An anabranch is a section of a river or stream that diverts from the main watercourse channel (or mainstem) and rejoins the mainstem downstream.

In the simplest case, an island or rock in the river creates a main course and an anabranch course; a more significant anabranch would diverge for a distance of several kilometres before rejoining.

River deltas branch into large numbers of courses, though these are not normally regarded as anabranches, as the net result is usually multiple discharge points rather than a rejoined unified flow.

Word usage and related terms

The term "anabranch", in its hydrological meaning, is rarely used outside of Australia.

Elsewhere, terms "distributary", or more colloquially "arm" or "channel" may be used for subsidiary streams that branch from the main stream; however, unlike the more specific "anabranch", these terms (especially "distributary" and "arm") do not necessarily imply that the branch will rejoin the main course later downstream. In the United States, the term braided river describes watercourses which are divided by small islands, but the term does not cover extended separation.


* In the Fraser River delta of British Columbia, Canada, North Arm Fraser River, Middle Arm Fraser River, and South Arm Fraser River each fall into Georgia Strait separately. On the other hand, Annacis Island splits (South Arm) Fraser River into the (main) Annievile Channel and the (smaller) Annacis Channel, which rejoin below the island.

* On the Darling River in New South Wales, the river divides south of Menindee for a hundred kilometres before rejoining. The anabranch contains flowing water only in wetter years.
* The Bahr el Zeraf in southern Sudan splits from the Bahr al Jabal section of the White Nile and flows for 240 km (150 mi), before rejoining the White Nile proper upriver from Malakal.

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Anabranch — An a*branch, n. [Anastomosing + branch.] A branch of a river that re[ e]nters, or anastomoses with, the main stream; also, less properly, a branch which loses itself in sandy soil. [Australia] [1913 Webster] Such branches of a river as after… …   The Collaborative International Dictionary of English

  • anabranch — [an′ə branch΄] n. [< ana(stomosing) branch] 1. a river branch that reenters the main stream 2. a river branch that becomes absorbed by sandy ground …   English World dictionary

  • anabranch — Billabong Bil la*bong , n. [Native name.] In Australia, a blind channel leading out from a river; sometimes called an {anabranch}. This is the sense of the word as used in the Public Works Department; but the term has also been locally applied to …   The Collaborative International Dictionary of English

  • anabranch — a diverging branch of a river which re enters the main stream …   Dictionary of ichthyology

  • anabranch — /an euh branch , brahnch /, n. a stream branching off from a river and rejoining it further downstream. [1825 35; short for anastomotic branch. See ANASTOMOSIS] * * * …   Universalium

  • anabranch — noun A diverging branch of a river, creek, or stream which re enters the main stream. See Also: anabranching …   Wiktionary

  • anabranch — n. anastomotic branch (stream which branches off of a river) …   English contemporary dictionary

  • anabranch — an·a·branch …   English syllables

  • anabranch — /ˈænəbræntʃ / (say anuhbranch) noun a branch of a river which leaves the main stream and enters it again further on. {shortened form of ana(stomosing) branch} …  

  • anabranch — n. esp. Austral. a stream that leaves a river and re enters it lower down. Etymology: ANASTOMOSE + BRANCH …   Useful english dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”