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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 <br />E N V I R O N M E N T A L H A Z A R D S <br />7-13 <br /> <br /> <br /> <br />Other Flood Hazards <br />Dam Failure. Dam failure refers to the uncontrolled release of <br />impounded water stored behind a dam. It can be caused by heavy rainfall, <br />earthquakes, landslides, improper operation or maintenance, poor <br />construction or maintenance, vandalism, and other natural or human <br />actions. The California Office of Emergency Services (CalOES) requires <br />the preparation of Emergency Action Plans by dam operators identifying <br />warning, evacuation, and post-flood actions in the event of failure. <br />CalOES prepares dam inundation maps for major dams around the state. <br />Their maps indicate that San Leandro would be directly impacted by <br />failure of either of the East Bay Municipal Water District (EBMUD) dams <br />on San Leandro Creek. The Upper San Leandro Reservoir Dam was built <br />in 1977 and the Lake Chabot Dam was built in 1892. Both dams are <br />inspected annually to ensure they are safe and performing as intended. <br />While failure of these dams is extremely unlikely, fast-moving water could <br />cause substantial damage in the northern part of San Leandro and would <br />flood most of the city. <br /> <br />Tsunamis. Tsunamis are oceanic waves that are generated by <br />earthquakes, volcanic eruptions, or underwater landslides. Most tsunamis <br />result in strong and fast tides, rather than giant breaking waves; <br />casualties are often the result of currents and floating debris. <br />Although over 50 tsunamis have been observed in the Bay Area since <br />1850, local damage has been very limited. The risk is much lower in San <br />Leandro than it is in coastal cities because the Bay is an enclosed body of <br />water. There is a slight potential for flooding in low lying areas along the <br />immediate shoreline. Portions of the shoreline area with elevations less <br />than 12 feet above sea level are located within a designated tsunami <br />inundation evacuation zone and could face an evacuation order in the <br />event of a very large off-shore earthquake. <br />Resolution No. 2025-151 Exhibit A 13 of 84