Plaquemines protection plan
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Plaquemines Parish, a relatively thin strip of land that follows the Mississippi River to the Gulf of Mexico, needs protection from the type of devastation Hurricane Katrina unleashed upon it three years ago.
But building giant levees is not a realistic option. The sheer size of the structures would take a tremendous amount of money and land, notes Parish President Billy Nungesser.
So parish officials have decided to focus on natural protection such as barrier islands. forested wetland and ridges.
Building land in front of the existing protection system could reduce the size of the levees required to provide security and attract people to the parish again, Nungesser said.
“We’re never going to be able to continue to build levees and floodwalls if we don’t rebuild barrier islands,” he said.
Hurricane Katrina made first landfall in Louisiana near Buras, putting much of the parish under water for weeks.
About 29,000 people lived in Plaquemines Parish before Katrina. The latest U.S. Census population estimate was about 21,500 in July 2007, and Nungesser says about 24,000 live there now.
To protect the people who have returned and the investments companies are making in the area, Nungesser and others want to streamline some coastal land-building efforts.
“We’re talking about re-creating land of substance to protect against storm surge,” he said.
The parish is working with the U.S. Army Corps of Engineers on options including barrier island restoration, shoreline protection and rebuilding land that can be planted with trees.
The most cost-effective way of building land, Nungesser said, is using a resource the Mississippi River provides in abundance — dirt.
Parish officials want to dig “borrow pits” in several bends of the river where dirt, in the form of sediment, naturally falls out of the water. Pipelines would pump the sediment from the pits over the river levees to build land in adjacent areas.
“We just need to put those dredges out there and pump 10 to 12 feet and plant trees out there,” Nungesser said. “There’s no reason this can’t be done in a relatively short period of time.”
By building land through pipeline-sediment delivery, the parish will at the very least gain additional storm protection, Nungesser said.
The best-case scenario would be for the corps and the Federal Emergency Management Agency to take into account nonlevee hurricane protection when calculating flood risk, he said.
New FEMA flood-risk maps show that to be safe from storm surge, some houses must be raised up to 18 feet high. If the nonlevee protection is proven effective, can be quantified and is accepted by FEMA, there’s a possibility those height requirements could be lowered, said Joe Suhayda, an oceanographer working with the parish.
The parish will be paying for the start-up work on the projects. Officials then hope to leverage oil-and-gas revenue sharing with the state and federal governments to get the most funding possible, Nungesser said.
The parish is working with Coastal Environments Inc. and Suhayda to come up with the best land-building options.
P.J. Hahn, director of the Plaquemines Parish Coastal Zone Management department, said the parish has turned to dredge companies to discuss how to use sediment and dirt collected from the Mississippi River to build land.
“The dredge companies are the ones who know it can be done,” Hahn said.
South of Buras, barrier island restoration is a priority. Coupled with that effort is building up a section of a former natural ridge to provide a storm-surge barrier. Marsh land between the barrier islands and the western levees protecting Plaquemines Parish could then be restored, he said.
Most of the spots being considered for projects have been studied before through other coastal restoration programs.
Suhayda said tapping the Mississippi as a resource is natural for Plaquemines because the river runs straight through it.
If the land-building and freshwater-diversion projects being considered work in Plaquemines, he said, the methods could be adapted to areas of the state that lack easy access to a sediment-laden river.
“If you look at using natural processes, you really are talking about Plaquemines Parish,” Suhayda said.
Suhayda emphasized that the general approach is outlined in the state’s master plan.
“This is not a Plaquemines Parish plan. It’s an implementation of the state plan in Plaquemines Parish,” Suhayda said.
Garret Graves, director of the Governor’s Office of Coastal Activities, said it’s great to see a parish take action on hurricane protection and coastal restoration.
“They’ve talked to us about wanting to move forward aggressively,” Graves said.
He said that from what he’s heard so far, parish officials want to complement current efforts, not replace them.
He added that the state hasn’t seen any detailed description of proposed projects. But the overall philosophy of the parish is encouraging, he said.
During the next six months, the corps’ Engineer Research and Development Center will use computers to run a variety of scenarios, such as predicting what would happen if restoring a specific barrier island was coupled with marsh restoration in one area and ridgebuilding in another.
“Right now there are a number of projects that could be built in the next year or two,” Suhayda said.
Hahn said the parish government wants to move quickly and avoid overcomplicating something that’s technically simple.
“We’re not trying to build skyscrapers. We’re putting dirt in holes,” Hahn said.
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