Drought Pattern Continues In Missouri Basin
September precipitation was once again below average in the Missouri River Basin, the Corps of Engineers reports. September runoff in the basin above Sioux City, Iowa, was 0.6 million acre-feet (maf.), 47 percent of the long-term average.
Soil conditions in the upper basin continue to be very dry. According to the Drought Mitigation Center, more than 90 percent of the Missouri River basin is currently experiencing some form of abnormally dry conditions or drought, which is almost a 20 percent increase from the end of August.
“Runoff in the upper Missouri River Basin was below average during the month of September and is expected to remain low throughout the rest of 2022,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division.
“Releases from Gavins Point Dam will continue to be set to maintain a service level 500 cubic feet per second above the minimum service level,” Remus added.
The 2022 calendar year runoff forecast for the upper basin, updated on October 1, is 19.5 maf., 76 percent of average and 0.7 maf. lower than last month’s annual runoff forecast. Average annual runoff for the upper basin is 25.7 maf.
Total system storage as of October 5 was 48.5 maf., which is 7.6 maf. below the base of the flood control zone.
Gavins Point Dam releases will be set to provide navigation flow support at a level 500 cfs. above minimum service at all four target locations (Sioux City, Omaha, Nebraska City, and Kansas City). Season support will end on November 28 at the mouth of the Missouri River at St. Louis, Mo.
In anticipation of the low winter releases, a letter was sent in early July to all water users below Gavins Point Dam making them aware of the planned releases and encouraging them to assess the risk to their facilities. The volume of water in the Missouri River downstream of the system will be adequate for water supply needs, the Corps said. However, the Corps cannot guarantee access to the water; access to the water is the responsibility of the individual intake owner/operators, the Corps said.v