Emergency management officials in Des Moines say the immediate threat of a levee breach just north of downtown Des Moines appears to have passed, but the danger of flooding is not over. The Des Moines River running through the capitol city crested lower than predicted earlier this morning .
Officials say some seepage that began Thursday has stabilized. Corps engineer Tom Heinold says the Corps is watching the levee that protects the Birdland Neighborhood in Des Moines as the water recedes. “There’s always a risk. We try to reduce it by taking some advance measures, which the city has done,” Heinold says. “So we’re not at high risk but, yes, there’s still a risk.”
The Birdland Neighborhood in Des Moines flooded in 1993 and 2008. Heinold says the danger of levy failure hasn’t yet passed. “It may seem counterintuitive but the more dangerous time for a levee is not when the water is coming up on it, but rather when it is going back down,” Heinold says. “The saturated levee is trying to loose it’s water and, as the river drops, that hydraulic pressure is no longer there to hold the material up on the levee.”
Heinold says constant monitoring of levies in the Des Moines area will continue until the Saylorville Reservoir north of Des Moines drops about 50 feet — sometime late this summer, at the earliest given all the rain that’s fallen in the region. The Lake Red Rock Reservoir near Knoxville is downstream.
According to the Army Corps of Engineers, that reservoir is a 93.5% capacity for “flood storage.” The level of the federal reservoir called Coralville Lake near Iowa City is also rising, too, due to increased levels in the Iowa River. But the Army Corps of Engineers reported yesterday that Coralville Lake is at 56% capacity.
Photo courtesy of Polk County