Southeastern Louisiana is vanishing.
Two thousand square miles of wetlands have already been submerged in the Gulf of Mexico, and the state’s shoreline is receding quicker than anywhere else on Earth. A chunk of marshland as big as a football field washes away every hour — meaning that 16 square miles are erased from the map every year. Much depends on the Bayou State’s changing contours not only for the 1.2 million residents of greater New Orleans, threatened by violent storm surges, but for the entire country: half of the nation’s oil refineries, the mainland’s largest commercial fishery and the Western Hemisphere’s largest port all hinge on the region’s viability.
In response, Louisiana is implementing a $50 billion plan to save its coastline over the next half-century. Some call it ambitious; the rest say it’s a “moon shot.” But it’s the state’s only chance to reverse a manmade environmental catastrophe before it’s too late, says a two–part series by ProPublica and The Lens.
“What we had here was a paradise — a natural paradise,” Lloyd Sergine remembers. He’s describing the swamp village of fishermen, trappers and farmers where he grew up, just a couple dozen miles south of the Big Easy. “But when I try to tell the young people about this, they just stare at me like I’m crazy. They just can’t imagine what was here such a short time ago. And now it’s gone. Just gone.” When Sergine looks out onto the fields of his childhood, he sees only saltwater drowning the landscape. Derelict boats and ice chests float in on a high tide that soon washes over concrete foundations and wooden pilings where his neighborhood once thrived. “Everything we had was based on the wetlands,” he says. “When the wetlands started going, we were done for.”
At the heart of Louisiana’s Master Plan for the Coast is the restoration of the Mississippi Rivers’s natural process of depositing sand and mud along the delta, sediment that built up extensive wetlands over several thousand years. The mighty river once picked up 400 million metric tons of sediment before spitting the brown water into an ecosystem that depended on silt to avoid sinking into the ocean.
But after engineers attempted to limit the river’s devastating floods by constructing a network of dams, levees and dikes, annual sediment deposit dropped by 60 percent. Around the same time, in the 1930s, oil drilling and dredging of canals cut into the swamps. Deterioration accelerated as saltwater intrusion choked freshwater plants that had held the ground together and powerful hurricanes battered the vulnerable clumps of land.
Louisiana’s short-term fix is pumping sediment back into the crumbling marshes. Pipelines collect sand and mud from the riverbed and from offshore to add to flooded basins and to create new barrier islands. So far, at a cost of $105 million, two projects have restored 1,600 acres. But those gains are small compared to rapid loss: the same amount is being swept away every two months.
A long-term solution will require mimicking the Mississippi’s historical flow by diverting water in controlled surges. In an unprecedented experiment, the plan suggests building a system of gates that will open when the river runs high, flooding the area and restoring much-needed silt. “The one advantage this delta has over the many others that are in trouble is that we still have a river delivering the material to help get us out of trouble,” Denise Reed, chief scientist at the Water Institute of the Gulf, explains. “As long as that river is bringing the sediments to us, we have a chance.”
There’s still many unanswered questions for the project’s researchers and engineers. “Their solutions must fit within constraints imposed by how much sediment the river can deliver and must anticipate future sea-level rise and land subsidence. Somehow, they must balance the need for restoration with the needs of the shipping, energy and fishing industries,” Bob Marshall, of The Lens, writes.
Replicating North America’s largest drainage system will be no easy task, but the state thinks they can catch up by 2042.