September runoff in the Missouri River Basin above Sioux City, Iowa, was 1.0 million acre feet, 91 percent of average, according to the U.S. Army Corps of Engineers. This marks the fourth consecutive month with below average runoff in the upper basin. The 2016 calendar year runoff forecast is 22.7 MAF, which is 90 percent of the historic average. The total volume of water stored in the Mainstem Reservoir System on October 1 was 57.4 MAF, occupying 1.3 MAF of the 16.3 MAF combined flood control storage zones. System storage declined 0.7 MAF during September. Water that was captured in the reservoirs during the spring and summer is being released during the drier months to serve navigation, irrigation and other authorized purposes.