New statewide flood mapping officially finished

New flood maps to help people know if they’re still in the path of danger and help communities better prepare for possible flooding are finally complete. And that completion comes eight years after the devastating floods of 2008.

The six-year effort to create and update flood maps statewide by the Iowa Flood Center at the University of Iowa began back in 2010. The comprehensive mapping program cost about $15-million dollars. The U.S. Department of Housing and Urban Developed funded most of the cost.

The work is so comprehensive every single stream in the state, that drains at least one square mile of territory, is included.

While the Iowa Flood Center marked the completion of the mapping with an event on Monday, many communities have already started using the information. For instance, the city of Cedar Rapids used the data this fall to fight off the second highest crest ever on the Cedar River.

The information compiled by the flood center predicted how far flood water would spread and helped the city know where to place flood barriers most effectively.

Nate Young, associate director of the Iowa Flood Center, says some of the information used before was so old, it was almost useless.

“Using information that’s 40 years old we’ve had a lot of rainfall events, a lot of floods that have happened since then and so the statistics have changed and so we have a better understanding of our flood risk,” Young said.

The new flood maps can show the extent, and depth, of flooding if a waterway is hit by rainfall that produces as little as a 10-year event to as much as a 500-year flood. Not all the mapping information is online yet at www.Iowafloodmaps.org. But it should be by the end of the year.

Eventually the new flood mapping information should be used by the government to determine who needs and who doesn’t need to buy flood insurance. And, of course, communities will rely on it to make decisions about flood plains development and flood prevention.