Distributary
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224579224
2008-07-09T14:34:28Z
David Edgar
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[[WP:UNDO|Undid]] revision 224121806 by [[Special:Contributions/59.95.186.7|59.95.186.7]] ([[User talk:59.95.186.7|talk]]) vandalism - removal of entire lead section
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[[Image:NearNannilam.jpg|thumb|275px|A seasonal distributary of the [[Kaveri river]] on the Kaveri delta, near [[Nannilam]], [[India]].]]-->
A '''distributary''', or a '''distributary channel''', is a [[stream]] that branches off and flows away from a main stream channel. They are a common feature of [[river delta]]s. The phenomenon is known as [[river bifurcation]]. The opposite of a distributary is a [[tributary]]. Distributaries usually occur as a stream nears a [[lake]] or the [[ocean]], but they can occur inland as well, such as in an [[endorheic]] basin, or when a tributary stream bifurcates as it nears its confluence with a larger stream. In some cases, a minor distributary can "steal" so much water from the main channel that it can become the main route.
==Related terms==
Common terms to name individual river distributaries in [[English-speaking countries]] are ''arm'' and ''channel''. They may refer to a distributary that won't rejoin the channel it has branched off (e.g., the North, Middle, and South Arms of the [[Fraser River]], or the West Channel of the [[Mackenzie River]]), or one that will (e.g. Annacis Channel and Annieville Channel of the [[Fraser River]], separated by [[Annacis Island]]).
In Australia, the term [[anabranch]] is used to refer to a distributary that diverts from the main course of the river and rejoins it later. In [[North America]] an anabranch is called a braided stream.
==Distributaries in other countries==
===North America===
In [[Louisiana]], the [[Atchafalaya River]] is an important distributary of the [[Mississippi River]]. Because the Atchafalaya takes a steeper route to the [[Gulf of Mexico]] than the main channel, it has captured more and more of the Mississippi's flow over several decades, including capturing the [[Red River (Mississippi watershed)|Red River]], which was formerly a tributary of the Mississippi. The [[Old River Control Structure]], a [[dam]] which regulates the outflow from the Mississippi into the Atchafalaya, was completed in 1963 to prevent the Atchafalaya from capturing the main flow of the Mississippi and stranding the ports of [[Baton Rouge]] and [[New Orleans]].
An example of inland distributaries is the [[Teton River (Idaho)|Teton River]], a tributary of [[Henrys Fork (Snake River)|Henrys Fork]] in [[Idaho]], which splits into two distributary channels, the North Fork and South Fork, which join Henrys Fork miles apart.
[[North Two Ocean Creek]] splits into two distributaries, Pacific Creek and Atlantic Creek, which flow into the different oceans.
===South America===
The [[Casiquiare]] is a distributary of the upper [[Orinoco]], which flows southward into the [[Rio Negro (Amazon)|Rio Negro]] and forms a unique natural [[canal]] between the Orinoco and [[Amazon River|Amazon]] river systems. It is the largest river on the planet that links two major river systems.
===Europe===
*The [[IJssel]], the [[Waal (river)|Waal]] and the [[Nederrijn]] (Lower Rhine) are the three principal distributaries of the [[Rhine]].
*The [[Akhtuba River]] is a major distributary of the [[Volga]].
* The [[Tärendö River]] in northern [[Sweden]] is a real distributary, far from the mouth of the river. It begins at the [[Torne River]] and ends at the [[Kalix River]].
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*The [[Pripet River]] near the [[Belarus]]-[[Ukraine]] border may look on a map as a distributary that flows out of the [[Western Bug]] River into the [[Dnieper]], but this is not the case: there is simply an artificial canal between the two rivers, complete with locks etc.
*The [[River Ember]] in England Branches off from [[the River Mole]] Around Island Barn Resovoir.
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===Asia===
Other notable distributaries are the [[Kollidam River]], a distributary of the [[Kaveri River]], and the [[Hoogli River]], a distributary of the [[Ganges River]], both in [[India]]. Also, the [[Munneru]] is the distributary of the [[Krishna River]].
===Africa===
* The [[Nile River]] has two distributaries, the [[Rosetta]] and the [[Damietta]] branches. According to [[Pliny the Elder]] it had in ancient times seven distributaries (east to west):
** The Pelusiac
** The Tanitic
** The Mendesian
** The Phatnitic
** The Sebennytic
** The Bolbitine
** The Canopic
:See [[Nile Delta#History|History of the Nile Delta]].
* The [[Okavango River]] ends in many distributaries in a large inland delta called the [[Okavango Delta]]. It is an example of distributaries that do not flow into any other body of water.
==See also==
* [[Tributary]]
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[[Category:Rivers]]
[[cs:Říční rameno]]
[[de:Mündungsarm]]
[[fr:Défluent]]
[[mk:Растока]]
[[ja:分流]]
[[pl:Odnoga rzeki]]
[[fi:Suuhaara]]
[[ru:Речной рукав]]
[[zh:分流 (水文学)]]