New Melones Dam

New Melones Dam
Location	Sierra Nevada foothills Calaveras County, California Tuolumne County, California
Coordinates	37°56′57″N 120°31′27″W
Construction began	1966
Opening date	1979
Dam and spillways
Height	625 ft (191 m)
Length	1,560 ft (480 m)
Crest width	40 ft (12 m)
Impounds	Stanislaus River
Spillways	Uncontrolled overflow
Spillway capacity	112,600 cu ft/s (3,190 m3/s)
Reservoir
Creates	New Melones Lake
Capacity	2,400,000 acre·ft (3.0 km3)
Catchment area	900 sq mi (2,300 km2)
Surface area	12,500 acres (5,100 ha)
Power station
Commission date	1979
Hydraulic head	480 ft (150 m) (rated)
Turbines	2 x 150 MW Francis-type
Installed capacity	300 MW

New Melones Dam is an earth and rock filled dam across the Stanislaus River creating New Melones Lake. Situated between Calaveras and Tuolumne County, California in the Sierra Nevada foothills near Jamestown, the dam was completed in 1979 replacing the old Melones Dam.

Background

Old Melones Dam

The dam was constructed to replace the 183 ft (56 m) tall Melones Dam, an arch dam which was constructed in 1926 by the Oakdale and South San Joaquin Irrigation Districts. The new dam was authorized by the Flood Control Act of 1944 and reauthorized by the Flood Control Act of 1966 with an increase in height from a 355 ft (108 m) arch dam to 625 ft (191 m) tall embankment dam. Construction on the New Melones Dam began in July 1966 and the diversion tunnel was complete by 1973. On March 6, 1974, construction on the dam began and it was completed on October 28, 1978. By the end of 1978, the power plant was complete and it was commissioned in 1979. The filling of the reservoir began in 1983.

The United States Bureau of Reclamation operates the dam. New Melones Dam's primary purpose is to provide water for irrigation. It is a 625 ft (191 m) high earth and rock-filled structure creating a 2,400,000 acre·ft (3.0 km³) reservoir.

The dam has a hydroelectric plant with a capacity of 300 MW. It has three vertical Francis turbines and a head of 460 ft (140 m). The plant has a low capacity factor and operates as a peaking facility, which means that it operates mostly during times of peak electricity demand.

Controversy

The dam was one of the last built in California, as the environmental movement gained support, and as such was fiercely opposed by groups such as the Sierra Club, as well as many individuals who saw the canyon of the Stanislaus River as having value far beyond a reservoir. On May 20, 1979, Mark Dubois hiked into the dam site and chained himself to a boulder in the dam's floodpath, intending to block the U.S. Army Corps of Engineers from filling New Melones Lake. His protest action succeeded in temporarily securing a reprieve for the Class III whitewater rapids above the Parrott's Ferry Bridge. However, in 1983 due to a severe El Niño event and subsequent flood, the reservoir was finally allowed to reach full design capacity.

Several cave-dwelling species that were threatened by the construction were transplanted to an abandoned mine, among them Banksula melones, the Melones cave harvestman.

See also

• Central Valley Project

References

• Department of Water Resources (2009). "Station Meta Data: New Melones Dam (NML)". California Data Exchange Center. State of California. http://cdec.water.ca.gov/cgi-progs/profile?s=NML&type=dam. Retrieved 2009-09-17. 

External links

• New Melones Dam
• New Melones Power Plant
• Post-Audit of New Melones Dam, by Kimra Dawn McAfee (Master's Thesis, May 2000)
• U.S. Geological Survey Geographic Names Information System: (Tuolumne County)
• U.S. Geological Survey Geographic Names Information System: (Calaveras County)