[2] As part of the Central Valley Project (CVP), a federal water project that provides irrigation and municipal water to much of California's Central Valley, it was authorized in 1949 as a regulating reservoir for Folsom Dam, and a diversion pool for the Folsom South Canal.

The canal once provided cooling water for the SMUD nuclear power plant, Rancho Seco.

[6][circular reference] The United States Bureau of Reclamation released a final environmental assessment for the Nimbus Dam Radial Gates Maintenance Project in May 2015.

The report argues that over half the radial gates of Nimbus Dam need a new coating system, along with other repairs that fall outside of normal maintenance.

The project is expected to be completed by the end of 2019 and will focus on replacing the coating on the fourteen gates that have the original quoting.

The rapid water exchange from Nimbus Dam sharply decreases the production of plankton, which inhibits trout growth.

[8] 125 miles of habitat for Chinook and steelhead salmon were accessible in the American River Watershed before the construction of Nimbus Dam.

In the American River Basin, approximately 40% of the annual runoff is a result of melting snow in the Sierra Nevada Mountains.

As a result, low natural flow rates in the American River system in the later summer months.

Due to the contamination of the groundwater because of environmental degradation in the lower American River, the County of Sacramento created a Water Forum in 1993.