The U.S. Bureau of Reclamation (Reclamation) is proposing to provide funding and authorization to Sites Authority for the proposed construction and operation of an offstream surface water reservoir to provide direct and real benefits to instream flows, the Sacramento–San Joaquin Delta ecosystem, and water supply reliability. Reclamation is providing funding through the 2021 Water Infrastructure Improvements for the Nation Act funds. The project would use existing infrastructure to divert unregulated and unappropriated flow from the Sacramento River at Red Bluff and Hamilton City and convey the water to a new offstream reservoir west of the community of Maxwell, California. New and existing facilities would move water into and out of the reservoir, with ultimate release back to the Sacramento River system via existing canals and a new pipeline located near Dunnigan, California. Water released from Sites Reservoir would be used to benefit local, State, and federal water use needs, including municipal, industrial, and agricultural public water agencies, anadromous fish species in the Sacramento River watershed, wildlife refuges and habitats, and the Yolo Bypass to help supply food for delta smelt. Construction of Sites Reservoir would necessitate construction of a bridge or bypass road to connect Maxwell with the community of Lodoga. Additional components would include the development of new recreation facilities at the reservoir. When completed, the project will convey water from the Sacramento River through existing conveyance facilities, both federally and privately owned, to new and existing regulating reservoirs and then transport to the new Sites Reservoir for storage. Existing and new facilities will convey water from the Sites Reservoir to the Colusa Basin Drain via the Tehama-Colusa Canal for release and flows will enter the Yolo Bypass or Sacramento River. The undertaking includes construction of the new facilities, connection of such facilities to existing facilities, and operation of the project.