A look back
This past weekend’s rain left 2 feet of standing water in Marsha Darby’s yard just outside of Iowa City. And though it had subsided to a few inches on the squishy turf by Monday, Johnson County remains under the threat of a flash-flood watch.
“You should’ve been here over the weekend — there was over 2 feet of water out here. It’s pretty saturated,” said Darby, a resident of Iowa City Regency Community Mobile Home Park. “It’s just really inconvenient. I’m still repairing my house from last spring.”
As she continues to deal with last year’s damage, the Coralville Reservoir is dealing with high water levels in Lone Tree. Officials with the U.S. Army Corps of Engineers station at the Reservoir are planning on letting 10,000 cubic feet of water per second flow down the Iowa River later this week — right toward Iowa City.
“Low elevation areas such as City Park will be affected,” said the station’s natural-resources specialist, Randy Haas. “We plan to start opening the spillway later this week.”
The outflow is only at 1,200 cubic feet per second, which functions to prevent too much water from reaching the Lone Tree Corps station down the river. The Corps monitors water levels at Lone Tree and Wapello and, to some degree, can control the effect and amount of floodwater.
“The Reservoir lessens the impact,” said Haas. “We cut the flow back based on measurements at points in Lone Tree and Wapello.”
According to the Corps website, the Reservoir, an integral part of flood prevention, is expected to reach nearly 700 feet by March 14. That’s 12 feet under the spillway’s crest. Around the same time last year, that number was around 683 feet.
During last summer’s floods, the water overflowed the spillway at 717 feet on June 15, 2008.
“There’s no concern [about flooding] at this point,” Haas said. “The weather is looking favorable, a couple of dry days. Our outflow will be boosted later this week.”
Though residents are concerned about flooding, Iowa City Mayor Regenia Bailey and City Manager Michael Lombardo both say, to their knowledge, this is typical spring weather.
Haas agreed the recent weather is typical low-level spring flooding. There is no major indication of flooding apparent, he said. With the river levels rising, concerns over flooding rise, too, though UI geography Professor George Malanson said there is nothing extraordinary about Iowa City’s geography that would put residents at risk for a repeat of the 1993 and 2008 floods.
“The Iowa City area and particularly areas north of us received a lot of rain throughout April,” he said. “It really depends on what happens between now and late spring.”
The weather and geography are two important components of flood prediction. Malanson noted that the snow and rain have dissipated in small amounts at a time and are less threatening than precipitation like last spring’s. One important thing to remember, though, is floods are part of nature.
“We’ve built houses and university buildings in floodplains, which is not unusual,” he said. “Iowa City has a small floodplain, and plains get flooded.”