The US Army Corps of Engineers’ says its latest 2023 calendar year runoff forecast for the upper Missouri River Basin (above Sioux City, Iowa) is showing improvement.
John Remus, chief of the Corps’ Missouri River Basin Water Management Division, says the 2023 calendar year runoff forecast above Sioux City is now 103% of average– or 26.4 million acre-feet. March 2023 runoff in the Missouri River Basin above Sioux City was 57% of average (1.7 MAF).
Forecast power generation from the six mainstem power plants 7.7 billion kWh, compared to the long-term average of 9.4 billion kWh.
Remus says the plains snowpack, which typically melts from mid-February into April, is hanging on longer this year and the plains snow on April 1 showed widespread areas of 4-8 inches of snow water equivalent across North Dakota and eastern South Dakota following a late March blizzard. Remus says the blizzard that occurred April 4-5 in the upper plains was not included in this forecast.
System storage is currently 46.8 MAF, or 9.3 MAF below the top of the carryover multiple use zone. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks.
Reservoir Forecasts:
Oahe Dam
- Average releases past month –17,200cfs
- Forecast average release rate – 10,300 cfs
- End-of-March reservoir level – 1594.8 feet
- Forecast end-of-April reservoir level – 1600.0 feet
Big Bend Dam
- Average releases past month – 17,600 cfs
- Forecast average release rate – 9,800 cfs
- Forecast reservoir level – 1421.0 feet
Remus says spring precipitation, including increased mountain snowpack and late season plains snow, has provided improved runoff conditions in the upper basin. He says slower plains snowmelt is preferred to improve soil conditions and to reduce the potential for flooding caused by rapid snowmelt from a spring rain event.
To view the detailed three-week release forecast for the mainstem dams, go to http://go.usa.gov/xVgWr.
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