Unnatural Disaster: Human Factors in the Mississippi Floods

Abstract

It’s happened again. For the third time in 15 years the Mississippi River massively burst its banks this spring, inundating tiny Missouri towns such as Winfield (population 720) and Foley (population 178), causing potentially billions of dollars’ worth of destruction—although the damages are still being assessed—and hiking corn prices to $8.00 a bushel in the wake of the lost crop. On 22 April 2008 scientists with the U.S. Geological Survey (USGS) measured the largest water volume on the lower Mississippi River since 1973, with a flow of 1.8 million ft3/sec, enough to fill more than 20 Olympic-size swimming pools in 1 second. The environmental fallout from the 2008 floods is still being assessed. The danger of floodwater is not simply that its level is too high, says Robert Criss, a geologist at Washington University. “Floodwaters are heavily polluted with sewage and filth, commonly bearing counts of coliforms, fecal Streptococcus, and other bacteria of many thousands per deciliter,” he explains. “The waters are laden with contaminants including agrochemicals, oils, detergents, and toxic metals. They are highly turbid, typically bearing particulate loads a hundredfold or more higher than normal river waters.” Those pollutants, contaminants, and sediments can be carried into homes, where the lingering dampness promotes mold growth. Moreover, floodwater pools trapped behind failed levees serve as breeding grounds for mosquitoes, flies, and other disease vectors. Meanwhile, observers are asking how such devastating floods could have occurred again so soon. The massive flooding is attributed largely to torrential spring rains in the Upper Mississippi Valley, which Paul Rydlund, a supervisory hydrologist with the USGS Missouri Water Science Center, says were even greater than those preceding the record-breaking 1993 Midwest flood. But as heavy as those rains were, the question in the minds of some is whether they were made worse by structures such as levees and other man-made interventions wrought upon the Mississippi River over time.