Reso 2021-113 Adopt 2021 CAP and Addendum to 2035 General Plan

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3. Climate Change Vulnerability Assessment increase to an average of 3.5 events per year by midcentury and an average of 4.25 events by the end of the century. Inland flooding can cause significant harm to buildings, people, and infrastructure. Floodwater can be deep enough to drown people and may move fast enough to carry away people or heavy objects (such as cars). Flooding can be caused by heavy rainfall, long periods of moderate rainfall, or clogged storm drains during periods of rainfall. In rare instances, a break in a water pipe or water tank can also cause flooding. Storm drainage systems throughout the City collect stormwater runoff and convey water to prevent localized flooding. However, these systems are typically designed based on winter storms recorded in the past and may not be designed to accommodate more intense storms. As seen ebeve previously in Figure 9, areas in San Leandro within the 100-year flood zono include land adjacent to San Leandro Creek, San Lorenzo Creek, and the Estudillo Canal; land along flood control channels in the vicinity of Bayfair Center and Bonaire Park; and coastal areas surrounding Oyster Bay Regional Shoreline, the San Leandro Shoreline, and Mission Bay. Several populations and assets face particularly high risks from flooding events. Persons experiencing homelessness, households in poverty, and linguistically isolated persons are severely vulnerable to flooding, as they may live in or near flood hazard areas, lack financial resources to protect their homes, or have difficulty receiving adequate evacuation notices due to language barriers. Persons with limited mobility and those without access to lifelines (persons without access to a car, transit, or communication systems) may have difficulty evacuating prior to a flooding event, and therefore are also highly vulnerable. An additional consequence of a property's designation within the 100-year flood zone is that flood insurance is required for federally -insured mortgage loans and may be required by other mortgage lenders. Additionally, 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. Transportation infrastructure, such as electric vehicle charging stations, evacuation routes, and major roads and highways, which are essential for public transit access, solid waste removal, and other services, can be inundated, blocked, and damaged by floodwaters. San Leandro's wastewater treatment plant is within the flood hazard area. Floodwaters can increase wet weather flow into the plant and cause permanent damage to the system and/or reduce its functionality. In cases of severe damage, the system can back up and flood neighborhoods with sewage. Most sewage lift stations are in low-lying areas San Leandro 2021 Climate Action Plan Page 53