Folsom Dam and Reservoir, part of the Central Valley Project, were built by the Corps beginning in October 1948 and completed in May 1956, after which the dam was transferred to the Bureau of Reclamation for operation. The concrete gravity dam is 340 feet high and 1,400 feet long, with left and right earthfill wing dams, and the larger Folsom Facility also includes Mormon Island Auxiliary Dam and eight earthfill dikes. Water was first stored in February 1955, and the reservoir has a storage capacity of 977,000 acre-feet at an elevation of 466 feet. The facility supplies water for municipal and industrial use and agriculture, generates 10 percent of local hydropower needs, maintains flows and water temperatures for fish and wildlife, provides flows for Sacramento-San Joaquin Bay-Delta water quality, and offers recreation for 2 million visitors annually. Since 1955, the Bureau of Reclamation and the U.S. Army Corps of Engineers have worked together to maintain and operate the facility safely, providing downstream protection as well as power and a reliable water supply. Their joint efforts have addressed dam safety by reducing hydrologic, seismic, and static risks and have pursued flood-damage reduction in the Sacramento area through coordinated facility modifications, including the auxiliary spillway known as the Joint Federal Project, in partnership with the Central Valley Flood Protection Board and the Sacramento Area Flood Control Agency.