Preface Executive Summary 1 - Introduction 2 - Project Description 3 - Setting, Impacts, and Mitigation Measures 4 - Alternatives to the Project 5 - List of Persons Preparing this EIR 6 - Bibliography Appendices A - Notice of Preparation B - Responses to Notice of Preparation C - Goals, Objectives, Policies, Implementation Actions and Strategies D - General Plan Update Opinion Surveys CHAPTER 3.0 SETTING, IMPACTS AND MITIGATION MEASURES 3.1 GEOLOGY AND SOILS 3.1.1 Setting Geology The following information is taken from The City of Grass Valley General Plan Update Background Report, prepared by Quad Knopf. Nevada County is part of the Sierra Nevada Range, a geologic block approximately 400 miles long and 80 miles wide which extends in a north-south band along the eastern portion of California. The terrain of Nevada County is distinctly characterized by two features of the Sierra Nevada. The western third of the county is comprised of rolling foothills which form a transition between the low-lying Sacramento Valley and the mountains to the east. The area extending from the Yuba County line to just northeast of the Grass Valley/Nevada City area is generally comprised of metavolcanic (Mesazoic Jura-Trias Metavolcanic) and granitic (Mesazoic Granitic) formations. As seen in Figure 3.1-1, a geologic map of the Planning Area, the central Grass Valley area is located on quartz diorite, tonalite, trondhjemite, and quartz mozonite rocks. East and west of this area are Lake Combie complex rocks, and serpentinized ultramafic rocks at the northwest edge of the existing city limits. The Glenbrook area has gabbro and diabase, while Miocine-Pliocene volcanic rocks are found at the northwest area along Deadman Flat Road and at the east end of the Planning Area around the Nevada County Air Park. Grass Valley is not within an Alquist-Priolo zone as defined in DMG Special Report 42 (DMG 1997). However, ground movement can be felt in Grass Valley from earthquakes at intermediate distances (i.e., the Truckee earthquake of 1968) and from distant earthquakes (i.e., the Winters-Vacaville 1892 event) (Sydnor 1998). There are a number of mapped faults (Figure 3.1-2) within a fifty mile radius of the Planning Area. A fault is defined as "a planar or gently curving fracture in the earth's crust across which there has been relative displacement." When movement occurs along a fault, the energy generated is released as waves, which causes groundshaking. Groundshaking intensity varies with the magnitude of the earthquake, the distance from the epicenter, and the type of rock or sediment through which seismic waves move. The Planning Area is also located among the various alignments of the Foothills Fault Zone, described by the California Division of Mines and Geology as a Mesozoic (approximately 225 million years ago) fault system that has been reactivated in Cenozoic time (65 million years ago to present). It is believed that this system originated from tectonic forces exerted by the uplift of the Sierra Nevada Mountain Range. That makes this fault system different from most other fault zones in California, in that it is not generated by the tectonic pressures of plates moving past one another (i.e., the San Andreas fault system). This fault zone is generally considered inactive, although two short segments along the fault system have ruptured. Evidence of an earthquake has been found near Spenceville and is believed to have occurred sometime during the late Quaternary Period (approximately the last 1.6 million years). More recently (1975), an earthquake measuring 5.7 on the Richter Scale occurred near Oroville along a fault segment known as the Cleveland Hill fault, approximately 24 miles northwest of Grass Valley. The Cleveland Hill Fault is being studied under the Alquist-Priolo Special Studies Zone Act, which was designed to identify active fault zones and prohibit the construction of structures along these zones (City of Grass Valley 1996). By Alquist-Priolo definition, a fault is potentially active if it has shown evidence of surface displacement during Quaternary time (the last 1.6 million years). Therefore, due to the Spenceville and Oroville earthquakes, the Foothills Fault System is technically considered a potentially active system. However, recent studies along the Bear Mountain fault segment near Auburn indicate that the seismic hazard related to the system is very low. Due to these recent measurements, the lack of recent movement along the majority of the system, and the lack of tectonic plate movement in the fault system, it is unlikely (although not improbable) that a large magnitude earthquake would occur in this fault system. However, if an earthquake were to occur, it is most likely that the epicenter would be along the Cleveland Hill fault segment. In summary, the Grass Valley area is rated as a low-intensity earthquake zone. A low-intensity zone is defined by the United States Geological Survey (USGS) as an area that is likely to experience an earthquake measuring 5.0-5.9 in magnitude on the Richter scale, and a maximum intensity of VI or VII on the Modified Mercalli scale. The Richter scale measures the amplitude of seismic waves recorded by a seismograph, while the Modified Mercalli scale (Table 3.1-1) measures the intensity of an earthquake by the way it is felt and responded to by humans, and by the amount of damage it does to buildings and structures (City of Grass Valley 1996). TABLE 3.1-1 MODIFIED MERCALLI SCALE OF EARTHQUAKE INTENSITY Scale Effects I Earthquake shaking not felt. II Shaking felt by those at rest. III Felt by most people indoors; some can estimate duration of shaking. IV Felt by most people indoors. Having objects swing, windows and doors rattle, wooden walls and frames creak. V Felt by everyone indoors; many estimate duration of shaking. Standing autos rock. Crockery clashes, dishes rattle, and glasses clink. Doors close, open, or swing. VI Felt by everyone indoors and most people outdoors. Many now estimate not only the duration of the shaking, but also its direction and have no doubt as to its cause. Sleepers awaken. Liquids disturbed, some spilled. Small unstable objects displaced. Weak plaster and weak materials crack. VII Many are frightened and run outdoors. People walk unsteadily. Pictures thrown off walls, books off shelves. Dishes or glasses broken. Weak chimneys break at roofline. Plaster, loose bricks, unbraced parapets fall. Concrete irrigation ditches damaged. VIII Difficult to stand. Shaking noticed by auto drivers, waves on ponds. Small slides and cave-ins along sand or gravel banks. Stucco and some masonry walls fall. Chimneys, factory stacks, towers, elevated tanks twist or fall. IX General fright. People thrown to the ground. Steering of autos affected. Branches broken from trees. General damage to foundations and frame structures. Reservoirs seriously damaged. Underground pipes broken. X General panic. Conspicuous cracks in ground. Most masonry and frame structures destroyed along with their foundations. Some well-built wooden structures and bridges are destroyed. Serious damage to dams, dikes, and embankments. Railroads bent slightly. XI General panic. Large landslides. Water thrown out of banks of canals, rivers, lakes, etc. Sand and mud shifted horizontally on beaches and flatland. General destruction of buildings. Underground pipelines completely out of service. Railroads bent greatly. XII General panic. Damage nearly total, the ultimate catastrophe. Large rock masses displaced. Lines of sight and level distorted. Objects thrown into air. Source: California Division of Mines and Geology, 1973. Soils Grass Valley and the surrounding region are located in an area of mountainous upland soils (USDA 1993). Nine soil associations occur in Nevada County, and those that occur within the Grass Valley Planning Area are described below. Soil associations located north and northwest of Grass Valley may contain serpentine soils. Figure 3.1-3 illustrates the soil associations, and the text below provides a general description of the soils in the area. Central Grass Valley and land to the east, generally south of Wolf Creek, are located within the Josephine-Sites-Mariposa association, which exhibits undulating to very steep, well-drained loams formed over metasedimentary and metabasic rock. Vegetation in this area is mostly conifer-hardwood forest. Most of the soils in this association have depths of 40-60 inches to weathered bedrock. Josephine-Sites-Mariposa association soils have permeabilities in the range of 0.6 to 2.0 inches per hour (generally moderate permeabilities). Land to the northeast of central Grass Valley, generally north of Wolf Creek, is located in Secca-Boomer association soils, which have undulating to steep, well-drained and moderately well-drained gravelly silt loams and loams formed over metabasic rock. These soils have depths of 40-60 inches to weathered bedrock. Secca-Boomer association soils have permeabilities in the range of 0.2 to 0.6 inches per hour (moderately slow to slow permeabilities). Northwest of the city center, Aiken-Cohasset association soils exhibit gently sloping to steep, well-drained loams and cobbly loams formed over andesitic conglomerate and metabasic rock. Soil depths in this association are about 42-60 inches or more. Aiken-Cohasset association soils have permeabilities in the range of 0.2 to 0.6 inches per hour (moderately slow permeabilities). Finally, southeast of the central city, are Boomer-Sites-Sobrante association soils with undulating to steep, well-drained loams formed over metabasic rock. Most of these soils have depths of 40-60 inches or more to weathered bedrock. Boomer-Sites-Sobrante association soils have permeabilities in the range of 0.2 to 0.6 inches per hour, but Sobrante soils can have permeabilities up to about 2.0 inches per hour (moderately slow to moderate permeabilities). Slope Instability Unstable soils and geologic conditions have historically resulted from vegetation removal associated with wildfires, timber harvesting, mining, and grading as part of road building and site development. Depending on local topographic, geologic and hydrological conditions, significant precipitation can exacerbate unstable conditions, resulting in landslides and mudslides. Any area adjacent to a hydraulically mined area is subject to landslide activity due to the removal of supporting rock and soil. Under such conditions, earthquakes or heavy rains can initiate slide activity. Landslides are events in which surface masses of slope-forming earth move outward and downward from their underlying and stable floors in response to the force of gravity. Unstable or potentially unstable slopes are susceptible to slides, falls, creep, or mud flows. Although slope movement can occur in any type of rock material, certain bedrock formations exhibit a high susceptibility to such movement. This type of formation is generally not found in the western portion of the County (County of Nevada 1995), but could occur on a local basis. Figure 3.1-4 provides information identifying locations where soil type and steepness of slopes may cause landslide activity in the Planning Area. 3.1.2 Impacts Impact Evaluation Criteria: Based on consideration of Appendix G of the State CEQA Guidelines, the project would be considered in this EIR to have a significant adverse impact on geology, soils or seismicity if it would expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death involving: Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault. Strong seismic ground shaking. Seismic-related ground failure, including liquefaction. Inundation by seiche, tsunami, or mudflow. Landslides. The project would also be considered to have a significant impact if it would result in substantial soil erosion or the loss of topsoil, or the loss of a unique geologic feature. A significant adverse impact could also result if the project is located on: Strata or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse. Expansive soil creating substantial risks to life or property. Impact #3.1-1: Approval of projects in accordance with the updated General Plan in areas of unstable geology, including areas of natural soil or rock instability, fault rupture and areas made unstable by past activities of humans (e.g., mining) could result in ground failure, destruction of buildings, seismic shaking or hazards to occupants. This is a potentially significant impact. Discussion/Conclusion: The General Plan update includes the Safety Element, which addresses geologic hazards, including seismicity, slope instability and landslide activity. New development could result in exposure of additional people to geologic hazards. All safety and hazard risks are addressed by the single Safety Goal (1-SG), to reduce the potential risk of death, injury, property damage, and economic and social dislocation resulting from hazards. Specifically, the General Plan provides for assurance of a high level of protection from geologic and seismic hazards for all residents, structures, and vital services (1-SO). All new structures will be built in conformance with the Uniform Building Code, as directed by General Plan goals and objectives (1-SP and 11-SI). and utilize seismic shaking design criteria that will offer the highest protection from geologic activity. The City will review its building code enforcement practices and adjust to meet the goals and objectives of the General Plan, including those addressing instability and seismic considerations (6-LUI) and ensure the safety and structural integrity of housing and commercial/industrial facilities through code enforcement (2-SP). In addition, goals, policies, objectives and implementation actions and strategies have been incorporated in the General Plan for site-specific geologic studies in areas identified as potentially containing geologic hazards (11-SI). Therefore, this is a less-than-significant impact. Impact #3.1-2: Areas of landslide or mudflow could exist in the city and the Planning Area due to the combination of topography, slope, geology, soils and vegetative cover. In areas of sloping terrain, relatively permanent alteration to the natural topography may occur. If improper grading or cut-and-fill occurs, or if development is attempted on extremely steep slopes, it is likely that erosion, siltation, subsidence, or other unstable soil conditions could occur. Erosion will be most severe where soil cover is removed and soil particles are disturbed. This is a potentially significant impact. Discussion/Conclusion: Areas potentially affected by landslides are identified in Figure 3.1-4. Landslides and mudflows typically occur as a result of natural conditions combined with land disturbing activities, which set up preconditions for such incidents. Similarly, subsidence, erosion/siltation of waterways, and other unstable conditions may be caused by cut/fill and grading practices unsuitable to the site or area. The City's Grading Ordinance is the single most important instrument for assuring that land disturbance associated with new development minimize these impacts. Proper administration of this ordinance, including frequent field inspections during grading, is required to provide such assurances. The General Plan addresses City responsibilities for preventing landslides and mudflows with policies requiring adoption of uniform construction codes (1-SP), careful regulation of development on steep slopes (5-COSP), and prevention of excessive alteration of natural topography (6-SP). Further policy direction commits the City to cooperate with Nevada County in preparing a hillside/slope ordinance to regulate....density and intensity (42-LUP) and to encourage City standards throughout the Sphere of Influence (44-LUP). Complementing these policies is 7-CDI, directing the City to amend the zoning ordinance and other development codes to facilitate clustering. Therefore, the goals, policies, objectives and implementation actions and strategies contained in the General Plan Update serve as effective mitigation measures for addressing landslide exposure, and will result in a less-than-significant impact. Impact #3.1-3: Subsidence of the land could result in association with new or expanded development in areas of former mining activities. This is a potentially significant impact. Discussion/Conclusion: Subsidence in areas of former mining activities poses a potential subsidence hazard problem for new and expanded development in areas of former mining activities. Due to the potential extent of hazard areas and the relatively poor records and other information about site specific potential hazards, the General Plan directs the City to establish a comprehensive mine-related hazards program (6-SI). The program entails data, base mapping and special technical studies; technical coordination with state and local agencies; technical assistance to property owners; and site specific field investigations during project planning and review. The State Division of Mines and Geology has recently established a technical program to deal with old mine hazards, and will be a continuing source of advice and assistance to the City. The mine hazards program directed by 6-SI will reduce mine-related subsidence and related impacts to a less than significant level. Impact #3.1-4: Expansive soils could affect new or expanded development occurring in accordance with the General Plan Update. This is a potentially significant impact. Discussion/Conclusion: Implementation of the UBC, the City's Grading Ordinance and the goals, policies, objectives and implementation actions and strategies contained in the General Plan Update will serve as effective mitigation measures for dealing with potential expansive soil problems. Specifically, Safety Policy 1-SP addresses adopting current uniform codes for all new construction. Therefore, this is a less-than-significant impact. Impact #3.1-5: The project has the potential to impact unique geologic or physical features in the Planning Area. This is a potentially significant impact. Discussion/Conclusion: One unique geologic or physical feature, mine shafts and related features, have been identified and described in the General Plan. Mitigation measures have been included in the Safety Element to require site-specific geologic studies in areas where mine shafts may occur (6-SI). This will avoid potential hazards, and is therefore a less-than-significant impact. 3.1.3 Mitigation Measures The goals, objectives, and policies and implementation actions and strategies that address geology and soils stability include: 1-SG 1-SI 16-SI 1-SO 2-SI 42-LUP 2-SO 3-SI 1-COSG 1-SP 6-SI 4-COSG 2-SP 11-SI 5-COSP 4-SP 12-SI 7-COSI 7-SP 15-SI 8-COSI Implementation of these goals, objectives, policies and implementation actions and strategies will reduce the effects on geology and soils to a less than significant level, and no additional mitigation measures are required. 3.2 HYDROLOGY AND WATER QUALITY 3.2.1 Setting The information in the Setting Section is taken from the City of Grass Valley General Plan Update Background Report, prepared by Quad Knopf. Local Drainage The Planning Area lies primarily within the Wolf Creek drainage basin. Wolf Creek enters the Planning Area from the east in an east-west direction, and turns to the south as it passes through downtown Grass Valley, and continues south to its confluence with the Bear River. The South Fork of Wolf Creek and Little Wolf Creek drain the southeastern portion of the Planning Area and discharge into Wolf Creek in the central Grass Valley area. Alta Hill is located on the divide between the Wolf Creek and Deer Creek watersheds. Drainage north of this divide flows to Deer Creek. 100-Year Flood Areas As indicated by the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRM), the City of Grass Valley and the General Plan Planning Area are relatively well drained. Flooding during the 100-year flood event is limited to relatively narrow areas along Wolf Creek and its tributaries, as shown on Figure 3.2-1. Major transportation corridors do not appear to be susceptible to flooding in a 100-year flood event. To the extent culverts and storm drains are not maintained, other localized flooding could occur. Homes located in the flood hazard areas would be subject to flooding in a 100-year event unless mitigation is employed. Dam Failure Upstream on Deer Creek, the Nevada Irrigation District (NID) Scotts Flat Dam forms Scotts Flat Reservoir. Mapping prepared by NID illustrates the area projected to be inundated should the dam suddenly fail. From this map, it is apparent that none of the Grass Valley Planning Area would be inundated should such an event occur (NID 1993). Water Quality Wolf Creek is influenced by the discharge of treated effluent from the Grass Valley wastewater treatment plant and use of the creek by NID for transport of irrigation water. The NID use, which occurs from mid-April through mid-October, results in an approximately five-fold increase in stream flows in the affected area. Thus, dissolved oxygen remains in good supply for the maintenance for desirable aquatic biota (City of Grass Valley 1996). 3.2.2 Impacts Impact Evaluation Criteria: Appendix G of the CEQA Guidelines indicates that hydrology-related impacts can be considered significant if a project would: Violate Regional Water Quality Control Board water quality standards or waste discharge requirements. Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on- or off-site. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site. Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems to control. Place housing within a 100-year floodplain, as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map. Place within a 100-year floodplain structures which would impede or redirect flood flows. Require or result in the construction of new stormwater drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects. Impact #3.2-1: Future development in accordance with the General Plan Update could result in additional discharge into surface waters or other alteration of surface water quality in violation of Regional Water Quality Control Board standards or waste discharge requirements. This is a potentially significant impact. Discussion/Conclusion: Developments on watershed lands should be carefully evaluated for potential effects on surface water quality. Under the updated General Plan, new developments could be allowed that discharge additional runoff into surface waters. Processed wastewater discharges from the wastewater treatment facility will be subject to waste discharge requirements issued by the Regional Water Quality Control Board, which will require mitigation of significant water quality impacts. The construction of projects in the City of Grass Valley will be subject to City Grading Ordinance requirements, which will provide mitigation measures to address erosion and the introduction of construction materials into surface waters. Runoff from development may also discharges pollutants from motor vehicles, such as petroleum hydrocarbons, glycol, and dissolved heavy metals. Regulations under Section 402(p) of the federal Clean Water Act are now in effect. They involve control of pollution in stormwater discharges. In California, the Section 402(p) National Pollutant Discharge Elimination System (NPDES) stormwater permitting program is administered by the Regional Water Quality Control Boards on behalf of the U.S. Environmental Protection Agency (EPA). A 402(p) permit is required for most new developments that disturb over five acres. Mitigation measures have been identified in the goals, objectives, and policies implementation actions and strategies of the General Plan to ensure that potential impacts to surface waters are mitigated. This includes broad General Plan goals and accompanying objectives which call for the City to assure compliance with water quality regulations (6-COSG), protect ground and surface water quality (1-COSO) and include water quality in land use decisions (2-COSO). A specific policy instructs the City continue to implement water quality improvement plans, including stormwater separation and wastewater treatment plant expansion (21-COSP). Implementation of these standards will ensure a less-than-significant impact to surface water quality or Regional Water Quality Control Board standards and waste discharge requirements. Impact #3.2-2: Approval of projects in areas subject to inundation in the design-level (100-year) flood would result in potentially significant impacts. Discussion/Conclusion: Several areas within the Planning Area have been identified by the Federal Emergency Management Agency (FEMA) to be subject to flooding during a 100-year storm event. Development within these areas would subject persons and property to loss, injury and possibly death. Flood-prone areas may enlarge or contract as developments both up-stream and downstream occur. Upstream development may include a variety of alterations to existing conditions: more impervious surface, thus more runoff; altered drainage patterns, shifting the location of surface runoff; increases in runoff velocity; and alterations to water quality. Downstream developments may block flood waters, thus creating ponding and backup of previously freer flowing waters. Existing stormwater drainage systems will need to be expanded and new systems will need to be constructed as a result of development under the General Plan. The following new development areas in particular will require new or expanded services: Special Development Areas - Loma Rica Ranch, North Star, and Kenny Ranch Loma Rica Industrial Park and Nevada County Airpark area East Bennett area proposed for residential designation Bear River Mill site proposed for commercial designation Grass Valley presently administers a variety of regulations designed to prevent flooding and address stormwater management. These include a flood ordinance, various provisions of the zoning ordinance and subdivision ordinance, and construction codes for residential and non-residential developments. The City's Capital Improvement Program (CIP) contains a local stormwater drainage program and a regional stormwater drainage program, comprising a Drainage System Master Plan. CIP-planned projects extending through the Year 2015 includes numerous storm drainage improvements The General Plan addresses the multiple issues surrounding storm drainage, flood control, flood prevention, and flood avoidance in a variety of ways. The General Plan directs the City to carefully regulate development proposed for location in flood hazard areas (9-COSP) and to continue to regulate development to reduce the risks to life and property (7-SI). Acknowledging the changeable nature of flood prone areas, the General Plan calls for the revision of flood hazard maps at appropriate intervals to reflect the effects of land use changes (8-SI). Concerning new developments, specific implementation measures direct the City to avoid stream channel modifications (7-SI), require new developments to utilize on-site stormwater storage (8-SI), and establish site development standards to minimize impervious surface (9-SI), (13-CDP), (8-CDI). Encouraging a natural, as opposed to a structural approach to stormwater control, a General Plan policy directs the City to return to open space areas in which flooding poses a clear danger to life and property (11-COSP). Further, the Plan calls for amending the zoning ordinance and other development codes to facilitate clustering (7-CDI), thus providing additional development siting options on properties constrained by flooding and stormwater management considerations. In summary, the goals, objectives, policies, and implementation actions and strategies included in the General Plan will help to reduce potential impacts from drainage and flooding. In addition, the City of Grass Valley's CIP provides planning for improvements to drainage and flooding problems through the year 2015. However, without full provision of CIP flood and drainage related improvements through the life of the Plan (2020), this will remain a potentially significant impact. Impact #3.2-3: Future development associated with the General Plan Update could result in changes in the quality and quantity of ground waters, either through direct additions or withdrawals of groundwater. This is a potentially significant impact. Discussion/Conclusion: Groundwater quality and quantity may be affected by a number of factors. Primary factors are withdrawal rates contrasted with recharge rates, and quality degradation from surface sources. Unincorporated portions of the Planning Area contain both residential and non-residential developments which rely on ground water for their water supplies and/or septic system for sanitary waste disposal. The General Plan, reflecting long-standing City policy, encourages systematic annexation and extension of City services into unincorporated portions of the Planning Area (10-LUP). Large scale annexations are anticipated in the three SDAs, with smaller annexations of other areas on the periphery of the present City limits. As unincorporated areas are annexed into the City, public water and sewer services will replace reliance on well and on-site septic systems. This will have an overall effect of reducing reliance on ground water as a potable water source in the Planning Area and reduce the potential for groundwater contamination from improperly operating septic systems. Conversely, development occurring under the provisions of the General Plan will, inevitably cause naturally (water) absorptive areas to accommodate impervious surfaces, thus potentially affecting ground water recharge in some areas. This impact will be countered by the General Plan's protection of wetlands (25-LUP) and (2-COSG), as well as implementation of the Open Space Opportunity overlay and numerous policies and implementation actions/strategies which address natural areas and open space preservation and enhancement. Much remains to be learned about ground water locations, patterns, and trends in the Planning Area and throughout western Nevada County. Little is known, or predictable, about the consequences of surface actions, such as land development, on ground water in specific situations. However, the broad trends anticipated to occur under the General Plan, as described above, indicate that the Plan will have a less than significant impact on ground water quantity and quality. Impact #3.2-4: On-site disposal of wastewater in areas of poor soil permeability could result in groundwater or surface water contamination. This is a potentially significant impact. Discussion/Conclusion: Soils in the Planning Area have generally moderate to slow permeability. If projects with on-site wastewater disposal systems are approved, there is a potential for significant impacts to the environment through contamination of surface or groundwater with insufficiently treated wastewater. The Nevada County Department of Environmental Health regulates all on-site wastewater disposal systems, which must meet current health and safety standards. It is anticipated that the majority of new development will be on the municipal sewer system, and that septic systems will occur only on large residential parcels in areas not served by sewer. The General Plan and subsequent zoning ordinance amendment will assure that the minimum parcel size on which an on-site septic system may be permitted is 2 acres, an increase from the current General Plan's 1.5 acre minimum. Through annexation and service extension, parcels too small to accommodate effective on-site disposal systems and/or with currently failing systems will be provided service, thus alleviating the potential for ground and water contamination (9-LUI) and (10-LUI). The General Plan's commitment to protection of ground and water quality (15-COSO) directly addresses continued maintenance of small lot septic systems within the City limits. The General Plan will, therefore, reduce the effects of on-site disposal of wastewater to a less than significant level. 3.2.3 Mitigation Measures The General Plan Update includes goals, objectives, policies and implementation actions and strategies which will substantially mitigate significant impacts to hydrology and water quality. These goals, objectives, policies and implementation actions and strategies are as follows:

1-SG 2-LUO 2-SO 2-LUG 3-SO 3-LUO 16-COSO 5-SO 4-LUO 3-COSP 3-SP 7-LUO 4-COSP 5-SP 2-LUP 9-COSP 7-SP 12-LUP 11-COSP 1-SI 25-LUP 17-COSP 2-SI 1-COSG 18-COSP 3-SI 1-COSO 21-COSP 7-SI 2-COSO 1-COSI 8-SI 2-COSG 2-COSI 9-SI 7-COSO 3-COSI 10-SI 8-COSO 6-COSI 15-SI 5-COSG 8-COSI 16-SI 6-COSG 12-COSI 1-LUG 15-COSG 8-CDI

Implementation of these goals, objectives, policies and implementation actions and strategies along with the additional mitigation measure discussed below will ensure that any impacts to hydrology and water quality resulting from the 2020 General Plan Amendment will result in a less than significant impact Mitigation Measure #3.2-1: The Capital Improvement Program currently addresses services and improvements through 2015, as developed under the 1982 General Plan. The CIP shall be updated along with the Drainage System Master Plan in the future in order to extend service/infrastructure needs through 2020, reflecting the needs of the 2020 General Plan (Applies to Impacts #3.2-2 and #3.5-5). Effectiveness of Measure: Implementation of Mitigation Measure #3.2-1 will assure that a CIP is in place that will reflect City needs through the life of the General Plan. 3.3 BIOLOGICAL RESOURCES 3.3.1 Setting The following information is taken from The City of Grass Valley General Plan Update Background Report, prepared by Quad Knopf. Vegetation The Planning Area is located in a transition zone between the lower foothill elevations and the higher Sierra Nevada mountains. This transition zone is considered the Yellow Pine Belt (Storer and Usinger 1963) (Figure 3.3-1). Because it is a transition zone, a variety of intermingled species occur in the area that typically occur at zones of either higher or lower elevations. As well as being surrounded by ponderosa pines (Pinus ponderosa) and blue oaks (Quercus douglasii), the Grass Valley Planning Area also accommodates many other locally important natural communities. Localized areas of serpentine or gabbro support native plant species that have adapted to unique soil conditions other species cannot tolerate. Vernal pools, seasonally flooded depressions underlain with clay or hardpan soils, accumulate water and support unique native vegetation and wildlife species. Other areas of biological significance in the Grass Valley area include riparian corridors, creeks and tributaries that support native trees, shrubs, herbaceous vegetation and wildlife, including special status species listed by the United States Fish and Wildlife Service (USFWS), California Department of Fish and Game (CDFG), and/or California Native Plant Society (CNPS). As a transition area, the Yellow Pine Belt in the Grass Valley area is comprised of a number of specific habitat types. The following describes these habitat types using the system of Holland (1986). Northern Mixed Chaparral Located on rocky, south-facing slopes with sparse soil, this dense habitat type usually consists of little or no understory vegetation and is adapted to frequent fires. Dominant species include Nuttall's scrub oak (Quercus dumosa), chamise (Adenostoma fasciculatum), and various species of manzanita (Arctostaphylos) and California lilac (Ceanothus spp.). Additional characteristic species include: California buckeye (Aesculus californica), western redbud (Cercis occidentalis), mountain-mahogany (Cerococarpus betuloides), flannelbush (Fremontia californica), twinberry (Lonicera involucrata), canyon live oak (Quercus chrysolepis), interior live oak (Q. wislizenii), sugar bush (Rhus ovata), and poison oak (Toxicodendron diversilobum). Non-native Grassland Non-native grassland typically occurs on fine-textured, clay soils that alternate between excessively moist to drought-like conditions. Growth, flowering, seed setting and germination occur during the moist seasons. Characteristic grass species commonly include: wild oat (Avena spp.), brome (Bromus spp.), rye (Lolium spp.), and vulpia (Vulpia spp.), while associated annual wildflower species include filaree (Erodium spp.), California poppy (Eschscholtzia californica), Gilia (Gilia spp.), lupines (Lupinus spp.), and fiddleneck (Amsinckia spp.). Black Oak Woodland This community consists of moderately open to dense stands of California black oak (Quercus kelloggii) associated with Ponderosa pine (Pinus ponderosa). Although black oaks are fairly fire resistant, young stands (60 years) often cannot withstand a hot blaze. These trees are very intolerant to shade and will often decline in numbers where taller trees have created a denser canopy. Blue Oak Woodland Even though this community is dominated by blue oak (Quercus douglassii), it may also include other oak species along with foothill pine (Pinus sabiniana). While the associated foothill pines do not tolerate frequent fires, blue oaks have adapted to them by becoming vigorous stump-sprouters. Although most commonly observed as an intermingled woodland, pure stands of blue oaks occur in a thin zone between foothill pine woodlands (lower elevations) and black oak woodland (higher elevations). Other common associated plants include manzanita (Arctostaphylos spp.), lilac (Ceanothus spp.), yerba santa, (Eriodictyon californicum), spiny redberry (Rhamnus crocea), California coffeeberry (R. californica), and Hansen's larkspur (Delphinium hansenii). Canyon Live Oak Forest This dense, evergreen vegetation community is dominated by canyon live oak (Quercus chrysolepis) and typically forms forests with little understory in canyons on north-facing slopes, while on south-facing slopes it forms low-growing, chaparral-like stands. Soils are typically rocky and have little soil development. Trees often have multiple trunks, a condition probably resulting from crown-sprouting after fire. Associated species include incense cedar (Calocedrus decurrens), Douglas fir (Pseudotsuga menziesii), and California bay (Umbellaria californica). Foothill Pine-Oak Woodland This community contains a mixture of foothill pines (Pinus sabiniana) and blue oak (Quercus douglasii), and is much more common than pure stands of either species. It is found on well-drained soils along rocky ridges or in canyons. Understories usually consist of annual herbaceous plants, and other associated species include various oak species such as canyon live oak (Q. chrysolepis), Nuttall's scrub oak (Q. dumosa), California black oak (Q. kelloggii), valley oak (Q. lobata), and interior live oak (Q. wislizenii). Westside Ponderosa Pine Forest The primary plant community in the Grass Valley area is open forest dominated by ponderosa pine (Pinus ponderosa), with sparse scattered chaparral shrubs and young trees. It usually occurs on coarse soils and will intermingle with a number of other vegetation communities. This community, which contains a mixture of foothill pines (Pinus sabiniana) and blue oak (Quercus douglassii), is much more common than pure stands of either species and is found on well-drained soils along rocky ridges or in canyons. Understory usually consists of annual herbaceous plants and other associated species, including various oak species such as canyon live oak (Q. chrysolepis), Nuttall's scrub oak (Q. dumosa), California black oak (Q. kelloggii), valley oak (Q. lobata), and interior live oak (Q. wislizenii). Other species that may occur in this community include white fir (Abies concolor), greenleaf manzanita (Arctostaphylos patula), coffeeberry (Rhamnus californica), incense cedar (Calocedrus decurrens), mountain misery (Chamaebatia foliolosa), sugar pine (Pinus lambertiana), canyon live oak (Quercus chrysolepis), and California black oak (Q. kelloggii). Riparian Habitats Riparian and aquatic communities are represented by several creeks in the Grass Valley area, namely, the lower portion of Wolf Creek, Squirrel Creek and South Fork Wolf Creek. Dominant vegetation found along these waterways includes dogwood (Cornus ssp.), box elder (Acer negundo), alder (Alnus ssp.), Fremont cottonwood (Populus fremontii ssp. fremontii) and big leaf maple (Acer macrophyllum). In the Planning Area, these communities contain declining native populations of riparian valley oaks (Quercus lobata), northwestern pond turtles (Clemmys marmorata marmorata), foothill yellow-legged frogs (Rana boylii), and western spade foot toads (Scaphiopus hammondii). Portions of these streams are becoming increasingly urbanized, therefore jeopardizing the health of these native populations. Wildlife Due to the variety of vegetation communities, many different wildlife species exist or have a high potential to exist in the Planning Area. Resident deer, as well as migratory deer from the Downieville and Nevada City deer herds, are known to inhabit the area. The Downieville/Nevada City Deer Herd Management Plan (CDFG/USFWS 1985) and California Department of Fish and Game (Grass Valley Regional Wildlife Manager Jeff Finn) were consulted for current herd statistics and critical habitat designations. Of particular concern is the portion of the herd's range known as Critical Winter Range. These are areas determined by state and federal agencies to be critical to the life cycle of migratory deer. Also of interest is a potential fisheries resource along Wolf Creek. Revegetation along the stream and restocking could bring back native fish. Following is a brief description of wildlife species that may potentially occur within the Planning Area. Migratory and Upland Bird Species Because California is located within the Pacific Flyway (the migration route through the western portion of the United States), various species of waterfowl routinely migrate through the area. The Grass Valley area is a prime location for migrating bird species due to existing riparian, grassland and tree covered areas. Common migratory waterfowl that may utilize the Grass Valley area include: Canada geese (Branta canadensis), mallard (Anas platyrhynchos), cinnamon teal (Anas cyanoptera), American wigeon (Anas americana), common goldeneye (Bucephala clangula), bufflehead (Bucephala albeola), and common merganser (Mergus merganser). Observed raptor species include red-tailed hawk (Buteo jamaicensis), sharp-shinned hawk (Accipiter striatus) and American kestrel (Falco sparverius). There are also many passerine and nonpasserine birds that migrate from colder climates to the warmer weather of the southern United States and elsewhere. Upland bird species such as California quail (Callipepla californica) are also commonly observed in the Grass Valley vicinity. Other Common Species The Grass Valley area is also host to many other wildlife species. Documented rodent species include deer mouse (Peromyscus maniculatis), western harvest mouse (Reithrodontomys megalotis), California meadow vole (Microtis californicus), Botta's pocket gopher (Thomomys bottae) and beaver (Castor canadensis). These populations provide a constant food source for predatory species such as the coyote (Canis latrans), bobcat (Lynx rufus), and gray fox (Urocyon cinereoargenteus), as well as for several raptors. In addition, the Grass Valley area also supports limited potential winter habitat for the bald eagle (Haliaeetus leucocephalus) in the form of riparian corridors. Sensitive Species The Federal Endangered Species Act (1973) and the California Endangered Species Act (1984) provide legal protection for plant and animal species in danger of becoming extinct. The Federal Endangered Species Act requires the United States Fish and Wildlife Service (USFWS) to provide a findings report on any federally accredited actions that could jeopardize the existence of any federally listed species. The California Department of Fish and Game (CDFG) analyzes projects for possible impacts to species as well as their habitats. The California Native Plant Society (CNPS) helps to determine which plant species and habitats should be listed as special status under the California Endangered Species Act. Consultation with the CDFG Natural Diversity Data Base (NDDB, 1997) revealed six sensitive species potentially located within the Grass Valley and Chicago Park USGS 7.5 minute quadrangles. These species are listed in Table 3.3-1. The following is a description of each: Stebbin's Morning Glory (Calystegia stebbins II) Stebbin's morning glory occurs on red clay soils of gabbro or perhaps serpentine origins in chaparral. A query of the California Department of Fish and Game Natural Diversity Database (NDDB 1997) revealed that this species may occur near the Planning Area in open grassland near the junction of South Ponderosa Way and Squirrel Creek Road. This plant is listed as endangered by both the USFWS and the CDFG. Pine Hill Flannelbush (Fremontodendron californicum ssp. decumbens) Pine Hill flannelbush is a gabbro or serpentine endemic, growing on rocky ridges with these substrates in chaparral or cismontane woodlands at elevations of about 1,400 to 2,000 feet. In Nevada County it is known to be near the old Nevada County Landfill on McCourtney Road. It is partially protected at this site via the establishment of fenced designated endangered plant protection areas. This plant is listed as endangered by the USFWS and as Rare in California. Red-anthered Rush (Juncus marginatus var. marginatus) Red-anthered rush is found in marshes and swampy places in the foothills of the Sierra Nevada at elevations below about 3,300 feet. It is a CNPS List 2 Species (Plants categorized as Rare, Threatened, or Endangered in California but more common elsewhere). Follett's Monardella (Monardella folletti) Follett's monardella grows on open, rocky, serpentine slopes in lower montane coniferous forests at elevations ranging from about 1,800 to 6,500 feet. It is known from Plumas and Nevada Counties, and is on the CNPS List as a 1B species (Plants categorized as Rare, Threatened, or Endangered in California and elsewhere). Scadden Flat Checkerbloom (Sidalcea stipularis) Sidalcea stipularis is known only from the Scadden Flat area along Highway 20, just west of Grass Valley. It grows in marshy areas at an elevation of about 2,400 feet. It is listed as a Federal Species of Concern and an Endangered species in California. California Horned Lizard (Phrynosoma coronatum frontale) The horned lizard occurs in valley-foothill hardwood, conifer and riparian habitats as well as in pine-cypress, juniper and annual grass habitats. It ranges from southern Tehama County to the southern California Desert Regions, preferring open country, especially sandy areas, washes and flood plains. It is listed as a Federal Species of Concern. Blacktail Deer According to California Department of Fish and Game (CDFG) Regional Wildlife Manager, Jeff Finn, deer are not a significant issue to the City of Grass Valley. However, the Downieville/Nevada City Deer Herd does migrate from higher elevations in the Sierra Nevada to just north of the City of Grass Valley. The Planning Area does not contain any designated Critical Winter Range for the Downieville/Nevada City Deer Herd (CDFG 1985). Table 3.3-1 lists sensitive species that may occur in the Planning Area. Wetlands Wetland communities support aquatic and other hydrophytic vegetation. Wetland sites are typically flooded marshy areas that vary in size and proportion to the particular topography and hydrology of the area. These sites are either seasonally or permanently wet and are dominated by perennial, emergent monocots such as cattail (Typha spp.), sedge (Carex spp.), rush (Juncus spp.), spikerush (Eleocharis spp.) and tule (Scirpus spp.). According to the USGS Wetlands Inventory Map for the Grass Valley and Chicago Park USGS 7.5 minute quadrangles, there are several identified wetlands within the Planning Area (Figure 3.3-2). Activities within "jurisdictional" wetlands requires a U.S. Army Corps of Engineers Section 404 Clean Water Act permit, California Regional Water Quality Control Board Clean Water Certification or Waiver, and California Department of Fish and Game Streambed Alteration Agreement. TABLE 3.3-1 SENSITIVE SPECIES POTENTIALLY OCCURRING IN THE GRASS VALLEY PLANNING AREA

Scientific Name Common Name Status Fed State CNPS Animals Phrynosoma coronatum frontale California horned lizard FSC CE N/A Plants Calystegia stebbinsii Stebbin's morning-glory FE CE 1B Fremontodendron decumbens Pine Hill flannelbush FE CR 1B Juncus marginatus var. marginatus Red anthered rush Monardella follettii Follett's monardella --- --- 1B Sidalcea stipularis Scadden Flat checkerbloom FSC CE 1B FE Federal Endangered Species FSC Federal Species of Concern CE California State Endangered Species CR Species listed as Rare in California CNPS1B Plants categorized by the California Native Plant Society as Rare, Threatened or Endangered in California and Elsewhere CNPS 2 Plants categorized by the California Native Plant Society as Rare, Threatened or Endangered in California but more common Elsewhere N/A Not Applicable --- None Sources: California Department of Fish and Game, 1997. California Natural Diversity Data Base, California Department of Fish and Game, Sacramento, CA. Skinner, M.W., and B.M. Pavlik (eds.). 1994. Inventory of rare and endangered vascular plants of California. Special Publication No. 1 (fifth edition), California Native Plant Society, Sacramento, CA.

Important Biological Resource Areas The 1982 General Plan Update for the City of Grass Valley listed four sensitive habitats. Following are brief descriptions of these areas, as found in the 1981-82 General Plan. Important Natural Community Areas of Nevada County, California (1998) provided additional information regarding these areas and three additional sites. Important biological resource areas in the Grass Valley Planning Area are discussed below and illustrated on Figure 3.3-3. Scadden Flat Marsh Four acres west of Grass Valley along Highway 20 and north of the Nevada County Fairgrounds contain a freshwater marsh that supports a wet and dry meadow surrounded by a ponderosa pine forest. Scadden Flat hosts the only documented population of Scadden Flat Checkerbloom (Sidalcea stipularis). This area is threatened by grazing, encroachment of non-native plant species, poor water quality and destruction due to vehicles. Hell's Half Acre Hell's Half Acre is a local example of northern volcanic mudflow vernal pool habitat about 1.5 miles northwest of Grass Valley. This habitat consists of open, rocky flats surrounded by Foothill and Ponderosa Pines. The 70-acre area contains over 100 species of indigenous or rare plants (Lonsdorf 1998), including the best example of a low elevation wildflower field in the north-central Sierra Nevada. It supports many native plant species such as Sanborn's onion (Allium sanbornii var. sanbornii), Lemon's stipa (Achnatherum lemmonii var. pubescens), Kettledome buckwheat (Eriogonum prattenianum var. avium), Orcutt's quillwort (Isoetes orcuttii) and wildlife species such as Cooper's hawk (Accipiter cooperii) and several species of bats (Myotis spp). Slate Creek Area Adjacent to the southern boundary of the Hell's Half Acre (north of Grass Valley and south of Deer Creek) lies the Slate Creek area. This region supports serpentine soils and contains natural vegetation communities such as mixed serpentine chaparral, serpentine foothill pine chaparral woodland, northern interior (MacNab) cypress forest, and leather oak chaparral. According to Lonsdorf (1998), this is a possible location of Pine Hill flannelbush (Fremontodendron decumbens) and additional rare plants and butterflies. Because the northern edge of this site is adjacent to Hell's Half Acre, conservation opportunities are significant. Serpentine and Gabbro Soil Plant Communities North of Grass Valley near Highway 20, along Dorsey Drive/Hughes Road, is another local example of a serpentine soil inclusion community consisting of approximately 160 acres. Plant communities located in this region include mixed serpentine chaparral (Holland), serpentine foothill pine chaparral woodland, northern interior (MacNab) cypress forest, and leather oak chaparral. Also documented in this area is Sanborn's onion and an endemic butterfly species (Lonsdorf 1998). Several endemic plants are supported by locations such as American Ranch Hill/McCourtney Road Landfill/Wolf Mountain/Ponderosa Way. According to Lonsdorf (1998), this area is a conglomeration of gabbroic soil that contains a mixture of endemic species along with other foothill communities. These areas run southeasterly from east of Rough and Ready, north of Highway 20 and south to beyond Wolf Mountain. Vegetation communities include gabbroic northern mixed chaparral and northern interior (MacNab) cypress forest. Individual native species include Stebbin's morning-glory (Calysegia stebbinsii), Pine Hill flannelbush, Bacigalupi's perideridea (Perideridia bacigalupii), California horned lizard (Phrynosoma coronatum frontale) and foothill yellow-legged frogs. There is also a potential for additional rare plants and animals to be identified on site. Even though this is a large area with many existing roads, ranches, and the old County landfill, there are areas that still have high integrity. There is a potential for BLM land to be traded, allowing urban encroachment (Lonsdorf 1998). Union Hill Meadow Union Hill Meadow contains important elements of several ecosystems, which it shares with Empire Mine State Historic Park. The property contains perhaps the finest stand of madrone forest in California. The meadow is likely to be the best example of what the Grass Valley area looked like prior to early development. Few low elevation montane meadows remain intact, and this represents an ecosystem now rare in California. It is extremely diverse in native grasses and forbs, many of which are uncommon on a regional basis. According to a State report, it is the best example of natural grassland in the western Sierra Nevada (Barry, et al., California Department of Parks and Recreation, Ecological Assessment of the Meadow North of Union Hill, August 1, 1997). Wolf Creek Wolf Creek runs through the City of Grass Valley, and has undergone considerable channelization and augmentation. Prior to entering the city to the northeast and upon leaving to the south, it returns to its natural course. The Riverine habitat of Wolf Creek supports in-stream species, such as invertebrates, amphibians, and fish, including a resident fishery of rainbow trout, brown trout, and several warm-water fishes. The invertebrate population is typical for a trout stream and includes stonefly larvae, mayfly larvae, addisfly larvae, and aquatic snails. Canadian Geese Wintering Habitat This area is located southwest of the City of Grass Valley on the 130 acre Conway Ranch. It is a large open meadow that provides wintering habitat for migratory Canada geese. Currently, this area is not designated as Critical Habitat (Mary Moore, USFWS, pers. comm.). However, as the only wintering ground for such migratory waterfowl species in western Nevada County, it is an important part of the ecosystem. 3.3.2 Impacts Impact Evaluation Criteria: Section 21001 of the Public Resources Code, the California Environmental Quality Act (CEQA), states California's policies with respect to fish and wildlife, summarized as follows: Prevent the elimination of fish and wildlife species due to human activities. Ensure that fish and wildlife populations do not drop below self sustaining levels. Preserve representatives of all plant and animal communities for future generations. Section 15382 of CEQA defines a significant effect as: "Significant effect on the environment" means a substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic significance. Section 15065 of CEQA provides for mandatory findings of significance when: The project has the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish and wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of an endangered, rare or threatened species, or eliminate important examples of the major periods of California history or prehistory. Appendix G of the CEQA Guidelines contains the following criteria for determining the significance of biological resources impacts: Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service. Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or U.S. Fish and Wildlife Service. Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means. Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites. Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance. Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan. A "rare or endangered species", as defined in Section 15380 of the CEQA Guidelines, is "endangered" when its survival and reproduction in the wild are in immediate jeopardy from one or more causes, including loss of habitat, change in habitat, over-exploitation, predation, competition, disease, or other factors; or "rare" when, although not presently threatened with extinction, the species is existing in such small numbers throughout all or a significant portion of its range that it may become endangered if its environment worsens; or the species is likely to become endangered within the foreseeable future throughout all or a portion of its range, and may be considered "threatened" as that term is used in the Federal Endangered Species Act. The Federal Endangered Species Act (FESA) of 1973 (50 CFR 17) provides legal protection, and requires definition of critical habitat and development of recovery plans for plant and animal species in danger of extinction. California has similar mandates in the California Endangered Species Act (CESA) of 1984 and the California Native Plant Protection Act of 1977. These laws regulate the process by which plant or animal species are listed as endangered or threatened. Some species listed by the State are not necessarily protected by the federal protection agencies, therefore consultation with both the USFWS and the CDFG should occur when reviewing projects and their potential impacts to plants, wildlife, and their associated habitats. In addition to federal and state endangered and threatened listings, species may also be listed as a "species of concern" due to their limited distribution, declining populations, diminishing habitat, or unusual scientific, recreational, or educational value. These species are not afforded the same legal protection as listed species, but may be added to official lists in the future. There are two general categories for these special interest species: 1) candidates for official federal or state listing as threatened or endangered; and 2) species that are not candidates, but have been unofficially identified as species of special interest by private conservation organizations or local governments. Federal candidate species are assigned to one of two categories, depending on current knowledge about the species and its biological importance for listing. Federal Category 1 (FC1) includes candidate species for which the USFWS has sufficient biological information to support a proposal to list a species as endangered or threatened; and Federal Species of Concern (FSC) includes taxa for which existing information may warrant listing, but substantial biological information to support proposed listing is lacking. The CDFG, in conjunction with the California Native Plant Society (CNPS), have compiled a data base, called the California Natural Diversity Data Base (NDDB), which references California's rare and endangered plants and animals. Some plants listed by the CNPS may not be officially listed by the State, but many of these would still be protected by CEQA; and any impacts affecting these species and their immediate habitat would be considered significant. Section 9 of the Endangered Species Act prohibits the "taking" of listed species. If it is believed that a project will inadvertently harm, harass or collect a species, or that a species would suffer due to habitat modification, the USFWS must be consulted, and subsequent agency recommendations and permits must be obtained and adhered to. With respect to plants, Section 9 states that it is unlawful to import or export; remove and reduce to possession; deliver, receive, carry, transport, or ship; sell; or violate any regulation pertaining to such species or any threatened species of plants listed pursuant to the Act. If disruption of wetlands is to occur, a "no net loss" policy through the Clean Water Act must be adhered to, and contact with the U.S. Army Corps of Engineers (COE) permitting program for either a Nationwide Permit or a Section 404 permit may be required, the determination of which is based on actual acreage that would be affected. Disruption or loss of wetlands is a significant effect. A "Streambed Alteration Agreement", pursuant to CDFG Code Section 1600 et seq., must be made with the CDFG when a project will influence or divert the natural flow of a stream, substantially change its bed or bank, cross a stream bed, or utilize existing streambed materials. The CDFG is also involved in the Section 404 process by providing recommendations for mitigation measures. During the Section 1600 process, it may be decided that a Section 401 permit for water quality is required. Engaging in activities which may generate a need for a Streambed Alteration Agreement or Section 401 permit is a potentially significant effect. Impact #3.3-1: Approval of projects under the updated General Plan could reduce or destroy the habitat of species identified as sensitive, including species identified as endangered, candidate, and/or special status by the California Department of Fish and Game and U.S. Fish and Wildlife Service. This is a potentially significant impact. Discussion/Conclusion: Construction of projects under the General Plan and future roadway improvements could directly eliminate the habitat of species listed as endangered, candidate, and/or special status species by the California Department of Fish and Game and U.S. Fish and Wildlife Service. Consultation with the CDFG Natural Diversity Data Base (NDDB, 1997) revealed six sensitive species potentially located within the Grass Valley and Chicago Park USGS 7.5 minute quadrangles. This includes Stebbin's Morning Glory, Pine Hill Flannelbush, Red-anthered Rush, Follett's Monardella, Scadden Flat Checkerbloom and the California Horned Lizard. These species would be affected by a loss of habitat due to site grading, road building, infrastructure installation, and construction of residential, commercial and industrial development. Additionally, such development could result in the fragmentation of areas that currently consist of relatively undeveloped, uninterrupted wildlife habitat. Projects could otherwise indirectly impact such habitat through human intrusions, erosion, or invasive species. The General Plan addresses the potential for loss of habitat from future development by concentrating growth, thereby reducing the overall habitat loss and fragmentation that could occur if growth occurred in a more dispersed pattern. Specifically, Land Use goals and objectives promote infill as an alternative to peripheral expansion where feasible (2-LUG) and to ensure that future development proposals include full environmental review to assure minimization of environmental impacts (2-LUP). In addition, there are numerous goals, objectives, policies and implementation actions and strategies contained in the Conservation/Open Space Element developed to reduce potential impacts to habitat and endangered, candidate, sensitive and/or special status species. This includes preparing an inventory of sensitive environmental areas and features (1-COSO), the protection of rare and endangered animals and plants (3-COSO), encouragement of wildlife through habitat protection (5-COSO), and assurance of appropriate resource conservation and environmental protection measures as prerequisites to development (6-COSO). Although the General Plan defines goals, objectives, policies and implementation actions and strategies that will reduce potentially significant impacts to habitat and sensitive species, the Plan does not fully mitigate these potential impacts at the project level. The potential still exists for a substantial adverse effect through habitat modification on a species identified as endangered, candidate, or special status. Therefore, this will remain as a potentially significant impact but can be mitigated to a level that is less than significant. Impact #3.3-2: Approval of projects under the updated General Plan could impact wetland habitat (e.g. marsh, riparian and vernal pool). This impact is potentially significant. Discussion/Conclusion: Wetlands in Nevada County are generally small, isolated features dependent on riparian water. Construction of projects under the General Plan could directly eliminate wetland habitats or the introduction of non-native species. Indirect impacts can occur to wetlands due to development upgradient of such areas. Silt and other contaminants can be deposited in wetlands via drainage from construction sites and developed areas. The U.S. Army Corps of Engineers regulates the fill of wetlands under Section 404 of the federal Clean Water Act. The Department of Fish and Game recognizes wetlands for their critical value. Both agencies have policies of "no net loss" of wetlands. Therefore, the fill of significant wetland habitats associated with the 2020 General Plan land uses and future roadway and infrastructure improvements would be considered a significant impact. However, there are regulatory processes designed to identify and mitigate the loss of wetlands. The City of Grass Valley's Grading Ordinance will help mitigate these impacts, but should be reviewed to identify potential modifications to increase protection of downstream wetlands. The General Plan contains goals and objectives in the Conservation/Open Space Element to inventory sensitive environmental areas and features (1-COSO), protect, enhance and restore hydrologic features, including stream corridors, wetlands and riparian zones (2-COSG), and the protection of surface water quality (15-COSO). Although this impact is potentially significant, it can be mitigated to a level that is less than significant. Impact #3.3-3: Approval of projects under the updated General Plan could adversely affect movement and dispersal of wildlife and wildlife migration corridors. This could have a potentially significant impact. Discussion/Conclusion: Construction of projects under the General Plan could potentially create barriers to wildlife movement and dispersal and migration corridors. As an example, deer populations throughout the County have been characterized by both the California Department of Fish and Gand and the Tahoe National Forest as unstable and declining. Development in the western portion of the County and disruption of migration corridors are significant contributors to the decline. Factors such as fire suppression, road kills, subdivision and development of land, and harassment by dogs also relate to the decline (1995 Nevada County General Plan). There are regulatory processes designed to identify and mitigate potential impacts to the dispersal of wildlife and wildlife migration corridors that will be implemented at the project level. The City of Grass Valley's General Plan contains numerous land use goals and objectives to provide higher densities and infill development, which will help minimize impacts to wildlife corridors, as well as requiring adequate information when reviewing development proposals, including full environmental review to assure minimization of environmental impacts (2-LUP). Conservation and Open Space goals and objectives provide for the inventory of sensitive environmental areas and features (1-COSO), reduction of urban development impacts on native vegetation, wildlife and topography (4-COSO), encouragement of wildlife through habitat protection (5-COSO). The Conservation/Open Space Element also contains policies, objectives and implementation actions to prevent excessive alteration of the natural topography (6-COSP), develop and achieve agreement with the County of Nevada on a strategy for conservation and open space protection within the Grass Valley Planning Area (18-COSP), and to enlist the interest and efforts of appropriate state and federal agencies and private foundations regarding conservation and open space protection (19-COSP). Therefore, the goals, policies, objectives and implementation actions and strategies contained in the General Plan that will assist in mitigating this impact to a less than significant level. 3.3.3 Mitigation Measures The General Plan Update includes goals, objectives, policies and implementation actions and strategies which will substantially mitigate significant impacts to Biological Resources. These goals, objectives, policies and implementation actions and strategies are as follows:

1-COSG 13-COSG 4-COSI 1-COSO 14-COSO 9-COSI 2-COSO 10-COSP 10-COSI 3-COSO 2-COSP 14-COSI 4-COSO 3-COSP 15-COSI 5-COSO 4-COSP 10-CO 2-COSG 10-COSP 6-COSO 19-COSP 3-COSG 1-COSI 9-COSO 2-COSI 10-COSO 3-COSI 5-COSG 4-COSI

Implementation of these goals, objectives, policies and implementation actions and strategies along with the additional mitigation measures discussed below will ensure that any impacts to biological resources resulting from the 2020 General Plan Amendment will result in a less than significant impact Mitigation Measure #3.3-1: No net loss of habitat functions or values shall be caused by development where significant environmental features or significant habitat exist. No net loss shall be achieved through avoidance of the resource, or through creation or restoration of habitat of superior or comparably quality, in accordance with guidelines of the U.S. Fish and Wildlife Service and the California Department of Fish and Game (Applies to Impacts #3.3-1 and #3.3-2). Effectiveness of Measure: Implementation of this additional mitigation measure will ensure that any impacts to biological resources resulting from the 2020 General Plan Amendment will result in a less than significant impact Mitigation Measure #3.3-2: Review the City of Grass Valley's Grading Ordinance in order to incorporate measures designed to assure that downstream wetland and riparian areas are adequately protected from sedimentation, deposition and other adverse impacts resulting from upstream ground disturbance (Applies to Impact #3.3-2). Effectiveness of Measure: Regulations designed to assure that the effects of development do not impact downstream wetland and riparian areas will avoid loss of protected wetlands. Therefore, this is a less than significant impact. 3.4 AIR QUALITY The following information is taken from The City of Grass Valley General Plan Update Background Report, prepared by Quad Knopf and the Northern Sierra Air Quality Management District Annual Air Monitoring Report 1997, prepared by the Northern Sierra Air Quality Management District. 3.4.1 Setting Physical Setting The Grass Valley Planning Area lies within the Mountain Counties Air Basin, which includes Plumas County on the north and Mariposa County on the south. The Central Valley forms the western boundary and the Sierra Nevada Mountain Range forms the eastern boundary (refer to Figure 3.4-1). Air quality in the Planning Area is influenced not only by emissions from the Planning Area itself, but by emissions from upwind locations and regional climatic factors. Generally, the Planning Area has cool, wet winters and warm to hot summers. Winter storm systems from the Gulf of Alaska bring clean, cooler air and moisture. Due to its elevation of over 2,000 feet, the area is high above the winter fog that forms in the Central Valley, providing warmer sunny days between winter storm systems. Annual precipitation for Grass Valley is approximately 40 inches. January temperatures average between 40 and 45 degrees F. In the summer, the Planning Area is often affected by a dome of high pressure, and summer temperatures can exceed 100F. However, the "delta breeze," which frequently brings cooler ocean air in through the Carquinez Straits, can moderate these high temperatures. Predominant surface wind flow patterns for spring, summer, fall and winter are shown on Figures 3.4-2, 3.4-3, 3.4-4, and 3.4-5, respectively. Figure 3.4-3 illustrates the flow of air through the Carquinez Straits into the interior of the state during summer conditions. Air stagnation due to formation of surface and/or elevated inversions is common in the late summer and fall. Surface inversions are formed when cool air is trapped close to the surface by a layer of warm air above it. Elevated inversions occur when a layer of cool air is suspended between warm air layers above and below. Stagnation allows the concentration of air contaminants, subjecting persons in the region to elevated levels of pollution and consequential increased health risks. PM10 (particulate matter of 10 microns or less in diameter) and ozone are the primary pollutants of concern in the Planning Area. Residential open burning is the main contributor to PM10. The greatest ozone contributor is transported ozone from the Sacramento region and the Bay Area. However, motor vehicles are also a main local contributor to ozone. Carbon monoxide levels in the Planning Area have not been monitored since 1996. However, in the past years, levels of CO have not been significant. Regulatory Setting Both the federal and state governments establish air quality regulations. State standards, set through the California Air Resources Board (CARB), are generally more stringent than federal standards (Table 3.4-1). At the local government level, the Northern Sierra Air Quality Management District (NSAQMD) is responsible for planning and the maintenance/attainment of these standards. The California Clean Air Act (CCAA), passed in 1988 as AB 2595, requires local air pollution control districts to achieve and maintain both the federal and state ambient standards at the earliest practical date. For jurisdictions that have been classified as non-attainment for one or more pollutants, air quality attainment plans are to be prepared that either demonstrate attainment of the State ambient standards or provide a strategy for a five percent annual reduction in emissions of non-attainment pollutants in a given district. Although Nevada County is designated as attainment and/or unclassified by federal standards for PM10 and carbon monoxide (CO), it is classified according to California standards as a non-attainment area for ozone (O3) and PM10 and was designated as a federal nonattainment area for ozone in July, 1999. The attainment status of Nevada County for criteria pollutants under both state and federal standards as reported by the NSAQMD is shown in Table 3.4-2. A summary of air quality data (O3 and PM10) from the NSAQMD monitoring stations in Grass Valley from 1989 to 1997 is presented in Tables 3.4-3 and 3.4-4. The two Grass Valley monitoring stations are located at Litton Drive and Henderson Street. TABLE 3.4-1 AMBIENT AIR QUALITY STANDARDS

Pollutant Averaging Time California Standards National Standards2 Concen-tration3 Method4 Primary3,5 Secondary3,6 Method7 Ozone (O3) 1 Hour 0.09 ppm (180 µg./m3) Ultraviolet Photometry 0.12 gpm (235 µg./m3)8 Same as Primary Standard Ethylene Chemilumin-escence 8 Hour - 0.08 gpm (157 µg./m3) Respirable Particulate Matter (PM10) Annual Geometric Mean 30 µg./m3 Size Selective Inlet Sampler ARB Method P (8/22/85) - Same as Primary Standard Inertial Separation and Gravimetic Analysis 24 Hour 50 µg./m3 150 µg./m3 Annual Arithmetic Mean - 50 µg./m3 Fine Particulate Matter (PM2.5) 24 Hour No Separate State Standard 65 µg./m3 Same as Primary Standard Inertial Separation and Gravimetic Analysis Annual Arithmetic Mean 15 µg./m3 Carbon Monoxide (CO) 8 Hour 9.0 gpm (10 mg/m3) Non-dispersive Infrared Photometry (NDIR) 9 gpm (10 mg/m3) None Non-dispersive Infrared Photometry (NDIR) 1 Hour 20 gpm (23 mg/m3) 35 gpm (40 mg/m3) 8 Hour (Lake Tahoe) 6 gpm (7 mg/m3) - Nitrogen Dioxide (NO2) Annual Arithmetic Average - Gas Phase Chemilumin-escence 0.053 gpm (100 µg./m3) Same as Primary Standard Gas Phase Chemilumin-escence 1 Hour 0.25 gpm (470 µg./m3) - Lead 30 Day Average 1.5 µg./m3 AIHL Method 54 (12/74) Atomic Absorption - - High Volume Sampler and Atomic Absorption Calendar Quarter - 1.5 µg./m3 Same as Primary Standard Sulfur Dioxide Annual Arithmetic Mean - Fluorescence 0.030 gpm (80 µg./m3) - Pararosoaniline 24 Hour 0.04 gpm (105 µg./m3) 0.14 gpm (365 µg./m3) - 3 Hour - - 0.5 gpm (1300 µg./m3) 1 Hour 0.25 gpm (665 µg./m3) - - Visibility Reducing Particles 8 Hour (10 am to 6 pm, PST) In sufficient amount to produce an extinction coefficient of 0.23 per kilometer - visibility of ten miles or more (0.07-30 miles or more for Lake Tahoe) due to particles when the relative humidity is less than 70 percent. Method: ARB Method V (8/18/89). No Federal Standards Sulfates 24 Hour 25 µg./m3 Turbidimetric Barium Sulfate-AIHL Method 61 (2/76) Hydrogen Sulfide 1 Hour 0.03 gpm (42 µg./m3) Cadmium Hydroxide STRactan 1. California standards for ozone, carbon monoxide (except Lake Tahoe), sulfur dioxide (1 and 24 hour), nitrogen dioxide, suspended particulate matter - PM10, and visibility reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded. 2. National standards (other than ozone, particulate matter, and those based on annual averages or annual arithmetic mean) are not to be exceeded more than once a year. The ozone standard is attained when the fourth highest eight hour concentration in a year, averaged over three years, is equal to or less than the standard. For PM2,5, the 24 hour standard is attained when 98 percent of the daily concentrations, averaged over three years, are equal to or less than the standard. Contact U.S. EPA for further clarification and current federal policies. 3. Concentration expressed first in units n which it was promulgated. Equivalent units given in parenthesis are based upon a reference temperature of 25°C and a reference pressure of 760 mm of mercury. Most measurements of air quality are to be corrected to a reference temperature of 25°C and a reference pressure of 760 mm of mercury (1,013.2 millibar); gpm in this table refers to gpm by volume, or micro moles of pollutant per mole of gas. 4. Any equivalent procedure which can be shown to the satisfaction of the Air Resources Board to give equivalent results at or near the level of the air quality standard may be used. 5. National Primary Standards: the levels of air quality necessary, with an adequate margin of safety to protect the public health. 6. National Secondary Standards: the levels of air quality necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant. 7. Reference method as described by the EPA. An "equivalent method" of measurement may be used but must have a "consistent relationship to the reference method" and must be approved by the EPA. 8. New federal 8-hour ozone and fine particulate matter standards were promulgated by U.S. EPA on July 18, 1997. The federal 1-hour ozone standard continues to apply in areas that violated the standard. Contact U.S. EPA for further clarification and current federal policies. Source: State of California, Air Resources Board, April 9, 1998. TABLE 3.4-2 ATTAINMENT STATUS OF NEVADA COUNTY Pollutant Federal State Ozone Unclassified/Attainment* Non-Attainment Carbon Monoxide Unclassified/Attainment Unclassified Nitrogen Dioxide Unclassified/Attainment Attainment