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Old page wikitext, before the edit (old_wikitext) | '{{Short description|Floodgate system in Louisiana, USA}}
[[File:Old River Control Structure Complex.jpg|right|thumb|The Old River Control Structure complex. View is to the [[east-southeast]], looking downriver on the [[Mississippi River|Mississippi]], with the three [[dam]]s across channels leading to the [[Atchafalaya River]] to the right of the Mississippi. [[Concordia Parish, Louisiana]] is in the foreground, on the right, and [[Wilkinson County, Mississippi]], is in the background, across the Mississippi on the left.]]
[[File:Old River Control discharge.jpg|right|thumb|Old River low-sill control structure discharging water into the Atchafalaya, May 2011]]
The '''Old River Control Structure''' is a [[floodgate]] system in a branch of the [[Mississippi River]] in central [[Louisiana]]. It regulates the flow of water from the Mississippi into the [[Atchafalaya River]], thereby preventing the Mississippi River from changing course. Completed in 1963, the complex was built by the [[U.S. Army Corps of Engineers]] in a side channel of the Mississippi known as "Old River", between the Mississippi's current channel and the [[Atchafalaya Basin]], a former channel of the Mississippi.<ref>{{cite magazine |last=McPhee |first=John |title=The Control of Nature: Atchafalaya |magazine=The New Yorker |date=February 23, 1987 |url=http://www.newyorker.com/archive/1987/02/23/1987_02_23_039_TNY_CARDS_000347146 |access-date=May 12, 2011}} Republished in {{cite book |last=McPhee |first=John |title=The Control of Nature |publisher=Farrar, Straus and Giroux |year=1989 |isbn=978-0-374-12890-6}}</ref><ref>{{cite web | title=Old River Control | work=The Mighty Mississippi River | author=Angert, Joe and Isaac | url=http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-url=https://web.archive.org/web/20090515010700/http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-date=May 15, 2009 |access-date=2011-05-12}}. Includes map and pictures.</ref><ref name="AmericasWetlands"/><ref name="InteractiveMap" /><ref name="kemp">{{cite web |url=http://www.tulane.edu/~bfleury/envirobio/enviroweb/FloodControl.htm |title=The Mississippi Levee System and the Old River Control Structure |first=Katherine |last=Kemp |date=January 6, 2000}}</ref>
The Old River Control Structure is a complex containing the original low-sill<ref>{{Cite web | url=http://www.uoguelph.ca/geology/geol2250/glossary/HTML%20files/lowsillstructure.html | title=Low Sill Structure}}</ref> and overbank<ref>{{cite web|url=https://www.johnweeks.com/river_mississippi/pages/lmiss23.html|title=Old River Control Structure, Point Breeze, LA|website=www.johnweeks.com}}</ref> structures, as well as the auxiliary structure that was constructed after the low-sill structure was damaged during the [[Mississippi flood of 1973|Mississippi River Flood of 1973]]. The complex also contains a navigation lock and the Sidney A. Murray Jr. Hydroelectric Station.<ref name=Piazza2014>{{cite book |last=Piazza |first=Bryan P. |title=The Atchafalaya River Basin: History and Ecology of an American Wetland |year=2014 |publisher=Texas A&M University Press |isbn=978-1-62349-039-3}}</ref>
== Old River ==
[[File:Geomorphology of Old River.jpg|thumb|left|300 px|Formation of the Atchafalaya River and construction of the Old River Control Structure.]]
Before the 15th century, the [[Red River of the South|Red River]] and Mississippi River were entirely separate and flowed more or less parallel to one another.<ref name="AmericasWetlands">{{cite web |title=Louisiana Old River Control Structure and Mississippi river flood protection |url=http://www.americaswetlandresources.com/background_facts/detailedstory/LouisianaRiverControl.html |work=America's Wetland Resource Center |publisher=Loyola University's Center for Environmental Communication |access-date=2007-04-01 |archive-date=2016-03-10 |archive-url=https://web.archive.org/web/20160310124727/http://www.americaswetlandresources.com/background_facts/detailedstory/LouisianaRiverControl.html |url-status=dead }}</ref> Beginning in the 15th century, the Mississippi River created a small, westward, [[meander|oxbow loop]], later called Turnbull's Bend, near present-day [[Angola, Louisiana]]. This loop eventually intersected the Red River, making the downstream part of the Red River a distributary of the Mississippi; this distributary came to be called the [[Atchafalaya River]].<ref name="AmericasWetlands" />
In the heyday of [[steamboat]]s along the Mississippi River, such a vessel would need several hours to travel the {{convert|20|mi|km}} of Turnbull's Bend, after which it would have progressed only about {{convert|1|mi|km}} from the entrance to the bend. To reduce travel time, Captain [[Henry Miller Shreve|Henry M. Shreve]], a river engineer and namesake of [[Shreveport, Louisiana|Shreveport]], Louisiana, dug a canal in 1831 through the neck of Turnbull's Bend; this canal became known as Shreve's Cut. At the next high water, the Mississippi roared through this channel.<ref name="nytimes">{{cite news |url=https://www.nytimes.com/1987/05/03/us/612487.html |title=$500 Million (and Rising) to Contain a River |date=May 3, 1987 |newspaper=The New York Times |agency=Associated Press}}</ref> The upper portion of Turnbull's Bend was referred to as ''Upper Old River,'' while the larger, lower portion became known as the ''Lower Old River''.
At first, the Lower Old River would flow eastward, to the Mississippi, until 1839, when locals began removing the [[Great Raft]], a natural log jam that was obstructing the Atchafalaya River. The project was finished in 1840. After that, the Lower Old River would flow eastward to the Mississippi when the Red River was high and the Mississippi was low, and westward to the Atchafalaya when the Mississippi was high and the Red River was low. Over time, the number of days when the river flowed east to the Mississippi decreased and the number of days when the river flowed west increased, until eventually the Lower Old River flowed west over half the time. By 1880, it rarely flowed eastward and was rapidly capturing more and more of the flow of the Mississippi. With this increased water flow, the channel of the Atchafalaya River was worn deeper and wider throughout the 1800s and early 1900s.<ref name="nytimes" />
The U.S. Army Corps of Engineers measured the amount of water flowing through the Mississippi River and compared it to the amount entering the Atchafalaya Basin by monitoring "latitude flow" at the latitude of the [[Red River Landing, Louisiana|Red River Landing]], located {{convert|5|mi|km|spell=in}} downstream of Old River. In this case, latitude flow is a combination of the flows of the Mississippi and Atchafalaya rivers as they cross an imaginary line at that latitude.<ref name="AmericasWetlands" />
Between 1850 and 1950, the percentage of latitude flow entering the Atchafalaya River had increased from less than 10 percent to about 30 percent. By 1953, the U.S. Army Corps of Engineers concluded that the Mississippi River could change its course to the Atchafalaya River by 1990 if it were not controlled, since this alternative path to the [[Gulf of Mexico]] through the Atchafalaya River is much shorter and steeper.
The Corps completed construction on the Old River Control Structure in 1963 to prevent the main channel flow of the Mississippi River from altering its current course to the Gulf of Mexico through the natural geologic process of [[Avulsion (river)|avulsion]].<ref name="AmericasWetlands" /><ref name="DailyImpact">{{cite web |title=Mississippi Rising: Apocalypse Now? |date=April 28, 2011 |url=http://www.dailyimpact.net/2011/04/28/mississippi-rising-apocalypse-now/ |publisher=Daily Impact |access-date=May 10, 2011}}</ref> Historically, this natural process of course change has occurred about every 1,000 years, and is overdue. Some researchers believe the likelihood of this event increases each year, despite manmade artificial control efforts.<ref>{{cite book |last=Daniels |first=Ronald Joel |title=On Risk and Disaster: Lessons from Hurricane Katrina |year=2006 |publisher=University of Pennsylvania Press |page=45}}</ref>
If the Mississippi diverts its main channel to the [[Atchafalaya Basin]] and the [[Atchafalaya River]], it would develop a new [[river delta|delta]] south of [[Morgan City, Louisiana|Morgan City]] in southern Louisiana, greatly reducing water flow to its present channel through [[Baton Rouge]] and [[New Orleans]], with adverse economic effects on both port cities.<ref name="InteractiveMap">{{cite web |url=http://www.mappingsupport.com/p/gmap4.php?q=https://sites.google.com/site/gmap4files/p/news/mississippi_course_change.txt&ll=30.417887,-91.201416&t=h&z=9&label=on |title=Will the Mississippi River change its course in 2011 to the red line? |access-date=May 8, 2011 |publisher=Mappingsupport}}</ref> The [[Mississippi Flood of 1973]] almost caused the control structure to fail. Maintenance of the integrity of the Old River Control Structure, the nearby [[Morganza Spillway]], and other levees in the area is essential to prevent such a diversion. Jeff Masters of ''[[Weather Underground (weather service)|Weather Underground]]'' noted that failure of that complex "would be a serious blow to the U.S. economy."<ref>{{cite web |url=https://www.wunderground.com/blog/JeffMasters/mississippi-river-sets-alltime-flood-records-2nd-major-spillway-open.html |title=Mississippi River sets all-time flood records; 2nd major spillway opens |first=Jeff |last=Masters |publisher=Weather Underground |date=May 9, 2011 |access-date=November 11, 2017}}</ref>
== Components ==
[[File:Mississippi Project Design Flood.tif|thumb|right|upright=2.0|alt=diagram of river flows during Project Design Flood|A diagram that depicts river flows associated with [[Project Design Flood]].]]
The Old River Control Structure (ORCS) and Overbank Control Structure became operational in 1964 and expanded in 1986 with the addition of the Old River Control Auxiliary Structure (ORCAS). The primary one that regulates routine flow in the waterway is the Low Sill Control Structure. The Overbank Structure is only used when the Mississippi exceeds its banks. The ORCAS is used during floods to assist the ORCS and prevent it from being damaged due to high flow rates. ORCAS was added to reduce pressure on the original floodgates after extensive damage caused by the flood of 1973. The northernmost and newest structure is the [[Sidney A. Murray Jr. Hydroelectric Station]], completed in 1990. It provides an additional measure of control at the site.<ref name="AmericasWetlands"/> These four structures are located approximately where the Upper Old River used to be before Shreve's Cut.
A navigation channel and lock are also part of the facility design, but they are situated well south of the other structures on the Lower Old River at the Old River Lock. This makes the Lower Old River navigable, allowing ship and barge traffic between the Mississippi River and the Atchafalaya River/[[Red River of the South]].
All five structures in the complex carry [[Louisiana Highway 15]], starting at the power plant, then the Overbank Structure, then the Low Sill ORCS, followed by ORCAS, the island created between the rivers, and finally the Old River Lock.
== Operation ==
Water from the Mississippi is normally diverted into the Atchafalaya Basin only at Old River, where floodgates are routinely used to redirect the Mississippi's flow into the Atchafalaya River, such that the volume of the two rivers is split 70%/30%, respectively, as measured at the latitude of Red River Landing.<ref>{{cite web |title=Mississippi River at Red River Landing (01120) |url=http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S |date=May 7, 2011 |publisher=United States Army Corps of Engineers |access-date=May 10, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110927153416/http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S |archive-date=September 27, 2011 }}</ref><ref>{{cite web |title=Daily State and Discharge Data - Water Control - New Orleans District |url=http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp |publisher=U.S. Army Corps of Engineers |access-date=May 10, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20040514060639/http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp |archive-date=May 14, 2004 }}</ref> This flow split was not based on science, but rather was based on the approximate flow allocation between the two rivers that existed at the time of construction.<ref name="Piazza2014"/>
Water diverted at Old River flows into the Atchafalaya Basin, first entering the Red River, then continuing down the Atchafalaya River to the Gulf of Mexico, bypassing [[Baton Rouge]] and [[New Orleans]] (see diagram).
The [[Morganza Floodway]], between the Mississippi and the Atchafalaya Basin nearby downstream, is normally closed. It can be opened in an emergency to relieve water levels and water-pressure stress on various levees and other flood-control structures, including the Old River Control Structure. The floodway can reduce stress by diverting additional water from the Mississippi into the Atchafalaya.<ref>{{cite news |url=http://www.nola.com/environment/index.ssf/2011/05/morganza_floodway_opens_to_div.html |title=Morganza Floodway opens to divert Mississippi River away from Baton Rouge, New Orleans |newspaper=NOLA.com |first=Paul |last=Rioux |date=May 14, 2011}}</ref> The Morganza Floodway was never used before the construction of Old River Control Structure, and as of 2016 has been opened only twice <ref>{{cite web|url=http://www.nola.com/weather/index.ssf/2016/01/morganza_floodway_will_not_be.html|title=Morganza Floodway will not be opened, Corps of Engineers decides|date=27 September 2023 }}</ref> for flood control since completion of the Old River Control Structure.
== See also ==
*[[Lower Mississippi River]]
== References ==
{{Reflist|2}}
== External sources ==
{{Commons category}}
*{{cite web |url=http://www.johnweeks.com/river_mississippi/pages/lmiss23.html |title=Old River Control Structure |last=Weeks |first=John |access-date=2014-09-20 }}
{{Coord|31.0768|-91.5979 |format=dms |region:US-LA_type:landmark |display=title}}
{{authority control}}
[[Category:Rivers of Louisiana]]
[[Category:Buildings and structures in Concordia Parish, Louisiana]]
[[Category:Dikes in the United States]]
[[Category:United States Army Corps of Engineers dams]]
[[Category:1963 establishments in Louisiana]]' |
New page wikitext, after the edit (new_wikitext) | '== Old River ==
[[File:Geomorphology of Old River.jpg|thumb|left|300 px|Formation of the Atchafalaya River and construction of the Old River Control Structure.]]
Before the 15th century, the [[Red River of the South|Red River]] and Mississippi River were entirely separate and flowed more or less parallel to one another.<ref name="AmericasWetlands">{{cite web |title=Louisiana Old River Control Structure and Mississippi river flood protection |url=http://www.americaswetlandresources.com/background_facts/detailedstory/LouisianaRiverControl.html |work=America's Wetland Resource Center |publisher=Loyola University's Center for Environmental Communication |access-date=2007-04-01 |archive-date=2016-03-10 |archive-url=https://web.archive.org/web/20160310124727/http://www.americaswetlandresources.com/background_facts/detailedstory/LouisianaRiverControl.html |url-status=dead }}</ref> Beginning in the 15th century, the Mississippi River created a small, westward, [[meander|oxbow loop]], later called Turnbull's Bend, near present-day [[Angola, Louisiana]]. This loop eventually intersected the Red River, making the downstream part of the Red River a distributary of the Mississippi; this distributary came to be called the [[Atchafalaya River]].<ref name="AmericasWetlands" />
In the heyday of [[steamboat]]s along the Mississippi River, such a vessel would need several hours to travel the {{convert|20|mi|km}} of Turnbull's Bend, after which it would have progressed only about {{convert|1|mi|km}} from the entrance to the bend. To reduce travel time, Captain [[Henry Miller Shreve|Henry M. Shreve]], a river engineer and namesake of [[Shreveport, Louisiana|Shreveport]], Louisiana, dug a canal in 1831 through the neck of Turnbull's Bend; this canal became known as Shreve's Cut. At the next high water, the Mississippi roared through this channel.<ref name="nytimes">{{cite news |url=https://www.nytimes.com/1987/05/03/us/612487.html |title=$500 Million (and Rising) to Contain a River |date=May 3, 1987 |newspaper=The New York Times |agency=Associated Press}}</ref> The upper portion of Turnbull's Bend was referred to as ''Upper Old River,'' while the larger, lower portion became known as the ''Lower Old River''.
At first, the Lower Old River would flow eastward, to the Mississippi, until 1839, when locals began removing the [[Great Raft]], a natural log jam that was obstructing the Atchafalaya River. The project was finished in 1840. After that, the Lower Old River would flow eastward to the Mississippi when the Red River was high and the Mississippi was low, and westward to the Atchafalaya when the Mississippi was high and the Red River was low. Over time, the number of days when the river flowed east to the Mississippi decreased and the number of days when the river flowed west increased, until eventually the Lower Old River flowed west over half the time. By 1880, it rarely flowed eastward and was rapidly capturing more and more of the flow of the Mississippi. With this increased water flow, the channel of the Atchafalaya River was worn deeper and wider throughout the 1800s and early 1900s.<ref name="nytimes" />
The U.S. Army Corps of Engineers measured the amount of water flowing through the Mississippi River and compared it to the amount entering the Atchafalaya Basin by monitoring "latitude flow" at the latitude of the [[Red River Landing, Louisiana|Red River Landing]], located {{convert|5|mi|km|spell=in}} downstream of Old River. In this case, latitude flow is a combination of the flows of the Mississippi and Atchafalaya rivers as they cross an imaginary line at that latitude.<ref name="AmericasWetlands" />
Between 1850 and 1950, the percentage of latitude flow entering the Atchafalaya River had increased from less than 10 percent to about 30 percent. By 1953, the U.S. Army Corps of Engineers concluded that the Mississippi River could change its course to the Atchafalaya River by 1990 if it were not controlled, since this alternative path to the [[Gulf of Mexico]] through the Atchafalaya River is much shorter and steeper.
The Corps completed construction on the Old River Control Structure in 1963 to prevent the main channel flow of the Mississippi River from altering its current course to the Gulf of Mexico through the natural geologic process of [[Avulsion (river)|avulsion]].<ref name="AmericasWetlands" /><ref name="DailyImpact">{{cite web |title=Mississippi Rising: Apocalypse Now? |date=April 28, 2011 |url=http://www.dailyimpact.net/2011/04/28/mississippi-rising-apocalypse-now/ |publisher=Daily Impact |access-date=May 10, 2011}}</ref> Historically, this natural process of course change has occurred about every 1,000 years, and is overdue. Some researchers believe the likelihood of this event increases each year, despite manmade artificial control efforts.<ref>{{cite book |last=Daniels |first=Ronald Joel |title=On Risk and Disaster: Lessons from Hurricane Katrina |year=2006 |publisher=University of Pennsylvania Press |page=45}}</ref>
If the Mississippi diverts its main channel to the [[Atchafalaya Basin]] and the [[Atchafalaya River]], it would develop a new [[river delta|delta]] south of [[Morgan City, Louisiana|Morgan City]] in southern Louisiana, greatly reducing water flow to its present channel through [[Baton Rouge]] and [[New Orleans]], with adverse economic effects on both port cities.<ref name="InteractiveMap">{{cite web |url=http://www.mappingsupport.com/p/gmap4.php?q=https://sites.google.com/site/gmap4files/p/news/mississippi_course_change.txt&ll=30.417887,-91.201416&t=h&z=9&label=on |title=Will the Mississippi River change its course in 2011 to the red line? |access-date=May 8, 2011 |publisher=Mappingsupport}}</ref> The [[Mississippi Flood of 1973]] almost caused the control structure to fail. Maintenance of the integrity of the Old River Control Structure, the nearby [[Morganza Spillway]], and other levees in the area is essential to prevent such a diversion. Jeff Masters of ''[[Weather Underground (weather service)|Weather Underground]]'' noted that failure of that complex "would be a serious blow to the U.S. economy."<ref>{{cite web |url=https://www.wunderground.com/blog/JeffMasters/mississippi-river-sets-alltime-flood-records-2nd-major-spillway-open.html |title=Mississippi River sets all-time flood records; 2nd major spillway opens |first=Jeff |last=Masters |publisher=Weather Underground |date=May 9, 2011 |access-date=November 11, 2017}}</ref>
== Components ==
[[File:Mississippi Project Design Flood.tif|thumb|right|upright=2.0|alt=diagram of river flows during Project Design Flood|A diagram that depicts river flows associated with [[Project Design Flood]].]]
The Old River Control Structure (ORCS) and Overbank Control Structure became operational in 1964 and expanded in 1986 with the addition of the Old River Control Auxiliary Structure (ORCAS). The primary one that regulates routine flow in the waterway is the Low Sill Control Structure. The Overbank Structure is only used when the Mississippi exceeds its banks. The ORCAS is used during floods to assist the ORCS and prevent it from being damaged due to high flow rates. ORCAS was added to reduce pressure on the original floodgates after extensive damage caused by the flood of 1973. The northernmost and newest structure is the [[Sidney A. Murray Jr. Hydroelectric Station]], completed in 1990. It provides an additional measure of control at the site.<ref name="AmericasWetlands"/> These four structures are located approximately where the Upper Old River used to be before Shreve's Cut.
A navigation channel and lock are also part of the facility design, but they are situated well south of the other structures on the Lower Old River at the Old River Lock. This makes the Lower Old River navigable, allowing ship and barge traffic between the Mississippi River and the Atchafalaya River/[[Red River of the South]].
All five structures in the complex carry [[Louisiana Highway 15]], starting at the power plant, then the Overbank Structure, then the Low Sill ORCS, followed by ORCAS, the island created between the rivers, and finally the Old River Lock.
== Operation ==
Water from the Mississippi is normally diverted into the Atchafalaya Basin only at Old River, where floodgates are routinely used to redirect the Mississippi's flow into the Atchafalaya River, such that the volume of the two rivers is split 70%/30%, respectively, as measured at the latitude of Red River Landing.<ref>{{cite web |title=Mississippi River at Red River Landing (01120) |url=http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S |date=May 7, 2011 |publisher=United States Army Corps of Engineers |access-date=May 10, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110927153416/http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S |archive-date=September 27, 2011 }}</ref><ref>{{cite web |title=Daily State and Discharge Data - Water Control - New Orleans District |url=http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp |publisher=U.S. Army Corps of Engineers |access-date=May 10, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20040514060639/http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp |archive-date=May 14, 2004 }}</ref> This flow split was not based on science, but rather was based on the approximate flow allocation between the two rivers that existed at the time of construction.<ref name="Piazza2014"/>
Water diverted at Old River flows into the Atchafalaya Basin, first entering the Red River, then continuing down the Atchafalaya River to the Gulf of Mexico, bypassing [[Baton Rouge]] and [[New Orleans]] (see diagram).
The [[Morganza Floodway]], between the Mississippi and the Atchafalaya Basin nearby downstream, is normally closed. It can be opened in an emergency to relieve water levels and water-pressure stress on various levees and other flood-control structures, including the Old River Control Structure. The floodway can reduce stress by diverting additional water from the Mississippi into the Atchafalaya.<ref>{{cite news |url=http://www.nola.com/environment/index.ssf/2011/05/morganza_floodway_opens_to_div.html |title=Morganza Floodway opens to divert Mississippi River away from Baton Rouge, New Orleans |newspaper=NOLA.com |first=Paul |last=Rioux |date=May 14, 2011}}</ref> The Morganza Floodway was never used before the construction of Old River Control Structure, and as of 2016 has been opened only twice <ref>{{cite web|url=http://www.nola.com/weather/index.ssf/2016/01/morganza_floodway_will_not_be.html|title=Morganza Floodway will not be opened, Corps of Engineers decides|date=27 September 2023 }}</ref> for flood control since completion of the Old River Control Structure.
== See also ==
*[[Lower Mississippi River]]
== References ==
{{Reflist|2}}
== External sources ==
{{Commons category}}
*{{cite web |url=http://www.johnweeks.com/river_mississippi/pages/lmiss23.html |title=Old River Control Structure |last=Weeks |first=John |access-date=2014-09-20 }}
{{Coord|31.0768|-91.5979 |format=dms |region:US-LA_type:landmark |display=title}}
{{authority control}}
[[Category:Rivers of Louisiana]]
[[Category:Buildings and structures in Concordia Parish, Louisiana]]
[[Category:Dikes in the United States]]
[[Category:United States Army Corps of Engineers dams]]
[[Category:1963 establishments in Louisiana]]' |
Unified diff of changes made by edit (edit_diff) | '@@ -1,10 +1,2 @@
-{{Short description|Floodgate system in Louisiana, USA}}
-[[File:Old River Control Structure Complex.jpg|right|thumb|The Old River Control Structure complex. View is to the [[east-southeast]], looking downriver on the [[Mississippi River|Mississippi]], with the three [[dam]]s across channels leading to the [[Atchafalaya River]] to the right of the Mississippi. [[Concordia Parish, Louisiana]] is in the foreground, on the right, and [[Wilkinson County, Mississippi]], is in the background, across the Mississippi on the left.]]
-[[File:Old River Control discharge.jpg|right|thumb|Old River low-sill control structure discharging water into the Atchafalaya, May 2011]]
-
-The '''Old River Control Structure''' is a [[floodgate]] system in a branch of the [[Mississippi River]] in central [[Louisiana]]. It regulates the flow of water from the Mississippi into the [[Atchafalaya River]], thereby preventing the Mississippi River from changing course. Completed in 1963, the complex was built by the [[U.S. Army Corps of Engineers]] in a side channel of the Mississippi known as "Old River", between the Mississippi's current channel and the [[Atchafalaya Basin]], a former channel of the Mississippi.<ref>{{cite magazine |last=McPhee |first=John |title=The Control of Nature: Atchafalaya |magazine=The New Yorker |date=February 23, 1987 |url=http://www.newyorker.com/archive/1987/02/23/1987_02_23_039_TNY_CARDS_000347146 |access-date=May 12, 2011}} Republished in {{cite book |last=McPhee |first=John |title=The Control of Nature |publisher=Farrar, Straus and Giroux |year=1989 |isbn=978-0-374-12890-6}}</ref><ref>{{cite web | title=Old River Control | work=The Mighty Mississippi River | author=Angert, Joe and Isaac | url=http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-url=https://web.archive.org/web/20090515010700/http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-date=May 15, 2009 |access-date=2011-05-12}}. Includes map and pictures.</ref><ref name="AmericasWetlands"/><ref name="InteractiveMap" /><ref name="kemp">{{cite web |url=http://www.tulane.edu/~bfleury/envirobio/enviroweb/FloodControl.htm |title=The Mississippi Levee System and the Old River Control Structure |first=Katherine |last=Kemp |date=January 6, 2000}}</ref>
-
-The Old River Control Structure is a complex containing the original low-sill<ref>{{Cite web | url=http://www.uoguelph.ca/geology/geol2250/glossary/HTML%20files/lowsillstructure.html | title=Low Sill Structure}}</ref> and overbank<ref>{{cite web|url=https://www.johnweeks.com/river_mississippi/pages/lmiss23.html|title=Old River Control Structure, Point Breeze, LA|website=www.johnweeks.com}}</ref> structures, as well as the auxiliary structure that was constructed after the low-sill structure was damaged during the [[Mississippi flood of 1973|Mississippi River Flood of 1973]]. The complex also contains a navigation lock and the Sidney A. Murray Jr. Hydroelectric Station.<ref name=Piazza2014>{{cite book |last=Piazza |first=Bryan P. |title=The Atchafalaya River Basin: History and Ecology of an American Wetland |year=2014 |publisher=Texas A&M University Press |isbn=978-1-62349-039-3}}</ref>
-
== Old River ==
[[File:Geomorphology of Old River.jpg|thumb|left|300 px|Formation of the Atchafalaya River and construction of the Old River Control Structure.]]
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1 => '[[File:Old River Control Structure Complex.jpg|right|thumb|The Old River Control Structure complex. View is to the [[east-southeast]], looking downriver on the [[Mississippi River|Mississippi]], with the three [[dam]]s across channels leading to the [[Atchafalaya River]] to the right of the Mississippi. [[Concordia Parish, Louisiana]] is in the foreground, on the right, and [[Wilkinson County, Mississippi]], is in the background, across the Mississippi on the left.]]',
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4 => 'The '''Old River Control Structure''' is a [[floodgate]] system in a branch of the [[Mississippi River]] in central [[Louisiana]]. It regulates the flow of water from the Mississippi into the [[Atchafalaya River]], thereby preventing the Mississippi River from changing course. Completed in 1963, the complex was built by the [[U.S. Army Corps of Engineers]] in a side channel of the Mississippi known as "Old River", between the Mississippi's current channel and the [[Atchafalaya Basin]], a former channel of the Mississippi.<ref>{{cite magazine |last=McPhee |first=John |title=The Control of Nature: Atchafalaya |magazine=The New Yorker |date=February 23, 1987 |url=http://www.newyorker.com/archive/1987/02/23/1987_02_23_039_TNY_CARDS_000347146 |access-date=May 12, 2011}} Republished in {{cite book |last=McPhee |first=John |title=The Control of Nature |publisher=Farrar, Straus and Giroux |year=1989 |isbn=978-0-374-12890-6}}</ref><ref>{{cite web | title=Old River Control | work=The Mighty Mississippi River | author=Angert, Joe and Isaac | url=http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-url=https://web.archive.org/web/20090515010700/http://users.stlcc.edu/jangert/oldriver/oldriver.html |archive-date=May 15, 2009 |access-date=2011-05-12}}. Includes map and pictures.</ref><ref name="AmericasWetlands"/><ref name="InteractiveMap" /><ref name="kemp">{{cite web |url=http://www.tulane.edu/~bfleury/envirobio/enviroweb/FloodControl.htm |title=The Mississippi Levee System and the Old River Control Structure |first=Katherine |last=Kemp |date=January 6, 2000}}</ref> ',
5 => '',
6 => 'The Old River Control Structure is a complex containing the original low-sill<ref>{{Cite web | url=http://www.uoguelph.ca/geology/geol2250/glossary/HTML%20files/lowsillstructure.html | title=Low Sill Structure}}</ref> and overbank<ref>{{cite web|url=https://www.johnweeks.com/river_mississippi/pages/lmiss23.html|title=Old River Control Structure, Point Breeze, LA|website=www.johnweeks.com}}</ref> structures, as well as the auxiliary structure that was constructed after the low-sill structure was damaged during the [[Mississippi flood of 1973|Mississippi River Flood of 1973]]. The complex also contains a navigation lock and the Sidney A. Murray Jr. Hydroelectric Station.<ref name=Piazza2014>{{cite book |last=Piazza |first=Bryan P. |title=The Atchafalaya River Basin: History and Ecology of an American Wetland |year=2014 |publisher=Texas A&M University Press |isbn=978-1-62349-039-3}}</ref>',
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Parsed HTML source of the new revision (new_html) | '<div class="mw-parser-output"><div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#Old_River"><span class="tocnumber">1</span> <span class="toctext">Old River</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="#Components"><span class="tocnumber">2</span> <span class="toctext">Components</span></a></li>
<li class="toclevel-1 tocsection-3"><a href="#Operation"><span class="tocnumber">3</span> <span class="toctext">Operation</span></a></li>
<li class="toclevel-1 tocsection-4"><a href="#See_also"><span class="tocnumber">4</span> <span class="toctext">See also</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="#References"><span class="tocnumber">5</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="#External_sources"><span class="tocnumber">6</span> <span class="toctext">External sources</span></a></li>
</ul>
</div>
<h2><span class="mw-headline" id="Old_River">Old River</span></h2>
<figure class="mw-halign-left" typeof="mw:File/Thumb"><a href="/enwiki/wiki/File:Geomorphology_of_Old_River.jpg" class="mw-file-description"><img src="/upwiki/wikipedia/commons/thumb/7/7a/Geomorphology_of_Old_River.jpg/300px-Geomorphology_of_Old_River.jpg" decoding="async" width="300" height="265" class="mw-file-element" srcset="/upwiki/wikipedia/commons/thumb/7/7a/Geomorphology_of_Old_River.jpg/450px-Geomorphology_of_Old_River.jpg 1.5x, /upwiki/wikipedia/commons/thumb/7/7a/Geomorphology_of_Old_River.jpg/600px-Geomorphology_of_Old_River.jpg 2x" data-file-width="959" data-file-height="847" /></a><figcaption>Formation of the Atchafalaya River and construction of the Old River Control Structure.</figcaption></figure>
<p>Before the 15th century, the <a href="/enwiki/wiki/Red_River_of_the_South" title="Red River of the South">Red River</a> and Mississippi River were entirely separate and flowed more or less parallel to one another.<sup id="cite_ref-AmericasWetlands_1-0" class="reference"><a href="#cite_note-AmericasWetlands-1">[1]</a></sup> Beginning in the 15th century, the Mississippi River created a small, westward, <a href="/enwiki/wiki/Meander" title="Meander">oxbow loop</a>, later called Turnbull's Bend, near present-day <a href="/enwiki/wiki/Angola,_Louisiana" class="mw-redirect" title="Angola, Louisiana">Angola, Louisiana</a>. This loop eventually intersected the Red River, making the downstream part of the Red River a distributary of the Mississippi; this distributary came to be called the <a href="/enwiki/wiki/Atchafalaya_River" title="Atchafalaya River">Atchafalaya River</a>.<sup id="cite_ref-AmericasWetlands_1-1" class="reference"><a href="#cite_note-AmericasWetlands-1">[1]</a></sup>
</p><p>In the heyday of <a href="/enwiki/wiki/Steamboat" title="Steamboat">steamboats</a> along the Mississippi River, such a vessel would need several hours to travel the 20 miles (32 km) of Turnbull's Bend, after which it would have progressed only about 1 mile (1.6 km) from the entrance to the bend. To reduce travel time, Captain <a href="/enwiki/wiki/Henry_Miller_Shreve" title="Henry Miller Shreve">Henry M. Shreve</a>, a river engineer and namesake of <a href="/enwiki/wiki/Shreveport,_Louisiana" title="Shreveport, Louisiana">Shreveport</a>, Louisiana, dug a canal in 1831 through the neck of Turnbull's Bend; this canal became known as Shreve's Cut. At the next high water, the Mississippi roared through this channel.<sup id="cite_ref-nytimes_2-0" class="reference"><a href="#cite_note-nytimes-2">[2]</a></sup> The upper portion of Turnbull's Bend was referred to as <i>Upper Old River,</i> while the larger, lower portion became known as the <i>Lower Old River</i>.
</p><p>At first, the Lower Old River would flow eastward, to the Mississippi, until 1839, when locals began removing the <a href="/enwiki/wiki/Great_Raft" title="Great Raft">Great Raft</a>, a natural log jam that was obstructing the Atchafalaya River. The project was finished in 1840. After that, the Lower Old River would flow eastward to the Mississippi when the Red River was high and the Mississippi was low, and westward to the Atchafalaya when the Mississippi was high and the Red River was low. Over time, the number of days when the river flowed east to the Mississippi decreased and the number of days when the river flowed west increased, until eventually the Lower Old River flowed west over half the time. By 1880, it rarely flowed eastward and was rapidly capturing more and more of the flow of the Mississippi. With this increased water flow, the channel of the Atchafalaya River was worn deeper and wider throughout the 1800s and early 1900s.<sup id="cite_ref-nytimes_2-1" class="reference"><a href="#cite_note-nytimes-2">[2]</a></sup>
</p><p>The U.S. Army Corps of Engineers measured the amount of water flowing through the Mississippi River and compared it to the amount entering the Atchafalaya Basin by monitoring "latitude flow" at the latitude of the <a href="/enwiki/wiki/Red_River_Landing,_Louisiana" title="Red River Landing, Louisiana">Red River Landing</a>, located five miles (8.0 km) downstream of Old River. In this case, latitude flow is a combination of the flows of the Mississippi and Atchafalaya rivers as they cross an imaginary line at that latitude.<sup id="cite_ref-AmericasWetlands_1-2" class="reference"><a href="#cite_note-AmericasWetlands-1">[1]</a></sup>
</p><p>Between 1850 and 1950, the percentage of latitude flow entering the Atchafalaya River had increased from less than 10 percent to about 30 percent. By 1953, the U.S. Army Corps of Engineers concluded that the Mississippi River could change its course to the Atchafalaya River by 1990 if it were not controlled, since this alternative path to the <a href="/enwiki/wiki/Gulf_of_Mexico" title="Gulf of Mexico">Gulf of Mexico</a> through the Atchafalaya River is much shorter and steeper.
</p><p>The Corps completed construction on the Old River Control Structure in 1963 to prevent the main channel flow of the Mississippi River from altering its current course to the Gulf of Mexico through the natural geologic process of <a href="/enwiki/wiki/Avulsion_(river)" title="Avulsion (river)">avulsion</a>.<sup id="cite_ref-AmericasWetlands_1-3" class="reference"><a href="#cite_note-AmericasWetlands-1">[1]</a></sup><sup id="cite_ref-DailyImpact_3-0" class="reference"><a href="#cite_note-DailyImpact-3">[3]</a></sup> Historically, this natural process of course change has occurred about every 1,000 years, and is overdue. Some researchers believe the likelihood of this event increases each year, despite manmade artificial control efforts.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4">[4]</a></sup>
</p><p>If the Mississippi diverts its main channel to the <a href="/enwiki/wiki/Atchafalaya_Basin" title="Atchafalaya Basin">Atchafalaya Basin</a> and the <a href="/enwiki/wiki/Atchafalaya_River" title="Atchafalaya River">Atchafalaya River</a>, it would develop a new <a href="/enwiki/wiki/River_delta" title="River delta">delta</a> south of <a href="/enwiki/wiki/Morgan_City,_Louisiana" title="Morgan City, Louisiana">Morgan City</a> in southern Louisiana, greatly reducing water flow to its present channel through <a href="/enwiki/wiki/Baton_Rouge" class="mw-redirect" title="Baton Rouge">Baton Rouge</a> and <a href="/enwiki/wiki/New_Orleans" title="New Orleans">New Orleans</a>, with adverse economic effects on both port cities.<sup id="cite_ref-InteractiveMap_5-0" class="reference"><a href="#cite_note-InteractiveMap-5">[5]</a></sup> The <a href="/enwiki/wiki/Mississippi_Flood_of_1973" class="mw-redirect" title="Mississippi Flood of 1973">Mississippi Flood of 1973</a> almost caused the control structure to fail. Maintenance of the integrity of the Old River Control Structure, the nearby <a href="/enwiki/wiki/Morganza_Spillway" title="Morganza Spillway">Morganza Spillway</a>, and other levees in the area is essential to prevent such a diversion. Jeff Masters of <i><a href="/enwiki/wiki/Weather_Underground_(weather_service)" title="Weather Underground (weather service)">Weather Underground</a></i> noted that failure of that complex "would be a serious blow to the U.S. economy."<sup id="cite_ref-6" class="reference"><a href="#cite_note-6">[6]</a></sup>
</p>
<h2><span class="mw-headline" id="Components">Components</span></h2>
<figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/enwiki/wiki/File:Mississippi_Project_Design_Flood.tif" class="mw-file-description"><img alt="diagram of river flows during Project Design Flood" src="/upwiki/wikipedia/commons/thumb/7/78/Mississippi_Project_Design_Flood.tif/lossless-page1-440px-Mississippi_Project_Design_Flood.tif.png" decoding="async" width="440" height="330" class="mw-file-element" srcset="/upwiki/wikipedia/commons/thumb/7/78/Mississippi_Project_Design_Flood.tif/lossless-page1-660px-Mississippi_Project_Design_Flood.tif.png 1.5x, /upwiki/wikipedia/commons/thumb/7/78/Mississippi_Project_Design_Flood.tif/lossless-page1-880px-Mississippi_Project_Design_Flood.tif.png 2x" data-file-width="1502" data-file-height="1127" /></a><figcaption>A diagram that depicts river flows associated with <a href="/enwiki/wiki/Project_Design_Flood" class="mw-redirect" title="Project Design Flood">Project Design Flood</a>.</figcaption></figure>
<p>The Old River Control Structure (ORCS) and Overbank Control Structure became operational in 1964 and expanded in 1986 with the addition of the Old River Control Auxiliary Structure (ORCAS). The primary one that regulates routine flow in the waterway is the Low Sill Control Structure. The Overbank Structure is only used when the Mississippi exceeds its banks. The ORCAS is used during floods to assist the ORCS and prevent it from being damaged due to high flow rates. ORCAS was added to reduce pressure on the original floodgates after extensive damage caused by the flood of 1973. The northernmost and newest structure is the <a href="/enwiki/wiki/Sidney_A._Murray_Jr._Hydroelectric_Station" title="Sidney A. Murray Jr. Hydroelectric Station">Sidney A. Murray Jr. Hydroelectric Station</a>, completed in 1990. It provides an additional measure of control at the site.<sup id="cite_ref-AmericasWetlands_1-4" class="reference"><a href="#cite_note-AmericasWetlands-1">[1]</a></sup> These four structures are located approximately where the Upper Old River used to be before Shreve's Cut.
</p><p>A navigation channel and lock are also part of the facility design, but they are situated well south of the other structures on the Lower Old River at the Old River Lock. This makes the Lower Old River navigable, allowing ship and barge traffic between the Mississippi River and the Atchafalaya River/<a href="/enwiki/wiki/Red_River_of_the_South" title="Red River of the South">Red River of the South</a>.
</p><p>All five structures in the complex carry <a href="/enwiki/wiki/Louisiana_Highway_15" title="Louisiana Highway 15">Louisiana Highway 15</a>, starting at the power plant, then the Overbank Structure, then the Low Sill ORCS, followed by ORCAS, the island created between the rivers, and finally the Old River Lock.
</p>
<h2><span class="mw-headline" id="Operation">Operation</span></h2>
<p>Water from the Mississippi is normally diverted into the Atchafalaya Basin only at Old River, where floodgates are routinely used to redirect the Mississippi's flow into the Atchafalaya River, such that the volume of the two rivers is split 70%/30%, respectively, as measured at the latitude of Red River Landing.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7">[7]</a></sup><sup id="cite_ref-8" class="reference"><a href="#cite_note-8">[8]</a></sup> This flow split was not based on science, but rather was based on the approximate flow allocation between the two rivers that existed at the time of construction.<sup id="cite_ref-Piazza2014_9-0" class="reference"><a href="#cite_note-Piazza2014-9">[9]</a></sup>
</p><p>Water diverted at Old River flows into the Atchafalaya Basin, first entering the Red River, then continuing down the Atchafalaya River to the Gulf of Mexico, bypassing <a href="/enwiki/wiki/Baton_Rouge" class="mw-redirect" title="Baton Rouge">Baton Rouge</a> and <a href="/enwiki/wiki/New_Orleans" title="New Orleans">New Orleans</a> (see diagram).
</p><p>The <a href="/enwiki/wiki/Morganza_Floodway" class="mw-redirect" title="Morganza Floodway">Morganza Floodway</a>, between the Mississippi and the Atchafalaya Basin nearby downstream, is normally closed. It can be opened in an emergency to relieve water levels and water-pressure stress on various levees and other flood-control structures, including the Old River Control Structure. The floodway can reduce stress by diverting additional water from the Mississippi into the Atchafalaya.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10">[10]</a></sup> The Morganza Floodway was never used before the construction of Old River Control Structure, and as of 2016 has been opened only twice <sup id="cite_ref-11" class="reference"><a href="#cite_note-11">[11]</a></sup> for flood control since completion of the Old River Control Structure.
</p>
<h2><span class="mw-headline" id="See_also">See also</span></h2>
<ul><li><a href="/enwiki/wiki/Lower_Mississippi_River" title="Lower Mississippi River">Lower Mississippi River</a></li></ul>
<h2><span class="mw-headline" id="References">References</span></h2>
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<ol class="references">
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<li id="cite_note-nytimes-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-nytimes_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-nytimes_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.nytimes.com/1987/05/03/us/612487.html">"$500 Million (and Rising) to Contain a River"</a>. <i>The New York Times</i>. Associated Press. May 3, 1987.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=%24500+Million+%28and+Rising%29+to+Contain+a+River&rft.date=1987-05-03&rft_id=https%3A%2F%2Fwww.nytimes.com%2F1987%2F05%2F03%2Fus%2F612487.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-DailyImpact-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-DailyImpact_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.dailyimpact.net/2011/04/28/mississippi-rising-apocalypse-now/">"Mississippi Rising: Apocalypse Now?"</a>. Daily Impact. April 28, 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">May 10,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Mississippi+Rising%3A+Apocalypse+Now%3F&rft.pub=Daily+Impact&rft.date=2011-04-28&rft_id=http%3A%2F%2Fwww.dailyimpact.net%2F2011%2F04%2F28%2Fmississippi-rising-apocalypse-now%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite id="CITEREFDaniels2006" class="citation book cs1">Daniels, Ronald Joel (2006). <i>On Risk and Disaster: Lessons from Hurricane Katrina</i>. University of Pennsylvania Press. p. 45.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=On+Risk+and+Disaster%3A+Lessons+from+Hurricane+Katrina&rft.pages=45&rft.pub=University+of+Pennsylvania+Press&rft.date=2006&rft.aulast=Daniels&rft.aufirst=Ronald+Joel&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-InteractiveMap-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-InteractiveMap_5-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.mappingsupport.com/p/gmap4.php?q=https://sites.google.com/site/gmap4files/p/news/mississippi_course_change.txt&ll=30.417887,-91.201416&t=h&z=9&label=on">"Will the Mississippi River change its course in 2011 to the red line?"</a>. Mappingsupport<span class="reference-accessdate">. Retrieved <span class="nowrap">May 8,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Will+the+Mississippi+River+change+its+course+in+2011+to+the+red+line%3F&rft.pub=Mappingsupport&rft_id=http%3A%2F%2Fwww.mappingsupport.com%2Fp%2Fgmap4.php%3Fq%3Dhttps%3A%2F%2Fsites.google.com%2Fsite%2Fgmap4files%2Fp%2Fnews%2Fmississippi_course_change.txt%26ll%3D30.417887%2C-91.201416%26t%3Dh%26z%3D9%26label%3Don&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite id="CITEREFMasters2011" class="citation web cs1">Masters, Jeff (May 9, 2011). <a rel="nofollow" class="external text" href="https://www.wunderground.com/blog/JeffMasters/mississippi-river-sets-alltime-flood-records-2nd-major-spillway-open.html">"Mississippi River sets all-time flood records; 2nd major spillway opens"</a>. Weather Underground<span class="reference-accessdate">. Retrieved <span class="nowrap">November 11,</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Mississippi+River+sets+all-time+flood+records%3B+2nd+major+spillway+opens&rft.pub=Weather+Underground&rft.date=2011-05-09&rft.aulast=Masters&rft.aufirst=Jeff&rft_id=https%3A%2F%2Fwww.wunderground.com%2Fblog%2FJeffMasters%2Fmississippi-river-sets-alltime-flood-records-2nd-major-spillway-open.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110927153416/http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S">"Mississippi River at Red River Landing (01120)"</a>. United States Army Corps of Engineers. May 7, 2011. Archived from <a rel="nofollow" class="external text" href="http://www2.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01120&fid=BTRL1&dt=S">the original</a> on September 27, 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">May 10,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Mississippi+River+at+Red+River+Landing+%2801120%29&rft.pub=United+States+Army+Corps+of+Engineers&rft.date=2011-05-07&rft_id=http%3A%2F%2Fwww2.mvr.usace.army.mil%2FWaterControl%2Fstationinfo2.cfm%3Fsid%3D01120%26fid%3DBTRL1%26dt%3DS&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20040514060639/http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp">"Daily State and Discharge Data - Water Control - New Orleans District"</a>. U.S. Army Corps of Engineers. Archived from <a rel="nofollow" class="external text" href="http://www.mvn.usace.army.mil/eng/edhd/dailystagedisplay.asp">the original</a> on May 14, 2004<span class="reference-accessdate">. Retrieved <span class="nowrap">May 10,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Daily+State+and+Discharge+Data+-+Water+Control+-+New+Orleans+District&rft.pub=U.S.+Army+Corps+of+Engineers&rft_id=http%3A%2F%2Fwww.mvn.usace.army.mil%2Feng%2Fedhd%2Fdailystagedisplay.asp&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-Piazza2014-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-Piazza2014_9-0">^</a></b></span> <span class="error mw-ext-cite-error" lang="en" dir="ltr">Cite error: The named reference <code>Piazza2014</code> was invoked but never defined (see the <a href="/enwiki/wiki/Help:Cite_errors/Cite_error_references_no_text" title="Help:Cite errors/Cite error references no text">help page</a>).</span></li>
<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite id="CITEREFRioux2011" class="citation news cs1">Rioux, Paul (May 14, 2011). <a rel="nofollow" class="external text" href="http://www.nola.com/environment/index.ssf/2011/05/morganza_floodway_opens_to_div.html">"Morganza Floodway opens to divert Mississippi River away from Baton Rouge, New Orleans"</a>. <i>NOLA.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NOLA.com&rft.atitle=Morganza+Floodway+opens+to+divert+Mississippi+River+away+from+Baton+Rouge%2C+New+Orleans&rft.date=2011-05-14&rft.aulast=Rioux&rft.aufirst=Paul&rft_id=http%3A%2F%2Fwww.nola.com%2Fenvironment%2Findex.ssf%2F2011%2F05%2Fmorganza_floodway_opens_to_div.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.nola.com/weather/index.ssf/2016/01/morganza_floodway_will_not_be.html">"Morganza Floodway will not be opened, Corps of Engineers decides"</a>. 27 September 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Morganza+Floodway+will+not+be+opened%2C+Corps+of+Engineers+decides&rft.date=2023-09-27&rft_id=http%3A%2F%2Fwww.nola.com%2Fweather%2Findex.ssf%2F2016%2F01%2Fmorganza_floodway_will_not_be.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></span>
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</ol></div>
<h2><span class="mw-headline" id="External_sources">External sources</span></h2>
<style data-mw-deduplicate="TemplateStyles:r1134653256">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:#f9f9f9;display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style>
<div class="side-box-flex">
<div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, /upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span></div>
<div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Old_River_Control_Structure" class="extiw" title="commons:Category:Old River Control Structure">Old River Control Structure</a></span>.</div></div>
</div>
<ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1133582631"><cite id="CITEREFWeeks" class="citation web cs1">Weeks, John. <a rel="nofollow" class="external text" href="http://www.johnweeks.com/river_mississippi/pages/lmiss23.html">"Old River Control Structure"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2014-09-20</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Old+River+Control+Structure&rft.aulast=Weeks&rft.aufirst=John&rft_id=http%3A%2F%2Fwww.johnweeks.com%2Friver_mississippi%2Fpages%2Flmiss23.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOld+River+Control+Structure" class="Z3988"></span></li></ul>
<p><span class="geo-inline-hidden noexcerpt"><style data-mw-deduplicate="TemplateStyles:r1156832818">.mw-parser-output .geo-default,.mw-parser-output .geo-dms,.mw-parser-output .geo-dec{display:inline}.mw-parser-output .geo-nondefault,.mw-parser-output .geo-multi-punct,.mw-parser-output .geo-inline-hidden{display:none}.mw-parser-output .longitude,.mw-parser-output .latitude{white-space:nowrap}</style><span class="plainlinks nourlexpansion"><a class="external text" href="https://geohack.toolforge.org/geohack.php?pagename=Old_River_Control_Structure&params=31.0768_N_91.5979_W_region:US-LA_type:landmark"><span class="geo-default"><span class="geo-dms" title="Maps, aerial photos, and other data for this location"><span class="latitude">31°04′36″N</span> <span class="longitude">91°35′52″W</span></span></span><span class="geo-multi-punct"> / </span><span class="geo-nondefault"><span class="geo-dec" title="Maps, aerial photos, and other data for this location">31.0768°N 91.5979°W</span><span style="display:none"> / <span class="geo">31.0768; -91.5979</span></span></span></a></span></span>
</p></div>' |
Whether or not the change was made through a Tor exit node (tor_exit_node) | false |
Unix timestamp of change (timestamp) | '1696461625' |