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3. Climate Change Vulnerability Assessment <br />San Leandro 2021 Climate Action Plan Page 39 <br />Although high temperatures in the City may not damage energy services, transmission lines going <br />through inland areas can be damaged or not function properly due to extreme heat. <br />Additional vulnerabilities include outdoor recreation, as people may be deterred from recreating <br />outdoors in high temperatures, and aquatic and wetland habitats, whose water quality may decline <br />as temperatures increase. <br />Flooding <br />As explained by the California Fourth Climate Change Assessment, California’s water system is <br />structured and operated to balance between water storage for dry months and flood protection <br />during rainy seasons. Although climate change is likely to lead to a drier climate overall, risks from <br />higher frequency, more intense rainfall events can generate more frequent and/or more severe <br />flooding that upsets this managed balance between storage and protection. <br />Climate change forecasts for the San Leandro region predict more intense rainfall events, more <br />frequent or extensive runoff, and more flooding. According to Cal-Adapt, historically, intense rain <br />events occurred an average of 2 times per year; they are projected to increase to an average of 3.5 <br />events per year by midcentury and an average of 4.25 events by the end of the century. <br />Inland flooding can cause significant harm to buildings, people, and infrastructure. Floodwater can <br />be deep enough to drown people and may move fast enough to carry away people or heavy objects <br />(such as cars). Flooding can be caused by heavy rainfall, long periods of moderate rainfall, or <br />clogged storm drains during periods of rainfall. In rare instances, a break in a water pipe or water <br />tank can also cause flooding. Storm drainage systems throughout the City collect stormwater runoff <br />and convey water to prevent localized flooding. However, these systems are typically designed <br />based on winter storms recorded in the past and may not be designed to accommodate more <br />intense storms. <br />As seen above in Figure 8, areas in San Leandro within the 100-year flood zone include land <br />adjacent to San Leandro Creek, San Lorenzo Creek, and the Estudillo Canal; land along flood <br />control channels in the vicinity of Bayfair Center and Bonaire Park; and coastal areas surrounding <br />Oyster Bay Regional Shoreline, the San Leandro Shoreline, and Mission Bay. <br />Several populations and assets face particularly high risks from flooding events. Persons <br />experiencing homelessness, households in poverty, and linguistically isolated persons are severely <br />vulnerable to flooding, as they may live in or near flood hazard areas, lack financial resources to <br />protect their homes, or have difficulty receiving adequate evacuation notices due to language <br />barriers. Persons with limited mobility and those without access to lifelines (persons without access <br />to a car, transit, or communication systems) may have difficulty evacuating prior to a flooding event, <br />and therefore are also highly vulnerable. <br />An additional consequence of a property’s designation within the 100-year flood zone is that flood <br />insurance is required for federally-insured mortgage loans and may be required by other mortgage <br />lenders. Additionally, the City’s Flood Plain Management Ordinance requires that new construction, <br />additions, and major home improvement projects be raised at least one foot above the base flood <br />83