Letting Mississippi run its natural course could save New Orleans from hurricanes

In doing so, they will intentionally flood what was originally projected to be around 3 million acres of land in a swath that would almost reach from Boston to New York City. It would be like flooding the state of Connecticut under 5 to 25 feet of water. A dozen communities and two small cities will be inundated, along with 11 major oil refineries. Citizens of the area have already moved to higher ground.

An even greater calamity

But the danger in the Corps’ bid to control Mother Nature could result in even greater calamity. The Corps could lose control of the situation and all of the mighty Mississippi could burst the old river control structure, and the full force of the Mississippi could come barreling down into Atchafalaya, never to return to its original course.

This would leave both New Orleans and Baton Rouge – key port cities – without their rivers. Billions of dollars in infrastructure and commerce would be lost, and America’s petrochemical industry would be dealt a devastating blow. Eventually, the Gulf of Mexico would flow back up the empty Mississippi river basin toward New Orleans and Baton Rouge, with unforeseen consequences.

Why no river for New Orleans might save it

But such a shift could ironically serve the long-term ecological interests of the region. Allowing the Mississippi to follow its natural course down the Atchafalaya would devastate cities, farms, and oil refineries, but it would also offer the region some long-term protection.

The Mississippi sediments that now flow uselessly into the depths of the Gulf of Mexico would start to rebuild the marshes of Southern Louisiana, creating a coastal barrier against future storms. Marshes are nature’s way of protecting coasts from hurricanes, and New Orleans knows the costs of hurricanes like Katrina all too well.

Marshes are Nature’s way of protecting coasts from hurricanes. Every mile of marsh brings down storm surges from hurricanes by a foot. If the marshes of southern Louisiana had been allowed to grow naturally, it’s fair to say that New Orleans would not have been flooded by hurricane Katrina. Coastal scientists should continue watching to see if this crisis will offer ideas for how to rebuild Louisiana’s marshes – even if that means allowing the Mississippi to change its course.

William Sargent is a Nova consultant, blogger, and author of over a dozen books about science and the environment. His latest book is “The Well From Hell: The BP spill and the Endurance of Big Oil."

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