Posted on July 25, 2022
Louisiana’s biggest coastal restoration project so far is complete, officials announced Thursday, bringing to an end more than two years of work to rebuild barrier islands in the Terrebonne Basin – using nearly enough sediment to fill the Superdome twice.
The three locations restored west of Port Fourchon will serve as speed bumps for hurricanes as well as turn back the clock to what existed before erosion and subsidence whittled them away. The cost was $166 million, paid for with proceeds from settlements over the 2010 BP Deepwater Horizon oil spill.
The project by the state Coastal Protection and Restoration Authority restored more than 1,000 acres, as well as 8.6 linear miles of beach. While it’s the biggest such project by acreage so far to be completed, it will soon be surpassed by others in the works.
Viewed from above, the new sediment sweeps out from green marsh, waves moving in from the Gulf lapping against it all. From that vantage point, the islands’ role as the state’s first line of defense against storms is strikingly clear, as is the extent of land loss over the decades, with vast stretches of open water where marsh once stood.
“The more land I have between me, wherever I’m standing, and the Gulf of Mexico as a hurricane is approaching, the better I feel, the better off we are,” said authority executive director Bren Haase. “Those natural barriers are very, very important. Forest, marshes, shallow bays and certain barrier islands are a part of that.”
The project and others like it are part of the state’s vital fight against land loss, caused largely by human activity, such as the levee system to prevent Mississippi River flooding and oil and gas exploration. Sea-level rise exacerbated by climate change is greatly intensifying the threat, with water levels along Louisiana’s coast potentially increasing by more than 4 feet by the end of the century. Beyond that, climate change is helping intensify hurricanes, which also take a toll on coastal land.
The CPRA is attacking the problem with a $50 billion, 50-year master plan – and it is facing long odds in its fight. Its projects are generally meant to last two decades, though design improvements may see some last far longer. Either way, erosion and subsidence will affect the restored islands just as they did the previous ones.
In search of long-term solutions, the authority is planning two unprecedented sediment diversions from the Mississippi River in the years ahead that will mimic the natural processes that built the state in the first place. Its coastal work is intended to function in tandem with levee building and other flood-protection projects.
Thursday’s announcement involved West Belle Headland, next to Port Fourchon, along with Timbalier Island and Trinity-East Island to the west. Sand for the huge operation was dredged from a nearby offshore site known as Ship Shoal.
The work was complicated by the busy 2020 hurricane season as well as last year’s Hurricane Ida, which roared ashore in roughly the same location, said project manager April Newman.
One of the islands – Trinity-East Island – was already completed by that time, and Haase said it held up well to Ida’s Category 4 winds. West Belle, which was still under construction and faced Ida’s full force, was not as lucky and saw setbacks, he said.
A project that will soon surpass the Terrebonne barrier islands in scale will be ridge and marsh creation work underway at Spanish Pass extending west from Venice. That project will cover 1,670 acres and is expected to be completed around January.
Kristi Trail, executive director of the Pontchartrain Conservancy nonprofit, said the Terrebonne project and others like it illustrate the state’s and her organization’s pursuit of multiple lines of defense against storms.
“This strategy shows how natural features of our coast, like barrier islands, marshes and ridges, complement manmade features like levees to protect us from storms,” she said. “The tragedies of Hurricanes Katrina and Rita in 2005 revealed to the world the enormous challenge Louisiana faces.”