There was a big meeting of scientists and engineers in Grand Forks the other day and the big speaker was a guy named Robert Twilley. He’s a Louisiana State University ecologist and research chief involved in restoration of his state’s coastal wetlands, the same one whose diminishment made flooding so bad during Hurricane Katrina.
Anyway, I thought he had some interesting points regarding the U.S. Army Corps of Engineers’ main approach to flood control, which is to use technology to tame nature, except nature can bite back in subtle ways.
The corps’ Mississippi River and Tributaries Project, the bigÂ Seven Wonders of the World-sizedÂ flood control project down there, has been a boon for the state and for the nation, turning an unpredictable river into a major route for shipment of goods from the interior of the country. The problem is it tamed the river too much.
It reduced the number of outlets in the Mississippi River Delta to a handful, and because water carries sediment, it also reduced the flow of sediments that build wetlands. Louisiana’s wetlands are sinking while sea levels are rising so a continual flow of sediment is needed for them to stay above water, according to Dr. Twilley. The wetlands, as you may know, serve as a buffer between the cities of Louisiana and the sea. As wetlands shrink, they leave cities more vulnerable to flooding during hurricane season.
This made me wonder if wetlands loss in the Red River Valley have exacerbated flooding. Theoretically, if the wetlands were still around, they could holdÂ some of theÂ melted snow in the spring or the torrential rain that falls in the early summer, reducing the amount of water that dumps into the Red River tributaries.
I didn’t find anything to that effect, but, as it turns out, there have been some studies of whether wetlands restoration would reduce flooding. These happened shortly after the 1997 flood we’re all familiar with. Anyway, here’s the end result of one of those studies:
Based on the results of this study, the widespread restoration of wetlands is not considered to be wise use of public funds for the purpose of reducing flood related damage at the watershed or basin-wide level in the Red River Valley. However, this does not completely negate the potential feasibility of wetland restoration for flood control and/or the generation of other wetland-based environmental goods and services on a more limited and site-specific basis. Therefore, more research should be conducted regarding the use and non-use values of restored wetlands and how these values change when large numbers of wetlands are restored under various restoration options. In the meantime, wetland restoration in the Red River Valley should probably only be conducted in cases where simple restoration on low cost land can provide two or more additional feet of available storage bounce, have clear impacts on localized flood damage, and provide the additional (non-flood related) benefits. These scenarios are likely to occur only at a selective number of locations rather than across entire watersheds.
I don’t have time to read the entire thing, but my skimming shows that the problem is the restorable wetlands in the study area — the authors didn’t look at the entire valley — didn’t have the volume needed to reduce water levels significantly in major floods.
On the other hand, there is a proposal out there that sort of mimics wetlands: The Waffle Plan at UND’s Energy and Environmental Research Center. The plan would pay farmers to temporarilyÂ store water on their fields and not drain it.