‘Pillows’ Provide a New Type of Coastal Protection for Louisiana

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Posted November 8, 2018

Along a 3-mile section of coastline in Southwestern Louisiana, a giant crane is dumping large rocks to cap a first-of-its-kind shoreline protection project.

The $34 million effort, funded through a state and federal task force, benefits the Rockefeller State Wildlife Refuge on the Gulf of Mexico. Donated to the state of Louisiana nearly a century ago by the heirs of John D. Rockefeller, the refuge originally encompassed 86,000 acres. The refuge, which like much of the coast suffers significant land loss, measures roughly 71,000 acres.

"I think Southwest Louisiana is a hidden gem," said Gabe Giffin, a spokesman for the refuge, which is administered by the Department of Wildlife and Fisheries.

Giffin said this pristine marsh southeast of Lake Charles makes for a critical piece of habitat, home to iconic Louisiana species and millions of migratory birds.

"On their way back up in the spring, this is the first little piece of land that they see," Giffin said.

While shoreline protection projects are fairly common along Louisiana’s coast, this one takes a new approach. An aggregate material, encased in the rocks, significantly lowers the weight of the material.

“We have really high compressible soils in this area," said Bevin Barringer, project manager for the Louisiana Coastal Protection and Restoration Authority. "So, reducing the overall weight was important to reduce the settlement.”

Simply rocking the coast is often not a solution, Barringer said, because in Louisiana’s soft soils, “you would have the rocks essentially disappearing over time.”

Rockefeller suffers some of the worst erosion along coastal Louisiana, ranging from 46 to nearly 250 feet per year. Visitors will find no white, sandy beach along the Gulf here. Waves push a sort of shell hash, which looks a bit like oat meal, onto marsh grass along the shoreline. As the grass dies, wave action devours the bare soil.

From a staging area a few miles away, the aggregate material is loaded into large sacks, or “pillows,” as project managers call them. In 70 feet of water, crews lay a bed of limestone to secure the pillows before covering them in a fabric and topping everything with rock.

“Our long-term objective is for the land to start building behind the breakwater, and eventually, ideally, get up to the breakwater,” Barringer said.

In the last few months, workers have installed the pillows along 2 of the 3 miles in the project area. Shane Acosta, one of the crew members for the contractor, Patriot Construction, said they have already noticed a difference.

“When you have 3-, 4-foot seas, the water behind the breakwater, it’s undisturbed,” Acosta said.

In this part of Louisiana, far removed from the Mississippi River, coastal restoration involves fewer options.

"We have no large, freshwater source bringing down sediment like that," Giffin said. "So, we have to look at alternative options."

That meant competing for several years with other projects statewide before convincing the board that administers the Coastal Wetlands Planning Protection and Restoration Act to fund the project.

Since the aggregate material weighs about half what an equal volume of rock would weigh, planners believe the process could have applications along other parts of Louisiana's rapidly-subsiding coast.

However, at roughly $10 million per mile, no one suggests this comes cheaply or that it could work everywhere along the state's roughly 7,700 linear miles of coastline.

“I think those are the crucial conversations all of us in Louisiana are going to have to have with each other,” Giffin said. “All of these projects cost millions of dollars.”

While the emphasis is often on restoration, refuge managers point out the project will prevent land loss.

“Not only are you stopping the rate of erosion, but you’re now protecting lands that have been there for centuries,” Giffin said.

Source: Fox8Live