Releases from Gavins Point Dam will be reduced in late November as flow support to navigation ends. Releases are currently 25,500 cubic feet per second (cfs).

“We will continue to make releases from Gavins Point Dam to provide flow support at a level 4,500 cfs less than full service, through the end of the navigation flow support season, which ends on Dec. 1 at the mouth of the Missouri River,” said John Remus, chief of the USACE, Missouri River Water Management Division.

Release reductions to the winter rate are scheduled to begin around Nov. 22. Releases will be reduced by 3,000 cfs each day until reaching a rate of 15,000 cfs. The rate of reduction will then slow to 1,000 cfs every five days until reaching the winter release. Fort Randall Dam releases will be stepped down in a similar manner, approximately one day prior to the Gavins Point reductions. 

“Based on the Sept. 1 Mainstem Reservoir System storage check, releases from Gavins Point Dam for the 2025-2026 winter will be at the minimum rate of 12,000 cfs,” said Remus.

“Intake operators in the lower river should take measures to now ensure access to the water can be maintained during ice formation and river stage fluctuations. Although releases may be temporarily increased to provide additional room for water when extremely cold temperatures are expected, ice formation can cause lower-than-expected stages on the Missouri River which can negatively impact access for intake structures.”

October runoff in the Missouri River basin above Sioux City, Iowa, was 1.1 million-acre-feet (MAF), which is 89% of average. Runoff was below average in the Fort Peck, Garrison, and Fort Randall reaches and above normal for the remaining reaches. Based on the most recent Drought Monitor, about 54% of the Basin is currently in abnormally dry or drought conditions. Those areas in drought conditions are expected to remain in drought conditions through the end of January. The 2025 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 19.7 MAF, 77% of average.

Reservoir studies indicate System storage will be below the base of the Flood Control Zone at the start of the 2026 runoff season. System storage is forecast to be about 48.8 MAF, which is 7.3 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 six to twelve feet below the base of their respective flood control zones on March 1.

Releases from Gavins Point Dam will be reduced in late November as flow support to navigation ends. Releases are currently 25,500 cubic feet per second (cfs).

“We will continue to make releases from Gavins Point Dam to provide flow support at a level 4,500 cfs less than full service, through the end of the navigation flow support season, which ends on Dec. 1 at the mouth of the Missouri River,” said John Remus, chief of the USACE, Missouri River Water Management Division.

Release reductions to the winter rate are scheduled to begin around Nov. 22. Releases will be reduced by 3,000 cfs each day until reaching a rate of 15,000 cfs. The rate of reduction will then slow to 1,000 cfs every five days until reaching the winter release. Fort Randall Dam releases will be stepped down in a similar manner, approximately one day prior to the Gavins Point reductions. 

“Based on the Sept. 1 Mainstem Reservoir System storage check, releases from Gavins Point Dam for the 2025-2026 winter will be at the minimum rate of 12,000 cfs,” said Remus.

“Intake operators in the lower river should take measures to now ensure access to the water can be maintained during ice formation and river stage fluctuations. Although releases may be temporarily increased to provide additional room for water when extremely cold temperatures are expected, ice formation can cause lower-than-expected stages on the Missouri River which can negatively impact access for intake structures.”

October runoff in the Missouri River basin above Sioux City, Iowa, was 1.1 million-acre-feet (MAF), which is 89% of average. Runoff was below average in the Fort Peck, Garrison, and Fort Randall reaches and above normal for the remaining reaches. Based on the most recent Drought Monitor, about 54% of the Basin is currently in abnormally dry or drought conditions. Those areas in drought conditions are expected to remain in drought conditions through the end of January. The 2025 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 19.7 MAF, 77% of average.

Reservoir studies indicate System storage will be below the base of the Flood Control Zone at the start of the 2026 runoff season. System storage is forecast to be about 48.8 MAF, which is 7.3 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 six to twelve feet below the base 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, at a flow support level 4,500 cfs below full-service for the second half of the 2025 navigation season. Flow support is expected to end on the dates indicated below:

Reservoir Forecasts:

• Gavins Point Dam
  • Average releases past month – 24,400 cfs
  • Current release rate – 25,500 cfs (as of Nov. 5)
  • Forecast average release rate – 22,600 cfs (November)
  • End-of-October reservoir level – 1207.8 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 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 – 22,200 cfs
  • End-of-October reservoir level – 1344.5 feet
  • Forecast end-of-November reservoir level – 1336.9 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 near 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 – 13,300 cfs
  • Forecast average release rate – 12,700 cfs
  • Forecast reservoir level – 1420.5 feet
• Oahe Dam
  • Average releases past month – 13,300 cfs
  • Forecast average release rate – 13,200 cfs
  • End-of-October reservoir level – 1600.4 feet
  • Forecast end-of-November reservoir level – 1600.5 feet
• Garrison Dam
  • Average releases past month – 13,800 cfs
  • Current release rate – 14,000 cfs
  • Forecast average release rate – 14,000 cfs
  • End-of-October reservoir level – 1831.3 feet
  • Forecast end-of-November reservoir level – 1830.2 feet
• Fort Peck Dam
  • Average releases past month – 4,200 cfs
  • Current release rate – 4,000 cfs
  • Forecast average release rate – 4,000 cfs
  • End-of-October reservoir level – 2222.3 feet
  • Forecast end-of-November reservoir level – 2221.7 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 539 million kWh of electricity in October. Typical energy generation for October is 813 million kWh. The power plants are projected to generate 7.7 billion kWh of electricity this year, compared to the long-term average of 9.4 billion kWh.

To view the detailed three-week release forecast for the mainstem dams, go to https://go.mil/mr-3wk-fcast.