Image: Swirling water destroys this levee surrounding the Clarence Cannon National Wildlife Refuge in Missouri during the flood of 1993. Robert Criss, Ph.D., WUSTL professor of earth and planetary sciences, says that levees are not infallible, and he cites a number of reasons why they are problematic to communities. (Credit: Photo courtesy of USGS)
Patterns in the Midwest this spring are eerily reminiscent of 1993 and 1994, back-to-back years of serious flooding. The great flood of 1993 caused nearly $20 billion of economic damage, damaging or destroying more than 50,000 homes and killing at least 38 people. Parallels this year include abnormally high levels of precipitation in late winter and early spring, and early flooding in various regions. In March, Missouri, Arkansas and Illinois and the Ohio River experienced flooding. A still-unknown factor is the effect of the snow melt from upstream states on river systems this spring and summer. Wisconsin, for example, had record amounts of snow this winter. Despite the similarity in conditions and periods of flooding nearly every year after those flood years more than a decade ago, one thing Midwesterners have not learned is "geologic reality". "When people build commercial or residential real estate in flood plains, when they build on sink holes, when they build on fault lines, when they build on the hillsides in L.A. that are going to burn and burn, over and over again, they're ignoring geologic reality." "Building a levee for a community simply 'certifies' that this is a great place to build more things. The Corps of Engineers will come in and claim it's a 500-year levee, which is a claim they cannot make, yet routinely do. That just encourages more infrastructure to move into these areas." Levees cause water to rise instead of spread out, and that the cumulative effect of levees and wing dykes on the large rivers north of St. Louis is beginning to manifest itself in flooding.
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