Gavins Point Dam is a long embankment rolled-earth and chalk-fill dam which spans the Missouri River and impounds Lewis and Clark Lake. The dam joins Cedar County, Nebraska with Yankton County, South Dakota a distance of 811.1 river miles (1,305 km) upstream of St. Louis, Missouri, where the river joins the Mississippi River. The dam and hydroelectric power plant were constructed as the Gavins Point Project from 1952 to 1957 by the United States Army Corps of Engineers as part of the Pick-Sloan Plan. The dam is located approximately 4 miles (6.4 km) west or upstream of Yankton, South Dakota. History and background Gavins Point Dam was constructed as a part of the Pick–Sloan Missouri Basin Program, authorized by the Flood Control Act of 1944 by Congress. The dam is named after Gavins Point, a bluff along the northern bank of the Missouri River named for an early settler, now within the western end of Lewis & Clark Recreation Area, which was to be the original location of construction of the dam. The location was moved and construction began further downstream along Calumet Bluff because this location offered a shorter span distance and less fill material needed for dam construction, although the project kept the original name. The dam operations work in conjunction with the other Pick-Sloan Program Dams to assist with conservation, control, and use of water resources in the Missouri River Basin. The intended beneficial uses of these water resources include flood control, aids to navigation, irrigation, supplemental water supply, power generation, municipal and industrial water supplies, stream-pollution abatement, sediment control, preservation and enhancement of fish and wildlife, and creation of recreation opportunities. Gavins Point is the most downstream dam on the Missouri River, being 811.1 river miles upstream of St. Louis where the river meets the Mississippi River. The next dam upstream is Fort Randall Dam. 2011 Missouri River Flood During the 2011 Missouri River Flood, the dam released a record water flow of 160,200 cfs, topping the previous record of 70,000 cfs in 1997. During the 2011 flood, the debris damaged the dam and a significant portion of rocks were dislodged from its upstream side. The U.S. Army Corps of Engineers soon began repairs to the dam and its spillway gates. Pressure sensors were also installed in concrete portion of the dam. Hydroelectric power generation The dam has a hydroelectric power plant with three generators, each