A part of the federal Central Valley Project, the Nimbus Dam and its after bay, Lake Natoma, are located 7 miles downstream of Folsom Dam on the American River.

The concrete gravity dam, just 87 feet high and 1,093 feet long, regulates American River flows. Lake Natoma has a capacity of 8,760 acre-feet. The dam was completed in 1955. Other associated facilities are the Nimbus Powerplant, the Nimbus Salmon and Steelhead Hatchery and the Folsom South Canal. 

The Nimbus fish hatchery, along with seven other hatcheries around the state such as the Coleman Fish Hatchery, have helped sustain the commercial ocean salmon catch. However, the hatcheries alone cannot replace the wild salmon stocks that biologists consider essential for the survival of the species.

Updated February 2026