5A Public Hearing 2019 0204 - Laserfiche WebLink

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3.0 ENVIRONMENTAL CHECKLIST City of San Leandro 1388 Bancroft Avenue Project November 2018 Initial Study/Mitigated Negative Declaration 3.0-49 As part of Section 402 of the Clean Water Act, the EPA has established regulations under the National Pollutant Discharge Elimination System program to control both construction and operation (occupancy) stormwater discharges. In the Bay Area, the San Francisco Regional Water Quality Control Board (RWQCB) administers the NPDES permitting program and is responsible for developing permitting requirements. The project would be subject to the San Francisco Bay Region Municipal Regional Stormwater National Pollutant Discharge Elimination System Permit (MRP) – NPDES Permit Order No. R2-2015-0049, and the provisions set forth in Section C.3, New Development and Redevelopment. Under this program, the project would be required to eliminate or reduce non-stormwater discharges, develop and implement a construction SWPPP, and perform inspections of the stormwater pollution prevention measures and control practices to ensure conformance with the site’s SWPPP. Because the project would disturb at least 1 acre of land, the project must provide stormwater treatment and would be required to obtain coverage under the General Permit for Discharges of Storm Water Associated with Construction Activity (Construction General Permit Order 2009-0009-DWQ or 2009-0009-DWQ General Permit). Further, in accordance with San Leandro Municipal Code Section 7-12-230, the project would be required to prepare and implement an erosion and sedimentation control plan and a drainage plan which includes BMPs to minimize erosion and sediment runoff. The project would implement construction BMPs, including only performing earthmoving activities during dry weather, using sediment controls or filtration to remove sediment when dewatering, protecting storm drain inlets from sediment, diverting on-site runoff around the site, and using sediment barriers. With these measures, the project’s construction impacts on water quality would be less than significant. Operational Impacts Currently, the site is developed with 49,506 square feet of impervious area, including 38,462 square feet of paved areas and 11,044 square feet of roof area. The project would result in a 6,214-square-foot decrease in impervious surfaces. As a result, the amount of runoff generated from the project site would decrease. To help ensure that drainage from new development meets discharge control standards, a Stormwater Control Plan was prepared for the project and reviewed by the City. The Stormwater Control Plan calculated the change in impervious surfaces and defined needed drainage improvements per City standards, the state Stormwater Management and Urban Runoff Control Program, and the Alameda County Clean Water Program. All site runoff would be directed from on-site drainage pipes to the City’s existing municipal storm drainage system and ultimately to the countywide drainage system. The project’s drainage improvements would be constructed in compliance with the City’s standard conditions for new development. Therefore, with these measures, the project would not generate stormwater discharges that would violate water quality standards or waste discharge requirements. With these standard development requirements and measures in place, the impact would be less than significant. b) Less Than Significant Impact. The proposed project would not 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. Domestic use of groundwater wells in San Leandro is currently not permitted due to contamination by volatile organic compounds, gasoline, and heavy metals (San Leandro 2016b). The project would decrease the overall level of impervious surfaces on the project site, increasing the amount of groundwater recharge. Furthermore, the project would incorporate stormwater BMPs, including detention basins to retain stormwater on-site,