The Atchafalaya Basin: Driving Over the Swamp

You are about to drive over eighteen miles of swamp on a concrete bridge. The Atchafalaya Basin Bridge, also called the Louisiana Elevated Thruway, is among the longest bridges over water in the United States. It was built in nineteen seventy-three and carries Interstate Ten across the Atchafalaya Basin, the largest river swamp in North America.

The basin is about one hundred fifty miles long and twenty miles wide, a braided network of bayous, lakes, cypress forests, and open water that functions as both the floodplain of the Atchafalaya River and the spillway for excess water from the Mississippi. The Chitimacha people have lived in this basin for thousands of years. They are one of the few Indigenous nations in the Southeast who still occupy a portion of their original homeland.

The Chitimacha Tribe of Louisiana holds federal recognition and maintains a reservation at Charenton, about forty miles southwest of where you are now. Their territory once extended across much of the coastal Louisiana plain. The basin underneath this bridge is alive in ways that are difficult to overstate: hundreds of species of fish, alligators, black bears, bald eagles, roseate spoonbills, nutria, enormous semi-aquatic rodents introduced from South America in the nineteen thirties for the fur trade, now naturalized beyond any possibility of removal.

The Corps of Engineers has spent decades managing the competition between the Atchafalaya and the Mississippi for water. The Atchafalaya wants to capture the Mississippi's flow, it is the shorter, steeper route to the Gulf. If that happened naturally, New Orleans and Baton Rouge would lose their access to the river.

The Old River Control Structure, about thirty miles north of here, is the engineering project that prevents it. The swamp below you is not passive landscape. It is a living argument between geology and infrastructure that the infrastructure is currently winning, at considerable effort.