Minor Improvement Reported In Missouri River Runoff Outlook
The Corps of Engineers reported only slight improvement in the runoff forecast for the upper Missouri River Basin.
“The overall lack of snowpack in both the plains and the mountains has led to a below average runoff forecast for the Missouri River Basin,” said John Remus, chief of the Corps’ Missouri River Basin Water Management Division, in the division’s monthly report April 8.
“The soil is dry across much of the basin, with over 60 percent of the basin experiencing drought.”
The 2024 calendar year runoff forecast above Sioux City has been updated to 17.5 million acre-feet (maf.), 68 percent of average. The runoff forecast is based on current soil moisture conditions, mountain snowpack and long-term precipitation and temperature outlooks.
March runoff in the region was 1.8 maf., 59 percent of average.
“While the forecast remains below average, the basin has shown some improvement in runoff conditions since the March forecast,” Remus said. A month ago, the calendar-year forecast was for 17.0 maf. “Given reach runoff and basin conditions, we expect runoff in April to remain below normal for all reaches, but this will depend on precipitation and temperatures.”
Navigation
Beginning in mid-March, releases from Gavins Point Dam were adjusted to provide flow support for Missouri River navigation. Navigation flow support for the Missouri River is at 500 cfs. below full service for the first half of the 2024 season, which began April 1 at the mouth of the river near St. Louis, Mo. The service level was based on the total volume of water stored within the system on March 15, which was 54.1 maf.
Flow support for the second half of the navigation season, as well as navigation season length, will be based on system storage on July 1.
Fort Peck Flow Test
The Corps will perform a flow test at Fort Peck Dam in Montana beginning April 26. The test releases will be used to assess the potential benefits of alternative management scenarios for the endangered pallid sturgeon and is a requirement of the 2018 Biological Opinion.
The test includes two higher Fort Peck release periods, in late April and June, with target flows at Wolf Point, Mont. During the flow test, a number of monitoring activities will be conducted, including fish monitoring, lidar and aerial photography, physical surveys, cultural resource surveys and water quality sampling.
The flow test has been extensively coordinated with local stakeholders and was discussed in depth at a public meeting held in Poplar, Mont., on March 28.
The test will not affect river stages below Gavins Point Dam, which is the head of navigation on the river, the Corps said.
Public Meetings
The Missouri River Basin Water Management Division held a series of public meetings in the upper basin the week of March 25. Meetings for the lower basin are scheduled to be held April 16 in Smithville, Mo., and Bellevue, Neb. The Smithville meeting will begin at 11 a.m. at the Jerry Litton Visitor Center, 16311 DD Hwy., Smithville, Mo. 64089; the Bellevue meeting will begin at 4 p.m. at the Hitchcock Humanities Building, Bellevue University, 1040 Bruin Blvd., Bellevue, Neb. 68005.
