IOWA CITY — Despite a deluge in Johnson County and points south on Monday, the latest watershed projections don’t signal flooding from the Iowa River, even though officials say the threat remains.
Flash flooding was another story on Monday.
“We are looking at two different fronts that we are dealing with: flooding of the Iowa River and flash flooding from the storm,” Iowa City Public Works Director Rick Fosse said. “Certainly, the latter is our issue this afternoon.”
A severe thunderstorm caused flash flooding and knocked down tree limbs. It made travel dangerous and closed several roads on Monday afternoon in Johnson County.
Calls from motorists stuck on inundated roads came from throughout Iowa City and Coralville, said Dave Wilson, coordinator of Johnson County Emergency Management. There were storm-related accidents, and a tree limb fell on a car on Sycamore Street in Iowa City, he added.
He was not aware of any serious injuries, he said.
“We try to warn people, you’re not a boat, you don’t float,” Wilson said.
The storm blew a panel from an in-progress scoreboard project at Kinnick Stadium on to vehicles below, said Steve Pradarelli, a spokesman for the University of Iowa. He said no one was injured and staff were still assessing the damage.
About 6,600 Mid-American Energy customers lost power in Johnson County on Monday, according to spokeswoman Ruth Comer. By early evening, 1,200 people remained without power with no immediate timetable for restoring service, she said.
South in Washington County, officials warned residents to avoid downtown Kalona, where main roads were underwater.
Meanwhile, the threat of sustained flooding from rising river levels remains a concern, some say, but as of now current projections suggest water will recede before causing any major disruptions.
The Coralville Dam was increased to 7,000 cubic feet of water released per second on Monday. Earlier in the day that rate was projected to increase to 17,000 cubic feet per second on Tuesday, prompting fears of pending flooding.
Iowa City officials were projecting the key arterial — Dubuque Street — to flood yet again by Wednesday. It’s been closed for extended periods due to flooding in 2008, 2010 and again in 2013.
However, new watershed models from the Army Corps of Engineers on Monday afternoon allowed officials to recalibrate the dam’s outflow plan to about 10,000 cubic feet per second on Tuesday.
Fosse said based on the new model Dubuque Street is now not projected to close due to river flooding, even though it did close for a period due to Monday’s storm. Wilson said when the outflow reaches 12,000 cubic feet of water per second, “Dubuque Street is lost.”
“Ten thousand really is not a problem for any of them,” Dee Goldman, operations manager at Coralville Lake, said of communities down stream including Coralville, Iowa City and the University of Iowa.
Projections can change multiple times a day, though, he said.
“These next 12 hours are critical,” Goldman said from his office on Monday afternoon as a thunderstorm was blowing through the area.
The lake was at about 697.48 feet above sea level on Monday, approaching the spillway’s peak of 712 feet. However, the water level is supposed to crest next week without spilling over, Goldman said.
When asked if Wilson was feeling optimistic about the news, he responded, “Optimistic? No. The word I’d use is concerned.”
Goldman met by conference call to brief local officials on conditions, and they have plans for another update on Tuesday morning.
Fosse said it’s not clear how much of the rain on Monday was factored into river level projections, and there’s forecasts for more storm systems moving across the upstream of the Iowa Rivershed.
“We will know a lot more (on Tuesday),” he said, adding, “It’s too early to speak with any certainty about the river levels later in the week.”
University of Iowa announced plans to begin placing HESCO flood barriers around its Mayflower Residence Hall, which sits east of the Iowa River along Dubuque Street south of I-80.
Weather-permitting, work to erect the massive barriers will begin Monday, said UI spokesman Tom Moore. But, because crews need to close the northbound lanes on North Dubuque Street to erect the barriers, Moore said crews might have to wait until flash-flooding concerns subside. That could mean the barriers will begin going up Tuesday morning, UI officials said.
Commuters are advised to find alternate routes in the meantime.
The barriers are being used as a precautionary measure in response to recent and forecast heavy rainfall threatening to raise water levels at the Coralville Lake and in the Iowa River in the coming weeks.
At a campground near the Coralville spillway, Marty and Diane Robertson, of Vinton, were preparing to cut short their Fourth of July, weeklong vacation. An official came through and told campers they needed to leave by Tuesday midday, they said.
“It’s disappointing, but I understand,” Marty Robertson said. “It’s not the rain here today, it’s the rain up north that we need to worry about.”