Iowa Flood Center receives grant to draw floodplain maps
Iowa residents will be able to better determine if and how often they are likely to experience a flood thanks to a grant recently given to the University of Iowa’s Iowa Flood Center.
The center, created after the flooding in 2008, received $10 million in Community Development Block Grant money to fund the Iowa Floodplain Mapping Project.
Researchers will use the funding to create floodplain maps of the 85 Iowa counties declared federal disaster areas during the 2008 flood to be available on the Iowa Flood Center’s website.
“These maps will become a basis for a variety of regulations under the jurisdiction of the Department of Natural Resources but also for a flood-forecasting system,” said UI Professor Witold Krajewski, the director of the flood center. “There are not many states that have statewide coverage.”
An example of the Natural Resources’ regulation involves development in floodplains, including flood-proofing homes and setting requirements for buildings erected in the area.
However, most maps will be “approximate maps” — based more on assumption of where potential floodwaters would flow — instead of more expensive, detailed maps using extensive data in bigger towns such as Iowa City.
“These larger communities usually have more complicated structures,” Krajewski said. “Most of them are located near larger rivers.”
One detailed map can cost around $12,000 to $15,000 to make, said Bill Cappuccio of Natural Resources’ floodplain-management program.
“You try to [make a detailed map] only where you have a lot of risk, a lot of development, only where you need that accurate data,” he said.
Focusing on the statewide “approximate maps” is the center’s priority, as they have a broader effect and significance compared with creating a few detailed maps, said Nathan Young, the manager of the Iowa Floodplain Mapping Project.
The Iowa Flood Center is collaborating with Natural Resources to draw up the maps, and the Federal Emergency Management Agency will use them to create even more detailed maps of its own.
Data used to make the maps is first gathered using light detection and ranging mechanism from airplanes, which reflects light pulses in the direction of the device on the plane and then converts it into useful information.
The information gathered from the planes helps to make a model of an area, which is used to find data on the drainage areas and discharge of rivers. Workers can then use all of the research to make its final map.
“The more data you put into your model, the more accurate it should be,” Cappuccio said.
Until recently, FEMA required floodplain maps to be made on the county level, lacking the consideration of rivers surrounding the area, Krajewski said.
“Water doesn’t work that way,” he noted.
The Iowa Flood Center received another $1.3 million grant to be put toward flood forecasting and bridge sensors to determine the distance from the bridge to the water.
Krajewski said, later this summer, the center will deploy 50 units — mostly in eastern Iowa — and he plans to have a forecasting system in 900 communities throughout the state.
“Hopefully, next spring there will be much more of that,” he said.
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