| Madison Dam | |
|---|---|
 Madison Dam, January 2015 | |
  Location of Madison Dam in Montana  Madison Dam (the United States) | |
| Country | United States |
| Location | Madison County, Montana |
| Coordinates | 45°28′12″N 111°38′18″W / 45.47012°N 111.63831°W |
| Purpose | Hydroelectric, Flood Control, Water Supply, Recreation |
| Opening date | 1906 |
| Owner(s) | PPL MONTANA, LLC |
| Operator(s) | NorthWestern Corporation |
| Dam and spillways | |
| Type of dam | Timber crib |
| Height | 39 ft (12 m) |
| Length | 257 ft (78 m) |
| Spillway capacity | 7,700 cubic feet per second (220 m3/s) |
| Reservoir | |
| Creates | Ennis Lake |
| Total capacity | 42,053 acre⋅ft (51,872,000 m3) |
| Maximum length | 2.6 mi (4.2 km) |
| Normal elevation | 4,820 ft (1,469 m)[1] |
| Installed capacity | 9 MW |
Madison Dam is a hydroelectric dam on the Madison River in Madison County, Montana, in the southwestern part of the state.
The timber-crib dam was constructed in 1906 as a replacement for a similar 1901 dam and powerhouse on the same site. The dam is 39 feet (12 m) high and 257 feet (78 m) long at its crest,[2] placed into the narrows of Bear Trap Canyon. As one of eight PPL Montana hydro projects, it has a generating capacity of 9 megawatts (12,000 hp) in a run-of-the-river configuration.[3] Montana Power Company acquired the dam in 1912 as part of a merger, PPL Corporation purchased it in 1997 and sold it to NorthWestern Corporation in 2014.
The reservoir it creates, Ennis Lake, is 2.6 miles (4.2 km) long and has a maximum storage capacity of 42,053 acre-foot (51,872,000 m3).[2] The lake is relatively shallow and warms significantly during the summer, which tends to decrease fish populations.[4] The lake supports recreational fishing for brown trout and rainbow trout, camping, boating, and white-water rafting in Bear Trap Canyon downstream (north) of the dam.[5]
- ^ U.S. Geological Survey Geographic Names Information System: Madison Dam
- ^ a b "Archived copy". Archived from the original on 2017-10-19. Retrieved 2016-10-04.
{{cite web}}: CS1 maint: archived copy as title (link) - ^ "Madison Dam". Archived from the original on 2012-07-11. Retrieved 2012-08-14.
- ^ "Ennis Lake". Retrieved 2022-02-26.
- ^ "Ennis Lake, Montana, USA Vacation Info".