News Releases

Gavins Point Dam releases to be reduced in late November

Missouri River Water Management
Published Nov. 5, 2021

Fall public meetings provide an update on current year's runoff and reservoir operations as well as planned operations for the next year's runoff season. The 2021 Runoff season is among the 10 lowest runoff years in more than 120 years of recordkeeping. Meetings were held October 25-28, 2021. The Annual Operating Plan for the next year's runoff season is released for public comment in October, presented at the public meetings and finalized at the end of the calendar year.

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.

Public meetings were held in seven locations along the Missouri River during the week of Oct. 25.

The U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division held these meetings to present current hydrologic conditions and planned operation of the Missouri River mainstem reservoir system for the remainder of 2021. Public meetings are held each fall and spring to update the region on current conditions and planned operations. The meetings included draft plans for operating the system during 2022.

“We will continue to make releases from Gavins Point Dam to provide flow support at an intermediate service level, 1,500 cubic feet per second (cfs) less than full service, through the end of the navigation flow support season,” said John Remus, chief of the USACE, Missouri River Water Management Division.

Gavins Point releases are currently 28,000 cfs. Release reductions to the winter rate of 12,000 cfs are scheduled to begin around Nov. 22. Releases will be gradually reduced by 3,000 cfs each day until reaching a rate of 14,000 cfs. Releases will then be paused before stepping down 1,000 cfs every five days to the winter release. The navigation flow support season normally ends on Dec. 1 at the mouth of the Missouri River. Fort Randall releases will be stepped down in a similar manner, approximately one day prior to the Gavins Point reductions.

 Updated reservoir studies indicate that the service level for navigation support for the first half of the 2022 navigation season will likely be at minimum service levels.

Despite several significant rainfall events during October in various parts of the upper Basin, runoff was below normal. Approximately 82% of the Missouri River basin is experiencing some form of abnormally dry conditions or drought according to the National Drought Mitigation Center. The seasonal drought outlook, which extends through the end of January, shows drought conditions persisting across most of the upper Basin.

The 2021 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 15.0 million acre-feet (MAF), 58% of average. If realized, this runoff would be the 10th lowest runoff in 123 years of record-keeping.

Reservoir studies indicate System storage will be well below normal at the start of the 2022 runoff season. System storage is forecast to be about 48 MAF, more than 8 MAF into the System’s conservation zone. This means that the Fort Peck, Garrison, and Oahe reservoirs are expected to be 10 to 12 feet below the bases of their respective flood control zones on March 1.

Navigation

As previously announced, the July 1 System storage check indicated a full-length flow support season but at an intermediate flow support level, 1,500 cfs below full-service, for the second half of the 2021 navigation season. Full-service flow support is designed to work in tandem with the Missouri River Bank Stabilization and Navigation Project to provide a 9-foot deep by 300-foot wide navigation channel from Sioux City, Iowa to the mouth of the river near St. Louis, Missouri. Flow support is expected to end on the dates indicated below:

  • Location                                             End Date 
  • Sioux City, Iowa                                  November 22
  • Omaha, Nebraska                              November 24
  • Nebraska City, Nebraska                   November 25
  • Kansas City, Missouri                         November 27
  • Mouth near St. Louis, Missouri           December 1

Fall Public Meetings

A recording of the Bismarck, North Dakota meeting held on Oct. 25 is available online at the following address:
https://www.nwd.usace.army.mil/MRWM/Public-Meetings/

Reservoir Forecasts:

  • Gavins Point Dam
    • Average releases past month – 30,900 cfs
    • Current release rate – 28,000 cfs (as of Nov. 1)
    • Forecast release rate – 23,900 cfs (November)
    • End-of-October reservoir level – 1208.1 feet
    • Forecast end-of-November reservoir level – 1207.5 feet
    • Notes: Releases will be adjusted as necessary to meet all downstream navigation targets until the end of the navigation flow support season. The Gavins Point release will be reduced to 14,000 cfs beginning around Nov. 22 at a rate of 3,000 cfs per day, then at a rate of 1,000 cfs every 5 days to the winter release rate of 12,000 cfs.
  • Fort Randall Dam
    • Average releases past month – 29,100 cfs
    • End-of-October reservoir level – 1346.2 feet
    • Forecast end-of-November reservoir level – 1337.1 feet
    • Notes: Releases will be stepped down near the end of November, approximately one day prior to the Gavins Point reductions as necessary to maintain the desired reservoir elevation at Gavins Point. The Fort Randall pool is normally drawn down to 1337.5 feet in the fall to provide space for winter hydropower generation at Oahe and Big Bend. The annual drawdown will continue in November.
  • Big Bend Dam
    • Average releases past month – 21,500 cfs
    • Forecast average release rate – 14,800 cfs
    • Forecast reservoir level – 1420.7 feet
  • Oahe Dam
    • Average releases past month – 22,000 cfs
    • Forecast average release rate – 14,700 cfs
    • End-of-October reservoir level – 1596.9 feet
    • Forecast end-of-November reservoir level – 1596.4 feet
  • Garrison Dam
    • Average releases past month – 13,500 cfs
    • Current release rate – 13,500 cfs
    • Forecast average release rate – 13,000 cfs
    • End-of-October reservoir level – 1830.4 feet
    • Forecast end-of-November reservoir level – 1829.6 feet
  • Fort Peck Dam
    • Average releases past month – 5,400 cfs
    • Current release rate – 5,000 cfs
    • Forecast average release rate – 5,000 cfs
    • End-of-October reservoir level – 2227.1 feet
    • Forecast end-of-November reservoir level – 2226.4 feet

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 708 million kWh of electricity in October. Typical energy generation for October is 819 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)

 

 

On October 31

Change in October

On October 31

% of 1967-2020 Average

Change in October

Fort Peck

2227.1

-0.6

13,387

92

-125

Garrison

1830.4

-0.8

15,673

88

-201

Oahe

1596.9

-1.8

15,612

88

-503

Big Bend

1421.0

+0.4

1,691

99

+21

Fort Randall

1346.2

-6.7

2,727

82

-505

Gavins Point

1208.0

+0.8

376

96

+21

 

 

Total

49,466

89

-1,292

 

WATER RELEASES AND ENERGY GENERATION FOR OCTOBER

 

Average Release in 1,000 cfs

Releases in 1,000 acre-feet

Generation in Million kWh

Fort Peck

5.4

330

49

Garrison

13.5

829

121

Oahe

22.0

1,350

196

Big Bend

21.5

1,325

75

Fort Randall

29.1

1,788

181

Gavins Point

30.9

1,902

86

 

 

Total

708

 


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

Release no. 21-049