The U.S. Army Corps of Engineers announced higher than average runoff in the Missouri River Basin.

Runoff in the Missouri River Basin above Sioux City, Iowa, was 4.5 million acre feet during May, according to a news release from the Corps. That’s 136 percent of average. The 2016 calendar year runoff forecast is 25.3 million acre/feet, which is the historic average.

Water releases from the dam at Gavins Point are currently set at 21,500 cfs, were lowered in May to reduce flood risk along the lower river. Those releases will be gradually increased as the downstream stages decline.

“Conditions in much of the Missouri River Basin were wetter than average during May. In the upper basin, heavy rains accompanied by mountain snowmelt increased runoff into the reservoir system,” said Jody Farhat, chief of the Corps’ Missouri River Basin Water Management Division. Widespread rain in the lower basin also increased flows on many of the tributaries below the reservoir system, causing tributary and Missouri River levels to rise. “Rainfall events like these can lead to localized flooding downstream of the reservoir system,” said Farhat.

The total volume of water currently stored in the Missouri River Mainstem Reservoir System is 59.4 MAF, occupying 3.3 MAF of the 16.3 MAF flood control zone. “The reservoirs remain well positioned to capture additional runoff should further reductions in releases become necessary,” said Farhat. “We expect to provide good service to all of the authorized purposes.”

Based on the current runoff and reservoir regulation forecasts, full-service flow support is expected to be provided for the second half of the navigation season. The system storage on July 1 will determine the navigation flow support level for the second half of the season as well as the navigation season length.

You can read the entire release from the Corps of Engineers here.