Vallejo City Council
March 24, 2026

VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA

INITIAL S TUDY /S UBSEQUENT MITIGATED NEGATIVE DECLARATION NOVEMBER 2025
4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -24 soil, wind speed, and the amount of operating equipment. Larger dust particles would settle near the source, while fine particles would be dispersed over greater distances from the construction site.

Water or other soil stabilizers can be used to control dust, resulting in emission reductions of 50 percent or more. The Air District requires the implementation of the Basic Best Management Practices for Construction-Related Fugitive Dust Emissions (Basic BMPs). With the implementation of these Basic BMPs, fugitive dust emissions from construction activities would not result in adverse air quality impacts.

In addition to dust-related PM10 emissions, heavy trucks and construction equipment powered by gasoline and diesel engines would generate CO, SO2, NOX, ROGs, and some soot particulate (PM2.5 and PM10) in exhaust emissions. If construction activities were to increase traffic congestion in the area, CO and other emissions from traffic would increase slightly while those vehicles are delayed.

These emissions would be temporary and limited to the immediate area surrounding the construction site.

Construction emissions were estimated for the project using CalEEMod, consistent with the Air District’s recommendations. The CalEEMod modeling evaluated construction of the proposed project based on construction initiation in June 2026 and would occur over an approximately 1-year period. Project grading would result in approximately 58,700 cubic yards of soil cut and 59,300 cubic yards for fill, resulting in a total soil import of 600 cubic yards. This analysis utilizes the default construction equipment list and assumes use of Tier 2 construction equipment. All other construction details are not yet known; therefore, default assumptions (e.g., construction worker and truck trips and fleet activities) from CalEEMod were used. Construction-related emissions are presented in Table 4.3.A. CalEEMod output sheets are included in Appendix A.

Table 4.3.A: Project Construction Emissions
Project Construction
Average Daily Pollutant Emissions (pounds per day)

ROG NOX
Exhaust
PM10
Fugitive
Dust PM10
Exhaust
PM2.5
Fugitive
Dust PM2.5
2026 0.3 8.6 0.3 0.4 0.3 0.2
2027 4.0 4.6 0.2 <0.1 0.2 <0.1
Maximum Average Daily Emissions 4.0 8.4 0.3 0.4 0.3 0.2 Air District Thresholds 54.0 54.0 82.0 BMPs 54.0 BMPs
Exceeds Threshold? No No No No No No
Source: Compiled by LSA (April 2025).

Air District = Bay Area Air District
BMPs = best management practices
NOX = nitrogen oxides
PM10 = particulate matter less than 10 microns in diameter PM2.5 = particulate matter less than 2.5 microns in diameter ROGs = reactive organic gases
As shown in Table 4.3.A, construction emissions associated with the project would be less than significant for ROG, NOX, PM2.5, and PM10 exhaust emissions. There are no adopted thresholds for

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VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA
P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) fugitive dust (PM2.5 and PM10) emissions; however, as shown in Table 4.3.A, the Air District requires the implementation of Basic BMPs to ensure that impacts are reduced to a less than significant level with mitigation. In addition to the Air District regulations, the General Plan EIR identified General Plan EIR Mitigation Measure AQ-2b.1, which requires development projects to implement the Air District’s current Basic BMPs. Measures include watering exposed surfaces, covering haul trucks, limiting vehicle speeds on unpaved roads, using wet power sweepers, and suspending work during high winds. Additional requirements involve paving surfaces promptly, washing vehicles before site exit, stabilizing unpaved access roads, and posting contact information for dust complaints. These measures would ensure that short-term impacts associated with the generation of particulate matter and fugitive dust would be reduced to the extent feasible and would ensure that this impact would be less than significant.

With implementation of General Plan EIR Mitigation Measure AQ-2b.1, construction of the proposed project would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is in nonattainment under an applicable federal or State ambient air quality standard. With implementation of General Plan EIR Mitigation Measure AQ-2b.1, no new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR Operational Emissions. Long-term air pollutant emission impacts are those associated with mobile sources (e.g., vehicle trips), energy sources (e.g., natural gas), area sources (e.g., architectural coatings and the use of landscape maintenance equipment), and stationary sources (e.g., backup generator) related to the proposed project.

Mobile source emissions include ROGs and NOX emissions that contribute to the formation of ozone.

Additionally, PM10 emissions result from running exhaust, tire and brake wear, and the entrainment of dust into the atmosphere from vehicles traveling on paved roadways.

Energy source emissions result from activities in buildings for which natural gas is used. The quantity of emissions is the product of usage intensity (i.e., the amount of natural gas) and the emission factor of the fuel source.

Typically, area source emissions consist of direct sources of air emissions located at the project site, including architectural coatings, consumer products, and the use of landscape maintenance equipment. In addition, stationary source emissions would be associated with use of the standby backup generator.

Emissions estimates for operation of the project were calculated using CalEEMod. Model results are shown in Table 4.3.B. Trip generation rates for the project were based on the project’s trip generation estimates as identified in Section 4.17, Transportation and Traffic. Based on the trip generation estimates, the proposed project would generate approximately 481 average daily trips.

In addition, the proposed project would have a standby diesel backup generator. Therefore, this analysis conservatively assumes that there would be a 500-horsepower diesel generator that would run up to 50 hours annually. Where project-specific data were not available, default assumptions (e.g., electricity usage, water usage, and solid waste generation) from CalEEMod were used to estimate project emissions.

VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA

INITIAL S TUDY /S UBSEQUENT MITIGATED NEGATIVE DECLARATION NOVEMBER 2025
4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -26 Table 4.3.B: Project Operation Emissions
ROGs NOX PM10 PM2.5
Pounds Per Day
Mobile Source Emissions 1.9 1.9 3.6 0.9
Area Source Emissions 2.6 <0.1 <0.1 <0.1
Energy Source Emissions <0.1 0.4 <0.1 <0.1
Stationary Source Emissions 0.1 0.3 <0.1 <0.1
Total Emissions 4.7 2.6 3.7 1.0
Air District Thresholds 54.0 54.0 82.0 54.0
Exceed Threshold? No No No No
Tons Per Year
Mobile Source Emissions 0.3 0.4 0.7 0.2
Area Source Emissions 0.5 <0.1 <0.1 <0.1
Energy Source Emissions <0.1 0.1 <0.1 <0.1
Stationary Source Emissions <0.1 0.1 <0.1 <0.1
Total Emissions 0.9 0.5 0.7 0.1
Air District Thresholds 10.0 10.0 15.0 10.0
Exceed Threshold? No No No No
Source: Compiled by LSA (March 2025).

Note: Some values may not add up due to rounding.

Air District = Bay Area Air District
NOX = nitrogen oxides
PM10 = particulate matter less than 10 microns in size
PM2.5 = particulate matter less than 2.5 microns in size ROGs = reactive organic gases
The primary emissions associated with the project are regional in nature, meaning that air pollutants are rapidly dispersed on release or, in the case of vehicle emissions associated with the project, emissions are released in other areas of the Air Basin. The daily and annual emissions associated with project operational trip generation, energy, and area sources are identified in Table 4.3.B for ROGs, NOX, PM10, and PM2.5.

The results shown in Table 4.3.B indicate the project would not exceed the significance criteria for daily or annual ROG, NOX, PM10, or PM2.5 emissions. Therefore, operation of the proposed project would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under applicable federal or State ambient air quality standards.

Impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

Localized CO Impacts. Emissions and ambient concentrations of CO have decreased dramatically in the Bay Area with the introduction of the catalytic converter in 1975. No exceedances of the State or federal CO standards have been recorded at Bay Area monitoring stations since 1991. The Air District’s 2022 CEQA Guidelines include recommended methodologies for quantifying concentrations of localized CO levels for proposed projects. A screening level analysis using guidance from the Air District’s 2022 CEQA Guidelines was performed to determine the impacts of the project. The screening methodology provides a conservative indication of whether the implementation of a proposed project would result in significant CO emissions. According to the Air

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VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA
P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) District’s 2022 CEQA Guidelines, a project would result in a less than significant impact to localized CO concentrations if the following screening criteria are met:
• The project is consistent with an applicable congestion management program established by the county congestion management agency for designated roads or highways and the regional transportation plan and local congestion management agency plans. • Project traffic would not increase traffic volumes at affected intersections to more than 44,000 vehicles per hour (vph).
• The project would not increase traffic volumes at affected intersections to more than 24,000 vph where vertical and/or horizontal mixing is substantially limited (e.g., tunnel, parking garage, bridge underpass, natural or urban street canyon, or below-grade roadway).

Implementation of the proposed project would not conflict with the policies or programs of the Solano County Transportation Authority. As identified in Section 4.7, Transportation and Traffic, the proposed project would generate approximately 35 a.m. vehicle trips during the morning peak hour of travel and 48 p.m. vehicle trips during the evening peak hour of travel. As the project’s contribution to peak-hour traffic volumes at intersections in the vicinity of the project site would be well below 44,000 vph, the proposed project would not result in localized CO concentrations that exceed State or federal standards, and project impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. c. Would the project expose sensitive receptors to substantial pollutant concentrations? (Less than Significant with Mitigation Incorporated, No New Impact) Sensitive receptors are defined as residential uses, schools, daycare centers, nursing homes, and medical centers. Individuals particularly vulnerable to diesel particulate matter (DPM) are children, whose lung tissue is still developing, and the elderly, who may have serious health problems that can be aggravated by exposure to DPM. Exposure from diesel exhaust associated with construction activity contributes to both cancer and chronic non-cancer health risks.

According to the Air District, a project would result in a significant impact if it would individually expose sensitive receptors to TACs, resulting in an increased cancer risk greater than 10 in 1 million, increased non-cancer risk of greater than 1.0 on the Hazard Index (chronic or acute), or an annual average ambient PM2.5 increase greater than 0.3 µg/m.3
The project site is in an urban area in proximity to existing single-family residential uses that could be exposed to diesel emissions exhaust during the construction period. Therefore, a construction HRA, which evaluates construction-period health risk to off-site receptors, was performed for construction of the proposed project. To estimate the potential cancer risk associated with construction activities from equipment exhaust (including DPM), a dispersion model was used to translate an emissions rate from the source location to a concentration at the receptor location of interest (i.e., a nearby residence and worksites). Dispersion modeling varies from a simpler, more conservative screening-level analysis to a more complex and refined detailed analysis.

VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA

INITIAL S TUDY /S UBSEQUENT MITIGATED NEGATIVE DECLARATION NOVEMBER 2025
4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -28 For the purposes of an HRA, emissions are analyzed for acute health impacts, chronic, and carcinogenic health impacts. A multi-pathway assessment was conducted to evaluate the project’s emissions during construction following the modeling techniques recommended in the California Environmental Protection Agency’s (CalEPA) Office of Environmental Health Hazard Assessment (OEHHA) Air Toxic Hot Spots Program Risk Assessment Guidelines. 24 The analysis herein has been
conducted in accordance with the Air District’s requirements for HRAs.

The HRA analysis was conducted using three models: (1) CalEEMod to determine DPM emissions during project construction; (2) the USEPA AERMOD air dispersion model to determine how the TACs would move through the atmosphere; and (3) CARB’s Hotspots Analysis and Reporting Program (HARP2) model to translate the pollutant concentrations from AERMOD into individual health risks at any sensitive receptor locations surrounding the project site.

The OEHHA has determined that long-term exposure to diesel exhaust particulates poses the highest cancer risk of any TAC it has evaluated. Exposure to diesel exhaust can also have immediate health effects. Diesel exhaust can irritate the eyes, nose, throat, and lungs, and it can cause coughs, headaches, lightheadedness, and nausea. In studies with human volunteers, DPM made people with allergies more susceptible to the materials to which they were allergic, such as dust and pollen.

Exposure to DPM also causes inflammation in the lungs, which may aggravate chronic respiratory symptoms and increase the frequency or intensity of asthma attacks. For risk assessment procedures, the OEHHA specifies that the surrogate for whole diesel exhaust is DPM. The HRA analyses used PM10 emissions to represent DPM emissions, consistent with OEHHA guidance.

The conservative nature of this analysis is due primarily to the following factors:
• The CARB-adopted diesel exhaust unit risk factor (URF) of 300 in 1 million per micrograms per cubic meter (μg/m3
) is based on the upper 95th percentile of estimated risk for each of the epidemiological studies used to develop the URF. Therefore, the risk factor is representative of DPM.
• The exposure to DPM is assumed to be constant for the given period analyzed (i.e., 70 years).

However, emissions from DPM are expected to substantially decrease in the future with the implementation of standard regulatory requirements and technological advancement to reduce DPM.

Table 4.3.C, below, identifies the results of the analysis. Model outputs and snapshots of the sources are provided in Appendix B.
24 California Environmental Protection Agency (CalEPA) Office of Environmental Health Hazard Assessment (OEHHA). 2015. Air Toxics Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments. March. Website: https://oehha.ca.gov/air/air-toxics-hot-spots (accessed March 2025).

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VISTA COVE PLANNED DEVELOPMENT P ROJECT

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Table 4.3.C: Unmitigated Inhalation Health Risks from Project Construction to Off-Site Receptors
Carcinogenic
Inhalation Health Risk
in 1 Million
Chronic Inhalation
Hazard Index
Acute Inhalation
Hazard Index
Annual PM2.5
Concentration
(µg/m3)
Residential Receptor MEI 67.99 0.059 0.000 0.29
Worker Receptor MEI 0.46 0.023 0.000 0.11
School Receptor MEI 2.90 0.028 0.000 0.14
Threshold 10.0 1.0 1.0 0.30
Exceed Threshold? Yes No No No
Source: Compiled by LSA (March 2025).
µg/m3 = micrograms per cubic meter
MEI = maximally exposed individual
PM2.5 = particulate matter less than 2.5 microns in size As shown in Table 4.3.C, the maximum cancer risk for the residential receptor maximally exposed individual (MEI) associated with project construction would be 67.99 in 1 million, which would exceed the Air District’s cancer risk of 10 in 1 million and would result in a potentially significant impact without mitigation. The school receptor MEI and worker receptor MEI risk would be lower at

2.90 in 1 million and 0.46 in 1 million, respectively, which would also not exceed the Air District’s cancer risk threshold. The chronic hazard index would be 0.059 for the residential receptor MEI,

0.028 for the school receptor MEI, and 0.023 for the worker receptor MEI, which are below the threshold of 1. In addition, the acute hazard index would be nominal (0), which would also not exceed the threshold of 1. The results of the analysis indicate that the PM2.5 concentration would be

0.29 µg/m3 for the residential receptor MEI, 0.14 µg/m3 for the school receptor MEI, and 0.11 µg/m3 for the worker receptor MEI, which also would not exceed the Air District’s significance threshold of

0.3 µg/m3
. Therefore, implementation of Project Specific Mitigation Measure AIR-1, which would require the use of cleaner construction equipment, would be necessary to reduce substantial pollutant concentrations during project construction.

Project Specific Mitigation Measure AIR-1 Tier 4 Final Emissions Standards. During construction of the proposed project, the project
contractor shall ensure all off-road, diesel-powered
construction equipment of 50 horsepower or more
used for the project construction meets, at a
minimum, the California Air Resources Board Tier 4
Final emissions standards or the equivalent.

Table 4.3.D identifies the results of the analysis with implementation of Project Specific Mitigation Measure AIR-1.

VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA

INITIAL S TUDY /S UBSEQUENT MITIGATED NEGATIVE DECLARATION NOVEMBER 2025
4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -30 Table 4.3.D: Mitigated Inhalation Health Risks from Project Construction to Off-Site Receptors
Carcinogenic
Inhalation Health
Risk in 1 Million
Chronic
Inhalation
Hazard Index
Acute
Inhalation
Hazard Index
Annual PM2.5
Concentration
(µg/m3)
Residential Receptor MEI 4.52 0.004 0.000 0.02
Worker Receptor MEI 0.03 0.002 0.000 0.01
School Receptor MEI 0.19 0.002 0.000 0.00
Threshold 10.0 1.0 1.0 0.30
Exceed Threshold? No No No Exceed Threshold?
Source: Compiled by LSA (March 2025).
µg/m3 = micrograms per cubic meter
MEI = maximally exposed individual
PM2.5 = particulate matter less than 2.5 microns in size As shown in Table 4.3.D, the mitigated cancer risk at the residential receptor MEI would be 4.52 in 1 million, which would not exceed the Air District’s cancer risk threshold of 10 in 1 million.

Therefore, with implementation of Project Specific Mitigation Measure AIR-1, construction of the proposed project would not exceed Air District thresholds and would not expose nearby sensitive receptors to substantial pollutant concentrations.

Once the proposed project is constructed, it would not be a source of substantial emissions, and consequently, implementation of the proposed project would not result in new sources of TACs.

Therefore, the project would not expose sensitive receptors to substantial levels of TACs, and this impact would be less than significant with mitigation. With implementation of Project Specific Mitigation Measure AIR-1, no new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
d. Would the project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people? (Less than Significant Impact, No New Impact) During project construction, some odors may be present due to diesel exhaust. However, these odors would be temporary and limited to the construction period. Once operational, the proposed project would not include any activities or operations that would generate objectionable odors and once operational, the project would not be a source of odors. Therefore, the proposed project would not result in other emissions (such as those leading to odors) adversely affecting a substantial number of people. This impact would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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4.4 BIOLOGICAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S.

Fish and Wildlife Service?
b. Have a substantial adverse effect on any riparian
habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or U.S. Fish
and Wildlife Service?
c. Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to,
marsh, vernal pool, coastal, etc.) through direct
removal, filling, hydrological interruption, or other
means?
d. Interfere substantially with the movement of any
native resident or migratory fish or wildlife species or with established native resident or migratory wildlife
corridors, or impede the use of native wildlife nursery sites?
e. Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?
f. Conflict with the provisions of an adopted Habitat
Conservation Plan, Natural Community Conservation
Plan, or other approved local, regional, or state habitat conservation plan?

4.4.1 Prior Environmental Analysis
Chapter 4.3 of the General Plan EIR analyzed impacts to biological resources associated with build out of the General Plan, and determined that without the implementation of adequate identification, controls and restrictions, and requirements for compensatory mitigation, build out of the General Plan could have a substantial adverse effect on special-status species, sensitive natural communities, protected wetlands, and native resident or migratory wildlife corridors and native wildlife nursery sites. The General Plan EIR prescribed Mitigation Measure BIO-1, which requires a biological assessment for new development proposed on sites that are determined to have some potential to contain sensitive biological and wetland resources, CEQA environmental review, the avoidance of potential impacts on jurisdictional wetlands and other waters, the protection of the nests of raptors and other birds, and the protection of the remaining woodlands and native tree resources (including the replacement of removed trees). With implementation of General Plan EIR Mitigation Measure BIO-1, impacts on biological resources were considered reduced to less than

VISTA COVE PLANNED DEVELOPMENT P ROJECT

V ALLEJO, C ALIFORNIA

INITIAL S TUDY /S UBSEQUENT MITIGATED NEGATIVE DECLARATION NOVEMBER 2025
4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -32 significant. Additionally, the General Plan includes the following goals, policies, and actions related to biological resources which would be applicable to the proposed project:
• Policy NBE-1.1: Natural Resources. Protect and enhance hillsides, waterways, wetlands, occurrences of special-status species and sensitive natural communities, and aquatic and important wildlife habitat through land use decisions that avoid and mitigate potential environmental impacts on these resources to the extent feasible. ○ Action NBE-1.1B: Continue to participate in the implementation of regional habitat conservation and restoration programs, including the Solano Multispecies Habitat Conservation Plan and Natural Community Conservation Plan, and wetland restoration occurring in the Napa/Sonoma Marshes.
• Policy NBE-1.2: Sensitive Resources. Ensure that adverse impacts on sensitive biological resources, including special-status species, sensitive natural communities, and wetlands are avoided and mitigated to the greatest extent feasible as development takes place. ○ Action NBE-1.2D: Protect the remaining woodlands and native tree resources, and require replacement plantings where native trees must be removed. ○ Action NBE-1.3B: Work with landowners to facilitate assembly and retention of parcels of sufficient size to preserve valuable tidal marshes, seasonal marshes, managed wetlands and contiguous grassland areas for the protection of aquatic and wildlife habitat. • Policy NBE-1.6: Open Space. Conserve and enhance natural open space areas in and adjacent to Vallejo and its waterfront.
• Policy NBE-1.7: Green Infrastructure. Encourage the installation of green infrastructure, including tools such as permeable pavement, rain gardens, constructed wetlands, grassy swales, rain barrels and cisterns, and green roofs, to treat stormwater, attenuate floods, increase groundwater recharge, and reduce urban heat islands.

4.4.2 Background
This section summarizes the literature review, records search, and field investigation that were completed to inform the existing conditions on the site related to biological resources and describes the existing biological resources environment of the project site and its vicinity including site soils and topography, climate, hydrology, land use, and plant and animal species and communities that have potential to occur. The analysis of potential impacts to biological resources is based on the sitespecific Biological Resources Impact Analysis25 and Arborist Report26 completed for the proposed project by WRA. Additionally, peer reviews of the Biological Resources Technical Report27 and 25 WRA, Inc. 2024. Biological Resources Technical Report Vista Cove Project, Vallejo, Solano County, California. February. 26 WRA, Inc. 2023. Sancerra Vista Cove Development Project – Arborist Tree Survey and Report. February 22. 27 LSA Associates, Inc. (LSA). 2025. Third-Party Review of Biological Resources Report for the Vista Cove Project in Vallejo, California. March 17.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Arborist Report28 were completed by LSA to determine whether the reports comply with CEQA and conform to accepted methodologies and procedures (industry standards). Peer reviews included one round of review and the submission of findings to the City detailing areas requiring modification. All reports related to Biological Resources are included in Appendix C of this Initial Study.

4.4.2.1 Literature Review and Records Search
Prior to conducting the field investigation for the biological resources impact analysis, a literature review and records search were conducted to assess the potential for sensitive biological communities and special-status species to occur on or within the vicinity of the project site, including the following:
• Soil Survey of Solano County, California29
• Benicia 7.5-minute United States Geological Survey (USGS) quadrangle • Contemporary aerial photographs30
• Nationwide Environmental Title Research
• National Wetlands Inventory (NWI)
• California Aquatic Resources Inventory
• California Natural Diversity Database (CNDDB)
• California Native Plant Society (CNPS) Inventory
• Consortium of California Herbaria
• United States Fish and Wildlife Service (USFWS) List of Federal Endangered and Threatened Species
• eBird Online Database
• California Bird Species of Special Concern in California31 • California Amphibian and Reptile Species of Special Concern32 28 LSA Associates, Inc. (LSA). 2025. Third-Party Review of Arborist Report for the Vista Cove Project in Vallejo, California. March 17. 29 United States Department of Agriculture Natural Resources Conservation Service. 1969. Soil Survey of Solano County, California. 30 Google Earth. 2024. Aerial Imagery 1985-2002 (most recently accessed February 2024). 31 Shuford, W.D., and T. Gardali, eds. 2008. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California.

Western Field Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento. 32 Thomson, R.C., A.N. Wright, and H.B. Shaffer. 2016. California amphibian and reptile species of special concern. Co-published by the California Department of Fish and Wildlife and University of California Press, Oakland, California.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -34 • A Field Guide to Western Reptiles and Amphibians33
• A Manual of California Vegetation, Online Edition
• Preliminary Descriptions of the Terrestrial Natural Communities34 • California Natural Community List
• Database searches (i.e., CNDDB, CNPS) for special-status species focused on the Cuttings Wharf, Cordelia, Fairfield South, Mare Island, Benicia, Vine Hill, Richmond, Briones Valley, and Walnut Creek USGS 7.5-minute quadrangles.

4.4.2.2 Habitat Assessment/Field Investigation
Following the literature review for the Biological Resources Impact Analysis, WRA biologists conducted field assessments on February 28 and July 14, 2022 to document the following: (1) land cover types (e.g., terrestrial communities, aquatic resources), (2) existing conditions and to determine if suitable habitat is provided for any special-status plant or wildlife species, (3) the presence of aquatic natural communities (e.g., wetlands), and (4) if special-status species are present.

The Arborist Report was prepared based on an arborist survey performed on October 12, 2022, which was conducted by WRA’s International Society of Arboriculture (ISA)-Certified Arborist and Tree Risk Assessment Qualified arborist for the purpose of documenting all trees with a diameter at breast height (DBH) greater than 6 inches within the project site outside of the riparian area.

Relevant information was recorded for each surveyed tree, including: tree number, species, trunk DBH, max drip, condition rating, health rating, structure rating, health, and comments. Surveyed trees were recorded using sub-meter accuracy global positioning system (GPS) devices and trees were tagged with aluminum tree tags with a unique identifying number.

4.4.2.3 Site Soils and Topography
Undulating hills with flat areas, with elevations ranging from approximately 97 to 180 feet above sea level, characterize the project site topography. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Web Soil Survey, the project site is underlain by Dibble-Los Osos clay loams, including three soil mapping units: 2 to 9 percent slopes, 9 to 30 percent slopes, and 30 to 50 percent slopes. The Dibble-Los Osos Clay Loam series consists of moderately deep, well drained soils that formed in material weathered from shale, sandstone and semi consolidated densic material. The soil pH ranges from 5.6 to 7.3, resulting in neutral to acidic soils. Dibble soils are on foothills and fan remnants and have slopes of 2 to 75 percent. These soils are not considered hydric.
33 Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians, Third edition. Houghton Mifflin Company, Boston, MA and New York, NY. 34 Holland, R.F. 1986. Preliminary descriptions of the terrestrial natural communities of California. State of California, The Resources Agency, Department of Fish and Game, Sacramento, CA.

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4.4.2.4 Climate
The average monthly maximum temperature in the area is 68.6 degrees Fahrenheit, while the average monthly minimum temperature is 49.3 degrees Fahrenheit. Predominantly, precipitation falls as rainfall between November and March with an annual average precipitation of 17.7 inches.

4.4.2.5 Hydrology
The regional watershed for the project site is San Francisco Bay (Hydrologic Unit Code [HUC] 6:
180500) between the San Pablo Bay (HUC 8:18050002) and Suisun Bay (HUC 8: 18050001) watersheds. The project site is located in the central portions of the Suisun/San Pablo Bay watersheds. Two streams are mapped on the project site according to the National Wetland Inventory (NWI). However, there are no mapped blue line streams35 on the project site according to the Benicia 7.5 minute quadrangle.

The stream features shown in the NWI start at the edge of the residential properties to the west of the project site and run east towards the marsh located in the Benicia State Recreation Area, and eventually, the Southampton Bay within the Carquinez Strait (0.9 mile south of the project site). The northern aquatic feature is a topographical low intermittent stream36 that appears to have started conveying water and supporting riparian vegetation after the adjacent housing development was constructed in the 1980s and the stormwater basin directed runoff to this area. The southern aquatic feature within the project site is a historical drainage that coveys water from the hillside to the adjacent marsh southeast of the project site; however, additional stormwater and other runoff is directed into this feature. Both aquatic features receive runoff from the neighboring properties via culverts. Although NWI classifies the southern feature as a stream, due to wetland vegetation growing in the channel, it was classified as a freshwater marsh, which is considered a sensitive land cover type.

4.4.2.6 Land Use
The majority of the project site is dominated by non-native annual grassland. One intermittent stream, connected to a seasonal wetland, and one linear freshwater marsh are located on the project site. The area was used for agriculture as early as 1948 and was left as open space following the construction of the neighboring community to the west of the project site, in the early 1980s.

4.4.2.7 Vegetation Communities and Other Land Cover
The project site primarily includes the following vegetation communities: riparian, toyon chaparral, coyote brush scrub, poison oak scrub, artichoke thistle field, and non-native grassland. Additionally, 35 A blue-line stream is a body of concentrated flowing water in a natural low are or natural channel on the land surface and may be any creek, stream or other flowing water feature, perennial or ephemeral, indicated on USGS quadrangle maps, with the exception of man-made watercourses. 36 A topographical low is a low-lying area on the Earth’s surface, typically represented by contour lines forming concentric circles on a topographic map which indicate that the elevation decreases towards the center of the depression.

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Toyon Chaparral. Toyon chaparral is mapped in the central/southern portion of the project site on the steep slope above and adjacent to the freshwater marsh. It is characterized by open to dense shrub canopy dominated by toyon (Heteromeles arbutifolia) with occasional coyote brush (Baccharis pilularis) and poison oak (Toxicodendron diversilobum). This land cover type meets the membership rules for holly leaf cherry – toyon – greenbark ceonothus chaparral (Prunus ilicifolia –Heteromeles arbutifolia – Ceanothus spinosus Shrubland Alliance). Interstitial areas are dominated by non-native annual grasses such as wild oat (Avena sp.) and purple false brome (Brachypodium distachyon).

Occasional small coast live oak trees are present at low cover. Although the general holly leaf cherry – toyon – greenbark ceonothus chaparral Alliance is not considered sensitive by the California Department of Fish and Wildlife (CDFW), the toyon – holly leaf cherry species association within that alliance is considered sensitive.

Coyote Brush Scrub. A small patch of coyote brush scrub was mapped in the northern portion of the project site. It is an open stand of shrubs dominated by coyote brush and meets the membership rules for the coyote brush scrub (Baccharis pilularis Shrubland Alliance). The interstitial areas are dominated by wild oat, and no trees are present. Coyote brush scrub is not considered sensitive.

Poison Oak Scrub. Poison oak scrub was mapped near the top of the steep ridge in the southern portion of the project site. It is characterized by an open shrub canopy dominated by poison oak, with occasional toyon and coyote brush present. It meets the membership rules for the poison oak scrub (Toxicodendron diversilobum Shrubland Alliance). The interstitial areas are dominated by nonnative herbs such as fennel (Foeniculum vulgare), wild oat, and purple false brome. Poison oak scrub is not considered sensitive.

Artichoke Thistle Field. The artichoke thistle field was mapped on the steep slope in the southernmost portion of the project site. The vegetation is herbaceous and dominated by artichoke thistle (Cynara cardunculus ssp. flavescens), with other non-native herbs between artichoke thistle plants, including wild oat, purple false brome, black mustard (Brassica nigra), Italian thistle (Carduus pycnocephalus ssp. pycnocephalus), and fennel. Trees and shrubs were typically absent. This land cover type meets the membership rules for the upland mustards or star-thistle fields (Brassica nigra – Centaurea [solstitalis, melitensis] Herbaceous Semi-natural Alliance). Artichoke thistle field is not considered sensitive.

Non-native Grassland. Non-native grassland is the most common land cover type within the project site, occurring on all slopes and aspects. Portions of this land cover type are periodically mowed, and in the far northern portion of the project site, a two-track dirt vehicle path is present.

Vegetation is herbaceous and is typically characterized by dense wild oat (Avena spp.), with occasional shrubs, trees, and other herbs present at low cover. It intergrades with the coyote brush scrub, poison oak scrub, and artichoke thistle fields land cover types. This land cover type meets the member rules for the wild oats and annual brome grasslands (Avena spp. – Bromus spp. Herbaceous Semi-natural Alliance). Non-native grassland is not considered sensitive.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Intermittent Stream. Intermittent streams are linear features that exhibit indicators of an ordinary high-water mark (OHWM) and due to groundwater influence, flow for a duration longer than a precipitation event but are dry for a portion of the year. The intermittent stream within the project site is defined by a clear bed and bank and exhibits OHWM indicators such as scour and wrack.

Trickles of water were observed in portions of the channel during the February 28, 2022, site visit.

However, the channel was dry at the time of the July 14, 2022, site visit. The intermittent stream receives drainage from a concrete channel from the residential community upstream (to the west).

It occurs on a steep slope, and the channel peters out when the topography flattens out and transitions into the seasonal wetland. The intermittent stream is considered sensitive and is potentially subject to CDFW, United States Army Corps of Engineers (USACE), and Regional Water Quality Control Board (RWQCB) jurisdiction.

Seasonal Wetland. Seasonal wetlands include areas which hold water for part of the year, typically during the rainy season (between October and March) and are dominated by hydrophytic vegetative cover. The seasonal wetland within the project site occurs in the northern portion of the project site, where the topography flattens out downslope of the intermittent stream. Surface water and saturation were observed in the seasonal wetland during the February 28, 2022, site visit. At the time of the July 14, 2022, site visit no surface water or saturation was observed. The wetland is dominated by bristlox-tongue (Helminthotheca echioides), harding grass (Phalaris aquatica), iris leaved rush (Juncus xiphioides), and bulrush (Schoenoplectus americanus). Himalayan blackberry and a small number of arroyo and red willows (Salix lasiolepis) occur at northern edge of the seasonal wetland. The wetland narrows substantially to an incised channel just outside of the eastern edge of the project site. The seasonal wetland is considered sensitive and is potentially subject to USACE and RWQCB jurisdiction.

Freshwater Marsh. Freshwater marshes are wetlands which hold water for long periods of time and are dominated by graminoids and other herbaceous plants. The marsh on-site is a linear wetland drainage confined by steep slopes located centrally within the project site. Inundation was observed during the February 28 and July 14, 2022, site visits, but the full duration of inundation is unknown.

It is dominated by dense bulrush with occasional small patches of cattails (Typha sp.) and is bordered by non-native annual grassland and toyon chaparral. Surface water is shallow with a very slow flow throughout the bottom of the drainage. Although this feature receives some seasonal runoff from concrete drainage channels upslope, the primary hydrological source is a culvert that drains an unknown source and was flowing at the time of the February and July site visits. The source of this water could not be confirmed, but it does include stormwater and urban residential runoff from the residential development upslope. Freshwater marsh is considered sensitive and is potentially subject to USACE and RWQCB jurisdiction.

4.4.2.8 Tree Survey
A total of 83 trees were surveyed within the project site, of which 57 trees met the Significant Tree definition under the City’s local ordinance. Four non-native tree species were identified during the survey, including: two strawberry trees (Arbutus ‘Marina’), one apple tree (Malus sp.), three Monterey pines (Pinus radiata), and two cherry trees (Prunus sp.). Three native tree species were identified during the survey, including: one toyon (Heteromeles arbutifolia), 73 coast live oaks

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37 4.4.2.9 Special-Status Plants
Based on a review of the resource databases listed in Section 4.4.2.1, 65 special-status plant species were not observed on the project site. Special-status plant species were documented in the vicinity of the project site. The species documented in the greater vicinity have unlikely or no potential to occur on the project site for the following reasons:
• Hydrologic conditions (e.g., tidal, riverine) necessary to support the special-status plant species are not present within the project site.
• Edaphic (soil) conditions (e.g., serpentine) necessary to support the special-status plant species are not present within the project site.
• Unique pH conditions (e.g., alkaline soils) necessary to support the special-status plant species are not present within the project site.
• Associated natural communities (e.g., coastal habitats, tidal marsh, vernal pools) necessary to support the special-status plant species are not present within the project site. • The project site is geographically isolated (e.g. below elevation) from the documented range of the special-status plant species.
• Land use history and contemporary management (e.g., nearby development and the spread of invasive species) has degraded the localized habitat necessary to support the special-status plant species.

4.4.2.10 Special-Status Wildlife
Based on a review of the resource databases listed in Section 4.4.2.1, 52 special-status wildlife species have been documented in the vicinity of the project site. Of the 52 special-status species known from the region, five species were determined to have a moderate or high potential to occur within the project site, including the following: White-tailed kite (Elanus leucurus), Northern harrier (Circus hudsonius [cyaneus]), Short-eared owl (Asio flammeus), Silver-haired bat (Lasionycteris noctivagans), and Hoary bat (Lasiurus cinereus). A description of the potential special-status wildlife at the project site including a description of the potential habitat within the project site is provided in Table 4.4.A, below. The remaining species are unlikely or have no potential to occur due to the following factors:
• The project site lacks suitable hostplants;
• The project site lacks suitable perennial aquatic habitat; 37 WRA, Inc. 2023. Sancerra Vista Cove Development Project – Arborist Tree Survey and Report. February 22.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Table 4.4.A: Potential Special-Status Wildlife
Scientific Name Common Name Conservation Status Potential Habitat in the Study Area Elanus leucurus White-tailed kite California Department of Fish and Wildlife (CDFW)
Fully Protected Species
Present. This species was observed foraging
within the project site during the February 28,
2022, site visit. There is suitable nesting
habitat in the form of large oak trees within
the project site.

Circus hudsonius Northern harrier CDFW Species of Special Concern
Moderate Potential. Grasslands and
scrublands within the project site may
provide suitable nesting habitat for this
species. This species has been observed in the
local area.

Asio flammeus Short-eared owl CDFW Species of Special
Concern
Moderate Potential. Grasslands and
scrublands within the project site may
provide suitable nesting habitat for this
species. This species has been observed in the
local area.

Lasionycteris
noctivagans
Silver-haired bat Western Bat Working
Group – Medium
Priority
Moderate Potential. Large oak trees within
the project site provide suitable roosting
habitat.

Lasiurus cinereus Hoary bat Western Bat Working
Group – Medium
Priority
Moderate Potential. Large oak trees within
the project site provide suitable roosting
habitat.

Source: Biological Resources Technical Report Vista Cove Project, Vallejo, Solano County, California (WRA 2024). • The project site lacks suitable wetland habitat;
• The project site is outside of the currently documented or historical range of the species; or • The project site is outside of the distribution range for known occurrences.

4.4.3 Impact Analysis
a. Would the project have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? (Less than Significant with Mitigation Incorporated, No New Impact)
Special-status species are defined as follows:

1. Species that are listed, formally proposed, or designated as candidates for listing as threatened or endangered under the federal Endangered Species Act or California Endangered Species Act.

2. Plant species assigned to California Rare Plant Ranks (CRPR) 1A, 1B, 2A, 2B, or 3.

3. Animal species designated as Species of Special Concern or Fully Protected Species by the California Department of Fish and Wildlife (CDFW).

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4. Species that meet the definition of rare, threatened, or endangered under Section 15380 of the State CEQA Guidelines.

5. Species considered as a taxon of special concern by local agencies.

As discussed in Section 4.4.2.1, 65 special-status plant species have been documented in the vicinity of the project site; however, no special-status plant species were observed on site during the habitat assessments completed for the Biological Resources Report and the species documented in the greater vicinity have unlikely or no potential to occur on the project site. Therefore, the proposed project would result in no impacts to special-status plant species.

As discussed in Section 4.4.2.1, 52 special-status wildlife species have been documented in the vicinity of the project site. Of the 52 special-status species known from the region, five species were determined to have a moderate or high potential to occur within the project site, including the following: white-tailed kite (Elanus leucurus), northern harrier (Circus hudsonius [cyaneus]), shorteared owl (Asio flammeus), silver-haired bat (Lasionycteris noctivagans), and hoary bat (Lasiurus cinereus).

Construction activities associated with the proposed project could result in direct mortality of whitetailed kite, northern harrier, short-eared owl, and other native bird species nests, which would be considered a potentially significant impact. Impacts to active nests of this species and their eggs, chicks and young could occur during the removal of trees, vegetation, or other ground-disturbing activities. These activities could result in the direct removal or destruction of active nests, as well as generate audible, vibratory and/or visual disturbances that might indirectly result in nest abandonment. To reduce potential impacts to white-tailed kite, northern harrier, short-eared owl, and native nesting birds to a less than significant level, Project Specific Mitigation Measures BIO-1a and BIO-1b would be implemented, which require the completion of pre-construction bird surveys should construction activities occur during the nesting bird season.

Project Specific Mitigation Measure BIO-1a Avoidance of Nesting Bird Season. To avoid adverse effects to the active nests of special-status
and other native bird species, tree removal,
vegetation removal, and initial ground disturbance
should be prioritized to occur during the nonnesting season, between September 1 through January 31.

Project Specific Mitigation Measure BIO-1b Pre-Construction Nesting Bird Surveys. A preconstruction nest survey for white-tailed kite, northern harrier, short-eared owl, and other native
bird species shall be conducted prior to initial
ground disturbance, including tree removal or
vegetation removal if it begins during the nesting
bird season (defined as February 1 through August
31). If active nests (containing eggs, chicks or young) are discovered during these surveys, a qualified

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) biologist shall establish a species-specific no-work
buffer around the active nest. Work may resume in
the buffer after the nesting season ends, or a
qualified biologist confirms the nest is inactive.

The removal of 69 trees from the northern half of the project site could result in direct mortality of silver-haired bat and hoary bat adults and maternity roosts, which would be considered a potentially significant impact. Impacts to active maternity roosts of this species and their pups could occur during the removal of trees, vegetation, or other ground-disturbing activities in proximity to roost sites. These activities could result in the direct removal or destruction of active roosts, as well as generate audible, vibratory and/or visual disturbances that might indirectly result in roost abandonment. To reduce potential impacts to the silver-haired bat and hoary bat to a less than significant level, Project Specific Mitigation Measures BIO-2a and BIO-2b would be implemented, which require the completion of a bat roost assessment should construction activities occur during the maternity roost season.

Project Specific Mitigation Measure BIO-2a Avoidance of Maternity Roosting Season. To avoid adverse effects to maternity roosts of special-status
and other bat species, tree removal, vegetation
removal, and initial ground disturbance should be
prioritized to occur outside the maternity roosting
season, between September 1 through April 30.

Large trees (diameter at breast height [DBH] > 24
inches) removed during this season (September 1–
April 30) shall be cut using a two-phased system
where branches and limbs are cut and left on the
ground overnight prior to chipping or removal from
the site.

Project Specific Mitigation Measure BIO-2b Pre-Construction Roost Surveys. During the maternity roost season (May 1–August 31), at least
30 days prior to the removal of any large tree (DBH
> 24 inches) a bat roost assessment shall be
conducted by a qualified biologist to determine if
potential roost habitat is present.

If no maternity roost habitat is present, trees shall
be removed using a two-phased cut. Cut branches
and limbs shall be left on the ground overnight prior
to chipping or removal from the site.

If potential maternity roosting habitat is present,
the qualified biologist shall conduct an emergence
survey to determine if the roost is occupied or
assume the roost is occupied and establish a nowork buffer. If an emergence survey is conducted

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with no further measures required to protect
roosting bats. If roosting bats are detected, or the
tree is assumed to be an active roost, the tree shall
be given a 100-foot no work buffer and shall be
avoided until after the maternity roosting season is
complete. Once the maternal roosting season is
complete, tree removal shall follow the two-phase
approach for tree removal.

With implementation of Project Specific Mitigation Measures BIO-1a, BIO-1b, BIO-2a, and BIO-2b, the proposed project would not have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the CDFW or USFWS. Impacts would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
b. Would the project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? (Less than Significant with Mitigation Incorporated, No New Impact)
As discussed in Section 4.4.2.7, the following sensitive natural communities characterize the project site: holly leaf cherry – toyon – greenbark ceonothus chaparral, which is located in the central/southern portion of the project site on the steep slope above and adjacent to the freshwater marsh; intermittent stream, which is located in the northern portion of the project site; seasonal wetland, which occurs in the northern portion of the project site where the topography flattens out downslope of the intermittent stream; and freshwater marsh, which is located in the central portion of the project site. The proposed project has been designed to avoid and minimize impacts to sensitive natural communities to the greatest extent feasible. The design plans account for total avoidance of the toyon chapparal land cover type, keeping the area south of the freshwater marsh as open space. Additionally, the project plans to avoid the intermittent stream, freshwater marsh, and riparian vegetation. However, the proposed project would convert 0.49 acre of the seasonal wetland into a stormwater basin on the project site. Although the stormwater basin would be vegetated and seasonally inundated, it would result in permanent loss of the seasonal wetland on the project site. This would be a potentially significant impact. To reduce potential impacts to the seasonal wetland, Project Specific Mitigation Measure BIO-3a would be implemented, which requires compensatory mitigation for permanent loss of the seasonal wetland.

Project Specific Mitigation Measure BIO-3a Compensatory Mitigation for Loss of Seasonal Wetland. Compensatory mitigation for permanent
loss of 0.49 acre of the seasonal wetland shall be
required. Mitigation may be satisfied through
purchase of mitigation bank credits from an
approved mitigation bank, payment of in-lieu fees

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organization (e.g., local land trust), for
implementation of compensatory mitigation
projects, or via a permittee responsible mitigation
involving creation, restoring, or enhancing
analogous habitat. The ratio for acres of mitigation
to acres impacted shall be 1:1.

Additionally, because of the proximity of the riparian and freshwater marsh land cover types to the construction footprint, the proposed project could result in increased sedimentation to the freshwater marsh or damage to roots of riparian trees due to soil disturbance and grading completed during construction of the proposed project. This would be a potentially significant impact. To reduce potential project specific impacts to the riparian and freshwater marsh and riparian trees to a less than significant level, Project Specific Mitigation Measures, BIO-4a, BIO-4b, and BIO-4c would be implemented during project construction which require installation of construction fencing or flagging to delineate the riparian and freshwater marsh boundaries, utilization of erosion control measures, and implementation of tree protection measures.

Project Specific Mitigation Measure BIO-4a Construction Fencing. Prior to ground-disturbing activities, construction fencing or flagging shall be
installed to delineate the riparian and freshwater
marsh boundaries. The fencing will be checked
regularly during construction activities to ensure
that the fencing remains intact and functional, and
that encroachment has not occurred into the
sensitive habitat or boundary; any repairs to the
fence or encroachment correction will be conducted
immediately. At the end of the project all temporary
flagging, fencing, or other materials would be
removed from the work areas and vicinity of the
channel.

Project Specific Mitigation Measure BIO-4b Construction Best Management Practices. Erosion control measures would be utilized throughout all
phases of the project where sediment runoff from
construction may potentially enter nearby waters.

Appropriate sediment and erosion control Best
Management Practices (BMPs) (e.g., use of silt
fencing and/or straw waddles around the perimeter
of the construction zone) will be implemented
during and following construction to minimize
surface runoff originating from the project and
thereby protect water quality of the freshwater
marsh. Erosion control structures would be

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or replaced as needed.
i. Prior to construction, a Stormwater Pollution
Prevention Plan (SWPPP) would be developed.

The plan would include the implementation and
maintenance of erosion control measures.
ii. Prior to construction, an Accidental Spill
Prevention and Cleanup Plan would be
prepared. This plan would include required spill
control absorbent material, for use beneath
stationary equipment, to be present on-site and
available at all times.
iii. No fueling, cleaning, or maintenance of vehicles
or equipment would take place within any areas
where an accidental discharge may cause
hazardous materials to enter waterways.
iv. Any equipment or vehicles used for the project
would be checked and maintained daily to
prevent leaks of fluids that could be deleterious
to aquatic habitats.
v. All equipment would be cleaned before arriving
on the site and before removal from the site to
prevent spread of invasive plants.
vi. To avoid establishment of invasive, non-native
plant species on or adjacent to the project area,
the following measures will be implemented:
a. Vegetation disturbances will be limited to
those areas identified on construction plans
and maps as slated for development or
construction staging.
b. Erosion and sediment control materials will
be certified as weed-free.
vii. Staging and storage areas for equipment,
materials, fuels, lubricants and solvents would
be located outside of the stream channel banks
and outside of nearby waters.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) viii. Stationary equipment such as motors, pumps,
and generators, located adjacent to aquatic
features would be positioned over secondary
containment sufficient to arrest a catastrophic
failure.
ix. Stockpiles of excavated soil or other materials
would be covered when not in active use (i.e.
would not be used or moved for 72 hours). All
trucks hauling soil, sand, and other loose
materials would be covered.

Project Specific Mitigation Measure BIO-4c Tree Protection Measures. In order to protect trees adjacent to the project area:
i. Trees not proposed for removal but adjacent to
project activities shall have orange
construction fencing installed at the dripline.

This shall be known as the tree protection zone
(TPZ).
ii. Work within the TPZ shall be minimized to the
maximum extent feasible.
iii. If work must occur within the TPZ, the fence
can be removed temporarily, the tree trunk
shall be wrapped in a waddle, and the fence
shall be placed back as soon as work is
completed.
iv. All equipment and stockpiles must be in
designated staging areas away from all TPZ.
v. All trees to be removed shall be felled away
from any trees to be avoided.
vi. If trees not proposed for removal require
pruning, pruning shall follow ANSI A300
standards or be performed by a certified
arborist.
vii. If any roots are exposed from trees to be
avoided, roots can be pruned up to the
diameter of 2 inches and pruned at 90-degree
angles. The roots shall be covered by a damp
burlap sack or damp towel while exposed. (LTS)

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -46 With implementation of Project Specific Mitigation Measures BIO-3a, BIO-4a, BIO-4b, and BIO-4c, the proposed project would not have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations, or by the CDFW or USFWS. Impacts would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. c. Would the project have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? (Less than Significant with Mitigation Incorporated, No New Impact)
As discussed in Section 4.4.2.7, the project site contains the following riparian areas: intermittent stream, which is located in the northern portion of the project site; seasonal wetland, which occurs in the northern portion of the project site where the topography flattens out downslope of the intermittent stream; and freshwater marsh, which is located in the central portion of the project site.

The proposed project is designed to avoid the freshwater marsh in the southern half of the project site and the intermittent stream within the project site. However, the proposed project would convert 0.49 acre of the seasonal wetland into a stormwater basin within the project site. Although the stormwater basin would be vegetated and seasonally inundated, it would result in permanent loss of the seasonal wetland within the project site. Additionally, because of the proximity of the riparian and freshwater marsh land cover types to the construction footprint, the proposed project could result in increased sedimentation to the freshwater marsh or damage to roots of riparian trees. This would be a potentially significant impact.

To reduce potential impacts to the seasonal wetland, riparian, and freshwater marsh to a less than significant level, Project Specific Mitigation Measures BIO-3a, BIO-4a, BIO-4b, and BIO-4c would be implemented, which require compensatory mitigation for permanent loss of the seasonal wetland, installation of construction fencing or flagging to delineate the riparian and freshwater marsh boundaries, utilization of erosion control measures, and implementation of tree protection measures. With implementation of Project Specific Mitigation Measures BIO-3a, BIO-4a, BIO-4b, and BIO-4c the proposed project would not have a substantial adverse effect on State or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means. Impacts would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
d. Would the project interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? (Less Than Significant Impact, No New Impact) Wildlife movement includes migration (i.e., usually annual roundtrip), inter-population movement (i.e., long-term genetic flow), and small travel pathways (i.e., daily movement corridors within an animal’s territory). While small travel pathways usually facilitate movement for daily home range activities such as foraging or escape from predators, they also provide connection between outlying

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) populations and the main corridor, permitting an increase in gene flow among populations. In the San Francisco Bay Area, landscape elements that facilitate local and/or regional wildlife movement include stream drainages, canyons, ridges, or other prominent natural or human-made landscape features.

Habitat linkages provide connections between larger habitat areas that are separated by development. Wildlife corridors are similar to linkages but provide specific opportunities for animals to disperse or migrate between areas. A corridor can be defined as a linear landscape feature of sufficient width to allow animal movement between two comparatively undisturbed habitat fragments. Adequate cover is essential for a corridor to function as a wildlife movement area. It is possible for a habitat corridor to be adequate for one species yet still inadequate for others. Wildlife corridors are features that allow for the dispersal, seasonal migration, breeding, and foraging of a variety of wildlife species. Additionally, open space can provide a buffer against both human disturbance and natural fluctuations in resources.

No native wildlife nursery sites are present within the project site, and the project site is not within a designated wildlife corridor.38 Additionally, the project site does not function as a fisheries movement corridor as there are no streams or rivers within the project site capable of supporting fish.39 The project site is located within a much larger tract of housing developments intersected with several highways and non-native grasslands in Solano County. The Benicia State Recreation Area is approximately 1,000 feet southeast of the project site; however, the project site does not provide connection to other tidal marsh habitats, nor does it contain such habitat. While common wildlife species presumably utilize the site to some degree for movement at a local scale, the project site itself does not provide corridor functions beyond connecting similar ruderal grassland parcels to surrounding areas. Therefore, the proposed project would not interfere with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors or impede the use of native wildlife nursery sites, and impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. e. Would the project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? (Less than Significant with Mitigation Incorporated, No New Impact)
Chapter 16.504.07 of the City of Vallejo Municipal Code requires a tree removal permit for impacts to existing mature trees located in non-residential zoning districts if they are over 24 inches in diameter measured six inches above natural grade. Protected trees may be removed with the permission of the City upon submittal of an arborist's report, which determines that the tree is in poor health and not likely to survive; if the trees constitute a high fire hazard or a threat to persons, structures, or property; or, if they impede public works projects. Trees to be removed must be shown on the landscaping and irrigation plan and detailed on a tree inventory chart. 38 WRA, Inc. 2024. Biological Resources Technical Report Vista Cove Project, Vallejo, Solano County, California. February. 39 Ibid.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -48 A total of 69 trees would be removed, including 47 significant trees that are protected under the City’s tree protection ordinance.40,41 In compliance with the City’s Tree Protection Ordinance, the project applicant has prepared an arborist report,42 would implement protection measures for trees to be retained, would pay required permit application fees, and would replace removed trees at a ratio of at least three new trees for every tree removed except for the fire-prone species identified in the City’s Municipal Code. Trees would be replaced at a ratio of 3 new trees for every tree removed, for a total of 141 trees that would be planted.43 The exact number of replacement trees required for mitigation of removed trees would be identified as part of the final landscape plan to be reviewed and approved by the City. Therefore, the proposed project would not conflict with the City’s Tree Protection Ordinance.

Chapter 4, Nature and Built Environment, of the Vallejo General Plan 2040 establishes goals, policies, and actions to protect natural resources within the city. Specifically, Policies NBE-1.1 and NBE-1.2 state:

Policy NBE-1.1. Natural Resources. Protect and enhance hillsides, waterways, wetlands, occurrences of special-status species and sensitive natural communities, and aquatic and important wildlife habitat through land use decisions that avoid and mitigate potential environmental impacts on these resources to the extent feasible.

Policy NBE-1.2. Sensitive Resources. Ensure that adverse impacts on sensitive biological resources, including special-status species, sensitive natural communities, and wetlands are avoided and mitigated to the greatest extent feasible as development takes place.

As described above, trees on the project site could provide nesting and/or roosting habitat for protecting bird and bat species. Additionally, the proposed project would convert 0.49 acre of the seasonal wetland into a stormwater basin within the project site and construction activities could result in increased sedimentation to the freshwater marsh or damage to roots of riparian trees due to the proximity of the construction footprint to the riparian and freshwater marsh land cover types.

These impacts could interfere with the local policies listed above protecting biological resources and is a potentially significant impact.

To reduce potential conflicts with local policies protecting biological resources, implementation of Project Specific Mitigation Measures BIO-1a, BIO-1b, BIO-2a, BIO-2b, BIO-3a, BIO-4a, BIO-4b, and BIO-4c would be required. These measures require the completion of pre-construction surveys should construction activities occur during the nesting bird season; the completion of a bat roost assessment should construction activities occur during the maternity roost season; compensatory mitigation for permanent loss of the seasonal wetland; installation of construction fencing or 40 WRA, Inc. 2023. Sancerra Vista Cove Development Project – Arborist Tree Survey and Report. February 22. 41 Vallejo, City of. Vallejo, California – Municipal Code, Title 16 – Zoning, Part V – Site Development Standards, Chapter 16.504 – Landscaping, Section 16.504.07 – Tree protection. 42 WRA, Inc. 2023. Sancerra Vista Cove Development Project – Arborist Tree Survey and Report. February 22. 43 Ibid.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) flagging to delineate the riparian and freshwater marsh boundaries; utilization of erosion control measures; and implementation of tree protection measures.

Compliance with the City’s Tree Protection Ordinance and implementation of Project Specific Mitigation Measures BIO-1a, BIO-1b, BIO-2a, BIO-2b, BIO-3a, BIO-4a, BIO-4b, and BIO-4c would ensure that the proposed project would reduce all impacts on biological resources to a less than significant level and thus not conflict with any local policies or ordinances protecting biological resources, including General Plan Policies NBE-1.1 and NBE-1.2. This impact would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
f. Would the project conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? (No Impact, No New Impact)
The project site is not located within the boundaries of any adopted Habitat Conservation Plan (HCP), Natural Community Conservation Plan (NCCP), or other approved local, regional, or state habitat conservation plan. Although the Solano County HCP is currently in development, it does not identify individual, privately held properties such as the project site as habitat.44 According to the Solano County HCP, the HCP is not planning to designate private properties as preserves; instead, it would focus on lands with conservation easements, existing mitigation banks, or publicly owned habitat. As such, the project would not conflict with the provisions of any adopted conservation plan. No new impacts or substantially more severe significant impacts would occur with implementation of the proposed project, compared to those analyzed in the General Plan EIR. 44 WRA, Inc. 2024. Biological Resources Technical Report Vista Cove Project, Vallejo, Solano County, California. February.

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4.5 CULTURAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5?
b. Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5?
c. Disturb any human remains, including those interred
outside of formal cemeteries?

4.5.1 Prior Environmental Analysis
Chapter 4.4 of the General Plan EIR analyzed impacts to cultural and paleontological resources associated with build out of the General Plan, and determined adverse changes could occur to the significance of archaeological and paleontological resources through future development due to the lack of specific implementing procedures. Therefore, the General Plan EIR prescribed Mitigation Measures CULT-2 and CULT-3, which details procedures in the event that archaeological or paleontological resources are encountered during future development. With implementation of General Plan EIR Mitigation Measures CULT-2 and CULT-3, impacts on cultural resources were considered reduced to less than significant. Additionally, the General Plan includes the following goals, policies, and actions related to cultural resources which would be applicable to the proposed project:
• Policy NBE-1.9 Cultural Resources: Protect and preserve archaeological, historic, and other cultural resources.
○ Action NBE-1.9A: Continue to require that land use activities comply with State requirements and follow best practices to ensure that cultural resources are not impacted and that appropriate agencies and technical experts are involved in the evaluation and protection of resources and sites.
○ Action NBE-1.9B: Maintain a dialogue with local Native American groups regarding sensitive cultural resources in Vallejo.

4.5.2 Background
The analysis of potential impacts to cultural resources is based on a site-specific cultural resources assessment prepared for the proposed project, prepared by LSA in March 2025, which is included in Appendix D of this Initial Study.
45 This assessment included a cultural resources records search, a 45 LSA Associates, Inc. (LSA). 2025. Cultural Resources Assessment, Vista Cove Development Project, Vallejo, Solano County, California. March.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) review of historic-period aerial imagery and maps, and a pedestrian archaeological survey of the project site.

An archaeological records search was conducted on September 6, 2024, at the Northwest Information Center (NWIC) at Sonoma State University. The NWIC is the official repository for cultural resources records for Solano County and maintains an extensive inventory of previously recorded archaeological sites and prior survey coverage. The records search included a one-mile radius around the project site and reviewed all available documentation of prehistoric and historicperiod resources, as well as prior cultural resource surveys and excavation reports.

In February 2025, historic-period aerial photographs and topographic maps were reviewed using the Nationwide Environmental Title Research (NETR) Online database. This review provided supplemental information regarding historical land use within and surrounding the project area.

An intensive pedestrian survey of the project site was conducted on January 20, 2025, by a qualified archaeologist. The survey was performed using linear transects spaced approximately 20 to 30 meters (65.6 to 98.4 feet) apart. The entire accessible area of the project site was inspected, with particular attention given to areas containing exposed native soils, rock outcrops, and rodent disturbances. All visible ground surfaces were carefully examined for the presence of prehistoric or historic-period artifacts, features, or other cultural deposits.

4.5.2.1 Natural Setting
This section summarizes the natural setting of the project site and its vicinity, including a general description of the climate and watershed, flora and fauna, and geology.

Climate and Watershed. The project region is characterized by a coastal climate, with mild summers and winters. Rainfall averages 24 inches annually. The project area is transected by two ephemeral drainages,46 which drain to Benicia State Park in the east, where stormwater runoff converges and is directed to the Carquinez Strait.

Flora and Fauna. At an elevation of approximately 250 feet, the proposed project is just within the Lower Sonoran Life Zone of California , which ranges from below sea level to 3,500 feet. Monterey pine, coast live oak, poison oak, and other native species were noted on the property (particularly xeric grasses, oats, barley, and brome). Extensive fauna are known locally, including many endemic species of reptiles, birds, and insects.

The coastal environment of California hosted a rich variety of abundant floral and faunal resources that fostered a particularly dense Native American occupation of this region during prehistoric times, especially the coastal corridor within a day’s “commuting” distance of fresh water.

Geology. Vallejo is within the Coast Ranges geomorphic province of California. The geological setting along the Coast Ranges is notably different between the East and West sides of the San Andreas 46 A stream that has flowing water only during or for a short duration after precipitation events in a typical year.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -52 fault. Vallejo lies to the east of the San Andreas fault, which is characterized by Mesozoic rocks of the Franciscan Complex, the Great Valley Sequence, and the Jurassic Coast Range ophiolite.

The boundaries of the proposed project are situated within the Upper Great Valley Sequence, which dates to the Late Cretaceous. The Upper Great Valley Sequence (Ku) consists of sandstone, siltstone, shale, and minor conglomerate.

4.5.2.2 Cultural Setting
This section summarizes the cultural setting of the project site and its vicinity, including a summary of the prehistory, ethnography, and general history of the project area.

Prehistory. Chronologies of prehistoric cultural change in the Northern California area have been attempted numerous times; however, no single description is universally accepted, as the various chronologies are based primarily on material developments identified by researchers familiar with sites in a particular region and variation exists essentially due to the differences in those items found at the sites. Small differences occur over time and space, which combine to form patterns that are variously interpreted. One of the regional chronologies commonly referenced in the archaeological literature is the Lower Archaic (10,000 to 6,000 A.D.), followed by the Initial Middle Archaic (6,000 to 4,500 BP), Terminal Middle Archaic (4,500 to 2,500 BP), Upper Archaic (2,500 to 1,300 BP) and, finally, the Emergent (1,200 to 200 BP).

Ethnography. The proposed project is within the traditional cultural territory of the Patwin. Tribal territories were somewhat fluid and changed over time. Like other Native American groups in Northern California, the Patwin were semi-nomadic hunter-gatherers who subsisted on seasonably available plant and animal resources. The first written accounts of Native American groups in California were by Spanish missionaries in the late 18th century. With the Spanish intrusion came a drastic change in lifestyle for the Native Americans of California. Incorporation of the indigenous populations into the mission system involved conflict, forced labor, and relocation along with decimation by European diseases, all of which led to the disruption of native cultures and changes in subsistence and land use practices. Cattle ranches/farms were established on or near ancestral Native American villages, primarily in the major drainages conducive to horticulture and animal husbandry. Water was diverted for irrigation and stock. Within a short time, the missions controlled many ranchos where Indians lived and worked.

History. In California, the historic era is generally divided into three periods: the Spanish Period (1769–1821), the Mexican Period (1821–1848), and the American Period (1848–present). Solano County was created from part of the Sonoma territory in 1850 by the first elected Legislature of the territory of California. Solano County is therefore one of the original 27 counties in California.

General Vallejo, an instrumental figure in shaping Alta California, requested that this county was named after Chief Solano, a Suisun and Patwin leader who presided over this land prior to California’s statehood. Seven of the 12 townships created during Solano County’s early days have incorporated into cities. These include Benicia (1850 and 1851), Vallejo (1868), Suisun City (1856), Dixon (1878), Vacaville (1892), Rio Vista (1893), and Fairfield (1903).

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Vallejo. The region that became Vallejo was first mapped by Spanish colonizers in 1775. However, this area remained largely unshaped by colonial influence until 1844, when General Vallejo received this area as a part of the larger Rancho Soscol land grant. General Vallejo donated land and funds for the construction of a capital city, named Vallejo, in the newly annexed state of California in 1851.

Vallejo served as a temporary capitol until Benecia was formally recognized as the capital in 1853.

Mare Island became the country’s first permanent U.S. Naval station on the West Coast in September 1854. Vallejo formally incorporated in 1868 and experienced booms of growth reflecting periods of U.S. Naval growth during the Spanish-American War and World War I.

4.5.3 Impact Analysis
a. Would the project cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5? (Less Than Significant Impact, No New Impact) The project site is vacant and undeveloped and is covered primarily with non-native annual grassland and scattered mature trees. No buildings or structures are present within the project area in historic period aerial photos or as indicated on maps dating back to 1948.47 As discussed previously in Section 4.5.1, on September 6, 2024, a records search to identify previously recorded prehistoric and historic cultural resources and cultural resource surveys within one mile of the project area was conducted at the NWIC of the California Historical Resources Information System at Sonoma State University. According to the NWIC records search, no cultural resources were recorded within the project area, although eight historic age resources are documented within 0.5 mile. The nearest historic resources to the project site are within 0.25 mile of the project boundary.

Based on the background research conducted by LSA, it was determined that there are no known archaeological resources on the project site that would qualify as “historical resources” as defined under CEQA. Furthermore, as the project site is undeveloped and there are no existing structures at the project site to qualify as an “historical resource” as defined under CEQA. Therefore, the proposed project would have no impact associated with a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 of the State CEQA Guidelines. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. b. Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5? (Less than Significant with Mitigation Incorporated, No New Impact)
A “substantial adverse change” to a historical resource, according to PRC Section 5020.1(q), “means demolition, destruction, relocation, or alteration such that the significance of a historical resource would be impaired.” According to the NWIC records search, no cultural resources were recorded 47 LSA Associates, Inc. (LSA). 2025. Cultural Resources Assessment, Vista Cove Development Project, Vallejo, Solano County, California. March.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -54 within the project area, although eight historic age resources are documented within 0.5 mile. The nearest historic resources to the project site are within 0.25 mile of the project boundary.

An archaeological pedestrian field survey of the project site was conducted on January 20, 2025.

During the field survey, archaeologists did not discover any cultural resources (including prehistoric or historic archaeological sites or historic-period buildings) on the project site or within the project site boundaries. The field survey indicated that there was light disturbance in some areas of the project site, where modern refuse was noted throughout the project area; however, overall visibility was generally limited by existing vegetation cover. No cultural resources were identified. Based on these results, the Cultural Resources Assessment determined that the project site has a low potential for in situ subsurface cultural resources due to the severe slopes and adjacent developments. The project would implement standard measures to address the potential to disturb subsurface archaeological resources consistent with the General Plan EIR mitigation measures to mitigate the impact to a level of less than significant. CEQA California Code of Regulations, Title 14, Chapter 3, Sections 15064.5 [e and f] require a lead agency to establish protocols for discovery of unknown archaeological resources. As such, the proposed project shall be required to implement Project Specific Mitigation Measure CUL-1 as a standard requirement in accordance with State law.

Project Specific Mitigation Measure CUL-1 Unknown Discovery of Archaeological Resources.

Should an archaeological deposit be encountered
during project subsurface construction activities, all
ground-disturbing activities within 25 feet shall be
redirected and a qualified archaeologist meeting
the Secretary of the Interior’s Professional
Qualifications Standards for Archaeology contacted
to assess the situation, determine if the deposit
qualifies as a historical resource, consult with
agencies as appropriate, and make
recommendations for the treatment of the
discovery.

If the deposit is found to be significant (i.e., eligible for listing in the California Register of Historical
Resources), the project applicant shall be
responsible for funding and implementing
appropriate mitigation measures. Mitigation
measures may include recording the archaeological
deposit, data recovery and analysis, and public
outreach regarding the scientific and cultural
importance of the discovery. Upon completion of
the selected mitigations, a report documenting
methods, findings, and recommendations shall be
prepared by the qualified archaeologist and
submitted to the City of Vallejo for review, and the
final report shall be submitted to the Northwest

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Significant archaeological materials shall be
submitted to an appropriate local curation facility
and used for future research and public interpretive
displays, as appropriate.

Project Specific Mitigation Measure CUL-1 outlines procedures if archaeological resources are discovered during construction, such as work stoppage within 25 feet of the find, and a qualified archaeologist must evaluate the discovery. If the deposit is determined to be a significant historical resource, the project applicant must implement standard measures for the treatment of archaeological resources, which may include documentation, excavation, analysis, and public outreach. A final report will be submitted to the City and archived at the NWIC with significant materials curated for future research or public display. With the implementation of Project Specific Mitigation Measure CUL-1, the proposed project would not result in new significant or substantially greater impacts to previously undiscovered archaeological resources, as the resources would be avoided, recovered, and evaluated, as needed.

At the completion of project construction, the proposed project would not result in further disturbance of native soils on the project site and, therefore, project operations would have no potential to impact previously undiscovered archaeological resources.

Therefore, with implementation of Project Specific Mitigation Measure CUL-1, construction and operation of the proposed project would not result in a new significant or substantially more severe impact on cultural resources due to a substantial adverse change in the significance of an archaeological resource as defined in Section 15064.5 of the State CEQA Guidelines. Impacts would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
c. Would the project disturb any humans remains, including those interred outside of formal cemeteries? (Less than Significant with Mitigation Incorporated, No New Impact) No human remains are documented/known to be on the project site. Furthermore, severe slopes and adjacent developments indicate that project site retains low potential for in situ subsurface cultural resources, as documented in Appendix D. Therefore, the likelihood of discovering unknown human remains during construction of the proposed project is low, which is consistent with its prior analysis in the General Plan EIR. However, there is still potential for unknown human remains to be discovered during construction activities, and impacts would be potentially significant if the project does not implement standard measures required by the Health and Safety Code section 7050.5 as summarized below.

In the unlikely event that human remains are discovered during construction activities, the Construction Contractor would be required to implement Project Specific Mitigation Measure CUL-2, which requires compliance with the State’s Health and Safety Code for the treatment of human remains.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -56 Project Specific Mitigation Measure CUL-2 Protocol for Human Remains Discovery. If human remains are encountered, State Health and Safety
Code Section 7050.5 states that no further
disturbance shall occur until the County Coroner
has made a determination of origin and disposition
pursuant to State Public Resources Code (PRC)
Section 5097.98. The County Coroner must be
notified of the find immediately. If the remains are
determined to be Native American, the County
Coroner would notify the Native American Heritage
Commission (NAHC), which would determine and
notify a Most Likely Descendant (MLD), and the
following provisions shall apply:
• The Medical Examiner shall immediately be
notified, ground disturbing activities in that
location shall cease within 25 feet of the
discovery and the Tribe shall be allowed,
pursuant to California PRC Section 5097.98(a) to
inspect the site of the discovery and make
determinations as to how the human remains
and grave goods should be treated and disposed
of with appropriate dignity.
• The Tribe shall complete its inspection and make
its MLD recommendation within forty-eight (48)
hours of getting access to the site. The Tribe shall
have the final determination as to the disposition
and treatment of human remains and grave
goods. Said determination may include
avoidance of the human remains, reburial onsite or reburial on tribal or other lands that will not be disturbed in the future.
• The Tribe may wish to rebury said remains and
grave goods or ceremonial and cultural items on
or near the site of their discovery, in an area
which will not be subject to future disturbances
over a prolonged period of time. Reburial of
human remains shall be accomplished in
compliance with California PRC Sections
5097.98(a) and (b). The term “human remains”
encompasses more than human bones because
the Tribe’s traditions call for the burial of
associated cultural items with the deceased
(funerary objects), and/or the ceremonial

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) burning of Native American human remains,
funerary objects, grave goods, and animals.

Ashes, soils, and other remnants of these
burning ceremonies, as well as associated
funerary objects and unassociated funerary
objects buried with or found near the Native
American remains are to be treated in the same
manner as bones or bone fragments that remain
intact.
• Unless otherwise required by law, the site of any
reburial of Native American human remains shall
not be disclosed and will not be governed by
public disclosure requirements of the California
Public Records Act (California Government Code
Section 6250 et. seq). The Medical Examiner
shall withhold public disclosure of information
related to such reburial pursuant to the specific
exemption set forth in California Government
Code Section 6254(r). The Tribe will require that
the location for reburial is recorded with the
California Historic Resources Inventory System
(CHRIS) on a form that is acceptable to the CHRIS
center. The Tribe may also suggest that the
landowner enter into an agreement regarding
the confidentiality of site information that will
run with title on the property.
• Treatment of all cultural items, including
ceremonial items and archaeological items will
reflect the religious beliefs, customs, and
practices of the Tribe. All cultural items,
including ceremonial items and archaeological
items, which may be found at a project site
should be turned over to the Tribe for
appropriate treatment, unless otherwise ordered
by a court of agency of competent jurisdiction.

The project applicant should waive any and all
claims to ownership of Tribal ceremonial and
cultural items, including archaeological items,
which may be found on a project site in favor of
the Tribe. If any intermediary (e.g., an
archaeological retained by the project applicant)
is necessary, said entity or individual shall not
possess those items for longer than is reasonably
necessary, as determined solely by the Tribe.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -58 • If additional significant sites or sites not
identified as significant in the environmental
review process, but later determined to be
significant are located within a project impact
area, such sites will be subjected to further
archaeological and cultural significance
evaluation by the project applicant, Solano
County and the Tribe to determine if additional
mitigation measures are necessary to treat sites
in a culturally appropriate manner consistent
with CEQA requirements for mitigation of
impacts to cultural resources. If there are human
remains present that have been identified as
Native American, all work will cease for a period
of up to 30 days in accordance with Federal Law.

Project Specific Mitigation Measure CUL-2 outlines procedures to follow if Native American human remains are discovered during project development. If remains are found, ground-disturbing activities within 25 feet of the discovery area must immediately stop, and the County Coroner, Medical Examiner, and Tribe must be notified in accordance with State law. The NAHC would identify a Most Likely Descendant (MLD), and the Tribe, through the MLD, would have 48 hours to inspect the site and determine the appropriate dignified treatment of the remains and associated items. Treatment options may include avoidance, on-site reburial, or reburial on other lands that will not be disturbed in the future. All funerary objects, ceremonial items, and related materials— such as ashes and soil from burning ceremonies—must be treated as human remains, and the Tribe retains the right to manage their handling and final disposition, including requiring confidentiality of reburial locations. Any additional significant cultural sites identified during construction will require further evaluation and mitigation in consultation with Solano County and the Tribe, and work will pause for up to 30 days if Native American remains are present, in accordance with federal law.

With implementation of Project Specific Mitigation Measure CUL-2, potential impacts to previously undiscovered human remains would be less than significant.

At the completion of project construction, the proposed project would not result in further disturbance of native soils on the project site and, therefore, project operations would have no potential to impact previously undiscovered human remains.

Therefore, with implementation of Project Specific Mitigation Measure CUL-2, construction and operation of the proposed project would have a less than significant impact on undiscovered human remains. Impacts would be less than significant with mitigation incorporated. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those impacts analyzed in the General Plan EIR.

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4.6 ENERGY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary
consumption of energy resources during project
construction or operation?
b. Conflict with or obstruct a state or local plan for
renewable energy or energy efficiency?

4.6.1 Prior Environmental Analysis
Chapter 4.15 of the General Plan EIR analyzed impacts related to energy associated with build out of the General Plan, and determined that either no impact or less than significant impacts would occur due to compliance with existing energy standards including the California Code of Regulations Title 24, the City’s Green Building Code, CALGreen Building Code requirements, the City’s Climate Action Plan and GHG reduction measures, and other applicable State and local energy efficiency measures.

No mitigation measures were prescribed. There are no General Plan goals, policies, or actions related to energy which would be applicable to the proposed project.

4.6.2 Background
Electricity and gas service is provided to the project site by Pacific Gas and Electric Company (PG&E).

Energy demand is typically associated with day-to-day operations and fuel consumption associated with project construction. The proposed project would result in a small increase in demand for electricity and gasoline. The discussion and analysis provided below is based on data included in the California Emissions Estimator Model version 2022.1 (CalEEMod) output, which are included in Appendix A.

4.6.3 Impact Analysis
a. Would the project result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources during project construction or operation? (Less than Significant Impact, No New Impact) Construction-Period Energy Use. The proposed project would require grading, site preparation, and building activities during construction. Construction of the proposed project would require energy for the manufacture and transport of construction materials, preparation of the site for grading activities, and construction of the proposed residential development. Petroleum fuels (e.g., diesel and gasoline) would be the primary sources of energy for these activities. In order to increase energy efficiency on the site during project construction, the idling times for construction vehicles would be restricted to 5 minutes or less and construction workers would be required to shut off idle equipment, as required by the Air District. In addition, construction activities are not anticipated to result in inefficient use of energy, as gasoline and diesel fuel would be supplied by construction contractors which would conserve the use of their supplies to minimize their costs on the project.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -60 Energy usage on the project site during construction would be temporary in nature, and no unusual project characteristics would necessitate the use of construction equipment that would be less energy-efficient than at comparable construction sites in the region or the State. Therefore, construction energy impacts would be less than significant.Operational Energy Use.Operational energy usage is typically associated with natural gas use, electricity consumption, and fuel used for vehicle trips. The proposed project would also result in diesel usage associated with the standby backup generator; however, the backup generator would operate for up to 50 hours annually, primarily for testing purposes. Therefore, use of the emergency backup generator is not expected to substantially increase diesel fuel usage and is not evaluated further. Electricity and natural gas consumption were estimated for the project using default energy intensities by land use type in CalEEMod. The 2022 Title 24 Building Energy Efficiency Standards (Title 24 Standards) contain energy efficiency requirements for newly constructed buildings, additions to existing buildings, and alterations to existing buildings. The Title 24 Standards establish performance metrics in the form of an “energy budget” based on energy consumption per square foot of floor space. For this reason, Title 24 Standards include both a prescriptive option, allowing builders to comply by using methods known to be efficient, and a performance option, allowing builders complete freedom in their designs provided the building achieves the same overall efficiency as an equivalent building using the prescriptive option. Reference appendices are adopted along with the Title 24 Standards containing data and various compliance tools to help builders achieve compliance.

In addition, the proposed project would result in energy usage associated with gasoline to fuel project-related trips. Based on the CalEEMod analysis, the proposed project would result in approximately 1,897,969 vehicle miles traveled (VMT) per year.48 The average fuel economy for light-duty vehicles (autos, pickups, vans, and sport utility vehicles [SUVs]) in the United States has steadily increased from about 14.9 miles per gallon (mpg) in 1980 to 22.8 mpg in 2022, the year for which the most recent data is available.49 The average fuel economy for heavy-duty trucks in the United States has also steadily increased, from 5.7 mpg in 2013 to a projected 8.0 mpg in 2021.50 Therefore, using the United States Environmental Protection Agency (EPA) fuel economy estimates for 2020, the proposed project would result in the consumption of approximately 67,760 gallons of gasoline per year and 43,235 gallons of diesel fuel per year.

Electricity and natural usage estimates associated with the proposed project are shown in Table 4.6.A.
48 To be conservative, LSA utilized default vehicle miles traveled in CalEEMod, which estimates trip lengths for vehicle trips traveling between home, work, shopping, and other locations (e.g., school, park, gym, etc.). 49 United States Department of Transportation (USDOT). 2023. “Table 4‐23: Average Fuel Efficiency of U.S.

Light Duty Vehicles.” Website: https://www.bts.gov/content/average-fuel-efficiency-us-light-dutyvehicles (accessed March 26, 2025). 50 California Energy Commission (CEC). 2015. Medium and Heavy-Duty Truck Prices and Fuel Economy 2013– 2026. Website: efiling.energy.ca.gov/getdocument.aspx?tn=206180 (accessed March 26, 2025).

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Table 4.6.A: Estimated Annual Energy Use of Proposed Project Electricity Use (kWh/yr) Natural Gas Use (therms/yr) Gasoline (gal/yr) Diesel (gal/yr) 434,811 14,839 67,760 43,235
Source: Compiled by LSA (March 2025).
gal/yr = gallons per year kWh/yr = kilowatt-hours per year therms/yr = therms per year As shown in Table 4.6.A, the estimated potential increased electricity demand associated with the proposed project is 434,811 kilowatt-hours (kWh) per year. In 2022, California consumed approximately 287,826 gigawatt-hours (GWh), or 287,826,110,475 kWh.51 Of this total, Solano County consumed 3,225 GWh, or 3,225,398,734 kWh.52 Therefore, electricity demand associated with the proposed project would be less than 0.1 percent of Solano County’s total electricity demand.

Additionally, as shown in Table 4.6.A, the estimated potential increase in natural gas demand associated with the proposed project is 14,839 therms per year. In 2022, California consumed approximately 11,171 million therms (11,710,641,194 therms).53 Of this total, Solano County consumed 248 million therms (248,386,169 therms).54 Therefore, natural gas demand associated with the proposed project would be less than 0.1 percent of Solano County’s total natural gas demand.

In addition, the proposed project would result in energy usage associated with gasoline and diesel to fuel project-related trips. As shown above in Table 4.6.A, vehicle trips associated with the proposed project would consume approximately 67,760 gallons of gasoline per year and 43,235 gallons of diesel fuel per year. Based on fuel consumption obtained from CARB’s EMission FACtor model (EMFAC2021), approximately 173.0 million gallons of gasoline and approximately 55.1 million gallons of diesel fuel will be consumed from vehicle trips in Solano County in 2025. Therefore, gasoline and diesel fuel demand generated by vehicle trips associated with the proposed project would be a minimal fraction of gasoline and diesel fuel consumption in Solano County. Fuel consumption associated with vehicle trips generated by project operations would not be considered inefficient, wasteful, or unnecessary in comparison to other similar developments in the region.

In addition, proposed new development would be constructed using energy-efficient modern building materials and construction practices, and the proposed project also would use new modern appliances and equipment, in accordance with the Appliance Efficiency Regulations (Title 20, California Code of Regulations [CCR] Sections 1601 through 1608). The expected energy 51 California Energy Commission (CEC). 2024a. Energy Consumption Data Management Service. Electricity Consumption by County. Website: www.ecdms.energy.ca.gov/elecbycounty.aspx (accessed March 26, 2025). 52 Ibid. 53 California Energy Commission (CEC). 2024b. Energy Consumption Data Management Service. Gas Consumption by County. Website: https://ecdms.energy.ca.gov/gasbycounty.aspx (accessed March 26, 2025). 54 Ibid.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -62 consumption during construction and operation of the proposed project would be consistent with typical usage rates for residential uses.

PG&E is the private utility that would supply the proposed project’s electricity and natural gas services. In 2022, approximately 40 percent of PG&E’s delivered electricity came from renewable sources, including solar, wind, geothermal, small hydroelectric, and various forms of bioenergy.55 PG&E reached California’s 2020 renewable energy goal in 2017 and is positioned to meet the State’s 60 percent by 2030 renewable energy mandate set forth in Senate Bill (SB) 100. In addition, PG&E plans to continue to provide reliable service to its customers and upgrade its distribution systems as necessary to meet future demand.

Therefore, the proposed project would not result in the wasteful, inefficient, or unnecessary consumption of fuel or energy and would incorporate renewable energy or energy efficiency measures into building design, equipment use, and transportation. Construction and operation period impacts related to consumption of energy resources would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. b. Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? (Less Than Significant Impact, No New Impact)
In 2002, the State Legislature passed SB 1389, which required the California Energy Commission (CEC) to develop an integrated energy plan every 2 years for electricity, natural gas, and transportation fuels for the California Energy Policy Report. The plan calls for the State to assist in the transformation of the transportation system to improve air quality, reduce congestion, and increase the efficient use of fuel supplies with the least environmental and energy costs. To further this policy, the plan identifies a number of strategies, including assistance to public agencies and fleet operators in implementing incentive programs for zero-emission vehicles and their infrastructure needs, and encouragement of urban designs that reduce VMT and accommodate pedestrian and bicycle access.

The most recently adopted CEC energy report is the 2024 Integrated Energy Policy Report Update. 56 The 2024 Integrated Energy Policy Report Update provides the results of the CEC’s assessments of a variety of energy issues facing California. Many of these issues will require action if the State is to meet its climate, energy, air quality, and other environmental goals while maintaining energy reliability and controlling costs. The 2024 Integrated Energy Policy Report Update covers a broad range of topics, including implementation of SB 350 (Clean Energy and Pollution Reduction Act of 2015), integrated resource planning, distributed energy resources, transportation electrification, solutions to increase resiliency in the electricity sector, energy efficiency barriers faced by disadvantaged communities, demand response, transmission and landscape-scale planning, the 55 Pacific Gas & Electric (PG&E). 2023. Exploring Clean Energy Solutions. Website: https://www.pge.com/en/ about/corporate-responsibility-and-sustainability/taking-responsibility/clean-energy-solutions.html (accessed March 5, 2025). 56 California Energy Commission. 2024. 2024 Integrated Energy Policy Report Update. Docket Number: 24- IEPR-01.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) California Energy Demand Preliminary Forecast, the preliminary transportation energy demand forecast, renewable gas (in response to SB 1383), updates on Southern California electricity reliability, the natural gas outlook, and climate adaptation and resiliency.

As indicated above, energy usage on the project site during construction would be temporary in nature. In addition, energy usage associated with operation of the proposed project would be relatively small in comparison to the State’s available energy sources, and energy impacts would be negligible at the regional level. Because California’s energy conservation planning actions are conducted at a regional level, and because the project’s total impact to regional energy supplies would be minor, the proposed project would not conflict with California’s energy conservation plans as described in the CEC 2024 Integrated Energy Policy Report Update. Therefore, the proposed project would not conflict with or obstruct a State or local plan for renewable energy or energy efficiency, and this impact would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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

4.7.1 Prior Environmental Analysis
Chapter 4.5 of the General Plan EIR analyzed the geological, seismic, and soil conditions within the city, and determined that build out of the General Plan would result in less than significant impacts related to geology and soils due to compliance with existing regulatory requirements including the California Building Code, City of Vallejo Municipal Code, and the Construction General Permit, and implementation of General Plan goals, policies, and actions. Chapter 4.4 of the General Plan EIR analyzed impacts to paleontological resources associated with build out of the General Plan, and determined adverse changes could occur to the significance of paleontological resources through future development due to the lack of specific implementing procedures. Therefore, the General Plan EIR prescribed Mitigation Measure CULT-3, which details procedures in the event that paleontological resources are encountered during future development. With implementation of General Plan EIR Mitigation Measure CULT-3, impacts on paleontological resources were considered reduced to less than significant.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Additionally, the General Plan includes the following goals, policies, and actions related to geology and soils which would be applicable to the proposed project:
• Goal NBE-5: Hazard Protection: Protect life and property from natural and human-made hazards.
○ Policy NBE-5.3: Health and Safety Codes. Enforce development regulations and building code requirements to protect residents, businesses, and employees from flooding, liquefaction, earthquakes, fires, and other hazards.
○ Policy NBE-5.4: Project Location and Design. Prohibit development in any area where it is determined that the potential risk from natural hazards cannot be mitigated to acceptable levels.
■ Action NBE-5.4A: Continue to require geotechnical studies for land use proposals to determine engineering measures that may be necessary to adequately mitigate any seismic, flooding, sea level rise, landslide, erosion, or related risk. ■ Action NBE-5.4B: Continue to require drainage and erosion control measures for landslide-prone or geologically hazardous hillside areas to minimize risks to downhill areas.

4.7.2 Background
Unless otherwise noted, the following analysis is based on the Preliminary Geotechnical Exploration prepared for the proposed project57 and the peer review conducted as part of the environmental review process58. A copy of the Geotechnical Investigation and peer review are included in Appendix E of this Initial Study.

The project site is in a seismically active area, where earthquakes have the potential to subject the project to strong seismic ground shaking. There are no mapped faults within or adjacent to the project site, and the project site is not located within an Alquist-Priolo Zone.59 As detailed in the Preliminary Geotechnical Exploration prepared for the proposed project, the soil materials encountered within the project site generally consist of clayey soil and bedrock that are not susceptible to liquefaction. As detailed in the Preliminary Geotechnical Exploration completed for the proposed project, the soil and bedrock at the site generally exhibit moderate to high shrink/swell potential with variations in moisture content.
57 ENGEO. 2022a. Vallejo Properties – Vista Cove, Vallejo, California, Preliminary Geotechnical Exploration.

September 12. 58 Baseline Environmental Consulting. 2025. Peer Review of Preliminary Geotechnical Exploration, Vista Cove Planned Development Project, Vallejo, California. March 26. 59 California Department of Conservation, California Geologic Survey (DOC CGS). 2021. Earthquake Zones of Required Investigation. Website: https://maps.conservation.ca.gov/cgs/EQZApp/app/ (accessed March 5, 2025).

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -66 As detailed in the Preliminary Geotechnical Exploration prepared for the proposed project, geologic mapping shows a queried landslide area crossing through the site. Based on a review of published maps, interpretation of aerial photographs, and completion of subsurface exploration, six landslide areas were identified adjacent to or within the project site that have a relatively high likelihood of experiencing instability. The landslides at the site are classified as shallow soil creep/earthflows, shallow landslide deposits, and deep-seated bedrock landslides.

4.7.3 Impact Analysis
a. Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:
i. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. (No Impact, No New Impact)
Fault rupture is generally expected to occur along active fault traces that have exhibited signs of recent geological movement (i.e., within the last 11,000 years). Alquist-Priolo Earthquake Fault Zones delineate areas around active faults with potential surface fault rupture hazards that would require specific geological investigations prior to approval of certain kinds of development within the delineated area. There are no mapped faults within or adjacent to the project site, and the project site is not located within an Alquist-Priolo Zone.60 The nearest mapped fault to the project site is the Green Valley Fault, which is located approximately 5 miles northeast of the project site.

Therefore, the project would not directly or indirectly cause substantial adverse effects related to fault rupture, and there would be no impact. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
ii. Strong seismic ground shaking? (No Impact, No New Impact) The project site is in a seismically active area, where earthquakes have the potential to subject the project to strong seismic ground shaking. The intensity of ground shaking would depend on the characteristics of the fault, distance from the fault, the earthquake’s magnitude and duration, and site-specific geologic conditions.

The City requires projects to comply with the 2022 California Building Code (CBC) (Title 24, California Code of Regulations),61 which provides stringent construction requirements on projects in areas of high seismic risk based on numerous interrelated factors. It is acknowledged that seismic hazards cannot be completely eliminated even with implementation of advanced building practices.

However, the seismic design standards of the CBC are intended to prevent catastrophic structural 60 California Department of Conservation, California Geologic Survey (DOC CGS). 2021. Earthquake Zones of Required Investigation. Website: https://maps.conservation.ca.gov/cgs/EQZApp/app/ (accessed March 5, 2025). 61 Vallejo, City of. n.d.-c. Vallejo, California – Municipal Code, Title 12 – Buildings and Construction, Chapter

12.48.010 – Existing Building Code Adoption.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) failure in the most severe earthquakes currently anticipated. Therefore, the proposed project would not directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving seismic ground shaking, and there would be no impact. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. iii. Seismic-related ground failure, including liquefaction? (No Impact, No New Impact) Liquefaction. Soil liquefaction is a phenomenon primarily associated with saturated soil layers located close to the ground surface. During ground shaking, these soils lose strength and acquire “mobility” sufficient to permit both horizontal and vertical movements. The significant factors on which liquefaction potential of a soil deposit depends include, among others, soil type, relative soil density, intensity of earthquake, duration of ground shaking, and depth of ground water. Soils that are most susceptible to liquefaction are clean, loose, uniformly graded, saturated, fine-grained sands that lie relatively close to the ground surface. However, loose sands that contain a significant amount of fines (i.e., silt and clay) may also liquefy. As detailed in the Preliminary Geotechnical Exploration prepared for the proposed project, the soil materials encountered within the project site generally consist of clayey soil and bedrock that are not susceptible to liquefaction. Therefore, the project site would not be susceptible to liquefaction, and no impact would occur. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. iv. Landslides? (Less than Significant with Mitigation Incorporated, No New Impact) A landslide generally occurs on relatively steep slopes and/or on slopes underlain by weak materials.

Seismically induced landslides are triggered by earthquake ground shaking. The risk of this hazard is greatest in the late winter, when groundwater levels are highest and hillside colluvium is saturated.

As detailed in the Preliminary Geotechnical Exploration prepared for the proposed project, geologic mapping shows a queried landslide area crossing through the site. Based on a review of published maps, interpretation of aerial photographs, and completion of subsurface exploration, six landslide areas were identified adjacent to or within the project site that have a relatively high likelihood of experiencing instability. The landslides at the site are classified as shallow soil creep/earthflows, shallow landslide deposits, and deep-seated bedrock landslides. The Preliminary Geotechnical Exploration includes conceptual mitigation measures for each landslide area and recommends a design-level geotechnical review be completed prior to issuing the plans for construction.

Project Specific Mitigation Measure GEO-1 Design-Level Geotechnical Review. A licensed Geotechnical Engineer or their representative shall
be retained to perform a design‐level geotechnical
investigation once site development plans are final.

The design‐level geotechnical investigation shall
include further evaluation of potential geologic
hazards related to landslides, stability of graded
slopes, corrective grading for planned building sites,
and the presence of moderate to highly expansive
soil and bedrock. The design‐level investigation

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -68 findings shall be used to address all the
geotechnical concerns described in the Preliminary
Geotechnical Exploration and to develop detailed
recommendations for design and construction.

The recommendations of the Preliminary
Geotechnical Exploration and any
recommendations included in the required design‐
level geotechnical investigation for the project shall
be incorporated into all design and engineering
plans. At the end of construction, the Geotechnical
Engineer shall provide a letter regarding contractor
compliance with project plans and specifications
and with the recommendations of the Geotechnical
Investigation and any supplemental
recommendations issued during construction. The
letter shall be submitted for review to the City of
Vallejo Building Division and confirmed prior to
issuance of a certificate of occupancy.

Implementation of Project Specific Mitigation Measure GEO-1, which requires the project sponsor to incorporate all of the recommendations of the Geotechnical Investigation and any recommendations included in a design-level geotechnical investigation into the project development plans, would reduce the potential impacts related to landslides to a less than significant level. This is a standard measure applicable to projects located within areas that are subject to seismic activity and related hazard areas, to ensure that the most stringent building standards are implemented. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. b. Would the project result in substantial soil erosion or the loss of topsoil? (Less Than Significant Impact, No New Impact)
Topsoil is defined as the upper part of the soil profile that is relatively rich in humus and is technically known as the A-horizon of the soil profile.62 Grading and earthmoving during project construction has the potential to result in erosion and loss of topsoil. Exposed soils could be entrained in stormwater runoff and transported off the project site. However, this impact would be less than significant through compliance with the regulatory requirements detailed in Section 4.10, Hydrology and Water Quality, which include the preparation of a Stormwater Pollution Prevention Plan (SWPPP). Although designed primarily to protect stormwater quality, the SWPPP would incorporate Best Management Practices (BMPs) to minimize impacts related to erosion to a less than significant level. Additional details regarding the SWPPP are provided in Section 4.10, Hydrology and Water Quality of this Initial Study. No new impacts or substantially more severe 62 California State Mining and Geology Board. 2014. Surface Mining Reclamation Act Regulations. California Code of Regulations, Title 14, Division 2, Chapter 8, Subchapter 1.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
c. Would the project be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse? (Less than Significant with Mitigation Incorporated, No New Impact)
As discussed in Section 4.7.a, site soils would not be subject to liquefaction and impacts related to landslides would be reduced to a less than significant level with the implementation of Project Specific Mitigation Measure GEO-1.

Lateral Spreading. Lateral spreading is a form of horizontal displacement of soil toward an open channel or other “free” face, such as an excavation boundary. In a lateral spread failure, a layer of ground at the surface is carried on an underlying layer of liquefied material over a nearly flat surface toward a river channel or other bank. The lateral spreading hazard tends to mirror the liquefaction hazard for a site. Because the project site is not susceptible to liquefaction, the potential for seismically induced lateral spreading is low. Therefore, the project site would not be susceptible to lateral spreading, and no impact would occur.

Subsidence. Subsidence can result from the removal of subsurface water, resulting in either gradual depression or catastrophic collapse of the ground surface. As detailed in the Preliminary Geotechnical Exploration completed for the proposed project, no groundwater was encountered within the test pits, trench, and borings completed as part of the exploration. However, fluctuations in groundwater levels occur seasonally and over a period of years due to variations in precipitation, temperature, irrigation, and other factors. Therefore, dewatering may be required in isolated areas of the project site during construction. Construction-related dewatering would not be expected to result in subsidence or soil collapse as the dewatering activities would be temporary, localized, and affect only the uppermost water-bearing zone. Therefore, subsidence would not occur and there would be no impact.

Unstable Soils and Collapse. As detailed in the Preliminary Geotechnical Exploration completed for the proposed project, soils on site generally consist of colluvial soil overlaying mudstone bedrock interbedded with indurated sandstone, shale, siltstone, and claystone or colluvial deposits overlaying weak to very weak interbedded sandstone, siltstone, and mudstone. Colluvial deposits that include soft or compressible materials over bedrock have the potential for settlement due to building loads or engineered fill loads. To minimize settlement, the Preliminary Geotechnical Exploration recommends corrective grading measure including the removal of compressible materials down to a hard material/bedrock. Colluvial soil on steeper slopes is also subject to soil creep, which is the slow downslope movement of soil that occurs with the annual cycle of wetting and drying under the influence of gravity. To minimize soil creep, the Preliminary Geotechnical Exploration recommends benching through surficial soil during fill placement or designing drilled pier foundation systems to accommodate lateral loads from soil creep.

Due to the steep slopes at the project site, the Preliminary Geotechnical Exploration also includes corrective grading recommendations to ensure the stability of graded slopes, including removal of

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Implementation of Project Specific Mitigation Measure GEO-1, which requires the project sponsor to incorporate all of the recommendations of the Geotechnical Investigation and any recommendations included in a design-level geotechnical investigation into the project development plans, would reduce the potential impacts related to unstable soils and collapse to a less than significant level with mitigation. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
d. Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? (Less than Significant with Mitigation Incorporated, No New Impact) Expansive soils are characterized by the potential for shrinking and swelling as the moisture content of the soil decreases and increases, respectively. Shrink-swell potential is influenced by the amount and type of clay minerals present and can be measured by the percent change of the soil volume.

As detailed in the Preliminary Geotechnical Exploration completed for the proposed project, the soil and bedrock at the site generally exhibit moderate to high shrink/swell potential with variations in moisture content. The Preliminary Geotechnical Exploration includes preliminary earthwork, foundation, and retaining wall recommendations to prevent potential impacts related to expansive soil and recommends a design-level geotechnical review be completed prior to issuing the plans for construction.

Implementation of Project Specific Mitigation Measure GEO-1, which requires the project sponsor to incorporate all of the recommendations of the Geotechnical Investigation and any recommendations included in a design-level geotechnical investigation into the project development plans, would reduce the potential impacts related to expansive soil to a less than significant level with mitigation. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. e. Would the project have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water? (No Impact, No New Impact)
Development of the proposed project would not involve the use of septic tanks or alternative wastewater disposal systems. Therefore, the proposed project would have no impact related to septic tanks or alternative wastewater disposal systems. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) f. Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? (Less than Significant with Mitigation Incorporated, No New Impact) There are no known paleontological resources or unique geologic features within or near the project site. However, according to a search of the University of California Museum of Paleontology (UCMP) at the University of California, Berkeley, there are 296 known localities that have produced 1,699 specimens within Solano County.63 Therefore, the possibility of accidental discovery of paleontological resources during project construction cannot be discounted. Implementation of Project Specific Mitigation Measure GEO-2, described below, would reduce potential impacts to paleontological resources to a less than significant level. This is a standard accidental-discovery measure required of most construction projects that include soil excavation throughout the Bay Area and the State. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

Project Specific Mitigation Measure GEO-2 Discovery of Paleontological Resources. Should paleontological resources be encountered during
project subsurface construction activities, all
ground-disturbing activities within 25 feet shall be
redirected and a qualified paleontologist contacted
to assess the situation, consult with agencies as
appropriate, and make recommendations for the
treatment of the discovery. For purposes of this
mitigation, a “qualified paleontologist” shall be an
individual with the following qualifications: (1) a
graduate degree in paleontology or geology and/or
a person with a demonstrated publication record in
peer-reviewed paleontological journals; (2) at least
2 years of professional experience related to
paleontology; (3) proficiency in recognizing fossils in the field and determining their significance; (4)
expertise in local geology, stratigraphy, and
biostratigraphy; and (5) experience collecting
vertebrate fossils in the field. If the paleontological resources are found to be significant and project
activities cannot avoid them, measures shall be
implemented to ensure that the project does not
cause a substantial adverse change in the
significance of the paleontological resource.

Measures may include monitoring, recording the
fossil locality, data recovery and analysis, a final
report, and accessioning the fossil material and
technical report to a paleontological repository.

Upon completion of the assessment, a report
63 University of California Museum of Paleontology (UCMP). Databases. Website: https://ucmp.berkeley. edu/collections/databases/ (accessed March 5, 2025).

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recommendations shall be prepared and submitted
to the City of Vallejo for review. If paleontological
materials are recovered, this report also shall be
submitted to a paleontological repository, such as
the University of California Museum of
Paleontology, along with significant paleontological
materials. Public educational outreach may also be
appropriate.

The project sponsor shall inform its contractor(s) of
the sensitivity of the project site for paleontological resources and shall verify that the following
directive has been included in the project grading
plans:
“The subsurface of the construction site may
be sensitive for fossils. If fossils are
encountered during project subsurface
construction, all ground-disturbing activities
within 25 feet shall be redirected and a
qualified paleontologist contacted to assess
the situation, consult with agencies as
appropriate, and make recommendations for
the treatment of the discovery. Project
personnel shall not collect or move any
paleontological materials. Fossils can include
plants and animals, and such trace fossil
evidence of past life as tracks or plant
imprints. Ancient marine sediments may
contain invertebrate fossils such as snails,
clam and oyster shells, sponges, and
protozoa; and vertebrate fossils such as fish,
whale, and sea lion bones. Contractor
acknowledges and understands that
excavation or removal of paleontological
material is prohibited by law and constitutes a
misdemeanor under California Public
Resources Code, Section 5097.5.”

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4.8 GREENHOUSE GAS EMISSIONS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the
environment?
b. Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of
greenhouse gases?

4.8.1 Prior Environmental Analysis
Chapter 4.6 of the General Plan EIR analyzed impacts related to greenhouse gas (GHG) emissions associated with build out of the General Plan. The General Plan EIR determined that while implementation of the General Plan supports progress toward the long term-goals identified in Executive Order B-30-15 and Executive Order S-03-05, it cannot yet be demonstrated that the City will achieve GHG emissions reductions that are consistent with a 60 percent reduction below 1990 levels by the year 2040 based on existing technologies and currently adopted policies and programs.

The General Plan EIR prescribed Mitigation Measure GHG-1, which requires the City to update its Climate Action Plan (CAP) to address the GHG reduction goals of Executive Order B-30-15 for GHG sectors that the City has direct or indirect jurisdictional control over. However, the General Plan EIR determined that even with implementation of General Plan EIR Mitigation Measure GHG-1, GHG impacts would be significant and unavoidable.

In addition, the General Plan EIR evaluated consistency with the California Air Resources Board (CARB) Scoping Plan, Plan Bay Area, and the Vallejo CAP. The General Plan EIR found that while the General Plan would be consistent with the regional objectives of Plan Bay Area and the City’s CAP and the policies and programs in the General Plan would ensure substantial progress toward the long-term GHG reductions goals for 2050, additional State and federal measures are necessary to achieve the more aggressive targets established for 2050 in Executive Order S-03-05. Therefore, the General Plan EIR identified Mitigation Measure GHG-2, which requires implementation of General Plan EIR Mitigation Measure GHG-1. However, the General Plan EIR found that impacts would be significant and unavoidable, even with implementation of identified mitigation measures.

4.8.2 Background
GHGs are present in the atmosphere naturally, are released by natural sources, or are formed from secondary reactions taking place in the atmosphere. The gases that are widely seen as the principal contributors to human-induced global climate change are:
• Carbon dioxide (CO2);
• Methane (CH4);
• Nitrous oxide (N2O);
• Hydrofluorocarbons (HFCs);

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• Sulfur hexafluoride (SF6).

Over the last 200 years, humans have caused substantial quantities of GHGs to be released into the atmosphere. These extra emissions are increasing GHG concentrations in the atmosphere and enhancing the natural greenhouse effect, believed to be causing global warming. While man-made GHGs include naturally occurring GHGs such as CO2, methane, and N2O, some gases, like HFCs, PFCs, and SF6, are completely new to the atmosphere.

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

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

4.8.3 Impact Analysis
a. Would the project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? (Potentially Significant Impact, No New Impact) This section describes the proposed project’s construction- and operation-related GHG emissions and contribution to global climate change. The Air District did not address emission thresholds for construction in its CEQA Guidelines; however, the Air District encourages quantification and disclosure. The General Plan EIR included a quantitative analysis of GHG emissions associated with operational activities from build out of the General Plan. As the proposed project is consistent with the build out assumed in the General Plan EIR and the Addendum to the General Plan EIR for the 2023-2031 Housing Element Update64 (Housing Element Addendum), the proposed project’s anticipated GHG emissions associated with project operation were included in the GHG emissions analysis contained in the General Plan EIR. As such, the following section describes potential impacts associated with GHG emissions that could occur if the construction and operation of the proposed project would result in a new significant or substantially greater impact than the impacts identified in the City’s General Plan EIR and Housing Element Addendum.

Construction GHG Emissions. Construction activities associated with the proposed project would produce combustion emissions from various sources. During construction, GHGs would be emitted 64 Vallejo, City of. 2024. Addendum to the General Plan EIR 2023-2031 Housing Element Update. State Clearinghouse No. 2014112035. December 6.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) through the operation of construction equipment and from worker and builder supply vendor vehicles, which typically use fossil-based fuels to operate. The combustion of fossil-based fuels creates GHGs such as CO2, CH4, and N2O. Furthermore, CH4 is emitted during the fueling of heavy equipment. Exhaust emissions from on-site construction activities would vary daily as construction activity levels change. GHG emissions generated during construction of the proposed project would be short term in nature, lasting only for the duration of the construction period, and would not represent a long-term source of GHG emissions.

As discussed in Section 4.3, Air Quality, construction emissions were estimated for the proposed project using CalEEMod, consistent with the Air District’s recommendations. As included in the CalEEMod modeling, construction of the proposed project is anticipated to begin in June 2026 and would occur over an approximately 1-year period. It is anticipated that 58,700 cubic yards of soil would be cut, and 59,300 cubic yards would be used for fill, resulting in a total soil import of 600 cubic yards, which was included in CalEEMod. This analysis utilizes the default construction equipment list and assumes use of Tier 2 construction equipment for all phases of project construction. CalEEMod output sheets are included in Appendix A.

Using CalEEMod, it is estimated that the construction of the proposed project would generate approximately 306.0 metric tons (MT) CO2e during construction of the project. Implementation of the Air District’s Basic BMPs, as required by General Plan EIR Mitigation Measure AQ-2b.1, would reduce GHG emissions by reducing the amount of construction vehicle idling and by requiring the use of properly maintained equipment. This measure is implemented by the City and the Air District to ensure that GHG emissions would be less than significant. In addition, construction activities would be minimal and GHG emissions generated during construction of the proposed project would be short term in nature, lasting only for the duration of the construction period. The General Plan EIR did not quantify construction-related GHG emissions; however, since GHG emissions associated with construction activities would not represent a long-term source of GHG emissions and would cease once construction is completed, project construction impacts associated with GHG emissions would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

Operational GHG Emissions. Long-term GHG emissions associated with the proposed project would typically be generated from mobile sources (e.g., vehicle trips), area sources (e.g., maintenance activities and landscaping), indirect emissions from sources associated with energy consumption, waste sources (land filling and waste disposal), and water sources (water supply and conveyance, treatment, and distribution). Mobile-source GHG emissions would include project-generated vehicle trips to and from the project site. Area-source emissions would be associated with activities such as landscaping and maintenance on the project site. Energy source emissions would be generated at off-site utility providers from increased electricity demand generated by the proposed project.

Waste source emissions generated by the proposed project include energy generated by transporting and managing project generated waste. In addition, water source emissions associated with the proposed project are generated by water supply and conveyance, water treatment, water distribution, and wastewater treatment.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -76 The General Plan EIR found that operational GHG emissions associated with development facilitated by the General Plan would result in 2.6 MT CO2e per service population per year, above the planlevel efficiency target of 2.5 MT CO2e per service population per year identified in the General Plan EIR, which was found to be a significant and unavoidable impact. As such, for the purpose of this analysis, the proposed project is compared to the GHG efficiency target of 2.5 MT CO2e per service population.

Consistent with the General Plan EIR, GHG emissions were estimated using CalEEMod. Table 4.8.A shows the calculated GHG emissions for the proposed project. As discussed in Section 4.3, Air Quality, trip generation rates for the project were based on the project’s trip generation estimates of approximately 481 average daily trips. In addition, the proposed project would have a standby diesel backup generator. Therefore, this analysis conservatively assumes that there would be a 500- horsepower diesel generator that would run up to 50 hours annually. Where project-specific data were not available, default assumptions (e.g., electricity usage, water usage, and solid waste generation) from CalEEMod were used to estimate project emissions. CalEEMod output sheets are included in Appendix A.

Table 4.8.A: Project Greenhouse Gas Emissions
Emissions Source Category Operational Emissions (metric tons per year) CO2 CH4 N2O CO2e
Mobile 664.0 <0.1 <0.1 675.0
Area 1.5 <0.1 <0.1 1.5
Energy 119.0 <0.1 <0.1 119.6
Water 2.7 0.1 <0.1 4.6
Waste 3.1 0.3 0.0 10.8
Stationary 9.5 <0.1 <0.1 9.6
Total Operational Emissions 811.9
Total Annual Service Population Emissions (Metric Tons/Year/Service Population) 5.7 Source: Compiled by LSA (September 2025).

CH4 = methane
CO2 = carbon dioxide
CO2e = carbon dioxide equivalents
N2O = nitrous oxide
As shown in Table 4.8.A, the proposed project would generate approximately 811.9 metric tons of CO2e. As discussed in Section 4.14, Population and Housing, the proposed project would result in approximately 143 residents on the project site. Therefore, the total service population (residents plus employees) would be 143 people. As such, the proposed project’s GHG emissions would result in a GHG efficiency of 5.7 metric tons CO2e per service population, which would exceed the planlevel efficiency target of 2.5 MT CO2e per service population per year identified in the General Plan EIR. As such, similar to build out under the General Plan, the proposed project would not achieve the GHG efficiency metric for the year 2040.

The project site was identified as a housing opportunity site in the General Plan EIR. As discussed in the Project Description, the General Plan designates the project site as R-MH and R-SF. The maximum permitted residential density in the R-MH designation is 25 dwelling units per acre, and

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) nine dwelling units per acre in the R-SF designation; however, in single-family areas where accessory dwelling units are allowed, maximum permitted residential density is 12 dwelling units per acre. To facilitate development of the project as proposed, the project site would be rezoned as PD and would result in 51 new residential units. As such, the proposed project would introduce fewer residential uses and a lower density than previously assumed in the General Plan EIR. Therefore, while the proposed project’s GHG emissions per service population are higher than the service population emissions identified in the General Plan EIR, it is assumed that the proposed project would result in fewer total project operational emissions than were previously assumed for the project site in the General Plan EIR.

Further, the Housing Element sites inventory identifies 51 dwelling units on the project site. The Housing Element Addendum did not quantify GHG emissions associated with the Housing Element Update but found that GHG emissions associated with the Housing Element would be significant and unavoidable but would not exceed the significant and unavoidable impacts evaluated in the General Plan EIR. Therefore, since the proposed project would be consistent with the uses assumed in the Housing Element Addendum, the proposed project would contribute to the significant and unavoidable impacts identified in the General Plan EIR and Housing Element Addendum. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR and Housing Element Addendum.
b. Would the project conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases? (Potentially Significant Impact, No New Impact) Applicable plans adopted for the purpose of reducing GHG emissions include the 2022 Scoping Plan, Plan Bay Area, and the City’s CAP. As such, the proposed project was evaluated for consistency with those plans to demonstrate whether the proposed project would conflict with any applicable plan, policy, or regulation of an agency adopted for the purpose of reducing the GHG emissions.

Scoping Plan. The following discussion evaluates the proposed project according to the goals of the 2022 Scoping Plan, Executive Order (EO) B-30-15, Senate Bill (SB) 32, and Assembly Bill (AB) 197.

EO B-30-15 added the immediate target of reducing GHG emissions to 40 percent below 1990 levels by 2030. The CARB released a second update to the Scoping Plan, the 2017 Scoping Plan, to reflect the 2030 target set by EO B-30-15 and codified by SB 32. SB 32 affirms the importance of addressing climate change by codifying into statute the GHG emissions reductions target of at least 40 percent below 1990 levels by 2030 contained in EO B-30-15. SB 32 builds on AB 32 and keeps the State on the path toward achieving the 2050 objective of reducing emissions to 80 percent below 1990 levels. The companion bill to SB 32, AB 197 provides additional direction to the CARB related to the adoption of strategies to reduce GHG emissions. Additional direction in AB 197 intended to provide easier public access to air emissions data that are collected by the CARB was posted in December 2016.

The 2022 Scoping Plan assesses progress toward the statutory 2030 target while laying out a path to achieving carbon neutrality no later than 2045. The 2022 Scoping Plan focuses on outcomes needed to achieve carbon neutrality by assessing paths for clean technology, energy deployment, natural

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

As identified above, the 2022 Scoping Plan contains GHG reduction measures that work towards reducing GHG emissions, consistent with the targets set by EO B-30-15 and codified by SB 32 and AB 197. The measures applicable to the proposed project include energy efficiency measures, water conservation and efficiency measures, and transportation and motor vehicle measures, as qualitatively discussed below.

Energy Measures. Energy-efficient measures are intended to maximize energy efficiency building and appliance standards, pursue additional efficiency efforts including new technologies and new policy and implementation mechanisms, and pursue comparable investment in energy efficiency from all retail providers of electricity in California. In addition, these measures are designed to expand the use of green building practices to reduce the carbon footprint of California’s new and existing inventory of buildings. The proposed project would comply with current California Energy Code and CALGreen standards. However, the proposed project would not be all-electric and would include natural gas. The elimination of natural gas in new development would help projects implement their “fair share” of achieving long-term 2045 carbon neutrality consistent State goals. As such, if a project does not utilize natural gas, a lead agency can conclude that it would be consistent with achieving the 2045 neutrality goal and will not have a cumulative considerable impact on climate change. Therefore, since the proposed project would include natural gas, and the proposed project would not be consistent with the applicable energy measures.

Water Conservation and Efficiency Measures. Water conservation and efficiency measures are intended to continue efficiency programs and use cleaner energy sources to move and treat water.

Increasing the efficiency of water transport and reducing water use would reduce GHG emissions. As identified above, the proposed project would comply with current CALGreen Code standards, which include a variety of different measures, including reduction of wastewater and water use. In addition, the proposed project would be required to comply with the California Model Water Efficient Landscape Ordinance. Therefore, the proposed project would comply with applicable water conservation and efficiency measures.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Transportation and Motor Vehicle Measures. The goal of transportation and motor vehicle measures is to develop regional GHG emissions reduction targets for passenger vehicles. Specific regional emission targets for transportation emissions would not directly apply to the proposed project. The second phase of Pavley standards will reduce GHG emissions from new cars by 34 percent from 2016 levels by 2025, resulting in a 3 percent decrease in average vehicle emissions for all vehicles by 2020. The majority of vehicles traveling to the project site would comply with the Pavley II (LEV III) Advanced Clean Cars Program. Therefore, the proposed project would comply with applicable transportation and motor vehicle measures.

The proposed project would result in the subdivision of the 20.13-acre site, of which approximately 10 acres would be developed, while the remaining acreage would not be developed and would remain as private open space. The residential portion of the proposed project would include 51 residential lots, open space, and related infrastructure improvements. The project site is located within walking or bicycling distance from the surrounding adjacent residential, recreational, and public and semi-public uses, as described in Section 2.1.4, Surrounding Land Uses. Additionally, the project site is served by SolTrans Routes 3 and 8, with the transit stops located approximately 0.5 mile to the west along Glen Cove Parkway. The Amtrak station in Vallejo is approximately 4 miles northwest of the project site, and the Vallejo Ferry Terminal, which offers ferry service between Vallejo and San Francisco, is approximately 3.5 miles northwest of the project site. Therefore, the project would support the ability of residents and visitors to use alternative modes of transportation.

In addition, the 2022 Scoping Plan includes key project attributes that reduce operational GHG emissions in Appendix D, Local Actions,65 of the 2022 Scoping Plan. A summary of the proposed project’s consistency with the 2022 Scoping Plan’s key project attributes identified in Appendix D of the 2022 Scoping Plan is shown in Table 4.8.B.

Plan Bay Area. As described above, Plan Bay Area 2050 is a State-mandated, integrated longrange transportation and land use plan. Plan Bay Area 2050 includes 11 goals and 35 performance targets covering four broad areas: housing, economic, transportation, and environmental. These targets enable the plan to be evaluated by its performance in areas identified as key regional concerns, including equitable access, economic vitality, and transportation system effectiveness. Table 4.8.C includes an evaluation of the proposed project’s consistency with Plan Bay Area 2050 goals and performance targets. 65 California Air Resources Board (CARB). 2022. 2022 Scoping Plan, Appendix D Local Actions. November.

Website: https://ww2.arb.ca.gov/sites/default/files/2022-11/2022-sp-appendix-d-local-actions.pdf (accessed February 2024).

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -80 Table 4.8.B: Project Consistency with 2022 Scoping Plan Key Project Attributes Priority Areas Key Project Attribute Project Consistency Transportation
Electrification
Provides EV charging
infrastructure that, at minimum,
meets the most ambitious
voluntary standard in the
California Green Building
Standards Code at the time of
project approval.

Consistent. The proposed project would provide electric vehicle charging capabilities that meet the requirements of the latest version of CALGreen. As such, the proposed project would be consistent with this key project attribute.

VMT Reduction Is located on infill sites that are
surrounded by existing urban
uses and reuses or redevelops
previously undeveloped or
underutilized land that is
presently served by existing
utilities and essential public
services (e.g., transit, streets,
water, sewer).

Consistent. The project site is located in an urban area in Vallejo and is generally surrounded by residential, recreational, and open space uses. In addition, the project site is presently served by existing utilities and essential public services (e.g., transit, streets, water, sewer). The proposed project would be
consistent with this key project attribute.

Does not result in the loss or
conversion of natural and
working lands.

Consistent. The City of Vallejo General Plan 2040 designates the project site as Mix of Housing Types (R-MH) and Primarily Single Family (R-SF). The project site consists of undeveloped grassland with scattered mature trees with no existing development or improvements. The project site is classified as “Grazing Land” and “Urban and Built-Up Land” by the California Department of Conservation (DOC). The proposed project does not consist of natural or working lands; therefore, the proposed project would be consistent with this key project attribute.

Consists of transit-supportive
densities (minimum of 20
residential dwelling units per
acre) or is in proximity to
existing transit stops (within

0.50 mile) or satisfies more
detailed and stringent criteria
specified in the region’s SCS.

Consistent. The proposed project would result in the
development of a residential subdivision on the project site. The proposed project would result in the subdivision of the 20.13- acre site, of which approximately 10 acres would be developed, while the remaining acreage would remain undeveloped as private hillside area and open space. The residential portion of the proposed project would include 51 residential lots, open space, and related infrastructure improvements. The project site is located within walking or bicycling distance from the surrounding residential, recreational, and public and semipublic uses. Additionally, the project site is served by SolTrans Routes 3 and 8, with the transit stops located approximately 0.5 mile to the west along Glen Cove Parkway. The Amtrak station in Vallejo is approximately 4 miles northwest of the project site, and the Vallejo Ferry Terminal, which offers ferry service between Vallejo and San Francisco, is approximately 3.5 miles northwest of the project site. Therefore, the project would support the ability of residents and visitors to use alternative modes of transportation, consistent with the intent of this key attribute.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Table 4.8.B: Project Consistency with 2022 Scoping Plan Key Project Attributes Priority Areas Key Project Attribute Project Consistency Reduces parking requirements
by: eliminating parking
requirements or including
maximum allowable parking
ratios (i.e., the ratio of parking
spaces to residential units or
square feet); or providing
residential parking supply at a
ratio of less than one parking
space per dwelling unit; or for
multifamily residential
development, requiring parking
costs to be unbundled from
costs to rent or own a
residential unit.

Consistent. The proposed project would provide 102 covered garage spaces (2 per unit), 102 driveway stalls (2 per unit), 24 on-street stalls, and 1 mailbox parking stall, for a total of 229 parking spaces. However, as discussed above, the project would support the ability of residents and visitors to use alternative modes of transportation, consistent with the intent of this key attribute.

At least 20 percent of units
included are affordable to
lower-income residents.

Not Consistent. The proposed project would not include
affordable units.

Results in no net loss of existing
affordable units
.

Consistent. The proposed project would not result in a net loss of existing affordable units. The proposed project would provide 51 dwelling units to comply with the Housing Element sites inventory which identifies 51 dwelling units on the project site and the project would be consistent with this key project attribute.

Building
Decarbonization
Uses all-electric appliances
without any natural gas
connections and does not use
propane or other fossil fuels for
space heating, water heating, or
indoor cooking
Not Consistent. The proposed project would not be all-electric.

Source: Compiled by LSA (September 2025).

CALGreen Code = California Green Building Standards Code EV = electric vehicle
GHG = greenhouse gas
SB = Senate Bill
SCS = Sustainable Communities Strategy
TDM = Transportation Demand Management
VMT = vehicle miles traveled

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Housing Strategies
Protect and Preserve
Affordable Housing
H1. Further strengthen renter protections
beyond state law. Building upon recent
tenant protection laws, limit annual rent
increases to the rate of inflation, while
exempting units less than 10 years old.

Not Applicable. This is a community policy based
goal; therefore, this measure would not apply to
the project.

H2. Preserve existing affordable housing.

Acquire homes currently affordable to low
and middle-income residents for
preservation as permanently deedrestricted affordable housing.

Not Applicable. The project site does not include
any existing affordable housing.

Spur Housing
Production for
Residents of All
Income Levels
H3. Allow a greater mix of housing
densities and types in Growth
Geographies. Allow a variety of housing
types at a range of densities to be built in
Priority Development Areas, select TransitRich Areas and select High-Resource Areas.

Consistent. The proposed project would result in
the subdivision of the 20.13-acre site, of which
approximately 10 acres would be developed, while
the remaining acreage would remain as private
open space. The residential portion of the
proposed project would include 51 residential lots,
open space, and related infrastructure
improvements. The project site is located within
walking or bicycling distance from the surrounding
residential, recreational, and public and semipublic uses. Additionally, the project site is served by SolTrans Routes 3 and 8, with the transit stops
located approximately 0.5 mile to the west along
Glen Cove Parkway. The Amtrak station in Vallejo
is approximately 4 miles northwest of the project
site, and the Vallejo Ferry Terminal, which offers
ferry service between Vallejo and San Francisco, is
approximately 3.5 miles northwest of the project
site. Therefore, the project would support the
ability of residents and visitors to use alternative
modes of transportation. As such, the proposed
project would not conflict with the Air District’s
initiatives to increase the use of alternative means
of transportation, consistent with the intent of
this measure.

H4. Build adequate affordable housing to
ensure homes for all. Construct enough
deed-restricted affordable homes to fill the
existing gap in housing for the unhoused
community and to meet the needs of lowincome households.

Not Consistent. The proposed project would not
include affordable units; however, the proposed
project would help to address the California
housing shortage and would increase the number
of residences available to bay area residents.

Through increasing housing opportunities, the
proposed project would be consistent with State
and regional goals to advance the availability of
fair housing.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Table 4.8.C: Project Consistency with Plan Bay Area 2050 Goal Target Project Consistency
H5. Integrate affordable housing into all
major housing projects. Require a baseline
of 10-20% of new market-rate housing
developments of five units or more to be
affordable to low-income households.

Not Consistent. As discussed above, the proposed
project would not include affordable units;
however, the proposed project would help to
address the California housing shortage and would
increase the number of residences available to bay
area residents. Through increasing housing
opportunities, the proposed project would be
consistent with State and regional goals to
advance the availability of fair housing.

H6. Transform aging malls and office parks
into neighborhoods. Permit and promote
the reuse of shopping malls and office parks
with limited commercial viability as
neighborhoods with housing for residents
at all income levels.

Not Applicable. The project site does not include
an existing mall or office parks.

Create Inclusive
Communities
H7. Provide targeted mortgage, rental and
small business assistance to Equity Priority
Communities. Provide assistance to lowincome communities and communities of color to address the legacy of exclusion and
predatory lending, while helping to grow
locally owned businesses.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

H8. Accelerate reuse of public and
community-owned land for mixed-income
housing and essential services. Help public
agencies, community land trusts and other
non-profit landowners accelerate the
development of mixed-income affordable
housing.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

Economic Strategies
Improve Economic
Mobility
EC1. Implement a statewide universal
basic income. Provide an average $500 per
month payment to all Bay Area households
to improve family stability, promote
economic mobility and increase consumer
spending.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

EC2. Expand job training and incubator
programs. Fund assistance programs for
establishing new businesses, as well as job
training programs, primarily in historically
disinvested communities.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

EC3. Invest in high-speed internet in
underserved low-income communities.

Provide direct subsidies and construct
public infrastructure to ensure all
communities have affordable access to
high-speed internet.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

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Shift the Location of
Jobs
EC4. Allow greater commercial densities in
Growth Geographies. Allow greater
densities for new commercial development
in select Priority Development Areas and
Transit-Rich Areas to encourage more jobs
to locate near public transit.

Not Applicable. The proposed project would not
include new commercial development; therefore,
this measure would not be applicable to the
project.

EC5. Provide incentives to employers to
shift jobs to housing-rich areas well served
by transit. Provide subsidies to encourage
employers to relocate off ices to housingrich areas near regional rail stations.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

EC6. Retain and invest in key industrial
lands. Implement local land use policies to
protect key industrial lands, identified as
Priority Production Areas, while funding key
infrastructure improvements in these areas.

Not Applicable. The proposed project would not
include new industrial development; therefore,
this measure would not be applicable to the
project.

Transportation Strategies
Maintain and
Optimize the Existing
System
T1. Restore, operate and maintain the
existing system. Commit to operate and
maintain the Bay Area’s roads and transit
infrastructure while reversing pandemicrelated cuts to total transit service hours.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

T2. Support community-led transportation
enhancements in Equity Priority
Communities. Provide direct funding to
historically marginalized communities for
locally identified transportation needs.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

T3. Enable a seamless mobility experience.

Eliminate barriers to multi-operator transit
trips by streamlining fare payment and trip
planning while requiring schedule
coordination at timed transfer hubs.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

T4. Reform regional transit fare policy.

Streamline fare payment and replace
existing operator- specific discounted fare
programs with an integrated fare structure
across all transit operators.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

T5. Implement per-mile tolling on
congested freeways with transit
alternatives. Apply a per-mile charge on
auto travel on select congested freeway
corridors where transit alternatives exist,
with discounts for carpoolers, low-income
residents, and off-peak travel; and reinvest
excess revenues into transit alternatives in
the corridor.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

T6. Improve interchanges and address
highway bottlenecks. Rebuild interchanges
and widen key highway bottlenecks to
achieve short- to medium-term congestion
relief.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

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T7. Advance other regional programs and
local priorities. Fund regional programs like
motorist aid and 511 while supporting local
transportation investments on arterials and
local streets.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

Create Healthy and
Safe Streets
T8. Build a Complete Streets network.

Enhance streets to promote walking, biking
and other micro-mobility through sidewalk
improvements, car-free slow streets, and
10,000 miles of bike lanes or multi-use
paths.

Consistent. The proposed project would result in
the subdivision of the 20.13-acre site, of which
approximately 10 acres would be developed, while
the remaining acreage would remain
undeveloped. The residential portion of the
proposed project would include 51 residential lots,
open space, and related infrastructure
improvements. The project site is located within
walking or bicycling distance from the surrounding
residential, recreational, and public and semipublic uses. Additionally, the project site is served by SolTrans Routes 3 and 8, with the transit stops
located approximately 0.5 mile to the west along
Glen Cove Parkway. The Amtrak station in Vallejo
is approximately 4 miles northwest of the project
site, and the Vallejo Ferry Terminal, which offers
ferry service between Vallejo and San Francisco, is
approximately 3.5 miles northwest of the project
site. Therefore, the project would support the
ability of residents and visitors to use alternative
modes of transportation. As such, the proposed
project would not conflict with the Air District’s
initiatives to increase the use of alternative means
of transportation, consistent with the intent of
this measure.

T9. Advance regional Vision Zero policy
through street design and reduced speeds.

Reduce speed limits to between 20 and 35
miles per hour on local streets and 55 miles
per hour on freeways, relying on design
elements on local streets and automated
speed enforcement on freeways.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

Build a NextGeneration Transit
Network
T10. Enhance local transit frequency,
capacity and reliability. Improve the quality
and availability of local bus and light rail
service, with new bus rapid transit lines,
South Bay light rail extensions, and
frequency increases focused in lowerincome communities.

Not Applicable. This strategy is not applicable as
the proposed project would consist of a residential
development.

T11. Expand and modernize the regional
rail network. Better connect communities
while increasing frequencies by advancing
the Link21 new transbay rail crossing, BART
to Silicon Valley Phase 2, Valley Link,
Caltrain Downtown Rail Extension and
Caltrain/High-Speed Rail grade separations,
among other projects.

Not Applicable. This strategy is not applicable as
the proposed project would consist of a residential
development.

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T12. Build an integrated regional express
lanes and express bus network. Complete
the buildout of the regional express lanes
network to provide uncongested freeway
lanes for new and improved express bus
services, carpools and toll-paying solo
drivers.

Not Applicable. This strategy is not applicable as
the proposed project would consist of a residential
development.

Environmental Strategies
Reduce Risks From
Hazards
EN1. Adapt to sea level rise. Protect
shoreline communities affected by sea level
rise, prioritizing low-cost, high-benefit
solutions and providing additional support
to vulnerable populations.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

EN2. Provide means-based financial
support to retrofit existing residential
buildings. Adopt building ordinances and
incentivize retrofits to existing buildings to
meet higher seismic, wildfire, water and
energy standards, providing means-based
subsidies to off-set associated costs.

Not Applicable. This strategy is not applicable as
the proposed project would not consist of a
building retrofit.

EN3. Fund energy upgrades to enable
carbon neutrality in all existing commercial
and
public buildings. Support electrification and
resilient power system upgrades in all
public
and commercial buildings.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

Expand Access to
Parks and Open
Space
EN4. Maintain urban growth boundaries.

Using urban growth boundaries and other
existing environmental protections, focus
new development within the existing urban
footprint or areas otherwise suitable for
growth, as established by local jurisdictions.

Consistent. The proposed project would develop a
residential development with undeveloped open
space on a project site generally surrounded by
single-family residential neighborhoods.

EN5. Protect and manage high-value
conservation lands. Provide strategic
matching funds to help conserve and
maintain high-priority natural and
agricultural lands, including but not limited
to, Priority Conservation Areas and
wildland-urban interface areas.

Not Applicable. This is a community policy based
goal; therefore, this measure would not be
applicable to the project.

EN6. Modernize and expand parks, trails
and recreation facilities. Invest in quality
parks, trails and open spaces that provide
inclusive recreation opportunities for
people of all backgrounds, abilities and ages
to enjoy.

Not Applicable. This strategy is not applicable as
the proposed project would consist of a residential
development. However, 9.74 acres of the
proposed project would remain undeveloped
open space. The project site would also include

3.55 acres of common area open space that would
include two bioretention areas totaling 7,617
square feet, walkways, a loop walk around a
flexible use turf area, and a vista overlook for
residents.

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Reduce Climate
Emissions
EN7. Expand commute trip reduction
programs at major employers. Set a
sustainable commute target for major
employers as part of an expanded Bay Area
Commuter Benefits Program, with
employers responsible for funding
incentives and disincentives to shift auto
commuters to any combination of
telecommuting, transit, walking and/or
bicycling.

Not Applicable. This strategy is not applicable as
the proposed project would consist of a residential
development.

EN8. Expand clean vehicle initiatives.

Expand investments in clean vehicles,
including more fuel-efficient vehicles and
electric vehicle subsidies and chargers.

Consistent . The proposed project would provide
electric vehicle charging capabilities that meet the
requirements of the latest version of the
CALGreen. As such, the proposed project would be
consistent with this measure.

EN9. Expand transportation demand
management initiatives. Expand
investments in programs like vanpools,
bikeshare, carshare and parking fees to
discourage solo driving.

Consistent. As discussed above, the proposed
project would result in the subdivision of the

20.13-acre site, of which approximately 10 acres
would be developed, while the remaining acreage
would remain undeveloped. The residential
portion of the proposed project would include 51
residential lots, open space, and related
infrastructure improvements. The project site is
located within walking or bicycling distance from
the surrounding residential, recreational, and
public and semi-public uses. Additionally, the
project site is served by SolTrans Routes 3 and 8,
with the transit stops located approximately 0.5
mile to the west along Glen Cove Parkway. The
Amtrak station in Vallejo is approximately 4 miles
northwest of the project site, and the Vallejo Ferry
Terminal, which offers ferry service between
Vallejo and San Francisco, is approximately 3.5
miles northwest of the project site. Therefore, the
project would support the ability of residents and
visitors to use alternative modes of
transportation. As such, the proposed project
would not conflict with the Air District’s initiatives
to increase the use of alternative means of
transportation, consistent with the intent of this
measure.

Sources: Metropolitan Transportation Commission and Association of Bay Area Governments (2021); LSA (September 2025).

CALGreen Code = California Green Building Standards Code Vallejo Climate Action Plan. As discussed above, the City’s CAP identifies emission reduction goals to reduce GHG emissions in the city by 15 percent below the 2005 emission levels by 2020, consistent with AB 32. The proposed project would not be operational until post-2020; therefore, because the City’s CAP was prepared based on the 2020 GHG targets, which are now superseded by the 2030 GHG targets established in SB 32, the City’s CAP would not apply for streamlining. However, the CAP sets forth goals, measures, and actions to achieve emission

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• E-2. Building Standards: Require all new development to meet the minimum California Title 24 and California Green Building Standards Code requirements, as amended, and encourage new development to exceed the minimum requirements.
• E-4. Cool Roofs and Pavements. Increase tree planting and the use of cool roofs and cool pavement materials to reduce the urban heat island effect and corresponding energy consumption. Implement tree replacement policy for projects where tree removal is necessary.
• TDM-2. Mixed-Use, Higher-Density, Transit-Oriented Development. Promote mixed-use, higher-density development near transit nodes.
• TDM-3. Bicycle and Pedestrian Travel. Expand and link the network of pedestrian and bicycle paths and facilities through preparation of a Bicycle and Pedestrian Master Plan, with the goal of increasing the bicycle and pedestrian mode share 20 percent by 2035. • TDM-8. Jobs/Housing Balance. Plan for an improved jobs/housing balance in order to reduce the need for long-distance travel from residences to places of work. • OT-1. Efficient and Alternative Fuel Vehicles. Support the expanded use of efficient and alternative fuel vehicles.
• OT-4. Zero Emission Vehicle Stations. Provide electric vehicle charging stations. • W-2. Development Standards for Water Conservation. Require water conservation in all new buildings and landscapes.
• W-3. Recycling and Composting Efforts. Support waste diversion through composting and recycling programs.
• W-4. Development Standards for Recycling and Composting. Require waste diversion and use of recycled materials in new development.
• OR-2. Construction Equipment. Reduce emissions from heavy-duty construction equipment by limiting idling and utilizing cleaner fuels, equipment, and vehicles.

The proposed project would result in the subdivision of the 20.13-acre site, of which approximately 10 acres would be developed, while the remaining portion of the project site would remain undeveloped. As demonstrated in Section 4.17, Transportation, the proposed

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) project is not expected to result in a significant increase in the generation of vehicle trips or VMT. Additionally, the proposed project would provide electric vehicle charging capabilities that meet the requirements of the latest version of CALGreen as part of the final project designs. The proposed project would also be required to comply with the latest Title 24 standards, regarding energy conservation and green building standards, reduction of wastewater and water use, and waste reduction. In addition, the proposed project would include an 8-acre parcel that would remain private open space and the residential portion of the project site would provide 3.55 acres of common open space, consistent with the urban cooling measure of the CAP. As such, the proposed project would be consistent with applicable CAP measures. In addition, the idling times for construction vehicles would be restricted to 5 minutes or less and construction workers would be required to shut off idle equipment, as required by General Plan EIR Mitigation Measure AQ 2b.1 as detailed in Section 4.3, Air Quality.

Conclusion. As described above, the proposed project would generally be consistent with the 2022 Scoping Plan, Plan Bay Area 2050, and the City’s CAP. The proposed project would comply with the majority of regulations adopted for the purpose of reducing GHG emissions. Although the proposed project would not install fewer on-site parking spaces than required by code, the proposed project would support the ability of residents and visitors to use alternative modes of transportation. In addition, as discussed above, the elimination of natural gas in new development would help projects implement their “fair share” of achieving long-term 2045 carbon neutrality consistent with State goals. Therefore, since the proposed project would include natural gas, it would not be considered consistent with the long-term State GHG reduction goals and emission targets required in AB 32, SB 32, EO B-30-15, EO B-48-18, and AB 1279.

As discussed above, the General Plan EIR found that while the General Plan would be consistent with the regional objectives of Plan Bay Area and the City’s CAP and the policies and programs in the General Plan would ensure substantial progress toward the long-term GHG reductions goals for 2050, additional State and federal measures are necessary to achieve the more aggressive targets established for 2050 in EO S-03-05. The General Plan EIR concluded that impacts would be significant and unavoidable. Therefore, similar to the findings of the General Plan EIR and Housing Element Addendum, the proposed project would conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of GHG emissions. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR and Housing Element Addendum. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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4.9 HAZARDS AND HAZARDOUS MATERIALS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Create a significant hazard to the public or the
environment through the routine transport, use, or
disposal of hazardous materials?
b. Create a significant hazard to the public or the
environment through reasonably foreseeable upset
and accident conditions involving the release of
hazardous materials into the environment?
c. Emit hazardous emissions or handle hazardous or
acutely hazardous materials, substances, or waste
within one-quarter mile of an existing or proposed
school?
d. Be located on a site which is included on a list of
hazardous materials sites compiled pursuant to
Government Code Section 65962.5 and, as a result,
would it create a significant hazard to the public or the environment?
e. For a project located within an airport land use plan or, where such a plan has not been adopted, within 2 miles
of a public airport or public use airport, would the
project result in a safety hazard or excessive noise for people residing or working in the project area?
f. Impair implementation of or physically interfere with an adopted emergency response plan or emergency
evacuation plan?
g. Expose people or structures, either directly or
indirectly, to a significant risk of loss, injury or death involving wildland fires?

4.9.1 Prior Environmental Analysis
Chapter 4.7 of the General Plan EIR analyzed impacts related to hazards and hazardous materials associated with build out of the General Plan and determined that build out of the General Plan would result in less than significant impacts related to hazards and hazardous materials due to compliance with existing regulatory requirements including, but not limited to, the Hazardous Materials Transportation Act, the Resource Conservation and Recovery Act, the California Hazardous Materials Management Act, the California Health and Safety Code, California Code of Regulations, California Division of Occupational Safety and Health (Cal/OSHA) regulations, and other regulatory programs overseen by the Regional Water Quality Control Board, Department of Toxic Substances Control, and Solano County Department of Environmental Management. No mitigation measures were prescribed. However, the General Plan includes the following goals, policies, and actions related to hazards and hazardous materials which would be applicable to the proposed project:
• Goal NBE-5: Hazard Protection: Protect life and property from natural and human-made hazards.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) ○ Policy NBE-5.3: Health and Safety Codes. Enforce development regulations and building code requirements to protect residents, businesses, and employees from flooding, liquefaction, earthquakes, fires, and other hazards.
■ Action NBE-5.4C: Continue to use the development review process to ensure that development is planned and constructed to resist the encroachment of uncontrolled fire.
○ Policy NBE-5.10: Site Safety. Ensure that affected soil, groundwater, or buildings will not have the potential to adversely affect the environment or the health and safety of site occupants.
■ Action NBE-5.10A: Continue to require remediation of hazardous material releases from previous land uses as part of any redevelopment activities. ■ Action NBE-5.10B: Continue to require environmental site assessments stipulated by State and County regulations for potential hazardous material releases from prior uses and assessments for lead and asbestos present in building materials. ○ Policy NBE-5.11: Risk Reduction. Reduce the risk of hazardous materials accidents, spills, and vapor releases, and minimize the effects of such incidents if they occur. ○ Policy MTC-2.3: Emergency Response Routes. Ensure adequate emergency vehicle access in all areas of Vallejo.
○ Action MTC-2.3B: Continue to involve the Police and Fire Departments in the development review process to ensure that applicable requirements for emergency access are met.

4.9.2 Background
The following discussion is based on the findings from the Phase I Environmental Site Assessment66 (Phase I ESA) prepared for the project site and the peer review of the Phase I ESA conducted as part of the environmental review process67. The Phase I ESA and peer review are included in Appendix F of this Initial Study.

The project site is vacant and undeveloped. The Phase I ESA completed for the proposed project determined that there are no recognized environmental conditions (RECs) identified in connection with the project site after completing a review of local, State, tribal, and federal environmental record sources; standard historical sources; aerial photographs; fire insurance maps; physical setting sources; a reconnaissance of the project site; and written/oral interviews with persons knowledgeable about past and current site use.
66 ENGEO. 2022b. Vallejo Properties – Glen Cove, Vallejo, California Phase I Environmental Site Assessment.

April 26. 67 Baseline Environmental Consulting. 2025. Peer Review of Phase I Environmental Site Assessment, Vista Cove Planned Development Project, Vallejo, California. March 25.

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4.9.3 Impact Analysis
a. Would the project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? (Less than Significant with Mitigation Incorporated, No New Impact)
The proposed project involves the subdivision of the 20.13-acre site and construction of 51 residential lots, internal roadways, undeveloped land, and related infrastructure improvements.

Because the proposed project is for private residential use, it would generally not involve transport, use, or disposal of significant quantities of hazardous materials. Only small quantities of chemicals would be used for routine maintenance that would not pose a significant threat to human or environmental health.

Construction of the proposed project would involve the use and transport of hazardous materials.

These materials could include fuels, oils, paints, and other chemicals used during construction activities. Handling and transportation of hazardous materials could result in accidental releases or spills and associated health risks to workers, the public, and the environment. To prevent the accidental release of hazardous materials into aquatic features within the project site that drain to the Carquinez Strait, Project Specific Mitigation Measures HAZ-1 and HAZ-2 would be required, which entail the preparation and implementation of an Emergency Response and Cleanup Plan and properly completing all construction equipment maintenance, refueling, and washing activities outside of riparian areas.

Transport and use of hazardous materials would be subject to all applicable State and federal laws, such as the Hazardous Materials Transportation Act, the Resource Conservation and Recovery Act, the California Hazardous Materials Management Act, the California Health and Safety Code, and CCR Title 8 and Title 22. Compliance with existing regulations and implementation of Project Specific Mitigation Measures HAZ-1 and HAZ-2 would ensure that the proposed project would not create a significant hazard to the public or the environment associated with the routine transport, use, or disposal of hazardous materials by ensuring these materials are properly handled during construction of the proposed project. These are standard measures applied to construction activities within sensitive natural areas. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

Project Specific Mitigation Measure HAZ-1 Emergency Response and Cleanup Plan. Prior to commencement of construction activities, the
construction contractor shall prepare an Emergency
Response and Cleanup Plan. The construction
contractor shall implement the plan during
construction. The plan shall detail the methods to
be used to contain and clean up a spill of petroleum
products or other hazardous materials in the work
area.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Project Specific Mitigation Measure HAZ-2 Construction Equipment Maintenance, Refueling, and Washing Activities. During construction, the
construction contractor shall ensure that all
equipment maintenance, refueling, and storage are
conducted on level ground outside the aquatic
features within the project site, away from
concentrated flows of stormwater and drainage
courses. Drip pans or absorbent pads shall be used
during equipment refueling and maintenance
activities. Adequate quantities of absorbent spill
cleanup material and spill kits shall be kept in the
refueling and maintenance area and on fuel trucks.

Spill cleanup materials shall be disposed of
immediately after use.
b. Would the project create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? (Less than Significant with Mitigation Incorporated, No New Impact)
There are two main ways that the public and/or the environment could be affected by the release of hazardous materials from the project site into the environment: (1) exposing workers and/or the public to potentially contaminated soil and groundwater during construction and/or operation of the project; or (2) exposing workers and/or the public to hazardous building materials (e.g., leadbased paint, asbestos) during demolition of existing structures.

The proposed project would not involve the demolition of any existing structures. The project site is vacant and undeveloped. Therefore, it is unlikely that the soil and groundwater are contaminated with significant toxic or hazardous materials that would be released during construction.

Additionally, the Phase I ESA completed for the proposed project determined that there are no recognized environmental conditions (RECs) identified in connection with the project site after completing a review of local, State, tribal, and federal environmental record sources; standard historical sources; aerial photographs; fire insurance maps; physical setting sources; a reconnaissance of the project site; and written/oral interviews with persons knowledgeable about past and current site use.

As described above, hazardous materials could be used at the project site during construction and operation of the proposed project. Improper use, storage, or handling could result in a release of hazardous materials into the environment, which could pose a risk to construction workers and the public. However, the project sponsor would be required to comply with existing government regulations related to the use and disposal of these materials, as detailed previously in Section 4.9.a, including Occupational Safety and Health Administration (OSHA) and California Division of Occupational Safety and Health (Cal/OSHA) regulations, CCR Title 8; the Construction General Permit (CGP); and United States Department of Transportation (DOT), Resource Conservation and Recovery Act (RCRA), and State regulations. Additionally, the proposed project would be subject to Project Specific Mitigation Measures HAZ-1 and HAZ-2 would be required, which require the preparation

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -94 and implementation of an Emergency Response and Cleanup Plan and properly completing all construction equipment maintenance, refueling, and washing activities outside of riparian areas. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. c. Would the project emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? (Less than Significant Impact, No New Impact)
The nearest school to the project site is St. Patrick-St. Vincent High School, located approximately

0.1 mile north of the project site. During operation of the proposed residential project, only small quantities of chemicals would be used for routine maintenance, which would not pose a significant threat to human or environmental health. Additionally, as noted in Sections 4.9.a and 4.9.b, the proposed project would comply with all applicable State and federal laws, such as the Hazardous Materials Transportation Act, the Resource Conservation and Recovery Act, the California Hazardous Materials Management Act, California Health and Safety Code, and CCR Title 8 and Title 22.

Construction of the proposed project would not create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials or create a hazard to the public and environment through reasonably foreseeable upset and accident conditions. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. d. Would the project be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment? (No Impact, No New Impact) The project site is not included on any list of hazardous materials site compiled pursuant to Government Code Section 65962.5,68 and no impact would occur. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
e. Would the project be located within an airport land use plan or, where such a plan has not been adopted, within 2 miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? (No Impact, No New Impact)
The project site is not located within 2 miles of a public airport or public use airport. The closest airports are Napa County Airport and Buchanan Field Airport, which are located approximately

9.5 miles northwest and southeast of the project site, respectively. Therefore, the proposed project would not result in a safety hazard or excessive noise for people residing or working in the area, and no impact would occur. No new impacts or substantially more severe significant impacts would 68 California Environmental Protection Agency (CalEPA). 2024. Cortese List Data Resources. Website:
https://calepa.ca.gov/sitecleanup/corteselist/ (accessed March 5, 2025).

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
f. Would the project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? (Less Than Significant Impact, No New Impact) The Vallejo General Plan 2040 Nature and Built Environment chapter addresses natural and humanmade hazards and dangers and offers methods to mitigate natural hazards, enhance disaster resistance, and promote public safety. The element focuses on natural disasters, including earthquake hazards (surface faulting, ground shaking, liquefaction, landslides, and tsunamis) and weather-related hazards (flooding, landslides, wildfires, drought, and climate change). The element does not identify specific evacuation routes within Vallejo.

The Solano County General Plan Public Health and Safety chapter discusses disaster preparedness, and the Solano County Office of Emergency Services (OES) is responsible for creating and maintaining the Solano County Emergency Operations Plan (EOP). The EOP establishes management organization and assigns functions and tasks consistent with California’s Standardized Emergency Management System (SEMS) and the National Incident Management System (NIMS). The EOP provides for the integration and coordination of planning efforts for Solano County, and its intent is to provide direction on how to respond for an emergency form the onset through extended response, and into the recovery process. The Solano County OES also prepares and maintains the Solano County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP), which identifies risks and ways to minimize damage from natural and human-made disasters. Section 7 of the MJHMP details the hazard mitigation planning elements specific to the City of Vallejo. Neither of these plans identify specific evacuation routes within the city or the county.

The proposed project would be consistent with the policies outlined in the Solano County General Plan Public Health and Safety chapter, the City of Vallejo General Plan Nature and Built Environment chapter, the Solano County EOP, and the Solano County MJHMP. The proposed project would not alter or block adjacent roadways, and implementation of the proposed project would not be expected to impair the function of nearby emergency evacuation routes. In addition, operation of the proposed project would not cause permanent alterations to vehicle circulation routes and patterns or impede public access or travel on public rights-of-way, as the proposed internal roadways would be accessible to neighborhood users and would terminate at the project site. Prior to approval of final maps and improvement plans for any development project within Vallejo, plan review and approval by the Vallejo Fire District is required. Internal roadways and ingress/egress for the project site would be required to meet State and local standards regarding turning radius, road width, and emergency vehicle access. Therefore, potential impacts to an adopted emergency response plan or emergency evacuation plan would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -96 g. Would the project expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires? (Less Than Significant Impact, No New Impact) According to the City of Vallejo General Plan 2040, the project site is located within a moderate- to high-risk wildfire area.69 There are no Very High Fire Hazard Areas in or adjacent to Vallejo.

Construction of the proposed project would involve the use of some flammable materials such as gasoline, diesel fuel, hydraulic oils, paints, solvents, or other wastes. During construction, there would be increased human activity and ignition sources, including equipment that could create sparks, be a source of heat, or leak flammable materials on the project site. However, all construction equipment is required to have fire suppression equipment (such as a fire extinguisher) on board or at the work site, secondary containment would be required for fuel-powered equipment, and a spill kit would be required to be kept on site during construction for use in case of any leaks or spills of flammable materials. These existing requirements would reduce the potential exacerbation of wildfire risks related to construction activities.

Operation of the proposed project would be consistent with adjacent residential uses and the allowable zoning for the project site. The proposed project would be subject to the design standards and guidelines as outlined in the City of Vallejo Municipal Code and would undergo Development Review to ensure that proposed structures conform with all applicable regulations. The proposed project would also be subject to requirements in Section 13000 et seq. of the California Health and Safety Code, the California Building Standards Code, and the California State Fire Code, which include regulations concerning the following: building standards for fire protection; fire protection and notification systems such as extinguishers and smoke alarms; safety for firefighters and emergency responders during emergency operations; minimum standards for hazardous vegetation and fuel management, defensible space, and building construction; and minimum standards for emergency access and water supply for fire response.

Compliance with these existing regulatory requirements would ensure that the proposed project would not exacerbate wildfire risks and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire. Impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. 69 Vallejo, City of. 2017. Propel Vallejo General Plan 2040, Map NBE-4. August 29.

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4.10 HYDROLOGY AND WATER QUALITY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Violate any water quality standards or waste discharge requirements or otherwise substantially degrade
surface or groundwater quality?
b. Substantially decrease groundwater supplies or
interfere substantially with groundwater recharge such
that the project may impede sustainable groundwater
management of the basin?
c. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the
course of a stream or river or through the addition of
impervious surfaces, in a manner which would:
i. Result in substantial erosion or siltation on- or offsite; ii. Substantially increase the rate or amount of surface runoff in a manner which would result in flooding
on- or offsite;
iii. Create or contribute runoff water which would
exceed the capacity of existing or planned
stormwater drainage systems or provide substantial
additional sources of polluted runoff; or
iv. Impede or redirect flood flows?
d. In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation?
e. Conflict with or obstruct implementation of a water
quality control plan or sustainable groundwater
management plan?

4.10.1 Prior Environmental Analysis
Chapter 4.8 of the General Plan EIR analyzed impacts to hydrology and water quality with build out of the General Plan, and determined that build out of the General Plan would result in less than significant impacts related to hydrology and water quality due to compliance with existing regulatory requirements including the SWRCB’s CGP, the MRP, City of Vallejo Municipal Code, Vallejo Sanitation and Flood Control District Code, National Flood Insurance Program standards, and California Division of Safety of Dams standards. No mitigation measures were prescribed. However, the General Plan includes the following goals, policies, and actions related to hydrology and water quality which would be applicable to the proposed project:
○ Policy NBE-1.1: Natural Resources. Protect and enhance hillsides, waterways, wetlands, and aquatic and wildlife habitat through land use decisions that avoid and mitigation potential environmental impacts on these resources to the extent feasible. ○ Policy NBE-1.7: Green Infrastructure. Encourage the installation of green infrastructure, including tools such as permeable pavement, rain gardens, constructed wetlands, grassy

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -98 swales, rain barrels and cisterns, and green roofs, to treat stormwater, attenuate floods, increase groundwater recharge, and reduce urban heat islands. ■ Action NBE-1.14C: Update the Green Building Standards Code to require the use of low flow plumbing fixtures, low volume irrigation systems, and drought-tolerant plant palettes.
• Goal NBE-5: Hazard Protection. Protect life and property from natural and human-made hazards.
○ Policy NBE-5.4: Project Location and Design. Prohibit development in any area where it is determined that the potential risk from natural hazards cannot be mitigated to acceptable levels.
■ Action NBE-5.4A: Continue to require geotechnical studies for land use proposals to determine engineering measures that may be necessary to adequately mitigate any seismic, flooding, sea level rise, landslide, erosion, or related risk. ■ Action NBE-5.4B: Continue to require drainage and erosion control measures for landslide-prone or geologically hazardous hillside areas to minimize risks to downhill areas.
■ Action NBE-5.6D: Continue to enforce City regulations that prohibit development, grading, and land modification activities that would adversely affect the local drainage system or create unacceptable erosion impacts.
○ Policy NBE-5.7: Design for Stormwater Control. Encourage new development and redevelopment to minimize the area of new roofs and paving.

4.10.2 Background
Unless otherwise noted, the following analysis is based on the Preliminary Stormwater Control Plan70 and the Drainage Study71 prepared for the proposed project. Copies of these reports are included in Appendix G of this Initial Study.

4.10.2.1 Water Quality Regulations
The State Water Resources Control Board (SWRCB) and nine Regional Water Quality Control Boards (RWQCBs) regulate the quality of surface water and groundwater bodies throughout California. In the Bay Area, including the project site, the San Francisco Bay RWQCB (Water Board) is responsible for implementation of the Water Quality Control Plan (Basin Plan). The Basin Plan establishes beneficial water uses and water quality objectives for waterways and water bodies within the region. Section 303(d) of the federal Clean Water Act (CWA) requires that states identify water bodies, including bays, rivers, streams, creeks, and coastal areas, that do not meet water quality 70 Sancerra Vista Cove, LLC. 2023. Preliminary Stormwater Control Plan for Vista Cove. November. 71 DK Engineering. 2023. Op. cit.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) standards and the pollutants that are causing the impairment. Total Maximum Daily Loads (TMDLs) describe the maximum amount of a pollutant that a water body can receive while still meeting established water quality standards. A TMDL establishes limits for pollutant discharges into impaired water bodies.

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

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

The proposed project would be subject to the California Regional Water Quality Control Board San Francisco Bay Region’s Municipal Regional Stormwater NPDES Permit (MRP), which went into effect on July 1, 2022, by Order R2-2022-0018, NPDES Permit No. CAS612008. The MRP covers stormwater discharges from municipalities and local agencies in Alameda, Contra Costa, San Mateo, and Santa Clara counties; the cities of Fairfield, Suisun City, and Vallejo; and the VFWD, which have joined to form the Solano Stormwater Alliance (Solano Permittees). Provision C.3 of the MRP requires new development and redevelopment projects that would replace more than 5,000 square feet of existing impervious surfaces to include post-construction stormwater control in project designs.

Under the Provision C.3 requirements, the preparation and submittal of a Stormwater Control Plan (SCP) would be required. The purpose of an SCP is to detail the design elements and implementation measures necessary to meet the post-construction stormwater control requirements of the MRP. In particular, SCPs must include Low Impact Development (LID) design measures, which reduce water quality impacts by preserving and recreating natural landscape features, minimizing imperviousness, and using stormwater as a resource rather than a waste product. Additionally, the preparation of a Stormwater Facility Operation and Maintenance Plan is required to ensure that stormwater control measures are inspected, maintained, and funded for the life of the project.

4.10.2.2 Project Site Hydrology
Under existing conditions, the project site consists entirely of pervious surface consisting primarily of grassland. There is no existing stormwater infrastructure on the project site, and the project site drains from west to east to Benicia State Park, where stormwater runoff converges and is directed to the Carquinez Strait.72 The Carquinez Strait drains to the San Pablo Bay, which drains to the San 72 DK Engineering. 2023. Op. cit.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -100 Francisco Bay, which drains to the Pacific Ocean. The receiving waters for stormwater runoff from the project site are listed as impaired on the 303(d) list for several constituents.73

4.10.2.3 Water Quality
The Carquinez Strait is listed as an impaired water body for the following pollutants: chlordane, dichlorodiphenyltrichloroethane (DDT), dieldrin, dioxin compounds (including 2,3,7,8-TCDD), furan compounds, invasive species, mercury, polychlorinated biphenyls (PCBs), PCBs (dioxin-like), and selenium. The San Pablo Bay is listed as an impaired water body for the following pollutants:
chlordane, DDT, dieldrin, dioxin compounds (including 2,3,7,8-TCDD), furan compounds, invasive species, mercury, PCBs, PCBs (dioxin like), and selenium. The San Francisco Bay, Central is listed as an impaired water body for the following pollutants: chlordane, DDT, dieldrin, dioxin compounds (including 2,3,7,8-TCDD), furan compounds, invasive species, mercury, PCBs, PCBs (dioxin like), selenium, and trash.

4.10.2.4 Groundwater
The project site is not located within a mapped Division of Water Rights groundwater basin boundary.74

4.10.2.5 Floodplains
According to Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) No. 06095C0629G, the project site is located in Zone X, which is identified as an area of minimal flood hazard.75

4.10.3 Impact Analysis
a. Would the project violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or groundwater quality? (Less Than Significant Impact, No New Impact)
Construction. The proposed project involves the subdivision of the 20.13-acre site and construction of 51 residential lots, internal roadways, undeveloped land and related infrastructure improvements.

Construction activities would result in the disturbance of 10.3 acres of soil. Pollutants of concern during construction include sediments, trash, petroleum products, concrete waste (dry and wet), sanitary waste, and chemicals. Each of these pollutants on its own or in combination with other pollutants can have a detrimental effect on water quality. During construction activities, excavated soil would be exposed, and there would be an increased potential for soil erosion and sedimentation compared to existing conditions. In addition, chemicals, liquid products, petroleum products 73 State Water Resources Control Board (SWRCB). 2024. 2024 California Integrated Report. Website:
https://www.waterboards.ca.gov/water_issues/programs/water_quality_assessment/2024-integratedreport.html (accessed March 5, 2025). 74 State of California Department of Water Resources (DWR). DWR Mapping Tool. Website: https://sgma. water.ca.gov/webgis/index.jsp?appid=gasmaster&rz=true (accessed September 19, 2024). 75 Federal Emergency Management Agency (FEMA). 2016. Flood Insurance Rate Map No. 06095C0629G.

Map Revised August 3, 2016. Website: https://msc.fema.gov/portal/search (accessed July 5, 2024).

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) (e.g., paints, solvents, and fuels), and concrete-related waste may be spilled or leaked, and they have the potential to be transported via stormwater runoff into receiving waters.

Because construction of the proposed project would disturb greater than 1 acre of soil, the project is subject to the requirements of the CGP, which requires preparation of a SWPPP and implementation of construction BMPs during construction activities as detailed above. Construction BMPs would include, but not be limited to, Erosion Control and Sediment Control BMPs designed to minimize erosion and retain sediment on site, as well as Good Housekeeping BMPs to prevent spills, leaks, and discharge of construction debris and waste into receiving waters.

As detailed in the Preliminary Geotechnical Exploration76 completed for the proposed project, no groundwater was encountered within the test pits, trench, and borings completed as part of the exploration. However, fluctuations in groundwater levels occur seasonally and over a period of years due to variations in precipitation, temperature, irrigation, and other factors. Construction of the proposed project would require excavation to a depth of up to 24 feet below the ground surface to accommodate foundations and utility infrastructure. Therefore, dewatering and shoring of groundwater may be required during construction activities involving excavation. Release of dewatered groundwater to surface waters can introduce total dissolved solids and other constituents to surface waters and could cause degradation of the receiving water quality. In the event that groundwater is encountered during construction and groundwater dewatering is necessary, any groundwater dewatering during excavation would be conducted in accordance with the requirements of the CGP. The CGP allows the discharge of dewatering effluent if the source of the water is uncontaminated groundwater and is properly filtered or treated using appropriate technology. The discharge of dewatering effluent is authorized under the CGP if the following conditions are met:
• The discharge does not cause or contribute to a violation of any water quality standard; • The discharge does not violate any other provision of the CGP; • The discharge is not prohibited by the applicable Basin Plan; • The discharger has included and implemented specific BMPs required by the CGP to prevent or reduce the contact of the nonstormwater discharge with construction materials or equipment; • The discharge does not contain toxic constituents in toxic amounts or (other) significant quantities of pollutants;
• The discharge is monitored and meets the applicable numeric action levels; and • The discharger reports the sampling information in the annual report. 76 ENGEO. 2022a. Vallejo Properties – Vista Cove, Vallejo, California, Preliminary Geotechnical Exploration.

September 12.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -102 If any of the above conditions are not satisfied, the discharge of dewatering effluent is not authorized by the CGP and the discharger must notify the local Regional Water Quality Control Board to determine whether a separate NPDES permit is necessary.

Adherence with the CGP, including implementation of the required SWPPP, Construction BMPs, and dewatering requirements, would ensure construction impacts related to surface water quality standards, waste discharge requirements, and surface water quality would be less than significant.

Operation. Pollutants of concern from long-term operations include pathogens (bacteria/viruses), nutrients, pesticides/herbicides, sediments/total suspended solids, trash and debris, and oil and grease. The City of Vallejo is under the purview of the MRP. Therefore, the proposed project would be subject to the requirements of Provision C.3 of the MRP because the project would result in new development consisting of more than 5,000 square feet of impervious surfaces. As such, the preparation and implementation of an SCP, including a Stormwater Facility Operation and Maintenance Plan, would be required. As discussed in Chapter 2.0, Project Description, the proposed project would include two detention basins and approximately 7,617 square feet of bioretention space that would be used for stormwater control and treatment to reduce pollutants of concern in stormwater prior to release into the marshland area adjacent to Benicia State Park. Therefore, compliance with the requirements of the MRP would ensure that operational impacts to water quality would be less than significant.

Overall, because the proposed project would be required to comply with existing regulations, including the CGP and the MRP, the proposed project would not violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or groundwater quality.

Impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
b. Would the project substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? (Less than Significant Impact, No New Impact) The project site is not located within a mapped Division of Water Rights groundwater basin boundary.77 Impacts related to groundwater recharge are discussed below.

Construction. As detailed in the Preliminary Geotechnical Exploration completed for the proposed project, no groundwater was encountered within the test pits, trench, and borings completed as part of the exploration. However, fluctuations in groundwater levels occur seasonally and over a period of years due to variations in precipitation, temperature, irrigation, and other factors. Construction of the proposed project would require excavation to a depth of up to 24 feet below the ground surface to accommodate foundations and utility infrastructure. Therefore, dewatering and shoring of groundwater may be required during construction activities involving excavation. Such dewatering 77 State of California Department of Water Resources (DWR). DWR Mapping Tool. Website: https://sgma. water.ca.gov/webgis/index.jsp?appid=gasmaster&rz=true (accessed September 19, 2024).

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) would be localized and temporary and would not result in the lowering of surrounding groundwater levels and would have to comply with the CGP, as detailed above.

Operation. The City of Vallejo provides water to the project site. The City’s potable water supply is derived from various surface sources, including the Sacramento River watershed; the Solano Project from Putah Creek watershed, including Lake Berryessa; the Wild Horse Creek watershed; and the Upper Suisun Creek watershed (future water source).78 Because the City does not use groundwater for municipal water supply, water use during operation of the proposed project would not affect groundwater supplies.

Development of the proposed project would result in an increase in impervious surfaces on the project site from 0 acres to approximately 3.95 acres, which could decrease on-site infiltration.

However, in compliance with MRP, the proposed project would include two detention basins and approximately 7,617 square feet of bioretention space that would be used for stormwater control and treatment. Due to the incorporation of bioretention space and the implementation of LID techniques as required by the MRP, the proposed project would not result in a significant decrease in groundwater recharge that would result in a net deficit in aquifer volume or a lowering of the local groundwater table level. Therefore, the proposed project would not interfere with groundwater recharge.

For the reasons listed above, impacts related to the decrease of groundwater supplies or interference with groundwater recharge would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. c. Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would:
i. Result in substantial erosion or siltation on- or off-site; (Less than Significant Impact, No New Impact)
During construction activities, more than 1 acre of soil would be disturbed. Soil would be exposed, and drainage patterns would be temporarily altered during grading and other construction activities, and there would be an increased potential for soil erosion and siltation compared to existing conditions. Additionally, during a storm event, soil erosion and siltation could occur at an accelerated rate. As required by the CGP a SWPPP would be prepared to identify construction BMPs to be implemented as part of the proposed project to reduce impacts on water quality during construction, including those impacts associated with soil erosion and siltation. With compliance with the requirements in the CGP and implementation of construction BMPs, construction impacts related to on- or off-site erosion or siltation would be less than significant.

After the completion of project construction, operation of the proposed project would result in an increase in impervious surfaces on the project site from 0 acres to approximately 3.95 acres, which 78 Vallejo, City of. 2021. City of Vallejo 2020 Urban Water Management Plan. October 12.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -104 would result in a net increase in stormwater runoff that could lead to downstream erosion in receiving waters. However, as discussed above, two detention basins and approximately 7,617 square feet of bioretention space included in the project’s design in compliance with the MRP would be used for stormwater control and treatment. Due to the incorporation of bioretention space and implementation of LID techniques as required by the MRP, operational impacts related to on- or offsite erosion or siltation would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
ii. Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or offsite; (Less than Significant Impact, No New Impact) Development of the proposed project would result in an increase in impervious surfaces on the project site from 0 acres to approximately 3.95 acres, which could have the potential to increase the volume and rate of stormwater runoff discharged from the project site. However, as previously discussed, the two detention basins and approximately 7,617 square feet of bioretention space included in the project’s design in compliance with the MRP would be used for stormwater control and treatment. The proposed drainage facilities and BMPs needed to accommodate stormwater runoff would be appropriately sized so that on-site flooding would not occur. Therefore, due to the implementation of LID techniques as required by the MRP, the proposed project would not substantially increase the rate or amount of surface runoff in a manner that would result in flooding on or off site. Impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
iii. Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; or (Less than Significant Impact No, New Impact)
Stormwater Drainage System Capacity. Under existing conditions, the project site consists entirely of pervious surface consisting primarily of grassland. There is no existing stormwater infrastructure on the project site, and the project site drains from west to east to Benicia State Park, where stormwater runoff converges and is directed to the Carquinez Strait.79 The proposed project would include two detention basins and approximately 7,617 square feet of bioretention space, made up of two bioretention facilities located at the northwest corner of the site and the middle east border of the site that would collect drainage from the proposed on-site stormwater infrastructure and be used for stormwater control and treatment before discharging to an 18-inch storm drain pipe that outfalls to the existing marshland area adjacent to Benicia State Park. The storm drain system would be designed and installed to VFWD standards.

As detailed above, the proposed project would be required to comply with the MRP and would include the incorporation of LID design features, including bioretention areas that would be used for stormwater control and treatment. The proposed drainage facilities and BMPs needed to 79 DK Engineering. 2023. Op. cit.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) accommodate stormwater runoff would be appropriately sized such that drainage facility capacity would not be exceeded during a design storm. Therefore, the proposed project would not result in an exceedance of planned or existing stormwater drainage systems and impacts would be less than significant.

Polluted Runoff. As discussed in Section 4.10.a, pollutants of concern during construction include sediments, trash, petroleum products, concrete waste (dry and wet), sanitary waste, and chemicals.

Each of these pollutants on its own or in combination with other pollutants can have a detrimental effect on water quality. Drainage patterns would be temporarily altered during grading and other construction activities, and construction-related pollutants could be spilled, leaked, or transported via storm runoff into adjacent drainages and downstream receiving waters. However, as previously discussed, the proposed project would be required to comply with the requirements set forth by the CGP and SWPPP, which would specify BMPs to be implemented to control the discharge of pollutants in stormwater runoff as a result of construction activities. Therefore, construction-related impacts would be less than significant.

Expected pollutants of concern from long-term operations include pathogens (bacteria/viruses), nutrients, pesticides/herbicides, sediments/total suspended solids, trash and debris, and oil and grease. As previously discussed, compliance with the MRP and the implementation of LID techniques would ensure that the proposed project would not exceed the capacity of existing or planned stormwater drainage systems or discharge substantial sources of polluted runoff from the project site. Operation-related impacts would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
iv. Impede or redirect flood flows? (No Impact, No New Impact) According to Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) No. 06095C0629G, the project site is located in Zone X, which is identified as an area of minimal flood hazard.80 Additionally, the proposed project would not substantially alter drainage patterns. Because the proposed project would not place improvements and structures directly within a 100-year floodplain, the proposed project would not impede or redirect flood flows, and there would be no impact. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. d. In flood hazard, tsunami, or seiche zones, would the project risk release of pollutants due to project inundation? (No Impact, No New Impact)
Flooding. According to FEMA FIRM No. 06095C0629G, the project site is located in Zone X, which is identified as an area of minimal flood hazard.81 Therefore, the proposed project would not risk release of pollutants due to project inundation by flood hazard. 80 Federal Emergency Management Agency (FEMA). 2016. Flood Insurance Rate Map No. 06095C0629G.

Map Revised August 3, 2016. Website: https://msc.fema.gov/portal/search (accessed July 5, 2024). 81 Ibid.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -106 Tsunami. The project site is not within a mapped tsunami hazard area.82 Furthermore, the risk of flooding due to a tsunami event is considered to be low for Vallejo.83 No impact would occur.

Seiches. Seiches are waves created in an enclosed body of water (e.g., a bay, lake, or harbor) that go up and down or oscillate and do not progress forward like standard ocean waves. Limited isolated damage to adjacent and downslope structures has been observed from seiches occurring in swimming pools and in small shallow lakes and ponds. There are no sizeable, enclosed bodies of water in the vicinity of the project site. The project site is approximately 1 mile from the Carquinez Strait; however, no seiches have ever been recorded in the Bay Area84 and the project site is at a higher elevation and would not be inundated in the event of a seiche. No impact would occur.

Dam Inundation. The project site is not within a mapped dam failure inundation area.85 Therefore, the project site is not at risk of inundation due to dam failure. No impact would occur.

Overall, the proposed project would not risk release of pollutants due to project inundation by flooding, tsunami, seiches, or dam inundation. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
e. Would the project conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? (Less Than Significant Impact, No New Impact) In the Bay Area, including the project site, the Water Board is responsible for implementation of the Basin Plan, which establishes beneficial water uses for waterways and water bodies within the region. As previously discussed, the proposed project would comply with existing NPDES permit requirements, including the CGP and MRP, and would implement construction and operational BMPs to reduce pollutants of concern in stormwater runoff as detailed above. Compliance with these regulatory requirements would ensure that the proposed project would not degrade or alter water quality, causing the receiving waters to exceed the water quality objectives, or impair the beneficial use of receiving waters. As such, the proposed project would not result in water quality impacts that would conflict with the Basin Plan. Construction and operational impacts related to a conflict with the Basin Plan would be less than significant.

The Sustainable Groundwater Management Act (SGMA), which was enacted in September 2014, requires governments and water agencies of high- and medium-priority basins to halt overdraft of groundwater basins. The SGMA requires the formation of local Groundwater Sustainability Agencies (GSAs), which are required to adopt Groundwater Sustainability Plans to manage the sustainability of the groundwater basins. The project site is not located within a mapped Division of Water Rights groundwater basin boundary and is not subject to a sustainable groundwater management plan. 82 California Department of Conservation (DOC). 2024. Solano County Tsunami Hazard Areas. Website:
https://www.conservation.ca.gov/cgs/tsunami/maps/Solano (accessed October 25, 2024). 83 Vallejo, City of. 2016. Propel Vallejo General Plan Update and Sonoma Boulevard Specific Plan EIR for the City of Vallejo. July. 84 Ibid. 85 Ibid.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) Nevertheless, as detailed in Section 4.10.b, the proposed project would not interfere with groundwater recharge in the vicinity of the project site. For these reasons, the proposed project would not conflict with or obstruct the implementation of a sustainable groundwater management plan, and this impact would be less than significant. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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4.11 LAND USE AND PLANNING
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Physically divide an established community?
b. Cause a significant environmental impact due to a
conflict with any land use plan, policy, or regulation
adopted for the purpose of avoiding or mitigating an
environmental effect?

4.11.1 Prior Environmental Analysis
Chapter 4.9 of the General Plan EIR analyzed impacts related to land use and planning associated with build out of the General Plan and determined that build out of the General Plan would result in less than significant impacts related to land use and planning and would not divide an established community or conflict with established plans, policies, and regulations. No mitigation measures were prescribed. The General Plan does not include any goals, policies, or actions related to land use which would be applicable to the proposed project.

4.11.2 Background
The project site is located in an urban area in Vallejo and is generally surrounded by residential, recreational, and open space uses. The City of Vallejo General Plan 2040 designates the project site as Mix of Housing Types (R-MH) and Primarily Single Family (R-SF). The project site is currently zoned Residential Medium Density (RMD) and Residential Low Density (RLD) on the City’s Zoning Map and would be rezoned a Planned Development (PD) Zoning District.

4.11.3 Impact Analysis
a. Would the project physically divide an established community? (No Impact, No New Impact) The physical division of an established community typically refers to the construction of a physical feature (such as an interstate highway or railroad tracks) or removal of a means of access (such as a local road or bridge) that would impair mobility within an existing community or between a community and outlying area. For instance, the construction of an interstate highway through an existing community may constrain travel from one side of the community to another; similarly, such construction may also impair travel to areas outside the community.

The project site is located in an urban area in Vallejo and is generally surrounded by residential, recreational, and open space uses. The project site is bordered to the north by I-780 and vacant land that is zoned for Public and Semi-Public uses. Farther north is a variety of Public and Semi-Public uses, including a California Highway Patrol office, St. Patrick-St. Vincent High School, and single- and multifamily residential uses. The project site is bordered immediately to the east by vacant, undeveloped land zoned for resource conservation and the Benicia State Recreation Area. Farther east are commercial uses and single- and multifamily residential uses. The project site is bordered

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) immediately to the south by vacant undeveloped land owned by the City and zoned for parks, recreation and open space, and resource conservation. Farther south are single-family residential uses and Glen Cove Elementary School. The project site is bordered immediately to the west by a 141-unit single-family residential subdivision. Farther west are commercial uses and single-family residential uses. The proposed project would include the development of the project site with residential uses, consistent with the adjacent residential communities in the surrounding area west of the project site. The proposed project would not require the construction of any new infrastructure that would divide an established community and would not remove any means of access. Therefore, the proposed project would not result in the physical division of an established community or adversely affect the continuity of land uses in the vicinity and there would be no impact. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR. b. Would the project cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? (Less Than Significant Impact, No New Impact)
The City of Vallejo General Plan 2040 designates the project site as Mix of Housing Types (R-MH) and Primarily Single Family (R-SF). Permitted land uses within the R-MH and R-SF designations are similar and include single-family homes. In addition, the land use designations allow for duplexes, triplexes fourplexes, smaller scale apartment buildings, and small commercial spaces; and public facilities such as schools, religious institutions, parks, and other community facilities appropriate within a residential neighborhood. The maximum permitted residential density in the R-MH designation is 25 dwelling units per acre, while in the R-SF designation it is 9 dwelling units per acre; however, in single-family areas where accessory dwelling units are allowed, the maximum permitted residential density is 12 dwelling units per acre. The proposed project would develop approximately 10 acres of the project site with 51 residential units, resulting in an overall density of 4.9 dwelling units per acre, which meets the residential density standard for both the R-MH and R-SF designations.

As previously stated, the project site is currently zoned Residential Medium Density (RMD) and Residential Low Density (RLD) on the City’s Zoning Map and would be rezoned a Planned Development (PD) Zoning District. RLD allows for primary single-family and RMD allows for a mix of housing types/medium density. The PD District is established to encourage the arrangement of a compatible variety of uses on suitable lands in such a manner that the resulting development will be in accord with the policies of the City’s Municipal Code, Section 16.209, to provide flexibility by allowing diversification in regulations such as building relationships, setbacks, height limitations, lot sizes, types of structures, parking, and the amount and location of open space86 The PD District requires development to conform to existing land use designations, and the minimum area of a PD Zoning District shall be 4 contiguous acres. The project site is 20.13 acres and, as discussed above, the proposed development would be consistent with the existing General Plan land use designations and would not exceed the allowable densities associated with the R-MH and 86 Vallejo, City of. n.d.-e. Vallejo, California – Municipal Code, Title 16 – Zoning, Part II – Districts and Development Types, Chapter 16.209 – Planned Development District.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -110 R-SF designations. Therefore, the proposed project would be consistent with the development regulations of the PD Zoning District.

Additionally, the proposed project would be required to undergo Site Development Review and Design Review consistent with Sections 16.604 and 16.605 of the Vallejo Municipal Code, which would provide for the review of the physical improvements to the project site, to ensure compatibility and compliance with City requirements. Additionally, the proposed project would also require building permits, a use permit, Landscape Review, and Tentative Map Approval. The proposed project would not conflict with an adopted land use plan, policy, or regulations. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to land use impacts analyzed in the General Plan EIR.

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4.12 MINERAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project:
a. Result in the loss of availability of a known mineral resource that would be of value to the region and the
residents of the state?
b. Result in the loss of availability of a locally-important mineral resource recovery site delineated on a local
general plan, specific plan or other land use plan?

4.12.1 Prior Environmental Analysis
The topic of mineral resources was discussed in Chapter 6.0 of the General Plan EIR, which determined that no impact to mineral resources with build out of the General Plan would occur as there are no formal mineral resource deposits located within the city limits. No mitigation measures were prescribed. There are no General Plan goals, policies, or actions related to mineral resources which would be applicable to the proposed project.

4.12.2 Background
Minerals are any naturally occurring chemical element or compound, or groups of elements and compounds, formed from inorganic processes and organic substances, including, but not limited to, coal, peat, and oil-bearing rock, but excluding geothermal resources, natural gas, and petroleum.

Rock, sand, gravel, and earth are also considered minerals by the DOC when extracted by surface mining operations.

The project site is within an urbanized area in Vallejo, and there are no known mineral resources within the vicinity of the project site that would be of value to the region or to the State.

4.12.3 Impact Analysis
a. Would the project result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? (No Impact, No New Impact) The project site is within an urbanized area in Vallejo, and there are no known mineral resources within the vicinity of the project site that would be of value to the region or to the State.

Additionally, according to the Propel Vallejo General Plan Update and Sonoma Boulevard Specific Plan Draft EIR,87 no formal mineral resource deposits are located within the city limits. Therefore, development of the proposed project would not result in the loss of available mineral resources and no impact related to mineral resources would occur. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.
87 Vallejo, City of. 2016. Op. cit.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -112 b. Would the project result in the loss of availability of a locally-important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? (No Impact, No New Impact)
Please refer to Section 4.12.a. The proposed project would not result in the loss of availability of any known locally important mineral resource recovery site. Therefore, no impact related to the availability of a locally important mineral resources recovery site would occur. No new impacts or substantially more severe significant impacts would result with implementation of the proposed project when compared to those analyzed in the General Plan EIR.

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4.13 NOISE
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
No New
Impact
Would the project result in:
a. Generation of a substantial temporary or permanent
increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable
standards of other agencies?
b. Generation of excessive groundborne vibration or
groundborne noise levels?
c. For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a
plan has not been adopted, within 2 miles of a public
airport or public use airport, would the project expose people residing or working in the project area to
excessive noise levels?

4.13.1 Prior Environmental Analysis
Chapter 4.10 of the General Plan EIR analyzed noise impacts associated with build out of the general Plan and determined that development under the General Plan would cause a substantial permanent increase in ambient transportation-related noise levels in the city during construction and operation. Therefore, the General Plan prescribed Mitigation Measure NOI-3, which details technological advances for noise generating vehicles and machinery and universal use of noise attenuating features, and General Plan EIR Mitigation Measure NOI-4, which provides specific construction noise measures to be included as conditions of approval for development projects.

However, the requirements in General Plan EIR Mitigation Measure NOI-3 were determined to be infeasible, and this impact and the cumulative noise impact was determined to be significant and unavoidable.

Additionally, the General Plan includes the following goals, policies, and actions related to noise which would be applicable to the proposed project:
○ Policy NBE-5.13: Noise Control. Ensure that noise does not affect quality of life in the community.
■ Action NBE-5.13A: Continue to require that new noise-producing uses are located sufficiently far away from noise-sensitive receptors and/or include adequate noise mitigation, such as screening, barriers, sound enclosures, noise insulation, and/or restrictions on hours of operation.
■ Action NBE-5.13C: Update City regulations to restrict the allowable hours to between 7 a.m. and 7 p.m. on weekdays for construction, demolition, maintenance, and loading/unloading activities that may impact noise-sensitive land use.

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4 P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) -114 ○ Policy NBE-5.14: Vibration Control. Ensure that vibration does not affect quality of life in the community.
■ Action NBE-5.14A: Update City regulations to establish quantified vibration level limits similar to commonly used guidelines found in the Federal Transit Administration document “Transit Noise and Vibration Impact Assessment.” ○ Policy NBE-5.15: Noise Compatibility Standards. Apply the General Plan noise and land use compatibility standards to all new residential, commercial, and mixed-use development and redevelopment.
■ Action NBE-5.15A: For new single-family residential projects, use a standard of 60 Ldn for exterior noise in private use areas, and require appropriate impact mitigation. ■ Action NBE-5.15D: Require maximum interior noise levels at 45 Ldn in all new residential units and require appropriate impact mitigation.
■ Action NBE-5.15E: When approving new development, limit project-related noise increases to the following for permanent stationary and transportation-related noise sources:
□ no more than 10 dB in non-residential areas;
□ no more than 5 dB in residential areas where the with-project noise level is less than the maximum "normally acceptable" level in the Noise and Land Use Compatibility figure; and
□ no more than 3 dB where the with-project noise level exceeds the "normally acceptable" level in Noise and Land Use Compatibility figure. ■ Action NBE-5.15F: Require acoustical studies with appropriate mitigation measures for projects that are likely to be exposed to noise levels that exceed the ‘normally acceptable’ standard and for any other projects that are likely to generate noise in excess of these standards.

4.13.2 Background
The following discussion is based on the findings from the Noise Impact Analysis88 prepared for the proposed project, which is included in Appendix H of this Initial Study.

4.13.2.1 Existing Noise Levels
To assess the existing noise level environment, noise levels are referenced from the Propel Vallejo General Plan 2040 and Sonoma Boulevard Specific Plan Draft EIR.89 The proposed project lies within 88 Urban Crossroads. 2025. Vista Cove Noise Impact Analysis, City of Vallejo. April. 89 City of Vallejo. 2016. Propel Vallejo General Plan 2040 and Sonoma Boulevard Specific Plan Draft EIR. July.

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P:\2024\20241845 CYV Vista Cove Project\PRODUCTS\Subsequent MND\Public Review\Vista Cove MND_Public Review.docx (11/05/25) the 70 A-weighted decibel (dBA) Community Noise Equivalent Level90 (CNEL) traffic noise contour of Interstate 780 (I-780) and the freeway segment from Columbus Parkway to Glen Cove Parkway exposes adjacent land uses to 77.7 dBA CNEL at 100 feet from the centerline. The background ambient noise levels in the vicinity of the project site is considered to be dominated by the transportation-related noise associated with I-780.

4.13.2.2 Noise Monitoring Locations
To assess the potential for long-term operational and short-term construction noise impacts and short-term vibration impacts, six sensitive receiver locations were identified as representative locations for analysis as further detailed below (refer to Figure 4.13-1). The selection of receiver locations is based on Federal Highway Administration (FHWA) guidelines and is consistent with additional guidance provided by the California Department of Transportation (Caltrans) and the Federal Transit Administration (FTA). Sensitive receivers are generally defined as locations where people reside or where the presence of unwanted sound could otherwise adversely affect the use of the land.

Noise-sensitive land uses are generally considered to include schools, hospitals, single-family dwellings, mobile home parks, churches, libraries, and recreation areas. Sensitive receivers near the project site include single-family residences, the closest of which is approximately 30 feet south of the project site, and Saint Patrick Saint Vincent Catholic High School. Other sensitive land uses in the project vicinity that are located at greater distances than those identified in Figure 4.13-1, will experience lower noise levels than those identified in this analysis due to the additional attenuation from distance and the shielding of intervening structures.91 The six identified sensitive receivers are as follows:
• R1: Location R1 represents existing noise sensitive single-family residence at 190 Buckeye Lane, approximately 90 feet southwest of the project site. Receiver R1 is placed near the private outdoor living area (backyard) facing the project site. • R2: Location R2 represents the existing noise sensitive single-family residence at 180 Ironwood Lane, approximately 80 feet south of the project site. Receiver R2 is placed near the private outdoor living area (backyard) facing the project site. • R3: Location R3 represents the existing noise sensitive single-family residence at 196 Shady Lane, approximately 30 feet south of the project site. Receiver R3 is placed near the private outdoor living area (backyard) facing the project site. • R4: Location R4 represents the existing noise sensitive single-family residence at 156 Wildflower Avenue, approximately 114 feet west of the project site. Receiver R4 is placed near the private outdoor living area (backyard) facing the project site. 90 Community Noise Equivalent Level (CNEL) is a 24-hour average noise metric that accounts for the increased sensitivity to noise during the evening and nighttime hours. 91 Urban Crossroads. 2025. Op. cit.

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LSA
$
100 200
FEET
SOURCE: Nearmap (9/4/2024)
l=l Project Location
0 Limit Of Disturbance
0 Receiver Locations
• Distance from Receiver to Project Site Boundary (ft)
l:\2024\20241845\GIS\Pro\Vista Cove Planned Development Project\Vista Cove Planned Development Project.aprx (5/29/2025) FIGURE 4.13-1
Vista Cove Planned Development Project
Sensitive Receiver Locations