
Project reconnects the Mississippi River to the Maurepas Swamp and will revitalize over 45,000 acres
Louisianans generally think of coastal restoration as rebuilding barrier islands, reconstructing marshes adjacent to the Gulf of Mexico and large, sediment-delivering diversions below New Orleans.
Few realize the expansive cypress and tupelo swamps east and west of the Mississippi River below Baton Rouge are in the coastal zone as well and are also in desperate need of restoration efforts to stave off the same erosive factors of subsidence and saltwater intrusion that are killing wetlands closer to the Gulf.
Last December, Louisiana’s Coastal Protection and Restoration Authority (CPRA) broke ground on a small-scale diversion east of the river between Baton Rouge and New Orleans that has the potential to have a huge long-term impact.
The $330 million River Reintroduction into Maurepas Swamp project is a unique opportunity for the CPRA to expand coastal habitat restoration to include forested swamps, which provide as much storm protection and fishing and hunting opportunities as coastal marshes farther south.
Maurepas Swamp is a massive area of old-growth cypress-tupelo wetland that was once flooded annually by the Mississippi but was isolated by levees more than a century ago. The natural hydrology of the swamp has been interrupted by roadbeds and spoil banks from oil and gas canals as well, all leading to a slow death for the trees and the wildlife and fisheries production.
Fish and wildlife
Without the annual floods from the Mississippi River allowing sheet water to flow over the swamp, the native trees have lost a vital source of nutrients and fine sediments and the fish and wildlife have suffered. What could be a great fishery for largemouth bass, catfish, crawfish and sac-a-lait is only a marginal fishery that has declined steadily over the last half century and become increasingly vulnerable to hurricane-caused fish kills.
Broad areas of low-oxygen water filled with invasive vegetation, like water hyacinth and salvinia, have replaced healthy swamps full of native submerged vegetation and the oxygen-rich water needed to support healthy fisheries. The salvinia and lack of native food sources have also hampered what was once a world-class duck hunting area.
As trees have become unhealthy and die, the canopy has opened bringing in grasses and floating marshes that are much less stable than a swamp held together by healthy tree roots.
To bring back some of the nutrients and increase water health, the CPRA is building a structure in the Mississippi River Levee near Garyville that will flow water at 2,000 cubic feet per second through the swamp. Approximately 45,000 acres of imperiled swamp will slowly come back to life, limiting the saltwater intrusion brought by hurricanes and improving fisheries and wildlife habitat.
The bulk of the funding is coming from the RESTORE Council, a federal-state collaboration created by the 2012 law of the same name, which committed 80 percent of oil spill penalties back to the Gulf States to address habitat and economic damages. In February 2020, the RESTORE Council granted Louisiana $130 million for the Maurepas project and state officials have worked steadily to secure the rest of the funding, innovatively combining the construction of the diversion with features of the West Shore Lake Pontchartrain levee system to speed completion of both projects.
Maurepas Swamp WMA
An added benefit for hunters and anglers is that much of the positive impacts will be on public land managed by Louisiana’s Department of Wildlife and Fisheries. The Maurepas Swamp Wildlife Management Area is a massive 122,000-acre public hunting and fishing area, much of which is located within the diversion’s area of influence.
A 2013 settlement between MOEX, one of the owners of the Deepwater Horizon’s Macondo Well, and the U.S. Justice Department provided Louisiana with $6.75 million to add 11,145 acres to the WMA to preserve the coastal cypress-tupelo forest.
A public boat launch off Airline Hwy into the diversion’s conveyance canal will allow more access to the expansive management area. Project construction is expected to be complete by 2028.
Improving the health of the swamp will also increase its ability to help protect adjacent communities from hurricane winds and storm surges. The swamp stores storm surge waters during hurricanes. The diversion can also operate post-storm to push out higher salinity water and protect the trees and fish from long-term damage. The trees help to dampen wind, further protecting communities.
In all, the conservation of Maurepas Swamp using the restorative power of the Mississippi River may prove to be one of the wisest investments of oil spill penalties, especially given the long-term benefits to hunters, anglers and local communities. Allowing the swamp to continue to degrade would jeopardize the cultural value of fishing and hunting in the area and leave numerous towns in Southeast Louisiana more vulnerable to future hurricanes.