Garrison Dam and Lake Sakakawea

The U.S. Army Corps of Engineers completed construction of Garrison Dam in 1953 across the Upper Missouri River near Riverdale, North Dakota. It is the second-most upstream project of six projects built on the mainstem of the upper Missouri River which, in combination with dams on the river’s tributaries, reduce the risk of downstream flooding along the Missouri and Mississippi rivers. When not operating to reduce flood impacts, this mainstem system of dams is managed to balance hydropower generation, water supply, water quality, irrigation, fish and wildlife conservation, navigation, and recreation benefits. 

The River Basin Balancer Game offers insight into an inland waterway and a system of reservoirs, which are operated with a goal for serving each of the benefits, flood control, navigation, hydropower, irrigation, water supply, recreation, fish and wildlife, and water quality, for which many USACE reservoirs are authorized and constructed. Users can take charge of river operations and experience the unique challenges presented when managing reservoir operations in a variety of weather conditions across a geographically diverse basin.

Stop Aquatic Hitchhikers! Prevent invasive species Water Safety Reserve a campsite at USACE campgrounds at Purchase Navigation and Boating Maps from the Jefferson National Parks Association

Garrison Dam News

Garrison Dam Draft Environmental Assessment study open for public comment
The U.S. Army Corps of Engineers, Omaha District is releasing its Draft Environmental Assessment to evaluate measures to reduce unacceptable dam safety risks at Garrison Dam on the Missouri River in...


Location: Near Garrison, N.D., River Mile 1,389.9

Lake Sakakawea and Garrison Dam are located in McLean and Mercer counties, 75 miles north of Bismarck, ND, amongst the rolling prairie and badlands of Western North Dakota.  Lake Sakakawea is the third largest man-made lake in the United States at 178 miles long, with over 1,500 miles of shoreline. Statistics and more information about the project’s features are available here.

The U.S. Army Corps of Engineers oversees management of the public lands and waters of Lake Sakakawea, which provide a variety of benefits to the public which include: recreation, fish and wildlife, flood damage reduction, hydropower production, irrigation, municipal and industrial water intakes, water quality, and navigation.

The Corps has several partners (Federal, Tribal, State, County, and City) who operate campgrounds, parks, and marinas on Lake Sakakawea.

This graphic illustrates the how the water storage capacity of the six upper Missouri River dams compares among that of other USACE reservoirs in the continental United States
Garrison Dam near Riverdale, N.D. Lake Sakakawea, formed by the Garrison Dam is the third largest reservoir in the United States.
The trout pond near the Downstream Campground at Garrison Dam. The Trout Pond has been renovated.
The Garrison Dam West Tailrace Road, at Garrison Dam near Riverdale, N.D., which provides access to the Garrison Power Plant wing walls and west side of the tailrace area, is now open for public use. The area was closed for a road reconstruction project and to repair damages incurred during the flooding in 2011.

Operating for many benefits

Garrison Dam and Lake Sakakawea provide many benefits to the local and regional public and to the nation. These include reducing the loss of life and property damage from floods, producing hydropower, and providing water intakes for municipal and industrial uses. The storage and release of water also benefits recreation, irrigation, water quality, fish and wildlife, and river navigation.

The public lands and waters of also provide a wide variety of recreational activities, such as fishing, boating, and camping. USACE and several partners (federal, tribal, state, county, and city) operate campgrounds, parks, and marinas on the lake.


Fishing is the primary recreation activity at Lake Sakakawea. There are several boat ramps located around the lake, and most are in recreation or wildlife management areas. Shoreline Access Areas around the lake offer an additional access to the water’s edge. For information USACE-operated recreation at Lake Sakakawea visit

The Garrison Dam National Fish Hatchery and Visitor Center is located downstream of the dam. The Center’s  five 400-gallon aquariums provide  viewing of the fish of North Dakota in their environment.

The 14,739-acre Audubon National Wildlife Refuge  provides several exhibits featuring wetlands, native prairie, and the abundant wildlife that can be observed across the refuge.

The East Totten Trail Campground is among the several public recreation areas on Lake Sakakawea near Riverdale, N.D.
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 Getting Here:
  • From Bismarck: North Dakota, take Highway 83 north and turn left on Highway 200 west toward Riverdale.
  • From Minot: North Dakota, take Highway 83 south and turn right onto Highway 48. At intersection, turn right onto Highway 200 west toward Riverdale.
 Hunting and Fishing:

Public lands in the area of Garrison Dam offer great places for hunting pheasants, grouse, partridge, turkey, waterfowl, and deer. In addition, other areas may allow trapping/snaring ed.

Lake Sakakawea offers a wide-range of sport fishing including pike, walleye, and Chinook salmon.
Fishing regulations are established and enforced by the State of North Dakota and the Fort Berthold Indian Tribes Game & Fish Department.  

There are many Ice Fishing Access Areas located around Lake Sakakawea. (See the Ice Fishing Location Map)
Most are boat ramps but there are other areas that provide a legal means for the general public to access the water during the winter.

USACE has certain project restrictions for areas it directly operates (buildings, recreation, and day use areas) for hunting, trapping, and snaring.

 Visitor Center Schedule Information (Dates/Times):

Garrison Dam Project Office and Information Center Hours:

Monday thru Friday 7:30am to 4 pm.

  • U.S. Army Corps of Engineers
  • 201 1st ST, PO Box 527
  • Riverdale, North Dakota 58565

Phone: (701) 654-7411

Hours of operation:
9 a.m. to 5 p.m.
Sunday - Saturday
Beginning Labor Day
8 a.m. to 4 p.m.

 Dam and Powerplant Tour Schedule information (Dates/Times):
  • Due to increased security, visitors for powerhouse tours should arrive 15 minutes prior to the tour and visitors over 18 years old must show a government issued photo ID.

Reducing Flood Risk

During normal operations, when the region is not threatened by significant storms, USACE releases stored water through five penstock tunnels to generate power and balance reservoir levels for other uses. When reservoir levels are high and operations shift to reducing flood risks to downstream communities, most often during extreme storms when rain or snowmelt fill the reservoir, dam operators can release additional water through the three regulatory outlet tunnels and through the 28 gates that run across a concrete spillway on the dam’s southeast end.

In all, the spillway was designed to release 827,000 cubic feet of water per second if needed to preserve the integrity of the dam. This flow is the equivalent of filling over nine Olympic size swimming pools each second. In addition, the eight tunnels can collectively pass 136,000 cubic feet of water per second. These controlled, intentional flows are called “non-breach” releases and may be required in the future as a result of a rare but extreme flood.

For perspective, the largest release of water was 150,000 cubic feet of water per second through the tunnels and spillway in June 2011. It is important to understand that the dam is designed to release far more water.

Aerial image of the Garrison Dam Spillway, July 1, 2011.
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 Maintaining the dam

As part of its Dam Safety Program, Omaha District conducts detailed engineering analyses to ensure its dams are safe and that risks to the public, property, and the environment are minimized to the extent possible. Dam safety standards and practices are continually updated to improve the maintenance and operation of dams to ensure they can safely serve their original purposes. In addition, dam safety engineers across federal and state agencies share information as they learn about the performance of flood risk reduction structures built over many decades. They now use more precise, modern technologies and apply up-to-date science to reduce flood risk more effectively. Garrison Dam continues to operate as designed but is considered high risk because of the significant consequences of an unlikely uncontrolled reservoir releases on downstream populations, including twelve states and numerous urban centers along the Missouri River. Learn more about these risks and view inundation maps related to Garrison Dam on the National Inventory of Dams.

Omaha District completed several actions to improve and repair Garrison Dam after the flooding of 2011. Information the recently completed study and the recommended plan to improve the spillway is available here.


Garrison Dam was built in a region which served as a major transportation route. When the first fur traders arrived in the region in the 1700s, they found three Tribes of Indians settled there. The Hidatsa, Mandan, and the Arikara were farmers whose earth lodge villages served as major trading centers with the more nomadic tribes of the plains as well as travelers coming up the river.

In 1804, the Hidatsa villages on the Knife River hosted the expedition led by Captain Meriwether Lewis and Lieutenant William Clark, who had been commissioned by President Thomas Jefferson to explore the Louisiana Purchase from St. Louis to the Pacific. While at the villages, the enlisted a Canadian trapper named Toussaint Charboneau to serve as an interpreter and guide. Charboneau's wife, Sacajawea (Sakakawea - a Hidatsa word meaning Bird Woman) was a Shoshoni whose knowledge of the unknown land and people proved invaluable to Lewis and Clark and an important addition to the expedition. In honor of her courage, Lake Sakakawea was named for her.

The Lewis and Clark expedition opened the doorway to the West. Traders continued up the Missouri in increasing numbers setting up a number of small fur trading posts along the river. Federal soldiers became the next occupants of the territory as Fort Clark, Fort Abraham Lincoln, Fort Stevenson and Fort Buford were erected along the Missouri to protect steamboat traffic and settlers.

By the 1880s, the region opened to settlers. Many were farmers immigrating from northern Europe and Russia. In the Little Missouri River area, raising cattle became the primary industry. Future President Theodore Roosevelt tried his hand in the cattle business at his Elkhorn Ranch. Agriculture remained the mainstay of the economy in the 20th Century until the completion of Garrison Dam brought the recreation industry to Sakakawea County.