Salt Springs Reservoir is a reservoir in the eastern portions of Amador County

Amador County, California

Amador County is a county located in the Sierra Nevada of the U.S. state of California. As of the 2010 census, the population was 38,091. The county seat is Jackson.Amador County bills itself as "The Heart of the Mother Lode" and lies within the Gold Country...

 and Calaveras County

Calaveras County, California

Calaveras County is a county located in the Gold Country of the U.S. state of California. Calaveras is the Spanish word for skulls; the county was reportedly named for the remains of Native Americans discovered by the Spanish explorer Captain Gabriel Moraga. As of the 2010 census, the county had a...

 of California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 in the Sierra Nevada about 30 miles (48.3 km) east-northeast of Jackson

Jackson, California

Jackson is the county seat of Amador County, California. The population was 4,651 at the 2010 census, up from 3,989 at the 2000 census...

. The reservoir is in the El Dorado National Forest at an elevation of 3900 feet (1,188.7 m). The 141900 acre.foot reservoir is formed by Salt Springs Dam on the North Fork of the Mokelumne River

Mokelumne River

The Mokelumne River is a river in Northern California. The Upper Mokelumne River originates in the Sierra Nevada mountain range and flows into Pardee Reservoir and then Camanche Reservoir in the Sierra foothills. The Lower Mokelumne River refers to the portion of the river below Camanche Dam...

. The concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

-faced rock-fill dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 is 332 feet (101.2 m) tall and was completed in 1931. It is owned by Pacific Gas and Electric and its sole purpose is hydroelectricity

Hydroelectricity

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

 production, though limited recreation is available. A short pipeline from the reservoir conveys water to the 44 MW Salt Springs Powerhouse. The water is returned to the river downstream.

The dam has a history of settlement problems caused by poor consolidation

Consolidation (geology)

Consolidation is a process by which soils decrease in volume. According to Karl Terzaghi "consolidation is any process which involves decrease in water content of a saturated soil without replacement of water by air." In general it is the process in which reduction in volume takes place by...

 of the rocks during construction. The concrete face has been cracked many times by the movement, causing leaks. The surface of the dam consists of cracks, craters and shotcrete

Shotcrete

Shotcrete is concrete conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique....

 overlays. It was decided to use a flexible geomembrane to cover the portions of the dam with the greatest leakage. The installation of the membrane was completed in 2005.