Atchafalaya Basin

The Atchafalaya Basin exists on borrowed time — or, more precisely, on a federal permit to keep the Mississippi River from moving in. This south Louisiana floodplain covers about 1.4 million acres (5,700 km²) of bayous, cypress-tupelo forest and marsh, stretching some 150 miles (240 km) from the Old River area to the Gulf of Mexico. It is the largest river swamp in the United States. Because the Atchafalaya offers a shorter, steeper route to the sea, the Mississippi has been trying to shift into it for decades, and only engineering stops the switch.

That engineering is the Old River Control Structure, completed by the Army Corps of Engineers in 1963 and nearly undermined in the 1973 flood. By rule it sends about 30 percent of the combined flow of the Mississippi and Red rivers down the Atchafalaya, keeping the rest on course for Baton Rouge and New Orleans. The sediment it carries is building new land at the Atchafalaya and Wax Lake deltas while much of coastal Louisiana sinks. Cajun communities fish, hunt and harvest wild crawfish here, and drivers cross the basin on the 18.2-mile (29.3 km) Interstate 10 bridge. Congress designated the Atchafalaya National Heritage Area in 2006.

• Red River of the South
  Rust-colored border river between Texas and Oklahoma fed by
• The Mississippi River
  The great river that drains the American heartland fed by
• Gulf of Mexico (Gulf of America)
  The warm ocean basin that shapes America’s southern coast flows into
• Louisiana
  The Pelican State, where the Mississippi meets the Gulf located in
• Baton Rouge
  Capital of Louisiana, on the Mississippi River near