Auburn Dam

Auburn Dam
A concept drawing of the Auburn Dam, from the U.S. Army Corps of Engineers
Location	Near Auburn, California
Coordinates	38°52′55″N 121°03′43″W / 38.88194°N 121.06194°W / 38.88194; -121.06194Coordinates: 38°52′55″N 121°03′43″W / 38.88194°N 121.06194°W / 38.88194; -121.06194
Construction began	19 October 1969
Opening date	never completed
Construction cost	$431 million
Owner(s)	U.S. Bureau of Reclamation
Dam and spillways
Type of dam	Concrete gravity-arch
Impounds	North Fork American River
Height	680 feet (210 m)
Length	4,100 feet (1,200 m)
Reservoir
Creates	Auburn Reservoir
Total capacity	2,300,000 acre feet (2,800,000 dam3)
Surface area	10,000 acres (4,000 ha)
Power station
Installed capacity	200–750 MW

Auburn Dam was a proposed concrete arch dam on the North Fork of the American River east of the town of Auburn, California in the United States, on the border of Placer and El Dorado Counties. Slated to be completed in the 1970s by the U.S. Bureau of Reclamation, it would have been the tallest concrete dam in California and one of the tallest in the United States, at a height of 680 feet (210 m) and storing 2,300,000 acre feet (2.8 km³) of water. Straddling a gorge downstream of the confluence of the North and Middle Forks of the American River and upstream of Folsom Lake, it would have regulated water flow and provided flood control in the American River basin as part of Reclamation's immense Central Valley Project.

The dam was first proposed in the 1950s; construction work commenced in 1968, involving the diversion of the North Fork American River through a tunnel and the construction of a massive earthen cofferdam. Following a nearby earthquake and the discovery of a seismic fault that underlay the dam site, work on the project was halted for fears that the dam's design would not allow it to survive a major quake on the same fault zone. Although the dam was redesigned and a new proposal submitted by 1980, spiraling costs and limited economic justification put an end to the project until severe flooding in 1986 briefly renewed interest in Auburn's flood control potential. The California State Water Resources Control Board denied water rights for the dam project in 2008 due to lack of construction progress.

Although new proposals surfaced from time to time after the 1980s, the dam was never built for a number of reasons, including limited water storage capacity, geologic hazards, and potential harm to recreation and the local environment. Much of the original groundwork at the Auburn Dam site still exists, and up to 2007, the North Fork American River still flowed through the diversion tunnel that had been constructed in preparation for the dam. Reclamation and Placer County Water Agency completed a pump station project that year which blocked the tunnel, returned the river to its original channel, and diverted water through another tunnel under Auburn to meet local needs. However, some groups continue to support construction of the dam, which they state would provide important water regulation and flood protection.