The Folsom Dam and Reservoir are located about 25 miles east of the city of Sacramento. Folsom Dam and Reservoir form a multipurpose water project constructed by the Corps of Engineers (Corps) and operated by the United States Bureau of Reclamation as part of the Central Valley Project (CVP). Folsom Dam and Reservoir is part of the Folsom Unit, which also consists of Folsom Powerplant, Nimbus Dam and Lake Natoma, Nimbus Powerplant and Nimbus Fish Hatchery.

Folsom Dam regulates runoff from about 1,875 square miles of drainage area. The reservoir has a normal full-pool storage capacity of 975,000 acre-feet with a minimum seasonally designated flood control storage space of 400,000 acre-feet. The reservoir provides flood protection for the Sacramento area; water supplies for irrigation, domestic, municipal, and industrial uses; and hydropower. It also provides extensive water-related recreational opportunities, water quality control in the Delta, and maintenance of flows stipulated to balance anadromous and resident fisheries, wildlife, and recreational considerations in and along the lower American River.

Lake Natoma serves as an afterbay to Folsom Reservoir. It allows dam operators to coordinate power generation and flows in the lower American River channel during normal reservoir operations. Lake Natoma has a surface area of 500 acres and its elevation fluctuates between four to seven feet daily.

The Folsom Unit was authorized in 1949 as part of the American River Division. Folsom Dam was originally authorized in the Flood Control Act of 1944 as a 355,000 ac/ft flood control unit. The reauthorization under the American River Division Authorization Act of 1949 changed the dam to a 1,000,000 ac/ft multipurpose facility with 162,000 kilowatt (k/w) powerplant. The act also authorized construction of Nimbus Dam and Lake Natoma.


US Bureau of Reclamation website –

US Army Corps of Engineers Website –