Missouri River Basin Water Management U.S. Army Corps of Engineers, Northwestern Division

Test flows from Fort Peck Dam to comply with the 2018 Biological Opinion began Fri., April 26. The 2018 Biological Opinion requires the test under the Endangered Species Act for operation of the Missouri River Mainstem Reservoir System. These weekly virtual meetings during the flow test to update the public on test progress, monitoring and planned operations.

Test flows from Fort Peck Dam to comply with the 2018 Biological Opinion will begin Fri., April 26. The 2018 Biological Opinion requires the test under the Endangered Species Act for operation of the Missouri River Mainstem Reservoir System. The U.S. Army Corps of Engineers will host weekly virtual meetings during the flow test to update the public on test progress and planned operations.

The latest 2024 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa shows slight improvement. The 2024 calendar year runoff forecast above Sioux City is 17.5 million acre-feet (MAF), 68% of average. March runoff in the Missouri River Basin above Sioux City was 1.8 MAF, 59% of average. Even with the lower than average runoff forecast the hydrologic conditions are sufficient to conduct a flow test from Fort Peck Dam” said Remus. “The flow test is a requirement of the 2018 Biological Opinion and is meant to determine if there is a Fort Peck Dam water management scenario that could benefit the Pallid Sturgeon.

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.

January runoff in the Missouri River Basin above Sioux City was 0.4 million acre-feet, 56% of average. Runoff was well-below-average due to much-below-normal temperatures over the whole Missouri River Basin and below-normal precipitation over most of the upper basin. The 2024 calendar year runoff forecast above Sioux City is 18.8 MAF, 73% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks.

As the colder, winter temperatures enter the basin, USACE will closely monitor Missouri River ice conditions between the System reservoirs and downstream of Gavins Point Dam for potential ice jams that could impact river stages and water intakes. Runoff in the upper Missouri River Basin above Sioux City, Iowa, was 1.1 million acre-feet (MAF) during November, 107% of average. The 2023 calendar year runoff forecast is 29.9 MAF, 116% of average. Average annual runoff is 25.7 MAF.