Reso 2025-151 Environmental Hazards Element General Plan

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S A N L E A N D R O G E N E R A L P L A N E N V I R O N M E N T A L H A Z A R D S 7-12 The principal consequence of a property’s location within the 100-year flood zone is that flood insurance is required for federally insured mortgage loans. Insurance also may be required by other mortgage lenders. Moreover, the City’s Flood Plain Management Ordinance requires that new construction, additions, and major home improvement projects be raised at least one foot above the base flood elevation—this can be a significant expense for homeowners making alterations to existing structures. FEMA regulations also require that any development in the flood plain must be preceded by a hydrologic and hydraulic analysis and must demonstrate that the development does not cause any increase in flood hazards elsewhere. FEMA revised its coastal flood maps for Bay Area counties and finalized revised Flood Insurance Rate Maps (FIRMs) effective December 2018. The Alameda County Public Works Agency and the City of San Leandro are working together on actions that will remove approximately 1,000 properties in western San Leandro from the 100- year flood plain designation shown on these maps. This will require the construction of sea walls in locations such as the western edge of Mission Bay Mobile Home Park, and the raising of bank heights along the Estudillo Canal below Wicks Boulevard. The City and Flood Control District are in the process of evaluating and improving other levees so they meet FEMA certification standards. This could remove additional areas from the 100-year floodplain. Other planned flood control projects in the San Leandro area include rehabilitation of the Estudillo Canal tide gates, and hazardous tree removal along San Leandro Creek. FEMA is also studying the effects of sea level rise on Bay Area shorelines, creeks, and levees to determine what changes may be needed to provide adequate flood protection. ACFCWCD is also studying options to provide greater flood protection to properties in the San Lorenzo Creek watershed, including increasing the capacity of Don Castro Reservoir, constructing flood walls, and removing bottlenecks along the San Lorenzo Creek channel. Increased precipitation intensity associated with climate change may increase flood risk in the City. Areas located in FEMA-designated flood zones, including along creeks and streams in San Leandro, are at greatest risk for larger and more frequent flood events. Resolution No. 2025-151 Exhibit A 12 of 84