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activities to the north and south of the Site may influence the local groundwater flow direction at times of dewatering. The lower water-bearing unit of the Tulare Formation lies beneath the confining Corcoran Clay and provides better water quality than the upper water-bearing unit. The bottom of the fresh water-bearing unit is underlain by sedimentary rocks that are of marine origin and are not fresh water bearing. Recharge of the lower water-bearing unit is mostly from rainfall and snowmelt runoff originating from the Sierra Nevada Mountains. Some recharge occurs from precipitation in the Diablo Range and Coastal Ranges; however, most of this runoff drains to the west. The nearest surface water features to the project site are Corral Hollow Creek to the north, an intermittent natural drainage course; the Delta-Mendota Canal, an irrigation canal; and the California Aqueduct. The topographic nature of the Site precludes it as a potential source of runoff to any of these water features. The Site is a former gravel mine and is in essence a closed basin with no outfall. All rainwater that falls onto the Site infiltrates into the soil substrate and serves as local groundwater recharge. Analysis of Potential Impacts: Describe to what extent project activities would: a. Violate any water quality standards or waste discharge requirements. Less Than Significant Impact. Implementation of the proposed remedial action plan is not anticipated to cause any short-term or long-term water quality or hydrology impacts (SW RCB 2003). There will be no runoff discharged from the Site during or following project implementation because the Site is contained within a closed basin. However, because the proposed project activities include excavation of at least one acre of land and removal of materials off-site, the project activities are subject to coverage under the National Pollutant Discharge Elimination System (NPDES)General Permit for Storm Water Discharges Associated with Construction Activity. The proposed project is designed to comply with the General Permit as described previously within the project description section. The General Permit requires all dischargers where construction activity disturbs one acre or more to: 1. Develop and implement a Storm Water Pollution Prevention Plan (SW PPP)which specifies Best Management Practices (BMPs), to be approved by the San Joaquin County Health Department, that will prevent construction pollutants from contacting storm water and with the intent of keeping all products of erosion from moving off site into receiving waters. 2. Eliminate or reduce non-stormwater discharges to storm sewer systems and other waters of the nation. 3. Perform inspections of all BMPs. b. Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficient in aquifer volume or a lowering of the local groundwater table level (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted). Less Than Significant Impact. Overall recharge rates will not be affected by the proposed project because the project does not involve any level of site development. The project will result in a beneficial long-term influence to groundwater resources in the area due to the removal of contaminants that have the potential to affect groundwater resources. 33