St. Helena City Council
June 26, 2023

2 – PROJECT DESCRIPTION
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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 2040 General Plan Update. Adopted June 2019.

RSA. 2020. Approximate Raw Earthwork Quantities Based on Tentative Map. February 6, 2020.

Agenda Item #6.2.

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CHAPTER 3.0

INTRODUCTION TO THE ANALYSIS

3.0.1 SCOPE AND FORMAT OF THE EIR
This chapter of the Draft Environmental Impact Report (EIR) discusses the environmental and regulatory setting, impacts, and mitigation measures from the proposed Hunter Subdivision Project (Proposed Project) for each of the following technical issue areas (Sections 3.1 through 3.15):

3.1 Aesthetics

3.2 Agricultural Resources

3.3 Air Quality

3.4 Biological Resources

3.5 Cultural, Paleontological and Tribal Cultural Resources

3.6 Geology and Soils

3.7 Greenhouse Gas Emissions

3.8 Hazards and Hazardous Materials

3.9 Hydrology, Drainage, and Water Quality

3.10 Land Use

3.11 Noise and Vibration

3.12 Public Services and Recreation

3.13 Public Utilities

3.14 Transportation and Circulation

3.15 Energy
It is important to note impacts of the environment on a project or plan (as opposed to impacts of a project or plan on the environment) are beyond the scope of required California Environmental Quality Act (CEQA) review. “[T]he purpose of an EIR is to identify the significant effects of a project on the environment, not the significant effects of the environment on the project” (Ballona Wetlands Land Trust v. City of Los Angeles (2011) 201 Cal.App.4th 455, 473 and California Building Industry Association v. Bay area Air Quality Management District (2015) Cal.App 4th).

The Residential Growth Management System Ordinance (Chapter 17.152) of the City of St.

Helena (City) regulates the residential growth within the City to approximately 2% per year. It limits the number of building permits to nine per year for market rate housing and caps the number of dwelling units to approximately 2,800, not including regulated affordable units, guest cottages, or accessory dwelling units. Since the City adopted its Residential Growth Management System in 1979 and last updated in 2002, the state passed Senate Bill 330 (see Government Code Section 66300). Section 66300 includes language that prevents cities from “establishing or implementing any provision that . . . [a]cts as a cap on the number of housing Agenda Item #6.2.

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units that can be approved or constructed either annually or for some other period” (Section 66300(b)(1)(D)(ii) [emphasis added]).

Under current state law the City can no longer implement a restriction on the number of residential units that can be constructed. There is an exception for growth control measures of this type approved by the voters prior to Jan. 1, 2005, if the affected city is in a “predominantly agricultural county,” which is defined as a county that has more than 550,000 acres of agricultural land, and at least half the county area is agricultural land. Napa County does not meet the definition of an agricultural county; therefore, this exception is not applicable to the City.

Technical Studies
A number of technical studies were prepared as part of this Draft EIR and are included in the technical appendices. Studies prepared include the results of a Land Evaluation and Site Assessment to assess agricultural land (Appendix B), Biological Resource Assessment and Wetland Delineation (Appendix D), Cultural Resources Report (Appendix E), Geotechnical Reports (Appendix F), a Phase I Environmental Site Assessment (Appendix G), Hydrology Report (Appendix H), Preliminary Water Calculations (Appendix J), and a Traffic Impact Assessment (Appendix K).

Environmental Setting
According to Section 15125 subdivision (a) of the CEQA Guidelines, an EIR must include a description of the existing physical environmental condition in the vicinity of the project as they exist at the time when the Notice of Preparation (NOP) is published. This “environmental setting” will normally constitute the “baseline condition” against which project-related impacts are compared.

Therefore, the baseline conditions for this EIR, unless noted otherwise, are based on conditions that existed in March 2018, when the NOP was published. The CEQA Guidelines recognize that the data for establishing an environmental baseline cannot be rigid. Because physical environmental conditions may vary over a range of time, the use of environmental baselines that differ from the date of the NOP is reasonable and appropriate in certain circumstances when doing so results in a more accurate or conservative environmental analysis.

For analytical purposes, impacts associated with implementation of the Proposed Project are compared against two different baselines: first, Proposed Project–specific effects are assessed against existing conditions at the time the NOP was first published; and second, cumulative effects are assessed against future, or “cumulative,” conditions, generally defined as buildout of the City of St. Helena’s 1993 General Plan because this General Plan was in effect when the Proposed Project application was deemed complete in September 2011. The City adopted the 2040 General Plan Update 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 Agenda Item #6.2.

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General Plan as the applicable general plan for the purposes of evaluating the Proposed Project.

Nonetheless, this EIR will also evaluate consistency with the General Plan Update 2040 for informational purposes and the cumulative analysis will note any changes, if relevant between buildout assumptions under the 1993 General Plan as compared to the 2040 General Plan.

Existing conditions and the cumulative baseline can differ by issue area. In some instances the cumulative analysis information from the City’s General Plan Update 2040 Draft EIR released in in October 2018 is referenced because this was the most current information regarding future cumulative development at the time of writing the technical section. Each technical section defines the existing conditions and cumulative baseline for the impacts being analyzed.

Project Analysis Assumptions
The Proposed Project is requesting approval of Tentative Subdivision map that includes 51 singlefamily lots, a lot designated for 25 attached multi-family units, and 11 accessory dwelling units.

The City’s Zoning Ordinance (Municipal Code Section 17.116.030) and state law provides for the construction of an accessory dwelling unit on any lot which is zoned for residential use and has an existing single-family residence. Such units may be rented (for a period of not less than 30 days) but may not be sold separately from the main residence. The Proposed Project applicant has proposed construction of 11 accessory dwelling units as part of the Proposed Project.

The Proposed Project application does not include a formal phasing plan. Therefore, for the purposes of this EIR buildout of the Project would occur based on market conditions and the timeliness of obtaining building permits. Therefore, it is assumed that the Project could take anywhere from 6 years or longer for full buildout, based on market and growth management factors. Most environmental impacts assessed in this EIR are analyzed in terms of the postProject condition and are not substantially affected by the construction schedule. Air Quality and Greenhouse Gas Emissions for construction are affected by the length of construction.

Therefore, emissions associated with a six-year buildout are conservatively assumed and provided in the air quality and greenhouse gases analysis (Sections 3.3 and 3.7).

In determining the level of significance of environmental impacts associated with the Proposed Project, the analysis in this Draft EIR assumes that the Proposed Project would comply with relevant federal and state laws and regulations, City General Plan policies, ordinances, and other adopted City documents, unless otherwise noted. Therefore, such mandatory policies, ordinances, and standards are not identified as mitigation measures, but rather are discussed as part of the “Regulatory Setting” governing the Proposed Project and compliance with these requirements often mitigate potential impacts.

Agenda Item #6.2.

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Section Format
Each technical section in Chapter 3 begins with an introduction that explains the issues to be evaluated, provides a general summary of comments received in response to the NOP, and identifies the primary sources reviewed to prepare the analysis. The introduction is followed by a description of the Proposed Project’s environmental setting and regulatory setting as it pertains to a particular issue.

The environmental setting establishes the baseline for that particular issue area and includes information relevant to the analysis of potential impacts. The regulatory setting provides a summary of applicable federal, state, and local regulations, plans, policies, and laws that are relevant to each issue area. The regulatory setting description in each section is followed by a discussion of the methods of analysis and the thresholds of significance used to evaluate Proposed Project–specific impacts. The project-specific impacts discussion is followed by an analysis of the cumulative impacts of the Proposed Project. This section addresses what the Proposed Project’s incremental contribution to any existing cumulatively significant impacts would be and identifies mitigation measures, if required. The impact statement is prefaced by a number for ease of identification. An explanation of each impact and an analysis of its significance follow each impact statement. All mitigation measures are identified immediately following each impact discussion. The degree to which the identified mitigation measure(s) would reduce the impact is also described. Compliance with applicable laws, policies, and City regulations is assumed and will be identified in the impact analysis. In many cases, compliance with applicable laws, policies, or regulations would reduce the significance of a potential impact; and thus, would not be identified as a separate mitigation measure.

An example of an impact statement is shown below.

3.1-1: Would the Proposed Project have a substantial adverse effect on a scenic vista? This impact would be less than significant. (The significance finding prior to mitigation is included in each impact statement).

A discussion of potential impacts of the Proposed Project is presented in paragraph form. The Proposed Project–specific impacts associated with construction and operation of the Proposed Project are evaluated and compared to the threshold of significance for the particular impact.

The analysis discusses the applicable local, state, and federal laws and regulations along with applicable general plan goals and policies that would reduce impacts, and assumes that the Proposed Project would comply with applicable laws, ordinances, goals, policies and regulations, and that the Proposed Project applicant would obtain all necessary permits and comply with all required conditions of those permits. In many instances, the actions that are necessary to reduce a Proposed Project impact are already required by existing laws or Agenda Item #6.2.

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requirements. The impact analysis concludes with a determination of the impact’s significance in bold type (e.g., significant impact, significant and unavoidable impact, potentially significant impact, less-than-significant impact, or no impact).

Mitigation Measures
A discussion of the applicable mitigation measures identified to reduce the significance of an impact immediately follows the impact analysis.

This section includes a statement indicating whether the mitigation measure would reduce the impact to a less-than-significant level or if the impact remains significant and unavoidable due to the absence of any available mitigation that could reduce the impact below the applicable threshold. A discussion of how the mitigation would reduce the impact is included before the mitigation measure.

Mitigation measures, if applicable, are numbered and presented in the following format.

AES-1 Statement of what, if any, mitigation measures are required.

Note that CEQA Guidelines, Section 15370, defines mitigation as follows:
• Avoiding the impact altogether by not taking a certain action or parts of an action • Minimizing impacts by limiting the degree of magnitude of the action and its implementation • Rectifying the impact by repairing, rehabilitating, or restoring the affected environment • Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action
• Compensating for the impact by replacing or providing substitute resources or environments In addition, provided there is a “reasonable plan for mitigation” and contributions are “sufficiently tied to the actual mitigation” of the project’s impacts, a commitment to contribute a fair share to such a program discharges an agency’s mitigation duty under CEQA (Save Our Peninsula Com. v. Monterey County Bd. of Supervisors 2001) 87 Cal.App.4th 99, 141); see also CEQA Guidelines, Section 15130(a)(3) [recognizing that a project’s contribution to a cumulative impact may be less than cumulatively considerable where “the project is required to implement or fund its fair share of a mitigation measure or measures designed to alleviate the cumulative impact”]; see also Anderson First Coalition v. City of Anderson (2005) 130 Cal.App.4th 1173).

Agenda Item #6.2.

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Cumulative Impacts
An analysis of cumulative impacts follows the evaluation of Proposed Project impacts under existing conditions in each section in Chapter 3. As defined in CEQA Guidelines, Section 15355, cumulative impacts refer to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts. The cumulative impact from several projects is the change in the environment which results from the incremental impact of the Proposed Project, together with other past, present, and reasonably foreseeable projects causing related impacts.

An introductory statement that defines the cumulative analysis methodology and the cumulative context being analyzed for the respective sections (e.g., buildout of the City’s General Plan, development within the Bay Area Air Basin) is included under the “Cumulative Analysis” discussion.

In some instances, a Proposed Project–specific impact may be considered less than significant but would be considered potentially cumulatively significant in combination with other development within the surrounding area. Or, in some instances, a potentially significant impact could result on a project level but would not result in a cumulatively considerable impact. The cumulative impacts analysis is presented in the same format as the impacts section, shown above.

3.0.2 TERMINOLOGY USED IN THIS EIR
This Draft EIR uses the following terminology to describe environmental effects of the Proposed Project:
• Thresholds of Significance: A set of criteria used by the lead agency to determine at what level or “threshold” an impact would be considered significant. Standards of significance used in this Draft EIR include those set forth in CEQA Guidelines Section 15065 (Mandatory Findings of Significance) and those derived from questions set forth in the most recent update to Appendix G to the CEQA Guidelines; criteria based on regulatory standards of local, state, and federal agencies; and criteria based on goals and policies identified in the City of St. Helena 1993 General Plan. In fashioning criteria based on these sources, City staff has also relied on its own professional judgment and experience in some instances. In determining the level of significance, the analysis assumes that the Proposed Project would comply with relevant federal, state, and local regulations and ordinances.
• Less-than-Significant Impact: A project impact is considered less than significant when it does not reach the standard of significance, indicating that there would be no substantial change in the environment. No mitigation is required for less-than-significant impacts. • Potentially Significant Impact: A potentially significant impact is an environmental effect that could cause a substantial adverse change in the environment; however, Agenda Item #6.2.

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additional information is needed regarding the extent of the impact to make the determination of significance. For CEQA purposes, a potentially significant impact is treated as if it were a significant impact.
• Significant and Unavoidable Impact: A significant and unavoidable impact is an environmental impact that cannot be mitigated to a less-than-significant level. There are no feasible mitigation measures available to reduce the significance of the impact; therefore, the impact is considered significant and unavoidable. • Cumulative Impact: According to CEQA, “cumulative impacts refer to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts” (CEQA Guidelines, Section 15355). CEQA requires that cumulative impacts be discussed when the “project’s incremental effect is cumulatively considerable” (CEQA Guidelines, Section 15130[a]).

Agenda Item #6.2.

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3.1 – AESTHETICS / VISUAL RESOURCES
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3.1 AESTHETICS / VISUAL RESOURCES

3.1.1 Introduction
This section describes the aesthetics and visual resources present in the Project area and discusses applicable federal, state, and local regulations pertaining to protection of visual resources. This section evaluates the potential effects on visual resources associated with development of the proposed Hunter Subdivision Project (Proposed Project).

Comments received in response to the Notice of Preparation (NOP) included concerns regarding the proposed design of the residential units, impacts to surrounding viewsheds and scenic vistas, impacts to landscape buffers, and light spillover impacts to the night sky. All of the concerns raised are addressed in this section. A copy of the NOP and comments received is provided in Appendix A. The Proposed Project applicant is only requesting approval of a Tentative Subdivision Map at this time; therefore, no building design details have been provided and an analysis of project design features is not included. As noted in Chapter 2, Project Description, if the Proposed Project is approved the City would require additional subsequent discretionary approvals, including Design Review.

Information contained in this section is based on site plans, a field survey, and City planning documents (including the 1993 General Plan and the 2019 General Plan). Other sources consulted are listed in Section 3.1.6, References.

3.1.2 Environmental Setting
This section describes the existing setting in the Project area and identifies the resources that could be affected by implementation of the Proposed Project.

Regional Setting
The City of St. Helena (City) is situated within the Napa Valley floor, bounded by the Mayacamas Mountain Range on the western and northern sides and the Howell Mountains on the eastern side. The region is located within the Napa Valley American Viticultural Area and is famous for the widespread vineyards that characterize the valley. The Napa River bisects the valley and flows through the eastern portion of the City. The City’s terrain ranges from flat agricultural areas to gently rolling foothills. The primary regional access route to the City is State Route (SR) 29, a north-south corridor that passes through the Napa Valley. The City has a rural aesthetic characterized by open space, agricultural lands, wineries, wooded hillsides, and stream corridors.

The City has views of many hills and mountainsides, including Mount St. Helena, a peak of the Mayacamas Mountain Range located in Robert Louis Stevenson State Park.

Agenda Item #6.2.

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Development within the City is relatively compact, with the majority of commercial development and wineries situated along the SR 29 corridor, and residential development surrounding the Central Business District along SR 29 between Sulphur Springs Creek and Pine Street. Residential development within the City is primarily located west of Main Street and north of Sulphur Springs Creek. Flat agricultural lands surround the central developed area of the City, while limited rural residential development occupies wooded hillsides to the east and west of the City.

Project Site
The 16.9-acre Project site is characterized by row vineyards in the western portion and undeveloped land consisting of annual grasses in the eastern portion of the site (see Figure 2-2 in Chapter 2, Project Description). Approximately 40% of the Project site currently supports a small vineyard. Based on the Proposed Project’s grading plan, the elevation of the site ranges from approximately 230 feet above mean sea level (amsl) on its southern edge to approximately 212 amsl on its northern edge. Adams Street terminates at the western boundary of the site, three blocks east of downtown and SR 29. Office uses, including an off-white two-story building with large reflective windows, are located immediately adjacent to the site’s most western edge at the terminus of Adams Street.

Vineyards are located to the north and northeast of the Project site, with a small number of large 1- and 2-story single-family residences located north of the Project site. The George and Elsie Wood Public Library, a one-story tan-colored building with a small patch of vineyards, is located approximately 0.1 of a mile northwest of the Project site. A gravel maintenance road/public trail lined with a simple wood-post and barbed wire fence abuts the northern boundary of the Project site. One and two-story single-family and multi-family residential development is located to the south of the site. Residences to the south of the Project site include a mix of neutral-colored buildings in a variety of styles with mature trees and shrubs. Single-family residences front Grove Court and Monte Vista Avenue to the east and some include backyards while others do not. The Vineyard Valley Mobile Home Park and multi-family housing in the Hunts Grove Apartments complex are located south and east of the Project site. Multi-family residences are primarily located along Hunt Avenue and either front the street or face the Project site. These residences are separated from the Project site by either a low stone wall or a taller wood and wire fence. Residences along Del Campo Court and Del Rio Court are neutral-colored singlefamily residences that face the Project site.

The Napa River is located approximately 0.1 miles north and northeast of the Project site.

The Project site was designated as high-density housing in the 1975 St. Helena General Plan as Medium Density Residential (MDR) in the City’s 1993 General Plan (City of St. Helena 1993), and as MDR in the 2019 General Plan. Land designated as MDR typically is for residential Agenda Item #6.2.

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purposes, and provides for single-family detached and attached homes, secondary residential units, public and semi-public uses, and similar and compatible uses. The zoning designation for the Project site is also Medium Density Residential (MR) (City of St. Helena 2018).

Viewpoints
A viewshed is an analytical tool used to aid in the identification of views that could be affected by a project. The viewshed is defined as the surrounding geographic area from which a project is likely to be seen. Locations of key viewpoints that depict the viewshed visible in the Proposed Project vicinity are depicted in Figure 3.1-1 and photos from these representative viewpoints are shown in Figures 3.1-2 through 3.1-5.

Views from the Project Site
Long-range views from the Project site include views of surrounding wooded hillsides with tall trees. Surrounding hillsides including the Howell and Mayacamas mountains are visible from the Project site looking west and northwest due to the flat topography and lack of tall intervening structures. Short to mid-range views to the north of the Project site consist of the gravel maintenance road/public trail that borders the site, with vineyards visible beyond. Buildings associated with vineyards to the north of the site are also visible. Views to the south/east include views of single-family residences along Grove Court and Monte Vista Avenue, along with grassland vegetation and native plants and shrubs associated with undeveloped areas to the east of the gravel maintenance road/public trail. Adams Street is visible to the west of the Project site, along with a two-story off-white office building and the George and Elsie Wood Public Library, which are located on Adams Street. Short-range views of single-family and multifamily residences with a mix of mature trees are visible looking south/east from the Project site.

Views of the Project Site
The Project site is visible from residences to the south, as well as from the intersection of Hunt Avenue and Starr Avenue, where there is a clearing in the dense vegetation that borders the site to the south and southwest (Figure 3.1-2). From this intersection, the on-site vineyard and annual grasses on the site are visible in the foreground, with the Howell Mountains visible in the background.

The Project site is visible from the eastern terminus of Adams Street, which is adjacent to the western portion of the site (Figure 3.1-3). Views from this location are of the on-site vineyard, as well as vineyards on surrounding properties. Surrounding wooded hillsides can be clearly seen in the background from this location. Large, mature trees are also visible at the southern boundary of the site. From the gravel maintenance road/public trail to the north and northwest of the Project site there are uninterrupted views of the vineyard and grass areas on the Project site Agenda Item #6.2.

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in the foreground with views of multi-story residential units and tall evergreen trees in the background (Figure 3.1-4). Surrounding mountain ranges are largely blocked from view from the gravel maintenance road/public trail looking south towards the Project site. Views of the Howell Mountains can be seen looking to the east from the trail (Figure 3.1-3), and the Mayacamas Mountains can be seen looking towards the west from the trail (Figure 3.1-5). Residences along Del Rio Court to the southeast of the Project site experience views of grass and vegetation on the site in the foreground, and views of the Howell Mountains in the background (Figure 3.1-5).

Adjacent residences are considered to have high sensitivity – both their expectations of visual quality and their time of exposure is typically greater than motorists traveling on adjacent roadways that comprise the other viewer groups.

The Project site is not visible from major transportation corridors such as SR 29/Main Street or the Silverado Trail, which is located approximately 0.2 miles east of the Project site. The Project site is also not visible from public parks in the vicinity of the site.

Scenic Resources
The California Department of Transportation designates SR 29 as an eligible state scenic highway (Caltrans 2018). The Project site is located approximately 0.2 miles east of SR 29.

However, it is not visible from the highway due to intervening trees, buildings and structures.

While there are many scenic resources and vistas within the City, there are no specific scenic resources or vistas designated for protection in the City’s 1993 General Plan or the 2019 General Plan. No other scenic viewsheds or scenic highways are identified in the Project vicinity. No rock outcroppings or other significant natural or historical features exist on the site.

Light and Glare
Nighttime lighting is necessary to provide and maintain a safe and secure environment. Light that falls beyond the intended area of illumination is referred to as “light trespass.” Types of light trespass include spillover light and glare. Spillover light, which is light that illuminates surfaces beyond the intended area, is typically caused by artificial lighting sources, such as from building security lighting, signs, parking lot lights, roadway lights, and stadium lights on playing fields.

Spillover light can adversely affect light-sensitive uses (i.e., adjacent residences), by creating unwanted illumination. Because light dissipates as it moves farther from its source, the intensity of the lighting source is often increased to compensate for dissipating light, which can increase the amount of light that illuminates adjacent uses. The type of light fixture determines the extent to which light will spill over onto adjacent properties and/or be visible from far away. Modern, energy-efficient fixtures that face downward, such as cutoff-type fixtures and shielded light fixtures, are less obtrusive than light fixtures that have been used in the past.

Agenda Item #6.2.

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Existing Views
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Existing Views
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Existing Views
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View 5: View from the existing gravel maintenance road/public trail looking south View 6: Views of on-site vineyards from gravel maintenance road/public trail Agenda Item #6.2.

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Existing Views
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View 7: View from the existing gravel maintenance road/public trail looking west View 8: View from Del Rio Court looking west
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The second type of light trespass is glare, which results when a light source in the field of vision is brighter than the eye can comfortably accept. Glare can result from sunlight or from artificial light reflecting off building exteriors, such as glass windows, metal roofs or other highly reflective surface materials. Squinting or turning away from a light source is an indication of glare. Cutofftype light fixtures minimize glare because they emit relatively low-intensity light at these angles.

Glare resulting from sunlight reflecting off building exteriors can be reduced with design features that use low-reflective glass and exterior materials and colors that absorb, rather than reflect, light.

As the Project site is undeveloped, it does not contain existing light or glare sources. Existing light sources in the vicinity of the site include internal and external lighting from residences to the south, west and east of the Project site, vehicle headlights along adjacent roadways and buildings to the north of the site. Streetlights also line Adams Street to the west and Starr Avenue to the south at regular intervals up until the Proposed Project boundary.

3.1.3 Regulatory Setting
Federal Regulations
There are no federal regulations pertaining to visual resources that would apply to the Proposed Project.

State Regulations
The following state regulations would apply to the Proposed Project.

California Scenic Highway Program
California’s Scenic Highway Program was created by the Legislature in 1963 to preserve and protect scenic highway corridors from change which would diminish the aesthetic value of lands adjacent to highways. The state laws governing the Scenic Highway Program are found in the Streets and Highways Code, Section 260 et seq. The State Scenic Highway System includes a list of highways that are either eligible for designation as scenic highways or have been so designated. County roads can also become part of the Scenic Highway System. To receive official designation, the county must follow the same process required for official designation of State Scenic Highways.

SR 29 throughout Napa County is eligible for designation as a state scenic highway. Although SR 29 is located approximately 0.2 miles from the Project site, the site is not visible from the highway due to intervening buildings and structures. There are no other designated or eligible highways within the Project vicinity (Caltrans 2018).

Agenda Item #6.2.

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Local Regulations
The following local land use policies would apply to the Proposed Project.

City of St. Helena 1993 General Plan
The Land Use and Growth Management Element, Community Design Element and Open Space Element of the St. Helena 1993 General Plan provides guiding and implementing policies regarding visual resources. The City’s General Plan states, “The “planned unit development” approach provides developers with greater design flexibility while ensuring the City adequate design review. The intent is to create developments that complement existing community character. The City will favor planned unit developments that provide generous amounts of open space, covered parking, the separation of pedestrian and vehicle traffic, and on larger tracts, a variety of housing types: single-family detached, duplex, and multi-family dwellings, in one and two-story structures” (City of St. Helena 1993).

Land Use and Growth
Policy 2.6.15: Encourage new residential development in all density ranges that is consistent with scale and character of the older residential districts of the City, particularly the neighborhoods west of Main Street.

Policy 2.6.17: Minimize situations where new residential development will block public view of surrounding vineyards.

Policy 2.6.19: Permit higher density housing in single family neighborhoods as long as the development character of the single family area is maintained (i.e., lot widths, orientation to street, building heights, etc.).

Policy 2.6.20: Encourage the subdivision and development of larger parcels (3 acres or more) as “planned unit developments” to ensure a more comprehensive and creative approach to planning the development as a single unit.

Community Design
Policy 4.3.4: Strengthen community identity by appropriate building design, size, and site landscaping.

Policy 4.3.5: Require future residential development to conform to the pattern and density of older, neighboring areas of town in order to complement existing town character and ensure that densities are high enough to protect against unnecessary incursion into vineyard agricultural areas.

Agenda Item #6.2.

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Policy 4.3.23: Set residential densities throughout St. Helena at levels that will ensure that minimum encroachment on productive vineyard land or open space will occur during the life of the plan.

Policy 4.3.24: Encourage higher density residential development near the commercial core to provide convenient pedestrian access to shopping and services.

Ensure that higher density projects are similar in design and scale to adjacent single family neighborhoods.

Policy 4.3.25: Within the primary urban area of St. Helena, encourage variety in housing types and density consistent with those found in the older neighborhoods of town.

Encourage varying lot widths and configuration, but limit the allowable building envelope by parcel size to avoid overbuilt conditions.

Policy 4.3.26: Encourage residential building siting and design that is similar to that found in the older neighborhoods in town. In these areas consistent setbacks, porches and generously landscaped front yards add to community enjoyment by all. Restrict location of driveways and garages to minimize their visual impact on the street.

Policy 4.3.27: Encourage large specimen street trees and generous landscaping to shade homes and the street and to link various neighborhoods.

Policy 4.3.28: Limit residential development that backs up to vineyards and thereby blocks views of those vineyards by passersby.

Policy 4.4.2: When reviewing development proposals in areas not already served by a system of streets, City staff shall ensure that proposed development is sited in such a manner that it will not obstruct the logical extension of existing streets and infrastructure, or the expansion of the City's grid-like pattern of streets into newly developing areas. As with existing street patterns, new extensions of the city grid need not be rigid in their dimensions and layout, but should be evaluated on their contribution to the formation of a logical, interconnected system of streets that facilitates the safe and efficient flow of pedestrian, bicycle, and vehicular traffic, and establishes an attractive neighborhood environment. Staff can consider variations to the logical extension of existing streets if the project proponent can demonstrate that safety, aesthetics, topography, or other factors make such an extension ineffective or undesirable, or that such an extension would cause the landowner undue hardship.

Street widths should be the minimum adequate for two-way traffic and parking.

Narrower street widths as found in the older parts of St. Helena contribute to a more intimate small town scale and discourage speeding.

Agenda Item #6.2.

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September 2021 3.1-18
Policy 4.4.3: Driveways and garages should be as unobtrusive as possible, with garages preferably located at the rear of the lot.

Policy 4.4.4: Where streets are at the edge of the community, adjacent to vineyards, development should only occur on one side, leaving open views to the agricultural lands and hillsides.

Policy 4.5.1: The sense of a strong connection to the surrounding agricultural open space and hillsides must be preserved in the future. Views of vineyard, hillsides, creeks and major landscape features should be maintained.

Policy 4.5.2: Open space should be brought into the community wherever possible as a reminder of the natural setting of the community. Landscaping of residential areas should be generously oriented toward the enjoyment of the passerby. Street tree planting programs shall be pursued throughout the city to provide shade, a special character, and pedestrian comfort. Vineyard plantings within residential and commercial areas is encouraged.

Policy 4.6.1: Retain key undeveloped open space areas where views to the vineyard and hills can be maintained. Require that these areas be planted in vines or other low vegetation.

Policy 4.6.2: Discourage the use of cul-de-sacs. Where cul-de-sacs are necessary, do not allow houses to block views out to the vineyards. View corridors out from the ends of streets should be preserved.

Policy 4.6.3: Use streets to form the edge of the developed community. Maintain the edge fronting the vineyards as permanently undeveloped so that views of vineyards and beyond can be enjoyed by the general populace. Orient lots facing across the street to orient toward this view.

Policy 4.7.3: The new eastern entry via the Adams extension should be planned to maximize open space and vineyard views. Where possible, vineyards should be maintained up to the road edge. Residential development should front on the road with sufficient lot depth to allow a generous setback for sound and privacy. Large specimen street trees should be planted in residential areas to mitigate the scale of the street and encourage pedestrian and bicycle movement.

Policy 4.7.4: Existing east and west entries should be maintained in their current appearance, protecting views of vineyards and the surrounding hillsides wherever possible.

Agenda Item #6.2.

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Open Space and Conservation
Policy 6.4.11: Integrate existing significant trees into future development.

Policy 6.4.12: Require replacement trees where existing significant trees cannot be saved.

Policy 6.4.13: Require street trees as a condition of new development.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The Land Use and Growth Management Element, Community Design Element, and Open Space Element of the 2019 General Plan provide guiding and implementing policies regarding visual resources. Compared to the 1993 General Plan, the 2019 General Plan is similar in encouraging residential development that is consistent with the design and character of the City’s existing older neighborhoods (City of St. Helena 2019).

Land Use and Growth Management
Policy LU2.2: Encourage new residential development that is consistent in design, size, color, and floor area ratio (FAR) with the older residences in the neighborhood.

Policy LU2.4: Encourage the subdivision and/or development of larger parcels as Planned Unit Developments to ensure a more comprehensive and creative approach to planning the development as a single unit. This does not prohibit use of Planned Unit Developments on parcels less than three acres.

Policy LU2.5: Encourage the development of higher density housing in areas near the center of the city and close to recreation and services, such as transit, retail, and public facilities.

Policy LU2.6: Allow residential density at the higher end of the permitted range for single family development within Medium and High Density Residential Land Use designations as long as the development character of the single family area is maintained, including lot widths, orientation to street, building heights, onsite parking, traffic, and noise, among other considerations.

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

Agenda Item #6.2.

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Community Design
Policy CD1.1: Ensure high-quality design and construction through a robust design review process.

Policy CD1.8: Require, to the extent feasible, that all new development include underground utilities to minimize their negative visual impact. In addition, funding sources to underground electrical lines shall be sought so the undergrounding of existing overheard lines can occur over time.

Policy CD3.1: Limit building envelope sizes and require adequate side and rear setbacks to preserve the character of existing residential areas and to avoid overbuilt lots. Require future development to conform to the pattern and density of the neighboring areas. In order to complement existing town character and protect against incursion into vineyard agricultural areas.

Policy CD3.2: Ensure that new residential designs contribute positively to existing neighborhoods by complementing character and incorporating design features, such as front porches, façade articulation and stepbacks.

Policy CD3.3: Encourage the use of landscaping and tree plantings as buffers between sidewalks and residential uses. Discourage the removal of existing trees and adopt more comprehensive tree preservation standards.

Policy CD5.1: Preserve the visual and physical connection to agriculture by protecting views from streets, parks, and open spaces to vineyards, agriculture, and hillsides.

Where new streets are extended adjacent to agriculture, encourage hillside, and vineyard views by maintaining agricultural activities at the road edge. Existing east and west entries should be maintained in their current appearance, protecting and improving views of vineyards and the surrounding hillsides wherever possible.

Policy CD5.C: New development shall not result in significant light, glare, and noise that could affect residents, visitors, and wildlife. Lighting shall be shielded to reduce glare and shall be cast downwards. Outdoor lighting shall occur primarily for the purpose of security and safety. Upcast lighting shall be discouraged to minimize impacts on wildlife and to retain the agricultural ambience of St. Helena. All lighting shall conform to the Lighting Zone 2 requirements of Title 24 of the California Building Code.

Agenda Item #6.2.

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Open Space and Conservation
Policy OS4.1: Protect and enhance tree resources in developed and undeveloped areas. Efforts should include: adequate maintenance of street trees, requiring replacement trees where existing significant trees cannot be saved, and requiring street trees as a condition of new development.

St. Helena Zoning Ordinance
Chapter 17.164, Design Review, of the City’s Zoning Ordinance addresses requirements for design review of a project. Design review is required for any new development or the modification of the exterior of structures within the City. Design review is conducted to promote qualities in the environment which bring value to the community, to foster attractiveness and functional utility within the community, to preserve the character and quality of the community’s heritage, to protect public investments in the area, and to encourage a mix of uses within permissible use zones. If the Proposed Project is approved, future construction of residential structures within the Project area would require design review.

St. Helena Subdivision Ordinance
Chapter 16.32, Design Standards and Improvements, Section 130 of the City’s Municipal Code protects areas such as ridges, hilltops, and other scenic areas from development that impacts scenic resources. The ordinance mandates that development must ensure adequate mitigation for protection and/or preservation of scenic resources within these areas and encourages using the form of the land and vegetation to ensure separation of building areas from scenic areas.

Mitigation may require the use of plantings that are consistent and compatible with those in the area. The ordinance states that screening required for shielding of development areas should consist of natural materials of the area, including natural vegetation or land form modification to conform to the natural terrain.

The City’s Municipal Code does not contain lighting requirements pertinent to the Proposed Project and does not contain any policies that address the protection of dark skies from lighting and glare impacts.

3.1.4 Impacts
Methods of Analysis
The value attached to changes in visual character is largely subjective. This EIR does not assign a judgment of “good” or “bad” to a proposed change; rather, it identifies any “substantial adverse effect,” as defined below, as a significant environmental impact.

Agenda Item #6.2.

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September 2021 3.1-22
The determination of when changes to the visual environment become a substantial adverse effect is based on the following primary factors: (a) the existing scenic quality of an area; (b) the level of viewer exposure and concern regarding visual change; and (c) the level of actual visual change caused by the project as seen by a given viewer group. The overall visual sensitivity is first established based on existing visual quality, viewer exposure, and viewer concern. These factors are then considered together with the level of expected visual change or contrast and significance. Visual change is an overall measure of the alteration or change in basic visual attributes such as form, line, color, and texture as a result of the project. Thus, a substantial adverse effect can occur when a project results in high levels of visual change or obstruction of scenic views by sensitive receptors.

The California Environmental Quality Act (CEQA) does not require that privacy be addressed in an EIR because it is not an environmental issue. In addition, views of a project by a limited number of individuals do not constitute public views and are typically not evaluated under CEQA (See Mira Mar Mobile Community v. City of Oceanside (2004) 119 Cal.App.4th 477). This case confirmed that if agency policy does not protect private views, then impacts to such private views are not significant impacts under CEQA. The most recent update to the CEQA Guidelines also clarifies that public views “are those that are experienced from a publicly accessible vantage point.” (CEQA Guidelines Appendix G).

A description of the Project site and the surrounding area is derived from a site visit and photographs. The City’s 1993 General Plan and 2019 General Plan were both reviewed to determine what visual elements have been deemed valuable by the community. The impact analysis focuses on the manner in which development of the Project site could alter the visual elements or features that exist in or near the Project area.

Visual simulations of what the site could look like from various viewpoints were prepared for the Proposed Project, which are referenced to prepare the impact analysis. Because the Proposed Project applicant is only requesting approval of a Tentative Subdivision Map, no building designs or architectural features are available. Therefore, the visual simulations are provided only to help the reader visualize how the Project site could change once developed. The visual simulations only depict building massing and proposed landscaping, consistent with the MR zoning and the landscape plan provided by the Proposed Project applicant. To represent future development a random mix of one and two-story buildings is included. Building heights range from approximately 18-feet for a one-story residence up to 28-feet for a two-story unit. The multi-family units were assumed to be up to 30-feet tall, the maximum building height allowed under the MR zoning. The grade of the Project site, with the exception of the multi-family housing (Lot 52), is based on the Proposed Project’s grading plan. Since no grading plan was provided for the multi-family housing, all buildings and roads were placed on existing grade level. Trees are shown at an estimated 10 years growth with heights varying from 16 to 25 feet.

Agenda Item #6.2.

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All tree species are shown during the summer months with full green leaves. The Proposed Project’s proposed landscape plan shows a tree on the east side of Adams Street, directly in front of where the photo was taken (see Figure 2-6 in Chapter 2, Project Description). In Simulation 1, this tree was removed as it blocked views of the proposed development.

Adverse visual effects can include the loss of natural features or areas, the removal of urban features with aesthetic value, or the introduction of contrasting urban features into natural areas or urban settings. Natural features may include but are not limited to open space; native or ornamental vegetation/landscaping; topographic or geologic features; and natural water sources. The loss of natural aesthetic features or the introduction of contrasting urban features may have a local impact, or, if part of a larger landscape, may contribute to a cumulative decline in overall visual character. The vineyard present in the southwestern portion of the Project site would be considered a natural feature.

Urban features that may contribute to a valued aesthetic character or image may include:
structures of architectural or historic significance or visual prominence; public plazas, art or gardens; heritage oaks or other trees or plants protected by the City; consistent design elements (such as setbacks, massing, height, and signage) along a street or district; pedestrian amenities; landscaped medians or park areas; etc. There are no urban features present on the Project site.

This analysis assumes that development of the Proposed Project would comply with the City’s 1993 General Plan goals and policies and other relevant requirements; therefore, such policies and requirements are not specifically identified as mitigation.

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:
• Have a substantial adverse effect on a scenic vista.
• Substantially damage scenic resources, including, but not limited to trees, rock outcroppings, and historic buildings within a state scenic highway. • In non-urbanized areas, substantially degrade the existing visual character or quality of public views (public views are those experienced from a publicly accessible vantage point) of the site and its surroundings. If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality? • Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area.

Agenda Item #6.2.

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Regarding the visual character and quality of the site, this site exhibits characteristics of both urban and non-urban character. The Project site is within the City’s adopted Urban Limit Line, is designated for urban (medium density residential) development and is adjacent to existing residential development. The site is also adjacent to an agricultural area and the Napa River, and therefore exhibits non-urban characteristics. The City’s Municipal Code includes Chapter

16.32, Design Standards and Improvements, which provides guidance for scenic resources (Section 16.32.130), aesthetics, and design, including zoning standards for height, bulk, and setbacks which are relevant to the Project and have been reviewed.

The visual impacts of the Proposed Project are evaluated within this framework, while giving consideration to the non-urban aspects of the Proposed Project location.

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

Scenic Resources within a State Scenic Highway
As discussed previously, although the Project site is located approximately 0.2 miles from SR 29, an eligible state scenic highway, it is not visible from the highway due to intervening trees, buildings and structures. The Project site does not contain any scenic resources such as rock outcroppings, or other significant natural or historical features that are visible from a state scenic highway and the Proposed Project would not limit views of such features from SR 29. Therefore, potential impacts to scenic resources (second significance threshold listed above) are not discussed further.

Impacts and Mitigation Measures

3.1-1: Would the Proposed Project have a substantial adverse effect on a scenic vista? This impact would be less than significant.

The City’s 1993 General Plan as well as the City’s recently adopted 2019 General Plan do not designate any specific scenic resources or vistas within the City for protection. The term vista generally implies an expansive view, usually from an elevated point or open area. A scenic vista is generally defined as a viewpoint that provides expansive views of a highly valued landscape for the benefit of the general public. This can include public views of agricultural open space, vineyards, creeks, and major landscape features. Scenic vistas can also provide views of significant structures and buildings.

Agenda Item #6.2.

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The Proposed Project is proposing a Tentative Subdivision Map that includes lots for singlefamily homes as well as a 3.4-acre parcel designated for multi-family housing. Future development of the site would introduce new housing in an area that is currently undeveloped grassland with the exception of a small vineyard. Public views of the Project site are limited and generally available from the gravel maintenance road/public trail that borders the site along the north and northwest in addition to nearby public and private roads including Adams Street to the south, Starr Avenue to the southeast, and Del Rio Court to the northeast of the site. Public views from these areas include views of green grass during the early spring before the grass areas turn brown through the remainder of the year. Included are views of a mature vineyard with elevated trellises located in the south/southwest portion of the site. The Project site does not represent a scenic vista because it does not contain unique resources that would be considered a highly valued landscape enjoyed by the public, nor is the site visible from an elevated area that affords public views of a highly valued landscape. In addition, given the size and location of the Project site it does provide expansive views that constitute a vista. Views of the mountains and hillsides to the north and northwest of the site would be considered a scenic vista.

The 1993 General Plan does not contain any goals or polices specific to protecting or preserving scenic vistas, but Policy 4.5.1 of the 1993 General Plan is intended to preserve a sense of a strong connection to the surrounding agricultural open space and hillsides by maintaining views of vineyards, hillsides, creeks and major landscape features. This is essentially re-stated in Policy CD5.1 in the 2019 General Plan, which intends to “Preserve the visual and physical connection to agriculture by protecting views from streets, parks, and open spaces to vineyards, agriculture, and hillsides.” The Proposed Project has been designed to protect views of the surrounding hillsides and open spaces areas through the orientation of Starr Avenue and Adams Street.

Development of the Project site would be required to comply with the City’s land use, and development guidelines set forth in the City’s Municipal Code. Specifically, Chapter 16.32, Design Standards and Improvements which requires scenic areas, defined as areas that contain ridges or hilltops, to include adequate mitigation for protection and/or preservation of the scenic resources, defined as intermittent, seasonal, or permanent waterways; tidal marshes or freshwater marshes; significant wildlife habitat; or significant archeological, paleontological or historic sites; undergrounding of utilities unless exempted; and grading plans that maximize retention of natural landforms such as rolling hills and areas of extensive vegetation. In addition, the Proposed Project applicant is required to comply with Chapter 17.164, Design Review, of the City’s Zoning Ordinance which sets forth specific design standards for residential development. Although development of the Project site would remove a majority of the existing vineyard and open space on-site and may decrease unobstructed views of the hillsides to the north and west visible from public viewpoints, the Project site itself is not considered a scenic Agenda Item #6.2.

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vista, does not contain a highly valued landscape, nor is it located within a scenic vista identified in either the 1993 General Plan or the 2019 General Plan. Therefore, the Proposed Project would not have a substantial adverse impact on a City-designated scenic vista and the impact would be less than significant.

Mitigation Measures
None required.

3.1-2: Would the Proposed Project conflict with zoning and other regulations that govern scenic quality or substantially degrade the existing visual character or quality of public views of the site and its surroundings, or conflict? This impact would be less than significant.

The Proposed Project includes a Tentative Subdivision Map, which, if approved, would allow for development of the Project site with single-family residential units as well as accessory dwelling units, attached multifamily residential units, roads, and landscaping. The Project site is presently undeveloped with the exception of an existing vineyard located in the southwestern portion of the site, as described in Section 3.1-2. Development of the Project site would change the undeveloped character of the site from vineyard and annual grasslands to a developed urbanized environment. Based on the Proposed Project’s grading plan the proposed elevation of the site would be approximately 4 feet higher than the existing elevation of surrounding properties, primarily along the southeast boundary. Vineyards in the southwestern “panhandle” portion of the Project site would be retained, but the remainder of the existing vineyard would be removed to accommodate development.

Because the current Proposed Project entitlement is a Tentative Subdivision Map, once housing plans are submitted the Proposed Project applicant is required to comply with the City’s Design Review Ordinance (Chapter 17.164 of the City’s Zoning Ordinance) and undergo design review to ensure the proposed development is visually consistent and compatible with the applicable General Plan and with adjacent buildings as well as the existing environment.

It is assumed future development would comply with the building height and mass requirements of the site’s MR zoning which allows buildings up to 30 feet tall, accessory buildings up to 15 feet tall, and widths not exceeding 60% of the width of the lot as measured at the front elevation (see Section 17.40.060 of the Zoning Code). The Proposed Project is consistent with the type and density of existing residential development in the Project vicinity, and is consistent with 1993 General Plan Policy 2.6.15, which encourage new residential development consistent with the scale and character of the older residential neighborhoods in the City. Under the 1993 General Plan MDR land use designation a density of between 5.1 to 12.0 dwelling units per acre (du/acre) is permitted. The Proposed Project is proposing an average density of 5.1 du/ac. In Agenda Item #6.2.

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addition, the Proposed Project is also consistent with Policy LU2.2 included in 2019 General Plan, which is similar to the previous policy in encouraging new residential development that is consistent in design and floor area ratio with older residences in the neighborhood, as well as Policy CD3.1 which limits building envelopes and requires side and rear setback to preserve the character of existing residential areas. Proposed streets also include landscape strips or medians for street trees. Appropriate landscaping is required under the City’s Design Review Ordinance (Chapter 17.164) and Subdivision Ordinance (Chapter 16.32 Section 130).

The Proposed Project is within the City’s Urban Limit Line and would be consistent with the type and character of residential development adjacent to the site. The design of the subdivision maintains the existing street pattern and maintains existing street views of the surrounding area, consistent with 1993 General Plan Policies 4.4.2, 4.4.4, 4.5.1 and 4.6.3, and 2019 General Plan Policy CD5.1. New and extended streets within the Project site would be consistent with existing roadway patterns, per 1993 General Plan Policy 4.4.2. Importantly, Street “B” would terminate in an easement that would maintain views of the riparian corridor and hills to the northeast (see Figure 2-4, in Chapter 2, Project Description). On-site electrical, natural gas and telecommunications connections would all be installed subsurface and no overhead facilities would be provided, consistent with 2019 General Plan Policy CD1.8 which encourages undergrounding of such services to reduce visual clutter. The Proposed Project would not conflict with the underlying MR zoning designation and is generally consistent with goals and policies that address visual resources in the City’s 1993 General Plan and 2019 General Plan and the impact would be less than significant.

Due to the location of the Project site adjacent to the 1993 General Plan Urban Limit Line and near rural undeveloped land to the north/northwest and the Napa River to the northeast, an analysis of the how development of the site could degrade the existing visual character and affect the quality of public views of the Project site and its surroundings is included. Due to the flat topography of the City and dense development to the west and south of the Project site along with trees and other landscaping, views of the site are limited and primarily available from private property (i.e., backyards), at the terminus of Starr Avenue and Adams Street, and along Del Rio Court (a private street) within the immediate vicinity of the site. The gravel maintenance road/public trail that borders the north/northwest boundary of the site used by the public as a walking trail also provides public views of the site. Long-range views of surrounding wooded hillsides are visible from public areas surrounding the site due to its flat topography and lack of tall intervening structures. The Proposed Project would modify long-range views of existing vineyards located to the west and on the Project site as well as views of rolling hillsides which would be partially blocked by development of new residences. However, although long-range views of hillsides and views of the on-site vineyard and open space are available in the vicinity of the Project site, these views are not unique in that views of these features are available throughout the City.

Agenda Item #6.2.

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To illustrate how development of the site could look and how it could affect public views and the existing visual character, visual simulations have been prepared. The visual simulations do not provide building designs or architectural features because the Proposed Project applicant is only requesting approval of a Tentative Subdivision Map at this time, thus the visual simulations only include building massing and proposed landscaping to demonstrate how the Project site could be altered with development.

A description of these viewpoints is included in the discussion below and the location of viewpoints is provided on Figure 3.1-6. These viewpoints include public views of the Project site from Starr Avenue, the extension of Adams Street, the gravel maintenance road, and from Del Rio Court (a private street). As described previously, vineyards in the southwestern “panhandle” portion of the Project site would not be removed. However, these viewpoints shown in Figure

3.1-7 through 3.1-10 include those areas where the vineyards would be removed and visual changes to the Project site would be greatest.

As shown in Figure 3.1-7, the view looking northeast from the proposed extension of Adams Street currently includes views of the existing maintenance road, a portion of the existing vineyard, open space with green grasses, evergreen trees in the background to the northeast bordering homes, and hillsides in the background to the north. The Proposed Project would change views at this viewpoint through removal of the vineyards and development of roads, residences, and new landscaping. The existing maintenance road at the forefront of this view would be replaced with a small section of paved road (Adams Street). Proposed Project streets also include landscape strips or medians for street trees which would reduce the effects of visual change and provide consistency with the surrounding neighborhoods. Hillsides in the background would still be available to the north, but trees bordering residences closer to the northeast would be blocked from view by the new residential units. While these views from the existing eastern terminus of Adams Street would change, as shown in the visual simulation provided in Figure 3.1-7, the road would form an edge between the proposed residential development and agricultural uses to the north and northwest and would preserve public views to the north and west from the existing trail, consistent with 1993 General Plan Policy 4.4.4 to leave open views of agricultural lands and hillsides, Policy 4.6.3 to maintain the edge fronting vineyards as undeveloped to preserve views, and Policy 4.7.3 to maximize open space and vineyard views near Adams Street.

Agenda Item #6.2.

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Agenda Item #6.2.

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Simulation 1
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Existing Conditions - Looking northeast from the proposed extension of Adams Street Visual Simulation - Looking northeast from the proposed extension of Adams Street Agenda Item #6.2.

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Agenda Item #6.2.

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As shown in Figure 3.1-8, public views from the proposed extension of Starr Avenue looking north and northwest across the Project site would change from the existing undeveloped character to a developed environment. Existing views include limited views of the hillsides to the north and evergreen trees bordering residential uses farther to the east as well as green grassland that characterizes the Project site. A portion of the vineyard is also visible, with plantings arranged in a parallel fashion running northwest to southeast. The visual simulation in Figure 3.1-8 illustrates how public views could be affected by the Proposed Project due to the introduction of new buildings into the area. The extension of Starr Avenue would maintain the existing northwest view of open space and the hills in the background, although new houses would partially restrict this view from the existing road terminus, as shown in the figure. The existing vineyards would be replaced with residential homes and a paved road would replace the on-site grassland. The change to the Project site would be similar to the views presented in Figure 3.1-7 from the extension of Adams Street.

Figure 3.1-9 shows the existing and proposed views from the area looking south/southeast from the maintenance road. Existing long-range views include evergreen trees and hillsides in the distance. On the Project site itself, there is a view of a stretch of undeveloped green grassland in the foreground with vineyards visible in the distance. The Proposed Project would change public views of this area by introducing residential homes and a paved road (Street “C”) surrounded by street trees. As shown in the visual simulation in Figure 3.1-9, new housing development in the foreground would be generally consistent with the height of existing trees in the background, ensuring that views of the hillsides to the south from this area are maintained.

The Tentative Subdivision map includes a setback of undeveloped space between the proposed Street “C” and the maintenance road, as shown in the visual simulation.

As shown in Figure 3.1-10, the existing view generally looking west from Del Rio Court includes views of a large grassy depression in the center of a stretch of undeveloped grassland (City’s detention basin). A few shrubs exist around the edge of this depression. There are also views of evergreen trees farther west, with buildings visible in the distance, along with hillsides in the background. Existing views of the Project site are generally limited from this area due to topography. The Proposed Project would alter the site from undeveloped grassland and vineyards to single-family homes, but views of the open space (including the City’s detention basin) in the foreground and distant hills would still be visible as shown in Figure 3.1-10. Views of distant buildings and a cluster of evergreen trees would be replaced by new homes bordered by fences.

As shown in the above visual simulations, the Proposed Project would remove a majority of the existing vineyard and open space that characterize the site and would decrease unobstructed views of the hillsides to the north and west visible from public viewpoints.

However, views of agricultural and mountainous features in the City are not unique to the Agenda Item #6.2.

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Project site such that the Proposed Project would substantially impact publicly available views. As mentioned, additional discretionary approvals and Design Review would be required for specific Proposed Project components, as the current Proposed Project entitlement is only approval of a Tentative Subdivision Map. Therefore, the Proposed Project would not conflict with applicable regulations governing scenic quality or substantially degrade the existing visual character or quality of public views of the site and its surroundings and the impact to visual resources would be less than significant.

Mitigation Measures
None required.

3.1-3: Would the Proposed Project create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? This impact would be potentially significant.

Development of the Project site would introduce new sources of lighting including exterior building lights and overhead streetlights along all residential streets. Indoor and outdoor lighting associated with new residences and streetlights would increase lighting in the Project area relative to existing conditions. Additionally, sun reflecting off the windows of the proposed development could create daytime glare. However, this type of development does not include large expanses of glass or reflective building materials that can result in daytime glare conditions. Therefore, the potential for Proposed Project development to result in glare that could adversely affect daytime views in the area and result in an impact is less than significant.

All lighting would be required to conform to the Lighting Zone 2 requirements of Title 24 of the California Building Code. The City does not have any adopted Design Guidelines or policies in the 1993 General Plan that specify lighting be shielded and downward focused to avoid spillover light effects. However, the 2019 General Plan does include Policy CD5.C which requires new development install lights that are shielded and cast downwards, and to conform to the Lighting Zone 2 requirements of Title 24 of the California Building Code. Because new light sources would be introduced into an area that is currently undeveloped which could adversely affect nighttime views, and the City’s 1993 General Plan and Zoning Ordinance do not include standards for lighting this is considered a potentially significant impact.

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Existing Conditions - Looking west from Del Rio Court
Visual Simulation - Looking west from Del Rio Court
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Mitigation Measures
Implementation of Mitigation Measure AES-1 requires lighting design guidelines be developed for the Proposed Project and that Proposed Project lighting be designed to minimize glare and light spillover. Compliance with this mitigation measure would ensure impacts related to lighting would be reduced to less than significant.

AES-1: To minimize spillover light while ensuring adequate nighttime security, the Project applicant shall prepare lighting design guidelines for the Project to be reviewed and approved by the City as part of the Design Review process. The lighting design guidelines shall include a lighting plan noting fixtures and lumens, and standards such as, lighting is to be shielded and downward focused to reduce glare and spillover light, up cast decorative lighting shall be limited to minimize effects on wildlife and to retain the rural ambience of the area, and the use of mirrored glass shall not be permitted. The lighting guidelines shall conform with Lighting Zone 2 of Title 24, Part 6, of the California Code of Regulations. The guidelines and lighting plan shall be approved as part of the Design Review application.

3.1.5 Cumulative Impacts
The cumulative analyses for aesthetics, including light and glare, is based on the buildout of development identified in the City’s 1993 General Plan. While the Proposed Project is required to be evaluated under the 1993 General Plan, any changes relative to the 2019 General Plan are also evaluated for informational purposes. The geographic scope of the cumulative impact analysis for aesthetics includes the area that comprises the viewshed in which the Project site is visible, and the views visible from the Project site, which includes development in the immediately surrounding areas.

As the Project site is not considered a scenic vista, this issue is not discussed as a cumulative impact.

3.1-4: Would the Proposed Project contribute to cumulative changes in the existing visual character or conflict with applicable regulations governing scenic quality? The Project’s contribution would not be considerable.

As stated above, the cumulative context for aesthetics includes the area that comprises the viewshed in which the Project site is visible. There were no cumulatively significant aesthetics impacts identified in the 1993 General Plan EIR or the 2019 General Plan EIR. It was determined that the City’s design review process, in combination with General Plan policies would maintain the high-quality visual character of existing and future development, would limit impacts to agricultural lands, and would primarily contain growth within the Urban Limit Line, ensuring that cumulative aesthetic impacts would be less than significant. Thus, there is no existing cumulative impact related to visual character or scenic quality.

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As there is no existing cumulative impact related to this topic, the Proposed Project would not have a considerable contribution. As discussed under Impact 3.1-2, the Proposed Project would alter the existing visual character of the Project site by developing a residential subdivision on land that is currently undeveloped. However, this development would occur consistent with both the 1993 General Plan and also the 2019 General Plan 0 policies, zoning, and design review regulations to address visual quality in the City. The 2019 General Plan includes policies to minimize light and glare and a policy to encourage undergrounding of electric lines to reduce visual clutter, Policies CD5.C and CD1.8, respectively. At a localized level, there are no approved or reasonably foreseeable projects that would be visible from the Project site, with the exception of a single-family residence, accessory dwelling unit and barn under construction to the west of the Project site. With consideration of the above factors and the absence of an existing cumulative impact, the Proposed Project’s contribution would not be considerable.

Mitigation Measures
None required.

3.1-5: Would the Proposed Project contribute to a cumulative increase in light and glare? The Project’s contribution would not be considerable.

The cumulative context for light and glare would be other development in the surrounding area that could contribute to an increase in light and glare. As discussed under Impact 3.1-3, development of residential uses would introduce new sources of light in the area. The Proposed Project, along with existing and future development within the City, would contribute to the existing ambient light in the Project vicinity by introducing streetlights, landscape lighting, and interior and exterior buildings lights. The 1993 General Plan EIR found lighting to be a potentially significant Proposed Project impact, requiring mitigation. As undeveloped areas transition from rural to urban character, the amount of light and glare would increase due to new buildings, structures, streetlights, and vehicle lights. However, the 1993 General Plan EIR concluded that compliance with General Plan policies and the City’s design review process would be adequate to mitigate cumulative aesthetic impacts. The 2019 General Plan also determined that the design review process and General Plan policies would ensure that the cumulative impact would be less than cumulatively considerable. Thus, there is no existing cumulative impact related to light and glare.

As there is no existing cumulative impact related to light and glare, the Proposed Project would not have a considerable contribution. The City does not have any adopted Design Guidelines or policies in the 1993 General Plan that specify lighting be shielded and downward focused to avoid spillover light effects. However, the 2019 General Plan does include Policy CD5.C which requires new development to be shielded and cast downwards, and to conform to the Lighting Agenda Item #6.2.

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Zone 2 requirements of Title 24 of the California Building Code. Because the Proposed Project would add new light sources to an area that is currently undeveloped, it would contribute a small increase in the overall amount of light in the City. This impact would be mitigated by Mitigation Measure AES-1 as described above under Impact 3.1-3, making the Proposed Project consistent with Policy CD 5.C. With consideration of the above factors and the absence of an existing cumulative impact related to light and glare, the Proposed Project’s contribution would not be cumulatively considerable.

Mitigation Measures
See Mitigation Measure AES-1. Compliance with Mitigation Measure AES-1 mitigates this impact and no additional mitigation is required.

3.1.6 References
Caltrans (California Department of Transportation). 2018. California Scenic Highway Mapping System:

Napa County. Accessed November 12, 2018. Available at: http://www.dot.ca.gov /hq/LandArch/16_livability/scenic_highways/index.htm.

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

City of St. Helena. 2010. St. Helena General Plan Update. August 2010. Prepared by ESA.

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.

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3.2 AGRICULTURE AND FORESTRY RESOURCES

3.2.1 Introduction
This section describes agricultural resources, including farmland and forestland, and discusses applicable federal, state, and regional regulations pertaining to agriculture and forestry resources. This section evaluates the potential effects on agricultural and forestry resources associated with development of the proposed Hunter Subdivision Project (Proposed Project).

Comments received in response to the Notice of Preparation included concerns regarding removal of the existing vineyard on the Project site, loss of Prime Farmland and farmland/agricultural resources and potential mitigation to address loss of farmland, and impacts on adjacent vineyard soils and crops due to homeowner pesticide or fertilizer use. Impacts related to homeowner use of pesticides, fertilizer, and other household hazardous wastes are addressed in detail in Section 3.8, Hazards and Hazardous Materials. As stated in Section 3.8, households typically use small amounts of household hazardous wastes at quantities too small to result in a significant hazard to the public or the environment. Thus, this issue as it relates to agricultural resources is not discussed in this section. A copy of the Notice of Preparation and comments received is included in Appendix A.

Information referenced to prepare this section includes the California Department of Conservation Farmland Mapping and Monitoring Program and City planning documents (including the 1993 General Plan and the 2019 General Plan1). The California Land Evaluation and Site Assessment (LESA) Model was used to assess potentially significant effects on agricultural lands and the model outputs are provided in Appendix B. Other sources consulted are listed in Section 3.2.6, References.

3.2.2 Environmental Setting
Farmland
Agriculture has historically been a part of the City of St. Helena (City), with the City’s agricultural land primarily consisting of vineyards due to its deep alluvial soils that are conducive to growing wine grapes (City of St. Helena 1993). Within the City, agricultural uses, including wineries, account for 916 acres (25%) of the total land area. Agricultural areas are primarily located adjacent to the City’s Urban Limit Line (City of St. Helena 2018). The majority of the Project site contains undeveloped land consisting of nonnative grasses, with the exception of a small vineyard in the southwestern portion of the site that occupies approximately 6.8 acres or 40% of the Project site along with less than an acre of vineyards located in the “panhandle” portion of 1 The “General Plan Update 2040,” adopted in 2019, is referred to in this EIR as the “2019 General Plan.” Agenda Item #6.2.

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the site. There are no forest resources present on the site but there are some trees located adjacent to the southeast boundary of the Project site. The elevation of the Project site 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. Lands to the north of the Project site, between Library Lane and Silverado Trail North are primarily agricultural, with vineyards located beyond the proposed Adams Street extension and the levee along the Napa River. The Napa River is located approximately 0.1 miles to the north/northeast of the Project site. Single-family and multi-family residential development is located to the south and southeast, and office uses are located immediately adjacent to the site’s western boundary at the terminus of Adams Street. 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 north/northeast.

The Project site is designated as high density housing in the 1975 St. Helena General Plan, as Medium Density Residential (MDR) in the City’s 1993 General Plan (City of St. Helena 1993), and as MDR in the current 2019 General Plan (City of St. Helena 2019). Land designated as Medium Density Residential (MDR) typically is for residential purposes, and provides for singlefamily detached and attached homes, secondary residential units, public and semi-public uses, and similar and compatible uses. The zoning designation for the Project site is also Medium Density Residential (MR) (City of St. Helena 2018).

Farmland Classification
The California Department of Conservation (DOC), Division of Land Resources Protection, operates the Farmland Mapping and Monitoring Program (FMMP). The FMMP maps the state’s farmland resources and monitors the conversion of farmland to (and from) other land uses. As shown in Figure 3.2-1, FMMP Classification, the FMMP categorizes the eastern portion of the Project site as Farmland of Local Importance. The western portion of the Project site is predominantly designated as Prime Farmland, with portions of Farmland of Statewide Importance and Urban and Built-Up Land in the westernmost area of the Project site. Table 3.2- 1 provides acreages for the various farmland categories within the site.

Table 3.2-1
Important Farmland
Farmland Mapping and Monitoring Program Category Acreage Prime Farmland 5.8
Farmland of Statewide Importance 0.6
Farmland of Local Importance 9.0
Urban and Built Up Land (including existing roadways) 0.8 Total 16.2
Source: DOC 2017.

Note: The acreage/boundaries between the parcel data information and Napa County GIS data results in a 0.7-acre discrepancy.

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Hunter Subdivision Project
SOURCE: Bing Maps 2019; CA Department of Conservation 2016 0 150 300Feet
Project Boundary
FMMP
D, Urban and Built Up Land
L, Farmland of Local Importance
P, Prime Farmland
S, Farmland of Statewide Importance
FIGURE 3.2-1
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Land to the north and east of the Project site is designated as Prime Farmland, and land to the northwest of the site is designated Farmland of Statewide Importance. The FMMP categories relevant to the Project site are defined as follows:

Prime Farmland
“Prime Farmland” is farmland with the best combination of physical and chemical features able to sustain long term agricultural production. This land has the soil quality, growing season, and moisture supply needed to produce sustained high yields. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date.

Farmland of Statewide Importance
Farmland similar to Prime Farmland but with minor shortcomings, such as greater slopes or less ability to store soil moisture. Land must have been used for irrigated agricultural production at some time during the 4 years prior to the mapping date.

Farmland of Local Importance
Land of importance to the local agricultural economy as determined by each county’s board of supervisors and a local advisory committee.

Urban and Built-up Land
Land occupied by structures with a building density of at least 1 unit to 1.5 acres, or approximately 6 structures to a 10-acre parcel. This land is used for residential, industrial, commercial, construction, institutional, public administration, railroad and other transportation yards, cemeteries, airports, golf courses, sanitary landfills, sewage treatment, water control structures, and other developed purposes.

Soil Types
The United States Department of Agriculture Natural Resources Conservation Service (NRCS) conducts soil surveys and creates maps representing the location and type of soil in order to aid in agricultural, conservation, and land use decisions. The NRCS identifies the following soils as occurring on the Project site (USDA 2018):
• Bale clay loam, 0 to 2% slopes
• Bale clay loam, 2 to 5% slopes
• Cole silt loam, 0 to 2% slopes
• Cortina very gravelly loam, 0 to 5% slopes, moist
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The Storie Index is a rating system that is used to classify soils that could be used for irrigated agriculture in California. The Storie Index Rating system ranks soil characteristics according to their suitability for agriculture from Grade 1 soils (80 to 100 rating), which have few or no limitations for agricultural production to Grade 6 soils (less than 10), which are not suitable for agriculture. Under this system, soils deemed less than prime can function as prime soils when limitations such as poor drainage, slopes, or soil nutrient deficiencies are partially or entirely removed. Soil units are also rated based on four properties: degree of soil profile development, texture of the surface layer, steepness of slope, and drainage class, landform, erosion class, flooding and ponding frequency and duration, soil pH, soluble salt content as measured by electrical conductivity, and sodium adsorption ratio (USDA 2018). The Storie Index Ratings for soils on the Project site are shown in Table 3.2-2.

Table 3.2-2
Storie Index Ratings for On-Site Soils
Soil Type Storie Index Rating Percent of Property Area
Bale clay loam, 0 to 2% slopes Grade 2 – Good 22.3%
Bale clay loam, 2 to 5% slopes Grade 3 – Fair 53.2%
Cole silt loam, 0 to 2% slopes Grade 2 – Good 21.0%
Cortina very gravelly loam, 0 to 5% slopes, moist Grade 3 – Fair 3.5% Source: USDA 2018.

As shown in Table 3.2-2, the majority of the Project site, approximately 57%, contains soils that are classified as fair for irrigated agricultural production. The remainder of the site, approximately 43% contains soil units that are classified as good for irrigated agricultural production.

The Project site is not under a Williamson Land Act contract and does not contain any forest or timberland and is not zoned for forest land, timberland, or timberland production.

3.2.3 Regulatory Setting
Federal Regulations
Federal agencies must consider the impacts to Prime Farmland resulting from their actions under the Farmland Protection Policy Act (7 USC Section 4201 et seq.). This requirement does not apply to the Proposed Project.

State Regulations
The following state regulations pertaining to agricultural resources would apply to the Proposed Project.

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California Civil Code Section 3482.5
Section 3482.5 of the California Civil Code specifies that no agricultural activity, operation, or facility that is conducted properly in the same location for more than three years shall be considered a nuisance to new uses in its vicinity, unless it was considered a nuisance since the time it began. This regulation also applies to activities of a district agricultural association.

Williamson Act
The Williamson Act (California Government Code Section 51200), also known as the California Land Conservation Act of 1965, is the premier legislation for the protection of agricultural land in California. The act underscores the importance of preserving a maximum amount of the state’s agricultural land as an economic asset that provides for the generation of adequate and nutritious food resources for the nation and state into the future. The Williamson Act operates through 10-year contracts with agricultural landowners that confirm that agricultural land is being preserved as the land’s best use while providing a substantial property tax break for the landowner. The property’s agricultural value is assessed and the landowner under contract is dismissed from property taxes according to the property’s urban development potential. The Project site does not contain any land under a Williamson Act contract.

Farmland Mapping and Monitoring Program
The FMMP is a non-regulatory program implemented by the DOC, Division of Land Resource Protection. Government Code Section 65570 mandates the FMMP to biennially report to the Legislature on the conversion of farmland and grazing land, and to provide maps and data to local government and the public. FMMP produces Important Farmland Maps, which are a hybrid of resource quality (soils) and land use information, based on the prior federal NRCS program.

Land is classified into eight categories. Prime Farmland, Farmland of Statewide Importance, and Unique Farmland are considered “Important Farmland” for the purposes of the California Environmental Quality Act (CEQA) (the conversion of which may be a significant impact).

Local Regulations
The following local/regional regulations pertaining to agriculture would apply to the Proposed Project.

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City of St. Helena 1993 General Plan
The Open Space and Conservation Element and Land Use and Growth Management Element of the City of St. Helena 1993 General Plan provides guiding policies regarding agricultural and forestry resources, including the following:

Growth Management
Policy 2.6.5: Encourage the continuation of agricultural and low-intensity uses adjacent to the Urban Limit Line.

Agriculture
Policy 2.6.58: Promote the continuation of agricultural activities within and adjacent to the City.

Policy 2.6.59: Protect prime agricultural land and prime vineyard land from premature and/or unnecessary urban encroachment.

Policy 6.3.1: Maintain agriculture as the mainstay of the local economy by preserving agriculturally-designated lands as an invaluable and irreplaceable open space resource.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The Open Space and Conservation Element and Land Use and Growth Management Element of the City of St. Helena 2019 General Plan provides guiding policies regarding agricultural and forestry resources, including the following:

Growth Management
Policy LU1.3: Support agricultural and low-intensity uses beyond the Urban Limit Line.

Agriculture
Policy LU5.1: Discourage conversion of existing farmland to non-agricultural uses.

Policy LU5.2: Encourage the County to continue to promote agricultural uses and to limit further development in unincorporated areas surrounding the city.

Policy LU5.3: Strictly limit development on properties existing at the time of the adoption of this General Plan that are designated as agricultural land.

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St. Helena Municipal Code
Chapters 17.32 through 17.60 and 17.68 of the St. Helena Municipal Code protect agricultural operations on agricultural land within the City by limiting the circumstances under which agricultural operations may be deemed to constitute a nuisance. The City’s municipal code contains the following “right-to-farm” provision in the regulations for each nonagricultural zoning district:

Property owners within this district shall recognize that there exists a right to farm properties within the district and in the vicinity of the district. There is a good faith expectation that no complaints will occur regarding legal normal agricultural activities on properties in the district or in the vicinity of the district. Such activities may include day or night disbursement of chemicals, and creation of dust, noise, or fumes.

In addition, Municipal Code Section 17.04.100 (Cultivated agricultural use within established zoning districts) specifies the following:

It is the policy of the city as expressed in the general plan to recognize and provide for cultivated agriculture within the city limits. Cultivated agricultural uses are permitted within the A-20 zoning district and regulated by use permit in the woodlands and watershed zoning district. It is the intent of the city to allow cultivated agricultural uses including, but not limited to, farming, horticulture, floriculture and viticulture, but excluding animal husbandry and livestock farming, in all zoning districts within the urban limit line prior to establishment of urban land uses. Allowing cultivated agriculture within the urban limit line shall not compromise the long-term objective of providing for designated urban uses.

Water used for cultivated agriculture shall be in conformance with Section

13.04.100 of this code.

3.2.4 Impacts
Methods of Analysis
The LESA Model was used to evaluate potential impacts to agricultural land resulting from development of the Project site. The LESA Model is a point-based approach for rating the relative importance of agricultural land resources based upon specific measurable features. The LESA was first developed in 1981 by the NRCS to provide an objective rating system for the agricultural suitability of land. The development of California’s LESA Model was the result of Senate Bill 850 (Chapter 812/1993), which charged the Resources Agency, in consultation with the Governor’s Office of Planning and Research, with preparing an amendment to Appendix G of the CEQA Guidelines concerning agricultural lands. This model ensures a quantitative and Agenda Item #6.2.

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consistent approach to determining potentially significant impacts to agricultural resources during the environmental review process. The LESA Model evaluates various characteristics of a project site, including soil resource quality, project size, water resource availability, surrounding agricultural lands, and surrounding protected resource lands. These factors are rated, weighted, and combined to produce a single numeric score that can be used to determine significance. The final scoring is based on a scale of 100 points. Thresholds for significance are based on both the total LESA score as well as the component Land Evaluation (LE) and Site Assessment (SA) subscores (DOC 1997). Table 3.2-3 includes the LESA Model scoring thresholds. A copy of the model outputs is included in Appendix B.

Table 3.2-3
LESA Model Scoring Thresholds
Scoring Significance
0 to 39 Points Not Considered Significant
40 to 59 Points Considered Significant only if LE and SA subscores are each greater than or equal to 20 points 60 to 79 Points Considered Significant unless either LE or SA subscore is less than 20 points 80 to 100 Points Considered Significant
Source: DOC 1997.

The LE considers the quality of the soils on a project site, as measured by Land Capability Classification and the Storie Index of the soils. The Land Capability Classification indicates the suitability of soils for most kinds of crops. Groupings are made according to the limitations of the soils when used to grow crops, and the risk of damage to soils when they are used in agriculture. The Storie Index provides a numeric rating (based upon a 100-point scale) of the relative degree of suitability or value of a given soil for intensive agriculture. The rating is based upon soil characteristics only. The NRCS Web Soil Survey was used to determine soil types and properties on the Project site.

The SA considers the size of a project site, the availability of water for agricultural use, the amount of active agricultural uses around the project site, and the amount of protected land (including Williamson Act contracts, publicly owned lands used for open space or recreational uses, and easements which restrict urban development). The SA portion was primarily based on City, County of Napa (County), and other public GIS data and the DOC FMMP, and the well report filed with the Department of Water Resources for the on-site groundwater well. The Proposed Project setting was developed by reviewing FMMP data and Williamson Act contract information from the DOC. This review was supplemented with field observations (as part of the biological resource fieldwork).

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Thresholds of Significance
Consistent with Appendix G of the CEQA Guidelines, a significant impact could occur if development of the Proposed Project would do any of the following:
• Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use. • Conflict with existing zoning for agricultural use, or a Williamson Act contract. • Conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code section 12220(g)), timberland (as defined by Public Resources Code section 4526), or timberland zoned Timberland Production (as defined by Government Code section 51104(g)).
• Result in the loss of forest land or conversion of forest land to non-forest use. • Involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland, to non-agricultural use or conversion of forest land to non-forest use.

As shown in Table 3.2-3, the loss of agricultural resources would be considered significant only if the individual LE and SA subscores are each greater than or equal to 20 points.

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

Conflict with Williamson Act Contract/Conflict with Lands Zoned Forest Land or Timberland/Loss or Conversion of Forest Land
The Project site does not include forest lands, land zoned for agricultural use, or timberland, nor does the Project site contain an active Williamson Act contract; therefore, there would be no impact to conflicting with existing zoning for agricultural use, forest or timberland resources, or removal of a Williamson Act contract. Thus, these issues (second, third and fourth significance threshold listed above) are not further evaluated.

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Impacts and Mitigation Measures

3.2-1: Would the Proposed Project convert Prime Farmland and Farmland of Statewide Importance, as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use? This impact would be less than significant.

The Project site includes 5.8 acres of Prime Farmland and 0.6 acres of Farmland of Statewide Importance (as defined by the FMMP) that would be converted to urban uses as a result of Proposed Project implementation (see Table 3.2-1). The site also includes land designated as Farmland of Local Importance and Urban Land. Due to the presence of 6.4 acres of “Important Farmland,” the LESA Model (Appendix B) was used to evaluate the quality of agricultural lands on the Project site to determine the significance of potential Proposed Project impacts. As described above, under Methods of Analysis, the LESA Model is used to provide a quantitative and consistent approach to determining potentially significant impacts to agricultural resources during the environmental review process. The model results in individual scores for the LE and SA factors, along with a total score out of 100 possible points.

The dominant soil type on the Project site is Bale clay loam (see Section 3.6, Geology and Soils), which has a relatively high Land Capability Classification and average to above-average Storie Index. This resulted in a moderate LE score. The relatively small size of the Project site and the amount of urban land near the site resulted in a low SA score, despite the relatively good availability of water (due to the on-site irrigation well). The model returned an LE score of 35 and a SA score of 13.8 for a total score of 48.8 (see Appendix B). As shown in Table 3.2-3, the loss of agricultural resources would be considered significant only if the individual LE and SA subscores are each greater than or equal to 20 points. Therefore, impacts associated with the removal of prime farmland and farmland of statewide importance would be less than significant.

Mitigation Measures
None required.

3.2-2: Would the Proposed Project involve other changes in the existing environment which, due to their location or nature, could result in conversion of farmland, to non-agricultural use? This impact is less than significant.

Conversion of the Project site to developed uses may impact nearby agricultural operations to the north, northeast and northwest. Existing agricultural operations may become constrained, due to concerns with the effects of dust, odor, noise, and pesticide-use from future Proposed Project residents. In addition, urban effects, such as vandalism, garbage, and predation by domestic animals (cats and dogs) can also impact agricultural uses. These are often identified as “edge effects,” as the urban edge interacts with adjacent agricultural activities.

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There is agricultural land to the north and northwest of the Project site, within the City boundaries, that is currently in active agricultural production. This land is designated as Prime Farmland and Farmland of Statewide Importance (FMMP 2017). The City’s Municipal Code (Chapters 17.32 through 17.60 and 17.68) includes provisions that require property owners adjacent to agricultural operations to recognize that adjacent properties have the right to farm and that there is a good faith expectation that the adjacent neighbors would not complain to the City regarding legal normal agricultural activities, including day or night disbursement of chemicals, and creation of dust, noise, or fumes. This protects agricultural operations and uses within the vicinity of the Project site. There is an existing trail adjacent to a gravel maintenance road also used by the public as an informal trail which borders the site along the north/northwest. No modifications to the trail or maintenance road are proposed and these existing uses would help provide a buffer between adjacent agricultural activities and the Project site. The development of residences on the Project site would not directly or indirectly result in conversion of properties under active agriculture to the north and northwest to non-agricultural uses. Therefore, impacts would be less than significant.

Mitigation Measures
None required.

3.2.5 Cumulative Impacts
The effects of the Proposed Project, when considered with other projects in the region, could result in a cumulative impact to the loss of farmland resources. The cumulative context for the analysis of agricultural resources is Napa County.

3.2-3: Would the Proposed Project contribute to cumulative impacts associated with the loss or conversion of existing agricultural resources? The Project would result in a less than considerable contribution.

As stated in the Napa County General Plan, agriculture is and will continue to be the primary land use in Napa County (Napa County 2008). According to the DOC’s FMMP, the County has approximately 254,543 acres of agricultural land, as of 2016. Of this, the County supports 30,619 acres of “Prime Farmland,” 9,593 acres of “Farmland of Statewide Importance,” 16,803 acres of “Unique Farmland,” 18,326 acres of “Farmland of Local Importance,” and 179,202 acres of “Grazing Land.” Based on the land use conversion table prepared by the DOC, between 2014 and 2016, 35 acres of the 30,654 acres of County’s Prime Farmland were converted to urban and built-up land. However, overall, Important Farmland in the County increased by 149 acres (DOC 2016). This is likely due to lands being converted to vineyards.

Agenda Item #6.2.

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The City contains approximately 956 acres of land designated as Prime Farmland, 284 acres of Farmland of Statewide Importance, 53 acres of Unique Farmland, and 33 acres of Farmland of Local Importance. There is no land designated as Grazing Land within the City (City of St.

Helena 2018). The Project site contains less than 6 acres of Prime Farmland and less than 1 acre of Farmland of Statewide Importance.

As described in Impact 3.2-1, the Proposed Project would not be considered to have a potential impact on agricultural resources. In addition, the Project site has long been designated for urban use. The St. Helena 1993 General Plan and also the current 2019 General Plan contains policies regarding the preservation of agricultural lands. For example, the City maintains large parcels for agricultural use and limits residential and commercial development within the Urban Limit Line to parcels already designated for such uses. The Proposed Project is not compromising the principles of urban-centered growth and agricultural preservation since the site has been designated for residential development and is located within the City limits. In addition, Countywide, conversion of agricultural lands in the County is decreasing. Therefore, the Proposed Project’s contribution to a cumulative effect is not considerable, and cumulative impacts would be less than significant.

Mitigation Measures
None required.

3.2.6 References
DOC (California Department of Conservation). 2017. Farmland Mapping and Monitoring Program. Accessed October 8, 2018. https://maps.conservation.ca.gov/DLRP/CIFF/.

DOC. 2016. Table A-21: Napa County 2014-2016 Land Use Conversion Table.

DOC. 1997. California Agricultural Land Evaluation and Site Assessment Model Instruction Manual.

USDA (United States Department of Agriculture). 2018. Web Soil Survey. Accessed August 6, 2018. Available at: https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx.

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 SCH# 2010042001. October 23, 2018.

City of St. Helena. 2018. City of St. Helena Zoning Districts. April 24, 2018.

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

Napa County. 2008. Napa County General Plan. June 3, 2008.

Agenda Item #6.2.

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3.3 AIR QUALITY

3.3.1 Introduction
This section of the Draft Environmental Impact Report presents potential air quality impacts of the proposed Hunter Subdivision Project (Proposed Project), which includes the environmental setting and existing air quality conditions, regulatory framework, potential short-term and longterm air quality impacts, and proposed measures to mitigate any identified significant impacts.

The analysis and findings are based on the air quality emissions modeling, which can be found in Appendix C.

No comments were received that raised concerns regarding air quality in response to the Notice of Preparation. A copy of the Notice of Preparation and comments received is included in Appendix A.

Information contained in this section is based on Proposed Project plans, the California Emissions Estimator Model (CalEEMod) to estimate Proposed Project emissions, the Bay Area Air Quality Management District (BAAQMD) California Environmental Quality Act Air Quality Guidelines (BAAQMD 2017a), and the Spare the Air: Cool The Climate – Final 2017 Clean Air Plan (BAAQMD 2017b). Other sources consulted are listed in Section 3.3.6, References.

3.3.2 Environmental Setting
The City of St. Helena (City) is located in the County of Napa (County), within the boundaries of the San Francisco Bay Area Air Basin (SFBAAB). The SFBAAB encompasses all of Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, and Santa Clara counties, and the southern portions of Solano and Sonoma counties.

Air pollutants are emitted by a variety of sources, including mobile sources (vehicles), area sources (fireplaces, consumer product use, architectural coatings, and landscape maintenance equipment), energy sources (natural gas combustion), and stationary sources (generators or other stationary equipment). Some air pollutants need to be examined at the local level, and others are predominately an issue at the regional level. For instance, ozone (O3) is formed in the atmosphere in the presence of sunlight by a series of chemical reactions involving oxides of nitrogen (NOx) and reactive organic gas (ROG, also termed volatile organic compounds [VOCs]). Because these reactions can occur many miles from the source, O3 is typically analyzed at the regional level (i.e., in the Air Basin) rather than the local level. On the other hand, air pollutants such as particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10), particulate matter with an aerodynamic diameter less than or equal to 2.5 microns (PM2.5), carbon monoxide (CO), and toxic air contaminants (TACs) are a potential concern in the immediate vicinity of the pollutant source because the pollutants are emitted Agenda Item #6.2.

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directly by or are formed close to the source. Therefore, the study area for emissions of PM10, PM2.5, CO, and TACs is the local area near the source, such as in the vicinity of the Project site, and the study area for regional pollutants such as NOx and ROGs is the entire SFBAAB.

Regional Climatology
Air quality is a function of the rate and location of pollutant emissions under the influence of meteorological conditions and topographic features that influence pollutant movement and dispersal. Atmospheric conditions such as wind speed, wind direction, atmospheric stability, and air temperature gradients interact with the physical features of the landscape to determine the movement and dispersal of air pollutants, and consequently affect air quality.

The climate of the SFBAAB is determined largely by a high-pressure system that is almost always present over the eastern Pacific Ocean off the west coast of North America. During winter, the Pacific high-pressure system shifts southward, allowing more storms to pass through the region. During summer and early fall, when few storms pass through the region, emissions generated within the Bay Area can combine with abundant sunshine under the restraining influences of topography and subsidence inversions to create conditions that are conducive to the formation of photochemical pollutants, such as O3, and secondary particulates, such as nitrates and sulfates.

The Project site is located in the Napa Valley climatological subregion. Specific topographic and climatological conditions for the subregion are described in the BAAQMD California Environmental Quality Act Air Quality Guidelines (BAAQMD 2017a). The Napa Valley is bordered by relatively high mountains. With an average ridge line height of about 2,000 feet, with some peaks approaching 3,000 to 4,000 feet, these mountains are effective barriers to the prevailing northwesterly winds. The Napa Valley is widest at its southern end and narrows in the north. During the day, the prevailing winds flow up valley from the south about half of the time. A strong up valley wind frequently develops during warm summer afternoons, drawing air in from the San Pablo Bay. Daytime winds sometimes flow down valley from the north. During the evening, especially in the winter, down valley winds often occur. Wind speeds are generally low, with almost 50% of the winds less than 4 miles per hour. Only 5% of the winds are between 16 and 18 miles per hour, representing strong summertime up valley winds and winter storms (BAAQMD 2017a).

The greatest precipitation in the City occurs from October to April, during which time the rainfall averages 2–7 inches per month. The average annual precipitation is 34.61 inches. The City has a mild climate with an annual average temperature of 75°F. The coolest months of the year are typically December through February, with an annual average low of 36°F. The warmest months are typically June through September, with an annual average high of 89°F. Prevailing wind direction in the City (as measured at the St. Helena station, approximately 0.42 miles southwest of the Project site) is from the west (WRCC 2019).

Agenda Item #6.2.

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The air pollution potential in the Napa Valley could be high if there were sufficient sources of air contaminants nearby. Summer and fall prevailing winds can transport O3 precursors northward from the Carquinez Strait Region to the Napa Valley, effectively trapping and concentrating the pollutants when stable conditions are present. The local upslope and downslope flows created by the surrounding mountains may also recirculate pollutants already present, contributing to buildup of air pollution. High O3 concentrations are a potential problem to sensitive crops such as wine grapes, as well as to human health. The high frequency of light winds and stable conditions during the late fall and winter contribute to the buildup of particulate matter from motor vehicles, agriculture, and woodburning in fireplaces and stoves.

Pollutants and Effects
Criteria Air Pollutants
Criteria air pollutants are defined as pollutants for which the federal and state governments have established ambient air quality standards, or criteria, for outdoor concentrations to protect public health. The federal and state standards have been set, with an adequate margin of safety, at levels above which concentrations could be harmful to human health and welfare. These standards are designed to protect the most sensitive persons from illness or discomfort.

Pollutants of concern include O3, nitrogen dioxide (NO2), CO, sulfur dioxide (SO2), PM10, PM2.5, and lead. These pollutants, as well as TACs, are discussed in the following paragraphs.1In California, sulfates, vinyl chloride, hydrogen sulfide, and visibility-reducing particles are also regulated as criteria air pollutants.

Ozone. O3 is a strong-smelling, pale blue, reactive, toxic chemical gas consisting of three oxygen atoms. It is a secondary pollutant formed in the atmosphere by a photochemical process involving the sun’s energy and O3 precursors. These precursors are mainly NOx and ROG. The maximum effects of precursor emissions on O3 concentrations usually occur several hours after they are emitted and many miles from the source. Meteorology and terrain play major roles in O3 formation, and ideal conditions occur during summer and early autumn on days with low wind speeds or stagnant air, warm temperatures, and cloudless skies. O3 exists in the upper atmosphere O3 layer (stratospheric ozone) and at Earth’s surface in the lower atmosphere (tropospheric ozone).2 The O3 that the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) regulate as a criteria air pollutant is produced close to the ground level, where people live, exercise, and breathe. Ground-level O3 is a harmful air pollutant that causes numerous adverse 1 The descriptions of the criteria air pollutants and associated health effects are based on the U.S.

Environmental Protection Agency’s “Criteria Air Pollutants” (EPA 2018a), the California Air Resources Board’s (CARB) “Glossary” (CARB 2019a), and CARB’s “Fact Sheet: Air Pollution Sources, Effects and Control” (CARB 2009).
2 The troposphere is the layer of Earth’s atmosphere nearest to the surface of Earth, extending outward approximately 5 miles at the poles and approximately 10 miles at the equator.

Agenda Item #6.2.

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health effects and is thus considered “bad” O3. Stratospheric, or “good,” O3 occurs naturally in the upper atmosphere, where it reduces the amount of ultraviolet light (i.e., solar radiation) entering the Earth’s atmosphere. Without the protection of the beneficial stratospheric O3 layer, plant and animal life would be seriously harmed.

O3 in the troposphere causes numerous adverse health effects; short-term exposures (lasting for a few hours) to O3 can result in breathing pattern changes, reduction of breathing capacity, increased susceptibility to infections, inflammation of the lung tissue, and some immunological changes (EPA 2013).

Inhalation of O3 causes inflammation and irritation of the tissues lining human airways, causing and worsening a variety of symptoms. Exposure to O3 can reduce the volume of air that the lungs breathe in and cause shortness of breath. O3 in sufficient doses increases the permeability of lung cells, rendering them more susceptible to toxins and microorganisms. The occurrence and severity of health effects from O3 exposure vary widely among individuals, even when the dose and the duration of exposure are the same. Research shows adults and children who spend more time outdoors participating in vigorous physical activities are at greater risk from the harmful health effects of O3 exposure. While there are relatively few studies of O3’s effects on children, the available studies show that children are no more or less likely to suffer harmful effects than adults. However, there are a number of reasons why children may be more susceptible to O3 and other pollutants. Children and teens spend nearly twice as much time outdoors and engaged in vigorous activities as adults. Children breathe more rapidly than adults and inhale more pollution per pound of their body weight than adults. Also, children are less likely than adults to notice their own symptoms and avoid harmful exposures. Further research may be able to better distinguish between health effects in children and adults. Children, adolescents and adults who exercise or work outdoors, where O3 concentrations are the highest, are at the greatest risk of harm from this pollutant (CARB 2019b).

Nitrogen Dioxide. NO2 is a brownish, highly reactive gas that is present in all urban atmospheres. The major mechanism for the formation of NO2 in the atmosphere is the oxidation of the primary air pollutant nitric oxide (NO), which is a colorless, odorless gas. NOx, which includes NO2 and NO, plays a major role, together with ROG, in the atmospheric reactions that produce O3. NOx is formed from fuel combustion under high temperature or pressure. In addition, NOx is an important precursor to acid rain and may affect both terrestrial and aquatic ecosystems. The two major emissions sources are transportation and stationary fuel combustion sources (such as electric utility and industrial boilers).

A large body of health science literature indicates that exposure to NO2 can induce adverse health effects. The strongest health evidence, and the health basis for the ambient air quality standards (AAQS) for NO2, results from controlled human exposure studies that show that NO2 Agenda Item #6.2.

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exposure can intensify responses to allergens in allergic asthmatics. In addition, a number of epidemiological studies have demonstrated associations between NO2 exposure and premature death, cardiopulmonary effects, decreased lung function growth in children, respiratory symptoms, emergency room visits for asthma, and intensified allergic responses. Infants and children are particularly at risk because they have disproportionately higher exposure to NO2 than adults due to their greater breathing rate for their body weight and their typically greater outdoor exposure duration. Several studies have shown that long-term NO2 exposure during childhood, the period of rapid lung growth, can lead to smaller lungs at maturity in children with higher compared to lower levels of exposure. In addition, children with asthma have a greater degree of airway responsiveness compared with adult asthmatics. In adults, the greatest risk is to people who have chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (CARB 2019c).

Carbon Monoxide. CO is a colorless, odorless gas formed by the incomplete combustion of hydrocarbon, or fossil fuels. CO is emitted almost exclusively from motor vehicles, power plants, refineries, industrial boilers, ships, aircraft, and trains. In urban areas, automobile exhaust accounts for the majority of CO emissions. CO is a nonreactive air pollutant that dissipates relatively quickly; therefore, ambient CO concentrations generally follow the spatial and temporal distributions of vehicular traffic. CO concentrations are influenced by local meteorological conditions—primarily wind speed, topography, and atmospheric stability. CO from motor vehicle exhaust can become locally concentrated when surface-based temperature inversions are combined with calm atmospheric conditions, which is a typical situation at dusk in urban areas from November to February. The highest levels of CO typically occur during the colder months of the year, when inversion conditions are more frequent.

CO is harmful because it binds to hemoglobin in the blood, reducing the ability of blood to carry oxygen. This interferes with oxygen delivery to the body’s organs. The most common effects of CO exposure are fatigue, headaches, confusion and reduced mental alertness, and lightheadedness, and dizziness due to inadequate oxygen delivery to the brain. For people with cardiovascular disease, short-term CO exposure can further reduce their body’s already compromised ability to respond to the increased oxygen demands of exercise, exertion, or stress. Inadequate oxygen delivery to the heart muscle leads to chest pain and decreased exercise tolerance. Unborn babies whose mothers experience high levels of CO exposure during pregnancy are at risk of adverse developmental effects. Unborn babies, infants, elderly people, and people with anemia or with a history of heart or respiratory disease are most likely to experience health effects with exposure to elevated levels of CO (CARB 2019d).

Sulfur Dioxide. SO2 is a colorless, pungent gas formed primarily from incomplete combustion of sulfur-containing fossil fuels. The main sources of SO2 are coal and oil used in power plants and industries; as such, the highest levels of SO2 are generally found near Agenda Item #6.2.

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large industrial complexes. In recent years, SO2 concentrations have been reduced by the increasingly stringent controls placed on stationary source emissions of SO2 and limits on the sulfur content of fuels.

Controlled human exposure and epidemiological studies show that children and adults with asthma are more likely to experience adverse responses with SO2 exposure, compared with the non-asthmatic population. Effects at levels near the one-hour standard are those of asthma exacerbation, including bronchoconstriction accompanied by symptoms of respiratory irritation such as wheezing, shortness of breath and chest tightness, especially during exercise or physical activity. Also, exposure at elevated levels of SO2 (above 1 parts per million [ppm]) results in increased incidence of pulmonary symptoms and disease, decreased pulmonary function, and increased risk of mortality. The elderly and people with cardiovascular disease or chronic lung disease (such as bronchitis or emphysema) are most likely to experience these adverse effects (CARB 2019e).

SO2 is of concern both because it is a direct respiratory irritant and because it contributes to the formation of sulfate and sulfuric acid in particulate matter (NRC 2005). People with asthma are of particular concern, both because they have increased baseline airflow resistance and because their SO2-induced increase in resistance is greater than in healthy people, and it increases with the severity of their asthma (NRC 2005). SO2 is thought to induce airway constriction via neural reflexes involving irritant receptors in the airways (NRC 2005).

Particulate Matter. Particulate matter pollution consists of very small liquid and solid particles floating in the air, which can include smoke, soot, dust, salts, acids, and metals. Particulate matter can form when gases emitted from industries and motor vehicles undergo chemical reactions in the atmosphere. PM2.5 and PM10 represent fractions of particulate matter. Coarse particulate matter (PM10) is about 1/7 the thickness of a human hair. Major sources of PM10 include crushing or grinding operations; dust stirred up by vehicles traveling on roads; woodburning stoves and fireplaces; dust from construction, landfills, and agriculture; wildfires and brush/waste burning; industrial sources; windblown dust from open lands; and atmospheric chemical and photochemical reactions. Fine particulate matter (PM2.5) is roughly 1/28 the diameter of a human hair. PM2.5 results from fuel combustion (e.g., from motor vehicles and power generation and industrial facilities), residential fireplaces, and woodstoves. In addition, PM2.5 can be formed in the atmosphere from gases such as sulfur oxides (SOx), NOx, and ROG.

PM2.5 and PM10 pose a greater health risk than larger-size particles. When inhaled, these tiny particles can penetrate the human respiratory system’s natural defenses and damage the respiratory tract. PM2.5 and PM10 can increase the number and severity of asthma attacks, cause or aggravate bronchitis and other lung diseases, and reduce the body’s ability to fight infections. Very small particles of substances such as lead, sulfates, and nitrates can cause Agenda Item #6.2.

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lung damage directly or be absorbed into the blood stream, causing damage elsewhere in the body. Additionally, these substances can transport adsorbed gases such as chlorides or ammonium into the lungs, also causing injury. PM10 tends to collect in the upper portion of the respiratory system, whereas PM2.5 is small enough to penetrate deeper into the lungs and damage lung tissue. Suspended particulates also produce haze and reduce regional visibility and damage and discolor surfaces on which they settle.

A number of adverse health effects have been associated with exposure to both PM2.5 and PM10. For PM2.5, short-term exposures (up to 24 hours duration) have been associated with premature mortality, increased hospital admissions for heart or lung causes, acute and chronic bronchitis, asthma attacks, emergency room visits, respiratory symptoms, and restricted activity days. These adverse health effects have been reported primarily in infants, children, and older adults with preexisting heart or lung diseases. In addition, of all of the common air pollutants, PM2.5 is associated with the greatest proportion of adverse health effects related to air pollution, both in the United States and world-wide based on the World Health Organization’s Global Burden of Disease Project. Short-term exposures to PM10 have been associated primarily with worsening of respiratory diseases, including asthma and chronic obstructive pulmonary disease, leading to hospitalization and emergency department visits. (CARB 2017).

Long-term (months to years) exposure to PM2.5 has been linked to premature death, particularly in people who have chronic heart or lung diseases, and reduced lung function growth in children. The effects of long-term exposure to PM10 are less clear, although several studies suggest a link between long-term PM10 exposure and respiratory mortality. The International Agency for Research on Cancer published a review in 2015 that concluded that particulate matter in outdoor air pollution causes lung cancer (CARB 2017).

Lead. Lead in the atmosphere occurs as particulate matter. Sources of lead include leaded gasoline; the manufacturing of batteries, paints, ink, ceramics, and ammunition; and secondary lead smelters. Prior to 1978, mobile emissions were the primary source of atmospheric lead. Between 1978 and 1987, the phase out of leaded gasoline reduced the overall inventory of airborne lead by nearly 95%. With the phase out of leaded gasoline, secondary lead smelters, battery recycling, and manufacturing facilities are becoming lead-emissions sources of greater concern.

Prolonged exposure to atmospheric lead poses a serious threat to human health. Health effects associated with exposure to lead include gastrointestinal disturbances, anemia, kidney disease, and, in severe cases, neuromuscular and neurological dysfunction. Of particular concern are low-level lead exposures during infancy and childhood. Such exposures are associated with decrements in neurobehavioral performance, including intelligence quotient performance, psychomotor performance, reaction time, and growth. Children are highly susceptible to the effects of lead.

Agenda Item #6.2.

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Sulfates. Sulfates are the fully oxidized form of sulfur, which typically occur in combination with metals or hydrogen ions. Sulfates are produced from reactions of SO2 in the atmosphere.

Sulfates can result in respiratory impairment, as well as reduced visibility.

Vinyl Chloride. Vinyl chloride is a colorless gas with a mild, sweet odor, which has been detected near landfills, sewage plants, and hazardous waste sites, due to the microbial breakdown of chlorinated solvents. Short-term exposure to high levels of vinyl chloride in air can cause nervous system effects, such as dizziness, drowsiness, and headaches. Long-term exposure through inhalation can cause liver damage, including liver cancer.

Hydrogen Sulfide. Hydrogen sulfide is a colorless and flammable gas that has a characteristic odor of rotten eggs. Sources of hydrogen sulfide include geothermal power plants, petroleum refineries, sewers, and sewage treatment plants. Exposure to hydrogen sulfide can result in nuisance odors, as well as headaches and breathing difficulties at higher concentrations.

Visibility-Reducing Particles. Visibility-reducing particles are any particles in the air that obstruct the range of visibility. Effects of reduced visibility can include obscuring the viewshed of natural scenery, reducing airport safety, and discouraging tourism. Sources of visibility-reducing particles are the same as for PM2.5 described above.

Reactive Organic Gases. Hydrocarbons are organic gases that are formed from hydrogen and carbon and sometimes other elements. Hydrocarbons that contribute to formation of O3 are referred to and regulated as ROG. Combustion engine exhaust, oil refineries, and fossil-fueled power plants are the sources of hydrocarbons. Other sources of hydrocarbons include evaporation from petroleum fuels, solvents, dry cleaning solutions, and paint.

The primary health effects of ROG result from the formation of O3 and its related health effects.

High levels of ROG in the atmosphere can interfere with oxygen intake by reducing the amount of available oxygen through displacement. Carcinogenic forms of hydrocarbons, such as benzene, are considered TACs. There are no separate health standards for ROG as a group.

Non-Criteria Air Pollutants
Toxic Air Contaminants. A substance is considered toxic if it has the potential to cause adverse health effects in humans, including increasing the risk of cancer upon exposure, or acute and/or chronic noncancer health effects. A toxic substance released into the air is considered a TAC.

TACs are identified by federal and state agencies based on a review of available scientific evidence. In the State of California, TACs are identified through a two-step process that was established in 1983 under the Toxic Air Contaminant Identification and Control Act. This twostep process of risk identification and risk management and reduction was designed to protect residents from the health effects of toxic substances in the air. In addition, the California Air Agenda Item #6.2.

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Toxics “Hot Spots” Information and Assessment Act, Assembly Bill (AB) 2588, was enacted by the Legislature in 1987 to address public concern over the release of TACs into the atmosphere.

The law requires facilities emitting toxic substances to provide local air pollution control districts with information that will allow an assessment of the air toxics problem, identification of air toxics emissions sources, location of resulting hotspots, notification of the public exposed to significant risk, and development of effective strategies to reduce potential risks to the public over 5 years.

Examples include certain aromatic and chlorinated hydrocarbons, certain metals, and asbestos.

TACs are generated by a number of sources, including stationary sources, such as dry cleaners, gas stations, combustion sources, and laboratories; mobile sources, such as automobiles; and area sources, such as landfills. Adverse health effects associated with exposure to TACs may include carcinogenic (i.e., cancer-causing) and noncarcinogenic effects.

Noncarcinogenic effects typically affect one or more target organ systems and may be experienced on either short-term (acute) or long-term (chronic) exposure to a given TAC.

Diesel Particulate Matter. Diesel particulate matter (DPM) is part of a complex mixture that makes up diesel exhaust. Diesel exhaust is composed of two phases, gas and particle, both of which contribute to health risks. More than 90% of DPM is less than 1 micrometer in diameter (about 1/70th the diameter of a human hair), and thus is a subset of PM2.5 (CARB 2016a). DPM is typically composed of carbon particles (“soot,” also called black carbon, or BC) and numerous organic compounds, including over 40 known cancer-causing organic substances. Examples of these chemicals include polycyclic aromatic hydrocarbons, benzene, formaldehyde, acetaldehyde, acrolein, and 1,3-butadiene (CARB 2016a). The CARB classified “particulate emissions from diesel-fueled engines” (i.e., DPM; 17 CCR 93000) as a TAC in August 1998.

DPM is emitted from a broad range of diesel engines: on-road diesel engines of trucks, buses, and cars, and off-road diesel engines including locomotives, marine vessels, and heavy-duty construction equipment, among others. Approximately 70% of all airborne cancer risk in California is associated with DPM (CARB 2000). Because it is part of PM2.5, DPM also contributes to the same non-cancer health effects as PM2.5 exposure. These effects include premature death; hospitalizations and emergency department visits for exacerbated chronic heart and lung disease, including asthma; increased respiratory symptoms; and decreased lung function in children. Several studies suggest that exposure to DPM may also facilitate development of new allergies (CARB 2016b). Those most vulnerable to non-cancer health effects are children whose lungs are still developing and the elderly who often have chronic health problems.

Odorous Compounds. Odors are generally regarded as an annoyance rather than a health hazard. Manifestations of a person’s reaction to odors can range from psychological (e.g., irritation, anger, or anxiety) to physiological (e.g., circulatory and respiratory effects, nausea, vomiting, and headache). The ability to detect odors varies considerably among the population Agenda Item #6.2.

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and overall is quite subjective. People may have different reactions to the same odor. An odor that is offensive to one person may be perfectly acceptable to another (e.g., coffee roaster). An unfamiliar odor is more easily detected and is more likely to cause complaints than a familiar one. Known as odor fatigue, a person can become desensitized to almost any odor, and recognition may only occur with an alteration in the intensity. The occurrence and severity of odor impacts depend on the nature, frequency, and intensity of the source; wind speed and direction; and the sensitivity of receptors.

Sensitive Receptors
Some land uses are considered more sensitive to changes in air quality than others, depending on the population groups and the activities involved. People most likely to be affected by air pollution include children, the elderly, athletes, and people with cardiovascular and chronic respiratory diseases. Facilities and structures where these air pollution-sensitive people live or spend considerable amounts of time are known as sensitive receptors. Land uses where air pollution–sensitive individuals are most likely to spend time include schools and schoolyards, parks and playgrounds, daycare centers, nursing homes, hospitals, and residential communities (sensitive sites or sensitive land uses) (CARB 2005). Sensitive receptors are groups of individuals, including children, the elderly, the acutely ill, and the chronically ill, that may be more susceptible to health risks due to chemical exposure, and sensitive-receptor population groups are likely to be located at hospitals, medical clinics, schools, playgrounds, childcare centers, residences, and retirement homes (BAAQMD 2017a). The closest sensitive receptors are single-family residences located approximately 20 feet east of the Project site.

Regional and Local Air Quality Conditions
San Francisco Bay Area Air Basin Designation
An area is designated in attainment when it is in compliance with the National Ambient Air Quality Standards (NAAQS) and/or California Ambient Air Quality Standards (CAAQS). These standards are set by the EPA or CARB for the maximum level of a given air pollutant that can exist in the outdoor air without unacceptable effects on human health or the public welfare.

The primary pollutants of concern in SFBAAB are ozone, PM10, and PM2.5 because SFBAAB is designated nonattainment for these pollutants by EPA and CARB. The SFBAAB is designated as nonattainment for the 8-hour NAAQS for O3 and is also nonattainment for PM2.5. The SFBAAB is designated as attainment for all other criteria pollutants under the NAAQS. The SFBAAB is currently designated as nonattainment for O3, both 1-hour and 8-hour, PM10 and PM2.5 under the CAAQS.

Table 3.3-1 depicts the current attainment status within the air basin with respect to the NAAQS and CAAQS, as well as the attainment classifications for criteria pollutants.

Agenda Item #6.2.

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Table 3.3-1
State and Federal Ambient Air Quality Standards and Attainment Status Pollutant
Averaging
Time
California Standardsa National Standardsb
Standard
Attainment
Status Standard
Attainment
Status
Ozone (O3) 1 hour 0.09 ppm N NA NA
8 hour 0.07 ppm N 0.070 ppm N/Marginalc
Carbon Monoxide (CO) 1 hour 20 ppm A 35 ppm A
8 hour 9 ppm A 9 ppm A
Nitrogen Dioxide (NO2) 1 hour 0.18 ppm A 0.100 ppm U
Annual 0.030 ppm NA 0.053 ppm A
Sulfur Dioxide (SO2) 1 hour 0.25 ppm A 0.075 ppm A
24 hour 0.04 ppm A 0.14 ppm A
Annual NA NA 0.03 ppm A
Particulate Matter (PM10) 24 hour 50 µg/m3 N 150 µg/m3 U Annual 20 µg/m3 N NA NA
Fine Particulate Matter (PM2.5) 24 hour NA NA 35 µg/m3 N d
Annual 12 µg/m3 N 12 µg/m3 U/Ae
Sulfates 24 hour 25 µg/m3 A NA NA
Lead 30 day 1.5 µg/m3 NA NA A
Cal. Quarter NA NA 1.5 µg/m3 A
Rolling 3-
Month
Average
NA NA 0.15 µg/m3 U/A
Hydrogen Sulfide 1 hour 0.03 ppm U NA NA
Visibility-Reducing Particles 8 hour See Note “f” U NA NA Source: BAAQMD 2017c; CARB 2018 (state); EPA 2018b (federal).

Notes: g/m3 = micrograms per cubic meter; mg/m3= milligrams per cubic meter; PM10 = particulate matter with an aerodynamic diameter less than or equal to 10 microns; PM2.5 = particulate matter with an aerodynamic diameter less than or equal to 2.5 microns; ppm = parts per million by volume; A = Attainment; N = Nonattainment; U = Unclassified; NA = Not Applicable (no applicable standard) a California standards for O3, CO, SO2 (1-hour and 24-hour), NO2, suspended particulate matter (PM10, PM2.5), and visibility-reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded. If the standard is for a 1-hour, 8-hour or 24-hour average (i.e., all standards except for lead and the PM10 annual standard), then some measurements can be excluded. In particular, measurements are excluded that CARB determines would occur less than once per year on the average. b National standards shown are the “primary standards” designed to protect public health. NAAQS (other than O3, NO2, SO2, particulate matter, and those based on annual averages or annual arithmetic mean) are not to be exceeded more than once per year. The O3 standard is attained when the fourth highest 8-hour concentration measured at each site in a year, averaged over 3 years, is equal to or less than the standard. For PM10, the 24-hour standard is attained when the expected number of days per calendar year with a 24-hour average concentration above 150 µg/m3is equal to or less than 1. For PM2.5, the 24-hour standard is attained when 98% of the daily concentrations, averaged over 3 years, are equal to or less than the standard. c On October 1, 2015, the national 8-hour O3 primary and secondary standards were lowered from 0.075 to 0.070 ppm. An area will meet the standard if the fourth-highest maximum daily 8-hour ozone concentration per year, averaged over three years, is equal to or less than 0.070 ppm. EPA will make recommendations on attainment designations by October 1, 2016, and issue final designations October 1, 2017.

Nonattainment areas will have until 2020 to late 2037 to meet the health standard, with attainment dates varying based on the O3 level in the area.
d On January 9, 2013, the EPA issued a final rule to determine that the Bay Area attains the 24-hour PM2.5 national standard. This EPA rule suspends key State Implementation Plan requirements as long as monitoring data continues to show that the Bay Area attains the standard.

Agenda Item #6.2.

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Despite this EPA action, the Bay Area will continue to be designated as “nonattainment” for the national 24-hour PM2.5 standard until such time as the BAAQMD submits a “redesignation request” and a “maintenance plan” to EPA, and EPA approves the proposed redesignation. e
In December 2012, the EPA strengthened the annual PM2.5 NAAQS from 15.0 to 12.0 μg/m3. In December 2014, EPA issued final area designations for the 2012 primary annual PM2.5 NAAQS. Areas designated “unclassifiable/attainment” must continue to take steps to prevent their air quality from deteriorating to unhealthy levels. The effective date of this standard is April 15, 2015. f Statewide visibility reducing particle standard (except Lake Tahoe Air Basin): Particles in sufficient amount to produce an extinction coefficient of 0.23 per kilometer when the relative humidity is less than 70%. This standard is intended to limit the frequency and severity of visibility impairment due to regional haze and is equivalent to a 10-mile nominal visual range.

Local Ambient Air Quality
CARB, air districts, and other agencies monitor ambient air quality at approximately 250 air quality monitoring stations across the state. Air quality monitoring stations usually measure pollutant concentrations 10 feet above ground level; therefore, air quality is often referred to in terms of ground-level concentrations. The Jefferson Avenue monitoring station, located at 2552 Jefferson Avenue, Napa, CA 94558, is the nearest air quality monitoring station to the Project site, located approximately 16.5 miles southeast from the Project site. The most up-to-date air quality data from 2016 to 2018 for O3, NO2, CO, PM10, and PM2.5 from the Jefferson Avenue monitoring station are provided in Table 3.3-2. The data collected at this station is considered generally representative of the air quality experienced in the Project vicinity. The number of days exceeding the ambient air quality standards is also shown in Table 3.3-2.

Table 3.3-2
Local Ambient Air Quality Data
Monitoring
Station Unit
Averaging
Time
Agency/
Method
Ambient
Air
Quality
Standard
Measured Concentration by
Year
Exceedances by
Year
2016 2017 2018 2016 2017 2018
Ozone (O3)
NapaJefferson
Avenue
ppm Maximum 1-
hour
concentration
State 0.09 0.080 0.098 0.047 0 1 0
ppm Maximum 8-
hour
concentration
State 0.070 0.068 0.084 0.043 0 2 0
Federal 0.070 0.067 0.084 0.042 0 2 0
Nitrogen Dioxide (NO2)
NapaJefferson
Avenue
ppm Maximum 1-
hour
concentration
State 0.18 0.039 0.052 0.039 0 0 0
Federal 0.100 0.039 0.0526 0.039 0 0 0
ppm Annual
concentration
State 0.030 0.007 0.007 ND — — —
Federal 0.053 — — — — — —
Agenda Item #6.2.

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Table 3.3-2
Local Ambient Air Quality Data
Monitoring
Station Unit
Averaging
Time
Agency/
Method
Ambient
Air
Quality
Standard
Measured Concentration by
Year
Exceedances by
Year
2016 2017 2018 2016 2017 2018
Carbon Monoxide (CO)
NapaJefferson
Avenue
ppm Maximum 1-
hour
concentration
State 20 — — — — — —
Federal 35 2.2 5.6 1.6 0 0 0
ppm Maximum 8-
hour
concentration
State 9.0 — — — — — —
Federal 9 1.5 4.7 1.1 0 0 0
Coarse Particulate Matter (PM10)
a
NapaJefferson
Avenue
g/m3 Maximum 24-
hour
concentration
State 50 33.0 ND ND ND
(0)
ND
(0)
ND
(0)
Federal 150 32.2 ND ND ND
(0)
ND
(0)
ND
(0)
g/m3 Annual
concentration
State 20 ND ND ND — — —
Fine Particulate Matter (PM2.5)
a
NapaJefferson
Avenue
g/m3 Maximum 24-
hour
concentration
Federal 35 24.3 199.1 30.2 0.0
(0)

13.3 (13)
ND
(0)
g/m3 Annual
concentration
State 12 24.3 199.1 30.2 — — —
Federal 12.0 8.5 13.7 ND — — —
Sources: CARB 2019f; EPA 2019.

Notes: — = data not available; g/m3 = micrograms per cubic meter; ND = insufficient data available to determine the value; ppm = parts per million Data taken from CARB iADAM (http://www.arb.ca.gov/adam) and EPA AirData (http://www.epa.gov/airdata/) represent the highest concentrations experienced over a given year.

Exceedances of federal and state standards are only shown for O3 and particulate matter. Daily exceedances for particulate matter are estimated days because PM10 and PM2.5 are not monitored daily. All other criteria pollutants did not exceed federal or state standards during the years shown. There is no federal standard for 1-hour ozone, annual PM10, nor is there a state 24-hour standard for PM2.5.

Napa-Jefferson Avenue Monitoring Station is located at 2552 Jefferson Avenue, Sebastopol, California 94558. a Measurements of PM10 and PM2.5 are usually collected every 6 days and every 1 to 3 days, respectively. Number of days exceeding the standards is a mathematical estimate of the number of days concentrations would have been greater than the level of the standard had each day been monitored. The numbers in parentheses are the measured number of samples that exceeded the standard.

3.3.3 Regulatory Setting
The following federal, state and regulations pertaining to air quality would apply to the Proposed Project.

Agenda Item #6.2.

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Federal Regulations
Clean Air Act
The federal Clean Air Act, passed in 1970 and last amended in 1990, forms the basis for the national air pollution control effort. The EPA is responsible for implementing most aspects of the Clean Air Act, including setting NAAQS for major air pollutants; setting hazardous air pollutant (HAP) standards; approving state attainment plans; setting motor vehicle emission standards; issuing stationary source emission standards and permits; and establishing acid rain control measures, stratospheric O3 protection measures, and enforcement provisions. Under the Clean Air Act, NAAQS are established for the following criteria pollutants: O3, CO, NO2, SO2, PM10, PM2.5, and lead.

The NAAQS describe acceptable air quality conditions designed to protect the health and welfare of the citizens of the nation. The NAAQS (other than for O3, NO2, SO2, PM10, PM2.5, and those based on annual averages or arithmetic mean) are not to be exceeded more than once per year. NAAQS for O3, NO2, SO2, PM10, and PM2.5 are based on statistical calculations over 1- to 3-year periods, depending on the pollutant. The Clean Air Act requires the EPA to reassess the NAAQS at least every 5 years to determine whether adopted standards are adequate to protect public health based on current scientific evidence. States with areas that exceed the NAAQS must prepare a State Implementation Plan that demonstrates how those areas will attain the standards within mandated timeframes. Each State Implementation Plan is developed through a public process, formally adopted by the state, and submitted by the Governor’s designee to the U.S. EPA. The Clean Air Act requires the U.S. EPA to review each plan and any plan revisions and to approve the plan or plan revisions if consistent with the Clean Air Act.

The 1977 federal Clean Air Act amendments required the EPA to identify National Emission Standards for Hazardous Air Pollutants to protect public health and welfare. HAPs include certain VOCs, pesticides, herbicides, and radionuclides that present a tangible hazard, based on scientific studies of exposure to humans and other mammals. Under the 1990 federal Clean Air Act amendments, which expanded the control program for HAPs, 189 substances and chemical families were identified as HAPs.

State Regulations
California Clean Air Act
The California Clean Air Act requires all areas of the state to achieve and maintain the CAAQS by the earliest practicable date. In California, the task of air quality management and regulation has been legislatively granted to CARB, with subsidiary responsibilities assigned to air quality management districts and air pollution control districts at the regional and county levels. CARB, Agenda Item #6.2.

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which became part of the California Environmental Protection Agency in 1991, is responsible for ensuring implementation of the California Clean Air Act of 1988, responding to the federal Clean Air Act, and regulating emissions from motor vehicles and consumer products.

CARB has established CAAQS, which are generally more restrictive than the NAAQS. The CAAQS describe adverse conditions; that is, pollution levels must be below these standards before a basin can attain the standard. Air quality is considered “in attainment” if pollutant levels are continuously below the CAAQS and violate the standards no more than once each year.

The CAAQS for O3, CO, SO2 (1-hour and 24-hour), NO2, PM10, and PM2.5 and visibility-reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded.

The NAAQS and CAAQS air quality standards are presented in Table 3.3-3.

Table 3.3-3
Ambient Air Quality Standards
Pollutant Averaging Time
California Standardsa National Standardsb
Concentrationc Primaryc,d Secondaryc,e
O3 1 hour 0.09 ppm (180 g/m3
) — Same as Primary
Standardf
8 hours 0.070 ppm (137 g/m3
) 0.070 ppm (137 g/m3)
f
NO2
g 1 hour 0.18 ppm (339 g/m3
) 0.100 ppm (188 g/m3) Same as Primary
Standard annual arithmetic
mean

0.030 ppm (57 g/m3) 0.053 ppm (100 g/m3)
CO 1 hour 20 ppm (23 mg/m3) 35 ppm (40 mg/m3) None
8 hours 9.0 ppm (10 mg/m3) 9 ppm (10 mg/m3)
SO2
h 1 hour 0.25 ppm (655 g/m3
) 0.075 ppm (196 g/m3) —
3 hours — — 0.5 ppm (1,300
g/m3)
24 hours 0.04 ppm (105 g/m3
) 0.14 ppm (for certain
areas)g
—
annual — 0.030 ppm (for certain
areas)g
—
PM10i 24 hours 50 g/m3 150 g/m3 Same as Primary
Standard annual arithmetic
mean
20 g/m3 —
PM2.5i 24 hours — 35 g/m3 Same as Primary
Standard
annual arithmetic
mean
12 g/m3 12.0 g/m3 15.0 g/m3
Leadj,k 30-day average 1.5 g/m3 — —
calendar quarter — 1.5 g/m3 (for certain
areas)k
Same as Primary
Standard
rolling 3-month
average
— 0.15 g/m3
Hydrogen
sulfide
1 hour 0.03 ppm (42 µg/m3) — —
Agenda Item #6.2.

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Table 3.3-3
Ambient Air Quality Standards
Pollutant Averaging Time
California Standardsa National Standardsb
Concentrationc Primaryc,d Secondaryc,e
Vinyl
chloridej
24 hours 0.01 ppm (26 µg/m3) — —
Sulfates 24 hours 25 µg/m3 — —
Visibilityreducing
particles
8 hour (10:00 a.m. to
6:00 p.m. PST)
Insufficient amount to
produce an extinction
coefficient of 0.23 per
kilometer due to the number
of particles when the relative
humidity is less than 70%
— —
Source: CARB 2016c.

Notes: g/m3 = micrograms per cubic meter; mg/m3= milligrams per cubic meter; ppm = parts per million by volume; O3 = ozone; NO2 = nitrogen dioxide; CO = carbon monoxide; SO2 = sulfur dioxide; PM10 = particulate matter with an aerodynamic diameter less than or equal to 10 microns; PM2.5 = particulate matter with an aerodynamic diameter less than or equal to 2.5 microns. a California standards for O3, CO, SO2 (1-hour and 24-hour), NO2, suspended particulate matter (PM10, PM2.5), and visibility-reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded. CAAQS are listed in the Table of Standards in Section 70200 of Title 17 of the California Code of Regulations. b National standards (other than O3, NO2, SO2, particulate matter, and those based on annual averages or annual arithmetic mean) are not to be exceeded more than once per year. The O3 standard is attained when the fourth highest 8-hour concentration measured at each site in a year, averaged over 3 years, is equal to or less than the standard. For PM10, the 24-hour standard is attained when the expected number of days per calendar year with a 24-hour average concentration above 150 µg/m3is equal to or less than 1. For PM2.5, the 24-hour standard is attained when 98% of the daily concentrations, averaged over 3 years, are equal to or less than the standard. c Concentration expressed first in units in which it was promulgated. Equivalent units given in parentheses are based on a reference temperature of 25°C and a reference pressure of 760 torr. Most measurements of air quality are to be corrected to a reference temperature of 25°C and a reference pressure of 760 torr; ppm in this table refers to ppm by volume, or micromoles of pollutant per mole of gas. d National Primary Standards: The levels of air quality necessary, with an adequate margin of safety, to protect the public health. e National Secondary Standards: The levels of air quality necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant.
ff On October 1, 2015, the national 8-hour O3 primary and secondary standards were lowered from 0.075 to 0.070 ppm. g To attain the national 1-hour standard, the 3-year average of the annual 98th percentile of the 1-hour daily maximum concentrations at each site must not exceed 100 parts per billion (ppb). Note that the national 1-hour standard is in units of ppb. California standards are in units of ppm. To directly compare the national 1-hour standard to the California standards, the units can be converted from ppb to ppm. In this case, the national standard of 100 ppb is identical to 0.100 ppm. h On June 2, 2010, a new 1-hour SO2 standard was established, and the existing 24-hour and annual primary standards were revoked. To attain the national 1-hour standard, the 3-year average of the annual 99th percentile of the 1-hour daily maximum concentrations at each site must not exceed 75 ppb. The 1971 SO2 national standards (24-hour and annual) remain in effect until 1 year after an area is designated for the 2010 standard, except that in areas designated nonattainment of the 1971 standards, the 1971 standards remain in effect until implementation plans to attain or maintain the 2010 standards are approved. i On December 14, 2012, the national annual PM2.5 primary standard was lowered from 15 g/m3 to 12.0 g/m3. The existing national 24-
hour PM2.5 standards (primary and secondary) were retained at 35 g/m3, as was the annual secondary standard of 15 μg/m3. The existing 24-hour PM10 standards (primary and secondary) of 150 g/m3 were also retained. The form of the annual primary and secondary standards is the annual mean averaged over 3 years.
j CARB has identified lead and vinyl chloride as TACs with no threshold level of exposure for adverse health effects determined. These actions allow for the implementation of control measures at levels below the ambient concentrations specified for these pollutants. k The national standard for lead was revised on October 15, 2008, to a rolling 3-month average. The 1978 lead standard (1.5 μg/m3 as a quarterly average) remains in effect until 1 year after an area is designated for the 2008 standard, except that in areas designated nonattainment for the 1978 standard, the 1978 standard remains in effect until implementation plans to attain or maintain the 2008 standard are approved.

Agenda Item #6.2.

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Toxic Air Contaminants
The state Air Toxics Program was established in 1983 under AB 1807 (Tanner). The California TAC list identifies more than 700 pollutants, a subset of which have carcinogenic and noncarcinogenic toxicity criteria established pursuant to the California Health and Safety Code.

In accordance with AB 2728, the state list includes the (federal) HAPs. The Air Toxics “Hot Spots” Information and Assessment Act of 1987 (AB 2588) was enacted by the legislature in 1987 to address public concern over the release of TACs into the atmosphere. AB 2588 law requires facilities emitting toxic substances to provide local air pollution control districts with information that will allow an assessment of the air toxics problem, identification of air toxics emissions sources, location of resulting hotspots, notification of the public exposed to significant risk, and development of effective strategies to reduce potential risks to the public over 5 years.

TAC emissions from individual facilities are quantified and prioritized. “High-priority” facilities are required to perform a health risk assessment, and if specific thresholds are exceeded, are required to communicate the results to the public in the form of notices and public meetings.

In 2000, CARB approved a comprehensive Diesel Risk Reduction Plan to reduce diesel emissions from both new and existing diesel-fueled vehicles and engines (CARB 2000). The regulation is anticipated to result in an 80% decrease in statewide diesel health risk in 2020 compared with the diesel risk in 2000. Additional regulations apply to new trucks and diesel fuel, including the On-Road Heavy Duty Diesel Vehicle (In-Use) Regulation (CARB 2014), On-Road Heavy Duty (New) Vehicle Program (CARB 2005b), In-Use Off-Road Diesel Vehicle Regulation (CARB 2011), and New Off-Road Compression-Ignition (Diesel) Engines and Equipment program (CARB 2008). These regulations and programs have timetables to which manufacturers must comply and existing operators must upgrade their diesel-powered equipment. There are several Airborne Toxic Control Measures that reduce diesel emissions, including In-Use Off-Road Diesel-Fueled Fleets (13 CCR 2449 et seq.) and In-Use On-Road Diesel-Fueled Vehicles (13 CCR 2025).

California Health and Safety Code Section 41700
This section of the Health and Safety Code states that a person shall not discharge from any source whatsoever quantities of air contaminants or other material that cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public; or that endanger the comfort, repose, health, or safety of any of those persons or the public; or that cause, or have a natural tendency to cause, injury or damage to business or property. This section also applies to sources of objectionable odors.

Agenda Item #6.2.

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September 2021 3.3-18
Local Regulations
Bay Area Air Quality Management District
The BAAQMD is the regional agency responsible for the regulation and enforcement of federal, state, and local air pollution control regulations in the SFBAAB, where the Project site is located.

The clean air strategy of the BAAQMD includes the preparation of plans for the attainment of ambient air quality standards, adoption and enforcement of rules and regulations concerning sources of air pollution, issuance of permits for stationary sources of air pollution, inspection of stationary sources of air pollution and response to citizen complaints, monitoring of ambient air quality and meteorological conditions, and implementation of programs and regulations required by the federal and California Clean Air Acts.

On April 19, 2017, the BAAQMD adopted the Spare the Air: Cool The Climate Final 2017 Clean Air Plan (2017 Clean Air Plan) (BAAQMD 2017c). The 2017 Clean Air Plan provides a regional strategy to protect public health and protect the climate. To protect public health, the 2017 Clean Air Plan includes all feasible measures to reduce emissions of O3 precursors (ROG and NOx) and reduce O3 transport to neighboring air basins. In addition, the 2017 Clean Air Plan builds on BAAQMD efforts to reduce PM2.5 and TACs. To protect the climate, the 2017 Clean Air Plan defines a vision for transitioning the region to a post-carbon economy needed to achieve ambitious greenhouse gas (GHG) reduction targets for 2030 and 2050, and provides a regional climate protection strategy that will put the Bay Area on a pathway to achieve those GHG reduction targets.

BAAQMD establishes and administers a program of rules and regulations to attain and maintain state and national air quality standards and regulations related to TACs. The rules and regulations that may apply to the Proposed Project include the following:
• Regulation 2, Rule 1 – Permits. This rule specifies the requirements for authorities to construct and permits.
• Regulation 6, Rule 1 – General Requirements. This rule limits the quantity of particulate matter in the atmosphere through the establishment of limitations on emission rates, concentration, visible emissions, and opacity.
• Regulation 6, Rule 3 – Wood-Burning Devices. This rule limits the emissions of particulate matter and visible emissions from wood-burning devices used for primary heat, supplemental heat or ambiance.
• Regulation 6, Rule 6 – Prohibition of Trackout. This rule addresses fugitive road dust emissions associated with trackout of solid materials onto paved public roads outside the boundaries of large bulk material sites, large construction sites and large disturbed surface sites (sites of 1-acre or more), and large disturbed surface sites.

Agenda Item #6.2.

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• Regulation 8, Rule 1 – General Provisions. This rule limits the emission of organic compounds into the atmosphere.
• Regulation 8, Rule 3 – Architectural Coatings. This rule limits the quantity of volatile organic compounds in architectural coatings supplied, sold, offered for sale, applied, solicited for application, or manufactured for use within the BAAQMD. • Regulation 8, Rule 15 – Emulsified and Liquid Asphalts. This rule limits the emissions of VOCs caused by the use of emulsified and liquid asphalt in paving materials and paving and maintenance operations.

City of St. Helena 1993 General Plan
The Land Use and Growth Management and Public Health and Safety Elements of the City of St. Helena 1993 General Plan (City of St. Helena 1993) provides policies regarding air quality, including the following:

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

Policy 8.2.3: Urge and support 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 (CMP) as feasible:
• The Napa County CMP recommends a number of land use-based measures to manage traffic congestion, and thereby reduce auto emissions. The recommendations are organized into two categories:
o Destination-based Strategies: 1) Concentrate major work locations in nodes or employment centers; 2) Encourage mixed-based development that allows people to combine or avoid vehicle trips; and 3) Require site design features that encourage transit use.
o Origin-based Strategies: 1) Match housing opportunities to income levels; 2) Provide housing opportunities near employment centers; and 3) Require design features that encourage transit use.

Policy 8.2.4: Consider cumulative air quality impacts from proposed developments and promote balanced land use development.

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

Agenda Item #6.2.

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Policy 8.2.6: Minimize local adverse air quality impacts related to construction by requiring dust abatement procedures for local projects.

Policy 8.2.8: Encourage the use of EPA-approved wood stoves or fireplace inserts, rather than fireplaces, as a means of reducing emissions into the air.

City of St. Helena 2019 General Plan (“General Plan Update 2040”) The Land Use and Growth Management and Public Health and Safety Elements of the City of St. Helena 2019 General Plan (City of St. Helena 2019) provides policies regarding air quality, including the following:

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

Policy PS1.1: Achieve and maintain clean, healthy air for the residents of St. Helena to preserve environmental quality and community health.

Policy PS1.2: Support regional efforts to achieve and maintain state ambient concentration standards to protect public health, reduce adverse industrial plant effects, and enhance the visual environment. In particular, provide local support for implementation of policies and measures set forth in the Napa County Congestion Management Program.

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 PS1.4: Promote an optimized land use development pattern that minimizes cumulative air quality impacts from proposed developments.

3.3.4 Impacts
Methods of Analysis
Construction
Emissions from the construction phase of the Proposed Project were estimated using CalEEMod Version 2016.3.2 (CAPCOA 2017). CalEEMod is a statewide computer model developed in cooperation with air districts throughout the state to quantify criteria air pollutant emissions associated with the construction and operational activities from a variety of land use projects, such as residential, commercial, and industrial facilities.

Agenda Item #6.2.

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For the purposes of modeling, a 6-year build out was assumed. Under a 6-year buildout it is assumed site grading and all backbone infrastructure would be completed in the first Phase.

Construction scenario assumptions, including phasing, equipment mix, and vehicle trips, were based on information provided by the applicant and CalEEMod generated default values.

Complete detailed construction assumptions are included in Appendix C. Implementation of the Proposed Project would include construction of 87 residential units including 51 single-family residences, 11 accessory dwelling units (ADUs), and 25 multi-family units.

Buildout under the 6-year buildout scenario assumes no more than 9 single-family residences would be constructed each year and the 25 affordable housing units would be constructed by the third year. All of the other assumptions related to grading, site preparation and construction equipment would not change under this buildout scenario, only the timing when residences could be constructed.

As described in Chapter 2, Project Description, the Proposed Project would grade the 16.9-acre site.

Soil balance would occur within each subset area and hauling would not be required between subset areas.3 Balancing activities are anticipated to be performed through the use of off-road construction equipment (e.g., excavators, graders, dozers, and scrapers). The Proposed Project schedule was based on information provided by the Proposed Project applicant and illustrates a realistic buildout assuming the Tentative Subdivision Map is approved sometime in 2021. Table 3.3- 4 provides the phasing assumptions under the 6-year Buildout.

Table 3.3-4
Construction Phasing Assumptions – 6-Year Buildout1
Proposed Project Construction Phase Construction Start Month/Year Construction End Month/Year Phase 1
Site Preparation 03/20/2023 03/31/2023
Grading 04/01/2023 04/28/2023
Paving 04/29/2023 05/26/2023
Building Construction 05/27/2023 12/22/2023
Architectural Coating 12/23/2023 01/19/2024
Phase 2
Building Construction 03/18/2024 10/11/2024
Architectural Coating 10/12/2024 11/08/2024
3 The estimated net grading quantity, as provided by the Proposed Project applicant, is approximately 24,321 cubic yards of fill to replace the 10,202 cubic yards of cut. This quantity does not include the spoils from the joint trench, roadways, curb and gutter, or foundations. It is the applicant’s intent to balance the soils on site and not require the export or import of soils. Importing of some material, such as base rock, sand, and peat gravel that is used in the joint trenches, building foundations, and roadways would be required.

Agenda Item #6.2.

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Table 3.3-4
Construction Phasing Assumptions – 6-Year Buildout1
Proposed Project Construction Phase Construction Start Month/Year Construction End Month/Year Phase 3
Building Construction 03/17/2025 01/30/2026
Architectural Coating 01/31/2026 02/25/2026
Phase 4
Building Construction 03/23/2026 10/16/2026
Architectural Coating 10/17/2026 11/11/2026
Phase 5
Building Construction 03/22/2027 10/15/2027
Architectural Coating 10/16/2027 11/10/2027
Phase 6
Building Construction 03/20/2028 10/13/2028
Architectural Coating 10/14/2028 11/08/2028
Source: Appendix C.

Notes: See Appendix C for details.

1. Phase 1 = grading, site clearing, backbone infrastructure, 9 residential units and 2 accessory dwelling units (ADUs); Phase 2 = 9 residential units, 2 ADUs; Phase 3 = 9 residential units, 2 ADUs, 25 affordable units; Phase 4 = 9 residential units, 2 ADUs, Phase 5 = 9 residential units and 2 ADUs; Phase 6 = 9 residential units and 1 ADU.

The construction equipment mix used for estimating the construction emissions of the Proposed Project is shown in Table 3.3-5. Notably, because detailed specific information regarding the construction equipment fleet is unknown at the time of analysis, the analysis is based on the default construction equipment fleet provided by CalEEMod. The construction tabs within CalEEMod contain default information that was obtained from a survey of construction sites conducted by the South Coast Air Quality Management District (CAPCOA 2017). The construction survey data is grouped by construction phase and lot acreage. The default construction equipment list and phase length data were determined to be the most appropriate for the size and types surveyed.

Agenda Item #6.2.

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Table 3.3-5
Construction Scenario Assumptions
Construction
Phase
One-way Vehicle Trips Equipment
Average
Daily
Worker
Trips
Average Daily
Vendor Truck
Trips
Total Haul
Truck Trips Equipment Type Quantity
Usage
Hours
Site Preparation 18 0 0 Rubber Tired Dozers 3 8
Tractors/Loaders/Backhoes 4 8
Grading 20 2 0 Excavators 2 8
Graders 1 8
Rubber Tired Dozers 1 8
Scrapers 2 8
Tractors/Loaders/Backhoes 2 8
Paving 15 0 0 Pavers 2 8
Paving Equipment 2 8
Rollers 2 8
Building
Construction
55 11 0 Cranes 1 7
Forklifts 3 8
Generator Sets 1 8
Tractors/Loaders/Backhoes 3 7
Trenchers 1 8
Welders 1 8
Architectural
Coating
11 0 0 Air Compressors 1 6
Source: Appendix C.

For the analysis, it was generally assumed that heavy construction equipment would be operating for approximately 8 hours per day, 5 days per week (22 days per month) during Proposed Project construction. CalEEMod defaults were applied for the worker, haul, and vendor trips (CAPCOA 2017). Notably, CalEEMod counts trips associated with road base materials, cement, and water trucks as vendor trips and are incorporated into the calculations of the Building Construction phase, as shown in Table 3.3-5.

Construction of Proposed Project components would be subject to BAAQMD’s Regulation 6.

This rule requires that Proposed Project construction include steps to restrict visible emissions of fugitive dust (BAAQMD 2018). Compliance with Regulation 6 would limit fugitive dust (PM10 and PM2.5) that may be generated during grading and construction activities.

A detailed depiction of the construction schedule—including information regarding subphases and equipment used during each subphase—is included in Appendix C.

Agenda Item #6.2.

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Operations
Emissions from the operational phase of the Proposed Project (if the Proposed Project is approved and when the Proposed Project is completed) were estimated using CalEEMod. Operational year 2029 was assumed as it would be the first full year following completion of construction.

Area Sources. CalEEMod was used to estimate operational emissions from area sources, including emissions from consumer product use, architectural coatings, and landscape maintenance equipment associated with the Proposed Project. Emissions associated with natural gas usage in space heating, hearths, water heating, and stoves were calculated in the building energy use module of CalEEMod, as described in the following text. Notably, it was assumed that hearth emissions would be from natural gas combustion.

Consumer products in this analysis are chemically formulated products used by household and institutional consumers, including detergents; cleaning compounds; polishes; floor finishes; cosmetics; personal care products; home, lawn, and garden products; disinfectants; sanitizers; aerosol paints; and automotive specialty products. Other paint products, furniture coatings, and architectural coatings are not considered consumer products in this case (CAPCOA 2017).

Consumer product ROG emissions were estimated in CalEEMod based on the floor area of residential buildings, and on the default factor of pounds of ROG per building square foot per day.

VOC off-gassing emissions result from evaporation of solvents contained in surface coatings such as in paints and primers used during building maintenance. CalEEMod calculates the VOC evaporative emissions from application of residential and nonresidential surface coatings based on the VOC emission factor, the building square footage, the assumed fraction of surface area, and the reapplication rate. Low VOC paint would be used in construction and regular maintenance activities.

Low VOC paint is generally considered to contain less than 50 grams of VOC per liter, which was assumed for both interior and exterior painting. The model default reapplication rate of 10% of area per year is assumed. Consistent with CalEEMod defaults, it is assumed that the residential surface area for painting equals 2.7 times the floor square footage, with 75% assumed for interior coating and 25% assumed for exterior surface coating (CAPCOA 2017).

Landscape maintenance includes fuel combustion emissions from equipment such as lawn mowers, rototillers, shredders/grinders, trimmers, chain saws, and hedge trimmers. The emissions associated with landscape equipment use are estimated based on CalEEMod default values for emission factors (grams per square foot of nonresidential building space per day) and number of summer days (when landscape maintenance would generally be performed) and winter days as a conservative measure. It is assumed that landscaping equipment would likely only operate during the week (not weekends); therefore, landscape operational days were assumed to be 180 days per year in CalEEMod (CAPCOA 2017).

Agenda Item #6.2.

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Energy Sources. As represented in CalEEMod, energy sources would include emissions associated with building electricity and natural gas usage (non-hearth). Electricity use would contribute indirectly to criteria air pollutant emissions; however, the emissions from electricity use are only quantified for GHGs in CalEEMod, since criteria pollutant emissions occur at the site of the power plant, which is typically off site. The 2019 Title 24 standards were approved and adopted by the California Building Standards Commission in December 2018. The 2019 standards became effective on January 1, 2020. CalEEMod default values were updated to reflect that the Proposed Project would comply with the requirements of the 2019 standards for this analysis.

Mobile Sources. Mobile sources for the Proposed Project would primarily be motor vehicles traveling to and from the Proposed Project. 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 proposed land use 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 ProposedProject-specific trip rates presented in the traffic study. The CalEEMod default and assumed trip rates are depicted in Table 3.3-6.

Table 3.3-6
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 Sources: CAPCOA 2017; Dudek 2020.

Note:
1 Weekday and Saturday trip rates were provided in the Proposed Project’s Traffic Impact Study. Sunday trips rates was adjusted based on the ratio of the CalEEMod default Sunday trip rates to the CalEEMod default Saturday trip rates.

Agenda Item #6.2.

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Thresholds of Significance
Consistent with Appendix G of the California Environmental Quality Act (CEQA) Guidelines, a significant impact would occur if development of the Proposed Project would do any of the following:
• Conflict with or obstruct implementation of the applicable air quality plan. • Result in a cumulatively considerable new increase of any criteria pollutant for which the project region is nonattainment under an applicable federal or state ambient air quality standard.
• Expose sensitive receptors to substantial pollutant concentrations. • Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people.

Notably, in the California Building Industry Association v. Bay Area Air Quality Management District case decided in 2015, the California Supreme Court held that CEQA does not generally require lead agencies to consider how existing environmental conditions might impact a project’s occupants, except where the project would significantly exacerbate an existing environmental condition. Accordingly, the significance criteria above related to exposure of sensitive receptors to substantial pollutant concentrations is relevant only to the extent that the project exacerbates existing air quality conditions.

The BAAQMD adopted updated CEQA Air Quality Guidelines, including new thresholds of significance, in June 2010 (BAAQMD 2010), and revised them in May 2011.4 The CEQA Air Quality Guidelines advise lead agencies on how to evaluate potential air quality impacts, including establishing quantitative and qualitative thresholds of significance. The BAAQMD CEQA Air Quality Guidelines were recently re-released in May 2017 and include the same thresholds as in the 2010 and 2011 Guidelines for criteria air pollutants, TACs, and GHGs (BAAQMD 2017a). These thresholds are based on substantial evidence identified in BAAQMD’s 2009 Justification Report (BAAQMD 2009) and are summarized in Table 3.3-7.

In general, the BAAQMD significance thresholds for criteria pollutants (ROG, NOx, PM10, PM2.5, and CO) address the first two air quality Appendix G CEQA significance criteria (listed above).

The BAAQMD maintains that these criteria pollutant thresholds are intended to maintain ambient air quality concentrations below state and federal standards and to prevent a 4 The BAAQMD resolutions adopting and revising the significance thresholds in 2011 were set aside by a judicial writ of mandate on March 5, 2012. In May 2012, the BAAQMD updated its CEQA Air Quality Guidelines to continue to provide direction on recommended analysis methodologies, but without recommended quantitative significance thresholds (BAAQMD 2012). On August 13, 2013, the First District Court of Appeal ordered the trial court to reverse the judgment and upheld the BAAQMD’s CEQA thresholds.

Agenda Item #6.2.

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cumulatively considerable contribution to regional nonattainment with ambient air quality standards. The TAC thresholds (cancer and noncancer risks) and local CO thresholds address the third Appendix G significance criterion, and the BAAQMD odors threshold addresses the fourth Appendix G significance criterion.

Table 3.3-7
Thresholds of Significance
Pollutant
Construction Thresholds Operational Thresholds
Average Daily Emissions
(lbs/day)
Average Daily Emissions
(lbs/day)
Maximum Annual Emissions
(tons/year)
ROG 54 54 10
NOx 54 54 10
PM10 82 (exhaust) 82 15
PM2.5 54 (exhaust) 54 10
PM10/PM2.5 (fugitive dust) Best Management Practices None Local CO None 9.0 ppm (8-hour average, 20.0 ppm (1-hour average) Risks and Hazards
(Individual Project)
Compliance with Qualified Community Risk Reduction Plan or
Increased cancer risk of >10.0 in a million
Increased noncancer risk of >1.0 Hazard Index (Chronic or Acute) Ambient PM2.5 increase >0.3 μg/m3 annual average
Zone of Influence: 1,000-foot radius from property line of source or receptor Risks and Hazards
(Cumulative)
Compliance with Qualified Community Risk Reduction Plan or
Cancer risk of >100 in a million (from all local sources) Noncancer risk of >10.0 Hazard Index (chronic, from all local sources) Ambient PM2.5 >0.8 μg/m3 annual average (from all local sources) Zone of Influence: 1,000-foot radius from property line of source or receptor Accidental Release of
Acutely Hazardous Air
Pollutants
None Storage or use of acutely hazardous material located near receptors or new receptors located near stored or used
acutely hazardous materials considered significant
Odors None Five confirmed complaints to BAAQMD per year averaged over 3 years
Source: BAAQMD 2017a.

Notes: lbs/day = pounds per day; tons/year = tons per year; ppm = parts per million; g/m3 = micrograms per cubic meter; ROG = reactive organic gases; NOx = oxides of nitrogen; PM10 = particulate matter with an aerodynamic resistance diameter of 10 micrometers or less; PM2.5 = fine particulate matter with an aerodynamic resistance diameter of 2.5 micrometers or less; CO = carbon monoxide The BAAQMD established their thresholds of significance for CEQA purposes based on the regional goal to attain the NAAQS and CAAQS. Since an AAQS is based on maximum pollutant levels in outdoor air that would not harm the public's health, and air district thresholds pertain to attainment of the AAQS, this means that the thresholds established by air districts are also protective of human health.

Agenda Item #6.2.

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Threshold Criteria not Applicable to the Proposed Project Due to the location and characteristics of the Proposed Project, certain significance criteria are not applicable to the Proposed Project and therefore, are not considered potential impacts.

These criteria are addressed briefly below but are not discussed further in this document.

Other Emissions/Odors
The BAAQMD has identified typical sources of odor in the CEQA Air Quality Guidelines, a few examples of which include manufacturing plants, rendering plants, coffee roasters, wastewater treatment plants, sanitary landfills, and solid waste transfer stations. While sources that generate objectionable odors must comply with air quality regulations, the public’s sensitivity to locally produced odors often exceed regulatory thresholds. Heavy-duty equipment on the Project site during construction would emit odors. However, the construction activity would be short-term and would cease to occur after individual construction is completed. Additionally, no other sources of objectionable odors have been identified for the Proposed Project. In regards to the exposure of objectionable odors to sensitive receptors, the Proposed Project is not a typical land use associated with the generation of a source of odor and would not generate odor impacts. Thus, Proposed-Project-related odor issues (the last significance threshold listed above) are not further evaluated.

Impacts and Mitigation Measures

3.3-1: Would the Proposed Project obstruct implementation of the applicable air quality plan? This impact would be less-than-significant.

An area is designated as “in attainment” when it is in compliance with the federal and/or state standards. These standards are set by the EPA or CARB for the maximum level of a given air pollutant that can exist in the outdoor air without unacceptable effects on human health or public welfare with a margin of safety. The Project site is located within the SFBAAB, which is designated non-attainment for the federal 8-hour O3 and 24-hour PM2.5 standards. The area is in attainment or unclassified for all other federal standards. The area is designated non-attainment for state standards for 1-hour and 8-hour O3, 24-hour PM10, annual PM10, and annual PM2.5.

On April 19, 2017, the BAAQMD adopted the Spare the Air: Cool The Climate - Final 2017 Clean Air Plan (BAAQMD 2017c). The BAAQMD CEQA Air Quality Guidelines identify a threestep methodology for determining a project’s consistency with the current Clean Air Plan. If the responses to these three questions can be concluded in the affirmative and those conclusions are supported by substantial evidence, then the BAAQMD considers that project to be consistent with air quality plans prepared for the Bay Area.

Agenda Item #6.2.

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The first question to be assessed in this methodology is “does the project support the goals of the Air Quality Plan”? The BAAQMD-recommended measure for determining project support for these goals is consistency with BAAQMD thresholds of significance. If a project would not result in significant and unavoidable air quality impacts, after the application of all feasible mitigation measures, the project would be consistent with the goals of the 2017 Clean Air Plan. As indicated in the following discussion with regard to Impact 3.3-2 below, the Proposed Project would result in less than significant construction and operational emissions and would not result in long-term adverse air quality impacts. Therefore, the Proposed Project would be considered to support the primary goals and be consistent with the BAAQMD current Clean Air Plan.

The second question to be assessed is “does the project include applicable control measures from the Clean Air Plan?” The 2017 Clean Air Plan contains 85 control measures aimed at reducing air pollution in the Bay Area. Projects that incorporate all feasible air quality plan control measures are considered consistent with the Clean Air Plan. The control strategies of the 2017 Clean Air Plan include measures in the categories of stationary sources, the transportation sector, the buildings sector, the energy sector, the agriculture sector, natural and working lands, the waste sector, the water sector, and super-GHG measures. Depending on the control measure, the tools for implementation include leveraging the BAAQMD rules and permitting authority, regional coordination and funding, working with local governments to facilitate best policies in building codes, outreach and education, and advocacy strategies.

Stationary Source Control Measures. The stationary source control measures are designed to reduce emissions from stationary sources including metal melting facilities, cement kilns, refineries, and glass furnaces, are incorporated into rules adopted by the BAAQMD and then enforced by the BAAQMD. Since the Proposed Project would not include any stationary sources of emissions. Therefore, the stationary source control measures of the Clean Air Plan are not applicable to the Proposed Project.

Transportation Control Measures. The transportation control measures aim to decrease emissions of criteria pollutants, TACs, and GHGs by reducing demand for motor vehicle travel, promoting efficient vehicles and transit service, decarbonizing transportation fuels, and electrifying motor vehicles and equipment. The Proposed Project would develop new residences located near existing residential uses. Furthermore, the Proposed Project would also develop pedestrian and bicycle facilities, eventually connecting the Regional Vine Trail from Calistoga to the Vallejo Ferry once these improvements are completed. Therefore, the Proposed Project would not conflict with the BAAQMD’s initiatives to reduce vehicle trips and vehicle miles traveled and would support alternative transportation.

Energy Control Measures. The energy control measures are designed to reduce emissions of criteria air pollutants, TACs, and GHGs by decreasing the amount of electricity consumed in the Agenda Item #6.2.

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Bay Area, as well as decreasing the carbon intensity of the electricity used by switching to less GHG‐intensive fuel sources for electricity generation. Notably, these measures apply to electrical utility providers and local government agencies, which would serve the Proposed Project. Therefore, the energy control measures of the Clean Air Plan are not applicable to the Proposed Project.

Building Control Measures. The BAAQMD has authority to regulate emissions from certain sources in buildings such as boilers and water heaters but has limited authority to regulate buildings themselves. Therefore, the strategies in the building control measures focus on working with local governments that do have authority over local building codes, to facilitate adoption of best GHG control practices and policies. The Proposed Project is required to meet Title 24 and CALGreen standards to reduce energy demand and increase energy efficiency.

Therefore, the Proposed Project would not conflict with the building control measures of the Clean Air Plan.

Agriculture Control Measures. Since the Proposed Project does not include any agricultural activities (the remaining one-acre vineyard is too small to be considered agriculture), the agriculture control measures of the Clean Air Plan are not applicable to the Proposed Project.

Natural and Working Lands Control Measures. Since the Proposed Project does not include the disturbance of any rangelands or large areas of wetlands, the natural and working lands control measures of the Clean Air Plan are not applicable to the Proposed Project.

Waste Management Control Measures. The waste management control measures focus on reducing or capturing methane emissions from landfills and composting facilities, diverting organic materials away from landfills, and increasing waste diversion rates through efforts to reduce, reuse, and recycle. The Proposed Project would comply with local requirements for waste management (e.g., recycling and/or composting services). Therefore, the Proposed Project would be consistent with the waste management control measures of the Clean Air Plan.

Water Control Measures. The Water Control Measures focus on reducing emissions of criteria pollutants, TACs, and GHGs by encouraging water conservation, limiting GHG emissions from publicly owned treatment works, and promoting the use of biogas recovery systems. These measures would apply to publicly owned treatment works and local government agencies and not the Proposed Project.

Super GHG Control Measures. The super‐GHG control measures are designed to facilitate the adoption of best GHG control practices and policies through the BAAQMD and local government agencies, which are not applicable to the Proposed Project.

Agenda Item #6.2.

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The Proposed Project would not conflict with any applicable control measures from the 2017 Clean Air Plan, as discussed above.

The third question to be assessed in this consistency methodology is “does the project disrupt or hinder implementation of any control measures from the Clean Air Plan?” Examples of how a project may cause the disruption or delay of control measures include a project that precludes an extension of a transit line or bike path or proposes excessive parking beyond parking requirements. The Proposed Project would not create any barriers or impediments to planned or future improvements to transit or bicycle facilities in the area, nor would it include excessive parking. Therefore, the Proposed Project would not hinder implementation of 2017 Clean Air Plan control measures.

In summary, the responses to all three of the questions with regard to Clean Air Plan consistency are affirmative and the Proposed Project would not conflict with or obstruct implementation of the Clean Air Plan. This is a less-than-significant impact.

Mitigation Measures
None required.

3.3-2: Would implementation of the Proposed Project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable federal or state ambient air quality standard? This impact would be less than significant.

Past, present, and future development projects may contribute to the SFBAAB adverse air quality impacts on a cumulative basis. Per BAAQMD’s CEQA Air Quality Guidelines, by its nature air pollution is largely a cumulative impact; no single project is sufficient in size to, by itself, result in nonattainment of ambient air quality standards. In developing thresholds of significance for air pollutants, BAAQMD considered the emission levels for which a project’s individual emissions would be cumulatively considerable. If a project exceeds the identified significance thresholds, its emissions would be considered cumulatively considerable, resulting in a significant adverse air quality impact to the region’s existing air quality conditions. Therefore, if the Proposed Project’s emissions are below the BAAQMD thresholds or screening criteria, then the Proposed Project would not result in a cumulatively considerable net increase of any criteria air pollutant.

The CalEEMod Version 2016.3.2 model was used to estimate emissions related to construction activities. CalEEMod input parameters, including the Proposed Project’s land use type and size, construction schedule, and anticipated construction equipment, were based on information provided by the Proposed Project applicant, or default model assumptions if Proposed Project specifics were unavailable.

Agenda Item #6.2.

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Construction
Sources of emissions during Proposed Project construction would include off-road construction equipment exhaust, on-road vehicles exhaust and entrained road dust (i.e., material delivery trucks and worker vehicles), paving, and architectural coating activities. Detailed assumptions associated with Proposed Project construction are included in Appendix C.

Average daily emissions were computed by dividing the total construction emissions by the number of active construction days, which were then compared to the BAAQMD construction thresholds of significance. Table 3.3-8 shows average daily construction emissions of O3 precursors (ROG and NOx), PM10 exhaust, and PM2.5 exhaust during Proposed Project construction under a 6-year buildout scenario.
5 Table 3.3-8
Average Daily Unmitigated Construction Emissions – 6-Year Buildout Years
ROG NOx PM10 Exhaust PM2.5 Exhaust
Pounds per Day
2023-2028 Construction 3.1 12.7 0.5 0.5
BAAQMD Construction
Thresholds
54 54 82 54
Exceed Threshold? No No No No
Source: See Appendix C for detailed results.

Notes: The values shown are average daily emissions based on total overall tons of construction emissions, converted to pounds, and divided by1,142 active work days.

ROG = reactive organic gases; NOx = oxides of nitrogen; PM10 = coarse particulate matter; PM2.5 = fine particulate matter As shown in Table 3.3-8 construction of future residences would not exceed BAAQMD significance thresholds under either buildout scenario. Criteria air pollutant emissions during construction would be less than significant. Although the BAAQMD does not have a quantitative significance threshold for fugitive dust, the BAAQMD’s CEQA Air Quality Guidelines recommend that projects determine the significance for fugitive dust through application of best management practices (BMPs). The Proposed Project contractor would be required as conditions of approval to implement the following BMPs that are required of all construction projects:

1. All exposed surfaces (e.g., parking/staging areas, soil piles, graded areas, and unpaved access roads) shall be watered two times per day.

2. All haul trucks transporting soil, sand, or other loose material off-site shall be covered. 5 Fuel combustion during construction and operations would also result in the generation of SO2 and CO.

These values are included in Appendix C. However, since the SFBAAB is in attainment of these pollutants, the BAAQMD has not established a quantitative mass-significance threshold for comparison and are not included in the project-generated emissions tables in this document. Notably, the BAAQMD does have screening criteria for operational localized CO, which are discussed in more detail below.

Agenda Item #6.2.

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3. All visible mud or dirt track-out onto local roads shall be removed using wet power vacuum street sweepers at least once per day. The use of dry power sweeping is prohibited.

4. All vehicle speeds on unpaved roads shall be limited to 15 miles per hour (mph).

5. All roadways, driveways, and sidewalks to be paved shall be completed as soon as possible. Building pads shall be laid as soon as possible after grading unless seeding or soil binders are used.

6. Idling times shall be minimized either by shutting equipment off when not in use or reducing the maximum idling time to 5 minutes (as required by the California Airborne Toxics Control Measure Title 13, Section 2485 of California Code of Regulations [CCR]).

Clear signage shall be provided for construction workers at all access points.

7. All construction equipment shall be maintained and properly tuned in accordance with manufacturer’s specifications. All equipment shall be checked by a certified mechanic and determined to be running in proper condition prior to operation.

8. Post a publicly visible sign with the telephone number and person to contact at the Lead Agency regarding dust complaints. This person shall respond and take corrective action within 48 hours. The BAAQMD’s phone number shall also be visible to ensure compliance with applicable regulations.

Implementation of the required fugitive dust control measures would ensure air quality and fugitive dust-related impacts associated with Proposed Project construction would remain less than significant.

Operations
Operation of the Proposed Project would generate criteria pollutant (including ROG, NOx, PM10, and PM2.5) emissions from mobile sources (vehicular traffic), area sources (consumer products, architectural coatings, and landscaping equipment), and energy sources (electrical consumption). CalEEMod was used to estimate daily emissions from Proposed-Project-related operational sources. Table 3.3-9 summarizes the operational emissions criteria pollutants that would be generated from the Proposed Project. Operational emissions were then compared to the BAAQMD operational thresholds.

Table 3.3-9
Daily Unmitigated Operational Emissions
Source
ROG NOx PM10 PM2.5
Pounds per Day
Area 3.6 1.8 0.2 0.2
Energy 0.1 0.5 <0.1 <0.1
Agenda Item #6.2.

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Table 3.3-9
Daily Unmitigated Operational Emissions
Source
ROG NOx PM10 PM2.5
Pounds per Day
Mobile 0.9 4.6 3.6 1.0
Total 4.6 6.9 3.8 1.2
BAAQMD Operational
Thresholds
54 54 82 54
Exceed Threshold? No No No No
Source: See Appendix C for detailed results.

Notes: The values shown are the maximum summer or winter daily emissions results from CalEEMod.

ROG = reactive organic gases; NOx = oxides of nitrogen; PM10 = coarse particulate matter; PM2.5 = fine particulate matter; <0.01 = value less than reported 0.1.

As indicated in Table 3.3-9, operational emissions of ROG, NOx, PM10, and PM2.5 would not exceed the BAAQMD significance thresholds resulting from development of the Proposed Project. Therefore, the Proposed Project would have a less-than-significant impact in relation to regional operational emissions.

Health Effects of Criteria Air Pollutants
Construction and operation of the Proposed Project would not result in emissions that exceed the BAAQMD emission thresholds for any criteria air pollutants, including ROG, NOx, PM10, or PM2.5. ROG emissions would be associated with motor vehicles, construction equipment, and architectural coatings; however, Proposed-Project-generated ROG emissions would not result in the exceedances of the BAAQMD thresholds, as shown in Table 3.3-8 and Table 3.3-9.

Generally, the VOCs in architectural coatings are of relatively low toxicity. Additionally, the Proposed Project would be required to adhere to Regulation 8, Rule 3 – Architectural Coatings, which restricts the VOC content of coatings.

ROG and NOx are precursors to O3, for which the SFBAAB is designated as nonattainment with respect to the NAAQS and CAAQS. The health effects associated with O3 are generally associated with reduced lung function. The contribution of ROG and NOx to regional ambient O3 concentrations is the result of complex photochemistry. The increases in O3 concentrations in the SFBAAB due to O3 precursor emissions tend to be found downwind from the source location to allow time for the photochemical reactions to occur. However, the potential for exacerbating excessive O3 concentrations would also depend on the time of year that the ROG emissions would occur because exceedances of the O3 AAQS tend to occur between April and October when solar radiation is highest. The holistic effect of a single project’s emissions of O3 precursors is speculative due to the lack of quantitative methods to assess this impact.

Nonetheless, because ROG and NOx emissions associated with Proposed Project construction and/or operation would not exceed the BAAQMD daily thresholds, it is not anticipated the Agenda Item #6.2.

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Proposed Project would contribute substantially to regional O3 concentrations and the associated health effects.

Construction and operation of the Proposed Project would not contribute to exceedances of the NAAQS and CAAQS for NO2. Health effects that result from NO2 and NOx include respiratory irritation, which could be experienced by nearby receptors during the periods of heaviest use of off-road construction equipment. However, Proposed Project construction would be relatively short-term, and off-road construction equipment would be operating at various portions of the site and would not be concentrated in one portion of the site at any one time. In addition, existing NO2 concentrations in the area are well below the NAAQS and CAAQS standards.

Construction and operation of the Proposed Project would not create substantial, localized NOx impacts. Therefore, the Proposed Project is not anticipated to result in potential health effects associated with NO2 and NOx.

CO tends to be a localized impact associated with congested intersections. As described in Impact 3.3-3 below, the Proposed Project would result in minimal new traffic trips that would not exceed the BAAQMD CO screening criteria resulting in the formation of potential CO hotspots.

Thus, the Proposed Project’s CO emissions would not contribute to significant health effects associated with this pollutant.

Construction and operation of the Proposed Project would also not exceed thresholds for PM10 or PM2.5 and would not contribute to exceedances of the NAAQS and CAAQS for particulate matter or obstruct the SFBAAB from coming into attainment for these pollutants. The Proposed Project would also not result in substantial DPM emissions during construction and operation, and therefore, would not result in significant health effects related to DPM exposure.

Additionally, the Proposed Project would implement dust control strategies and be required to comply with Regulation 6, Rule 6 – Prohibition of trackout and the BAAQMD fugitive dust BMPs, which limit the amount of fugitive dust generated during construction. Due to the minimal contribution of PM10 and PM2.5 during construction and operation, it is not anticipated that the Proposed Project would result in potential health effects associated related to particulate matter.

In summary, because construction and operation of the Proposed Project would not result in the exceedances of the BAAQMD significance thresholds for ROG, NOx, PM10, and PM2.5, and because the BAAQMD thresholds are based on levels that the SFBAAB can accommodate without affecting the attainment date for the AAQS and the AAQS are established to protect public health and welfare, it is anticipated that the Proposed Project would not result in health effects associated with criteria air pollutants.

Notably, there are numerous scientific and technological complexities associated with correlating criteria air pollutant emissions from an individual project to specific health effects or Agenda Item #6.2.

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potential additional nonattainment days, and methods available to quantitatively evaluate health effects may not be appropriate to apply to emissions associated with the Proposed Project, which cannot be estimated with a high-level of accuracy. Notwithstanding, because construction and operation of the Proposed Project would not result in exceedances of the BAAQMD significance thresholds for criteria pollutants, potential health impacts associated with criteria air pollutants would be less than significant.

Mitigation Measures
None required.

3.3-3: Would the Proposed Project expose sensitive receptors to substantial pollutant concentrations? This impact would be less than significant.

Criteria Air Pollutant Emissions and Associated Pollutant Concentrations As discussed above in Impact 3.3-2, because construction and operation of the Proposed Project would not result in the exceedances of the BAAQMD significance thresholds for ROG, NOx, PM10, and PM2.5, and because the BAAQMD thresholds are based on levels that the SFBAAB can accommodate without affecting the attainment date for the AAQS and the AAQS are established to protect public health and welfare, it is anticipated that the Proposed Project would not result in health effects associated with criteria air pollutants. Therefore, potential health impacts associated with criteria air pollutants would be less than significant.

Toxic Air Contaminants
The BAAQMD has adopted project and cumulative thresholds for three risk-related air quality indicators to sensitive receptors: cancer risks, noncancer health effects, and increases in ambient air concentrations of PM2.5. These impacts are addressed on a localized, rather than regional, basis in relation to sensitive receptors identified for a project. Sensitive receptors are groups of individuals, including children, older adults, the acutely ill, and the chronically ill, that may be more susceptible to health risks due to chemical exposure. Sensitive-receptor population groups are likely to be located at hospitals, medical clinics, schools, playgrounds, childcare centers, residences, and retirement homes. As previously discussed, the nearest sensitive receptors are single-family residences located approximately 20 feet east of the Project site.

The greatest potential for TAC emissions during construction would be DPM emissions from heavy equipment operations and heavy-duty trucks during construction of the Proposed Project, and the associated health impacts to sensitive receptors. As shown in Table 3.3-8, average daily particulate matter (PM10 or PM2.5) exhaust emissions generated by construction equipment Agenda Item #6.2.

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operation would be minimal, well below the BAAQMD significance thresholds. Moreover, for the purposes of modeling it is assumed construction would occur over an approximate 6-year period (1,142 active construction days), which equates to approximately 10% of the total 30-year analysis exposure period for residential receptors, after which Proposed-Project-related TAC emissions would cease. Furthermore, the Proposed Project would not require the extensive use of heavy-duty construction equipment, which is subject to CARB’s Airborne Toxic Control Measures for in-use diesel construction equipment to reduce DPM emissions, and it would not involve extensive use of diesel trucks.

Operation of the Proposed Project would not result in any non-permitted direct emissions (e.g., those from a point source such as diesel generators) or result in substantial diesel vehicle trips (i.e., delivery trucks). Therefore, the Proposed Project would not result in exposure of sensitive receptors in the vicinity of the Project site to substantial TAC concentrations due to either construction or operation and impacts would be less than significant.

Local Carbon Monoxide Concentrations
The BAAQMD thresholds of significance for local CO emissions is the 1-hour and 8-hour CAAQS of 20 ppm and 9ppm, respectively. By definition, this represent levels that are protective of public health. According to the BAAQMD, a proposed project would result in a less-thansignificant impact to localized CO concentrations if the following screening criteria are met (BAAQMD 2017a):

1. Project is consistent with an applicable congestion management program established by the county congestion management agency for designated roads or highways, regional transportation plan, and local congestion management agency plans.

2. The project traffic would not increase traffic volumes at affected intersections to more than 44,000 vehicles per hour.

3. The project traffic would not increase traffic volumes at affected intersections to more than 24,000 vehicles per hour where vertical and/or horizontal mixing is substantially limited (e.g., tunnel, parking garage, bridge underpass, natural or urban street canyon, below-grade roadway).

The Proposed Project would generate minimal new traffic trips, estimated to be approximately 900 weekday vehicle trips, and would comply with the BAAQMD screening criteria. Accordingly, Proposed-Project-related traffic would not exceed CO standards and therefore, no further analysis was conducted for CO impacts. Thus, the CO emissions impact would be less-thansignificant on a project-level and cumulative basis.

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Mitigation Measures
None required.

3.3.5 Cumulative Impacts
The cumulative context of an air pollutant is dependent on the specific pollutant being. O3 precursors are a regional pollutant; therefore, the cumulative context would be existing and future development within the entire SFBAAB. This means that O3 precursors generated in one location do not necessarily have O3 impacts in that area. Instead, precursors from across the region can combine in the upper atmosphere and be transported by winds to various portions of the air basin. Consequently, all O3 precursors generated throughout the air basin are part of the cumulative context.

The geographic scope for the cumulative analysis is Napa County and surrounding areas, which are located within the SFBAAB for O3. The SFBAAB includes all of Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, and Santa Clara counties, as well as the southern half of Sonoma County and the southwestern portion of Solano County. The BAAQMD establishes emissions thresholds for regional emissions.

Particulates (fugitive dust and DPM) and TACs would result in localized impacts in close proximity to pollutant sources. There are no other active cumulative projects in the immediate vicinity of the Project site that are anticipated to contribute to localized TAC exposure; therefore, an analysis of the cumulative effects is not addressed below.

3.3-4: Would the Proposed Project contribute to cumulative air quality emissions within the existing area? The Project’s contribution would not be considerable.

As previously discussed under Impact 3.3-2, the Proposed Project would not result in a cumulatively considerable increase in emissions of nonattainment pollutants. Therefore, the Proposed Project’s cumulative contribution would be negligible and impacts would not be considerable resulting in a less-than-significant cumulative impact.

Mitigation Measures
None required.

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3.3.6 References
BAAQMD (Bay Area Air Quality Management District). 2009. Revised Draft Options and Justification Report, California Environmental Quality Act Thresholds of Significance. October 2009.

Accessed March 2017. http://www.baaqmd.gov/~/media/files/planning-and-research /ceqa/revised-draft-ceqa-thresholds-justification-report-oct-2009.pdf?la=en.

BAAQMD. 2010. California Environmental Quality Act Air Quality Guidelines. May 2010.

Accessed March 2017. http://www.baaqmd.gov/~/media/files/planning-and-research /ceqa/draft_baaqmd_ceqa_guidelines_may_2010_final.pdf?la=en.

BAAQMD. 2012. California Environmental Quality Act Air Quality Guidelines. Updated May 2012.

Accessed March 2017. http://www.baaqmd.gov/~/media/Files/Planning%20and%20Research /CEQA/BAAQMD%20CEQA%20Guidelines_Final_May%202012.ashx?la=en.

BAAQMD. 2017a. 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.

BAAQMD. 2017b. Spare the Air: Cool the Climate - Final 2017 Clean Air Plan. April 19, 2017. http://www.baaqmd.gov/~/media/files/planning-and-research/plans/2017-clean-air-plan /attachment-a_-proposed-final-cap-vol-1-pdf.pdf?la=en.

BAAQMD. 2017c. “Air Quality Standards and Attainment Status.” Last updated January 5, 2017.

Accessed July 2018. http://www.baaqmd.gov/research-and-data/air-quality-standardsand-attainment-status.

BAAQMD. 2018. Regulation 6, Rule 1-General Requirements. http://www.baaqmd.gov/~/media /dotgov/files/rules/archive-2018-regulation-6-rule-1/documents/rg0601-pdf.pdf?la=en.

CAPCOA (California Air Pollution Control Officers Association). 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 (Air Resources Board). 2000. Risk Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled Engines and Vehicles. CARB, Stationary Source Division, Mobile Source Control Division. October 2000. Accessed October 26, 2016. https://www.arb.ca.gov/diesel /documents/rrpFinal.pdf.

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CARB. 2005. Air Quality and Land Use Handbook: A Community Health Perspective. April 2005.

Accessed August 2016. http://www.arb.ca.gov/ch/landuse.htm.

CARB. 2009. “ARB Fact Sheet: Air Pollution Sources, Effects and Control.” Page last reviewed December 2, 2009. Accessed October 2018. https://www.arb.ca.gov/research /health/fs/fs2/fs2.htm.

CARB. 2011. Regulation for In-Use Off-Road Diesel-Fueled Fleets. December 2011. Accessed December 2016. https://www.arb.ca.gov/msprog/ordiesel/documents /finalregorder-dec2011.pdf.

CARB. 2014. Regulation to Reduce Emissions of Diesel Particulate Matter, Oxides of Nitrogen and Other Criteria Pollutants from In-Use Heavy-Duty Diesel-Fueled Vehicles. January 2014.

Accessed December 2016. https://www.arb.ca.gov/regact/2014/truckbus14/tbfrooal.pdf.

CARB. 2016a. “Glossary of Air Pollution Terms.” Accessed October 26, 2016. http://www.arb.ca.gov /html/gloss.htm.

CARB. 2016b. “Overview: Diesel Exhaust and Health.” April 12, 2016. Accessed December 2016. https://www.arb.ca.gov/research/diesel/diesel-health.htm.

CARB. 2016c. “Ambient Air Quality Standards.” May 4, 2016. Accessed December 2016. http://www.arb.ca.gov/research/aaqs/aaqs2.pdf.

CARB. 2017. Inhalable Particulate Matter and Health (PM2.5 and PM10). https://www.arb.ca.gov /research/aaqs/common-pollutants/pm/pm.htm.

CARB. 2018. “Area Designation Maps/State and National.” Last reviewed December 28, 2018. http://www.arb.ca.gov/desig/adm/adm.htm.

CARB. 2019a. “Glossary.” Accessed January 2019. https://ww2.arb.ca.gov/about/glossary.

CARB. 2019b. “Ozone & Health.” https://ww2.arb.ca.gov/resources/ozone-and-health.

CARB. 2019c. “Nitrogen Dioxide & Health.” https://ww2.arb.ca.gov/resources /nitrogen-dioxide-and-health.

CARB. 2019d. “Carbon Monoxide & Health.” https://ww2.arb.ca.gov/resources /carbon-monoxide-and-health.

CARB. 2019e. “Sulfur Dioxide & Health.” https://ww2.arb.ca.gov/resources/sulfur-dioxide-and-health.

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CARB. 2019f. “iADAM: Air Quality Data Statistics.” Accessed September 2020. https://www.arb.ca.gov/adam/topfour/topfourdisplay.php.

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. SCH# 2010042001. October 23, 2018.

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

EPA (U.S. Environmental Protection Agency). 2013. “Integrated Science Assessment of Ozone and Related Photochemical Oxidants.” https://cfpub.epa.gov/ncea/isa /recordisplay.cfm?deid=247492.

EPA. 2016. “Criteria Air Pollutants.” July 21, 2016. Accessed June 2018. https://www.epa.gov /criteria-air-pollutants.

EPA. 2018a. “Criteria Air Pollutants.” March 8, 2018. Accessed October 2018. https://www.epa.gov /criteria-air-pollutants.

EPA. 2018b. “Region 9: Air Quality Analysis, Air Quality Maps.” Last updated September 28, 2018. http://www.epa.gov/region9/air/maps/.

EPA. 2019. “AirData: Access to Air Pollution Data.” Last updated June 13, 2018. Accessed November 2018. http://www.epa.gov/airdata/ad_rep_mon.html.

NRC (National Research Council). 2005. Interim Report of the Committee on Changes in New Source Review Programs for Stationary Sources of Air Pollutants. Washington, DC: The National Academies Press. https://doi.org/10.17226/11208.

WRCC (Western Regional Climate Center). 2016. Saint Helena, California (047643), Monthly Climate Summary. https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?ca7643.

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3.4 BIOLOGICAL RESOURCES

3.4.1 Introduction
This section describes the existing biological resources present within the proposed Hunter Subdivision Project (Proposed Project) site and vicinity, identifies associated regulatory requirements, evaluates potential impacts, and identifies feasible mitigation measures.

Comments received in response to the Notice of Preparation included general concerns regarding potential Proposed Project impacts to wildlife species and the Napa River, and specific concerns regarding potential Proposed Project effects on fish species in the Napa River. All of the concerns raised are addressed in this section. A copy of the Notice of Preparation and comments received is included in Appendix A.

Biological resources discussed herein were identified through the review and compilation of existing information and field reconnaissance surveys conducted by Dudek staff. Existing documentation of potential biological resources at the Project site include an Updated Biological Assessment report prepared by Wetland Research Associates (WRA), a Wetland Delineation prepared by Dudek, and the results of a rare plant survey all provided in Appendix D. Other sources reviewed are listed in Section 3.4.6, References.

3.4.2 Environmental Setting
This section provides information on the condition of natural resources in the region and on the Project site, the extent of sensitive natural communities and critical habitat, presence or absence of jurisdictional wetlands on the site, and the distribution and habitat requirements of special-status species that have been recorded from or are likely to occur in the Proposed Project vicinity and identifies the biological resources that could be affected by implementation of the Proposed Project.

Summary of Previous Studies
Wetland Delineation (North Fork Associates 2006): North Fork Associates conducted a formal wetland delineation of the Project site in July 2006. Two ditches were mapped as present in the Project site. No wetlands were identified during the fieldwork. The results of the delineation were summarized in a formal report (dated September 12, 2006). The U.S. Army Corps of Engineers (USACE) verified the delineation in 2008, which is valid for 5 years from the date of the letter.

Biological Assessment (WRA 2011): WRA conducted a field reconnaissance survey of the Project site in November 2011, to verify site conditions, assess habitat suitability for specialAgenda Item #6.2.

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status species, and evaluate the potential presence of any wetlands or other waters of the U.S.

The survey was conducted after any wetlands that may have formed as a result of the placement of fill assocated with the Napa River Flood Control project in 2010. No special-status species were detected in or near the Project site during the 2011 survey.

Updated Biological Assessment (WRA 2015): WRA conducted a biological assessment of the Project site in March 2015. The purpose of the survey was to compare existing site conditions to those documented in 2011. The report concluded that existing site conditions have not changed substantially since 2011. No special-status species were detected during the 2015 site assessment.

Summary of Studies Conducted as Part of This Project
The following technical studies and site assessments were conducted in 2018 and/or 2019 by Dudek and are included in Appendix D:
• In February 2018, Dudek conducted a biological reconnaissance survey to to verify WRA’s 2015 Biological Assessment. The survey included a general assessessment of on-site habitats and their potential to support various special-status plant and wildlife species and to characterize and map on-site vegetation communities. The survey consisted of pedestrian transects throughout the Project site to collect data related to biological resources present or potentially present within the site. An aerial photograph and digital georeferenced map with an overlay of the property boundary was used to map the vegetation communities and record any anecdotally observed special-status or sensitive biological resources while in the field. Incidental observations of wildlife (common and/or special-status) or wildlife sign (e.g., tracks, scat) were also recorded.

The field survey included the Project site only; however, general characteristics of adjacent properties were also noted during the survey by scanning with and without binoculars. A separate report summarizing Dudek’s February 2018 survey was not prepared because the results of the survey have been incorporated into this section. • In February and April 2019, Dudek biologists conducted a jurisdictional delineation to characterize and map wetland/aquatic areas potentially under the jurisdiction of USACE pursuant to Section 404 of the federal Clean Water Act and under California Department of Fish and Wildlife (CDFW) jurisdiction pursuant to Section 1600 of the California Fish and Game Code. Potentially jurisdictional features were delineated based on methodology described in the 1987 Corps of Engineers Wetlands Delineation Manual (USACE 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region (USACE 2008). Nonwetland waters of the United States are delineated based on the presence of an ordinary high water mark, as determined using the methodology in A Field Guide to Agenda Item #6.2.

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the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United States (USACE 2010).
• In June 2020, a Dudek botanist conducted a plant survey for the bent-flowered fiddleneck (Amsinckia lunaris), a California Rare Plant Rank (CRPR) 1B.2 species, which is defined by the California Native Plant Society (CNPS) as “fairly endangered in California.” The survey was conducted according to the 2018 CDFW plant survey protocol during the blooming period (March through June) when the plant would be evident and identifiable. No bent-flowered fiddleneck plants were detected.

Regional Setting
The City of St. Helena (City) is situated within the Napa Valley floor, bounded by the Mayacamas Mountain Range on the western and northern sides and the Howell Mountains on the eastern side. The City is generally characterized by a mix of urban development and agricultural uses with some undeveloped wooded hillsides to the east and west of downtown and wooded hillsides interspersed with residential development to the west of downtown (City of St. Helena 2018). The Project site is located approximately three blocks east of downtown and State Route 29, and west of the Napa River in an area of medium- to low-density housing.

The Proposed Project site is located in the North Coast Ranges geographic subregion, on the border of the Inner North Coast Ranges district and the Outer North Coast Ranges District (Jepson Flora Project 2019). The Inner North Coast Ranges district is characterized by low rainfall and hot, dry summers while the Outer North Coast Ranges district has more marine influences and is characterized by higher rainfall (Baldwin et al. 2012). The Napa Valley, in which the city is located, separates these two districts. The western hills of the Napa Valley contain more redwoods and mixed evergreen forest while the eastern hills are dominated by chaparral and oak woodlands. Rainfall is intermediate between the two districts and averages

34.61 inches a year and temperatures range from an average low of 36°F in January to an average high of 89°F in July (WRCC 2019).

Local Setting
The Project site has been extensively altered by past activities associated with agriculture, and the construction of the City’s Flood Protection Project, which included the placement of excess fill material from the Flood Protection Project on the site. The Project site is bordered on the south and east by medium-density residential development, to the northeast by the Napa River and associated riparian vegetation, and to the northwest by a gravel levee maintenance road/public trail and agricultural and rural residential land.

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Topography
The Project site is generally flat, with micro topography created by past agriculture and grading practices, including the placement of fill on the site. The current elevation of the site varies 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 above mean sea level to 230 feet above mean sea level.

See Section 3.6, Geology and Soils, for an in-depth discussion of soils, geology, and topography of the Project site.

Soils
The United States Department of Agriculture’s Natural Resources Conservation Service conducts soil surveys and creates maps representing the location and type of soil in order to aid in agricultural, conservation, and land use decisions. The Natural Resources Conservation Service identifies the following soils as occurring on the Project site (USDA 2019):
• Bale clay loam, 0 to 2% slopes
• Bale clay loam, 2 to 5% slopes
• Cole silt loam, 0 to 2% slopes
• Cortina very gravelly loam, 0 to 5% slopes, moist
Hydrology
The Project site is within the greater Napa River Watershed, which drains water from hillsides through the Napa Valley and into the San Pablo Bay, approximately 50 miles to the south (NCWICC 2019a). The Napa River flows from northwest to southeast approximately 500 feet north/northeast of the Project site. The Project site has been partially graded in the past for construction of a City storm water detention basin which is currently located directly north/northeast of the site. A drainage ditch along the southwestern edge of the Project site drains rainwater runoff from the site north and east and into this detention basin. See Section 3.9, Hydrology and Water Quality, for an in-depth discussion of drainage and hydrology on the Project site.

Vegetation Communities and Land Cover Types
One vegetation community, three anthropogenic land cover types, and two aquatic land cover types are present in the Project site. The vegetation community is California annual grassland.

Anthropogenic land cover types include agriculture (vineyard), ruderal, and upland swale.

Aquatic land cover types include seasonal wetlands and a drainage ditch. Table 3.4-1 provides a breakdown of the various vegetation communities or land cover types and Figures 3.4-1 and

3.4-2 graphically depicts this information. A more detailed discussion is included below.

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Date: 5/2/2019 - Last saved by: mwatson - Path: Z:\Projects\j1083901\MAPDOC\EIR\Bio\Figure3.4-1_VegetationCommunities.mxd Vegetation Communities and Land Cover Types
Hunter Subdivision Project
SOURCE: Bing Maps 2019
0 150 300Feet
Project Boundary
Upland Swale
Vegetation Communities and Landcover
AGS, Annual grassland
RUD, Ruderal
VIN, Vineyard
FIGURE 3.4-1
Upland Swale
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CAMPO CT

PASEO GRAND DR

SAN JUAN CT

DEL RIO CT
SW-3
SW-1
SW-4
D-1
D-2
SW-2
On-Site Seasonal Wetlands and Drainage Features
Hunter Subdivision Project
SOURCE: USDA 2016
0 80 160Feet
Project Boundary
Seasonal Wetland
Ditch
FIGURE 3.4-2
Detention
Basin
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Table 3.4-1
Vegetation Communities and Land Cover Types
Vegetation Community or Land Cover Type Acres
Vegetation Communities
California Annual Grassland 9.67
Subtotal 9.67
Anthropogenic Land Cover Types
Agriculture (Vineyard) 6.02
Ruderal 0.45
Upland Swale 0.02
Subtotal 6.49
Aquatic Land Cover
Seasonal Wetland 0.07
Ditch 0.06
Subtotal 0.13
Total 16.29
Source: Dudek 2019.

California Annual Grassland. California annual grassland comprises 9.67 acres of the Project site. Non-native and ruderal grass and forb species such as wild oat (Avena fatua), Mediterranean barley (Hordeum murinum), seaside barley (Hordeum marinum), redstem stork’s bill (Erodium cicutarium), wild radish (Raphanus sativus), and Italian thistle (Carduus pycnocephalus) are common in this vegetation community. This vegetation community does not correspond to any identified community in the Manual of California Vegetation, Online Edition, and it is not a sensitive natural community (CDFW 2018; CNPS 2018).

The California annual grassland on the Project site is mowed or disked on a semi-annual basis.

Although dominated by non-native grasses, the California annual grassland onsite provides foraging opportunities for raptor species. Additional wildlife that may use this vegetation community for foraging or breeding include ground-nesting birds such as mourning dove (Zenaida macroura), black-tailed jackrabbit (Lepus californicus), and fossorial mammals such as California vole (Microtus californicus) and Botta’s pocket gopher (Thomomys bottae).

Agriculture (Vineyard). An approximately 6.02-acre vineyard occupies the southwestern portion of the Project site along with an approximately 1-acre area of vineyard located in the southwestern “panhandle” portion of the site. These vineyards are maintained on an annual basis through pruning, mowing, and disking. Cultivated grapes (Vitis spp.) is the primary species in this land cover type, with a sparse herbaceous layer between vine rows consisting of nonnative grasses and forbs similar to those found in the adjacent California annual grasslands.

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Ruderal. Ruderal non-natural land cover type includes areas disturbed by anthropogenic or human activities that retain a pervious surface without vegetation or that support an assortment of weedy, non-native vegetation. Vegetation common in the 0.45 acres of ruderal land cover onsite include wild oat, prickly lettuce (Lactuca serriola), black mustard (Brassica nigra), and yellow star thistle (Centaurea solsitialis). On the Project site, ruderal areas include areas regularly maintained through disking and mowing. Vegetation in these areas is dominated by non-native annual species such as cheeseweed (Malva parviflora), winter marigold (Calendula arvensis), and grasses similar to those discussed in the annual grasslands.

Upland Swale. There is one upland swale in the northwest corner of the Project site. The swale directs surrounding surface runoff to the detention basin north of the Project site.

Apart from the detention basin, the upland swale is isolated from aquatic features.

Vegetation in the swale is consistent with the surrounding California annual grassland. No defined bed and bank are associated with the swale, which was likely excavated specifically for stormwater drainage purposes.

Seasonal Wetlands. Four seasonal wetlands occur in the California annual grassland onsite.

These areas are approximately 0.07 acres, combined, and are discernable from the surrounding grassland by a change in the dominant vegetation and/or lack of vegetation in the deepest portions due to seasonal ponding of water. Vegetation common in seasonal wetlands onsite include seaside barley, curly dock (Rumex crispus) and fiddle dock (Rumex pulcher), all of which are common in areas of seasonal inundation.

Drainage Ditch. An approximately 0.06-acre ditch runs the length of the northwestern edge of the Project site (see Figure 3.4-2, On-Site Seasonal Wetlands and Drainage Features).

Himalayan blackberry (Rubus armeniacus) brambles dominate the vegetation in the ditch. The farther northeast the ditch travels, the more incised it becomes. At the northeastern end of the Project site, the ditch is approximately five feet deep with a defined bed and bank, as well as a canopy of valley oak (Quercus lobata) trees. Himalayan blackberry, toyon (Heteromeles arbutifolia), poison oak (Toxicodendron diversilobum), and oak seedlings dominate the understory of the valley oak canopy.

Sensitive Natural Communities
Sensitive natural communities are communities that are of limited distribution statewide or within a county or region and are often vulnerable to environmental effects of projects. The CDFW maintains a list of natural vegetation communities. Those communities with a State or Global Rarity ranking of S or G 1 through 3 are considered sensitive (CDFW 2018). In addition to sensitive natural communities, wetlands and riparian vegetation communities otherwise protected under state and federal law are also considered sensitive.

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Based on review of available resources and observation of the previously disturbed nature of vegetation communities and land cover types within the Project site, no sensitive natural communities, as defined by the CDFW (2018), occur within the Project site (Figure 3.4-1).

Seasonal wetlands onsite, as well as the drainage ditch may be considered sensitive (Figure

3.4-2); these features are discussed in more detail under potentially jurisdictional wetlands and waters below.

Wildlife Movement and Nursery Sites
Wildlife corridors are linear features that connect large patches of natural open space and provide avenues for the migration of animals. Wildlife corridors contribute to population viability by assuring continual exchange of genes between populations, providing access to adjacent habitat areas for foraging and mating, and providing routes for recolonization of habitat after local extirpation (extinction) or ecological catastrophes (e.g., fires). Habitat linkages are small patches that join larger blocks of habitat and help reduce the adverse effects of habitat fragmentation. Habitat linkages provide a potential route for gene flow and long-term dispersal of plants and animals and may serve as primary habitat for smaller animals, such as reptiles and amphibians. Habitat linkages may be continuous habitat or discrete habitat islands that function as “steppingstones” for dispersal.

The Project site is bordered by development to the east, south, and agriculture to the north/northwest. The Napa River riparian corridor is located approximately 500 feet northeast of the Project site and is identified as a major, regional north-south wildlife movement route in Napa County (Napa County Watershed Information & Conservation Council 2018). Additional landscape blocks and habitat linkages are located to the north, east, and west of the Project site, but are at least 1.4 miles from the site (refer to Figure 3.4-3, Wildlife Corridors and Habitat Linkages).

While the mature trees and shrubs along the Napa River provide cover and essential habitat linkage for resident and migratory wildlife, the Project site itself does not function as a wildlife movement corridor due to the surrounding development, lack of connectivity with other undeveloped areas, and existing and historic agricultural uses of the site. The grassland on the Project site does not provide adequate cover or nursery sites for mammal species with the exception of small, fossorial mammals such as pocket gophers and field mice.

The Napa River, generally north of the site, supports native resident and migratory fish, including Chinook salmon and steelhead. The two linear features onsite are ephemeral and separated from the Napa River to the north by culverts that are not regularly open for drainage to the river (see details in Section 3.9, Hydrology and Water Quality). As such, these fish species are not expected to occur on or adjacent to the Project site.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-12
Special-Status Resources
For the purposes of this report, special-status plant species are those plants listed, proposed for listing, or candidates for listing as threatened or endangered by the U.S. Fish and Wildlife Service (USFWS) under the federal Endangered Species Act (FESA) (16 USC Section 1531 et seq.); those listed or proposed for listing as rare, threatened, or endangered by the CDFW under the California Endangered Species Act (CESA) (Fish & Game Code, Section 2050 et seq.); and plants that are CRPR 1 and 2 in the CNPS’s online Inventory of Rare and Endangered Plants (CNPS 2019). Special-status wildlife species are those that are designated as either rare, threatened, or endangered (or candidate) by CDFW or the USFWS; are protected under either the CESA or FESA; meet the California Environmental Quality Act (CEQA) definition for endangered, rare, or threatened (CCR Tit. 14, Section 15380(b),(d)); are considered fully protected under the California Fish & Game Code, Section 3511, 4700, 5050, and 5515; or that are on the CDFW Special Animals List (CDFW 2018) and determined by CDFW to be a Species of Special Concern.

As noted in the Methods of Analysis section below, WRA initially evaluated the potential occurrence of special-status plant and wildlife species on the Project site in 2015. Dudek biologists conducted additional resource database searches in 2018, 2019, and the species list was updated (Tables 3.4-2 and 3.4-3 and Figure 3.4-4, CNDDB Occurrences). This list was primarily derived from a review of the California Natural Diversity Database (CNDDB) (CDFW 2019), the CNPS Inventory of Rare and Endangered Plants (CNPS 2019), and the USFWS lists of federal endangered and threatened species (USFWS 2019).

The potential for those species identified in the literature search to occur on the Project site were evaluated based on the habitat requirements of each species relative to the observed existing conditions, results of previous general and focused habitat assessments and surveys for plants and animals conducted in November 3, 2011, and March 20, 2015 (WRA 2015), and surveys conducted by Dudek biologists on February 20, 2018, April 10, 2019, and June 1, 2020.

Special-Status Plants
Based on the review of the databases and other information sources, 57 special-status plant species are documented as occurring or potentially occurring in the vicinity of the Project site (Table 3.4-2). Review of Project site conditions and results of surveys conducted by WRA and Dudek staff biologists demonstrate that no special-status plants are expected to occur on the Project site for varying reasons such as the absence of habitat requirements for the species, the distance to known occurrences, the species distribution or elevation ranges, or species absence during focused protocol surveys.

Agenda Item #6.2.

Date: 5/2/2019 - Last saved by: mwatson - Path: Z:\Projects\j1083901\MAPDOC\EIR\Bio\Figure3.4-3_WildlifeCorridors_HabitatLinkages.mxd Wildlife Corridors and Habitat Linkages
Hunter Subdivision Project
SOURCE: CDFW 2015/2016, Bing Maps 2019
08 4,050 ,100
Feet
Project Boundary
5-Mile Radius from Project Boundary
Napa River Potential Riparian Connections
Essential Connectivity Areas
Lake Marie - The Cedars/ Adams Ridge
Linkage Design
Blue Ridge-Marin Coast
Coast Range-Blue Ridge
Natural Landscape Blocks
California Bay Area Linkage Network
California Essential Habitat Connectivity
FIGURE 3.4-3
Project Site
Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-14

INTENTIONALLY LEFT BLANK
Agenda Item #6.2.

Date: 5/2/2019 - Last saved by: mwatson - Path: Z:\Projects\j1083901\MAPDOC\EIR\Bio\Figure3.4-4_CNDDB.mxd CNDDB Occurrences
Hunter Subdivision Project
SOURCE: CDFW 2019, USFWS 2005/2012, Bing Maps 2019
0 3,000 6,000Feet
FIGURE 3.4-4
Project Boundary
CNDDB Species Occurence
Plant
1, Bent-flowered fiddleneck (Amsinckia lunaris)
2, Calistoga ceanothus (Ceanothus divergens)
3, Calistoga popcornflower (Plagiobothrys strictus)
4, Clara Hunt’s milk-vetch (Astragalus claranus)
5, Cobb Mountain lupine (Lupinus sericatus)
6, Colusa layia (Layia septentrionalis)
7, Green jewelflower (Streptanthus hesperidis)
8, Greene’s narrow-leaved daisy (Erigeron greenei)
9, Holly-leaved ceanothus (Ceanothus purpureus)
10, Jepson’s leptosiphon (Leptosiphon jepsonii)
11, Marsh checkerbloom (Sidalcea oregana ssp. hydrophila) 12, Napa bluecurls (Trichostema ruygtii)
13, Napa checkerbloom (Sidalcea hickmanii ssp. napensis) 14, Napa false indigo (Amorpha californica var. napensis) 15, Narrow-anthered brodiaea (Brodiaea leptandra)
16, Rincon Ridge ceanothus (Ceanothus confusus)
17, Sharsmith’s western flax (Hesperolinon sharsmithiae) 18, Sonoma ceanothus (Ceanothus sonomensis)
Wildlife
1, American peregrine falcon (Falco peregrinus anatum)
2, Bald eagle (Haliaeetus leucocephalus)
3, California giant salamander (Dicamptodon ensatus)
4, Foothill yellow-legged frog (Rana boylii)
5, Fringed myotis (Myotis thysanodes)
6, North American porcupine (Erethizon dorsatum)
7, Obscure bumble bee (Bombus caliginosus)
8, Pallid bat (Antrozous pallidus)
9, Purple martin (Progne subis)
10, Steelhead - central California coast DPS (Oncorhynchus mykiss irideus pop. 8)
11, Townsend’s big-eared bat (Corynorhinus townsendii)
12, Western pond turtle (Emys marmorata)
Critical Habitat
Northern Spotted Owl (Strix occidentalis caurina)
Steelhead (Oncorhynchus mykiss)

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-16

INTENTIONALLY LEFT BLANK

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-17
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Allium
peninsulare
var.
franciscanum
Franciscan
onion
None/None/1B.2 Cismontane woodland, Valley
and foothill grassland; clay,
volcanic, often
serpentinite/perennial
bulbiferous herb/(Apr)May–
June/170–1,000
Not expected to occur. No
clay, volcanic, or serpentinite
soils present.

Alopecurus
aequalis var.
sonomensis
Sonoma
alopecurus
FE/None/1B.1 Marshes and swamps
(freshwater), Riparian
scrub/perennial herb/May–
July/15–1,200
Not expected to occur. No
marsh or riparian scrub
habitat present.

Amorpha
californica var.
napensis
Napa false
indigo
None/None/1B.2 Broadleafed upland forest
(openings), Chaparral,
Cismontane woodland/
perennial deciduous
shrub/Apr–July/390–6,560
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Amsinckia
lunaris
bent-flowered
fiddleneck
None/None/1B.2 Coastal bluff scrub,
Cismontane woodland, Valley
and foothill grassland, often
serpentine/annual herb/Mar–
June/5–1,640
Not expected to occur. The
annual grassland onsite
provides marginal habitat for
this species due to a lack of
serpentine soils and past
and present anthropogenic
disturbances at the site.

Present mowing/vegetation
management and past
grading and agricultural uses
of the site likely preclude the
potential for this species to in
the Project site. The plant
survey did not identify the
presence of the plant (see
Appendix D).

Arctostaphylos
manzanita
ssp. elegans
Konocti
manzanita
None/None/1B.3 Chaparral, Cismontane
woodland, Lower montane
coniferous forest;
volcanic/perennial evergreen
shrub/(Jan)Mar–
May(July)/1,295–5,300
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no chaparral or
woodland habitat present.

Arctostaphylos
stanfordiana
ssp.
decumbens
Rincon Ridge
manzanita
None/None/1B.1 Chaparral (rhyolitic),
Cismontane woodland/
perennial evergreen
shrub/Feb–Apr(May)/ 245–
1,215
Not expected to occur. No
chaparral or woodland
habitat present.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-18
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Astragalus
claranus
Clara Hunt's
milk-vetch
FE/ST/1B.1 Chaparral (openings),
Cismontane woodland, Valley
and foothill grassland;
serpentinite or volcanic, rocky,
clay/annual herb/Mar–
May/245–900
Not expected to occur. No
serpentinite or volcanic,
rocky, clay soils present.

Astragalus
rattanii var.
jepsonianus
Jepson's milkvetchNone/None/1B.2 Chaparral, Cismontane woodland, Valley and foothill
grassland; often serpentinite/
annual herb/Mar–June/ 965–
2,295
Not expected to occur. The
site is outside of the species’
known elevation range.

Brodiaea
leptandra
narrowanthered
brodiaea
None/None/1B.2 Broadleafed upland forest,
Chaparral, Cismontane
woodland, Lower montane
coniferous forest, Valley and
foothill grassland;
volcanic/perennial bulbiferous
herb/May–July/360–3,000
Not expected to occur. The
site is outside of the species’
known elevation range.

Calycadenia
micrantha
small-flowered
calycadenia
None/None/1B.2 Chaparral, Meadows and
seeps (volcanic), Valley and
foothill grassland; Roadsides,
rocky, talus, scree, sometimes
serpentinite, sparsely
vegetated areas/annual
herb/June–Sep/15–4,920
Not expected to occur. No
chaparral, meadows and
seeps, or volcanic or
serpentine soils with sparse
vegetation present.

Castilleja
ambigua var.
meadii
Mead's owl'scloverNone/None/1B.1 Meadows and seeps, Vernal pools; Gravelly, volcanic,
clay/annual herb
(hemiparasitic)/Apr–
May/1,475–1,560
Not expected to occur. The
site is outside of the species’
known elevation range.

Ceanothus
confusus
Rincon Ridge
ceanothus
None/None/1B.1 Closed-cone coniferous
forest, Chaparral, Cismontane
woodland; volcanic or
serpentinite/ perennial
evergreen shrub/ Feb–
June/245–3,495
Not expected to occur. No
forest, chaparral, or
woodland habitat present.

Ceanothus
divergens
Calistoga
ceanothus
None/None/1B.2 Chaparral (serpentinite or
volcanic, rocky)/ perennial
evergreen shrub/Feb–
Apr/555–3,115
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-19
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Ceanothus
purpureus
holly-leaved
ceanothus
None/None/1B.2 Chaparral, Cismontane
woodland; volcanic,
rocky/perennial evergreen
shrub/Feb–June/390–2,100
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Ceanothus
sonomensis
Sonoma
ceanothus
None/None/1B.2 Chaparral (sandy, serpentinite
or volcanic)/perennial
evergreen shrub/ Feb–
Apr/705–2,625
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Centromadia
parryi ssp.
parryi
pappose
tarplant
None/None/1B.2 Chaparral, Coastal prairie,
Meadows and seeps,
Marshes and swamps
(coastal salt), Valley and
foothill grassland (vernally
mesic); often alkaline/annual
herb/May–Nov/0–1,380
Not expected to occur. No
alkaline soils present within
the vernally mesic areas of
the annual grassland onsite.

Cryptantha
dissita
serpentine
cryptantha
None/None/1B.2 Chaparral (serpentinite)/
annual herb/Apr–June/1,295–
1,905
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Downingia
pusilla
dwarf
downingia
None/None/2B.2 Valley and foothill grassland
(mesic), Vernal pools/annual
herb/Mar–May/0–1,460
Not expected to occur. No
vernal pool habitat present.

Erigeron
greenei
Greene's
narrow-leaved
daisy
None/None/1B.2 Chaparral (serpentinite or
volcanic)/perennial herb/May–
Sep/260–3,295
Not expected to occur. No
chaparral habitat present.

Eryngium
constancei
Loch Lomond
button-celery
FE/SE/1B.1 Vernal pools/annual/perennial
herb/Apr–une/1,505–2,805
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Eryngium
jepsonii
Jepson's
coyote thistle
None/None/1B.2 Valley and foothill grassland,
Vernal pools; clay/perennial
herb/Apr–Aug/5–985
Not expected to occur. No
potential vernal pool habitat
or clay soils present.

Fritillaria
liliacea
fragrant
fritillary
None/None/1B.2 Cismontane woodland,
Coastal prairie, Coastal scrub,
Valley and foothill grassland;
Often serpentinite/perennial
bulbiferous herb/Feb–Apr/5–
1,345
Not expected to occur. No
serpentine soils present in
the annual grassland onsite.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-20
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Fritillaria
pluriflora
adobe-lily None/None/1B.2 Chaparral, Cismontane
woodland, Valley and foothill
grassland; often
adobe/perennial bulbiferous
herb/Feb–Apr/195–2,315
Not expected to occur. No
adobe soils present within
the annual grassland onsite.

Harmonia
hallii
Hall's
harmonia
None/None/1B.2 Chaparral (serpentinite)/
annual herb/Apr–June/1,000–
3,200
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Hesperolinon
bicarpellatum
two-carpellate
western flax
None/None/1B.2 Chaparral (serpentinite)/
annual herb/ May–July/ 195–
3,295
Not expected to occur. No
chaparral habitat present.

Hesperolinon
sharsmithiae
Sharsmith’s
western flax
None/None/1B.2 Chaparral; serpentinite/annual
herb/May–July/885–985
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Juncus
luciensis
Santa Lucia
dwarf rush
None/None/1B.2 Chaparral, Great Basin scrub,
Lower montane coniferous
forest, Meadows and seeps,
Vernal pools/annual
herb/Apr–July/980–6,695
Not expected to occur. The
site is outside of the species’
known elevation range.

Lasthenia
burkei
Burke's
goldfields
FE/SE/1B.1 Meadows and seeps (mesic),
Vernal pools/annual
herb/Apr–June/45–1,970
Not expected to occur. No
vernal pool habitat present.

Lasthenia
conjugens
Contra Costa
goldfields
FE/None/1B.1 Cismontane woodland, Playas
(alkaline), Valley and foothill
grassland, Vernal pools;
mesic/annual herb/Mar–
June/0–1,540
Not expected to occur. No
vernal pool habitat or
alkaline mesic areas
present.

Layia
septentrionalis
Colusa layia None/None/1B.2 Chaparral, Cismontane
woodland, Valley and foothill
grassland; sandy,
serpentinite/annual herb/Apr–
May/325–3,595
Not expected to occur. The
site is outside of the species’
known elevation range.

Leptosiphon
jepsonii
Jepson's
leptosiphon
None/None/1B.2 Chaparral, Cismontane
woodland, Valley and foothill
grassland; usually volcanic
/annual herb/Mar–May/ 325–
1,640
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-21
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Limnanthes
vinculans
Sebastopol
meadowfoam
FE/SE/1B.1 Meadows and seeps, Valley
and foothill grassland, Vernal
pools; vernally mesic/annual
herb/Apr–May/45–1,000
Not expected to occur. No
vernal pool or vernally mesic
habitat present.

Lupinus
sericatus
Cobb
Mountain
lupine
None/None/1B.2 Broadleafed upland forest,
Chaparral, Cismontane
woodland, Lower montane
coniferous forest/perennial
herb/Mar–June/900–5,005
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Navarretia
leucocephala
ssp. bakeri
Baker's
navarretia
None/None/1B.1 Cismontane woodland, Lower
montane coniferous forest,
Meadows and seeps, Valley
and foothill grassland, Vernal
pools; Mesic/annual
herb/Apr–July/15–5,710
Not expected to occur. No
vernal pool or vernally mesic
habitat present.

Navarretia
leucocephala
ssp. pauciflora
few-flowered
navarretia
FE/ST/1B.1 Vernal pools (volcanic ash
flow)/annual herb/ May–
June/1,310–2,805
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Navarretia
leucocephala
ssp. plieantha
many-flowered
navarretia
FE/SE/1B.2 Vernal pools (volcanic ash
flow)/annual herb/ May–
June/95–3,115
Not expected to occur. No
potential vernal pool habitat
present.

Navarretia
myersii ssp.
deminuta
small
pincushion
navarretia
None/None/1B.1 Vernal pools (clay loam)/
annual herb/Apr–May/ 1,160–
1,165
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Navarretia
paradoxinota
Porter’s
navarretia
None/None/1B.3 Meadows and seeps;
Serpentinite, openings,
vernally mesic, often
drainages/ annual herb/May–
June(July)/ 540–2,755
Not expected to occur. The
site is outside of the species’
known elevation range.

Navarretia
rosulata
Marin County
navarretia
None/None/1B.2 Closed-cone coniferous
forest, Chaparral; serpentinite,
rocky/annual herb/ May–July/
655–2,085
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Penstemon
newberryi var.
sonomensis
Sonoma
beardtongue
None/None/1B.3 Chaparral (rocky)/ perennial
herb/Apr–Aug/2,295–4,495
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-22
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Plagiobothrys
strictus
Calistoga
popcornflower
FE/ST/1B.1 Meadows and seeps, Valley
and foothill grassland, Vernal
pools; alkaline areas near
thermal springs/annual
herb/Mar–June/295–525
Not expected to occur. No
alkaline areas near thermal
springs or vernal pool habitat
present.

Poa napensis Napa blue
grass
FE/SE/1B.1 Meadows and seeps, Valley
and foothill grassland;
alkaline, near thermal
springs/perennial herb/May–
Aug/325–655
Not expected to occur. The
site is outside of the species’
known elevation range.

Puccinellia
simplex
California
alkali grass
None/None/1B.2 Chenopod scrub, Meadows
and seeps, Valley and foothill
grassland, Vernal pools;
Alkaline, vernally mesic;
sinks, flats, and lake margins/
annual herb/Mar–May/5–
3,050
Not expected to occur. No
alkaline, vernally mesic, or
lake margin habitat present.

Sagittaria
sanfordii
Sanford's
arrowhead
None/None/1B.2 Marshes and swamps
(assorted shallow freshwater)/
perennial rhizomatous herb
(emergent)/May–Oct(Nov)/0–
2,135
Not expected to occur. No
potential habitat present.

Sidalcea
hickmanii ssp.
napensis
Napa
checkerbloom
None/None/1B.1 Chaparral; rhyolitic/perennial
herb/ Apr–June/1,360–2,000
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Sidalcea
oregana ssp.
hydrophila
marsh
checkerbloom
None/None/1B.2 Meadows and seeps, Riparian
forest; mesic/perennial
herb/(June)July–Aug/3,605–
7,545
Not expected to occur. The
site is outside of the species’
known elevation range.

Sidalcea
oregana ssp.
valida
Kenwood
Marsh
checkerbloom
FE/SE/1B.1 Marshes and swamps
(freshwater)/perennial
rhizomatous herb/June–
Sep/375–490
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Spergularia
macrotheca
var. longistyla
long-styled
sand-spurrey
None/None/1B.2 Meadows and seeps,
Marshes and swamps;
Alkaline/perennial herb/Feb–
May/0–835
Not expected to occur. No
meadows, seeps, marsh or
swamp habitat present.

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-23
Table 3.4-2
Special-Status Plant Species Occurrence Potential on the Project Site Scientific
Name
Common
Name
Status
(Federal/State/CRPR)1
Primary Habitat
Associations/ Life Form/
Blooming Period/ Elevation
Range (Feet)2 Potential to Occur
Streptanthus
batrachopus
Tamalpais
jewelflower
None/None/1B.3 Closed-cone coniferous
forest, Chaparral; serpentinite/
annual herb/Apr–July/1,000–
2,135
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Streptanthus
brachiatus
ssp.
brachiatus
Socrates Mine
jewelflower
None/None/1B.2 Closed-cone coniferous
forest, Chaparral; usually
serpentinite/perennial
herb/May–June/1,785–3,280
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Streptanthus
hesperidis
green
jewelflower
None/None/1B.2 Chaparral (openings),
Cismontane woodland;
serpentinite, rocky/annual
herb/May–July/425–2,495
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Streptanthus
morrisonii ssp.
elatus
Three Peaks
jewelflower
None/None/1B.2 Chaparral (serpentinite)/
perennial herb/June–
Sep/295–2,675
Not expected to occur. No
chaparral habitat present.

Streptanthus
vernalis
early
jewelflower
None/None/1B.2 Closed-cone coniferous
forest, Chaparral; serpentinite/
annual herb/Mar–May/2,000–
2,000
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Trichostema
ruygtii
Napa bluecurls None/None/1B.2 Chaparral, Cismontane
woodland, Lower montane
coniferous forest, Valley and
foothill grassland, Vernal
pools/annual herb/June–
Oct/95–2,230
Not expected to occur. No
vernal pool habitat present.

Trifolium
amoenum
two-fork clover FE/None/1B.1 Coastal bluff scrub, Valley and foothill grassland
(sometimes serpentinite)/
annual herb/Apr–June/15–
1,360
Not expected to occur. No
serpentine soils present in
the annual grassland onsite.

Trifolium
hydrophilum
saline clover None/None/1B.2 Marshes and swamps, Valley and foothill grassland (mesic,
alkaline), Vernal pools/annual
herb/Apr–June/0–985
Not expected to occur. No
mesic, alkaline habitat
present.

Viburnum
ellipticum
oval-leaved
viburnum
None/None/2B.3 Chaparral, Cismontane
woodland, Lower montane
coniferous forest/perennial
deciduous shrub/May–June/
705–4,595
Not expected to occur. The
site is outside of the species’
known elevation range and
there is no potential habitat
present.

Sources: Jepson Flora Project (2019) and CNPS (2019).

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-24
Status Legend:

FE: Federally listed as endangered
FT: Federally listed as threatened
SE: State listed as endangered
ST: State listed as threatened
CRPR 1A: Plants Presumed Extirpated in California and either Rare or Extinct Elsewhere CRPR 1B: Plants Rare, Threatened, or Endangered in California and Elsewhere CRPR 2A: Plants Presumed Extirpated in California, But More Common Elsewhere CRPR 2B: Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere .1 Seriously threatened in California (over 80% of occurrences threatened / high degree and immediacy of threat) .2 Moderately threatened in California (20-80% occurrences threatened / moderate degree and immediacy of threat) .3 Not very threatened in California (<20% of occurrences threatened / low degree and immediacy of threat or no current threats known) Bent-flowered fiddleneck (Amsinckia lunaris). Bent-flowered fiddleneck is a CRPR 1B.21 species found in coastal bluff scrub, cismontane woodland, and valley and foothill grasslands between 5 and 1,640 feet above mean sea level (CNPS 2019). This species often occurs on serpentine soils (Jepson Flora Project 2019). Bent-flowered fiddleneck blooms March through June (CNPS 2019). The nearest documented CNDDB occurrence for this species is located approximately 2 miles southeast of the Project site (Figure 3.4-1) (CDFW 2019b). This occurrence is based on a March 2010 collection of the species in ruderal grassland at the edge of a vineyard located approximately 2 miles to the southeast (CDFW 2019b). Due to a lack of serpentine soils, as well as the disturbed nature of the Project site, and past grading activities associated with development of the vineyard and the nearby detention basin, there is only marginally suitable habitat for this species on the site. Surveys conducted by Dudek biologists and botanists in April 2019 and again in June 2020, were conducted within the period when this plant would be evident and identifiable. Dudek botanists did not find evidence of this species on the Project site, nor were any species within the genus Amsinckia observed during the surveys, which involved one focused survey for the plant conducted according to CDFW plant survey protocol (CDFW 2018; refer to Appendix D). This species is not anticipated to occur within the Proposed Project development footprint.

A polygon representing previously documented occurrences for Geene’s narrow-leaved daisy (Erigeron greenei) and Clara Hunt’s milk-vetch (Astragalus claranus) encompass the Project site; however, this polygon is large and non-specific and represents historic occurrences. These occurrences are old and likely extirpated as a result of development within the city limits (CDFW 2019b). Additionally, past disturbance and the ubiquity of non-native grass cover at the site likely precludes the presence of these sensitive species. 1 CRPR 1B: Plants Rare, Threatened, or Endangered in California and Elsewhere; 2 Fairly endangered in California (20%–80% occurrences threatened/moderate degree and immediacy of threat).

Agenda Item #6.2.

3.4 – BIOLOGICAL RESOURCES
Hunter Subdivision Project EIR 10839
September 2021 3.4-25
Special-Status Wildlife
Based on results of the surveys conducted by WRA and Dudek staff biologists, review of the databases and other relevant sources, 24 special-status wildlife species have been documented as occurring or potentially occurring in the vicinity of the Project site. Of these species, two are considered to have potential for occurrence (Palid Bat and White-Tailed Kite); they are identified in Table 3.4-3 and discussed below. The remaining special-status animals are not expected to occur on the Project site for varying reasons such as the absence of essential habitat requirements for the species, the distance to known occurrences, and/or the species distribution and elevation ranges.

Table 3.4-3
Special-Status Wildlife Occurrence Potential on the Project Site Scientific Name Common Name
Status
(Federal/State)1 Habitat2 Potential to Occur
Fish
Oncorhynchus mykiss
irideus pop. 8
steelhead – central
California coast DPS
FT/None Coastal basins from
Redwood Creek south
to the Gualala River,
inclusive; does not
include summer-run
steelhead
Not expected to
occur. Although the
Project site is located
in the Napa River
watershed, the site is
not accessible to fish
residing in the Napa
River.

Oncorhynchus
tshawytscha
Chinook – Napa River
fall-run
None/None Genetically similar to
the Central Valley
fall/late fall-run
Evolutionary
Significant Unit (ESU).

Known to occur in the
Napa River watershed
(NCWICC 2019b).

Not expected to
occur. Although the
Project site is located
in the Napa River
watershed, the site is
not accessible to fish
residing in the Napa
River.

Amphibians
Dicamptodon ensatus California giant
salamander
None/SSC Known from wet
coastal forests and
chaparral near
streams and seeps
from Mendocino Co.
south to Monterey Co.
and east to Napa Co.

Aquatic larvae found
in cold, clear streams,
occasionally in lakes
and ponds. Adults
known from wet
forests under rocks
and logs near streams
and lakes.

Not expected to
occur. No stream or
seep habitat in the
present site. The
nearest documented
occurrence was
observed in 2016
along Sulphur Creek,
approximately 1.9
miles southwest of the
Project site (CDFW
2019b).

Agenda Item #6.2.