SFPUC 2001 Alameda Watershed Management Plan

III. ENVIRONMENTAL SETTING AND IMPACTSD. HYDROLOGY AND WATER QUALITYapproval that require implementation of mitigation measures to avoid or reduce impacts tohydrology and water quality. These measures include construction of a continuous slurry wallaround the mining pit; drainage, erosion, and sediment controls; testing of overburden forcontaminants and isolation of any soil found to be a potential source of nitrates or mineralpollutants; maintaining existing runoff patterns or constructing a sediment basin and an energydissipater prior to discharge to Alameda Creek; compliance with regulations of the RegionalWater Quality Control Board; development and approval of a spill containment and cleanupplan; and groundwater quality monitoring according to the requirements of the SFPUC (AlamedaCounty Planning Department, 1994).2.0 IMPACTS2.1 SIGNIFICANCE CRITERIAThe City has not formally adopted significance standards for hydrology and water qualityimpacts, but it generally considers that implementation of the Alameda Watershed ManagementPlan would have a significant effect on hydrology and water quality if it were to:! substantially change absorption rates, drainage patterns, or the rate and amount of surfacewater runoff;! substantially degrade water quality;! contaminate a public water supply;! substantially degrade or deplete groundwater resources or interfere with groundwaterrecharge; or! cause substantial flooding, erosion, or siltation.Criteria for evaluating surface and ground water quality in the San Francisco Bay Area are basedon beneficial uses and water quality objectives established by the Regional Water QualityControl Board, San Francisco Bay Region, as authorized under the Porter-Cologne Water QualityControl Act. Both beneficial uses and water quality objectives applicable to waterbodies withinthe area affected by the Management Plan are described in The Water Quality Control Plan forthe San Francisco Bay Basin, also referred to as the Basin Plan (California RWQCB, 1995).Criteria for evaluating impacts to drinking water quality are based on California Drinking WaterStandards, as established by the California Safe Drinking Water Act. Criteria for evaluatingflooding hazards are based on effects to on-site and downstream 100-year flood zones, asestablished by the Federal Emergency Management Agency.2.2 PROGRAM-LEVEL IMPACTSThe primary goal of the Management Plan is to maintain and improve the quality of sourcedrinking water in order to protect public health and safety. Water Quality Policies WQ1 toWQ31 are specifically designed to address the management of natural resources, WatershedNOP 96.223E: Alameda Watershed Management Plan III.D-8 ESA / 930385January 2001