St. Helena City Council
June 26, 2023

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(PRC Section 25402(d)) and cost effectiveness (PRC Sections 25402(b)(2) and (b)(3)). These standards are updated to consider and incorporate new energy-efficient technologies and construction methods. As a result, these standards save energy, increase electricity supply reliability, increase indoor comfort, avoid the need to construct new power plants, and help preserve the environment.

The current Title 24 standards are the 2019 Title 24 Building Energy Efficiency Standards, which became effective on January 1, 2020. In general, single-family residences built to the 2019 standards are anticipated to use approximately 7% less energy due to energy efficiency measures than those built to the 2016 standards; once rooftop solar electricity generation is factored in, single-family residences built under the 2019 standards would use approximately 53% less energy than those under the 2016 standards (CEC 2018). Nonresidential buildings built to the 2019 standards are anticipated to use an estimated 30% less energy than those built to the 2016 standards due mainly to lighting upgrades (CEC 2018).

Title 24, Part 11. In addition to the CEC’s efforts, in 2008, the California Building Standards Commission adopted the nation’s first green building standards. The California Green Building Standards Code (Part 11 of Title 24) is commonly referred to as California’s Green Building Standards (CALGreen), and establishes minimum mandatory standards and voluntary standards pertaining to the planning and design of sustainable site development, energy efficiency (in excess of the California Energy Code requirements), water conservation, material conservation, and interior air quality. The CALGreen standards took effect in January 2011 and instituted mandatory minimum environmental performance standards for all ground-up, new construction of commercial, low-rise residential and state-owned buildings and schools and hospitals. The CALGreen 2019 standards, which are the current standards, became effective January 1, 2020.

Title 20. Title 20 of the California Code of Regulations requires manufacturers of appliances to meet state and federal standards for energy and water efficiency. Performance of appliances must be certified through the CEC to demonstrate compliance with standards. New appliances regulated under Title 20 include refrigerators, refrigerator-freezers, and freezers; room air conditioners and room air-conditioning heat pumps; central air conditioners; spot air conditioners; vented gas space heaters; gas pool heaters; plumbing fittings and plumbing fixtures; fluorescent lamp ballasts; lamps; emergency lighting; traffic signal modules; dishwaters; clothes washers and dryers; cooking products; electric motors; low-voltage dry-type distribution transformers; power supplies; televisions and consumer audio and video equipment; and battery charger systems. Title 20 presents protocols for testing each type of appliance covered under the regulations, and appliances must meet the standards for energy performance, energy design, water performance, and water design. Title 20 contains three types of standards for Agenda Item #6.2.

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appliances: federal and state standards for federally regulated appliances, state standards for federally regulated appliances, and state standards for non-federally regulated appliances.

SB 1. SB 1 (2006) established a $3 billion rebate program to support the goal of the state to install rooftop solar energy systems with a generation capacity of 3,000 megawatts through 2016. SB 1 added sections to the Public Resources Code, including Chapter 8.8, California Solar Initiative, that require building projects applying for ratepayer-funded incentives for photovoltaic systems to meet minimum energy efficiency levels and performance requirements.

Section 25780 established that it is a goal of the state to establish a self-sufficient solar industry in which solar energy systems are a viable mainstream option for homes and businesses within 10 years of adoption, and to place solar energy systems on 50% of new homes within 13 years of adoption. SB 1, also termed “GoSolarCalifornia,” was previously titled “Million Solar Roofs.” AB 1470. This bill established the Solar Water Heating and Efficiency Act of 2007. The bill made findings and declarations of the Legislature relating to the promotion of solar water heating systems and other technologies to reduce natural gas demand. The bill defined several terms for purposes of the act. The bill required the CEC to evaluate the data available from a specified pilot program, and, if it made a specified determination, to design and implement a program of incentives for the installation of 200,000 solar water heating systems in homes and businesses throughout the state by 2017.

AB 1109. Enacted in 2007, AB 1109 required the CEC to adopt minimum energy efficiency standards for general purpose lighting to reduce electricity consumption by 50% for indoor residential lighting and by 25% for indoor commercial lighting.

Renewable Energy and Energy Procurement
SB 1078. SB 1078 (2002) established the RPS program, which requires an annual increase in renewable generation by the utilities equivalent to at least 1% of sales, with an aggregate goal of 20% by 2017. This goal was subsequently accelerated, requiring utilities to obtain 20% of their power from renewable sources by 2010.

SB 1368. SB 1368 (2006) requires the CEC to develop and adopt regulations for GHG emissions performance standards for the long-term procurement of electricity by local publicly owned utilities. These standards must be consistent with the standards adopted by the California Public Utilities Commission. This effort will help protect energy customers from financial risks associated with investments in carbon-intensive generation by allowing new capital investments in power plants whose GHG emissions are as low as or lower than new combined-cycle natural gas plants by requiring imported electricity to meet GHG performance standards in California and by requiring that the standards be developed and adopted in a public process.

Agenda Item #6.2.

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SB X1 2. SB X1 2 (2011) expanded the RPS by establishing that 20% of the total electricity sold to retail customers in California per year by December 31, 2013, and 33% by December 31, 2020, and in subsequent years be secured from qualifying renewable energy sources. Under the bill, a renewable electrical generation facility is one that uses biomass, solar thermal, photovoltaic, wind, geothermal, fuel cells using renewable fuels, small hydroelectric generation of 30 megawatts or less, digester gas, municipal solid waste conversion, landfill gas, ocean wave, ocean thermal, or tidal current, and that meets other specified requirements with respect to its location. In addition to the retail sellers previously covered by the RPS, SB X1 2 added local, publicly owned electric utilities to the RPS.

SB 350. SB 350 (2015) further expanded the RPS by establishing that 50% of the total electricity sold to retail customers in California per year by December 31, 2030, be secured from qualifying renewable energy sources. In addition, SB 350 includes the goal to double the energy efficiency savings in electricity and natural gas final end uses (such as heating, cooling, lighting, or class of energy uses on which an energy-efficiency program is focused) of retail customers through energy conservation and efficiency. The bill also requires the California Public Utilities Commission, in consultation with the CEC, to establish efficiency targets for electrical and gas corporations consistent with this goal.

SB 100. SB 100 (2018) increased the standards set forth in SB 350 establishing that 44% of the total electricity sold to retail customers in California per year by December 31, 2024, 52% by December 31, 2027, and 60% by December 31, 2030 be secured from qualifying renewable energy sources. SB 100 states that it is the policy of the State that eligible renewable energy resources and zero-carbon resources supply 100% of the retail sales of electricity to California.

This bill requires that the achievement of 100% zero-carbon electricity resources do not increase the carbon emissions elsewhere in the western grid and that the achievement not be achieved through resource shuffling.

Mobile Sources
AB 1493. In a response to the transportation sector accounting for more than half of California’s CO2 emissions, AB 1493 was enacted in July 2002. AB 1493 required CARB to set GHG emission standards for passenger vehicles, light-duty trucks, and other vehicles determined by the state board to be vehicles that are primarily used for noncommercial personal transportation in the state. The bill required that CARB set GHG emission standards for motor vehicles manufactured in 2009 and all subsequent model years. CARB adopted the standards in September 2004. In 2009–2012, standards resulted in a reduction of approximately 22% in GHG emissions compared to emissions from the 2002 fleet, and in 2013–2016, standards resulted in a reduction of approximately 30%.

Agenda Item #6.2.

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EO S-1-07. Issued on January 18, 2007, EO S-1-07 sets a declining low-carbon fuel standard for GHG emissions measured in CO2e grams per unit of fuel energy sold in California. The target of the low-carbon fuel standard is to reduce the carbon intensity of California passenger vehicle fuels by at least 10% by 2020. Carbon intensity measures the amount of GHG emissions in the lifecycle of a fuel, including extraction/feedstock production, processing, transportation, and final consumption, per unit of energy delivered. CARB adopted the implementing regulation in April 2009. The regulation is expected to increase the production of biofuels, including those from alternative sources, such as algae, wood, and agricultural waste.

SB 375. SB 375 (2008) addresses GHG emissions associated with the transportation sector through regional transportation and sustainability plans. SB 375 required CARB to adopt regional GHG reduction targets for the automobile and light-truck sector for 2020 and 2035. Regional Metropolitan Planning Organizations are then responsible for preparing a Sustainable Communities Strategy (SCS) within their Regional Transportation Plan. The goal of the SCS is to establish a forecasted development pattern for the region that, after considering transportation measures and policies, will achieve, if feasible, the GHG reduction targets. If an SCS is unable to achieve the GHG reduction target, a Metropolitan Planning Organization must prepare an Alternative Planning Strategy demonstrating how the GHG reduction target would be achieved through alternative development patterns, infrastructure, or additional transportation measures or policies.

Pursuant to Government Code Section 65080(b)(2)(K), an SCS does not regulate the use of land; supersede the land use authority of cities and counties; or require that a city’s or county’s land use policies and regulations, including those in a general plan, be consistent with it.

Nonetheless, SB 375 makes regional and local planning agencies responsible for developing those strategies as part of the federally required metropolitan transportation planning process and the state-mandated housing element process.

On September 23, 2010, CARB adopted the SB 375 targets for the regional Metropolitan Planning Organizations. CARB set a target of 7% per capita reduction by 2020 and a 15% per capita reduction by 2035 for the Bay Area. The ABAG and the Metropolitan Transportation Commission, which is the Metropolitan Planning Organization for the Bay Area, adopted the Plan Bay Area in July 2017 (ABAG and MTC 2017). The Plan Bay Area is a long-range plan for transportation projects within the planning area and established 13 performance targets to achieve the following goals/outcomes: Climate Protection, Adequate Housing, Healthy and Safe Communities, Open Space and Agricultural Preservation, Equitable Access, Economic Vitality, and Transportation System Effectiveness. Two of these targets are mandatory to comply with SB 375, and the Plan Bay Area exceeds the 15% reduction per capita in GHG emissions from light-trucks and cars by 2035 (Climate Protection Goal), and plans to house 100% of the region’s projected growth (from a 2010 baseline year) by income level without displacing current low-income residents and with no increase in in-commuters (Adequate Housing Goal).

Agenda Item #6.2.

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Advanced Clean Cars Program. In January 2012, CARB approved the Advanced Clean Cars program, an emissions-control program for model years 2015 through 2025. The program combines the control of smog- and soot-causing pollutants and GHG emissions into a single, coordinated package. The package includes elements to reduce smog-forming pollution, reduce GHG emissions, promote clean cars, and provide the fuels for clean cars (CARB 2011b). To improve air quality, CARB implemented new emission standards to reduce smog-forming emissions beginning with 2015 model-year vehicles. It is estimated that by 2025, cars will emit 75% less smog-forming pollution than the average new car sold before 2012. To reduce GHG emissions, CARB, in conjunction with the EPA and NHTSA, adopted new GHG standards for model years 2017 to 2025 vehicles; the new standards are estimated to reduce GHG emissions by 34% by 2025. The Zero Emissions Vehicle (ZEV) Program will act as the focused technology of the Advanced Clean Cars program by requiring manufacturers to produce increasing numbers of ZEVs and plug-in hybrid electric vehicles in 2018 to 2025 model years. The Clean Fuels Outlet regulation will ensure that fuels such as electricity and hydrogen are available to meet the fueling needs of the new advanced technology vehicles as they come to the market.

EO B-16-12. EO B-16-12 (2012) directs state entities under the governor’s direction and control to support and facilitate development and distribution of ZEVs. This executive order also sets a long-term target of reaching 1.5 million ZEVs on California’s roadways by 2025. On a statewide basis, EO B-16-12 also establishes a GHG emissions reduction target from the transportation sector equaling 80% less than 1990 levels by 2050. In furtherance of this executive order, the governor convened an Interagency Working Group on ZEVs that has published multiple reports regarding the progress made on the penetration of ZEVs in the statewide vehicle fleet.

AB 1236. AB 1236 (2015), as enacted in California’s Planning and Zoning Law, requires local land use jurisdictions to approve applications for the installation of electric vehicle charging stations, as defined, through the issuance of specified permits unless there is substantial evidence in the record that the proposed installation would have a specific, adverse impact on public health or safety, and there is no feasible method to satisfactorily mitigate or avoid the specific, adverse impact. The bill provides for appeal of that decision to the planning commission. The bill required local land use jurisdictions with a population of 200,000 or more residents to adopt an ordinance, by September 30, 2016, to create an expedited and streamlined permitting process for electric vehicle charging stations.

Solid Waste
AB 939 and AB 341. In 1989, AB 939, known as the Integrated Waste Management Act (PRC Sections 40000 et seq.), was passed because of the increase in waste stream and decrease in landfill capacity. The statute established the California Integrated Waste Management Board, which oversees a disposal reporting system. AB 939 mandated a reduction of waste being Agenda Item #6.2.

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disposed of, and jurisdictions were required to meet diversion goals of all solid waste through source reduction, recycling, and composting activities of 25% by 1995 and 50% by 2000.

AB 341 (2011) amended the California Integrated Waste Management Act of 1989 to include a provision declaring that it is the policy goal of the state that not less than 75% of solid waste generated be source-reduced, recycled, or composted by 2020, and annually thereafter. In addition, AB 341 required the California Department of Resources Recycling and Recovery (CalRecycle) to develop strategies to achieve the state’s policy goal. CalRecycle has conducted multiple workshops and published documents that identify priority strategies that CalRecycle believes will assist the state in reaching the 75% goal by 2020.

Water
EO B-29-15. In response to the ongoing drought in California, EO B-29-15 (April 2015) set a goal of achieving a statewide reduction in potable urban water usage of 25% relative to water use in 2013. The term of the executive order extended through February 28, 2016, although many of the directives have since become permanent water-efficiency standards and requirements. The executive order includes specific directives that set strict limits on water usage in the state. In response to EO B-29-15, the California Department of Water Resources modified and adopted a revised version of the Model Water Efficient Landscape Ordinance that, among other changes, significantly increased the requirements for landscape water use efficiency and broadened its applicability to include new development projects with smaller landscape areas.

EO B-37-16. Issued May 2016, EO B-37-16 directed the State Water Resources Control Board to adjust emergency water conservation regulations through the end of January 2017 to reflect differing water supply conditions across the state. The State Water Resources Control Board also developed a proposal to achieve a mandatory reduction of potable urban water usage that builds off the mandatory 25% reduction called for in EO B-29-15. The State Water Resources Control Board and Department of Water Resources will develop new, permanent water use targets that build upon the existing state law requirements that the state achieve 20% reduction in urban water usage by 2020. EO B-37-16 also specifies that the State Water Resources Control Board permanently prohibit water-wasting practices such as hosing off sidewalks, driveways, and other hardscapes; washing automobiles with hoses not equipped with a shut-off nozzle; using non-recirculated water in a fountain or other decorative water feature; watering lawns in a manner that causes runoff, or within 48 hours after measurable precipitation; and irrigating ornamental turf on public street medians.

Agenda Item #6.2.

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Other State Regulations and Goals
SB 97. SB 97 (Dutton) (August 2007) directed the Governor’s Office of Planning and Research (OPR) to develop guidelines under CEQA for the mitigation of GHG emissions. In 2008, the OPR issued a technical advisory as interim guidance regarding the analysis of GHG emissions in CEQA documents. The advisory indicated that the lead agency should identify and estimate a project’s GHG emissions, including those associated with vehicular traffic, energy consumption, water usage, and construction activities (OPR 2008). The advisory further recommended that the lead agency determine significance of the impacts and impose all mitigation measures necessary to reduce GHG emissions to a level that is less than significant. The CNRA adopted the CEQA Guidelines amendments in December 2009, which became effective in March 2010.

Under the amended CEQA Guidelines in the California Code of Regulations (CCR), a lead agency has the discretion to determine whether to use a quantitative or qualitative analysis, or apply performance standards to determine the significance of GHG emissions resulting from a particular project (14 CCR 15064.4(a)). The CEQA Guidelines require a lead agency to consider the extent to which a project complies with regulations or requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions (14 CCR 15064.4(b)). The CEQA Guidelines also allow a lead agency to consider feasible means of mitigating the significant effects of GHG emissions, including reductions in emissions through implementation of project features or offsite measures. The adopted amendments do not establish a GHG emissions threshold, but allow a lead agency to develop, adopt, and apply its own thresholds of significance or those developed by other agencies or experts. The CNRA also acknowledges that a lead agency may consider compliance with regulations or requirements implementing AB 32 in determining the significance of a project’s GHG emissions (CNRA 2009a).

With respect to GHG emissions, the CEQA Guidelines state in CCR Section 15064.4(a) that lead agencies should “make a good faith effort, to the extent possible on scientific and factual data, to describe, calculate or estimate” GHG emissions. The CEQA Guidelines note that an agency may identify emissions by either selecting a “model or methodology” to quantify the emissions, or by relying on “qualitative analysis or other performance-based standards” (14 CCR 15064.4(a)). Section 15064.4(b) states that the lead agency should consider the following when assessing the significance of impacts from GHG emissions on the environment: the extent a project may increase or reduce GHG emissions compared to the existing environmental setting; whether project emissions exceed a threshold of significance that the lead agency determines applies to the project; and the extent to which the project complies with regulations or requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions (14 CCR 15064.4(b)).

Agenda Item #6.2.

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EO S-13-08 (November 2008) is intended to hasten California’s response to the impacts of global climate change, particularly sea-level rise. Therefore, the executive order directs state agencies to take specified actions to assess and plan for such impacts. The final 2009 California Climate Adaptation Strategy report was issued in December 2009 (CNRA 2009a), and an update, Safeguarding California: Reducing Climate Risk, followed in July 2014 (CNRA 2014).

To assess the state’s vulnerability to climate change, the report summarizes key climate change impacts to the state for the following areas: agriculture, biodiversity and habitat, emergency management, energy, forestry, ocean and coastal ecosystems and resources, public health, transportation, and water. Issuance of updated Safeguarding California plans followed in March 2016 (CNRA 2016) and in January 2018 (CNRA 2018).
2015 State of the State Address and the 2016 State of the State Address. In January 2015, Governor Brown in his inaugural address and annual report to the Legislature established supplementary goals that would further reduce GHG emissions over the next 15 years. These goals include an increase in California’s renewable energy portfolio from 33% to 50%, a reduction in vehicle petroleum use for cars and trucks by up to 50%, measures to double the efficiency of existing buildings, and measures to decrease emissions associated with heating fuels. In his January 2016 address, Governor Brown established a statewide goal to bring percapita GHG emissions down to 2 MT per person, which reflects the goal of the Global Climate Leadership Memorandum of Understanding (Under 2 Memorandum of Understanding) to limit global warming to less than 2°C by 2050. The Under 2 Memorandum of Understanding agreement pursues emission reductions of 80% to 95% below 1990 levels by 2050 and/or reach a per-capita annual emissions goal of less than 2 MT by 2050. A total of 187 jurisdictions representing 38 countries and six continents, including California, have signed or endorsed the Under 2 Memorandum of Understanding (Under 2 Coalition 2017). As of 2019, Governor Newsom has not enacted any such changes to the state’s GHG reduction goals.

Local Regulations
City of St. Helena 1993 General Plan
The Land Use and Growth Management, Transportation, Public Health and Safety, and Public Facilities and Services Elements of the City of St. Helena 1993 General Plan (City of St. Helena 1993) provides the following guiding policies related to reducing GHG emissions:

Policy 2.6.21: Require new residential projects to be designed to facilitate nonautomobile modes of travel (i.e., walking, biking, transit, etc.).

Policy 5.8.1: All new development on collector streets shall provide sidewalks or walkways to be located with the City’s right-of-way for the collector street. Further, Agenda Item #6.2.

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unless exempted or deferred by the City Council, all residential developments shall provide sidewalks on all local streets within the development. • It is a goal of the City that it continue to remain at a size where the majority of development is within a 10 minute walk of the downtown. Sidewalks or walkways will reinforce the pedestrian orientation of the City.

Policy 8.2.5: Support a population and employment growth policy which will not exceed ABAG population and employment projections. This includes balancing the ratio of employment to population to protect, preserve and enhance the air quality within the area.

Policy 9.2.3: Adopt and implement water conservation measures as a means of extending the capabilities of the City’s water supply.
• Adoption of a Toilet Retrofit Ordinance to convert high-use fixtures to low-flow fixtures and a Water-Efficient Landscape Ordinance to require water-conserving xeriscapes could increase the number of available water connections. It is estimated that 1600 residential units could be converted to low-flow fixtures saving about 50 acre-feet of water per year which could service 125 units.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The Land Use and Growth Management, Public Health and Safety, and Climate Change Elements of the City of St. Helena 2019 General Plan (City of St. Helena 2019) provide policies regarding GHG emissions, including the following:

Policy LU2.7: Ensure safe, walkable, and bikeable residential neighborhoods and vibrant, livable streets.

Policy PS1.3: Encourage effective regulation of those sources of air pollution, both inside and outside of St. Helena, which affect air quality, by implementing as many of the recommendations of the Napa County Congestion Management Plan as is feasible.

Policy CC1.1: Promote a “walkable” and “bikeable” city.

Policy CC2.1: Encourage measures to reduce energy demand through conservation and efficiency.

Policy CC2.2: Support local efforts to improve the energy supply by switching from fossil fuels to renewables.

Agenda Item #6.2.

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Policy CC4.3: Strengthen water conservation measures that result in significant reductions in local water use and the protection of local water resources.

3.7.4 Impacts
Methods of Analysis
GHG emissions from construction and operation of the Proposed Project were calculated using CalEEMod Version 2016.3.2. Details relevant to the modeling assumptions is described below.

Construction
Construction model inputs are described in more detail in Section 3.3, Air Quality, of this Environmental Impact Report. In summary, the Proposed Project was assumed to be constructed over a 6-year buildout.

Operations
Operational GHG emissions were estimated for buildout of the Proposed Project. The first full year of operation was assumed to be 2029, which is based on the completion of all construction activities.

Area Sources
CalEEMod was used to estimate GHG emissions from the Proposed Project’s area sources, including operation of landscape maintenance equipment, which produces minimal GHG emissions. See Section 3.3, Air Quality, for a discussion of landscaping equipment emissions calculations. Consumer product use and architectural coatings result in volatile organic compound emissions, which are analyzed as part of the air quality analysis.

Energy Sources
As represented in CalEEMod, energy sources include emissions associated with building electricity and natural gas usage (non-hearth). The estimation of operational energy emissions was based on CalEEMod land use defaults and units or total area (i.e., square footage) of the proposed residential land use. The 2019 Title 24 standards were approved and adopted by the California Building Standards Commission in December 2018. The 2019 standards became effective January 1, 2020. CalEEMod uses the 2016 version of Title 24 as a basis for energy modeling, however this analysis reflects compliance with the 2019 standards. Per the CEC Impact Analysis for the 2019 Update to the California Energy Efficiency Standards for Residential and Non-Residential Buildings, the first-year savings for newly constructed singlefamily residences, are 596 gigawatt hours of electricity, 50.4 megawatts of demand, and 4.42 Agenda Item #6.2.

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million therms of gas, representing reductions from the 2016 Title 24 standard of 4% of electricity, 15% of demand, and 9% of natural gas, respectively. The first-year savings for lowrise multifamily buildings are 91 gigawatt hours, 4.1 megawatts of demand, and 0.25 million therms of gas. On a percent savings basis compared to the 2016 standards, the multifamily, savings are 2% of electricity, 8% of demand and 5% of gas.

Emissions were calculated by multiplying the energy use by the utility carbon intensity (pounds of GHGs per kilowatt-hour for electricity or 1,000 British thermal units for natural gas) for CO2 and other GHGs. Annual natural gas (non-hearth) and electricity emissions were estimated in CalEEMod using the default emissions factors for the proposed land uses.

Two electricity service providers would be available to provide service to the Proposed Project.

The Marin Clean Energy, which is a community choice aggregation program and Pacific Gas & Electric (PG&E). While residents within the City are automatically enrolled into Marin Clean Energy, an individual can opt out and choose PG&E for electricity service. As discussed under the Regulatory Setting in Section 3.3, SB X1 2 established a target of 33% from renewable energy sources for all electricity providers in California by 2020. Marin Clean Energy provides a higher percentage of electricity from renewable sources than PG&E; however, this analysis is based on the lower RPS or conservative estimate in order to estimate the Proposed Project’s GHG emissions. Therefore, the CO2 emissions intensity factor for utility energy use in CalEEMod was adjusted consistent with the PG&E 2020 Corporate Responsibility and Sustainability Report, which reported that PG&E has delivered 30% of the electricity from RPS eligible resources and has emissions rate of 206 pounds of CO2 per megawatt-hour (PG&E 2020).

Mobile Sources
Mobile sources for the Proposed Project would primarily be motor vehicles traveling to and from the Project site. The anticipated trip generation, including the trip rates and total trips, are based on the Proposed Project’s Traffic Impact Study prepared by Dudek (see Appendix K).

CalEEMod was used to calculate the emissions resulting from on-road mobile sources associated with residents traveling to and from the proposed land use types.

Default trip generation rates included in CalEEMod for each analyzed proposed land uses were adjusted to match the Proposed Project’s trip generation. In addition, Saturday and Sunday trip rates were adjusted based on the CalEEMod default trip rates and the Proposed-Projectspecific trip rates presented in the traffic study. The CalEEMod default and assumed trip rates are depicted in Table 3.7-4.

Agenda Item #6.2.

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Table 3.7-4
CalEEMod Default and Adjusted Trip Rates
Land Use Type Size Metric
CalEEMod Default Vehicle Trip
Rates
Proposed Project Vehicle Trip
Rates1
Weekday
Trip Rate
Saturday
Trip Rate
Sunday
Trip Rate
Weekday
Trip Rate
Saturday
Trip Rate
Sunday
Trip
Rate
Single-Family Residential Dwelling Unit 9.52 9.91 8.62 9.44 9.56 8.31 Accessory Dwelling Units Dwelling Unit 6.59 7.16 6.07 7.36 8.18 6.94 Multi-Family Units Dwelling Unit 5.81 5.67 4.84 9.44 9.56 8.31 Note:
1 Weekday trip rates were provided in the Proposed Project’s Traffic Impact Study. Proposed Project Saturday and Sunday trips rates were adjusted based on the ratio of the CalEEMod default Saturday and Sunday trip rates to the CalEEMod default weekday trip rate.

Sources: CAPCOA 2017; Dudek 2020.

Solid Waste
The Proposed Project would generate solid waste, and therefore, result in CO2e emissions associated with landfill off-gassing. CalEEMod default values for solid waste generation were used to estimate GHG emissions associated with solid waste.

Water and Wastewater
Supply, conveyance, treatment, and distribution of water to serve the Proposed Project requires the use of electricity, which would result in associated indirect GHG emissions. Similarly, wastewater generated by the Proposed Project requires the use of electricity for conveyance and treatment, along with GHG emissions generated during wastewater treatment. Water consumption estimates for indoor use were based on data provided within the Preliminary Water Calculations Technical Memorandum (RSA 2019). The total water demand for each land use type as provided in the memorandum were allocated based on the default proportions from CalEEMod’s indoor water use. Water consumption for outdoor water use were estimated for the Proposed Project using CalEEMod default values.

Thresholds of Significance
Consistent with Appendix G of the CEQA Guidelines, a significant impact would occur if development of the Proposed Project would do any of the following:
• Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment.
• Conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases.

Agenda Item #6.2.

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Regarding impacts from GHGs, both BAAQMD and the California Air Pollution Control Officers Association consider GHG impacts to be exclusively cumulative impacts (BAAQMD 2017; CAPCOA 2008); therefore, assessment of significance is based on a determination of whether the GHG emissions from a project represent a cumulatively considerable contribution to the global atmosphere. This analysis uses both a quantitative and a qualitative approach. The quantitative approach is used to address the first significance criterion: “Would the project generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment?” This analysis considers that, because the quantifiable thresholds developed by BAAQMD were formulated based on AB 32 and California Climate Change Scoping Plan reduction targets for which its set of strategies were developed to reduce GHG emissions statewide, a project cannot exceed a numeric BAAQMD threshold without also conflicting with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of GHGs. Therefore, if a project exceeds a numeric threshold and results in a significant cumulative impact, it would also result in a significant cumulative impact with respect to plan, policy, or regulation consistency, even though the project may incorporate measures and have features that would reduce its contribution to cumulative GHG emissions.

Separate thresholds of significance have been established by the BAAQMD for operational emissions from stationary sources (such as generators, furnaces, and boilers) and nonstationary sources (such as on-road vehicles) (BAAQMD 2017). The threshold for stationary sources is 10,000 MT CO2e per year (i.e., emissions above this level may be considered significant). For nonstationary sources, the following three separate thresholds have been established:
• Compliance with a Qualified Greenhouse Gas Reduction Strategy (i.e., if a project is found to be out of compliance with a Qualified Greenhouse Gas Reduction Strategy, its GHG emissions may be considered significant).
• 1,100 MT CO2e per year (i.e., emissions above this level may be considered significant). • 4.6 MT CO2e per service population per year (i.e., emissions above this level may be considered significant). (Service population is the sum of residents plus employees expected for a development project.)
The quantitative threshold of 1,100 MT CO2e annually adopted by BAAQMD is applied to this analysis. If a proposed project’s GHG emissions would exceed this threshold then, consistent with BAAQMD Guidelines, it would be considered to have a cumulatively considerable contribution of GHG emissions and a cumulatively significant impact on climate change.

Agenda Item #6.2.

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Impacts and Mitigation Measures

3.7-1: Would the Proposed Project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? This impact would be less than significant.

Construction
Construction of the proposed residences along with site clearing, grading and installation of utilities would result in GHG emissions, which are primarily associated with use of off-road construction equipment, vendor trucks, and worker vehicles. Since the BAAQMD has not established construction-phase GHG thresholds, construction GHG emissions were amortized assuming a 30-year development life after completion of construction and were compared to the BAAQMD operational GHG threshold. Amortized GHG emissions associated with Proposed Project construction would result in annualized generation of 17 MT CO2e.

A detailed depiction of the construction schedule—including information regarding phasing, equipment used during each phase, trucks, and worker vehicles—is included in Appendix C. The estimated Proposed-Project-generated GHG emissions from construction activities assuming a 6- year buildout are shown in Table 3.7-5. The 6-year buildout assumes that building construction activities would be spread out over a 6-year period, occurring on average for approximately 7 months per year. Although, the construction duration could be spread out over a 6-year period, site preparation/grading/utility work would occur during the first phase of construction.

Table 3.7-5
Estimated Annual Construction Greenhouse Gas Emissions – 6-Year Buildout Emission Source/Year CO2e (MT/yr)
2023 287.9
2024 225.1
2025 302.9
2026 255.0
2027 219.4
2028 200.1
Total 1,490.4
Amortized Construction Emissions 49.7
Notes: Total emissions may not sum due to rounding.

CO2e = carbon dioxide-equivalent; MT/year = metric tons per year Source: See Appendix C for detailed results.

Operations
Following the completion of construction activities, the Proposed Project would generate GHG emissions from mobile sources (vehicle trips), area sources (landscaping equipment), energy Agenda Item #6.2.

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sources (natural gas and electricity consumption), solid waste generation, water supply, and wastewater treatment. The estimated operational Proposed-Project-generated GHG these sources are shown in Table 3.7-6.

Table 3.7-6
Estimated Annual Operational Greenhouse Gas Emissions
Proposed Project Emission Source CO2e (MT/yr)
Area 12.0
Energy 158.3
Mobile 549.2
Solid Waste 34.9
Water Supply and Wastewater 10.6
Total 765.0
Amortized Construction Emissions 49.7
Operation + Amortized Construction Total 814.7
BAAQMD GHG Threshold 1,100
Significant (Yes or No)? No
Note: CO2e = carbon dioxide-equivalent; MT/year = metric tons per year Source: See Appendix C for detailed results.

Table 3.7-6 indicates that the GHG emissions associated with development of the Proposed Project would be below BAAQMD’s GHG threshold of 1,100 MT CO2e per year. Therefore, the Proposed Project would not generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment, and this would represent a cumulatively less-thansignificant GHG impact.

Mitigation Measures
None required.

3.7-2: Would the Proposed Project conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases? This impact would be less than significant.

The City is currently in the process of developing a GHG Reduction Plan and a Climate Action Plan, which would include various GHG reduction measures that would help the City reduce communitywide GHG emissions. Thus, the City does not have an adopted plan that would be applicable to the Proposed Project. However, consistency with other plans including the Plan Bay Area, Scoping Plan, and future GHG reduction goals are described below.

Agenda Item #6.2.

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ABAG and Metropolitan Transportation Commission’s Plan Bay Area The Plan Bay Area is a regional growth management strategy that targets per capita GHG reduction from passenger vehicles and light-duty trucks for the San Francisco Bay Area (ABAG and MTC 2017). The Plan Bay Area is not directly applicable to the Proposed Project because the underlying purpose of the Plan Bay Area is to provide direction and guidance on future regional growth (i.e., the location of new residential and non-residential land uses) and transportation patterns throughout the region, as stipulated under SB 375. Within the Plan Bay Area, the core strategy includes “focused growth” in existing communities along existing transportation networks. The key to implementing the focused growth strategy are Priority Development Areas and Priority Conservative Areas. In addition, the Metropolitan Transportation Commission and the ABAG Executive Board established seven goals and 13 performance targets to measure Plan Bay Area 2040’s effectiveness in addressing the major challenges facing the region. Development of the Project site would support the overarching intent of the Plan Bay Area through developing residential land uses including a component dedicated for affordable housing, which would help the region attain its adequate housing targets. Therefore, the Proposed Project would generally be considered consistent with applicable goals and strategies set forth in the Plan Bay Area.

CARB’s Scoping Plan
As discussed above in Section 3.7.3, the Scoping Plan (approved by CARB in 2008 and updated in 2014 and 2017) provides a framework for actions to reduce California’s GHG emissions and requires CARB and other state agencies to adopt regulations and other initiatives to reduce GHGs. The Scoping Plan is not directly applicable to specific projects, nor is it intended to be used for project-level evaluations.3 Under the Scoping Plan, however, there are several state regulatory measures aimed at the identification and reduction of GHG emissions.

CARB and other state agencies have adopted many of the measures identified in the Scoping Plan. Most of these measures focus on area source emissions (e.g., energy usage, high-GWP GHGs in consumer products) and changes to the vehicle fleet (i.e., hybrid, electric, and more fuel-efficient vehicles) and associated fuels (e.g., Low-Carbon Fuel Standard), among others.

The Scoping Plan recommends strategies for implementation at the statewide level to meet the goals of AB 32 and establishes an overall framework for the measures that will be adopted to reduce California’s GHG emissions. Table 3.7-7 highlights measures that have been, or will be, developed under the Scoping Plan and the Proposed Project’s consistency with Scoping Plan 3 The Final Statement of Reasons for the amendments to the State CEQA Guidelines reiterates the statement in the Initial Statement of Reasons that “[t]he Scoping Plan may not be appropriate for use in determining the significance of individual projects because it is conceptual at this stage and relies on the future development of regulations to implement the strategies identified in the Scoping Plan” (CNRA 2009b).

Agenda Item #6.2.

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measures. To the extent that these regulations are applicable to the Proposed Project, its inhabitants, or uses, the Proposed Project would comply with all regulations adopted in furtherance of the Scoping Plan to the extent required by law.

Table 3.7-7
Proposed Project Consistency with Scoping Plan
Greenhouse Gas Emission Reduction Strategies
Scoping Plan Measure
Measure
Number Proposed Project Consistency
Transportation Sector
Advanced Clean Cars T-1 Consistent. Proposed Project residents and visitors would purchase vehicles in compliance with CARB vehicle standards that are in effect at the time of vehicle purchase.

Low-Carbon Fuel Standard T-2 Consistent. Motor vehicles driven by Proposed Project residents and visitors would use compliant fuels.

Regional Transportation-Related GHG
Targets
T-3 Consistent. The Project site is located near transit services (VINE Transit) which would reduce dependence on passenger vehicle trips and shorter trip lengths, which would reduce GHG emissions.

Advanced Clean Transit Proposed Not applicable.

Last-Mile Delivery Proposed Not applicable.

Reduction in VMT Proposed Not applicable.

Vehicle Efficiency Measures
Tire Pressure
Fuel Efficiency Tire Program
Low-Friction Oil
Solar-Reflective Automotive Paint and
Window Glazing
T-4 Consistent. It is assumed motor vehicles driven by Proposed Project residents and visitors would maintain proper tire pressure when their vehicles are serviced. Replacement tires and low-friction oil would be used in compliance with CARB vehicle standards that are in effect at the time of vehicle or tire purchase.

Ship Electrification at Ports (Shore Power) T-5 Not applicable.

Goods Movement Efficiency Measures
Port Drayage Trucks
Transport Refrigeration Units Cold Storage
Prohibition
Cargo Handling Equipment, Anti-Idling,
Hybrid, Electrification
Goods Movement Systemwide Efficiency
Improvements
Commercial Harbor Craft Maintenance and
Design Efficiency
Clean Ships
Vessel Speed Reduction
T-6 Not applicable.

Heavy-Duty Vehicle GHG Emission
Reduction
Tractor-Trailer GHG Regulation
Heavy-Duty Greenhouse Gas Standards for
New Vehicle and Engines (Phase I)
T-7 Not applicable.

Agenda Item #6.2.

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Table 3.7-7
Proposed Project Consistency with Scoping Plan
Greenhouse Gas Emission Reduction Strategies
Scoping Plan Measure
Measure
Number Proposed Project Consistency
Medium- and Heavy-Duty Vehicle
Hybridization Voucher Incentive Proposed
Project
T-8 Not applicable.

Medium and Heavy-Duty GHG Phase 2 Proposed Not applicable.

High-Speed Rail T-9 Not applicable.

Electricity and Natural Gas Sector
Energy Efficiency Measures (Electricity) E-1 Consistent. The Proposed Project will comply with current Title 24, Part 6, of the California Code of Regulations energy efficiency standards.

Energy Efficiency (Natural Gas) CR-1 Not applicable.

Solar Water Heating (California Solar
Initiative Thermal Program)
CR-2 Not applicable.

Combined Heat and Power E-2 Not applicable.

Renewable Portfolios Standard (33% by
2020)
E-3 Consistent. The electricity used by the Proposed Project would benefit from reduced GHG emissions resulting from increased use of renewable energy sources.

Renewable Portfolios Standard (50% by
2050)
Proposed Consistent. The electricity used by the Proposed Project would benefit from reduced GHG emissions resulting from increased use of renewable energy sources.

SB 1 Million Solar Roofs
(California Solar Initiative, New Solar Home
Partnership, Public Utility Programs) and
Earlier Solar Programs
E-4 Consistent. The Proposed Project would be required to implement on-site generation of renewable energy using solar panels on available rooftop space to offset a portion of the Proposed Project’s electricity consumption as mandated by the California Building Standards Commission. However,
specifications regarding the size of rooftop solar is currently unknown.

Water Sector
Water Use Efficiency W-1 Consistent. The Proposed Project would be required to comply with statewide water conservation requirements reducing water usage by 20%. Furthermore, low-flow plumbing equipment
would be installed including waterless urinals, two flush toilets, and automated restroom faucets, in compliance with state building codes.

Water Recycling W-2 Not applicable. Recycled water is not available to the site.

Water System Energy Efficiency W-3 Not applicable. This is applicable for the transmission and treatment of water but is not applicable to the Proposed Project.

Reuse Urban Runoff W-4 Not applicable. The Proposed Project would not reuse urban water on-site.

Renewable Energy Production W-5 Not applicable. This is applicable for wastewater treatment systems but is not applicable to the Proposed Project.

Agenda Item #6.2.

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Table 3.7-7
Proposed Project Consistency with Scoping Plan
Greenhouse Gas Emission Reduction Strategies
Scoping Plan Measure
Measure
Number Proposed Project Consistency
Green Buildings
State Green Building Initiative: Leading the
Way with State Buildings (Greening New and
Existing State Buildings)
GB-1 Not applicable.

Green Building Standards Code (Greening
New Public Schools, Residential and
Commercial Buildings)
GB-1 Consistent. The Proposed Project would be required to meet green building standards that are in effect at the time of design and construction.

Beyond Code: Voluntary Programs at the
Local Level (Greening New Public Schools,
Residential and Commercial Buildings)
GB-1 Consistent. The Proposed Project would be required to be constructed in compliance with local green building standards in effect at the time of building construction.

Greening Existing Buildings (Greening
Existing Homes and Commercial Buildings)
GB-1 Not applicable. This is applicable for existing buildings only. It is not applicable for the Proposed Project except as future standards may become applicable to existing buildings.

Industry Sector
Energy Efficiency and Co-Benefits
Audits for Large Industrial Sources
I-1 Not applicable.

Oil and Gas Extraction GHG Emission
Reduction
I-2 Not applicable.

Reduce GHG Emissions by 20% in Oil
Refinery Sector
Proposed Not applicable.

GHG Emissions Reduction from Natural Gas
Transmission and Distribution
I-3 Not applicable.

Refinery Flare Recovery Process
Improvements
I-4 Not applicable.

Work with the local air districts to evaluate
amendments to their existing leak detection
and repair rules for industrial facilities to
include methane leaks
I-5 Not applicable.

Recycling and Waste Management Sector
Landfill Methane Control Measure RW-1 Not applicable.

Increasing the Efficiency of Landfill Methane
Capture
RW-2 Not applicable.

Mandatory Commercial Recycling RW-3 Consistent. During both construction and operation, the Proposed Project would be required to comply with all state regulations related to solid waste generation, storage, and disposal, including the California Integrated Waste Management Act, as amended. During construction, all wastes would be recycled to the maximum extent possible.

Increase Production and Markets for
Compost and Other Organics
RW-3 Not applicable.

Anaerobic/Aerobic Digestion RW-3 Not applicable.

Extended Producer Responsibility RW-3 Not applicable (applicable to product designer and producers).

Agenda Item #6.2.

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Table 3.7-7
Proposed Project Consistency with Scoping Plan
Greenhouse Gas Emission Reduction Strategies
Scoping Plan Measure
Measure
Number Proposed Project Consistency
Environmentally Preferable Purchasing RW-3 Not applicable (applicable to product designer and producers).

Forests Sector
Sustainable Forest Target F-1 Not applicable.

High GWP Gases Sector
Motor Vehicle Air Conditioning Systems:

Reduction of Refrigerant Emissions from
Non-Professional Servicing
H-1 Consistent. Proposed Project residents would be prohibited from performing air conditioning repairs and would be required to use professional servicing.

SF6 Limits in Non-Utility and NonSemiconductor ApplicationsH-2 Not applicable.

Reduction of Perfluorocarbons (PFCs in
Semiconductor Manufacturing
H-3 Not applicable.

Limit High GWP Use in Consumer Products H-4 Consistent. The Proposed Project would use consumer products that would comply with the regulations that are in effect at the time of manufacture.

Air Conditioning Refrigerant Leak Test
During Vehicle Smog Check
H-5 Consistent. It is assumed motor vehicles driven by Proposed Project residents would comply with the leak test requirements during smog checks.

Stationary Equipment Refrigerant
Management Program – Refrigerant
Tracking/Reporting/Repair Program
H-6 Not applicable.

Stationary Equipment Refrigerant
Management Program – Specifications for
Commercial and Industrial Refrigeration
H-6 Not applicable.

SF6 Leak Reduction Gas Insulated
Switchgear
H-6 Not applicable.
40% reduction in methane and
hydrofluorocarbon (HFC) emissions
Proposed Not applicable.
50% reduction in black carbon emissions Proposed Not applicable.

Agriculture Sector
Methane Capture at Large Dairies A-1 Not applicable. The Proposed Project would not prevent CARB from implementing this measure.

Notes: CARB = California Air Resources Board; CCR = California Code of Regulations; GHG = greenhouse gas; GWP = global warming potential; SB = Senate Bill; SF6 = sulfur hexafluoride
Sources: CARB 2008, 2017a.

Based on the analysis in Table 3.7-7, the Proposed Project would be considered consistent with the applicable strategies and measures in the CARB Scoping Plan.

SB 32 and EO S-3-05
Regarding consistency with SB 32 (goal of reducing GHG emissions to 40% below 1990 levels by 2030) and EO S-3-05 (goal of reducing GHG emissions to 80% below 1990 levels by 2050), Agenda Item #6.2.

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there are no established protocols or thresholds of significance for that future-year analysis.

However, CARB has expressed optimism regarding the 2030 and 2050 goals. It states in the First Update that “California is on track to meet the near-term 2020 GHG emissions limit and is well positioned to maintain and continue reductions beyond 2020 as required by AB 32” (CARB 2014). Regarding the 2050 target for reducing GHG emissions to 80% below 1990 levels, the First Update states the following (CARB 2014):

This level of reduction is achievable in California. In fact, if California realizes the expected benefits of existing policy goals (such as 12,000 megawatts of renewable distributed generation by 2020, net zero energy homes after 2020, existing building retrofits under Assembly Bill 758, and others) it could reduce emissions by 2030 to levels squarely in line with those needed in the developed world and to stay on track to reduce emissions to 80% below 1990 levels by 2050. Additional measures, including locally driven measures and those necessary to meet federal air quality standards in 2032, could lead to even greater emission reductions.

In other words, CARB believes that the state is on a trajectory to meet the 2030 and 2050 GHG reduction targets set forth in AB 32, SB 32, and EO S-3-05. This is confirmed in the Second Update, which states, “[t]his Plan draws from the experiences in developing and implementing previous plans to present a path to reaching California’s 2030 GHG reduction target. The Plan is a package of economically viable and technologically feasible actions to not just keep California on track to achieve its 2030 target, but stay on track for a low- to zero-carbon economy by involving every part of the state” (CARB 2017a). The Second Update also states that although “the Scoping Plan charts the path to achieving the 2030 GHG emissions reduction target, we also need momentum to propel us to the 2050 statewide GHG target (80% below 1990 levels).

In developing this Scoping Plan, we considered what policies are needed to meet our mid-term and long-term goals” (CARB 2017a).

As discussed previously, the Proposed Project would be considered consistent with the Plan Bay Area and CARB’s 2017 Scoping Plan and would not conflict with the state’s trajectory toward meeting future GHG reductions. Since the specific path to compliance for the state in regards to the long-term goals would likely require development of technology or other changes that are not currently known or available, specific additional mitigation measures for the Proposed Project would be speculative and cannot be identified at this time. With respect to future GHG targets under SB 32 and EO S-3-05, CARB made clear in its legal interpretation that it has the requisite authority to adopt whatever regulations are necessary, beyond the AB 32 horizon year of 2020, to meet SB 32’s 40% reduction target by 2030 and EO S-3-05’s 80% reduction target by 2050; this legal interpretation by an expert agency provides evidence that future regulations would be adopted to continue the state on its trajectory toward meeting these future GHG targets.

Agenda Item #6.2.

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Based on the preceding considerations, the Proposed Project would not conflict with an applicable plan, policy, or regulation adopted to reduce the emissions of GHGs, and no mitigation is required. This impact would be less than significant.

Mitigation Measures
None required.

3.7.5 Cumulative Impacts
The geographic context for analyzing cumulative impacts is the San Francisco Bay Area Air Basin.

3.7-3: Would the Proposed Project contribute to cumulative GHG emissions within the region. The Project’s contribution would not be considerable.

GHG impacts are cumulative impacts (BAAQMD 2017; CAPCOA 2008); therefore, assessment of significance is based on a determination of whether the GHG emissions from a project represent a cumulatively considerable contribution to the global atmosphere. If a project exceeds the identified significance thresholds, its contribution of GHG emissions would be cumulatively considerable, resulting in a cumulatively significant impact on climate change. As discussed in Impact 3.7-1, the Proposed Project would not result in GHG emissions in exceedance of the BAAQMD significance threshold. Therefore, the Proposed Project’s GHG emissions would not be considered cumulatively considerable and the Proposed Project’s contribution would be less than significant.

Mitigation Measures
None required.

3.7.6 References
ABAG and MTC (Association of Bay Area Governments and Metropolitan Transportation Commission). 2017. Plan Bay Area: Regional Transportation Plan and Sustainable Communities Strategy for the San Francisco Bay Area 2017–2040. Adopted July 26, 2017. Accessed August 2018. http://2040.planbayarea.org/cdn/farfuture/ u_7TKELkH2s3AAiOhCyh9Q9QlWEZIdYcJzi2QDCZuIs/1510696833/sites/default/ files/2017-11/Final_Plan_Bay_Area_2040.pdf.

BAAQMD (Bay Area Air Quality Management District). 2017. California Environmental Quality Act Air Quality Guidelines. Updated May 2017. http://www.baaqmd.gov/~/media/files/ planning-and-research/ceqa/ceqa_guidelines_may2017-pdf.pdf?la=en.

Agenda Item #6.2.

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CAPCOA (California Air Pollution Control Officers Association). 2008. CEQA and Climate Change – Evaluating and Addressing Greenhouse Gas Emissions from Projects Subject to the California Environmental Quality Act. January 2008. http://www.energy.ca.gov/ 2008publications/CAPCOA-1000-2008-010/CAPCOA-1000-2008-010.PDF.

CAPCOA. 2017. California Emissions Estimator Model (CalEEMod) User’s Guide Version 2016.3.2. Prepared by BREEZE Software, A Division of Trinity Consultants in collaboration with South Coast Air Quality Management District and the California Air Districts. Accessed December 2017. http://www.aqmd.gov/docs/default-source/ caleemod/01_user-39-s-guide2016-3-2_15november2017.pdf?sfvrsn=4.

CARB (California Air Resources Board). 2008. Climate Change Scoping Plan: A Framework for Change. December 12, 2008. http://www.arb.ca.gov/cc/scopingplan/document/psp.pdf.

CARB. 2011a. Final Supplement to the AB 32 Scoping Plan Functional Equivalent Document.

Released August 19, 2011. https://www.arb.ca.gov/cc/scopingplan/document/ final_supplement_to_sp_fed.pdf.

CARB. 2011b. “Staff Report: Initial Statement of Reasons for Proposed Rulemaking, Public Hearing to Consider the ‘LEV III’ Amendments to the California Greenhouse Gas and Criteria Pollutant Exhaust and Evaporative Emission Standards and Test Procedures and to the On-Board Diagnostic System Requirements for Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles, and to the Evaporative Emission Requirements for Heavy-Duty Vehicles.” December 7, 2011. https://www.arb.ca.gov/regact/ 2012/leviiidtc12/dtcisor.pdf.

CARB. 2014. First Update to the Climate Change Scoping Plan: Building on the Framework Pursuant to AB 32 – The California Global Warming Solutions Act of 2006. May 2014.

Accessed August 2018. http://www.arb.ca.gov/cc/scopingplan/2013_update/ first_update_climate_change_scoping_plan.pdf.

CARB. 2016. “AB 32 Scoping Plan.” CARB Website Tracking Progress on the 2030 Scoping Plan Update. December 2, 2016.
https://www.arb.ca.gov/cc/scopingplan/scopingplan.htm.

CARB. 2017a. The 2017 Climate Change Scoping Plan Update: The Proposed Strategy for Achieving California’s 2030 Greenhouse Gas Target. January 20, 2017. Accessed January 2017. https://www.arb.ca.gov/cc/scopingplan/2030sp_pp_final.pdf.

CARB 2017b. “Glossary of Terms Used in GHG Inventories.” Last updated June 6, 2017. https://www.arb.ca.gov/cc/inventory/faq/ghg_inventory_glossary.htm.

Agenda Item #6.2.

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CARB. 2019. “California Greenhouse Gas Emission Inventory—2019 Edition.” August 12, 2019.

Accessed August 2019. http://www.arb.ca.gov/cc/inventory/data/data.htm.

CAT (Climate Action Team). 2010. Climate Action Team Biennial Report. Sacramento, California: CAT. April 2010. Accessed February 2014. http://www.energy.ca.gov/ 2010publications/CAT-1000-2010-004/CAT-1000-2010-004.PDF.

CCCC (California Climate Change Center). 2012. Our Changing Climate 2012: Vulnerability & Adaptation to the Increasing Risks from Climate Change in California. July 2012.

Accessed August 2016. http://www.energy.ca.gov/2012publications/CEC-500-2012- 007/CEC-500-2012-007.pdf.

CEC (California Energy Commission). 2018. 2019 Building Energy Efficiency Standards – Frequently Asked Questions.
https://www.energy.ca.gov/title24/2019standards/documents/2018_Title_24_2019_ Building_Standards_FAQ.pdf.

City of St. Helena. 1993. City of St. Helena 1993 General Plan. September 28, 1993.

City of St. Helena. 2018. St. Helena General Plan Update 2040 Draft Environmental Impact Report. October 23, 2018.

City of St. Helena. 2019. City of St. Helena General Plan Update 2040. June 2019.

CNRA (California Natural Resources Agency). 2009a. 2009 California Climate Adaptation Strategy: A Report to the Governor of the State of California in Response to Executive Order S-13-2008. http://resources.ca.gov/docs/climate/Statewide_ Adaptation_Strategy.pdf.

CNRA. 2009b. Final Statement of Reasons for Regulatory Action: Amendments to the State CEQA Guidelines Addressing Analysis and Mitigation of Greenhouse Gas Emissions Pursuant to SB 97. December 2009.

CNRA. 2014. Safeguarding California: Reducing Climate Risk: An Update to the 2009 California Climate Adaptation Strategy. July 2014. Accessed May 2017. http://resources.ca.gov/ docs/climate/Final_Safeguarding_CA_Plan_July_31_2014.pdf.

CNRA. 2016. Safeguarding California: Implementation Action Plans. March. Accessed May 2017. http://resources.ca.gov/docs/climate/safeguarding/Safeguarding%20CaliforniaImplementation%20Action%20Plans.pdf.

Agenda Item #6.2.

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CNRA. 2018. Safeguarding California Plan: 2018 Update: California’s Climate Adaptation Strategy. January 2018. Accessed October 2018. http://resources.ca.gov/docs/climate/ safeguarding/update2018/safeguarding-california-plan-2018-update.pdf.

CPUC (California Public Utilities Commission). 2013. “California’s Zero Net Energy Policies and Initiatives.” September 18, 2013. http://www.cpuc.ca.gov/WorkArea/ DownloadAsset.aspx?id=10718.

CPUC. 2015. Renewables Portfolio Standard. SB 350 Clean Energy and Pollution Reduction Act of 2015. Approved October 7, 2015.

EPA (U.S. Environmental Protection Agency). 2007. Energy Independence and Security Act of 2007. Accessed December 2016. https://www.gpo.gov/fdsys/pkg/BILLS-110hr6enr/ pdf/BILLS-110hr6enr.pdf.

EPA. 2016. “Glossary of Climate Change Terms.” August 9, 2016. Accessed August 2016. https://www3.epa.gov/climatechange/glossary.html.

EPA. 2017a. “Climate Change.” Last updated January 19, 2017. Accessed January 2017. https://www.epa.gov/climatechange.

EPA. 2017b. Carbon Pollution Standards for Cars and Light Trucks to Remain Unchanged Through 2025. January 13. Accessed February 2017. https://www.epa.gov/ newsreleases/carbon-pollution-standards-cars-and-light-trucks-remain-unchangedthrough-2025.

EPA. 2020. Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990–2018. EPA 430-R20-002. April 31, 2020. Accessed April 29, 2020.

EPA and NHTSA (Department of Transportation’s National Highway Traffic Safety Administration). 2016. Regulations and Standards: Heavy-Duty. EPA and DOT Finalize Greenhouse Gas and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Last updated on August 30, 2016. https://www.epa.gov/newsreleases/epaand-dot-finalize-greenhouse-gas-and-fuel-efficiency-standards-heavy-duty-trucks-0.

EPA and NHTSA. 2018. The Safer Affordable Fuel-Efficient 'SAFE' Vehicles Rule for Model Years 2021-2026 Passenger Vehicles and Light Trucks. Proposed Rule August 2018.

Accessed May 2019. https://www.govinfo.gov/content/pkg/FR-2018-08-24/pdf/2018- 16820.pdf.

EPA and NHTSA. 2019. The Safer Affordable Fuel-Efficient ‘SAFE’ Vehicles Rule Part One:

One National Program. Proposed Rule September 2019. Accessed December 2019. https://www.govinfo.gov/content/pkg/FR-2019-09-27/pdf/2019-20672.pdf.

Agenda Item #6.2.

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IPCC (Intergovernmental Panel on Climate Change). 1995. IPCC Second Assessment Synthesis of Scientific-Technical Information Relevant to Interpreting Article 2 of the U.N.

Framework Convention on Climate Change.

IPCC. 2007. “Summary for Policymakers.” In Climate Change 2007: The Physical Science Basis, edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.

Tignor, and H.L. Miller, 1–18. A Report of Working Group I of the IPCC. New York, New York, Cambridge University Press. Accessed September 2017. https://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf.

IPCC. 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

Edited by T.F. Stocker, D. Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A.

Nauels, Y. Xia, V. Bex, and P.M. Midgley. New York, New York: Cambridge University Press. http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf.

IPCC. 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II, and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf.

OPR (California Governor’s Office of Planning and Research). 2008. Technical Advisory – CEQA and Climate Change: Addressing Climate Change through California Environmental Quality Act (CEQA) Review. http://opr.ca.gov/docs/june08-ceqa.pdf.

PBL Netherlands Environmental Assessment Agency. 2018. Trends in Global CO2 and Total Greenhouse Gas Emissions, 2018 Report. Accessed May 2019. https://www.pbl.nl/sites/default/files/cms/publicaties/pbl-2018-trends-in-global-co2-andtotal-greenhouse-gas-emissons-2018-report_3125.pdf.

PG&E (Pacific Gas and Electric). 2020. 2020 Corporate Responsibility and Sustainability Report.

RSA. 2019. Hunter Subdivision Results of Preliminary Water Calculations.

Under 2 Coalition (Under 2). 2017. Under 2 Memorandum of Understanding. Updated September 2017. Accessed September 2017. http://under2mou.org/wp-content/ uploads/2015/05/Under2-Two-Pager-September-2017.pdf.

Agenda Item #6.2.

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3.8 HAZARDS AND HAZARDOUS MATERIALS

3.8.1 Introduction
This section provides an overview of the potential presence of hazards and hazardous materials and other public health hazards on and near the proposed Hunter Subdivision Project (Proposed Project) site and evaluates the potential impact to public health and safety and the environment that could result from the development and operation of the Proposed Project.

Comments received in response to the Notice of Preparation included concerns regarding flooding hazards, hazardous materials, fire hazards, and emergency access. A copy of the Notice of Preparation and comments received is included in Appendix A. Comments regarding the potential for flooding are addressed in Section 3.9, Hydrology and Water Quality, while hazardous materials released during a flood are discussed within this section. Hazardous materials, fire hazards, and emergency access are addressed in this section.

The evaluation is based on a review of Project site plans, City of St. Helena (City) planning documents, a review of historical land use documents and regulatory agency information, a Phase I Environmental Site Assessment (ESA) included in Appendix G, and a review of other available materials from state and federal agencies and databases. Other sources consulted are listed in Section 3.8.6, References.

3.8.2 Environmental Setting
This section describes the existing hazardous materials setting on and near the Project site, the existing regulatory framework for hazardous materials and hazardous waste and applicable worker health and safety requirements, and local policies related to public health and safety.

Existing Conditions
Hazardous materials, as defined by the California Health and Safety Code, may be present in the subsurface of any site as a result of past and present land uses. Exposure to hazardous materials could adversely affect the health of construction workers or the public during construction, as well as residents, or visitors to a site during operation if the hazardous materials are not contained, removed, or remediated.

Site Description and History
As stated in Chapter 2, Project Description, the Project site consists of approximately 17 acres with a small vineyard located in the southwestern and along the northwestern “panhandle” portion of the site. There are no structures or buildings located on the Project site. An existing groundwater well is located near the southeastern portion of the site. A stormwater detention Agenda Item #6.2.

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basin, as part of a previous City Flood Protection Project, is located to the north-northeast of the Project site. Historically the site has been used primarily for agricultural cultivation; likely vineyards and orchards, discussed in more detail below.

Historic Land Uses
As noted in Appendix G, past potential hazardous materials issues associated with historic land uses at and adjacent to the Project site were evaluated by reviewing historical aerial photographs from 1947, 1953, 1958, 1968, 1973, 1982, 1993, 2006, 2010, and 2014. Historic photographs indicate that the majority of the Project site was used for agricultural cultivation, likely vineyards and orchards. As shown in the photographs from 1947 through 1968, five ponds are visible outside of the Project site boundaries generally adjacent to the south and southeast.

It appears these ponds were removed after 1968 to construct the road and the adjacent Vineyard Valley Mobile Home Park. The Project site has remained as mostly agriculture with limited development.

The first development of the Project site appears to be prior to 1947 based on a review of aerial photographs, which shows an orchard in the northeast portion of the site while the remainder is visible as undeveloped grasslands. Holding ponds are visible along the southeastern border of the Project site and the surrounding areas consist of low-density residential development to the southeast and agriculture towards the north and west.

From 1953 through 1968, historic photos indicate no significant changes, other than the removal of the orchard. In 1973, vineyards appear on the southwest portion of the Project site and it appears the holding ponds were removed, and the initial stages of residential development are visible to the south and east.

Significant residential development surrounding the Project site first appears in 1982 as well as the presence of a small holding pond on the northeast portion of the Project site. The 1993 and 2006 photographs have little to no change to the site but indicate significant development of residences surrounding the site.

In the 2010 photograph, significant changes to the northern portion of the Project site are indicated. On the west, extending from the southern border, adjacent to the western boundary of the site, to the northern boundary of the site, a gravel access road appears. Grading on the Project site and to the north of the site, including the construction of a levee next to the riparian area north of the Project site is shown. In a more recent 2014 photograph, areas of fill has been covered with grasslands, the levee is completed, and an access maintenance road is shown along the northwestern boundary of the Project site extending from the southern end to north of the Project site.

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Sensitive Receptors
The Project site is bordered by residential development to the south and east. The closest schools to the Project site include the public Robert Louis Stevenson Middle School (0.67 miles west), the private St. Helena Montessori School (0.61 miles east), and the public St. Helena Elementary School (0.53 miles southwest). The Santa Rosa Memorial Hospital is located approximately 15 miles west of the Project site.

The Angwin-Parrett Field airport is the closest airport to the Project site and is located approximately 4.5 miles to the north-northeast.

Previous Site Investigations
In accordance with the American Society for Testing and Materials (ASTM) Standard E-1527, a Phase I ESA (Appendix G) was prepared by EBA Engineering on March 6, 2018.

Hazardous material issues at the Project site were evaluated by a thorough review of historical land use information, regulatory agency hazardous materials records and databases, and a site reconnaissance as part of the Phase I ESA.

The Project site was not identified in any regulatory agency files or databases as having recognized environmental concerns. The Phase I ESA determined that there was no indication of the historic use, generation, or disposal of hazardous materials and/or waste. There was no indication of the presence of any underground storage tanks on the Project site.

Agricultural chemicals have been recorded for use on the onsite vineyard from the Napa County Agricultural Commissioner’s Office (Appendix G). Agricultural chemicals recorded included herbicides, fungicides, and miticides. All chemicals used on the site were overseen by the Napa County Agricultural Commissioner’s Office in accordance with Title 3 of the California Code of Regulations. No agricultural chemicals were stored or mixed onsite. Historic aerial photographs of the site indicate an orchard was present dating from the 1940s; an era where it was common to use organochlorines and arsenic as pesticides; however, no record of use was found and no further subsurface investigation was identified (Appendix G).

A search of nearby areas in the Phase I ESA determined that no open or active sites were within 1,000 feet of the Project site. Based on a one-mile search radius (required by ASTM Standard 1527-13), three sites were identified as open/active for generation or handling of hazardous materials and/or wastes that are regulated for such use and disposal. The Phase 1 ESA notes 20 sites were found to be closed with regulatory oversight. Other open sites included seven sites that either were in the process of remediation, or on a list for being an active business such as an automotive shop. Due to their status, distance from the Project site, and Agenda Item #6.2.

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listing type (listed for generation and not for large spills), it was determined that these sites would not pose an environmental threat to the Proposed Project and therefore were not considered a recognized environmental concern. A complete list of sites can be found in Appendix G.

Additional Database Review
In addition to the Phase I ESA, the Department of Toxic Substances Control’s (DTSC) online database system, EnviroStor, was reviewed for recorded hazardous materials sites near the Project site. The Project site is not listed as a hazardous materials spill site, cleanup site, handler of hazardous materials, or facility which transports, stores, or produces hazardous materials (DTSC 2019).

Two sites are listed on the EnviroStor database, Klass Cleaners and Pacific Gas & Electric (PG&E), which are located approximately 2,440 feet and 2,700 feet south of the Project site, respectively. Klass Cleaners is an active voluntary cleanup site. The site has been a dry cleaning facility for the past 40+ years, which included the use, storage, and handling of hazardous materials including acetone, benzene, chloroform, tetrachloroethylene (PCE) and trichloroethylene (TCE) (EnviroStor 2019a). The business occupied the southern third of the building located at 1141 Main Street, approximately 2,440 feet south of the Project site. The site has been confirmed to have contaminated groundwater directly to the north (under a current gas station), and to the southeast of the building. Soil vapor contamination has been found directly under the building but has not been identified off the property. The complete lateral and vertical extent of contamination has not been determined (EnviroStor 2019a). The site became active through a Request for Agency Oversight Application on June 29, 2018. In August of 2018, PCE was detected through a site characterization report. Due to the site’s location, groundwater movement, contamination characteristics, and type of contamination, it is unlikely that this site would have an impact on the Proposed Project.

The PG&E site is a certified, operation and maintenance defined site as of July 18, 2017. This site was a manufactured gas plant which operated from 1883 until 1926. The site was purchased by PG&E in 1930 and was dismantled upon introduction of natural gas to the region in 1931. The site is located at 1301 Mitchell Drive, approximately 2,700 feet south of the Project site. During a standard site screening subsurface investigation at the site in 1987, it was discovered that polycyclic aromatic hydrocarbons, petroleum hydrocarbons, arsenic, and lead were detected. Remedial actions of the site were conducted in two phases. The first phase, excavation, was completed in 2007 and a dual phase soil vapor/ groundwater extraction system was installed. This system was operated for approximately 5 years. The second phase was completed in 2014 and included excavating and removing potentially contaminated soils up to 8 feet below the ground surface (EnviroStor 2019b). Groundwater was sampled and monitored Agenda Item #6.2.

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throughout remediation. A long-term operation and maintenance plan includes continuous groundwater monitoring and site inspections to ensure compliance with property use restrictions. In addition, land use restrictions between PG&E and DTSC dated March 17, 2017, include the prohibition of a residence, hospital, public or private schools, or a day care. Due to this site’s characteristics, location from the Project site, and groundwater sampling which has not peaked above remediation goals, this site is unlikely to pose a hazardous risk to the Proposed Project.

Wildland Fire Hazards
In accordance with California Public Resource Code Section 4201-4201 and Government Code Sections 51175–51189, the California Department of Forestry and Fire Protection (CAL FIRE) has mapped areas of significant fire hazards based on available fuels, terrain, weather patterns, and other relevant factors associated with wildland fire risks. These mapped zones, referred to as Fire Hazard Severity Zones, represent the risks associated with wildland fires. Under state law Government Code Section 511182, areas within very high fire hazard risk zones must comply with specific building and vegetation management requirements intended to reduce property damage and loss of life within these areas. There are two responsible designated areas, Local Responsibility Areas and State Responsibility Areas, which are in control of wildland fires within their respective areas. These are mapped through CAL FIRE.

On August 17, 2020, a series of overnight lighting strikes started fires that burned over 300,000 acres across five counties including Napa County. The LNU Lighting Complex fire was fully contained by early October. In late September 2020, the Glass Fire started and burned over 67,484 acres and destroyed over 1,800 structures in Napa County and Sonoma County. The fire was fully contained on October 20, 2020. The hills visible from the Project site experienced fire damage. The Project site is located within a Local Responsibility Area that is rated as a Non Very High fire Hazard Safety Zone (Non-VHFHSZ) (CalFire 2019).

3.8.3 Regulatory Setting
The U.S. Environmental Protection Agency (EPA) has granted most enforcement authority over federal hazardous materials regulations to the California Environmental Protection Agency (CalEPA) for issues within the state. In turn, the local agency, Napa County Department of Environmental Management has been granted responsibility for implementation and enforcement of many hazardous materials regulations within the City under the Certified Unified Program Agency (CUPA) Program.

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Federal Regulations
Resource Conservation and Recovery Act of 1976, as amended by the Hazardous and Solid Waste Amendments of 1984
Federal hazardous waste laws are generally promulgated under the Resource Conservation and Recovery Act (RCRA). The RCRA establishes a framework for national programs to achieve environmentally sound management of hazardous and non-hazardous wastes. The RCRA was designed to protect human health and the environment, reduce or eliminate the generation of hazardous waste, and conserve energy and natural resources. The RCRA also promotes resource recovery techniques. The Hazardous and Solid Waste Amendments of 1984 expanded the scope of the RCRA and increased the level of detail in many of its provisions. The Hazardous Waste Management subchapter of the RCRA deals with a variety of issues regarding the management of hazardous materials, including the export of hazardous waste, state programs, inspections of hazardous waste disposal facilities, enforcement, and the identification and listing of hazardous waste. In California, the EPA has authorized the DTSC to administer the RCRA program, pursuant to the State’s Hazardous Waste Control Law.

Comprehensive Environmental Response, Compensation, and Liability Act and the Superfund Amendments and Reauthorization Act of 1986
Congress enacted the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, on December 11, 1980. CERCLA established prohibitions and requirements concerning closed and abandoned hazardous waste sites, provided for liability of persons responsible for releases of hazardous waste at these sites, and established a trust fund to provide for cleanup when no responsible party could be identified.

The Superfund Amendments and Reauthorization Act amended CERCLA on October 17, 1986.

The Superfund Amendments and Reauthorization Act stresses the importance of permanent remedies and innovative treatment technologies in cleaning up hazardous waste sites, requires Superfund actions to consider the standards and requirements found in other state and federal environmental laws and regulations, provided new enforcement authorities and settlement tools, increased state involvement in every phase of the Superfund program, increased the focus on human health problems posed by hazardous waste sites, encouraged greater citizen participation in making decisions on how sites should be cleaned up, and increased the size of the trust fund.

Hazardous Materials Transportation Act
The U.S. Department of Transportation regulates hazardous materials transportation under Code of Federal Regulations (CFR) Title 49. State agencies with primary responsibility for enforcing federal and state regulations and responding to hazardous materials transportation Agenda Item #6.2.

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emergencies are the California Highway Patrol and the California Department of Transportation.

These agencies also govern permitting for hazardous materials transportation.

EPA Regional Screening Levels
Regional Screening Levels are tools for evaluating and cleaning up contaminated sites.

Regional Screening Levels for the Superfund programs provide comparison values for residential and commercial/industrial exposures to soil, air, and tap water. These values are risk-based concentrations, derived from standardized equations combining exposure information assumptions with EPA toxicity data. They are considered to be protective for humans (including sensitive groups) over a lifetime.

State Regulations
Routine hazardous materials management in California is administered under the CUPA program.

The CUPA program was established under the 1993 California Senate Bill 1082 to reduce the cost and improve the efficiency of enforcement of hazardous materials laws and regulations.

California Government Code Section 65962.5(a), Cortese List The Hazardous Waste and Substance Sites (Cortese) List is a planning document used by state and local agencies and developers to comply with California Environmental Quality Act (CEQA) requirements to provide information about the location of hazardous materials release sites.

California Government Code Section 65962.5 requires the CalEPA to develop, at least annually, an updated Cortese List. The DTSC is responsible for a portion of the information contained in the Cortese List. Other state and local government agencies are required to provide additional hazardous material release information for the Cortese List. The Project site is not listed on the Cortese List database.

Title 22 of the California Code of Regulations and Hazardous Waste Control Law, Chapter 6.5 The DTSC regulates the generation, transportation, treatment, storage, and disposal of hazardous waste under the RCRA and the California Hazardous Waste Control Law. Both laws impose “cradle-to-grave” regulatory systems for handling hazardous waste in a manner that protects human health and the environment. CalEPA has delegated some of its authority under the Hazardous Waste Control Law to county health departments and other Certified Unified Program Agencies, including the Napa County Environmental Health Division. In California, the EPA has authorized the DTSC to administer the RCRA program, pursuant to the state’s Hazardous Waste Control Law.

Agenda Item #6.2.

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California Human Health Screening Levels
California Human Health Screening Levels (CHHSLs or “Chisels”) are concentrations of 54 hazardous chemicals in soil or soil gas that CalEPA considers to be below thresholds of concern for risks to human health. The CHHSLs were developed by the Office of Environmental Health Hazard Assessment on behalf of CalEPA. The CHHSLs were developed using standard exposure assumptions and chemical toxicity values published by the EPA and CalEPA. The CHHSLs can be used to screen sites for potential human health concerns where releases of hazardous chemicals to soils have occurred. Under most circumstances, the presence of a chemical in soil, soil gas, or indoor air at concentrations below the corresponding CHHSL can be assumed to not pose a significant health risk to people who may live or work at the site.

There are separate CHHSLs for residential and commercial/industrial sites.

California Emergency Services Act
The California Emergency Services Act was adopted to establish the state’s roles and responsibilities during human-caused or natural emergencies that result in conditions of disaster and/or extreme peril to life, property, or resources of the state. This act is intended to protect health and safety by preserving the lives and property of the people of the state.

California Natural Disaster Assistance Act
The California Natural Disaster Assistance Act provides financial aid to local agencies to assist in the permanent restoration of public real property, other than facilities used solely for recreational purposes, when such real property has been damaged or destroyed by a natural disaster. The California Natural Disaster Assistance Act is activated after the following occurs: a local declaration of emergency and the California Emergency Management Agency gives concurrence with the local declaration, or the governor issues a proclamation of a state emergency. Once the act is activated, local government is eligible for certain types of assistance, depending on the specific declaration or proclamation issued.

Title 14 Division 1.5 of the California Code of Regulations Title 14 of the California Code of Regulations, Division 1.5, establishes the regulations for CAL FIRE and is applicable in all State Responsibility Areas—areas where CAL FIRE is responsible for wildfire protection. Most of the unincorporated area of Napa County is a State Responsibility Area, and any development in a State Responsibility Area must comply with these regulations.

The City is not within the unincorporated area of Napa County and is not within a State Responsibility Area. Among other things, Title 14, Section 1270 et seq. establishes minimum standards for emergency access, fuel modification, setback to property lines, signage, and water supply.

Agenda Item #6.2.

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Uniform Fire Code
The Uniform Fire Code contains regulations relating to construction, maintenance, and use of buildings. Topics addressed in the code include fire department access, fire hydrants, automatic storage and use, provisions intended to protect and assist fire responders, industrial processes, and many other general and specialized fire-safety requirements for new and existing buildings and the surrounding premises. The code contains specialized technical regulations related to fire and life safety.

Building, Fire and Residential Code
The State Fire Marshal’s Building, Fire and Residential Code went into effect on January 1, 2011. This code incorporated the requirement of residential fire sprinklers in all new one-and two-family dwellings and townhouse construction statewide into the 2010 California Building Standards Codes. Fire sprinkler systems are also required in office buildings and multi-family dwellings (i.e. apartments).

California Health and Safety Code
State fire regulations are set forth in Sections 13000 et seq. of the California Health and Safety Code, include regulations for building standards (as also set forth in the California Building Code), and fire protection and notification systems, fire protection devices such as extinguishers and smoke alarms, high-rise building and childcare facility standards, and fire suppression training.

Local Regulations
Napa County Agricultural Commissioner’s Office
The Napa County Agricultural Commissioner and staff are responsible for the implementation of federal, state, and local regulatory programs within Napa County. Specifically, these programs are designated to protect people and the environment and promote agriculture within Napa County. Agriculture in and around St. Helena uses a variety of hazardous materials, including fuels and maintenance fluids for farm equipment, fertilizers, and pesticides (including herbicides, fungicides, and insecticides).

Pesticides are regulated under the federal Insecticide, Fungicides and Rodenticide Act by the EPA. This includes labeling and registration of pesticides as to how they may be used.

The EPA delegates pesticide enforcement activities in California to the California Department of Pesticide Regulation, under Title 3 of the California Code of Regulations and the California Food and Agriculture Code. The California Department of Pesticide Agenda Item #6.2.

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Regulation register pesticides for use in California, and licenses pesticide applicators and pilots, advisors, dealers, brokers, and businesses.

As stated above, the City of St. Helena’s hazardous materials programs are administered and enforced by the Napa County Department of Environmental Management under the CUPA program.

Napa County Operational Area Hazard Management Plan
The City participated in the Napa County Operational Area Hazard Management Plan, which was adopted in 2013 and satisfies the requirements of the Disaster Mitigation Act of 2000. The plan includes a risk assessment that resulted in the profiling of hazards that pose risk to Napa County (including the incorporated cities), assessment of Napa County’s vulnerability to those hazards, and examined the capabilities in place to mitigate them. Vulnerabilities identified, profiled, and analyzed in this plan include flooding, earthquakes, and wildland/urban interface fires. The plan also identifies goals for reducing risks from hazards. Objectives of the plan are to protect life and property; ensure emergency services; increase public awareness and understanding of hazard mitigation; protect critical facilities properties, infrastructure and other community assets from the impacts of hazards; and continue to strengthen communication and build on the collaborative success already achieved. In addition to county-wide risk assessment, the plan includes city-specific risk assessments.

Napa County Emergency Operations Plans
The Napa County’s Concept of Operations Base Plans include the Napa County’s Public Health Division Health and Human Services Agency Concept of Operations Base Plan; Crisis Emergency Risk Communication Plan, Strategic National Stockpile Plan, Countermeasure Distribution Plan, Outbreak/Epidemiologic Response Plan; Medical Surge Plan; Mass Care and Shelter Plan; Campus Response Plan; Local Assistance Center Plan; Excessive Heat emergencies Response Plan; Fatality Management Plan; and a Healthcare Evacuation Plan (Napa County 2019).

The Base Plans establish the Napa County Public Health Division Health and Human Services Agency’s emergency organization, assigns task, specifies policies and general procedures, and provides for coordination of planning efforts using the Standardized Emergency Management System (SEMS) and the National Incident Management System (NIMS). The primary threats to Napa County include earthquakes, floods, landslides, fires, disease outbreaks, hazardous materials releases, transportation accidents, and national security incidents (Napa County 2019).

Agenda Item #6.2.

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The Base Plans include a system of operations with scenarios and procedures in the event of an emergency. Each plan listed above provides detailed training guidance for staff and volunteers- including clear and concise roles and responsibilities within each department and organization; risk communication media and outreach goals, methods, and policies; public outreach, and public health division spokesperson to deliver approved information to the public during a crisis.

Napa County Draft 2019 Multi-Jurisdictional Hazard Mitigation Plan Update Napa County, along with other jurisdictions, is planning to develop, but has not yet adopted, an update to the Napa County Operational Area Hazard Mitigation Plan of 2013.

Hazard mitigation is the use of long-term actions to reduce the loss of life, personal injury, and property damage that can result from a disaster. Planning efforts could include capital projects and other pragmatic activities that can mitigate the impacts of hazards. The draft 2019 MultiJurisdictional Hazard Mitigation Plan update would cover each of the major natural hazards that pose risks to Napa County infrastructure and residents.

The 2019 draft Multi-Jurisdictional Hazard Mitigation Plan update would include, at a minimum, the jurisdictions listed below. It is understood that Napa County also encompasses areas of land controlled by federal and state land management agencies including the California Department of Forest and Fire Protection, Bureau of Land Management, and Bureau of Reclamation. The following jurisdictions would meet Federal Emergency Management Agency guidelines and requirements as a formal participating agency, City of American Canyon, City of Calistoga, City of St. Helena, Town of Yountville, Napa County Flood Control and Water Conservation District, Napa County Office of Education, and Napa Valley College (Dynamic Planning and Science 2016).

The 2019 Multi-Jurisdictional Hazard Mitigation Plan update would include a comprehensive plan for flood damage reduction, additional mapping of properties which sustain repetitive losses due to flooding, and detailed inundation mapping technology. The plan would also include updated preparedness controls for wildfire mitigation, and earthquake mitigation.

City of St. Helena 1993 General Plan
The existing 1993 General Plan does not contain policies related to hazardous materials.

However, it does contain the following implementing policies regarding emergency response included in the Public Health and Safety Element:

Policy 8.5.2: Protect St. Helena residents from health and safety impacts related to the use, storage, manufacture or transport of hazardous materials.

Agenda Item #6.2.

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Policy 8.5.6: Require all new development to meet the minimum fire flow rates specified by the City’s Fire Code.

Policy 8.5.7: Ensure that all streets and roads are adequate in terms of width, turning radius, and grade to facilitate access by City firefighting apparatus, and to provide alternative emergency ingress and egress.

Policy 8.5.9: Review all new development proposals for their potential to introduce the production, use, storage, and/or transport of hazardous materials, and require reasonable controls on such hazardous materials
Policy 8.7.2: Maintain and periodically update the City’s Emergency Response Plan.

Policy 8.7.3: Conduct periodic emergency response exercises to test the effectiveness of City emergency response procedures.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The 2019 General Plan contains the following policies regarding hazardous materials, emergency response and best practices included in the Public Health and Safety Element:

Policy PS4.3: Protect St. Helena residents from health and safety impacts related to the use, storage, manufacture, and transport of hazardous materials.

Policy PS4.4: Discourage new uses that rely extensively on the use of hazardous materials.

Policy PS4.5: Facilitate communication and education about fire safety, non-point source pollution, household hazardous waste disposal, and recycling opportunities.

Policy PS4.6: Ensure that all streets and roads are adequate in terms of width, turning radius, and grade in order to facilitate access by City firefighting apparatus, and to provide alternative emergency routes of ingress and egress.

Policy PS4.D: Require all new development to meet the minimum fire flow rates specified by the City’s Fire Code.

St. Helena Municipal Code
Chapter 15.36 of the City’s Municipal Code adopted the 2010 California Fire Code for all buildings and construction within the city. Chapter 2.64 aims to provide for the preparation and carrying out of plans for the protection of persons and property within the city in the event of an emergency; the direction of the emergency organization; and the coordination of the emergency Agenda Item #6.2.

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functions with all other public agencies, corporations, organizations, and affected private persons. This chapter also establishes responsibilities for carrying out the City’s emergency plan, which the City has not yet adopted.

The St. Helena emergency council is responsible for the development of the City’s emergency plan, which shall provide for the effective mobilization of all City resources, both public and private. The council is to meet any condition constituting a local emergency, state of emergency, or state of war emergency; and provides for the organization, powers and duties, services, and staff of the emergency organization. The plan takes effect upon adoption by resolution of the City Council.

3.8.4 Impacts
Methods of Analysis
The analysis of the potential public safety and hazardous materials impacts is based on information from the Phase I ESA prepared for the Proposed Project (Appendix G), a review of City planning documents, historical land use documents, regulatory agency literature/database review, and other existing documentation used to establish existing conditions and to identify potential environmental effects based on the standards of significance presented in this section.

In determining the level of significance, the analysis assumes that the Proposed Project would comply with all applicable state and local ordinances and regulations (summarized above).

As noted above, potential hazards and associated impacts related to hazards associated with flooding or a levee break and emergency procedures in the event of a flood are discussed in Section 3.9, Hydrology and Water Quality.

Thresholds of Significance
Consistent with Appendix G of the CEQA Guidelines, a significant impact would occur if development of the Proposed Project would do any of the following:
• Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials.
• 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.
• Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school.

Agenda Item #6.2.

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• Be located on a site which is included on a list of hazardous materials sites complied pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment.
• For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area. • Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan.
• Expose people or structures, either directly or indirectly, to a significant risk of loss, injury, or death involving wildland fires.

Threshold Criteria not Applicable to the Proposed Project Due to the characteristics and location of the Proposed Project, certain criteria thresholds listed above are not applicable and therefore would not be considered potential impacts. These criteria are addressed below and not discussed further in this Environmental Impact Report (EIR).

Nearby Schools
The Project site is not located within one-quarter mile of an existing or proposed school. The closest schools to the Project site include Robert Louis Stevenson Middle School (0.67 miles west), St. Helena Montessori School (0.61 miles east), and St. Helena Elementary School (0.53 miles southwest). Because no existing or proposed school is within one-quarter mile of the Project site, and Proposed Project residences would not be expected to use or handle acutely hazardous materials, substances, or waste there would be no impacts and this issue (third significance threshold listed above) is not further evaluated.

Previously Listed Hazardous Site
As stated above, a Phase I ESA (Appendix G) was prepared for the Project site and included a search of databases pursuant to Government Code Section 65962.5. The Phase I ESA also included historic aerial photographs of the Project site to determine prior, un-documented land uses and the surrounding properties. The Proposed Project is not located on a site which is included on a list of hazardous materials and would therefore not create a significant hazard to the public or the environment. There would be no impact and this issue (fourth significance threshold listed above) is not further discussed.

Agenda Item #6.2.

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Airports
The Project site is not located within an airport land use plan or within 2 miles of an airport. The closest airport to the Project site is the Angwin-Parrett Field airport located approximately 4.5 miles north-northeast of the site. Proposed Project residents would not be impacted by excessive noise from an airport and the Proposed Project does not include towers or other tall obstructions that could interfere with air travel. There would be no impact and this issue (fifth significance threshold listed above) is not further discussed.

Impacts and Mitigation Measures

3.8-1: Would the Proposed Project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? This impact would be less than significant.

Construction
During construction activities, hazardous materials, such as petroleum (fuels, motor oil, lubricants), would be used for equipment. In general, small amounts of these materials would be on site at any one time. No acutely hazardous materials would be used during construction of the Proposed Project. In addition, materials handled would not pose a significant risk to off-site residents or construction workers because they would be used and stored in accordance with existing laws and regulations. Development of the Proposed Project would be subject to existing regulatory requirements for hazardous materials, including requirements under the National Pollutant Discharge Elimination System permit through the development and implementation of a Stormwater Pollution Prevention Plan (SWPPP), discussed in Section 3.9, Hydrology and Water Quality. The SWPPP would require implementation of control measures for hazardous material storage, soil stockpiles, inspections, maintenance, training of employees, and containment of releases to prevent contaminated runoff into nearby stormwater collection systems or waterways. Included within the SWPPP, best management practices would be required to contain hazardous materials and minimize the contact of hazardous materials with stormwater. As part of the SWPPP, spill prevention measures would be described for each chemical type and secondary containment of those chemicals would be used to ensure that spills can be managed and limited to the containment areas. Although not anticipated, if quantities of fuel or oil greater than or equal to 1,320 gallons are stored on the Project site during construction, then a Spill Prevention Control and Countermeasure Plan must be prepared in accordance with 40 CFR 112.

With the implementation of the SWPPP, and proper handling methods for each chemical type, impacts to the public or environment through the routing transport, use, and disposal of hazardous materials would be less than significant.

Agenda Item #6.2.

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Operation
During Proposed Project operation, residents would be expected to use and store typical household hazards such as house paint, cleaning products, herbicides, and pesticides. The amounts of hazardous materials that residents store or use is negligible and not considered sufficient to create a significant safety hazard to the public, or otherwise pose a significant risk to human health or the environment. Napa County handles the disposal of household hazardous waste at their collection facility located at 889A Devlin Road in south Napa; approximately 30 miles south of the Project site.

Implementation of local hazardous materials programs and requirements as stated above, in addition to compliance with state and federal laws and regulations, would ensure that the Proposed Project would not create a significant hazard to the environment through routine transport, storage, use, and disposal of hazardous materials. Based on information provided above, this potential impact would be less than significant.

Mitigation Measures
None required.

3.8-2: Would the Proposed 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? This impact would be potentially significant.

Construction
During construction activities, hazardous materials such as solvents, petroleum (lubricants and fuels), and other typical construction equipment would be used. Amounts would be negligible and a hazardous spill plan would be implemented as part of the construction contractor’s SWPPP (discussed under Impact 3.8-1, above). Best management practices would also be implemented as part of the SWPPP in order to reduce the likelihood of hazardous materials spills. Secondary containment containers would be used as part of storing fuels or hazardous materials on the Project site. In the event of a spill of hazardous materials, most, if not all, chemicals would be limited to the Project site or immediate vicinity as the amounts stored, used, or transported on the site would be minimal and unlikely to cause a significant impact on the public and environment. This impact is less than significant.

Due to the historic use of a portion of the site for agricultural uses, specifically an orchard in the late 1940s, there is a potential for contaminated soils to be encountered during construction activities. Potentially contaminated soils would include the past application of unregulated Agenda Item #6.2.

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pesticides. Prior agricultural activities may have used organochlorine pesticides (OCPs), such as DDT, toxaphene, dieldrin, etc., as well as arsenic in the form of arsenical herbicides, which has a history of use on many agricultural properties. Organochlorine pesticides were first introduced into California agriculture in 1944 and reached peak usage in the 1960s. In 1974, the use of the DDT was banned for agricultural purposes, and the elimination of remaining OCPs in California agriculture quickly followed. OCPs are biopersistent and bioaccumulate in the environment, whereas other types of pesticides have a short half-life (i.e., they degrade fairly quickly with time). Today, pesticides are required to demonstrate a lack of persistence in the environment considerably beyond their intended period of use in order to obtain EPA approval.

Furthermore, when pesticides are used properly and in accordance with label specifications, potential impacts on the surrounding environment and receiving waters (surface water and groundwater) are minimized. Therefore, the primary concern from a human health perspective is the potential for residual levels of OCPs and/or arsenical herbicides which were in common use in the mid-1900s.

The Phase I ESA prepared for the Project site (Appendix G) concluded that the site is not subject to any recognized environmental concerns. Under ASTM Standard E1527-13, a recognized environmental concern means the presence or likely presence of hazardous substances or petroleum products in, on, or at a property, due to any release to the environment, under any conditions indicative of a release to the environment, or under conditions that pose a material threat of a future release to the environment. The conclusion is based on an extensive review of regulatory agency records pertaining to the storage, use and/or potential release of hazardous materials, including pesticide use records from the Napa County Agricultural Commissioner’s Office; as well as owner/operator interviews, site reconnaissance, and review of historical aerials and topographic maps. Regarding the potential for past use of OCPs, such as DDT, toxaphene, dieldrin, etc., the Phase I ESA concluded that it is unlikely that any significant concentrations would be present onsite, based on the fact that no agricultural chemicals have been stored or mixed onsite and because if such chemicals were historically used, they would have likely degraded to the point where their concentrations no longer pose a threat to human health or the environment. While the Phase I ESA concludes that it is unlikely that residual levels of pesticides would be present in significant concentrations, the absence of contaminants of concern such as OCPs and arsenic has not been confirmed through on-site soils testing. This is an issue of concern that was brought up in comments in response to Notice of Preparation. The impact to human health and the environmental from residual concentrations of OCPs and/or arsenic is considered a potentially significant impact because the Proposed Project includes sensitive receptors (residents), and because the finding of the Phase I ESA has not been confirmed through on-site soils testing.

In the event of a flood during construction, hazardous materials associated with construction activities may be released into flood waters and expose people or the environment to hazardous Agenda Item #6.2.

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conditions. However, as further discussed in Section 3.9, the Napa River levee has been designed to withstand a 200-year storm event. Due to the extreme volume of flood water associated with a 200-year storm event, the maximum amount of hazardous materials associated with the proposed construction activities that could be released would be negligible as compared to the amount of hazardous materials that would be transported under existing conditions. This is a considered a less-than-significant impact.

Operation
Future residents at the Project site would be bordered by agricultural uses to the north/northwest, existing residences to the south and east, and undeveloped land and a flood control levee along the Napa River to the north/northeast. Residences, as stated above, typically use small amounts of household hazardous wastes. The use of these types of household products would not be of a large enough quantity to result in a significant hazard to the public or the environment through the event of an accidental release.

As during construction, in the event of a flood, household hazardous materials from Proposed Project operation may be released into flood waters and expose people or the environment to hazardous materials. However, as further discussed in Section 3.9 of this EIR, the Project site is protected by a levee which was built to withstand a 200-year flooding event. Due to the extreme volume of flood water associated with a 200-year storm event, the maximum amount of hazardous materials associated with the proposed construction activities that could be released would be negligible as compared to the amount of hazardous materials that would be transported under existing conditions. This is considered a less-than-significant impact.

Mitigation Measures
Implementation of Mitigation Measure HAZ-1 would ensure that if soils located within the Project site contain pesticides that exceed CHHSLs for residential development and occupancy, such soils would be removed and/or remediated prior to any site disturbance or occupancy. With implementation of Mitigation Measure HAZ-1, a preliminary soil screening survey would ensure that soils on the Project site would comply with CHHHLs for residential development and occupancy ensuring the impact is mitigated to less than significant.

HAZ-1: As a condition of approval for construction and grading permits for the Project site, the Project applicant shall ensure the following subsurface soils testing and follow-up analysis shall be performed prior to obtaining a grading permit:
• A soils testing work plan shall be developed in accordance with DTSC’s Interim Guidance for Sampling Agricultural Properties (DTSC 2008) by an appropriately licensed individual (i.e., professional geologist, environmental Agenda Item #6.2.

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engineer, or similar qualification) for the portions of the Project site historically used for agriculture. Special consideration shall be given to targeting site soils that are representative of historic agricultural use, and to avoid sampling recent fill material placed during levee construction. Prior to carrying out soils testing, the work plan shall be submitted to the Napa County Division of Environmental Health (as the Certified Unified Program Agency for all cities and areas of Napa County) and the City of St. Helena for review and approval.
• The number of soil samples, sampling methods, compounds tested, background samples (if applicable), and laboratory analyses shall be completed in accordance with DTSC’s Interim Guidance. Should analytical results exceed naturally occurring concentrations or applicable CHHSLs, the health risks of such a condition shall be evaluated in human health risk assessment as described in DTSC standards and guidance (e.g., preliminary endangerment assessment guidance manual).
• The risk assessment shall describe measures that must be implemented to ensure potential health risks to construction workers, site residents, and the general public as a result of hazardous materials are reduced to a cumulative risk of less than one in one million for carcinogens and a cumulative hazard index of 1 for non-carcinogens, or as required by the Napa County Division of Environmental Health acting as the Certified Unified Program Agency and/or DTSC oversight.
• In the event human health risk assessment shows elevated chemical concentrations pose a risk to human health or the environment, the risks shall be eliminated or substantially reduced by removal (e.g., excavation of soils and off-site disposal) or remediation of contaminated soils, and/or implementation of institutional controls and engineering controls (IC/EC).

IC/EC may include use of a construction risk management plan, use of hardscape to cap problem areas, importation of clean soil in landscaped area to eliminate exposure pathways, and/or deed restrictions. If IC/EC are implemented, an Operations and Maintenance Program shall be prepared and implemented to ensure that the measures adopted are maintained throughout the life of the project.

The soil testing report, and if applicable, the human health risk assessment and Operations and Maintenance Program, shall be subject to review and approval by the City of St. Helena Department of Public Works, the Napa County Division of Environmental Health and/or other regulatory oversight agencies.

Agenda Item #6.2.

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3.8-3: Would the Proposed Project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? This impact would be less than significant.

Construction
Construction activities could physically interfere with an adopted emergency response or evacuation plan if it did not adhere to the requirements of such plans. The City currently does not have an adopted emergency evacuation plan and relies on the Napa County Emergency Operations Plans and the City’s fire department to review site plans to ensure adequate access is provided in the event of an emergency. During construction activities in the event of a fire, hazardous spill, or other emergency access for emergency personnel and equipment as well as access for construction workers to evacuate the site would be available. The construction contractor would also implement the SWPPP, as discussed under Impact 3.8-1. The SWPPP would include an Integrated Contingency Plan and an evacuation plan for construction workers in the event of an emergency. The evacuation plan would be used in case of a fire, potential life threatening hazardous materials release, or any other emergency situation that has the potential to harm human life and safety. The evacuation plan would be prepared in accordance and oversight of City staff. Compliance with the SWPPP and the Integrated Contingency Plan would ensure impacts are less than significant.

Operation
The Proposed Project’s tentative map is designed with three points of access; the extension of Star Avenue and Adams Street and an emergency vehicle access (see Figure 2-3 in Chapter 2, Project Description) to facilitate the ingress and egress of emergency response vehicles, including the City and County Fire Department’s apparatus and Proposed Project residents. The City’s Fire Department would review the site plans to determine if any additional road widening or access is recommended. The emergency vehicle access would be designed with bollards or a fence that would be kept locked. In the event of an emergency requiring evacuation, police or fire personnel/vehicles would have access to remove the bollards/unlock the gate through a locked box (e.g., knox box). Proposed Project operation would not interfere with the preparation of the City’s emergency response plan or Napa County’s Emergency Operations plan as it would be designed to comply with the California Building Code, as well as the 1993 General Plan and 2019 General Plan’s community design standards; all of which include emergency response access features. The Community Design Element of the 1993 General Plan and 2019 General Plan include requirements for residential design to conform with the patterns and densities of neighboring areas, as well as accessibility for residents. The General Plans also include fire and hazardous materials guiding policies which require new development to meet the minimum fire flow rates specified by the City’s Fire Code (Policy 8.5.6 in the 1993 General Agenda Item #6.2.

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Plan and Policy PS4.D in the 2019 General Plan), as well as ensuring all streets and roads are adequate in terms of width, turning radius, and grade to facilitate access by City firefighting apparatus, and to provide alternative emergency ingress and egress (Policy 8.5.7 in the 1993 General Plan and Policy PS4.D in the 2019 General Plan).

Compliance with City policies and regulations would ensure the Proposed Project would not impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan; therefore, the impact would be less than significant.

Mitigation Measures
None required.

3.8-4: Would the Proposed Project expose people or structures, either directly or indirectly, to a significant risk of loss, injury, or death involving wildland fires? This impact would be less than significant.

Construction
The Project site is bordered by residential development to the south and east. Irrigated agricultural land and undeveloped lands surround the Project site to the southwest, west, northwest, and directly north, with the exception of the Napa River which is north/northeast of the Project site. Across the Napa River, farther to the north, are additional irrigated agricultural lands. The Project site and the surrounding land uses are located within an area mapped as “Non-VHFHSZ” under the Local Responsibility Area map by CAL FIRE (CalFire 2019).

Construction activities have the potential to cause sparks which may cause a fire. As discussed under Impact 3.8-2, best management practices included within the recommended SWPPP would include precautions to temporarily remove vegetation in areas where construction equipment or vehicles would access, as well as have a water supply onsite for fire protection.

As stated in Section 3.3, Air Quality, the Bay Area Air Quality Management District’s Regulation 6, Rule 6 addresses the prohibition of fugitive road dust emissions associated with trucks tracking mud onto local roads “trackout.” To comply with the Bay Area Air Quality Management District’s regulations for fugitive dust and trackout, the Project site would be regularly watered for dust suppression during construction activities, which would serve a dual purpose in also reducing the risk for fires to occur. Impacts related to wildland fires during construction activities would be considered less than significant.

Agenda Item #6.2.

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Operation
The Proposed Project’s residences would be built to the California Building Code requirements for fire protection in place at the time. During Proposed Project operation sparks from vehicles is lowered because vehicles accessing the site would be on paved roads and adjacent landscape strips or yards would be set back from the road via a 4-foot-wide sidewalk.

Also, the landscape strip and yards would be regularly irrigated during the dry summer and fall months so it is unlikely there would be access to dry grass where many wildfires start.

Likewise, landscape equipment including lawnmowers and other common handheld power tools would be used on irrigated lawns and unlikely to be used on any dry grassy areas where sparks could initiate a wildfire.

As stated previously, the Proposed Project’s tentative map is designed with an emergency vehicle access to facilitate the ingress and egress of emergency response vehicles, including the City and Napa County Fire Department’s apparatus. The City’s Fire Department would ensure the final site plans provide adequate emergency evacuation and would be consistent with the City’s emergency response plan, when it is prepared. In the event of a fire, there would be sufficient access for emergency vehicles to reach the Project site, as well as emergency evacuation access for residents. The Napa County Emergency Operations Plan does not include a vehicle evacuation plan, but in the event of a wildfire, City fire and police personnel would coordinate with Napa County to identify evacuation routes and set up temporary shelters for anyone asked to evacuate. Because the Proposed Project would not conflict with the Napa County Emergency Operations Plan and provides adequate access in the event of a wildfire; the impact is less than significant.

Mitigation Measures
None required.

3.8.5 Cumulative Impacts
The cumulative context for the analysis of potential hazardous materials impacts (including hazardous materials usage during construction, exposure to potentially contaminated soils) is generally site-specific, rather than cumulative in nature. Compliance with all applicable federal, state, and local regulations related to hazards and hazardous materials on a project-by-project basis would be required for all projects within the City. Therefore, these issues are not addressed in the cumulative impact analysis.

Hazardous materials incidents or accidents would also typically be site-specific and would involve accidental spills or inadvertent releases. The effects of such incidents, then, would not be additive to effects from other, similar incidents occurring elsewhere. Associated health and Agenda Item #6.2.

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safety risks generally would be limited to those individuals using the materials or to persons in the immediate vicinity of the materials. Therefore, these issues are not addressed in the cumulative impact analysis.

The cumulative context for the use, handling, storage, and transport of hazardous materials is buildout of the City. This geographic scope is selected because (1) cumulative hazardous effects generally require proximity, and (2) City personnel are the first responders to hazardous accidents within the vicinity of the Project site.

3.8-5: Would the Proposed Project contribute to a cumulative increase in the potential exposure of people to sites where soil contamination could be present from past or current uses, or to hazards associated with the use and transport of hazardous materials? The Project’s contribution would be less than considerable.

The Proposed Project, in conjunction with other past, present, and reasonably foreseeable future development within the City, could entail development of a site where past uses could have resulted in soil contamination, the potential exists for release of hazardous substances during construction. For individuals not involved in construction activities, the greatest potential source of exposure to contaminants would be airborne emissions, primarily through dust either from soil remediation activities or from soil-disturbing activities during construction where previously unidentified contamination may exist. (Other potential pathways, such as direct contact with contaminated soils or groundwater would not pose as great a risk to the public because such exposure scenarios are site-specific and would typically be confined to the construction zones.)
The City’s 1993 General Plan determined that the routine use and transport of hazardous materials, hazardous materials use near schools, emergency response, and wildfire hazards would be a potentially significant impact due to development on former agricultural, commercial, or industrial properties and potential exposure to contaminants from historic hazardous materials use and release (City of St. Helena 2010). However, the City’s 2019 General Plan Draft EIR (City of St. Helena 2018) was reviewed and it concluded that the routine use and transport of hazardous materials, hazardous materials use near schools, emergency response, and wildfire hazards were less than significant based on the implementation of existing and applicable laws and regulations. Potentially significant impacts included the development on former agricultural, commercial, or industrial properties which may expose construction workers and future occupants or neighboring residents from historical hazardous materials and release; and new developments could affect groundwater or surface water resources through the use and disposal of hazardous materials. These potentially significant impacts identified within the General Plans would be less than significant through compliance with General Plan policies.

Agenda Item #6.2.

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The Proposed Project, in combination with other development projects in the City, would not result in any cumulative significant effects. This assumption is based on the results of the Phase I ESA that stated impacts related to past use of pesticides on the Project site associated with former agricultural activities are minimal and do not necessitate any corrective action. However, although unlikely to be found in high concentrations, in order to further quantify any potential pesticide amounts, an on-site soil testing would be required. Therefore, it is extremely unlikely that any one individual outside of any particular project site construction zone would be exposed to maximum levels of construction-generated contaminated air emissions (if any) for the entire development period, even if controls were not in place.

Therefore, compliance with applicable hazardous materials management laws and regulations adopted at the federal, state, and local level would ensure the Proposed Project’s contribution to cumulative impacts related to soil contamination related to Proposed Project construction effects would not be considerable and the Proposed Project would not contribute to a cumulative impact resulting in a less-than-significant impact.

Mitigation Measures
None required.

3.8.6 References
CalFire 2019. Local Responsibility Area. Wildland Hazard & Building Codes, Napa County FHSZ Maps. http://www.fire.ca.gov/fire_prevention/fhsz_maps_napa.

California Department of Toxic Substances Control (DTSC) 2019. DTSC EnviroStor Online Database Interactive System.

City of St. Helena. 1993. City of St. Helena 1993 General Plan. September 18, 1993.

City of St. Helena. 2018. City of St. Helena General Plan Update 2040 Draft Environmental Impact Report SCH# 2010042001. May 2018.

City of St. Helena. 2019. City of St. Helena General Plan Update 2040. May 2019.

EBA Engineering, 2018. Phase I Environmental Site Assessment APN 009-030-057 Saint Helena, California. Prepared on March 6, 2019. EBA Project No. 18-2550. Prepared for Ms. Ben Van Zutphen.

EnviroStor 2019a. Online report summary for DTSC site KLASS CLEANERS (60002699). https://www.envirostor.dtsc.ca.gov/public/profile_report?global_id=60002699.

Agenda Item #6.2.

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EnviroStor 2019b. Online report summary for DTSC site PG&E ST HELENA (28490002). https://www.envirostor.dtsc.ca.gov/public/profile_report?global_id=28490002.

DTSC (California Department of Toxics Substances Control). 2008. Interim Guidance for Sampling Agricultural Properties (Third Revision). California Environmental Protection Agency. https://www.dtsc.ca.gov/Schools/upload/Ag-Guidance-Rev-3-August-7-2008-

2.pdf. August 7, 2008.

Dynamic Planning and Science 2019. Napa County Multi Jurisdictional Hazard Mitigation Plan 2019 Update. Accessed April 23, 2019. http://mitigatehazards.com/ napa-county-mjhmp/.

Napa County 2019. Napa County Emergency Operations Plans. Concept of Operations Base Plans. Accessed April 23, 2019. https://www.countyofnapa.org/905/ Emergency-Operations-Plans.

Agenda Item #6.2.

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3.9 HYDROLOGY AND WATER QUALITY

3.9.1 Introduction
This section evaluates the potential effects on hydrology and water quality associated with development of the proposed Hunter Subdivision Project (Proposed Project), including mitigation measures recommended to avoid or minimize significant impacts where feasible. The information provided describes the hydrology and water quality conditions of the Project site and surrounding area, as well as the applicable federal, state, and local regulations pertaining to protection of hydrology and water quality.

Comments received from the public in response to the Notice of Preparation included concerns about pesticide runoff impacts to the Napa River, flood hazards (e.g., Federal Emergency Management Agency [FEMA] zones and/or levee failure) and impacts to groundwater supplies.

These issues are all addressed in this section. A copy of the Notice of Preparation and comments received is included in Appendix A.

Information and analysis within this section is based on a review of site plans, City of St. Helena (City) planning documents, Napa County’s Watershed Information & Conservation Council, as well as information from federal and state water resource agencies, including the FEMA, the U.S.

Geological Survey, the California Department of Water Resources (DWR), the State Water Resources Control Board (SWRCB), and the San Francisco Regional Water Quality Control Board (RWQCB). In addition, this section is based in part on a groundwater basin analysis report for the Napa Valley Subbasin by Luhdorff & Scalmanni Consulting Engineers, a Hydrology Analysis for Hunter Subdivision, St. Helena, California, prepared for the Proposed Project by RSA Engineers and included as Appendix H, a Water Neutral Report included as Appendix J, and a peer-reviewed well capacity and sustainability analysis included as Appendix L.

3.9.2 Environmental Setting
This section describes the existing setting in the Project area and the built environment related to hydrology and water quality.

Regional Climate
Napa County has a Mediterranean climate with mild and relatively wet winters and dry warm summers. The average high temperature during the summer months (June through September) in Napa County ranges from 80ºF to 89ºF. Average low temperatures during the winter months (December through February) are 36ºF. The City has an annual rainfall of 34.61 inches (WRCC 2016). Snowfall in Napa County is common in some higher elevations, but the majority of precipitation falls as rainfall and any snow accumulation has a limited duration to a few days.

Agenda Item #6.2.

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Watersheds and Hydrology
The Project site is located within the Napa River watershed. The watershed drains an area of approximately 426 square miles within Napa County and defines the western border of Napa County. The watershed’s boundaries are marked by Mount St. Helena to the north (north of Calistoga); the Mayacamas Mountains to the west; Howell Mountain, Atlas Peak, and Mount George to the east; and the Napa-Sonoma Marsh to the south. The Napa River runs through the center of the watershed on the valley floor, draining numerous tributaries along a 55 mile stretch from the headwaters of Mt. St. Helena to the San Pablo Bay.

The northern edge of the Proposed Project site is located approximately 500 feet southwest of the Napa River, on a flat alluvial floodplain formed by the river and its tributaries. Important tributaries to the Napa River in the City include York Creek, which discharges into the Napa River approximately a one mile further upstream from the Project site, and Sulphur Creek, which discharges into the Napa River, approximately a quarter-mile further downstream. The County of Napa (County) has subdivided the Napa River watershed in numerous subwatersheds, 1 based on a high-resolution topography dataset completed in in 2002 (i.e., Light Detection and Ranging data processed by National Center for Airborne Laser mapping at UC Berkeley). These subwatersheds are shown in Figure 3.9-1, Surface Water Hydrology. The Proposed Project is located in the Napa River – Upper St. Helena Reach subwatershed, which is 1,985 acres in size and covers the portion of the Napa Valley floor northwest of the Pope Street bridge and south of the confluence of Canon Creek with the Napa River. Figure 3.9-1 also shows the Sulfur Creek and York Creek subwatersheds.

The Project site is relatively flat with a gentle slope towards its northwestern corner. As part of the City’s Comprehensive Flood Protection Project (Flood Protection Project), described in more detail below), a levee was completed in 2011, just west and north of the Project site which separates the site and nearby residences from the Napa River (see Figure 3.9-1). Existing storm drainage infrastructure includes a detention basin on City-owned property adjacent to the northern boundary of the Project site, a bypass storm drain that routes stormwater collected in the City's conveyance system to a low-flow channel that discharges to the Napa River, and existing storm drains along Hunt Avenue and Del Rio Court. Based on existing topography shown on the Proposed Project’s Tentative Map, drainage onsite occurs as sheet flow towards the north-northeast within the majority of the site, and to the northwest within the northern fifth of the site. Drainage is directed to a shallow swale at the northwestern corner of the site that connects to an offsite City detention basin.
1 Napa County refers to the subdivision of the Napa Valley watershed as “basins.” However, to avoid confusion with groundwater basins, these surface water basins are referred to herein as subwatersheds.

Agenda Item #6.2.

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Hunter Subdivision Project
SOURCE: Bing Maps 2019, USGS 2019 (National Hydrography Dataset), City of St. Helena 2018 0 500 1,000Feet
FIGURE 3.9-1
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Levees
Contours (5 foot)
Index Contours (25 foot)
Streams and Rivers
Perennial Stream/River
Intermittent (Seasonal) Stream/River
Watersheds
Canon Creek
Meadowood Creek
Napa River - Lower St. Helena Reach
Napa River - Upper St. Helena Reach
Sulphur Creek - Main Fork
Sulphur Creek - North Fork
York Creek
Watershed Boundaries
Off-Site Detention Basin
and Discharge Structure
St. Helena Comprehensive
Flood Protection Project Levee
Former (Filled) Pond Area
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The detention basin, which is on the inboard or southeastern side of the levee, is drained by a levee culvert that is designed, under low- to moderate-flow conditions, to discharge stormwater by gravity flow into the Napa River. During high flood events, the water level in the Napa River will rise to an elevation that prevents storm water from draining the residential area by gravity alone. During high flood elevation, the levee culvert gate is closed, routing stormwater into the detention basin. As water fills the basin, the pump station is activated and water is pumped from the basin into the Napa River. The pump station is equipped with a back-up diesel generator in case electricity fails during a storm event. The levee culvert and discharge structure is shown in Figure 3.9-1.

Flood Hazards
The Project site is located adjacent to the southside of the Napa River and just upstream of the confluence of the Napa River and Sulphur Creek. Numerous damaging floods have been recorded since 1862 on the Napa River. The 15 most recent serious floods along the Napa River occurred in 1942, 1943, 1955, 1962, 1963, 1965, 1967, 1973, 1978, 1982, 1983, 1986, 1995, 1997, 1998 and 2005. Prior to 2019, the last four major floods to affect the City’s reach of the Napa River occurred in 1986, 1995, 1997, and 2005, with peak discharges estimated to be 20,000 cubic feet per second (cfs), 21,000 cfs, 16,000 cfs, and 18,000 cfs, respectively (City of St. Helena 2012). None of the floods in recent memory have reached the threshold for a 100- year flood event (Napa County 2013). During the December 2005 event, flood waters entered the Project site and backed up against a low cinder block wall on the north side of the road along Del Rio Court (the wall is oriented east to west). The peak water level for the Napa River in the portion that passes through the City reached 21.61 feet in 2005 and is estimated to have been a 25- to 50-year flood event (USGS 2006). More recently in February 2019, a flood event occurred where flood waters rose to just under one-foot of predicted levels. Flood waters were able to be contained and handled with improved Flood Control Projects along the Napa River within the City of Napa and St. Helena (Napa Valley Register 2019). The 2019 flood event recorded a discharge of 9,570 cfs and a river depth of 19.5 feet on the Napa River at the St.

Helena gauge located roughly 150 feet downstream of the Pope Street bridge crossing (Napa County FCWCD 2019).

FEMA Special Flood Hazard Areas
Flood zones identified on FEMA Flood Insurance Rate Maps (FIRMs) are identified as a Special Flood Hazard Areas (SFHAs) and “other areas of flood hazard.” A SFHA is defined as the area that would be inundated by a flood event having a 1% chance of being equaled or exceeded in any given year. The 1% annual-chance flood is also referred to as the base flood or 100-year flood, and is the national standard used by all federal agencies for the purposes of requiring the purchase of flood insurance and regulating new development. “Regulatory floodways” are areas Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-6
within the SFHA that include the channel of a river/watercourse and adjacent land areas and are expected to have the deepest and highest velocity flooding. In an unobstructed condition, the regulatory floodway can discharge a 100-year flood/base flood without any increase in water surface elevations. The area outside the floodway, but still within the 100-year floodplain can be obstructed without increasing the base flood elevation by more than 1 foot at any point. FEMA considers “other areas of flood hazard” as including areas with a 0.2% annual chance of flooding (i.e., the 500-year flood zone), and areas with reduced risk due to a levee. SFHAs are considered high risk flood areas, whereas other areas of flood hazard are considered low- to moderate-risk areas.

St. Helena Comprehensive Flood Protection Project
After passage of Measure A in 1998, the City and the Napa County Flood Control and Water Conservation District initiated a joint study of potential flood protection projects for the City and nearby County areas. After much study, hydraulic analysis, environmental review, project redesign based on funding constraints, and public input, the scope and design of the City’s Flood Protection Project was defined. The Flood Protection Project encompassed a one mile stretch of the Napa River from Adams Street to Pope Street. The goal of the project was to remove a large portion of the northeastern part of the City from the SFHA, and to enhance the hydrology of the river by returning the floodplain to a more natural state. The project included the following:
• A new levee and floodwall
• A floodwater storage area referred to as Terrace B
• Removal of 17 homes
• Rerouting of drainage along Starr Avenue into a new storm drain outside the new levee • A design standard that provides flood protection from a 200-year event This Flood Protection Project included the area north of the Project site. The project was designed and supervised by a private sector and public agency qualified engineers. These included the City, U.S. Army Corps of Engineers, several engineering consultants, the County, and FEMA.

In December 2005, the City began the permit application process to implement the Flood Protection Project. While the permitting work was underway, the City submitted a Conditional Letter of Map Revision application to FEMA. A Conditional Letter of Map Revision is FEMA's comment on a proposed project that would, upon construction, affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway and the effective SFHA. It indicates whether the project, if built as proposed, would be Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-7
recognized by FEMA. In a letter from FEMA, dated November 2007, it was determined that the submitted data of the project used to create a FIRM for the project area was sufficient and met the minimum floodplain management criteria (FEMA 2012).

Subsequently, construction on the Flood Protection Project started in May 2009. The major structural components of the Flood Protection Project were completed in April 2011; the main levee is shown in Figure 3.9-2, FEMA Flood Hazard Zones. In December 2011, the City submitted an application for a Letter of Map Revision (LOMR) from FEMA. LOMRs are generally based on the implementation of physical measures that affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway or the SFHA. A LOMR officially revises the FIRM or Flood Boundary and Floodway Map, and sometimes the Flood Insurance Study report, and when appropriate, includes a description of the modifications. Once a complete LOMR application is submitted, FEMA has 90 days to review the application and issue the LOMR. FEMA completed its review of the LOMR and officially revised the FIRM to remove the Project site from being within the SFHA. The effective date of the revised FIRM is November 5, 2012 (FEMA 2012).

On-Site Flood Hazards
As shown in Figure 3.9-2 and for the reasons described above, the Project site is not within a SFHA, but is mapped as being in an area with reduced flood risk due to a levee (FEMA 2012).

The base flood elevation for the Napa River in the vicinity of the Project site is 220 feet above mean seal level (amsl), whereas the top of the levee is at least 222 feet amsl. The levee transitions to a flood wall adjacent to the Vineyard Valley mobile home park to the south/southeast of the Project site that provides for the same level of protection. The base flood elevation in the vicinity of the stream gauge used for measuring the discharge and height of the Napa River, which is located downstream of the Pope Street bridge, is 216 feet amsl (FEMA 2012; Napa County FCWCD 2019).

FEMA does not have a mapping category for a 200-year flood, but maps areas with a 0.2% annual chance of flooding (i.e., the 500-year flood zone) along with areas of reduced risk due to levee as “other areas of flood hazard.” By being within an area of reduced risk due to levee, the Project site is considered mapped within the 500-year flood zone (FEMA 2012). Based on the levee design, the Project site would be subject to a flood exceeding a 200-year recurrence interval, equivalent to less than a 0.5% annual chance. During such a flood, the style of flooding onsite would be slow and gradual, since the high velocity flows remain limited to the regulatory floodway. No portion of the Project site is located within the FEMA regulatory floodway. Since the FEMA FIRM has been officially revised through a LOMR, the Project site is not subject to any floodplain development restrictions (FEMA 2012).

Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-8
Flooding Due to Levee Failure or 200-Year Flood Event
The Napa River is subject to significant floods, but the Project site is protected by a recently built levee that is designed to provide a 200-year level of flood protection. The Proposed Project does not include any element that exacerbates existing flood hazards for offsite properties or the general public (i.e., through floodplain encroachment that blocks or redirects flood flows, or by placing habitable structures in areas with a reasonable risk of flooding). Because the Project site is outside of a FEMA SFHA, no flood insurance would be required. However, because there remains residual risk of flooding from catastrophically large floods (such as a 500-year flood) or levee failures, residents in flood-prone areas, even if outside of a regulatory flood zone, have the option to purchase optional flood insurance (i.e., FEMA preferred risk policy).

When levees and floodwalls are used for flood protection, particularly when they protect land uses sensitive to flooding (e.g., residences), overtopping of the levee or floodwall is a source of public concern. The City’s Flood Protection Project, specifically the levee and floodwall along the Napa River and Sulphur Creek, was constructed to provide protection from a 200-year flood event while maintaining an adequate amount of freeboard. The standard design level of protection is for the 100-year flood event; however, the 200-year design basis was implemented to provide an additional factor of safety and to account for potential settlement, changes in channel roughness, and potential channel aggradation. The elevated height of the levee and floodwall (i.e., a 200-year level of protection vs. a 100-year level of protection) along with the freeboard further reduces the potential for overtopping of the levee or floodwall during extreme flood events. The flood control system was also evaluated for stability during a seismic event and was found to be stable (Mead & Hunt, MBK Engineers, and Kleinfelder 2006).

The levee constructed as part of the Flood Protection Project was designed and constructed in accordance with all applicable U.S. Army Corps of Engineers Engineering Manuals and has been reviewed by FEMA. Geotechnical investigations and hydraulic analysis were performed to provide a basis for the design. The flood control facility design was prepared by the City’s engineering team and stamped by the primary designer Mead & Hunt. Design considerations included the post- ProposedProject channel hydraulics and stability. The flood control facilities are operated and maintained by the City in accordance with an operation and maintenance manual approved by FEMA, and in accordance with U.S. Army Corps of Engineers standards. This includes requirements for annual inspections and patrols during flood events. Specifically, levee maintenance consists of bi-annual (spring & fall) levee side mowing and levee embankment inspection prior to the rainy season, immediately following a high-water event, and at intervals not exceeding three months (City of St.

Helena 2012). The purpose of the inspections are to verify that no unusual settlement or loss of material is occurring, that there are no areas of seepage or boils, that no animal burrows are encroaching upon the levee section, that toe drainage ditches are flowing properly, and that access roads are properly maintained and are graded to drain. Measure A, the local ½ cent flood protection sales tax, has established a fund dedicated to funding future maintenance.

Agenda Item #6.2.

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Hunter Subdivision Project
SOURCE: Bing Maps 2019, FEMA 2012
0 250 500 n Feet
FIGURE 3.9-2
Date: 5/3/2019 - Last saved by: dduverge - Path: Z:\Hydro\Projects\10839 Hunter Subdivision\MXD\Figure3.9-2_FEMA Flood Hazard Zones.mxd Project Boundary
Base Flood Elevations
Levees
FEMA Flood Hazard Zones
Special Flood Hazard Areas
Other Area of Flood Hazard
Regulatory Floodway
1% Annual Chance Flood Hazard

0.2% Annual Chance Flood Hazard
Area with Reduced Risk Due to Levee
Area of Minimal Flood Hazard
(Zone X)
Floodway
(Zone AE)
Zone AE
Zone AE
Zone AE
Area of Minimal Flood Hazard
(Zone X)
Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
Hunter Subdivision Project EIR 10839
September 2021 3.9-10

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Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-11
In addition, the same existing measures implemented to respond to flood emergencies within the region would continue to be used and would serve to provide residents with the means to avoid personal harm in the event of a catastrophic flood. This includes flood watches, advisories, and warnings from the National Weather Service, reporting by local news outlets, announcements and communications via Integrated Public Alert and Warning System, text alerts, and other means of communication that would be increasingly used in the event of a severe flood threat (Napa County 2013).

The Napa County Office of Emergency Services releases informational brochures and updates regarding flood preparedness throughout the year and prior to the rainy seasons. The County also has an application (NIXLE) for smartphones (android and apple) so residents within the County can download and receive emergency information during extreme weather events. The Napa Valley Regional Rainfall and Stream Monitoring System’s website (https://napa.onerain.com/home.php) also has Napa County real-time rainfall and river-stream data available for the public to use during inclement weather. Updates are posted by the Napa County Flood Control and Water Conservation District through a serious of interactive web applications to show river and stream flow, and Napa River Flood Forecasts. During extreme weather, these applications and emergency resources, in addition to emergency broadcasts systems, are designed to give ample warning to residents and business owners of flood hazards and to help them prepare for evacuations.

When a flood hazard is imminent or occurring, the local police get involved in assisting with evacuations as necessary. Table 3.9-1 provides a reference for Napa River’s flood stages along with the National Weather Service alerts that the National Weather Service field office releases to partner agencies and the press. The table is meant to illustrate the levels of warning received and the general types of alerts issued or actions taken. For reference, the 2019 flood approached, but did not exceed the moderate flood stage, and the 2005 flood approached, but did not exceed the major flood stage. Because every flood event is different, preparedness and response actions may differ, and are the responsibility of local, county and state offices of emergency management.

Table 3.9-1
Napa River Flood Stages at St. Helena (at Pope Street Bridge) Flood Category River Stage1
National Weather Service Alerts and/or County
OES/Emergency Response Actions
Proposed
Project Impact
Action / Monitor
Stage
16 feet (207.71 feet
amsl)
The Monterey field office of the National Weather Service may issue a Flood Watch-based products to cover Napa
Valley regional flood potential at this stage. Advisory products released to the press.

None
Agenda Item #6.2.

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September 2021 3.9-12
Table 3.9-1
Napa River Flood Stages at St. Helena (at Pope Street Bridge) Flood Category River Stage1
National Weather Service Alerts and/or County
OES/Emergency Response Actions
Proposed
Project Impact
Minor 18 feet (209.71 feet
amsl)
Minor flooding of low-lying agricultural areas along river begins. Low lying rural residential areas immediately
adjacent to the river and some secondary roads affected.

Voluntary evacuation orders are issued. Mandatory
evacuations considered.

None
Moderate 20 feet (211.71 feet
amsl)
Moderate flooding of the lower portions of Silverado Trail along the reach. Inundation of low-lying residential areas along the east river bank in the vicinity of Pope Street Bridge. Secondary and many primary roads inundated;
most major cross roads inundated and unsafe to pass.

Evacuation orders enforced and potentially expanded.

Rescue operations initiated if necessary.

None
Major 22 feet (213.71 feet
amsl)
Major flooding throughout the upper Napa Valley with
many roads adjacent to Napa River inundated, making
travel extremely difficult and unsafe. Evacuation,
emergency response and rescue operations continue.

None
Catastrophic (100-
Year Flood)

24.29 (216 feet
amsl)
Places within FEMA SFHAs become inundated. Residents
advised/ordered
to evacuate.
200+ Year Flood
and/or levee failure
> 24.29 (218 feet
amsl)
Evacuation, emergency response and rescue operations
continue.

Property flood
damage likely.

Sources: Napa County 2013, Napa County FCWCD 2019, NWS 2019.

Note: Elevation in feet (amsl)
The modern design and construction of the levee, along with the City’s ongoing inspection and maintenance of the levee paid for through local sales taxes, substantially reduces its potential to fail in a 200-year flood or in the event of an earthquake. Furthermore, in highly unlikely catastrophic situations (< a 0.5% annual chance) where the levee may be overtopped or in a 200+ year flood event, Proposed Project residents would have ample warning to evacuate prior to flooding. Based on a comparison of the base flood elevation to proposed lot pad elevations, flooding of Proposed Project lots would range between 0 and 5 feet in depth, with the deepest flooding occurring on the northern part of the Project site. This level of flooding would leave upper floors or residences available for refuge. Because of this, the risks from a 200+ year flood and/or levee failure are limited to property damage rather than risk of life. As previously indicated, this would be an impact of the pre-existing environment on the Proposed Project rather than the Proposed Project’s impact on the environment.

Finally, no portion of the Project site is located within an area that would be subject to flooding due to a dam failure. As shown in the St. Helena 2019 General Plan, Draft Environmental Impact Report (EIR), the northern portion of the Project site is mapped as being within the dam failure hazard zone for the Bell Canyon Dam (City of St. Helena 2018). However, the portion of this dam inundation Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-13
zone where the Project site is located is outdated. The dam inundation flood zone is less extensive than the former SFHA as it existed prior to completion of the Flood Protection Project. Therefore, the levee, which was designed to protect against a 200-year flood, would also protect the site against the threat of inundation from failure of the Bell Canyon Dam.

Sea Level Rise, Tsunami Inundation, and Seiche
The Project site is not subject to sea level rise, tsunami inundation and/or seiche wave. The preconditions necessary for a project to be at risk of such hazards is that it be located within a reasonable distance and elevation relative to a coastline (for sea level rise or seiche) or large body of water (for seiche waves). The Project site is located over 200 feet amsl in elevation and not next to a large water body subject to seiche.

Groundwater Resources
Groundwater Basin Status
The Project site is located within the Napa Valley Subbasin (DWR Basin No. 2-002.01, Subbasin) of the Napa-Sonoma Valley Groundwater Basin as designated by the State DWR (DWR 2019a). Napa County further subdivides the Subbasin into groundwater subareas. The Project site is located within the Napa Valley Floor St. Helena subarea (LSCE 2016). In accordance with eight components in the California Water Code Section 10933(b), DWR is required to prioritize
2 all of the groundwater basins across California in order to determine which provisions of the California Sustainable Groundwater Management Act (SGMA) apply to the basins. The latest phase of DWR’s basin re-prioritization (completed in December 2019) the Napa Valley Subbasin was changed from a medium to a high priority ranking (DWR 2019a).

The increase in priority designation for the Napa Valley Subbasin in 2019 was due primarily to revised projections of future population for the Subbasin, an increased assessment of the total number of wells, and a revised approach to evaluating water quality in the Subbasin compared to the previous prioritization analysis performed in 2014. The change from medium priority to high priority does not affect applicable SGMA requirements for the Napa Valley Subbasin.

An extensive analysis of the groundwater Subbasin associated with compliance with SGMA (discussed further below) examined basin conditions, established sustainability goals, and developed minimum thresholds and measurable objectives necessary to track progress towards those goals. One of the central components of SGMA is the definition of six groundwater sustainability indicators, that if found to be causing significant and unreasonable effects throughout the Subbasin, would indicate that the basin is not being managed sustainably. The 2 DWR’s priority rating is based on estimates of population density, anticipated growth, well density, the amount of irrigated agriculture, the degree to which water demands are met from wells (versus surface water), and the existence of documented impacts (e.g., overdraft) (DWR 2014).

Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-14
sustainability indicators are (1) chronic lowering of groundwater levels, (2) reduction in groundwater storage, (3) seawater intrusion, (4) degraded water quality, (5) land subsidence, and (6) depletions of interconnected surface water.

Based on an extensive analysis of historical monitoring data on groundwater levels, groundwater in storage, groundwater quality, and interconnections between groundwater and surface water, there have been no basin-wide significant and unreasonable effects with regard to chronic lowering of groundwater levels, reduction in groundwater storage, seawater intrusion, degraded water quality, and land subsidence (LSCE 2016). The basin analysis report found that groundwater levels in the Napa Valley have been stable over the hydrologic base period (1988- 2015), and the prior historical period where data are available, with recognition that groundwater levels in some areas have been lower during dry water year types (LSCE 2016). A sustainable yield analysis was conducted which established that the maximum amount of water that can be withdrawn annually from the Subbasin groundwater supply without causing an undesirable result ranges between 17,000 and 20,000 acre-feet per year (AFY) (LSCE 2016). From 1988 through 2018, the cumulative annual storage changes in the Napa Valley Subbasin were 4,388 acre-feet, reflecting a basin in balance and the absence of long-term depletions of groundwater storage within the Subbasin (LSCE 2021). The 2020 annual report updated the total amount in storage of the Napa Valley Subbasin to 196,651 acre-feet which is a decrease from the year prior due to a very dry year; however, the report concluded that the basin continues to be managed sustainably despite the most recent fluctuation (LSCE 2021).

Overall, the groundwater table in the alluvial aquifer of the Subbasin is quite shallow; groundwater elevations in the center of the valley fluctuate seasonally approximately 10 to 25 feet, and near the edge of the valley fluctuate approximately 25 to 35 feet (LCSE 2016). The basin analysis report found that the magnitude of the surface water components, particularly inflows from uplands runoff and surface water outflow as well as groundwater baseflow, demonstrate that large quantities of water move through the Subbasin in most years as compared to the amounts of water pumped from the Subbasin or flowing out of the Subbasin as subsurface outflow (LCSE 2016). As a result, sustainability indicators have been set to provide minimum thresholds and measurable objectives for a number of indicator wells throughout the basin with the purpose of maintaining existing conditions with regard to sustainability of the Subbasin. These groundwater level thresholds are also used as measures to provide protection of other undesirable results defined by SGMA.

Napa County releases annual reports that provide an update on basin conditions and makes recommendations necessary to continue to maintain and improve sustainable management.

The most recent annual report finds that most of the groundwater levels in the wells measured have remained above minimum thresholds, however seven wells did record groundwater levels below their minimum thresholds including a well near the Project site (see discussion below).

Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-15
However, these thresholds are monitored for evidence of chronic declines and not necessarily as an isolated exceedance, as the annual report still determined that the Subbasin has continued to be managed sustainably through 2020 (LSCE 2021).

Local Groundwater Uses and Users
The Project site contains an inactive groundwater well adjacent to proposed Lot 19 in the northern portion of the property identified as Parcel B (see Figure 2-4, Proposed Tentative Map, in Chapter 2, Project Description). This well may have been historically used to provide construction water for the earth moving activities associated with the City’s Flood Protection Project and may have been used in the past for agricultural irrigation. The existing condition of the well is considered inactive; however, as it was not being used at the time the Notice of Preparation was released. The Phase I Environmental Site Assessment completed for the Proposed Project noted that the well was inoperable at the time of the site visit (Appendix G).

Table 3.9-2 shows well completion report records available for each township and range section that intersects the Project site, including information on the number and type of wells with records, and their average depth (and range of depths). The well types predominantly consist of domestic and irrigation supply wells but include several municipal/public supply wells. Table 3.9- 2 shows that average well depths for domestic wells tend to be shallower than irrigation and municipal supply wells; this tendency exists because agricultural and especially municipal supply wells require higher yields. The locations of well completion reports are shown in Figure

3.9-3, Napa Valley Groundwater Subbasin, although many well records exist which have not yet been mapped by DWR, or only been mapped to the centroid of the township and range section within which the well is located. Furthermore, the existence of a well completion report does not indicate whether or not the well is currently active.

Based on review of the well completion report records, there are numerous domestic and irrigation wells located on the northeastern side of the Napa River, as well to the north and west of the Project site whose locations are not shown in Figure 3.9-3 (DWR 2019b). The primary municipal use of groundwater is for the City, which occurs from two wells on the south side of Stonebridge Park (Stonebridge Complex wells) completed at depths of 410 and 670 feet below ground surface (bgs) (Figure 3.9-3). As opposed to rural residential and agricultural uses, who draw from wells distributed throughout the Subbasin, the groundwater portion of the urban water demand for the City’s whole water service area is drawn from the two City wells at the Stonebridge Complex.

Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-16
Table 3.9-2
Well Completion Report Records on the Project Site and Vicinity Township &
Range Section
Domestic
Well
Count
Average
Well
Depth, in
Feet
(Range)
Production
/ Irrigation
Well Count
Average
Well Depth,
in Feet
(Range)
Municipal
/ Public
Well
Count
Average
Well Depth,
in Feet
(Range)
Average
Well Yield,
in GPM
(Range)1
T08NR06W25 19 280
(120 – 460)
18 390
(160 – 780)
2 670
(560 – 780)
96 (7- 500)
T08NR05W30 18 351
(100 – 860)
14 376
(247 – 580)
2 360
(285 – 435)
147
(8 – 1,000)
T08NR05W31 12 307
(165 – 450)
23 423
(195 – 820)
5 437
(232 – 600)
68 (10 – 250)
T08NR06W36 26 349
(120 – 780)
34 367
(55 – 610)
0 N/A 39
(2 – 250)
Source: DWR 2019a.

Notes: GPM = gallons per minute
1 Well yields are only reported for a subset of well completion reports in the database, and all types of wells (i.e., domestic, agricultural and municipal wells). Actual yield depends on well construction details, well use/purpose, and pumping equipment installed at the time of well log submittal.

Local Groundwater Levels
DWR well completion reports and the DWR SGMA data viewer were reviewed for groundwater level information pertaining to the Project site and its vicinity (DWR 2019b-c). Groundwater level monitoring sites are shown in Figure 3.9-3, and includes two locations where groundwater levels are currently monitored, including a dual-completion monitoring well near the Pope Street crossing of the Napa River (Well ID 222s-swgw5 and 223d-swgw5), and a well on the southern side of the City (DWR 2021). Other monitoring sites have historical data or no data. The dual-completion monitoring well is one of the many representative monitoring sites throughout the Subbasin that are used to track compliance with minimum thresholds and measurable objective established under SGMA.

The Project site’s proximity to the Napa River means that groundwater levels on-site are likely to be relatively shallow but may seasonally lower during the late summer and fall. Groundwater levels measured in the shallow screen of a dual-completion monitoring well (Napa River at Pope Street) have fluctuated between 18 and 25 feet bgs between 2015 and 2020 (shallow screen). The latest available groundwater level reading in Spring 2020 was 20 feet bgs (192 feet amsl) for the shallow screen and 24 feet bgs (188 feet amsl) for the deep screen (DWR 2021). However, the Fall 2020 groundwater level measurement was 61 feet bgs (156 feet amsl) which is below the threshold of 164 amsl. These groundwater levels reflect seasonal peaks and also indicate that 2020 was a very dry year, but generally the seasonal highs and lows have remained fairly stable throughout the well’s period of record (2015 to 2020). Based on the groundwater contour maps prepared for the 2020 annual groundwater report, the direction of groundwater flow in the vicinity of the City is to the east and south, to varying degrees based on the time of year (LSCE 2021).

Agenda Item #6.2.

Date: 4/24/2019 - Last saved by: mwatson - Path: Z:\Projects\j1083901\MAPDOC\EIR\Hydro\Figure3.9-3_Groundwater Basins.mxd Napa Valley Groundwater Subbasin
Hunter Subdivision Project
SOURCE: Bing Maps 2019, USGS 2019 (National Hydrography Dataset), DWR 2019 01 900 ,800
Feet
FIGURE 3.9-3
Date: 4/24/2019 - Last saved by: mwatson - Path: Z:\Projects\j1083901\MAPDOC\EIR\Hydro\Figure3.9-3_Groundwater Basins.mxd Project Boundary
Napa Valley Groundwater Subbasin (No. 2-002.01)
Township and Range Sections
Well Completion Report Locations
Contours (25 foot)
DWR Groundwater Level Monitoring
Irrigation
Observation
Residential / Domestic
Streams and Rivers
Perennial Stream/River
Intermittent (Seasonal) Stream/River
Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-18

INTENTIONALLY LEFT BLANK
Agenda Item #6.2.

3.9 – HYDROLOGY AND WATER QUALITY
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September 2021 3.9-19
The Subbasin monitoring well may be within the pumping influence zone of the Stonebridge Complex wells, which supplies the entire City with up to 20% of its water demand in average years, and up to 30% in dry years (City of St. Helena 2018). Between 2006 and 2019, annual groundwater pumping at these two wells has averaged 350 AFY, ranging from a low of 182 acre-feet in 2012 to a high of 526 acre-feet in 2013 (LSCE 2016, 2020). As shown in Figure 3.9- 3, the City’s Stonebridge Complex is located approximately 0.5 miles southwest of the Proposed Project’s on-site well, and approximately 600 feet from the Subbasin monitoring well.

Given the proximity and similar setting, groundwater levels are expected to be similar or possibly shallower beneath the Project site. According to the findings of the well capacity and sustainability report (Appendix L), the existing agricultural well on the site (proposed to be located in Parcel B on the tentative map) was constructed in 1976 to a depth of 410 feet bgs; with a yield of 350 gallons per minute (gpm). The screened portions of the well are from 80 feet bgs to the total depth of the well at 410 feet bgs. Groundwater was first encountered during drilling for the initial installation of the well at a depth of 24 feet bgs (Appendix L). At the time of the recent well capacity and sustainability test for the onsite well, the groundwater level was at 22 feet bgs. It is anticipated this well would be used to irrigate all on-site (public and private) landscape areas, which includes the existing vineyard in the panhandle portion of the site, lawns, and sidewalk planting strips.

Water Quality
Water quality in surface and groundwater bodies is regulated by the SWRCB and RWQCBs.

The Project site is under the jurisdiction of the San Francisco Bay Regional Water Quality Control Board (San Francisco RWQCB), which is responsible for the implementation of state and federal water quality protection statutes, regulations, and policies in the vicinity of the Project site. The San Francisco RWQCB implements the Water Quality Control Plan (Basin Plan), a master policy document for managing water quality in the region (San Francisco RWQCB 2017).

As previously mentioned, runoff from the Project site would be directed to the off-site detention basin adjacent to the Napa River. Therefore, under normal circumstances, runoff from the Proposed Project would either be lost to evaporation or percolate into the underlying groundwater table. Under extreme flood scenarios, surface water would be discharged to the Napa River once the capacity of the City’s off-site detention basin is reached. Therefore, the receiving waters for the purpose of water quality consist of both groundwater and the Napa River.

Surface Water Quality
The water quality of the Napa River is highly variable and changes significantly depending on the specific reach of the river, the time of year, and the level of flow existing at any one time.

Agenda Item #6.2.

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General water quality indicators (e.g., pH, DO, temperature, specific conductance) within the Napa River generally decline as flows recede in late summer, and reach seasonal lows just before the first rains of the season. On April 6, 2018, the U.S. Environmental Protection Agency (EPA) approved California’s 2014–2016 List of Impaired Waters which replaces the previous 2012 California Clean Water Act (CWA) Section 303(d) List as California's current 303(d) List (SWRCB 2019). The Napa River is included on the CWA Section 303(d) list of water quality limited segments due to impairment3from nutrients, pathogens, and sedimentation/siltation, further discussed below under “Regulatory Setting” (SWRCB 2019).

Total Maximum Daily Load (TMDL)4 allocations have been developed for sediment and pathogens, but development of a TMDL for nutrients is in progress. The sediment and pathogen TMDLs has been completed by the San Francisco RWQCB and the TMDLs have been incorporated into the Basin Plan as an amendment (San Francisco Bay RWQCB 2017). The Basin Plan amendment includes water quality targets for pathogen indicators Escherichia coli (E. coli), fecal coliform, and total coliform, as well as density-based (load) limits for these pathogen indicators. The most common sources of pathogens are wastes from warm-blooded animals, including humans, livestock, domestic pets, and wildlife. Different types of land use have different run-off concentrations of nutrients, organic matter, and bacteria. Predominant land uses include agriculture, residential, commercial, industrial, mixed (variety of land uses), transportation, open space, forest, and wetlands; the loadings from agricultural activity are likely the most dominant. The Basin Plan amendment also includes waste load allocations for individual municipal dischargers including on-site sewage disposal systems, sanitary sewer systems, municipal stormwater runoff, grazing lands, and confined animal feeding operations (San Francisco Bay RWQCB 2017).

The San Francisco RWQCB also adopted a Basin Plan amendment incorporating a TMDL for sediment and a Habitat Enhancement Plan for the Napa River. The amendment includes numeric targets for spawning gravel permeability and streambed scour. The TMDL also includes load allocations (for non-point sources) for land areas upstream and downstream of dams, in addition to waste load allocations for urban runoff and wastewater discharges. This Basin Plan amendment was approved in November 2009. The Basin Plan finds that more than half of the sediment loads in the Napa River are from human processes, which include road construction, surface erosion from agricultural lands, and the hydromodification impacts of urban stormwater runoff (San Francisco Bay RWQCB 2017).
3 Being impaired (also known as “water quality-limited”) means that a water body is “not reasonably expected to attain or maintain water quality standards” without additional regulation. 4 A TMDL specifies the maximum amount of a pollutant a water body can receive and still meet water quality standards.

Agenda Item #6.2.

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In addition to the above, the City is subject to the TMDL for diazinon and pesticide-related toxicity applicable to all San Francisco Bay Area urban creeks, which was incorporated as a Basin Plan amendment in 2005 (San Francisco Bay RWQCB 2017). The TMDL imposes toxicity targets for urban creek water and sediment, and a diazinon concentration target for urban creeks. TMDL targets shall be achieved through regulatory programs, education and outreach, and research and monitoring. The TMDL attainment strategy will primarily focus on integrated pest management and the use of less toxic pest control methods. The EPA phased out urban diazinon applications at the end of 2004; however, replacements for diazinon (such as pyrethroids) may now pose potential water quality and sediment concerns.

The adopted TMDLs discussed above contain water quality standards in the form of waste load allocations that quantify the amount of pollutants that may be discharged into an impaired water body from various contributing sources, in addition to water quality objectives for receiving waters. This includes water quality standards for urban runoff (and wastewater discharges) with which the City must comply. One strategy used by local urban runoff management programs to move toward achieving TMDL standards is to identify the sources of TMDL pollutants in urban runoff and then to implement control measure programs for these pollutants.

In the urban parts of the City, potential contaminants of concern could include motor oil and other contaminants from vehicle parking on streets and driveways, as well as pesticides and fertilizers from vineyards and residential landscaping. Stormwater from the Project vicinity that does not percolate into the ground is collected within the City’s storm drainage system and ultimately discharged into the Napa River. There are records of the use of agricultural pesticides at the Project site that have been applied to the vineyard. Records obtained from the Napa County Agricultural Commissioner’s Office include the use of herbicides, fungicides and miticides (Appendix G). According to the aerial photograph review in Appendix G, the property was the site of an orchard in the 1940s which was removed by 1968. By 1973, vineyard cultivation appears in the southwest part of the site. When used properly in accordance to product labels, pesticides degrade with time and repeated irrigation and are minimally applied only where necessary. Nevertheless, the potential exists for residual contaminants within surface soils to become suspended and carried in stormwater runoff, and those contaminants can affect receiving waters and areas downstream.

Groundwater Quality
The Basin Plan establishes beneficial water uses for groundwater basins within the region. The Napa Valley groundwater subbasin underlies the Project site and is listed in the Basin Plan as providing the beneficial uses of municipal and domestic water supply (MUN), industrial process water supply, industrial service water supply (IND), and agricultural water supply (AG).

Agenda Item #6.2.

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Groundwater quality throughout most of the Napa Valley region is generally suitable for most urban and agricultural uses, with only local impairments occurring. The primary constituents of concern are total dissolved solids, nitrate, boron, and organic compounds. The City’s groundwater source (Stonebridge Complex wells) is treated to remove iron and manganese and are chlorinated prior to entering the City’s distribution system.

The SGMA Basin Analysis Report completed by Napa County provides the following summary of groundwater quality conditions occurring throughout the Subbasin (LSCE 2016):

Groundwater quality records from representative monitoring sites provide information on important constituents whose concentrations influence the quality of water for irrigation and human consumption. Despite a typical lack of historical groundwater quality records in Napa County, available data suggest that groundwater is generally of good quality throughout most subareas. Poor groundwater quality does, however, exist in the south and the north-central parts of the County. The poor groundwater quality includes concentrations of naturally occurring metals such as arsenic, iron, and manganese that exceed drinking water standards throughout the county. Naturally occurring elevated levels of boron are also prevalent in most subareas. Subareas south of the Napa Valley Floor, such as the Carneros and Napa River Marshes, have poor quality water due to naturally elevated levels of salinity and chloride. The Calistoga Subarea of the Napa Valley Floor also has poor quality water in many wells due to hydrothermal conditions resulting in higher concentrations of metals. Nitrate concentrations are not a concern throughout the county, but tend to be somewhat higher in agricultural areas in the Napa Valley Floor.

Water quality standard exceedances in the Subbasin were limited to the naturally occurring constituent arsenic, with 4 of 26 sites showing maximum concentrations above the arsenic maximum contaminant level of 10 μg/L, including one site within the St. Helena subarea (LSCE 2016). The groundwater quality testing attached to the Proposed Project’s on-site well completion report indicated elevated levels of iron and manganese (DWR 1992). The City’s two active groundwater wells are treated to maintain Title 22 standards, including chlorination prior to entering the City’s distribution system (City of St. Helena 2018). Potable water supply is discussed in more detail in Section 3.13, Utilities and Service Systems.

3.9.3 Regulatory Setting
The regulatory framework related to hydrology and water quality is extensive, because it addresses issues related to the environment (i.e., maintaining high quality waters for waterdependent species and activities), public health (e.g., ensuring adequate drinking water quality), Agenda Item #6.2.

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and public safety (e.g., avoiding flood damage). Impacts pertaining to provision of potable and non-potable water supplies, including applicable regulations, are addressed in Section 3.13, Utilities and Service Systems.

Federal Regulations
Clean Water Act
The CWA (33 USC 1251 et seq.), as amended by the Water Quality Act of 1987, is the major federal legislation governing water quality. The objective of the CWA is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” Important sections of the act are as follows:
• CWA Sections 303 and 304 provide for water quality standards, criteria, and guidelines.

Under Section 303(d) of the CWA, the State of California is required to develop a list of impaired water bodies that do not meet water quality standards and objectives.

California is required to establish TMDLs for each pollutant/stressor. A TMDL defines how much of a specific pollutant/stressor a given water body can tolerate and still meet relevant water quality standards. The impairments applicable to the Proposed Project’s receiving waters are described in Section 3.9.2 (Water Quality). • CWA Section 401 (Water Quality Certification) requires an applicant for any federal permit that proposes an activity which may result in a discharge to waters of the United States, to obtain certification from the state that the discharge will comply with other provisions of the act. The Project site does contain potentially jurisdictional wetlands, and this issue is addressed in Section 3.4 (Biological Resources). • CWA Section 402 establishes the National Pollutant Discharge Elimination System (NPDES), a permitting system for the discharge of any pollutant (except for dredged or fill material) into waters of the United States. This permit program is administered by the SWRCB and the nine RWQCBs, who have several programs that implement individual and general permits related to construction activities, stormwater runoff quality, and various kinds of non-stormwater discharges. The City operated under the Small Municipal Separate Storm Sewer (MS4) Permit from the SWRCB and all projects in the City are required to comply with the MS4 Permit requirement that address stormwater runoff discharges to a water of the United States (i.e., the Napa River and the northern San Francisco Bay).
• CWA Section 404 establishes a permit program for the discharge of dredged or fill material into waters of the United States. This permit program is jointly administered by the U.S. Army Corps of Engineers and the EPA. The Project site does contain potentially jurisdictional wetlands, as addressed in Section 3.4 (Biological Resources).

Agenda Item #6.2.

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Numerous agencies have responsibilities for administration and enforcement of the CWA. At the federal level this includes the EPA, the U.S. Army Corps of Engineers, the Bureau of Reclamation, and the major federal land management agencies such as the U.S. Forest Service and the Bureau of Land Management. At the state level, with the exception of tribal lands, the California EPA and its sub-agencies, including the SWRCB, have been delegated primary responsibility for administering and enforcing the CWA in California.

Federal Antidegradation Policy
The federal antidegradation policy is designed to protect water quality and water resources. The policy directs states to adopt a statewide policy that includes the following primary provisions:
(1) existing instream uses and the water quality necessary to protect those uses shall be maintained and protected; (2) where existing water quality is better than necessary to support fishing and swimming conditions, that quality shall be maintained and protected unless the state finds that allowing lower water quality is necessary for important local economic or social development; and (3) where high-quality waters constitute an outstanding national resource, such as waters of national and state parks, wildlife refuges, and waters of exceptional recreational or ecological significance, that water quality shall be maintained and protected.

National Flood Insurance Program
The National Flood Insurance Act of 1968 established the National Flood Insurance Program to provide flood insurance within communities that were willing to adopt floodplain management programs to mitigate future flood losses. The National Flood Insurance Act also required the identification of all floodplain areas within the United States, and the establishment of flood-risk zones within those areas. FEMA is the primary agency responsible for administering programs and coordinating with communities to establish effective floodplain management standards.

FEMA is responsible for preparing FIRMs that delineate the areas of known special flood hazards and their risk applicable to the community. The program encourages the adoption and enforcement by local communities of floodplain management ordinances that reduce flood risks.

In support of the program, FEMA identifies flood hazard areas throughout the United States on FEMA flood hazard boundary maps.

State Regulations
Porter-Cologne Water Quality Control Act
The Porter–Cologne Act (codified in the California Water Code, Section 13000 et seq.) is the primary water quality control law for California. Whereas the CWA applies to all waters of the United States, the Porter–Cologne Act applies to waters of the state, which includes isolated wetlands and groundwater in addition to federal waters. It is implemented by the SWRCB and Agenda Item #6.2.

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the nine RWQCBs. In addition to other regulatory responsibilities, the RWQCBs have the authority to conduct, order, and oversee investigation and cleanup where discharges or threatened discharges of waste to waters of the state5 could cause pollution or nuisance, including impacts to public health and the environment.

The act requires a “Report of Waste Discharge” for any discharge of waste (liquid, solid, or otherwise) to land or surface waters that may impair a beneficial use of surface or groundwater of the state. California Water Code Section 13260 subdivision (a) requires that any person discharging waste or proposing to discharge waste, other than to a community sewer system that could affect the quality of the waters of the state, to file a Report of Waste Discharge with the applicable RWQCB. For discharges directly to surface water (waters of the United States), an NPDES permit is required, which is issued under both state and federal law; for other types of discharges, such as waste discharges to land (e.g., spoils disposal and storage), erosion from soil disturbance, or discharges to waters of the state (such as groundwater and isolated wetlands), Waste Discharge Requirements (WDRs) are required and are issued exclusively under state law. WDRs typically require many of the same best management practices (BMPs) and pollution control technologies as required by NPDES-derived permits.

Water Quality Control Plan for the San Francisco Bay Basin The SWRCB provides state-level coordination of the water quality control program by establishing statewide policies and plans for implementation of state and federal regulations. The nine RWQCBs throughout California adopt and implement Basin Plans that recognize the unique characteristics of each region with regard to natural water quality, actual and potential beneficial uses, and water quality problems. The San Francisco Bay RWQCB is responsible for the protection of the beneficial uses of waters draining to the San Francisco Bay, including the Project site. The Water Quality Control Plan for the San Francisco Bay Basin (Region 2) (Basin Plan) designates beneficial uses, establishes water quality objectives, and contains implementation programs and policies to achieve those objectives for all waters addressed through the plan (California Water Code Sections 13240–13247) (San Francisco Bay RWQCB 2017).

General NPDES Permits and WDRs
To enable efficient permitting under both the CWA and the Porter–Cologne Act, the SWRCB and the RWQCBs run permit programs that group similar types of activities that have similar threats to water quality. These “general permit” programs include the Phase II Small MS4 Permit, the construction general permit, the industrial general permit and other general permits for low-threat discharges. The construction stormwater program, the small MS4 permit program, 5 “Waters of the state” are defined in the Porter–Cologne Act as “any surface water or groundwater, including saline waters, within the boundaries of the state” (California Water Code, Section 13050(e)).

Agenda Item #6.2.

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and the general permit for low-threat discharges are administered by the SWRCB, while other general WDRs are administered by the San Francisco Bay RWQCB. Table 3.9-3 lists the waterquality-related permits that would apply to the Proposed Project, each of which is further described below. General WDRs and/or NPDES permits contain effluent limitations that may be stricter than basin-wide water quality objectives, because they regulate specific categories of discharge and are designed to limit the cumulative effects of development over broad areas.

Table 3.9-3
State and Regional Water Quality-Related Permits and Approvals Program/Activity
Order Number/ NPDES
Number Permit Name Affected Area
Construction stormwater
program
2009-0009-DWQ/
CAS000002, as amended
NPDES General Permit for Storm Water
Discharges Associated with Construction
and Land Disturbance Activities
(Construction General Permit)
Statewide
Phase II Small MS4
Program
SWRCB Water Quality
Order 2013-0001-DWQ/
CAS000004, as amended
Waste Discharge Requirements for
Stormwater Discharges from Small
Municipal Separate Storm Sewer
Systems (Small MS4 Permit)
All Regulated Small
MS4 systems; New
Development and
Redevelopment
Projects within the
City of St. Helena.

Temporary/low volume
dewatering1
SWRCB Water Quality
Order 2003-0003-DWQ
Statewide General Waste Discharge
Requirements for Discharges to Land
with a Low Threat to Water Quality
Statewide
Notes: NPDES = National Pollutant Discharge Elimination System; MS4 = municipal separate storm sewer system; WDR = Waste Discharge Requirement 1 If any dewatering is required.

Source: Appendix H.

Construction General Permit (SWRCB Order 2009-0009-DWQ, as amended) For stormwater discharges associated with construction activity in the State of California, the SWRCB has adopted the General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities (Construction General Permit) to avoid and minimize water quality impacts attributable to such activities. The Construction General Permit applies to all projects in which construction activity disturbs 1 acre or more of soil. Construction activity subject to this permit includes clearing, grading, and disturbances to the ground, such as stockpiling and excavation. The Construction General Permit requires the development and implementation of a Stormwater Pollution Prevention Plan (SWPPP), which would include and specify water quality BMPs designed to prevent pollutants from contacting stormwater and keep all products of erosion from moving off site into receiving waters. Routine inspection of all BMPs is required under the provisions of the Construction General Permit, and the SWPPP must be prepared and implemented by qualified individuals as defined by the SWRCB. The Proposed Agenda Item #6.2.

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Project applicant must submit a Notice of Intent to the SWRCB to be covered by a NPDES permit and prepare the SWPPP prior to the beginning of construction.

Various levels of soil disturbances associated with Proposed Project construction are anticipated to occur over the majority of the Project site, which is about 17 acres; therefore, the Proposed Project would require coverage under the Construction General Permit.

Phase II Small Municipal Separate Storm Sewer System Permit (SWRCB Order 2013-0001- DWQ, as amended)
As part of Phase II, the SWRCB adopted a statewide General Permit for the Discharge of Storm Water from Small MS4s (Water Quality Order No. 2013-0001-DWQ, General Permit No.

CAS000004) (Small MS4 Permit) to provide permit coverage for smaller municipalities, including non-traditional small MS4s such as military bases, public campuses, and prison and hospital complexes. The Small MS4 Permit requires development and redevelopment projects to adhere to the Small MS4 Permit and follow published guidance for compliance.

Sustainable Groundwater Management Act
The Sustainable Groundwater Management Act (SGMA) is a package of three bills (Assembly Bill 1739, Senate Bill 1168, and Senate Bill 1319) that provides local agencies with a framework for managing groundwater basins in a sustainable manner. The SGMA establishes standards for sustainable groundwater management, roles and responsibilities for local agencies that manage groundwater resources, and priorities and timelines to achieve sustainable groundwater management within 20 years of adoption of a Groundwater Sustainability Plan (GSP). Central to the SGMA are the identification of critically over-drafted basins and the prioritization of groundwater basins, establishment of Groundwater Sustainability Agencies (GSAs), and preparation and implementation of GSPs for medium priority, high priority and critically overdrafted basins. GSAs must be formed by June 30, 2017. GSPs must consider all beneficial uses and users of groundwater in the basin, as well as include measurable objectives and interim milestones that ensure basin sustainability. A basin may be managed by a single GSP or multiple coordinated GSPs.

At the state level, DWR has the primary role in the implementation, administration, and oversight of the SGMA, with the SWRCB stepping in should a local agency be found to not be managing groundwater in a sustainable manner. DWR recently approved regulations and guidelines for implementation of the SGMA. Under SGMA, Section 10733.6, a local entity (or entities) can pursue an alternative to a GSP provided that certain sustainability objectives are met. An alternative to a GSP may include “[a]n analysis of basin conditions that demonstrates that the basin has operated within its sustainable yield over a period of at least 10 years” (Section 10733.6(b)(3)). In response to SGMA, Napa County prepared a Basin Analysis Report Agenda Item #6.2.

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for the Napa Valley Subbasin, per the requirements of Water Code Section 10733.6 (b)(3).

While the Basin Analysis Report analyzes areas outside the Subbasin to determine how those areas affect recharge and runoff in the Subbasin, the areas outside the Subbasin are not subject to SGMA. The Basin Analysis Report (LSCE 2016c) was submitted to DWR on December 16, 2016 in compliance with SGMA. On November 13, 2019, DWR issued a final determination to not approve the Basin Analysis Report.

Basins in which the submitted alternative was not approved by the DWR must comply with the same planning deadlines applicable to other high- and medium-priority basins under SGMA.

GSAs in these basins must submit a GSP by January 31, 2022. Following DWR’s decision to not approve the Basin Analysis Report, the Napa County Board of Supervisors acted on December 17, 2019 to become a GSA for the Napa Valley Subbasin and declare their intent to develop a GSP for the Subbasin by January 31, 2022.

Local Regulations
City of St. Helena 1993 General Plan
The City’s 1993 General Plan Public Health and Safety Element and Public Facilities Element has the following guiding policies that apply to flood hazards and storm drainage/flooding.

Flood Hazards
Policy 8.6.1: Prohibit the introduction of intensive urban development into designated Flood Hazard Areas.

Policy 8.6.3: Prohibit the construction of structures or flood barriers which would unnaturally divert flood waters or would increase flood hazards in other areas.

Policy 8.6.4: Require a grading permit for any filling, grading, or dredging that may increase potential for flood damage.

Policy 8.6.7: Encourage the use of Flood Hazard Areas within new development areas for open space and recreation uses, including parks and greenbelts.

Policy 8.6.8: Ensure that any new development that is allowed within the floodplain is constructed so that the lowest floor elevation is at least one foot above the l00-year flood level.

Agenda Item #6.2.

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Storm Drainage/Flooding
Policy 9.4.1: New development should provide adequate drainage improvements to handle generated storm runoff from the site to the nearest major watershed. The watersheds include York Creek, Sulphur Creek and the Napa River.

Policy 9.4.2: If a City storm drain is available, the developer should participate in the funding to the extent it benefits the development.

Policy 9.4.3: Extension of existing downstream drains which have adequate capacity should be completed at the developer's expense with future reimbursement for oversizing costs at the time of connection by others.

Policy 9.4.4: Grading and earth filling within the designated l00-year floodway should not be permitted except for public streets or bridges.

Policy 9.4.5: Encroachments into the 100-year floodway should not result in any increase in flood levels during the occurrence of the base flood discharge.

Policy 9.4.6: Standards for subdivisions should include the following:
a. All preliminary subdivision proposals shall identify the flood hazard area and the elevation of the base flood.
b. All final subdivision plans will provide the elevation of proposed structure(s) and pads.

If the site is filled above the base flood, the final pad elevation shall be certified by a registered civil engineer or surveyor and provided to the floodplain administrator. c. All subdivision proposals shall be consistent with the need to minimize flood damage. d. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage. e. All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The City’s 2019 General Plan Public Health and Safety Element and Public Facilities Element has the following guiding policies that apply to flood hazards and storm drainage/flooding.

Flood Hazards/Drainage
Policy PS5.1: Minimize the risk to people, property and the environment caused by flooding hazards. Site new development to minimize potential damage from a 100-year flood.

Agenda Item #6.2.

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Continue to require that any new development is constructed FEMA standards. Prohibit the siting of uses within Flood Hazard Areas inconsistent with FEMA standards that could result in health and safety hazards, including those due to the release of chemicals or other substances as a result of inundation or erosion. Ensure that any new flood protection projects comply with federal and State standards.

Policy PS5.6: Coordinate with the Napa County Flood Control and Water Conservation District and other responsible agencies to maintain protocols and funding for the regular inspection and maintenance of flood control facilities in the city, including levees, floodwalls, floodplain terracing, stormwater detention ponds, and pumping facilities.

Policy PF3.1: Ensure that new developments provide adequate drainage improvements and detention to mitigate flooding from increased stormwater runoff attributable to the development.

Policy PF3.C: Consistent with Municipal Code Section 16.32.170, continue to prohibit the creation of new residential lots that will be subject to periodic inundation from floodwaters.

New development proposals on existing lots of record must identify flood hazard areas and mitigate all impacts to base flood levels and potential flood damage from grading filling and construction through proper drainage, construction, and location of utilities, in accordance with FEMA requirements.

Policy PF3.E: At the time of development review, require that post-project runoff be limited to pre-project peak flow rates for the five-year and ten-year storms as a condition of approval (See also Climate Change Element, Topic Area 4).

Groundwater
Policy PF1.D: The City of St. Helena should not draw or sell any groundwater beyond that currently allowed until a safe yield of the groundwater system has been identified through a study of the North Main Basin Aquifer by a qualified hydro geologist.

Policy PF1.E: Permit no new development relying on groundwater unless and until it is determined that the incremental production of ground water to support the development will not adversely impact the water production capability of the aquifer supporting the City wells.

Policy PF1.F Track the drilling of new private wells in and around St. Helena and, if so recommended by the qualified hydrologist hired by the City’s water system, request that the County impose a moratorium on new well drilling if needed to protect the production capability of the City wells.

Agenda Item #6.2.

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St. Helena Municipal Code
The City’s Municipal Code, “Public Services,” includes Chapter 13.32, which contains the City’s Stormwater and Runoff Pollution Control Ordinance. This ordinance empowers the City’s Public Works Department to enforce stormwater pollution regulations, including:
• Prohibiting illicit discharges to the stormwater conveyance system; • Establishing minimum requirements for stormwater management, including source control requirements, to prevent and reduce pollution;
• Establishing requirements for development project site design to reduce stormwater pollution and erosion;
• Establishing requirements for the management of stormwater flows from development projects, both to prevent erosion and to protect and enhance existing water-dependent habitats; and
• Establishing standards for the use of off-site facilities for stormwater management to supplement on-site practices at new development sites.

Title 15, Buildings and Construction, includes Chapter 15.52, Flood Damage Protection. This chapter contains the City's flood damage control provisions. It includes standards for permitting and construction within established flood hazard zones, and gives the City Engineer the authority to administer, implement, and enforce floodplain management regulations through the review and approval of development applications. Chapter 15.52 specifies that all “new construction and substantial improvement of any residential structure shall have the lowest floor, including basement in AE, AH and Al -A30 Zones, elevated to 18 inches above the base flood elevation.” Title 16, "Subdivisions," includes Chapter 16.32, Design Standards and Improvements includes Section 16.32.070, Drainage, which requires stormwater runoff from subdivisions to be collected and conveyed by an approved storm drainage system. The storm drainage system shall be designed by a registered civil engineer for ultimate development of the watershed and shall be capable of collecting and conveying runoff generated by the ten-year flood. The system shall provide for the protection of abutting and off-site properties that may be adversely affected by any increase in runoff attributed to the development; off-site storm drain improvements may be required to satisfy this requirement. In addition, retention ponds, drainage swales and/or check dams may be required to reduce off-site peak storm flow generated by projects to the historic flow.

Title 17, Zoning, includes Section 17.88.030, Subdivisions, which requires that all subdivision proposals and other proposed new developments be reviewed by the City engineer to assure that (1) all such proposals are consistent with the need to minimize flood damage; (2) all public utilities and facilities, such as sewer, gas, electrical and water systems are located, elevated, Agenda Item #6.2.

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and constructed to minimize or eliminate flood damage; and (3) adequate drainage is provided so as to reduce exposure to flood hazards.

Section 17.88.050, FEMA Requirement, which requires that new construction or replacement of existing construction be in conformance with the standards and regulations of the FEMA.

City Stormwater Management Standards
The City has developed stormwater management standards that apply to discretionary and ministerial projects submitting an application for a use permit, building permit, and/or grading permit. The standards include both a construction and post-construction phase review and permitting process implemented by the City’s Public Works Department. If a project is subject to construction-phase requirements, the applicant must prepare an Erosion Control Plan for sites of less than 1 acre and a SWPPP for sites of 1 acre or more. The plans must depict BMPs that will be implemented during construction to eliminate or minimize the discharge of pollutants.

The City’s Public Works Department conducts site inspections to evaluate the effectiveness of the construction-phase BMPs using the following performance standards:
• No measurable increase of pollution (including but not limited to sediment, concrete and stucco, automotive fluids, hazardous materials, and pathogens) in runoff from the site; • No slope erosion; and
• Water velocity moving off-site must not be greater than pre-construction levels.

If a project is subject to post-construction requirements, the applicant must submit a Stormwater Control Plan to the Public Works Department. The Stormwater Control Plan must demonstrate compliance with the Bay Area Stormwater Management Agencies Association PostConstruction Manual. This Stormwater Control Plan must illustrate how the project is implementing low-impact development principles and providing for long-term BMP maintenance.

3.9.4 Impacts
Methods of Analysis
Impacts with respect to hydrology and water quality are assessed by comparing conditions expected to occur associated with development of the site relative to the existing environmental setting described above. Post-Proposed-Project hydrology is assessed using the hydrology report prepared for the Proposed Project by the applicant’s consultant, included as Appendix H, as well as preliminary Proposed Project plans (e.g., grading plan, erosion control notes, and utility plan) and a review of the Proposed Project’s water demand and compliance with the City’s water neutrality ordinance (Appendix J, Water Neutral Report). In addition, a well capacity and Agenda Item #6.2.

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sustainability assessment was performed on the agricultural well at the Project site which included a 24-hour well pump test consistent with industry standards. The findings of the well capacity and sustainability assessment were independently reviewed by an independent California Licensed Engineering Geologist, whose peer review was documented in a letter report dated September 9, 2021 (Appendix L). In this case, the only discretionary approvals the Proposed Project applicant is requesting at this time is approval of a Tentative Subdivision Map.

Future approvals, including Design Review and a Use Permit required to construct attached multifamily units, would be required prior to any development of the site.

The analysis considers impacts on hydrology, water quality, flooding and groundwater resources in the context of broader issues and concerns affecting the region. The study area for surface water hydrology is the Napa River - Upper St. Helena Reach subwatershed, which is part of the large Napa River watershed, and the study area for groundwater resources is the Napa Valley Groundwater Subbasin. Actions required to implement the City’s general plan policies related to hydrology and water quality, as enforced through the Municipal Code and the development approval process, are considered as components of the Proposed Project in the evaluation of impacts.

Thresholds of Significance
Consistent with Appendix G of the California Environmental Quality Act Guidelines, a significant impact would occur if development of the Proposed Project would do any of the following:
• Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality.
• Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin.
• 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:
o Result in substantial erosion or siltation on- or off-site; o Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site;
o Create of contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; or
o Impede or redirect flood flows.

Agenda Item #6.2.

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• In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation. • Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan.

Threshold Criteria not Applicable to the Proposed Project Due to the location and characteristics of the Proposed Project, certain elements of the significance criteria above are not applicable and therefore, are not considered potential impacts. These criteria elements are addressed briefly below and are not discussed further in this document.

Alteration of a Stream or River
The Proposed Project would not alter the course of a stream or river because none are encompassed by the Proposed Project boundary. The Proposed Project would not substantially alter the general pattern and/or direction of stormwater runoff because it does not propose substantial modifications to topography (the site is and would remain nearly level), and because runoff would continue to be directed to the north and northeast. Storm runoff from the site would be collected by a series of catch basins in the streets and conveyed to the City’s off-site detention basin through underground storm drain lines. Therefore, Impact 3.9-3 (below) addresses the potential for alteration of existing drainage patterns through the increases in the rate or volume of runoff from impervious surfaces, but not through modification of the course of a stream or river. This issue (third significance threshold listed above) is not further addressed.

Tsunami or Seiche
Furthermore, the preconditions necessary for a project to be at risk of hazards due to a tsunami, or seiche require a reasonable distance and elevation relative to a coastline (for sea level rise or seiche) or large body of water (for seiche waves). The Project site is located over 200 feet amsl in elevation and is not next to a large water body subject to seiche. Therefore, there be no impact (or risk) associated with a tsunami or seiche and this issue (fourth significance threshold listed above) is not further addressed.

Impacts and Mitigation Measures

3.9-1: Would the Proposed Project violate water quality standards or waste discharge requirements, or otherwise substantially degrade surface or groundwater quality? This impact would be less than significant.

Agenda Item #6.2.

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Construction
Development of the Project site would involve up to 16.9 acres of soil disturbance over the course of Proposed Project construction. During this time, the most intensive soil disturbance would occur during site preparation and earthmoving activities associated with grading, installation of underground utilities, foundation and building pad construction, and road and streetscape construction. During this period, soil erosion may result in discharges of sedimentladen stormwater runoff into nearby receiving waters. As discussed in the setting (and shown in Figure 3.9-1), the Project site drains to an existing City-owned detention basin that was constructed as part of the City’s Flood Protection Project. Therefore, during construction, the detention basin would be the most immediate storm runoff destination during construction.

However, the detention basin has a low-flow outlet, meaning that runoff from the construction site could eventually enter the Napa River.

The primary potential pollutant associated with construction activity is sediment (i.e., high turbidity) generated from site preparation and grading activities. Since the Napa River is listed under CWQ Section 303(d) as impaired for sedimentation/siltation, it has an increased sensitivity to impacts associated with turbid runoff. In addition to sediment, other pollutants associated with construction activity could include heavy metals, oil/grease, fuels, trash and other pollutants from accidental spills or releases of refuse, paints, solvents, sanitary wastes, and concrete curing compounds.

Furthermore, as a portion of the site has been historically used as a vineyard and before that an orchard, there is the possibility that soils could contain residual agricultural pesticides or elevated nutrient levels. However, the potential for residual pesticides to remain on-site is low because pesticides are required to demonstrate a lack of persistence in the environment considerably beyond their intended period of use in order to obtain EPA approval. Furthermore, when pesticides are used properly and in accordance with label specifications, potential impacts on the surrounding environment and receiving waters (surface water and groundwater) are minimized.

Historically, pesticides degrade with time as repeated rainy seasons flush soils and further dilute residual concentrations. When compared to agricultural land uses, which can include occasional ripping, plowing, and replanting and use of unpaved roads, which continuously leave bare soils exposed to storm runoff, residential land uses have a lower impact with regard to dispersion of fertilizers and/or pesticides into the environment.

Without adequate precautions, construction activities could generate pollutants and/or mobilize sediment such that it contributes to water quality degradation of receiving waters and/or violates Basin Plan objectives. However, compliance with the Construction General Permit and the City’s Stormwater and Runoff Pollution Control Ordinance (Chapter 13.32) would require implementation of a SWPPP to address potential construction-related impacts on water quality.

The SWPPP must specify the location, type, and maintenance requirements for BMPs necessary to prevent stormwater runoff from carrying construction-related pollutants into the Agenda Item #6.2.

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Napa River and/or the underlying groundwater basin. BMPs must be implemented to address potential release of fuels, oil, and/or lubricants from construction vehicles and equipment (e.g., drip pans, secondary containment, washing stations); release of sediment from material stockpiles and other construction-related excavations (e.g., sediment barriers, soil binders); and other construction-related activities with the potential to adversely affect water quality. The SWPPP must also include a construction site monitoring program that identifies specific requirements for dry weather visual observations of pollutants at all discharge locations, and as appropriate (depending on the Risk Level), sampling of the site effluent and receiving waters.

The number, type, location, and maintenance requirements of BMPs to be implemented as part of the SWPPP depend on site-specific risk factors such as soil erosivity, construction season/duration, and receiving water sensitivity.

SWPPPs must be developed and implemented by a Construction General Permit Qualified SWPPP Developer (QSD)/Qualified SWPPP Practitioner (QSP). The QSD/QSP is tasked with determining the receiving water risks (including beneficial uses and CWA Section 303d impairments), monitoring site activities that could pose risks to water quality, and developing a comprehensive strategy to control construction-related pollutant loads in site runoff. Based on the Proposed Project characteristics and the setting, the SWPPP would be required to meet risk level II or III requirements as defined in the Construction General Permit. Minimum standard BMPs include erosion and sediment controls; site management/ housekeeping/waste management; management of non-stormwater discharges; run-on and runoff controls; and BMP inspection, maintenance, and repair activities. A rain event action plan must also be prepared by the QSD/QSP to outline the procedures to prepare the construction site for rain events and minimize the potential release of construction-related contaminants. It is at the discretion of the QDS/QSP to use as many BMPs as available which would successfully protect on- and off-site resources from erosion, sedimentation, and pollution.

The following list includes examples of treatment control BMPs commonly employed during construction; although these would vary based on the nature of construction activities, the characteristics of the site, and the existing receiving waters impairments (these features would appear as notes on any final design plans):
• Silt fences installed along limits of work and/or the construction site • Stockpile containment (e.g., visqueen, fiber rolls, gravel bags) • Exposed soil stabilization structures (e.g., fiber matrix on slopes and construction access stabilization mechanisms)
• Street sweeping
• Tire washes for equipment
Agenda Item #6.2.

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• Runoff control devices (e.g., drainage swales, gravel bag barriers/chevrons, velocity check dams) and slope protection.
• Drainage system inlet protection
• Wind erosion (dust) controls
• Tracking controls
• Prevention of fluid leaks (inspections and drip pans) from vehicles • Dewatering operations best practices
• Materials pollution management
• Proper waste management
• Regular inspections and maintenance of BMPs
The standard requirements contained in a SWPPP are sufficient to address a project’s potential to violate water quality standards or waste discharge requirements. Implementation of SWRCB and San Francisco Bay RWQCB requirements (CWA NPDES Program and Porter–Cologne Water Quality Control Act WDRs) are enforced through the City’s Stormwater and Runoff Pollution Control Ordinance (Chapter 13.32). In addition to stormwater runoff, construction activities can generate fugitive dust, which if not properly controlled, can be deposited in nearby waters. Note that this potential impact is addressed in Section 3.3, Air Quality; actions to mitigate adverse effects on air quality would likewise mitigate potential adverse effects on water quality from atmospheric deposition.

The construction-related impact of the Proposed Project on water quality would be less than significant, because compliance with existing permitting requirements and conditions of approval are sufficient to avoid water quality degradation, meet water quality standards and Basin Plan objectives, and prevent adverse effects on beneficial uses.

Operation
Implementation of the Proposed Project would include the development of impervious surfaces, including roadways and driveways, and structures (dwellings) which would impede water infiltration and contribute to increased water runoff rates. These increased water runoff rates could gather potential pollutants such as heavy metals, nutrients from lawn fertilization, oil/grease and fuels from areas where vehicles are parked, and other household trash and debris. Stormwater runoff would have the potential to pollute nearby surface waters if storm drain infrastructure and buffers would not be used.

Agenda Item #6.2.

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Constituents found in urban runoff vary as a result of differences in rainfall intensity and occurrence, geographic features, the land use of a site, as well as vehicle traffic and percent of impervious surface. In the Napa Valley, there is a natural weather pattern of a long dry period generally from May to October. During this seasonal dry period, pollutants contributed by vehicle exhaust, vehicle and tire wear, crankcase drippings, spills, and atmospheric fallout accumulate on roadways, driveways, and parking lots within the urban watershed. Precipitation during the early portion of the wet season (which typically spans from November to April) washes these pollutants into the stormwater runoff, which can result in elevated pollutant concentrations in the initial wet weather runoff (first flush).

The Proposed Project would be subject to the most recent standards and performance criteria contained in the Small MS4 Permit (described in Section 3.9.3, Regulatory Setting). The City is subject to this permit because it makes discharges to the Napa River from its municipal storm drain system. The Small MS4 Permit requires development and redevelopment projects to adhere to the Small MS4 Permit and follow published guidance for compliance. These include the following:
• Site Design Measures: Site design measures requires early assessment and evaluation of how site conditions, such as soils, vegetation, and flow paths will influence the placement of buildings and paved surfaces. The evaluation is used to meet the goals of capturing and treating runoff and maximizing opportunities to mimic natural hydrology.

Options for site design measures include preserving trees, buffering natural water features, and using green roofs or porous pavement.
• Source Control Measures: Source control measures seek to avoid introduction of water quality pollution/degradation altogether. Source control strategies include things like covering refuse/trash areas, properly managing outdoor storage of equipment/materials, minimizing use of pesticides and fertilizers in landscaping, using sumps or special area drains to send non-stormwater discharges to the sewer, ensuring regular grounds maintenance, etc.
• Treatment Control Measures: Treatment control measures retain, treat and/or infiltrate the site runoff produced under normal circumstances, controlling both the quality and quantity of stormwater released to the City’s conveyance system or directly to receiving waters. In most situations, this means implementing structural BMPs (e.g., infiltration, bioretention and/or rainfall harvest and re-use) to treat the volume and rate of runoff produced by 85th percentile storm (i.e., design capture volume). • Operation and Maintenance Requirement: The Small MS4 Permit requires that maintenance agreements stay in place with each property (executed and then recorded with the County Clerk Recorder) to ensure permanent treatment control measures Agenda Item #6.2.

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developed on site are properly maintained and/or repaired in accordance with the stormwater quality control plan.

Overall, the Small MS4 Permit requires new development and redevelopment to adopt a lowimpact development strategy, which minimizes hydromodification6 impacts known to have
adverse impacts on receiving waters. The City implements the Small MS4 Permit by requiring developers seeking approval of tentative subdivision maps to comply with MS4 Permit standards and the guidance and criteria in the Bay Area Stormwater Management Agencies Post Construction Manual. Although specific design features have yet to be finalized for the Proposed Project, all of the items above must be included in a Stormwater Control Plan to be submitted to the City as a condition of Proposed Project approval, as described in in the Regulatory Setting section above. The Stormwater Control Plan, to be developed and submitted by the Proposed Project applicant for final Proposed Project approval, must illustrate how the Proposed Project is implementing low-impact development principles and providing for longterm BMP maintenance.

The Proposed Project’s grading plan includes all the elements necessary to demonstrate it can successfully comply with MS4 Permit requirements. Based on the findings in Appendix H, the City’s detention basin is adequately sized to hold the increase in runoff that would be generated by the Proposed Project (further discussed in Impact 3.9-3). It is expected that the detention basin would be used and/or modified, as necessary, to comply with the water quality design capture volume required under the MS4 Permit, the details of which must be included in the Proposed Project’s Stormwater Control Plan. Furthermore, water quality features such as downspouts to landscaped swales; vegetated swales; hydrodynamic oil, water and solid separators; private street sweeping; labeled storm drains (“drains to river”) and homeowner educational materials on stormwater pollution prevention are listed on the grading plan as BMPs to be implemented to prevent storm runoff of poor quality from entering the Napa River or seeping into the underlying groundwater table.

Impacts associated with Proposed Project construction and operation on water quality would be less than significant, because existing permitting requirements and conditions of approval (i.e., MS4 Permit and the City’s Stormwater and Runoff Pollution Control Ordinance) are sufficient to avoid water quality degradation, meet water quality standards and Basin Plan objectives, and prevent adverse effects on beneficial uses. 6 Hydromodification is a primary contributor to problems related to excessive sediment and altered steam flow dynamics (e.g., flow volumes and velocities), primarily due to impervious surfaces, mass grading, and/or poor road designs (both urban and rural/unpaved).

Agenda Item #6.2.

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Mitigation Measures
None required.

3.9-2: Would the Proposed Project decrease groundwater supplies or interfere substantially with groundwater recharge such that the Project may impede sustainable groundwater management of the basin? This impact would be less than significant.

As discussed in detail under the environmental setting (Groundwater Resources), the County works with local jurisdictions including the City to sustainably manage the Napa Valley Groundwater Subbasin in compliance with SGMA. In its most recent assessment of conditions, the County, through its technical consultant, has determined that the Subbasin is not exhibiting significant and unreasonable impacts with regard to the applicable sustainability indicators defined by SGMA, including lowering of groundwater levels, depletion of groundwater in storage, degradation of groundwater quality, and depletions of interconnected surface waters (LSCE 2021). In its most recent annual report, the Subbasin was found to continue to exhibit stable groundwater levels, even despite a very dry 2020 water year, as it has historically, and has continued to be operated within the sustainable yield of the Subbasin (of between 17,000 and 20,000 AFY) (LSCE 2021). The long term (1988–2020) annual change in storage for the Subbasin is a decrease of 8,945 AF, following the very dry conditions of 2020, but still within the ranges that are generally experienced over the long term (LSCE 2021). Annual storage changes have commonly fluctuated between positive and negative values dating back to 1988; however, the median change is a positive increase of 1,784 AF, indicating that groundwater demands are not resulting in depletion of the aquifer (LCSE 2021).

Potential Proposed-Project-related impacts on groundwater depends on the component of its total water demand that would come from on-site or off-site groundwater wells. Based on the Proposed Project applicant’s Water Neutral Report (Appendix J) the Proposed Project is expected to require 37.04 AFY to supply its total water demand (including both domestic and landscape irrigation, see also Section 3.13, Utilities, Table 3.13-10). Out of this total, it is estimated that up to 17.16 AFY (5,592,210 million gallons) would be supplied by the on-site groundwater well (shown in Figure 3.9-3) to provide for irrigation of all public and private landscaping (including lawns and planter strips between the proposed streets and sidewalks) as well as an existing vineyard in the panhandle portion of the site that is slated to remain. The Proposed Project’s landscape irrigation demand was determined by RHA and Spatial Design Group (see Appendix J) using the City’s Model Water Efficient Landscape Ordinance. The analysis uses an annual reference evapotranspiration (ETo) of 44.1 inches established for the City. Actual landscape water use associated with the Proposed Project may be lower but cannot exceed this amount under the City’s model landscape ordinance. The remainder of the Agenda Item #6.2.

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Proposed Project’s water demand (i.e., 19.88 AFY) would be served by the City’s municipal/potable water supply.

Therefore, the groundwater demand associated with the Proposed Project would come from a combination of the onsite well (located on Parcel B – see Figure 2-4 in Chapter 2, Project Description) and the City’s Stonebridge Complex wells (shown in Figure 3.9-3). As discussed in detail in Section 3.13 (Utilities and Service Systems), the City’s municipal water supply system relies on groundwater for, on average, up to 20% of its total supplies (with the remainder coming from a variety of surface water sources). The City relies on its groundwater well to serve as a buffer during drought years, when less surface water is available. It has stated that up to 30% of the City’s demand may be served by groundwater, if necessary, in below normal, dry, and critically dry years. Therefore, it is assumed that between 18% and 30% of the Proposed Project’s domestic water demand could come from the City’s Stonebridge Complex wells. This amounts to 3.98 AFY of Proposed Project demand from the City’s groundwater wells during average years, and up to 5.96 AFY during critically dry years.

The distinction between City water and the on-site well water is important, because the Proposed Project would be required to implement the City’s water neutrality policy (incorporated by reference in Chapter 13.12 [Water Use Efficiency and New Development] of the City’s Municipal Code), in which the Proposed Project must offset the full amount of its City water demand through any combination of on-site water conservation measures, or payment of a fee to be used for implementation of conservation measures for the City’s existing housing stock (such as toilet retrofits or other City approved conservation measures). Because the City’s municipal connections are served by the same combination of water supply sources, including groundwater, this offset would translate to eliminating the Proposed Project’s impact on the City’s municipal groundwater wells. Table 3.9-4 shows the Proposed Project’s demand for City groundwater. Because there may be a delayed effect due to the timing to complete the Proposed Project’s agreed upon offset measures, this impact analysis assumes a (highly unlikely) scenario that the Proposed Project would result in an increase in demand of 3.98 AFY from the City’s groundwater well in an average year.

The Stonebridge Complex wells have produced on average about 350 AFY since 2006, ranging from a low of 182 acre-feet in 2012 to a high of 526 acre-feet in 2013 (LSCE 2016, 2020). The wells have a combined capacity of approximately 595 gallons per minute, which is equivalent to 960 AFY assuming constant pumping. The average municipal groundwater demand of the Proposed Project (3.98 AFY) represents just 1.1% of the groundwater typically pumped from the municipal supply wells. In addition, according to the groundwater basin assessment report, groundwater pumping is a relatively small outflow component compared to surface water stormflows and groundwater baseflow discharged to the Napa River (LSCE 2016). Therefore, the basin groundwater budget is dominated much more by precipitation than it is by Agenda Item #6.2.

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groundwater pumping and the proposed groundwater pumping by the project would be expected to have a negligible effect on flows in the Napa River (LSCE 2016).

Table 3.9-4
Project Demand from City Groundwater Wells During Average and Critically Dry Years Year Percent City Demand Served by Groundwater Proposed Project Demand for City Groundwater1 Average 18% 3.09 AFY
Critically Dry 30% 5.15 AFY
Source: Appendix J.

Note
:
1 Calculated by multiplying the percent (as a fraction) of City groundwater demand per year type by the Proposed Project’s total estimated water demand of 19.88 AFY.

Furthermore, the City’s average groundwater use represents less than 37% of the wells’ combined capacity. Groundwater levels from a dual completion monitoring well located about 600 feet away (SGMA indicator well 222s[/3d]-swgw5, shown in Figure 3.9-3) have been measured on a continuous basis since December 2014. Despite the City’s pumping pattern during this time frame (which includes during drought years), along with the agricultural and domestic pumping that occurs in the vicinity, the groundwater level trend in the monitoring well is stable (LCSE 2021). Marked declines of the groundwater table to a level of up to approximately 30 feet bgs are observed in the summer and fall, but the groundwater table returns to its previous level of approximately 22 bgs by early spring (LSCE 2021).

As discussed in detail in the environmental setting (Groundwater Resources), the dual completion monitoring well is one of the Subbasin’s representative monitoring sites established for measuring whether sustainability goals are being met. The minimum threshold that would indicate a significant and unreasonable lowering of groundwater levels, reduction in groundwater storage, and/or streamflow depletion for the indicator well is 32 feet bgs (equates to 185 feet above mean sea level (amsl)) for the shallow screened well and 53 bgs (164 feet amsl) for the deeper screened well (LSCE 2016). In fall 2019 (when groundwater levels are typically at their lowest), the measured groundwater levels at the indicator well were 29 feet bgs (188 feet amsl) and 46 bgs (171 feet amsl) for the shallow screen and deep screen, respectively (DWR 2020). By Spring 2020, the shallow well had risen to 20.4 feet bgs or 196.6 amsl and the deeper well to approximately 36 feet bgs or 181 amsl (LSCE 2021). Despite heavy pumping to sustain the area’s municipal and agricultural water demands, these levels remain above minimum thresholds set to indicate significant and unreasonable impacts with regard to groundwater sustainability under SGMA. Given the aforementioned factors, a 0.9% increase in the City’s groundwater demand associated with the Proposed Project would not have a measurable impact on the groundwater levels in the vicinity of the Stonebridge Complex wells.

Agenda Item #6.2.

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This would likewise be the case for the Proposed Project’s demand of 17.16 AFY from the onsite well. This water demand comes out to an average pumping rate of 10.6 gpm compared to the well yields of vicinity wells that range from 39 to 147 gpm. The on-site well, proposed to be located on Parcel B of the proposed subdivision, would easily be capable of supplying this amount based on the well’s yield (as reported by the Project applicant) of 350 gpm. Although the well is currently inoperable and would need to be repaired so it is operational, this is also consistent with regional well yields. The recent well capacity and sustainability assessment performed on the agricultural well on the Project site confirmed an ability of the existing well to meet the proposed average pumping rate of 10.6 gpm (Appendix L). In the 24-hour pump test, a pumping rate of 40 gpm was employed and only one foot of drawdown was measured in the well which stayed consistent throughout the pumping period (Appendix L). The immediate recovery of this relatively small drawdown upon cessation of pumping was further evidence of high aquifer transmissivity (i.e., an ability of a water bearing unit to transmit water flow) and relatively abundant groundwater.

As shown in Table 3.9-2, there are a number of municipal and irrigation wells in the vicinity of the Project site, and average well yields far exceed the anticipated demand for the Proposed Project (note minimum well yields listed are for domestic wells constructed for low yield). The aquifer in general is known to be a productive alluvial aquifer, and therefore, there would be sufficient yield available to supply the Project’s well water landscape irrigation demand as also demonstrated by the findings of the site specific well pump test conducted on the existing agricultural well on the Project site. The proposed rate of pumping is relatively low and the resulting radius of influence would be highly localized, and greatly overshadowed by the radius of influence associated with the much higher producing agricultural and municipal supply wells in the surrounding vicinity. The existing surrounding levels of groundwater pumping has not produced undesirable results under SGMA (LSCE 2021) and both regional and local groundwater levels have remained stable; therefore, the potential impact of using the on-site well as proposed would be less than significant.

A review of the existing well indicates that the well is screened from 80 feet bgs to a total depth of 410 feet bgs with a 20-foot seal at the surface. Therefore, the well would draw from the deeper volcanic aquifer, below the Napa Valley alluvium which is considered hydraulicly connected to the Napa River (Appendix L). Therefore, the proposed pumping from this well is not likely to have any direct effect on surface flow in the Napa River. In addition, as stated above, the Subbasin as a whole is being managed sustainably, with a long-term median increase in groundwater storage of 1,784 AFY, therefore the localized impacts on groundwater levels and effects on flows in the Napa River would be minimal, thus the Proposed Project’s overall impacts on groundwater resources would be less than significant.

Agenda Item #6.2.

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Mitigation Measures
None required.

3.9-3: Would the Proposed Project substantially alter the existing drainage pattern of the site or area through the addition of impervious surfaces resulting in erosion or siltation on- or off-site; increasing the rate or amount of surface runoff resulting in flooding on- or off-site; contributing runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide polluted runoff; or impede or redirect flood flows? This impact would be less than significant.

Alterations to drainage patterns would be limited to increases in the rate and volume of storm water runoff associated with impervious surfaces. According to Appendix H, the Proposed Project would result in the addition of 10.91 acres of impervious surface, which is equivalent to an impervious surface coverage of 58%. Increases in the rate and volume of storm water runoff can be associated with exceedance of local storm drain capacity, increases in on- or off-site flooding, and/or hydromodification impacts to receiving waters, which include increase bank erosion or contribution of site-related pollutants. Because the Proposed Project would not alter the course of a stream or river and is not located within the SFHA of the Napa River, it would not impede or redirect flood flows.

In addition, the Project site would be subject to flooding only in a highly unlikely, catastrophic scenario. Because the Proposed Project consists of residences (as opposed to industry or businesses that store appreciable quantities of hazardous materials and/or wastes), the risk of releasing pollutants during such flooding would be low. The residences could have small quantities of household hazardous wastes, and such wastes could be released in a catastrophic flood scenario. However, in the context of such flooding, the release of such waste would not result in measurable increases in pollutant loads carried by the river during such a flood event, and would be dwarfed by the effects caused within the entire watershed.

Potential impacts associated with increases in the rate and/or volume of runoff produced by the Proposed Project are addressed below.

Substantial Erosion or Siltation On- or Off-Site
The off-site City detention basin has been designed with adequate capacity to capture and treat increases in the rate and volume of stormwater runoff associated with development in this area of the City, including development of the Project site with impervious surfaces. Per an agreement with the City and the Comprehensive Flood Protection Project’s Interior Drainage Analysis Final Report for the Miller Property/Hunter Property/Hunt Avenue, it was determined that development of the Flood Protection Project’s detention basin would account for future Agenda Item #6.2.

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development of the Hunter property (Project site) up to 70% impervious surface area (Appendix H). The Proposed Project is estimated to be developed at approximately 58% impervious surface; therefore, allowing the Project site’s increased runoff to be contained within the City’s detention basin without the need to expand the basin or further development of facilities.

As discussed under Impact 3.9-1, the Proposed Project would be subject to the most recent standards and performance criteria contained in the Small MS4 Permit because it would be required to prepare and submit for City approval a Stormwater Control Plan that complies with the Bay Area Stormwater Management Agencies Post Construction Manual. It is expected that the City’s detention basin would be used and/or modified as necessary to comply with the water quality design capture volume required under the MS4 Permit, the details of which must be included in the Proposed Project’s Stormwater Control Plan. Furthermore, water quality features such as downspouts to landscaped swales; vegetated swales; hydrodynamic oil, water and solid separators; private street sweeping; labeled storm drains (“drains to river”) and homeowner educational materials on stormwater pollution prevention are listed on the grading plan as BMPs to be implemented to prevent storm runoff of poor quality from entering the Napa River or seeping into the underlying groundwater table.

The operation-related impact of the Proposed Project on water quality would be less than significant, because compliance with existing permitting requirements and conditions of approval (i.e., MS4 Permit and the City’s Stormwater and Runoff Pollution Control Ordinance) are sufficient to avoid water quality degradation (including erosion and siltation).

Increases in On- or Off-Site Flooding
As previously discussed, the City-owned off-site detention basin has been designed to store the increase in storm water runoff generated from the Project site during a 100-year storm event.

During major flood events, the levee culvert gate is closed, routing stormwater into the detention basin. This avoids contributing to flows within the Napa River. As water fills the basin, the pump station is activated and water is pumped from the basin into the Napa River. However, by the time that occurs, the detention basin would have already captured the increase in flows associated with impervious surfaces on the Project site. For this reason, the impact of the Proposed Project to both on- or off-site flooding would be less than significant.

Stormwater Drainage System Capacity
The Proposed Project would construct storm drains or as required, improve existing storm drains to ensure adequate capacity is available to carry runoff produced by a 10-year storm event. Based on the Proposed Project’s utility plan, on-site storm flows from single-family residences would be conveyed to the off-site detention basin via underground storm drain lines varying in diameter from 15 to 30 inches. Storm runoff from the Project site east of the proposed Agenda Item #6.2.

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Starr Avenue extension (multifamily housing) would be collected by 15-inch storm drains and connected to the City’s existing 36-inch storm drain and would drain into the adjacent detention basin. Title 16 of the City’s Municipal Code requires a new stormwater drainage system be designed by a registered civil engineer for ultimate development of the watershed, and to convey runoff generated by the 10-year flood. Per Title 16, the stormwater drainage system must also be designed to provide for the protection of abutting and off-site properties, and offsite storm drain improvements may be required to satisfy this requirement. Street curbs would be designed to adequately collect and convey the runoff produced by a 100-year storm. As indicated above, the existing off-site detention basin was designed to accommodate runoff from the Project site of up to 70% impervious surface area.

Because compliance with the City’s Municipal Code and improvement standards associated with approval of tentative subdivision maps, and because the off-site detention basin was designed with adequate capacity, the Proposed Project would have a less-than-significant impact related to exceedance of stormwater system capacity.

Mitigation Measures
None required.

3.9-4: Would the Proposed Project conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? This impact would be less than significant.

As discussed under Impact 3.9-1, the Proposed Project would comply with applicable regulations and permits designed to comply with the Water Quality Control Plan for the San Francisco Bay Region. The SWPPP and Stormwater Control Plan to be developed and implemented in compliance with the City’s Municipal Code would be effective at meeting water quality objectives of the Basin Plan. As discussed under Impact 3.8-2, the County is currently achieving sustainable groundwater management under an alternative GSP submittal (Basin Analysis Report). For the reasons discussed therein, the groundwater demand of the Proposed Project would not have an appreciable impact on meeting minimum thresholds established for the Napa Valley Subbasin under SGMA. Therefore, the impact of the Proposed Project on water quality and groundwater management plans would be less than significant.

Mitigation Measures
None required.

Agenda Item #6.2.

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3.9.5 Cumulative Impacts
The cumulative context for the analysis of potential water quality impacts related to surface water is the Upper St. Helena Reach subwatershed (shown in Figure 3.9-1). This is because stormwater discharges originating from this area could combine with those of the Proposed Project to result in an increase in non-point source pollution discharging into the Napa River upstream of Sulphur Creek. Such increases could result from a combination of construction activities, greater use intensity, increased coverage of impervious surfaces and/or increased use of routine household cleaners and landscape chemicals. New development and/or redevelopment projects in these locations have the potential to generate impacts related to the violation of water quality standards, Basin Plan water quality objectives, and/or TMDLs established for the Napa River.

For groundwater resources, the cumulative context is the Napa Valley Groundwater Subbasin (Subbasin) (shown in Figure 3.9-3). Development of past, present and reasonably foreseeable projects within this area that results in an increase in groundwater demand could result in impacts related to depletion of the underlying aquifer, regional lowering of the groundwater table level, or depletions of interconnected surface waters.

As the Proposed Project does not have impacts with regard to flooding (since the potential impact is eliminated through use of the off-site detention basin), it would not contribute to any cumulative flooding impacts in the subwatershed.

3.9.5: Would the Proposed Project cumulatively degrade surface or groundwater quality? The Project’s contribution would not be considerable.

State and regional regulations described in Section 3.9.3 (Regulatory Setting) would reduce the rate of runoff and filter out pollutants in the same or similar manner as described in Impact 3.9-1. Construction activities are required to comply with the SWRCB statewide NPDES stormwater permit program, the Porter-Cologne Act’s requirements for site-specific waste discharge, as well as local agency public works construction standards. In addition, the City’s 1993 General Plan policies, 2019 General Plan policies, and existing City regulations would ensure protection of water quality, improve stormwater management, and reduce stormwater pollution. Increased impervious surface area as a result of the Proposed Project and other development projects in the watershed would be mitigated through application of the Small MS4 Permit, which requires the capture and treatment of stormwater runoff for the 85th percentile storm event. Areas within the cumulative context that are outside the jurisdictional boundary of the City would implement similar measures because Napa County requires development and redevelopment projects to implement the same standards discussed under Impact 3.9-1 (i.e., SWPPP and MS4 Permit standards).

Agenda Item #6.2.

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Based on development of past, present and reasonably foreseeable projects in the Upper St. Helena Reach subwatershed this is an existing potentially significant cumulative impact.

Due to the residential nature of the Proposed Project and compliance with mandatory existing state and local requirements to ensure protection of water quality in the subwatershed the Proposed Project’s contribution to this potentially significant cumulative impact is less than considerable resulting in a less-than-significant cumulative impact.

Mitigation Measures
None required.

3.9-6: Would the Proposed Project cumulatively decrease groundwater supplies or interfere substantially with groundwater recharge such that sustainable groundwater management of the basin would be impeded? The Project’s contribution would not be considerable.

As discussed under Impact 3.9-2, Napa County monitors the groundwater basin and has established minimum thresholds and measurable objectives for the Subbasin, which includes a representative monitoring site near the Pope Street Bridge crossing of the Napa River. The Basin Analysis Report prepared for the Subbasin, indicates that groundwater conditions in the Subbasin are currently meeting sustainability goals established per SGMA and the Subbasin has operated within its sustainable yield over a period of more than 20 years. The Report includes projects and management actions to ensure sustainability targets are met through the planning and implementation horizon of the City’s 2019 General Plan (2040 and beyond) (LSCE 2016). The City’s 2019 General Plan EIR notes that from 2011 through 2015, groundwater drawn from the Subbasin accounted for about 18% of the City’s total water supply (City of St.

Helena 2018). In addition, due to stable groundwater levels observed during recent drought conditions (from 2012 through 2015) it indicates recent rates of groundwater pumping have not exceeded the sustainable yield of the subbasin (City of St. Helena 2018). As noted above under Impact 3.9-2, the Proposed Project’s increase in water demand that would be supplied by groundwater wells would amount to a 0.9% increase which would not have a measurable impact on the groundwater levels in the vicinity of the Stonebridge Complex wells.

Future development in the City is required to comply with existing regulations that would ensure overall infiltration into the aquifer would remain robust, including requiring low-impact development projects be included to capture and infiltrate stormwater runoff, consistent with Bay Area Stormwater Management Agencies Association Manual, City Municipal Code, and required compliance with the NPDES permit, MS4 requirements, and/or General Waste Discharge Requirements. The 2019 General Plan includes policies PF1.E and PF1.F that require tracking new private wells to protect groundwater production. The 2019 General Plan Agenda Item #6.2.

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does not identify a significant cumulative groundwater impact. However, the Napa County General Plan Update EIR (SCH #2005102088), notes increased demand on groundwater supplies associated with increased development in the County (including cities) could lead to groundwater decline and overdraft contributing to a significant cumulative impact on groundwater resources (Napa County 2007).

The City has implemented actions to ensure the groundwater Subbasin continues to operate within its sustainable yield. The City’s 2011 Water Neutral Policy for Development requires all new development to be water-neutral, through a combination of on-site water conservation measures, off-site retrofitting and use of well water, as allowed. Future development in the City is not expected to result in an increase in total water demand because new development is required to offset new demand with water conservation retrofits of existing facilities, or in-lieu payments to the City to carry out any retrofit projects. In addition, as addressed under Impact

3.9-2, the on-site agricultural well is expected to yield 350 gpm (as reported by the Project applicant) and demonstrated an ability to pump at a rate of 40 gpm over a 24-hour period with negligible drawdown, which is far more capacity than the 10.6 gpm the Proposed Project would require for on-site irrigation. Based on the findings of the well capacity and sustainability test, this rate of pumping would have a highly localized radius of influence, if any, , and would be greatly overshadowed by the radius of influence associated with the agricultural and municipal supply wells in the surrounding vicinity. Therefore, given Napa County’s active management of the Subbasin under SGMA, available information, and the City’s implementation of a water neutral development policy, the Proposed Project’s contribution to a cumulative impact with regard to groundwater is not considerable resulting in a less-than-significant contribution.

Mitigation Measures
None required.

3.9.6 References
City of St. Helena. 1993. City of St. Helena General Plan. http://www.ci.st-helena.ca.us/ planning/page/1993-general-plan.

City of St. Helena. 2003. City of St. Helena Comprehensive Flood Protection Project Revised Draft Environmental Impact Report. Prepared by CDM in association with MBK, MOG, and Swanson Hydrology and Geomorphology. August 2003. State Clearinghouse No. 2002012078.

City of St. Helena. 2004. City of St. Helena Comprehensive Flood Protection Project Final Environmental Impact Report. Prepared by CDM in association with MBK, MOG, and Swanson Hydrology and Geomorphology. January 2004. State Clearinghouse No. 2002012078.

Agenda Item #6.2.

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City of St. Helena 2008. Final Plan to Minimize Impacts to Adjacent Landowners- City of St.

Helena Flood Protection and Flood Corridor Restoration Project. Accessed April 23, 2019. https://water.ca.gov/LegacyFiles/floodmgmt/fpo/sgb/ fpcp/prop84/comp_sol/2008_selections/alist_projects/st_helena/Final_StHelena_Plan_to _minimize_impacts.pdf.

City of St. Helena. 2012. City of St. Helena Flood Project, Office of Director of Public Works January 26, 2012 Presentation. Presented to Watershed Information Center & Conservancy of Napa County. Accessed April 23, 2019.
https://www.napawatersheds.org/managed_files/Document/8622/WICC-Presentation26JAN2012.pdf.

City of St. Helena. 2018. St. Helena General Plan Update 2040, Draft Environmental Impact Report. SCH# 2010042001. October 23, 2018.

City of St. Helena. 2019. City of St. Helena General Plan Update 2040. June 2019.

CVRWQCB (Central Valley RWQCB). 2016. 303(d) Impaired Water Bodies List. https://www.waterboards.ca.gov/rwqcb5/water_issues/tmdl/ impaired_waters_list/#intrpt2018.

DWR (Department of Water Resources). 1992. Well Completion Report No. 482209. Township & Range Section 08N05W30 Certified by Doshier & Gregson. Signed August 10, 1992.

DWR. 2019a. Sustainable Groundwater Management Act 2018 Basin Prioritization. https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/GroundwaterManagement/Basin-Prioritization/Files/2018-Sustainable-Groundwater-ManagementAct-Basin-Prioritization.pdf?la=en&hash=B9F946563AA3E6B338674951A7FF B0D80B037530.

DWR. 2019b. Well Completion Report Map Application and Data Download. T08SR06W25, T08SR06W36, T08SR05W30, and T08SR05W31. Accessed April 5, 2019. https://dwr.maps.arcgis.com/apps/webappviewer/index.html?id=181078580a214c0986e 2da28f8623b37.

DWR. 2021. SGMA Data Viewer. Accessed September 18, 2020 and confirmed on June 16, 2021. https://sgma.water.ca.gov/
webgis/?appid=SGMADataViewer.

Agenda Item #6.2.

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FEMA (Federal Emergency Management Agency). 2012. Flood Insurance Rate Map. Napa County, California and Unincorporated Areas. FIRM Panel No 06055C0264E. Accessed at FEMA Map Service Center. Letter of Map Revision (LOMR) 12-09-0871P, Effective 11/5/2012. https://msc.fema.gov/portal/home.

LSCE (Luhdorff and Scalmanini Consulting Engineers). 2016. Napa Valley Groundwater Sustainability – A Basin Analysis Report for the Napa Valley Subbasin. Alternative Groundwater Sustainability Plan (GSP) Submitted to DWR. Prepared for Napa County.

December 16, 2016.

LSCE. 2021. Napa County Groundwater Sustainability – Annual Report for Water Year 2020.

Prepared for Napa County. April 2021.

Max H. Yuan, Project Engineer, P.E., Engineering Management Branch, FEMA, Letter to The Honorable Del Britton, Mayor, City of St. Helena, November 30, 2007.

Mead & Hunt, MBK Engineers, and Kleinfleder, 2006. City of St. Helena Comprehensive Flood Protection Project Application for a Conditional Letter of Map Revision to the FIRMs for Napa County, California: Community No. 0602050275A City of St. Helena, California:

Community No. 06020800050.

Napa County. 1998. Department of Public Works, Flood and Water Resources. Measure A:

Napa Flood Protection and Watershed Improvement Expenditure Plan. Accessed April 23, 2019. https://www.countyofnapa.org/DocumentCenter/View/2553/Measure-APDF?bidId=.

Napa County. 2007. Napa County General Plan Update Draft Environmental Impact Report.

SCH# 2005102088. February 16, 2007.

Napa County. 2013. Napa County Operational Area Hazard Mitigation Plan. 2013 Update.

Executive Office, Emergency Services Division. https://www.countyofnapa.org/ DocumentCenter/View/779/Napa-Operational-Area-Hazard-Mitigation-Plan-2013- PDF?bidId=. 2013.

Napa County. 2019. Department of Public Works, Flood and Water Resources. The History of Floods. Accessed April 23, 2019. https://www.countyofnapa.org/ 1094/The-History-of-Floods.

Napa County FCWCD (Flood Control and Water Conservation District). 2019. Water Level Record for the Napa River near St. Helena, California (11456000). Napa Valley Regional Rainfall and Stream Monitoring System. https://napa.onerain.com/home.php.

Agenda Item #6.2.

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Napa Valley Registrar. 2019. https://napavalleyregister.com/news/local/flood-defenses-holdnapa-valley-in-good-shape-after-storm/article_093203c1-3806-55df-843a6cb7347ef28c.html.

O’Conner, Matthew. 2021. Well Capacity and Sustainability Assessment, Proposed Hunter Subdivision. September 9, 2021.

San Francisco Bay RWQCB (Regional Water Quality Control Board). 2017. San Francisco Bay Bain (Region 2) Water Quality Control Plan. Adopted in1995, amended through May 7, 2017. Accessed April 16, 2019. Website: www.waterboards.ca.gov/ sanfranciscobay/basin_planning.shtml.

SWRCB (State Water Resources Control Board). 2019. Final 2014/2016 California Integrated Report (Clean Water Act Section 303(d) List/305(b) Report). Accessed April 16, 2019. https://www.waterboards.ca.gov/water_issues/programs/tmdl/integrated2014_2016.shtm.

US Climate Data. 2019. Napa, California Monthly Averages. US Climate Data version 2.3 Webpage. Accessed April 10, 2019. https://www.usclimatedata.com/climate/napa/ california/united-states/usca2061.

USGS (U.S. Geological Survey). 2006. Storms and Flooding in California in December 2005 and January 2006 – A Preliminary Assessment. USGS Open File Report 2006–1182. 2006. https://pubs.usgs.gov/of/2006/1182/pdf/ofr2006-1182.pdf.

Western Regional Climate Center. 2016. Saint Helena, California (047643) Coop Station Monthly Climate Summary. Accessed May 2, 2019. https://wrcc.dri.edu/cgibin/cliMAIN.pl?ca7643.

Agenda Item #6.2.

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3.10 LAND USE

3.10.1 Introduction
This section describes existing and planned land uses within and adjacent to the proposed Hunter Subdivision Project (Proposed Project) site within the City of St. Helena (City), identifies land use designations, and zoning, and analyzes consistency of the Proposed Project with the City’s 1993 General Plan goals and policies and the City’s Municipal Code, Title 17 Zoning.

The City has since adopted an update to the 1993 General Plan; the 2019 General Plan (known as the “General Plan Update 2040,” a General Plan with a planning horizon of 2040) was adopted in May 2019. However, since the Proposed Project application was submitted in September 2010 and deemed complete by the City in 2011, this Environmental Impact Report (EIR) uses the 1993 General Plan as the applicable general plan for the purposes of evaluating consistency of the Proposed Project with the City’s General Plan policies in effect when the application was deemed complete by the City. Nonetheless, this EIR also evaluates consistency with the City’s adopted 2019 General Plan for informational and consistency purposes.

California Environmental Quality Act (CEQA) Guidelines Section 15125(d) provides that the environmental setting of an EIR must discuss “any inconsistencies between the proposed project and applicable general plans and regional plans.” Potential inconsistencies between the Proposed Project and the City’s 1993 General Plan, and the Zoning Ordinance are discussed in this section in addition to a review of the City’s 2019 General Plan. Technical sections included in this Draft EIR also evaluate and analyze any potential physical/environmental effects and potential incompatibilities with the 1993 General Plan that may be considered in the determination of physical environmental impacts.

Comments received in response to the Notice of Preparation related to land use included concerns about consistency with the underlying land use designation and zoning, and potential conflicts with the City’s 1993 General Plan. All of these issues are addressed in this section. A copy of the Notice of Preparation and comments received is included in Appendix A.

Information for this section was primarily obtained from the City of St. Helena 1993 General Plan (City of St. Helena 1993), City of St. Helena 2019 General Plan (City of St. Helena 2019), City of St. Helena Municipal Code, and other miscellaneous Proposed Project information.

3.10.2 Environmental Setting
The following provides an overview of the existing land use designation, zoning and land uses on the Project site as well as the surrounding land use designations and zoning.

Agenda Item #6.2.

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Existing Site
The Project site (Assessor’s Parcel Number is 009-030-057) is located in the northeast portion of the City, at the eastern terminus of Adams Street and the west/north1terminus of Starr Avenue, three blocks east of downtown and State Route 29, and generally south/west of the Napa River. The Project site has historically been used for agriculture and contained an orchard that was removed in the 1960s. In the early 1970s a small vineyard was planted on approximately 7-acres of the Project site. In the mid-2000s the site was altered by the addition of fill material primarily associated with the construction of the St. Helena Comprehensive Flood Protection Project (Flood Protection Project) along the Napa River, located to the north and northeast of the Project site.

The Project site is presently undeveloped with the exception of a small vineyard under active cultivation located in the southwestern portion of the site, near the terminus of both Adams Street and Starr Avenue. The site is generally level and does not contain any streams or waterways. Trees are located along the edge of the southern/southeastern boundary of the site, including parallel to the Vineyard Valley Mobile Home Park. Based on the Proposed Project’s grading plan, the elevation across the Proposed Project’s development footprint ranges from approximately 230 feet above mean sea level on its southern edge to approximately 212 feet above mean sea level on its northern edge. The portion of the site planned for the extension of Adams Street ranges from 243 feet to 230 feet above mean sea level. An existing well is located near the southeastern edge of the Project site.

Surrounding Land Uses
Adjacent land uses include single-family and multi-family residential development to the south and southeast, including the Vineyard Valley Mobile Home Park, Hunt’s Grove Apartments, and single-family residences along Starr Avenue (see Figure 2-3 in Chapter 2, Project Description).

Office uses are located immediately adjacent to the site’s westernmost edge at the terminus of Adams Street. Single-family residences along Monte Vista Avenue and Hunt Avenue back up to the site. Undeveloped land currently under cultivation or fallow is located to the north and northwest. A single-family residence along with an accessory dwelling unit and barn is currently under construction just north/west of the site. A gravel maintenance road/public trail borders the site along the north/northwest and a city storm water detention basin borders the site to the south/southeast. A drainage ditch is located along the southwestern edge of the property. Starr Avenue and Adams Street essentially stub into the Project site. 1 The site is oriented on an axis that runs generally on a diagonal from southwest to northeast. Directions in relation to the site are therefore in many cases not directly “north” or “’west” are shown as a combination of directions.

Agenda Item #6.2.

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The open space areas located north and east of the site are part of the City’s Flood Protection Project. The Napa River is located approximately 540 feet north and northeast of the Project site.

Land uses surrounding the Project site are currently designated High Density Residential (HDR) and Medium Density Residential (MDR) adjacent to the south and southeast; Open Space to the north and along the western Proposed Project boundary, and Agriculture farther west in the City’s 2019 General Plan. In the 1993 General Plan, the Open Space parcel to the north and west of the Project site was designated as MDR rather than Open Space.

City of St. Helena 1975 General Plan Land Use Designation The project site was designated for high density residential development in the 1975 St. Helena General Plan. Densities envisioned in the 1975 General Plan were 4-6 units per acre for single family homes and up to 16 units per acre for multi-family dwellings.

That land use policy was revised with the adoption of the updated 1993 General Plan (discussed below).

City of St. Helena 1993 General Plan Land Use Designations The Project site is designated as MDR in the City’s 1993 General Plan. According to the 1993 General Plan, “[t]he MDR designation provides for single-family detached and attached homes, secondary residential units, public and semi-public uses, and similar and compatible uses.

Residential densities shall be in the range of 5.1 to 12.0 dwelling units per gross acre (du/acre).

The MDR designation is the predominant residential designation, occurring throughout large areas of the City. The wide distribution of this designation is intended to maintain a development pattern in newly developing areas that is consistent with historic development patterns” (City of St. Helena 1993).

City of St. Helena 2019 General Plan (“General Plan Update 2040”) As previously mentioned, the City adopted the 2019 General Plan, known as the “General Plan Update 2040,” in May 2019. However, since the Proposed Project application was submitted in September 2010 and deemed complete by the City in 2011, this EIR uses the 1993 General Plan as the applicable general plan for the purposes of evaluating the Proposed Project. For informational purposes, the City’s 2019 General Plan designates the Project site for MDR, the same as the 1993 General Plan (City of St. Helena 2019, Figure 2.1). However, the allowable density is up to 16.0 dwelling units per acre.

Agenda Item #6.2.

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Existing Zoning
The City of St. Helena’s Zoning Code (Title 17) specifies building setback, building height, building density, and site coverage to ensure that the public’s health, welfare, and safety would be protected and that development occurs in a planned, logical fashion. The Project site is currently zoned Medium Density Residential (MR), which allows a residential density of between

5.1 to 16.0 dwelling units per acre. The MR district is consistent with the MDR General Plan designation. The MR district provides for single-family detached homes, accessory dwelling units, limited agricultural uses and compatible uses, as well as attached duplex and triplex units, condominiums, and townhouses, and similar uses with a use permit.

The City’s General Plan Housing Element Update 2015–2023 was revised and last updated in May 2015. The City’s 2015-2023 Housing Element identifies the site as vacant and underutilized (City of St. Helena 2015b, p.133, Table 43).

3.10.3 Regulatory Setting
There are no federal or state land use requirements applicable to the Proposed Project.

Regional Regulations
Plan Bay Area 2040
Plan Bay Area 2040 (Plan), adopted in 2017, is a state-mandated, integrated long-range transportation and land use plan. The region adopted its previous plan — Plan Bay Area — in July 2013. As the Bay Area’s first regional transportation plan to include a Sustainable Communities Strategy (SCS) as required by Senate Bill (SB) 375, the original Plan Bay Area (2013) charted a course for reducing per-capita greenhouse gas emissions through the promotion of more compact, mixed-use residential and commercial neighborhoods near transit.

In the Bay Area, the Metropolitan Transportation Commission and the Association of Bay Area Governments (ABAG) are jointly responsible for developing and adopting a SCS that integrates transportation, land use and housing to meet greenhouse gas reduction targets set by the California Air Resources Board. Plan Bay Area 2040 projects household and employment growth in the Bay Area over the next 24 years, provides a roadmap for accommodating expected growth, and connects it all to a transportation investment strategy that strives to move the Bay Area toward key regional goals for the environment, economy and social equity.

SB 375 was adopted with the goal of reducing greenhouse gas emissions from cars and light trucks. SB 375 will make it easier for communities to build housing and provide transportation choices. The SCS is a plan to meet the region’s greenhouse gas emissions reduction target, while taking into account regional housing needs, transportation demands, and protection of Agenda Item #6.2.

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resource and farm lands based on the best forecast of likely land use patterns provided in coordination with ABAG’s partner agencies.

Local Regulations
City of St. Helena 1993 General Plan
As noted in the General Plan, “growth continues to be one of, if not the primary issue facing St.

Helena according to input from the community. Since the early 1970s when the City experienced a dramatic increase in growth pressures, the community has strongly supported a policy of deliberate slow growth in order to protect the fragile charm and beauty of the City, to ensure that natural resources such as water supply and prime agricultural land are not lost or overused, and to ensure that adequate public services such as schools and sewers can be provided. In addition to regulating the rate of growth, the City will also control where growth can occur by establishing an Urban Service Area.” To address the desire to manage growth the City developed an Urban Service Area, which discourages urban sprawl by containing urban development within the designated Urban Service Area. The Urban Service Area is surrounded by agriculturally designated land and includes 663 acres designated for residential uses to accommodate projected growth, while maintaining a rational and compact development pattern at buildout (City of St. Helena 1993). The Project site is within the Urban Limit Line, which runs along the westerly edge of the Project site, separating it from the agricultural lands to the west and north.

The following goals and policies from the 1993 General Plan applicable to the Proposed Project are listed below. A consistency analysis for all the policies listed below is included in the impact section.

Growth Management
Policy 2.6.1: New development should be required to occur in a logical and orderly manner within well-defined boundaries, and be consistent with the ability to provide urban services.

Policy 2.6.2: Urban development shall be allowed to occur only within the Urban Service Area during the time frame of the General Plan.

Policy 2.6.3: Urban services such as sewer, water, and storm drainage will only be extended to development within the Urban Service Area. Exceptions will be permitted when undue hardship can be demonstrated, and proposed improvements are not found to be growth inducing.

Agenda Item #6.2.