Flood gauges going up on North Iowa bridges
By Richard Johnson
MASON CITY — High-tech flood gauges will be placed late this summer on several bridge decks in North Iowa.
Each will feature an acoustic pulse to measure how long it takes for the pulse to leave the sensor, bounce off the water surface and return.
That will show how far the water surface is below the bridge deck, said Nathan Young, a research engineer with the Iowa Flood Center at the University of Iowa in Iowa City, which is developing the sensors.
Measurements will be taken every 15 minutes and reported via cellular modem to a central server, where the information is distributed over the Internet, he said.
Sensors will be placed on the West Fork of the Cedar River near Dumont; Gates Bridge on the Shell Rock River at Greene; the Shell Rock on Packard Avenue near Greene; the Shell Rock near Rockford; and the East Branch of the Iowa River near Garner.
“Every bridge is a potential stream gauge,” Young said.
The Flood Center is under contract with the Iowa Department of Natural Resources to produce 50 sensors. The DNR will distribute them to Iowa communities.
The Flood Center, established July 1, 2009, in response to the 2008 flooding which heavily damaged Iowa City, also is involved with flood inundation mapping.
Charles City, Cedar Falls-Waterloo and Iowa City are currently on the map at www.iowafloodcenter.org/maps.
“And we’re continuing to complete a handful of other communities in the next several months,” Young said.
The Flood Center also hopes to develop a series of inexpensive soil moisture systems to be deployed statewide, “to get a better idea of how saturated the soils are, and get their predictions of rainfall runoff,” he said.
“We’re hoping to expand to a broader area throughout the state.”