Efforts to halt Louisiana’s coastal erosion are entering promising new phase
BATON ROUGE, La. - Thousands of years ago, the Mississippi River Delta was formed from sediment deposited from the river. Layers upon layers of sand, silt and clay make up the land that millions of people live and work on today.
But in the past 100 years, Louisiana has lost over 2,000 square miles of land. That’s about the size of Delaware, or the total combined landmass of St. Charles, St. John, St. James, Ascension, East Baton Rouge and East Feliciana parishes.
Man-made levees protect South Louisiana from devastating flooding, but they also prevent the river from depositing sediment to maintain the marshes. Without major action, Louisiana would lose 4,200 square miles of land over the next 50 years, endangering communities and increasing storm surge.
But efforts to halt the erosion are entering a promising new phase over the next four years—one in which the state expects, for the first time since the losses began in the 1930s, to see more land created than it loses. That will come as the Coastal Protection and Restoration Authority (CPRA) shifts from planning massive new dredging and sediment-diversion projects to executing them.
“This is the moment in time in the coastal program that we have been waiting on,” said Chip Kline, the authority’s chairman. “We actually have the political will and the funding necessary to implement these projects that we’ve envisioned for years.”
The biggest is the Mid-Barataria Sediment Diversion project, which will help re-create marshes that will provide storm protection to Plaquemines, Jefferson, Orleans and Lafourche parishes.
The project will replace portions of the Mississippi River levee on the West Bank with large concrete gates that can be opened to allow sediment to flow from the river into depleting wetlands, creating tens of thousands of acres of new land.
The sediment from the river also will help sustain land that the CPRA is creating through dredging projects and extend the benefit from the dredging for 60 to 70 years.
“The Mid-Barataria Sediment Diversion Project is the cornerstone project within the coastal master plan on the restoration side,” Kline said. “It gives us a fighting chance to win this battle. It puts us in the ball game to save the Barataria Basin and portions of Southeast Louisiana because that project is designed to mimic the natural process that built this state to begin with.”
The project will eventually cost $1.4 billion, and much of it will be paid for from money provided by the BP oil company to cover damages from its oil spill in 2010.
Even though the project will harm some areas for harvesting oysters and brown shrimp, it also could provide a model for future sediment diversions along the Atchafalaya River and other points of the Mississippi.
Since the CPRA was formed in 2007 to centralize the state’s coastal environment efforts, it has secured over $21.4 billion for protection and restoration projects in 20 parishes. It has built or improved over 300 miles of levees and 60 miles of barrier islands and dredged over 150 million cubic yards of material, creating nearly 50,000 acres of new land.
Each year, the authority presents a plan to the Legislature outlining project timelines, anticipated costs and funding sources. The fiscal year 2022 plan includes 110 active projects, including nine in Southwest Louisiana, 35 in South Central Louisiana, and 66 in Southeast Louisiana. The authority anticipates over $887 million in investments in the coming year, with 90% of total expenditures going toward project construction and maintenance.
These projects fall into two basic groups— hurricane protection or risk reduction projects and restoration projects. On the restoration side, the overwhelming majority are dredging projects in which material is taken from the Mississippi River or the continental shelf and pumped into depleted marshes. The authority anticipates that these projects will create about 15,000 acres of new land.
Other projects include flood gates, surge protection, pump stations and barrier island restoration.
Although the Mid-Barataria Sediment Diversion Project is yet to be constructed, the key to years of careful planning and development is housed in Louisiana State University’s Center for River Studies.
The center uses its 10,000-square-foot model of the Lower Mississippi River to perform experiments that recreate the river flow, water levels and sediment travel at a rate of one year of real-life movement for every hour.
Director Clint Willson said that the work conducted at the center provides data that is crucial for the operations of CPRA and the Army Corps of Engineers.
“With the model, we’re trying to help the state understand how the sand moves down the river year to year, decade to decade,” said Willson. “Then the state can think about how much sand is going to be available that they can either dredge and pump for marsh creation projects or how much sand will be available when they open the river sediment diversion gates.”
Kline said the model was “a game changer for us” in designing the Mid-Barataria Sediment Diversion Project.
“It’s an impressive structure, and its value cannot be put into words,” Kline said.
“Going into the future,” he added, “We plan on using that model to help inform the operations of that structure—when do we need to turn that structure on to capture the most sediment? What kind of flow do we need to operate the diversion?”
The work at the river studies center and the hundreds of coastal protection and restoration projects employed by the state all share a common goal—protect Louisiana residents, conserve the state’s coast and preserve Southern Louisiana’s cultural heritage.
As the marshland sinks, scientists project that sea levels will rise as a result of climate change, further complicating the task of saving the state’s coastline.
“I’m never going to say, ‘I’m just going to walk away because this is a losing battle,’” Kline said. “This is a battle that has got to be fought, now and into the future, to make sure that we continue to live and work in the place that is so unique known as South Louisiana.”
The coastal authority’s annual plan awaits approval from the House and Senate Natural Resources committees and the House and Senate Transportation, Highways and Public Works committees before a vote by the full House and Senate.
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