Corps: flooding risks along Missouri River remain high as water levels drop
August 24th, 2011 by Ric Hanson
While water levels on the flooded Missouri River are dropping, officials want safety awareness to remain high. This week’s rain prompted flash-flooding in southwest Iowa which led to building collapses, evacuations and daring rescues of trapped residents in the Council Bluffs area. Brigadier General John McMahon, of the U-S Army Corps of Engineers, says the public can’t let down its guard.
“I would caution everybody that we have to continue to be very vigilant in so far as the risks associated with this flooding,” General McMahon says. “The water is still high, it’s moving fast and there’s erosion and other effects. We’ve got to be vigilant in terms of how the levees, both the temporary and the permanent ones, are performing. We’re not out of the woods yet.” Releases of water from upriver reservoirs, like Gavins Point Dam near Yankton, South Dakota, are being cut back daily. That process started last Friday and will continue through month’s end. Still, South Dakota Governor Dennis Daugaard (DO-guard) warns that significant danger lurks as the release levels drop. He says the next week or so will be crucial.
“If there is going to be a catastrophic failure of any levee, it probably could occur during that time,” Governor Daugaard says. “We want to urge our citizens not to become complacent, which is easy to do, because they see the end in sight, the light at the end of the tunnel.” Daugaard says residents in all states along the Missouri River need to remain at the ready for potential risks.
“We really have to be careful as the subjacent weight of the water draws away, the super-saturated soils that make up those levees could slough,” he says. “It’s very important that we have vigilance on those levees during this next ten-day period and not allow our citizens to become complacent.” Iowa’s Governor Branstad met in Omaha last week with his counterparts from a half-dozen other Missouri River states to discuss avenues to prevent a repeat of the summer-long flooding. While the water has been high more than two months already, Missouri Governor Jay Nixon says it could be October before the flooded waterway returns to normal.
“When you have a system this charged, it’s important for the public to know they always need to be careful,” Governor Nixon says. “We’ve lost a National Guardsman coming back from duty, we’ve lost a trooper that we’re still searching for. It’s a very dangerous river. Everybody out there should be well aware of the danger and the power of this much water moving this quickly. No, this is not over, not until it gets back inside its banks and it’s a long way from getting there.”
Releases from Gavins Point topped out around 160-thousand cubic feet per second (CFS) — or around one-point-one million gallons per second. By month’s end, the releases should be down to 90-thousand C-F-S. Those reductions will halt on September 1st, allowing the Corps to inspect the system’s levees and dams.