Exhibit A First Addendum to the East-West Connector Project Final Environmental Impact Report - April 2026 (Quarry Lakes Parkway, Phases (Segments) 1-4)

QUARRY LAKES PARKWAY PROJECT
PHASES 1–4, FROM OLD ALAMEDA CREEK TO
MISSION BOULEVARD (SR 238), CITY PROJECT NO.
18-04 IN UNION CITY
First Addendum to the
East-West Connector Project Final
Environmental Impact Report – April 2026
P REPARED FOR :

City of Union City
34009 Alvarado-Niles Road,
Union City, CA 94587
P REPARED BY :

ICF
595 Market Street, Suite 950
San Francisco, CA 94105
ICF. 2026. Quarry Lakes Parkway Project: Phases 1–4, from Old Alameda Creek to Mission Boulevard (SR 238), City Project No. 18-04, First Addendum to the East-West Connector Project Final Environmental Impact Report. April 2026. Union City, CA. Prepared for City of Union City, Union City, CA.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 i April 2026

1. Project Title: Quarry Lakes Parkway Project Phases 1–4: from Old Alameda Creek to Mission Boulevard (SR
238), City Project No. 18-04

2. Lead Agency Name and Address: City of Union City
34009 Alvarado-Niles Road,
Union City, CA 94587

3. Contact Person and Phone
Number:

Marilou Ayupan, Public Works Director
(510) 675-5306
[email protected]

4. Project Location: Between Old Alameda Creek and Mission Boulevard (SR 238) in the city of Union City in
Alameda County, California

5. Project Sponsor’s Name and
Address:

Same as lead agency

6. General Plan Designation: Civic Facility, Station Mixed Use Commercial, Residential (10–17 dwelling units per acre, 17–
30 dwelling units per acre), Open Space, Not
Designated

7. Zoning: Civic Facility (CF), Commercial Station Mixed Use (CSMU), Residential (RM 1500, RM 2500),
Private Institutional (PI), Open Space (OS)

8. Name of Prior CEQA
Document(s):

Alameda County Transportation Authority
East-West Connector (EWC) Project 2009 Final
Environmental Impact Report (EIR)
SCH# 2007102078

9. Description of Project:

The proposed Quarry Lakes Parkway (QLP) Project Phases 1 through 4 (QLP Phases 1–4), from Old Alameda Creek to Mission Boulevard (SR 238), City Project No. 18-04 (project) in Union City would construct a new 0.9-mile roadway alignment in southern Alameda County, California. The project is intended to improve local traffic circulation, bicycle and pedestrian access, transit connectivity, and east–west access between Old Alameda Creek and Mission Boulevard (SR 238) and the realigned Quarry Lakes Drive along Old Alameda Creek. Construction would occur within a corridor that was historically reserved for the realignment of State Route (SR) 84.

The proposed project provides a new four-lane local roadway with landscaped median, bike lanes, sidewalks, or trails along its entire length, creating a continuous bike and pedestrian corridor from Old Alameda Creek to Mission Boulevard with the realigned Quarry Lakes Drive along Old Alameda Creek. The proposed roadway and associated infrastructure improvements are described in detail in the following sections. Project mitigation includes the construction of the earthen portion of a Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 ii April 2026
new section of the Line M Flood Control Channel onsite; the creation and enhancement of seasonal wetland, channel, and riparian habitats; and the preservation of upland annual grassland habitat at a location in the Alameda Creek watershed north of Livermore.

CEQA Addendum No. 1 (this addendum) addresses changes in the project since the adoption of the EWC 2009 EIR.

10. Surrounding Land Uses and Setting:

Open Space, Residential, Mixed-Use and Civic Facility and roadway

11. Required Project Approvals:
 U.S. Army Corps of Engineers: Clean Water Act Section 404 Individual Permit  U.S. Fish and Wildlife Service: Biological Opinion under Section 7 of the federal Endangered Species Act
 California Department of Fish and Wildlife: Streambed Alteration Agreement and Incidental Take Permit
 San Francisco Bay Regional Water Quality Control Board: Clean Water Act Section 401 Water Quality Certification/Waste Discharge Requirements  California Department of Transportation, Caltrans District 4: Encroachment permit for Mission Boulevard (State Route 238)
 Alameda County Flood Control & Water Conservation District: Line M/Old Alameda Creek modifications
 Union Pacific Railroad: Grade Separations at Niles and Oakland Subdivisions  California Public Utility Commission (CPUC): Grade Separations at Niles and Oakland Subdivisions
 Bay Area Rapid Transit (BART): Grade Separation at BART trackway  Alameda County Transportation Commission (Alameda CTC): Regional Planning and Funding
 Metropolitan Transportation Commission (MTC): Regional Planning and Funding  California Transportation Commission (CTC): State Funding  City of Union City: Project approval and funding
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 iii April 2026
Contents

1. Background .................................................................................................... 1-1

1.1 East-West Connector Project Original Development .............................. 1-1

1.2 Union City’s Involvement with Quarry Lakes Parkway............................ 1-3

2. Purpose of the Addendum............................................................................. 2-1

3. Description of Changes Since the EWC 2009 EIR........................................... 3-1

3.1 Project Previously Evaluated in the EWC 2009 EIR.................................. 3-1

3.2 Current Project Overview ........................................................................ 3-8

3.3 Design Changes Since the EWC 2009 EIR............................................... 3-12

4. Evaluation of Environmental Impacts............................................................ 4-1

4.1 Aesthetics................................................................................................. 4-1

4.2 Air Quality ................................................................................................ 4-5

4.3 Biological Resources ................................................................................ 4-7

4.4 Cultural Resources................................................................................. 4-28

4.5 Geological Resources............................................................................. 4-30

4.6 Hazards and Hazardous Materials......................................................... 4-33

4.7 Hydrology and Water Quality ................................................................ 4-35

4.8 Land Use and Planning........................................................................... 4-37

4.9 Noise and Vibration ............................................................................... 4-40

4.10 Population and Housing......................................................................... 4-44

4.11 Public Services and Utilities................................................................... 4-45

4.12 Transportation/Traffic ........................................................................... 4-48

4.13 Cumulative Impacts ............................................................................... 4-55

5. References ..................................................................................................... 5-1 Attachment A: Description of Current Quarry Lakes Parkway, Phases 1 to 4 by Phase Attachment B: QLP Phases 1–4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 iv April 2026
Tables
Table Page
Table 3-1. Summary of Project Components Analyzed in the EWC 2009 EIR from Old Alameda Creek to Mission Boulevard (SR 238) ......................................................... 3-3 Table 3-2. Excavation Requirements for Quarry Lakes Parkway, Phases 1 to 4 Compared to Those in the EWC 2009 EIR.................................................................................. 3-32 Table 4-1. Aesthetics Environmental Checklist............................................................................ 4-1 Table 4-2. Air Quality Environmental Checklist........................................................................... 4-5 Table 4-3. Biological Resources Environmental Checklist ........................................................... 4-7 Table 4-4. Changes in Impacts on Sensitive Biological Resources with Quarry Lakes Parkway, Phases 1 to 4 compared to the 2009 EIR1 .................................................. 4-9 Table 4-5. Cultural Resources Environmental Checklist............................................................ 4-28 Table 4-6. Geological Resources Environmental Checklist........................................................ 4-30 Table 4-7. Hazards and Hazardous Materials Environmental Checklist.................................... 4-33 Table 4-8. Hydrology and Water Quality Environmental Checklist........................................... 4-35 Table 4-9. Land Use and Planning Environmental Checklist...................................................... 4-37 Table 4-10. Noise and Vibration Environmental Checklist ........................................................ 4-40 Table 4-11. Population and Housing Environmental Checklist.................................................. 4-44 Table 4-12. Public Services and Utilities Environmental Checklist............................................ 4-45 Table 4-13. Transportation/Traffic Environmental Checklist .................................................... 4-48 Table 4-14. Comparison of Growth Projections at the Time of the EWC 2009 EIR and at Present..................................................................................................................... 4-51 Table 4-15. Cumulative Projects in the QLP Phases 1–4 Project Area from the EWC 2009 EIR and Current Status............................................................................................. 4-58 Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 v April 2026
Figures
Figure Page
Figure 3-1. 2009 East-West Project Alignment and Quarry Lakes Parkway Phases 1–4 Project........................................................................................................................ 3-2 Figure 3-2a. 2009 Project Alignment in Union City ..................................................................... 3-5 Figure 3-2b. 2009 Project Alignment in Union City ..................................................................... 3-6 Figure 3-3. 2009 Project Alignment and Mitigation Area............................................................ 3-7 Figure 3-4. Quarry Lakes Parkway Phases 1–4 Project Overview.............................................. 3-10 Figure 3-5. Quarry Lakes Parkway Phases 1–4 Project Typical Sections................................... 3-11 Figure 3-6. Location of Project Changes Since the Original EIR................................................. 3-13 Figure 3-7. Realignment of Quarry Lakes Drive......................................................................... 3-16 Figure 3-8. Changes Related to Connections to Osprey Drive................................................... 3-17 Figure 3-9. Modification of Lotus Pond Common Intersection with Alvarado-Niles Road ....... 3-18 Figure 3-10. Existing Box Culvert and Maintenance Road......................................................... 3-20 Figure 3-11. 7th Street Bicycle/Pedestrian Trail and Mission Boulevard (SR 238) Bicycle/Pedestrian Trail ........................................................................................... 3-21 Figure 3-12. Water Quality Basin............................................................................................... 3-23 Figure 3-13. Relocated Line M Flood Control Channel.............................................................. 3-25 Figure 3-14. Temporary Transit Facility at City Parking Lot on 11th Street Near Decoto Road During QLP Phase 1 Construction................................................................... 3-26 Figure 3-15. Regional Location of the Offsite Mitigation Area.................................................. 3-28 Figure 3-16. Location of the Offsite Mitigation Area................................................................. 3-29 Figure 3-17. Proposed Offsite Mitigation .................................................................................. 3-30 Figure 3-18. Proposed Offsite Mitigation, Soil Fill, Spoils Location Map................................... 3-31 Figure 4-1. Crotch’s Bumble Bee Habitat Impact Map in the Roadway Project Area ............... 4-14 Figure 4-2. Geological Formations at the Offsite Mitigation Area ............................................ 4-31 Figure 4-3. Traffic Volume Growth Comparison, Study Intersections: AM and PM Peak Hours........................................................................................................................ 4-53 Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 vi April 2026
Figure 4-4. Cumulative Projects in the Project Area (from the EWC 2009 EIR) ........................ 4-57 Figure 4-5. Station District Specific Plan Proposed Land Uses .................................................. 4-59 Figure A-1. Quarry Lakes Parkway Phase 1 Overview .................................................................... 2 Figure A-2. Quarry Lakes Parkway Phase 2 Overview .................................................................... 4 Figure A-3. Quarry Lakes Parkway Phase 3 Overview .................................................................... 6 Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 vii April 2026
Acronyms and Abbreviations
Term Definition
ABAG Association of Bay Area Governments
ACTA Alameda County Transportation Authority
ACTC Alameda County Transportation Commission
BAAQMD Bay Area Air Quality Management District
BART Bay Area Rapid Transit
BMP best management practice
Caltrans California Department of Transportation
CBB Crotch’s bumble bee
CDFW California Department of Fish and Wildlife
CEQA California Environmental Quality Act
CNG compressed natural gas
Corp Yard Corporation Yard
Corps U.S. Army Corps of Engineers
CRHR California Register of Historical Resources
CRLF California red-legged frog
CTS California tiger salamander
EIR environmental impact report
EWC East-West Connector
GHG greenhouse gas
HMMP Habitat Mitigation and Monitoring Plan
I- Interstate
MOU memorandum of understanding
MSAT mobile-source air toxic
NEPA National Environmental Policy Act
NRHP National Register of Historic Places
QLD Quarry Lakes Drive
QLP Quarry Lakes Parkway
QLP Phases 1–4 project Quarry Lakes Parkway Phases 1 through 4 project RCP reinforced concrete pipe
RWQCB Regional Water Quality Control Board
SDSP Station District Specific Plan
UPRR Union Pacific Railroad
USFWS U.S. Fish and Wildlife Service
VMT vehicle miles traveled
WBB western bumble bee
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 1-1 April 2026

1. Background

1.1 East-West Connector Project Original Development
In 1958, the California Department of Transportation (Caltrans) first proposed the State Route (SR) 84 Realignment Project, which would provide a six-lane freeway to connect Interstate (I-) 880 on the west to Mission Boulevard on the east through the cities of Fremont and Union City. In the 1960s and 1970s, Caltrans established a plan line for the project and began purchasing right-of-way along part of the proposed realignment corridor (Historical Alignment). At that time, the project was also included in the Bay Area’s Regional Transportation Plan. In 1980, the California Transportation Commission rescinded the route designation in this portion of the SR 84 corridor after it was determined that no future funding was available for the proposed freeway.

With the completion of the east approach to the Dumbarton Bridge in 1984, the need to upgrade SR 84 in southern Alameda County became critical. Accordingly, Caltrans prepared a Route Concept Report for SR 84 from Santa Cruz to Brentwood. After the SR 84 Realignment Project in Fremont and Union City was included in Alameda County’s half-cents transportation sales tax measure, known as Measure B and approved by voters in 1986, environmental studies for the SR 84 Realignment Project were conducted by Caltrans.

Substantial local opposition prolonged the environmental review process. In 2002, Caltrans and the Federal Highway Administration completed a final combined environmental impact report (EIR)/environmental impact statement for the SR 84 Realignment Project in compliance with the California Environmental Quality Act (CEQA) and National Environmental Policy Act (NEPA), respectively. Local opposition to the project continued, and the Federal Highway Administration was reluctant to certify the document without local consensus.

To address the continuing projected and ongoing traffic congestion problems in the SR 84 area, the Alameda County Transportation Authority (ACTA) took over the lead agency role for the SR 84 Realignment Project from Caltrans in 2002. ACTA worked with the Cities of Fremont and Union City, Caltrans, and local community members and organizations to redefine the purpose of the project and to develop alternative alignment locations that would be acceptable to the local communities. Between 2002 and 2006, ACTA studied several alternative alignment options, selecting Option 2 and Option 4/6 for further study.

After further preliminary design, preparation of environmental constraints studies, and consideration of community input, Option 2 was selected and renamed the East-West Connector (EWC) project. In general, the EWC project includes widening Decoto Road from I-880 to Paseo Padre Parkway, improving Paseo Padre Parkway between Decoto Road and Isherwood Way and constructing a new four-lane roadway parallel to and just south of

1. Background
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 1-2 April 2026
Decoto Road from Paseo Padre Parkway to the Mission Boulevard/Appian Way intersection within a portion of the Historical Alignment originally proposed for the SR 84 Realignment Project in the 1960s and 1970s.

In March 2006, ACTA, Caltrans, and the Cities of Fremont and Union City entered into a memorandum of understanding (MOU) to formalize the commitment of funding and define the roles and responsibilities in their coordination on defining the new alignment and components of Option 2 for the EWC. Effective May 25, 2006, the MOU allowed ACTA to perform additional preliminary engineering on Option 2, and to evaluate its benefits and potential impacts before a final implementation decision is made.

In addition to identifying Option 2 as the proposed EWC alignment, the MOU set the framework for AB1462 allowing proceeds of sale of the state-owned land for the Historical Route 84 corridor to be used to fund other transportation projects in Southern Alameda County including Quarry Lakes Parkway.

CEQA Process for the East-West Connector
In October 2006, ACTA, as the lead agency, issued a Notice of Preparation to prepare an EIR for the EWC in compliance with CEQA. Caltrans and the Cities of Fremont and Union City served as responsible agencies throughout the CEQA process. The EIR addressed the MOU requirements pertaining to the environmental process for the EWC and three project alternatives:
 EIR Alternative 1: Historical Alignment in Union City  EIR Alternative 2: Previously Studied Transportation System Management  EIR Alternative 3: No Project
Alternative 1 represented the truncated version of the EWC required by the MOU and was analyzed at the same level of detail as the EWC in the EIR. ACTA distributed the Notice of Preparation to prepare the EIR for a 30-day review and comment period from October 12 to November 12, 2007. The Draft EIR was circulated for public review from December 11, 2008, to February 9, 2009. Public hearings on the Draft EIR were held on January 14 and 15, 2009. ACTA certified the Final EIR on May 28, 2009, and approved the EWC on June 25, 2009.
1 On December 30, 2009, the California Transportation Commission (CTC) approved the State Route 84 Local Alternative Transportation Improvement Program (LATIP) in Southern Alameda County. The approval included a list of LATIP project to be funded with the 1 In June and July 2009, per Resolutions 3816-09 and 3838-09, the City of Union City, as a responsible agency, made a finding that the EIR was complete and in compliance with CEQA, concurred with the CEQA findings, and approved the project for its part.

1. Background
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 1-3 April 2026
proceeds of the sale of excess state-owned parcels, which included the East West Connector project (LATIP Project No. 4).

In July 2010, The Alameda County Transportation Commission (Alameda CTC) was created with the merger of Alameda County Congestion Management Agency (ACCMA) and ACTA to streamline operations, eliminate redundancies and save taxpayers’ dollars. Alameda CTC is able to implement more cost-effective methods for planning, funding, and delivering programs and projects that benefit Alameda County residents and businesses.

The EWC Final EIR Volume I (Main Text) is available on the Alameda CTC website (ACTA 2009; see link in Section 5, References).

1.2 Union City’s Involvement with Quarry Lakes Parkway
On March 22, 2018, Alameda CTC approved the East West Connector Project/Programming and Project Delivery Strategy by executing a Funding Agreement (PFA) No. A18-0046 in the amount of $2.5 million with the City of Union City which transferred the project delivery responsibilities to the city. In general, the PFA identified the following:
1) Union City will take over as lead agency for the CEQA document 2) Union City is the implementing agency responsible for the redesign of the East West Connector project to current multimodal policies and Complete Streets design criteria and update project estimates.
3) Union City to evaluate the need for the update of the traffic study in the EIR from the Dumbarton Bridge to the Union City BART Station and determine whether an update, amendment or addendum to the EIR is required
On February 12, 2019, the City Council of Union City under Resolution No. 5444-19 authorized the renaming of the East West Connector to the Quarry Lakes Parkway (QLP) from Paseo Padre Parkway in Fremont to Mission Boulevard (SR 238) in Union City to serve as the gateway to Quarry Lakes Regional Park with support from East Bay Regional Park District.

On July 9, 2019, the City Council of Union City adopted Resolution No. 5504-19 declaring a Public Purpose and Authoring the City Manager to execute a Purchase and Sale Agreement (PSA) with the Caltrans Department of Transportation for the purchase of the certain excess Route 84 properties in Union City. These excess Caltrans parcels approximately 35 acres are bound by Old Alameda Creek, Osprey Drive, Alvarado-Niles Road, and Fremont city limits.

Kittelson & Associates prepared the Quarry Lakes Parkway Transportation Trends Memorandum dated June 2020 to assess and document the land use and transportation trends related to the proposed Quarry Lakes Parkway in comparison to the former EWC

1. Background
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 1-4 April 2026
project from I-880 in Fremont to Mission Boulevard (SR238) in Union City. In summary, the result of the memorandum determined that QLP meets the needs documented in the approved EWC while supporting multimodal land-use plans and project. These reports and documents are on the Quarry Lakes Parkway website
(https://www.unioncityca.gov/499/Quarry-Lakes-Parkway-Project).

On November 19, 2020, Alameda CTC approved the Alameda CTC PFA No. A22-0053 with the City of Union City to complete the Final Design of Quarry Lakes Parkway (East West Connector). Phase 1 and 2 in the amount of $4.2 million. Because of the need to redesign to Complete Streets design standards, the engineering challenges and the robust public outreach, the PFA though Amendments 1–4 has been increased to about $9.0 million to complete the Final PS&E (Plans, Specification and Estimate) for Phases 1 and 2 ready for advertisement. With the unused funds from the previous PFA No. A18-0046, the City completed the 35% Preliminary Design of Quarry Lakes Parkway, Phase 3 and 4 (Grade Separations).

On June 24, 2021, the California Transportation Commission approved Reference No. 2.4c (d), the conveyance of the excess state-owned property to the City of Union City for residential development and for Quarry Lakes Parkway improvements. The appraised value of the state-owned property was estimated at about $86 million.

Quarry Lakes Parkway is funded with transportation funds administered through Alameda CTC including 1986 Measure B, 2014 Measure BB and other transportation funds. The project is identified in Alameda CTC’s 2014 Transportation Expenditure Plan (TEP) and the 2020 Countywide Transportation Plan (CTP) as ID No. 90, Quarry Lakes Parkway (Segments 1–4).

Quarry Lakes Parkway is also funded with Regional Measure 3 (RM3) toll funds under the Dumbarton Corridor Improvement Program, Project No. 17.5-Quarry Lakes Parkway administered through Metropolitan Transportation Commission (MTC). Also, the project is identified in the Bay Area regional transportation plan, Plan Bay Area 2050 as Project No. 79 with a Transportation Improvement Program (TIP) ID No. ALA978004.

The City of Union City is proceeding with completing the Final PS&E for Quarry Lakes Parkway (QLP) Phases 1 and Phase 2 for construction followed by Quarry Lake Parkway, Phase 3 and Phase 4 when funding becomes available. from Old Alameda Creek to Mission Boulevard (SR 238), City Project No. 18-04 (QLP Phases 1–4 project).

The project would construct a new 0.9-mile four-lane roadway alignment with landscape medians, bike lanes, sidewalks, or trails along its entire length; and associated infrastructure improvements, as described in detail in the following sections.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 2-1 April 2026

2. Purpose of the Addendum
CEQA recognizes that one or more of the following types of changes may occur after certification of an EIR that may trigger the need for further environmental review if the changes result in new or substantially more severe significant impacts than disclosed in the certified EIR due to one or more of the following:
 The scope of the project may change;
 The environmental setting in which the project is located may change;  Certain environmental laws, regulations, or policies may change; and/or  Previously unknown information may arise.

CEQA requires a lead agency to evaluate these changes and determine whether they result in new or substantially more severe significant impacts than disclosed in a previously certified environmental document.

The State CEQA Guidelines (Section 15162) describe a process for determining whether a subsequent EIR is warranted:

When an EIR has been certified or a negative declaration adopted for a project, no subsequent EIR shall be prepared for that project unless the lead agency determines, on the basis of substantial evidence in the light of the whole record, one or more of the following:
 Substantial changes are proposed in the project that require major revisions to the previous EIR or negative declaration because of the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects;
 Substantial changes will occur with respect to the circumstances under which the project is undertaken, which will require major revisions to the previous EIR or negative declaration because of the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or  New information of substantial importance, which was not known and could not have been known with the exercise of reasonable diligence at the time the previous EIR was certified as complete or the negative declaration was adopted, shows any of the following:
o The project will have one or more significant effects not discussed in the previous EIR or negative declaration;
o Significant effects previously examined will be substantially more severe than shown in the previous EIR;

2. Purpose of the Addendum
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 2-2 April 2026
o Mitigation measures or alternatives previously found not to be feasible would in fact be feasible and would substantially reduce one or more significant effects of the project, but the project proponents declined to adopt the mitigation measure or alternative; or
o Mitigation measures or alternatives that are considerably different from those analyzed in the previous mitigated negative declaration would substantially reduce one or more significant effects on the environment, but the project proponents declined to adopt the mitigation measure or alternative.

The State CEQA Guidelines (Section 15164(e)) state that a brief explanation of the decision not to prepare a subsequent EIR, pursuant to Section 15162, should be included in an addendum to an EIR, the lead agency’s findings on the project, or elsewhere in the record.

The explanation must be supported by substantial evidence.

The QLP Phases 1–4 project would include design refinements and minor alignment modifications relative to the previously approved EWC project that were not analyzed in the EWC 2009 EIR, resulting in the need for this addendum. Section 3.3, Design Changes Since the EWC 2009 EIR, identifies and describes these modifications. For the purposes of this addendum, the environmental analysis does not differentiate between Phases 1 through

4.This addendum also evaluates whether changed circumstances have occurred in the project area since certification of the EWC 2009 EIR that may result in new significant impacts or substantially more severe significant impacts than those disclosed in the EWC 2009 EIR.

This addendum presents substantial evidence demonstrating that none of the triggers for a subsequent or supplemental EIR under State CEQA Guidelines Section 15162 are met. First, the refinements included in the revised project do not constitute substantial changes that would result in new significant environmental effects or substantially increase the severity of impacts previously identified in the EWC 2009 EIR. Second, the circumstances under which the project would be constructed and operated have not changed in a manner that would introduce new or more severe significant environmental impacts. Third, no new information of substantial importance has become available that would (a) reveal new significant impacts, (b) show that previously identified impacts would be substantially more severe, or (c) identify feasible mitigation measures or alternatives not previously evaluated, but the project proponents decline to adopt the mitigation measure or alternative. As such, preparation of a subsequent or supplemental EIR is not required.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-1 April 2026

3. Description of Changes Since the EWC 2009 EIR

3.1 Project Previously Evaluated in the EWC 2009 EIR
The original project evaluated in the EWC 2009 EIR included a 3.0-mile roadway that would provide improved east–west access between I-880 on the west and Mission Boulevard (SR238) on the east. The original project was designed to Caltrans Expressway design criteria, entailed widening existing roadways and constructing a new roadway segment along with bike lanes, sidewalks, and/or trails, new or modified traffic signals, landscaping, along its entire length in order to provide a continuous bike and pedestrian corridor, improve local circulation and transit operations for Dumbarton Express and Union City Transit from east of I-880 to Mission Boulevard (SR238).

The original 3.0-mile alignment would have extended from the Decoto Road/Cabrillo Court intersection (just northeast of the I-880/Decoto Road ramps) to the Mission Boulevard (SR 238) intersection. The project alignment analyzed in the EWC 2009 EIR included 1.7 miles of improvements to existing roadway segments and 1.3 miles of new roadway and other infrastructure improvements. Table 3-1 lists the project components analyzed in the EWC 2009 EIR. Because the EWC project footprint is much larger than that of the QLP Phases 1–4 project (extending along Paseo Padre Parkway and Decoto Road all the way to I‑880), Table 3-1 addresses only those elements of the EWC within Union City that overlap with the QLP Phases 1–4 project footprint.

Figure 3-1 compares the EWC to the QLP Phases 1–4 project. The original alignment plans from the EWC 2009 EIR are shown on Figures 3-2a and 3-2b. Figure 3-3 depicts the project alignment along with the surrounding plant communities, habitats, and the previously proposed mitigation area.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-2 April 2026
Figure 3-1. 2009 East-West Project Alignment and Quarry Lakes Parkway Phases 1–4 Project

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-3 April 2026
Table 3-1. Summary of Project Components Analyzed in the EWC 2009 EIR from Old Alameda Creek to Mission Boulevard (SR 238)
New Roadway and Other Infrastructure Improvements
New or Modified Roadways
Quarry Lakes Parkway Construct 0.9 mile of new four-lane roadway from Old Alameda Creek to Mission Boulevard (SR 238).

Quarry Lakes Drive Realignment of QLD approximately 450 feet to the southwest (old roadway to be removed).

Osprey Drive from Towhee
Court to Alvarado-Niles
Road
Construct sidewalk and rehabilitate pavement.

Alvarado-Niles Road from
Osprey Drive to Lotus
Pond Common
Reconstruct Alvarado-Niles Road to match new QLP
elevation and undergrounding existing overhead utilities.

New or Improved Intersections
Quarry Lakes Drive/Quarry
Lakes Parkway
New intersection with QLP.

Alvarado-Niles
Road/Osprey Drive
Signal modification at existing intersection. Signal
adjusted/re-timed.

Alvarado-Niles
Road/Quarry Lakes
Parkway
New intersection. Turning lanes and signals to be provided.

Alvarado-Niles Road/Lotus
Pond Common
Modify existing intersection and signalize.
11th Street/Quarry Lakes
Parkway
New intersection. Turning lanes and signals to be provided. 7th Street/Quarry Lakes
Parkway
New intersection with realigned 7th Street/Chesapeake
Drive. Turning lanes and signals to be added.

Mission Boulevard/Quarry
Lakes Parkway
Intersection modification at Mission Boulevard and Appian Way. New turn lanes added. Signal adjusted/re-timed.

Other Project Features
Silva Farmhouse
Demolition
Demolition of an existing single-family residence and barn southwest of the proposed alignment and intersection of Alvarado-Niles Road.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-4 April 2026
New Roadway and Other Infrastructure Improvements
Rail and Road Grade
Separation
Addition of three grade-separation structures for new
roadway alignment extending beneath Bay Area Rapid
Transit (BART), Union Pacific Railroad (UPRR) Oakland
Subdivision, and UPRR Niles Subdivision.

Removal of Detention
Basins
Removal of two detention basins (New Basin and Basin 2C) between Alvarado-Niles Road and Mission Boulevard (SR
238).

Line M Channel and
Diversion Pipeline
Fill of existing Line M Flood Control Channel from north of Chesapeake Court to west of the Corporation Yard (Corp
Yard) and replacement with box culverts along north side of QLP. Installation of drainage bifurcation facilities at Chesapeake Drive and new 84-inch buried pipeline on the south side of the new roadway to Old Alameda Creek.

Modifications to 7th Street
and Corp Yard
Realignment of 7th Street, reconfiguration of compressed natural gas refueling island, and replacement parking for the Corp Yard and Drigon Park.

Onsite Wetlands
Mitigation Site
Creation of a wetlands mitigation site along Old Alameda Creek to compensate for loss of wetlands and riparian
vegetation.

Trail System Upgrades and
Maintenance
Construction of a multi-use path on the north side of the new roadway; new trail segments at new bridge abutments and in Fremont.

Utility Relocation and
Construction
Undergrounding existing utility poles and lines on AlvaradoNiles Road; existing storm drains and drainage inlets to be relocated or modified.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-5 April 2026
Figure 3-2a. 2009 Project Alignment in Union City
Source: ACTC 2009 (EIR for East West Connector, Figure 2-1c)

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-6 April 2026
Figure 3-2b. 2009 Project Alignment in Union City
Source: ACTC 2009 (EIR for East West Connector, Figure 2-1d)

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-7 April 2026
Figure 3-3. 2009 Project Alignment and Mitigation Area
Source: ACTA 2009 (EIR for the East-West Connector, Figure 3.3-1a)

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-8 April 2026

3.2 Current Project Overview
The proposed QLP roadway from Old Alameda Creek to Mission Boulevard (SR 238) was redesigned to meet multimodal policies and Complete Streets design criteria and would include a 0.9-mile four-lane roadway alignment in southern Alameda County, California as originally proposed (Figure 3-1). Union City redesigned Quarry Lakes Parkway as a local four-lanes roadway with landscaped median, Class II buffered bike lanes, sidewalk and a separated Class I multiuse trail. The City has redefined the segments or phases of Quarry Lakes Parkway for project delivery and implementation within the city limits from Old Alameda Creek (Fremont city limits) to Mission Boulevard (SR 238) based on usable segments, available funding, minimum disruption to local traffic circulation and minimum impacts to adjacent neighborhoods and parks.

The project is intended to improve local traffic circulation, bicycle and pedestrian access, transit connectivity, and east–west access between Old Alameda Creek to Mission Boulevard (SR238). Construction would occur within a corridor that was historically reserved for the realignment of SR 84. The project would include bike lanes, sidewalks, or trails along its entire length, creating a continuous bike and pedestrian corridor from the realigned QLD to Mission Boulevard (SR 238). The QLP Phases 1–4 project would be constructed in phases (Phase 1: 2027 to 2030; Phase 2: 2027 to 2029; Phase 3: 2030 to 2032; Phase 4: 2033 to 2034; offsite mitigation: 2026 to 2027).

Phases 1–4 of the project are described as follows:

Quarry Lakes Parkway, Phase 1 (7th Street Connector)
This phase would include construction of a new QLP four-lane roadway between 7th Street and Mission Boulevard (SR 238) with a landscaped median, buffered Class II bike lanes, a sidewalk on one side of the road, and a separated Class I multi-use trail on the opposite side of the road. It would include realignment of 7th Street northeast of the Corp Yard and creation of a new intersection with Chesapeake Drive.

The Line M Flood Control Channel would be realigned with a box culvert under QLP and open channel along the Corp Yard. The new right of way needed for new QLP and the realigned Line M Flood Control Channel would require relinquishment and/or acquisition of properties owned by Alameda County and City of Union City.

This phase would also include the installation of a gravity flow Line M Overflow Pipeline from Line M Channel to Alvarado Niles-Road.

Additional improvements would include relocation and reconstruction of the Corp Yard security wall and construction of a new parking lot adjacent to Drigon Dog Park for use by both the Corp Yard and the dog park.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-9 April 2026
This phase would also include improvement to Mission Boulevard (SR 238) with a new Class I multi-use trail from Holly Leaf Drive to QLP.

Finally, this phase would include a new traffic signal at QLP/Chesapeake Drive intersection and modification of the QLP/Mission Boulevard intersection.

Quarry Lakes Parkway, Phase 2 (Gateway Connection)
This phase would include construction of a new QLP four-lane roadway between Old Alameda Creek and Alvardo Niles with a landscaped median, buffered Class II bike lanes, a sidewalk on one side of the road, and a separated Class I multi-use trail on the opposite side of the road. This phase would also include realignment of Quarry Lakes Drive (QLD) between Isherwood Way in Fremont and QLP, improvements to Alvarado Niles Road between Osprey Drive and Niles Boulevard, and improvements to Osprey Drive from north of Arroyo Park to Alvarado Niles Road. This phase would also include construction of a new traffic signals at QLP/Alvarado Niles Road and Lotus Pond Common/Alvarado Niles Road intersections and modification of the existing traffic signal at Osprey/Alvarado Niles Road.

This phase would also include construction of a new water quality treatment basin adjacent to Old Alameda Creek and Pump Station #2.

Quarry Lakes Parkway, Phase 3 (11th Street Connection)
This phase would include construction of a new QLP four-lane roadway between 7th Street and 11th Street with a landscaped median, buffered Class II bike lanes, a sidewalk on one side of the road, and a separated Class I multi-use trail on the opposite side of the road. This phase would include construction of the new roadway, retaining walls, a new grade separation under the UPRR Niles Subdivision rail line, and modification of the existing Green Street bridge. This phase would also include construction of a new pump station (Pump Station #1) near the intersection of 11th Street and the new QLP roadway.

Quarry Lakes Parkway, Phase 4 (Gateway Connection)
This phase would include construction of a new QLP four-lane roadway between AlvaradoNiles Road and 11th Street with a landscaped median, buffered Class II bike lanes, a sidewalk on one side of the road, and a separated Class I multi-use trail on the opposite side of the road. This phase would include construction of the new roadway, retaining walls and new grade separation structures under the BART trackway and the UPRR Oakland Subdivision.

Additional detail on the changes in the roadway and associated infrastructure improvements compared to that in the EWC 2009 EIR is provided in the following sections, and a further summary of the QLP Phases 1–4 project is provided in Attachment A.

Figure 3-4 shows an overview of the QLP Phases 1–4 project and the project phases.

Figure 3-5 shows typical sections for the project.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-10 April 2026
Figure 3-4. Quarry Lakes Parkway Phases 1–4 Project Overview

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-11 April 2026
Figure 3-5. Quarry Lakes Parkway Phases 1–4 Project Typical Sections

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-12
April 2026

3.3 Design Changes Since the EWC 2009 EIR
Summary Description of Changes
As previously discussed, the project design has changed over time from Caltrans Expressway Design criteria per Highway Design Manual (HDM) to current multimodal policies and Complete Streets design criteria for a local roadway project. The QLP Phases 1–4 project, as currently understood,
2 would differ from the original project analyzed in the EWC 2009 EIR in the following ways (see the locations of changes on Figure 3-6).

Roadway Changes

1. QLD would be realigned slightly to the north where it connects to and confirms with the existing QLD compared to the roadway alignment in the EWC 2009 EIR.

2. The street connection from QLD to Osprey Drive would be eliminated. Osprey Drive street section would be upgraded and a new sidewalk on the east side of Osprey Drive would be constructed to the intersection with Alvarado-Niles Road. A trail connection would still be included from Arroyo Park to the intersection of QLD and QLP.

3. Lotus Pond Common intersection at Alvarado-Niles Road just west of the Niles Road Overhead bridge would be realigned on the approach to the intersection.

4. An existing Line M concrete box culvert that serves as a maintenance road east of Chesapeake Court and south of existing 7th Street would be removed and daylighted requiring the reconstruction of the Line M channel embankments

5. A bicycle/pedestrian trail would be added on the east side of the realigned 7th Street from QLP to the existing emergency vehicle access open space to provide new pedestrian and bike connection for Foothill Glen neighborhood across the Corp Yard.

6. A bicycle/pedestrian trail would be added on the west side of Mission Boulevard from QLP north to Holly Leaf Lane at the gateway entrance of the Foothill Glen neighborhood. 2 Please note that Phases 1 and 2 are at a more detailed level of design as of Quarter 1 2026. Phases 3 and 4 are at an earlier level of design and therefore there may be additional changes relative to the project description as presented in the EWC 2009 EIR; as those are identified during later design phases, the City of Union City will review whether preparation of an additional addendum or other CEQA compliance is necessary.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-13
April 2026
Figure 3-6. Location of Project Changes Since the Original EIR

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-14
April 2026
Drainage Infrastructure Changes

7. A 2-foot concrete wall would be constructed on the existing outfall concrete pad from Old Alameda Creek to the Alameda Creek Flood Control Channel.

8. The EWC 2009 EIR discussed a planned water quality treatment basin and a hydromodification basin but did not identify specific locations. In the current design, a new water quality treatment basin would be located between the realigned QLD and Old Alameda Creek. The outfall from the new water quality basin would discharge to Old Alameda Creek through a combined outfall shared with the Line M Overflow Pipeline.

Hydromodification control for the project would be provided by the existing, underutilized channel capacity of Old Alameda Creek.

9. The existing Line M from Chesapeake Court to west of the City of Union City’s Corporation Yard (Corp Yard) would be filled and replaced with culverts under QLP and in a new earthen channel west of the realigned 7th Street. The new earthen Line N Flood Control channel would encroach into the Corp Yard site, requiring the reconstruction of the Corp Yard security wall and the need for a temporary offsite transit facility during construction. The impacted Corp Yard site would need to be reconfigured to accommodate the transit operations and parking area for Union City and Dumbarton Express fleet.

10. The planned 84-inch Line M Overflow Pipeline is no longer needed as a bypass system for the Line M Flood Control Channel. The pipeline now serves as an overflow system and is called the Line M Overflow Pipeline. The 84-inch pipeline has been reduced to a 60-inch pipeline, which would allow the Line M Flood Control Channel to release stormwater flow after peak storm events. In addition, the outfall location has shifted from the onsite mitigation area in the EWC 2009 EIR to a combined outfall to Old Alameda Creek along with the outfall from the water quality basin (see Final Drainage Report [HDR 2024]).

Mitigation for Waters/Wetlands/Riparian Effects

11. Mitigation for impacts on waters, wetlands, and riparian areas is now proposed at an offsite location within the Alameda Creek watershed near Livermore instead of adjacent to Old Alameda Creek as in the EWC 2009 EIR. The earthen portion of the realigned Line M Flood Control Channel would also provide partial mitigation on site.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-15
April 2026
Detailed Description of Changes
Roadway Design Changes
As previously discussed, the QLP Phases 1–4 project includes roadway design changes that were not analyzed in the EWC 2009 EIR. The roadway design for the QLP Phases 1–4 project differs in the following ways (see Figure 3-6 for locations of changes). 1) Minor Realignment of Quarry Lakes Drive
QLD would be in the same general corridor alignment as shown in the EWC 2009 EIR but would be realigned 50 to 100 feet to the east to accommodate a proposed water quality basin. In the EWC 2009 EIR, the realigned QLD included a multi-use path on the south side of the road and a sidewalk on the north side. The current design would include a multi-use path and a maintenance road . The refined alignment is shown on Figure 3-7. 2) Changes Related to Connections to Osprey Drive
In the EWC 2009 EIR, QLD was proposed to be realigned southward with two options for connecting to QLP. Under both options, QLD would be shifted southwest to meet QLP near Old Alameda Creek, Osprey Drive would be closed from Skylark Drive to Alvarado-Niles Road, and the Osprey Drive connection to Alvarado-Niles Road would be eliminated. Under Option 1, the realigned QLD would terminate at QLP to create a new three‑way intersection while retaining the existing connection of QLD from QLP to Osprey Drive. Under Option 2, the realigned QLD would extend north to connect to Osprey Drive, creating a new four‑way intersection. It was subsequently determined that elimination of the Osprey Drive connection to Alvarado-Niles Road would result in operational issues. As a result, the project now proposes to maintain the existing Osprey Drive/Monterra Terrace//AlvaradoNiles Road signalized intersection and to eliminate any roadway connection between QLD and Osprey Drive, while including a trail connection from QLD to Osprey Drive through Arroyo Park, as shown on Figure 3-8. There would also be minor improvements on Osprey Drive including pavement reconstruction and a new sidewalk along the east side of Osprey Drive to the intersection with Alvarado-Niles Road. At the Monterra Terrace/Osprey Drive/ Alvarado-Niles Road intersection, there would be modifications to the existing traffic signal system.
3) Modification of Lotus Pond Common Intersection with Alvarado-Niles Road The EWC 2009 EIR did not include improvements to the Lotus Pond Common intersection with Alvarado-Niles Road. The intersection currently includes left-turn lanes in each direction on Alvarado-Niles Road, but is not signalized. The project now proposes to signalize the intersection and realign the northern approach of Lotus Pond Common so that the intersection would be perpendicular instead of on a curve (see Figure 3-9).

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-16
April 2026
Figure 3-7. Realignment of Quarry Lakes Drive

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-17 April 2026
Figure 3-8. Changes Related to Connections to Osprey Drive

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-18 April 2026
Figure 3-9. Modification of Lotus Pond Common Intersection with Alvarado-Niles Road

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-19 April 2026
The revised alignment would require acquisition of approximately 0.2 acre of property owned by Bay Area Rapid Transit (BART).
4) Removal of Existing Access Road Over Line M Flood Control Channel.

There is an existing Line M concrete box culvert that serves as a maintenance road east of Chesapeake Court and just south of existing 7th Street and the proposed QLP is no longer needed. Per Alameda County Flood Control District staff this box culvert crossing be removed; it is no longer needed because access to the channel for maintenance would be provided from the new roadway (QLP). Removal of the concrete box culvert and wing walls at this location would be demolished, daylighted along with reconstructing the embankment to an earthen channel. The removal of the box culvert structure was not included in the project description in the EWC 2009 EIR. The existing box culvert maintenance road crossing is shown on Figure 3-10
5) 7th Street Bicycle/Pedestrian Trail
The 2009 EIR analyzed realignment of 7th Street and bike facilities in the street. The QLP Phases 1–4 project would modify the bicycle/pedestrian trail on the east side of the realigned 7th Street from QLP to the existing emergency vehicle access open space into Foothill Glen neighborhood across from the Corp Yard. The trail is shown on Figure 3-11. 6) Mission Boulevard (SR 238) Bicycle/Pedestrian Trail
A bicycle/pedestrian trail would be added on the west side of Mission Boulevard (SR 238) from QLP north to Holly Leaf Lane to the gateway entrance of the Foothill Glen neighborhood. There is an existing sidewalk in this area that would need to be removed.

The path is shown on Figure 3-11.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-20 April 2026
Figure 3-10. Existing Box Culvert and Maintenance Road

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-21 April 2026
Figure 3-11. 7th Street Bicycle/Pedestrian Trail and Mission Boulevard (SR 238) Bicycle/Pedestrian Trail

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-22 April 2026
Drainage Infrastructure Changes
The following design changes in the drainage infrastructure are included in the currently proposed project.
7) Two-Foot Concrete Weir Wall on the Inlet to the Old Alameda Creek Outfall Old Alameda Creek connects to the Alameda Creek Flood Control Channel in Fremont east of Paseo Padre Parkway through three (3) 48-inch-diameter pipes that extend under the channel embankment. These pipes are fitted with automatic drainage flood gates that were installed in the 1960s to prevent water from the Alameda Creek Flood Control Channel from backing up into Old Alameda Creek A new 2-foot-high concrete weir with a 4-foot opening at its center would be constructed on the existing concrete inlet just upstream of the three outlets to help slow down stormwater flows and reduce erosion to the Old Alameda Creek outfall. The location of the concrete weir is shown on Figure 3-6. This feature was not included in the design in the original EIR.
8) Water Quality Basin
The EWC 2009 EIR discussed the need for a water quality basin to treat roadway stormwater runoff before it discharges into Old Alameda Creek, but did not identify a specific location for that facility. This basin is now proposed to be located next to Old Alameda Creek and south of the realigned QLD (see location on Figure 3-6). It would discharge treated stormwater into Old Alameda Creek through a combined outfall that also serves the Line M Overflow Pipeline (see description below). The water quality basin design plan is shown on Figure 3-12. The EWC EIR also discussed the need for a hydromodification basin to store water during peak storm events, but did not identify a specific location for the basin. The underutilized Old Alameda Creek would be used for the hydromodification basin, which is supported by RWQCB staff, and the creek has abundant capacity as documented in the Final Drainage Report (HDR 2024).

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-23 April; 2026
Figure 3-12. Water Quality Basin

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-24 April 2026
9) Relocated New Line M Flood Control Channel
Line M Flood Control Channel is an existing engineered channelized drainage within the project area from the end of Chesapeake Court until it turns northwest just south of the southeast corner of the Corp Yard. In the EWC 2009 EIR, it was planned to fill in the existing Line M Flood Control Channel from the end of Chesapeake Court to a point near the southeast corner of the Corp Yard and replace it with two 10-foot by 5-foot box culverts placed along the west side of the new roadway, just east of the Corp Yard.

The project still proposes to fill the existing Line M Flood Control Channel from the end of Chesapeake Court to the southeast corner of the Corp Yard. As shown on Figure 3-13, Line M Flood Control Channel is now proposed to be replaced with an underground portion and an aboveground earthen channel west of the existing Line M Flood Control Channel. The underground portion would consist of two 12-foot by 6-foot box culverts from the end of Chesapeake Court beneath the new roadway, existing Corp Yard parking lot, and 7th Street.

The aboveground portion would be an approximately 700-foot earthen channel from south of the realigned 7th Street to the southeast corner of the Corp Yard. The earthen channel would encroach approximately 40 feet to the northwest into the Corp Yard, requiring acquisition of an additional approximately 22,000 square feet of the Corp Yard property (in addition to 21,000 square feet for the 7th Street realignment included in the EWC 2009 EIR).

Union City Transit and Dumbarton Express fleets currently operate and park buses within the southern area of the Corp Yard. Union City Transit fixed-route fleet currently uses compressed natural gas (CNG) buses and has purchased eight (8) fixed route buses to battery electric vehicles and plans to modify the Corp Yard with new electric charging stations along with other operational improvements.

The relocated Line M Flood Control Channel would reduce the overall Corp Yard site and impact the southern area currently used for transit operations and parking. During construction of QLP Phase 1, a temporary transit facility would be located at the city parking lot at 11th Street and Decoto Road, as shown on Figure 3-14. Following completion of QLP Phase 1 construction, the Corp Yard would be reconfigured to accommodate the transit operations, circulation, and the parking area for UC Transit and Dumbarton Express.

The temporary relocation of the Union City Transit fleet and changes to the configuration of the Corp Yard transit operations, circulation, and parking area are components of the QLP Phases 1–4 project, as realignment of Line M Flood Control Channel would encroach into the existing Corp Yard. The City may separately consider expansion of the Corp Yard to the north as part of a future project; however, such expansion is not required to implement the QLP Phases 1–4 project.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-25 April 2026
Figure 3-13. Relocated Line M Flood Control Channel

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-26 April 2026
Figure 3-14. Temporary Transit Facility at City Parking Lot on 11th Street Near Decoto Road During QLP Phase 1 Construction

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-27 April 2026
10) Line M Overflow Pipeline and Outfall
As included in the EWC 2009 EIR, the Line M Overflow Pipeline (then referred to as the “new diversion pipeline”) was planned to be an 84-inch pipeline, and its outfall to Old Alameda Creek would be a new open channel within the then-proposed onsite wetland mitigation site. The Line M pipeline is no longer needed as a bypass system and now serves as an overflow system for the Line M Flood Control Channel during peak storm events, which is discussed in the Final Drainage Report (HDR 2024). The Line M Overflow Pipeline diameter has therefore been reduced to 60 inches, with an outfall in Old Alameda Creek approximately 100 feet southwest of the new intersection of QLP and the realigned QLD.

The outfall would serve as a combined discharge point for both the Line M Flood Channel overflow pipeline and treated water from the water quality basin. The outfall would include construction of a headwall, wingwalls, flap gates, and rock slope protection. The location of the outfall to Old Alameda Creek is shown on Figure 3-6.

Offsite Mitigation
11) Offsite Mitigation
The EWC 2009 EIR included a proposed mitigation area for wetlands, waters, and riparian habitat along a new drainage area that would be constructed north of and adjacent to Old Alameda Creek, west of the realigned QLD. Subsequent investigation determined this was not a feasible mitigation approach. Although the relocated Line M Flood Control Channel would continue to provide partial onsite mitigation, as previously included in the EWC 2009 EIR, the project now also proposes offsite mitigation within the Alameda Creek watershed.

The project would permanently fill 1.1 acres of wetlands, 0.4 acre and 1,421 linear feet of channel (Line M Flood Control Channel), and 0.3 acre of riparian vegetation. A portion of these impacts would be mitigated on site through the earthen portion of the new Line M Flood Control Channel (712 linear feet; 0.65 acre). The remaining mitigation would occur at the offsite mitigation property within the Alameda Creek watershed north of Livermore and would include approximately 3.4 acres of wetlands, approximately 1,800 linear feet of channel, and approximately 1 acre of riparian vegetation.

Habitat creation and restoration at the mitigation property would provide compensatory mitigation for project impacts through establishment of new drainage features, seasonal wetlands, and riparian habitat, in addition to enhancement of existing riparian habitat and preservation of existing annual grassland habitat. The regional location of the proposed offsite mitigation area is shown on Figure 3-15, the detailed location is shown on Figure 3- 16, the proposed mitigation is shown on Figure 3-17, and proposed soil fill/spoils locations are shown on Figure 3-18.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-28 April 2026
Figure 3-15. Regional Location of the Offsite Mitigation Area

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-29 April 2026
Figure 3-16. Location of the Offsite Mitigation Area

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-30 April 2026
Figure 3-17. Proposed Offsite Mitigation

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-31 April 2026
Figure 3-18. Proposed Offsite Mitigation, Soil Fill, Spoils Location Map

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-32 April 2026
The proposed mitigation property contains existing aquatic features that would be enhanced as part of the Habitat Mitigation and Monitoring Plan (HMMP) (Olberding 2026) in addition to existing annual grassland habitat where new aquatic features would be constructed. The HMMP, which is incorporated by reference into this addendum, includes information about the mitigation property; objectives for compensatory replacement; implementation specifications, including rationale for expected success; maintenance and monitoring requirements; and contingency measures.

The HMMP is subject to approval by the U.S. Army Corps of Engineers (Corps), U.S. Fish and Wildlife Service (USFWS), California Department of Fish and Wildlife (CDFW), and Regional Water Quality Control Board (RWQCB). In working with the permitting agencies, the HMMP may be further modified somewhat, but the general character of the HMMP in terms of habitats to be created or enhanced will not substantially change.

Excavation and Fill Amounts
Changes in excavation and fill amounts are shown in Table 3-2.

Table 3-2. Excavation Requirements for Quarry Lakes Parkway, Phases 1 to 4 Compared to Those in the EWC 2009 EIR
Project Element
Excavation
(CY) Fill (CY)
Approx. Net Volume
to Be Reused or
Hauled Off Site (CY)
Roadway, Paseo Padre to
Alvarado-Niles Road1
107,000
(no change)
13,000
(no change)
94,000
(no change)
Roadway, Alvarado-Niles Road
to Mission Boulevard2
130,400
153,800
38,000
7,900
92,000
145,900
Roadway, Mission Boulevard 1,400
(no change)
0 (no change)
1,400
(no change)
Onsite Wetland/Waters
Mitigation
230,000 230,000
Offsite Wetland/Waters
Mitigation
11,000 11,000 N/A3
Total at Time of EWC 2009 EIR 468,800 51,000 417,400
Revised Total 273,200 31,900 241,300
Net Change -195,600 -19,100 -176,100
1 This segment would include QLP Phase 5, which would be advanced later and is not the subject of this addendum, as well as Phase 2, which is part of this addendum. 2 This segment would include cut-and-fill quantities related to the Line M Flood Control Channel, including establishment of the new Line M Flood Control Channel.

CY = cubic yards; N/A = not applicable
3 For the offsite mitigation, the two primary sites for soil fill/spoils are on site or immediately adjacent to the mitigation location. There is a third site approximately 1.2 miles from the mitigation area that would be used if the primary sites were not available for some reason.

3. Description of Changes Since the EWC 2009 EIR
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 3-33 April 2026
Due to the revisions to the project, in particular due to the change from the proposed onsite mitigation along Old Alameda Creek for wetlands, waters, and riparian vegetation to implementing wetland, water, and riparian mitigation at the offsite mitigation area, there would be a substantial reduction in excavation, fill, and amounts of material to be reused or hauled off site.

Outreach Conducted for the Quarry Lakes Parkway Phases 1–4 Project Multiple public meetings, events, and City Council formal actions have taken place between 2018 and March 2026 regarding the project. These meetings, hearings, and events have provided the public with opportunities to ask questions, give input, and submit comments on the QLP Phases 1–4 project.
 Twelve City of Union City Bicycle & Pedestrian Advisory Committee (BPAC) Meetings have taken place from 2019 through 2025. These meetings served as the primary forum for public input and comment on the project over the years.  Thirty-five public meetings, presentations, and special outreach events have been held between 2018 and 2025. During these meetings, details regarding the Quarry Lakes Parkway Project were presented and open for discussion.  Thirty-four formal actions have been taken by the City Council between 2021 and March 2026 related to the project.

Project changes (complete streets improvements) were specifically discussed at BPAC meetings (2018–2025) and the offsite mitigation was discussed at the City Council (2025– 2026) and BPAC (2024–2025) meetings related to RM3 Funding.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-1 April 2026

4. Evaluation of Environmental Impacts
As described in Section 2, the purpose of this CEQA addendum is to review the relevant environmental topic areas for any project changes in circumstances or substantial new information as defined under the State CEQA Guidelines (Section 15162). The impact tables and corresponding discussions within this section describe project impacts compared to the environmental impacts of the approved project identified in the EWC 2009 EIR. In the tables, the impacts are described as less than significant (LTS), less than significant with mitigation (LTSM), significant and unavoidable (SU), or not applicable (N/A), with mitigation measures included as applicable.

4.1 Aesthetics
Table 4-1. Aesthetics Environmental Checklist
Impact
Approved Project
Impact Revised Project Impact Change in Impact
Aesthetics
AES-1: The proposed project would not
have a substantial adverse effect on a
scenic vista or substantially damage scenic
resources.

LTS LTS No
AES-2: The proposed project would not
substantially degrade the existing visual
character or quality of the site and its
surroundings.

LTS LTS No
AES-3: The proposed project could create
a new source of substantial light or glare,
but it would not adversely affect day or
nighttime views in the area.

LTS LTS No
AES-4: Temporary Degradation of Visual
Character or Visual Quality along New
Roadway Segment between Paseo Padre
Parkway and Alvarado-Niles Road during
Construction.

LTSM
AES-1
LTSM
AES-1
No
AES-5: Change of Visual Character or
Visual Quality along New Roadway
Segment between Paseo Padre Parkway
and Alvarado-Niles Road.

LTSM
AES-2, AES-3
LTSM
AES-2
(AES-3 not applicable
to QLP Phases 1–4)
No
AES-6: Potential Placement of Soundwalls
Adjacent to Residential Property between
Paseo Padre Parkway and Alvarado-Niles
Road.

LTSM
AES-3
LTSM overall; LTS for
QLP Phases 1–4
(AES-3 not applicable
to QLP Phases 1–4)
No

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-2 April 2026
Impact
Approved Project
Impact Revised Project Impact Change in Impact
AES-7: Encroachment of Quarry Lakes
Drive Realignment Option 2 (Four-Way
Intersection) into Arroyo Park.

LTSM
AES-4
Less impact (LTS)
Revised design would
not include roadway
through Arroyo Park,
only trail, so AES-4 no
longer needed.

Yes: Less
AES-8: Obstruction of Scenic Vistas from
Public Trails Adjacent to Old Alameda
Creek.

LTSM
AES-2, AES-3, AE-5
LTSM
AES-2
(AES-3 and AES-5 do
not apply to QLP
Phases 1–4)
No
AES-9: New Source of Light and Glare from
New Roadway between Paseo Padre
Parkway and Alvarado-Niles Road.

LTSM
AES-6
LTSM
AES-6
No
AES-10: Degradation of Visual Character or
Visual Quality along the Redevelopment
Corridor between Alvarado-Niles Road and
Mission Boulevard (SR 238).

LTS LTS No
AES-11: New Source of Light and Glare
along BART Corridor during Construction.

LTSM
AES-7, NOI-2
LTSM
AES-7, NOI-2
No
AES-12: New Source of Light and Glare
from New Roadway between AlvaradoNiles Road and Mission Boulevard (SR 238).

LTSM
AES-6
LTSM
AES-7, NOI-2
No
Changes in Aesthetics Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes and Drainage Infrastructure Changes: The roadway and drainage infrastructure changes would not result in new significant or substantially more severe significant aesthetic impacts compared to those described in the EWC 2009 EIR.

The realignment of QLD would shift visual impacts slightly north but would not change the nature of the impacts or introduce new or more severe significant impacts. Removal of the QLD/Osprey Drive connection would reduce long-term visual impacts on residents of Osprey Drive, Towhee Court, and Kinglet Court compared to the approved project.

Consistent with the approved project, the refined project would still include a trail connection from Osprey Drive through Arroyo Park to QLD. Visual impacts from the refined project would be reduced at this location compared to the approved project due to the exclusion of the previously proposed direct roadway connection that would have encroached on parkland and resulted in a significant visual change from recreational uses to roadway infrastructure. As a result, Mitigation Measure AES-4 related to Arroyo Park would no longer be required. The slight reconfiguration of the Lotus Pond Common/Alvarado-Niles Road intersection would not change aesthetics at the intersection. Removal of the existing

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-3 April 2026
access road over the Line M Flood Control Channel would improve aesthetics at this location.

Construction of the new 2-foot concrete weir at the Old Alameda Creek outfall to the Alameda Creek Flood Control Channel would not result in a significant visual change, as this feature is small in stature and would be confined within the existing concrete pad. The new water quality basin would be in the same location as the previously proposed mitigation area and would not substantially alter views compared to those analyzed in the EWC 2009 EIR. The relocated Line M Flood Control Channel would encroach into the Corp Yard parking lot, but the Corp Yard consists of urban development and the changes to the Corp Yard would only consist of a realigned perimeter wall and realigned bus parking areas. The Line M Overflow Pipeline would be buried, and the change in diameter from 84 to 60 inches would have no effect on aesthetics.

Offsite Mitigation: The project would establish and enhance wetland and riparian habitats and preserve existing habitats within an offsite mitigation property in the hills north of Livermore. The proposed mitigation area consists of five easement areas near the Manning Road/Highland Road intersection. The existing properties consist of undeveloped open space with sparse development in the vicinity, including a small satellite station to the northwest and two small ranch homes and associated barn, corral, and fencing.

Implementation of the mitigation plan would include creating and enhancing seasonal wetland and riparian habitat including, but not limited to, creating wetland ponds and riparian enhancement near Cayetano Creek. Drainage features would also be established by excavating and grading sinuous, linear channels in formerly upland areas. These drainage features would then feed into seasonal wetlands that would be constructed on site.

Temporary visual impacts with the potential to degrade the visual quality of the site would include visible flagging, earthmoving activities, and the presence of construction and hauling equipment. However, these impacts would be temporary and would cease following completion of construction activities. No new sources of lighting or glare would be introduced on site. Once construction is complete, the mitigation area would visually resemble the existing open space and riparian habitat near Cayetano Creek, enhancing existing habitat and resulting in a beneficial visual effect.

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant aesthetic impacts with adherence to the mitigation measures identified in the EWC 2009 EIR. The project would implement mitigation measures identified in the EWC 2009 EIR to minimize visual impacts associated with construction and operation of the project between Old Alameda Creek and Alvarado-Niles Road (Mitigation Measures AES-1, AES-2, AES-6, AES7, and NOI-2). Mitigation Measure AES-3 is not applicable to QLP Phases 1–4, as soundwalls are required along Phase 5, and not between Old Alameda Creek and Alvarado-Niles Road.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-4 April 2026
As noted, Mitigation Measure AES-4 is no longer required and would not be implemented.

Mitigation Measure AES-5 is applicable to Phase 5 and not QLP Phases 1–4. The redesigned project would not result in new significant effects or substantially more severe significant aesthetic impacts compared to those disclosed in the EWC 2009 EIR, and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-5 April 2026

4.2 Air Quality
Table 4-2. Air Quality Environmental Checklist
Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Air Quality
AQ-1: Temporary Increase in Ozone
Precursors (ROG and NOX), CO, and PM10
Emissions during Grading and
Construction Activities
SU
AIR-1
SU
AIR-1
No
AQ-2: Violation of CO NAAQS or CAAQS LTS/beneficial LTS/beneficial No AQ-3: Increase in Greenhouse Gas
Contaminant Emissions
LTSM
AIR-2
LTSM
AIR-2
No
AQ-4: Increase in Localized MSAT
Emissions
LTS LTS No
CAAQS = California Ambient Air Quality Standards; CO = carbon monoxide; MSAT = mobile-source air toxic; NAAQS = National Ambient Air Quality Standards; NOX = nitrogen oxides; PM10 = particulate matter 10 microns or less in diameter; ROG = reactive organic gases
Changes in Air Quality Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes and Drainage Infrastructure Changes: The roadway and drainage project changes would not result in new significant impacts or substantially more severe significant air quality impacts because the refined project would still occur within the San Francisco Bay Area Air Basin and roadway traffic volumes and the area of disturbance and construction activity would be similar to (or less than) that described in the EWC 2009 EIR.

Construction effort for roadway elements would not change relative to the realigned QLD, would be reduced with elimination of the Osprey Drive/QLD roadway connection, and would slightly increase relative to the Lotus Pond Common/Alvarado-Niles Road intersection and removal of the access road over the Line M Flood Control Channel.

Construction effort would be slightly increased relative to the 2-foot concrete wall and the Line M relocation into the Corp Yard, and slightly reduced relative to the Line M Overflow Pipeline. There would be a substantial reduction in construction activity with the change from the onsite wetlands/water/riparian mitigation to the new water quality basin due to the substantial reduction in excavation. Consequently, overall construction effort for roadway and drainage infrastructure would be similar to (or less than) that described in the EWC 2009 EIR.

Operationally, the only roadway or drainage infrastructure change that would affect operational air quality is the elimination of the Osprey Drive/QLD roadway connection and the retention of the Osprey Drive connection to Alvarado-Niles Road. This would reduce traffic-related emissions along Osprey Drive due to elimination of through traffic between Alvarado-Niles Road and QLD. Compared to no-project conditions, the QLP Phases 1–4

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-6 April 2026
project would reduce traffic levels along Osprey Drive, because it would eliminate through traffic currently using Osprey Drive between Alvarado-Niles Road and QLD, and traffic along Osprey Drive under the QLP Phases 1–4 project would only consist of local neighborhood traffic. Consequently, roadway emissions along Osprey Drive would be less with the project than under no-project conditions.

Offsite Mitigation: The QLP Phases 1–4 project would establish and enhance wetlands and riparian habitat at an offsite mitigation property north of Livermore. As presented in Table 3-2, the redesigned project would require substantially less excavation and fill volumes compared to the wetlands/waters/riparian mitigation in the approved project, thereby reducing construction-period project emissions within the San Francisco Bay Area Air Basin.

Construction adjacent to the two residences near the mitigation area would be limited in scale and extent and would be temporary, and operational emissions would be limited to periodic maintenance activities and would not represent a substantial new source of operational emissions.

Conclusion: The QLP Phases 1–4 project would implement Mitigation Measures AIR-1 and AIR-2, as identified in the EWC 2009 EIR. Implementation of Mitigation Measures AIR-1 and AIR-2 would reduce criteria air pollutants and greenhouse gas (GHG) emissions during construction by employing best management practices (BMPs). The project overall, combining the roadway project elements in Union City and the offsite mitigation area activities north of Livermore, would result in the same level of air quality impacts as disclosed in the EWC 2009 EIR, as shown in Table 4-2. The redesigned project would not result in any new significant effects or substantially more severe significant air quality impacts compared to those disclosed in the EWC 2009 EIR, and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-7 April 2026

4.3 Biological Resources
Note: Changes to impact titles or mitigation measures are noted in strikeout and underline in this section.

Table 4-3. Biological Resources Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact
Change in
Impact
Biological Resources
BIO-1: Degradation of Water Quality in
Crandall Creek from Construction
Activities Associated with the Roadway
Widening.

LTSM
HWQ-1
N/A. QLP Phases 1–4 do
not cross Crandall Creek.

N/A
BIO-2: Loss of or Disturbance to SpecialStatus Plants.LTS LTS No BIO-3: Loss of or Disturbance to Western
Burrowing Owls or their Nesting and
Foraging Habitat.

LTS LTSM
BIO-2 (revised)
No
BIO-4: Loss of or Disturbance to Other
Special Status Wildlife Species California
Red-Legged Frogs, California Tiger
Salamanders, Western Pond Turtles, and
their Habitat.

LTSM
BIO-1, BIO-2,
HWQ-1
LTSM
BIO-1 (revised), BIO-2
(revised), HWQ-1
No
BIO-5: Potential Loss of Nesting
Migratory Birds, including Raptors, Bird
Species of Special Concern or Loss of
their Nests or Eggs.

LTSM
BIO-3
LTSM
BIO-3 (revised)
No
BIO-6: Disturbance to Anadromous
Steelhead and their Habitat from
Construction Activities at Alameda Creek
Flood Control Channel.

LTSM
BIO-4, BIO-5, BIO6, HWQ-3
N/A. QLP Phases 1–4 do
not cross the Alameda
Creek Flood Control
Channel.

N/A
BIO-7: Loss of Disturbed or Non-Sensitive
Habitats.

LTS LTS No
BIO-8: Degradation of Water Quality in
Aquatic Resources from Construction
Activities.

LTSM
HWQ-3
LTSM
HWQ-3
No
BIO-9: Permanent Loss and Temporary
Disturbance of a Sensitive Community—
Willow Riparian Woodland and Scrub.

LTSM
BIO-7, BIO-8
LTSM
BIO-7 (revised), BIO-8
No
BIO-10: Potential Introduction or Spread
of Noxious Weeds into a Sensitive Plant
Community.

LTSM
BIO-9
LTSM
BIO-9
No
BIO-11: Loss of Wetlands and Other
Waters of the United States and of the
State.

LTSM
BIO-7, BIO-10
LTSM
BIO-7 (revised), BIO-10
No

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-8 April 2026
Impact
Approved Project
Impact
Revised Project
Impact
Change in
Impact
BIO-12: Change in Steelhead Migratory
Habitat Resulting from Installation of
New Bridge at Alameda Creek Flood
Control Channel.

LTS N/A. QLP Phases 1–4 do
not cross the Alameda
Creek Flood Control
Channel.

N/A
BIO-13: Loss of or Disturbance to
Protected Trees.

LTSM
BIO-11, BIO-12
LTS
BIO-11, BIO-12
No
This section first summarizes changes in biological resource effects associated with individual project changes and then analyzes changes under each impact title (e.g., BIO-1, BIO-2, and so on).

Summary of Impacts Associated with Individual Project Changes Table 4-4 below presents changes in the area of impacts on biological resources and mitigation.

Roadway Project Changes: The roadway project changes would not result in new significant impacts or substantially more severe significant biological resource impacts because the area of disturbance to onsite upland and aquatic habitat would be similar to that described in the EWC 2009 EIR. The realignment of QLD would not disturb a larger area than the original alignment and would not encounter different biological resources. Removal of the connection of QLD to Osprey Drive was included in one of the options in the EWC 2009 EIR, and the improvements along Osprey Drive only encroach into areas that have been previously disturbed by farming activities. The improvements along Lotus Pond Common would disturb a small area (0.1 acre) of nonnative annual grassland that is far enough away from Old Alameda Creek that it does not provide upland habitat for California red-legged frogs (CRLF), California tiger salamander (CTS), or western pond turtle. It may provide habitat for Crotch’s bumble bee (CBB) . Removal of the access road over the Line M Flood Control Channel would cause temporary disturbance in a small area of the Line M Flood Control Channel but would also result in an increased amount of creek habitat that would be permanently daylighted.

Drainage Infrastructure Changes: The drainage infrastructure changes would not result in new significant or substantially more severe significant biological resource impacts because the area of disturbance on site within areas of upland and aquatic habitat would be similar to that described in the EWC 2009 EIR. Placement of the 2-foot concrete weir wall on an existing concrete pad for the outfall from Old Alameda Creek to the Alameda Creek Flood Control Channel would not result in permanent conversion of any habitat; there would be temporary disturbance of a small amount of riparian habitat during construction.

Temporary areas would be restored and compensatory mitigation would be provided at the offsite mitigation area.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-9 April 2026
Table 4-4. Changes in Impacts on Sensitive Biological Resources with Quarry Lakes Parkway, Phases 1 to 4 compared to the 2009 EIR1 Habitat
Impacts (ac or lf) Mitigation Ratios Mitigation (ac or lf) 2009 EIR QLP 1–4 Change 2009 EIR QLP 1–4 2009 EIR2 QLP 1–43 Change Wetlands (ac) 0.94 (P) 1.09 (P)

0.14 (T)
+0.15 (P)4
+0.14(T)
2:1 (P) 3:1 (P) 1.88 ~3.40 +1.72
Waters (ac, lf) 0.23 (P, ac)
1,132 (lf)

0.43 (P, ac)
1,421 (P, lf)

0.03 (T, ac)
+0.20 (P, ac)5
+289 (P, lf)
+0.03 (T, ac)
1:1(P) 1:1 (P, onsite)
2:1 (P, offsite)

0.23 ac
1,132 lf
~0.65 ac
~2,512 lf
+0.42 ac
+1,380 lf
Riparian Vegetation (acres) 3.20 (T)6 0.28 (P)

0.11 (T)
+0.28 P6
-3.09 T
2:1 (P)
1:1(T)
2:1 (P)

1.3:1 (T)

3.20 ~1.00 -2.20
Upland Habitat for CRLF and CTS (ac) N/A7 up to 5.96 (P, roadway) up to 0.51 (T, roadway

3.80 (P, HMMP) converted to
wetlands/waters

0.34 (T, HMMP)
See QLP 1–4 impacts None7 3:1 (P, roadway)
1:1 (T, roadway)
No mitigation needed for
HMMP7
None (7) ~18.0 +18.0
Habitat for Burrowing Owl (ac) N/A8 Offsite mitigation area

3.80 (P, HMMP) converted to
wetlands/waters

0.34 (T, HMMP)
See QLP 1–4 impacts None N/A None ~18.01 +18.0
Habitat for CBB(ac) N/A9 6.07 (P)

0.65 (T)
N/A None8 If present, 1:1 None (8) up to 18.0
(if needed)
+18.0
Habitat for WBB(ac) N/A9 3.80 (P)

0.34 (T)
N/A None8 If present, 1:1 None (8) up to 18.0
(if needed)
+18.0
1 This table focuses only on the segment from Old Alameda Creek to Mission Boulevard, as that is the location of changes from the EWC 2009 EIR with QLP Phases 1–4. This table does not include impacts or mitigation for impacts related to QLP Phase 5 or in the Fremont portion of the EWC but does include temporary impacts related to the prior wetland mitigation plan that are included in the EIR, so these acreages are not specifically comparable to Table 3.3.6 in the EWC 2009 EIR. 2 This is the required mitigation per ratios in the EWC 2009 EIR. The EWC 2009 EIR includes additional mitigation for impacts related to EWC elements related to QLP Phase 5 and the Fremont portion that are not part of QLP Phases 1–4. 3 This is the amount of approximate proposed mitigation for QLP Phases 1–4 including onsite (new Line M, ~712 lf,~ 0.6 ac) and offsite (~3.4 ac wetland, ~1,800 lf of channel, ~1.0 ac of riparian) and preservation of ~18 ac of upland for CTS and CRLF. 4 In the EWC 2009 EIR, Basin 2C was mapped as 0.87 ac. In the 2023 delineation, it was mapped as 1.07 ac and several additional isolated wetlands were also identified near New Basin, which is the reason for the change in impacts. This was a change in delineated area, but not a change in project footprint.
5 While an increase in impact on waters is identified, this is a change in the delineated area, but not a change in project footprint. 6 The onsite mitigation plan in the EWC 2009 EIR would have required temporary disturbance to 3.2 ac of riparian areas along Old Alameda Creek. The onsite mitigation plan was mitigating for all impacts associated with EWC, not just the part corresponding to QLP Phases 1–4.

Because the EWC 2009 EIR does not divide the mitigation area into mitigation for different parts of the EWC, all temporary impacts on riparian areas are included in this table. In the future when QLP Phase 5 is advanced, it would require separate and additional mitigation than proposed for QLP Phases 1–4. 7 At the time of the EWC 2009 EIR, there was a question of whether CTS and CRLF were present at the project site and the EWC 2009 EIR did not include habitat mitigation, only preconstruction surveys and avoidance if found. Subsequently, consultants to Union City conducted protocol surveys and found no CTS or CRLF at the project site. However, the resource agencies (USFWS and CDFW) did not accept the negative findings of the surveys and stated that habitat for these species was present at the site; therefore, this addendum now identifies suitable habitat for these species on site (although they have not been found on site). This is not a change in actual physical impact, but a change in definition per the direction from USFWS and CDFW. See text discussion of changes in nonnative annual grassland. Mitigation is not proposed for HMMP permanent conversion of nonnative grassland to wetlands/water/riparian, as new areas would be habitat for CTS and CRLF or for temporary HMMP disturbance of nonnative annual grassland due to the short-term nature of disturbance and restoration. 8 The EWC 2009 identified that there was a very low potential for burrowing owl on the roadway project site, so it did not identify habitat impacts. The offsite mitigation area does contain suitable burrowing owl habitat so the area of impact for the HMMP is shown here. The preservation of annual grassland for CTS and CRLF will also address conversion of burrowing owl habitat to seasonal wetland, channel, and riparian habitat. 9 The EWC 2009 EIR did not analyze habitat or potential impacts on CBB or WBB, as they were not identified by any resource agency as a sensitive species at the time. ~ = approximately; ac = acres; lf = linear feet; P = permanent; T = temporary; WBB = western bumble bee

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-10 April 2026
The new water quality basin would be within the area of the previously proposed onsite mitigation area and would therefore not disturb new areas of habitat. The water quality basin would require far less excavation than the originally proposed onsite mitigation; this level of excavation would not disturb riparian or wetland areas as the originally proposed onsite mitigation would have. Discharge from the new water quality basin to Old Alameda Creek will not adversely affect habitat in the creek because of treatment prior to discharge. The relocation of Line M Flood Control Channel into the southern part of the Corp Yard would not affect habitat because the Corp Yard has been previously developed. The reduction in size of the Line M Overflow Pipeline would not result in any new disturbance to habitat.

Offsite Mitigation: As discussed in Section 3.3, the proposed offsite mitigation property contains existing aquatic features that would be enhanced as part of the HMMP in addition to existing annual grassland habitat where new aquatic features would be constructed. The offsite mitigation area would require disturbance of approximately 4.17 acres of nonnative annual grassland (permanent disturbance of approximately 3.80 acres and temporary disturbance of approximately 0.37 acre) in the locations of construction of new wetlands (approximately

3.40 acres), channel (approximately 0.3 acre), riparian planting (approximately 0.003 acre), a rock spillway (approximately 0.001 acre), a willow revetment (~0.02 acre), and for soil fill/spoil areas (approximately 0.34 acre) and disturbance of a small area of existing wetlands/waters (approximately 0.028 acre). Temporarily disturbed nonnative annual grassland (approximately

0.34 acre) and wetlands/waters (approximately 0.028 acre) would be restored after construction. The other areas of nonnative annual grassland would be converted to new wetlands, channels, riparian areas, and a small area for a spillway. This would result in a permanent conversion of approximately 3.80 acres of nonnative annual grassland to wetland, channel, and riparian habitats. The nonnative annual grassland at the offsite mitigation area is habitat for CTS, CRLF, burrowing owl, and other species. Three potential soil fill/spoil areas (see Figure 3-18) have been identified: (1) primary site – PG&E site (approximately 7.5 acres, graded, compacted, no vegetation); (2) primary site at Eagle Ridge Preserve (approximately 0.34 acre, nonnative grassland); and (3) secondary site at Carneal Ranch (approximately 0.28 acre, previously disturbed mining/excavation area with a mix of unvegetated gravel with nonnative ruderal vegetation), if necessary. If soil fill/spoil areas contain nonnative annual grassland, temporary disturbance would be restored and seeded, so no additional conversion of nonnative annual grassland would occur due to fill/placement. Separately, approximately 18 acres of nonnative annual grassland would be preserved and managed for the benefit of CTS and CRLF.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-11 April 2026
Description of Impacts by EIR Impact Title
BIO-1: Degradation of Water Quality in Crandall Creek from Construction Activities Associated with the Roadway Widening
The changes in the QLP Phases 1–4 project would not affect Crandall Creek, which is crossed by the East West Connector along Decoto Road, far from the QLP Phases 1–4 project.

BIO-2: Loss of or Disturbance to Special-Status Plants
As explained in the EWC 2009 EIR, the study area for the roadway project contained habitat for two special-status plant species. These are Congdon’s tarplant (Centramadia parryi ssp. congdonii), a CNPS List 1B species that could occur in nonnative annual grasslands, and slender-leaved pondweed (Potamogeton filiformis), a CNPS List 2 species that could occur in areas of standing water. However, floristic surveys of the roadway project area did not identify either of these plants to be occurring onsite. Consequently, the changes in the roadway project will not change the impacts on special-status plant species as none are known to occur onsite.

The offsite mitigation area also contains habitat for Congdon’s tarplant and occurs on the fringe area of wetlands on the mitigation property. The proposed mitigation includes grading of upland areas and conversion to seasonal wetlands and will result in increasing the area occupied by this plant on the mitigation site. The mitigation developer has conducted salvage of Congdon’s tarplant seed from other locations and have set aside this seed to utilize in restoration efforts. In addition, the proposed 18 acres of annual grassland habitat to be preserved may also have Congdon’s tarplant. With the planned mitigation, the area of habitat for Congdon’s tarplant, any disturbance to individual plants will be compensated for onsite, and the impact on this species will be less than significant. This is the same conclusion reported for this species in the EWC 2009 EIR.

BIO-3: Loss of or Disturbance to Western Burrowing Owls or their Nesting and Foraging Habitat
The EWC 2009 EIR analyzed potential impacts of the roadway project on burrowing owl, describing that despite low to marginal grassland habitat present in the agricultural fields and annual grasslands onsite, the likelihood for this species to be found onsite is low. This is due to the very limited number of mammal burrows in the roadway project area and because no sign of the species was observed during any of the wildlife surveys conducted for the EIR. While any patch of annual grassland in an urban area in the Bay Area region could be considered potential habitat for western burrowing owl, no owls have been observed along the roadway alignment during the nesting or wintering period. Further, there are no nesting owls or owl colonies in the project vicinity that could be foraging in the annual grasslands along the project alignment, including the area along Old Alameda Creek.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-12 April 2026
Impacts on nesting, wintering, or foraging western burrowing owls was identified as less than significant in the EWC 2009 EIR and no mitigation was required. That conclusion remains unchanged for the roadway project.

The offsite mitigation area, however, does provide suitable burrowing owl habitat including foraging habitat in annual grassland areas and breeding habitat in squirrel burrows, and there are occurrences of burrowing owl in adjacent areas. The mitigation construction in annual grassland areas could disturb burrowing owls including nesting owls during breeding season. Mitigation Measure BIO-2 has been revised to include surveying and avoidance of nesting owls during mitigation ground disturbance in annual grassland habitat, which includes implementation of construction buffers around active nest sites in accordance with CDFW guidance. The proposed mitigation would convert approximately 3.8 acres of annual grassland habitat to seasonal wetland, channel, and riparian habitat and temporarily disturb an additional 0.37 acre of annual grassland habitat. The temporarily disturbed area will be restored to annual grassland habitat. The proposed offsite mitigation also includes preservation of 18 acres of annual grassland habitat that will offset the permanent conversation of annual grassland habitat. With the revised mitigation, the impact would be less than significant, which is the same conclusion for this species in the EWC 2009 EIR.

BIO-4: Loss of or Disturbance to Other Special Status Wildlife Species California Red-Legged Frogs, California Tiger Salamanders, Western Pond Turtles and their Habitat
Species Analyzed in the EWC 2009 EIR:

California Red-Legged Frog and California Tiger Salamander. The EWC 2009 EIR analyzed potential impacts on CRLF and CTS, describing that surveys of the site did not indicate any presence of the species, that the potential for them to occur was extremely low, and that the project was not expected to adversely affect these species. Mitigation Measure BIO-2 included preconstruction surveys for these species and relocation of the species if found, if necessary. Subsequent to the EWC 2009 EIR, consultants to ACTC conducted protocol surveys for CRLF and CTS at the project site, did not find the species to be present, and provided results of the surveys to USFWS. Despite the negative finding from the protocol surveys, USFWS identified that CTS and CRLF still had the potential to migrate to the project site due to potential connection through the Line M drainage from uphill areas and/or through the Quarry Lakes or the Alameda Creek Flood Control Channel, even though there are substantial barriers to movement like Mission Boulevard (SR 238) and other roadways and despite the presence of fish in the Quarry Lakes and the Alameda Creek Flood Control Channel. Despite not agreeing with the USFWS perspective, the City of Union City decided to treat the site as containing potential habitat for the species and providing compensatory habitat mitigation for project effects for that potential impact. Mitigation Measure BIO-2 was revised as shown below to include compensatory habitat mitigation, which would be

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-13 April 2026
provided at the offsite mitigation area. With the revised mitigation, the impact would be less than significant, which is the same conclusion in the EWC 2009 EIR.

Western pond turtle (Actinemys marmorata) is a CDFW species of special concern. The subspecies of western pond turtle that occurs in the vicinity of the roadway action area is northwestern pond turtle. Northwestern pond turtle was proposed for threatened status under the federal Endangered Species Act in October 2023. The EWC 2009 EIR addressed western pond turtle as a species of special concern, identified impacts, and included mitigation to address those effects. Therefore, the listing by USFWS in 2023 does not represent a change in environmental conditions because the species was already treated as a species of special concern in the EWC 2009 EIR.

New Candidate Species Not Analyzed in the EWC 2009 EIR:

Two species were designated as candidate species since completion of the EWC 2009 EIR.

Crotch’s bumble bee (Bombus crotchii) is a candidate for listing under the California Endangered Species Act. While CDFW considers listing a candidate species, it receives protection as if it were listed. The species has a limited distribution in southwestern North America. This species occurs primarily in California, including the Mediterranean region, Pacific Coast, West Desert, Great Valley, and adjacent foothills through most of southwestern California. It also occurs in Mexico (Baja California and Baja California Sur) and has been documented in southwestern Nevada, near the California border. In California, CBB inhabits open grasslands and scrub habitats. This species was historically common in the Central Valley of California but now appears to be absent from most of it, especially in the center of its historical range. There are no occurrences of this species within 5 miles of the roadway project area (CDFW 2025). The closest California Natural Diversity Database occurrence is 5.21 miles away. The grasslands and flowering plants within the roadway project area provide suitable habitat for the species. While it was not observed at the offsite mitigation area, the open grassland habitat and flowering plants at the offsite mitigation site are likely considered habitat for CBB.

Construction of the roadway and associated project elements would result in the permanent removal of 2.27 acres of potential CBB habitat and temporary impacts on 0.31 acre of potential CBB habitat (Figure 4-1). Direct effects on CBB individuals and nests may result from vehicle/equipment strikes and materials placement (crushing); nest collapse associated with earthwork, vegetation removal, or vehicle passage (entombment, crushing, or suffocation); and equipment laydown, trenching, other excavations, grading, or placement of spoils and/or fill materials (entombment, crushing, or suffocation).

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CEQA Addendum No. 1 4-14 April 2026
Figure 4-1. Crotch’s Bumble Bee Habitat Impact Map in the Roadway Project Area

4. Evaluation of Environmental Impacts
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CEQA Addendum No. 1 4-15 April 2026
Indirect effects on CBB may include temporary habitat losses, increased habitat fragmentation and edge effects, effects from lighting at night, and the project’s incremental contribution to cumulative impacts. Other potential indirect impacts include stress resulting from noise and vibration from ground disturbance, equipment operation, and traffic; increased exposure or stress from disorientation; introduction or spread of invasive species; and long-term effects.

Long-term effects could include displacement from preferred habitat; barriers to movement to and increased travel distance to breeding habitat (decreased reproductive output, energetic expenses, and exposure to predation and elements); loss of foraging habitat; changes in drainage patterns that favor different vegetative growth; increased pollution; increased competition for food and space; loss of nesting habitat used for shelter, reproduction, and escape cover; increased vulnerability to predation; and exposure to contaminants through introduction of contaminated water or contaminated substrates.

Individuals displaced due to habitat loss and degradation may be unable to survive in adjacent areas if these areas are at carrying capacity or are unsuitable for colonization.

Construction of offsite mitigation would temporarily disturb approximately 0.34 acre of upland grassland habitat, which would be restored following construction, and permanently convert 3.80 acres of upland grassland habitat to wetlands, waters, and riparian habitat.

Total permanent roadway and offsite mitigation loss of upland grassland habitat would be approximately 6.07 acres. However, the project would preserve approximately 18 acres of upland grasslands habitat at the offsite mitigation area.

Mitigation Measures BIO-1 and BIO-2 from the EWC 2009 EIR have been modified to include construction worker awareness training, preconstruction surveys, avoidance and minimization measures for CBB, and compensatory mitigation if CBB is found on the project site in preconstruction surveys.

Western bumble bee (Bombus occidentalis, WBB) is a candidate for listing under the California Endangered Species Act. Suitable habitat includes meadows and grasslands that support diverse and abundant floral resources. Although WBB was historically widespread throughout the mountains and northern coast of California, it is now largely confined to high-elevation sites with a small handful of records on the Northern California coast. The roadway project area is outside the species’ known range (CDFW 2025). While WBB has not been observed in the offsite mitigation area, there are nearby California Natural Diversity Database occurrences, and several of the required food plants for this species are known to occur throughout the annual grassland habitat. Therefore, this species is considered to have the potential to occur at the offsite mitigation area.

Construction of the offsite mitigation area would temporarily disturb approximately

0.34 acre of upland grassland habitat, which would be restored following construction, and

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-16 April 2026
permanently convert 3.80 acres of upland grassland habitat to wetlands, waters, and riparian habitat. The project would also preserve approximately 18 acres of upland grasslands habitat at the offsite mitigation area.

BIO-5: Potential Loss of Nesting Migratory Birds, including Bird Species of Special Concern or Loss of their Nests or Eggs
The EWC 2009 EIR described that project construction activities would require the use of heavy equipment, which could cause disturbance to birds and raptors nesting and foraging in the area. General human presence, activity, and noise during project construction may also disturb nesting and foraging. All natural and landscaped areas provide suitable nesting habitat for migratory birds. If occupied nests are present on or adjacent to the construction area, construction activities could result in the abandonment of nests, the death of nestlings, or the destruction of eggs in active nests. Because the death of nestlings or destruction of eggs would violate these acts, this impact is considered significant. The EWC EIR identified Mitigation Measure BIO-3, which would require preconstruction surveys and protective measures for nesting birds, if necessary.

The offsite mitigation area provides potential nesting habitat for grasshopper sparrow (Ammodramus savannarum), California horned lark (Eremophila alpestris actia), northern harrier (Circus hudsonius), white-tailed kite (Elanus leucurus), loggerhead shrike (Lanius ludovicianus), and Golden Eagle (Aquila chrysaetos), and there is a potential for disturbance to nests during mitigation development.

The project changes included in the QLP Phases 1–4 project, including the proposed offsite mitigation would have similar effects as disclosed in the EWC 2009 EIR as nesting birds may be present at the roadway project area and at the offsite mitigation area. As discussed under Impact BIO-7, the changes would result in an increase of impact to 1.1 acres of annual grassland habitat. As shown in Table 4-4, the project changes would result in small increases in permanent and temporary disturbance to wetlands and waters, a small increase in permanent disturbance to riparian areas and a substantial reduction (> 3 acres) in temporary disturbance to riparian areas compared to that in the EWC 2009 EIR. Thus, there may be a slight increase in potential to disturb ground-nesting birds in annual grassland during construction but a reduction in potential to disturb nesting birds in riparian areas.

Mitigation Measure BIO-3 would apply to QLP Phases 1–4 project, including the offsite mitigation and has been modified to include bird species of special concern that have the potential to nest at the offsite mitigation area. With implementation of Mitigation Measure BIO-3, potential impacts on migratory birds, raptors, and bird species of special concern would be reduced to a less-than-significant level by avoiding disturbance to nesting birds, which is the same conclusion as in the EWC 2009 EIR.

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CEQA Addendum No. 1 4-17 April 2026
BIO-6: Disturbance to Anadromous Steelhead and their Habitat from Construction Activities at Alameda Creek Flood Control Channel
The QLP Phases 1–4 project would not include any construction in the Alameda Creek Flood Control Channel and thus will not affect steelhead or their habitat. Thus, this impact does not apply to the QLP Phases 1–4 project.

BIO-7: Loss of Disturbed or Non-Sensitive Habitats
In the EWC 2009 EIR, an onsite mitigation area was proposed in an area of 6.6 acres of existing nonnative grassland that would be converted to wetland, water, and riparian habitat. With the project changes, the following changes would occur:
 Elimination of onsite wetland, water, and riparian mitigation near Old Alameda Creek (reduction of impact to 6.6 acres of non-native annual grassland),  Water quality basin (new impact on 3.8 acres of upland, primarily nonnative annual grassland),
 Lotus Pond Common improvements (new impact on 0.1 acre of nonnative annual grassland), and
 offsite mitigation (new impact on 3.8 acres of nonnative annual grassland converted to other habitats).

The net change would be a 1.1-acre net increase (new impacts of 7.7 acres minus 6.6 acres of avoided impact) in loss of upland habitat, primarily nonnative annual grassland due to the project changes.

As discussed in the EWC 2009 EIR, nonnative annual grasslands, and other non-sensitive habitat are relatively common throughout the region and loss of such areas on their own (separate from their value to special status species as discussed under Impacts BIO-2 through BIO-5) would not have a significant impact. This conclusion is unchanged from the EWC 2009 EIR.

BIO-8: Degradation of Water Quality in Aquatic Resources from Construction Activities
As shown in Table 4-4, there would be a small permanent and temporary increase in impact on wetlands and waters, a small increase in permanent impact on riparian, and a larger reduction in temporary impact on riparian areas such that the overall disturbance to aquatic resources from construction would be less than disclosed in the EWC 2009 EIR.

Nevertheless, construction within aquatic resources could increase erosion, releasing sediment that could affect water quality and downstream habitat. Mitigation Measure HWQ-3 from the EWC 2009 EIR would require water quality protection measures to control

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CEQA Addendum No. 1 4-18 April 2026
and reduce sedimentation and would reduce impacts to a less-than-significant level for the QLP Phases 1–4 project. This is the same conclusion as in the EWC 2009 EIR.

BIO-9: Permanent Loss and Temporary Disturbance of a Sensitive Community— Willow Riparian Woodland and Scrub
The only sensitive community in the project area is willow riparian woodland and scrub.

Within the QLP Phases 1–4 project area, this community is found along the north side of Old Alameda Creek between Quarry Lakes Drive and Arroyo Park (this community is also found in certain areas on the south and east side of Old Alameda Creek outside the QLP Phases 1– 4 project area), as shown in Figure 3-3. In the EWC EIR, this community was going to be disturbed by the roadway improvements and the planned onsite water, wetland, and riparian mitigation in areas north and south of Old Alameda Creek.

The QLP Phases 1–4 project would have a similar effect on this community on the north side of Old Alameda Creek due to roadway construction and construction of the new water quality basin but would not affect any of the area of this community on the south side of Old Alameda Creek. Overall, the project would have less construction disturbance compared to that in the EWC 2009 EIR.

The EWC 2009 EIR mitigated for effects on willow riparian woodland and scrub through the onsite water, wetland, and riparian mitigation along Old Alameda Creek proposed through Mitigation Measure BIO-7. Instead of the mitigation along Old Alameda Creek, the QLP Phases 1–4 project will create and enhance wetlands, waters, and riparian habitat at the offsite mitigation property and Mitigation Measure BIO-7 has been revised accordingly. As shown in Table 4-4, the newly proposed mitigation will compensate for losses of riparian habitat including willow riparian woodland and scrub. Mitigation Measure BIO-8 will apply to protect willow riparian woodland and scrub during construction. With implementation of the Mitigation Measures BIO-7 (as revised) and BIO-8, the impact on this sensitive community will be less than significant. This is the same conclusion as in the EWC 2009 EIR.

BIO-10: Potential Introduction or Spread of Noxious Weeds into a Sensitive Plant Community
As discussed in the EWC 2009 EIR, construction could introduce or spread noxious weed into sensitive plant communities, specifically willow scrub woodland and scrub. As discussed under Impact BIO-9, with the project changes in the QLP Phases 1–4 project, construction would disturb less riparian area overall, including willow riparian woodland and scrub.

Consequently, the impact relative to noxious weeds and sensitive plant communities would the same or less than disclosed in the EWC 2009 EIR. Mitigation Measure BIO-9 would still apply relative to construction near riparian areas to avoid or minimize the spread of noxious weeds and would reduce impacts to a less-than-significant level. This is the same conclusion as in the EWC 2009 EIR.

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BIO-11: Loss of Wetlands and Other Waters of the United States and of the State There would be a reduction in temporary disturbance to waters, wetlands, and riparian areas because the prior onsite mitigation area would have temporarily disturbed approximately 3.2 acres of existing riparian areas versus the currently proposed offsite mitigation area, which would only require temporary disturbance to 0.028 acre of waters and wetlands.

The QLP Phases 1–4 project would result in the permanent loss of wetlands (1.09 acres), waters (0.43 acre), and riparian areas (0.28 acre). These would be small increases in permanent impacts on wetlands (+0.15 acre), waters (+0.20 acre) and riparian (+0.28 acre) areas compared to that disclosed in the EWC 2009 EIR. As compensatory mitigation, the project would include creation of wetlands (approximately 3.40 acres at the offsite mitigation area), waters (approximately 0.65 acre and approximately 712 linear feet in the new Line M Flood Control Channel and approximately 1,418 linear feet of channel at the offsite mitigation area), and riparian areas (approximately 1.0 acre at the offsite mitigation area), which would more than replace the permanent losses.3 Mitigation Measure BIO-7 has been revised to reflect the changes in mitigation from entirely onsite to partially onsite and partially offsite. Mitigation Measure BIO-10 would also apply but has not been revised. With implementation of Mitigation Measures BIO-7 and BIO-10, impacts on wetlands, waters, and riparian areas will be less than significant. This is the same conclusion as in the EWC 2009 EIR.

BIO-12: Change in Steelhead Migratory Habitat Resulting from Installation of New Bridge at Alameda Creek Flood Control Channel
The QLP Phases 1–4 project does not include the bridge over the Alameda Creek Flood Control Channel; this impact does not apply.

BIO-13: Loss of or Disturbance to Protected Trees
As discussed in the EWC 2009 EIR, the roadway project would result in impacts on some trees that qualify for protection under the Fremont or Union City Tree ordinance. Mitigation Measure BIO-11 was required to prepare an arborist’s report and a landscaping plan to compensate for loss of protected trees.

The QLP Phases 1–4 roadway project would also affect trees protected by the two city tree ordinances. The approximate amount of trees should be similar to that disclosed in the EWC 2009 EIR but may be less because the project will not include a roadway connection 3 New Basin, which was constructed by the City of Union City in 2005, as the Line M Detention Basin- Pump Station, City Project No. 03-25 has been determined not to be wetland or water of the state by RWQCB.

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CEQA Addendum No. 1 4-20 April 2026
between Osprey Drive and Quarry Lakes Parkway through Arroyo Park, which has tree cover in certain areas. In addition, the project would not include the onsite water, wetland, and riparian mitigation that would temporarily disturb up to 3 acres of riparian areas. Most of the offsite mitigation area does not have tree cover, with cover limited to a few trees along drainages that may be affected. Mitigation Measures BIO-11 and BIO-12 will apply to the trees affected by the roadway project. The design for the offsite mitigation includes extensive planting of approximate one acres of riparian cover, so tree coverage will increase at the offsite mitigation area. With implementation of Mitigation Measures BIO-11 and BIO12, impacts on protected trees will be less than significant. This is the same conclusion as in the EWC 2009 EIR.

Revisions to Mitigation Measures
Revisions to Mitigation Measure BIO-1 are identified relative to burrowing owl, bird species, CBB, and WBB. Revisions to Mitigation Measure BIO-2 are identified relative to burrowing owl, CBB, WBB, and acknowledge the compensatory mitigation for CRLF and CTS at the offsite mitigation area. Revisions to Mitigation Measure BIO-3 are identified relative to bird species of special concern. Revisions to Mitigation Measure BIO-7 are identified regarding the shift from onsite wetland mitigation to offsite. Changes relative to the originally adopted mitigation are shown in strikeout and underline.

Mitigation Measure BIO-1: Provide Construction Worker with Awareness Training for Special-Status Species and Sensitive Habitats in the Construction Area ACTA Union City will ensure that all construction personnel receive worker awareness training provided by a qualified wildlife biologist experienced in training non-specialists to ensure that they can recognize CRLF, CTS, western pond turtle, burrowing owl, CBB, WBB, raptors, migratory birds, bird species of special concern and other aquatic and riparian wildlife, and that they understand where sensitive resource areas are within the construction zone so that they could minimize their impact on all sensitive habitats.

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preconstruction surveys, the biologist will remain on site during initial ground-disturbing activities to monitor individuals and ensure that CRLF, CTS, and western pond turtles are not affected by construction activities. Whenever possible, the biologist will work with construction crews to avoid impacts on individuals. If necessary, individual turtles, CRLF, and CTS will be relocated by a DFG CDFW-approved biologist, in accordance with DFG CDFW specifications.

If construction activities occur from May through July, there is the possibility of affecting active western pond turtle nests. If preconstruction surveys identify active nests, the biologist will establish visual no-disturbance buffer zones around each nest using temporary orange construction fencing. The demarcation will be permeable to allow young turtles to move away from the nest following hatching. The radius of the buffer zone and the duration of exclusion will be determined in consultation with DFG CDFW.

The buffer zones and fencing will remain in place until the young have left the nest, as determined by a qualified biologist.

Compensatory mitigation for permanent and temporary loss of habitat for CRLF and CTS shall be provided at the offsite mitigation area at a ratio of 3:1 for permanent impacts and 1:1 for temporary impacts with approximately 18 acres of upland habitat to be preserved at the site.

Burrowing Owl
Prior to any ground disturbance activity at the offsite mitigation site planned during the fall and winter non-nesting season (September 1 through January 31) or at any time during the construction process, the mitigation contractor(s) will retain a qualified wildlife biologist to conduct non-breeding season surveys for burrowing owls.

Survey methodology will follow the guidance provided by CDFW’s Staff Report on Burrowing Owl Mitigation, Appendix D (California Department of Fish and Game 2012). Surveys will be conducted at each area of suitable habitat that will be disturbed.

The survey area will cover all suitable burrowing owl habitat subject to disturbance pursuant to CDFW’s Staff Report on Burrowing Owl Mitigation (California Department of Fish and Game 2012). If any burrowing owls are found within the disturbance area, the mitigation contractor will notify CDFW and will proceed under CDFW direction.

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will be timed in accordance with CDFW’s Staff Report on Burrowing Owl Mitigation, Appendix D, Breeding and Non-Breeding Season Surveys and Reports (California Department of Fish and Game 2012). This will provide the Project team advance notice of nesting owls and allow ample time to discuss appropriate avoidance measures with CDFW.

In addition, take avoidance surveys will be conducted no less than 14 days prior to ground-disturbing activities and a final survey will be conducted within 24 hours prior to ground disturbance in all areas of the environmental footprint supporting burrowing owl habitat. If the biologist identifies the presence of a burrowing owl nest in an area scheduled to be disturbed by construction, a 660-foot (~200-meter) no-activity buffer will be established and maintained around the nest while it is active. Surveys and buffer establishment will be performed by qualified wildlife biologists, will be coordinated with CDFW, and will be subject to CDFW review and oversight. The buffer distance will be determined by the time of the year and level of disturbance as recommended in CDFW’s Staff Report on Burrowing Owl Mitigation (California Department of Fish and Game 2012) (see table below).

Location Time of Year
Level of Disturbance
Low Medium High
Nesting sites April 1- Aug 15 200 m 500 m 500 m
Nesting sites Aug 16-Oct 15 200 m 200 m 500 m
Nesting sites Oct 16-Mar 31 50 m 100 m 500 m
m = meters
Crotch’s Bumblebee (CBB) and Western Bumblebee (WBB)
Prior to each phase of construction, a qualified biologist shall conduct a take avoidance survey for active CBB (roadway project area and offsite mitigation area) and WBB (offsite mitigation area only) colony nesting sites. To maximize detection of active bee colonies, the take avoidance survey shall be conducted during the spring, summer, or fall during appropriate weather (not during cool, overcast, rainy, or windy days). The biologist shall walk the entire area proposed for grading and inspect all ground squirrel burrows for bumble bee activity. If any bumble bees are identified during the survey, they shall be identified to species to the extent feasible.

All active colonies of CBB and WBB shall be avoided and no work shall occur within a minimum of 50 feet of the colony. If the colony is in a location proposed for development, consultation with CDFW will be initiated and an Incidental Take Permit from CDFW will be required prior to disturbance. Where feasible, buffers may be adjusted in consultation with CDFW based on site conditions, colony status, and

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implementation of additional minimization measures (e.g., phased vegetation removal, activity windows).

If take or adverse impacts on CBB or WBB cannot be avoided during construction of the project, appropriate take authorization from CDFW pursuant to California Fish and Game Code Section 2081 subdivision (b) will be obtained. Compensatory mitigation will be provided for impacts on occupied habitat/floral resources for CBB (confirmed through surveys) at a replacement ratio of no less than 1:1. Compensatory mitigation will be provided at the offsite mitigation location through preservation of habitat, or through replacement of floral resources as close to their original location as is feasible.

Replaced floral resources may be split into multiple patches to meet distance requirements for multiple nests. These floral resources shall be maintained and replanted/managed as needed to ensure the replacement habitat is preserved.

Mitigation Measure BIO-3: Conduct Site Preparation and Construction Activities between September 1 and January 31 to Avoid the Typical Nesting Period of Migratory Birds, Raptors, or Bird Species of Special Concern and Implement Preconstruction Surveys and Protective Measures if Necessary
Site preparation and initial ground disturbance that require vegetation removal will occur between September 1 and January 31, outside the nesting period for migratory birds, raptors, or bird species of special concern nesting period (February 1 through August 31). Additionally, any demolition of structures will occur outside of the typical nesting period to avoid loss of birds that nest on structures (e.g., phoebes, swallows). If vegetation removal occurs outside the nesting period, no preconstruction survey will be required.

If construction activities must occur between February 1 and August 31 during the nesting period, ACTA Union City will retain a qualified wildlife biologist to conduct a survey for nesting raptors, and migratory birds, and bird species of special concern that may nest in any available habitats that will be removed during construction. Surveys will take place no more than 48 hours prior to vegetation removal and will cover all suitable raptor and migratory bird, raptor, or bird species of special concern nesting habitat that will be affected directly or any adjacent areas where nesting birds may be affected by construction noise or human presence. This includes areas potentially used by groundnesting migratory bird species.

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to the nesting bird. Buffers will remain in place as long as the nest is active or young remain in the area and are dependent on the adults. No construction activity of any type will be permitted within buffer zones. In general, the minimum buffer zone widths will be 300 feet for white-tailed kite and raptors, and 250 feet for migratory birds. Based on discussion with California Department of Fish and Wildlife (CDFW) DFG, buffer widths may be modified, depending on the proximity of activities to the nest(s) and whether the nest(s) will have a direct line of sight to construction activities, existing disturbance levels at the nest(s), local topography and vegetation, the nature of proposed activities, and the species potentially affected.

Mitigation Measure BIO-7: Prepare and Implement a Wetlands Mitigation Plan that Includes the Creation of New Wetlands, Waters of the United States and State, and Replacement and Enhancement of Willow Riparian Woodland and Scrub to Replace Permanent Loss
A plan for wetlands mitigation adjacent to and including Old Alameda Creek will be developed by qualified wetland botanists, wildlife biologists, hydrologists, engineers, and restoration ecologists.

The wetlands mitigation plan will include the creation and enhancement of wetlands, riparian vegetation, and linear aquatic features along Old Alameda Creek that will ensure no net loss of wetlands or waters of the United States or State and will provide mitigation for loss of riparian vegetation as a result of the proposed project. Impacts on wetlands or waters and required compensation will be developed based on the wetland delineation prepared for the proposed project (Appendix H) and in consultation with the Corps, CDFW, and RWQCB. ACTA Union City (for Quarry Lakes Parkway) will retain a qualified biologist to survey and flag willow riparian woodland and scrub that will be permanently affected by construction of the proposed project, and the mitigation plan will include replacement and enhancement of existing willow riparian woodland and scrub along Old Alameda Creek to ensure no net loss of willow riparian woodland and scrub.

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CEQA Addendum No. 1 4-25 April 2026
 creating an enhanced new open channel segment of the Line M Channel drainage alignment to extend to the continuous linear aquatic habitat of Old Alameda Creek;  grading new channel banks and regrading creek banks to create benches for additional waters, wetlands, and vegetation creating and enhancing wetland, channel, and riparian areas; and
 planting native wetland and riparian vegetation.

The wetlands mitigation plan will provide for mitigation in at least the following amounts (these amounts may change as necessary to meet permitting requirements):
 2:1 compensation for permanent loss of wetlands;
 1:1 compensation for permanent loss of channel if mitigation is on site and 2:1 compensation if mitigation is off site;
 1:1 compensation for permanent loss of riparian vegetation; and  0.1:1 compensation for any temporal loss of wetlands, waters (channel), and riparian vegetation.

The specific mitigation proposed for Quarry Lakes Parkway Project Phases 1 to 4 includes creation of a new Line M Flood Control Channel 712 feet long west of the existing Line M Flood Control Channel on site (as described in this document and reflected in current engineering plans) and offsite mitigation creating and enhancing wetlands, waters (channel), and riparian vegetation as described in the HMMP.

ACTA Union City (for Quarry Lakes Parkway) will be responsible for implementation of the wetlands mitigation plan, including construction and maintenance of the wetlands mitigation site until it is established based on permitting criteria. Post-construction maintenance responsibilities for the new Line M Flood Control Channel will be the subject of future agreements between and amongst ACTA, the cities of Fremont and Union City and the Alameda County Flood Control and Water Conservation District.

Post-construction maintenance responsibilities for the offsite mitigation will be secured by Union City through a contract with a mitigation developer. Once established, the mitigation site(s) will be self-sustaining.

A draft wetlands mitigation plan for the wetlands mitigation site is shown in Figure 3.3-

3. Mitigation acreages for affected habitats and linear feet for linear aquatic features are shown in Table 3.3-6. The specifics of the plan and the acreages will evolve over time as project details are finalized.

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CEQA Addendum No. 1 4-26 April 2026
mitigation plan, it is estimated to be 230,000 cubic yards of material. Thus, there would be secondary impacts from implementation of this mitigation, including loss of nonnative grasslands and riparian vegetation and increased air emissions.

Construction-related impacts have been addressed in this and other sections of the Draft EIR. However, it is anticipated that compensation for impacts on biological resources is included in this wetlands mitigation plan.

The wetlands mitigation plan includes creating an approximately 1,100- foot linear aquatic feature (open channel) adjacent and connected to the existing segment of Old Alameda Creek to provide 1:1 compensation for the loss of linear aquatic features (from culverting Line M Channel). The new open channel would begins on the south side of the new roadway at the outfall for the Line M Channel diversion pipeline, extends along the east side of Old Alameda Creek, and connects with Old Alameda Creek at its upstream end near the Line N-12 outfall. The new secondary channel will convey flow from the Line M Channel diversion pipeline into Old Alameda Creek.

The wetlands mitigation plan includes creating 2.7 acres of wetlands within the new secondary channel and in the upstream end of Old Alameda Creek to provide 2:1 compensation for the loss of wetlands and waters of the United States and waters of the States (from placing fill in Basin 2C, Old Alameda Creek, and Alameda Creek Flood Control Channel).

2.3 acres of willow riparian woodland and scrub would be restored (1:1 compensation) in areas temporarily disturbed by construction activities.

The wetlands mitigation plan will be supported by flow from the Line M Channel diversion pipeline, as well as from Line N-12, which currently enters Old Alameda Creek at its southernmost point near Quarry Lakes Drive. The Line M Channel diversion pipeline will discharge into a concrete dissipation structure located at the upstream end of the new secondary channel.

Conclusion
As presented in Table 4-4, the project overall, combining the roadway project effects in Union City and the mitigation area effects north of Livermore, would result in the permanent loss of wetlands (1.09 acres), waters (0.43 acre), riparian areas (0.28 acre), and upland nonnative grassland habitat for various species. As compensatory mitigation, the project would include creation of wetlands (approximately 3.40 acres at the offsite mitigation area), waters (approximately 712 linear feet/approximately 0.65 acre in the new Line M Line M Flood Control Channel and approximately 1,800 linear feet of channel at the

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CEQA Addendum No. 1 4-27 April 2026
offsite mitigation area), and riparian areas (approximately 1.0 acre at the offsite mitigation area); and preservation of approximately 18 acres of nonnative grassland habitat (at the offsite mitigation area). With implementation of Mitigation Measures BIO-1, BIO-2 (as revised), BIO-3 (as revised), BIO-7 (as revised), BIO-8 through BIO-12, HWQ-1, and HWQ-3, and with the proposed onsite and offsite compensatory mitigation, impacts on aquatic and upland habitats for common and rare species (including listed and candidate species) would be reduced to a less-than-significant level.

The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant impacts with mitigation. The redesigned project would not result in new significant effects or substantially more severe significant biological resources impacts compared to those disclosed in the EWC 2009 EIR, and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
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4.4 Cultural Resources
Table 4-5. Cultural Resources Environmental Checklist
Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Cultural Resources
CUL-1: Construction Impacts on
Archaeological Resources from Roadway
Widening.

LTSM
CUL-1
LTSM
CUL-1
No
CR-2: Construction Impacts on Historic
Resources from Roadway Widening.

LTS LTS No
CUL-3: Operational Impacts on Historic
Resources from Roadway Widening.

LTS LTS No
CUL-4: Construction Impacts on
Archaeological Resources from New
Roadway.

LTSM
CUL-1
LTSM
CUL-1
No
CUL-5: Change to Historic Resources
from New Roadway.

LTS LTS No
Changes in Cultural Resources Impact Analysis Relative to the EWC 2009 EIR A new review of the potential for archaeological resources and built-environment resources was conducted in 2025 for the QLP Phases 1–4 project (ICF 2025a, 2025b). No known archaeological resources were identified within the proposed improvements between Old Alameda Creek and Mission Boulevard (SR 238), which is the same conclusion as in the EWC 2009 EIR.

Regarding built resources, the EWC 2009 EIR identified one built-environment resource, the Peterson Farm House, as eligible for the National Register of Historic Places (NRHP) and the California Register of Historical Resources (CRHR) and as a CEQA cultural resource. The QLD realignment has been designed to avoid physical impacts on the Peterson Farm House. The only changes near the property would include removal of some vegetation and accessory structures outside the boundaries of the historic property. The historic property boundaries were revised in 2020, and no character‑defining features would be affected. 4 While the EWC 2009 EIR did not identify it at the time, a second built-environment historic resource, the Union Pacific Railroad (UPRR), is present in the project area and is also eligible for the NRHP and CRHR (ICF 2025b). As such, it is considered a historical resource under CEQA. The project would result in temporary construction impacts on a segment of the 4 For the Peterson Farmhouse located within the excess Route 84 state-owned property, Caltrans completed Historical Resources Compliance Report dated July 2020, followed by a Memorandum dated October 9, 2020 identifying the mitigation plan for future development of the site. The roadway project would not affect any character-defining features of this historic resource.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-29 April 2026
UPRR (the Niles Subdivision and Oakland Subdivision) and the tracks currently in the rightof-way; however, the historic property would continue to convey significance and there would be no impacts following conclusion of construction of the project. The project would only affect the existing tracks during construction when temporary shooflies would be necessary to reroute train traffic while the grade separations are constructed; following construction, the tracks would be restored to their original alignment, and the setting of the railroad would not permanently be changed in any substantial way. Therefore, identification of the UPRR as a CEQA cultural resource does not result in a new significant impact or a substantially more severe significant impact than disclosed in the EWC 2009 EIR.

Roadway Project Changes and Drainage Infrastructure Changes: The realignment of QLD would not change the level of impact on the Peterson Farm House compared to that disclosed in the EWC 2009 EIR because the realigned road would not affect or be substantially closer to the Peterson Farm House. The roadway changes relative to Osprey Drive, Lotus Pond Common, and the access road over the Line M Line M Flood Control Channel would not affect any known cultural resources, as there are no known resources at these locations. The 2-foot concrete wall, water quality basin, relocated Line M Line M Flood Control Channel, and change in the size of the Line M Overflow Pipeline would not affect cultural resources, as there are no known resources at these locations.

Offsite Mitigation: A cultural study was conducted by Peak & Associates, Inc. in 2025 of the offsite mitigation area; the report concluded that there are no known historical sites within the mitigation area (Olberding 2025).

Conclusion: The project, when considering the roadway improvements and the offsite mitigation area, would result in less-than-significant impacts with mitigation. Mitigation Measure CUL-1 includes monitoring by qualified archaeologists if resources are discovered.

The redesigned project would not result in new significant effects or substantially more severe significant impacts related to cultural resources compared to those disclosed in the EWC 2009 EIR, and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-30 April 2026

4.5 Geological Resources
Table 4-6. Geological Resources Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Geological Resources
GEO-1: Potential Structural Damage and
Injury Caused by Fault Rupture.

LTS LTS No
GEO-2: Potential Structural Damage and
Injury from Ground Shaking.

LTS LTS No
GEO-3: Potential Structural Damage and
Injury from Development on Unsuitable
Materials or Materials Subject to
Liquefaction.

LTS LTS No
GEO-4: Potential Accelerated Runoff,
Erosion, and Sedimentation from Grading
Activities.

LTS LTS No
GEO-5: Potential Structural Damage as a
Result of Development on Expansive
Soils.

LTS LTS No
Changes in Geological Resources Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes and Drainage Infrastructure Changes: As reported in the EWC 2009 EIR, the risk of surface fault rupture in the project alignment is low and liquefaction susceptibility maps have identified the project alignment as ranging from high to very high susceptibility, with soils between the UPRR lines as minimally to moderately susceptible to liquefaction. The proposed roadway and drainage project changes would occur in the vicinity of the original project alignment between Old Alameda Creek and Mission Boulevard (SR 238). The project refinements would not substantially alter the structural design of the project and would not have the potential to increase the risk of structural damage or injury from runoff, erosion, sedimentation, expansive soils, liquefaction, or lateral spreading and the geologic and soil features and types in the roadway change areas are the same as those identified in the EWC 2009 EIR. Moreover, the refined project would still be required to adhere to applicable BART, American Railway Engineering and Maintenance-of-Way Association, Caltrans, and Union City General Plan standards and building codes as identified in the EWC 2009 EIR.

Offsite Mitigation: The mitigation property is north of Livermore and is underlain by PlioPleistocene and Pliocene loosely consolidated deposits (QPc) and Quaternary alluvium and marine deposits (Q), as depicted on Figure 4-2 (USGS 2025; ESRI 2025). Construction activities at the site would include, but not be limited to, excavation and grading, construction of drainage features and wetlands, soil compaction, and plant installation.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-31 April 2026
Figure 4-2. Geological Formations at the Offsite Mitigation Area

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-32 April 2026
As stated in the EWC 2009 EIR, the San Francisco Bay Area is subject to moderate to high seismicity risk levels. According to the Alquist-Priolo Site Investigation Reports and available mapping tools, there are no active faults that pass through the mitigation property; therefore, the potential for fault rupture is considered relatively low. There are three Quaternary fault lines in the vicinity. One is approximately 5.5 miles northwest, another is approximately 3 miles southeast, and another is approximately 2.5 miles northeast of the mitigation area (CGS 2025).

The redesigned project would not include construction of new buildings or structures within the mitigation property. Therefore, no structures or individuals would be subject to potential damage or injury from runoff, erosion, sedimentation, expansive soils, liquefaction, or lateral spreading on site. Given this, the offsite mitigation area would not result in new or more severe significant geological or seismic impacts compared to those analyzed in the EWC 2009 EIR.

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant impacts. The redesigned project would not result in new significant effects or substantially more severe significant impacts related to geological resources and seismicity compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-33 April 2026

4.6 Hazards and Hazardous Materials
Table 4-7. Hazards and Hazardous Materials Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Hazards and Hazardous Materials
HAZ-1: Creation of a Hazard to the Public
or the Environment through the Routine
Transport, Use, or Disposal of Hazardous
Materials.

LTSM
HWQ-4
LTSM
HWQ-4
No
HAZ-2: Accidental Mobilization and
Exposure of Workers and Public to
Hazardous Materials during
Construction.

LTSM
HAZ-1, HAZ-2, PSR1
LTSM
HAZ-1, HAZ-2, PSR1
No
HAZ-3: Impairment of the
Implementation of or Physical
Interference with an Adopted Emergency
Response Plan or Emergency Evacuation
Plan during Construction.

LTSM
TRA-1
LTSM
TRA-1
No
HAZ-4: Exposure of People or Structures
to Increased Risk of Loss, Injury, or Death
involving Urban or Wildland Fires during
Construction.

LTSM
HAZ-3
LTSM
HAZ-3
No
HAZ-5: Emission or Use of Hazardous
Materials, Substances, or Wastes within

0.25 mile of an Existing or Proposed
School.

LTS LTS No
Changes in Hazards and Hazardous Materials Impact Analysis Relative to the EWC 2009 EIR
Roadway Project Changes and Drainage Infrastructure Changes: Construction of the redesigned project would result in similar impacts compared to the approved project including the potential accidental release of hazardous materials such as gasoline and diesel fuels, motor oil, gear lubricants, transmission fluids, hydraulic fluids, coolants, and degreasers. The roadway and drainage infrastructure changes would occur in the same general area as the approved project alignment between Old Alameda Creek to Mission Boulevard (SR 238).

Excavation for the relocated Line M Flood Control Channel where it encroaches into the Corp Yard could result in encountering contamination, as the EWC 2009 EIR disclosed that residual contaminated media may be present due to former activities at the Corp Yard.

Mitigation Measures HAZ-1 (requiring worker training and procedures) and HAZ-2 (requiring investigation and preparation of a Health and Safety Plan and a Soil and Groundwater

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-34 April 2026
Management Plan) would continue to apply to the revised project and are sufficient to reduce potential impacts to less-than-significant levels, consistent with the EWC 2009 EIR.

The redesigned project would not introduce new or increased risks related to hazardous material spills, accidental mobilization5 and exposure to hazardous materials, or damage or injury compared to those analyzed in the EWC 2009 EIR.

Offsite Mitigation: As shown in Table 3-2, the redesigned project would require substantially less excavation and fill compared to the approved project primarily due to the change from the previously approved onsite mitigation to the proposed offsite mitigation.

The redesigned project would construct and enhance wetlands and riparian habitat on the selected mitigation property north of Livermore, which consists of five undeveloped easement areas used in the past for ranching activities. Given their prior use, the likelihood of encountering hazardous materials during excavation for creation of new habitat is low.

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant impacts with mitigation. The redesigned project would continue to implement mitigation measures identified in the EWC 2009 EIR to minimize impacts related to hazardous materials or potential risk to people or property (Mitigation Measures HWQ-1, HAZ-2, HAZ3, HAZ-4, PSR-1, and TRA-1). The redesigned project would not result in new significant effects or substantially more severe significant impacts related to hazards and hazardous materials compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA. 5 Unintentional disturbance, movement, or release of contaminated soil or groundwater.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-35 April 2026

4.7 Hydrology and Water Quality
Table 4-8. Hydrology and Water Quality Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Hydrology and Water Quality
HWQ-1: Degradation of Surface Water
Quality from Construction-Related EarthDisturbing Activities.

LTSM
HWQ-1, HWQ-2,
HWQ-3
LTSM
HWQ-1, HWQ-2,
HWQ-3
No
HWQ-2: Contamination of Surface Water
Quality from Leak or Accidental Spill of
Hazardous Materials during
Construction.

LTSM
HWQ-4
LTSM
HWQ-4
No
HWQ-3: Increased Runoff from New
Impervious Surfaces and Adverse
Impacts on Surface Waters.

LTSM
HWQ-5, HWQ-6
LTSM
HWQ-5, HWQ-6
No
HWQ-4: Water Quality Impacts from
Discharges to CWA 303(d)-Listed Surface
Water Bodies-Diazinon.

LTS LTS No
HWQ-5: Potential Flood Hazards
Associated with Levee or Dam Failure.

LTS LTS No
Changes in Hydrology and Water Quality Impact Analysis Relative to the EWC 2009 EIR
Roadway Infrastructure Changes: The refined project would be located in the same general area as the approved project alignment between Old Alameda Creek and Mission Boulevard (SR 238). None of the roadway infrastructure changes would increase permanent encroachments into waterways or flood areas. The realignment of QLD relative to Osprey Drive, Lotus Pond Common improvements, and bicycle/pedestrian paths along 7th Street and Mission Boulevard would not occur in areas with waterways.

The removal of the existing access road over the Line M Flood Control Channel would result in temporary disturbance to the creek during construction; however, its removal would provide a permanent benefit by daylighting the creek at this location. Overall impervious surface area would be similar to that described in the EWC 2009 EIR, with the removal of the connection between Osprey Drive and QLD and the access road over the Line M Flood Control Channel offsetting the minor increase in pavement for the Lotus Pond Common/Alvarado-Niles Road intersection. Given this, the roadway infrastructure changes would not introduce new potential impacts related to hydrology and water quality that were not already analyzed in the EWC 2009 EIR.

Drainage Infrastructure Changes: The EWC 2009 EIR discussed construction of a new water basin, although the location of the basin had not yet been determined. The refined project

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-36 April 2026
proposes to construct a new water basin west of the realigned QLD roadway to treat roadway stormwater runoff. Once runoff is treated, it would be discharged into Old Alameda Creek.

A 2-foot concrete wall would be placed on an existing concrete pad at the outfall from Old Alameda Creek to the Alameda Creek Flood Control Channel. In addition, an outfall for the Line M Overflow Pipeline and the water quality basin would be located along Old Alameda Creek. These minor encroachments would not compromise the flow, flood capacity, or water quality of Old Alameda Creek. The relocation of the Line M Flood Control Channel would not compromise channel conveyance or water quality, as the new Line M Flood Control Channel would provide sufficient capacity consistent with the original design evaluated in the EWC 2009 EIR.

Given this, the drainage infrastructure changes would not result in new or more severe significant impacts related to hydrology and water quality that were not already analyzed in the EWC 2009 EIR.

Offsite Mitigation: Consistent with the approved project, the mitigation property would be within the San Francisco Bay hydrological unit. The redesigned project would create and enhance wetland, stream, and riparian habitat on the selected mitigation property.

Construction activities on site would include, but not be limited to, excavation and grading, construction of drainage features and wetlands, soil compaction, and plant installation.

Upon completion, the project would result in the conversion of 3.8 acres of nonnative annual grassland to wetland, channel, and riparian habitats. ENGEO prepared a Water Quality Analysis in October 2025 that analyzed water availability at the mitigation property (ENGEO 2025). ENGEO forecasts that the wetland areas would be dry for approximately 4 months out of the year between June and September. Saturated to near-saturated conditions are expected from October through May. This analysis confirmed the hydrologic feasibility of the proposed habitat features. Consistent with the approved project, the redesigned project would adhere to applicable regulations and associated permits to control construction-period water quality.

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant impacts with mitigation. The refined project would remain subject to applicable regulations and mitigation measures identified in the EWC 2009 EIR to reduce impacts on hydrology and water quality (Mitigation Measures HWQ-1, HWQ-2, HWQ-3, HWQ-4, HWQ-5, and HWQ-6). The redesigned project would not result in new significant effects or substantially more severe significant impacts related to hydrology and water quality compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-37 April 2026

4.8 Land Use and Planning
Table 4-9. Land Use and Planning Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact
Change in
Impact
Land Use and Planning
LUP-1: Division of an Established
Community.

LTS LTS No
LUP-2: Potential Conflict with the
Fremont General Plan.

LTS N/A. QLP Phases 1–4 do
not include project
components in Fremont.

N/A
LUP-3: Potential Conflict with the
Fremont Pedestrian Master Plan.

Beneficial N/A. QLP Phases 1–4 do
not include project
components in Fremont.

N/A
LUP-4: Potential Conflict with the
Fremont Bicycle Master Plan.

LTSM
LUP-1
N/A. QLP Phases 1–4 do
not include project
components in Fremont.

N/A
LUP-5: Potential Conflict with the
Alameda Countywide Bicycle Plan.

Beneficial Beneficial No
LUP-6: Potential Conflict with the Union
City General Plan.

LTS LTS No
LUP-7: Consistency with the Union City
Pedestrian and Bicycle Master Plan.

Beneficial Beneficial No
LUP-8: Consistency with the East Bay
Regional Park District Master Plan.

LTS LTS No
Changes in Land Use and Planning Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes: The roadway project changes would not result in new significant land use impacts or substantially more severe significant impacts because the overall impacts would be similar to or less than those described in the EWC 2009 EIR. The minor realignment of QLD would not notably alter the nature of project impacts because the project would be consistent with the Union City General Plan and the Station District Specific Plan (SDSP). Preservation of the proposed trail connection from QLD to Osprey Drive and removal of the previously proposed roadway connection at this location would be more consistent with existing land uses compared to the approved project, resulting in fewer conflicts and avoiding a roadway encroachment into Arroyo Park. Improvements at Lotus Pond Common would require minimal land acquisition (0.2 acre). Removal of the existing access road over the Line M Flood Control Channel would not require property acquisition beyond that described in the EWC 2009 EIR and would be consistent with adjacent development.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-38 April 2026
The redesigned project would be more consistent with the Union City General Plan policies and goals compared to the approved project by constructing additional bicycle and pedestrian trails. The redesigned project would construct a new trail on the east side of the realigned 7th Street from QLP to a point north of where Gregory Way meets 7th Street and along the west side of Mission Boulevard from QLP north to Holly Leaf Lane. These new pedestrian and bicycle trails would expand the growing network of trails throughout the city.

Drainage Infrastructure Changes: The refined project proposes to construct the water basin west of the realigned QLD roadway in approximately the same location as the previously proposed onsite mitigation area. The inclusion of a water quality basin on site would be consistent with the Union City General Plan public facilities goals and policies. The water quality basin would collect and treat stormwater runoff on site and would not introduce new land use conflicts compared to those analyzed in the EWC 2009 EIR. Relocation of the Line M Flood Control Channel would shift the proposed new segment of the Line M Flood Control Channel approximately 40 feet northwest, encroaching on the Corp Yard. The current bus parking area would need to be reconfigured but the reconfiguration can provide adequate parking to accommodate buses including electrified buses and onsite charging.

Therefore, no new land use conflict is identified compared to that disclosed in the EWC 2009 EIR.

Offsite Mitigation: The project would establish and enhance wetland and riparian habitats and preserve existing habitats within an offsite mitigation property north of Livermore in both Alameda County and Contra Costa County. Most of the mitigation area would be within unincorporated Alameda County Zoning District A (Agricultural) and the Alameda County General Plan land use designation is ECAP-RM (East County Area Plan Resource Management) (Alameda County 2025). The portion of the mitigation property in Contra Costa County would be in an unincorporated area of the county zoned A-80 (Exclusive Agriculture) with a land use designation of AL (Agricultural Lands) (Contra Costa County 2025). The existing properties consist of undeveloped open space with sparse agricultural development in the vicinity. Historically, the property has been used for dry farming and grazing purposes. No Williamson Act or Prime Farmland is within the mitigation property boundary (California Department of Conservation 2025). Implementation of the mitigation plan would entail creating and enhancing seasonal wetland and riparian habitat on site.

Once constructed, the project would result in the conversion of 3.8 acres of nonnative annual grassland to wetland, stream, and riparian habitats. Given this, the proposed use of the property would not conflict with present land use designations.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-39 April 2026
more severe significant impacts related to land use and planning compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-40 April 2026

4.9 Noise and Vibration
Table 4-10. Noise and Vibration Environmental Checklist Impact
Approved
Project Impact
Revised Project
Impact
Change in
Impact
Noise
NOI-1: Exposure of Offsite NoiseSensitive Land Uses to Short-Term Construction Noise from Roadway
Widening.

SU
NOI-1, NOI-2
SU
NOI-1 (revised), NOI-2
No
NOI-2: Exposure of Offsite VibrationSensitive Land Uses to Short-Term Construction Vibration from Roadway
Widening.

LTSM
NOI-3, NOI-4, NOI-5
LTSM
NOI-3, NOI-4, NOI-5
No
NOI-3: Exposure of Noise-Sensitive Land
Uses to Increased Traffic Noise from
Roadway Widening.

LTS LTS No
NOI-4: Exposure of Vibration-Sensitive
Land Uses to Increased Traffic Vibration
from Roadway Widening.

LTS LTS No
NOI-5: Exposure of Offsite NoiseSensitive Land Uses to Short-Term Construction Noise from New Roadway
and Wetlands Mitigation Site
Construction.

SU
NOI-1, NOI-2
SU
NOI-1 (revised), NOI-2
No
NOI-6: Exposure of Offsite VibrationSensitive Land Uses to Short-Term Vibration from New Roadway
Construction.

LTSM
NOI-2, NOI-3, NOI-4,
NOI-5
LTSM
NOI-2, NOI-3, NOI-4,
NOI-5
No
NOI-7: Exposure of Offsite NoiseSensitive Land Uses to Short-Term Increases in Railroad Noise during
Construction of the New Roadway Grade
Separation.

SU
NOI-2
SU
NOI-2
No
NOI-8: Exposure of Offsite NoiseSensitive Land Uses to Short-Term Increases in Railroad Vibration during
Construction of the New Roadway Grade
Separation.

SU
NOI-2, NOI-6
SU
NOI-2, NOI-6
No
NOI-9: Exposure of Noise-Sensitive Land
Uses to Operational Noise from Vehicles
on New Roadway.

LTSM
NOI-7, NOI-8, NOI-9
LTSM
NOI-8, NOI-9 (NOI-7
not applicable to QLP
Phases 1–4)
No
NOI-10: Exposure of Vibration-Sensitive
Land Uses to Increased Traffic from the
New Roadway.

LTS LTS No

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-41 April 2026
Impact
Approved
Project Impact
Revised Project
Impact
Change in
Impact
NOI-C1: Contribution to Cumulative
Impact on Noise-Sensitive Receptors
along Existing Roadways.

SU
NOI-C1, NOI-C2
SU
NOI-C1, NOI-C2
No
Changes in Noise and Vibration Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes: Construction of the revised roadway elements would occur within the same general area as the approved project between Old Alameda Creek and Mission Boulevard (SR 238). The only sensitive noise receptor near the realignment of QLD is the Peterson Farm House, and the realignment would not substantially change construction noise and vibration impacts at this historic residential farmhouse. Construction through Arroyo Park would be lessened through elimination of the roadway connection to Osprey Drive and retention of the trail connection only. Construction activity along Osprey Drive would have limited changes and would be similar in scale to the effort described in the EWC 2009 EIR to close its connection to Alvarado-Niles Road. Improvements at the Lotus Pond Common/Alvarado-Niles Road intersection would not be near any existing sensitive receptors. Construction of new bicycle and pedestrian trails along Mission Boulevard and 7th Street, and removal of the existing access road over the Line M Flood Control Channel, would temporarily increase construction activity at each location. While there are residences adjacent to the trail locations, construction will occur along existing active roadways; construction noise and vibration at any one location adjacent to a residence would be temporary and limited in scale.

Regarding the changes included in the QLP Phases 1–4 project, the only change with the potential to affect traffic noise levels is the elimination of the QLD to Osprey Drive connection and retention of the Osprey Drive to Alvarado-Niles Road connection rather than closing it as previously proposed. QLP drivers not accessing the Osprey Drive neighborhood would use QLP and Alvarado-Niles Road, which would be the same under the EWC design and the QLP Phases 1–4 project design. With the approved design, drivers to the neighborhood along Osprey Drive would use the QLP connection to Osprey Drive, whereas with the QLP Phases 1–4 project changes, they would instead use QLP, AlvaradoNiles Road, and Osprey Drive. This change would not increase traffic levels on Osprey Drive itself, but would shift the route of travel for Osprey Drive neighborhood drivers and would result in increased traffic levels on Alvarado-Niles Road between the intersections of QLP/ Alvarado-Niles Road and Osprey Drive/Alvarado-Niles Road relative to the configuration analyzed in the EWC 2009 EIR. There is one existing residence along this roadway segment, but it will be removed as part of the project. Compared to no-project conditions, the refined QLP Phases 1–4 project would reduce traffic levels along Osprey Drive, because it would eliminate through traffic using Osprey Drive between Alvarado-Niles Road and QLD, and

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-42 April 2026
traffic along Osprey Drive would only consist of local neighborhood traffic. Consequently, roadway noise along Osprey Drive would be less than under no-project conditions.

Drainage Infrastructure Changes: Construction of the modified drainage infrastructure elements would occur within the same general area as the approved project between Old Alameda Creek and Mission Boulevard (SR 238). Construction of a new concrete wall at the outlet from Old Alameda Creek would be minor and would occur within the Old Alameda Creek channel, which would limit the temporary noise experienced by residences to the south of the channel during construction. Construction of the onsite water quality basin would occur in the location previously proposed for the onsite waters/wetland/riparian mitigation, and excavation for the water quality basin would be much less than that required for the previously proposed onsite mitigation; therefore, this change would reduce construction noise and vibration relative to that disclosed in the EWC 2009 EIR.

Construction related to the relocation of the Line M Flood Control Channel would introduce additional construction noise impacts in the vicinity of the Corp Yard, but would not result in new significant or substantially more severe noise impacts on residential receptors compared to that in the EWC 2009 EIR because the shift in location is 40 feet to the north of the prior location which is actually moving further away from the nearest receptors to the construction area. There are no sensitive noise receptors at the temporary bus parking area along 11th Street. The reduction in the size of the Line M Overflow Pipeline would slightly reduce construction noise and vibration. Relocation of the outfall from the previously proposed mitigation area to within Old Alameda Creek would not result in any change in construction noise and vibration effects, as there are no sensitive receptors near either location.

Once operational, the changes in drainage infrastructure would result in no changes in operational noise or vibration compared to that disclosed in the EWC 2009 EIR.

Offsite Mitigation: The QLP Phases 1–4 project would establish and enhance wetland and riparian habitats and preserve existing habitats within an offsite mitigation property north of Livermore. The existing property consists of undeveloped open space with sparse development including two small ranch homes. The ranch homes are the closest noisesensitive receptors to proposed construction, approximately 40 and 290 feet from the mitigation boundary in Easement Areas 3 and 4. Restoration activities on the site would result in short-term construction noise impacts as a result of earthwork; however, there would be no long-term operational noise impacts compared to existing conditions.

Restoration activities will conform with requirements in the Alameda County Noise Element and Contra Costa County Ordinance Code, as described in revisions to NOI-1.

Conclusion: As presented in Table 3-2, overall project excavation and fill would be substantially reduced compared to the values reported in the EWC 2009 EIR, resulting in less construction noise and vibration from earthwork and fewer truck trips in the project

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-43 April 2026
area compared to that which would have resulted from the approved project. The redesigned project would be required to adhere to the mitigation measures identified in the EWC 2009 EIR to reduce impacts related to noise and vibration (Mitigation Measures NOI-1 (revised) through NOI-6, NOI-8, NOI-9, NOI-C1, and NOI-C2). Mitigation Measure NOI-7 is not applicable to the QLP Phases 1–4 project. The EWC 2009 EIR disclosed significant and unavoidable impacts of construction related to the new roadway (noise), onsite wetlands mitigation (noise), and grade separations (noise and vibration) and disclosed less-thansignificant impacts (with mitigation) related to operational noise and vibration. With the revised project, these conclusions from the EWC 2009 EIR are unchanged but the project changes would not result in new significant or substantially more severe significant noise and vibration impacts compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-44 April 2026

4.10 Population and Housing
Table 4-11. Population and Housing Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Population and Housing
POP-1: Indirect Inducement of
Substantial Population Growth.

LTS LTS No
POP-2: Displacement of a Substantial
Number of Existing Housing Units or
People.

LTS LTS No
Changes in Population and Housing Impact Analysis Relative to the EWC 2009 EIR
Roadway Project Changes and Drainage Infrastructure Changes: As reported in the EWC 2009 EIR, construction of the EWC overall would indirectly induce population growth in the project area by improving access between I-880 and Mission Boulevard (SR 238). While the QLP Phases 1–4 project would support planned growth consistent with the SDSP, it would not induce unplanned growth in the local vicinity. The refined project would not construct new housing and, as a result, would not directly induce population growth. The roadway and drainage infrastructure changes reflect minor design refinements that would not directly or indirectly affect regional population growth forecasted in the Union City General Plan or alter the residential displacements reported in the EWC 2009 EIR.

Offsite Mitigation: The refined project does not propose to construct any residential units, structures, or roadway improvements within the offsite mitigation property and would not displace any residences. The mitigation property would be used to construct and enhance wetland, stream, and riparian habitat. Given this, the change to offsite mitigation would not directly or indirectly induce population growth.

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in less-than-significant impacts related to population and housing. The redesigned project would not result in new significant effects or substantially more severe significant impacts related to population and housing compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-45 April 2026

4.11 Public Services and Utilities
Table 4-12. Public Services and Utilities Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact Change in Impact
Public Services and Utilities
PSR-1: Interruptions to Stormwater
Drainage System during Construction.

LTSM
PSR-1
LTSM
PSR-1
No
PSR-2: Adverse Effects on the Capacity of
Solid Waste Landfills.

LTS LTS No
PSR-3: Change in Demand for
Neighborhood Parks, Regional Parks, or
Recreational Facilities.

Beneficial LTS No
PSR-4: Adverse Physical Effects on
Existing Recreational Facilities.

LTSM
AES-4, NOI-2, TRA1
LTSM
NOI-2, TRA-1
(AES-4 no longer
applies)
Yes: Less
Changes in Public Services and Utilities Impact Analysis Relative to the EWC 2009 EIR
Roadway Project Changes: The refined project would result in reduced impacts on Arroyo Park compared to the EWC 2009 EIR, due to the removal of the Osprey Drive/Alvarado-Niles Road direct roadway connection. The refined design would only include a trail connection from Osprey Drive to QLP through Arroyo Park, which has a smaller footprint than the previously proposed roadway and is more consistent with recreational park uses than a roadway. Given this, the refined design would result in a beneficial impact on this existing recreational facility compared to the approved project. Adherence to Mitigation Measure AES-4 from the EWC 2009 EIR would no longer be required to mitigate project impacts. The roadway modifications would not result in new or increased demand for public services and utilities due to the minor nature of the refinements. The addition of bicycle/pedestrian paths along portions of 7th Street and Mission Boulevard would provide new recreational facilities compared to the approved project, which is beneficial.

Drainage Infrastructure Changes: Construction of the new concrete wall on the inlet to the outfall from Old Alameda Creek to the Alameda Creek Flood Control Channel would have no impacts on public services or utilities as none are present at this location.

The refined project proposes to construct a new water basin to treat roadway stormwater runoff west of the realigned QLD. Once runoff is treated in the water basin, it would be discharged into Old Alameda Creek. Similar to the approved project, the refined project would not result in the production of wastewater, either through construction activities or following project implementation. Therefore, the refined project would not require the

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-46 April 2026
construction of new infrastructure or expanded capacity of existing facilities for wastewater or public services provided along the project alignment. Furthermore, the refined project would be required to comply with Union City General Plan policies for public services, utilities, and service systems, and adhere to the California Integrated Waste Management Act and the Alameda County Integrated Waste Management Plans by preparing a Waste Management Plan prior to the onset of construction activities.

The refined project would relocate the Line M Flood Control Channel approximately 40 feet to the northwest into the Corp Yard, but the reconfiguration of bus parking would not change demand for public utilities and services. The slight reduction in the size of the Line M Overflow Pipeline would not alter the impacts reported in the EWC 2009 EIR.

Implementation of the refined project would improve drainage conditions along the project alignment and would result in similar impacts to those reported in the EWC 2009 EIR. Once constructed, the redesigned project would result in additional capacity to alleviate flooding (compared to existing conditions, but the same capacity as the approved project) and would not require expansion of other drainage infrastructure. During construction, conflicts with existing utility lines and temporary service interruptions with existing utility lines would be avoided to the extent feasible.

Offsite Mitigation: As depicted on Figure 3-17, the redesigned project would construct drainage features by excavating and grading sinuous, linear channels in formerly upland areas. These drainage features would be constructed to intercept surface runoff flowing across the slopes and would ultimately feed into seasonal wetlands constructed on the mitigation property. No additional drainage or expansion of existing utilities would be required.

The refined project would not include construction of residences or public service facilities within the mitigation property. Given this, offsite mitigation would not result in the need for additional services or the expansion of existing facilities for any public services, including fire and police protection, schools, parks, or other public facilities. As shown in Table 3-2, the refined project would substantially reduce the volume of excavation, fill, and amounts of material requiring reuse or offsite disposal compared to the approved project. Given this, the refined project would result in a beneficial impact on landfill capacity by reducing the volume of solid waste directed to landfills.

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Quarry Lakes Parkway Project: Phases 1–4
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services and utilities compared to those disclosed in the EWC 2009 EIR and would not trigger any other standards requiring further environmental review under CEQA.

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Quarry Lakes Parkway Project: Phases 1–4
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4.12 Transportation/Traffic
Table 4-13. Transportation/Traffic Environmental Checklist Impact
Approved Project
Impact
Revised Project
Impact
Change in
Impact
Transportation/Traffic
TRA-1: Temporary Increase in
Construction-Related Truck and Auto
Traffic, Decrease in Roadway Capacity,
and Disruption of Vehicular and NonMotorized Travel during Construction.

LTSM
TRA-1
LTSM
TRA-1
No
TRA-2: Intermittent Interruption of Rail
Service during Construction.

SU
TRA-2, TRA-3, TRA4
SU
TRA-2, TRA-3, TRA-4
No
TRA-3: Temporary Closure of Pedestrian
and Bicycle Trails during Construction.

LTSM
NOI-2, TRA-1
LTSM
NOI-2, TRA-1
No
TRA-4: Improvement in Operations at 12
Intersections and Minor Reduction in
Operations at 2 Intersections under
Proposed Project Conditions Compared
to No-Project Conditions in 2015.

LTS/Beneficial LTS/Beneficial No
TRA-5: Reduction in Operations at 18
Intersections under Proposed Project
Conditions Compared to No-Project
Conditions in 2015.

SU
TRA-5, TRA-6
SU
TRA-5 (TRA-6 is not
applicable to QLP
Phases 1–4)
No
TRA-6: Improvement in Operations at 21
Intersections under Proposed Project
Conditions and Minor Reductions in
Operations at 2 Intersections Compared
to No-Project Conditions in 2035.

LTS/Beneficial LTS/Beneficial No
TRA-7: Reduction in Operations at 16
Intersections under Proposed Project
Conditions Compared to No-Project
Conditions in 2035.

SU
TRA-5, TRA-6
SU
TRA-5 (TRA-6 is not
applicable to QLP
Phases 1–4)
No
Changes in Transportation/Traffic Impact Analysis Relative to the EWC 2009 EIR Roadway Project Changes: The roadway project changes would not result in new significant impacts or substantially more severe significant transportation or traffic impacts because construction effects would be addressed by mitigation identified in the EWC 2009 EIR, and the operational effects on traffic would be similar to those identified in the EWC 2009 EIR.

The realignment of QLD would not substantially change the location of construction or operational traffic. Temporary effects from construction along Osprey Drive would be

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Quarry Lakes Parkway Project: Phases 1–4
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reduced to a less-than-significant level by Mitigation Measure TRA-1, as in the EWC 2009 EIR.

The primary change in traffic conditions would be that the connection from Osprey Drive to Alvarado-Niles Road would remain open with the project changes and QLD would not connect to Osprey Drive. Operationally, this would mean that there would be less traffic along Osprey Drive than at present because there would be no connection to QLD and therefore less traffic turning at the intersection of Osprey Drive and Alvarado-Niles Road than under no-project conditions.
6 While there would be more traffic turning at the Osprey Drive/Alvarado-Niles Road intersection than under the approved project7 (which would eliminate the connection of Osprey Drive to Alvarado-Niles Road), there would be less than under no-project conditions due to elimination of through traffic to and from QLD. No significant level-of-service delays would be expected at this intersection due to this change in the roadway design compared to no-project conditions. With no connection of QLD to Osprey Drive, slightly higher amounts of traffic would travel along QLP from QLD to Alvarado-Niles Road compared to that in the EWC 2009 EIR, but this would only change the traffic volume at the new QLP/Alvarado-Niles Road intersection (which does not exist at present). Overall levels of traffic would not be different with the project changes, only the routing of some traffic to and from the neighborhood west of Osprey Drive along Osprey Drive, Alvarado-Niles Road, and QLP.

Temporary effects from construction along Lotus Pond Common would be reduced to a less-than-significant level by Mitigation Measure TRA-1. Lastly, removal of the access road over the Line M Flood Control Channel would not affect traffic, as this access road is only used for maintenance and not for public travel.

Drainage Infrastructure Changes: The drainage infrastructure changes would not result in new significant or substantially more severe significant transportation or traffic impacts because they would not substantially change construction traffic levels and would not affect operational traffic. While the relocation of the Line M Flood Control Channel into the southern part of the Corp Yard would affect some of the existing parking spaces, parking would be realigned to provide adequate capacity.

Offsite Mitigation: The offsite mitigation area would require construction traffic along North Livermore Road from I-580 north and along Manning Road. Any construction effects 6 Using EWC 2009 EIR traffic forecasts for 2035 no-project conditions, there would be an estimated 60 more vehicles (61 in the AM peak hour and 60 in the PM peak hour) using Osprey Drive to access Alvarado-Niles Road than the 1,500 to 1,600 vehicles (1,514 in the AM peak hour and 1,597 in the PM peak hour) using QLD east of Osprey Drive. This indicates that under no-project conditions, the traffic to and from QLD is the majority of the traffic on Osprey Drive between QLD and Alvarado-Niles Road at peak hours. 7 As noted, based on evaluation done after the EWC 2009 EIR, elimination of the intersection of Osprey Drive/Alvarado-Niles Road/Monterra Terrace would have had operational issues, which would be avoided with the changes in the refined QLP Phases 1–4 project.

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Quarry Lakes Parkway Project: Phases 1–4
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on traffic would be reduced to a less-than-significant level through Mitigation Measure TRA1. Operationally, the offsite mitigation area would include only minor traffic related to maintenance of the mitigation areas.

Changes in CEQA Requirements
Subsequent to completion of the EWC 2009 EIR, SB 743 (2013) required the Office of Planning and Research to implement change in CEQA transportation analysis away from measurements of traffic delay, such as level of service. The Office of Planning and Research ultimately proposed and approved requirements to use Vehicle Miles Travelled (VMT) instead and this requirement took effect in 2020 for new analyses. However, under CEQA, change in impact analysis requirements do not trigger the standards for supplemental environmental review under CEQA Guidelines section 15162 because they do not represent changes in a project nor are they physical changes in the environment. The lack of triggering supplemental review has been confirmed in multiple CEQA court rulings concerning GHG emissions and VMT. Furthermore, as discussed below, even if VMT were analyzed, the project changes would not result in a new or substantially more severe significant impact from the approved project.

Change in Conditions Since the EWC 2009 EIR: The EWC 2009 EIR forecasts of traffic were done in 2008 using 2005 data. Land use conditions and forecasted growth have changed several times since then. However, the forecasted traffic used in the EWC 2009 EIR for analysis of level of service for 2035 included robust growth and more recent forecasts have shown that the current forecasts for traffic in the project area are similar to those in the EWC 2009 EIR. As shown below in Table 4-14, current (2025) growth forecasts from Plan Bay Area 2050+ for the San Francisco Bay Area, Alameda County, Union City, and Fremont population and jobs are all lower than the projections at the time of the EWC 2009 EIR.

Consequently, the traffic analysis in the EWC 2009 EIR is based on a slightly higher level of forecasted growth than is presently expected to occur. The growth and related traffic levels projected in the EWC 2009 EIR may still occur in time, but it may be between 2035 and 2040 or later.

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Table 4-14. Comparison of Growth Projections at the Time of the EWC 2009 EIR and at Present Source Year(s)
SF Bay
Regional
Population
SF Bay
Regional Jobs
Alameda
County
Population
Alameda
County Jobs
Union City +
Fremont
Population
Union City +
Fremont Jobs
P2007 2005 7,096,100 3,449,640 1,505,300 730,270 280,800 113,320 P2007 2035 9,031,500 5,247,780 1,938,600 1,099,550 356,500 195,340 Growth Rate 2005–2035 27% 52% 29% 51% 27% 72%
Plan Bay Area 2050+ 2023 7,460,185 3,661,303 1,611,934 725,191 298,382 138,768 Plan Bay Area 2050+ 2035 8,476,301 4,855,101 1,884,601 994,120 350,466 150,426 Plan Bay Area 2050+ 2023–2035 14% 33% 17% 37% 17% 8%
Difference PBA 2050+
to P2007
2035 -6.1% -7.5% -2.8% -9.6% -1.7% -23.0%
Sources: ABAG 2007; ABAG/MTC 2025.

Fremont jobs projection for 2035 interpolated from PBA 2050+ 2023 to 2050 data due to anomalous 2035 estimate in PBA 2050+ data.

P2007 = Projections 2007; PBA = Plan Bay Area

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-52 April 2026
In 2020, Kittelson and Associates prepared a Transportation Memorandum that reviewed the EWC 2009 EIR analysis and conditions through 2020. Kittelson and Associates reviewed projections used in planning for the EWC 2009 EIR and compared 2005 calibrated base volumes at 31 intersections in the area to 2035 “with project” and “without project” scenarios (indicating the inclusion or exclusion of the EWC). The 2035 “without project” scenarios forecast growth by 2019 to be around 135,000 to 140,000 vehicles during the AM and PM peak periods. However, the model used for the Transportation Memorandum, based on 2017 projections indicated that 2019 volumes at these 31 intersections would be around 110,000 total vehicles during peak periods, nearly the same as the 2005 calibrated base from previous projections. This indicates very little growth in traffic volumes at these intersections between 2005 and 2019. Comparing individual intersections between 2005 and 2019 counts, the total volume among all 31 intersections showed a 2-percent increase in the AM peak period, a 7-percent decrease in the PM peak period, and a 2.5-percent decrease combining the two. Consequently, the EWC 2009 EIR forecast assumed much more substantial growth in traffic volumes than had actually occurred as of 2019.

The Transportation Memorandum also considered land use and growth forecasts at the time. Kittelson and Associates completed modeling scenarios with and without the respective projects included (for 2005–2035 from the EWC 2009 EIR and revised scenarios for 2019–2040 using 2017 projections). Figure 4-3 compares the results. The forecasts indicate the forecasted traffic volume growth with and without the project (green and blue lines, respectively) using the 2017 projections are lower than anticipated vehicular demand with and without the project in the EWC 2009 EIR (steeper dark blue and purple lines, respectively). The growth shown in the 2019–2040 projections indicates that travel demand is still forecasted to increase and to be served by the project.

With the COVID-19 pandemic and slow recovery, land use and growth forecasts have been reduced compared to forecasts prior to the pandemic, including the 2017 projections used for the Transportation Memorandum. Thus, the projections of traffic volume growth in the Transportation Memorandum are conservative and lower than present projections. The Transportation Memorandum’s conclusion that the highly robust forecasts for 2035 in the EWC 2009 EIR are not likely to be exceeded by 2035 still holds true with current (2025) forecasts, which are also lower than those in the EWC 2009 EIR for 2035. The forecasts in the EWC 2009 EIR still represent a reasonable long-term estimate for land use and traffic growth but they may be achieved later than 2035.

Per the Transportation Memorandum, based on the projections at the time, the project would accommodate expected growth and improve existing trip travel times but would not affect adjacent network saturation (i.e., regional traffic bottlenecks). Therefore, it is unlikely for the project to generate induced demand related to regional travel. The project would support a 3-percent reduction in vehicle hours traveled and an associated 6-percent

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Quarry Lakes Parkway Project: Phases 1–4
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reduction in vehicle hours of delay compared to 2040 forecasts. This general conclusion would not change when considering the 2025 projections.

Figure 4-3. Traffic Volume Growth Comparison, Study Intersections: AM and PM Peak Hours Source: Kittelson and Associates 2020.

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-54 April 2026
The reduction in delay with a corresponding reduction in VMT shows the project would improve local access and travel efficiency—serving primarily local trips and connections.

The project would provide a needed alternative route supporting network travel, with Decoto Road planned to become a transit-priority thoroughfare including bus rapid transit stations and supportive infrastructure (Kittelson and Associates 2020). These conclusions would not change when considering current (2025) forecasts, because the 2025 forecasts for 2035 are still less than in the EWC 2009 EIR.

With enhanced pedestrian and bicycle facilities, including a multi-use path with direct connection to the popular Alameda Creek trail system, the project would provide a link to the bicycle and pedestrian corridor from the Hillsides to the Dumbarton Bridge and link a series of East Bay regional parks. The facilities would also provide an alternative route to help reduce the collision risk for bicyclists relative to existing conditions (Kittelson and Associates 2020).

Conclusion: The project overall, combining the roadway project effects in Union City and the offsite mitigation area effects north of Livermore, would result in the same level of impact for each transportation impact as in EWC 2009 EIR (See Table 4-13). The redesigned project would adhere to the mitigation measures identified in the EWC 2009 EIR, including Mitigation Measures TRA-1 through TRA-5 and NOI-2 to reduce impacts on traffic and transportation (TRA-6 is not applicable to QLP Phases 1–4). The project changes would not result in new significant or substantially more severe significant transportation or traffic impacts compared to those disclosed in the EWC 2009 EIR because the changes would not substantially change traffic or transportation conditions relative to those predicted under the approved project and because the prior EIR’s analysis remains a reasonable estimate of long‑term conditions for the EWC program improvements. The project changes would not trigger any other standards requiring further environmental review under CEQA

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-55 April 2026

4.13 Cumulative Impacts
This section reviews the potential for the QLP Phases 1–4 project to result in new considerable contributions or substantially more severe significant contributions to cumulatively significant impacts compared to those disclosed in the EWC 2009 EIR. The analysis focuses on whether the incremental effects of the QLP Phases 1–4 project would be cumulatively considerable when viewed in connection with past, present, and reasonably foreseeable future projects. This section reviews the following:
 Current growth projection compared to that in the EWC 2009 EIR;  Current cumulative projects in the project vicinity compared to those in the EWC 2009 EIR;
 The specific changes in the QLP Phases 1–4 project relative to cumulative impacts; and  The potential for the changes in the QLP Phases 1–4 project to result in cumulative considerable contribution to cumulative impacts identified in the SDSP EIR.

Growth Projections
Growth projections were used for the cumulative impact analysis of traffic, air quality (traffic-related air quality), and noise (traffic noise). The EWC 2009 EIR used Association of Bay Area Governments (ABAG) projections, which included land use and sociodemographic data. At the time of the EWC 2009 EIR, the most recent projections were ABAG’s Projections 2007 (ABAG 2007). ABAG’s Projections 2007 relevant to the project area are compared to the latest ABAG/Metropolitan Transportation Commission projections in Plan Bay Area 2050+ from 2025 (ABAG/MTC 2025) as shown below in Table 4-14.

As shown in Table 4-14, the growth projections at the time of the EWC 2009 EIR were robust, indicating substantial growth by the horizon year of 2035 for the San Francisco Bay regional area, Alameda County, and Union City and Fremont. The latest projections prepared in 2025 for Plan Bay Area 2050+ estimate somewhat smaller population and job growth by 2035. Population growth for 2035 compared to that projected at the time of the EWC 2009 EIR is estimated to be 6 percent lower regionally, 3 percent lower in Alameda County, and 2 percent lower in Union City and Fremont. Job growth is estimated to be 7 percent lower regionally, 10 percent lower in Alameda County, and 23 percent lower in Union City and Fremont. The growth projections are influenced by overall trends in the economy, and therefore the current estimates, compared to those at the time of the EWC 2009 EIR, have been affected by the Great Recession of 2007 to 2009 and the subsequent recovery, as well as the COVID-19 pandemic of 2020 to 2022 and the following recovery.

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Quarry Lakes Parkway Project: Phases 1–4
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While the current projections are lower, as shown in Table 4-14, substantial growth in population and jobs is still expected. If the current projections end up being realized, then the growth expected in the EWC 2009 EIR would be realized several years later than 2035, perhaps by 2040. Nevertheless, the EWC 2009 EIR’s analysis of cumulative effects using land use projections remains valid, as the analysis considers the long-term growth in the project area and the region, although the growth may occur some years later than previously estimated. Importantly, the growth projections used in the EWC 2009 EIR do not underestimate potential growth, and therefore the impact analysis does not underestimate the potential cumulative environmental effects associated with operational air quality, operational traffic noise, and operational traffic, as the project effects and cumulative effects for these topics are directly related to traffic levels which are driven by socioeconomic growth. No new significant impacts or any substantially more severe significant impacts are identified relative to changes in growth projections used for the cumulative analysis.

List of Cumulative Projects
Cumulative analysis of all other areas was based on a list of projects that at the time were underway, approved, or planned in the project vicinity. Figure 4-4 shows the projects used in the EWC 2009 EIR analysis (Figure 4-1 from the EWC 2009 EIR). As shown on Figure 4-4, the EWC 2009 EIR anticipated that all the undeveloped areas, as well as the former Pacific States Steel site, would experience cumulative development. For the QLP Phases 1–4 project, the relevant projects in this figure are the projects in Union City (Projects #17 to #24), which are discussed further below, because these are the projects that have the potential to contribute to cumulative impacts due to proximity to the QLP Phases 1–4 project. All the areas identified with potential cumulative projects in the EWC 2009 EIR, with one exception, are part of the SDSP, which was adopted in 2022. As shown in Table 4-15, only one of the cumulative projects in the EWC 2009 EIR was built between 2009 and 2025.

Consequently, the expectation of development in all the adjacent areas today is the same as in the EWC 2009 EIR, with the exception of the one project that has already been developed. The land uses proposed in the SDSP area are shown on Figure 4-5.

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Quarry Lakes Parkway Project: Phases 1–4
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Figure 4-4. Cumulative Projects in the Project Area (from the EWC 2009 EIR)

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Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-58 April 2026
Table 4-15. Cumulative Projects in the QLP Phases 1–4 Project Area from the EWC 2009 EIR and Current Status
# and Name
Project Description in EWC
2009 EIR
Current Status/Station District Specific
Plan Land Use Designation
17 Station District Redevelopment to provide
residential, office space,
commercial, expanded train
station, and parks
Part of SDSP Core Area and now
designated for mixed-use commercial and
open space. Not yet built.
18 Air Liquide Redevelopment to increase
density of light industrial and
add commercial
Part of SDSP Station East Area and
designated partially for civic facility and
partially for mixed-use residential. Not yet
built.
19 Avalon Bay at
Union Station
Multifamily units near BART
station
Constructed.
20 Unnamed 7th
Street site
Redevelopment to increase
density of light industrial
Part of SDSP Station East Area and
designated for mixed-use residential. Not
yet built.
21 Catellus/Shelton Redevelopment to increase
density of light industrial site
Part of SDSP Station East Area and
designated for mixed-use residential. Not
yet built.
22 Island Redevelopment to increase
density of light industrial
Part of SDSP Station East Area and
designated for Employment (commercial,
office, laboratory, light manufacturing).

Not yet built.
23 Pacific States
Steel Corporation
Site
Redevelopment to allow for
light industrial
Part of SDSP Core Area and designated for
mixed-use commercial. Not yet built.
24 Caltrans Property Residential and park Now owned by Union City. Part of SDSP Gateway Area and designated for open
space along QLP, residential east between
Alvarado-Niles Road and the new
realigned QLD, and civic facility along
Alvarado-Niles Road. Not yet built.

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Figure 4-5. Station District Specific Plan Proposed Land Uses Source: City of Union City 2022.

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CEQA Addendum No. 1 4-60 April 2026
Changes Associated with the QLP Phases 1–4 Project
The EWC 2009 EIR disclosed cumulative impacts related only to construction air quality, cultural resources, operational noise, and transportation/traffic. These are reviewed below relative to the changes included in the QLP Phases 1–4 project.

Construction Air Quality
The EWC 2009 EIR identified that construction of the roadway project could result in potential significant unavoidable construction emissions, even with mitigation, and would contribute to cumulative air quality impacts. As discussed in Section 4.2, Air Quality, the EWC 2009 EIR’s conclusion is unchanged with the changes to the QLP Phases 1–4 project, which would involve a similar level of roadway construction as disclosed in the EWC 2009 EIR. However, with the change to offsite wetland/water mitigation, the QLP Phases 1–4 project would require substantially less excavation (196,000 fewer cubic yards), import of fill (19,000 fewer cubic yards), and off haul/reuse/recycling of soil (176,000 fewer cubic yards) than disclosed in the EWC 2009 EIR. As a result, construction emissions would be less than disclosed in the EWC 2009 EIR but may still be significant and unavoidable. The QLP Phases 1–4 project contribution to cumulative emissions would be the same or less than previously disclosed in the EWC 2009 EIR.

Cultural Resources
The EWC 2009 EIR identified that although no known archaeological resources were present in the project area, construction activities could encounter undiscovered archaeological resources, and this potential was identified as a significant cumulative impact. As discussed in Section 4.4, Cultural Resources, no known archaeological resources have been identified in the roadway project area or the offsite mitigation area. In addition, the reduced excavation associated with the QLP 1–4 project would further reduce the potential for disturbance of unknown resources. While the potential to encounter undiscovered archaeological resources would remain, the QLP 1–4 project’s contribution to cumulative impacts related to archaeological resources would be no greater than that identified in the EWC 2009 EIR.

The EWC 2009 EIR described that none of the cumulative projects anticipated at that time would affect the Peterson Farm House. As noted below in the analysis of the SDSP cumulative impacts, development in the Gateway Area may result in demolition of the Peterson Farm House. As discussed in Section 4.4, the QLP Phases 1–4 project would not result in a significant impact on the Peterson Farm House. Consequently, while SDSP buildout may result in a significant impact on this historic resource, the QLP Phases 1–4 project would not contribute considerably to that cumulative impact.

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Operational Noise
The EWC 2009 EIR described that the EWC project would contribute to significant cumulative noise impacts in noise-sensitive areas along existing roadway segments on Decoto Road, Paseo Padre Parkway, and Alvarado-Niles Road from increased traffic.

Mitigation measures were identified to reduce this impact, but the EWC 2009 EIR identified that the mitigation was not sufficient to reduce the impact to a less-than-significant level.

As noted, the current growth projections and traffic volumes along roadways in the project vicinity are projected to be lower than disclosed in the EWC 2009 EIR, and therefore traffic levels and traffic-related noise are not expected to increase due to changed circumstances.

Regarding the changes included in the QLP Phases 1–4 project, the only change that has the potential to affect traffic noise levels is elimination of the connection of QLD to Osprey Drive and retention of the Osprey Drive connection to Alvarado-Niles Road. This change would alter routing for Osprey Drive neighborhood traffic but would not increase traffic volumes on Osprey Drive itself. Although traffic volumes on a short segment of Alvarado‑Niles Road would increase slightly relative to the EWC 2009 EIR, there are no noise‑sensitive receptors along this segment. Therefore, the QLP Phases 1–4 project would not result in new significant noise impacts or a cumulatively considerable contribution to cumulative noise impacts compared to those disclosed in the EWC 2009 EIR.

Transportation/Traffic
The EWC 2009 EIR identified significant cumulative traffic level‑of‑service impacts at certain existing intersections along Decoto Road, Mission Boulevard, Paseo Padre Parkway, Fremont Boulevard, Thornton Avenue, Niles Boulevard, and Alvarado-Niles Road, and identified that mitigation measures would only be able to reduce impacts at some of the affected intersections to a less-than-significant level. As noted, the lower growth projections and reduced traffic volumes along roadways in the project vicinity indicate that overall traffic conditions would not be worse than those disclosed in the EWC 2009 EIR due to changed circumstances.

For the QLP Phases 1–4 project, the only change that has the potential to affect traffic levels is eliminating the connection of QLD to Osprey Drive and keeping the Osprey Drive connection open to Alvarado-Niles Road instead of closing it, as described in the EWC 2009 EIR. As discussed in Section 4.12, residents along Osprey Drive would need to use Osprey Drive, Alvarado-Niles Road, and QLP in lieu of the direct connection to QLD analyzed in the EWC 2009 EIR. While this change would result in additional neighborhood traffic to and from the Osprey Drive/Alvarado-Niles Road intersection, it would eliminate through traffic on Osprey Drive due to drivers using Osprey Drive between Alvarado-Niles Road and QLD, resulting in a reduction of traffic at the Osprey Drive/Alvarado-Niles Road intersection.

Therefore, this change is not expected to result in a new considerable contribution to a

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-62 April 2026
significant impact or a substantially more severe contribution to a significant impact related to traffic compared to that disclosed in the EWC 2009 EIR.

Consequently, the QLP Phases 1–4 project would not result in a cumulatively considerable contribution to cumulative traffic impacts beyond those identified in the EWC 2009 EIR.

Other Subject Areas
Except for the topical areas previously discussed (air quality, cultural resources, operational noise, and transportation/traffic), which were identified in the EWC 2009 EIR as having cumulative impacts, the remaining environmental topic areas did not identify cumulative impacts in the EWC 2009 EIR. For those remaining topic areas, changes associated with the QLP Phases 1–4 project and changes in circumstances would not result in new significant impacts or substantially more severe significant impacts compared to those disclosed in the EWC 2009 EIR. Accordingly, no changes are identified that would alter the project’s cumulative impact conclusions as disclosed in the EWC 2009 EIR.

Station District Specific Plan EIR and the QLP Phases 1–4 Project The SDSP EIR (City of Union City 2022) analyzed cumulative effects of buildout of the SDSP area, including all of the undeveloped land adjacent to the QLP Phases 1–4 project as well as additional infill development elsewhere within the SDSP area. The QLP is considered an approved project in the SDSP EIR. The conclusions of the SDSP EIR were that there would be no additional significant cumulative environmental effects from buildout of the SDSP combined with other planned development (City of Union City 2022). The SDSP EIR did identify that buildout of the SDSP itself would result in the six significant and unavoidable impacts discussed below. The potential for the changes in the QLP Phases 1–4 project to contribute considerably to cumulative impacts with the SDSP is analyzed below for these six impacts.
 Scenic Vista: The SDSP EIR describes that the views of the foothills of the Coastal Range (i.e., hillside area) that frame the eastern edge of the city are considered scenic vistas and the development of buildings up to 160 feet in height in the Core subarea would obstruct views of the hillside area. While policies in the 2040 Union City General Plan and the SDSP together with associated zoning standards would reduce these impacts to the maximum extent practicable, there are no mitigation measures available to entirely avoid impacts on scenic vistas. As such, this impact would remain significant and unavoidable for the SDSP. The QLP Phases 1–4 project would not result in substantial changes to the aesthetic impacts identified in the EWC 2009 EIR because it would not change the elevation of roadway features and would not result in new roadway development in substantially different locations than those discussed in the EWC 2009 EIR. Consequently, the QLP Phases 1–4 project would not contribute considerably to a cumulatively significant aesthetic impact with the SDSP.

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-63 April 2026
 Construction Air Quality: The SDSP EIR describes that construction of new development within the Station District may result in emissions of reactive organic gases, oxides of nitrogen, and particulate matter smaller than 2.5 microns in excess of Bay Area Air Quality Management District (BAAQMD) thresholds, even with mitigation. The EWC 2009 EIR made a similar conclusion regarding construction of the roadway project and potential significant unavoidable construction emissions. The EWC 2009 EIR conclusion is unchanged with the changes to the QLP Phases 1–4 project, which would have a similar amount of construction for the roadway project as disclosed in the EWC 2009 EIR. However, with the change to offsite wetland/water mitigation, the QLP Phases 1–4 project would require far less excavation (196,000 fewer cubic yards), import of fill (19,000 fewer cubic yards) and off haul/reuse/recycling of soil (176,000 fewer cubic yards) than disclosed in the EWC 2009 EIR, and therefore construction emissions overall would be less than disclosed in the EWC 2009 EIR but may still be significant and unavoidable. The QLP Phases 1–4 project’s contribution to cumulative emissions would be the same or less than previously disclosed in the EWC 2009 EIR.  Operational Air Quality: The SDSP EIR describes that although policies and the overall approach of the SDSP—which fosters bicycle and pedestrian infrastructure and supports sustainable land use patterns including mixed-use design and increased density—would reduce the severity of criteria pollutants, buildout of the SDSP would nevertheless generate long-term operational emissions in excess of BAAQMD’s project-level thresholds. Accordingly, operational criteria pollutant emissions associated with development under the SDSP would potentially result in a significant impact on air quality that would remain significant and unavoidable with mitigation. The EWC 2009 EIR identified that operational emissions associated with the EWC would have a lessthan-significant impact and the QLP Phases 1–4 project would not contribute considerably to cumulative operational air quality impacts with the SDSP.  Emissions Exposure to Sensitive Receptors: The SDSP EIR describes that even with the SDSP policies and mitigation measures, additional emissions generated by new stationary sources, vehicle trips, and construction activity could expose sensitive receptors to cancer and non-cancer risks in excess of the BAAQMD significance thresholds. Mitigation measures would reduce health risks, but impacts would remain significant and unavoidable. The EWC 2009 EIR analyzed mobile-source air toxics (MSATs) associated with the EWC, concluding that with or without the EWC, in the design year (2035), MSAT emissions would be reduced in the immediate project alignment, relative to the no project alternative, as a result of the reduced VMT associated with more direct routing, and the U.S. Environmental Protection Agency’s MSAT reduction programs. As discussed in Section 4.12, Transportation/Traffic, the EWC is still expected to reduce VMT, as disclosed in the EWC 2009 EIR. Consequently, the QLP

4. Evaluation of Environmental Impacts
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 4-64 April 2026
Phases 1–4 project would not contribute considerably to cumulative operational emissions exposure to sensitive receptors with the SDSP.  Cultural Resources: The SDSP EIR describes that buildout of the Gateway Area of the SDSP may result in demolition of the Peterson Farm House, which is a historic resource.

As disclosed in Section 4.4, Cultural Resources, the QLP Phases 1–4 project would not have a significant effect on the Peterson Farm House. Therefore, while the SDSP may result in a significant impact on the Peterson Farm House, the QLP Phases 1–4 project would not contribute considerably to that impact.
 Greenhouse Gas Emissions: The SDSP EIR describes that while the SDSP would be consistent with policies and plans that encourage energy conservation, energy efficiency, and sustainability, even with mitigation, development under the SDSP would result in significant and unavoidable impacts related to operational GHG emissions. The QLP Phases 1–4 project’s operational emissions would be related to VMT. As discussed in Section 4.12, Transportation/Traffic, the EWC is still expected to reduce VMT as disclosed in the EWC 2009 EIR with the changes included in the QLP Phases 1–4 project.

Consequently, the QLP Phases 1–4 project would not contribute considerably to cumulative GHG emissions of the SDSP.
 Vehicle Miles Traveled (informational disclosure only): The SDSP EIR describes that while the SDSP would include goals, policies, and a land use pattern designed to reduce VMT, the project would still result in a significant and unavoidable VMT impact. The change in the State CEQA Guidelines per Senate Bill 743 regarding VMT occurred in 2020, after the EWC 2009 EIR was certified, and this is therefore not an issue for the QLP Phases 1–4 project. For informational purposes only, it is noted, as disclosed in Section 4.12, Transportation/Traffic, the EWC is expected to reduce VMT with the changes included in the QLP Phases 1–4 project as it was expected to reduce VMT in the EWC 2009 EIR.

Consequently, the QLP Phases 1–4 project would not contribute considerably to cumulative operational VMT with the SDSP.

Conclusion
The changes associated with the QLP Phases 1–4 project and changes in circumstances would not result in new considerable contributions to significant cumulative impacts or substantially more severe contributions to significant cumulative impacts compared to those disclosed in the EWC 2009 EIR, and would not trigger any other standards requiring further environmental review under CEQA.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 5-1 April 2026

5. References
Alameda County. 2025. Unincorporated Alameda County Public Access Map. Available:
https://www.arcgis.com/home/item.html?id=303ba7fe78934234ac3c42af53754c43.

Accessed January 2026.

Alameda County Transportation Authority (ACTA). 2009. Final Environmental Impact Report (SCH #2007102078). Prepared by ICF. April. Available: https://www.alamedactc.org/wpcontent/uploads/2018/12/00703-07_RevisedFEIR_V1_2009_Web.pdf. Accessed December 13, 2025.

Association of Bay Area Governments (ABAG). 2007. Projections 2007 (P2007).

Association of Bay Area Governments (ABAG)/Metropolitan Transportation Commission (MTC). 2025. Plan Bay Area 2050 + Final Blueprint Land Use Traffic Analysis Zone (TAZ) Data.

California Department of Conservation. 2025. Williamson Act Enrollment Finder. Available:
https://maps.conservation.ca.gov/dlrp/WilliamsonAct/App/. Accessed December 2025.

California Department of Fish and Game (CDFG). 2012. Staff Report on Burrowing Owl Mitigation. March. Available:
https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/JVR/AdminRecord/IBR/R TCReferences/3a%20CDFG%202012_Staff%20Reports%20on%20Burrowing%20Owl%20 Mitigation.pdf. Accessed April 2026.

California Department of Fish and Wildlife (CDFW). 2025. Natural Diversity Data Base (CNDDB). Computer listings and map locations of historic and current recorded occurrences of special-status species and natural communities of special concern for USGS 7.5-minute quadrangle maps.

California Geological Survey (CGS). 2025. Alquist-Priolo Site Investigation Reports. Available:
https://maps.conservation.ca.gov/cgs/informationwarehouse/apreports/. Accessed December 2025.

City of Union City. 2022. Station District Specific Plan Environmental Impact Report.

Prepared for the City of Union City. Available:
https://www.unioncityca.gov/423/Resources. Accessed February 2026.

5. References
Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 5-2 April 2026
Contra Costa County. 2025. CCMAP. Available:
https://www.arcgis.com/apps/webappviewer/index.html?id=92d542bcb39247e8b5580 21bd0446d18. Accessed December 2025.

ENGEO. 2025. Quarry Lakes Parkway Mitigation Area Water Availability Analysis. Prepared for City of Union City. October.

Environmental Systems Research Institute (ESRI). 2025. Soil Survey Map. Available:
https://www.arcgis.com/apps/View/index.html?webmap=38a93357a08b4f6d94d7e07a 424fafd5. Accessed December 2025.

HDR. 2024. Final Drainage Report. Quarry Lakes Parkway Multi Modal Transportation Corridor Project (Phases 1 to 4). Prepared for City of Union City. November 28.

ICF. 2025a. Archaeological Survey Report for Quarry Lakes Project Phases 1 to 4, from Mission Boulevard to Old Alameda Creek (City Project No. 18-04), Alameda, California.

Prepared for City of Union City. November.
———. 2025b. Historic Architecture Survey Report and Finding of Effect, Quarry Lakes Parkway Project Phases 1 through 4, from Mission Boulevard to Old Alameda Creek (City Project No. 18-04) Alameda County, California. Prepared for City of Union City.

November.

Kittelson and Associates. 2020. Quarry Lakes Parkway, City Project #18-04, Transportation Memorandum. Prepared for City of Union City. October. Available:
https://www.unioncityca.gov/DocumentCenter/View/4496/23493_QLP-TransportationMemo_10-22-2020. Accessed December 13, 2025.

Mark Thomas. 2025. Quarry Lakes Parkway Phases 1 to 4, 35% Design Drawings, Phase 1 65% Design Drawings, and Phase 2 95% Design Drawings. Prepared for City of Union City.

Olberding Environmental, Inc. (Olberding). 2026. Habitat Mitigation and Monitoring Plan for the Quarry Lakes Parkway City Project No. 18-04 Management Area, Alameda and Contra Costa Counties, California. Prepared for the City of Union City. April.

U.S. Geological Survey. 2025. National Geologic Map Database MapView. Available:
https://ngmdb.usgs.gov/mapview/?center=-121.79,37.757&zoom=15. Accessed December 2025.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-1 April 2026
Attachment A: Description of Current Quarry Lakes Parkway Phases 1 to 4 Project
The project would be implemented in useable segments and full-funded phases. Elements included in each phase are summarized below. The following sections discuss each of the different elements by type.

A-1: Description of the QLP 1–4 Project by Phases
Phase 1: 7th Street to Mission Boulevard (SR 238)
Phase 1 would construct a new roadway with landscaped median, buffered Class II bike lanes, sidewalk with a separated Class I multi-use trail between 7th Street and Mission Boulevard (SR 238). 7th Street would be realigned to curve west fronting the Corp Yard and the new parking lot. This phase would implement improvements at the Mission Boulevard (SR 238) intersection and a new signalized intersection at 7th Street and Chesapeake Drive.

Figure A-1 shows an overview of Phase 1.
 Mission Boulevard (SR 238) intersection: This phase would include widening of Mission Boulevard, adding two left-turn lanes from northbound Mission Boulevard to the new QLP Phases 1–4 project, two right-turn lanes from southbound Mission Boulevard to the QLP Phases 1–4 project at the intersection of Mission Boulevard (SR 238), and associated drainage improvements. This new connection with Mission Boulevard would improve overall traffic circulation throughout the corridor and provide new access for residents into Appian Way.
 Connection to the Corp Yard and Drigon Park: Phase 1 would realign 7th Street, provide a formalized intersection with improved access for residents into Chesapeake Drive, and provide additional parking for the Corp Yard and Drigon Park. This would also include construction of a new sidewalk along the west leg to create a three-leg intersection.  Realignment of Line M Flood Control Channel: Phase 1 would construct a new Line M Flood Control Channel, overflow structure, and box culvert. This phase involves all 7th Street and QLP Phases 1–4 project drainage improvements within phasing limits to connect to the new culvert. This phase would include installation of the gravity flowing Line M Overflow Pipeline from Line M Flood Control Channel to Alvarado Niles Road.  This phase would include reconfiguration of the Corp Yard due to the encroachment of the realigned Line M Flood Control Channel into the southern part of the Corp. Yard and reconstruction of the Corp Yard security wall.

Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-2 April 2026
Figure A-1. Quarry Lakes Parkway Phase 1 Overview
Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-3 April 2026
 Drainage facilities: This phase would construct water quality bioretention areas adjacent to the proposed sidewalks and within the proposed parking lot. These water quality bioretention areas would provide treatment and hydromodification mitigation for Phase 1 before discharging to the Line M Flood Control Channel.  A new Class I multi-use trail would be added along the west side of Mission Boulevard (SR 238) from Holly Leaf Drive to Quarry Lakes Parkway.  The new right of way needed for new QLD and the realigned Line M Flood Control Channel would require relinquishment and/or acquisition of properties owned by Alameda County and City of Union City.

Phase 2: Old Alameda Creek to Alvarado-Niles Road
Phase 2 would construct a new roadway with landscaped median, buffered Class II bike lanes, sidewalk with a separated Class I multi-use trail between Old Alameda Creek and Alvarado-Niles Road. It would realign QLD from Quarry Lakes Regional Recreation Area landscaped median, buffered Class II bike lanes, sidewalk with a separated Class I multi-use trail to the new QLP and create a new intersection with QLD. This phase would also include construction of a new outfall to Old Alameda Creek and a water quality basin. Figure A-2 shows an overview of Phase 2.
 Alvarado-Niles Road intersection: This phase would construct the QLP and AlvaradoNiles Road intersection as four-leg intersection with associated drainage improvements.

It would connect to the existing sidewalk on the north side of the new intersection, and a new multi-use path would be provided on the south side.  QLD intersection and QLD realignment: This phase would realign QLD from Quarry Lakes Regional Recreation Area to the new QLP. It would construct a new two-leg QLP and QLD intersection while limiting roadway and streetscape improvements along the south leg and ending earthwork limits before Old Alameda Creek. All improvements would be located along QLD and the roadway between the proposed water quality basin and QLP.  Monterra Terrace/Osprey Drive/Alvarado-Niles Road intersection: Phase 2 would include modifications to the intersection and traffic signal at the Monterra Terrace/ Osprey Drive intersection.
 Modification and signalization of the intersection of Alvarado-Niles Road and Lotus Pond Common: This phase would change the existing intersection to a more perpendicular configuration by realigning Lotus Pond Common where it meets Alvarado-Niles Road and the intersection will be signalized.

Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-4 April 2026
Figure A-2. Quarry Lakes Parkway Phase 2 Overview
Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-5 April 2026
 Drainage facilities:
o Line M Overflow Pipeline: This phase would construct the portion of the 60-inch reinforced concrete pipe (RCP) overflow pipe from east of Alvarado-Niles Road to Old Alameda Creek. The pipeline would convey Line M diversion flows and discharge to Old Alameda Creek approximately 100 feet southwest of the new QLP/QLD intersection. The outfall would include construction of a headwall, wingwalls, flap gates, and rock slope protection.
o Water quality basin: Phase 2 would construct a water quality basin south of QLD to provide stormwater treatment for roadway and adjacent new development runoff.

The water quality basin would discharge to Old Alameda Creek at the same outfall as the Line M Overflow Pipeline. Old Alameda Creek would provide hydromodification mitigation for stormwater runoff from the roadway and new development. o BMPs, pump station, and drainage facilities: This phase would include construction of drainage improvements south of Alvarado-Niles Road that would connect to a new pump station (Pump Station #2) to be constructed near the QLD/QLP intersection, just west of the water quality basin. The new pump station would be activated during water quality storm events to convey runoff to the water quality basin.

Phase 3: 11th Street to 7th Street
Phase 3 would construct a new QLP four-lane roadway with landscaped median, buffered Class II bike lanes, sidewalk with a separated Class I multi-use trail between 7th Street and 11th Street. QLP from 7th Street to 11th Street would be depressed under the UPRR Niles Subdivision. 11th Street would be extended, and the intersection would be improved.

Figure A-3 shows an overview of Phase 3.
 QLP roadway from 11th Street to 7th Street: Phase 3 would construct QLP improvements from east of the existing BART rail embankment limits to tie into the 7th Street/QLP intersection constructed during Phase 1. This work would include retaining walls and maintenance roads within the Phase 1 limits and wall structures adjacent to the new l Line M Flood Control Channel.
 11th Street extension and traffic signal: Phase 3 would include the extension of 11th Street and the installation of a new traffic signal at the QLP/11th Street intersection.

Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-6 April 2026
Figure A-3. Quarry Lakes Parkway Phase 3 Overview
Attachment A: Description of Quarry Lakes Parkway Phases 1-4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-7 April 2026
 QLP grade separation under the UPRR Niles Subdivision: This would include construction of UPRR tracks, protection of the existing Green Street bridge, and all grade separation and bridge improvements for the UPRR line. This would include construction of interior walls, retaining walls, and a grade-separation structure between QLP and the UPRR line.  UPRR Niles Subdivision railroad shoofly: Phase 3 would construct a temporary shoofly to allow passage and detour around the construction site.
 Pump station and drainage facilities: This phase would include construction of drainage improvements north of the UPRR Niles Subdivision bridge that would be connected to a new pump station (Pump Station #1) near the QLP/11th Street intersection. The pump station would be activated to pump drainage from a 24-inch force main and connect to a 36-inch RCP under gravity flow to a second new pump station (Pump Station #2) constructed during Phase 2. Pump Station #1 would be designed for a 50-year storm event.

Phase 4: Alvarado-Niles Road to 11th Street
Phase 4 would construct a new QLP four-lane roadway with landscaped median, buffered Class II bike lanes, sidewalk with a separated Class I multi-use trail between Alvarado-Niles Road and 11th Street. In Phase 4, the QLP roadway would be depressed under BART and UPRR Oakland Subdivision tracks. Intersection improvements would be added where QLP conforms with Alvarado-Niles Road and at Monterra Terrace/Osprey Drive/Alvarado-Niles Road. Figure A-3 shows an overview of Phase 4.
 QLP roadway from Alvarado-Niles Road to 11th Street: Phase 4 would construct the remaining QLP improvements to connect Alvarado-Niles Road to the limits of Phase 3 work. This phase would include all remaining retaining wall and maintenance roads within the phasing limits. This would involve conforming to Phase 2 work and constructing the fourth leg of the QLP/Alvarado-Niles Road intersection.  QLP grade separation under BART track and UPRR Oakland Subdivision: Phase 4 would include grade-separation work and the BART bridge. This phase would construct interior walls, retaining walls, and a grade separation between QLP and BART and the UPRR Oakland Subdivision, including a BART track shoofly/bus bridge and a UPRR railroad shoofly.
 Drainage facilities: Phase 4 would construct remaining drainage improvements to connect to the pump station in Phase 3. This involves completing the 60-inch RCP diversion pipe connection between Phase 1 and Phase 2. The diverted flow would outfall into Old Alameda Creek from the new outfall.

Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-8 April 2026
A-2: Further Discussion of New Roadway and Other Infrastructure Improvements for the QLP 1–4 Project
New Roadway
The approximately 0.9 mile of new roadway would extend from Mission Boulevard (SR 238) in the east to the realigned QLD in the west. This new four-lane roadway would comply with Caltrans Complete Street Design Guidelines and the design standards of the City of Union City and would not be designed as a freeway or expressway.

The four-lane roadway would be approximately 132 to 143 feet wide (depending on location) and consist of two vehicle lanes in each direction and a multi-use path (20 feet wide with a 16-foot path and 2-foot shoulders on both sides) along QLP adjacent to but separated from roadway, medians, and landscaping. In most locations, there would be landscaped median between the eastbound and westbound lanes and landscaped shoulders. Access to the future residential development west of the new roadway would be provided from both the new roadway and Osprey Drive.

Quarry Lakes Drive Realignment
QLD currently crosses the new roadway alignment west of Alvarado-Niles Road. The project proposes to realign QLD approximately 500 feet to the southwest to increase the distance between two intersections (QLD/new roadway and Alvarado-Niles Road/new roadway) for better traffic operations and maximize the acreage for the residential development site, east of the new roadway. The segment of old QLD between Osprey Drive and the entrance to Quarry Lakes Regional Recreation Area would be removed. The QLD realignment has been designed to avoid physical impacts on the Peterson Farm, although it would entail removal of some vegetation and accessory structures on the property. The roadway’s edge would be approximately 200 feet southwest of the house.

The realigned QLD would extend north across the nonnative grassland field to an intersection with the new roadway. QLD would terminate at the new roadway and not cross it, creating a two-way intersection (that would later be modified to a three-way intersection in Phase 5).

A new overflow pipeline would extend beneath the south side of the new roadway to the new outfall to Old Alameda Creek.

Railroad Grade Separations
The new roadway alignment would be depressed below (from south to north) the existing BART tracks, UPRR Oakland Subdivision track, Green Street bridge, and UPRR Niles Subdivision track, resulting in three new grade-separation structures. The existing Green Street bridge is just south of the UPRR Niles Subdivision tracks, and the proposed roadway Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-9 April 2026
alignment would extend below this existing grade-separation structure. At the point of crossing under the rail tracks and Green Street, the roadway would be between 20 and 26 feet below ground.

For the grade-separation structures, the roadway grade would be lowered from the north side of Alvarado-Niles Road to the south side of 7th Street and would provide a minimum vertical clearance of 16 feet 6 inches below all grade-separation structures. These gradeseparation structures would be supported on pile foundations. The BART grade-separation structures would be similar.

To facilitate construction of the grade separations, the railroad and BART tracks would be shifted onto a temporary alignment called a shoofly. The shoofly would be constructed adjacent to the existing tracks within the existing BART and UPRR right-of-way and would have minimal impact on and disruption to train operations. The minimum distance from the centerline of the shoofly track to an existing residential soundwall would be 10 feet.

Modifications to 7th Street
The northernmost 500 feet of the new roadway alignment would replace a short stretch of the existing 7th Street alignment, which currently curves toward the northwest and provides access to the Corp Yard and nearby residential development. Chesapeake Drive currently intersects this curved portion of 7th Street, with a culvert (Chesapeake Culvert) crossing Detention Basin 2C and the Line M Flood Control Channel. The project proposes to replace this curved alignment of 7th Street with a straight alignment and to joint Chesapeake Drive, resulting in a new signalized QLP/7th Street/Chesapeake Drive intersection.

The new 7th Street alignment would encroach on the parking lot and CNG refueling island at the existing Corp Yard located off 7th Street. This would result in the loss of 15 parking stalls in the parking lot, and a loss of existing on-street parking on 7th Street.

Between 7th Street and Mission Boulevard (SR 238), the new roadway alignment would require a minor right-of-way extension into the southern fringe of Drigon Park, a public dog park owned and operated by the Union City Community & Recreation Services Department.

The project would acquire approximately 23,000 square feet from Drigon Park and would remove some vegetation at the edge of the park. However, none of the physical features inside the park, including the existing fence and surrounding pathway, would be modified.

New Basin and Basin 2C
Between Alvarado-Niles Road and Mission Boulevard (SR 238), the project alignment would extend across two existing stormwater detention basins, referred to as New Basin and Basin 2C.

Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-10 April 2026
New Basin provides detention of stormwater runoff from Pacific Pointe subdivision (Tract 7405), an existing residential subdivision between the UPRR Niles Subdivision track and UPRR Oakland Subdivision track, east of the proposed alignment. When necessary, water that collects in New Basin can be pumped to the Line M Flood Control Channel, an adjacent stormwater conveyance channel, via a pump station on its northern edge and accessible from the Green Street bridge. The San Francisco Bay Regional Water Quality Control Board determined that New Basin is not a water of the state on August 4, 2025.

Basin 2C is an existing wetland mitigation site that also provides stormwater detention storage of overbank flow from the Line M Flood Control Channel. Basin 2C lacks a defined outlet; water is removed through either evaporation or infiltration into the underlying soil.

Both basins would be eliminated to facilitate construction of the new roadway in this location. The loss of stormwater storage functions currently provided by these basins would be mitigated. Per negotiations between the City of Union City and the Alameda Flood Control and Water Conservation District, it is proposed to mitigate 82 cubic feet per second from the Line M Flood Control Channel and 30 cubic feet per second from the Pacific Pointe residential subdivision (Tract 7405) to Old Alameda Creek (see further description below).

Line M Flood Control Channel and Overflow Pipeline
The Line M Flood Control Channel is an existing engineered, channelized drainage facility that starts in the hills north of the project alignment, continues through Union City in a combination of open channel and pipelines, and discharges into the Alameda Creek Flood Control Channel about 0.5 mile downstream of the project alignment. Because the Line M Flood Control Channel is undersized, the area near Chesapeake Drive experiences overflow conditions during heavy storm events. Some overflow goes to Basin 2C, which also serves as a wetland mitigation site for previously authorized wetland impacts from construction of the residential subdivision to the east.

The new roadway alignment would extend over the Line M Flood Control Channel from 250 feet north of Chesapeake Drive south to the UPRR Niles Subdivision. The project would reconstruct the Line M Flood Control Channel in this area to accommodate the new roadway and provide additional capacity to alleviate downstream flooding. At approximately 250 feet north of Chesapeake Drive, a drainage overflow structure would be installed to convey high flows from the Line M Flood Control Channel (approximately 82 cubic feet per second).

The existing Line M Flood Control Channel between Chesapeake Drive and the UPRR Niles Subdivision just south of the Corp Yard would be filled, and a new channel would be constructed approximately 40 feet northwest into the Corp Yard. Approximately 1,421 linear feet of open channel would be filled. The new surface portion of the Line M Flood Control Channel would be approximately 712 feet long. The underground portion of Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-11 April 2026
Line M Flood Control Channel would consist of two 12-foot by 6-foot box culverts where the channel would extend beneath the new roadway, Corp Yard parking lot, and 7th Street.

The new overflow pipeline would extend beneath the east side of the new roadway to the new outfall to Old Alameda Creek.

Roadway Drainage Improvements
The following roadway drainage improvements would be installed as part of Phases 1 through 4 of the project.

In Phase 1, the project would construct new outfalls to the proposed treatment BMPs to maximize treatment of roadway runoff within the project limits. At locations where new outfalls are proposed into unlined channels or biofiltration areas, rock slope protection at the bottom and side slopes is proposed to minimize the effects of the increased flow velocity. For most of the open channels or biofiltration areas, BMP techniques such as hydraulic mulch (bonded fiber matrix) and fiber rolls are proposed to stabilize the banks while ensuring a natural appearance for the channels.

Phase 1 would use bioretention areas adherent to the criteria listed in the Alameda County Clean Water Program C.3 Stormwater Technical Guidance Handbook. These areas would include biotreatment soil at least 18 inches deep, underlain by a minimum of 12 inches of gravel. The gravel layer would contain a perforated underdrain connected to the storm drain system. Runoff from the roadway would be directed into the bioretention areas using inlets and curb cuts placed along the roads or within parking lots.

Phase 1 would include these drainage improvements:
 Fill of the existing Line M Flood Control Channel and construction of a new Line M Flood Control Channel;
 Construction of bioretention areas and permanent BMPs;  Construction of a new double 12-foot by 6-foot reinforced box culvert;  Construction of a new Line M Overflow Pipeline connecting Old Alameda Creek and the Line M Flood Control Channel; and
 Installation of a storm drain conveyance system connecting a series of drainage inlets and storm drain manholes.

Phase 2 would include one new outfall structure to Old Alameda Creek that would receive both the Line M overflow and water from a new water quality basin. The water quality basin is proposed to treat stormwater runoff from the new roadway and the proposed adjacent new development. Phase 2 would also construct new outfall locations into the proposed water quality basin to maximize treatment of roadway runoff within the project limits. At Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-12 April 2026
locations where new outfalls are proposed, headwalls, flared end sections, and rock slope protection would be installed. BMP techniques such as hydraulic mulch (bonded fiber matrix) and fiber rolls are proposed to minimize the effects of the increased downstream flow velocity. Phase 2 would include these drainage improvements:
 Construction of a water quality basin;
 Construction of a pump station;
 A new outfall structure to Old Alameda Creek;
 Installation of a new Line M Overflow Pipeline section from Alvarado-Niles Road to Old Alameda Creek;
 Installation of a storm drain conveyance system connecting a series of drainage inlets and storm drain manholes; and
 Drainage systems to collect the roadway runoff and drain into the water quality basin before discharging into Old Alameda Creek.

The post-construction stormwater controls and hydromodification management measures for Phase 2 would be achieved using both the water quality basin and Old Alameda Creek.

The basin would treat runoff from the roadway, as well as runoff from the new development. A pump station is proposed to convey runoff into the water quality basin before discharging into Old Alameda Creek.

Phase 3 would include construction of a second pump station to route stormwater to the water quality basin in Phase 2. Phases 3 and 4 would include the following drainage improvements:
 Installation of a storm drain conveyance system connecting a series of drainage inlets and storm drain manholes; and
 Construction of drainage improvements north of the UPRR bridge that would be connected to the proposed pump station.

Silva Farmhouse Demolition
Just southeast of its intersection with Alvarado-Niles Road, the project alignment partially crosses the Silva Farm, which has an existing single-family residence and associated barn.

This property was previously owned by Caltrans and leased to the current tenants. The project entails relocating the tenants and demolishing the house and barn.

Old Alameda Creek Outlet Concrete Weir Wall
Old Alameda Creek is connected to the Alameda Creek Flood Control Channel through three 48-inch-diameter pipes that extend under the channel embankment. These pipes are fitted with automatic drainage gates that were installed in the 1960s to prevent water from the Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-13 April 2026
Alameda Creek Flood Control Channel from backing up into Old Alameda Creek. A 2-foothigh concrete weir wall with a 4-foot opening at its center would be constructed on the existing concrete apron just upstream of the three outlets to help with hydromodification mitigation in Old Alameda Creek.

Utilities
The new roadway segments may include additional utility modifications or installations, such as water, gas, electricity, fiber, and telecommunications facilities if needed or requested by the franchised utility providers. The location and extent of these facilities are currently unknown and would be determined by the franchised utility providers.

Throughout the project alignment, existing storm drains and drainage inlets may be relocated and modified to accommodate roadway widening and intersection modifications.

Covers and lids for existing underground utility facilities would also be adjusted.

Compensatory Mitigation
As mitigation for project’s losses of wetlands and other waters of the state, there would be onsite and offsite compensatory mitigation.

Onsite Mitigation
On site, the new Line M Flood Control Channel would include 712 linear feet at the surface with an area of 0.654 acre. The engineering drawings show the new channel.

Offsite Mitigation
It is proposed to establish (create) and enhance wetland and riparian habitats, and preserve existing habitats, within a designated portion of the nearby Eagle Ridge Preserve East property (mitigation property) in the city of Livermore. The primary objective of the mitigation property is to provide compensatory mitigation for unavoidable impacts through the establishment of new drainage features, seasonal wetlands, and riparian habitat, in addition to enhancement of existing riparian habitat and preservation of existing annual grassland habitat.

Habitat Creation
Drainage features would be established by excavating and grading sinuous, linear channels in formerly upland areas. Excavation and grading would expose the soils to direct precipitation and seasonal stormwater flows occurring from late winter through early spring. Construction of the drainage features in these areas would include compaction of the top layer to reduce infiltration. These drainage features would be constructed to intercept surface runoff flowing across the slopes and would ultimately feed into seasonal wetlands constructed on the mitigation property.

Attachment A: Description of Quarry Lakes Parkway Phases 1–4 Project Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 A-14 April 2026
Riparian habitat would be established by planting native riparian woody vegetation and accompanying herbaceous cover along the top of the bank of existing and newly constructed drainage features. This would be accomplished through active revegetation, including a combination of plant installation and maintenance, irrigation, and weed control.

Within the riparian mitigation areas, oaks, shrubs, and forbs would be revegetated on suitable terraces and slopes within the existing drainages. A mix of oak and shrub species would be revegetated along the top of the bank, where the topography and soils are suitable.

Seasonal wetlands would be established by excavating and grading depressions in formerly upland areas. Excavation and grading would expose the clay soils to rainfall and stormwater flows that typically pond and/or saturate the root zone on a seasonal basis during late winter through early spring. Construction of the wetland features in these areas would include compaction of the clay layer to reduce infiltration. Most of the seasonal wetland features would be established along the banks of Cayetano Creek or would drain directly into the creek.

Habitat Enhancement
The portion of Cayetano Creek that flows south through the northern portion of the mitigation area contains steeply incised banks with sporadic riparian vegetation. These banks would be enhanced and stabilized through installation of native riparian plantings.

These plantings would allow for a more natural erosion and sedimentation regime within the feature.

Habitat Preservation
Annual grassland habitat that occurs throughout the upland portions of the mitigation area would be preserved in its current state. This would include the continued use of cattle grazing to control thatch levels and annual surveys for the introduction of any problematic invasive species.

Schedule
Phase 2 (Gateway Connection) will be the first phase and is anticipated to begin early 2027 and be completed by the end of 2028. Phase 1 (7th Street Connection) will be the second phase and is anticipated to begin late 2027 and be completed by end of 2029. Phase 3 (11th Street Connection/Niles Subdivision Grade Separation) is the third phase and is anticipated to begin in 2030 and be completed by 2032. Phase 4 (BART/Oakland Subdivision Grade Separations) is the final, yet most challenging phase anticipated to begin in 2030 and be completed by 2033.

Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-1 April 2026
Attachment B: QLP Phases 1–4 Project Mitigation Measures The mitigation measures adopted pursuant to the EWC that apply to the QLP Phases 1–4 project are included below, including any relevant changes pursuant to this document and the QLP Phases 1–4 project.

Mitigation Measure AES-1: Provide Screened Fencing around Project Staging Areas during Construction
For all work occurring between Paseo Padre Parkway Old Alameda Creek and AlvaradoNiles Road, ACTA Union City will require their contractors to provide screens on all fencing that surrounds staging areas. Screens must be of a neutral color and made of a material that will prevent glare, as received from views outside the staging areas.

Mitigation Measure AES-2: Prepare and Implement a Landscape Plan along the Project Alignment
ACTA Union City will prepare and implement a landscape plan that includes landscaping in the median of the existing and new roadway and along the outside of the new roadway. This will include native, drought-tolerant trees and shrubs.

The project landscape plan will include a vegetated buffer extending from the outside of the soundwalls planted with small trees, shrubs, or vines to screen the walls from outside views. The buffer also may include berms or other minimal landform modifications to soften the landscape and provide visual relief from the new roadway.

Slopes will be graded to appear as natural as possible.

Final design of the landscape plan will be developed in consultation with the planning departments of the City of Fremont Landscape Division and the Union City Planning Department, to enable the incorporation of specific local landscaping or gateway requirements, and with Alameda County Water District (ACWD) to determine appropriate irrigation facilities. These agencies will have the opportunity to review and revise the plan.

Mitigation Measure AES-6: Install Low-Standing Light Standards with Directional Shields Downward along the New Roadway
The light standards used along the new roadway segment will be low-standing with shields directing the light downward. The lights will be the lowest height practicable where new lights are introduced adjacent to residences and where residences are not shielded from direct lighting by soundwalls or landscaping.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-2 April 2026
Mitigation Measure AES-7: Minimize Fugitive Light from Portable Sources In order to minimize fugitive light impacts on residents located along the existing and temporary BART alignment, portable construction lighting will use color-corrected halide lights. At a minimum, construction-related light and glare will be minimized to the maximum extent feasible, given safety considerations. Portable lights will be operated at the lowest allowable height. All lights will be screened and directed downward toward work activities and away from residences adjacent to the project alignment. The number of nighttime lights used will be minimized to the greatest extent possible.

Mitigation Measure AIR-1: Employ Measures to Reduce Criteria Pollutant Emissions during Construction
Construction activities are subject to Caltrans requirements found in the Caltrans document, Standard Specifications: For Construction of Local Streets and Roads (California Department of Transportation 2002). ACTA Union City will follow Caltrans Standard Specification 7-1.01F, Standard Specification 10, and Standard Specification 18, which address the requirements of the local air pollution control district (BAAQMD) and dust control and dust palliative application, respectively. Standard Specification 7-1.01F stipulates that construction activities must comply with all rules, regulations, ordinances, and statutes of the local air pollution control district, while Standard Specification 10 addresses dust control requirements. In addition, BAAQMD requires the implementation of all feasible, effective, and comprehensive control measures to reduce PM10 emissions from construction activities. Therefore, this mitigation includes the following control measures.
 Install wheel washers for all exiting trucks, or wash off the tires or tracks of all trucks and equipment leaving the site.
 Install windbreaks or plant trees or vegetative wind breaks at windward side(s) of construction areas.
 Suspend excavation and grading activity when winds (instantaneous gusts) exceed 25 miles per hour.
 Limit the area subject to excavation, grading, and other construction activity at any one time.
 Hydroseed or apply (nontoxic) soil stabilizers to inactive construction areas (i.e., previously graded areas inactive for 10 days or more).
 Enclose, cover, water twice daily, or apply (nontoxic) soil binders to exposed stockpiles (e.g., dirt and sand).
 Limit traffic speeds on unpaved roads to 15 miles per hour.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-3 April 2026
 Install sandbags or other erosion control measures to prevent silt runoff to public roadways.
 Replant vegetation in disturbed areas as quickly as possible.  Water all active construction areas at least twice daily.  Cover all trucks hauling soil, sand, and other loose materials or require all trucks to maintain at least 2 feet of freeboard.
 Pave, apply water three times daily, or apply (nontoxic) soil stabilizers on all unpaved access roads, parking areas, and staging areas at construction sites.  Sweep daily (with water sweepers) all paved access roads, parking areas, and staging areas at construction sites.
 Sweep streets daily (with water sweepers) if visible soil material is carried onto adjacent public streets.
 Use alternate fuels, catalyst and filtration technologies, and retrofit existing engines in construction equipment.
 Minimize idling time to 5 minutes when construction equipment is not in use, unless per engine manufacturer’s specifications or for safety reasons more time is required.  Manage operation of heavy-duty equipment to reduce emissions and maintain heavy-duty earthmoving, stationary, and mobile equipment in optimum running conditions.
 Employ construction management techniques such as timing construction to occur outside the ozone season of May through October, or scheduling equipment use to limit unnecessary concurrent operation.
 Use electric equipment when feasible.
 Properly maintain equipment according to manufacturers’ specifications.

Mitigation Measure AIR-2: Employ Measures to Reduce Project-Related Greenhouse Gas Emissions
ACTA Union City will ensure the construction contractor employs the following measures to reduce GHG emissions.
 Use recycled, low-carbon, and otherwise climate-friendly building materials such as salvaged and recycled-content materials for hard surfaces, and non-plant landscaping materials.
 Minimize, reuse, and recycle construction-related waste.  Minimize grading, earth-moving, and other energy-intensive construction practices.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-4 April 2026
 Landscape to preserve natural vegetation and maintain watershed integrity.  Use alternative fuels in construction equipment and require construction equipment to use the best available technology to reduce emissions.  Use energy-efficient low-sodium street lights.

Mitigation Measure BIO-2: Conduct Preconstruction Surveys and, If Necessary, Implement Measures to Protect and Mitigate Effects to Special Status Wildlife Species California Red-Legged Frog, California Tiger Salamander, and Western Pond Turtle California Red-legged Frog (CRLF), California Tiger Salamander (CTS) and Western Pond Turtle
Prior to the start of construction activities, ACTA Union City will retain a qualified biologist to conduct preconstruction surveys for CRLF, CTS, and western pond turtle in all suitable habitats in the study area. Surveys will take place no more than 72 hours prior to the onset of site preparation and construction, and will review evaluate the suitable habitat for individuals and nests. If the species is observed during preconstruction surveys, the biologist will remain on site during initial ground-disturbing activities to monitor individuals and ensure that CRLF, CTS, and western pond turtles are not affected by construction activities. Whenever possible, the biologist will work with construction crews to avoid impacts on individuals. If necessary, individual turtles, CRLF, and CTS will be relocated by a DFG CDFW-approved biologist, in accordance with DFG CDFW specifications.

The buffer zones and fencing will remain in place until the young have left the nest, as determined by a qualified biologist.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-5 April 2026
Compensatory mitigation for permanent and temporary loss of habitat for CRLF and CTS shall be provided at the offsite mitigation area at a ratio of 3:1 for permanent impacts and 1:1 for temporary impacts with approximately 18 acres of upland habitat to be preserved at the site.

If construction is planned to occur at the offsite mitigation site during the nesting season (February 1 through August 31), the mitigation contractor will retain a qualified wildlife biologist to conduct breeding season burrowing owl surveys prior to construction. The survey will be conducted to determine if there is a breeding pair within approximately 500 feet of the construction footprint, unless the biologist determines that a smaller survey buffer around the construction footprint is warranted based on preexisting background disturbance and conditions. Survey visits will be timed in accordance with CDFW’s Staff Report on Burrowing Owl Mitigation, Appendix D, Breeding and Non-Breeding Season Surveys and Reports (California Department of Fish and Game 2012). This will provide the Project team advance notice of nesting owls and allow ample time to discuss appropriate avoidance measures with CDFW.

In addition, take avoidance surveys will be conducted no less than 14 days prior to ground-disturbing activities and a final survey will be conducted within 24 hours prior to ground disturbance in all areas of the environmental footprint supporting burrowing owl habitat. If the biologist identifies the presence of a burrowing owl nest in an area scheduled to be disturbed by construction, a 660-foot (~200-meter) no-activity buffer will be established and maintained around the nest while it is active. Surveys and buffer establishment will be performed by qualified wildlife biologists, will be coordinated with CDFW, and will be subject to CDFW review and oversight. The buffer distance will be determined by the time of the year and level of disturbance as recommended in CDFW’s Staff Report on Burrowing Owl Mitigation (California Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-6 April 2026
Department of Fish and Game 2012) (see table below).

Location Time of Year
Level of Disturbance
Low Medium High
Nesting sites April 1- Aug 15 200 m 500 m 500 m
Nesting sites Aug 16-Oct 15 200 m 200 m 500 m
Nesting sites Oct 16-Mar 31 50 m 100 m
m = meters
Crotch’s Bumblebee (CBB) and Western Bumblebee (WBB)
Prior to each phase of construction, a qualified biologist shall conduct a take avoidance survey for active CBB (roadway project area and offsite mitigation area) and WBB (offsite mitigation area only) colony nesting sites. To maximize detection of active bee colonies, the take avoidance survey shall be conducted during the spring, summer, or fall during appropriate weather (not during cool, overcast, rainy, or windy days). The biologist shall walk the entire area proposed for grading and inspect all ground squirrel burrows for bumble bee activity. If any bumble bees are identified during the survey, they shall be identified to species to the extent feasible.

Mitigation Measure BIO-3: Conduct Site Preparation and Construction Activities between September 1 and January 31 to Avoid the Typical Nesting Period of Migratory Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-7 April 2026
Birds, Raptors, or Bird Species of Special Concern and Implement Preconstruction Surveys and Protective Measures if Necessary
Site preparation and initial ground disturbance that require vegetation removal will occur between September 1 and January 31, outside the nesting period for migratory birds, raptors, or bird species of special concern nesting period (February 1 through August 31). Additionally, any demolition of structures will occur outside of the typical nesting period to avoid loss of birds that nest on structures (e.g., phoebes, swallows). If vegetation removal occurs outside the nesting period, no preconstruction survey will be required.

The potential habitats to be surveyed will be determined by the qualified biologist during the survey. If an active nest is discovered, the biologist will establish a nodisturbance buffer zone around the nest tree (or, for ground-nesting species, the nest itself). This no-disturbance zone will be marked with some visual markers (flagging or fencing) that are easily identified by the construction crew, and will not draw attention to the nesting bird. Buffers will remain in place as long as the nest is active or young remain in the area and are dependent on the adults. No construction activity of any type will be permitted within buffer zones. In general, the minimum buffer zone widths will be 300 feet for white-tailed kite and raptors, and 250 feet for migratory birds. Based on discussion with California Department of Fish and Wildlife (CDFW) DFG, buffer widths may be modified, depending on the proximity of activities to the nest(s) and whether the nest(s) will have a direct line of sight to construction activities, existing disturbance levels at the nest(s), local topography and vegetation, the nature of proposed activities, and the species potentially affected.

Mitigation Measure BIO-7: Prepare and Implement a Wetlands Mitigation Plan that Includes the Creation of New Wetlands, Waters of the United States and State, and Replacement and Enhancement of Willow Riparian Woodland and Scrub to Replace Permanent Loss
A plan for wetlands mitigation adjacent to and including Old Alameda Creek will be Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-8 April 2026
developed by qualified wetland botanists, wildlife biologists, hydrologists, engineers, and restoration ecologists.

The wetlands mitigation plan will evolve throughout the project planning so that a selfsustaining mosaic of vegetation communities will replace those affected through project implementation. Ongoing planning efforts will include further input from ICF Jones & Stokes qualified biologists and restoration planners, and consultation with ACTA Union City as further project details are defined. In order to meet the objectives of the mitigation planning process and establish the proposed wetland mitigation site at Old Alameda Creek, the proposed project will include:
 diverting water from Line M Flood Control Channel to increase flow to Old Alameda Creek;
 creating an enhanced new open channel segment of the Line M Flood Control Channel drainage alignment to extend to the continuous linear aquatic habitat of Old Alameda Creek;
 grading new channel banks and regrading creek banks to create benches for additional waters, wetlands, and vegetation creating and enhancing wetland, channel, and riparian areas; and
 planting native wetland and riparian vegetation.

The wetlands mitigation plan will provide for mitigation in at least the following amounts (these amounts may change as necessary to meet permitting requirements):
 2:1 compensation for permanent loss of wetlands;
 1:1 compensation for permanent loss of channel if mitigation is on site and 2:1 compensation if mitigation is off site;
 1:1 compensation for permanent loss of riparian vegetation; and Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-9 April 2026
 0.1:1 compensation for any temporal loss of wetlands, waters (channel), and riparian vegetation.

A draft wetlands mitigation plan for the wetlands mitigation site is shown in Figure 3.3-

Because the plan is conceptual and will require coordination and approval from the Corps and RWQCB, specific information on the anticipated amount of excavation required to implement the plan is not yet finalized, but, based on the draft wetlands mitigation plan, it is estimated to be 230,000 cubic yards of material. Thus, there would be secondary impacts from implementation of this mitigation, including loss of nonnative grasslands and riparian vegetation and increased air emissions. Constructionrelated impacts have been addressed in this and other sections of the Draft EIR.

However, it is anticipated that compensation for impacts on biological resources is included in this wetlands mitigation plan.

The wetlands mitigation plan includes creation of 6.7 acres of willow riparian woodland and scrub to replace (2:1 compensation) loss of this sensitive habitat (from construction of the new roadway and bicycle/pedestrian trail). An additional 2.3 acres of willow Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-10 April 2026
riparian woodland and scrub would be restored (1:1 compensation) in areas temporarily disturbed by construction activities.

Mitigation Measure BIO-8: Protect Willow Riparian Woodland and Scrub Habitat during Project Construction
ACTA Union City will retain a qualified biologist to survey and flag the limits of construction in areas that support willow riparian woodland and scrub. The construction contractor will be required to protect these areas from encroachment and damage during project construction by installing temporary construction fencing. Fencing will be bright-colored and highly visible. Fencing will be installed under the supervision of a qualified biologist to prevent damage to riparian vegetation during installation. The fencing will protect all potentially affected wetlands and a minimum 20-foot buffer zone. Where appropriate and feasible, the buffer zone will be expanded up to 100 feet.

Fencing will be installed before any site preparation or construction work begins and will remain in place for the duration of construction. Construction personnel will be prohibited from entering fenced areas (the exclusion zone) for the duration of project construction. Essential vehicle operation on existing roads will be permitted, but all other construction activities, vehicle operation, material and equipment storage, and other surface-disturbing activities will be prohibited within the exclusion zone.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-11 April 2026
Mitigation Measure BIO-9: Implement Measures to Avoid or Minimize the Dispersal of Noxious Weeds into Sensitive Riparian Areas during Construction To avoid or minimize the introduction or spread of noxious weeds into sensitive riparian areas, ACTA Union City will incorporate the following measures into the construction BMPs.
 If erosion control is needed along the banks of Old Alameda Creek or the Alameda Creek Flood Control Channel, only certified weed-free erosion-control materials will be used.
 Construction supervisors and managers will be educated about noxious weed identification and the importance of controlling and preventing their spread.  Equipment that enters the construction area adjacent to Old Alameda Creek and the Alameda Creek Flood Control Channel will be cleaned at designated wash stations before entering the project alignment. Equipment traveling between the staging area and the riparian construction area will be cleaned once at the start of the project and only subsequently if the equipment leaves the area and returns.

Mitigation Measure BIO-10: Identify Wetlands and Other Waters Temporarily Affected and Install Protective Fencing during Construction
ACTA Union City will retain a qualified biologist to survey and flag wetlands that could be temporarily affected by project construction. All wetlands will be protected from encroachment and damage during construction by installing temporary construction fencing. Fencing will be bright-colored and highly visible. Fencing will be installed under the supervision of a qualified biologist to prevent damage to wetlands during installation. The fencing will protect all potentially affected wetlands and a minimum 20- foot buffer zone. Where appropriate and feasible, the buffer zone will be expanded up to 100 feet. Fencing will be installed before any site preparation or construction work begins and will remain in place for the duration of construction. Construction personnel will be prohibited from entering fenced areas (the exclusion zone) for the duration of project construction. Essential vehicle operation on existing roads will be permitted, but all other construction activities, vehicle operation, material and equipment storage, and other surface-disturbing activities will be prohibited within the exclusion zone.

Mitigation Measure BIO-11: Prepare an Arborist Report and Develop and Implement a Landscaping Plan that Includes Compensation for Loss of Protected Trees ACTA Union City will retain a qualified arborist to prepare an arborist report detailing the size and health of trees that fall within the project alignment and could be removed by the proposed project. The report will identify trees protected under the City of Fremont Tree Preservation Ordinance and the City of Union City Tree Protection Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-12 April 2026
Ordinance. ACTA Union City will hire a qualified landscape architect to prepare a landscape plan that includes adequate compensation or replacement for the loss of protected trees. The City of Fremont Tree Preservation Ordinance requires a 1:1 replacement ratio with a 24-inch-box-sized replacement tree of a species of the same type and size as the removed tree. The Union City Tree Protection Ordinance requires replacement trees in a 15-gallon container at a ratio to be determined by the City of Union City staff.

The landscaping plan for the project alignment will specifically identify the locations where replacement trees are to be planted. The replacement trees will be located on site to the extent feasible, based on space considerations. The plan will be subject to review and approval by the Cities of Fremont and Union City for areas within their jurisdiction. Newly planted trees will be monitored by ACTA Union City at least once a year for 3 years. Each year, any trees that do not survive will be replaced. Any trees planted as remediation for failed plantings will then be monitored for a period of 3 years in the same manner.

Mitigation Measure BIO-12: Install Temporary Fencing around Remaining Protected Trees
Trees that are identified as “protected trees” in the arborist report and that will remain during project construction will be protected from damage during construction by installing temporary fencing. If possible, fencing will be located immediately outside each tree’s drip line. Fencing will keep construction equipment away from trees and prevent unnecessary damage to or loss of heritage trees in the project alignment. Like newly planted trees, any protected trees that are retained and are located adjacent to construction activities will be monitored by ACTA Union City at least once a year for 3 years. Each year, any trees that do not survive will be replaced. Any trees planted as remediation for failed plantings will then be monitored for a period of 3 years in the same manner.

Mitigation Measure CUL-1: Conduct Earthwork Monitoring by Qualified Archaeologist during Construction and Implement Management Measures if Resources are Discovered
ACTA Union City will retain a qualified consulting archaeologist to monitor grounddisturbing activities in all trenching work for utilities installation. The grading plans for the proposed project will contain a note stating that all grading, excavation, or other ground-disturbing activities will be monitored by the consulting archaeologist. The consulting archaeologist will meet with the grading and/or excavation contractor prior to any grading or excavation to discuss the grading plan and explain the monitoring procedures to be followed if cultural resources are encountered. The consulting Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-13 April 2026
archaeologist will be present on site when initial ground-disturbing activities begin, and will monitor all grading, trenching, or other ground disturbance until the grading and trenching reach sterile sandstone or conglomerate strata (where it is assumed that no buried deposits would be present).

In the event cultural resources are encountered during project earthwork, the consulting archaeologist will be empowered to temporarily redirect, divert, or halt project activity to allow recovery of potentially significant cultural resources. The resource’s significance will be determined by the archaeologist and, if the resource is deemed significant, it will be photographed at the site and mapped, before being collected or otherwise addressed in a manner deemed appropriate by the consulting archaeologist (e.g., resource avoidance, data recovery excavations, and so on). The consulting archaeologist will ensure that all significant cultural resources uncovered on the site are analyzed, collected, catalogued, and curated with the Northwest Information Center of the California Historical Resources Information System or other appropriate scientific institution, as deemed appropriate. At the completion of the project monitoring, the consulting archaeologist will prepare a report of findings, even if negative, and submit the report to ACTA Union City and the Northwest Information Center. If cultural resources are not discovered by grading and excavation monitoring, this mitigation measure is not required.

If human remains are uncovered during project earthwork, work will cease and the Alameda County Coroner will be contacted. If the remains are determined to be Native America in origin, the County Coroner will notify NAHC, which will determine and notify the most likely descendent, and coordinate the appropriate management of the remains. If human remains are not discovered by grading and excavation monitoring, this mitigation measure is not required.

Mitigation Measure HAZ-1: Train Construction Workers to Identify Potentially Contaminated Materials and, if Found, Stop Work and Implement Hazardous Materials Investigations and Remediation
Prior to the onset of construction, all construction workers will be trained in the identification of potentially contaminated soil and water, including information on the characteristics of potential contamination, such as discolored soil, oils or sheens on water, and unusual odors. In the event that hazardous materials are encountered during construction, all construction activities in the area of the discovery will stop, and ACTA Union City will conduct hazardous materials investigations to identify the nature and extent of contamination and evaluate potential impacts on project construction. If necessary, ACTA Union City will implement remediation measures consistent with all applicable local, state, and federal codes and regulations. Construction will not resume until remediation is complete. If waste disposal is necessary, ACTA Union City will ensure Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-14 April 2026
that all hazardous materials removed during construction are handled and disposed of by a licensed waste disposal contractor and transported by a licensed hauler to an appropriately licensed and permitted disposal or recycling facility, in accordance with local, state, and federal requirements.

Mitigation Measure HAZ-2: Implement Recommendations in the Phase I Environmental Site Assessment to Prepare a Phase II Environmental Site Assessment, a Health and Safety Plan, and a Soil and Groundwater Management Plan, and to Properly Abandon any Agricultural Wells
Environmental Site Assessment (Fugro West 2008), including preparation of a Phase II Environmental Site Assessment. As required for any specific Phase II ESA conducted in ACWD jurisdiction, the scope of work will be submitted to ACWD and other jurisdictional entities for their review and comment prior to implementation. The Phase II Environmental Site Assessment will be conducted by qualified professionals and will conform to all relevant regulations. For any soil and groundwater assessment requiring a Drilling Permit from ACWD pursuant to this Phase II Environmental Site Assessment or subsequent review, a work plan for chemical investigation will be submitted to ACWD for their approval.

As required by Cal-OSHA standards, a Health and Safety Plan will be prepared prior to the onset of construction activities. The plan will address all activities proposed through implementation of the project. The project-specific Health and Safety Plan will be developed under the guidance of a health and safety professional or certified industrial hygienist before any investigation, cleanup, or construction activities begin in the area.

Workers who could directly contact soil, vapors, or groundwater containing hazardous levels of constituents will perform all activities in accordance with the Health and Safety Plan. The plan will include:
 a description of all planned construction activities;  a list of known contaminants that may be present, including the media that may be affected (e.g., soil, groundwater, soil-vapor) and the highest known concentrations;  the identification of potential physical, mechanical, electrical, and biological hazards that may be encountered;
 the identification of special procedures or precautions that need to be employed (e.g., confine space entry, ambient air monitoring, dust suppression, and so on);  the determination of the level of and list of required personal protective equipment;  the development of contingency measures and decontamination procedures; Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-15 April 2026
 listed emergency contact information, including directions to the nearest hospital; and
 provisions for daily tailgate meetings.

Based on the results of the Phase II Environmental Site Assessment performed for the proposed project alignment, a Soil and Groundwater Management Plan will be prepared to address potential impacts that may occur through implementation of the proposed project. The proposed project would disturb existing shallow soil conditions in the project alignment, and encounter subsurface soil and groundwater where improvements extend below the surface. At a minimum, the Soil and Groundwater Management Plan will establish soil and groundwater mitigation and control specifications for grading and construction activities, including health and safety provisions for monitoring exposure to construction workers, procedures to be undertaken in the event that previously unreported contamination is discovered, and emergency procedures and responsible personnel. The plan will also include procedures for managing soils and groundwater removed from the site to ensure that any excavated soils or dewatered groundwater with contaminants are stored, managed, and disposed of in accordance with applicable regulations. The plan will include:
 the project background and description of proposed actions;  a summary of environmental conditions (e.g., previous investigations, know contaminants, media affected, highest known concentrations, potential exposure pathways, etc.); and
 general soil and groundwater management practices, including:
o site dewatering procedures,
o excess soil handling procedures,
o general construction activities that will occur on or adjacent to the hazardous materials site,
o dust control procedures,
o stormwater runoff procedures,
o soil transportation and disposal procedures (if necessary), o contingency procedures for unexpected conditions (e.g., upon encountering stained or obviously contaminated soil, any USTs, well, associated piping and/or other identifiable environmental conditions posing a potential risk to health, safety, or the environment), and
o reporting procedures.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-16 April 2026
Any wells, agricultural wells, and other improvements that may be encountered throughout the project alignment and wetlands mitigation site during construction activities will be properly abandoned or removed, in coordination with ACWD. In accordance with prior communication with ACWD, abandonment of each agricultural well or improvement will need to be handled on a case-by-case basis in accordance with the California Department of Water Resources guidelines and ACWD specifications. If any hazardous materials, underground storage tanks, soil contamination, or groundwater contamination is encountered during excavation or construction activities, ACWD will be included in the notification and reporting procedures.

Mitigation Measure HAZ-3: Implement Procedures to Reduce Fire Risk during Construction
During construction, all staging areas or areas slated for development using sparkproducing equipment will be cleared of dried vegetation or other materials that could serve as fire fuel. Any construction equipment that normally includes a spark arrester will be equipped with an arrester in good working order. During construction, adequate water will be made available for fire protection.

Mitigation Measure HWQ-1: Comply with National Pollutant Discharge Elimination System Requirements and Develop and Implement a Stormwater Pollution Prevention Plan
ACTA Union City will comply with the requirements of the ACCWP SWQMP, Alameda County’s NPDES General Construction Permit, and Caltrans NPDES permit where applicable before the onset of any construction activities. Compliance and coverage with the SWQMP and NPDES General Construction Permit will require controls of pollutant discharges that use BMPs and technology to reduce erosion and sediments to meet water quality standards. BMPs may consist of a wide variety of measures taken to reduce pollutants in stormwater and other non-point-source runoff. Measures range from source control, such as reduced surface disturbance, to the treatment of polluted runoff, such as detention basins.

A Stormwater Pollution Prevention Plan (SWPPP) will be developed by a qualified engineer or erosion control specialist in accordance with the San Francisco Bay RWQCB requirements for NPDES compliance and implemented prior to the issuance of any grading permit before construction. Additionally, local requirements by the City planning or public works departments will also be incorporated. The SWPPP will be kept on site during construction activity and will be made available upon request to representatives of the San Francisco Bay RWQCB.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-17 April 2026
The SWPPP will include BMPs for the proposed project and may include the following practices.
 Install falsework and netting at bridge construction sites to keep bridge debris and construction materials from falling into the Alameda Creek Flood Control Channel and Old Alameda Creek during construction activities.
 Erosion control measures will be installed adjacent to suitable aquatic habitat to prevent soil from eroding or falling into these areas. Natural and biodegradable erosion control measures (i.e., straw wattles and hay bales) will be used. Plastic monofilament netting (erosion control matting) will not be allowed because salamanders and frogs can become caught in this type of erosion control material.  Contain soil and filter runoff from disturbed areas by berms, vegetated filters, silt fencing, straw wattle, plastic sheeting, catch basins, or other means necessary to prevent the escape of sediment from the disturbed area.  Use a dry detention basin (which is typically dry except after a major rainstorm, when it will temporarily fill with stormwater), designed to decrease runoff during storm events, prevent flooding, and allow for off-peak discharge. Basin features will include maintenance schedules for the periodic removal of sediments, excessive vegetation, and debris that may clog basin inlets and outlets.  Cover, or apply nontoxic soil stabilizers to, inactive construction areas (previously graded areas inactive for 10 days or more) that could contribute sediment to waterways.
 Enclose and cover exposed stockpiles of dirt or other loose, granular construction materials that could contribute sediment to waterways.
 Ensure that no earth or organic material will be deposited or placed where it may be directly carried into a stream, marsh, slough, lagoon, or body of standing water.  Ensure that grass or other vegetative cover will be established on the construction site as soon as possible after disturbance.
 Locate staging areas at least 50 feet away from any drainages.  Prohibit the following types of materials from being rinsed or washed into the streets, shoulder areas, or gutters: concrete; solvents and adhesives; thinners; paints; fuels; sawdust; dirt; gasoline; asphalt and concrete saw slurry; heavily chlorinated water.

ACTA Union City , in coordination with the city planning or public works departments, will select a combination of BMPs to minimize runoff flows and remove contaminants from stormwater discharges. The final selection of BMPs will be subject to approval by the RWQCB. ACTA Union City will verify that a Notice of Intent has been filed with the Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-18 April 2026
State Water Board and that a SWPPP has been developed before allowing construction to begin. ACTA Union City will perform inspections of the construction area, to verify that the BMPs specified in the SWPPP are properly implemented and maintained. ACTA Union City will notify contractors immediately if there is a noncompliance issue and will require compliance. If necessary, ACTA Union City will require that additional BMPs be designed and implemented if those originally constructed do not achieve the identified performance standard.

Mitigation Measure HWQ-2: Clean Paved Areas with Street-Sweeping Equipment To minimize the amount of pollutants entering the storm drain system during construction, project roadways and other paved areas will be cleaned regularly using street-sweeping equipment. Additionally, litter and debris that may accumulate on the streets of the project area will be regularly collected and properly disposed of. These activities will be the responsibility of the applicant or its contractors.

Mitigation Measure HWQ-3: Implement Additional Water Quality Protection Measures to Reduce Sediment in Surface Waters during Construction If construction occurs when flows are present in onsite surface waters (Alameda Creek Flood Control Channel, Old Alameda Creek, Line M Flood Control Channel, and other drainages), the contractor will implement measures to protect surface water quality, including flow diversions, impoundments (e.g., diversion structures), or other methods to avoid the direct exposure of surface water to sediment created as part of construction activity. As a performance standard, the measures will maintain basin plan standards for turbidity. If ambient turbidity is greater than 50 NTUs, then project construction will not exceed 10% over the ambient conditions.

Where the proposed project has potential to result in elevated turbidity, monitoring will be performed at least twice daily at upstream and downstream locations to determine whether the standards outlined above have been met. In the event that they are not being met, the turbidity-generating activities will cease until turbidity is within the identified limits, and construction methods or turbidity control measures will be modified to ensure that turbidity limits continue to be met.

Mitigation Measure HWQ-4: Prepare and Implement a Hazardous Materials Spill Prevention and Control Program during Construction
To ensure compliance with the NPDES General Construction Permit, ACTA Union City will require that project contractors develop and implement a spill prevention and control program to minimize the potential for, and effects from, spills of hazardous, toxic, or petroleum substances during all construction activities. The NPDES General Construction Permit requires the spill prevention and control program. The program will Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-19 April 2026
be completed before any construction activities begin. The program may include the following practices.
 Provision of security for storage areas that contain hazardous materials  Secondary containment for hazardous materials storage  Implementation of preventative measures, specific to hazardous materials that would be used, to prevent spillage of each material
 Provision of containment and cleanup or mop-up supplies at each site  Posted emergency contact information
ACTA Union City will review and approve the spill prevention and control program before the onset of construction activities. ACTA Union City will inspect the construction area routinely to verify that the measures specified in the spill prevention and control program are properly implemented and maintained. ACTA Union City will notify contractors immediately if there is a noncompliance issue and will require compliance.

The federal reportable spill quantity for petroleum products, as defined in 40 CFR 110, is any oil spill that:
 violates applicable water quality standards,
 causes a film or sheen upon or discoloration of the water surface or adjoining shoreline, or
 causes a sludge or emulsion to be deposited beneath the surface of the water or adjoining shorelines.

If a spill is reportable, the contractor will notify the City’s Fire Department and the DTSC, which has a spill response and cleanup ordinances to govern emergency spill response.

A written description of reportable releases must be submitted to the San Francisco Bay RWQCB and the DTSC. This submittal must include a description of the release, including the type of material and an estimate of the amount spilled, the date of the release, an explanation of why the spill occurred, and a description of the steps taken to prevent and control future releases. The releases would be documented on a spill report form.

The contractor will also notify ACWD of reportable spills, and include ACWD in the distribution of spill-related reports prepared for other agencies.

Mitigation Measure HWQ-5: Construct the Tree Wells and Infiltration Basins to Implement the Hydrograph Modification Management Plan for Stormwater Runoff ACTA Union City will coordinate with ACWD, ACCWP, and RWQCB to design and construct the hydrograph modification management plan to detain runoff to match the pre-project runoff conditions for low flows. The plan will include construction of tree Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-20 April 2026
wells and infiltration basins as Integrated Management Practices. Stormwater runoff from the new roadway will be collected and conveyed through the use of underground conduits to infiltration basins. The infiltration basins will be planted with grasses and other vegetation to provide primary treatment by means of infiltration. The tree wells and infiltration basins will be constructed and the vegetation established so they can effectively control flows, trap sediments and uptake nutrients, and decrease the likelihood of poor quality surface runoff reaching Old Alameda Creek. During large storm events when the infiltration basins cannot absorb all the stormwater, the high flows will go into an overflow pipeline extending underground from the basins to outfalls. in The conceptual hydro modification management plan, based on the Water Quality Report prepared by WRECO (2008b) (Appendix M in the EIR), is shown in Figure 3.7-4 in the EIR.

The location of the basins, outfalls, and tree wells shown in the figure are tentative and will be further detailed during the design phase. The basins will be sized according to guidelines set forth in the Alameda Countywide Clean Water Program and are expected to be sized in the range from about 10,000 square feet to 30,000 square feet. They will be located on existing nonnative grassland and will avoid riparian vegetation to the extent possible. If this is not possible, additional mitigation will be required to compensate for these impacts (in addition to what is specified in Mitigation Measure BIO-7). The outfalls from each basin to Old Alameda Creek will include rock slope protection, which will be approximately 72 square feet (6 feet wide, 12 feet long, and 2 to 3 feet deep). The outfalls will be situated above the depth of the 100-year water level.

Mitigation Measure HWQ-6: Incorporate Site-Specific Water Quality Treatment Devices into Site Drainage Plans to Meet Water Quality Standards and Maintain Beneficial Uses
ACTA Union City or their contractors will incorporate stormwater treatment devices into the drainage plan and size the treatment devices according to ACCWP’s permit section Provision C. Up to 50% of this water treatment may occur off site within the swales and/or infiltration basins after they are constructed and landscaping is established. The water treatment devices and detention basins will ensure that water quality standards and beneficial uses of downstream water bodies are met.

These plans will address, but may not be limited to:
 manipulation of the hydroperiod to allow for appropriate plant growth;  other vegetation and sediment management activities, such as periodic vegetation and sediment removal every 5 to 10 years;
 control of water residence time, periodic flushing of the water features, and maintenance of drainage channels and culverts;
Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-21 April 2026
 source control of contaminants reaching the water bodies;  measures to reduce the potential for disease vectors (e.g., mosquitoes and rodents);  measures to ensure that groundwater does not become contaminated;  use of water quality treatment devices such as traction sand traps or media filters; and
 conveying stormwater runoff from the proposed Alameda Creek Flood Control Channel and Old Alameda Creek bridges, by pipeline to an infiltration basin to receive water quality treatment prior to being discharged to Old Alameda Creek.

The measures identified in the drainage plans and measures to protect water quality according to Provision C.3 will conform to the performance standard that water quality in the off-site water features meets the numeric and narrative water quality objectives of the basin plan and that beneficial uses of the downstream water bodies are not compromised.

In addition to water quality BMPs incorporated in the project landscaping described, existing stormwater pipes that carry runoff that have not received primary treatment before being discharged to Line M Flood Control Channel will have an in-line mechanical filtration vault installed before being connected to the new Line M Flood Control Channel diversion pipeline. The vault will contain replaceable filtration media designed to remove sediment and other water quality target contaminants in order to meet Provision C.3 goals. This filtration device is not the primary water quality measure, but will act in series with other BMPs, and the sediment trapping and biological processes in Old Alameda Creek and the Alameda Creek Flood Control Channel.

The 1,100 feet of new channel construction adjacent and connecting to Old Alameda Creek will also increase residence time and vegetation contact time with the project area drainage. This increase in residence time will increase potential for nutrient uptake and sediment removal from Line M Channel diversion flow before they enter Alameda Creek Flood Control Channel. These flows will also expand the contiguous aquatic habitat and riparian corridor of Old Alameda Creek improving its overall water quality improvement capacity.

Mitigation Measure NOI-1: Employ Measures to Reduce Construction Noise to Comply with Applicable Construction Noise Standards
ACTA Union City will require the construction contractor to employ measures to reduce construction noise so that it does not violate applicable construction noise standards.

Measures that can be implemented to reduce construction noise to acceptable levels include, but are not limited to, the following.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-22 April 2026
 For construction occurring within the City of Fremont, limit construction to between 7:00 a.m. to 7:00 p.m. Monday through Friday, and to 9:00 a.m. to 6:00 p.m. on Saturdays and holidays, and prohibit construction on Sunday, as stated in the Fremont Municipal Code. If deviation from these limitations is necessary in order to minimize disruption of traffic on existing roads, coordinate with the Fremont City Manager’s Office to gain official approval for such work, as allowed in the Fremont Municipal Code.
 For construction occurring within the City of Union City, limit all construction activities, including loading and unloading of materials and on-site truck movements, to between 8:00 a.m. and 8:00 p.m., Monday through Friday; 9:00 a.m. to 8:00 p.m.

Saturday; and 10:00 a.m. to 6:00 p.m. Sunday and holidays, as stated in the Union City Municipal Code.
 For construction at the offsite mitigation area within Alameda County, limit all construction activities—including loading and unloading of materials and onsite truck movements—to between 7:00 a.m. and 7:00 p.m., Monday through Friday, 8:00 a.m. to 5:00 p.m. on weekends and holidays, as stated in the Alameda County Noise Element.
 For construction at the offsite mitigation area within Contra Costa County, limit any grading to between 7:30 a.m. and 5:30 p.m., Monday through Friday, as stated in the Title 7 of the Contra Costa County Ordinance Code.
 Use available noise suppression devices and techniques, including:
o equipping all internal combustion engine-driven equipment with mufflers, airinlet silencers, and any other shrouds, shields, or other noise-reducing features that are in good operating condition and appropriate for the equipment;. o using “quiet” models of air compressors and other stationary noise sources where such technology exists;
o using electrically powered equipment instead of pneumatic or internal combustion powered equipment, where feasible;
o using of noise-producing signals, including horns, whistles, alarms, and bells, for safety warning purposes only;
o locating stationary noise-generating equipment, construction parking, and maintenance areas as far as reasonable from sensitive receptors when sensitive receptors adjoin or are near the construction project area; o prohibiting unnecessary idling of internal combustion engines (i.e., in excess of 5 minutes);
Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-23 April 2026
o placing temporary soundwalls or enclosure around stationary noise-generating equipment when located near noise sensitive areas;
o ensuring that project-related public address or music systems are not audible at any adjacent receptor; and
o notifying adjacent residents in advance of construction work.

Mitigation Measure NOI-2: Prepare a Community Awareness Program for Project Construction
ACTA Union City will prepare and maintain a program to enhance community awareness of project construction issues, including noise, vibration, nighttime noise, nighttime lighting, and park or trail closures. Initial information packets will be prepared and mailed to all residences within a 1,000-foot radius of project construction, with updates prepared as necessary to indicate new scheduling or processes. A project liaison will be identified who will be available to respond to community concerns regarding noise, vibration, and light.

Mitigation Measure NOI-3: Conduct Structural Conditions Survey for Areas Where Vibratory Compaction is Proposed
Prior to construction, ACTA Union City will survey all structures within 50 feet of proposed vibratory compacting activities to document the structural composition of structures and note the presence and condition of existing cosmetic or structural cracks or defects that may be sensitive to vibratory compaction. Any sensitive conditions will be reported to the contractor conducting the vibration.

Mitigation Measure NOI-4: Limit Extent of Vibratory Compaction Activity and Vibratory Pile Driving
ACTA Union City will restrict all soil compaction using large, truck-mounted compactors and all vibratory sheet pile driving to areas beyond 50 feet of residential structures or wood-framed buildings, and to areas 20 feet or more from commercial buildings.

Wherever feasible, soil compaction within these limits will be performed with handoperated vibratory rollers.

Mitigation Measure NOI-5: Limit Vibration Levels Received at Structures ACTA Union City will ensure that construction specifications include the following restrictions on vibratory compaction. Vibration at all residential and non-engineered wood frame buildings should be limited to 0.2 in/sec PPV. Vibration at commercial, concrete, and engineered buildings should be limited to 0.3 in/sec PPV. ACTA Union City Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-24 April 2026
will require contractors conducting high-vibration activities to monitor their vibration levels and ensure that the stated levels are not exceeded.

Mitigation Measure NOI-6: Maximize Distance between Shoofly and Residences to Extent Allowed by UPRR
ACTA Union City will maximize the distance between the shoofly and residences to the extent allowed by UPRR.

Mitigation Measure NOI-8: Implement Traffic Noise Reduction Treatments (Soundwalls and Quiet Pavement) at the Affected Residences along the New Roadway between Alvarado-Niles Road and Mission Boulevard (SR 238) ACTA Union City will implement noise reduction measures, including retrofitting existing soundwalls at required locations and a quieter pavement type, along the new roadway segment. These specific measures are described below based on the preliminary traffic noise modeling conducted for the Draft EIR. These measures may be further refined when ACTA Union City performs a detailed noise study, conducted by a qualified acoustical professional, during the final design stage of the proposed project to define reasonable and feasible noise mitigation for the residences near ST-21 (located along the new roadway between Alvarado-Niles Road and Mission Boulevard). The final specifications for noise reduction measures will be determined after the detailed noise study is complete and with approval from the City of Union City, and will be implemented by ACTA Union City.
 Retrofit existing soundwalls to protect existing residential land uses from noise levels that exceed established thresholds. Based on preliminary traffic noise modeling, an increase in the existing soundwall height from 8 feet to 10 feet would be sufficient to maintain noise levels below the exterior noise and land compatibility thresholds. To be effective, soundwalls must be constructed with a solid material with no gaps in the face of the wall or at the base. Openings or gaps between soundwall materials or the ground substantially decrease the effectiveness of the soundwall. Suitable materials for soundwall construction should have a minimum surface weight of 4 pounds per square foot (such as 1-inch- thick wood, masonry block, concrete, or metal).
 Paving the new roadway with “quiet” pavement types such as porous open-grade asphalt concrete with fine aggregate size.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-25 April 2026
Mitigation Measure NOI-9: Conduct Survey for Presence of Air Conditioning at Residences Adjacent to the New Roadway
ACTA Union City will perform a survey of existing residences adjacent to the new roadway alignment to identify residences that currently do not have forced air mechanical ventilation systems. The survey will include residences located in the first row of homes and within 300 feet of the center of the new roadway alignment between Paseo Padre Parkway and Quarry Lakes Drive, and residences located in the first row of homes along the south side of the new roadway segment between Alvarado-Niles Road and Mission Boulevard (SR 238). For locations found to lack air conditioning, and which would thus be unable to maintain closed-window conditions, reasonable and feasible noise mitigation measures will be identified during the final design stage of the project in coordination with and approval from the Cities of Fremont and Union City. Mitigation measures that reduce the proposed project’s significant impacts to less-than-significant levels will be incorporated into the proposed project. These measures may include, but are not limited to, providing forced air ventilation systems to residences, so that windows may be kept closed at the occupant’s discretion to control noise. Where appropriate and needed to meet noise requirements, ACTA Union City will provide funding for double-pane windows.

Mitigation Measure NOI-C1: Contribute to City Funds to Implement Traffic Noise Reduction Treatments
ACTA will contribute to pooled City funds for both Union City and Fremont to implement traffic noise reduction treatments at existing residential areas. With use of this pooled fund, the Cities would perform studies, conducted by qualified acoustical professionals, to define reasonable and feasible noise mitigation for noise-sensitive receptors that are predicted to be exposed to traffic noise increases that exceed the noise significance thresholds. Mitigation measures could include the following.  Construct new or larger soundwalls or berms to protect existing residential land uses where reasonable and feasible.
 Implement alternative noise reduction techniques, such as installing traffic calming measures to slow traffic, coordinating routing and other traffic control measures, or repaving the streets with “quiet” pavement types such as porous open-grade asphalt concrete with fine aggregate size.
 Provide building sound insulation such as sound-rated windows and doors on a caseby-case basis as a method of reducing noise levels in interior spaces of affected residences. This method would be applicable where the construction of soundwalls is not feasible and interior noise levels inside residences are anticipated to exceed 45 dBA Ldn.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-26 April 2026
Mitigation Measure NOI-C2: Use Low Noise Pavement Types on Project Roadways ACTA Union City will pave the project alignment, including both the new roadway and existing roadways being widened, with “quiet” pavement types such as porous opengrade asphalt concrete with fine aggregate size. Specifically, this would include the widening on Decoto Road between Cabrillo Court and Paseo Padre Parkway, the widening of Paseo Padre Parkway between Decoto Road and Isherwood Drive, and the new roadway between Paseo Padre Parkway Old Alameda Creek and Mission Boulevard (Sr 238) except at bridge crossings and in the vicinity of grade separation structures where it is not practicable.

Mitigation Measure PSR-1: Conduct an Investigation of Utility Line Locations and Maintain Utility Services
A detailed study identifying the locations of utilities along the project alignment will be conducted during the design phase of the proposed project. For areas with the potential for adverse impacts on utility services, the following measures will be implemented.  Utility excavation or encroachment permits will be required from the appropriate agencies. These permits include measures to minimize utility disruption. ACTA Union City and its contractors will comply with permit conditions. Such conditions will be included in construction contract specifications.
 Utility locations will be verified through a field survey (potholing) and use of the Underground Service Alert services.
 Detailed specifications will be prepared as part of the design plans to include procedures for the excavation, support, and fill of areas around utility cables and pipelines. All affected utility services will be notified of the project construction plans and schedule. Arrangements will be made with these entities regarding the protection, relocation, or temporary disconnection of services.  Residents and businesses adjacent to the project alignment will be notified of planned utility service disruption 2 to 4 days in advance, in conformance with the Cities of Fremont and Union City and state standards.
 Disconnected cables and lines will be reconnected promptly.  The proposed project will observe all relevant California Department of Public Health standards for utility modification and construction.  The proposed project will observe all relevant ACWD Standard Specifications for Water Main Extension.
 The proposed project will observe the California Department of Health Services (DHS) standards, which require:

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-27 April 2026
o a 10-foot horizontal separation between parallel sewer and water mains, and o a 1-foot vertical separation between perpendicular water and sewer line crossings.

In the event that separation requirements cannot be maintained, the project proponent will obtain a DHS variance through provisions of water encasement or other means deemed suitable by the department.

Mitigation Measure TRA-1: Develop and Implement a Traffic Control Plan for Project Construction
In accordance with the City of Fremont and Union City policies on street closures and traffic diversion for arterial and collector roadways, the construction contractor will prepare a traffic control plan (to be approved by the City engineers) before construction. The traffic control plan will include:
 a street layout showing the location of construction activity and surrounding streets to be used as detour routes, including special signage;  a tentative start date and construction duration period for each phase of construction;
 the name, address, and emergency contact number for those responsible for maintaining the traffic control devices during the course of construction; and  written approval to implement traffic control from other agencies, as needed.

Additionally, the traffic control plan will address the following stipulations required of the proposed project.
 Provide access for emergency vehicles at all times.
 Avoid creating additional delay at intersections currently operating at or approaching congested conditions, either by choosing routes that avoid these locations, or restricting construction-related trips to and from the site to nonpeak times of day.
 Maintain access for driveways and private roads, except for brief periods of construction, in which case property owners will be notified.  Provide adequate off-street parking areas at designated staging areas for construction-related vehicles.
 Maintain pedestrian and bicycle access and circulation during proposed project construction where safe to do so. If construction encroaches on a sidewalk or recreation trail, a safe detour will be provided for pedestrians at the nearest Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-28 April 2026
crosswalk. If construction encroaches on a bike lane, warning signs will be posted that indicate bicycles and vehicles are sharing the roadway.  Provide detours as necessary throughout project construction to maintain safe access to the Quarry Lakes Regional Recreation Area.
 Identify the location of all project-related detours of EBRPD trail facilities through coordination with and approval of EBRPD planning staff, and provide detour signage approved by EBRPD to minimize hazards to trail users.
 Control traffic with flag persons wearing Occupational Safety and Health Administration–approved vests and using a Stop/Slow paddle to warn motorists of construction activity.
 Maintain access to transit services and ensure that public transit vehicles are detoured.
 Post standard construction warning signs in advance of the construction area and at any intersection that provides access to the construction area.  Notify police and fire departments of both Cities of construction locations to ensure that alternative evacuation and emergency routes are designed to maintain response times during construction periods, if necessary during lane closures.  Provide written notification to contractors regarding appropriate routes to and from construction sites, and weight and speed limits for local roads used to access construction sites. Submit a copy of all such written notifications to the City of Fremont and City of Union City planning departments.
 Repair or restore the road rights-of-way to their original condition or better upon completion of the work.

Mitigation Measure TRA-2: Provide Temporary Bus Service during All Interruptions in BART Service
ACTA Union City will coordinate with BART officials to provide bus bridges (buses to shuttle BART passengers) between the Fremont and Union City BART stations. Buses will be scheduled to coincide with the normal BART train schedule, and will be available whenever an interruption in BART service is necessary.

Mitigation Measure TRA-3: Limit Interruption of BART Service to Weekends ACTA Union City will ensure that interruptions of BART service are limited to the weekends. BART ridership is lower on weekends than it is on weekdays, and limiting service interruption to weekends would minimize the number of affected passengers.

Attachment B: QLP Phases 1-4 Project Mitigation Measures Quarry Lakes Parkway Project: Phases 1–4
CEQA Addendum No. 1 B-29 April 2026
ACTA Union City will coordinate with BART officials to determine the schedule for construction work and service interruption.

Mitigation Measure TRA-4: Prepare a Rider Awareness Program Addressing BART Service Interruptions
ACTA Union City, in consultation with BART officials, will prepare a rider awareness program to notify BART passengers of the dates and times of closures and of the availability of bus service during the interruption.

Mitigation Measure TRA-5: Adjust Signal Timing and Signal Coordination at Intersections
ACTA Union City will coordinate with the City of Fremont and Caltrans (for intersections under their respective jurisdiction) to ensure that signal timing and signal coordination are optimized at the following intersections:
 Decoto Road/Fremont Boulevard
 Thornton Avenue/I-880 northbound ramp/Blacow Road
 Thornton Avenue and Fremont Boulevard
 Mission Boulevard and Nursery Avenue

Union City City CouncilApril 28, 2026

Union City City Council
April 28, 2026