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Confluence of the Bhagirathi and Alaknanda Rivers to produce the Ganges at Devprayag, India
The same confluence viewed from upstream at a different time; note the swirl of sediment from the Alaknanda.

In geography, a confluence is the meeting of two or more bodies of water. Also known as a conflux,[1] it refers either to the point where a tributary joins a larger river, (main stem), or where two streams meet to become the source of a river of a new name, such as the confluence of the Monongahela and Allegheny rivers in Pittsburgh, Pennsylvania creating the Ohio River.

River confluences often reveal differences in color between the two streams, arising from the sediments they carry. Such color differences, which persist for some distance downstream, can be seen in several of the images for this article.

Since rivers often serve as political boundaries, confluences sometimes demarcate three abutting political entities, such as nations, states, or provinces, forming a tripoint. Various examples are found in the list below. A number of major cities, such as Lyon, Khartoum, and St. Louis, arose at confluences; further examples appear in the list.

Contents

Notable confluencesEdit

 
The White Nile and Blue Nile merge at Khartoum; satellite view

AfricaEdit

AsiaEdit

AustraliaEdit

 
The Main (brownish in color) flows into the Rhine south of Mainz.
 
The Mosel flows into the Rhine at Koblenz.

EuropeEdit

Rhine basin

  • The Main River flows into the Rhine just south of Mainz, in Germany.
  • The Mosel flows into the Rhine further north at Koblenz. The name "Koblenz" itself has its origin in the Latin name "Confluentes".

Danube basin

 
Confluence of the Danube (light blue) and the Morava (dark blue) in Devín on the border between Austria and Slovakia.
  • The Thaya flows into the Morava in a rural location near Hohenau an der March in Austria, forming the tripoint of Austria, Czechia, and Slovakia.
  • The Morava flows into the Danube at Devín, on the border between Slovakia and Austria.
  • Osijek, Croatia, is on the right bank of the river Drava 25 km upstream of its confluence with the Danube.
  • The Sava flows into the Danube at Belgrade, the capital of Serbia.
  • The confluence of the rivers Pivka and Rak is one of the largest subterranean confluences in Europe.[2]

Other

 
The Marne (left) flows into the Seine near Paris.

North AmericaEdit

 
The confluence of the Allegheny and Monongahela at Pittsburgh, forming the Ohio

Mississippi basin

Atlantic watersheds

 
The confluence of the Fraser and Thompson rivers

Pacific watersheds

 
The confluence of the Rio Negro (black) and the Rio Solimões (turbid) near Manaus, Brazil.

South AmericaEdit

Confluences not of two riversEdit

 
Confluence of canals
This simplified diagram shows how a section of the Industrial Canal in New Orleans also serves as the channel for the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal. At the bottom, a portion of the Intracoastal is also shown to be "confluent" with the Mississippi River.

Occasionally "confluence" is used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals[3] or a canal and a lake.[4] A one-mile (1.6 km) portion of the Industrial Canal in New Orleans accommodates the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal; therefore those three waterways are confluent there.

See alsoEdit

External linksEdit

  • [1] A collection of full-size, vivid photographs of confluences, most of them mentioned in the list above.

ReferencesEdit

  1. ^ "Conflux - Definition of conflux by Merriam-Webster". merriam-webster.com. 
  2. ^ Kogovšek, Janja; Petrič, Metka; Zupan Hajna, Nadja; Pipan, Tanja. "Planinska jama" [Planina Cave]. In Šmid Hribar, Mateja; Golež, Gregor; Podjed, Dan; Kladnik, Drago; Erhartič, Bojan; Pavlin, Primož; Ines, Jerele. Enciklopedija naravne in kulturne dediščine na Slovenskem [Encyclopedia of Natural and Cultural Heritage in Slovenia] (in Slovenian). Retrieved 17 May 2012. 
  3. ^ The U.S. Army Corps of Engineers refers to the confluence of the Assawoman Canal with the Bethany Loop Canal in Delaware. See: "CENAP-OP-R-Quarterly Report, 2004-05-12". Philadelphia Engineer District. Retrieved 2006-03-11. 
  4. ^ Engineers in New Orleans refer to the confluence of the 17th Street Canal and Lake Pontchartrain. See: "Interim Closure Structure at 17th St. Canal". Task Force Guardian. Archived from the original on 2006-06-25. Retrieved 2006-03-11.