31B - CUP - 1901 NORTH FAIRVIEW ST

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City of Santa Ana Environmental Checklist Would the project: a. Violate any water quality standards or waste discharge requirements? Less- than - Significant Impact. The proposed project could potentially result in impacts to water quality from both construction and operation, which are discussed separately below. Watersheds are typically areas that drain to a single point or receiving water (any watercourse or wetland into which surface water flows). The project site is located in the Santa Ana River watershed which is underlain by the southwest portion of tine Coastal Plain of Orange County Groundwater Basin. The project site is located at approximately 40 feet above mean sea level on flat terrain that slopes gently downward to the south - southwest (Athanor 2011x). The project site is drained generally by water sheet flows over asphalt -paved surfaces into the existing stormwater drainage system, which discharges into the Santa Ana River (County channel E01; OCFCD 2008; Property Condition Assessment 2011). The Santa Ana River is the major drainage channel flowing through the City and ultimately outlets into the Pacific Ocean. The Santa Ana River is located within 500 feet to the east of the project site and is not impaired (303(d) listed) in the vicinity of the project site (Reach 1; SWRCB 2006). Construction Impacts Tire potential impacts of construction activities on water quality focus primarily on sediments, turbidity, and pollutants associated with sediments. Construction - related activities that expose and move soils are primarily responsible for sediment releases. The project includes removal of existing concrete building pads and vegetation, site grading, soil preparation, and site trenching. These project activities could result in wind and rain erosion of the existing onsite soils and could increase the amount of suspended solids contained in storm flows due to erosion of exposed soils. Non - sediment potential contaminants that could enter water runoff from the construction site include paints, solvents, metals, oil, gasoline, petroleum products, concrete- related products, chemicals, and trash. All of these contaminants could contribute to the degradation of water quality. Because the project would disturb over 1 acre of land, the proposed project is subject to the General Construction Permit. The General Construction Permit, which was adopted by the SWRCB as Water Quality Order 99- 08 -DWQ on August 19, 1999, is required for soil disturbance activities that would be greater than 1 acre. Compliance with the General Construction Permit requires the development and implementation of a Storm Water Pollution Prevention Plan ( SWPPP), the elimination or reduction of non - stormwater discharge off site into storm drainage systems or other water bodies, and the implementation of BMPs. The SWPPP requires a description of the proposed project site, identification of sources of sediment and other pollutants that may affect the quality of storm water discharges, a list of BMPs to provide sediment and erosion control, waste handling measures, and non- stormwater management. The SWPPP would be required to meet or exceed measures required by the Construction General Permit. As a result, construction of the proposed project would result in less - than - significant impacts related to water quality standards. Impacts on Groundwater Quality. Historical high groundwater elevations below the project site are as shallow as 15 feet bgs. According to subsurface evaluations conducted for the 2011 geotechnical exploration study, depth -to- groundwater on the project site ranges between 32.0 and 41.6 feet. As described in Chapter 2, "Project Description," the proposed project would require minimal grading and a maximum excavation depth of 5 feet below the existing grade. Because The Academy Charter High School 12 20 June Initial Study /Mitigated Negative Declaration 3 -55 !CF June 2011 31 B -131