Madison Dam
| Madison Dam | |
|---|---|
 Madison Dam, January 2015 | |
| Location | Madison County, Montana |
| Purpose | Hydroelectric, Flood Control, Water Supply, Recreation |
| Owner(s) | PPL MONTANA, LLC |
| Operator(s) | NorthWestern Corporation |
| Dam and spillways | |
| Type of dam | Timber Crib |
| Spillway capacity | 7700 cfs |
| Reservoir | |
| Total capacity | 42053 ac.ft. |
Madison Dam is a hydroelectric dam 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 high and 257 feet long at its crest,[1] placed into the narrows of Bear Trap Canyon. As one of eight PPL Montana hydro projects, it has a generating capacity of nine megawatts in a run-of-the-river configuration.[2] 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 long and has a maximum storage capacity of 42,053 acre-feet.[3] The lake is relatively shallow and warms significantly during the summer, which tends to decrease fish populations.[4] The lake still support recreational fishing for brown trout and rainbow trout, camping, boating, and white-water rafting in Bear Trap Canyon downstream (north) of the dam.[5]
References
Coordinates: 45°28′12″N 111°38′18″W / 45.47012°N 111.63831°W