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

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3. Climate Change Vulnerability Assessment Landslides and mudslides can move fast enough to damage or destroy homes or other structures in their path, block roadways (including evacuation routes), and injure or kill people caught in them. The most vulnerable populations are those that may be unable to evacuate due to limited mobility, lack of access to a vehicle, or language barriers that may prevent awareness of emergency notifications. Those living on single -access roadways in the hilly portion of the City or those living in less resilient housing may lose access to their homes if roadways or the structures are damaged or destroyed by a landslide. Infrastructure, such as natural gas pipelines and water or wastewater infrastructure, can break or malfunction if the soil supporting them fails. This can lead to disruptions in energy delivery and water or wastewater services. Sea -Level Rise As global temperatures rise, glaciers and other land ice near the north and south poles melt. The water flows into the ocean, increasing sea levels across the globe. Higher temperatures also cause water to expand in oceans, causing further rising of sea levels. SLR is a gradual process, taking place over years or decades. In California, guidance suggests that sea levels will increase by 6 to 10 inches in most places by 2030, 13 to 23 inches by 2050, and 41 to 83 inches by 2100.44 However, it is possible that sea levels could rise faster than these projections.45 Along San Leandro's bay shoreline, sea levels are projected to rise approximately 24 inches by 2050 and as much as 84 inches by 210046 Rising sea levels can increase the frequency and severity of bay shoreline flooding. Since SLR raises ocean levels, shoreline floods, such as king tides and storm surges, can reach further onto land. For example, a storm that has a 1 in 10 chance of occurring in a given year (known as a 10-year storm), can create a temporary increase in sea levels of approximately 28 to 30 inches. This means that if sea levels rise by 24 inches during normal conditions, a 10-year storm event would create a temporary SLR of around 52 inches.47 Bayshore flooding zones in 2050 and 2100 are shown ebeve in Figure 9. Higher sea levells can also give a "boost" to smaller floods that would not have been large enough to flood dry land during normal conditions, making shoreline flooding more frequent. Eventually, sea level may increase enough to permanently flood low-lying areas in the eastern portion of San Leandro along the bayshore. Homes within the Mulford Gardens, Marina Faire, and Heron Bay neighborhoods are within the SLR inundation area. 48 SLR can increase residential flooding in these neighborhoods, causing mold and mildew to grow. Eventually, homes in these neighborhoods may become uninhabitable. Homes and structures built above sea level can still be harmed if the higher levels of water erode the rock or soil supporting the structures, potentially making them unsafe or at risk of collapse. San Leandro 2021 Climate Action Plan Page 55