4.8.1 Introduction Environmental Setting. Section 4.8 Hydrology and Water Quality. Regional. Climate. Fremont Valley Hydrologic Unit

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1 4.8.1 Introduction Section 4.8 Hydrology and Water Quality This section describes the affected environment and regulatory setting of the proposed project for hydrology and water quality and discusses mitigation measures to reduce impacts, where applicable. The information in this section is based on numerous available sources, as well as the Hydrology and Hydraulics Study (Appendix H) and Water Demand Analysis (Appendix I) prepared for the proposed project (AECOM, 2012c and 2012d) Environmental Setting Regional The project site is located in the northern region of the Mojave Desert Basin which is defined by surrounding mountain ranges that help create its generally dry conditions. The basin contains numerous mountain ranges that create valleys, closed drainage basins, salt pans, and seasonal saline lakes when precipitation is high enough. Most of the valleys are internally drained, resulting in a closed system where all precipitation that falls within the valley does not ever find its way to the ocean. The project site is located in the northern portion of Fremont Valley, a desert region that drains the eastern slopes of the Tehachapi Mountains, as well as the Sierra Nevada, El Paso and Rand Mountains. Within Fremont Valley, water generally flows east to Koehn Dry Lake, the lowest point topographically in the enclosed basin. Climate The climate of the Mojave Desert Basin is characterized by hot, dry summers and cold winters with relatively low annual precipitation. Average temperatures recorded in the Community of Mojave range from a low of 33º Fahrenheit (F) in December to highs of 98º F in July and August (Western Regional Climate Center, 2012). The local climate is typical of the high desert areas of California. Winter nights often drop below freezing, and snow is not unheard of. Table summarizes average temperatures and precipitation for the project vicinity. Fremont Valley Hydrologic Unit The project is located in the Fremont Valley Hydrologic Unit which drains the eastern slopes of the Tehachapi Mountains (AECOM, 2012c). The Fremont Valley Hydrologic Unit is part of the Lahontan region of the Regional Water Quality Control Board (RWQCB). Within Fremont Valley, water generally flows east towards Koehn Dry Lake, which is a closed basin where no waters drain toward the ocean

2 Table 4.8-1: Average Monthly Temperatures and Precipitation for the Antelope Valley, Kern County Station Elevation Average Maximum Temperature Average Minimum Temperature Average Annual Precipitation Mojave, CA (Coop ID ) 2,735 ft 75.8 F 49.9 F 5.93 in/yr Mojave 2 Ese, CA (Coop ID ) 2,680 ft 76.5 F 47.8 F 6.34 in/yr Source: Western Regional Climate Center, 2012 Local Surface Hydrology and Drainage The primary watercourse that intersects the project site is a dry wash, known as Pine Tree Creek Wash, which flows through the center of the property. Pine Tree Creek Wash is tributary to two different watersheds, Fremont Valley and Pine Tree Canyon. Pine Tree Canyon is a narrow mountain valley 17 miles in length, draining an area of 36 square miles. The canyon extends from the Tehachapi Mountains in the west to Fremont Valley in the east, dropping 4,000 feet in elevation from summit to desert floor. Rainfall is the greatest in the upper reaches of the watershed, which are at higher elevations than Fremont Valley. There is little existing development in the canyon, except for the Los Angeles Aqueduct at the east end and renewable energy projects in the west end near the summit. Fremont Valley is a broad desert valley 14 miles long, draining a 38-square-mile area. The primary watercourse runs parallel to SR 14, crossing the highway in a large culvert at about the center of the watershed. There is little development in the valley with the exception of existing residences north (downstream) of the project site. Union Pacific Railroad owns a rail spur that crosses the west half of the project site. When the spur was originally constructed in 1908, runoff that previously flowed overland to Pine Tree Creek Wash was channelized at a culvert, creating a secondary watercourse referred to as Railroad Culvert Wash. Subsequent construction of SR 14 west of the railroad further reduced the area tributary to the culvert by diverting runoff north of the project site through other culverts. Railroad Culvert Wash joins Pine Tree Creek Wash north of the project site. Floodplains According to the most recent Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map, a portion of Pine Tree Creek Wash is located within Zone A, which is defined by FEMA as a Special Flood Hazard Area (SFHA) subject to inundation by the one percent annual chance flood event, also known as a 100-year flood (Figure 4.8-1). This flood zone area generally runs through the center of the project site as a band 750 feet wide along the Pine Tree Creek Wash (AECOM, 2012c)

3 KERN COUNTY PLANNING AND COMMUNITY DEVELOPMENT DEPARTMENT BEACON PHOTOVOLTAIC PROJECT Feet Legend Plant Site State Waters FLOOD ZONE (KERN CO.) Area of Shallow Flooding Figure 4.8-1: FLOOD ZONE MAP Draft EIR June 2012

4 Soil Types and Erosion According to the NRCS mapping conducted for the countywide soil survey, the dominant soil types for the project site are Cajon loamy sand and Rosamond clay loam. Both of these soils are alluvial deposits derived from upland granite bedrock, but Cajon loamy sand allows for greater infiltration than Rosamond clay loam. The main channel in Fremont Valley is composed of Cajon loamy sand, while the alluvial fan to Barren Ridge is Arizo gravelly loam. Similar to Cajon loamy sand, Arizo gravelly loam consists of alluvium derived from granite and has good infiltration. Barren Ridge is mostly composed of Xeric Torriorthents, residuum weathered from igneous and metamorphic rock. The upper reaches of Pine Tree Canyon are composed of Xerolls, a mixed rock residuum. The downstream canyon walls are Jawbone gravelly loamy sand, residuum weathered from granite. The canyon floor contains mostly Arizo gravelly loam. Groundwater Hydrology The project site is located within the Fremont Valley Groundwater Basin north of the Antelope Valley Groundwater Basin, which underlies an extensive alluvial valley in the western Mojave Desert. The Fremont Valley Groundwater Basin encompasses 523 square miles and is bounded on the northwest by the Garlock fault zone at the base of the Tehachapi Mountains, and on the south by a southeastward-trending line that extends from the mouth of Oak Creek through Middle Butte to exposed bedrock near Gem Hill, which separates the Fremont Valley Groundwater Basin from the Antelope Valley Groundwater Basin (California Department of Water Resources (DWR), 2004). Water-bearing deposits of the Fremont Valley consist of both alluvium and lacustrine (lake) deposits. The alluvium is the most important water-bearing material in the basin. Alluvium is 1,190 feet thick along the margin of the basin and thins toward the middle of the basin, where it is interbedded with thick layers of lacustrine silt and clay near Koehn Lake. Groundwater in the alluvium is generally unconfined, although locally confined conditions occur near Koehn Lake (DWR, 2004). Groundwater in this arid, high desert region within Kern County is generally encountered relatively deep. The depth to groundwater below the site, measured in October 2007 from onsite wells, ranged from 210 to 436 feet below ground surface (bgs) (AECOM, 2012d). Recharge of the Fremont Valley Groundwater Basin is primarily accomplished by perennial runoff from the surrounding mountains and hills. Most recharge occurs at the foot of the mountains and hills by percolation through the head of nearby alluvial fan systems. Natural recharge of the basin includes percolation of ephemeral streams with the general groundwater flow direction being toward Koehn Lake at the center of the valley. There is no appreciable quantity of groundwater flowing out of the basin. The Koehn subbasin is bounded to the east and southeast by the Randsburg-Mojave Fault and Rand Mountains; to the northwest by the El Paso Mountains; to the west by the Sierra Nevada Mountains and the Garlock East Fault (or Cantil Fault); and to the northeast by the confluence of the El Paso and Rand Mountains. The Koehn subbasin has a closed surface drainage, whereby surface water does not exit the basin but flows from the surrounding mountains to Koehn Dry Lake. The South Lahontan Regional Water Quality Control Board (RWQCB) Basin Plan designates the groundwater in the Fremont Valley Groundwater Basin, which includes the Koehn Sub-basin, as having the following beneficial uses: municipal, domestic, agricultural, industrial, and freshwater replenishment. Water users in the Koehn Sub-basin derive their supplies singularly from groundwater resources. California City, located in the adjacent California City Sub-basin, uses both groundwater and water provided from the State Water Project (SWP) through the Antelope Valley East Kern Water District 4.8 4

5 (AVEK) (AECOM 2008). AVEK does not supply water north of California City to residences within the Koehn Sub-basin. There is no Urban Water Management Plan or groundwater management plan covering the Project site, nor is there a public water purveyor that can provide the Project with water from a practical standpoint. Groundwater is the most practical source of water supply in the Koehn Sub-basin of the greater Fremont Valley Groundwater Basin Regulatory Setting Federal Clean Water Act (CWA) Regulatory authorities exist on both the state and federal levels for the control of water quality in California. The USEPA is the federal agency, governed by the CWA, responsible for water quality management. The purpose of the CWA is to protect and maintain the quality and integrity of the nation s waters by requiring states to develop and implement state water plans and policies. Section 303 of the CWA requires states to establish water quality standards consisting of designated beneficial uses of water bodies and water quality standards to protect those uses for all Waters of the United States. Under Section 303(d) of the CWA, states, territories, and authorized tribes are required to develop lists of impaired waters. Impaired waters are the waters that do not meet water quality standards, even after point sources of pollution have installed the minimum required levels of pollution control technology. The law requires that these jurisdictions establish priority rankings for water on the lists and develop action plans to improve water quality. This process includes development of Total Maximum Daily Loads (TMDL) that set discharge limits for non-point source pollutants. The recently passed Ducheny Bill (AB 1740) requires the State Water Resources Control Board (SWRCB) and its nine Regional Water Quality Control Boards (RWQCBs) to post this list and to provide an estimated completion date for each TMDL. National Flood Insurance Program (NFIP) FEMA is responsible for managing the NFIP, which makes federally backed flood insurance available for communities that agree to adopt and enforce floodplain management ordinances to reduce future flood damage. The NFIP, established in 1968 under the National Flood Insurance Act, requires that participating communities adopt certain minimum floodplain management standards, including restrictions on new development in designated floodways, a requirement that new structures in the 100-year flood zone be elevated to or above the 100-year flood level (known as base flood elevation), and a requirement that subdivisions be designed to minimize exposure to flood hazards. To facilitate identifying areas with flood potential, FEMA has developed Flood Insurance Rate Maps that can be used for planning purposes, including floodplain management, flood insurance, and enforcement of mandatory flood insurance purchase requirements. Kern County is a participating jurisdiction in the NFIP and, therefore, all new development must comply with the minimum requirements of the NFIP

6 National Pollutant Discharge Elimination System (NPDES) Section 402 of the CWA regulates construction-related stormwater discharges to surface waters through the NPDES program, administered by the EPA with implementation authority delegated to the SWRCB, in California. An NPDES permit is required for all projects that disturb one or more acre of land. Therefore, the proposed project would require an NPDES permit from the Lahontan RWQCB. As part of the permitting effort, the project operator would be required to file a public Notice of Intent (NOI), to discharge stormwater associated with the project. As part of the NPDES program, the project operator would be required to develop a Storm Water Pollution Prevention Plan (SWPPP), which would include best management practices (BMPs) to be implemented to prevent soil erosion and discharge of other construction-related pollutants that could contaminate nearby surface waters. Permittees are further required to conduct annual monitoring and reporting to ensure that BMPs are correctly implemented and effective in controlling the discharge of stormwater-related pollutants. The SWPPP and all associated BMPs must meet the requirements of the NPDES General Permit for construction stormwater discharge (see below). State Department of Water Resources DWR s major responsibilities include preparing and updating the California Water Plan to guide development and management of the state s water resources; planning, designing, constructing, operating, and maintaining the State Water Resources Development System; regulating dams; providing flood protection; assisting in emergency management to safeguard life and property; educating the public; and serving local water needs by providing technical assistance. In addition, DWR cooperates with local agencies on water resources investigations; supports watershed and river restoration programs; encourages water conservation; explores conjunctive use of ground and surface water; facilitates voluntary water transfers; and, when needed, operates a state drought water bank. Porter Cologne Water Quality Control Act The Porter-Cologne Water Quality Control Act (Water Code Sections et seq.), passed in 1969, requires protection of water quality by appropriate design, sizing, and construction of erosion and sediment controls. The Porter-Cologne Act established the SWRCB and divided California into nine regions, each overseen by a RWQCB. The SWRCB is the primary state agency responsible for protecting the quality of the state s surface and groundwater supplies and has delegated primary implementation authority to the nine RWQCBs. The Porter-Cologne Act assigns responsibility for implementing CWA Sections 401 through 402 and 303(d) to the SWRCB and the nine RWQCBs. The Porter-Cologne Act requires the development and periodic review of water quality control plans (Basin Plans) that designate beneficial uses of California s major rivers and groundwater basins and establish narrative and numerical water quality objectives for those waters, provide the technical basis for determining waste discharge requirements, identify enforcement actions, and evaluate clean water grant proposals. The basin plans are updated every three years. Compliance with basin plans is primarily achieved through implementation of the NPDES, which regulates waste discharges as discussed above. The project site is located within the jurisdiction of the Lahontan RWQCB- Region 6. The Basin Plan for the Lahontan region defines a variety of water quality objectives for the Fremont-Antelope Hydrologic Units

7 California Water Code 10912/ SB 267 SB 267 amends Section of the Water Code relating to water, and exempts a proposed photovoltaic or wind energy generation facility from preparing a Water Supply Assessment if the facility would demand no more than 75 acre-feet of water annually. California Water Code Section California Water Code Section requires that any person discharging waste or proposing to discharge waste that could affect the quality of the waters of the state, other than into a community sewer system, must submit a report of waste discharge to the applicable RWQCB. Any actions related to the proposed project that would be applicable to California Water Code Section will be reported to Lahontan RWQCB. Statewide General NPDES Permit for Construction Activity The State of California adopted a new Construction General Permit on September 2, SWRCB Water Quality Order DWQ (Construction General Permit) regulates construction site stormwater management. Dischargers whose projects disturb one or more acres of soil, or whose projects disturb less than one acre but are part of a larger common plan of development that in total disturbs one or more acres, are required to obtain coverage under the general permit for discharges of stormwater associated with construction activity. Construction activity subject to this permit includes clearing, grading, and disturbances to the ground, such as stockpiling or excavation, but does not include regular maintenance activities performed to restore the original line, grade, or capacity of the facility. To obtain coverage under this permit, project operators must electronically file Permit Registration Documents, which include a Notice of Intent, a SWPPP, and other compliance-related documents. An appropriate permit fee must also be mailed to SWRCB. The SWPPP identifies BMPs that must be implemented to reduce construction effects on receiving water quality based on potential pollutants. The BMPs identified are directed at implementing both sediment and erosion control measures and other measures to control potential chemical contaminants. The SWPPP also includes descriptions of the BMPs to reduce pollutants in stormwater discharges after all construction phases have been completed at the site (post-construction BMPs). The permit includes several new requirements (as compared to the previous Construction General Permit, DWQ), including risk-level assessment for construction sites, an active stormwater effluent monitoring and reporting program during construction (for risk level II and III sites), rain event action plans for certain higher risk sites, and numeric effluent limitations and numeric action levels for ph and turbidity as well as requirements for qualified professionals that prepare and implement the plan. The permit became effective July 1, Local Kern County General Plan The policies, goals, and implementation measures in the Kern County General Plan for hydrology and water resources applicable to the project are provided below. The Kern County General Plan contains additional policies, goals, and implementation measures that are more general in nature and are not specific to 4.8 7

8 development such as the proposed project. Therefore, these policies are not listed below, but all policies, goals, and implementation measures in the Kern County General Plan are incorporated by reference. Land Use, Open Space, and Conservation Element 1.3 Physical and Environmental Constraints Policies Policy 1: Policy 2: Policy 3: Policy 7: Policy 8: Policy 9: Kern County will ensure that new developments will not be sited on land that is physically or environmentally constrained (Map Code 2.1 [Seismic Hazard], Map Code 2.2 [Landslide], Map Code 2.3 [Shallow Groundwater], Map Code 2.5 [Flood Hazard], Map Codes from , Map Code 2.10 [Nearby Waste Facility], and Map Code 2.11 [Burn Dump Hazard]) to support such development unless appropriate studies establish that such development will not result in unmitigated significant impact. In order to minimize risk to Kern County residents and their property, new development will not be permitted in hazard areas in the absence of implementing ordinance and programs. The ordinances will establish conditions, criteria and standards for the approval of development in hazard areas. Zoning and other land use controls will be used to regulate and, in some instances, prohibit development in hazardous areas. Ensure effective slope stability, wastewater drainage, and sewage treatments in areas with steep slopes are adequate for development. Encourage the preservation of the floodplain s flow conveyance capacity, especially in floodways, to be open space/passive recreation areas throughout the County. Construction of structures that impede water flow in a primary floodplain will be discouraged. Policy 10: The County will allow lands which are within flood hazard areas, other than primary floodplains, to be developed in accordance with the General Plan and Floodplain Management Ordinance, if mitigation measures are incorporated so as to ensure that the proposed development will not be hazardous within the requirements of the Safety Element (Chapter 4) of this General Plan. Policy 11: Implementation Measures Protect and maintain watershed integrity within Kern County. Measure D: Review and revise the County s current Grading Ordinance as needed to ensure that its standards minimize permitted topographic alteration and soil erosion while maintaining soil stability. Measure E: Development proposed in areas with steep slopes will be reviewed for conformity to the adopted Hillside Development Ordinance to ensure that appropriate soil stability, drainage, and sewage treatment will result. Measure F: The County will comply with the Colbey-Alquist Floodplain Management Act in regulating land use within designated floodways

9 Measure H: Development within areas subject to flooding, as defined by the appropriate agency, will require necessary flood evaluations and studies. Measure I: Designated flood channels and water courses, such as creeks, gullies, and riverbeds, will be preserved as resource management areas or in the case of urban areas, as linear parks whenever practical. Measure J: Compliance with the Floodplain Management Ordinance prior to grading or improvement of land for development or the construction, expansion, conversion or substantial improvements of a structure is required. Measure N Applicants for new discretionary development should consult with the appropriate Resource Conservation District and the California Regional Water Quality Control Board regarding soil disturbances issues. 1.9 Resources Policies Policy 11: Minimize the alteration of natural drainage areas. Require development plans to include necessary mitigation to stabilize runoff and silt deposition through utilization of grading and flood protection ordinances General Provisions Surface Water and Groundwater Policies Policy 34: Ensure that water quality standards are met for existing users and future development. Policy 40: Encourage utilization of community water systems rather than the reliance on individual wells. Policy 41: Review development proposals to ensure adequate water is available to accommodate projected growth. Policy 43: Drainage shall conform to the Kern County Development Standards and the Grading Ordinance. Policy 44: Policy 46: Discretionary projects shall analyze watershed impacts and mitigate for construction-related and urban pollutants, as well as alterations of flow patterns and introduction of impervious surfaces as required by the California Environmental Quality Act (CEQA), to prevent the degradation of the watershed to the extent practical. In accordance with the Kern County Development Standards, tank truck hauling of domestic water for land developments or lots within new land developments is not permitted. Implementation Measures Measure Y: Promote efficient water use by utilizing measures such as: (i) Requiring water-conserving design and equipment in new construction; (ii) Encouraging water-conserving landscaping and irrigation methods; and (iii) Encouraging the retrofitting of existing development with water conserving devices

10 Kern County Zoning Ordinance Chapter Floodplain Combining District Section prohibits the following uses in the Floodplain Combining District, as applicable to the proposed project: A. All uses that will likely increase the flood hazard or affect the water-carrying capacity of the floodplain beyond the limits resulting from encroachment as specified in Section B. All uses that will likely increase the flood hazard or affect the water-carrying capacity of the floodplain beyond the limits resulting from encroachment as specified in Section of this chapter. C. Dumping, stockpiling, or storage of floatable substances or other materials which, in the opinion of the Kern County and Survey Services Department, will add to the debris loads of the stream or watercourse, unless protected by flood control devices approved by the Kern County Engineering and Survey Services Department and constructed in accordance with Section D. Storage of junk or salvage operations. E. Oil storage tanks or processing equipment, unless flood-proofed or sufficiently elevated above the Base Flood Elevation, as determined by the Kern County Engineering and Survey Services Department. F. Individual sewage disposal systems (e.g., septic tank systems), unless protected by flood control devices approved by the Kern County Engineering and Survey Services Department and constructed in accordance with the requirements of the Kern County Health Department so as to minimize infiltration of floodwaters into the systems and discharges from the systems into the floodwaters. G. Sources of water supply (e.g., wells, springs) unless protected by flood control devices approved by the Kern County Engineering and Survey Services Department and constructed in accordance with the requirements of the Kern County Health Department so as to minimize infiltration of floodwaters. Kern County Grading Ordinance (17.28) Requirements of the Kern County Grading Ordinance will be implemented. Of particular note with respect to hydrology and water quality is Section , Erosion Control. Kern County Floodplain Management Ordinance (17.48) Any construction that takes place within areas of special flood hazards, areas of flood-related erosion hazards, and areas of mudslide (i.e., mudflow) hazards within the jurisdiction of unincorporated Kern County will comply with the requirements and construction design specifications of this ordinance. Any required development permits will be obtained prior to commencement of construction activities. Sections through of the ordinance elaborate on the standards of construction in the special flood hazards area

11 4.8.4 Impacts and Mitigation Measures Methodology This section analyzes impacts on hydrology and water quality from the implementation of the proposed project, based on changes to the environmental setting as described above. Surface waters at the project site were identified by reviewing the Hydrology and Hydraulics study (Appendix H) and Water Demand Analysis (Appendix I) prepared for the proposed project (AECOM, 2012c and 2012d). Thresholds of Significance The Kern County CEQA Implementation Document and Kern County Environmental Checklist identify the following criteria, as established in Appendix G of the CEQA Guidelines, to determine if a project could potentially have a significant adverse effect on hydrology and water quality. A project could have a have a significant adverse effect on hydrology and water quality if it: Violates any water quality standards or waste discharge requirements; Substantially depletes groundwater supplies or interferes 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 alters the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner that would result in substantial erosion or siltation on-site or off-site; Substantially alters 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 that would result in flooding on-site or off-site; Creates or contributes runoff water that would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; Otherwise substantially degrades water quality; Places housing within a 100-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map; Places within a 100-year hazard area structures that would impede or redirect flood flows; Exposes people or structures to a significant risk of loss, injury, or death involving flooding, including flooding as a result of the failure of a levee or dam; or Contributes to inundation by seiche, tsunami, or mudflow. The lead agency determined in the NOP/IS (see Appendix A) that the following environmental issue areas resulted in no impact or less-than-significant impact and were scoped out of requiring further review in this draft EIR. Please refer to Appendix A of this draft EIR for a copy of the NOP/IS and additional information regarding these issue areas:. Places housing within a 100-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map;

12 Exposes people or structures to a significant risk of loss, injury, or death involving flooding, including flooding as a result of the failure of a levee or dam; and Contributes to inundation by seiche, tsunami, or mudflow. Project Impacts Impact 4.8 1: The project would violate water quality standards or waste discharge requirements. Construction The site is relatively flat, with only a modest potential for runoff. This condition would not change with construction of the proposed project, which would include the following: grading for access roads; stationary ground-mounted PV module foundations; inverters and transformers; installation of an operations and maintenance building, an 8-foot security fence; and the material laydown and equipment staging areas. Minimal grading and excavation would be required for required foundations at the sites; however, grading and excavation could affect drainage on the project site. Careful design of access road gradients and other project features, such as the inverter pads, would prevent substantial alterations to drainage patterns and/or erosion within the project site. The amount of impervious surface would be about eight acres, which represents 0.4 percent of the total site. Potential impacts on water quality arising from erosion and sedimentation are expected to be localized and temporary during construction; construction activities would exceed the one-acre threshold of ground disturbance that would require adherence to the NPDES General Construction Permit. As part of the NPDES program, the project operator would be required to develop a SWPPP, which would include BMPs to be implemented to prevent soil erosion and discharge of other construction-related pollutants that could contaminate nearby drainages. In addition, prior to the commencement of construction activities, the project operator would be required to adhere to the requirements of the Kern County Grading Ordinance. These requirements include preparation and submittal of a SWPPP to the Kern County Engineering, Surveying, and Permit Services Department, which would identify all areas of potential construction pollutant migration off-site, and would specify the design of BMPs to minimize potential erosion and sedimentation impacts. Construction would not otherwise involve any discharge of wastes. Additionally, as indicated on the proposed site plan, jurisdictional extent of the wash will be avoided entirely except for three Arizona-style crossings needed to access the eastern side of the facility and placement of perimeter fencing. The total impact will be minimal from these crossings and will comply with all pertinent regulations. A buffer has also been included around jurisdictional waters. The development has avoided putting any panels or solar facility structures within high-flow areas as determined in the hydrology study for the 100-year event, and is separate and in addition to avoidance of the Pine Tree Creek wash. Therefore, with adherence to all existing regulations regarding erosion and site drainage, construction of the proposed project would not violate water quality standards or waste discharge requirements. During construction or operation and maintenance of the proposed project, any activity which results in the accidental release of hazardous or potentially hazardous materials could result in water quality degradation. Materials that could contribute to this impact include but are not limited to the following: diesel fuel, gasoline, lubricant oils, hydraulic fluid, antifreeze, transmission fluid, lubricant grease, cement slurry, and other fluids utilized by construction and maintenance vehicles and equipment. Motorized

13 equipment could leak hazardous materials such as motor oil, transmission fluid, or antifreeze due to inadequate or improper maintenance, unnoticed or unrepaired damage, improper refueling, or operator error. As noted in Section 4.7, Hazards and Hazardous Materials, MM would require the project operator to provide a Hazardous Materials Business Plan that would delineate hazardous material and hazardous waste storage areas; describe proper handling, storage, transport, and disposal techniques; describe methods to be used to avoid spills and minimize impacts in the event of a spill; describe procedures for handling and disposing of unanticipated hazardous materials encountered during construction; and establish public and agency notification procedures for spills and other emergencies, including fires. The project operator shall provide the hazardous materials business plan to all contractors working on the project and shall ensure that one copy is available at the project site at all times. Discharge of water used during construction would be regulated under the NPDES General Permit for Discharges of Storm Water Associated with Construction Activity (Construction General Permit) required by the RWQCB. Compliance with the conditions of the NPDES General Permit would ensure that contaminated groundwater is properly tested and treated, if necessary, prior to discharge to any surface water. During construction of the proposed project, potential impacts to water quality associated with erosion and sedimentation would be localized and temporary. The project operator would implement measures to minimize and contain erosion and sedimentation in accordance with the Kern County Grading Code, and implement Mitigation Measures MM 4.7-1, MM 4.8-1, and MM prior to commencement of any ground disturbance activities. Operation The use of vehicles and other motorized equipment during operations and maintenance could result in the accidental release of diesel fuel, gasoline, lubricant oils, hydraulic fluid, antifreeze, transmission fluid, and lubricant grease. Lubricants and hydraulic fluids would also be potentially harmful or hazardous if a release were to occur during replacement of the fluids, as required per normal maintenance. In contrast with construction activities, which would include more intensive use of heavy equipment for longer periods of time, operation and maintenance of the proposed project would have substantially less potential to result in an accidental spill or release of hazardous materials that could cause water quality degradation. The site engineering and design plans for the proposed project would be required to comply with the requirements of the Kern County Code of Building Regulations, as well as with Kern County Development Standards and Floodplain Management Ordinance. As noted in the Hydrology Study (AECOM 2012c), final site design will include the slight elevation of internal roadways where needed to control water flow. Prior to the commencement of construction activities, the project operator would be required to prepare and submit a drainage plan to the Kern County Engineering, Surveying, and Permit Services Department, which would include post-construction structural and nonstructural BMPs. Routine structural BMPs are intended to address water quality impacts related to drainage that are inherent in development. Examples of routine structural BMPs include filtration, runoff-minimizing landscape for common areas, energy dissipaters, inlet trash racks, and water quality inlets. Therefore, long-term impacts on drainage patterns that could result in substantial erosion and siltation on-site or off-site would be less than significant after implementation of MM and MM and BMPs required by the Kern County Grading Code and Floodplain Management Ordinance

14 Mitigation Measures MM 4.8-1: Prior to issuance of a grading permit, the project operator shall submit a Stormwater Pollution Prevention Plan and applicable permits shall be obtained from the Lahontan Regional Water Quality Control Board (RWQCB) for the project to the Kern County Planning and Community Development Department that specifies best management practices to prevent all construction pollutants from contacting stormwater, with the intent of keeping sedimentation or any other pollutants from moving offsite and into receiving waters. The requirements of the Stormwater Pollution Prevention Plan shall be incorporated into design specifications and construction contracts. Recommended best management practices for the construction phase may include the following: Stockpiling and disposing of demolition debris, concrete, and soil properly; Installation of a stabilized construction entrance/exit and stabilization of disturbed areas; Implementing erosion controls; Properly managing construction materials; Proper protections for fueling and maintenance of equipment and vehicles; and Managing waste, aggressively controlling litter, and implementing sediment controls. MM 4.8-2: Prior to issuance of a grading permit, the project operator shall prepare a drainage plan that is designed to minimize runoff and surface water pollution and will include engineering recommendations to minimize the potential for impeding or redirecting 100-year flood flows. The final design of the solar arrays shall include a one-foot of freeboard clearance above the calculated maximum flood depths for the solar arrays of the finished floor of any permanent structures. Solar panel sites shall be graded to direct potential flood waters into channels adjacent to the existing and proposed right of ways without increasing the water surface elevations more than one foot or as required by Kern County s Floodplain Ordinance. The drainage plan shall be prepared in accordance with the Kern County Grading Code and approved by the Kern County Engineering, Surveying and Permit Services Department, Floodplain Management Section prior to the issuance of grading permits. Implement Mitigation Measure MM Level of Significance after Mitigation Less than significant. Impact 4.8 2: The project would 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. Table Proposed Water Demand for Annual Water Demand (AFY) Period of Performance Total (AF) Construction months 304 Operation years 450 Total 32-year period 754 Source: AECOM, 2012d AF = acre-feet; AFY = acre-feet per year

15 According to the Water Demand Analysis (AECOM, 2012d) groundwater within the Koehn Sub-basin flows north-northeast toward the Koehn Dry Lake, the area of lowest altitude in the Fremont Valley. The Koehn Sub-basin is considered a closed basin; the only natural mechanism for water to exit is through evaporation at Koehn Dry Lake. Groundwater in the Koehn Sub-basin is reportedly under generally unconfined conditions, except in the vicinity of Koehn Dry Lake, where lacustrine deposits locally create confined conditions. The depth to groundwater below the site, measured in October 2007 from on-site wells, ranged from 210 to 436 feet bgs. Since the mid-1980s, as agricultural operations have substantially curtailed, water levels have recovered in the Koehn Sub-basin. A review of satellite images (2008) and a field survey of the area confirm that only about 136 acres are presently being used for agriculture in the Koehn Sub-basin (AECOM, 2008). Since about 1986, and with the significant reduction in agricultural operations, groundwater levels have recovered between 100 and 130 feet in wells located within the vicinity of the Project site. This reflects changes in storage as water moves into the depression caused by the over pumping, and also reflects a positive water balance and the reversal of the prior trend, as recharge exceeds discharge in the Koehn Sub-basin. More recently, a review of the USGS National Water Information System (NWIS) database updated through 2011 shows that water levels since 2007 have continued to recover in the area of the Project site. The USGS monitor well located in the center of the Project site shows an increase in the water level of about eight feet since 2007 or about two feet per year since 2007, indicating the Koehn Subbasin is continuing to recover in response to significantly reduced pumping. Construction Temporary construction activity would require the use of water for a variety of activities such as grading and hydro-consolidation of soils, dust control, street sweeping, cleaning of construction equipment, and other general use. As noted in Table 4.8-2, the water demand for facility construction would consist of 304 acre-feet over a 22-month construction period (or about 166 acre-feet per year [AFY]) (AECOM, 2012d). This demand equates to a projected pump rate during construction of about 103 gallons per minute (gpm), assuming pump operation of 24 hours per day for 22 months, which is a conservative overestimation of actual water usage on the project site. There is no Urban Water Management Plan or groundwater management plan covering the project site, and there are limited options for public water purveyor sources that can provide the project with water (AECOM, 2012d). Water supplies for construction would be obtained through the use of the existing 12 groundwater supply wells at the project site. The wells were originally designated as agricultural supply wells, but they have been reclassified as inactive and out-of-service by Kern County and will be reclassified as appropriate for use by the project operator. An analysis of natural infiltration to the aquifer from precipitation using updated digital elevation maps and precipitation data for the area was performed in 2008 to provide estimates of recharge to the Koehn subbasin. From this update, runoff from the surrounding mountains in the Koehn subbasin was estimated to be 22,000 AFY (AECOM, 2012d). Using estimates from various sources on the percentage of runoff within the subbasin that is recharged to the groundwater basin (between 15 percent and 100 percent), recharge rates were estimated at between 3,300 and 22,000 AFY. An estimate of annual recharge using recovery rates of about 9,000 AFY for the area southwest of Koehn Lake fits within this range and is similar to the value proposed by others for the Koehn subbasin who assumed that 50 percent of the runoff or about 11,000 AFY would become recharge. Based on the water demand analysis, the proposed project

16 annual construction water usage of 166 AFY represents approximately 1.1 to 1.8 percent of this estimated annual recovery volume. Construction would not prevent or inhibit any incidental groundwater recharge that may occur on site during precipitation events as the project site would generally remain entirely pervious during construction.therefore, considering the temporary nature of the water supply needs combined with the relatively small percentage of water needed compared to what is naturally recharging into the basin, the potential impact to groundwater supplies would be less than significant. Operation After the solar facility is constructed, the annual water demand for facility operation would drop significantly. Water use is required for washing the solar photovoltaic (PV) panels, with a minor amount of water use for sanitary requirements at the O&M building. Water is necessary to remove dust and debris to maintain efficient panel operation. The cleaning interval would be determined by the rate at which electrical output degrades between cleanings. Projected water use during the operational phase is estimated to be about 15 AFY in support of potable supply and periodic cleaning of PV panels. During operation, the pumping rate to provide water would average 10 gpm. Over the 30-year projected life of the facility, the operational water demand would constitute a total of 450 AF. The operational water demand of 15 AFY is inclusive of drinking (potable) water demand for workers on-site, which is estimated to be 3,000 to 5,000 gallons per month (about 0.11 to 0.18 AFY). The operational supply of 15 AFY is significantly less, about 0.10 to 0.17 percent of the estimated annual recharge to the Koehn subbasin. Once construction is complete, the total amount of new impervious surfaces for the site would be eight acres or 0.4 percent of the total site area. The new impervious surfaces that would result from the proposed project would be limited to the O&M building and associated parking, support foundations for the solar equipment and storage buildings. Improved roads would be located throughout the project site to provide access to the solar equipment but would be constructed of earthern or gravel materials which are pervious. Thus, project operations would not substantially alter groundwater infiltration rates associated with precipitation. However, the ratio of impervious to pervious surfaces would be very small (0.4 percent) and would have negligible effect on recharge and underlying groundwater levels. Therefore, operation of the proposed project would have a less-than-significant impact on groundwater supplies. Mitigation Measures No mitigation measures are required. Level of Significance Impacts would be less than significant

17 Impact 4.8 3: The project would substantially alter the existing drainage patterns of the site or area, including through the alteration of the course of a stream or river, in a manner than would result in substantial erosion on site or off site. Construction As discussed in Section 4.5 Geology and Soils, Impact 4.5-4, because of the relatively flat topography of the property, the proposed project would involve minimal site grading, with removal of vegetation for installation of the PV panel structures, and implementation of Mitigation Measures MM would reduce construction-related soil erosion impacts to less-than-significant levels. As discussed for Impact 4.8-1, site preparation activities for the construction of the proposed improvements would include some minor grading activities that would disturb surface soils. During rainfall events, and particularly during construction activities when surface soils are exposed, there is the possibility of significant surface erosion and off-site sediment transportation. However, as outlined in MM 4.8-2, prior to the commencement of construction activities, the project operator would be required to prepare and submit a SWPPP to the Kern County Engineering, Surveying, and Permit Services Department. The SWPPP would identify all areas of potential construction pollutant migration off-site, and would specify the design of BMPs to minimize potential erosion and sedimentation impacts. Therefore, with adherence to all existing regulations regarding erosion and site drainage, the proposed project would not result in substantial erosion on- or off-site. Impacts would be less than significant and no mitigation is required. Construction, operation, and maintenance of the proposed project would not permanently alter the course of any drainage, or substantially alter drainage patterns on or off the project site. In addition, as discussed above under Impact 4.8-1, construction-related erosion and sedimentation as a result of soil disturbance would be less than significant with implementation of BMPs required by the Kern County Grading Code and Floodplain Management Ordinance, and compliance with the NPDES General Permit. Operation The project site is currently undeveloped and the proposed project improvements would alter the drainage patterns through the placement of the solar arrays and the construction of concrete pads for the substation and operation and maintenance building. During rainfall events there is the possibility of significant surface erosion and off-site sediment transport in stormwater runoff. However, the proposed project s site engineering and design plans would be required to comply with the most recent requirements of the Kern County Code of Building Regulations, as well as with Kern County Development Standards. Furthermore, all site drainage plans would be required to comply with Division Four of the Kern County Development Standards, which establish guidelines including, but not limited to, site development standards and mitigation, flood control requirements, erosion control, and on-site drainage flow requirements. Therefore, with adherence to all existing regulations regarding erosion and site drainage, the proposed project would neither alter the course of a stream or river nor result in substantial erosion on- or off-site. Impacts would be less than significant and no mitigation is required. Mitigation Measures Implement Mitigation Measures MM 4.5-2, 4.7-1, MM 4.8-1, and MM