Louisiana’s Most Ambitious Coastal Restoration Project Finally Takes Off

By redirecting Mississippi River sediment, the Mid-Barataria Sediment Diversion will combat the state’s land-loss crisis.
Roseate Spoonbill. Photo: Bill Dix/Audubon Photography Awards

After more than 15 years of research, engineering, and public engagement, the State of Louisiana broke ground this week on the Mid-Barataria Sediment Diversion, the single-largest ecosystem restoration project in the United States. One of the most heavily studied and modeled projects in Louisiana’s history, this project is a keystone of Louisiana’s $50 billion Coastal Master Plan, as well as Audubon’s vision for restoring the Gulf Coast following the BP oil spill.

Louisiana’s coastline is vanishing at an alarming rate. Since the 1930s, Louisiana has lost more than 2,000 square miles of coastal wetlands—that’s roughly the size of Delaware—due to several human-made and natural factors, such as leveeing the Mississippi River, erosion, and sea-level rise.

Barataria Basin, just south of New Orleans on the western side of the Mississippi River, is a large complex of wetlands that is experiencing some of the highest rates of land loss in the country. Without action, the Basin will lose an extreme amount of land—550 square miles over the next 50 years. Already, wetlands are eroding and converting into open water, while barrier islands further down the coast wash away, and communities nearby are vulnerable to storm surge and flooding.

Green marshes speckle a watery landscape that stretches out toward the horizon.

Louisiana's wetlands were historically built by the Mississippi River’s nutrient-rich sediment. During spring floods, the river would overtop its banks and provide a fresh layer of sediment to the wetlands nearby, anchoring the vegetation and providing habitat for a multitude of birds, fish, and other wildlife in this rich ecosystem. However, the federal government leveed the Mississippi River following the devastating 1927 floods, closing distributary channels and pinning the river in place. Since then, the river’s sediment has largely been wasted, funneled out to the Gulf of Mexico while , Louisiana’s once-vibrant coastal wetlands have withered for nearly a century.

To solve this land loss crisis, Louisiana has taken an innovative approach to build wetlands: a river diversion designed to mimic the natural processes that built the Mississippi River Delta in the first place. This project will essentially construct a permeable gate in the river levee that allows sediment to pass through when the river water and sediment is at its highest, directing that much-needed sediment to the starving wetlands in the Barataria Basin.

The Mid-Barataria Sediment Diversion has been designed to build land by using the natural energy of the river to capture and move sediment from upriver into adjacent degraded wetlands. By reconnecting the river to the wetlands, sediment and freshwater from the river will build and maintain up to 40 square miles of land in the Barataria Basin over the next 50 years.

Conceptual design of the Mid-Barataria Sediment Diversion. Video: Louisiana Coastal Protection and Restoration Authority

This new land will help iconic birds in Louisiana like Roseate Spoonbills and Bald Eagles, which depend on healthy, productive freshwater ecosystems to thrive. Since leveeing of the Mississippi River, the Barataria Basin has become saltier, causing these freshwater species to lose important habitat.

In fact, a recent Audubon Delta study found that changes to our coastal wetlands, such as the loss of forested wetland habitat, may have a noticeable negative impact on Bald Eagle populations. However, the study also shows that coastal restoration projects like the Mid-Barataria Sediment Diversions will freshen the upper estuary, creating more healthy habitat for the eagle to nest and forage. 

This pivotal project will build more wetlands than any other individual restoration project in the world and is the best solution to meet the challenges the state faces from land loss and a changing climate. The land loss crisis in Louisiana may seem insurmountable, but the creation of the Mid-Barataria Sediment Diversion proves that with top-tier science and engineering, as well as long-term commitment to conservation and advocacy on the Gulf Coast, we can turn the tide on coastal land loss.