OMAHA, NE – August runoff in the Missouri River Basin above Sioux City, Iowa was 1.0 million acre-feet (MAF), 73% of average. Runoff was well below normal in the Fort Peck and Garrison reaches due to dry soil moisture conditions and areas of below-normal precipitation. Runoff was above normal for the Oahe, Fort Randall, and Gavins Point reaches, and near normal in the Sioux City reach, mostly due to above-normal precipitation during parts of August.
“August runoff was higher than forecast in the lower reaches of the upper Missouri River Basin above Sioux City due to late summer rainfall. In addition, rainfall below Gavins Point allowed the System reservoirs to maintain lower release rates while meeting the reduced navigation flow...
The U.S. Drought Monitor indicates that over 83% of the Missouri River Basin is abnormally dry or in drought conditions. Drought conditions are expected to improve in Colorado, southern Wyoming, and western Nebraska and Kansas by the end of November as El Nino conditions strengthen. September runoff in the upper Basin is forecast to be well-below average, especially in the Fort Peck and Garrison reaches. The updated 2026 calendar year forecast for the upper Basin is 15.4 MAF, 60% of average. Average annual runoff for the upper Basin is 25.7 MAF.
At McNary Lock and Dam, Unit 14 is first in a program to replace 75-year-old turbines across all 14 main generating units. The first installation uses a five-bladed adjustable runner designed for McNary, with project objectives that include improved reliability, turbine efficiency and fish passage. The work reflects continued investment in critical Columbia River infrastructure and the teams responsible for delivering it safely.
