Nimbus Dam, 7 miles downstream of Folsom Dam on the American River, regulates releases made through Folsom Dam. Nimbus Dam forms Lake Natoma, with a surface area of 540 acres and a capacity of 8,760 acre-feet. Nimbus Dam is a concrete gravity dam 1,093 feet long and 87 feet high. Eighteen radial gates, each 40-feet by 24-feet, control the flows.
A loud horn and flashing siren, along with posted signage, notifies the public to stay clear when releases will soon be increasing.
Nimbus Powerplant is located on the right abutment of the dam, on the river’s north side. Its two generators have a capacity of 7,763 kilowatts each. Water is supplied to the two 9,400 horsepower turbines that drive the generators through six 46.5-foot-long penstocks. Nimbus Dam and Powerplant began operating in 1955.
General
Project
CVP-Folsom
Longitude
-121.2233
Watercourse
American River
Reservoir
Lake Natoma
Original Construction
1952-1955
Latitude
38.6367
National ID Number
CA10174
Base Width
135 ft
Dimensions
Structural Height
87 ft
Crest Length
1093 ft
Crest Width
28 ft
Volume of Dam Construction Materials
121000 cu yd
Crest Elevation
132.0 ft
Hydraulic Height (Normal Operating Depth at Dam)
46 ft
Hydraulics & Hydrology
Spillway Capacity at Elevation
300000 cfs at 126.5
Drainage Area
1898 sq mi
Total Water Storage at Elevation
8760 acre-ft at 125
Net Generation
67,752,000 kWh
Contact
Owner
Title: Area Office Manager Organization: Central California Area Office Address: 7794 Folsom Dam Road City: Folsom, CA 95630 Phone: 916-537-7100
Operator
Title: Area Office Manager Organization: Central California Area Office Address: 7794 Folsom Dam Road City: Folsom, CA 95630 Phone: 916-537-7100
More Information about the U.S. Bureau of Reclamation