May was the second-wettest month for northern Wyoming, Montana, and North Dakota since 1889.
To relieve pressure on the river, the Corps plans to release 150,000 cubic feet per second of water at the Oahe Dam above Pierre, S.D., on Tuesday. The other dams will be opened in succession, remaining open through mid-August.
Kevin Grode, a Missouri Basin reservoir regulation team leader with the Corps, says the amount of water released may increase, depending on the changing climate.
“We are going to be testing the system,” he stresses, “because we’ll be releasing more water than has ever been released before.”
Local officials in some states are criticizing the Corps for not opening the dams earlier, which Mr. Grode challenges. “Conditions in the basin were not as extreme as they are now,” he says. “We did not see a great need.”
Water is already surging at all six of the dams along the river, breaking records at each one. According to Grode, runoff waters are highest at Gavins Point, located near Yankton, S.D. The flow there reached 10.5 million acre-feet, breaking a previous record of 7.2 acre-feet, set in 1995.
While Grode says the dams are all “very safe,” the levee system is more vulnerable – and will likely be stressed throughout the year, he warns. Tributary systems that feed into the Missouri River are also expected to flood.