Army Corps of Engineers reduce outflow of Coralville Lake
Lake level expected to increase, lessen flooding impact to south
CORALVILLE — The outflow of the Coralville Lake was temporarily reduced by the Army Corps of Engineers to help lessen flooding further south.
The flow of water from the reservoir was reduced from 6,000 cubic feet per second or CFS to 1,000 CFS on Tuesday, according to a Johnson County Emergency Management news release. The Army Corps of Engineers expects to return outflow to normal on Monday.
Although Johnson County remained largely unaffected by recent flood in Eastern Iowa, this reduction in outflow should help reduce the impact downstream in Louisa County — where the Iowa and Cedar Rivers meet. In Columbus Junction, the water is expected to crest at 26.6 feet, more than 7.5 feet higher than flood stage, Thursday night into Friday morning.
The reduced outflow of the lake coupled with the intake from northern communities is expected to increase the Coralville Lake’s level to 701 feet overnight Thursday Oct. 7 into Friday Oct. 8. The Coralville spillway is not breeched until water levels reach 712 feet — only happening in 2008 and 1993.
“At this point we continue to monitor the situation and provide any assistance requested from the affected communities. We have 350,000 sandbags on hand, as well as HESCO barriers available for flood protection if conditions warrant,” said Dave Wilson, the county’s emergency management coordinator, in the release.
Residents can track the water level on the Iowa Flood Center’s database.
For all of The Gazette's Flood 2016 coverage, please visit our flood coverage center.