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2 Environments 7.B. - Page 85 <br /> water to the existing sanitary sewer system within in the project area. Thus,dewatering would not <br /> have any water quality impacts to surface or groundwaters in the area. <br /> The stormwater discharges would comply with the SMCWPPP requirements and the shared City of <br /> Redwood City and San Mateo County NPDES Permit No. CAS612008. The discharges would be <br /> subject to existing monitoring and inspection requirements. <br /> The stormwater that collects in the new joint-use path would discharge through two new 18-inch <br /> pipes to Redwood Creek. <br /> The following mitigation measures would reduce the potential impacts of the project to water quality. <br /> Mitigation Measure HYD 1: Implementation of BMPs <br /> A Storm Water Pollution Prevention Plan (SWPPP) shall be prepared for the project. The <br /> BMPs contained in the SWPPP shall be implemented, and the NPDES Permit Compliance <br /> Checklist (see Appendix I) to control and prevent the potential discharge of non-stormwater <br /> discharges and pollutants to Redwood Creek during construction shall be completed. The <br /> Contractor shall utilize measures such as sediment barriers, silt fences, straw wattles, <br /> biodegradable fiber rolls, or hydraulic mulches to trap sediment in stormwater runoff away <br /> during construction to prevent the discharge of pollutants to Redwood Creek. The <br /> Contractor shall revegetate the disturbed areas of landscaped vegetation along the creek <br /> banks with a hydroseed native plant mix for slope stabilization. The Contractor shall <br /> implement rock slope protection (RSP) on the creek bank below the proposed 18-inch <br /> drainage pipes' discharge points to prevent erosion along the creek bank. <br /> With the incorporation of these measures,the impacts to water quality would be reduced to less than <br /> significant levels. (Less than Significant Impact with Mitigation Incorporation) <br /> b)Substantially deplete groundwater supplies or interfere substantially with groundwater <br /> recharge such that there would be a net deficit in aquifer volume or a lowering of the local <br /> groundwater table level(e.g., the production rate of pre-existing nearby wells would drop to a <br /> level which would not support existing land uses or planned uses for which permits have <br /> been granted)? <br /> Excavation for the 26-foot deep wet well at the replacement pump station,trenching for the <br /> pipelines,and excavation for the joint-use path would likely encounter groundwater at levels below 2- <br /> 4 feet and need dewatering. The City does not use groundwater for water supply wells. The required <br /> dewatering would affect groundwater levels in the immediate vicinity of the project, but would not <br /> have a substantial effect on groundwater supplies or interfere with groundwater recharge activities. <br /> (Less than Significant Impact) <br /> 2-45 US 101 Pedestrian Undercrossing and Bair <br /> Island Road Storm Drain Pump Station Project <br />