The tunnels were cleaned and readied for placement of the penstock pipes by October 9. Installation of the three, 15.5-foot diameter penstock tubes that supply water to the turbines at the Folsom Powerplant began October 5, 1953. It reregulates the releases for power made through the Folsom Powerplant. . Nimbus Dam is a concrete gravity dam 1,093 feet long and 87 feet high. The total volume of material used in the dam is 121,100 cubic yards.
Reclamation operates the dam.
Nimbus Dam and Powerplant was completed and accepted by the Government in July 1955. Nimbus Dam forms Lake Natoma, with a capacity of 8,760 acre-feet and a surface area of 540 acres. Nimbus Powerplant Nimbus Powerplant, constructed and operated by Reclamation, is located on the right abutment of Nimbus Dam, on the north side of the river. Each of its two generators has a capacity of 7,763 kilowatts, with a combined output of 3,500 kilowatts. It started operating in 1955.