News Releases

Gavins Point Dam releases reduced to winter release rate

Missouri River Basin Water Management Division
Published Dec. 6, 2021
Runoff can enter the Missouri River anywhere and anytime in the basin. Only when runoff occurs in the upper Missouri River basin can it be captured by the mainstem system of dams. Even then, where runoff is captured depends upon where precipitation falls.

Runoff can enter the Missouri River anywhere and anytime in the basin. Only when runoff occurs in the upper Missouri River basin can it be captured by the mainstem system of dams. Even then, where runoff is captured depends upon where precipitation falls.

Missouri River Basin Regulated Watersheds

The areas highlighted purple show the areas where Missouri River runoff is managed by the six main stem reservoirs. The areas highlighted blue are within the Omaha District area of responsibility and include USACE and Bureau of Reclamation dams. The areas highlighted yellow are within the Kansas City District area of responsibility and include USACE and Bureau of Reclamation dams. The green and brown areas are all unregulated tributaries of the Missouri Basin.

The six dams on the main stem of the Missouri River capture runoff from parts of Montana, North Dakota, South Dakota, Wyoming, and northern Nebraska.

The six dams on the main stem of the Missouri River capture runoff from parts of Montana, North Dakota, South Dakota, Wyoming, and northern Nebraska.

The U.S. Army Corps of Engineers began reducing the Gavins Point releases to the winter release rate on Nov. 23, marking the end of flow support for the 2021 Missouri River navigation season.

“Releases from Gavins Point Dam are being reduced to the winter release of 12,000 cubic feet per second,” said John Remus, Chief of the Missouri River Basin Water Management Division.

“Releases from Gavins Point are currently 13,000 cfs and we will slowly reduce releases to 12,000 by December 8. We will closely monitor river conditions, and releases will be adjusted this winter as needed to lessen the impacts of river ice formation on stages in the lower river.”

As the colder, winter temperatures enter the basin, USACE will closely monitor Missouri River ice conditions between the System reservoirs and downstream of Gavins Point Dam for potential ice jams that could impact river stages and water intakes.

Runoff in the upper Missouri River Basin above Sioux City, Iowa, was 700,000 acre-feet during November, 66% of average. The 2021 calendar year runoff forecast is 15.0 million acre-feet, 58% of average. Average annual runoff is 25.8 MAF.

The total volume of water stored in the Missouri River mainstem reservoirs is currently 48.3 MAF, which is 7.8 MAF below the base of the System flood control storage zone. System storage is forecast to begin the 2022 runoff season at 47.7 MAF, which is 8.4 MAF below the base of the system flood control zone.

Releases from Fort Peck Dam were stepped up from 5,000 cfs to 9,000 cfs on Dec. 6 and will be held at that rate through December. Releases from Garrison Dam were increased from 13,000 cfs to 16,000 cfs on Dec. 5. Releases from Garrison are typically set near 16,000 cfs prior to the river freeze-in to reduce the risk of ice-induced flooding in the Bismarck area. Releases will remain at that rate in December. Releases at Fort Peck and Garrison dams are being adjusted as a storage-balancing measure in the upper reservoirs.

Mountain and Plains Snowpack

Mountain snowpack in the upper Missouri River Basin is accumulating at well-below average levels. About 25% of the mountain snowpack typically accumulates by Dec. 1, and normally peaks near April 15.  While the mountain snowpack is currently below average, it is too early in the season to make a projection of the final 2022 mountain snowpack. Additionally, plains snowpack in the upper Missouri River Basin is sparse.

2020-2021 Annual Operating Plan

The comment period for the 2020-2021 Annual Operating Plan ended Nov. 24. The final AOP is scheduled for publication by the end of 2021 and will be posted online with other Missouri Basin Water Management Reports.

Monthly Water Management Conference Calls

Monthly water management calls will begin in January 2022.

Reservoir Forecasts

  • Gavins Point Dam
    • Average releases past month – 26,300 cfs
    • Current release rate – 14,000 cfs
    • Forecast release rate – 12,000 cfs
    • End-of-November reservoir level – 1207.7 feet
    • Forecast end-of-December reservoir level – 1207.5 feet
    • Notes: Releases were reduced to 14,000 cfs on Nov. 29. The winter release rate will be 12,000 cfs based on the Sept. 1 System storage check and may be adjusted to lessen the impacts of winter ice formation.
       
  • Fort Randall Dam
    • Average releases past month – 22,700 cfs
    • End-of-November reservoir level – 1336.9 feet
    • Forecast end-of-December reservoir level – 1339.5 feet
    • Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. The reservoir is normally drawn down to 1337.5 feet in the fall to provide space for winter hydropower generation at Oahe and Big Bend.
       
  • Big Bend Dam
    • Average releases past month – 15,700 cfs
    • Forecast average release rate – 13,100 cfs
    • Forecast reservoir level – 1420.4 feet
       
  • Oahe Dam
    • Average releases past month – 15,200 cfs
    • Forecast average release rate – 13,000 cfs
    • End-of-November reservoir level – 1596.3 feet
    • Forecast end-of-December reservoir level – 1596.6 feet
       
  • Garrison Dam
    • Average releases past month – 12,900 cfs
    • Current release rate – 13,000 cfs
    • Forecast average release rate – 16,000 cfs
    • End-of-November reservoir level – 1829.5 feet
    • Forecast end-of-December reservoir level – 1828.3 feet
    • Notes – Releases will be increased to 16,000 cfs on Dec. 6, prior to the river freeze-in at Bismarck, North Dakota.
       
  • Fort Peck Dam
    • Average releases past month – 5,200 cfs
    • Current release rate – 5,000 cfs
    • Forecast average release rate – 9,000 cfs
    • End-of-November reservoir level – 2226.6 feet
    • Forecast end-of-December reservoir level – 2224.9 feet
    • Notes: Releases will increased to 9,000 cfs by December 6.

The forecast reservoir releases and elevations discussed above are not definitive. Additional precipitation, lack of precipitation or other circumstances could cause adjustments to the reservoir release rates.

Hydropower

The six mainstem power plants generated 524 million kWh of electricity in November. Typical energy generation for November is 749 million kWh. The power plants are projected to generate 8.6 billion kWh of electricity this year, compared to the long-term average of 9.5 billion kWh.

To view the detailed three-week release forecast for the mainstem dams, go to http://go.usa.gov/xVgWr.

 

MISSOURI RIVER MAINSTEM RESERVOIR DATA

 

Pool Elevation
(feet above mean sea level)

 Water in Storage
(1,000 acre-feet)

 

On November 30

Change in November

On November 30

% of 1967-2020 Average

Change in November

Fort Peck

2226.6

-0.5

13,298

92

-89

Garrison

1829.6

-0.8

15,401

86

-272

Oahe

1596.5

-0.4

15,446

87

-166

Big Bend

1420.7

-0.3

1,668

98

-23

Fort Randall

1336.9

-9.3

2,163

65

-564

Gavins Point

1207.8

-0.2

368

94

-8

 

 

Total

48,344

87

-1,122

 

WATER RELEASES AND ENERGY GENERATION FOR NOVEMBER

 

Average Release in 1,000 cfs

Releases in 1,000 acre-feet

Generation in Million kWh

Fort Peck

5.2

309

46

Garrison

12.9

767

113

Oahe

15.3

907

128

Big Bend

15.7

932

53

Fort Randall

22.7

1,353

129

Gavins Point

26.3

1,563

54

 

 

Total

523


Contact
Eileen Williamson
402-996-3802
eileen.l.williamson@usace.army.mil

Release no. 21-068