East Bay Municipal Utility District (EBMUD) is a water utility providing water to 1.3 million people in the Oakland Bay Area. EBMUD's main source of water is the Mokelumne River watershed in the Sierra foothills, located about 90 miles northeast of the San Francisco East Bay Area. The aqueduct system that transports water to the service area consists of three large diameter steel pipelines of 65, 67, and 87, built in 1929, 1949, and 1963, respectively. These pipelines are a critical component of EBMUD's water system and the State of California's (State) overall water infrastructure. Approximately 15 miles of the aqueduct runs across the fragile Sacramento-San Joaquin Delta (Delta) area through 5 islands that are approximately 5 to 15 feet below mean sea level. This Delta crossing consists of approximately 4.5 miles of buried pipeline, 10 miles of elevated pipeline, and 3 major river crossings with about 0.5 miles of submerged pipeline. The Delta has approximately 1,100 miles of levees, many of significant height (up to 25 feet), which continuously impound sloughs and river waters and protect agriculture and urban areas within islands and tracts. The islands' floor in the central and western Delta is below sea level by up to 20 feet as a result of subsidence from farming of organic and peaty soils. There have been 166 levee failures leading to island inundations since 1900. The State is conducting studies on the Delta region as part of their Delta Risk Management Strategy (DRMS) project. As a part of the State's studies, all potential hazards from flooding and seismicity were identified and quantified and potential impacts and risks to the Delta levees were evaluated and quantified. Both flooding and seismicity fragility curves were developed for the Delta region on a Delta reach-by-reach basis. Geographic Information Systems were used to identify the hazard by levee reach.
