This article first appeared in the St. Louis Beacon: July 3, 2008 - As the turbid, polluted waters slowly recede, it is time to reflect on why 2008 was another disastrous flood year. Why, indeed, did record and near-record flooding strike the Midwest so soon after 1993?
The sad truth is that the flood of 2008 should be no surprise. Experts have long warned that floods are becoming more frequent and more severe, and that this succession of aggravated misfortune is caused by Man.
The factors that worsen flooding are easy to understand. Great reaches of Midwestern rivers are only half as wide as they were historically, so they must rise higher to accommodate flood waters. Now transformed into narrow navigation slots, constrained by huge rock piles called wing dikes, major rivers must flood to far higher levels than they formerly did. Levees have been built ever higher to constrain these raging waters, even as we have built new ones to lure risky development to floodplains.
Urban sprawl has consumed watersheds that were once forests and farms, so rain runs off the land faster and in greater quantity. Severe storms now deliver huge rainfall amounts in brief time. It is inevitable that this combination of effects has forced flood waters to rise.
So, what can we do?
First, we must not further exacerbate the problem, and the best way to start is to acknowledge that a problem actually exists. The standard description of this or that as a 200-year flood, or a 500-year flood, or a 500-year levee, is so fraudulent that it must be eliminated. The underlying calculations are based on erroneous statistical assumptions, and they mislead people into underestimating flood risk and overestimating flood protection.
Second, we must cease building new infrastructure on the best farm land in a starving world.
Such development is made possible by the misleading language mentioned above, jargon that permits public financing and insurance protection to be secured for construction projects, making fortunes for a few while burdening the rest of us with problems and debt. Floodplain development should be recognized as geologically stupid, economically unwise, environmentally harmful, and pernicious to mankind.
Third, the cumulative impacts of our works, including higher levees, new navigational structures, and lost floodplain acres, need to be considered in all our future plans. For example, if some levees must be made higher, others will need to be lowered or gated.
Fourth, we should rethink whether vessels on our major rivers need to be as large as they currently are. Smaller vessels operating on rivers that flood more naturally would provide more jobs for rivermen, and the enriched bottomland would increase crop yields in years without flooding. In the long run, water quality would be improved.
Finally, restoration of floodplain wetlands and riparian buffer zones is a proven way to decrease flooding while enhancing recreational values and increasing wildlife populations. The Big Muddy Refuge on the Missouri River clearly serves these diverse purposes.
Our misguided efforts to "control" our great rivers have instead made them more chaotic and unpredictable. Better planning would not only offset these tragic trends, but would be environmentally and economically wise.
Robert Criss is a professor in the department of Earth and Planetary Sciences at Washington University. He is the coauthor of the 2003 book, "At the Confluence: Rivers, Floods, and Water Quality in the St. Louis Region."