environment
4
A Flood of Concern
Cc
Ashley Berthelot
What happens when the Mississippi River overflows its boundaries, causing the spillway systems in Louisiana to be opened? The Mississippi River has long held an almost mystical place in our imaginations. As the most powerful river in the United States and the fourth-longest river in the world, its position in music, literature and folklore is understandable. But those living near it — and the scientists who study it — have a different kind of respect for the mighty river, which in the spring of 2011 reminded us that manmade boundaries cannot wholly restrict the path of a river on the rampage … and sometimes, those structures actually produce unintended consequences of their own. With Louisiana’s wetlands already delicate and disappearing at the rate of a football field every 40 minutes, understanding the full impact of opening manmade flood relief structures is more important now than ever – and might even hold the key to restoring what once was an integral part of the state.
When opened, the Bonnet Carré spillway, located near New Orleans, Louisiana, delivers floodwaters from the Mississippi River into Lake Pontchartrain through a total of 350 bays. In April and May of 2011, when a combination of unusually high precipitation and annual snowmelt caused the river to swell well beyond its boundaries, inundating highly-populated areas like Nashville, Tennessee, the Army Corps of Engineers was forced to open 330 bays in order to divert high water from New Orleans and Louisiana’s capital city of Baton Rouge. But, many wondered, at what cost? A team of LSU researchers, including geologist and principal investigator Samuel Bentley, decided to find out. Bentley, a marine sedimentologist whose most recent line of research focuses on the fate of the Mississippi Delta, immediately contacted his National Science Foundation program director,