Mississippi mud may hold hope for Louisiana coast

July 14, 2017, Tulane University
Scene of Mississippi River. Credit: Jackson Hill

Many studies say capturing Mississippi River sand through diversions is key to rebuilding Louisiana's vanishing coast. But a new study in the open-access journal Earth Surface Dynamics of an old levee breach, or crevasse, along Bayou Lafourche indicates that mud, the most plentiful sediment type carried by the river, may be the most powerful tool in building land.

Researchers from Tulane University, Coastal Carolina University and The Water Institute of the Gulf found that retention of river diversion sediment in wetlands could be increased to more than 75 percent, if the outflow area is protected from waves and tides. Diversion sites on the open coast retain only 5 to 30 percent of incoming sediment.

By examining an old crevasse along Bayou Lafourche, a precursor of the Mississippi River, the researchers found that mud can build enough land to keep up with sea level rise if the diversion flows into existing vegetated areas protected from marine forces. This crevasse, located near Napoleonville, La., is mostly made of mud deposits that have remained stable enough over the centuries to support farming more than five miles from the Bayou Lafourche channel.

"Crevasse splays like this one are extremely common in the Mississippi River Delta and all of them consist mainly of mud," said Torbjörn Törnqvist, Vokes Geology Professor at Tulane University.

Since carried by Bayou Lafourche 1,200 to 600 years ago only contained about 20 percent sand, but an abundance of mud, the researchers suggest that land building can be maximized by gearing muddy diversions toward vegetated areas rather than to capture sandy deposits along the open waters of the Gulf of Mexico.

"These issues are not unique to the Mississippi River Delta," said report lead author Christopher Esposito, a research scientist at The Water Institute of the Gulf who undertook this study as part of his doctoral dissertation at Tulane University.

Explore further: NASA studies a rarity— growing Louisiana deltas

More information: Christopher R. Esposito et al. Efficient retention of mud drives land building on the Mississippi Delta plain, Earth Surface Dynamics (2017). DOI: 10.5194/esurf-5-387-2017

Related Stories

NASA studies a rarity— growing Louisiana deltas

February 9, 2017

The Louisiana coastline is sinking under the Gulf of Mexico at the rate of about one football field of land every hour (about 18 square miles of land lost in a year). But within this sinking region, two river deltas are growing. ...

Engineering a better future for the Mississippi Delta

April 28, 2015

River deltas, low-lying landforms that host critical and diverse ecosystems as well as high concentrations of human population, face an uncertain future. Even as some deltas experience decreased sediment supply from damming, ...

Mississippi diverted to revive Delta wetlands

June 9, 2011

Wetlands around the city of New Orleans are disappearing at such an alarming rate that a University of South Carolina coastal marine scientist predicts there will be little of the marshland left by the end of the century.

'Big Muddy' Missouri river needs a plan

July 11, 2017

As the Missouri River flows across the Great Plains to where it meets the Mississippi River at St. Louis, it accumulates such a large sediment load that it has earned the nickname "Big Muddy." A recent University of Illinois ...

Recommended for you

Study reveals properties of a Type Ib supernova in NGC 4080

March 25, 2019

A recent study conducted by astronomers has revealed important observational properties of a Type Ib supernova designated MASTER OT J120451.50+265946.6, which exploded in the galaxy NGC 4080. The research, presented in a ...

Catalyst advance removes pollutants at low temperatures

March 25, 2019

Researchers at Washington State University, University of New Mexico, Eindhoven University of Technology, and Pacific Northwest National Laboratory have developed a catalyst that can both withstand high temperatures and convert ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.