Nearly 2 square miles of new marshland to be created with $176 million BP spill restoration money | Environment

Almost 2 square miles of new marsh will be built in the upper Barataria Basin in Jefferson Parish using sediment dredged from the Mississippi River just over 5 miles away, officials with the state Coastal Protection and Restoration Authority announced this week.

The new wetlands will be created about 15 miles south of New Orleans, just below the town of Jean Lafitte and the Pen, an area of open water resulting from a failed 19th century agricultural project. 

The $176 million project was approved in late July by the Louisiana Trustees Implementation Group, or TIG, which made up of representatives of federal and state agencies that oversee the spending of $5 billion of BP money dedicated to natural resource restoration in the state because of damages caused by the Deepwater Horizon oil spill.

The panel overseeing the use of BP oil spill damage money agreed last week to spend $25.6 million on three projects aimed at increasing oyster…

“The approval of this funding will enable the construction of one of the largest marsh-restoration projects in Louisiana history,” said Bren Haase, executive director of the CPRA, which serves as the lead trustee agency for Louisiana on the TIG, in a news release. “This massive marsh creation project will build upon previous investments by CPRA and its partners in the Bayou Dupont area and deliver tremendous environmental benefits to this region of Jefferson Parish.”

The National Oceanic and Atmospheric Administration served as the lead federal agency, overseeing the final restoration plan and environmental impact assessment.

The sediment will delivered though a pipeline that cuts across Plaquemines Parish into Jefferson from a location just north of the Phillips 66 Alliance Refinery. The pipe will be placed on a pathway running along new land built during earlier CPRA wetlands restoration projects in the Bayou Dupont corridor. 

Louisiana officials want to rebuild a broad bridge of wetlands and land across Plaquemines and Jefferson parishes to add habitat for fish and …

The project is the latest effort in a state strategy to use long-distance pipelines to create a land bridge south of populated areas of the west bank and its hurricane levees, with the new marshland both improving fisheries and wildlife and adding protection against hurricane storm surges. The wetlands of the Barataria Basin also suffered some of the worst damage from the BP spill, both as a result of operations to remove the oil and because of the effects of the oil itself on marsh grasses.

About 10.5 million cubic yards of sediment will be mined by dredge ships from deposits in the Mississippi River at the Alliance anchorage on the west side and from an area on the east side at Wills Point where sediment accumulates as a sand bar. That’s the equivalent of about 100,000 dump trucks full of dirt.

This map shows the depth of water above the Alliance anchorage in the Mississippi River, which will be mined for sediment to rebuild marshland…

Dredging the anchorage area will also help keep it deep enough to be used by oceangoing vessels.

Officials estimate that the two areas will be able to provide an initial 8.1 million cubic yards of sediment, and that during the project’s 26-month lifetime, enough additional sediment will be deposited in the two mining areas to provide the remaining 2.1 million cubic yards of material to finish the work.

This area along the east bank of the Mississippi River at Will’s Point will be mined for sediment for the marsh creation project.

Four-foot-high berms of material dredged from within the marsh creation areas will help hold the sediment pumped inland from the pipeline.

The plan is to fill each area to about 3 feet above sea level, and then to allow the ground to grow vegetation naturally with no manual planting.

The design calls for the marsh platform to be dry during periods of low water and to be flooded when the water level is high.

Gaps will be cut in the berms to allow for tidal exchange of water, sediments and nutrients and to provide access to the area inside by fish and wildlife.

The trustee group rejected two alternative marsh-creation proposals. One created less marsh, and the other required two construction phases, faced potential construction delays and was likely to cause more damage to nearby habitat from construction activities, said a report outlining the plan.

Also rejected was a so-called “natural recovery” plan, where nothing would be done to mitigate natural resources injured by the spill.

The five marsh creation areas are far enough north and west of the state’s proposed Mid-Barataria Sediment Diversion outfall area that they will not interfere with the movement of sediment released from the diversion, the project report said.

But they are close enough to receive enough sediment from the diversion to compensate for both sea-level rise and subsidence, the report said.

The sediment pipeline will likely require as many as three booster pumps to move the material from the river inland to the marsh creation areas. The pipeline will cross one canal containing two oil pipelines that are 5 to 10 feet below the pipeline channel. Pontoons on each side of the channel will keep the pipeline elevated during its construction.

Most of the new wetlands will be created within a large area of property owned by Louisiana Land and Exploration Company LLC, a subsidiary of ConocoPhillips, with some small portions owned by individual landowners.

Mark Schleifstein covers the environment and is a leader of the Louisiana Coastal Reporting Team for The Times-Picayune | The New Orleans Advocate. Email: [email protected]. Facebook: Mark Schleifstein and Louisiana Coastal Watch. Twitter: MSchleifstein.

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