BELLE CHASSE, La. (AP) – Louisiana has completed one of its largest coastal restoration projects to date, and is at work on even bigger ones.
The dredge used to suck up sediment from the Gulf of Mexico to add 1,000 acres (405 hectares) of habitat to Terrebonne Basin sites is now hard at work in the Mississippi River, doing the same for 1,600 acres ( 650 hectares) project further east and named after a historic outlet in Plaquemines Parish called Spanish Pass, officials said last week.
“These are key examples of our front line defense” against hurricanes, said Bren Haase, executive director of the Coastal Preservation and Restoration Authority.
They had been eaten away by erosion and subsidence – and sea level risewhich, like hurricanes, is made worse by climate change.
On Tuesday, the authority announced the completion of another project – the addition of around 256 acres (104 hectares) of beach and dunes and 143 acres (58 hectares) of marshland on the island of West Grand Terre .
Barrier islands and marshes slow storm surges, so works protect people and buildings on the shore while providing habitat for plants and animals.
The Spanish Pass project begins just outside the parish town of Plaquemines in Venice.
The fragility of the wetlands lining the Louisiana coast was illustrated less than a minute by seaplane from the western end of the project. Here, the trees grow in parallel lines on relatively high ground in open water. They mark the banks of dredged canals in marshes that have now disappeared.
The state’s largest restoration project to date was a 1,200-acre (485-hectare) project completed in 2010 in the Upper Barataria Basin, authority deputy director Greg Grandy said in an email. . And work began in January on the nearly 2,800-acre (1,100-hectare) Lac Borgne Marsh Creation Project near Shell Beach in St. Bernard Parish.
“The more land I have between me, wherever I am, and the Gulf of Mexico as a hurricane approaches, the better I feel, the better off we are,” Haase said. “These natural barriers are very, very important.”
The Terrebonne Basin project increased the size of Timbalier and Trinity-East and West Belle Headland islands, as well as creating 8.6 miles (14 kilometers) of beach. It took about two years, partly because of the 2020 and 2021 hurricanes.
Hurricane Zeta in 2020 and Hurricane Ida last year both passed through the work area, Haase said.
He said the Trinity East Island expansion work was completed before Ida hit on August 29 and weathered the storm well. However, Ida damaged incomplete work on West Belle Headland – an area that was also worked in 2018 to repair damage from Hurricanes Katrina and Rita in 2005.
The dredge is now working to create seven miles of ridge-backed marshes in an area west of Venice. The ridges, high enough to be planted with trees, are designed both to protect the new marshes from erosion and to slow storm surges heading towards the shore.
The project will require 10.8 million cubic yards (8.3 million cubic meters) of sediment, enough to fill the Empire State Building nearly eight times.
The money paid by BP LLC after the 2010 oil spill finances ongoing projects.
The Terrebonne basin project cost $166 million. The Spanish Pass and West Belle Terre projects are around $100 million each, the Lac Borgne project is around $61 million.
The Barataria project, completed about a month before the spill, cost around $36 million.
Follow AP’s coverage of climate change and the environment: https://apnews.com/hub/climate-and-environment.