A warm February led to increased snowmelt and runoff in the Missouri River Basin above Sioux City, Iowa. February runoff was 1.8 million acre-feet, 161% of average with above average runoff in every reach except Sioux City, which was near average. However, the updated 2024 calendar year runoff forecast for the basin continues to be below average.   

“Despite the increased runoff in the month of February, and improved soil moisture conditions, we expect 2024 runoff to remain below average,” said John Remus, chief of the U.S. Army Corps of Engineers’, Missouri River Basin Water Management Division.  “The much warmer-than-normal temperatures led to an early melt of the lower-than-average plains snow.  In addition, mountain snowpack is lower than average, resulting in the low annual runoff forecast.” Soil moisture conditions are near or above normal across most the basin with below-normal soil moisture conditions spanning eastern portions of the basin.

The 2024 calendar year runoff forecast above Sioux City is 17.0 MAF, 66% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks. 

System storage is currently 53.9 MAF, 2.2 MAF below the top of the carryover multiple use zone. 

“The System will continue to serve all Congressionally authorized purposes during 2024,” 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 500 cubic feet-per-second 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 below average rates. The March 3, mountain snowpack in the Fort Peck reach was 73% of average, while the mountain snowpack in the Fort Peck to Garrison reach was 78% of average.  By March 1, about 80% 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.  

The plains snowpack, which typically melts from mid-February into April, is almost nonexistent in the Basin.  Trace to 1” of snow water equivalent is modeled in eastern North Dakota.

Monthly Water Management Conference Calls for 2024:

The March 2024 monthly conference call will be held Thursday, March 7, 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.

Spring Public Meetings:

The Northwestern Division, Missouri River Basin Water Management Division will host a series of public meetings the week of March 25.  Dates and locations are listed below.  Additional information, with specific times and venues, will be provided in a future news release and will also be posted to the website at:  https://www.nwd.usace.army.mil/MRWM/Public-Meetings/.

• Tuesday, March 26 – Fort Yates, North Dakota
• Wednesday, March 27 – Fort Pierre, South Dakota
• Thursday, March 28 – Poplar, Montana

Reservoir Forecasts:

• Gavins Point Dam
  • Average releases past month – 13,000 cfs
  • Current release rate – 13,000 cfs
  • Forecast release rate – 20,600 cfs
  • End-of-February reservoir level – 1206.6 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 – 7,100 cfs
  • End-of-February reservoir level – 1352.1
  • Forecast end-of-March reservoir level – 1354.8 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 – 12,400 cfs
  • Forecast average release rate – 20,600 cfs
  • Forecast reservoir level – 1421.0 feet
     
• Oahe Dam
  • Average releases past month – 10,800 cfs
  • Forecast average release rate – 21,100 cfs
  • End-of-February reservoir level – 1603.6 feet
  • Forecast end-of-March reservoir level – 1603.3 feet
     
• Garrison Dam
  • Average releases past month – 24,900 cfs
  • Current release rate – 16,000 cfs
  • Forecast average release rate – 16,000 cfs
  • End-of-February reservoir level – 1835.1 feet
  • Forecast end-of-March reservoir level – 1834.6 feet
  • Notes – Releases were gradually reduced from 25,000 cfs to 16,000 cfs near the beginning of March.
     
• Fort Peck Dam
  • Average releases past month – 5,400 cfs
  • Current release rate – 5,000 cfs
  • Forecast average release rate – 5,000 cfs
  • End-of-February reservoir level – 2230.4 feet
  • Forecast end-of-March reservoir level – 2230.9 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 467 million kWh of electricity in February. Typical energy generation for February is 618 million kWh. Forecast generation for 2024 is 8.3 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.