Calaveras Reservoir

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Calaveras Reservoir is a lake located primarily in Santa Clara County, California with a small portion and its dam in Alameda County, California. The reservoir has a capacity of 100,000 acre-feet (123,000,000 m³).

Calaveras Reservoir and Dam in May 2006

Calaveras Dam, which creates the reservoir, used to be the largest earth fill dam in the world. It is 210 feet (64 m) tall and was completed in 1925. The city and county of San Francisco owns the dam and reservoir.

Poverty Ridge and Oak Ridge lie to the east of Calaveras Reservoir, Milpitas and Monument Peak lie to the west, Sunol lies to the far north, and Calaveras Creek and Los Buellis Hills lie to the south.

Calaveras Reservoir in Spring 2006

Calaveras Reservoir is fed mainly by Arroyo Hondo and Calaveras Creek. Lying in the Calaveras Valley, the region is a geologically active area with the Calaveras Fault running below it. Roads adjacent to the reservoir include Calaveras Road and Marsh Road, the latter which gained significant public attention due to a murder which occurred there in the early 1980s.

Some livestock along Calaveras Road in May 2006

The Calaveras Valley is rich and diverse in wildlife. Some of the most common animals include deer, coyotes, squirrels, turkey vultures, red-winged blackbirds, yellow-billed magpies, red-tailed hawks, brewer's blackbirds, purple martins, barn swallows, bullock's orioles, and warblers.

In the 1800s, the Calaveras Valley which the reservoir now fills was primarily an agricultural region known for its production of hay, strawberries, and tomatoes. Because of San Francisco's increasing demand for drinking water at the turn of the 20th century, the farmers in the region were forced to sell their land to the Spring Valley Water Company, which in turn sold it to the San Francisco Water Company. Although the first dam that was constructed collapsed due to engineering flaws, another dam was soon built. The flooding of the Calaveras Valley rapidly changed its sensitive hydrology and natural environment.

Today, the San Francisco Water Department owns most of the land surrounding the reservoir, which is usually leased to livestock companies for cattle ranching. Most of the land is closed to the public because of concerns over drinking water safety and quality. Recently, legislators passed an act which will open the reservoir to boaters, fishermen, and hikers under limited terms.

In 2005, the San Francisco Public Utilities Commission planned for a great expansion of the reservoir, which will flood another 3,500 acres (14 km²) of wilderness land. The plan is currently only a proposal and has not yet gone into effect, but the Calaveras region would be drastically altered hydrologically and ecologically if the proposal were put into effect. [1]