Another project that is assumed to be on the landscape in FWOA is the River Reintroduction into Maurepas Swamp. This project includes a gated diversion structure in Reserve, Louisiana, and a conveyance channel crossing Highway 61 and Interstate 10 to allow a maximum of 2,000 cubic feet per second (cfs) of water from the Mississippi River to restore natural swamp hydrology and reduce salinity levels in the Maurepas Basin. Design of the River Reintroduction into Maurepas Swamp project is nearly complete, and construction is expected to begin in 2023, in coordination with the West Shore Lake Pontchartrain levee project.

Read more from the 2017 Coastal Master Plan

FY 2025 Status: In Construction
Funding Source: CWPPRA, State, RESTORE 
FY 2025 Expenditure: $41.4 million 
Estimate Cost: $330 million 

The Maurepas Swamp, located west of Lake Pontchartrain, was once naturally connected to the Mississippi River and received a steady freshwater input that maintained a healthy ecosystem. However, the river’s levees have disconnected the swamp, leading to degradation, diminishing fish and wildlife populations, and decreased plant life where trees once thrived. The river reintroduction will divert some freshwater flow from the Mississippi River back into the swamp, reconnecting it to the vital source and nutrients that once supported it. Once complete, the freshwater diversion will restore the natural swamp hydrology, providing wildlife and vegetation with the nutrients necessary to thrive. The project will benefit more than 45,000 acres of coastal marsh, forests, and wetlands in Ascension, Livingston, St. James, and St. John the Baptist Parishes.

Read more from the 2024 Annual Plan Project Highlights

Graphic by SCAPE, Published in 2023 Coastal Master Plan

Diversions mimic nature’s historic land-building processes by using the power of the river to move sediment and fresh water from the river into nearby basins. This project type can not only build new land but also provide a sustainable source of sand and mud necessary to sustain and increase the health of existing wetlands over time. Sediment diversions can also re-establish or maintain the fresh end of the estuary, originally lost to saltwater intrusion, ensuring that the range of fresh to saltwater habitats that makes Louisiana’s estuaries so productive persists into the future. Sediment diversions also help sustain nearby marsh creation, barrier island and ridge restoration projects.

Other Diversion Projects

Mid-Barataria Sediment Diversion | Mid-Breton Sediment Diversion | Atchafalaya Diversions | Central Wetlands Marsh Creation and Diversion |  Manchac Landbridge Diversion | Three Mile Pass Marsh Creation and Hydrologic Restoration | Ama Diversion | Union Diversion

The Maurepas swamp is one of the largest forested wetlands in the nation and recognized as a continentally Important Bird Area because it supports extremely dense populations of Prothonotary Warblers and Northern Parulas, both migratory songbirds of conservation concern.  But populations of these swamp specialists have declined around 50% over the last 16 years. Studies by members of the Audubon Delta team, led by Erik Johnson has found that  the more stagnant the swamp is becoming, the less suitable the trees are for caterpillars, which means fewer swamp forest birds. The River Reintroduction into Maurepas Swamp project will benefit the swamp by reconnecting it with the river, minimizing further wetland loss and the conversion of swamps to marshes, as well as improving swamp hydrology, tree health and crucial wildlife habitat. Learn about other work the National Audubon Society is doing to protect Prothonotary Warblers: Saving Colombia’s Forests Is Crucial to Protect Prothonotary Warblers | Songbird migration study finds a tiny, vulnerable winter range

Community letter to Army Corps of Engineers:

“This option is a unique opportunity to leverage state and federal needs into one solution that will nourish one of our region’s most valued resources,” said St. John the Baptist Parish President Jaclyn Hotard, who also signed the letter. “The Maurepas Swamp enhances and protects St. John the Baptist Parish by serving as a crucial barrier to storm surge and helping to filter harmful pollutants from our waterways,” she added. “Ultimately, this project fulfills a multiple lines of defense strategy to build resilience for our citizens and for future generations of the state of Louisiana.”

“Maurepas swamp is a very unique forested wetland unlike any other. Formed by the Mississippi thousands of years ago the river got cut off for reasons of flood control by buildings the levees. The swamp took years to degrade to the point it is now,” said Warren Coco. “This will help the swamp by supplying needed nutrients.”