Garrison Dam

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Garrison Dam
Garrison Dam aerial.jpg
Garrison Dam is located in North Dakota
Garrison Dam
Location of Garrison Dam
Country United States
Location Lake Sakakawea, at McLean / Mercer counties, North Dakota
Coordinates 47°29′55″N 101°24′43″W / 47.49861°N 101.41194°W / 47.49861; -101.41194Coordinates: 47°29′55″N 101°24′43″W / 47.49861°N 101.41194°W / 47.49861; -101.41194
Status Operational
Construction began 1947
Opening date 1953
Construction cost US$300 million
Dam and spillways
Type of dam Embankment, rolled earth-fill
Height 210 ft (64 m)
Length 11,300 ft (3,444 m)
Width (crest) 60 ft (18 m)
Width (base) 0.5 mi (1 km)
Dam volume 66,500,000 cu yd (50,842,898 m3)[1]
Spillway type Service, 28 controlled-gates
Spillway capacity 660,000 cu ft/s (18,689 m3/s)[2]
Total capacity 23,821,000 acre·ft (29.383 km3)[2]
Surface area 382,000 acres (1,546 km2)
Max. length 178 mi (286 km)
Normal elevation 1,854 ft (565 m) (max)
Power station
Commission date January 1956–October 1960[2]
Turbines 3 x 121.6 MW, 2 x 109.25 Francis type
Installed capacity 583.3 MW[3]
Annual generation 2,250 GWh[2]

Garrison Dam is an earth-fill embankment dam on the Missouri River in central North Dakota. At over two miles (3 km) in length, it is the fifth-largest earthen dam in the world, constructed by the U.S. Army Corps of Engineers from 1947-53.[4] The reservoir impounded by the dam is Lake Sakakawea, which extends to Williston and the confluence with the Yellowstone River, near the Montana border.

Garrison Dam is located between Riverdale and Pick City, named after the town of Garrison, directly north of the dam, across the reservoir. The dam is approximately midway between Bismarck and Minot, about 10 miles (16 km) west of U.S. highway 83.

Hydropower turbines at Garrison Dam have an electric power generating nameplate capacity of 583.3 megawatts. Average production of 240 megawatts serves several hundred thousand customers.

The construction on the dam necessitated the purchase of 152,360 acres (616.6 km2) in the Fort Berthold Reservation that would be flooded by the creation of Lake Sakakawea. These lands were owned by the Three Affiliated Tribes and were taken in 1947 for $5,105,625 (increased to $7.5 million in 1949). About 1700 residents were forcibly relocated, some to New Town, North Dakota.[5][6] Construction on the $300 million dam project began in 1947, and its embankment was enclosed in April 1953. The dam was dedicated by President Eisenhower two months later. Earthwork was completed in the fall of 1954 by the Corps of Engineers as part of a flood control and power generation project along the river.[3]

The Garrison Dam National Fish Hatchery is the world's largest walleye and northern pike producing facility and also works to restore endangered species, such as the pallid sturgeon.

In June 2011, in response to the 2011 Missouri River Floods, the dam was releasing over 140,000 cubic feet per second (4,000 m3/s), which greatly exceeded its previous record release of 65,000 cu ft/s (1,800 m3/s) set in 1997.[7] The first use of the emergency spillway due to flooding started on June 1, 2011 at 8:00am.[8]


  1. ^ "Garrison Dam/ Powerplant". U.S. Army Corps of Engineers. Retrieved 19 June 2011. 
  2. ^ a b c d "Summary of Engineering Data – Missouri River Main Stem System". Missouri River Division. U.S. Army Corps of Engineers. August 2010. Retrieved 2012-08-17. 
  3. ^ a b "Facts about Garrison Dam and power plant". U.S. Army Corps of Engineers. Retrieved 19 June 2011. 
  4. ^
  5. ^ "The History and Culture of the Mandan, Hidatsa, and Sahnish". State of North Dakota. Retrieved 12 Feb 2012. 
  6. ^ "The History and Culture of the Mandan, Hidatsa, and Sahnish:Garrison Dam". North Dakota Studies. Retrieved 26 September 2014. 
  7. ^ "Missouri River Mainstem Reservoir Bulletin" (pdf). Army Corps of Engineers. Retrieved 18 June 2011. 
  8. ^ Spillway spectacle -Minot Daily News

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