The U.S. Army Corps of Engineers Missouri River Basin Water Management Division reports April runoff in the Missouri River Basin above Sioux City, Iowa, was 1.5 million acre feet (MAF), 52 percent of normal. The 2015 runoff forecast in the Missouri River Basin above Sioux City, Iowa, has decreased 1 MAF from last month to 19.3 MAF, 76 percent of normal. Average annual runoff is 25.2 MAF.