Gavins Point Dam Releases To Be Reduced To Winter Release Rate In Late November

Six public meetings were held during the week of Oct. 24 to present current hydrologic conditions and the planned operation of the Missouri River mainstem reservoir system for the remainder of 2022.

The public meetings were held in six locations in the Missouri River basin and a virtual public meeting was held Nov. 3. The meetings included draft plans for regulating the system in 2023.

“We will continue to make releases from Gavins Point Dam to provide flow support at a level 500 cubic feet per second above minimum service, through the end of the navigation flow support season,” said John Remus, chief of the USACE, Missouri River Basin Water Management Division. “The flow support season will end three days early, on Nov. 28, at the mouth of the Missouri River.”

Gavins Point releases are currently 30,000 cfs. Release reductions to the winter rate of 12,000 cfs were scheduled to begin around Nov. 19. Releases will be gradually reduced by 3,000 cfs each day until reaching a rate of 15,000 cfs. Releases will then be paused before stepping down 1,000 cfs every five days to the winter release. Fort Randall releases will be stepped down in a similar manner, approximately one day prior to the Gavins Point reductions.

“Winter releases from Gavins Point Dam for the 2022-2023 winter will be similar to last winter,” said Remus. “Intake operators in the lower river should be taking measures to assure access they can maintain access to the water.”

Despite recent rainfall events during October in various parts of the upper Basin, runoff was below normal. October runoff was 0.7 million-acre-feet above Gavins Point Dam, which is 73 percent of normal. Approximately 90 percent 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 and expanding across most of the upper Basin. The 2022 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 19.4 MAF, 76 percent of average.

Reservoir studies indicate System storage will be well below normal at the start of the 2023 runoff season. System storage is forecast to be about 46.5 MAF, more than 9 MAF into the System’s Carryover and Multiple Use Zone. This means that the Fort Peck, Garrison, and Oahe reservoirs are expected to be approximately 12 to 15 feet below the base of their respective flood control zones on March 1.

Reservoir Forecasts:

Fort Peck Dam

– Average releases past month – 4,100 cfs

– Current release rate – 4,000 cfs

– Forecast average release rate – 4,000 cfs

– End-of-October reservoir level – 2219.9 feet

– Forecast end-of-November reservoir level – 2220.1 feet

Gavins Point Dam

– Average releases past month – 31,800 cfs

– Current release rate – 30,000 cfs (as of November 1)

– Forecast average release rate – 25,700 cfs (November)

– End-of-October reservoir level – 1208.0 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 15,000 cfs beginning around November 19 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 – 29,900 cfs

– End-of-October reservoir level – 1343.1 feet

– Forecast end-of-November reservoir level – 1337.3 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 – 20,000 cfs

– Forecast average release rate – 17,200 cfs

– Forecast reservoir level – 1420.6 feet

Oahe Dam

– Average releases past month – 21,000 cfs

– Forecast average release rate – 17,000 cfs

– End-of-October reservoir level – 1590.9 feet

– Forecast end-of-November reservoir level – 1590.1 feet

Garrison Dam

– Average releases past month – 14,000 cfs

– Current release rate – 15,000 cfs

– Forecast average release rate – 15,000 cfs

– End-of-October reservoir level – 1833.3 feet

– Forecast end-of-November reservoir level – 1832.2 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.

The six mainstem power plants generated 689 million kWh of electricity in October. Typical energy generation for October is 817 million kWh. The power plants are projected to generate 7.5 billion kWh of electricity this year, compared to the long-term average of 9.4 billion kWh.

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