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Work Helps Save Barrier Island From the Brink

Wed December 05, 2007 - Southeast Edition

RACCOON ISLAND, La. (AP) Bamboo poles and PVC pipes jut from the sandy beach of Raccoon Island. Months and years ago, many of them helped mark the water’s edge to conservation agents who were desperately watching the island erode away.

“At one point, Raccoon Island was huge, almost 6,000 acres,” said Loland Broussard, a project manager with the U.S. Natural Resources Conservation Service.

Now, just 400 acres of the sandy ridge clings to the edge of the Gulf of Mexico. Raccoon, Whiskey, Trinity and East islands make up the rapidly eroding Isles Dernieres chain, Terrebonne’s once-robust coastal shield against the Gulf’s surging waters.

But on Raccoon Island, a controversial breakwater-demonstration project paid for with $10.6 million in federal Coastal Wetlands Planning, Protection and Restoration, or CWPPRA, money is raising hopes with some federal conservationists.

The Conservation Service and the state Department of Natural Resources proposed building 13 rock breakwaters, or walls, running parallel to the island’s shore to break waves before they reached the beach in hopes that would curb erosion and allow sediment to settle on Raccoon Island.

The project was authorized in 2002, and officials estimate it has created 16 acres (6.5 ha) of new land on Raccoon Island. It is being completed by Choctaw Transportation and its subcontractor, Bertucci Contractors Inc.

Raccoon Island is favored by coastal advocates because it houses the largest population of brown pelicans off the coast of Louisiana, with nearly 3,600 hatching this year.

Broussard gestured to a marker planted just two months ago near a rock groin, a jetty-like structure extending from the island’s shore to the first breakwater several yards off the island’s shore to cut off currents from sweeping past the rock banks.

“This was a surprise to us,” Broussard said, gesturing to nearly 65 ft. (20 m) of new sediment that has piled up along the groin since its construction. “That’s unbelievable. There’s even more here today than there was two weeks ago.”

The deposits have been so numerous that soon they might even fill in the space between the breakwaters and the island. Looking something like a sandy tiara, sediment has built up into small peninsulas scientists call “tombolos” connecting the island to each breakwater by a strip of beach.

Kevin Norton, state conservationist with the Natural Resources Conservation Service, said there were a lot of naysayers when the idea was initially pitched. Critics said building the rock structures was unnatural and wondered whether there was even enough sediment flowing through the island system to sustain growth on the chain.

“The corps issued this project on the condition that we constructed the first set of eight breakers, and if they worked, then we could build the next eight,” Norton said. “Well, they worked, and better than we could have ever planned.”

One of the reasons such rapid growth might be occurring is because Raccoon is the last island in chain, and the materials that get swept off other barrier islands farther east most likely get caught there.

That includes dredged materials that have been placed on East Island and Whiskey Island in hopes of beating erosion there.

“I tell them to keep on dredging,” Broussard said with a laugh.

The federal agency must continue monitoring the project for one year now that the breakwaters are complete to make sure they don’t redirect currents around the island to erode the west end.

That side of the island is especially vulnerable because during Hurricane Andrew in 1992, a couple of large channels formed and split Raccoon Island in two. They were later filled in.

Norton said there has been no erosion witnessed on the west end of the island so far; project managers have only seen gains.

They hope to launch Phase B, which will build 60 acres (24.3 ha) of marshland on the protected inner shore of the barrier island, next year.

“CWPPRA provides a critical part of the answer to the larger question of coastal erosion,” said U.S. Army Corps of Engineers New Orleans District Col. Alvin Lee, speaking at a dedication of Raccoon Island and five other projects on Oct. 26 at the LUMCON marine-research center in Cocodrie.

“This degradation of our barrier-island system has been going on since the 1800s. It’s encouraging to see these projects wrapped and working. We’ll be reassessing and looking at some of the rest of these projects that are still on the list,” he added.

Other CWPPRA projects dedicated in October include:

• The New Cut dune and marsh-restoration project, which closed the breach between Trinity and East islands by creating 8,000 ft. (2,400 m) of beach and dunes with dredged soil and plantings of nine species of native plants. Also installed was 17,000 ft. (5,200 m) of fencing to keep the sand in place. The total project costs will add up to $12.3 million, and 102 acres (41 ha) of land were created.

• The North Lake Mechant landbridge restoration project is under construction. It will use dredged soil to maintain the Small Bayou la Pointe natural levee ridge and the north shore of Lake Merchant in Terrebonne Parish, along with construction of sheetpile and rock to close off channels cut through the ridge and lake rim. The project will cost $31 million and is expected to create 604 acres (244 ha) of land.

• A Terrebonne Bay shore-protection project devotes $2.6 million to testing alternative shoreline-rebuilding projects, such as artificial oyster reefs.

• The west Lake Boudreaux shoreline-protection and marsh-creation project will build 13,000 ft. (3,960 m) of rock dike along three sections of the western shoreline of Lake Boudreaux, with several small dips to allow nutrients and organisms to travel between the marsh and the lake’s main body. It will offer storm protection to communities in the Grand Caillou area to the tune of $17.5 million and will benefit 277 (112 ha) acres of land.

• “The Jaws” is the name granted to 40,000 ft. (12,000 m) of earthen terraces constructed in West Cote Blanche Bay in Jefferson Parish. They are created with dredged materials that will trap sediment to naturally encourage wetlands to re-grow and reduce wind and wave energy. The project costs $3.9 million and will eventually benefit 1,999 acres (809 ha) of land in Jefferson Parish.

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