It was just five years ago that Iowa was awash in flood water. Many people are familiar with the dire scenes from Cedar Rapids, where record floods forced the evacuation of 10 percent of the city’s residents on June 13, 2008, swamping the downtown and causing extensive damages. Plenty of other Iowa communities suffered as well, however. Cedar Falls, 90 miles north of Cedar Rapids along the same Cedar River, struggled to contain flood waters that overwhelmed its north side and almost overtook its downtown. To the southeast, Iowa City watched the Iowa River flood major University of Iowa buildings like Hancher Auditorium and the Iowa Memorial Union and learned, maybe, that the university had invested in too much real estate on the riverfront. Across the state, the rivers swelled and dozens of small towns coped with mud, pollution, and lost memories.
On Friday, May 31, I joined a panel on water management policy at “Five Years Out,” a one-day conference at the National Czech and Slovak Museum and Library in Cedar Rapids that examined Iowa’s past and future with regard to these issues. As if on cue, nature responded by sending a line of thunderstorms to assault the area the day before, accentuating the moisture in soil that had already become a huge, wet sponge throughout the spring. The Dubuque St. entrance to downtown Iowa City from I-80, always a flash point because it closely parallels the Iowa River, was closed before the day was out. As Yogi Berra would have said, it seemed like déjà vu all over again. Fortunately, the sun triumphed on Friday, and Iowa got a reprieve. Summer could still be challenging.
What I found most revealing was the information shared by William Gutowski and Rick Cruse of Iowa State University. Gutowski teaches in the Department of Geological and Atmospheric Sciences and has been tracking data on Iowa’s changing climate for some time. He discussed the seeming contradiction of Iowa suffering both increased propensity for extreme precipitation events, leading to flooding, and increased propensity for drought. The two possibilities are not mutually exclusive or contradictory, however. Higher average temperatures lead to a situation in which the atmosphere is capable of containing higher amounts of moisture because warmer air can hold more moisture before being forced to dump its load. That also means that storms become worse when they do occur. Gutowski showed that average annual precipitation in Cedar Rapids had increased between 1890 and 2010 from 28 inches to 39 inches per year. If global warming pushes that trend even further, Cedar Rapids and the rest of Iowa can expect more extreme weather of both types over time. That means, in part, that the so-called 100-year flood event, or that flood having a repetitive one percent chance of occurring each year, may well become more frequent. The record-breaking flood of 2008 could well become more common. The only thing saving the city in the future is the fact that it has given the Cedar River “room to breathe,” as various speakers put it, through the city’s acquisition of more than 1,300 flooded parcels in the floodplain since 2008, thus removing a good deal of vulnerable housing from the prospect of future damage. Rick Cruse, an agronomist, accentuated Gutowski’s data with significant data on how land use and land cover affect water infiltration into the soils and water tables. Forcing increased runoff with vegetation or impervious surfaces that do not hold the water as well serves to increase our propensity for flooding. As it turns out, woodlands do the best job of absorbing rainwater, while ubiquitous Iowa crops like corn and soybeans have a more questionable track record. The result is that Iowa may need a serious debate about farming practices, including crop choices and rotations, in order to confront its flood threat adequately for the future. That will not be an easy debate because it affects serious economic interests in the state. Yet it may be the most important debate Iowa can have about its climate future.
The University of Iowa Public Policy Center, which presented the conference, will be posting the PowerPoint presentations and videotapes of the sessions on its website in coming days. For those the least bit serious about exploring the implications of these issues, I urge you to follow the link above and check it all out.
Jim Schwab