Black Eagle Dam

Black Eagle Dam
Black Eagle Dam in 2013
Official nameBlack Eagle Dam
LocationGreat Falls, Montana, U.S.
Coordinates47°31′11″N 111°15′47″W / 47.51972°N 111.26306°W / 47.51972; -111.26306
Construction beganSeptember 1890 (first dam);
April 1926 (second dam)
Opening dateDecember 1890 (first dam);
September 1927 (second dam)
Operator(s)NorthWestern Corporation
Dam and spillways
ImpoundsMissouri River
Height34.5 feet (10.5 m) (second dam)
Length782 feet (238 m) (second dam)
Reservoir
CreatesLong Pool
Power Station
Installed capacity18 MW
Annual generation142,590,000 KWh (2009)[1]

Black Eagle Dam is a hydroelectric gravity weir dam located on the Missouri River in the city of Great Falls, Montana.[2][3] The first dam on the site, built and opened in 1890, was a timber-and-rock crib dam.[4] This structure was the first hydroelectric dam built in Montana[5][6] and the first built on the Missouri River.[4] The dam helped give the city of Great Falls the nickname "The Electric City."[7] A second dam, built of concrete in 1926 and opened in 1927, replaced the first dam, which was not removed and lies submerged in the reservoir.[6][8] Almost unchanged since 1926,[9] the dam is 782 feet (238 m) long and 34.5 feet (10.5 m) high,[10] and its powerhouse contains three turbines capable of generating seven megawatts (MW) of power each.[2][11] The maximum power output of the dam is 18 MW.[10] Montana Power Company built the second dam, PPL Corporation purchased it in 1997 and sold it to NorthWestern Corporation in 2014. The reservoir behind the dam has no official name, but was called the Long Pool for many years.[12] The reservoir is about 2 miles (3.2 km) long,[13] and has a storage capacity of 1,710 acre-feet (2,110,000 m3)[14] to 1,820 acre-feet (2,240,000 m3) of water.[15]

The dam is a "run-of-the-river" dam because it can generate electricity without needing to store additional water supplies behind the dam.[2]

  1. ^ "Black Eagle". Carbon Monitoring for Action. Retrieved 2018-04-26.
  2. ^ a b c "Black Eagle Dam Open to Public," KFBB-TV, August 29, 2009". Archived from the original on 2011-07-20. Retrieved 2011-04-12.
  3. ^ "Black Eagle Falls (Black Eagle Dam) is the only one in the city." See: "Great Falls Scores a Number of Firsts in Montana." Great Falls Tribune. March 20, 2005.
  4. ^ a b Peterson, p. 59.
  5. ^ Marcosson, p. 145; Holmes, Dailey, and Walter, p. 397.
  6. ^ a b McCormick, Mary (September 1996). "Black Eagle Hydroelectric Facility" (PDF). Historic American Engineering Record. Washington, D.C.: Library of Congress. Retrieved February 12, 2022.
  7. ^ "City's Past Rooted in the River That Runs Through It." Great Falls Tribune. March 24, 2002.
  8. ^ Cite error: The named reference Peterson61 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Peterson63 was invoked but never defined (see the help page).
  10. ^ a b PPL Montana, Form S-4, p. A-23.
  11. ^ Cite error: The named reference HallTour was invoked but never defined (see the help page).
  12. ^ Peterson, p. 116.
  13. ^ Peterson, p. 82.
  14. ^ "Black Eagle Dam," PPL Montana, 2011. Archived 2011-07-15 at the Wayback Machine Accessed 2011-04-05.
  15. ^ "The FERC order issuing a new license dated September 27, 2000, states that the Black Eagle reservoir has a storage capacity of 1820 AF at normal maximum water surface elevation of 3290 feet." See: Water Right Solutions, Inc., p. 4. Archived 2011-10-03 at the Wayback Machine