Looking for Sound Flood Alternatives

For a slightly different version, see Jim Throgmorton. 2008. Iowa City Press-Citizen (June 18): 15A.

On the morning of Saturday the 14th of June, I passed by a man who was saying, “It is obvious what the city should do: it should build dikes all along the river. That would keep the water out.” He clearly meant permanent levees, like one finds along the Mississippi in south Louisiana. I immediately thought, no, that would be precisely the wrong thing to do. But I did not reply. Exhausted and depressed from filling sandbags and then seeing floodwaters overtop or circumvent some of the temporary walls we had built, I felt there was nothing I could say or do that would make any difference.

That was exhaustion speaking. Feeling better rested now, I realize I that my role is to help all of us look ahead and, especially, to think clearly about some key questions that will occupy our collective attention for many months to come: first, what should we do after the floodwaters recede, and second, by what process should we answer that question?

The man’s claim draws attention to one alternative course of action: to build permanent floodwalls. But surely there are others. What are they? What likely consequences should we take into account when choosing among alternatives? How shall we decide which consequences matter most? Who would benefit and who would lose from any particular choice? Who should? Planners, engineers, and other experts are trained to ask these kinds of questions, but they should not be expected to answer all of them. Rather, we will need to devise a collaborative planning process that involves experts, stakeholders, and the lay public.

In my view, enclosing the river in parallel floodwalls is a bad idea for at least three reasons. First, it would destroy the greatest asset Iowa City, Coralville, and the university have: the view of a lovely river winding through the heart of town. Second, it can lead to even worse flooding in the event a levee fails. (The flooding of Highway 6 in Coralville exemplifies this kind of consequence.) Third, floodwalls only exacerbate the consequences of flooding for people who live downstream from the diked area. We all live downstream from somebody else, don’t we?

This notion that we all live downstream points toward a second alternative: to eliminate existing structures in the floodplain and to use the land only in ways that can accommodate future flooding. As parkland, for example. For those of us in the Iowa City/Coralville area, this would include the Coralville strip, the Iowa River Landing development, the Normandy Drive and Idyllwild residential areas, large parts of the University of Iowa campus, the Thatcher Trailer Court, and many other places. Just naming these areas reveals that this alterative would have to be refined.  Thus a third alternative would be to rehabilitate some damaged buildings in the floodplain, but rebuild them so that they can withstand equivalently severe flooding in the future.

How severe might some future flood be? Can the risk of equivalent (or worse) flooding in the future be reduced through actions we can take in the present? As suggested earlier, other people are better prepared to answer these questions than I am, but I do know that the long-term conversion of tall grass prairie and wetlands into corn and soybean fields has (when coupled with increased coverage of land with concrete and asphalt) had the effect of reducing the soil’s ability to absorb rainfall and slow runoff. These facts point to a fourth alternative: find more ecologically sound ways to accommodate predictable variations in precipitation.

Other alternatives exist. We should explore them wisely. As my own responses suggest, this kind of wise exploration must be informed by a range of experts, but it will also need to reflect the values of the diverse people of the University and the Iowa City area. Instead of diving headfirst into a murky lake of floodwalls and dams, we need to look ahead and plan collaboratively.

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