Nimbus Dam, on the American River 7 miles below Folsom Dam formed Lake Natoma to reregulate the releases for power made through Folsom Powerplant. The Nimbus Fish Hatchery was built on the left bank below the dam to compensate for the spawning areas of salmon and steelhead that were inundated by construction of Nimbus Dam. Nimbus Dam is a feature of the Central Valley Project - American River Division - Folsom and Sly Park Units. Open year-round for fish rearing and educational actvities. Fish spawning demonstrations provided during the salmon and steelhead runs. Call 916-358-2884 for more information.