Vince Neary, an associate professor of civil and environmental engineering at Tennessee Tech University, says that a mega-project to change the course of the Mississippi river is the only way to protect the Louisiana coast. It’s estimated that Louisiana loses 24 square miles of coastal wetlands each year – the equivalent of a football field every 30 minutes – due to loss of sediment buildup that used to occur naturally. “If you really are serious, that’s how dramatic the plan has to be,” said Neary. “Up until now, the constraints of special interests of all types have driven the solution to piecemeal wetland mitigation and restoration projects. Itsy-bitsy fixes won’t cut it anymore. We have the science and engineering tools to develop and implement a viable strategy; but do we have the political will to do what it takes?” said Neary.
Neary says that the river management techniques employed over the past 50 years have been in part responsible for the devastation that occurred last year. Levees, which protect economic interests and personal safety, have also stopped the natural sediment accretion process that builds coastal marsh. Instead, the sediment is jetted out into the gulf and without sediment; the coastal marsh subsides and erodes, becoming open water.
“Why not let nature take its course?” asks Neary. Adding that very little about the way the Mississippi currently flows is natural; “The natural process has been arrested for decades to protect cities, promote navigation and reduce flood damages. Had nature had its way, New Orleans and Baton Rouge would be stranded major shipping ports. The main challenge that comes with this solution is how to maintain the navigation channel that supports the transportation of oil, gas, grain and other commodities,” explained Neary. “We also have to entertain augmenting sediment and freshwater diversion through the Atchafalaya River and Bayou Lafourche, distributory channels that discharge west of the Mississippi River outlet.”
“Traditionally, we had to be very conservative and not take chances with large-scale changes in river systems, but better modeling tools allow us to consider broader options that take in environmental concerns, like preserving the salt marshes, while at the same time maintaining acceptable flood protection,” Neary said. “Environmentalists have been marginalized on this topic to a large extent for decades, even though these management and restoration issues have been on our radar for a long time. Only in the last five years or so, and certainly after Hurricane Katrina, have those with an economic stake in the area started to listen and communicate with environmentalists.” The group’s map and recommendations will be presented to Louisiana’s governor on June 1, the official start of hurricane season.