Gavins Point Dam releases to be reduced to fall water supply rate

OMAHA, Neb. -- Gavins Point Dam releases will be reduced in early November as flow support to navigation ends. Releases are currently 24,500 cubic feet per second. “We will continue to make releases from Gavins Point Dam to provide flow support at minimum service through the end of the navigation flow support season. Due to the persisting drought in the upper Basin, the season is being shortened and will be ending on Nov. 15 at the mouth of the Missouri River,” said John Remus, chief of the USACE, Missouri River Water Management Division. The normal season ending date is Dec. 1.

Release reductions to the fall rate began Nov. 6. Releases will be reduced by 3,000 cfs each day until reaching a rate of 9,000 cfs. A fall water supply release, which last occurred in 2008, is another drought conservation measure that occurs from the end of a shortened navigation flow support season until the winter release begins on Dec. 1. Fort Randall 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 2026-2027 winter will be at the minimum rate of 12,000 cfs,” said Remus. “Intake operators in the lower river should be taking measures to assure they can maintain access to the water. Releases may be temporarily increased to provide additional water when extremely cold temperatures cause ice formation and lower-than-expected stages on the Missouri River.”

October runoff in the Missouri River basin above Sioux City, Iowa, was 0.7 million-acre-feet (MAF), which is 61% of average. Runoff was below normal in all the reaches except Sioux City, which was near normal. Based on the most recent Drought Monitor, about 60% of the Basin is currently in abnormally dry or drought conditions. Drought conditions through January 2027 are expected to persist or expand in Montana, Wyoming, and the western Dakotas but could improve in central South Dakota, the eastern Dakotas, and western Nebraska. The 2026 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 16.2 MAF, 63% of average.

Reservoir studies indicate System storage will be below the base of the flood control storage zone at the start of the 2027 runoff season. System storage is forecast to be about 44.8 MAF, which is 11.3 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 14 to 16 feet below the base of their respective flood control zones on March 1, 2027.

Fall Release Rate

Gavins Point releases can be reduced to water supply release rates during extended droughts when the navigation flow support season ends earlier than Dec. 1 per the Master Manual. Gavins Point releases may be reduced to the water supply release of 9,000 cfs for approximately two weeks prior to the winter release rate beginning on Dec. 1. Downstream tributary flows will be monitored during this period and releases will be adjusted as necessary if there is not sufficient flow downstream of Gavins Point.

Navigation

Gavins Point Dam releases are being set to provide navigation flow support at minimum service at all four target locations (Sioux City, Omaha, Nebraska City, and Kansas City). As previously announced, the July 1 System storage check indicated a shortened flow support season, at minimum service level for the second half of the 2026 navigation season. Flow support is scheduled to end on the dates indicated below:

Location End Date

Sioux City, Iowa Nov. 6 Omaha, Neb. Nov. 8 Kansas City, Mo. Nov. 11 Mouth near St. Louis, Mo. Nov. 15

Winter Release Rate As per the criteria in the Master Manual, the winter release rate is determined from the Sept. 1 System storage. Per the Sept.1 System storage, winter releases from Gavins Point Dam will be at least 12,000 cubic feet per second. In anticipation of the low winter releases, a letter was sent to water users below Gavins Point Dam making them aware of the planned releases and encouraging them to assess the risk to their facilities.

Reservoir Forecasts:

• Gavins Point Dam

  • Average releases past month – 24,500 cfs
  • Current release rate – 24,500 cfs (as of Nov. 3)
  • Forecast average release rate – 12,700 cfs (November)
  • End-of-October reservoir level – 1208.0 feet
  • Forecast end-of-November reservoir level – 1207.6 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 9,000 cfs beginning around November 6 at a rate of 3,000 cfs per day.

• Fort Randall Dam

  • Average releases past month – 22,800 cfs
  • End-of-October reservoir level – 1339.3 feet
  • Forecast end-of-November reservoir level – 1337.1 feet
  • Notes: Releases will be reduced in early 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 – 9,100 cfs
  • Forecast average release rate – 8,500 cfs
  • Forecast reservoir level – 1420.7 feet

• Oahe Dam

  • Average releases past month – 9,100 cfs
  • Forecast average release rate – 8,600 cfs
  • End-of-October reservoir level – 1592.3 feet (up 0.3 feet since Sept. 30)
  • Forecast end-of-November reservoir level – 1593.3 feet

• Garrison Dam

  • Average releases past month – 12,900 cfs
  • Current release rate – 13,000 cfs
  • Forecast average release rate – 13,000 cfs
  • End-of-October reservoir level – 1823.8 feet (down 0.5 feet since Sept. 30)
  • Forecast end-of-November reservoir level – 1823.3 feet

• Fort Peck Dam

  • Average releases past month – 7,000 cfs
  • Current release rate – 7,000 cfs
  • Forecast average release rate – 7,000 cfs
  • End-of-October reservoir level – 2221.4 feet (down 0.8 feet since Sept. 30)
  • Forecast end-of-November reservoir level – 2220.4 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 501 million kWh of electricity in October. Typical energy generation for October is 808 million kWh. The power plants are projected to generate 7.0 billion kWh of electricity this year, compared to the long-term average of 9.3 billion kWh. To view the detailed three-week release forecast for the mainstem dams, go tohttps://go.mil/mr-3wk-fcast.

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