Even though the drought has dropped levels in Missouri River reservoirs drastically, last year’s flood damage is still being repaired at key points along the waterway.
Just upriver, restoration is underway at Gavins Point Dam near Yankton, South Dakota.
Dave Becker, the dam’s operations manager, says bank restoration work is being done just downstream from the dam on the north shore.
“We lost about 12 foot of river bed there so we lost the foundation for that riprap,” Becker says.
“That riprap work is going on and that’ll probably be going on for three or four more months.” The water releases last summer topped 160,000 cubic feet per second and caused damage along and under the concrete slab just in front of the spillway gates. Becker says repairs are planned for that area, too.
“We are going to have to do some work on the spillway slab,” Becker says. “They have to do more testing on that. It’ll need to wait until our spillway flows stop, about Thanksgiving or so.”
Becker says contractors will drill through the massive slab, working to fill some voids that developed in the gravel bed under the concrete as the floodwaters churned.
“They are going to drill through the slab, try and fill the two largest voids and they’ll drill more test holes through the slab to check what the conditions are below,” he says. Much of the work will extend into next spring.
By Jerry Oster, WNAX, Yankton