ANABRANCH
Etymology
Noun
anabranch (plural anabranches)
(hydrology, of a water channel) A diverging branch of a river, creek, or stream which re-enters the main stream.
Source: Wiktionary
An"a*branch, n. [Anastomosing + branch.]
Definition: A branch of a river that reënters, or anastomoses with, the
main stream; also, less properly, a branch which loses itself in
sandy soil. [Australia]
Such branches of a river as after separation reunite, I would term
anastomosing branches; or, if a word might be coined, anabranches,
and the islands they form branch islands.
Col. Jackson.
Source: Webster’s Unabridged Dictionary 1913 Edition