Missouri River Levels Below Average

The latest weekly report on water levels in the upper Missouri River, posted July 21 by the Northwest District of the Corps of Engineers, didn’t change the outlook substantially. After evaluating Missouri River system storage on July 1, the Corps of Engineers said it was reducing flow support to minimum service. The official navigation support season was shortened by 16 days, cutting off early on November 15 rather than December 1.

Lower Missouri River lower reaches have experienced periods of flash flooding and localized emergencies. System storage reported on July 21 was 49.1 million acre-feet (MAF), 0.1 MAF less than the previous week.

The Corps forecast 2026 calendar year runoff at just 15.5 million acre-feet, or 60 percent of the historical average. Mountain snowpack peaked on March 16 at 77 percent of normal and 79 percent of normal in the Fort Peck and Garrison reaches, respectively. As of June 22, effectively no snowpack remained in either reach. More than 77 percent of the basin is currently experiencing abnormally dry or drought conditions, with 14 percent classified as extreme or exceptional drought.

The Gavins Point reservoir is currently releasing 24,000 cubic feet per second (cfs). Releases will be adjusted as necessary to support authorized purposes. The complete release schedule for Gavins Point is shown in the daily forecast at www.nwd-mr.usace.army.mil/rcc/reports/pdf/GRFT.pdf.

The Climate Prediction Center 6-10 Day outlook on July 21 showed that basin temperatures would likely remain above normal with the chance for precipitation to remain normal, or slightly below normal.

The Fort Peck reservoir stood at 9.8 feet below the base of the Annual Flood Control Zone. The Garrison reservoir stood at 9.5 feet below the zone, and the Oahe reservoir at 10.4 feet below. The system as a whole stood at 7.2 MAF below the base of the Annual Flood Control Zone.

Missouri River water management may be tracked at https://www.nwd.usace.army.mil/mrwm/mrwm-news.