Posted on May 22, 2023
A bumpy, 20-minute ride on a Star Wars-like people mover crosses new land, the result of a nearly complete marsh creation project in an area that badly needs it.
The ride was part of a recent tour to showcase the Upper Barataria Marsh Creation project, built by pumping sediment nearly 14 miles inland from the Mississippi River.
Paid for with more than $181 million from the $5 billion set aside by BP to restore natural resources damaged during the company’s 2010 Deepwater Horizon accident and oil spill, the project overseen by NOAA Fisheries will have built close to 1,200 acres of new land when it is completed in October.
Some of the large polygons of new land already are covered with marsh grasses, while others are still a collection of brown, sandy patches, awaiting seeding by workers or by the natural spread of wetland vegetation.
The sediment pumped from the River filled open water to an initial height of about 3 feet above sea level, and the new land will eventually settle to about 1.5 feet above the water.
Already, the patches are attracting a variety of wetland birds, including killdeer, red-winged blackbirds, least terns, egrets and blue herons, and even an osprey.
Just offshore of one polygon, an alligator floated in a stretch of remaining open water.
The new land represents the fifth of a series of restoration projects dating back to 2009 that are rebuilding a landbridge across portions of Plaquemines and Jefferson parishes. They stretch from the unprotected side of hurricane levees along the River near the Phillips 66 Alliance Refinery to the Barataria Waterway just south of “The Pen,” a failed agricultural development that subsided and eroded into a 4,000-acre lake, and just south of the towns of Jean Lafitte and Crown Point.
The combined efforts are aimed in part at both restoring a small part of the more than 430 square miles of land lost in the Barataria Basin since the 1930s, one of the highest rates of land loss in the state, and staving off future wetland losses resulting from sea level rise driven by climate change.
“This landbridge is critical for separating the saltier lower part of the basin from the freshwater wetlands in the upper basin,” said Alisha Renfro, a coastal scientist with the National Wildlife Federation. “This helps keep those upper basin wetlands intact, providing habitat and storm surge protection for nearby communities.”
“The project will restore interspersed yet ecologically connected coastal habitats in the upper Barataria Basin, resulting in a larger and more stable marsh platform, restored fish and wildlife habitat, and reduced erosion and land loss in the basin,” said Donna Rogers, NOAA project manager for the restoration effort. “The new habitat will support diverse species of fish and wildlife — including many species important to Louisiana’s fishing economy.”
State officials say additional land will also provide some protection to locations to its north from surges of water from smaller storms, simply through the expansion of land in the area. As such, it will complement the construction of the new Upper Barataria hurricane levee system that runs through portions of St. Charles and Lafourche parishes to the west of the project.
Officials estimated that about 140 people have been hired to complete the project.
During the recent tour, a large bucket shovel excavator mounted atop a tracked vehicle was creating a 3-foot-deep waterway between two of the new land segments, which will allow water to flow between adjacent open water areas, and provide access for fisheries, said Jonathan Hird, a vice president with Moffatt & Nichol, which did design work for the project.
“There are two ways you could do that,” Hird said as he watched the shovel dig black muck out of the new pathway and dump it on the new waterway bank. “You can build a containment on either side, which is tricky, or you can just pump sediment across the area, let it settle for a bit, and then just dig it out, which is what we’re doing.”
Rogers said the interior waterway also will help funnel water and sediment into the new wetlands from the Mid-Barataria Sediment Diversion when it is built. Officials hope sediment from the diversion funneled from the River will find its way atop the new land segments over time, extending their life beyond their expected 20-year lifetime.
The Louisiana Trustee Implementation Group, representatives of federal and state agencies that oversee use of the BP money, expects ongoing subsidence and increased rates of sea level rise to reduce the land created by the project from its expected completed size of about 1,200 acres to only 826 acres at the end of 20 years, unless the diversion’s sediment slows those losses, or other actions — such as pumping in more sediment from the Mississippi River — are taken.
Weeks Marine mined 8.4 million cubic yards of sediment — nearly enough to fill the Caesars Superdome twice — from several locations on the Mississippi River just north of the Alliance Refinery.
The sediment was dredged from areas alongside the Mississippi River and pumped by pipelines as much as four miles to the river’s west bank near the refinery, where the official pipeline for the project begins. The sediment then travels another 13 ½ miles by pipeline to the project location. Crews build temporary berms around the edges of where polygons of new land will be created, and then the pipeline’s outfall sprays the sediment into open water until sand rises above the surface.
Heavy equipment then reworks the material to give it a proper shape to be quickly repopulated with vegetation. One of the polygons also was built to include a tidal pond.
NOAA will monitor the new land to insure the new marsh platform is delivering its environmental promises in terms of biomass needed to assure the land stays in place.
Monitoring also will be conducted from the end of 2024, after the project is completed, through the end of 2044, its official 20-year lifetime, to determine whether the expected variety of wildlife species are present, including brown and white shrimp, Gulf killifish, and blue crab on the marsh edge, marsh platform, tidal channels and tidal ponds, and that red drum are present in the project area.
The monitoring will include a review to determine whether the project is meeting various goals for different species.
They include increasing the abundance of blue crab to as much as six times that of other sites being monitored by the Louisiana Department of Wildlife and Fisheries, ensuring white and brown shrimp are 1.5 to 2.7 times more abundant in the project area than in other locations, and that red drum are present. The total marsh platform area also should not exhibit a higher erosion rate than a “reference marsh” at the end of its 20-year lifetime.