Stories in Louisiana

Bad Water Out, Good Water In

Restoring water quality so that trees, plants and wildlife can thrive.

Aerial view looking straight down on a river meandering through a thick forest of bright green trees.
Atchafalaya Aerial An aerial photo from a drone of forested wetlands in the Atchafalaya River Basin © Joe Baustian/The Nature Conservancy

The Atchafalaya River Basin has been a conservation priority for The Nature Conservancy for many years. As the largest wetland and swamp in the United States, it represents a significant natural resource that impacts humans and wildlife from near and far. Protecting this irreplaceable landscape means working with all who depend on it to ensure its ecological health and productivity for future generations. 

TNC's Atchafalaya Basin Restoration Project (2:47) Lowering artificial banks and reconnecting the historic bayous.

Pulse of a River

Years in the making, TNC is embarking on a hydrological restoration project to reconnect the swamp forest located at our 5,000-acre Atchafalaya Preserve with the river. Since 2017, TNC has been moving through proper channels and teaming up with the State of Louisiana and other partners to develop this project that aims to modify portions of the federal floodway to support more natural water flows.

Currently the river’s course—which is mostly fast and straight due to years of manipulations—is diverted away from wetlands that are key to filtering water and trapping harmful pollution and sediment flowing downstream. In turn, these wetlands are cut off from the river’s ebbs and flows and subsequent oxygenation, required for healthy cypress trees, wild crawfish and other plants and animals characterizing this unique ecosystem.

Atchafalaya Basin Restoration


    Decades of dredging and other hydrologic manipulations have altered the Basin’s natural water flows, creating toxic pools of stagnant water called dead zones. Completely cut off from sources of flowing water, dead zones result in degraded water quality, reduced forest health and damaged habitat for wildlife.


  • Remove harmful dead zones by reinstating the historic north-to-south water flow pattern through the floodplain.

  • To do this, we shave down man-made spoil banks and establish drains through canal banks in the south, bringing good water in and pushing bad water out.

Map of bayou restoration in the Atchafalaya River Basin.
Map of Waterway Connection Reconnecting historical bayous in the north and establishing drains through canal banks in the south. © TNC

Benefits of Restoration

The Atchafalaya Restoration Project, which serves as a pilot, involves cutting small gaps in portions of levee banks to invite water into the swamp from the north and send it back to the river in the south. Allowing the water to move between the river and swamp, as nature intended, should yield significant benefits for water quality and wildlife habitat, as well as for recreation and commercial fishing. If successful, it could potentially guide actions in a broader system that drains two-thirds of the country.

Quote: Joe Baustian

Every day there are large- and smaller scale systems that control the flow and direction of the Atchafalaya River. In pursuing these manipulations, we’ve lost important connections between the river and surrounding floodplain.

TNC’s senior ecologist in Louisiana

Monitoring Results

How will we know if reinstating these natural processes are succeeding in rejuvenating this critically important landscape? Together with federal, state and academic partners, TNC has established a rigorous monitoring program charged with studying the project's effects on the ecosystem. Specifically, 15 monitoring stations have been set up throughout the swamp to observe and measure data, which has already indicated that reconnecting the swamps would improve water quality, enhance tree growth, and produce healthier and more numerous crawfish and fish.

A group of large cypress trees grow in a river in Louisiana.
Atchafalaya Afternoon light casts on cypress trees at Lake Martin in Breaux Bridge, Louisiana within the Atchafalaya Basin. TNC Louisiana works with community members in the Atchafalaya River Basin on efforts to conserve the region and provide economic stability. September, 2020. © Rory Doyle