Old River Control Structure
The Old River Control Structure is a floodgate system located along the west bank of the Mississippi River at river mile 315[1] in northern Louisiana, at the divergence of the Atchafalaya River. Completed in 1963, the complex was built by the U.S. Army Corps of Engineers to regulate water flow from the Mississippi into the Atchafalaya because of the increasing quantities of water that would otherwise flow into the Atchafalaya, due to that river's shorter and increasingly steeper course to the Gulf of Mexico. Generally, the water distribution between the two rivers is now maintained at 70% to the Mississippi, and 30% to the Atchafalaya.[2][3]
The Old River Control Structure is necessary to prevent the Atchafalaya River from capturing the main flow of the Mississippi, through the process of "avulsion," also known as "delta switching." If the Mississippi diverts it main channel to the Atchafalaya Basin and the Atchafalaya River, it would develop a new delta south of Morgan City in southern Louisiana, and water flow to its present channel through Baton Rouge and New Orleans to its current delta in southeastern Louisiana would be greatly reduced. Some researchers believe that natural processes increase the likelihood of this event each year, despite the present artificial control efforts.[4] The economic consequences are further described on the wiki page for the Morganza Spillway.
The possibility of such avulsion has become a concern during the 2011 Mississippi River floods, with opening of the nearby Morganza Spillway being considered if needed to reduce stress on various levees and other flood-control structures, including the Old River Control Structure.[5][6] Jeff Masters of the Weather Underground noted that failure of that complex "would be a serious blow to the U.S. economy, and the great Mississippi flood of 2011 will give [this structure] its most severe test ever."[7]
See also
- Lower Mississippi
- Morganza Spillway
- Atchafalaya River
- Atchafalaya Basin
- 2011 Mississippi River floods
- The "Atchafalaya" section of the book The Control of Nature by John McPhee.
References
External links
- John McPhee: Atchafalaya In: The New Yorker, February 23, 1987. Abgerufen im 9 May 2011 (Section of The Control of Nature.)
- Information, photos, diagrams
- History, information
- History, maps
- Interactive and zoomable map or satellite photos
- ↑ Vorlage:Convert up the river from Head of Passes, where the river's main stem breaks into three branches that soon flow into the Gulf of Mexico.
- ↑ McPhee, John: The Control of Nature. 1st Edition Auflage. Farrar, Straus and Giroux, 1989, ISBN 0-374-12890-1, S. 272pp.
- ↑ Angert, Joe and Isaac: Old River Control. In: The Mighty Mississippi River. Abgerufen am 30. Januar 2009. (Seite nicht mehr abrufbar, festgestellt im Oktober 2010.). Includes good map and pictures.
- ↑ Ronald Joel Daniels: On Risk and Disaster: Lessons from Hurricane Katrina. University of Pennsylvania Press, 2006, S. 45.
- ↑ Mark Schliefstein: Record high river likely to require opening of Morganza Spillway next week (May 4, 2011, revised May 9, 2011). The Times-Picayune (New Orleans), abgerufen am 10. Mai 2011.
- ↑ Mark Schliefstein: Morganza Spillway might be opened to ease swollen Mississippi River (May 8, 2011, revised May 9, 2011). The Times-Picayune (New Orleans), abgerufen am 10. Mai 2011.
- ↑ http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1798