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Redwood City Stormwater Roadmap <br />Current City Practices <br />September 2025 3-2 Schaaf & Wheeler <br />3.1.4 Levee Maintenance and Environmental Mitigation <br /> Cooperative Service Agreement (CSA) – Levee Predator Management: Under a five-year <br />agreement (2023 – 2028) with the USDA Animal and Plant Health Inspection Service <br />(APHIS), the City is managing predator species along the Redwood Shores levees to <br />protect federally listed species. The agreement satisfies mitigation conditions associated <br />with U.S. Army Corps of Engineers permits. Annual costs are budgeted up to $63,550, <br />with a total contract not to exceed $400,000. <br />3.2 Current Stormwater Maintenance Practices <br />Redwood City’s stormwater infrastructure is maintained by Public Works Services (PWS), with <br />support from regional partnerships and contracted services. Maintenance practices vary by asset <br />type and are aimed at ensuring operational reliability, reducing flood risk, and maintaining <br />compliance with regulatory requirements. <br />3.2.1 Pump Station Maintenance <br />PWS conducts preventive maintenance of stormwater pump stations at set intervals depending <br />on the equipment. Generator inspections and fuel tank checks are performed monthly, while <br />pumps, motors, and wet wells are maintained annually. Wet well cleaning includes sediment <br />removal to preserve pump efficiency. Trash racks are cleaned as needed, typically during the <br />winter storm season to reduce clogging risk. <br />3.2.2 Pipes, Channels, and Catch Basins <br />Maintenance activities include trash, debris, and sediment removal from catch basins and <br />concrete- lined channels, specific Cordilleras Creek culverts, and the Bayfront Canal. These <br />activities are generally performed annually and on an as-needed basis, guided by staff <br />observations and storm event response. Although the City maintains a comprehensive GIS <br />inventory of its storm drain system, there is currently no formal CCTV inspection program, unlike <br />for the sanitary sewer network. <br />3.2.3 Levee Maintenance <br />PWS performs routine levee inspections twice per year to identify and address maintenance <br />needs. Common activities include weed abatement, filling animal burrows, and regrading <br />localized trail depressions along levees in Redwood Shores. These efforts help maintain structural <br />integrity and access for inspections and emergency response. <br />3.2.4 Lagoon Maintenance <br />The City contracts annual summer maintenance for the Redwood Shores lagoon system. Tasks <br />include algae treatment and removal, widgeon grass management, and vegetation control. <br />Dewatering structures are periodically exercised (opened and closed) and cleaned to ensure <br />operability. Sediment accumulation near intake structures has been observed, and the City is <br />planning for future dredging activities to maintain lagoon function. <br />3.2.5 Green Infrastructure (GI) <br />Green infrastructure systems, such as bioretention basins, are maintained on a five-year <br />inspection cycle. Routine tasks include trash and sediment removal, vegetation trimming or <br />11.A. - Page 16 of 53 <br />447