The updated 2022 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average.
John Remus is the chief of the US Army Corps of Engineers’ Missouri River Basin Water Management Division. He says 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.
The 2022 calendar year runoff forecast above Sioux City, Iowa, has dropped from 21.7 million acre feet last month (Feb. 2022) to 20.4 MAF on March 1, 2022, a reduction of 1.3 MAF. If realized, this forecast would be 79% of normal. February runoff in the Missouri River Basin above Sioux City was 0.9 million acre-feet, 78% of average.
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.
System storage is currently 48.1 MAF, 8.0 MAF below the base of the annual flood control zone. 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.
Incidentally, the Corps will hold its annual spring public meetings the week of April 11, 2022.
Oahe Dam Reservoir forecast:
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 Jan.)
Forecast end-of-March reservoir level – 1597.5 feet
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