Water releases at Gavins Point Dam upstream on the Missouri River have dropped dramatically, but will hold steady for a while.
The US Army Corps of Engineers has lowered releases at Gavins Point from 160,000 cubic feet per second to 90,000. The Corps is holding releases at Gavins Pont steady at 90,000 cfs through September 14th. Plans call for the releases to drop steadily thereafter, lowering eventually to 40,000.
The Chief of the Engineering Division at the Corps’ Omaha office, John Bertino, says the pause gives the Corps time to inspect infrastructure, such as the levees, and assess any damage done by the summer-long flood. Bertino says crews will be checking sophisticated equipment located up and down the river to determine how the levees have held up under the months-long pressure.
“Our concern is we don’t want to lower the water so quickly that we cause excess uplift,” Bertino says. “So, we’ll be using those instruments to determine whether or not that uplift pressure, that water pressure, is dissipating quick enough.”
The Corps also is concerned about how the levees might react should the water releases drop too quickly. A sudden drop could pull floodwaters off the levees too quickly, triggering sloughing. The Corps is hoping that the steady, gradual lowering of releases will avoid that problem. It also is counting on a more natural receding of Missouri River floodwaters which could allow land covered by water for months to dry prior to resuming a drop in water releases.
Bertino forecasts the Missouri River to return to its banks in the Omaha area around September 20th, closer to early October for downstream Nebraska cities.
The Corps of Engineers has lowered releases at all six of the upstream dams: 25,000 cfs at Ft. Peck, 60,000 cfs at Garrison, 80,000 at Oahe, 80,000 at Big Bend, 88,000 at Ft. Randall and 90,000 at Gavins Point.