Thoughts go out to Harvey flood victims

Our thoughts and deepest sympathies are with those impacted by the devastating floods caused by Hurricane Harvey.

Texas National Guard soldier helping with flood rescue.


Iowans remember the 2008 floods that wreaked havoc across our state. Through the chaos, we came together and built back a more resilient Iowa.

Iowa Flood Center experts reflect on the extreme flooding in Texas:

IFC Director Witold Krajewski compares Harvey flooding scenarios to Des Moines. View his interview with ABC Channel 5.

IFC Associate Director Nathan Young compares Iowa’s 2008 flood experience with that of the flooding in Texas. View his interview with KWWL-TV.

IFC Director Witold Krajewski describes the flooding in Texas as it relates to the 2008 catastrophic flood event in Iowa. View his interview with KFXA/KGAN-TV.

IFC climate research expert Gabriele Villarini offers some perspective on the flooding in Houston,Texas in response to Hurricane Harvey. View the interview with KCRG-TV.

IFC reflects on ’08 floods and Texas flooding,Published on: August 29th, 2017

Statewide floodplain maps near completion,Published on: November 29th, 2016

Website offers instant flood information for entire state Iowa,Published on: April 4th, 2016

Flood Maps Project Gains Momentum

Floodplain Iowa

The project will map all streams draining more than one square mile.

Easy-to-access, science-based information is one of the best tools we have to defend against flooding, says Iowa Flood Center (IFC) Associate Director Nate Young.

Working with the Iowa Department of Natural Resources, Young’s team of 16 IFC engineers, GIS analysts, and students is about halfway through a six-year project to develop upda
ted floodplain maps for the 85 Iowa counties that were declared Presidential Disaster Areas after the 2008 Iowa floods. The remaining 14 Iowa counties will be mapped by the U.S. Corps of Engineers.

“The maps will provide Iowans with good information concerning flood risk in their own communities, so they can make informed land-use and land management decisions,” Young says. The maps will define the boundaries of flooded areas for 100-year (1 percent annual chance of flood) and 500-year (0.2 percent chance) floods.

Iowa Flood Maps Online

The new draft flood maps are being posted online at as they become available. The flood mapping team began its work in southwest Iowa and is working its way northeasterly across the state (Iowa Floodplain Mapping progress map).


Floodplain maps delineating the 100-year (blue) and 500-year (orange) floodplain will be publicly available online.

The easy-to-use Google-maps based interface allows Iowans to directly access information about their flood risks. While the entire library of IFC flood maps is being developed to the standards of the Federal Emergency Management Agency (FEMA), not all of the maps will be adopted by FEMA as regulatory documents. The remaining, non-regulatory maps will be available on the website to provide accurate information to Iowans, but will not be considered FEMA regulatory maps.

Partnering with the DNR

The IFC researchers are using laser radar (LiDAR) data made available by the Iowa DNR to map all streams draining one square mile or more. LiDAR is a remote-sensing technology that allows researchers to develop precise digital elevation models of the land surface. LiDAR data allow the team to describe Iowa’s river and stream networks, develop computer-based flood simulations, and delineate floodplains with reasonable accuracy.

Young, who is also an associate research engineer at IIHR—Hydroscience & Engineering, says the scope of the project is enormous. “Scaling the project up to the entire state and developing and managing such a large volume of data is daunting,” Young says. “We have hired a large number of engineers, GIS staff, and students dedicated specifically to the project. Our partnership with DNR has also been a great help in that regard.”

Public Feedback

According to IDNR Floodplain Mapping Coordinator Scott Ralston, public meetings in each county after the draft flood hazard maps are published will give Iowans a valuable opportunity to learn more and offer comments and feedback.

Plans are underway to expand the project to provide more mapping projects of particular interest to farmers. Duane Sand of the Iowa Natural Heritage Foundation hopes to raise $1.2 million for an additional two to five years of work to develop flood maps for the 2-, 5-, 10-, 25-, 50-, and 200-year floods.

With just under three years to go before the original mapping work is done, Young says he’s feeling confident that his team will succeed in completing the assignment on time. “We’re gaining momentum,” he says.

Cedar Valley Has New Tool in the Fight Against Floods Cedar Falls Courier,Published on: June 17th, 2014

New Flood Preparedness Tool for Mason City Weather Whisper,Published on: May 7th, 2014

New Flood Preparedness Tool for Mason City Now,Published on: April 23rd, 2014

Flood Inundation Map: Mason City

Center Develops Web-Based Flood Map for Mason City

A new web-based flood preparedness tool developed at the Iowa Flood Center (IFC) can help Mason City residents know what to expect from the Winnebago River at times of high flows.

The new Mason City flood inundation maps are available to the public on the Internet through the Iowa Flood Information System (IFIS), an interactive Google Maps-based online application.  Homeowners and business owners will now be able to see how predicted flood levels might affect their individual properties.

Nathan Young, IFC associate director, says improving flood preparedness is one of the IFC’s key goals. “This is an opportunity for us to produce research that is useful and meaningful for Iowans. Our high-resolution web-based flood inundation maps illustrate where floodwaters will go under different conditions.

He adds, “We believe this extra measure of preparedness can save property, resources, and lives.”

With these maps, Iowa Flood Center researchers are taking the guesswork out of future flood scenarios for Mason City and several other Iowa communities. When floods struck Iowa in the past, uncertainty was part of the problem. Property owners were unsure if projected floodwaters would reach them, and how they ought to prepare.

“The models and information provided by the Iowa Flood Center are another set of tools for our city to use in planning for a flooding event,” says Mason City City Administrator Brent Trout. “We need information like this to better understand and predict where flooding will occur first, so we can put our resources at the correct location.”

Trout adds, “We appreciate IFC completing this for our community.”

IFC engineers use bathymetric surveys of the riverbed to determine the shape of the channel and aerial LiDAR (laser radar) data. With this information, researchers can create very detailed maps of the streambed and floodplain to illustrate where floodwaters will go under different conditions.

The detailed flood inundation maps are available online for a number of Iowa communities including Cedar Rapids, Charles City, Des Moines, Elkader, Hills, Iowa City, and Waterloo/Cedar Falls. Additional communities will be mapped in the future.

To use the interactive online maps, visit the Iowa Flood Information System (IFIS). Launch IFIS, and click “Flood Maps” to view the inundation maps.

The Iowa Flood Center is part of IIHR—Hydroscience & Engineering, a unit of the UI College of Engineering. The IFC was created in 2009 in the aftermath of the historic 2008 Iowa floods and is supported by state appropriations to improve flood monitoring and prevention in Iowa.

MEDIA CONTACT: Sara Steussy, Iowa Flood Center, 319-384-1729,