For Sustainable Flood Control, Think More Expansively

For a slightly different version, see Jim Throgmorton. 2008. The [Cedar Rapids] Gazette (September 14): 8A.

The June flood inflicted great harm on the people of Cedar Rapids, and many residents and business owners understandably feel a profound sense of loss, grief, and (in some cases) anger. Those who have been harmed want things put back together, as quickly as possible.

As an Iowa Citian who teaches at the University of Iowa, I understand the sense of loss and desire for rapid repair. I am also very conscious that Cedar Rapids suffered far worse damage than did my city and university.

Thus it was with considerable interest and hope that I read Rick Smith’s August 30 article in The Gazette about a presentation that a team of consultants (Sasaki Associates, Stanley Consultants, and the Corps of Engineers) has just made to the Cedar Rapids City Council.

According to Smith’s article, the team evaluated 22 alternatives in terms of their effectiveness at protecting Cedar Rapids from a flood as bad as one that occurred in June, and in terms of how long it would take to gain approval for each alternative and bring it to fruition. Smith’s story also implied that the team used benefit-cost analysis to evaluate the alternatives. Of the 22 alternatives it considered, the team reportedly identified higher levees and floodwalls, river widening, and diversion channels as the most effective tactics.

I did not hear the team’s presentation and have not had an opportunity to read details about its assessment, but based on Rick Smith’s report I would encourage the Council and people of Cedar Rapids to think much more expansively.

A more expansive approach would address four key points. First, any consideration of alternatives should seriously consider the effects of the alternatives on downstream users. If you were a resident of New Orleans, for instance, how would you feel if you learned that people living upstream were planning to speed the flow of water down the Mississippi toward your town?

Second, it appears that the team did not evaluate the potential effectiveness of increasing the water retention capacity of farmland upstream of Cedar Rapids. Much of June’s flooding in Cedar Rapids resulted from accelerated run-off from bare, water-logged fields. Rather than accelerating the flow of water through Cedar Rapids, the people and Council should explore ways of helping farmers slow the flow. Financial incentives for slowing that flow ought to be evaluated carefully.

Third, the team has apparently concluded (or been instructed to assume) that the way to solve the flood problem is to keep floodwaters away from the city’s buildings. I would encourage the people and Council of Cedar Rapids to consider the possibility of redesigning those buildings to be flood resilient. By flood resilient I mean designed to live with natural and inevitable flooding rather that try to “solve” the flood problem by speeding the water downstream. There is a substantial and growing body of experience with this kind of design, both in Europe and in Southeast Asia.

Fourth, the team might be putting far too much weight on the Corps of Engineers’ benefit-cost assessment methodology. While commonly used, benefit-cost analysis is a deeply flawed tool. Its most important flaw lies in the way it converts normative and political questions into ones that appear to be purely technical. The discount rate is crucial in this regard, as is the extent to which unpriced negative effects (or “negative externalities”) are taken into account.

When the team’s assessment of flood control alternatives is considered in light of these four points, one crucial insight can be derived: the assessment has taken place at an inappropriate spatial scale. Rather than limiting the evaluation of alternatives to the scale of Cedar Rapids, the evaluation should be conducted at the watershed scale. If assessed in terms of the flood control capacities of the Cedar River watershed, upstream and downstream users could be brought into a collaborative learning and planning process with the people and Council of Cedar Rapids.

I am in no position to make promises, for I am writing simply as a fellow eastern Iowan, but I do know that the University of Iowa has an outstanding interdisciplinary team of scholars and researchers who could contribute to that collaborative effort. If asked, I bet they would join in the effort.

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