Abnormally dry or drought conditions are present across 73% of the Basin, with drought conditions likely to persist or worsen through November.

August runoff was 1.2 MAF, or million acre-feet, 86% of average above Sioux City. The updated 2024 calendar year forecast for the upper Basin is 23.8 MAF, 92% of average. Average annual runoff for the upper Basin is 25.7 MAF.

“August rainfall was generally near normal across most of the Missouri River Basin, with isolated areas of above normal precipitation in every state except Nebraska. Nebraska was generally below average with most of northern Nebraska measuring 50% of normal precipitation,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division.

“Runoff in the Fort Peck and Fort Peck to Garrison reaches were well-below average while runoff in the reaches between Garrison Dam and Sioux City were all above average,” Remus added.

As of Sept. 1, the total volume of water stored in the System was 55.1 MAF, which is 1.0 MAF below the base of the System’s flood control zone. System storage is expected to continue to decline through the fall. The updated reservoir studies indicate that the System storage is expected to be approximately 4.7 MAF below the base of flood control at the start of the 2025 runoff season.

Fort Peck and Garrison releases will be reduced to the fall release rates in mid-September. Fort Peck releases will be lowered from 9,000 cfs to 4,000 cfs starting on Sept. 16. Garrison releases will be stepped down from 22,000 cfs to 14,000 cfs starting on Sept. 16.

Navigation

Gavins Point Dam releases are being set to provide navigation flow support at a level 500 cfs below full service at all four target locations (Sioux City, Omaha, Nebraska City, and Kansas City). Flow targets may be missed to conserve water if there is no commercial navigation in a given reach. Season support will end on Dec. 1 at the mouth of the Missouri River.

Winter Release Rate

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

Monthly Water Management Conference Calls

Water management calls include an update on the Missouri River mainstem reservoir system operations. The next call for 2024 will be held on Thursday, Sept. 5. The focus of this call will be winter release rates and fall release rates at Fort Peck. All calls are recorded in their entirety and are available to the public on our website at https://go.usa.gov/xARQv.

Fall Public Meetings

The Northwestern Division will host a series of public meetings the week of Oct. 28. The date and locations of the meetings are still being finalized.

Reservoir Forecasts:

• Gavins Point Dam
  • Average releases past month – 29,000 cfs
  • Current release rate – 33,500 cfs (as of Sept. 4)
  • Forecast release rate – 33,900 cfs (average September release)
  • End-of-August reservoir level – 1206.5 feet
  • Forecast end-of-September reservoir level – 1207.5 feet
  • Notes: Releases will be adjusted as necessary to meet all downstream navigation targets.
     
• Fort Randall Dam
  • Average releases past month – 27,900 cfs
  • End-of-August reservoir level – 1355.2 feet
  • Forecast end-of-September reservoir level – 1353.3 feet
  • Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point.
     
• Big Bend Dam
  • Average releases past month – 27,600 cfs
  • Forecast average release rate – 30,700 cfs
  • Forecast reservoir level – 1420.9 feet
     
• Oahe Dam
  • Average releases past month – 27,800 cfs
  • Forecast average release rate – 31,300 cfs
  • End-of-August reservoir level – 1604.4 feet (down 1.2 feet since Aug. 31)
  • Forecast end-of-September reservoir level – 1601.5 feet
     
• Garrison Dam
  • Average releases past month – 22,100 cfs
  • Current release rate – 22,000 cfs
  • Forecast average release rate – reduce to 14,000 cfs by mid-September
  • End-of-August reservoir level – 1840.1 feet (down 1.9 feet since Aug. 31)
  • Forecast end-of-September reservoir level – 1838.6 feet
     
• Fort Peck Dam
  • Average releases past month – 9,000 cfs
  • Current release rate – 9,000 cfs
  • Forecast average release rate – reduce to 4,000 cfs by mid-September
  • End-of-August reservoir level – 2227.5 feet (down 1.5 feet since Aug. 31)
  • Forecast end-of-September reservoir level – 2226.5 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 912 million kWh of electricity in August. Typical energy generation for August is 1,007 million kWh. The power plants are projected to generate 8.1 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 http://go.usa.gov/xVgWr.