Flood Forecast Improves, Coralville Lake No Longer Expected to Top Spillway
By Gregg Hennigan, Reporter
IOWA CITY, Iowa – Coralville Lake is no longer predicted to go over its emergency spillway, but don’t take that to mean the threat of major flooding has passed.
“It’s important for folks to understand that this is going to be a prolonged event,” Terrence Neuzil, a Johnson County supervisor serving as spokesman for the county’s Emergency Management Agency, said Sunday morning. “The (Iowa) River is going to be flooded for a while.”
The Army Corps of Engineers, which oversees the lake, is now forecasting the lake will crest at 711.5 feet above sea level on June 7. That’s down from 712.8 foot prediction made Saturday, and it is below the spillway, which is at 712 feet.
Receiving just a few hundredths of an inch of precipitation in the Iowa River basin on Saturday and dry forecasts for Sunday and Monday helped bring the lake forecast down, Neuzil said.
But the lake is still high – nearly 707 feet compared with the normal summer elevation of 683 feet – and it will be high for some time, officials said. They are expecting the flood threat to remain much of the summer, and another wet stretch like what was seen last week could send predictions soaring again.
The National Water Service is predicting the Iowa River in Iowa City crests at 25 feet, which is right at “major” flood stage, on June 4 or 5.
“We’re not out of the woods yet,” said Dee Goldman, the lake operations manager. “There’s still a very real risk there. But every little bit we can get out of the reservoir” helps.
The amount of water going through the dam’s gates, which are wide open, was 18,100 cubic feet per second Sunday morning. That’s expected to hit 19,500 cfs as the lake crests. That’s also an improvement from Saturday.
Flooding remains a concern. In addition to the flood damage and home evacuations that already have occurred, the county is keeping an eye on Winter Eagle Road just south of Terry Trueblood Recreation Area in southern Iowa City and Ely and Swan Lake roads near the lake.
The corps will close Prairie Du Chien Road near the Coralville Lake dam on June 3 or 4 as a safety measure with the water approaching the spillway.
Goldman said a lot of sightseers are coming out to the area and that impedes the corps’ work and presents a safety risk. “It is still a very dangerous situation,” he said.
The corps is moving to 24-hour operations at the lake Sunday to monitor the flood situation, including inspecting the dam and reading gauges, Goldman said. Everything is working as it should be at this time, he said.
The corps expects to close the Tailwater East and Cottonwood campgrounds near the dam on Monday. There are a few campers at Tailwater but none at Cottonwood, Goldman said.
The lake is still open to boaters, but Goldman encouraged people to stay off it. The Iowa River below the dam remains closed by order of the Johnson County Sheriff's Office. Not everyone is following that directive, though.
Iowa City police caught some canoeists in the fast-moving river Saturday, Neuzil said. They were removed but not arrested. “The message is real clear: On the river, no means no,” Neuzil said.
Three groups from two special law enforcement water teams – one based out of Cedar Rapids; the other in Johnson County – will be on the Iowa River today shooting video and still photographs of water damage.
About 30 Johnson County buildings, mostly homes, are currently damaged or under water with an estimated $2 million in damage, Neuzil said.
The worst-case scenario, based on a lake outflow of 21,000 cfs, would threaten 64 buildings and has the potential to cause $23 million in damage, he said. About 20 miles of roads would be affected by floodwaters in that situation, he said. About 15,000 tons of debris would be in the Iowa River.
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