Just weeks away from pumping the last thousand cubic yards of material at the LaBranche Marsh Creation jobsite in Louisiana, Project Manager Charles Markham reflected on the team’s determination and hard work to finish the year-long project.
“The project team did a great job of keeping the ball rolling and meeting expectations for this project through communication and knowledge,” Charles explains. “It took a big effort to get us to this point.” Manson partnered with the Natural Resources Conservation Service (NRCS)—an agency of the United States Department of Agriculture (USDA)— to restore several marshes that make up the LaBranche Wetlands. The program aims to reverse wetland deterioration and loss of plant life following the construction of the Illinois Central Railroad— now Canadian National Railway (CN Rail)—and Interstate 10 (I-10), as well as decades of intense hurricanes, according to an NRCS report. “Due to the man-made structures and hurricanes in the last 80 years, the marshes have converted to open water,” says Project Engineer Jessica Heath. “Rebuilding these marshes will protect local populations, as well as benefit local wildlife.”
In efforts to revitalize the wetlands, Manson restored more than 1,500 acres of marsh by dredging and pumping material from a borrow site within Lake Pontchartrain to three marsh creation cells—one to the north and two to the south of I-10. The restoration will provide environmental benefits for local fisheries and birds, including great egrets and cranes, and will increase storm protection in the region—especially along I-10, which is the fourth-longest interstate in the U.S., providing passage from Arizona to Florida.
Setting boots on the ground at LaBranche, Charles, Jessica, Field Engineer Kalvin Lentz (who later transitioned to superintendent on the project), and Superintendent Kenneth Holston met with subcontractors Wilson Coastal Development, HydroTerra Technologies, and NOLA Boat Rentals to discuss the first phase of work and establish a collective buy-in of strategic communication between all parties involved.
“Communication was a big factor at the beginning of the project because the subcontractors were responsible for most of the onsite work,” Charles says. “The Manson team was actively managing all the moving parts of the job and touching base with team leaders to make sure they had what they needed to get the job done.”
Containing the Marsh Cells
To remove the open water areas from the three project sites and fill them to an appropriate elevation by pumping the dredge material, Wilson Coastal Development deployed several marsh buggies (amphibious excavators capable of working on land and in water) to excavate existing material while crews began building containment dikes (man-made ridges used to prevent water from entering and escaping a specific area) around the three marsh creation cells.
“The contract required us to construct containment dikes to section off the three cells,” Kalvin says. “The point of the dikes is to help hold back the slurry once we start pumping. It also allows the material to settle out of the water column before it drains from the cells through the weir boxes (equipment used to measure water-flow).”
For 10 months, crews constructed more than 54,000 linear feet of containment dikes in 2,000-ft sections around the three marsh areas, while excavation crews successfully dug in each cell.
To pull off each feature of work on a heavily active jobsite and to ensure team leads were on the same page, the project team held daily meetings to discuss concerns and timelines.
“The daily meetings were set up like an open forum for team leads to make suggestions on how to execute the work better,” Jessica explains. “It also provided an opportunity for the team to discuss their work plans for the day, the path going forward, and how they can work alongside one another to successfully complete all the features of work.”
Threading the Needle to Pump at LaBranche
After almost a year of dike construction and excavation, the team shifted their attention to the pipe laydown and dredge work. With much of the planning and proposed coordination completed during the construction and excavation phase, the project team mobilized the cutter suction dredge ROBERT M WHITE (R.M. WHITE) and marsh teams to begin the next phase in July 2024.
One major component the team heavily prepared for was identifying and locating the various utilities in the area that service I-10, CN Rail, and the surrounding populations.
“We spent some time talking with contacts from the railroad and local gas utility companies and also verified the locations of the utilities with our third-party surveyor, HydroTerra,” Kalvin says. “It’s important to ensure we do not have any conflicts with any utilities while laying the dredge pipe, which would cause environmental issues and would ultimately delay the project.”
Crews set up more than 40,000 ft of steel and plastic pipeline from the Lake Pontchartrain borrow site to the three marsh creation cells, with the single longest-length pipe measuring 24,000 ft.
One unique challenge during this process was the presence of a railroad bridge in the pipeline path. “We understood this was probably the biggest challenge we would face on this project because of the risk it presented,” Jessica says.
“Kalvin did a great job in researching the drawings of the railroad and guided the crew to getting the pipeline put in place underneath the bridge.” With everything in place, the R.M. WHITE anchored down at the borrow site in Lake Pontchartrain.
The R.M. WHITE dredged more than 6.2 million cubic yards of material to fill the three marsh creation cells, restoring the vast ecosystem that serves as home to regional wildlife and creating recreational water activities for locals.
“This project marks the biggest marsh creation job for Manson, with the last project completed over a decade ago with our old cutter suction dredge LEONARD J (sold in 2018),” Charles noted. “This is the first time the R.M. WHITE crew has completed a marsh creation job, and it is a milestone for the next generation of Manson who now have this experience under their belts.”
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