Dennis Keeney: Flooding might be the ‘wave’ of the future
By Dennis Keeney
Special to The Tribune
“Living with floods involves two broad activities: better managing the risks and taking steps to reduce our vulnerability, and better managing the landscape to reduce the magnitude and destructive power of floods.” — Connie Mutel, Epilogue, “A Watershed year: Anatomy of the Iowa Floods of 2008.”
In the spring of 2010, The University of Iowa Press published “A Watershed Year: Anatomy of the Iowa Floods of 2008.” Connie Mutel edited this outstanding book. It should be required reading for those concerned with policy-making to address our recurring big floods. But we continue to battle day-to-day and event-to-event. Iowa State University officials talk of shoring up University Avenue in Ames, and the university and businesses clean up the damage. Who’s really hurt are the hundreds who have major property damage; basements, valuables and feelings of security are destroyed.
Are the Iowa cities that sit on large- or medium-sized river basins doomed to relive the experience of large floods regularly? No matter how much infrastructure we build to withstand the onrush of streams and rivers, flooding might be the “wave” of the future. In June 2008, the rivers of eastern Iowa created floods of epic proportions. In August 2010, the rivers of central Iowa did the same. What is going on? After the unprecedented statewide flooding of 1993, Iowans assumed we had seen the worst and returned to business as usual. How wrong can we be?
Rivers are not static. They are constantly eroding and reshaping their channels. When water flowing into the river exceeds the capacity of the channel, rivers use the naturally created floodplain to store the extra water. When rivers are denied access to the floodplain, or structures are built in the floodplain, we have a flood. Floods are natural, part of the water and biodiversity cycles. When we get in their way, damage occurs.
The climate of the Corn Belt is conducive to violent weather: high winds, tornadoes, blizzards, drought and intense rainfalls. The rainfalls seem to be the cause of much of our angst, especially recently. Reasons for the “unprecedented” floods include the possibility of major climate shifts, changes in land use, especially in agriculture, and lax urban building codes and poor storm management. I will take a quick look at these as space permits.
Probably the most sensible way to avoid flood damage is to get out of the way. But cities are not easy to move. Removing homes and businesses is a slow, expensive process, complicated by the private property ownership and by a multitude of government regulations. When public buildings are involved, such as Hancher Auditorium in Iowa City and Hilton Coliseum in Ames, public funds must be used to restore the buildings, diverting resources that are desperately needed for education and research.
A recent news release indicated a new Hancher will be built, presumably out of harm’s way, and Hilton Coliseum and presumably also the Scheman Center will be protected by higher flood barriers (levees), though the latter is not clear.
ISU’s proposed solution — deny the river its flood plain — is not really a solution. No doubt this would lessen flood damage to the ISU complex, but it would certainly increase flooding in other areas of the flood plain with unpredictable results. The river will have its way.
A better alternative, but one that might now be impractical, is to increase storage on the land. Laura Jackson, a professor of biology at the University of Northern Iowa, and I discuss this approach in chapter 24 of the book I referred to earlier. Most of the watershed above Ames is agricultural. It has been altered in ways that lower the retention of water and hasten flash floods. Tile drainage, wetland and prairie destruction, stream channeling, and, of course, the annual corn and soybean cropping all hasten the movement of water through the watershed.
Similarly, Ames, and most other cities, was not designed with floods in mind. Water runoff must be decreased relative to infiltration in both urban and rural landscapes. Our manicured, reconstructed lawns are nearly as impermeable as the concrete they drain into.
Changing our urban and rural landscapes is daunting. Some regions have gone together to plan for flood mitigation. A regional flood control effort for the Story-Boone County region could identify new roads and bridges that could be designed to provide storage and locate flood plains where flood levees could be removed, giving the river a chance to recover its flood plain.
Finally, are flood frequencies and intensity partly a result of climate change? Eugene Takle examined this question in a remarkably clear manner in his chapter of the “Anatomy of the Floods” book mentioned previously. Cedar Rapids’ average annual rainfall has increased more than 9 inches over the past 113 years and now stands at 37 inches per year. More rain is falling in the late winter, spring and early summer and rainfall events are becoming more intense. These trends were predicted by climate models, and they likely will continue in the foreseeable future. Takle writes that “the dice have been loaded toward a higher probability of extreme flood events.” Now with three major floods in 17 years, it would seem public and private decision makers should take heed.
In summary, floods will happen. Climate change will likely cause further increases, and our rural and urban landscapes have been so modified as to make lessening the impacts of floods difficult. History tells us we will recover from the floods, get enough federal aid and insurance money to repair the damage, and move on with little thought to the next flood. We deserve better.
Dennis Keeney was the first director of the Leopold Center for Sustainable Agriculture and is an emeritus professor at Iowa State University. He resides in Ames and can be reached at firstname.lastname@example.org.
*This article was used with permission by the Ames Tribune and Dennis Keeney.