OMAHA, Neb. – The updated 2025 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. April runoff in the Missouri River Basin above Sioux City was 1.4 million acre-feet, 48% of average, according to the U.S. Army Corps of Engineers, Northwestern Division.

“Runoff into the reservoir system was below average for the month of April, and runoff was below average in all reaches,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division. “Drought or abnormally dry conditions are currently present in 75% of the basin, and conditions have worsened in the Fort Peck reach and parts of the Garrison reach in the last month. As a result, the runoff forecast was lowered by 1.9 MAF from last month.”

The 2025 calendar year runoff forecast above Sioux City is 20.0 MAF, 78% of average. The runoff forecast is based on current soil moisture conditions, mountain snowpack and long-term precipitation and temperature outlooks.