Editing Distributary

{{Redirect|Branch river||Branch River (disambiguation)}}
{{more citations needed|date=May 2014}}
{{short description|Stream branching off from main stream channel}}
[[File:RMSDeltaNorth.jpg|thumb|[[Rhine–Meuse–Scheldt delta]], with the flow from right to left, showing several streams branching off from their main streams]]

A '''distributary''', or a '''distributary channel''' is a [[stream]] [[channel (geography)|channel]] that branches off and flows {{em|away from}} a main stream channel. It is the opposite of a ''[[tributary]]'', a stream that flows {{em|towards and into}} another stream or river. Distributaries are a result of [[river bifurcation]] and are often found where a river approaches a [[lake]] or an [[ocean]] and divides into distributary networks; as such they are a common feature of [[river delta]]s.<ref>{{cite journal |title=Modeling river delta formation |last1=Seybold |first1=Hansjörg |last2=Andrade Jr. |first2=José |last3=Hermann |first3=Hans |date=23 October 2007 |volume=103 |number=43 |doi=10.1073/pnas.0705265104 |journal=  Proceedings of the National Academy of Sciences|pages=16804–16809 |location=Boston |doi-access=free |pmid=17940031 |pmc=2040410 |arxiv=0711.3283 |bibcode=2007PNAS..10416804S }}</ref> They can also occur inland, on [[alluvial fan]]s, or where a tributary stream bifurcates as it nears its [[confluence]] with a larger stream. In some cases, a minor distributary can divert so much water from the main channel that it can later become the main route.

==Related terms==
Common terms to name individual river distributaries in [[English-speaking world|English-speaking countries]] are ''arm'' and ''channel''. These terms may refer to a distributary that does not rejoin the channel from which it has branched (e.g., the North, Middle, and South Arms of the [[Fraser River]], or the West Channel of the [[Mackenzie River]]), or to one that does (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]] such a branching river is called a ''[[braided river]]''.<ref name=BristowBest>{{cite journal |title=Braided rivers: perspectives and problems |first1=C. S. |last1=Bristow |first2=J. L. |last2=Best |journal=Geological Society, London, Special Publications |volume=75 |pages=1–11 |date=1 January 1993  |issue=1 |doi=10.1144/GSL.SP.1993.075.01.01|bibcode=1993GSLSP..75....1B |s2cid=129232374 }}</ref>

==North America==
[[File:Atchafalaya River.png|thumb|[[Atchafalaya River]]]]

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 does the Mississippi, over several decades the Atchafalaya has captured more and more of the Mississippi's flow, after the Mississippi meandered into the [[Red River of the South]]. The [[Old River Control Structure]], a [[dam]] which regulates the outflow from the Mississippi into the Atchafalaya, was completed by the [[United States Army Corps of Engineers|Army Corps of Engineers]] in 1963. The dam is intended to prevent the Atchafalaya from capturing the main flow of the Mississippi and stranding the ports of [[Baton Rouge]] and [[New Orleans]].<ref>[[John McPhee]], [[The Control of Nature]]</ref>

In [[British Columbia]], Canada, the [[Fraser River]] has numerous sloughs and side-channels which may be defined as distributaries. This river's final stretch has three main distributaries: the [[North Arm of the Fraser|North Arm]] and the [[South Arm of the Fraser|South Arm]], and a few smaller ones adjoining them.

Examples of inland distributaries:
* [[Teton River (Idaho)|Teton River]]—a tributary of [[Henrys Fork (Snake River)|Henrys Fork]] in [[Idaho]]—splits into two distributary channels, the North Fork and South Fork, which join Henrys Fork miles apart.
* [[Parting of the Waters]] National Landmark within Wyoming's [[Teton Wilderness]] on the [[Continental Divide]] where [[North Two Ocean Creek]] splits into two distributaries, Pacific Creek and Atlantic Creek, which ultimately flow into their respective oceans.
* [[Kings River (California)]] has deposited a large alluvial fan at the transition from its canyon in the [[Sierra Nevada (U.S.)|Sierra Nevada]] mountains to the flat [[Central Valley (California)|Central Valley]].  Distributaries flow north into the Pacific Ocean via the [[San Joaquin River]] and south into an [[endorheic basin]] surrounding [[Tulare Lake]].
* The [[Qu'Appelle River]], in [[Saskatchewan]] and [[Manitoba]], is a distributary of the [[South Saskatchewan River]]. Its flow is controlled by the [[Qu'Appelle River Dam]]. This dam forms the southern arm of [[Lake Diefenbaker]].

==South America==
The [[Casiquiare canal]] is an inland distributary of the upper [[Orinoco]], which flows southward into the [[Rio Negro (Amazon)|Rio Negro]], forming 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==
[[File:Maas_Delta1.jpg|thumb|right|250px|Satellite image of part of the [[Rhine–Meuse–Scheldt delta]]]]
*The [[IJssel]], the [[Waal (river)|Waal]] and the [[Nederrijn]] (Lower Rhine) are the three principal distributaries of the [[Rhine]]. These are formed by two separate bifurcations within the [[Rhine–Meuse–Scheldt delta]].
*The [[Akhtuba River]] is a major distributary of the [[Volga]]. The bifurcation occurs close to, but before, the [[Volga Delta]].
* The [[Tärendö River]] in northern [[Sweden]] is an '''inland distributary''', far from the mouth of the river. It begins at the [[Torne (Finnish and Swedish river)|Torne River]] and ends at the [[Kalix River]].
* The [[Little Danube]] in [[Slovakia]] branches off from the [[Danube]] near Bratislava, and flows into the [[Vah]] before rejoining the main river near [[Komárno]]. The area in the middle is the largest freshwater island in Europe.
* The [[Abbey River, Limerick|Abbey River]], [[Limerick]], in [[Ireland]] is a distributary arm of the [[River Shannon]]. It rejoins the Shannon to form an island upon which [[King John's Castle (Limerick)|King John's Castle]] is built. 
<!-- 
*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.
-->

==Asia==
===Eastern Asia===

The [[Huai River]] in China splits into three streams. The main stream passes through the Sanhe Sluice, goes out of the Sanhe river, and enters the [[Yangtze|Yangtze River]] through [[Baoying County|Baoying]] Lake and [[Gaoyou Lake]]. On the east bank of [[Hongze Lake]], another stream goes out of [[Hongze District|Gaoliangjian]] Gate and enters the [[Yellow Sea]] at the [[port]] of Bidan through Subei Guan'gai Zongqu, the main [[irrigation]] channel of Northern [[Jiangsu]]); its total length is 168 kilometers. The third stream leaves the Erhe lock on the northeast bank of Hongze Lake, passes the Huaishuhe River to the north of [[Lianyungang]] city, and flows into Haizhou Bay through the Hongkou.

===Southeast Asia===

The [[Tha Chin River]] and [[Noi River]] are distributaries of the [[Chao Phraya River]] in [[Thailand]], splitting off from the latter about 200 kilometers upstream from the [[Bay of Bangkok]].

The [[Brantas River]] in [[East Java]], [[Indonesia]], branches off into two distributaries, [[Mas River]], also known as Surabaya River, and [[Porong River]].<ref>{{cite conference |last1=Valiant |first1=Raymond |title=TANTANGAN DALAM PENGELOLAAN SUMBERDAYA AIR UNTUK MENCAPAI LINGKUNGAN LESTARI BERKELANJUTAN: POTRET DAERAH ALIRAN SUNGAI (DAS) BRANTAS |url=https://kmc-pengairan.bappenas.go.id/knowledge-management/download/340 |conference=Seminar Pekan DAS Brantas 2014  |publisher=Fakultas Teknik Universitas Brawijaya Malang |date=2014 |access-date=28 March 2024}}</ref>

The [[Red River (Asia)|Hong River]] in [[Northern Vietnam]] has notable distributaries such as the [[Đáy River|Day River]], [[Ninh Co River]] and the Luoc River. All of these rivers empty into the [[Gulf of Tonkin]].

===Indian Subcontinent===
[[Image:NearNannilam.jpg|thumb|A seasonal distributary of the [[Kaveri|Kaveri River]] on the Kaveri delta, near [[Nannilam]], [[India]]]]
* [[Kollidam River]] is a distributary of the [[Kaveri River]].
* [[Himalaya]]n rivers including Ganges, Brahmaputra and [[Indus]] plus many tributaries form inland distributaries over vast [[alluvial fans]] as they transition from the mountain region to the flat [[Indo-Gangetic Plain]].  These areas are highly flood-prone, for example the [[2008 Bihar flood]] on the [[Kosi River]].
* [[Padma River]] is the main distributary of the [[Ganges]] in [[Bangladesh]].
* [[Hoogli River]] is a [[Ganges]] distributary that flows through [[India]], whereas most of the Ganges-[[Brahmaputra]] complex enters the sea through [[Bangladesh]].
* [[Nara Canal|Nara River]] is a distributary of the [[Indus 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.

==Oceania==
[[File:Fly_River_Delta-txu-oclc-6552576-sc54-4.jpg|thumb|right|250px|Delta of Papua New Guinea's [[Fly River]]]]

===Australia===
A number of the rivers that flow inland from Australia's [[Great Dividing Range]] form distributaries, most of which flow only intermittently during times of high river levels and end in shallow lakes or simply peter out in the deserts. [[Yarriambiack Creek]], which flows from the [[Wimmera River]] into Lake Coorong, and Tyrrell Creek, which flows from the [[Avoca River]] into [[Lake Tyrrell]], are two distributaries in [[Victoria (Australia)|Victoria]]. The [[Narran River]] flows from the [[Balonne River]] in [[Queensland]] into [[Narran Lake]] in [[New South Wales]].

===Papua New Guinea===
Many of Papua New Guinea's major rivers flow into the [[Gulf of Papua]] through marshy, low-lying country, allowing for wide, many-branched deltas. These include the [[Fly River]], which splits into three major and several minor rivers close to its mouth. The [[Bamu River]] splits into several channels close to its mouth, among them the ''Bebea'', ''Bina'', ''Dibiri'', and ''Aramia''. The [[Kikori River]] also splits into a multitude of channels as it crosses the plains close to the Gulf of Papua. The [[Purari River]] splits into three major channels as it approaches its mouth.

===New Zealand===
New Zealand's second-longest river, the [[Clutha River]], splits into two arms, the ''[[Matau River|Matau]]'' and the ''[[Koua River|Koua]]'', some 10 kilometres from the South Island's Pacific Coast. A large island, [[Inch Clutha]], lies between the two arms. Many of the rivers crossing the [[Canterbury Plains]] in the central South Island are [[braided river]]s, and several of these split into separate branches before reaching the coast. Notable among these is the [[Rangitata River]], the two arms of which are separated by the low-lying [[Rangitata Island]].

==References==
{{reflist}}

=== Citations ===
* {{Cite journal |last1=Olariu |first1=Cornel |last2=Bhattacharya |first2=Janok P. |date=2006 |title=Terminal Distributary Channels and Delta Front Architecture of River-Dominated Delta Systems |url=http://eas.uh.edu/docs/geos/faculty-files/pdf/37_olariu_tdc_2006.pdf |journal=Journal of Sedimentary Research |publisher=Society for Sedimentary Geology |volume=76 |issue=2 |pages=212–233 |doi=10.2110/jsr.2006.026 |bibcode=2006JSedR..76..212O |access-date=December 10, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20151223195548/http://www.eas.uh.edu/docs/geos/faculty-files/pdf/37_Olariu_TDC_2006.pdf |archive-date=December 23, 2015 }}

{{Rivers, streams and springs}}

[[Category:Distributaries| ]]
[[Category:River bifurcations|*]]
[[Category:River morphology]]

[[ja:流路形状#派川]]