Coralville Reservoir mitigates flood impact along Iowa River
As flood mitigation efforts continue across the corridor, there is slightly less concern for severe flooding in cities along the Iowa River.
Park rangers at Coralville Lake said the water height as of Wednesday night is near 690 feet above sea level, but is is expected to rise to just over 700 feet by mid-September.
However, this will still not be enough spill over the top of the reservoir and cause major flooding along the Iowa River.
If that happened, it would cause flood concerns for cities along river.
This happened back in 1993, and again in 2008, when water spilled over the Coralville Reservoir at more than 712 feet. This, in particular, led to some of the major flooding in Iowa City in 2008.
"They lost the ability to control the releases, and when that happens, then we're at the mercy of mother nature," said Witek Krajewski, Director of the Iowa Flood Center at the University of Iowa.
Reservoir experts said that will not necessarily be the case this year.
"So far we are operating as we were designed. We are doing exactly what were suppose to do, [and] we're able to hold the extra flood waters that are coming in," said Natural Resource Specialist Leah Deeds.
Deeds works with the U.S. Army Corps of Engineers. She said the reservoir operates under a water management plan that looks at rainfall and water shed levels to determine how much can leave Coralville Lake, and how much the dam will hold.
"We have a series of gates that help to control that, and those releases are based on whats coming in," said Deeds. "For example,there was 13,000 cubic feet of water per second coming into the river this morning, and there were only 6,000 cubic feet per second of water going out."
"It is using a small percentage of that flood storage right now, but there is a projection that the water level will go significantly up in the next ten days," said Krajewski.
Deeds said the reservoir is still pumping out six times less water than it did in 2008, which was about 39,500 cubic feet per second during the flood.
Still, levels will be monitored to ensure the dam continues to act as a buffer for cities in the corridor.
"And hope to reduce flooding downstream," said Deeds.
The Army Corps of Engineers said residents can look at current flood levels and predictions for Coralville Lake through rivergauges.com.