According to new research, the Mississippi River delta will be much smaller in the future — even as the state plans to spend billions trying to rebuild it.
The researchers, led by Elizabeth Chamberlain — who is now at Vanderbilt after getting a PhD from Tulane — looked at how the Mississippi River used to build land thousands of years ago, which can illustrate how it might build land in the future. They took samples of sediment up and down Bayou Lafourche — which was the main river channel at the time.
Chamberlain found that, back then, the river built about 2 to 3 square miles of land per year.
According to the paper, Louisiana loses an average of 17 square miles of land each year, and could lose even more once sea level rise speeds up.
The state is trying to stop that — by building big, expensive diversions to rebuild lost land with river sediment. The research suggests diversions will build land, but not fast enough.
Natalie Peyronnin is a science policy expert with the Environmental Defense Fund. She says that doesn’t mean sediment diversions are futile.
“It’s quite the opposite,” she says. “It doesn’t cast doubt on diversions, it actually demonstrates the need to get them built quickly.”
Peyronnin says the if diversions are built quickly, there will be more land to protect coastal towns once sea level rise picks up.
Support for the Coastal Desk comes from the Walton Family Foundation, the Greater New Orleans Foundation, the Foundation for Louisiana, and local listeners.