| Shadehill Dam | |
| Location Map: | South Dakota |
| Coordinates: | 45.7525°N -102.2023°W |
| Country: | United States |
| Location: | Perkins County in northwestern South Dakota |
| Status: | O |
| Opening: | 1951 |
| Owner: | United States Bureau of Reclamation |
| Dam Type: | Embankment |
| Dam Height: | 1450NaN0 |
| Dam Length: | 128430NaN0 |
| Dam Elevation Crest: | 23180NaN0 above msl |
| Dam Crosses: | Grand River |
| Res Name: | Shadehill Reservoir |
| Res Capacity Total: | 468585acre feet[1] (Maximum Pool) |
| Res Capacity Active: | 81443acre feet (Normal Pool) |
| Res Catchment: | 3,120 square miles (8,100 km2) |
| Res Surface: | 121500NaN0 |
| Website: | Shadehill Dam - USBR |
Shadehill Dam is a dam (constructed 1951) on the Grand River in Perkins County in northwestern South Dakota in the United States, about 10miles 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.[2]
The dam is an embankment structure 145feet high and 12843feet long, with an elevation of 2318feet at the crest.[3] A catchment area of 3120mi2 lies above the dam site.[4] At full pool, the reservoir has a capacity of 468585acre feet, with a surface area of 12150acres.[4] Normal conservation water levels are much lower, at 81443acre feet.[2] Regular water discharges pass through an outlet works with a capacity of 600cuft/s, while flood flows are released through two spillways: a morning glory inlet with a capacity of 5700cuft/s, and an emergency overflow channel that can pass up to 127000cuft/s.[2] [5]
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.[2]