21 ATTACHMENT 3 - Laserfiche WebLink

80 inactive, faults intersect active or potentially active faults. Any movement of the master fault could trigger adjustments on minor cross faults or adjacent subparallel faults. City of Pleasanton: See above. Flood. The area in which LAVWMA, DSRSD, Livermore and Pleasanton provide service, like many regions in California, may be subject to flood damage. The following information about flood risk in that area is derived from the general plan documents for LAVWMA, DSRSD, Livermore, Pleasanton and, where indicated, the cities of Dublin and San Ramon. Livermore. According to the Federal Emergency Management Agency (“FEMA”), the majority of Livermore is subject to minimal flooding, although there are 100-year flood zones in some portions of Livermore. Most flooding within Livermore is caused by heavy rainfall and subsequent runoff volumes that cannot be adequately conveyed by the existing storm drainage system combined with surface water bodies. Flooding could also result from the catastrophic failure of nearby Del Valle Dam and Patterson Reservoir, which would result in the release of a large volume of water in a relatively short period of time. Livermore is not subject to inundation by coastal hazards. Pleasanton. According to FEMA information, approximately 1,900 acres in Pleasanton are in the 100-year FEMA flood plain and approximately 3,425 acres are in the 500-year flood plain. In addition, approximately 6,000 acres in Pleasanton are located within the dam failure inundation hazard area for Lake Del Valle Dam. The 235-foot Del Valle Dam impounds a reservoir with a total capacity of 77,100 acre-feet. To provide a flood-protection reserve, it normally stores from 25,000 to 40,000 acre-feet. This dam is under the jurisdiction of the California Department of Water Resources (“DWR”), Division of the Safety of Dams. Existing dams under DWR jurisdiction are periodically inspected to ensure adequate maintenance and to direct the owner to correct any deficiencies found. Dam failure and flooding could potentially cause DSRSD’s sewage treatment plant to overflow, resulting in raw sewage flowing down Alameda Creek leading to short-term negative impacts. DSRSD. City of Dublin: According to the Seismic Safety and Safety Element of the City of Dublin’s General Plan, flooding has not been a major problem in the City of Dublin and, as of January 1992, there were no major flood improvement projects needed or planned for the City of Dublin. City of San Ramon: According to the Safety Element of the City of San Ramon’s General Plan 2020, based on information from FEMA, a majority of Contra Costa County’s creeks and shoreline lie within the 100-year floodplain. Drainage facilities in Contra Costa County are provided by the cities, the County of Contra Costa, and the Contra Costa County Flood Control and Water Conservation District. City of Pleasanton: See above. Fire Hazard. The area in which LAVWMA, DSRSD, Livermore and Pleasanton provide service, like many regions in California where development occurs outside an urban core, is an