LA - Threats facing fragile lower Mississippi river delta to be addressed – and possibly mitigated – by five-year, $22 million research consortium

The lower Mississippi River delta is facing unprecedented threats, from hurricanes, rising seas, ground subsidence, diminishing river sediment, coastal dead zones – and decades of dredging. Because of dredging, the bed of the Mississippi River in southern Louisiana is so far below sea level and this year’s historic drought has driven water flow so low that the river can’t push back against salt water flowing in from the Gulf of Mexico.

Like many of the river’s other threats, this one is not unpredictable: it’s been on the horizon for decades, as the river’s navigation channel was increasingly dredged to accommodate larger and larger ships.

Nearly three decades ago, in 1987, environment writer John McPhee wrote about the danger this dredging posed. The U.S. Army Corps of Engineers has also long known that dredging left the river more vulnerable to saltwater intrusion. The threat was a “trade-off” for keeping the river’s ports competitive, wrote Chris Accardo, retired chief of the operations division for the New Orleans District Corps of Engineers, last week, in a letter that noted his agency’s openness about the situation.

“In fact, the Corps have said that a deepened river along with drought conditions have caused this current problem,“ Accardo wrote.

This summer, while actively planning for worst-case saltwater solutions in the lower river, the Corps’ New Orleans District announced the launch of a five-year, $25 million mega-study to examine and offer management recommendations for issues like this and “the change in river dynamics” for an area spanning from Cape Girardeau, Mo. to the Gulf.

A new consortium led by Tulane University and Louisiana State University, is also launching its own five-year study – thanks to a $22 million award announced today by the National Academies of Sciences, Engineering and Medicine – to increase the sustainability of the lower Mississippi River delta and the economy that relies on it.

The study by the new Mississippi River Delta Transition Initiative, or MissDelta, will focus on a narrower span of the lower Mississippi, stretching from New Orleans to the river’s end, the Bird’s Foot Delta at the Gulf of Mexico. (The Corps’ study includes an additional 1,000 miles of river up to Missouri.)

The initiative will forecast effects on the disappearing delta through the year 2100 – and then use models to test varying plans to reverse those effects, said Mead Allison, a consortium co-lead and chair of Tulane University’s Department of River-Coastal Science and Engineering.

“What’s really unique about this project is that it’s not just modeling water and sediment, it’s also economic and socioeconomic modeling,” Allison said. Information gleaned from the models will be used to predict the economic effects of different solutions, on jobs and industry within the region.

The team will include 38 investigators from research institutions and the National Academies’ Gulf Research Program, working in partnership with the Louisiana Coastal Protection and Restoration Authority and the U.S. Army Corps of Engineers, among others.

The consortium will include six historically Black colleges and universities in Louisiana and Mississippi—Southern University of Baton Rouge, Xavier University of Louisiana, Jackson State University, Grambling State University, Dillard University and Alcorn State University—as well as researchers from the nonprofit Water Institute of the Gulf, the Louisiana Universities Marine Consortium (LUMCON) and four other Southern schools: the University of Southern Mississippi, the University of Central Florida, the University of Louisiana at Lafayette and the College of William & Mary in Virginia.