Anderson Lake County Park

Story

Anderson Lake, informally called Anderson Reservoir, is an artificial lake in Santa Clara County, California, United States, near Morgan Hill. A 4275acre county park surrounds the reservoir and provides limited fishing ("catch and release"), picnicking, and hiking activities. Although swimming is prohibited, boating, water-skiing and jet-skiing are permitted in the reservoir.HistoryThe reservoir was created in 1950 by the construction of the Anderson Dam across Coyote Creek in foothills of the Diablo Mountains east of Morgan Hill. The reservoir and dam were named after Leroy Anderson, a key founder and first president of the Santa Clara Valley Water District. It is the largest reservoir owned by the district.Anderson DamThe high earthen dam measures long by wide and sits along the Coyote Creek Fault on Coyote Road, east of Morgan Hill. The reservoir itself is situated parallel to the Calaveras Fault, which runs from Hollister to Milpitas. It holds over 90,000acre.ft of water when full, more than the other nine reservoirs in the county combined.Risk of dam failureIn January 2009, a preliminary routine seismic study suggested a small chance that a large-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 as far away as San Jose. In response, the Santa Clara Valley Water District (SCVWD) lowered the water level to 74 percent of 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 2km of the dam, potentially releasing a wall of water 35ft high into downtown Morgan Hill in 14 minutes, and 8ft deep into San Jose within three hours. In response SCVWD has lowered the water to 54% full, which is 60ft feet below the dam crest.