Shadehill Dam

Shadehill Dam is a dam (constructed 1951) on the Grand River in Perkins County in northwestern South Dakota in the United States, about south of Lemmon. The dam and its impoundment, Shadehill Reservoir, serve mainly for flood and silt control, wildlife conservation and recreation. Located directly below the confluence of the North and South Forks of the Grand River, the dam is operated by the U.S. Bureau of Reclamation, and is part of the Shadehill Unit of the Pick-Sloan Missouri Basin Program.
The dam is an embankment structure high and long, with an elevation of at the crest. A catchment area of lies above the dam site. At full pool, the reservoir has a capacity of , with a surface area of . Normal conservation water levels are much lower, at . Regular water discharges pass through an outlet works with a capacity of , while flood flows are released through two spillways: a morning glory inlet with a capacity of , and an emergency overflow channel that can pass up to .
Shadehill Dam was originally intended to serve irrigation purposes as well, but after determining that the water in the reservoir was too saline the Bureau of Reclamation dropped this phase from the project.