YANKTON, S.D. -- Releases from Gavins Point Dam were increased for a second straight day Thursday to leave room in Lewis and Clark Lake for runoff from heavy rainfall and snowmelt upstream.
Gavins Point releases were increased to 50,000 cubic feet per second at the dam near Yankton, South Dakota. Releases will be increased to 60,0000 cfs later Thursday and into Friday.
Gavins Point releases were increased from 27,000 to 32,000 cfs at midnight Wednesday. A second increase from 32,000 to 37,000 cfs was made earlier that morning.
The corps said additional increases are likely to be made Friday, depending on the inflow.
The runoff in the drainage area between Fort Randall Dam and Gavins Point Dam is very high, and continues to increase, due to rapid plains snowmelt and heavy rain on frozen, wet soils in the Niobrara River basin, according to the corps. The area directly upstream Gavins Point continues to receive heavy rain.
"We know there are communities experiencing flooding, or nearing that condition, along the Missouri downstream of our dams,” said John Remus, chief of the Corps’ Missouri River Water Management Division in Omaha. “We are managing releases from Gavins Point as judiciously as we can in order to lessen the impact downstream.”
There's very little storage capacity behind Gavins Point, forcing the corps to release much of the water that enters the reservoir, according to Remus.
Releases from Fort Randall Dam, the Missouri main stem dam immediately upstream of Gavins Point, were shut off Wednesday and are expected to remain that way for the next several days.
Corps districts in Omaha and Kansas City have activated their emergency operation centers to support local communities and emergency managers with local flood responses.
Last week, the corps forecast runoff into the Missouri River basin above Sioux City for 2019 at 28.4 million acre-feet, 112 percent of average. The six reservoirs had their flood all capacity for flood water storage available, the corps said. The reservoir at Gavins Point is the smallest of the six.
During the months long Missouri River flooding in 2011, releases from Gavin the corps peaked at a record 160,200 cfs, breaking the previous mark of 70,000 cfs set in 1997.