Anderson Reservoir is a man-made lake along Coyote Creek in Santa Clara County, California, U.S., near Morgan Hill. Anderson Dam was built in 1950 to provide drinking water for Santa Clara county; the lake has also become a source of recreation to nearby residents. Anderson Reservoir is the largest man-made lake in Santa Clara County. It is sometimes called Anderson Lake.The 3,144-acre Anderson Lake County Park surrounds the reservoir, and provides fishing ("catch and release" due to mercury contamination), picnicking, and hiking activities. Boating, water-skiing and jet-skiing are permitted in the reservoir.Risk of dam failureThe 235-foot high earthen Leroy Anderson Dam sits on Cochrane Road, east of Morgan Hill, and along the Calaveras Fault, which runs from Hollister to Milpitas. It holds of water when full: more than the other nine reservoirs in the county combined.In January, 2009, a preliminary routine seismic study suggested a small chance that a high-magnitude earthquake (6.6 with the dam at the epicenter, or 7.2 up to a mile away) could result in flooding in Morgan Hill and up to as far away as San Jose. In response, the Santa Clara Valley Water District (SCVWD) lowered the water level to 74% capacity and announced further analysis of the situation, which could possibly result in retrofitting the dam if necessary. Updated findings in October, 2010 indicated that the dam could fail if a magnitude 7.25 earthquake occurred within 2 kilometers of the dam, potentially releasing a wall of water 35 feet high into downtown Morgan Hill in 14 minutes, and 8 feet deep into San Jose within three hours. In response SCVWD has lowered the water to 54% full, which is 60 feet below the dam crest.
