Old River Control Structure

The Old River Control Structure complex, showing the three dams at the outlet to the Atchafalaya River. View is to the east-southeast. Louisiana is on the right and the state of Mississippi on the left

The Old River Control Structure is an artifice built by the U.S. Army Corps of Engineers at the divergence of the Mississippi and Atchafalaya Rivers in order to maintain the water distribution between the two, at 70% and 30%, respectively. This was done in response to the increasing amounts of water flowing from the Mississippi into the Atchafalaya, due to the latter's shorter and increasingly steeper course to the Gulf of Mexico. The floodgate system was completed in 1963. The complex is located at river mile 315 on the lower Mississippi—315 miles (507 km) up the river from the Gulf of Mexico.

If allowed to flow freely, the Atchafalaya would capture the main flow of the Mississippi, forcing it to bypass its current path through Baton Rouge and New Orleans. The likelihood of this event increases each year.

The details of the Old River Control system are explored in the "Atchafalaya" section of the book The Control of Nature by John McPhee.

External links

• The Control of Nature reprinted in The New Yorker
• Information, photos, diagrams
• History, information
• History, maps

References

• McPhee, John (1989). The Control of Nature (1st Edition ed.). Farrar, Straus and Giroux. p. 272pp. ISBN 0-374-12890-1. {{cite book}}: |edition= has extra text (help); Unknown parameter |month= ignored (help)
• Angert, Joe and Isaac. "Old River Control". The Mighty Mississippi River. Retrieved January 30 2009. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |dateformat= ignored (help). Includes good map and pictures.