JOHNSON COUNTY, Iowa (KWWL) — After a record-breaking winter of snowfall across Eastern Iowa and now a rainy spring season, The Coralville Lake and Reservoir are filling up, leading the Army Corps of Engineers to increase outflows at the Dam.
Currently, the reservoir is sitting around 704 feet, just 8 feet short of flood at 712 feet.
It was a busy Monday at Coralville Reservoir as people soaked up the sun despite multiple flooded out campgrounds around the lake.
“We’re pretty much peaking right now at about 704.7 feet or so. Our crest should be happening today or tomorrow,” said Army Corps of Engineer Operations Manager, Dee Goldman.
Outflows at the Dam have to be carefully monitored and controlled as to prevent flooding both up and downstream. Goldman said it’s a balancing act and that’s what they’ve increased outflows.
“Now a cubic foot of water is about 8 gallons of water. So we had over 30,000 cubic feet per second coming into the reservoir. We increased our discharges to 10,000 CFS out of the reservoir, so there were an additional 20,000 CFS that the folks in Iowa City, Hills, Lone Tree, and those areas down there were not seeing.”
This time is the second time outflows have been increased from 6,000 CFS to 10,000 CFS this season and Goldman said they’ve noticed higher inflows as well.
“We’re doing very well being efficient getting the water away from our homes and from our fields and things of that nature but it definitely impacts the river which means those levels are going to come up a little more frequently, they’re going to come up faster,” said Goldman.
That’s why the Army Corps of Engineers is re-evaluating the regulation manual, made in 2000, that dictate the outflows.
“We met with our stakeholders locally and downstream to get their input. It’s vital that we have that information to know at what levels is infrastructure is impacted,” said Goldman.
Right now they’re taking that feedback and creating models to see at what number does increase outflows created unwanted flooding downstream.