental trees are located on the Project Site:
• Crepe Myrtles (36) planted along the front parking lot and down the side drive aisles.
• Tristania trees (18) located in the rear parking lot.
• Liquidambar trees (8) located at the front and rear building entries.
• Jacaranda trees (4) located at both drive entries.
• Ash trees (3) along south property line.
• Magnolia trees (9) along the parkway within the right of way.
A review of the California Department of Fish and Wildlife (CDFW) California Natural Biodiversity
Database (CNDDB) QuickView Tool found 12 threatened or endangered wildlife species in the El
Monte Quadrangle, which is the Project Site’s quadrangle.24 The 12 species include the following
listed in Table 4.4-1: Endangered and/or Threatened Species in the Vicinity of the Project Site
below.
Table 4.4-1: Endangered and/or Threatened Species in the Vicinity of the Project Site
Common Name Scientific Name
Birds
Light-Footed Ridgway’s Rail Rallus obsoletus levipes
Willow Flycatcher Empidonax traillii
Western Yellow-billed Cuckoo Coccyzus americanus occidentalis
Southwestern Willow Flycatcher Empidonax traillii extimus
Least Bells Vireo Vireo bellii pusillus
Coastal California Gnatcatcher Polioptila californica californica
Bank Swallow Riparia riparia
Swainsons Hawk Buteo swainsoni
Bald Eagle Haliaeetus leucocephalus
Fish
Santa Ana Sucker Catostomus santaanae
Vascular Plants
Nevins barberry Berberis nevinii
Slender-horned Spineflower Dodecahema leptoceras
Source: CDFW, CNDDB QuickView Tool, 2025,
https://apps.wildlife.ca.gov/bios6/?tool=cnddbqv.
Project development would include removal of all the existing trees on-site except for the
Magnolia street trees on Walnut Grove Avenue which would remain. However, none of these are
24 California Department of Fish and Wildlife (CDFW), California Natural Biodiversity Database QuickView Tool, 2023,
https://apps.wildlife.ca.gov/bios6/?tool=cnddbqv. Accessed on July 31, 2025.
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candidate, sensitive, or special-status tree species. While this could cause adverse effects
through temporary habitat modifications, the Project would also plant 282 new trees, proving
substantial net new habitat for birds.
There is currently no native habitat within or near the Project Site to support the listed species
above. The Project Site is either out of range for these species or would not provide suitable
habitat due to its highly disturbed nature. However, the trees on the Project Site could provide
potential breeding and foraging habitat for these species which are protected under the
California Fish and Game Code (CFGC) Section 3503 and the Migratory Bird Treaty Act (MBTA).
Compliance with the CFGC and the MBTA is a mandatory regulatory requirement that ensures
the protection of migratory birds and nesting birds. The Project’s potential to impact these
species would be less than significant with mandatory compliance with the CFGC and MBTA.
Nevertheless, Mitigation Measure (MM) BIO-1, which would require Project construction to be
initiated prior to the nesting bird season and completion of a nesting bird survey of the Project
Site, would ensure compliance with the MBTA and the CFGC during Project-related construction
activities.
Mitigation Measure
MM BIO-1 Nesting Migratory Birds. During construction, grubbing, brushing, or tree removal
shall be conducted outside of the State identified nesting season for migratory
birds (i.e., typically February 1 through September 1), if possible. If such
construction activities cannot be conducted outside the nesting season, a Pre-
Construction Nesting Bird Survey of all on-site trees and trees within 250 feet of
the construction limits shall be conducted by a qualified biologist within three days
prior to initiating construction activities. If active nests are found during the Pre-
Construction Nesting Bird Survey, a Nesting Bird Plan (NBP) shall be prepared by
a qualified biologist and implemented during construction. At a minimum, the NBP
shall include guidelines for addressing active nests, establishing buffers,
monitoring, and reporting. The size and location of all buffer zones, if required,
shall be based on the nesting species, nesting sage, nest location, its sensitivity to
disturbance, and intensity and duration of the disturbance activity.
4.4b 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 California Department of Fish and Game or U.S. Fish and Wildlife Service?
4.4c 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. According to the United States Fish and Wildlife Service (USFWS) National Wetlands
Inventory, no riparian habitats or wetlands are present on or adjacent to the Project Site.25 The
nearest identified wetland is a freshwater forested wetland located approximately a half-mile
25 United States Fish and Wildlife Service, National Wetlands Inventory, 2021,
https://fwsprimary.wim.usgs.gov/wetlands/apps/wetlands-mapper/. Accessed on July 31, 2025.
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east of the Project Site in the City of South El Monte. The Project would not involve construction
or operational activities that would have potential to impact any nearby wetland. Therefore, the
Project would not have an adverse effect on riparian habitat or other sensitive natural
community or on state or federally protected wetlands. No impact would occur in this regard.
4.4d 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 With Mitigation Incorporated. The Project Site is developed with
existing buildings and surface parking and is not part of an established wildlife corridor. Project
development would occur within the Project Site and would not impact the movement of any
native wildlife species. The Whittier Narrows Golf Course is located to the east of the Project Site
and may contain wildlife such as birds and other avian species, reptiles, small mammals and
rodents. However, the Project Site is physically separated from the Whittier Narrows Golf Course
by Walnut Grove Avenue and the Project Site and surrounding areas to the east are highly
developed. The Project Site and adjacent commercial and residential uses are unlikely to present
suitable habitat for resident or migratory wildlife.
As previously stated under Response 4.4a, the Project would be required to comply with the
MBTA and CFGC, which would further protect migratory birds. Under MBTA provisions, it is
unlawful “by any means or manner to pursue, hunt, take, capture (or) kill” any migratory birds
except as permitted by regulations issued by the USFWS. The term “take” is defined by USFWS
regulation to mean to “pursue, hunt, shoot, wound, kill, trap, capture or collect” any migratory
bird or any part, nest or egg of any migratory bird covered by the conventions, or to attempt
those activities. In addition, the CFGC extends protection to non‐migratory birds identified as
resident game birds (CFGC Section 3500) and any birds in the orders Falconiformes or
Strigiformes (birds‐of‐prey) (CFGC Section 3503). Therefore, as the Project would require removal
and encroachment into trees that could provide nesting habitat for migratory birds, impacts
would potentially be significant. See additional discussion under Response 4.4a.
To address potential impacts to migratory birds, the Project would be subject to compliance with
MM BIO-1, which addresses construction activities during the nesting season. Therefore,
following compliance with the relevant regulatory framework and MM BIO-1, the Project’s
potential impacts to nesting migratory birds would be reduced to less than significant.
4.4e Would the project conflict with local policies or ordinances protecting biological
resources, such as a tree preservation policy or ordinance?
Less Than Significant Impact. Provisions for the removal and planting of trees and landscaping in
public and private property are addressed in the RMC Chapter 17.104, Oak Tree Preservation,
which creates conditions for oak tree preservation and requires that persons desiring to remove
oak trees apply for a tree removal permit. The Project Site does not contain any oak trees, and
no oak trees would be removed in connection with the proposed Project.
A number of existing ornamental trees will be removed to accommodate the Project. Most of the
ornamental trees on-site within the existing parking lot would be removed to accommodate the
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127 new residential buildings. The Project would not conflict with local policies or ordinances
protecting biological resources, and impacts would be less than significant.
4.4f Would the project conflict with the provisions of an adopted Habitat Conservation Plan,
Natural Community Conservation Plan, or other approved local, regional, or state
habitat conservation plan?
No Impact. No portions of the City are located within the boundaries of an adopted Habitat
Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or
State habitat conservation plan.26,27 Therefore, the Project would not result in conflicts with the
provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or
other approved local, regional, or state habitat conservation plan, and no impact would occur.
26 CDFW, NCCP Plan Summaries, 2023, https://wildlife.ca.gov/conservation/planning/nccp/plans. Accessed August 6, 2025.
27 Data Basin, Habitat Conservation Plan, California,
https://databasin.org/maps/new/#datasets=c116dd0d32df408cb44ece185d98731c. Accessed August 6, 2025.
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4.5 Cultural Resources
This Section is based on the Archaeological Resources Assessment for the 1515 Walnut Grove
Avenue Project, prepared by Kimley-Horn and Associates, and is included as Appendix B:
Archaeological Resources Assessment of this IS/MND.
Environmental Issue
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?
X
b) Cause a substantial adverse change in the
significance of an archaeological resource pursuant
to Section 15064.5?
X
c) Disturb any human remains, including those
interred outside of dedicated cemeteries? X
Impact Analysis
4.5a Would the project cause a substantial adverse change in the significance of a historical
resource pursuant to Section 15064.5?
No Impact. CEQA Guidelines Section 15064.5(a) generally defines a historic resource as a
resource that is: (1) listed in, or eligible for listing in the California Register of Historical Resources
(California Register); (2) listed in a local register of historical resources (as defined in Section
5020.1(k) of the PRC) or identified as significant in a historical resources survey meeting the
criteria in Section 5024.1(g) of the PRC; and/or (3) determined to be a historical resource by a
project’s lead agency. Any object, building, structure, site, area, place, record, or manuscript
which a Lead Agency determines to be historically significant or significant in the architectural,
engineering, scientific, economic, agricultural, educational, social, political, military, or cultural
annals of California may be considered a historical resource, provided the Lead Agency’s
determination is supported by substantial evidence in light of the whole record. Generally, a
resource is considered by the Lead Agency to be historically significant if the resource meets the
criteria for listing on the California Register.
The Project Site is currently developed with two vacant buildings built in 1982. The building was
formerly occupied by California Federal Bank, Tycor, and Countywide Home Loans for general
office purposes before SCE purchased the building in 2009. As noted in the Phase I Environmental
Site Assessment (Phase I ESA) (see Appendix G), the building was completely renovated in 2009.
Interior finishes were replaced, new bracing for seismic protection was added, and the existing
cafeteria was removed. The State-recommended threshold under which buildings may be
considered historic resources is a construction age of 50 years. Therefore, the buildings are not
considered to be historic resources as they do not meet the age requirements to be considered
to be a historic resource, nor are they listed on the California Register or local register.
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Additionally, as multiple tenants have been in the building since its construction, and since the
building had been recently renovated in 2009, it is unlikely that the building contains any
historically significant attributes or contributing features such that the building may be eligible
to be a historic resource. Therefore, the Project would not cause a substantial adverse change in
the significance of a historical resource, and no impact would occur.
4.5b Would the project cause a substantial adverse change in the significance of an
archaeological resource pursuant to Section 15064.5?
Less Than Significant Impact with Mitigation Incorporated. Kimley-Horn conducted an
archaeological records search at the South Central Coastal Information Center (SCCIC) on August
14, 2025, to identify any previously recorded archaeological resources or previously conducted
cultural resources studies within the record search area. The record search area was defined as
the Project area plus a half-mile buffer. The SCCIC reported 11 previous studies and 1
archaeological resource within the record search area. Out of the 11 previous studies, 5 studies
were conducted within the Project area, all 5 with negative results for any archaeological
resources. Of the 6 studies within the buffer area, all had negative results for archaeological
resources, with the exception of 1 recorded archaeological resource (P-19-001009) in the half-
mile buffer, which is a prehistoric artifact scatter situated approximately 0.40 miles southeast of
the Project area.
Kimley-Horn reviewed a database of historic maps and aerial imagery for the Project area.
Historic aerial imagery is available for the Project area from 1948 through present, and historic
topographic maps are available from 1894 through present. The aerials show that the Project
area was developed as farmland before the 1940s. By 1980, the Project area was vacant and no
longer operated as agricultural land. A commercial property was developed in the Project area
between 1980 and 1987. Little to no changes have occurred to the built environment since that
time.
In conclusion, Kimley-Horn did not identify any archaeological resources within the Project area.
As such, no archaeological resources that meet the definition of “Historical Resources” or
“Unique Archaeological Resources”, as defined by CEQA, have been identified within the Project
area. Archaeological resources are unlikely to be present on the surface or immediately
subsurface given the extent of previous development. However, there is a moderate
archaeological sensitivity and potential for buried prehistoric or historic-period archaeological
resources past the depths of fill due to the alluvial fan topography, underlying Holocene-age
geological deposits, previously recorded prehistoric site near the Project area, and prehistoric
and historic-era occupation in this region. If any archaeological resources are unearthed during
Project construction that meet the definition of a significant archaeological resource pursuant to
CEQA Guidelines Section 15064.5, and are disturbed or damaged by proposed Project
construction activities, impacts to these archaeological resources would be potentially
significant. Mitigation is thus required for the proposed Project that sets forth procedures to be
followed should subsurface resources be discovered.
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Accordingly, the Project would be required to implement MM CUL-1 through MM CUL-3 which
would reduce potential Project impacts to previously-undiscovered archaeological resources to
a less than significant level.
Mitigation Measures
MM CUL-1 Archaeological Resources Training. Prior to the issuance of any permit for ground-
disturbing activities, the Applicant shall provide evidence to the City that a
qualified professional archaeologist meeting Secretary of the Interior professional
qualifications (Project Archaeologist) has been retained.
An Archaeological Resources Training shall be provided to all construction
managers and construction personnel engaged in relevant job activities prior to
commencing any ground disturbance work within the Project area. The training
shall be prepared and conducted by the Project Archaeologist. The training
content shall include, but not be limited to, information about archaeological
resources in the vicinity, types of common archaeological resources in southern
California, and the procedures to be followed to protect any such resources in the
case of inadvertent discovery. The training may be discontinued when ground
disturbance activities for the Project are completed. Construction personnel shall
not be permitted to operate equipment within the construction area during the
relevant period unless they have attended the training.
MM CUL-2 Archaeological Monitoring. The Project Archaeologist or their designee
(Monitors) will conduct archaeological monitoring of all ground disturbing
activities within native, undisturbed soils. The Project Archaeologist will have the
ability to recommend monitoring be decreased or eliminated at any time, based
on the absence of cultural resources and/or indication of subsurface soils
possessing a low likelihood for significant intact resources.
MM CUL-3 Inadvertent Discovery of Archaeological Resources. In the event that any
archaeological resources are inadvertently discovered at the Project area, all work
shall temporarily halt within 50 feet of the find. The Applicant shall notify the City
and consult with the Project Archaeologist who shall record and evaluate the find.
If the find is determined to be significant, the Project Archaeologist shall
recommend a treatment plan to the City. If avoidance is determined to be
infeasible, other appropriate treatment measures (e.g., data recovery) shall be
instituted. Ground disturbing activities may resume once the recommendations
have been fully implemented.
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4.5c Would the project disturb any human remains, including those interred outside of
dedicated cemeteries?
Less Than Significant Impact. Given the Project Site has been subject to extensive disruption, the
potential to disturb or impact any human remains is unlikely. The Project area is not known to
contain any buried human remains, and it is not likely that human remains would be discovered
during construction. However, in the unlikely event human remains are encountered, the
construction contractors would be required by law to comply with California Health and Safety
Code Section 7050.5, Disturbance of Human Remains. According to Section 7050.5(b) and (c), if
human remains are discovered outside of a dedicated cemetery, the County Coroner must be
contacted, and if the Coroner recognizes the human remains to be those of a Native American or
has reason to believe that they are those of a Native American, the Coroner is required to contact
the Native American Heritage Commission (NAHC) by telephone within 24 hours. Pursuant to
California PRC Section 5097.98, whenever the NAHC receives notification of a discovery of Native
American human remains from a county coroner, the NAHC is required to immediately notify
those persons it believes to be most likely descended from the deceased Native American. The
descendants may, with the permission of the owner of the land, or his or her authorized
representative, inspect the site of the discovery of the Native American human remains and may
recommend to the owner or the person responsible for the excavation work means for treatment
or disposition, with appropriate dignity, of the human remains and any associated grave goods.
The descendants shall complete their inspection and make recommendations or preferences for
treatment within 48 hours of being granted access to the site. According to Public Resources
Code Section 5097.94(k), the NAHC is authorized to mediate disputes arising between
landowners and known descendants relating to the treatment and disposition of Native American
human burials, skeletal remains, and items associated with Native American burials. With
mandatory compliance to California Health and Safety Code Section 7050.5 and PRC Section
5097.98, any potential impacts to human remains, including human remains of Native American
ancestry, that may result from construction of the proposed Project would be less than
significant.
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4.6 Energy
This Section is based on the Energy Calculations, which are included in Appendix C: Energy
Calculation.
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Result in potentially significant environmental impact
due to wasteful, inefficient, or unnecessary
consumption of energy resources, during project
construction or operation?
X
b) Conflict with or obstruct a state or local plan for
renewable energy or energy efficiency? X
Regulatory Setting
Renewable Portfolio Standard Program28, 29
In 2002, California established its Renewable Portfolio Standard (RPS) program with the goal of
increasing the annual percentage of renewable energy in the State’s electricity mix by the
equivalent of at least one percent of sales, with an aggregate total of 20 percent by 2017. The
California Public Utilities Commission (CPUC) subsequently accelerated that goal to 2010 for retail
sellers of electricity (Public Utilities Code §399.15(b)(1)). Governor Schwarzenegger signed
Executive Order S-14-08 in 2008, increasing the target to 33 percent renewable energy by 2020.
In September 2009, Governor Schwarzenegger continued California’s commitment to the RPS by
signing Executive Order S‐21‐09, which directs under its AB 32 authority to enact regulations to
help the State meet its RPS goal of 33 percent renewable energy by 2020. In September 2010,
CARB adopted its Renewable Electricity Standard regulations, which require all of the State’s
load-serving entities to meet this target. In October 2015, Governor Brown signed SB 350 into
legislation, which requires retail sellers and publicly owned utilities to procure 50 percent of their
electricity from eligible renewable energy resources by 2030. Signed in 2018, SB 100 revised the
goal of the program to achieve the 50 percent renewable resources target by December 31, 2026,
and to achieve a 60 percent target by December 31, 2030. SB 100 established a further goal to
have an electric grid that is entirely powered by clean energy by 2045. Under SB 100, the State
cannot increase carbon emissions elsewhere in the western grid or allow resource shuffling to
achieve the 100 percent carbon-free electricity target.
28 California Public Utilities Commission, Renewable Portfolio Standard (RPS) Program, 2025, https://www.cpuc.ca.gov/rps/. Accessed
September 14, 2025.
29 The Renewable Portfolio Standard Program is a flexible, market-driven policy to ensure that the public benefits of wind, solar, biomass, and
geothermal energy continue to be realized as electricity markets become more competitive. The policy ensures that a minimum amount of
renewable energy is included in the portfolio of electricity resources serving a state or country.
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California Building Energy Efficiency Standards: Title 24, Part 6
The California Energy Code (CCR Title 24, Part 6) was created by the California Building Standards
Commission as part of the California Building Standards Code in 1978 to establish Statewide
building energy efficiency standards and reduce Statewide energy use. The Energy Code requires
the reduction of wasteful and unnecessary energy consumption in newly constructed and
existing buildings. The California Energy Commission (CEC) updates the Energy Code every three
years to allow for consideration and possible incorporation of new energy efficiency technologies
and methods.
In December 2024, the 2025 Energy Code was approved by the California Building Standards
Commission for inclusion into the California Building Standards Code. The 2025 Energy Code
encourages efficient electric heat pumps, establishes electric-ready requirements for new
homes, expands solar photovoltaic and battery storage standards, strengthens ventilation
standards, and more. Buildings whose permit applications are applied for on or after January 1,
2026, must comply with the 2025 Energy Code.
California Green Building Standards
The California Green Building Standards Code (CCR, Title 24, Part 11), commonly referred to as
the CALGreen Code, is a Statewide mandatory construction code that was developed and
adopted by the California Building Standards Commission and the California Department of
Housing and Community Development. CALGreen standards require new residential and
commercial buildings to comply with mandatory measures under five topical areas: planning and
design; energy efficiency; water efficiency and conservation; material conservation and resource
efficiency; and environmental quality. CALGreen also provides voluntary measures (CALGreen
Tier 1 and Tier 2) that local governments may adopt, which encourage or require additional
measures in the five green building topics. The most recent update to the CALGreen Code was
adopted in December 2024 (2025 CALGreen Code) and continues to improve upon the existing
standards for new construction of, and additions and alterations to, residential and non-
residential buildings. Buildings whose permit applications are applied for on or after January 1,
2026, must comply with the 2025 CALGreen Code.
CARB Scoping Plan
Adopted December 15, 2022, CARB’s 2022 Scoping Plan for Achieving Carbon Neutrality (2022
Scoping Plan) sets a path to achieve targets for carbon neutrality and reduce anthropogenic GHG
emissions by 85 percent below 1990 levels by 2045 in accordance with AB 1279. To achieve the
targets of AB 1279, the 2022 Scoping Plan relies on existing and emerging fossil fuel alternatives
and clean technologies, as well as carbon capture and storage. Specifically, the 2022 Scoping Plan
focuses on zero-emission transportation; phasing out use of fossil gas use for heating homes and
buildings; reducing chemical and refrigerants with high global warming potential (GWP);
providing communities with sustainable options for walking, biking, and public transit;
displacement of fossil-fuel fired electrical generation through use of renewable energy
alternatives (e.g., solar arrays and wind turbines); and scaling up new options such as green
hydrogen.
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The key elements of the 2022 CARB Scoping Plan focus on transportation. Specifically, the 2022
Scoping Plan aims to rapidly move towards zero-emission transportation (i.e., electrifying cars,
buses, trains, and trucks), which constitutes California’s single largest source of GHGs. The
regulations that impact the transportation sector are adopted and enforced by CARB on vehicle
manufacturers and are outside the jurisdiction and control of local governments. The 2022
Scoping Plan accelerates development of new regulations as well as amendments to strengthen
regulations and programs already in place.
City of Rosemead General Plan
The City of Rosemead General Plan Resource Management Element (Resource Management
Element) establishes goals and policies that relate to the conservation of energy and fuel
consumption within the City. The following Resource Management Element policies are
applicable to the Project:
Policy 4.2: Support programs that reduce air quality emissions related to vehicular
travel.
Policy 4.3: Support alternative transportation modes and technologies, and develop
bike- and pedestrian friendly neighborhoods and districts to reduce emissions
associated with automobile use.
Policy 4.4: Encourage energy conservation efforts and the incorporation of energy-
saving designs and features into new and refurbished buildings.
Impact Analysis
4.6a 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.
Construction Energy Consumption
Project construction would consist of demolition, site preparation, grading, infrastructure
improvements, building construction, paving, and architectural coating applications, as well as
off-site infrastructure improvements (i.e., sidewalk improvements and grind and overlay of
Walnut Grove Avenue along the Project Site frontage). Project construction would include
electricity use associated with water utilized for dust control, diesel fuel from on-road hauling
and vendor trips and off-road construction diesel equipment, as well as gasoline fuel from on-
road worker commute trips. Because construction activities typically do not require natural gas,
it is not included in the following discussion. Energy usage associated with Project construction
is summarized in Table 4.6-1: Project Construction Energy Consumption.
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Table 4.6-1: Project Construction Energy Consumption
Source Project
Consumption
Los Angeles County
Annual Energy
Consumption1, 2
Percentage of
Countywide
Consumption
Electricity GWh
Water 0.0014 64,896 0.0000021%
Diesel Gallons
Construction Equipment 53,820
516,888,488
0.010%
Haul and Vendor Trips 66,611 0.013%
Total 120,431 0.023%
Gasoline Gallons
Mobile Trips 45,946 3,360,848,920 0.0014%
GWh = gigawatt-hours
1. Los Angeles County electricity usage in 2024 (most recent data available). Source: California Energy Commission, Electricity Consumption,
https://www.energy.ca.gov/data-reports/energy-almanac/california-electricity-data/california-energy-consumption-dashboards-0.
Accessed September 14, 2025.
2. The anticipated Los Angeles County fuel usage in 2026 (the first construction year). Source: California Air Resources Board, EMFAC2021,
Emissions Inventory, 2022, https://arb.ca.gov/emfac/emissions-inventory/cd60f29daaedd924a75a9316202d7f56a9b573e5. Accessed
September 14, 2025.
Source: Refer to Appendix C for the energy calculations.
The methodology for each energy source is described in further detail below.
• Water Electricity. Electricity usage associated with water usage for construction dust
control was quantified based on the total gallons of water used during soil disturbing
activities and the energy intensity. The total gallons of water used was calculated based
on the daily acreage disturbed during grading and site preparation, the number of days
of soil disturbing activities, and the daily watering rate per acre disturbed. The daily acres
disturbed was calculated using the methodology described in Chapter 4.2 of the
CalEEMod User’s Guide Appendix C. The daily watering rate was 3,020 gallons per acre
from the Air and Waste Management Association’s Air Pollution Engineering Manual
(1992). The energy intensity value was from the CalEEMod User Guide Appendix G and
includes supply, distribution, and treatment factors for the South Coast Hydrologic
Region.
• Diesel and Gasoline Fuel. The construction diesel and gasoline fuel use was calculated
using the CalEEMod GHG emission outputs and conversion ratios from the Climate
Registry.
As shown in Table 4.6-1 the Project’s construction-related electrical demand would be
approximately 0.0014 gigawatt-hours (GWh) and would represent less than 0.01 percent of the
electricity usage within the County. SCE would provide electricity to the Project Site. SCE’s total
energy sales are projected to be 98,275 GWh of electricity in 2026 (the first year of Project
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construction).30 The Project construction electricity consumption of 0.0014 GWh would
represent less than 0.01 percent of SCE’s projected sales. Therefore, it is anticipated that SCE’s
existing and planned electricity capacity and electricity supplies would be sufficient to serve the
Project’s temporary construction electricity demand. As such, Project construction would not
result in wasteful, inefficient, or unnecessary consumption of electrical resources.
Table 4.6-1 shows Project construction is anticipated to consume approximately 120,431 gallons
of diesel and approximately 45,946 gallons of gasoline, which would represent approximately
0.023 percent of diesel use and 0.0014 percent of gasoline use within the County. Based on the
Project’s relatively low fuel use during construction compared to the County’s annual use, the
Project would not substantially affect existing energy fuel supplies or resources. Project
construction-related fuel use would be temporary, fluctuate according to the construction phase,
and cease with construction. Furthermore, Project compliance with the latest engine efficiency
emissions standards and CARB’s construction equipment idling requirements would minimize
unnecessary fuel consumption. As such, it is expected that existing and planned transportation
fuel supplies would be sufficient to serve the Project’s temporary construction demand and
Project construction would have a nominal effect on the local and regional energy supplies.
Impacts associated with Project construction energy consumption would be less than significant,
and no mitigation is required.
Operational Energy Consumption
Energy consumption associated with Project operations would occur from building electricity
use, water use, natural gas use, and transportation fuel use and is summarized in Table 4.6-2:
Annual Project Operational Energy Consumption.
Table 4.6-2: Annual Project Operational Energy Consumption
Source Project Consumption
Los Angeles County
Annual Energy
Consumption1, 2
Percentage Increase
Countywide
Consumption
Electricity GWh
Building 0.99
64,896
0.0015%
Water 0.056 0.000086%
Total 1.05 0.0016%
Natural Gas3 Million Therms
Pool and Spa 0.0018 2,830 0.000063%
Diesel Gallons
Mobile Trips 19,389 514,906,638 0.0038%
Gasoline Gallons
Mobile Trips 187,866 3,152,967,310 0.0060%
30 California Energy Commission. CEDU 2022 Baseline Forecast- SCE, Form 1.1.b: Electricity Sales by Sector, 2023,
https://www.energy.ca.gov/data-reports/reports/integrated-energy-policy-report/2022-integrated-energy-policy-report-update-2. Accessed
September 14, 2025.
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GWh = gigawatt-hours
1. Los Angeles County electricity and natural gas usage in 2024 (most recent data available). Source: California Energy Commission, California
Energy Consumption Dashboards, https://www.energy.ca.gov/data-reports/energy-almanac/california-electricity-data/california-energy-
consumption-dashboards. Accessed September 14, 2025.
2. The anticipated Los Angeles County fuel usage in 2029 (the first operational year). Source: California Air Resources Board, EMFAC2021,
Emissions Inventory, 2022, https://arb.ca.gov/emfac/emissions-inventory/cd60f29daaedd924a75a9316202d7f56a9b573e5. Accessed
September 14, 2025.
3. The buildings would be all-electric; however, the pool and spa would be heated utilizing natural gas.
Source: Refer to Appendix C for the energy calculations.
The methodology for each energy source is described in further detail below.
• Building Electricity: The townhouses would be all-electric and would not include natural
gas appliances. The operational building electricity usage was based on CalEEMod
defaults and land use activity data.
• Water Electricity: The electricity associated with operational indoor and outdoor water
usage was quantified using the annual water usage and energy intensity factor. The
annual water usage was based on CalEEMod defaults and land use activity data. The
indoor energy intensity value was from the CalEEMod User Guide Appendix G and includes
the supply, distribution, treatment, and wastewater factors for the South Coast
Hydrologic Region. The outdoor energy intensity value was from the CalEEMod User
Guide Appendix G and includes the supply, distribution and treatment factors for the
South Coast Hydrologic Region.
• Pool and Spa Natural Gas: The pool and spa would be heated utilizing natural gas. The
operational natural gas usage was calculated based on the total gallons of water and
natural gas usage factor. The total gallons of water used was quantified using the total
pool and spa volume and a conversion factor of 7.48 gallons of water per cubic feet. The
natural gas usage factor was 0.023 therms per gallon per year.31
• Diesel Truck and Gasoline Passenger Vehicle Trips: The gasoline and diesel fuel
associated with vehicular trips was calculated based on the CalEEMod default fleet mix,
total annual VMT from CalEEMod, and average fuel efficiency from the Department of
Transportation. The total annual VMT was based on the daily Project trip generation
(1,375 total daily vehicle trips)32 and CalEEMod default trip lengths.
Table 4.6-2 shows the Project’s annual operational electrical demand would total approximately
1.05 GWh, which would account for less than 0.01 percent of the County’s annual use. SCE’S
forecasted sales in 2029 (the first operational year) is anticipated to be 101,545 GWh.33 The
proposed Project would represent less than 0.01 percent of SCE’s projected sales. Project
implementation would result in a negligible energy demand increase compared to SCE’s overall
demand. Additionally, SCE would review the Project’s estimated electricity consumption to
31 City of Oakland/Oakland Unified School District, Energy Efficient Commercial Pool Program, Preliminary Facility Reports for DeFremery Pool,
Fremont Pool, Live Oak Pool, Lyons Pool, and Temescal Pool, 2006.
32 Kimley-Horn and Associates, Inc., Traffic Study for the Proposed 1515 Walnut Grove Avenue Project in the City of Rosemead, 2025.
33 California Energy Commission. CEDU 2022 Baseline Forecast- SCE, Form 1.1.b: Electricity Sales by Sector, 2023,
https://www.energy.ca.gov/data-reports/reports/integrated-energy-policy-report/2022-integrated-energy-policy-report-update-2. Accessed
September 14, 2025.
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ensure that the estimated power requirement would be accounted for in the total load growth
forecast for their service area and planned growth of the power system. As such, it is anticipated
that SCE’s existing and planned electricity capacity and supply would be sufficient to serve the
Project’s electricity demand. It is also noted that Project design and operations would be subject
to compliance with the latest CALGreen Code and Energy Code Standards.
Southern California Gas Company (SoCalGas) would provide natural gas to the Project Site. Table
4.6-2 shows the Project would consume 0.0018 million therms of natural, which would account
for less than 0.01 percent of the County’s annual use. According to the 2024 California Gas
Report,34 the natural gas consumption within SoCalGas’ planning area was approximately 2,428
million cubic feet per day in 2023. The natural gas consumption associated with Project
operations would account for approximately 0.08 percent of the natural gas consumption in the
SoCalGas planning area. As such, the Project’s consumption of natural gas is expected to fall
within SoCalGas’ projected consumption and supplies for the area. According to the United States
Energy Information Administration, the United States currently has over 86 years of natural gas
reserves based on the 2021 supply and consumption rate.35
As shown in Table 4.6-2 the Project is anticipated to consume approximately 19,389 gallons of
diesel and 187,866 gallons of gasoline. The Project’s operational fuel use would represent less
than 0.001 percent of diesel and gasoline use in the County. Diesel and gasoline are supplied by
widely distributed service stations within and around the City. Based on current proven reserves,
the global supply of crude oil, other liquid hydrocarbons, and biofuels is expected to be adequate
to meet the world’s demand for liquid fuels through 2050.36 Therefore, the proposed Project
would not result in a substantial demand for energy that would require expanded supplies or the
construction of other infrastructure or expansion of existing facilities.
None of the Project’s anticipated energy uses would exceed one percent of the corresponding
County use. Additionally, this analysis conservatively assumes Project demand is all new and does
not consider existing uses that are to be removed. Project buildings would comply with the
current energy efficiency requirements and would therefore be more energy efficient than the
existing less efficient buildings. Buildings adhering to the latest Energy and CALGreen Code would
be more energy efficient than buildings designed under prior codes. Therefore, Project
operations would not substantially affect existing energy or fuel supplies or resources.
Furthermore, the Project would comply with applicable energy standards and new capacity
would not be required. Project implementation would not result in inefficient, wasteful, or
unnecessary energy consumption. Impacts would be less than significant, and no mitigation is
required.
34 California Gas and Electric Utilities, 2024 California Gas Report, https://www.socalgas.com/sites/default/files/2024-08/2024-California-Gas-
Report-Final.pdf. Accessed September 15, 2025.
35 U.S. Energy Information Administration, Frequently Asked Questions, How Much Natural Gas Does the United States Have, and How Long
Will It Last?, 2024, https://www.eia.gov/tools/faqs/faq.php?id=58&t=8. Accessed September 25, 2024.
36 United States Energy Information Administration, California State Energy Consumption Profile, 2025,
https://www.eia.gov/state/print.php?sid=CA. Accessed September 8, 2025.
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4.6b Would the project conflict with or obstruct a state or local plan for renewable energy or
energy efficiency?
Less Than Significant Impact. Buildings adhering to the latest Energy and CALGreen Code would
be more energy efficient than buildings designed under prior codes. Since the Project’s design
and operations would comply with the 2025 Energy Code, 2025 CALGreen Code, and applicable
energy regulations, the proposed Project would be more energy efficient than the existing on-
site uses.
SCE, the Project’s electricity provider, is subject to the RPS program, which requires investor-
owned utilities, electric service providers, and community choice aggregators to increase total
procurement from eligible renewable energy resources to 33 percent by 2020 and 50 percent by
2030. As noted above, SB 100 revised the goal of the program to achieve the 50 percent
renewable resources target by December 31, 2026, and to achieve a 60 percent target by
December 31, 2030. Renewable energy is generally defined as energy that comes from resources
which are naturally replenished within a human timescale, such as sunlight, wind, tides, waves,
and geothermal heat. The SCE satisfies its renewable energy portfolio standards and consists of
approximately 37.6 percent of renewable energy sources. 37
Project compliance with State and local energy efficiency standards would ensure that the Project
would meet all applicable energy conservation policies and regulations. As such, the Project
would not conflict with or obstruct a State or local plan for renewable energy or energy efficiency.
Impacts would be less than significant, and no mitigation is required.
37 South California Edison, 2023 Power Content Label, Southern California Edison Company,
https://www.energy.ca.gov/filebrowser/download/7362. Accessed September 8, 2025.
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4.7 Geology and Soils
This Section is based on the Geotechnical Investigation Report and Fault Rupture Hazard
Investigation, both prepared by Leighton Consulting, Inc. (now Verdantas, Inc.), which are
included in Appendix D-1: Geotechnical Investigation Report and Appendix D-2: Fault Rupture
Hazard Investigation, respectively, as well as the Paleontological Resources Assessment for the
1515 Walnut Grove Avenue Project, prepared by Kimley-Horn, which is included in Appendix E:
Paleontological Resources Assessment.
Environmental Issue
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 42.38
X
ii) Strong seismic ground shaking? X
iii) Seismic-related ground failure, including
liquefaction? X
iv) Landslides? X
b) Result in substantial soil erosion or the loss of
topsoil? X
c) Be located on a geologic unit or soil that
is unstable, or that would become unstable as a
result of the Project, and potentially result in on- or
off-site landslide, lateral spreading, subsidence,
liquefaction or collapse?
X
d) Be located on expansive soil, as defined in Table 18-
1-B of the Uniform Building Code (1994), creating
substantial direct or indirect risks to life or
property?
X
e) Have soils incapable of adequately supporting the
use of septic tanks or alternative waste water
disposal systems where sewers are not available for
the disposal of waste water?
X
38 The Division of Mines and Geology is now known as the California Geological Survey.
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Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
f) Directly or indirectly destroy a unique
paleontological resource or site or unique geologic
feature?
X
Impact Analysis
4.7a.i Would the project directly or indirectly cause potential substantial adverse effects,
including the risk of loss, or death involving the 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 With Mitigation Incorporated. The Alquist-Priolo Earthquake Fault
Zoning Act was passed in 1972 to mitigate the hazard of surface faulting to structures for human
occupancy. The Act’s main purpose is to prevent the construction of buildings used for human
occupancy on the surface trace of active faults. The Act requires the State Geologist to establish
regulatory zones, known as Alquist-Priolo (AP) Earthquake Fault Zones, around the surface traces
of active faults and to issue appropriate maps.
The site-specific 2024 Fault Rupture Hazard Investigation prepared for the Project concluded that
faults previously inferred to cross the Project Site are either non-existent or not Holocene-active
and pose no planning constraints to the Project. The northeastern and southwestern corners of
the Project Site could not be investigated due to utility conflicts, so these areas have not been
cleared of faults, and cannot be built on unless additional studies are conducted. As discussed in
the 2024 Geotechnical Investigation Report prepared for this Project, Holocene-active faults have
been previously mapped across the Project Site, and the Project Site is located within a
designated Alquist-Priolo Earthquake Fault Zone.39 Therefore, a Fault Rupture Hazard
Investigation was prepared in 2024, and pertinent exploration data from the Fault Rupture
Hazard Investigation is included within the Geotechnical Investigation Report. Based on the
results of the Fault Rupture Hazard Investigation, it was determined that the Project Site is free
of northwest-trending Holocene-active faults per the current State definition, and no setbacks
are required. However, as noted above, the southwest and northeast corners of the site could
not be evaluated due to utility conflicts in the field. The Project does not include any building
structures in these corners, and areas excluded from the Earthquake Fault Zone evaluation would
consist of landscaping and park areas to comply with the Geotechnical Investigation Report
recommendations for structural setbacks of 15 feet in these areas unless subsequent
investigations are performed. Furthermore, the potential for north-northeast trending faults to
extend into the southern portion of the site has not been fully evaluated due to existing utility
conflicts.40 MM GEO-1 requires the Project to incorporate all recommendations within the
39 Leighton Consultants, Inc. Geotechnical Investigation, 2025.
40 Supplemental exploration completed at the City’s request evaluated the potential for a north-northeast trending fault to
extend into the Project Site. The results were inconclusive, but additional studies to further evaluate this issue could not be
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Geotechnical Investigation Report and Fault Rupture Hazard Investigation and that an
Engineering Geologist observe and monitor excavations and document the subsurface geologic
conditions as they are exposed during Project construction. In addition, because additional
subsurface studies cannot be conducted at this time in the southeastern portion of the Project
Site given the extensive network of utilities known to underlie the area, MM GEO-1 requires the
Geologist to review and document excavations that are sufficiently deep to expose Pleistocene-
aged deposits in the southeastern portion of the Project Site. In the event that Holocene-active
or age-undetermined faults are exposed during grading, MM GEO-1 requires the Geologist to
make additional geotechnical design recommendations consisting of structural setbacks and
changes to the design to be implemented in compliance with applicable regulations.
Moreover, the design of the proposed structures on-site would be designed to accommodate
seismic loading, pursuant to the most recent California Building Code (CBC), City Building Code,
and engineering design recommendations in the Geotechnical Investigation Report. The Project
would comply with plan review and permitting requirements of the City before the start of
construction, as well as comply with the recommendations provided in the Geotechnical
Investigation Report that is subject to review and approval by the City. Therefore, with the
implementation of design parameters, compliance with applicable building codes, and MM GEO-
1, the Project would not result in substantial damage to structures or infrastructure or expose
people to substantial risk of injury involving the rupture of a known earthquake fault. Impacts
from fault rupture would be less than significant with mitigation incorporated.
Mitigation Measure
MM GEO-1 Geotechnical Design Recommendations. The Project shall incorporate all
recommendations within the Geotechnical Investigation Report and Fault Rupture
Hazard Investigations, and any supplemental geologic studies prepared for the
Project pursuant to this mitigation measure. Recommendations include
specifications for design of foundations, seismic design considerations, floor slabs,
retaining structures, paving, and grading. The final Geotechnical Investigation
Report, including design-level recommendations, shall be approved by the City’s
Building and Safety Division prior to the issuance of Building permits.
A California-licensed Engineering Geologist shall observe all excavations and
document the subsurface geologic conditions as they are exposed during
development of the entire buildable area of the site. In the southeastern portion
of the site (a rectangular area approximately 50 to 60 feet north of the southern
property line and 180 to 250 feet west of the eastern property line at Walnut
Grove Avenue) once the existing southern drive aisle and utilities are removed
during grading, the Geologist shall review and document an excavation or series
of excavations that are sufficiently deep to expose Pleistocene-aged deposits. Any
features indicative of faulting shall be logged, mapped, and evaluated in
accordance with CGS Special Publication 42. If Holocene-active or age-
conducted due to the extensive network of utilities in the area. Verdantas, Inc., Supplemental CPT Exploration for Fault Hazard
Assessment, January 15, 2026 and Verdantas, Inc. Response to City of Rosemead Geological Report Review, June 18, 2026.
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undetermined faults are identified, the Geologist shall, if needed, conduct
additional focused investigations and/or make additional geotechnical design
recommendations, such as the establishment of appropriate building setbacks and
modifications of site design, to ensure compliance with applicable regulations. If
faulting is observed during grading, the City’s geological consultant shall be
notified immediately and a site meeting scheduled. The Project Geologist shall
prepare and submit a final as-graded geological report that summarizes the
observations made during development of the Project Site.
4.7a.ii Would the project directly or indirectly cause potential substantial adverse effects,
including the risk of loss, or death involving strong seismic ground shaking?
Less Than Significant Impact With Mitigation Incorporated. The Project Site is within the
Southern California region, a seismically active area, and thus, the Project is exposed to potential
risk involving strong seismic ground shaking. The Project would be subject to compliance with
the most recent CBC and City Building Code, which are intended to minimize potential risk
involving seismic ground shaking. The Project would also be required to adhere to engineering
design recommendations presented in the Geotechnical Investigation Report as identified in MM
GEO-1. Therefore, following compliance with the established regulatory framework and
recommendations provided by the Geotechnical Investigation Report (MM GEO-1), the Project
would not cause potential substantial adverse effects involving strong seismic ground shaking,
and impacts would be less than significant with mitigation incorporated.
4.7a.iii Would the project directly or indirectly cause potential substantial adverse effects,
including the risk of loss, or death involving seismic‐related ground failure, including
liquefaction?
Less Than Significant Impact. Liquefaction is a seismic phenomenon in which loose, saturated,
relatively uniform fine- to medium-grained clean cohesionless soils behave similarly to a fluid
when subjected to high-intensity and long-duration ground shaking. Three criteria must be met
for liquefaction to occur: 1) loose, clean granular soils, 2) shallow groundwater, and 3) strong,
long-duration ground shaking.
According to the Geotechnical Investigation Report, the Project Site is primarily underlain by
sands with interbedded silts and clays. The Geotechnical Investigation Report’s review of the
California Geological Survey’s Earthquake Zones of Required Investigation for the El Monte
Quadrangle Map indicates that the Project Site is within an area potentially susceptible to
liquefaction. However, based on further analysis, the Geotechnical Investigation Report found
that the liquefaction potential index is low and the potentially liquefiable layers identified at
depths below 40 feet would not be a concern for surface manifestations of liquefaction at the
ground surface. Thus, the potential for liquefaction and surface manifestations are low at the
Project Site. Therefore, for the reasons stated above, impacts regarding risk of loss, or death
involving seismic-related ground failure, including liquefaction, would be less than significant.
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4.7a.iv Would the project directly or indirectly cause potential substantial adverse effects,
including the risk of loss, or death involving landslides?
Less Than Significant Impact. Landslides are mass movements of the ground that include rock
falls, relatively shallow slumping and sliding of soil, and deeper rotational or transitional
movement of soil or rock. According to the Geotechnical Investigation Report, the Project Site is
not located in an area mapped as potentially susceptible to seismically-induced landslides, and
no significant slopes are located on or near the site. No landslides are mapped or known to exist
at the Project Site or vicinity. The closest landslide zone is located approximately 0.6 miles south
of the Project Site. Therefore, the potential for seismically-induced landslides to impact the
Project Site is low, and the Project would not cause adverse effects involving landslides. Impacts
would be less than significant.
4.7b Would the project result in substantial soil erosion or the loss of topsoil?
Less Than Significant Impact. The Project Site is located on relatively level ground (with
elevations ranging from approximately 229 to 238 feet above mean sea level), which would
reduce the likelihood of soil erosion. However, earthmoving activities associated with proposed
demolition and construction activities have the potential to result in soil erosion or the loss of
topsoil. Development of the Project would be subject to local and State regulations for erosion
control and grading during construction. For example, the Project would be required to comply
with the Construction General Permit (CGP) issued by the State Water Resources Control Board
(SWRCB), effective September 1, 2023, which regulates construction activities to minimize water
pollution, including sediment risk from construction activities to receiving waters. Project
development would be subject to the National Pollution Discharge Elimination System (NPDES)
program, including the development and implementation of a Stormwater Pollution Prevention
Plan (SWPPP), which is further discussed in Section 4.10: Hydrology and Water Quality. The
Project’s construction contractor would be required to prepare and implement a SWPPP and
associated best management practices (BMPs) in compliance with the CGP during grading and
construction activities. Typical construction BMPs include, but are not limited to, watering soil,
soil cover of inactive areas, gravel bags, and fiber rolls.
Additionally, after Project completion, the Project Site would be developed with new high density
residential facilities, common open space and residential amenities, parking, and associated
hardscape and landscape improvements. All landscaped areas would be required to comply with
the provisions of RMC Chapter 13.08, Water-Efficient Landscapes. The Project would also
implement operational BMPs and Low Impact Development (LID) standards in compliance with
the RMC Chapter 13.16, Storm Water Management, which requires stormwater and urban runoff
pollution prevention controls; see Section 4.10: Hydrology and Water Quality for more
information on operational BMPs. Implementation of the BMPs and LID standards would help
ensure that soil erosion would not occur during the Project’s operation phase. BMP
implementation would be ensured through the City’s building plan check and development
review process.
For the reasons listed above, the Project would not result in substantial soil erosion or the loss of
topsoil, and impacts would be less than significant.
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4.7c 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 Site would likely not be subject to seismically-induced
liquefaction (see Response 4.7a.iii) or landslides (see Response 4.7a.iv).
For lateral spreading to occur, the liquefiable zone must be continuous, unconstrained laterally,
and free to move along gently sloping ground toward an unconfined area. As liquefaction
potential was found to be low at the Project Site (see Response 4.7a.iii), earthquake-induced
lateral spreading is also not considered a hazard at the Project Site. Therefore, there would be
less than significant impact associated with lateral spreading.
Ground surface subsidence generally results from the extraction of fluids or gas from the
subsurface, which can result in a gradual lowering of the ground level. The Project Site is not
mapped in an area of subsidence by the U.S. Geological Survey.41 Furthermore, the Project would
not involve any dewatering activities that could cause ground subsidence on the Project Site.
Therefore, the potential for ground collapse and other adverse effects due to subsidence to occur
on the Project site is considered low, and impacts associated with subsidence would be less than
significant.
Regarding collapsible soils, the results of the testing of soil samples conducted for the
Geotechnical Investigation indicated that on-site soils exhibit low compressibility characteristics.
Furthermore, the structural loads for the anticipated wood-framed residential development are
expected to be relatively light. Therefore, the Project’s potential for collapse is considered low,
and impacts associated with collapse would be less than significant.
For the reasons substantiated above, Project development would not cause substantial hazards
arising from unstable soils. Impacts would be less than significant.
4.7d 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 risk to life or property?
Less Than Significant Impact With Mitigation Incorporated. According to the Geotechnical
Investigation Report, a combined evaluation of test results from past on-site geotechnical surveys
and the current Geotechnical Investigation Report for this Project indicates that the soils within
the Project Site have a very low to low potential for expansion. Therefore, conservatively, the
Project Site’s expansion potential is considered to be low. The Project would be designed and
constructed in accordance with relevant federal, State, and City regulations. Additionally,
engineering design recommendations in the Geotechnical Investigation Report indicate that
onsite soils, less any deleterious material or organic matter, are suitable for use in required fills,
and any required import material should consist of relatively non-expansive soils with a very low
to low expansion index. MM GEO-1 requires the Project to incorporate all recommendations
within the Geotechnical Investigation Report, and the City would verify compliance with MM
41 United States Geological Survey, Areas of Land Subsidence in California,
https://ca.water.usgs.gov/land_subsidence/california-subsidence-areas.html. Accessed August 14, 2025.
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GEO-1 and the Geotechnical Investigation Report recommendations through the Project’s
Building Permit process. Therefore, following compliance with pertinent regulations and
implementation of MM GEO-1, the Project would not create substantial risk involving expansive
soils, and impacts would be less than significant with mitigation incorporated.
4.7e 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 Project would construct sewer laterals that would connect to existing sewer lines
in surrounding roadways. The Project does not propose using septic tanks or alternative
wastewater disposal systems. Temporary sanitary systems would be brought in during
construction and removed when the Project becomes operational. Therefore, no impact would
occur in this regard.
4.7f Would the project directly or indirectly destroy a unique paleontological resource or site
or unique geologic feature?
Less Than Significant Impact With Mitigation Incorporated. Paleontological resources are the
fossilized remains of organisms from prehistoric environments found in geologic strata. These
resources are valued for the information they yield about the earth’s history and its past
ecological settings. The potential for fossil occurrence depends on the rock type exposed at the
surface in a given area. According to the Geotechnical Investigation Report, the Project Site is
underlain by Quaternary age young alluvial fan deposits which consist of sands with interbedded
silts and clays.
Kimley-Horn conducted a paleontological record search for the Project area and vicinity through
the Natural History Museum of Los Angeles County (NHMLAC). The repository responded on
August 10, 2025, and indicated that no previously recorded fossil localities were identified in the
Project area. However, NHMLAC noted that fossil localities have been recorded near the Project
area. Kimley-Horn also reviewed the University of California Museum of Paleontology (UCMP)
online database to identify any previously recorded paleontological resources in the Project area
or vicinity. The UCMP did not report any fossil localities in this portion of Los Angeles County that
date to the Holocene or Pleistocene epochs.
The Project area contains geologic deposits of young geologic age and, therefore, has a low
paleontological sensitivity. While the paleontological sensitivity of the Project area is low, there
is still potential for paleontological resources to be inadvertently discovered during construction
depending on the depth of proposed disturbance and the location of deeper, older soils
underlying the mapped Holocene-aged deposits, and impacts would be potentially significant.
With implementation of MM GEO-2 which outlines the process for inadvertent discovery of
paleontological resources, potential impacts to paleontological resources would be reduced to
less than significant.
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Mitigation Measure
MM GEO-2 Inadvertent Discoveries of Paleontological Resources. Should paleontological
resources be inadvertently encountered, construction activities shall be
temporarily halted within 50 feet of the find so that the resource can be evaluated
by a paleontologist meeting the Society of Vertebrate Paleontology (SVP)
professional qualifications. A paleontologist shall temporarily divert or redirect
grading and excavation activities in the area of the exposed material to facilitate
evaluation and, if necessary, salvage. The paleontologist shall then assess the
discovered material(s) and prepare a memorandum evaluating the impact. The
Applicant shall then comply with the recommendations of the evaluating
paleontologist, and a copy of the survey report shall be submitted to the Natural
History Museum of Los Angeles County. Ground disturbing activities may resume
once the paleontologist’s recommendations have been implemented.
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4.8 Greenhouse Gas Emissions
This Section is based on the Greenhouse Gas Emissions Analysis Memorandum prepared by
Kimley-Horn, which is included in Appendix F: Greenhouse Gas Emissions Assessment Technical
Memorandum.
Environmental Issue
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?
X
b) Conflict with applicable plan, policy, or regulation
adopted for the purpose of reducing the emissions
of greenhouse gases?
X
Impact Analysis
4.8a 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 Emissions
Project construction would result in direct GHG emissions from construction equipment and the
transport of materials and construction workers to and from the Project Site. Construction‐
generated GHG emissions would be temporary and would cease with completion of construction.
Project construction is anticipated to occur over approximately 34 months. Project construction
includes demolition, sitewide vegetation and natural material removal (site preparation),
grading, infrastructure improvements, building construction, paving, and architectural coating
applications, as well as off-site infrastructure improvements (i.e., sidewalk improvements and
grind and overlay of Walnut Grove Avenue along the Project Site frontage). Construction‐
generated GHG emissions associated with the on-site development and off-site improvements
were calculated using CalEEMod, which is designed to model emissions for land use development
projects based on typical construction requirements. It is assumed the anticipated construction
equipment would operate simultaneously during each construction phase.
Table 4.8-1: Construction Greenhouse Gas Emissions presents the total GHG emissions
generated during Project construction. In accordance with the SCAQMD’s guidance, GHG
emissions from construction were amortized (i.e., averaged annually) over the lifetime of the
Project.42
42 The amortization period of 30-years is based on the standard assumption of the South Coast Air Quality Management District (South Coast
Air Quality Management District, Minutes for the GHG CEQA Significance Threshold Stakeholder Working Group #13, August 26, 2009).
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Table 4.8-1: Construction Greenhouse Gas Emissions
Year MTCO2e per year
Construction (2026) 350
Construction (2027) 389
Construction (2028) 594
Construction (2029) 294
Total 1,627
Amortized Over 30 Years 54
Source: CalEEMod version 2022.1. Refer to Appendix F for model outputs.
As shown in Table 4.8-2, Project construction would result in 1,627 MTCO2e over the course of
construction and approximately 54 MTCO2e per year when amortized.
Operational Emissions
Operational or long-term GHG emissions would occur over the life of the Project. Operational
GHG emissions would result from direct sources, such as Project-generated vehicular traffic,
natural gas combustion, and area source usage (hearths, consumer products, architectural
coatings, and landscape maintenance equipment). Operational GHG emissions would also result
from indirect sources, such as electrical power generation, water supply and wastewater
treatment, solid waste generation, and fugitive refrigerants from air conditioning or refrigerators.
Operational‐generated emissions associated with the Project were calculated using CalEEMod,
which is designed to model emissions based on land use activity data and the Project vehicle trip
generation. The townhouses would be all-electric except for the pool and spa, which would be
heated utilizing natural gas. The Project would generate 1,375 total daily vehicle trips.43
As shown in Table 4.8-2, the Project would generate approximately 1,913 MTCO2e per year from
operations with amortized construction. Project GHG emissions would not exceed SCAQMD’s
interim 3,000 MTCO2e per year threshold. Therefore, impacts would be less than significant, and
no mitigation is required.
43 Kimley-Horn and Associates, Inc., Traffic Study for the Proposed 1515 Walnut Grove Avenue Project in the City of Rosemead, 2025.
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Table 4.8-2: Project Operational Greenhouse Gas Emissions
Emissions Source MTCO2e per Year1
Construction Amortized Over 30 Years 54
Mobile 1,440
Area 12
Energy 336
Water and Wastewater 23
Waste 48
Refrigerants <1
Total Project Emissions1 1,913
SCAQMD Project Threshold 3,000
Threshold Exceeded? No
1. Total may not add up exactly due to rounding in the modeling calculations.
Source: CalEEMod version 2022.1. Refer to Appendix F for model outputs.
4.8b Would the project conflict with applicable plan, policy, or regulation adopted for the
purpose of reducing the emissions of greenhouse gases?
Less Than Significant Impact.
CARB 2022 Scoping Plan
The 2022 Scoping Plan sets a path to achieve targets for carbon neutrality and reduce
anthropogenic GHG emissions by 85 percent below 1990 levels by 2045 in accordance with AB
1279. The 2022 Scoping Plan aims to achieve the AB 1279 targets primarily through ZE
transportation (e.g., electrifying cars, buses, trains, and trucks) and decarbonizing the electricity
and industrial sectors. The Project would be required to comply with applicable current and
future regulatory requirements promulgated through the 2022 Scoping Plan.
Statewide strategies to reduce GHG emissions in the latest 2022 Scoping Plan include
implementing SB 100, which would achieve 100 percent clean electricity by 2045; achieving 100
percent ZEV in 2035 through Advanced Clean Cars II44; and implementing the Advanced Clean
Fleets regulation to deploy ZEV buses and trucks.45 Additional transportation policies include the
Potential Phased Advanced Clean Equipment Regulation, Clean Off-Road Fleet Recognition
Program, In-use Off-Road Diesel-Fueled Fleets Regulation, and Amendments to the In-use Off-
Road Diesel-Fueled Fleets Regulation. The 2022 Scoping Plan would continue to implement SB
44 On May 22, 2025, the United States Senate voted to revoke the waiver granted by the Biden administration for the Advanced Clean Cars II
program. On June 12, 2025, the Trump Administration formally nullified the Advanced Clean Cars II program.
45 On January 13, 2025, CARB withdrew their requests for Clean Air Act waivers from the U.S. EPA needed to support four recently adopted
vehicle emissions regulations: (1) the Advanced Clean Fleets Regulations; (2) the In-Use Locomotive Regulations; (3) part of the Commercial
Harbor Craft and Ocean-Going Vessels At-Berth Regulations; and (4) part of the Transport Refrigeration Unit Engine Standards Regulations.
Therefore, implementation of these regulations is currently unknown.
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375. GHGs would be further reduced through the Cap-and-Trade Program carbon pricing and SB
905. SB 905 requires CARB to create the Carbon Capture, Removal, Utilization, and Storage
Program to evaluate, demonstrate, and regulate carbon dioxide removal projects and
technology.
As shown in Table 4.8-2, approximately 93 percent of the Project’s emissions are from energy
and mobile sources, which would be further reduced by the 2022 Scoping Plan actions described
above. The City has no control over vehicle emissions (approximately 75 percent of the Project’s
total emissions). However, these emissions would decline in the future due to Statewide
measures, as well as cleaner technology and fleet turnover. Furthermore, the Project would not
obstruct or interfere with efforts to increase ZEVs or State efforts to improve system efficiency.
Compliance with applicable State standards (e.g., continuation of the Cap-and-Trade regulation;
CARB’s Mobile Source Strategy, and Sustainable Freight Action Plan; Executive Order N-79-20; SB
100: renewable electricity portfolio improvements that require 60 percent renewable electricity
by 2030 and 100 percent renewable by 2045, etc.) would ensure consistency with State and
regional GHG reduction planning efforts. The Project would additionally comply with the Energy
Code and CALGreen Code, which require energy conservation features in new construction (e.g.,
high‐efficiency lighting, high‐efficiency heating, ventilating, and air‐conditioning systems,
thermal insulation, double‐glazed windows, water conserving plumbing fixtures). Conserving
energy usage would indirectly regulate and reduce GHG emissions. It is also noted that the
Project would not convert any Natural and Working Lands and/or decrease the State’s urban
forest carbon stock, which are areas of emphasis in the 2022 Scoping Plan. Furthermore, the
Project would develop residential land uses that would potentially reduce VMT and associated
GHG emissions for some residents.46
Regarding the 2050 goals under Executive Order S-3-05, it is not possible at this time to quantify
the emissions savings from future regulatory measures, as they have not yet been developed;
nevertheless, it can be anticipated that Project operations would benefit from applicable
measures enacted to meet State GHG reduction goals. Impacts would be less than significant.
CARB 2022 Scoping Plan Appendix D
The 2022 Scoping Plan Appendix D provides local jurisdictions with tools to reduce GHGs and
assist the state in meeting the ambitious targets set forth in the 2022 Scoping Plan. The 2022
Scoping Plan Appendix D focuses on Residential and Mixed-Use Projects.
The 2022 Scoping Plan Appendix D lists potential actions that support the State’s climate goals.
However, the 2022 Scoping Plan notes that the applicability and performance of the actions may
vary across the regions. The document is organized into two categories (A) examples of plan-level
GHG reduction actions that could be implemented by local governments and (B) examples of on-
site project design features and mitigation measures, that could be required of individual projects
under CEQA, if feasible, when the local jurisdiction is the lead agency. The Project would include
a majority of the feasible operational measures listed in the 2022 Scoping Plan Appendix D as
46 California Air Pollution Control Officers Association, Quantifying Greenhouse Gas Mitigation Measures, 2010. The California Air Pollution
Control Officers Association identifies that infill developments, such as the proposed Project, reduce VMT which reduces fuel consumption
and associated GHG emissions.
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design features. Some of the recommended operational measures include requiring drought-
tolerant landscaping and energy conserving appliances and fixtures.
The 2022 Scoping Plan Appendix D states that project consistency with the Scoping Plan can be
determined through consistency with a local Climate Action Plan that addresses the State’s
largest sources of emissions and prioritize transportation electrification, VMT reduction, and
building decarbonization. Project contributions to climate goals in relation to the largest sources
of emissions are discussed further below:
• Transportation Electrification. The 2022 Scoping Plan notes that to be clearly consistent
with the State’s goals, projects should provide electric vehicle charging infrastructure
that, at minimum, meets the most ambitious voluntary standard in the CALGreen Code.
The Project would be consistent with the CALGreen Code.
• VMT Reduction. The 2022 Scoping Plan includes strategies to increase access to public
transit by increasing density of development near transit. The Project would increase
residential density near transit options. The Project Site is located approximately 0.25-
mile (1,342 feet) from the Los Angeles County Metropolitan Transportation Authority 287
bus stop and approximately 0.33-mile (1,772 feet) from the Montebello Transit 20 San
Gabriel bus line.
• Building Decarbonization. Building decarbonization refers to emissions reduction
strategies including maximizing energy efficiency, use of low- and zero-carbon electricity,
demand flexibility, energy storage, use of very low- or no-GWP refrigerants, and
eliminating fuel combustion by electrifying appliances and equipment.47 The townhouses
would be all-electric except for the pool and spa which would utilize natural gas for
heating.
The Project would include project features aimed at increasing transportation electrification,
reducing VMT, and maximizing building decarbonization. Thus, the Project would not impede the
State’s progress towards carbon neutrality by 2045 under the 2022 Scoping Plan. As such, impacts
would be less than significant, and no mitigation is required.
SCAG RTP/SCS Consistency
Under SB 375, SCAG’s 2024-2050 RTP/SCS establishes GHG emissions goals to reduce GHG
emissions in the region by eight percent from 2005 levels by 2020 and by 19 percent by 2035.
The RTP/SCS is a long-range vision plan that balances future mobility and housing needs with
economic, environmental, and public health goals.
The 2024-2050 RTP/SCS is supported by a combination of transportation and land use strategies
that help the region achieve state GHG emissions reduction goals and FCAA requirements,
increased housing production, improved equity and resilience, the preservation of natural lands,
improvement of public health, increased transportation safety, support for the region’s vital
goods movement industries and more efficient use of resources. GHG emissions resulting from
47 California Air Resources Board, 2022 Scoping Plan for Achieving Carbon Neutrality, Appendix F – Building Decarbonization, 2022.
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land development-related mobile sources are the most potent source of emissions, and
therefore Project comparison to the 2024-2050 RTP/SCS is an appropriate indicator of whether
the Project would inhibit the post-2020 GHG reduction goals promulgated by the state.
Table 4.8-3: 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy
Consistency
SCAG Goals Compliance
Mobility: Build and maintain an integrated multimodal transportation network.
Support investments that are well-
maintained and operated,
coordinated, resilient and result in
improved safety, improved air quality
and minimized greenhouse gas
emissions
Consistent: This measure is to be taken at the
regional level. Project implementation would not
conflict with the goal. As discussed above, the
Project would be constructed in accordance with
Title 24 of the California Building Standards Code,
Title 20 of the CCR, and CALGreen Code standards.
Ensure that reliable, accessible,
affordable, and appealing travel
options are readily available, while
striving to enhance equity in the
offerings in high-need communities
Consistent: This measure is to be taken at the
regional level. Project implementation would not
conflict with the goal. The Project proposes a
residential development on an infill site in an
urban area near public transit services, transit
routes, SR 60, and SR 164. The Project Site location
would reduce VMT for some residents.
Support planning for people of all
ages, abilities, and backgrounds
Consistent: This measure is to be taken at the
regional level. Project implementation would not
conflict with the goal.
Communities: Develop, connect, and sustain communities that are livable and thriving
Create human-centered communities
in urban, suburban, and rural settings
to increase mobility options and
reduce travel distances
Consistent: The Project proposes a residential
development on an infill site in an urban area near
existing transit routes, SR 60, and SR 164. The
Project Site location would reduce VMT for some
residents.
Produce and preserve diverse housing
types in an effort to improve
affordability, accessibility, and
opportunities for all households
Consistent: The Project would include a variety of
unit sizes and types of townhomes to provide
options for future residents.
Environment: Create a healthy region for the people of today and tomorrow
Develop communities that are resilient
and can mitigate, adapt to, and
respond to chronic and acute stresses
Consistent. The Project proposes a residential
development on an infill site in an urban area near
existing transit routes, SR 60, and SR 164. The
Project Site location would reduce VMT for some
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Table 4.8-3: 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy
Consistency
SCAG Goals Compliance
and disruptions, such as climate
change
residents. The Project would be constructed in
accordance with Title 24 of the California Building
Standards Code, Title 20 of the California Code of
Regulations, and CALGreen Code standards. In
addition, the Project would comply with all
applicable efficiency requirements, provide
electric vehicle spaces, and include landscaping
with low water requirements.
The Project Site is located approximately 22 miles
inland and would therefore not be subject to risks
associated with sea level rise. The Project would
also provide central air conditioning in all units to
offer relief from increased exterior surface
temperatures. The Project thus promotes GHG-
reduction strategies and is well suited to
maintaining resiliency against the effects of
climate change and associated health impacts.
Integrate the region’s development
pattern and transportation network to
improve air quality, reduce
greenhouse gas emissions and enable
more sustainable use of energy and
water
Consistent. Although the Project does not include
transportation improvements, the Project Site is
located within an urban area near public transit
services, transit routes, SR 60, and SR 164. The
Project Site location would reduce trip lengths and
VMT, which would reduce mobile-source GHG and
air quality emissions. The reduction of energy use,
improvement of air quality, and promotion of
more environmentally sustainable development
are encouraged through development of
alternative transportation methods, green design
techniques for buildings, and other energy-
reducing techniques, such as, compliance with the
provisions of the California Building Energy
Efficiency Standards and the CALGreen Code.
Conserve the region’s resources Consistent. The Project Site is not designated for
agricultural uses, natural resources, or
conservation. Project implementation would not
result in a loss of the region’s resources.
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Table 4.8-3: 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy
Consistency
SCAG Goals Compliance
Economy: Support a sustainable, efficient, and productive regional economic
environment that provides opportunities for all people in the region
Improve access to jobs and
educational resources
Consistent. The Project proposes to develop
residential uses in an urban area. The Project Site
is located adjacent to commercial, institutional,
and recreational uses. Additionally, the Project
Site is located near public transit services, transit
routes, SR 60, and SR 164. The Project location
would increase housing density near employment
and educational resources.
Advance a resilient and efficient goods
movement system that supports the
economic vitality of the region,
attainment of clean air and quality of
life for our communities
Consistent: This measure is to be taken at the
regional level. Project implementation would not
conflict with the goal. As discussed above, the
Project would promote clean air and non-auto
travel by developing residential uses near existing
transit routes.
Source: Southern California Association of Governments, Connect SoCal (2024 – 2050 Regional Transportation
Plan/Sustainable Communities Strategy), 2024.
As shown in Table 4.8-3, the proposed Project would be consistent with the stated goals of the
2024-2050 RTP/SCS. Therefore, the proposed Project would not result in any significant impacts
or interfere with SCAG’s ability to achieve the region’s GHG emission reduction targets. Impacts
would be less than significant.
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4.9 Hazards and Hazardous Materials
This Section is based on the Phase I Environmental Site Assessment Report (ESA) and the Phase II
ESA Report, both prepared by Converse Consultants and are included in Appendix G: Phase I ESA
and Appendix H: Phase II ESA, respectively.
Environmental Issue
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?
X
b) Create a significant hazard to the public or the
environment through reasonably foreseeable upset
and accident conditions involving the release of
hazardous materials into the environment?
X
c) Emit hazardous emissions or handle hazardous or
acutely hazardous materials, substances, or waste
within one-quarter mile of an existing or proposed
school?
X
d) Be located on a site which is included on a list of
hazardous materials sites compiled pursuant to
Government Code Section 65962.5 and, as a result,
would it create a significant hazard to the public or the
environment?
X
e) For a project located within an airport land use plan or,
where such a plan has not been adopted, within two
miles of a public airport or public use airport, would the
project result in a safety hazard or excessive noise for
people residing or working in the project area?
X
f) Impair implementation of or physically interfere with
an adopted emergency response plan or emergency
evacuation plan?
X
g) Expose people or structures, either directly or
indirectly, to a significant risk of loss, injury or death
involving wildland fires?
X
Impact Analysis
4.9a 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. The Project involves the demolition of the existing SCE building and
central plant building and construction of 191 residential townhome units, parking, and
landscaping. Project construction would involve the transport, storage, use and/or disposal of
limited quantities of hazardous materials, such as fuels, solvents, degreasers, and paints. The use
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of these materials during Project construction would be short-term and would occur in
accordance with standard construction practices, as well as with applicable federal, State, and
local regulations. Potentially hazardous materials would be contained, stored, and used during
construction in accordance with manufacturers’ instructions and handled in compliance with
applicable standards and regulations. Examples of such activities include fueling and servicing
construction equipment and applying paints and other coatings. Project construction would be
temporary, and existing regulations of several agencies would govern these activities.
Construction activities would be subject to compliance with relevant regulatory requirements
and restrictions concerning the transport, use, or disposal to prevent a significant hazard to the
public or environment. The primary regulatory requirements include SCAQMD Rule 1166 (volatile
organic compound emissions) and Rule 1466 (fugitive dust toxic air contaminants)
The Project would not emit hazardous emissions or involve hazardous or acutely hazardous
materials, substances, or waste. However, the proposed Project could involve the use of
materials associated with routine maintenance of the property, such as janitorial supplies for
cleaning purposes and/or herbicides and pesticides for landscaping. All potentially hazardous
waste generated would be required to be disposed of according to the Occupational Safety and
Health Administration (OSHA) requirements. These uses would not involve the routine transport,
use, or disposal of quantities of hazardous materials that could create a significant hazard to the
public or environment. The hazardous materials used during operations would be stored,
handled, and disposed of in accordance with applicable regulations. Therefore, following
compliance with the regulatory requirements, the Project would not create a significant hazard
to the public or the environment through the routine transport, use, or disposal of hazardous
materials. Impacts would be less than significant.
4.9b 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 with Mitigation Incorporated.
Construction
Project construction would require digging and excavation that could result in the accidental
release of hazardous materials. According to the Phase I ESA, potential recognized environmental
conditions (RECs), historical RECs (HRECs), and significant data gaps were revealed:
• The historical pipe suction pumps for fuel oil supply and return located exterior to the
northwest corner of the SCE Building.
• Historical underground lube oil storage and waste tanks located exterior to the northwest
corner of the building.
• The historical use of the clarifier and interceptor.
• The historical creek traversing the Project Site potentially transporting agricultural
chemicals onto the Project Site.
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• Two historical 20,000-gallon underground storage tanks (USTs) exterior to the north and
northwest corner of the SCE building and subsequent closure by regulatory agencies.
• Historical underground lube oil storage and waste tanks located exterior to the northwest
corner of the SCE building.
The Phase II ESA was conducted to evaluate the environmental conditions related to the USTs,
the historical use of the clarifier and interceptor, and hazardous materials storage and operations
at the buildings on the Project Site. Additionally, soil vapor screening was conducted and
analyzed for VOCs and total petroleum hydrocarbons (TPH) using EPA Method 8260. See results
within Tables 1 through 5 of the Phase II ESA.
Regarding metals, a total of 12 metals were reported in one or more of the samples analyzed:
arsenic, barium, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel,
vanadium, and zinc. The maximum reported arsenic concentration in one sample exceeds the
background threshold of 12 milligrams per kilogram (mg/kg). All other arsenic concentrations
were less than the threshold. The arsenic concentration in the sample is isolated and considered
to be anomalous as arsenic was not detected in any of the surrounding borings or in the deeper
sample from the same location. The maximum concentrations of all other reported metals were
less than their respective EPA Regional Screening Levels (RSLs) for residential land uses.
A concentration of TPH in the gasoline range was reported in one sample, which was below the
RSL for residential land uses. Concentrations of TPH in the diesel range were reported in five
samples. Two samples exceeded the RSL for residential land uses, but all concentrations were
less than the RSLs for commercial land uses. These were likely to be related to a UST that was
formerly located in the vicinity of the sample location since the TPH was reportedly left in place
at the time the UST was removed in 1995. Concentrations of TPH in the oil range were reported
in nine samples, but all were below the RSL for residential land uses.
For semi-VOCs (SVOC), five SVOCs were reported in one sample. NO SVOCs were reported in any
of the other samples analyzed. With the exception of Benzo(a)pyrene, the concentrations of all
other reported analytes were less than their respective RSL for residential land use. The
Bendon(a)pyrene concentration was greater than the RSL for residential land use, but less than
the RSL for commercial land use.
Seventeen VOCs and TPH in the gasoline range were detected in one or more of the soil vapor
samples. Benzene was reported in 9 of the 43 samples analyzed, with 8 samples exceeding the
RSL for residential land use and 1 sample exceeding the RSL for commercial land use. The source
of the benzene is likely minor leaks from automobiles in the parking areas.
Bromodichloromethane was reported in 3 samples, all of which exceed the RSL for residential
land use, but not for commercial land use. Chloroform was reported in 19 samples, with 17
samples exceeding the RSL for residential land use and 6 samples exceeding the RSL for
commercial land use. The limited detections of chloroform and bromodichloromethane are
suspected to be caused by leaky water lines and/or infiltration of irrigation water.
Trichloroethylene was reported in 10 samples, 7 of which exceed the RSL for residential land use,
but not for commercial land use. These elevated concentrations were primarily detected in the
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vicinity of the central plant building and may be related to a degreasing product formerly used or
stored in the building. TPH-g was reported in 4 samples, with 1 exceeding the RSL for residential
land use and 1 sample exceeding the RSL for commercial land use. These elevated concentrations
were limited to the northern boundary of the Project Site in the vicinity of the former USTs. The
maximum concentrations of all other reported VOCs were less than their respective RSL for
residential land uses.
As recommended in the Phase II ESA, regarding the arsenic, benzo(a)pyrene, and TPH in the diesel
range, because the soils across the Project Site are recommended to be overexcavated and
recompacted, the slightly impacted soils would be blended with surrounding non-impacted soils
such that all remaining maximum concentrations would be less than the RSLs. No further action
would be warranted in that area. Regarding TPH in the diesel range, as the exceedance appears
to be related to releases from the former UST in the area, since regulatory closure was granted
for removal of the UST and no significant exposure pathway to concentrations remain at depths
of 15 and 20 feet below ground surface, no further action appears to be warranted related to
those concentrations.
Although several VOCs and TPH-g were reported at concentrations in excess of residential and/or
commercial screening levels, the reported concentrations in the soil vapor samples are not
considered to pose a significant risk to future occupants through vapor intrusion due to the fine
grain soil types observed across the majority of the Project Site. No further action is
recommended with regard to vapor intrusion.
Nonetheless, in an abundance of caution, and because construction activities for the Project
would result in temporary ground-disturbing activities, the Project would implement MM HAZ-
1, which would require preparation of a Soil Management Plan (SMP) to address potential soils
with residual impacts remaining on the Project Site during future construction/redevelopment
activities. With implementation of MM HAZ-1, impacts would be reduced to less than significant.
Operation
Project operations are not expected to release any hazardous materials as a result of foreseeable
upset and accident conditions. The use and storage of such materials would be required to
continue to occur in compliance with applicable standards and regulations, and would not pose
significant hazards. It is anticipated that the use of such hazardous materials would not create a
significant hazard associated with a risk of upset or accident conditions involving the release of
hazardous materials during Project operations. A less than significant impact would occur in this
regard.
Mitigation Measure
MM HAZ-1 Soil Management Plan. Before the Building Official issues grading permits, a site-
specific Soil Management Plan (“SMP”) must be prepared by a qualified
environmental professional approved by the City and submitted to the City of
Rosemead Building and Safety Business Unit. The SMP must include the following
elements, as applicable:
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• Provisions for personal protection and monitoring exposure to construction
workers,
• Requirements for construction workers to be Hazardous Waste Operations
and Emergency Response (“HAZWOPER”) trained,
• Procedures to be undertaken in the event that contamination is identified
above action levels or previously unknown contamination is discovered,
• Procedures for the safe storage, stockpiling, and disposal of any impacted
soils,
• Emergency procedures and responsible personnel.
In the instance that previously unknown soil constituents are discovered during site excavation,
the contractor shall ensure that any soil contaminated beyond acceptable regulatory levels, shall
be contained, remediated if necessary, and disposed of pursuant to the performance standard
levels established by federal OSHA, Cal/OSHA, SCAQMD, RWQCB, and any other regulatory
agency with jurisdiction over CRECs or RECs on the Project Site.
4.9c 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 Project Site is 0.10 miles north of the University of the West.
Construction of the Project would involve the temporary use of hazardous substances in the form
of paint, adhesives, surface coatings and other finishing materials, and cleaning agents, fuels, and
oils typically used in construction. However, all such substances and materials would be used,
stored, and disposed of in accordance with applicable laws and regulations and manufacturers’
instructions and are not expected to cause risk to the public or nearby schools. In addition, all
construction work would be performed consistent with applicable federal OSHA Safety and
Health Standards and Cal/OSHA requirements to ensure the safety and well-being of construction
workers.
The types of potentially hazardous substances and materials that would be used during Project
operation would include those typical of residential developments, such as small quantities of
cleaning solvents, painting supplies, pesticides for landscaping, and pool maintenance. However,
such substances and materials would be contained, stored, and used in accordance with
manufacturers’ instructions and handled in compliance with applicable standards and
regulations. Therefore, construction and operation of the Project would not result in hazardous
emissions or handling of hazardous or acutely hazardous materials, substances, or waste that
would create a significant risk of exposure for the public or the environment, including schools.
Impacts would be less than significant.
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4.9d 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 refers to the Hazardous Waste
and Substances Site List, commonly known as the Cortese List, maintained by the DTSC. The
Cortese list contains hazardous waste and substance sites including public drinking water wells
with detectable levels of contamination, sites with known USTs having a reportable release, solid
waste disposal facilities from which there is a known migration, hazardous substance sites
selected for remedial action, historic Cortese sites, and sites with known toxic material identified
through the abandoned site assessment program. As indicated in the Phase I ESA, the Project Site
was listed in historical databases, such as the Historic Cortese, Cortese, Leaking Underground
Storage Tanks (LUST), and more. However, most cases that are listed in the database search are
designated as historical, no further action, no violations, or closed. The Project Site is also not
identified on a current (e.g., not historical) compiled hazardous materials site list pursuant to
California Government Code Section 65962.5.48 Therefore, impacts would be less than significant.
4.9e For a project located within an airport land use plan or, where such a plan has not been
adopted, within two miles of a public airport or public use airport, would the project
result in a safety hazard or excessive noise for people residing or working in the project
area?
No Impact. The Project Site is not located within or near an airport land use plan. The Project Site
is located approximately 3.3-miles to the southwest of the San Gabriel Valley Airport and is not
located within the airport’s influence area. Therefore, the Project would not result in an airport-
related safety hazard or excessive noise for people working in the Project area. No impact would
occur in this regard.
4.9f Would the project impair implementation of or physically interfere with an emergency
response plan or emergency evacuation plan?
Less Than Significant Impact. The Project Site is located in an established urban area that is well-
served by an existing roadway network. According to the Los Angeles County Department of
Public Works, SR 60, located approximately 0.54 miles south of the Project Site, is designated as
a freeway disaster route. Rosemead Boulevard, located approximately 1.04 miles east of the
Project Site, is designated as a disaster route.49 These disaster routes would not be subject to any
lane closures as a result of the Project. Construction activities, particularly those associated with
infrastructure improvements, may encroach adjacent roadways and may require temporary and
intermittent closure of the lane closest to the Project Site along Walnut Grove Avenue.
Nonetheless, while such closures may cause temporary inconvenience, they would not be
expected to substantially interfere with emergency response or evacuation plans, including the
48 California Department of Toxic Substances Control, Hazardous Waste and Substances Site List (Cortese),
https://www.envirostor.dtsc.ca.gov/public/search?cmd=search&reporttype=CORTESE&site_type=CSITES,FUDS&status=ACT,
BKLG,COM&reporttitle=HAZARDOUS+WASTE+AND+SUBSTANCES+SITE+LIST+%28CORTESE%29. Accessed October 29, 2025.
49 Los Angeles County Department of Public Works, City of Rosemead, 2008,
https://pw.lacounty.gov/dsg/disasterroutes/map/Rosemead.pdf. Accessed October 29, 2025.
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Los Angeles County Operational Area Emergency Operations Plan.50 Furthermore, the Project
would be designed according to applicable fire code standards and would provide adequate
circulation and access to facilitate emergency response. Project design and access would be
reviewed by LACFD to ensure that emergency access would be maintained. Therefore, the Project
would not conflict with the City’s adopted emergency response plan or emergency evacuation
plan, and impacts would be less than significant.
4.9g 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. The Project Site is in a fully urbanized area and it is not adjacent to any wildland.
Additionally, according to the California Department of Forestry and Fire Protection (CAL FIRE),
the Project Site is not within or near a State Responsibility Area (SRA) or a very high fire hazard
severity zone (VHFHSZ); see Section 4.20: Wildfire. Therefore, the Project would not expose
people or structures to a significant risk involving wildland fires. No impact would occur.
50 Los Angeles County, Operational Area Emergency Operations Plan, 2023, https://ceo.lacounty.gov/wp-
content/uploads/2023/11/County-of-Los-Angeles-OAEOP-2023-Final-for-Website.pdf. Accessed October 29, 2025.
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4.10 Hydrology and Water Quality
This Section is based on the Hydrology & Hydraulics Report (Hydrology Report) and the
Preliminary Low Impact Development (LID) Report, both prepared by Kimley-Horn and are
included in Appendix I: Hydrology & Hydraulics Report and Appendix J: Preliminary LID Report,
respectively.
Environmental Issue
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?
X
b) Substantially decrease groundwater supplies or
interfere substantially with groundwater recharge
such that the projects may impede sustainable
groundwater management of the basin?
X
c) Substantially alter the existing drainage pattern of
the site or area, including through the alteration of
the course of a stream or river or through the
addition of impervious surfaces, in a manner which
would:
(i) Result in substantial erosion or siltation on- or
off-site. X
(ii) Substantially increase the rate or amount of
surface runoff in a manner which would result
in flooding on- or off-site;
X
(iii) Create or contribute runoff water which
would exceed the capacity of existing or
planned stormwater drainage systems or
provide substantial additional sources of
polluted runoff; or
X
iv) Impede or redirect flood flows? X
d) In flood hazard, tsunami, or seiche zones, risk
release of pollutants due to project inundation? X
e) Conflict with or obstruct implementation of a water
quality control plan or sustainable groundwater
management plan?
X
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Impact Analysis
4.10a Would the project violate water quality or waste discharge requirements or otherwise
substantially degrade surface or groundwater quality?
Less Than Significant Impact.
Construction
The Project’s construction-related activities would include demolition, excavation, grading, and
trenching, which would displace soils and temporarily increase the potential for soils to be
subject to wind and water erosion and may allow eroded soils and other pollutants to enter the
storm drain system. Construction projects of one acre or more are regulated under the CGP,
Order No. 2022-0057-DWQ, issued by the SWRCB. Projects obtain coverage by developing and
implementing a SWPPP estimating sediment risk from construction activities to receiving waters
and specifying BMPs that would be used to minimize pollution of stormwater. The Project’s
construction contractor would be required to prepare and implement a SWPPP and associated
BMPs in compliance with the CGP during grading and construction activities. Typical construction
BMPs include, but are not limited to, watering soil, soil cover of inactive areas, gravel bags, and
fiber rolls. Project construction activities would also comply with the requirements of RMC
Chapter 13.16.030, Control of Urban Runoff, which requires stormwater and urban runoff
pollution prevention controls. Adherence to the BMPs in the SWPPP and requirements in the
MPMC would reduce, prevent, minimize, and/or treat pollutants and prevent degradation of
downstream receiving waters. BMPs identified in the SWPPP would reduce or avoid
contamination of stormwater with sediment and other pollutants such as trash and debris; oil,
grease, fuels, and other toxic chemicals; paint, concrete asphalt, etc.; and nutrients. Therefore,
water quality and waste discharge impacts from Project demolition, grading, and construction
activities would be less than significant.
Operation
Operation-related activities of the Project would generate pollutants that could adversely affect
the water quality of downstream receiving waters if effective measures are not used to keep
pollutants out of and remove pollutants from urban runoff. Requirements for waste discharges
to stormwater from operation of developed land uses within the coastal watersheds of Los
Angeles and Ventura Counties are in the Regional Phase I Municipal Separate Storm Sewer
System NPDES Permit (MS4 Permit), Order NO. R4-2021-0105, issued by the Los Angeles Regional
Water Quality Control Board (LARWQCB) in 2021. Los Angeles County has a LID Standards Manual
on developing water quality management plans for projects and selecting stormwater control
and source control BMPs in addition to other LID strategies. To meet the local MS4 permit and
LID requirements consistent with the County’s LID Ordinance and LID Standards Manual,
stormwater management strategies would be implemented throughout the Project Site.
According to the Geotechnical Investigation Report prepared for the Project, infiltration is not
considered geotechnically feasible and is therefore not recommended. The proposed LID BMP
system for the Project is a hydrodynamic separator unit for pre-treatment, Contech CMP
Detention System, and a Contech MWS-L-8-8-V MWS unit for biofiltration water quality
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treatment. The entire system operates via gravity flowing and ties into existing storm drain
infrastructure located in Walnut Grove Avenue at rates less than existing conditions. The Project
Site is split into two tributary areas, each with its own respective LID BMP system. Tributary area
A-1 has an 85th percentile design storm volume of 17,400 cubic feet. Tributary B-1 has an 85th
percentile design storm volume of 17,750 cubic feet. The Project will capture the required design
storm volumes based on the storage volume provided by the two Contech CMP Detention
System.
As the existing Project Site does not have any structural or LID BMPs on-site, implementation of
the proposed LID features would significantly improve surface water quality runoff compared to
existing conditions. Additionally, Project operation itself would not result in discharges that
would cause regulatory standards to be violated in the Los Angeles River Watershed. Therefore,
water quality and waste discharge impacts from Project operation would be less than significant.
4.10b Would the project substantially decrease groundwater supplies or interfere substantially
with groundwater recharge such that the project may impede sustainable groundwater
management of the basin?
Less Than Significant Impact.
The City overlies the Central Subbasin of the Los Angeles Coastal Plain Groundwater Basin. The
Central Basin is divided into three sections: the Los Angeles Forebay, the Montebello Forebay,
and the Whittier Area. The two forebays represent areas of unconfined aquifers that allow
percolation of surface water down into the deeper aquifers to replenish the basins. The Whittier
Area is a confined aquifer system that is replenished primarily from the upgradient forebays and
adjacent groundwater basins.
The Project would not include any groundwater pumping and would instead rely on the local
water purveyor for water. Additionally, no water supply wells are located at or within one
thousand feet of the Project Site. The Project would not include the construction of any water
supply wells, nor would the Project impact any existing water supply wells. Furthermore, as
stated in Response 4.7a.iii, groundwater was encountered in an exploratory boring performed
on-site at 40.8 bgs but was concluded that groundwater is not expected to pose a constraint
during construction of the Project. Dewatering is not anticipated for the Project and the Project
Site is also not within a groundwater recharge area or facility, nor does it represent a source of
groundwater recharge. Therefore, the Project would not substantially deplete groundwater
supplies nor interfere substantially with groundwater recharge such that the Project would
impede the basins’ sustainable groundwater management, and impacts would be less than
significant.
4.10c.i Would the project substantially alter the existing drainage pattern of the site or area,
including through the alterations of the course of stream or river or through the addition
of impervious surfaces, in a manner which would result in substantial erosion or siltation
on- or off-site?
Less Than Significant Impact. See Response 4.10a, above. The construction contractor would be
responsible for preparation and implementation of a SWPPP in compliance with LARWQCB’s CGP.
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This includes maintenance of BMPs during the life of the Project and submittal of the annual
reports.
Upon Project development, the Project would include LID biofiltration and detention BMPs in the
form of two Contech CMP Detention Systems that would accommodate an 85th percentile (0.9-
inch), 24-hour storm, consistent with the requirements of the MS4 Permit and LID Standards
Manual. Compliance with existing regulations and BMPs developed to minimize erosion and
siltation would reduce this impact to a less than significant level. The Project’s storm drain
collection and conveyance system would connect to the existing storm drain main line in Walnut
Grove Avenue, and no upgrades or expansion of such off-site facilities would occur with Project
implementation. Standard BMPs designed to prevent erosion during and after construction, as
well as the introduction of pervious land uses in the Project Site, would slow stormwater runoff
velocities and allow sediment to settle out of the water, and the nature of drainage patterns on
the Project Site would capture trash and debris and restrict flow of debris into the storm drain
system. Water runoff would be minimized to the extent possible, and the Project would comply
with the requirements of the MS4 Permit. The Project would be designed to meet local, State,
and federal water quality standards and to ensure that stormwater flows do not result in
substantial erosion or siltation.
Therefore, post-development runoff would be adequately handled by the Project’s detention
BMPs and would not exceed the capacity of existing or planned stormwater drainage systems or
substantially alter the existing drainage pattern of the Project Site or area in a manner that would
result in flooding on- or off-site. Therefore, Project impacts would be less than significant.
4.10c.ii Would the project substantially alter the existing drainage pattern of the site or area,
including through the alterations of the course of stream or river or through the addition
of impervious surfaces, in a manner which would substantially increase the rate or
amount of surface runoff in a manner which would result in flooding on- or off-site?
Less Than Significant Impact. See Response 4.10.a and 4.10c.i, above.
Project development would decrease the amount of impervious surfaces on the Project Site from
approximately 100 percent (9.28 acres) to 84.9 percent (7.88 acres). On-site runoff from the
Project Site would be collected in the two Contech CMP Detention System, which would
accommodate an 85th percentile (0.9-inch), 24-hour storm. The Project Site is split into two
tributary areas, each with its own respective LID BMP system. Tributary area A-1 has an 85th
percentile design storm volume of 17,400 cubic feet. Tributary B-1 has an 85th percentile design
storm volume of 17,750 cubic feet. The Project will capture the required design storm volumes
based on the storage volume provided by the two Contech CMP Detention System. The storage
volume for Tributary Area A-1 would be 17,558 cubic feet, and the storage volume for Tributary
Area B-1 would be 17,785 cubic feet. Accordingly, the Project would not result in on- or off-site
flooding.
Therefore, post-development runoff would be adequately handled by the Project’s drainage
system and would not exceed the capacity of existing or planned stormwater drainage systems
or substantially alter the existing drainage pattern of the Project Site or area in a manner that
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would result in flooding on- or off-site, and impacts would be less than significant.
4.10c.iii Would the project substantially alter the existing drainage pattern of the site or area,
including through the alterations of the course of stream or river or through the addition
of impervious surfaces, in a manner which would create or contribute runoff water which
would exceed the capacity of existing or planned stormwater drainage systems or
provide substantial additional sources of polluted runoff?
Less Than Significant Impact. As described above in Responses 4.10a and 4.10c.i, Project impacts
on the capacity of storm drainage systems and stormwater pollution would be less than
significant.
4.10c.iv Would the project substantially alter the existing drainage pattern of the site or area,
including through the alterations of the course of stream or river or through the addition
of impervious surfaces, in a manner which would impede or redirect flood flows?
Less Than Significant Impact. The Project Site is located within a flood hazard area identified by
the Federal Emergency Management Agency (FEMA) as Zone X51, which is defined as an area
outside of the 0.2 percent (500-year) annual chance floodplain. However, the Project Site is
located within the dam inundation area of the Garvey Reservoir. The Garvey Reservoir is a
reservoir located approximately 0.2-mile west of the Project Site that is impounded by three
embankment dams.
Garvey Reservoir is classified by the State Department of Water Resources, Division of Safety of
Dams (DSOD) as an extremely high downstream hazard. However, as of September 2023, the
dam was given a Satisfactory Condition Assessment by the DSOD, and no existing or potential
dam safety deficiencies were recognized.52 Acceptable performance is expected under all types
of loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable
State or federal regulatory criteria or tolerable risk guidelines. FEMA requires that all dam owners
develop Emergency Action Plans (EAPs) for warning, evacuation, and post-flood actions. An EAP
identifies potential emergency conditions at a dam and specifies actions to be followed to help
minimize loss of life and property damage should those conditions occur. EAPs include
procedures dam owners will follow to issue early warning and notification messages to
responsible downstream emergency management authorities. EAPs also include inundation
maps to help dam owners and emergency management authorities identify critical infrastructure
and population-at-risk sites that may require protective measures, warning, and evacuation
planning. Thus, the potential for dam flooding at the Project Site is considered low. Additionally,
as discussed in greater detail above under Response 4.10c.ii, the Project’s drainage system would
adequately handle post-development runoff and would not substantially alter the existing
51 FEMA, National Flood Hazard Layer FIRMette,
https://msc.fema.gov/arcgis/rest/directories/arcgisjobs/nfhl_print/mscprintb_gpserver/j7daf81b291f44d2d819d2ad6617c06
2c/scratch/FIRMETTE_d0dcd241-c53b-4687-be1e-a0001526e08e.pdf. Accessed September 26, 2025.
52 California Department of Water Resources, Division of Safety of Dams. Dams Within Jurisdiction of the State of California,
2023, page 36, https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/All-Programs/Division-of-Safety-of-
Dams/Files/Publications/DAMS-WITHIN-JURISDICTION-OF-THE-STATE-OF-CALIFORNIA-LISTED-ALPHABETICALLY-BY-DAM-
NAME-SEPTEMBER-2023.pdf. Accessed September 26, 2025.
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drainage pattern of the Project Site or area that would result in flooding on- or off-site. Therefore,
the Project would not impede or redirect flood flows, and impacts would be less than significant.
4.10d Would the project in flood hazard, tsunami, or seiche zones, risk release of pollutants
due to project inundation?
Less Than Significant Impact. As noted in Response 4.10c.iv, the Project Site is in an area of
minimal flood hazard. Although the Project Site is within the dam inundation area of the Garvey
Reservoir, as of September 2023, no existing or potential dam safety deficiencies were
recognized, and acceptable performance is expected under all types of loading conditions. Thus,
the potential for dam flooding at the Project Site is considered low.
Tsunamis are sea waves that are generated in response to large-magnitude earthquakes. When
these waves reach shorelines, they sometimes produce coastal flooding. Seiches are large waves
generated in enclosed bodies of water in response to ground shaking. The Project Site is located
approximately 22 miles inland from Pacific Ocean, and there are no nearby bodies of standing
water. Tsunamis and seiches do not pose hazards due to the Project site’s inland location and
lack of nearby bodies of standing water. The Project is not within a flood hazard, tsunami, or
seiche zone and, thus, potential impacts associated with inundation by flood hazard, tsunami, or
seiche would be less than significant.
4.10e Would the project conflict with or obstruct implementation of a water quality control
plan or sustainable groundwater management plan?
Less Than Significant Impact. As substantiated in Response 4.10a, through compliance with
pertinent existing laws and regulations, the Project would not violate any water quality standards
and therefore would not obstruct the implementation of a water quality control plan.
The Project Site is in the San Gabriel Valley Groundwater Basin, which is identified by the
Sustainable Groundwater Management Act (SGMA) as a very low priority basin.53 The SGMA
requires only medium- and high-priority basins to form groundwater sustainability agencies,
develop groundwater sustainability plans, and manage groundwater for long-term sustainability.
Therefore, the San Gabriel Valley Groundwater Basin does not require a sustainable groundwater
management plan. Additionally, as further detailed in Response 4.10b, the Project would not
decrease groundwater supplies or interfere substantially with groundwater recharge. Therefore,
impacts would be less than significant.
53 California Department of Water Resources, SGMA Basin Prioritization Dashboard, https://gis.water.ca.gov/app/bp-
dashboard/final/. Accessed September 25, 2025.
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4.11 Land Use and Planning
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Physically divide an established community? X
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?
X
Impact Analysis
4.11a Would the project physically divide an established community?
No Impact. The Project Site is developed with two vacant buildings and associated parking. The
Project proposes new residential uses, open space and amenities, and an interior pedestrian and
vehicle circulation system. No physical barriers which could physically divide an established
community are proposed. Although established residential neighborhoods lie to the west of the
Project Site, Project development would not physically divide these neighborhoods in any way
because the Project would be developed within the Project Site, and all off-site infrastructure
improvements would not transect those neighborhoods. Access to the existing residential
neighborhoods would not be impeded or cut off as a result of Project development. Therefore,
the Project would not physically divide an established community. No impact would occur in this
regard.
4.11b 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 Project Site has a General Plan land use designation of
Office/Light Industrial. The primary uses allowed within the General Plan land use designation
include commercial development and light industrial uses. The Project proposes a General Plan
Amendment to change the existing land use from Office/Light Industrial to High Density
Residential. The High Density Residential use allows many forms of attached housing: triplexes,
fourplexes, apartments, and condominiums/townhouses, and small lot or clustered detached
units. The maximum permitted density is 30 units per acre.54
General Plan Vision
With the General Plan, the City seeks to achieve the following vision:
54 City of Rosemead, 2021-2029 Housing Element, 2022, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/Adopted%20Rosemead%202021-2029%20Housing%20Element_CERTIFIED%20080122.pdf.
Accessed August 6, 2025.
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• Enhance the commercial areas along key corridors, and most specifically Garvey Avenue
and Valley Boulevard;
• Create an economically viable downtown that blends retail, office, and residential uses in
a walkable, attractive setting;
• Enhance parks and recreational space in underserved neighborhoods;
• Accommodate the demand for quality mixed-use development that can contribute to
commercial growth and enhance opportunities for higher-density residential
development;
• Protect homeowner investments and the availability of well-maintained, relatively
affordable housing units;
• Minimize the impact of traffic associated with growth within the San Gabriel Valley and
broader region.
General Plan Land Use Element
The Land Use Element of the General Plan sets forth policies for guiding development, including
residential development, in the City. These policies establish the quantity and distribution of land
allocated for future development and redevelopment in the City.
Goal 1: Maintain stable and attractive single family residential neighborhoods.
Policy 1.1: Discourage the entitlement and construction of multiple-family units in
neighborhoods that are predominately single-family.
Policy 1.2: Provide guidelines and standards to ensure adequate buffering and screening
between lower density residential uses and adjacent higher density residential or
nonresidential uses to mitigate potential land use conflicts.
The Project would be consistent with the above General Plan Visions and the Land Use Element
goals and policies as the Project would provide new housing on an infill site, near existing
development, transit, and road access. The Project would not infringe on existing single-family
residential development as it would be developed to the east of an existing neighborhood but
between developed commercial and institutional areas to the north and the south. The Project
would include market rate housing units in a variety of sizes and styles, supporting a range of
housing choices in the City for various household types and income levels.
The Project’s design, massing, and height are designed to be compatible with the neighboring
commercial and residential uses while also providing a new high-quality community with a
distinctive architecture aesthetic. Furthermore, the Project would include landscaping on all ends
of the Project Site and throughout the Project Site. A landscape buffer would be provided along
the Project perimeter to provide a physical and visual buffer from surrounding uses. The Project’s
landscaping would include native trees, shrubs, and groundcover, all of which would have very
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low or low water needs. The Project’s proposed landscaping would comply with the City’s design
requirements.
The Project proposes a General Plan Amendment to change the existing land use from
Office/Light Industrial to High Density Residential. This land use amendment would allow the
Project Site to be redeveloped with a viable and desirable use consistent with surrounding land
uses and the goals and policies of the General Plan. Therefore, the Project would not conflict with
the any of the City’s land use plan, policies, or regulations that have been adopted for the purpose
of avoiding or mitigating an environmental effect, and no land use conflict related to General
Plan consistency is expected to occur.
Housing Element
The State’s Housing Element law requires local governments to make plans to adequately address
their share of existing and projected population growth, taking into consideration affordability of
available and future housing. Recognizing that the most critical decisions regarding housing
development occur at the local level, through a City’s General Plan, the Housing law seeks to
adequately address housing needs and demands. The California HCD enforces State Housing
Element Law by requiring certified Housing Elements as part of every City’s General Plan. The City
of Rosemead 2021-2029 Housing Element was adopted by City Council on January 11, 2022, and
approved by the State HCD on August 1, 2022. For the 2021-2029 Housing Element, the City is
allocated a Regional Housing Needs Assessment (RHNA) of 4,612 units. Approximately 38.8
percent of these units should accommodate very-low- and low-income households.
This Housing Element identifies housing strategies and programs that focus on:
1. Conserving and improving existing affordable housing;
2. Providing adequate housing sites;
3. Assisting in the development of affordable housing;
4. Removing governmental constraints to the development of housing; and
5. Promoting equal housing opportunities
The following applicable goals and policies included in the Housing Element are listed below:
Goal 1: Protect existing stable, single-family neighborhoods throughout the City.
Policy: Encourage the construction of new single-family attached and detached
dwellings using zoning and other mechanisms.
Policy: Preserve existing residential areas by using design measures to buffer these
sensitive land uses from adjacent dissimilar uses.
Goal 2: Encourage the development of a range of housing types in a range of prices affordable to
all Rosemead residents.
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Policy: There shall be a variety of housing types and prices to accommodate a wide range
of housing needs and tastes.
Policy: Encourage housing opportunities within the mixed-use residential/commercial
overlay districts to provide needed infill development opportunities.
The Project would redevelop the Project Site with a residential development that would increase
the housing stock in the City with 191 new residential units including tandem townhomes and
row townhomes. The mixture of different unit types would contribute to the range of housing
choices in the City. Furthermore, the Project would include landscaping on all ends of the Project
Site and throughout the Project Site. A landscape buffer would be provided along the Project
perimeter to provide a physical and visual buffer from surrounding uses. The Project’s
landscaping would include native trees, shrubs, and groundcover, all of which would have very
low or low water needs. Thus, the Project would support the City’s Housing Element goals and
policies and would assist the City in meeting its RHNA allocations by contributing to the overall
supply of housing without removing any existing housing to do so. Furthermore, the Project
would provide these new units by redeveloping an urban infill site that is close to existing utilities,
roadways, and transit options that serve the Project Site and the greater region. Therefore, the
Project would be substantially consistent with the City’s General Plan Housing Element.
Zoning
The Project Site is located within the C-3 Zone with a D-O. The Project proposes a Zoning
Amendment to change the existing zone from C-3 and D-O to P-D. According to the RMC, the PD
Zone allows all land use designations in the RMC, except for high intensity commercial, open
space, and cemeteries. The P-D Zone is intended to provide for residential, commercial,
industrial, or institutional developments that are characterized by innovative use and design
concepts.
Multi-family dwellings units such as those proposed by the Project are permitted in the P-D Zone.
Projects developed in the P-D Zone are designed to be approved under a precise plan, and the
zone provides new development to offer amenities, quality, design excellence, and other similar
benefits to the community.55 Per the requirements of the P-D Zone the Project would be a high-
quality residential community, with distinctive architecture, signage, ample amenities, and open
space. The Project’s Zoning Amendment from C-3 and D-O to P-D would enable the development
of a new well-designed infill residential community near transit and other infrastructure
consistent with good planning practices and help meet the housing needs of the City. Therefore,
with the proposed Zoning Amendment, no land use conflict related to zoning consistency would
occur.
55 City of Rosemead, Rosemead Municipal Code Title 17 Zoning, Chapter 17.24 Special Purpose Zoning Districts.
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4.12 Mineral Resources
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Result in the loss of availability of a known mineral
resource that would be of value to the region and the
residents of the state?
X
b) Result in the loss of availability of a locally-important
mineral resource recovery site delineated on a local
general plan, specific plan, or other land use plan?
X
Impact Analysis
4.12a Would the project result in the loss of availability of a known mineral resource that
would be of value to the region and the residents of the state?
4.12b Would the project result in the loss of availability of a locally-important mineral resource
recovery site delineated on a local general plan, specific plan, or other land use plan?
No Impact. According to the California Geological Survey, the Project Site is within the San Gabriel
Production-Consumption Region. The Project Site is within Mineral Resource Zone (MRZ)-3.56 As
stated in the Resources Management Element, the significance of mineral deposits in MRZ-3
cannot be determined from the available data; as the City is urbanized, and the State has not
identified any significant recoverable mineral resources, no mineral extraction activities are
permitted within the City limits. Therefore, mining would not be feasible, and the City is not
considered to be a potential future source for mineral resources. Additionally, the Project Site
and immediate vicinity currently do not contain any active mining or drilling operations.57,58
Therefore, the Project would not result in the loss of availability of a known mineral resource or
a locally-important mineral resource recovery site. No impact would occur.
56 City of Rosemead, Resources Management Element, Figure 4-2, June 2008, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Rosemead.pdf. Accessed August 6, 2025.
57 DOC, Well Finder, https://maps.conservation.ca.gov/doggr/wellfinder/. Accessed August 6, 2025.
58 DOC, Mines Online, 2016, https://maps.conservation.ca.gov/mol/index.html. Accessed August 6, 2025.
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4.13 Noise
This Section is based on the Noise and Vibration Analysis Technical Memorandum prepared by
Kimley-Horn, which is included in Appendix K: Noise and Vibration Analysis Technical
Memorandum.
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Generate a substantial temporary or permanent
increase in ambient noise levels in the vicinity of
the project in excess of standards established in the
local general plan or noise ordinance, or applicable
standards of other agencies?
X
b) Generate of excessive ground borne vibration or
groundborne noise levels?X
c) For a project located within the vicinity of a private
airstrip or an airport land use plan or, where such a
plan has not been adopted, within two miles of a
public airport or public use airport, would the
project expose people residing or working in the
project area to excessive noise levels?
X
Regulatory Setting
City of Rosemead Municipal Code
The City has adopted regulations to control unnecessary, excessive, and annoying noise and
establish acceptable ambient sound levels, as set forth in the City Noise Ordinance (Chapter 8.36
of the RMC).
Section 8.36.030 - Exemptions
Noise sources associated with construction or grading of any real property, provided such activiti,
es do not take place between the hours of eight p.m. and seven a.m. on weekdays, including
Saturday, or at any time on Sunday or a federal holiday, and provided the noise level created by
such activities does not exceed the noise standard of sixty-five (65) dBA plus the limits specified
in Section 8.36.060(B) as measured on residential property and does not endanger the public
health, welfare and safety is exempt from the provisions in the chapter.
Section 8.36.060 - Noise Standards
1. The following noise standards shown in Table 4.13-1: City of Rosemead Noise Standards,
unless otherwise specifically indicated, shall apply to all receptor properties within a
designated noise zone:
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Table 4.13-1: City of Rosemead Noise Standards
Zone Type of Land Use (Receptor
Property) Time Interval Allowable Exterior
Noise Level (dBA)
I Single-, double- or multiple-
family residential
10:00 p.m. - 7:00 a.m. 45
7:00 a.m. - 10:00 p.m. 60
II Commercial 10:00 p.m. - 7:00 a.m. 60
7:00 a.m. - 10:00 p.m. 65
III Industrial or Manufacturing Anytime 70
Source: City of Rosemead, RMC, Section 8.36.060 – Noise Standards,
https://library.municode.com/ca/rosemead/codes/code_of_ordinances?nodeId=CD_ORD_TIT8HESA_CH8.36NOCO_8.36.06
0NOST. Accessed September 25, 2025.
2. A person shall not create any noise, or allow the creation of any noise on property owned,
leased, occupied or otherwise controlled by such person (hereinafter "noise source"), which
causes the noise level when measured on any property (hereinafter "receptor property"), to
exceed:
a. The applicable noise standard for a cumulative period of time of more than thirty (30)
minutes in any hour; or
b. The applicable noise standard plus five dBA for a cumulative period of more than fifteen
(15) minutes in any hour; or
c. The applicable noise standard plus ten dBA for a cumulative period of more than five
minutes in any hour; or
d. The applicable noise standard plus fifteen (15) dBA for a cumulative period of more than
one minute in any hour; or
e. The noise standard plus twenty (20) dBA for any period of time.
3. If the ambient noise level exceeds any of the first three noise limit categories above, the
cumulative period applicable to said category shall be increased to reflect ambient noise level.
If the ambient noise level exceeds the third noise limit category, the maximum allowable noise
level under said category shall be increased to reflect the maximum ambient noise level.
5. If the noise source is continuous and cannot reasonably be discontinued or stopped for a time
period whereby the ambient noise level can be determined, the measured noise level
obtained while the source is in operation shall be compared directly to the receptor property's
designated land use and for the time of day the noise level is measured.
Section 8.36.100 - Specific Prohibitions
The following acts, and the causing thereof, are declared to be in violation of this chapter.
A. Radios, Television Sets, Musical Instruments and Similar Devices. Operating, playing or
permitting the operation or playing of any radio, television, phonograph, drum, musical
instrument, sound amplifier, or similar device which produces, reproduces, or amplifies sound
between the hours of ten p.m. and seven a.m. the following day in such a manner as to create
a noise disturbance across a real property boundary or within a noise sensitive zone.
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B. Loudspeakers/Public Address Systems.
a. Using or operating for noncommercial purpose any loudspeaker, public address system,
or similar device between the hours of ten p.m. and seven a.m. the following day, such
that the sound therefrom creates a noise disturbance across a residential real property
boundary.
C. Loading and Unloading. Loading, unloading, opening, closing or other handling of boxes,
crates, containers, building materials, garbage cans, or similar objects between the hours of
ten p.m. and six a.m. the following day in such a manner as to cause a noise disturbance across
a residential real property boundary.
Existing Conditions
Existing Noise Sources
The Project Site is located within an urban environment and impacted by various noise sources.
Mobile noise sources, especially traffic traveling along Walnut Grove Avenue, are the most
common and substantial noise sources within the Project vicinity. The primary stationary noise
sources near the Project Site are those associated with the surrounding commercial, institutional,
recreational, and residential uses. Such stationary noise sources include mechanical equipment
(e.g., heating, ventilation, and air conditioning [HVAC] equipment), idling and moving vehicles,
parking lot activities, car radios and music playing, truck deliveries, dogs barking, people talking,
recreational golf activities, and landscaping equipment. The noise associated with these sources
may represent a single-event noise occurrence or short-term noise.
Noise Measurements
To quantify existing ambient noise levels in the Project vicinity, Kimley-Horn conducted four
short-term (10-minutes) noise measurements between 12:40 p.m. and 1:40 p.m. on August 6,
2025; see Appendix K for additional details regarding how the ambient noise measurements
were taken. The noise measurement sites were selected to be representative of the existing
ambient noise levels at the noise-sensitive uses adjacent to the Project Site. Measurements of
Leq are considered representative of the noise levels throughout the day. The average noise levels
measured at each location are listed in Table 4.13-2: Existing Noise Measurements and shown
on Figure 4.13-1: Noise Monitoring Location Map.
SR-1
SR-1
SR-2
SR-4
SR-3
ST-#
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Table 4.13-2: Existing Noise Measurements
Site Location Measurement
Period Duration Daytime Average
(dBA Leq)
ST-1 Northeast corner of the Project Site,
along Walnut Grove Avenue
12:40 p.m. -
12:50 p.m. 10 minutes 68.8
ST-2 University of the West parking lot,
adjacent to the south of the Project Site
12:55 p.m. –
1:05 p.m. 10 minutes 53.7
ST-3 Northwest corner of Drayer Lane and
Walnut Grove Avenue
1:11 p.m. –
1:21 p.m. 10 minutes 67.4
ST-4 Cult-a-sac along Yarrow Street, adjacent
to the west of the Project Site
1:30 p.m. –
1:40 p.m. 10 minutes 44.5
ST = short-term noise measurement
Source: Noise measurements taken by Kimley-Horn and Associates, Inc., August 6, 2025. See Appendix K for the noise
measurement results.
Sensitive Receptors
Noise exposure standards and guidelines for various types of land uses reflect the varying noise
sensitivities associated with each of these uses. The City of Rosemead General Plan defines
sensitive receptors as residential uses, schools, libraries, offices, hospitals, churches, hotels,
motels and outdoor recreational areas.59 The sensitive receptors nearest the Project Site are
listed in Table 4.13-3: Sensitive Receptors and shown on Figure 4.13-2: Sensitive Receptor
Locations Map.
Table 4.13-3: Sensitive Receptors
Receptor Description Distance1 and Direction from the
Project Site
Sensitive Receptor 1 – University of the West Adjacent to the south
Sensitive Receptor 2 – Residential Uses 653 feet to the south
Sensitive Receptor 3 – Residential Uses Adjacent to the west
Sensitive Receptor 4 – Whittier Narrows Golf
Course 80 feet to the east
Sensitive Receptor 5 – Residential Uses 432 feet to the southeast
1. Distance measured from the Project Site property line to the nearest sensitive receptor property line.
Source: Google Earth Pro, 2025.
59 City of Rosemead, City of Rosemead General Plan Update, 2010, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Planning/Rosemead.
pdf. Accessed September 19, 2025.
SR-1
SR-#
SR-1
SR-2
SR-3
SR-4
SR-5
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Thresholds
The Project is located within the City of Rosemead and as such, the noise and vibration impact
analysis herein compares Project impacts at all identified receptors against the City’s standards.
Construction Noise
Pursuant to the City Noise Ordinance, construction between the hours of 10:00 p.m. and 7:00
a.m. Monday through Saturday, or at any time on weekends and nationally recognized holidays
and that exceeds 65 dBA plus the limits specified in RMC Section 8.36.060(B) is prohibited.
Therefore, this analysis uses the City’s threshold of 65 dBA for residential receptors to evaluate
construction noise impacts at residential and institutional receptors.
Operational Noise – Off-Site Traffic Noise
Because a doubling of traffic is considered to cause a perceptible noise increase of 3-dBA above
existing noise conditions, the significance for the off-site traffic noise is assessed based on a
doubling of existing traffic conditions.60
Operational Noise – On-Site Stationary Noise Operational noise impacts on the institutional and
residential receptors are evaluated based on the standards within the City Noise Ordinance. A
composite operational stationary noise impact would occur if the City’s daytime noise standard
of 60 dBA and the substantial increase threshold of 5 dBA are exceeded or the City’s nighttime
noise standard of 45dBA is exceeded.
Vibration
The City has not established a quantitative vibration threshold. Therefore, this analysis uses the
vibration thresholds provided by the FTA’s Transit Noise and Vibration Assessment Manual for
building damage and Caltrans’ Transportation and Construction Vibration Manual for human
annoyance. Based on the FTA criteria, construction vibration impacts would be significant if
vibration levels exceed 0.3 inches-per-second (in/sec) peak particle velocity (PPV) for engineered
concrete and masonry buildings. Based on the Caltrans’ criteria, construction vibration impacts
with regards to human annoyance would be significant if vibration levels exceed the Caltrans’
threshold of 0.2 in/sec PPV at the nearest structure.
Impact Analysis
4.13a Would the project result in generation a substantial temporary or permanent increase
in ambient noise levels in the vicinity of the project in excess of standards established in
the local general plan or noise ordinance, or applicable standards of other agencies?
Less Than Significant Impact With Mitigation Incorporated.
Construction Noise
Construction noise typically occurs intermittently and varies depending on the nature or phase
of construction (e.g., land clearing, grading, excavation, paving). Noise generated by construction
equipment, including earth movers, material handlers, and portable generators, can reach high
60 California Department of Transportation, Technical Noise Supplement to the Traffic Noise Analysis Protocol, 2017.
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levels. During construction, exterior noise levels could affect the commercial and industrial
receptors near the construction site.
Project construction activities would include demolition, site preparation, grading, infrastructure
improvements, building construction, paving, and architectural coating applications, as well as
off-site improvements (i.e., sidewalk improvements and grind and overlay of Walnut Grove
Avenue along the Project Site frontage). Typical operating cycles for these types of construction
equipment may involve 1 or 2 minutes of full power operation followed by 3 to 4 minutes at
lower power settings. Other primary sources of acoustical disturbance would be random
incidents, which would last less than one minute (such as dropping large pieces of equipment or
the hydraulic movement of machinery lifts).
Typical noise levels associated with individual construction equipment are listed in Table 4.13-4:
Typical Construction Noise Levels . It should be noted that the noise level values shown in Table
4.13-4: Typical Construction Noise Levels are for the equipment when operating at full power 50
feet from the sensitive receptor, without taking into account any intervening structures or
topography that may reduce noise levels.
Table 4.13-4: Typical Construction Noise Levels
Equipment Typical Noise Level (dBA) at 50 feet from Source
Air Compressor 80
Backhoe 80
Compactor 82
Concrete Mixer 85
Concrete Pump 82
Concrete Vibrator 76
Crane, Mobile 83
Dozer 85
Generator 82
Grader 85
Impact Wrench 85
Jack Hammer 88
Loader 80
Paver 85
Pneumatic Tool 85
Pump 77
Roller 85
Saw 76
Scraper 85
Shovel 82
Truck 84
Source: Federal Transit Administration. (2018). Transit Noise and Vibration Impact Assessment Manual.
The FHWA’s RCNM was used to calculate construction noise at 50 feet for each of the Project
construction phases. The highest calculated noise level at 50 feet would occur during the overlap
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of building construction, paving, and architectural coating. Construction noise was calculated
accounting for each piece of equipment’s usage factor, or the fraction of time that the equipment
would be in use at full power over a specific period of time, based on Table 1 of RCNM.61
Construction noise during the overlap of building construction, paving, and architectural coating
at neighboring sensitive uses has been calculated using SoundPLAN. As this is the period of
construction that would result in the greater noise level, all other construction phases would
result in lower noise levels.
Noise levels were based on the equipment used, distance to the nearest receptor, and acoustical
usage factor for equipment. The noise from each piece of construction equipment was modeled
as an area source across the entire Project Site. This methodology accounts for equipment
operating throughout the Project Site and not at a fixed location for extended periods of time.
See Appendix K for more information regarding the construction assumptions used in this
analysis.
Table 4.13-5: Project Maximum Construction Noise Levels summarizes the exterior construction
noise attributable to the Project. Implementation of MM NOI-1 and MM NOI-2, provided below,
would reduce the Project’s construction noise levels. Specifically, MM NOI-1 requires the proper
maintenance of construction equipment and the installation of noise shielding/muffling devices.
The FHWA states that muffler systems can reduce noise levels by 10 dBA or more.62 MM NOI-2
requires the use of temporary noise barriers such as plywood walls with a minimum ½-inch
thickness or sound blankets meeting a sound transmission class (STC) rating of 25 located along
the western boundary of the Project Site. Sound blankets meeting a STC 25 rating can achieve a
minimum seven to 10 dBA reduction for construction equipment with 200 Hz or lower
frequency.63 A reduction of 10 dBA has been applied to the sound power levels for applicable
pieces of construction equipment in SoundPLAN, accounting for the use of noise muffling devices
required by MM NOI-1, and an eight-foot tall solid barrier, as required by MM NOI-2, along the
western boundary of the Project Site has been input into the SoundPLAN model. As shown in
Table 4.13-5, on-site construction noise with implementation of mitigation would not exceed the
applicable thresholds. Therefore, construction noise impacts associated with on-site sources
would be less than significant with mitigation incorporated.
Table 4.13-5: Project Maximum Construction Noise Levels
Receptor
Maximum
Noise Level at
Receptor Prior
to MMs (Leq) 1
Maximum
Noise Level
at Receptor
with MMs
(Leq) 1, 2
City
Noise
Threshold
(dBA Leq) Exceeded?
1 – University of the
West
Floor 1
Floor 2
65.4
66.5
56.5
57.5
65 No
61 California Department of Transportation, Technical Noise Supplement to the Traffic Noise Analysis Protocol, 2017.
62 Federal Highway Administration, Special Report - Measurement, Prediction, and Mitigation, Chapter 4 Mitigation, 2017.
63 Environmental Noise Control, Portable Acoustic Panels, 2024, https://environmental-noise-control.com/products/temporary-sound-walls/.
Accessed September 19, 2025.
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Table 4.13-5: Project Maximum Construction Noise Levels
Receptor
Maximum
Noise Level at
Receptor Prior
to MMs (Leq) 1
Maximum
Noise Level
at Receptor
with MMs
(Leq) 1, 2
City
Noise
Threshold
(dBA Leq) Exceeded?
2 – Residential
Floor 1
48.0
38.9 65 No
3 – Residential
Floor 1
Floor 2
68.4
63.7
53.7
53.6
65 No
4 – Whittier Narrows
Golf Course 63.5 54.5 65 No
5 – Residential
Floor 1
Floor 2
55.6
55.7
46.6
46.7
65 No
1. Construction equipment noise has been modeled as area sources covering the entire Project Site.
2. Assumes noise level reductions provided by MM MOI-1 (Mufflers) and MM NOI-2 (Temporary Barriers).
Source: Refer to Appendix K for noise modeling results.
As depicted in Table 4.13-5, Project construction noise would not exceed the City threshold of 65
dBA Leq at any of the identified receptors with mitigation incorporated. Additionally, the Project
would comply with the City’s allowable hours of construction, which are required in recognition
that construction activities undertaken during daytime hours are a typical part of living in an
urban environment and do not cause a significant impact.
Construction-related noise would be temporary and would not result in a permanent increase in
ambient noise levels in the area. Additionally, construction activities would be prohibited
between the hours of between the hours of 10:00 p.m. and 7:00 a.m. Monday through Saturday,
or at any time on weekends and nationally recognized holidays. The City’s permitted hours of
construction are required in recognition that construction activities undertaken during daytime
hours are a typical part of living in an urban environment and do not cause a significant impact.
Therefore, impacts in regard to on-site construction noise would be less than significant.
Off-Site Mobile Construction Noise
In addition to on-site construction noise, the Project would generate mobile-source noise from
delivery/haul trucks and construction workers traveling to and from the Project Site during
Project construction via Walnut Grove Avenue. Project construction-generated trips would be
temporary and cease with the end of construction.
Traffic volumes along roadways within the Project vicinity would have to approximately double
for the resulting traffic noise levels to generate a barely perceptible 3‐dBA increase.64 According
to average daily traffic (ADT) data provided by Replica HQ, Walnut Grove Avenue between Rush
64 According to the California Department of Transportation, Technical Noise Supplement to Traffic Noise Analysis Protocol, 2013, it takes a
doubling of traffic to create a noticeable (i.e., 3-dBA) noise increase.
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Street and Drayer Lane has an ADT of 9,055.65 According to modeling assumptions in the air
quality analysis prepared by Kimley-Horn in October 2025, the construction phase with the
highest assumed number of vehicles would be building construction, when it is assumed, there
would be up to 21 daily vendor truck trips and 139 daily worker (passenger vehicle) trips accessing
the Project Site. As Project construction would not double the existing traffic volumes on Walnut
Grove Avenue, the proposed Project would not generate enough traffic to result in a noticeable
3-dBA increase in ambient noise levels. Impacts associated with off-site construction mobile
noise would be less than significant, and no mitigation is required.
Operational Noise
The major on-site noise sources associated with the Project operations would include mechanical
equipment (e.g., HVAC equipment), trash and recycling collection, parking and access noise, dog
park, outdoor recreational space, pool equipment, and a water pump station.
Mechanical Equipment
Potential stationary noise sources related to long-term Project operations would include
residential mechanical equipment (e.g., HVAC equipment). A household air conditioning unit
typically generates noise levels of approximately 52 dBA at 50 feet.66 It is conservatively assumed
the nearest mechanical equipment (e.g., air conditioning unit) would be located on the side
nearest the sensitive receptor. The noise levels associated with the mechanical equipment at the
nearest sensitive receptors are shown in Table 4.13-6: Mechanical Equipment Noise Levels .
Table 4.13-6: Mechanical Equipment Noise Levels
Receptor
Distance
to
Receptor
(feet)1
Modeled
Noise Level
at
Receptor
(dBA)
Daytime
Noise
Standard
(dBA) 2
Standard
Exceeded
?
Nighttime
Noise
Standard
(dBA) 2
Standard
Exceeded
?
1 – University of the West
(south) 97 46.2 65 No 55 No
2 – Residential Uses
(south) 700 29.1 60 No 45 No
3 – Residential Uses (west) 15 52.53 60 No 45 Yes
4- Whitter Narrows Golf
Course (east) 102 45.8 60 No N/A4 No
5 – Residential Uses
(southeast) 580 30.7 60 No 45 No
1. Distance from the nearest townhouse to the nearest sensitive receptors.
2. Pursuant to City Noise Ordinance the residential daytime threshold is 60 dBA, the residential nighttime threshold is 45 dBA, the
commercial daytime noise threshold is 65 dBA, and the nighttime commercial threshold is 60 dBA.
65 ReplicaHQ, Replica Annual Average Daily Traffic (AADT) Data, https://www.replicahq.com/aadt. Accessed September 16, 2025.
66 Elliott H. Berger, Rick Neitzel, and Cynthia A. Kladden, Noise Navigator Sound Level Database with Over 1700 Measurement Values, July 6,
2010.
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Table 4.13-6: Mechanical Equipment Noise Levels
Receptor
Distance
to
Receptor
(feet)1
Modeled
Noise Level
at
Receptor
(dBA)
Daytime
Noise
Standard
(dBA) 2
Standard
Exceeded
?
Nighttime
Noise
Standard
(dBA) 2
Standard
Exceeded
?
3. The mechanical equipment would be shielded and the existing approximately 6-foot block wall along the western property line would
remain. The noise level accounts for a 10 dBA reduction
4. The Whittier Narrows Golf Course would not be operational during nighttime hours. Therefore, the nighttime threshold is not
applicable.
As shown in Table 4.13-6, the noise levels from mechanical equipment would exceed the City’s
nighttime threshold of 45 dBA Leq at the residential uses located to the west of the Project Site
(Sensitive Receptor 3). MM NOI-3 requires that mechanical equipment (e.g., air conditioning
units) be located a minimum of 38 feet from residential receptors. With implementation of MM
NOI-3, mechanical noise would be reduced to 44.4 dBA Leq at Sensitive Receptor 3. Therefore,
mechanical noise would not exceed City daytime or nighttime exterior standards and impacts
would be less than significant with mitigation incorporated.
Trash and Recycling Pick Up
Trash and recycling would be collected along Walnut Grove Avenue. Trash and recycling trucks
and pickup activities customarily generate noise levels of approximately 85 dBA at 3.3 feet.67
Trash and recycling truck pickup activity would occur infrequently and intermittently at the
Project Site. Furthermore, trash and recycling pickup currently occurs under existing conditions
and would not be a new noise source. The hours of trash and recycling pickup activity would
depend on the service provider and would not be regulated by the Project. Therefore, Project
implementation would not result in any significant effects relating to trash/recycling truck pickup
noise levels.
Parking
The townhouse buildings would include private attached garages. The Project Site would include
guest parking along internal roadways for residential guests. Noises associated with parking
activities include vehicles starting and stopping, vehicle doors closing, car horns and car alarms,
loading and unloading, car radios, and conversations. The noise levels from these activities
typically range from 53 to 61 dBA at 50 feet and are short-term.68 Parking activity would occur
intermittently throughout the day and currently occurs under existing conditions. As such,
parking activity noise associated with Project implementation would not be a new noise source
and impacts would be less than significant.
Dog Park
The Project would include a small and large dog park on the northeast corner of the Project Site.
The dog park would be fenced and would include bench seating, picnic tables, and trash
67 Kariel, H. G., Noise in Rural Recreational Environments, Canadian Acoustics 19(5), 3-10, 1991.
68 Ibid.
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receptables. Noises associated with dog parks include dogs barking and howling, people talking,
and music playing. For purposes of analysis, the reference noise level from dogs barking and
howling would be 73 dBA at approximately 3 feet.69 Table 4.13-7: Dog Park Noise Levels
summarizes the dog park noise levels at the nearest sensitive receptors.
Table 4.13-7: Dog Park Noise Levels
Receptor
Distance
to
Receptor
(feet)1
Modeled
Noise
Level at
Receptor
(dBA)
Daytime
Noise
Standard
(dBA)2
Standard
Exceeded
?
Nighttime
Noise
Standard
(dBA)2
Standard
Exceeded
?
1 – University
of the West
(south)
693 25.7 65 No 60 No
2 – Residential
Uses (south) 1,217 20.8 60 No 45 No
3 – Residential
Uses (west) 504 28.5 60 No 45 No
4- Whittier
Narrows Golf
Course (east)
97 42.8 60 No N/A3 No
5 – Residential
Uses
(southeast)
1,020 22.4 60 No 45 No
1. Distance from the dog park to the nearest sensitive receptor.
2. Pursuant to City Noise Ordinance the residential daytime threshold is 60 dBA, the residential nighttime threshold is 45
dBA, the commercial daytime noise threshold is 65 dBA, and the nighttime commercial threshold is 60 dBA.
3. The Whittier Narrows Golf Course would not be operational during nighttime hours. Therefore, the nighttime
threshold is not applicable.
Outdoor Space
The Project would include a community pool, group spa, cabanas, gas barbeque grills, community
garden, picnic tables, open lawn play area, and tot-lot with play equipment. Per Assembly Bill
1307, PRC Section 21085, for residential uses, the effects of noise generated by Project occupants
and their guests on human beings are not a significant effect on the environment. Therefore, no
further analysis is required.
Pool Equipment and Water Pump Station
The Project would include a community pool, group spa, and water pump station located on the
southeast corner of the Project Site. The pool and spa equipment and water pump station would
69 Elliott H. Berger, Rick Neitzel, and Cynthia A. Kladden, Noise Navigator Sound Level Database with Over 1700 Measurement Values, July 6,
2010.
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be entirely enclosed within a building and would not result in any measurable noise levels within
the Project vicinity. Impacts would be less than significant, and no mitigation is required.
Composite Noise Levels
An evaluation of the combined noise levels from the Project’s various on-site operational noise
sources (i.e., composite noise level) was conducted to ascertain the potential maximum Project-
related noise level. It is conservatively assumed that operational noise sources at the Project site
would occur in a constant, simultaneous manner. However, noise sources would occur
intermittently throughout the day. This analysis considers an exceedance of the noise standard
at a sensitive receptor and a 5 dBA increase in noise levels over the existing ambient noise
environment as the daytime significance criterion. Since ambient noise levels were not measured
during the nighttime period, an exceedance of the noise standard is considered as the nighttime
significance criterion.
Table 4.13-8: Composite Noise Levels presents the composite noise level from the on-site
Project-related noise sources with incorporation of MM NOI-3. As shown in Table 4.13-8, Project-
generated composite noise levels would not cause a 5-dBA ambient increase at the nearest
sensitive receptors. Impacts associated with Project operational composite noise would be less
than significant.
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Table 4.13-8: Composite Noise Levels
Sensitive
Receptor
Mechanical
Equipment
(dBA Leq)
Dog Park
(dBA Leq)
Project
Composite
(dBA Leq)
Ambient
(dBA Leq)1
Ambient +
Project
(dBA Leq)
Incremental
Increase
(dBA Leq)
Increase
Threshold2 Significant?3
1 – University of
the West 46.2 25.7 46.3 53.7 54.4 0.7 5.0 No
2 – Residential
Uses 29.1 20.8 29.7 67.4 67.4 0.0 5.0 No
3 – Residential
Uses 44.44 28.5 44.5 44.5 47.5 3.0 5.0 No
4- Whitter
Narrows Golf
Course
45.8 42.8 47.6 68.8 68.8 0.0 5.0 No
5 – Residential
Uses 30.7 22.4 31.4 67.4 67.4 0.0 5.0 No
1. Refer to Table 4.13-2: Existing Noise Measurements for the representative ambient noise levels.
2. A 5-dBA incremental increase is considered to be perceivable.
3. Potential impacts would occur if the noise generated by the Project would exceed the daytime noise standard and cause an incremental noise increase of 5 dBA above existing
ambient conditions or exceed the nighttime noise standard.
4. Mechanical equipment noise levels at Sensitive Receptor 3 incorporates MM NOI-3, which requires a minimum distance of 38 feet between mechanical equipment and off-site
sensitive receptors.
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Mobile Traffic Noise
Project implementation would result in an increase in traffic trips along roadways near the
project site. In general, a 3‐dBA increase in traffic noise is barely perceptible to people, while a
5‐dBA increase is readily noticeable. Traffic volumes on Project area roadways would have to
approximately double for the resulting traffic noise levels to generate a barely perceptible 3‐dBA
increase.70 According to Replica HQ, Walnut Grove Avenue between Rush Street and Drayer Lane
has an existing ADT of 9,055.71 As such, the 1,375 total daily vehicle trips72 attributable to the
Project would not double the existing traffic volumes on Walnut Grove. The proposed Project
would not generate enough traffic to result in a noticeable 3-dBA increase in ambient noise levels
and impacts associated with Project-generated mobile traffic would be less than significant.
Mitigation Measure
MM NOI-1 Noise Shielding and Muffling. Power construction equipment (including
combustion engines), fixed or mobile, shall be equipped with noise shielding and
muffling devices consistent with manufacturers’ standards or the Best Available
Control Technology. All equipment shall be properly maintained, and the
Applicant or Owner shall require any construction contractor to keep
documentation on-site during any earthwork or construction activities
demonstrating that the equipment has been maintained in accordance with
manufacturer’s specifications.
MM NOI-2 Temporary Walls. Noise barriers, such as temporary walls (minimum ½-inch thick
plywood) or sound blankets (minimum STC 25 rating), that are a minimum of eight
feet tall, shall be erected along the western property line between construction
activities and Noise-Sensitive Uses located adjacent to the west of the Project Site.
MM NOI-3 Mechanical Equipment Buffer. Prior to the issuance of building permits, the
Applicant shall submit site plans showing the location of stationary mechanical
equipment. Stationary mechanical equipment such as air conditioning units shall
be located at a minimum distance of 38 feet from off-site sensitive receptors. In
the event that stationary mechanical equipment cannot be set back by a minimum
of 38 feet, the Applicant shall submit a noise memorandum showing that
equipment would be equipped with sufficient sound attenuation (e.g., shielding)
to reduce noise at adjacent residential receptors to a maximum of 44.4 dBA.
70 According to the California Department of Transportation, Technical Noise Supplement to Traffic Noise Analysis Protocol, 2013, it takes a
doubling of traffic to create a noticeable (i.e., 3-dBA) noise increase.
71 ReplicaHQ, Replica Annual Average Daily Traffic (AADT) Data, 2024, https://www.replicahq.com/aadt. Accessed September 16, 2025.
72 Kimley-Horn and Associates, Inc., Traffic Study for the Proposed 1515 Walnut Grove Avenue Project in the City of Rosemead, 2025.
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4.13b Would the project generate excessive groundborne vibration or groundborne noise
levels?
Less Than Significant Impact With Mitigation Incorporated.
On-Site Construction Vibration
Increases in groundborne vibration levels attributable to the Project would be primarily
associated with short-term construction-related activities. Project construction would have the
potential to result in varying degrees of temporary groundborne vibration, depending on the
specific construction equipment used and the operations involved. Ground vibration generated
by construction equipment spreads through the ground and diminishes in magnitude with
increases in distance. The results from vibration can range from no perceptible effects at the
lowest vibration levels, to low rumbling sounds and perceptible vibration at moderate levels, to
slight damage at the highest levels. Groundborne vibrations from construction activities rarely
reach levels that damage structures.
The types of potential construction vibration impacts include human annoyance and building
damage. Human annoyance occurs when construction vibration rises significantly above the
threshold of human perception for extended periods of time at sensitive receptors. Land uses
where people sleep or read are particularly sensitive to groundborne vibration. Building damage
can be cosmetic or structural. Ordinary buildings that are not particularly fragile would not
experience any cosmetic damage (e.g., plaster cracks) at distances beyond 30 feet. This distance
can vary substantially depending on the soil composition and underground geological layer
between vibration source and receiver. In addition, not all buildings respond similarly to vibration
generated by construction equipment.
The ground-borne vibration generated by construction equipment spreads through the ground
and diminishes in magnitude with increases in distance. Equipment expected to be used at the
Project Site that FTA guidance includes reference vibration levels for include vibratory roller,
large bulldozer, loaded haul trucks, and small bulldozer.
The City has not established quantitative vibration standards. Therefore, this analyses uses the
FTA criteria of 0.3 in/sec PPV to evaluate building damage and the Caltrans’s criteria of 0.02 in/sec
to evaluate human annoyance at the nearest structure to the Project Site. Table 4.13-9: Typical
Construction Equipment Vibration Levels lists the vibration levels for typical construction
equipment at 25 feet (reference distance) and 5 feet (the distance from the nearest structure to
the Project Site property line).
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Table 4.13-9: Typical Construction Equipment Vibration Levels
Equipment
Reference Level
PPV at 25 Feet
(in/sec)
PPV at 5 feet
(in/sec)1, 2
Vibratory Roller 0.21 2.348
Large Bulldozer 0.089 0.995
Loaded Trucks 0.076 0.850
Small Bulldozer 0.003 0.034
Exceeds Building Damage Threshold3 0.3 Yes
Exceeds Human Annoyance Threshold4 0.2 Yes
1. Calculated using the following formula: PPVequip = PPVref x (25/D)1.5, where: PPVequip = the peak particle velocity in in/sec
of the equipment adjusted for the distance; PPVref = the reference vibration level in in/sec from Table 7-4 of the Federal
Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018; D = the distance from the
equipment to the receiver.
2. The distance from the nearest structure to the Project Site property line. The nearest structures to the Project Site are
residential uses located approximately 5 feet to the west.
3. Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
4. California Department of Transportation, Transportation and Construction Vibration Guidance Manual, 2020.
Source: Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
As stated above, construction activities are anticipated to occur up to the Project boundary line.
The nearest structures to the Project Site property line are residential uses (Sensitive Receptor
3) located approximately 5 feet to the west. As indicated in Table 4.13-10: Mitigated
Construction Equipment Vibration Levels, vibration velocities from typical heavy construction
equipment operations that would be used during Project construction would exceed the FTA
building damage threshold of 0.3 in/sec PPV and the Caltrans’ human annoyance threshold of 0.2
in/sec PPV at 5 feet. MM NOI-4 would be required to reduce vibration impacts to a less than
significant level. MM NOI-4 would require buffer distances from the vibratory construction
equipment to the adjacent receptors (residential uses to the west). Use of vibratory rollers would
be prohibited within 26 feet, large bulldozers (dozers 50 tons and larger) would be prohibited
within 15 feet, and loaded trucks would be prohibited within 14 feet of the residential uses to
the west (Sensitive Receptor 3). As shown in Table 4.13-10, impacts with regard to structural
damage and human annoyance at the nearest structure would be less than significant with
implementation of MM NOI-4.
Table 4.13-10: Mitigated Construction Equipment Vibration Levels
Equipment
Reference
Level
PPV at 25
Feet (in/sec)
Required
Distance
(feet)
PPV at
Mitigated
Distance
(in/sec
PPV)1
Significance
Threshold
(in/sec PPV)
Exceed
Significance
Thresholds?
Building Damage2
Vibratory
Roller 0.210 20 0.294 0.3 No
Large Bulldozer 0.089 12 0.268 0.3 No
Loaded Trucks 0.076 11 0.260 0.3 No
Human Annoyance3
Vibratory 0.210 26 0.198 0.2 No
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Table 4.13-10: Mitigated Construction Equipment Vibration Levels
Equipment
Reference
Level
PPV at 25
Feet (in/sec)
Required
Distance
(feet)
PPV at
Mitigated
Distance
(in/sec
PPV)1
Significance
Threshold
(in/sec PPV)
Exceed
Significance
Thresholds?
Roller
Large Bulldozer 0.089 15 0.192 0.2 No
Loaded Trucks 0.076 14 0.181 0.2 No
1. Calculated using the following formula: PPVequip = PPVref x (25/D)1.5, where: PPVequip = the peak particle velocity in in/sec of
the equipment adjusted for the distance; PPVref = the reference vibration level in in/sec from Table 7-4 of the Federal Transit
Administration, Transit Noise and Vibration Impact Assessment Manual, 2018; D = the distance from the equipment to the
receiver.
2. Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
3. California Department of Transportation, Transportation and Construction Vibration Guidance Manual, 2020.
Source: Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
Off-Site Construction Vibration
Project construction would additionally include off-site sidewalk and grind and overlay roadway
improvements along the Walnut Grove Avenue frontage. The off-site improvements would
require the use of vibratory rollers, loaded trucks, pavers, paving equipment, loaders, and
tractors. The FTA guidance includes reference vibration levels for a vibratory roller and loaded
trucks.
The nearest structure to the off-site improvements would be located as near as 280 feet to the
west (i.e., University of the West). As the structure would be located further from the off-site
improvements than the required buffer distances listed in Table 4.13-10, it can be assumed that
the vibration from off-site improvements would not exceed the FTA building damage threshold
of 0.3 in/sec PPV or Caltrans’ human annoyance threshold of 0.2 in/sec PPV. As such, impacts
associated with off-site improvement vibration would be less than significant, and no mitigation
is required.
With respect to construction trucks, Project construction would involve truck travel along nearby
roadways, generating vibration events with each passing truck. During excavation, soil would be
stockpiled by trucks within designated areas of the project site prior to export. According to the
FTA’s Transit Noise and Vibration Impact Assessment, a truck rarely creates vibration levels that
exceed 70 VdB (equivalent to 0.012 in/sec PPV) when on a roadway. The factors influencing levels
of ground-borne vibration include vehicle speed, vehicle suspension, and wheel condition and
type. The frequency of vibration events is not listed as an influencing factor for vibration velocity
by the FTA. As such, multiple trucks traveling along the roadway would increase the frequency of
vibration events but would not affect the vibration velocity experienced by receptors. Impacts
would be less than significant, and no mitigation is required.
Operational Vibration
With respect to vibration-generating activities, operation of the Project would primarily involve
personal automobiles used by residents accessing the parking spaces, occasional delivery trucks
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(such as UPS, FedEx, etc.), and trash and recycling collection trucks. Due to the rapid drop-off rate
of ground-borne vibration and the short duration of the associated events, vehicular traffic-
induced ground-borne vibration is rarely perceptible beyond the roadway right-of-way, and
rarely results in vibration levels that cause damage to buildings in the vicinity.73 According to the
FTA’s Transit Noise and Vibration Impact Assessment, trucks such as delivery trucks, refuse
collection trucks, and occasional moving trucks rarely create vibration levels that exceed 70 VdB
(equivalent to 0.012 in/sec PPV) when they are on roadways.74 Therefore, approval of the Project
would not result in any significant effects relating to ground-borne vibration during Project
operation.
Mitigation Measure
MM NOI-4 On-Site Construction Vibration Control. The following measure shall be
incorporated on all grading and building plans and specifications subject to
approval of the City’s Building and Safety Division prior to issuance of a grading
permit:
• The developer shall ensure vibratory construction equipment will not operate
within the construction buffer zone adjacent to the residential buildings along
the western Project Site boundary. Specifically, loaded trucks shall not operate
within 14 feet of the residential buildings to the west of the Project Site, large
bulldozers (50 tons/100,000 pounds or larger) shall not operate within 15 feet
of the residential buildings to the west of the Project Site, and vibratory rollers
shall not operate within 26 feet of the residential buildings to the west of the
Project Site.
• The developer shall require the use of non-vibratory rollers (i.e., static or
pneumatic rollers) or other less vibratory equipment within the buffer zone
adjacent to the residential buildings along the western Project Site boundary.
4.13c Would the project be located within the vicinity of a private airstrip or an airport land
use plan or, where such a plan has not been adopted, within two miles of a public airport
or public use airport, would the Project expose people residing or working in the project
area to excessive noise levels?
No Impact. Refer to Response 4.9e. The Project Site is located approximately 3.3-miles to the
southwest of the San Gabriel Valley Airport and is not located within the airport’s influence area
or noise contours. The Project Site is located approximately 0.14 miles to the southwest of the
SCE Rosemead Heliport. The heliport is privately owned and operated by SCE to occasionally
monitor and inspect electrical infrastructure. As such, commercial activity would not occur at
the heliport. The helicopter activity would be short in duration and permission would be required
prior to any helicopter landing or launching from the helipad. The heliport noise is part of the
existing noise environment and use of the heliport would not result in exposure of workers or
73 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
74 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018.
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residents at the Project Site to excessive noise levels. As the Project Site is not located within the
vicinity of a private airstrip or airport land use plan, nor is it located within two miles of a private
or public use airport, the Project would not expose people residing or working at the Project Site
to excessive airport or airstrip-related noise levels, and no impact would occur.
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4.14 Population and Housing
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Induce substantial unplanned population growth in
an area, either directly (for example, by proposing
new homes and businesses) or indirectly (for
example, through extension of roads or other
infrastructure)?
X
b) Displace substantial numbers of existing people or
housing, necessitating the construction of
replacement housing elsewhere?
X
Impact Analysis
4.14a Would the project induce substantial unplanned population growth in an area, either
directly (for example, by proposing new homes and businesses) or indirectly (for
example, through extension of roads or other infrastructure)?
Less Than Significant Impact. The Project proposes to demolish the vacant office building and
detached central plant building and construct 191 residential dwelling units. Project construction
would temporarily increase the number of persons present at the Project Site. However, these
construction workers would only be present at the Project Site during Project construction. Based
on the City’s average household size of 3.8, the 191 dwelling units would result in a population
increase of approximately 726 persons.75
Potential population growth impacts are also assessed based on a project’s consistency with
adopted plans that have addressed growth management from a local and regional standpoint.
As stated on page 37 of SCAG’s Connect SoCal 2024 Demographics and Growth Forecast Technical
Report, a rough estimate of the future jurisdiction-level population based on Connect SoCal’s
household forecast can be derived using a county-level population to housing ratio from Table
12 of the [Demographics and Growth Forecast] and applying it to a jurisdiction’s future household
growth. Table 12 of the Forecast shows that Los Angeles County has a projected population of
10,793,000 population and 4,155,000 households in 2050, resulting in a population to household
ratio in 2050 of 2.60:1. As stated in Table 13 of the Forecast, the City is projected to have 16,100
households in 2050. Based on 16,100 households, the 2050 population for the City is projected
to be 41,821 population, which represents a decrease in households compared to 2019. Based
on SCAG’s 2019 Local Profiles Report average household size of 3.8, the City’s projected 16,100
75 SCAG, Rosemead Local Profiles Report 2019, https://cdnsm5-
hosted.civiclive.com/UserFiles/Servers/Server_10034989/File/Gov/City%20Departments/Community%20Development/Plan
ning/Housing%20Element/Adopted%20Rosemead%202021-2029%20Housing%20Element_CERTIFIED%20080122.pdf.
Accessed August 12, 2025.
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households in 2050 would result in 61,180 population. This represents an increase of 9,780
population between 2019 and 2050.
The Project’s anticipated population growth (726 persons) would represent approximately 1.2
percent of the City’s anticipated 2050 population, and approximately 7.4 percent of the City’s
anticipated growth between 2019 and 2050. Thus, the Project’s estimated population growth
would be within regional growth projections of the City. Additionally, the Project does not
propose the extension of new major infrastructure or uses that would indirectly induce
substantial population growth. Therefore, impacts would be less than significant.
4.14b Would the project displace substantial numbers of existing people or housing,
necessitating the construction of replacement housing elsewhere?
No Impact. There is no housing on the Project Site. Therefore, the Project would not displace
existing people or housing, or require construction of replacement housing elsewhere. No impact
would occur in this regard.
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4.15 Public Services
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project result in substantial adverse physical impacts associated with the provision of new or
physically altered governmental facilities, need for new or physical altered governmental facilities, the
construction of which could cause significant environmental impacts, in order to maintain acceptable service
ratios, response times or other performance objectives for any of the public services:
a) Fire protection? X
b) Police protection? X
c) Schools? X
d) Parks? X
e) Other public facilities? X
Impact Analysis
4.15a Would the project result in substantial adverse physical impacts associated with the
provision of new or physically altered governmental facilities, need for new or physical
altered governmental facilities, the construction of which could cause significant
environmental impacts, in order to maintain acceptable service ratios, response times
or other performance objectives for fire protection?
Less Than Significant Impact. Fire protection services within the City are provided by the LACFD.
The nearest LACFD Fire Stations are LACFD Station 4, located 0.9 miles from the Project Site at
2644 North San Gabriel Boulevard within the City, and LACFD Station 90, located 1.9 miles from
the Project Site at 10115 East Rush Street within the City of South El Monte.
Construction would last approximately 34 months and would require temporary lane closures on
streets adjacent to the Project Site for utility relocation and delivery of materials. However,
Project construction would not require the complete closure of any public streets during
construction, and temporary construction activities would not impede the use of the streets for
emergencies or access for emergency vehicles.
Additionally, the Project would be designed according to California Fire Code (CCR Title 24, Part
9) included in RMC Chapter 8.24, Fire Prevention Code, which regulates fire-resistant
construction, emergency planning, fire protection system, and emergency access throughout the
City. The Project plans would further be reviewed by the City’s Building and Safety Division to
ensure that the fire protection requirements are met as part of the permitting process. The
Project would provide adequate circulation and access to facilitate emergency response during
Project operation in accordance with City standards. The Project would provide two new
driveways along Walnut Grove Avenue and fire lane access throughout the Project Site. The new
driveways would comply with City requirements and applicable fire code standards for layout
and turning movements. The Project’s estimated 726 persons would be less than the 904
employees that previously worked in the existing SCE office building, which was adequately
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served by LACFD. Nevertheless, the Project would comply with the LACFD standards and
conditions as part of their review of the Project. Additionally, the Project would comply with City
Ordinance 949 to pay the appropriate Development Impact Fees (DIFs) related to public safety
and based on the Multi-Family Residential fee per dwelling unit. With compliance with LACFD
and payment of the DIFs, the provision of a new or physically altered fire station would not be
required. Therefore, impacts related to fire protection services would be less than significant.
4.15b Would the project result in substantial adverse physical impacts associated with the
provision of new or physically altered governmental facilities, need for new or physical
altered governmental facilities, the construction of which could cause significant
environmental impacts, in order to maintain acceptable service ratios, response times
or other performance objectives for police protection?
Less Than Significant Impact. Police protection services are provided by the City’s Public Safety
Department and the Los Angeles County Sheriff Department (LASD). The City’s Public Safety
Center, located at 8301 Garvey Avenue approximately 1.1 mile north of the Project Site, provides
safety and security-related services for the City. The City’s Chief of Police (LACSD Lieutenant)
manages the City’s public safety services, including law enforcement services with the LACSD and
County Probation Department and fire services with the Los Angeles County Fire Department.
LACSD deputies assigned to the City work directly out of the Public Safety Center. As discussed in
Response 4.15a, Project construction could encroach on adjacent roadways and temporarily
impact street access and traffic flow. However, Project construction would not require the
complete closure of any public streets during construction, and temporary construction activities
would not impede the use of the streets for emergencies or access for emergency vehicles.
During any temporary partial street closure, emergency access and traffic detours would be
established in coordination with the City.
During operations, the Project would include new security gates enclosing the Project Site along
Walnut Grove Avenue along with double gated entry around the proposed dog park, a block wall
along the southern and northern perimeters of the Project Site, and the existing block wall along
the western perimeter of the Project Site. The Project would include two secure access gates
(each with one entry and one exit gate) for each proposed driveway. The access gates would
remain locked, except during operations and maintenance activities. A pedestrian gate would
also be located adjacent to each gate that would provide access to the sidewalk along Walnut
Grove Avenue.
The Project’s estimated 726 persons would be less than the 904 employees that previously
worked in the existing SCE office building, which was adequately served by LASD. Nevertheless,
the Project would comply with City Ordinance 949 to pay the appropriate DIFs related to public
safety and based on the Multi-Family Residential fee per dwelling unit would construct 191 new
dwelling units. Based on the Project’s design and implementation of the security measures, as
well as payment of the DIFs, the provision of a new or physically altered sheriff station would not
be required. Therefore, impacts related to police protection services would be less than
significant.
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4.15c Would the project result in substantial adverse physical impacts associated with the
provision of new or physically altered governmental facilities, need for new or physical
altered governmental facilities, the construction of which could cause significant
environmental impacts, in order to maintain acceptable service ratios, response times
or other performance objectives for schools?
Less Than Significant Impact. The Project Site is located in Montebello Unified School District.
Schools that serve the Project Site include Portrero Heights Elementary School, Macy
Intermediate School, and Schurr High School. Given the declining population in the City over the
past 10 years, including the reduction in enrollment with Montebello Unified School District,
there would be adequate capacity in the nearby schools to accommodate the Project’s school
age residents.76,77 Nevertheless, development of the Project would be subject to California
Government Code Section 65995, which would allow the Montebello Unified School District to
collect impact fees from developers of new residential and commercial space. Conformance to
California Government Code Section 65995 is deemed to provide full and complete mitigation of
impacts to school facilities. Therefore, with payment of the impact fees, the Project would not
result in substantial adverse physical impacts associated with the provision of new or physically
altered schools, and impacts would be less than significant.
4.15d Would the project result in substantial adverse physical impacts associated with the
provision of new or physically altered governmental facilities, need for new or physical
altered governmental facilities, the construction of which could cause significant
environmental impacts, in order to maintain acceptable service ratios, response times
or other performance objectives for parks?
Less Than Significant Impact. The nearest park and recreational area to the Project Site is
Whittier Narrows Recreation Area, which includes over 1,500 acres of parkland.78 The closest
park and recreational areas within the City are Triangle Park, located at the southeast intersection
of Walut Grove Avenue and San Gabriel Boulevard approximately 2,000 feet south of the Project
Site, and Klingerman Park, located at 880 Klingerman Avenue approximately 2,700 feet northeast
of the Project Site. The Project would develop 191 residential dwelling units and 126,015 total
square feet of open space including landscapes, community garden, central garden court, a
playground, pool/spa, dog park, and areas available for common and/or active recreation areas.
Though the Project could cause a potential increase in demand for park facilities as a result of
the Project’s increase in population, the provision of on-site open space and recreational facilities
would reduce the need for off-site surrounding recreational areas.
Furthermore, the Applicant would be required to pay DIFs, which include park fees. The DIFs
could be used by the City to provide park facilities as allowed by RMC Chapter 17.170.090,
76 California Demographics, Rosemead Demographic Statistics, Population, https://www.california-
demographics.com/rosemead-demographics. Accessed December 5, 2025.
77 Montebello Unified School District had a 2019 enrollment of 24,324 and a 2024 enrollment of 19,195, resulting in a 21.1
percent reduction. Source: SFEDup, Public School Enrollment Trends, https://sfeducation.substack.com/p/public-school-
enrollment-trends. Accessed December 5, 2025.
78 Los Angeles County Department of Parks & Recreation, Whittier Narrows Recreation Area,
https://parks.lacounty.gov/whittier-narrows-recreation-area/. Accessed August 12, 2025
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Distribution of impact fee funds, which includes the purchase of land, design, construction,
equipment, etc. as deemed necessary to serve City residents, which would include the Project’s
residents. With payment of the required DIFs, the Project would not result in substantial adverse
physical impacts associated with the provision of new or physically altered parks, and impacts
would be less than significant.
4.15e Would the project result in substantial adverse physical impacts associated with the
provision of new or physically altered governmental facilities, need for new or physical
altered governmental facilities, the construction of which could cause significant
environmental impacts, in order to maintain acceptable service ratios, response times
or other performance objectives for other public facilities?
Less Than Significant Impact. The nearest library to the Project Site is the Rosemead Library,
located at 8800 Valley Boulevard approximately 2.5 miles north of the Project Site. The Project
would develop the Project Site with 191 residential dwelling units, which could result in increased
demand for library services and resources on the Los Angeles County Library System. While the
increase in population as a result of the Project may create a demand for other public facilities,
the Project would not create substantial capacity or service level problems that would require
the provision of new or physically altered libraries in order to maintain an acceptable level of
other government services. Therefore, impacts would be less than significant.
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4.16 Recreation
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Increase the use of existing neighborhood and
regional parks or other recreational facilities such
that substantial physical deterioration of the facility
would occur or be accelerated?
X
b) Does the project include recreational facilities or
require the construction or expansion of recreational
facilities which might have an adverse physical effect
on the environment?
X
Impact Analysis
4.16a Would the project increase the use of existing neighborhood and regional parks or other
recreational facilities such that substantial physical deterioration of the facility would
occur or be accelerated?
4.16b Does the project include recreational facilities or require the construction or expansion
of recreational facilities which might have an adverse physical effect on the
environment?
Less Than Significant Impact. See Response 4.15.d above. The Whittier Narrows Recreation Area,
which is located just outside of City limits in unincorporated Los Angeles County, includes over
1,500 acres of parkland and is located east of the Project Site. Additionally, the Whittier Narrows
Golf Course is adjacent to the Project Site, separated from the Project Site by Walnut Grove
Avenue. Four additional smaller parks are located near the Project Site: Triangle Park
(approximately 2,000 feet south), Klingerman Park (approximately 2,700 feet northeast), Potrero
Heights Park (approximately 3,200 feet east), and Jay Imperial Park (approximately 4,000 feet
northwest).
The Project would develop 191 residential dwelling units and 126,015 total square feet of open
space including landscapes, community garden, central garden court, a playground, pool/spa,
dog park, and areas available for common and/or active recreation areas. Though the Project
would cause an increase in population, the provision of on-site open space and recreational
facilities would reduce the need for off-site surrounding recreational areas.
Furthermore, the Applicant would be required to pay DIFs to reduce potential parks and
recreation impacts. Therefore, with the provision of the on-site open space and recreational
facilities and payment of the DIFs, the Project would not increase the use of existing
neighborhood and regional parks and facilities such that substantial physical deterioration would
occur or be accelerated. As discussed throughout this IS/MND, the construction of the Project’s
open space and recreational areas would not result in an adverse physical effect on the
environment. Impacts would be less than significant.
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4.17 Transportation
This Section is based on the Traffic Study for the 1515 Walnut Grove Avenue Project and the
Vehicle Miles Traveled Assessment, both prepared by Kimley-Horn and are included in Appendix
L: Traffic Study and Appendix M: Vehicle Miles Traveled Analysis.
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Conflict with a program plan, ordinance, or policy
addressing the circulation system, including transit,
roadway, bicycles, and pedestrian facilities?
X
b) Conflict or be inconsistent with CEQA Guidelines
Section 15064.3, subdivision (b)? X
c) Substantially increase hazards due to a geometric
design feature (e.g., sharp curves or dangerous
intersections) or incompatible uses (for example,
farm equipment)?
X
d) Result in inadequate emergency access? X
Impact Analysis
4.17a Would the project conflict with a program plan, ordinance, or policy addressing the
circulation system, including transit, roadway, bicycle, and pedestrian facilities?
No Impact. Regional vehicle access to the Project Site is provided by the SR 60 and SR 164
(Rosemead Boulevard), located approximately 0.54 miles south and 1.04 miles east, respectively.
Local vehicle access to the Project Site is provided via Rush Street, located approximately 0.20
miles north of the Project Site and Walnut Grove Avenue directly east of the Project Site.
There are existing pedestrian sidewalks along Walnut Grove Avenue to the east of the Project
Site. The other boundaries of the Project Site abut a public street, residential properties, a
corporate center, and a university, and consist of landscape buffers or trees with no vehicular or
pedestrian access proposed. The Project would not impair existing pedestrian sidewalks or transit
services along Walnut Grove Avenue. The Project would include public right of way
improvements such as a parkway and improved sidewalk along Walnut Grove Avenue. The infill
development would encourage the use of existing pedestrian and transit services in the Project
area. The Project would not conflict with any adopted policies, plans, or programs regarding
alternative transportation because no changes to existing transportation policies, plans, or
programs would result from Project implementation. Therefore, the Project would result in no
impact in this regard.
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4.17b Would the project conflict or be inconsistent with CEQA Guidelines Section 15064.3,
subdivision (b)?
Less Than Significant Impact. CEQA Guidelines Section 15064.3 codifies the change from level of
service to VMT as a metric for transportation impact analysis. Pursuant to SB 743, VMT analysis
is the primary method for determining CEQA impacts related to transportation. According to
CEQA Guidelines Section 15064.3(a), VMT refers to the amount and distance of automobile travel
attributable to a project. The City’s Transportation Study Guidelines for Vehicle Miles Traveled
and Level of Service Assessment (Transportation Study Guidelines), adopted in November 2024,
provides details on appropriate screening thresholds to provide transportation analysis
requirements for land development, roadway projects, and specific plans in the City. As stated
within the Transportation Study Guidelines, there are three types of screening that may be
applied to effectively screen projects from project-level assessment. A project may be screened
out of VMT analysis if it meets one or more of the following screening steps: (1) Transit Priority
Area (TPA) Screening; (2) Low VMT Area Screening; or (3) Project Type Screening. The Project
would not meet any of the screening steps; therefore, a quantitative VMT analysis was conducted
(see Appendix M).
The VMT analysis was completed using the latest version of the SCAG Travel Demand Model
(SCAG Model), the methodology the City recommends to measure VMT. Based on the City’s
guidelines, a project would result in a significant project-generated VMT impact if either of the
following conditions are satisfied:
• The baseline project-generated VMT per capita exceeds 15 percent below the San Gabriel
Valley Council of Governments (SGVCOG) baseline VMT per capita.
• The cumulative project-generated VMT per capita exceeds 15 percent below the SGVCOG
baseline VMT per capita.
The VMT impact is determined by normalizing the boundary VMT by the service population and
comparing the results between the with and the without Project conditions. The Project effect
on VMT, using the boundary method, was evaluated within a 35-mile buffer area from the
Project’s transportation analysis zone (TAZ). As shown in Table 2 of the VMT Analysis, the Project-
generated VMT per capita (16.23) is above the SGVCOG threshold (13.37), resulting in a VMT
reduction requirement of 17.6 percent to achieve a less than significant VMT impact. Table 3 of
the VMT analysis shows that the Cumulative Year (2050) Project-generated VMT per capita
(15.92) is also above the SGVCOG threshold (13.37). As shown in Table 4 and Table 5 of the VMT
Analysis, there is an increase in Project Boundary VMT between Opening Year No Project and
Plus Project conditions. However, the Boundary VMT per service population remains the same
between the No Project (14.16) and the Plus Project (14.16) conditions. Similarly, Table 5 shows
this same relationship under the Cumulative year conditions. The cumulative Plus Project
Boundary VMT per service population (12.90) remains the same as No Project (12.90).
Key Transportation Demand Management (TDM) measures appropriate to the region were
identified by SGVCOG and are provided in the SGVCOG VMT Assessment Tool. Additionally, the
California Air Pollution Control Officers Association (CAPCOA) Handbook for Analyzing
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Greenhouse Gas Emission Reductions, Assessing Climate, October 2024 is one of the primary
bases for estimating mitigation effects of several TDM measures in California. Because the Project
would increase the number of dwelling units per acre compared to the surrounding area, which
supports shorter trip lengths and encourages alternative modes of transportation, the Project’s
VMT would be reduced by up to 27.8 percent, thereby reducing the Project’s VMT by more than
the 17.6 percent needed to be below the SGVOG threshold. Therefore, impacts would be less
than significant.
4.17c Would the project substantially increase hazards due to a geometric design feature
(e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm
equipment)?
Less Than Significant Impact. Vehicular access is currently provided via two driveways off Walnut
Grove Avenue. The Project would provide two new driveways along Walnut Grove Avenue, one
to the north and one to the south. Both the northern and southern entryways would provide a
two-way gated vehicle ingress and egress to the Project Site and internal roadway system. On
either side of the vehicle gates would be separate pedestrian gates and pathways to the Project
Site. The Project entryways would feature distinctive Project monument signs, visitor dial up
kiosks, and enhanced vehicular pavement treatments. Internal walkways and enhanced
crosswalks would provide pedestrian access to various amenities within the Project Site.
The designs and dimensions of the driveways would be designed to comply with the City’s current
design requirements. The Project would not have the potential to increase hazards due to
geometric design. Thus, the Project does not propose any improvements with potential to
increase hazards due to incompatible uses. The Project would result in a less than significant
impact in this regard.
4.17d Would the project result in inadequate emergency access?
Less Than Significant Impact. See Response 4.9f. The Project would be designed according to
applicable fire code standards and would provide adequate circulation and access to facilitate
emergency response. LACFD has reviewed and approved the Project’s site plan on emergency
access on July 10, 2025.
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4.18 Tribal Cultural Resources
This Section is based on AB 52 communications initiated by the City.
Environmental Issue
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 tribal cultural resource, defined in
Public Resources Code Section 21074 as either a
site, feature, place, cultural landscape that is
geographically defined in terms of the size and
scope of the landscape, sacred place, or object with
cultural value to a California Native American tribe,
and that is
i) Listed or eligible for listing in the California Register
of Historical Resources, or in a local register of
historical resources as defined in Public Resources
Code Section 5020.1(k); or
X
ii) A resource determined by the lead agency, in its
discretion and supported by substantial evidence,
to be significant pursuant to criteria set forth in
subdivision (c) of Public Resources Code Section
5024.1. In applying the criteria set forth in
subdivision (c) of Public Resource Code Section
5024.1, the lead agency shall consider the
significance of the resource to a California Native
American tribe.
X
Impact Analysis
4.18a.i Would the project cause a substantial adverse change in the significance of a tribal
cultural resource, listed or eligible for listing in the California Register of Historical
Resources, or in a local register of historical resources as defined in Public Resources
Code Section 5020.1(k)?
Less Than Significant Impact. As concluded in Response 4.5a, the Project Site contains two vacant
buildings built in 1982 that are not considered to be historic resources. There are no national,
State, or locally-designated historic resources on the Project Site. Therefore, the Project would
not cause a substantial adverse change in the significance of a tribal cultural resource, listed or
eligible for listing in the California Register, or in a local register of historical resources, and there
would be no impact.
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4.18a.ii Would the project cause a substantial adverse change in the significance of a tribal
cultural resource- a resource determined by the lead agency, in its discretion and
supported by substantial evidence, to be significant pursuant to criteria set forth in
subdivision (c) of Public Resources Code Section 5024.1. In applying the criteria set forth
in subdivision (c) of Public Resource Code Section 5024.1, the lead agency shall consider
the significance of the resource to a California Native American tribe?
Less Than Significant With Mitigation Incorporated. Chapter 532 Statutes of 2014 (i.e., AB 52)
requires that lead agencies evaluate a project’s potential impact on “tribal cultural resources,”
which include “[s]ites, features, places, cultural landscapes, sacred places, and objects with
cultural value to a California Native American tribe that are eligible for inclusion in the California
Register of Historical Resources or included in a local register of historical resources.” AB 52 also
gives lead agencies the discretion to determine, based on substantial evidence, whether a
resource qualifies as a “tribal cultural resource.”
SB 18 requires a local government to notify and consult with California Native American tribes
when the local government is considering the adoption or amendment of a general plan or a
specific plan. SB 18 provides California Native American tribes an opportunity to participate in
local land use decisions at an early stage of planning, for the purpose of protecting or mitigating
impacts on cultural places. Prior to the adoption or amendment of a general plan or a specific
plan, a local government must refer the proposed action to those tribes that are on the NAHC
contact list and have traditional lands located within the city or county’s jurisdiction. The referral
must allow a 45-day comment period pursuant to Government Code §65352(b).
In compliance with AB 52 and SB 18, the City provided formal notification to California Native
American Tribal representatives identified by the California NAHC. Results of the Sacred Lands
File Search, provided in Appendix B of the IS/MND, conducted with the NAHC were positive, and
the NAHC recommended further consultation with the Gabrieleno Band of Mission Indians – Kizh
Nation and the Gabrieleno/Tongva San Gabriel Band of Mission Indians. The City contacted the
Tribal representative of the Tribe noted below pursuant to AB 52 and SB 18 requirements on May
16, 2025.
• Gabrieleno/Tongva San Gabriel Band of Mission Indians, Chairperson Anthony
Morales
• Gabrielino-Tongva Tribe, Chairperson Charles Alvarez
• Gabrielino-Tongva Tribe, Cultural Resource Director Sam Dunlap
• Gabrielino Tongva Indians of California Tribal Council, Cultural Resource
Administrator Christina Conley
• Gabrielino Tongva Indians of California Tribal Council, Chairperson Robert Dorame
• Gabrielino/Tongva Nation, Chairperson Sandonne Goad
• Gabrieleño Band of Mission Indians – Kizh Nation, Andrew Salas and Christina
Swindall Martinez
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• Cahuilla Band of Indians, BobbyRay Esparza, Anthony Madrigal, Erica Schenk
• Santa Rosa Band of Cahuilla Indians, Steven Estrada and Vanessa Minott
• Soboba Band of Luiseno Indians, Jessica Valdez and Joseph Ontiveros
The City received a formal request for government-to-government consultation under AB 52
from the Gabrieleño Band of Mission Indians – Kizh Nation on May 27, 2025. To date, no other
responses from the Native American Tribes have been received as part of the AB 52 and SB 18
Tribal consultation effort.
The Gabrieleño Band of Mission Indians – Kizh Nation provided information to the City related to
their ancestral homelands and affiliation to the Project area. The Gabrieleño Band of Mission
Indians – Kizh Nation did not identify Tribal cultural resources on the Project Site. However, the
Gabrieleño Band of Mission Indians – Kizh Nation requested preferred Tribal mitigation measures
be made part of the Project and be implemented during Project construction. As discussed in
Response 4.5b, Kimley-Horn did not identify any archaeological resources within the Project area.
As such, no archaeological resources that meet the definition of “Historical Resources” or
“Unique Archaeological Resources”, as defined by CEQA, have been identified within the Project
area. Therefore, the potential to encounter in-situ remains associated with significant
archaeological materials during Project activities is low. Nevertheless, ground-disturbing
activities have the potential to reveal buried deposits not observed on the surface during
previous surveys. Therefore, the potential exists for the Project to result in a substantial adverse
change in the significance of a previously unidentified Native American Tribal cultural resource.
With implementation of MM TCR-1 through MM TCR-3, potential impacts to tribal cultural
resources would be less than significant.
Mitigation Measures
MM TCR-1 Retain a Native American Monitor Prior to Commencement of Ground-
Disturbing Activities. The Project Applicant shall retain a Native American Monitor
from or approved by the Gabrieleño Band of Mission Indians – Kizh Nation. The
monitor shall be retained prior to the commencement of any “ground-disturbing
activity” for the subject Project at all Project locations (i.e., both on-site and any
off-site locations that are included in the Project description/definition and/or
required in connection with the Project, such as public improvement work).
“Ground-disturbing activity” shall include, but is not limited to, demolition,
pavement removal, potholing, auguring, grubbing, tree removal, boring, grading,
excavation, drilling, and trenching.
A copy of the executed monitoring agreement shall be submitted to the Lead
Agency prior to the earlier of the commencement of any ground-disturbing
activity, or the issuance of any permit necessary to commence a ground-disturbing
activity.
The monitor shall complete daily monitoring logs that will provide descriptions of
the relevant ground-disturbing activities, the type of construction activities
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performed, locations of ground-disturbing activities, soil types, cultural-related
materials, and any other facts, conditions, materials, or discoveries of significance
to the Tribe. Monitor logs shall identify and describe any discovered Tribal cultural
resources, including but not limited to, Native American cultural and historical
artifacts, remains, places of significance, etc., as well as any discovered Native
American (ancestral) human remains and burial goods. Copies of monitor logs
shall be provided to the Project Applicant and Lead Agency upon written request
to the Tribe.
On-site tribal monitoring shall conclude upon the latter of the following (1) written
confirmation to the Kizh from a designated point of contact for the Project
Applicant or Lead Agency that all ground-disturbing activities and phases that may
involve ground-disturbing activities on the Project Site or in connection with the
Project are complete; or (2) a determination and written notification by the Kizh
to the Project Applicant or Lead Agency that no future, planned construction
activity and/or development/construction phase at the Project Site possesses the
potential to impact Kizh Tribal cultural resources.
MM TCR-2 Unanticipated Discovery of Tribal Cultural Resource Objects (Non-
Funerary/Non-Ceremonial). Upon discovery of any Tribal cultural resources, all
construction activities in the immediate vicinity of the discovery shall cease (i.e.,
not less than the surrounding 50 feet) and shall not resume until the discovered
Tribal cultural resource has been fully assessed by the Kizh monitor and/or Kizh
archaeologist. The Kizh shall recover and retain all discovered Tribal cultural
resources in the form and/or manner the Tribe deems appropriate, in the Tribe’s
sole discretion, and for any purpose the Tribe deems appropriate, including for
educational, cultural and/or historic purposes.
MM TCR-3 Unanticipated Discovery of Human Remains and Associated Funerary or
Ceremonial Objects. Native American human remains are defined in PRC 5097.98
(d)(1) as an inhumation or cremation, and in any state of decomposition or skeletal
completeness. Funerary objects, called associated grave goods in PRC Section
5097.98, are also to be treated according to this statute.
If Native American human remains and/or grave goods are discovered or
recognized on the Project Site, then PRC 5097.9 as well as Health and Safety Code
Section 7050.5 shall be followed.
Human remains and grave/burial goods shall be treated alike per PRC Section
5097.98(d)(1) and (2).
Preservation in place (i.e., avoidance) is the preferred manner of treatment for
discovered human remains and/or burial goods.
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Any discovery of human remains/burial goods shall be kept confidential to prevent
further disturbance.
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4.19 Utilities and Service Systems
This Section is based on the Water Service Availability Letter provided by the San Gabriel Valley
Water Company and the Sanitary Sewer Capacity Study prepared by Kimley-Horn, which re
included in Appendix N: Water Service Availability Letter and Appendix O: Sanitary Sewer
Capacity Study, respectively.
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Require or result in the relocation or construction
of new or expanded facilities concerning the following,
the construction or relocation of which could cause
significant environmental effects?
i. Water,
ii. Wastewater,
iii. Wastewater Treatment,
iv. Stormwater Drainage,
v. Electric Power, Natural Gas, and
Telecommunications.
X
b) Have sufficient water supplies available to serve
the project and reasonably foreseeable future
development during normal, dry and multiple dry
years?
X
c) Result in a determination by the wastewater
treatment provider which serves or may serve the
project that it has adequate capacity to serve the
project projected demand in addition to the
provider’s existing commitments?
X
d) Generate solid waste in excess of State or local
standards, or in excess of the capacity of local
infrastructure, or otherwise impair the attainment
of solid waste reduction goals?
X
e) Comply with federal, state, and local management
and reduction statutes and regulations related to
solid waste?
X
Impact Analysis
4.19a.i Would the project require or result in the relocation or construction of new or expanded
facilities concerning water, the construction or relocation of which could cause
significant environmental effects?
Less Than Significant Impact.
During construction, water will be required intermittently for dust control, equipment cleaning,
soil grading and preparation during the early phases of the Project. The latter phases of
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construction normally require less water usage. Since water usage during construction is typically
less demanding than the water usage for the proposed Project, it is anticipated that existing
water infrastructure would meet the limited, temporary water demand associated with
construction of the Project, and that the water purveyor is able to provide water during
construction.
Table 4.19-1: Estimated Water Demand shows the estimated existing water demand for the
Project Site. The existing water demand assumes 120 percent of the Los Angeles County
Sanitation Districts (LACSD) wastewater generation factors. This estimate is appropriate to
account for any additional water demand for possible minor losses on-site, such as water use due
to human consumption (cooking, drinking, watering indoor plants, evaporation), that would
deviate from the LACSD sewage generation factors. As shown below in Table 4.19-1, the Project’s
estimated water consumption is approximately 35,755 gpd, which is less water demand than the
estimated water demand from the existing office building when occupied.
Table 4.19-1: Estimated Water Demand
Land Use Units Estimated Average Daily
Sewage Flow Factor1
Total Water Demand
(gpd)
Proposed Townhomes 191 DU 187.2 gpd/DU 35,755
Existing Office Building 249.7 ksf 240 gpd/ksf 59,928
gpd = gallons per day; DU = dwelling units; ksf = thousand square feet
1. Based on 120 percent of the sewer generation factors from the “Loading for each class of land use” from LACSD.
Additionally, as noted in Appendix N: Water Service Availability Letter, the San Gabriel Valley
Water Company would have sufficient water resources available to supply water service to the
property. For the reasons listed above, the Project would not require or result in the relocation
or construction of new or expanded water facilities. Impacts would be less than significant, and
no mitigation is required.
4.19a.ii Would the project require or result in the relocation or construction of new or expanded
facilities concerning wastewater, the construction or relocation of which could cause
significant environmental effects?
4.19a.iii Would the project require or result in the relocation or construction of new or expanded
facilities concerning wastewater treatment, the construction or relocation of which
could cause significant environmental effects?
Less Than Significant Impact. The City is within the jurisdictional boundaries of the Los Angeles
County Sanitation District (LACSD). There is an existing 15-inch County trunk line that runs south-
east along the southwest corner of the Project Site and a sewer system on the Project Site that
serves the existing buildings. The sewer system drains to an existing manhole at the southwest
corner of the Project Site and connects to the County trunk line through an existing 8-inch
polyvinyl chloride (PVC) sewer line.
The Project would install an 8-inch sewer line that would connect to the existing sewer manhole
at the south-west corner of the Project Site. The proposed sewer would connect to each building
and would run south then west to the existing manhole. The Project would also include a lift
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station at the south-west corner of the Project Site to pump the proposed flow to the existing
manhole. When considering impacts resulting from the installation of any required water
infrastructure, all impacts are of a relatively short-term duration (i.e., weeks to months) and
would cease to occur once the installation is complete. Installation of new or relocation of
existing water infrastructure will be limited to on-site water distribution, and minor off-site work
associated with connections to the public main. No upgrades to public water mains, other than
onsite infrastructure, are anticipated. Before ground disturbance, Project contractors would
coordinate with the City to identify the locations and depth of all lines.
Wastewater from the Project Site would be treated at the A.K. Warren Water Resource Facility
(Warren Facility) in the City of Carson. The Warren Facility, owned and operated by LACSD,
currently provides primary and secondary treatment for a design capacity of 400 million gallons
of wastewater per day (mgd), and an average flow of approximately 246 mgd.79
Construction activities for the Project could result in temporary wastewater generation on-site.
However, such generation would be temporary when compared with the wastewater generated
by the Project. In addition, construction workers would typically utilize portable restrooms and
hand wash areas, which would not contribute to direct wastewater flows to the City’s wastewater
system. Thus, wastewater generation from Project construction activities is not anticipated to
cause any measurable increase in wastewater flows.
Construction impacts associated with wastewater infrastructure would primarily be confined to
trenching for miscellaneous utility lines and connections to public infrastructure. Installation of
wastewater infrastructure will be limited to on-site wastewater distribution and minor off-site
work associated with lateral connections to the existing City sewer main. Any work that may
affect services to the existing sewer lines or impacts to LACSD facilities or plant will be
coordinated with the City’s Public Works Department. Furthermore, construction management
and access plans would ensure safe pedestrian access as well as emergency vehicle access and
safe vehicle travel. Moreover, when considering impacts resulting from the installation of any
required wastewater infrastructure, all impacts are of a relatively short-term duration and would
cease to occur once the installation is complete.
Table 4.19-2: Estimated Wastewater Generation shows the estimated wastewater generation
for the Project Site, based on the LACSD wastewater generation factors.
Table 4.19-2: Estimated Wastewater Generation
Land Use Units Estimated Average Daily
Sewage Flow Factor
Total Wastewater
Generation (gpd)
Proposed Townhomes 191 DU 156 gpd/DU 29,796
Existing Office Building 249.7 ksf 200 gpd/ksf 49,940
gpd = gallons per day; DU = dwelling units; ksf = thousand square feet
As shown in Table 4.19-2, the Project’s projected wastewater generation is approximately 29,796
gpd, which is less wastewater generation than the estimated wastewater generation from the
79 Los Angeles County Sanitation Districts, A.K. Warren Water Resource Facility, https://www.lacsd.org/services/wastewater-
sewage/facilities/ak-warren-water-resource-facility. Accessed October 6, 2025.
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existing office building when occupied. Furthermore, the Project’s estimated wastewater
generation of 29,796 gpd or 0.030 mgd comprises less than 0.012 percent of the wastewater that
is processed daily at the Warren Facility.
For the reasons substantiated above, the Project would not require or result in the relocation or
construction of new or expanded wastewater and wastewater treatment facilities. Impacts
would be less than significant.
4.19a.iv Would the project require or result in the relocation or construction of new or expanded
facilities concerning stormwater drainage, the construction or relocation of which could
cause significant environmental effects?
Less Than Significant Impact. Refer to Response 4.10c concerning drainage patterns and
stormwater drainage systems. As discussed in Response 4.10c, all proposed drainage
improvements would be located within the Project Site. The Project would not require or result
in the relocation or construction of new or expanded off-site stormwater facilities, the
construction or relocation of which could cause significant environmental effects. Therefore, the
Project would result in a less than significant impact in this regard.
4.19a.v Would the project require or result in the relocation or construction of new or expanded
facilities concerning electric power, natural gas, and telecommunications, the
construction or relocation of which could cause significant environmental effects?
Less Than Significant Impact. The City’s electrical power is provided by SCE, and natural gas is
provided by SoCalGas. The City’s telecommunications are provided by various companies. SCE,
SoCalGas, and local telecommunications companies operate and maintain transmission and
distribution infrastructure throughout the City. Refer to Responses 4.6a and 4.6b for further
discussions concerning electricity. The Project would not include any natural gas usage except for
natural gas used to heat the pool and spa. The Project would include on-site connections to
existing telecommunication services. The Project would not require or result in the relocation or
construction of new or expanded off-site electric power, natural gas, or telecommunications
facilities, the construction or relocation of which could cause significant environmental effects.
Therefore, the Project would result in a less than significant impact in this regard.
4.19b Would the project have sufficient water supplies available to serve the Project and
reasonably foreseeable future development during normal, dry and multiple dry years?
Less Than Significant Impact. The San Gabriel Valley Water Company Final 2020 Urban Water
Management Plan and Water Shortage Contingency (UWMP) projects water demands to
increase from 35,578 acre-feet per year (AFY) in 2025 to 37,278 AFY in 2045 for dry years
representing an increase in demand of 1,700 AFY and 36,935 AFY in 2025 to 38,700 AFY in 2045
for normal years representing an increase in demand of 1,765 AFY.80 The proposed water demand
from the Project of 35,755 gpd (40.1 AFY) represents approximately 2.4 percent and 2.3 percent
of the total increase in demand from 2025 to 2045 in the UWMP for dry years and normal years,
80 San Gabriel Valley Water Company, Final 2020 Urban Water Management Plan and Water Shortage Contingency, June 2021,
https://www.sgvwc.com/wp-content/uploads/2021/07/FINAL-San-Gabriel-Valley-Water-Company-2020-UWMP.pdf.
Accessed October 6, 2025.
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respectively, and represents less water demand than the demand associated with the existing
office use on the Project Site. In addition, the volume of water supply required for the Project
does not trigger the requirements for a water supply assessment pursuant to either SB 610 or SB
221. The UWMP also projects adequate supplies to meet all future demands. Additionally, as
provided in Appendix N, San Gabriel Valley Water Company has sufficient water resources
available to supply water service to the Project Site. Therefore, the City would have sufficient
water supplies available to serve the Project, and impacts would be less than significant.
4.19c Would the project result in a determination by the wastewater treatment provider which
serves or may serve the project that it has adequate capacity to serve the project
projected demand in addition to the provider’s existing commitments?
Less Than Significant Impact. As demonstrated in Sections 4.19a.ii and Sections 4.19a.iii, there is
existing treatment capacity in the region for estimated Project wastewater generation. Project
development would not impact LACSD wastewater treatment facility capacity. The Project would
not require or result in the relocation or construction of new or expanded off-site sewer facilities,
the construction or relocation of which could cause significant environmental effects. Therefore,
the Project would result in a less than significant impact in this regard.
4.19d Would the project generate solid waste in excess of State or local standards, or in excess
of the capacity of local infrastructure, or otherwise impair the attainment of solid waste
reduction goals?
4.19e Would the project comply with federal, state, and local management and reduction
statutes and regulations related to solid waste?
Less Than Significant Impact. Republic Services waste haulers provide services in the City,
including the Project Site. The City primarily disposes at landfills throughout Los Angeles County.
Project construction would result in generation of construction and demolition (C&D) debris such
as metal scrap, lumber, concrete which will be collected and diverted to a C&D debris facility for
materials to be recycled and/or discarded. As shown in Table 4.19-3: Estimated Solid Waste
Generation, C&D of the Project is estimated to generate approximately 13,140 tons of C&D
debris. This estimation is a conservative estimate as it assumes that no reductions in waste
generation would occur due to recycling.
Table 4.19-3: Estimated Solid Waste Generation
Land Use Size Waste
Generation Rate
Waste
Generated
(tons)
Waste
Generated (lbs)
Demolition1
Office Building 249.701
ksf 46 tons/ksf 11,486 22,972,492
Central Plant Building 18.314 ksf 46 tons/ksf 842 1,684,888
Construction2
Residences 404.146
ksf 4,020 lb/ksf 812 1,624,667
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Residual wastes such as trash packing materials and plastics could require disposal at landfills.
Disposal and recycling of the construction debris would be required to comply with all federal,
State, and local regulations. All construction activities would be subject to conformance with
relevant Federal, State, and local requirements related to solid waste disposal. The Project would
be required to comply with the California Integrated Waste Management Act of 1989 (AB 939),
which requires that at least 50 percent of waste produced is recycled, reduced, or composted.
As detailed in Table 4.19-3: Estimated Solid Waste Generation, Project operations would
generate approximately 1.2 tons per day (tpd). The estimated amount of solid waste is
conservative because the waste generation factors do not account for recycling or other
diversion measures. The annual amount of solid waste generated by the Project would represent
a minor amount of the estimated 137 million tons of remaining disposal capacity at the County’s
Class III landfills.81 As such, the solid waste generated by the Project would be accommodated by
the landfills that serve the Project Site.
During operation, the Project would be required to comply with CalRecycle’s waste diversion rate
target of 50 percent of the waste stream. The Project would also be subject to AB 1826, which
requires businesses to provide separate recycling bins for organic waste. Therefore, the Project
would be subject to compliance with the CALGreen Code, State regulations, and City regulations
regarding solid waste management and reduction. Impacts would be less than significant.
81 Los Angeles County Department of Public Works, Countywide Integrated Waste Management Plan: 2021 Annual Report,
December 2022, https://dpw.lacounty.gov/epd/swims/ShowDoc.aspx?id=17450&hp=yes&type=PDF. Accessed March 18,
2024.
Total Demolition and Construction Waste 13,140 tons 26,282,047 lbs
Operations3
Residential 191 DU 12.23 lb/DU 1.2 2,336
Total Operational Waste 1.2 tpd 2,336 lbs/day
ksf = thousand square feet; lbs = pounds; tpd = tons per day; DU = dwelling units
1. The demolition waste generation rate of 46 tons/ksf is based on the CalEEMod User Guide Appendix A, page 13.
2. The construction waste generation rate of 4,020 lb/ksf is based on the U.S.EPA, Characterization of Building-Related
Construction and Demolition Debris in the United States, Table A-2, June 1998.
3. Generation factors provided by the CalRecycle website, refer to Estimated Solid Waste Generation Rates,
https://www2.calrecycle.ca.gov/WasteCharacterization/General/Rates. Accessed October 6, 2025.
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4.20 Wildfire
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would
the project:
a) Substantially impair an adopted emergency
response plan or emergency evacuation plan? X
b) Due to slope, prevailing winds, and other factors,
exacerbate wildfire risks, and thereby expose
project occupants to, pollutant concentrations from
a wildfire or the uncontrolled spread of a wildfire?
X
c) Require the installation or maintenance of
associated infrastructure (such as roads, fuel breaks,
emergency water sources, power lines or other
utilities) that may exacerbate fire risk or that may
result in temporary or ongoing impacts to the
environment?
X
d) Expose people or structures to significant risks,
including downslope or downstream flooding or
landslides, as a result of runoff, post-fire slope
instability, or drainage changes?
X
Impact Analysis
4.20a If located in or near state responsibility areas or lands classified as very high fire hazard
severity zones, would the project substantially impair an adopted emergency response
plan or emergency evacuation plan?
4.20b If located in or near state responsibility areas or lands classified as very high fire hazard
severity zones, would the project, due to slope, prevailing winds, and other factors,
exacerbate wildfire risks, and thereby expose project occupants to, pollutant
concentrations from a wildfire or the uncontrolled spread of a wildfire?
4.20c If located in or near state responsibility areas or lands classified as very high fire hazard
severity zones, would the project require the installation or maintenance of associated
infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other
utilities) that may exacerbate fire risk or that may result in temporary or ongoing
impacts to the environment?
4.20d If located in or near state responsibility areas or lands classified as very high fire hazard
severity zones, would the project expose people or structures to significant risks,
including downslope or downstream flooding or landslides, as a result of runoff, post-
fire slope instability, or drainage changes?
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No Impact. See Response 4.9f. According to CAL FIRE, the Project Site is not within or near a SRA
or a VHFHSZ.82 The nearest VHFHSZ is within a Local Responsibility Area (LRA) and is located
approximately 0.7 miles south of the Project Site. The Project Site is relatively flat and developed
with urban uses, which precludes factors such as slopes or strong winds from exacerbating fire
risk. The Project is located on an existing developed site, would connect to existing utilities, and
would not require the installation or maintenance of infrastructure that may exacerbate fire risk.
The Project would be required to comply with design and construction guidelines for internal
emergency circulation, fire lane access, and fire suppression facilities such as sprinkles and fire
hydrants. These would conform with the RMC, and the LACFD would further review Project
development plans prior to approval to ensure adequate emergency access pursuant to Section
503 of the California Fire Code. Post-fire impacts such as drainage changes and landslides would
not occur as the Project Site and its surroundings are highly urbanized, mostly flat, and would not
have any steep slopes or hillsides that would be susceptible to landslides or flooding. Therefore,
the Project would result in no impact related to wildfire.
82 California Department of Forestry and Fire Protection. FHSZ Viewer, https://osfm.fire.ca.gov/what-we-do/community-
wildfire-preparedness-and-mitigation/fire-hazard-severity-zones. Accessed August 8, 2025.
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4.21 Mandatory Findings of Significance
Environmental Issue
Potentially
Significant
Impact
Less Than
Significant With
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Does the Project:
a) Have the potential to substantially degrade the
quality of the environment, substantially reduce the
habitat of a fish or wildlife species, cause a fish or
wildlife population to drop below self-sustaining
levels, threaten to eliminate a plant or animal
community, substantially reduce the number or
restrict the range of a rare or endangered plant or
animal or eliminate important examples of the
major periods of California history or prehistory?
X
b) Have impacts that are individually limited, but
cumulatively considerable? ("Cumulatively
considerable" means that the incremental effects of
a project are considerable when viewed in
connection with the effects of the past projects, the
effects of other current projects, and the effects of
probable future projects.)
X
c) Have environmental effects which will cause
substantial adverse effects on human beings, either
directly or indirectly?
X
Impact Analysis
4.21a Does the project have the potential to substantially degrade the quality of the
environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or
wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or
animal community, substantially reduce the number or restrict the range of a rare or
endangered plant or animal or eliminate important examples of the major periods of
California history or prehistory?
Less Than Significant With Mitigation Incorporated. As discussed throughout this IS/MND, the
Project does not have the potential to degrade the environment’s quality or result in significant
environmental impacts that cannot be reduced to less than significant following compliance with
the established regulatory framework (i.e., federal, State, and local regulations) and the
recommended mitigation measures.
As concluded in Section 4.4: Biological Resources, following compliance with MM BIO-1, which
addresses potential impacts to migratory birds, the Project would substantially reduce the
habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-
sustaining levels, threaten to eliminate a plant or animal community, or substantially reduce the
number or restrict the range of a rare or endangered plant or animal.
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As concluded in Section 4.5: Cultural Resources, the Project would not eliminate important
examples of the major periods of California history. The Project was assessed to have low
sensitivity for prehistoric resources and buried historic archaeological resources. Following
implementation of MM CUL-1 through MM CUL-3, potential impacts to archaeological resources
would be reduced to less than significant.
As concluded in Section 4.7: Geology and Soils, the Project could directly or indirectly cause
potential substantial adverse effects involving rupture of a known earthquake fault and strong
seismic ground shaking, and be located on expansive soil, unless mitigated. Following
implementation of MM GEO-1, potential impacts to geology and soils would be reduced to less
than significant. The Project could potentially destroy a unique paleontological resource or site
or unique geologic feature during construction. Following implementation of MM GEO-2,
potential impacts to paleontological resources would be reduced to less than significant.
As concluded in Section 4.9: Hazards and Hazardous Materials, the Project could 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, unless
mitigated. Following implementation of MM HAZ-1, potential impacts to hazards and hazardous
materials would be reduced to less than significant.
As concluded in Section 4.13: Noise, the Project could generate a substantial temporary or
permanent increase in ambient noise levels in the vicinity of the Project in excess of standards
during Project construction and generate excessive groundborne vibration during construction,
unless mitigated. Following implementation of MM NOI-1 through MM NOI-4, potential impacts
to construction noise and vibration would be reduced to less than significant.
As concluded in Section 4.18: Tribal Cultural Resources, the Project could cause an adverse
change in the significance of a tribal cultural resource, unless mitigated. Following
implementation of MM TCR-1 through MM TCR-3, potential impacts to tribal cultural resources
would be reduced to less than significant.
4.21b Does the project have impacts that are individually limited, but cumulatively
considerable? ("Cumulatively considerable" means that the incremental effects of a
project are considerable when viewed in connection with the effects of the past projects,
the effects of other current projects, and the effects of probable future projects.)
Less Than Significant Impact. The proposed Project would result in significant impacts unless
mitigated for the following environmental resource areas: biological resources, cultural
resources, geology and soils, hazards and hazardous materials, noise, and Tribal cultural
resources. The potential impacts associated with these resource areas are localized, thus, would
not result in cumulative impacts. Other development projects within the City would be subject
to the City’s discretionary review process, CEQA, and the established regulatory framework,
which would be evaluated on a case-by-case basis.
For all other resources areas, the analysis determined the Project would result in either no
impact, less than significant impact following compliance with the established regulatory
framework, and less than significant impact following implementation of mitigation measures.
Therefore, Project impacts would not be cumulatively considerable. The cumulative projects
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would be required to comply with the same or similar thresholds of significance as the Project;
therefore, it is anticipated that the cumulative projects would not individually contribute to a
cumulatively considerable impact. Based on the correspondence with the City, the following
active projects were provided:
• 7801-7825 Garvey Avenue: 92 multi-family DU and 35.548 ksf of strip retail plaza
• 3035 San Gabriel Boulevard: 160 multi-family DU and 73.750 ksf of shopping plaza
• 3001 Walnut Grove Avenue: 32 ksf of commercial uses consisting of office, retail,
restaurants, and a community hall
• 2562 River Avenue: 35.596 ksf of warehousing
• 7539-7545 Garvey Avenue: 75 multi-family DU and 6.436 ksf of non-residential uses
• 909 San Gabriel Boulevard: 3.424 ksf self-service car wash
The projects would each be required to demonstrate consistency with applicable regulations.
Furthermore, none of the projects are in the immediate vicinity of the Project Site. The self-
service car wash is the closest project, approximately 0.5 miles south of the Project Site, and the
other projects are more than one mile away from the Project Site. Therefore, the self-service car
wash is considered to be a cumulative project. Even if the Project were to undergo construction
concurrently with the self-service car wash, the Project would not make a cumulatively
considerable contribution to potential cumulative impacts. Each project would also be required
to, if necessary under CEQA, provide an analysis to determine if the project would result in a
significant impact on the appropriate environmental resource topic areas. Therefore, the Project
would not result in any cumulatively considerable impacts, and no mitigation is required.
4.21c Does the project have environmental effects which will cause substantial adverse effects
on human beings, directly or indirectly?
Less Than Significant Impact. As discussed in the respective sections, the Project would have no
potentially significant impacts that would not be reduced to less than significant following
compliance with the established regulatory framework and/or recommended mitigation
measures. The Project would not cause substantial adverse effects on human beings directly or
indirectly. Therefore, impacts concerning adverse effects on human beings would be less than
significant.