Drought conditions in the upper Missouri River basin have expanded and intensified during the past month, reducing inflows to the Missouri River Mainstem Reservoir System. As a result, the U.S. Army Corps of Engineers, Missouri River Basin Water Management Division made a slight reduction in Gavins Point releases this week, from 33,000 cubic feet per second (cfs) to 32,000 cfs. Gavins Point releases were held steady at 33,000 cfs during June.
The total volume of water stored in the reservoir system is currently 61.8 MAF and is nearing its annual peak. With approximately 65 percent of the flood control storage remaining, the reservoirs remain well positioned to capture runoff from summer rainfall events in the upper basin. The vacant flood control storage will also allow for future reductions in Gavins Point releases in response to summer rainfall events in the lower basin if necessary.
The 2017 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 28.5 MAF, 113 percent of normal. Runoff above Sioux City, Iowa in June was 5.8 MAF, 106 percent of normal. The melt of the mountain snowpack is complete and inflows to the reservoirs are declining.