Plaquemines seeks optimum shoreline options

At first glance, it’s a typical south Louisiana marina, with boat slips, worn wooden docks and buildings perched high on pilings.

But the Buras marina in Plaquemines Parish also is a laboratory of sorts, a testing ground for methods to combat the erosion that is relentlessly erasing the coast.

Hay bales, oyster shells, berms fashioned from dredged dirt and submerged concrete structures are among the experiments aimed at seeing what can best hold the shoreline in place.

Plaquemines officials have about $3 million from the parish and the Coastal Impact Assistance Program to test those and other ideas for shoreline protection in their area.

Their goal is to find out what works, and what doesn’t.

The work going on at the marina in Buras is a small-scale example of what’s happening all over Plaquemines Parish these days, with a multitude of coastal-restoration projects either completed or under way to help protect levees that protect the parish.

“We’ve got a number of plates spinning right now,” said P.J. Hahn, administrator of the coastal zone management program for the parish.

And there’s a need. Standing on a boat looking toward the marina, Parish Councilman Byron Marinovich pointed to the open water that faces not only the marina but the protection levee near La. 23 as well.

“This all used to be land out here, but now it’s all gone,” he said, pointing to a GPS navigation screen that showed the boat sitting in the middle of a canal, surrounded by marsh. Looking up from the screen and out to the horizon, the only thing to be seen was the water being churned up by a small November storm.

“This was a canal,” Marinovich said. “It’s not anymore. It’s all gone.”

With additional money this year allocated to each council member to spend in their district, Marinovich decided he wanted to do one large project instead of a lot of small projects around his district, which includes Buras.

So the marina will become a sort of testing ground for ideas and products that companies promise will help keep the shoreline in place, break down waves that chip away at the coast or provide some storm protection.

“The big thing about this is we’re going to try to do this as a living laboratory,” Marinovich said. “We’re looking at everything, and we’re looking at combining things to see what works better.”

Hahn said many of the companies touting potential coastal-restoration answers are new and are looking for a chance to show off what they’ve got, meaning they’ll probably offer cheaper deals in exchange for a chance to prove the product’s worth.

“How do you know if it works or not unless you give them a shot at it?” Hahn said. “If it holds up after a hurricane here? Buy it.”

In addition, Marinovich said, unlike many of the restoration projects going on now, the projects at the marina are easily accessible by road and could give the parish a chance to showcase what’s being done.

In other parts of the parish, pipelines are delivering sediment from the Mississippi River to help rebuild marsh areas that have disappeared under the water over the years.

One is in the Lake Hermitage area west of the Mississippi River, where the sediment pumping continues to build land to help separate the lake from more open water to the south.

The parish is also moving forward with elements in its master plan that call for building ridges that will be planted with cypress trees on the water side of the parish levees. The plan is to then build marsh areas between these ridges and the levee.

The parish worked with the corps’ Engineer Research and Development Center and found that an eight-foot ridge was far more effective in knocking down storm surge than marsh grass. So they moved forward in looking at how to build ridges on the outside of the levee system to not only reduce storm surge but help protect the levees as well.

“All these environmental groups want to build marsh,” said Billy Nungesser, the Plaquemines Parish president. “We want to build eight-foot ridges with marsh behind it.”

Although there was initial pushback about building ridges and barrier islands to an elevation above a few feet, that has changed in recent years, and barrier islands are now built with dunes that can be much higher.

“When I first started this, I was told you’ll never get a coastal restoration project that is over three feet,” Nungesser said. However, he said, those lower elevation projects didn’t fare as well during storms. “We went out after Katrina and Rita and Gustav and Ike, and we couldn’t even find the projects we spent millions of dollars on,” he said.

All of this goes back to the concept of “multiple lines of defense,” based on the idea that having several obstructions between the open water of the Gulf of Mexico and on-shore communities will reduce the height of the storm surge.

Hurricane protection levees were built in south Louisiana at a time when there were miles of marsh between the levees and open water, and they weren’t designed to withstand direct wave impact during storms.

To complement these larger ridge-building projects, the parish has also used $8.9 million in Coastal Impact Assistance Program money to do seven smaller “fringe marsh” projects that will add smaller sections of land where possible. These projects were done at sites where canals that service marinas or other waterways needed to be dredged. The contractor used the sediment removed from the canals to create marsh areas along the outside of the canals.

The area still looks like it’s open water, but the water is really only an inch or so deep; the idea is that once wetland plants get established, the marsh will build up from there on its own.

“We’re trying a lot of different things down here. Just to see what works and what doesn’t work,” Hahn said.