OMAHA, Neb. -- “August runoff was above average in the lower reaches of the upper Missouri River Basin above Sioux City due to timely rainfall. This allowed the System reservoirs to maintain lower release rates while meeting the reduced navigation flow targets at all downstream locations,” 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 continue to be well-below average due to long-term precipitation deficits and the below-normal mountain snowpack in the Missouri Basin. Reservoir levels at Fort Peck and Garrison dropped about 1.6 feet in August, and System storage will continue to decline this fall,” Remus added.
While more than 59% of the Missouri Basin is not experiencing drought conditions; in the western Basin, drought is expected to persist and expand to new regions of the Basin through November.
August runoff was 1.5 million acre-feet, 109% of average above Sioux City with most of the runoff entering the System below Garrison Dam. September runoff in the upper Basin is forecast to be well below average, especially in the Fort Peck and Garrison reaches. The updated 2025 calendar year forecast for the upper Basin is 19.1 MAF, 74% of average. Average annual runoff for the upper Basin is 25.7 MAF.
As of Sept. 1, the total volume of water stored in the System was 51.0 MAF, down 0.7 MAF during August. Updated reservoir studies indicate System storage is expected to be 48.0 MAF the start of the 2026 runoff season, approximately 8.1 MAF below the base of flood control zone.
Fort Peck releases will be reduced from 9,000 cfs to the fall rate of 4,000 cfs at the end of September. Garrison releases were reduced to 19,000 cfs in mid-August and will be reduced to 14,000 cfs on Sept. 16.
Navigation
Gavins Point Dam releases are being set to provide navigation flow support at a level 4,500 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 no commercial navigation traffic is within a given reach. Season support will end 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 September 1 System storage. Per the September 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.
Fall Public Meetings
The Northwestern Division will host a series of public meetings during the last week of October and first week of November. The dates and locations of the meetings are still being finalized.
Reservoir Forecasts:
- Gavins Point Dam
- Average releases past month – 22,300 cfs
- Current release rate – 23,500 cfs (as of September 5)
- Forecast release rate – 24,400 cfs (average September release)
- End-of-August reservoir level – 1207.1 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 – 20,000 cfs
- End-of-August reservoir level – 1355.3 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 – 19,600 cfs
- Forecast average release rate – 20,200 cfs
- Forecast reservoir level – 1420.7 feet
- Oahe Dam
- Average releases past month – 20,400 cfs
- Forecast average release rate – 20,300 cfs
- End-of-August reservoir level – 1599.5 feet (up 0.2 feet since July 31)
- Forecast end-of-September reservoir level – 1598.7 feet
- Garrison Dam
- Average releases past month – 20,300 cfs
- Current release rate – 19,000 cfs
- Forecast average release rate – reduce to 14,000 cfs by mid-September
- End-of-August reservoir level – 1832.7 feet (down 1.6 feet since July 31)
- Forecast end-of-September reservoir level – 1831.8 feet
- Fort Peck Dam
- Average releases past month – 8,800 cfs
- Current release rate – 9,000 cfs
- Forecast average release rate –9,000 cfs through the end of September
- End-of-August reservoir level – 2224.4 feet (down 1.6 feet since July 31)
- Forecast end-of-September reservoir level – 2222.6 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 713 million kWh of electricity in August. Typical energy generation for August is 1,005 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.
We've created additional URLs to track Missouri forecast data at:
https://go.mil/mr-webapp (Missouri River Web App)
https://go.mil/mr-snap (Missouri River Snap Shot)
https://go.mil/mr-wkupdate (Missouri River Weekly Update)
Go to these links and save them on your Smart Phone's home screen.