Water levels in the Coralville Lake rose slightly over the past 24 hours, but the projected crest continues to decline, officials said Saturday.
The Army Corps of Engineers’ projection continues two days of good news for residents downstream despite rain within the watershed on Saturday.
Current levels show the lake at 706.1 feet, up about a foot from yesterday. Barring major rain, the lake should crest at 708.4 feet on July 11 and slowly decrease. That would put the crest about four feet below topping the spillway.
Earlier this week, levels were expected to exceed 712 going over the lake’s spillway, which was erected to prevent flooding. Water flowed over the spillway in 1993 and 2008 causing significant flooding.
The National Weather Service predicts one-half inch to 2 inches of rainfall over the next five days, which Terrence Neuzil, Johnson County Emergency Management spokesman said would be manageable.
Officials remain concerned about the worst case scenario prediction which calls for 4.3 inches of rain in coming days just south of the Iowa River basin. Officials haven’t complete the calculations to determine what happens if that rain fell within the watershed, Neuzil said.
Reservoir outflows will continue at 18,000 cubic feet per second, but could be reduced to 12,000 cubic feet per second by July 17. Lower outflow means river levels would begin to stabilize avoiding additional flooding to homes and businesses located downstream.
IOWA RIVER FLOOD SIMULATOR: To view a Iowa River flood impact simulator, click here.
CURRENT ROAD CLOSURES: To view a current list of flood-related road closures, click here.