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Madison Dam

Coordinates: 45°28′12″N 111°38′18″W / 45.47012°N 111.63831°W / 45.47012; -111.63831
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(Redirected from Ennis Lake)
Madison Dam
Madison Dam, January 2015
Madison Dam is located in Montana
Madison Dam
Location of Madison Dam in Montana
Madison Dam is located in the United States
Madison Dam
Madison Dam (the United States)
CountryUnited States
LocationMadison County, Montana
Coordinates45°28′12″N 111°38′18″W / 45.47012°N 111.63831°W / 45.47012; -111.63831
PurposeHydroelectric, Flood Control, Water Supply, Recreation
Opening date1906
Owner(s)PPL MONTANA, LLC
Operator(s)NorthWestern Corporation
Dam and spillways
Type of damTimber crib
Height39 ft (12 m)
Length257 ft (78 m)
Spillway capacity7,700 cubic feet per second (220 m3/s)
Reservoir
CreatesEnnis Lake
Total capacity42,053 acre⋅ft (51,872,000 m3)
Maximum length2.6 mi (4.2 km)
Normal elevation4,820 ft (1,469 m)[1]
Installed capacity9 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]

References

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  1. ^ U.S. Geological Survey Geographic Names Information System: Madison Dam
  2. ^ 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)
  3. ^ "Madison Dam". Archived from the original on 2012-07-11. Retrieved 2012-08-14.
  4. ^ "Ennis Lake". Retrieved 2022-02-26.
  5. ^ "Ennis Lake, Montana, USA Vacation Info".
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