Nick Fetty | February 12, 2015
The Midwest has seen a greater number of serious floods in recent decades compared to previous years, according to a report by researchers at the University of Iowa.
“It’s not that big floods are getting bigger, but that we have been experiencing a larger number of big floods,” said Gabriele Villarini, UI assistant professor of civil and environmental engineering and a co-author of the study.
The report – which was published this week in the journal Nature Climate Change – examined 774 stream gauges in 14 Midwestern states (Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, West Virginia, and Wisconsin). The researchers concluded that 34 percent of the sensors detected an increase in flooding events between 1962 and 2011. Nine percent of the gauges showed a decrease in flood events during that same time. The region including Illinois, Iowa, Indiana, Ohio, Missouri, and North Dakota experienced the greatest increase of flood frequency.
The authors wrote: “Most of the flood peaks in the northern part of the [Central United States] tend to occur in the spring and are associated with snow melt, rain falling on frozen ground, and rain-on-snow events.” However, the report “does not attempt to pinpoint precisely how climate change might be directly responsible for these increased flooding events.”
Serious floods have inundated the region in 1993, 2008, 2011, 2013, and 2014 and have caused more than $260 billion in damages between 1980 and 2013.
Funding for this research was provided by the U.S. Army Corps of Engineers Institute for Water Resources, the Iowa Flood Center, IIHR-Hydroscience & Engineering, and the National Science Foundation.
