The increased prospect of spring flooding this year has University of Iowa and local government officials on guard.
Officials said they are concerned about current conditions — highly water-saturated ground and significant amounts of snow cover. But Don Guckert, the UI associate vice president for Facilities Management, said the risk of flooding this spring is still relatively low.
The Army Corps of Engineers is in its annual process of lowering the Coralville Reservoir by 4 feet, said John Castle, the Army Corps of Engineers’ operations manager for Reservoir.
Typically, the Corps waits until ice melts on the lake before lowering water levels to avoid harming wildlife. It’s also a safety precaution — if someone ventures onto the lake when there is no water supporting the ice, Castle said, he or she has a greater risk of falling through.
Officials began lowering the lake Feb. 15, Castle said. The process started earlier this year because of increased flood risk.
Maren Stoflet, a hydrologist with the National Weather Service, said river levels have been above normal and a significant amount of winter snowfall has not melted — conditions that contribute to an above-average chance of flooding.
A slow snowmelt could be facilitated by above freezing temperatures during daytime hours and below freezing temperatures during the night. Heavy precipitation events could lead to flooding, Stoflet said.
The rate of snowmelt in the area will be a significant factor if any spring flooding occurs, Castle said.
“If it all goes in a few days with a warm rain, there will be a lot of problems,” Castle said. A more gradual snowmelt will create fewer issues, he said.
When looking ahead, Guckert said, his office pays close attention to weather forecasts, lake elevations, and water outflow at the Coralville Reservoir. Officials from UI Facilities Management and the Corps of Engineers stay in touch leading up to flood season.
In the event of a flood, Guckert said the UI can deploy barriers, called HESCO walls, to cover most of the riverbank in two days. The blockades look like 4-by-3 feet wire baskets filled with sand and are quicker to set up than a sandbag wall. The UI used these barriers during the floods of 2008.
Despite a fairly optimistic outlook, Guckert said, officials are going to pay close attention to the variables.
“We’re not going to let our guard down,” he said.