| Grassy Lake Dam | |
|---|---|
 | |
  Location of Grassy Lake Dam in Wyoming | |
| Location | Teton County, Wyoming, near Yellowstone National Park |
| Coordinates | 44°07′51.52″N 110°49′07.77″W / 44.1309778°N 110.8188250°W |
| Construction began | 1937 |
| Opening date | 1939 |
| Operator(s) | U.S. Bureau of Reclamation |
| Dam and spillways | |
| Type of dam | Zoned earthfill dam |
| Impounds | Grassy Creek |
| Height | 118 ft (36 m) |
| Length | 1,170 ft (360 m) |
| Spillway capacity | Ungated bathtub |
| Reservoir | |
| Creates | Grassy Creek Reservoir |
| Total capacity | 15,200 acre-feet (0.0187 km3) |
| Catchment area | 3.65 sq mi (9.5 km2)[1] |
Grassy Lake Dam is a small dam operated by the U.S. Bureau of Reclamation in Teton County, Wyoming, immediately to the south of Yellowstone National Park. The dam lies in a corridor of Caribou-Targhee National Forest that runs between Yellowstone and Grand Teton National Parks. The dam structure and outlets are within a few hundred feet of the south boundary of Yellowstone. The zoned earthfill dam was built between 1937 and 1939 as part of the Minidoka Project, which provides water to irrigate farmland in Idaho's Snake River Plain.[1]
The dam provides only water storage, impounding 15,200 acre-feet (0.0187 km3). Given the small catchment area of Grassy Creek, inflow is augmented by a 0.7-mile (1.1 km) ditch that moves water from Cascade Creek into the reservoir.[1]
- ^ a b c "Grassy Lake Dam". Bureau of Reclamation. Archived from the original on 26 September 2012. Retrieved 4 May 2011.