The updated 2024 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average.   

January runoff in the Missouri River Basin above Sioux City was 0.4 million acre-feet, 56% of average. Runoff was well-below-average due to much-below-normal temperatures over the whole Missouri River Basin and below-normal precipitation over most of the upper basin.

“The runoff into the reservoir system was well-below average for the month of January,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division. 

“This fact in conjunction with the below-average plains and mountain snowpack indicates a below-normal runoff year for the basin.”

The 2024 calendar year runoff forecast above Sioux City is 18.8 MAF, 73% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks.

At the start of the 2024 runoff season, which typically begins around March 1, the total volume of water stored in the Missouri River Mainstem Reservoir System is expected to be 52.7 MAF, 3.4 MAF below the top of the carryover multiple use zone.

To conserve water in the System, releases from Gavins Point Dam are scheduled to be 13,000 cfs this winter while still serving the needs of the municipal, industrial and powerplant water intakes along the lower river. 

“While the target winter release from Gavins Point Dam is 13,000 cfs, releases were increased to 15,000 cfs in mid-January to mitigate some of the effects of the much colder temperatures across the lower basin,” said Remus.  Releases were reduced to 13,000 cfs at the end of the month and will be held at that rate through February.

“With weather conditions and river stages forecast to be more seasonal over the next few weeks, System releases are returning to the target winter rates,” 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:
Navigation flow support for the Missouri River is forecast to be at 1,500 cfs below full-service for the first half of the 2024 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 well-below average rates. The Feb. 1, mountain snowpack in the Fort Peck reach was 51% of average, while the mountain snowpack in the Fort Peck to Garrison reach was 64% of average.  By Feb. 1, about 60% 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.  

Fort Peck Flow Test:
Test releases from Fort Peck that would assess the potential benefits of alternative management scenarios for the pallid sturgeon are currently planned to be implemented in 2024.  The test includes two higher Fort Peck release periods, in late April and June, with target flows at Wolf Point, Montana.  The Fort Peck releases will be adjusted depending on the runoff and reach conditions downstream of Fort Peck during this period. The test will likely require spillway releases from Fort Peck.  The test releases will not affect the regulation below the reservoir system.

Monthly Water Management Conference Calls for 2024:
The February 2024 monthly conference call will be held Thursday, Feb. 8, 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 – 14,400 cfs
  • Current release rate – 13,000 cfs
  • Forecast release rate – 13,000 cfs
  • End-of-January reservoir level – 1207.4 feet
  • Forecast end-of-February reservoir level – 1205.9 feet
  • Notes: The winter release rate will be at least 13,000 cfs and may be adjusted to lessen the impacts of winter ice formation.
     
• Fort Randall Dam
  • Average releases past month – 12,100 cfs
  • End-of-January reservoir level – 1345.2
  • Forecast end-of-February reservoir level – 1349.7 feet
  • Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point.  The reservoir was drawn down to 1337.5 feet near the end of November 2023 to provide space for winter hydropower generation at Oahe and Big Bend. The reservoir will refill to the base of the flood control pool by the end of February.
     
• Big Bend Dam
  • Average releases past month – 16,200 cfs
  • Forecast average release rate – 14,700 cfs
  • Forecast reservoir level – 1420.6 feet
     
• Oahe Dam
  • Average releases past month – 16,300 cfs
  • Forecast average release rate – 14,500 cfs
  • End-of-January reservoir level – 1600.0 feet
  • Forecast end-of-February reservoir level – 1602.1 feet
     
• Garrison Dam
  • Average releases past month – 18,300 cfs
  • Current release rate – 24,000 cfs
  • Forecast average release rate – 24,900 cfs
  • End-of-January reservoir level – 1836.9 feet
  • Forecast end-of-February reservoir level – 1834.4 feet
  • Notes – Releases were set at 16,000 cfs prior to the river freeze-in at Bismarck, North Dakota. Releases are gradually being increased to 25,000 cfs as downstream conditions permit to benefit winter hydropower generation and to better balance storage in the upper three reservoirs.
     
• Fort Peck Dam
  • Average releases past month – 5,600 cfs
  • Current release rate – 5,000 cfs
  • Forecast average release rate – 5,000 cfs
  • End-of-January reservoir level – 2229.4 feet
  • Forecast end-of-February reservoir level – 2229.7 feet
  • Notes: Releases will remain at 5,000 cfs in February.

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 540 million kWh of electricity in January. Typical energy generation for January is 707 million kWh. Forecast generation for 2024 is 8.6 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.