The updated 2025 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. February runoff in the Missouri River Basin above Sioux City was 1.0 million acre-feet, 91% of average.

“Runoff into the reservoir system was slightly below average for the month of February and conditions across most of the basin remain dry,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division.

“Mountain snowpack improved in February but is still below average. The plains snowpack, which was below average, has mostly melted. We are forecasting a below-average runoff year for the basin.”

The 2025 calendar year runoff forecast above Sioux City is 22.1 MAF, 86% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks.

The volume of water stored in the Missouri River Mainstem Reservoir System is currently 50.4 MAF, 5.7 MAF below the top of the carryover multiple use zone.

Releases from Gavins Point Dam are currently 12,000 cubic-feet-per-second and will remain low through mid-March to continue conserving water in the System, based on the guidance in the Missouri River Mainstem System Master Manual. “While the target winter release from Gavins Point Dam is 12,000 cfs, releases were set at 14,000 cfs for most of February due to extremely cold temperatures and ice conditions on the Missouri River below Gavins Point,” said Remus.

Basin and river conditions continue to be monitored, including plains and mountain snow accumulation, and System regulation will be adjusted based on the most up-to-date information.

Navigation:

Beginning in mid-March, releases from Gavins Point Dam will be adjusted to provide flow support for Missouri River navigation. Navigation flow support for the Missouri River is expected to be at 4,500 cfs below full-service for the first half of the 2025 season, which begins April 1 at the mouth of the river near St. Louis, Missouri. The actual service level will be based on the total volume of water stored within the System on March 15, in accordance with the guidelines in the Master Manual. Flow support for the second half of the navigation season, as well as navigation season length, will be based on the storage in the System on July 1.

Mountain and Plains Snowpack:

Mountain snowpack in the upper Missouri River Basin is accumulating at below average rates. The March 3 mountain snowpack in the Fort Peck reach was 89% of average, while the mountain snowpack in the Fort Peck to Garrison reach was 91% of average.  By March 1, about 79% of the total mountain snowfall has typically accumulated.  Mountain snow normally peaks near April 17. The mountain snowpack graphics can be viewed at: http://go.usa.gov/xARQC.  

Monthly Water Management Conference Calls for 2025:

The March 2025 monthly conference call will be held Thursday, March 6, to inform basin stakeholders of current weather and runoff forecasts and the planned operation of the reservoir system in the coming months. Presentation materials will be available via webinar. The call is intended for Congressional delegations; Tribes; state, county and local government officials; and the media. It will be recorded in its entirety and made available to the public on our website at https://go.usa.gov/xARQv.

Reservoir Forecasts:

• Gavins Point Dam
  • Average releases past month – 13,900 cfs
  • Current release rate – 12,000 cfs
  • Forecast release rate – 27,000 cfs
  • End-of-February reservoir level – 1206.8 feet
  • Forecast end-of-March reservoir level – 1206.0 feet
  • Notes: The Gavins Point release will be increased around March 15 to begin providing minimum service navigation flow support on the lower Missouri River.
     
• Fort Randall Dam
  • Average releases past month – 11,700 cfs
  • End-of-February reservoir level – 1350.2
  • Forecast end-of-March reservoir level – 1354.7 feet
  • Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point and to back up the Gavins Point release increases.  The reservoir will refill to near elevation 1355 by the end of March.
     
• Big Bend Dam
  • Average releases past month – 17,000 cfs
  • Forecast average release rate – 15,700 cfs
  • Forecast reservoir level – 1420.5 feet
     
• Oahe Dam
  • Average releases past month – 16,500 cfs
  • Forecast average release rate – 15,600 cfs
  • End-of-February reservoir level – 1598.8 feet
  • Forecast end-of-March reservoir level – 1598.9 feet
     
• Garrison Dam
  • Average releases past month – 23,500 cfs
  • Current release rate – 19,000 cfs
  • Forecast average release rate – 23,500 cfs
  • End-of-February reservoir level – 1830.4 feet
  • Forecast end-of-March reservoir level – 1830.2 feet
  • Notes – Releases are gradually being reduced to 17,000 cfs near the beginning of March.
     
• Fort Peck Dam
  • Average releases past month – 5,500 cfs
  • Current release rate – 5,500 cfs
  • Forecast average release rate – 5,500 cfs
  • End-of-February reservoir level – 2226.6 feet
  • Forecast end-of-March reservoir level – 2227.5 feet
  • Notes: Releases will remain at 5,500 cfs in March.

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 527 million kWh of electricity in February. Typical energy generation in February is 615 million kWh. Forecast generation for 2025 is 8.8 billion kWh 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.