The updated 2022 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. 

“The runoff in February was less than predicted, and we expect the lower-than-average runoff to continue in the coming months,” said John Remus, chief of the U.S. Army Corps of Engineers’, Missouri River Basin Water Management Division.

“The snow accumulation in both the plains and the mountains continues to be below average, and the soil moisture remains very low compared to normal. This resulted in us lowering our anticipated runoff for the 2022 water year,” he added.

The 2022 calendar year runoff forecast above Sioux City, Iowa, has dropped from 21.7 million acre feet last month to 20.4 MAF on March 1, a reduction of 1.3 MAF. If realized, this forecast would be 79% of normal.

Runoff forecasts incorporate several factors including end-of-February soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks. Based on these factors, runoff is expected to be well below normal for all reaches except from Gavins Point Dam to Sioux City.

February runoff in the Missouri River Basin above Sioux City was 0.9 million acre-feet, 78% of average. Runoff was below-average due to lack of snow accumulation coupled with the drier-than-normal soil conditions in the upper Basin. Drought conditions are about the same as they were at the beginning of February, with 89% of the Basin experiencing abnormally dry or drought conditions. 

System storage is currently 48.1 MAF, 8.0 MAF below the base of the annual flood control zone.  The System will continue to serve all Congressionally authorized purposes during 2022, including flood control, navigation, and water supply.

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 minimum levels for the first half of the 2022 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 Feb. 27, mountain snowpack in the Fort Peck reach was 80% of average, while the mountain snowpack in the Fort Peck to Garrison reach was 82% of average. By March 1, about 80% of the total mountain snowpack has typically accumulated. Mountain snowpack normally peaks near April 15. The mountain snowpack graphics can be viewed at: https://go.usa.gov/xt7UH. Currently, plains snowpack in the upper Missouri River Basin is very light to non-existent.

Monthly Water Management Conference Calls for 2022:

The March 2022 monthly conference call will be held Thursday, March 3, 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 the Defense Video and Imagery Distribution System at https://go.usa.gov/xt7Uz.

Spring Public Meetings:

The spring public meetings will be held the week of April 11. The purpose of these meetings is to update the region on current hydrologic conditions and the planned operation of the mainstem reservoir system during the coming months. More information will be provided when it is available.

Reservoir Forecasts:

• Gavins Point Dam
  • Average releases past month – 13,200 cfs
  • Current release rate – 12,000 cfs
  • Forecast release rate – 17,200 cfs
  • End-of-February reservoir level – 1204.8 feet
  • Forecast end-of-March reservoir level – 1206.0 feet
  • Notes: The Gavins Point release will be increased around March 18 to begin providing minimum-service navigation flow support on the lower Missouri River.
     
• Fort Randall Dam
  • Average releases past month – 9,700 cfs
  • End-of-February reservoir level – 1249.7 feet (up 4.1 feet from January)
  • Forecast end-of-March reservoir level – 1355.0 feet
  • Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point and to back up Gavins Point releases. The reservoir will refill to elevation 1355.0 ft msl by the end of March.
     
• Big Bend Dam
  • Average releases past month – 14,200 cfs
  • Forecast average release rate – 20,100 cfs
  • Forecast reservoir level – 1420.6 feet
     
• Oahe Dam
  • Average releases past month – 14,100 cfs
  • Forecast average release rate – 19,900 cfs
  • End-of-February reservoir level – 1597.1 feet (down 0.2 feet from January)
  • Forecast end-of-March reservoir level – 1597.5 feet
     
• Garrison Dam
  • Average releases past month – 15,600 cfs
  • Current release rate – 14,500 cfs
  • Forecast average release rate – 14,500 cfs
  • End-of-February reservoir level – 1827.7 feet
  • Forecast end-of-February reservoir level – 1828.2 feet
     
• Fort Peck Dam
  • Average releases past month – 9,100 cfs
  • Current release rate – 7,500 cfs
  • Forecast average release rate – 4,500 cfs
  • End-of-February reservoir level – 2222.5 feet
  • Forecast end-of-March reservoir level – 2222.8 feet
  • Notes: Releases will be lowered to 4,500 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 448 million kWh of electricity in February. Typical energy generation for February is 624 million kWh.  The power plants are expected to generate 7.4 billion kWh 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.usa.gov/xt7PC.

The Missouri Basin Web App provides links to these reports and others that are updated more frequently. https://go.usa.gov/xt7Pb.