Reservoir releases from Gavins Point Dam in South Dakota are being reduced from 28,000 cubic feet per second to 22,000 cfs in response to the heavy rain that fell over eastern Nebraska and western Iowa this weekend.
The rains increased flows on many of the tributary streams that enter the Missouri River below the main stem reservoir system, pushing some locations along the river to near flood stage. Releases from Gavins Point were reduced from 28,000 cfs to 26,000 cfs on Sunday, and then will be cut to 22,000 cfs on Monday.
"As part of our normal flood-risk-reduction efforts, we will reduce releases from Gavins Point Dam to help reduce stages on the lower river," said Jody Farhat, chief of the corps' Missouri River Water Management office in Omaha. "Similar release reductions will take place at several of the upstream reservoirs, including Fort Randall, Big Bend and Oahe."
The six corps' reservoirs on the Missouri River are operated as a system, so whenever release changes are made at one reservoir, those changes are reflected at some or all of the upstream projects, said Farhat.
The release reduction will cause the river at Sioux City to temporarily fall below the navigation target of 31,000 cfs, which is designed to provide a navigation channel 300 feet wide by 9 feet deep.