Forest borders the brown waters of the Atchafalaya River Basin
Atchafalaya River Basin Forest borders the brown waters of the Atchafalaya River Basin © Audra Melton

Stories in Louisiana

The Atchafalaya River Basin

At almost a million acres, the Atchafalaya River Basin is North America's largest floodplain swamp.

America's Great Swamp Forest

The Nature Conservancy in Louisiana has identified the Atchafalaya River Basin as one of the state's most important natural habitats. And now, working with landowners and other partners, we're able to work to protect this unique landscape for people and nature for the first time in its history. Our 5,000-acre Atchafalaya Preserve will serve as a model from which we can develop a lasting restoration and conservation impact on this great swamp forest.

The Atchafalaya River is a distributary of the Mississippi River, and takes on about a third of the Mississippi’s water as it approaches the Gulf of Mexico. The Atchafalaya Basin’s deep woods, fertile marshes, and meandering waters provide essential habitat for more than 300 species of wildlife and 100 different aquatic species, as well as a rich diversity of native plants. Together, these lush habitats power the livelihoods and recreational activities that shape the region’s history, culture, and heritage.


Besides providing critical habitat, the Atchafalaya Basin functions as a flood relief outlet for the Mississippi River Basin by taking some its water. Another of the basin’s crucial functions is its filtration power. In many ways it functions as the kidneys of the Mississippi River—the meandering journey through the basin removes nutrients and improves water quality before its arrival in the Gulf of Mexico.

This delivery of fresh water to the coast creates unique wetland habitats that oysters and other aquatic species need to thrive. The Atchafalaya is growing the deltas in Atchafalaya Bay and Wax Lake by depositing sediment, representing the only instance of coastal land building in Louisiana.

The Atchafalaya contains an especially high variety of plants and wildlife that is not only important for nature's sake, but also to the people who make their living from the Atchafalaya's lands and waters.  In fact, the value of the Basin's natural services (flood control, carbon storage, navigation, oil and gas resources, forest, fish and wildlife resources, and nutrient reduction) is valued at billions of dollars annually. 

But the future of the Atchafalaya is at risk and has spurred an initiative to conserve and restore its resources.

Forest in the Atchafalaya River Basin
Great Swamp Forest Forest in the Atchafalaya River Basin © Audra Melton

The Challenge

The Atchafalaya River is heavily used for shipping and industry, and decades of hydrologic manipulations have altered water flows. Now, vast areas of backswamp floodplain have become disconnected from the river. High banks along the river and its smaller distributaries prevent the natural overflow of river water into the backswamp. Because of the faster, straighter flows, the water doesn’t have the time or space it needs to be filtered by the wetlands.

Throughout the Atchafalaya Basin, we’re seeing degraded water quality, reduced forest health, and damaged habitat for wildlife. In some places, water flows the wrong way, causing semi-permanent flooding that hurts forests. Other places suffer from too much or too little sediment delivered from the river, creating a land and waterscape fundamentally altered from how we first came to know it.

Three-Pillared Solution


Drawing on more than 60 years of experience and proven results, we will work to restore habitat for fish, wildlife, and other species that rely on the basin’s habitats for survival. A large part of these efforts will include restoring natural water flows for the benefit of both people and nature. TNC wants to reinstate the historic north to south water flow pattern through the floodplain through processes like restoring inputs and removing high spoil banks.


At The Nature Conservancy, science is at the heart of who we are and what we do. We are using science as a guide for our restoration efforts, learning as we go to ensure the long-term health of this important place. 

TNC has developed a rigorous monitoring program to measure current conditions, and will continue monitoring into the future to assess conditions after the restoration. This monitoring framework has been vetted by state, federal, and academic partners, and it includes strategies to modify restoration approaches as needed.

Through our Conservation Fellows Program, we are engaging graduate researchers in the Atchafalaya and throughout the Mississippi River Basin in order to understand the complex problems throughout the system and work toward solutions. By encouraging collaboration and communication, these future conservation leaders will think beyond a single problem.

An artist's rendition of the completed Atchafalaya Conservation Center barge, which is currently under construction.
Floating Conservation Center An artist's rendition of the completed Atchafalaya Conservation Center barge, which is currently under construction. © Jim Bergan/The Nature Conservancy


The Atchafalaya River Basin is the place where people have connected to nature for generations. With the preserve, TNC’s immediate presence will strengthen its connection to the local community and crawfishermen, which is crucial to effective conservation work in the area. Through our work, we seek to strengthen, elevate and sustain the community’s efforts to conserve this natural resource by working directly with local stakeholders.

The Nature Conservancy of Louisiana is breaking ground—or water, so to speak—on a research and education complex in the Atchafalaya River Basin. The Atchafalaya Conservation Center will feature two floating barges on the Little Tensas Bayou, with a pavilion and trail system on land. The development of this Conservation Center represents an extension of the investment in the Atchafalaya River Basin and its community by allowing for a more intimate approach to stewardship, monitoring and science-based restoration activities.

Bryan Piazza, the Louisiana Chapter’s Director of Freshwater & Marine Science, is excited to have this home base. “It means that when we’re talking about the Atchafalaya River Basin with students, scientists, whoever—we won’t be in our offices,” he says. “We’ll be here. When people can see what you’re talking about, it’s much more powerful.”