# What's the opposite of a tributary? **URL:** \ **Category:** Factual Questions\ **Created:** [November 13, 2003, 7:41pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076 "2003-11-13T19:41:04Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [November 13, 2003, 7:41pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/1 "2003-11-13T19:41:04Z")
What do you call a small river that branches off from a bigger one? ---
**Author:** ![Bongmaster](https://avatars.discourse-cdn.com/v4/letter/b/6a8cbe/32.png) [@Bongmaster](https://boards.straightdope.com/u/Bongmaster)\ **Post date:** [November 13, 2003, 7:47pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/2 "2003-11-13T19:47:26Z")
A stream, creek, run, or river; I’m not sure that there is such a thing as a “reverse tributary.” ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 13, 2003, 8:20pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/3 "2003-11-13T20:20:29Z")
Except in the cases of a river delta or to go around an island, rivers rarely split into two streams. Because of that, there’s no real need for a special term for the phenomenon. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 14, 2003, 12:05am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/4 "2003-11-14T00:05:03Z")
The closest that I can think of is anabranch, the term for a river channel that splits off the main trunk but that rejoins it at some later point. As dtilque points out, it’s almost unheard of (well I’ve never heard of it) for a stream to leave a river and never rejoin it. It could really only possibly occur if a mountain or similar cause the river to split very close to the coast so that the there were two river mouths produced. ---
**Author:** ![Aankh](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@Aankh](https://boards.straightdope.com/u/Aankh)\ **Post date:** [November 14, 2003, 12:13am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/5 "2003-11-14T00:13:18Z")
Back in school, we learned in geometry that a small river branching off from a bigger one is a **distributary**. [Cite](http://en.wikipedia.org/wiki/Distributary). ---
**Author:** ![Aankh](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@Aankh](https://boards.straightdope.com/u/Aankh)\ **Post date:** [November 14, 2003, 12:14am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/6 "2003-11-14T00:14:26Z")
Ya that’s right…my geometry teacher loved teaching us topography. :smack: ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 14, 2003, 12:20am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/7 "2003-11-14T00:20:57Z")
Distributaries, and they are almost always associated with deltas. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [November 14, 2003, 2:15am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/8 "2003-11-14T02:15:05Z")
If there was a word, I knew the Teeming Millions would know it. 🙂 Distributary. Awesome. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 14, 2003, 2:55am UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/9 "2003-11-14T02:55:51Z")
There is at least one river that splits without rejoining: the Orinoco in South America. The main channel goes north to the Caribbean while part of it goes south and ultimately drains into the Atlantic via the Amazon. This may be a unique case in the entire world. ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 14, 2003, 1:06pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/10 "2003-11-14T13:06:04Z")
Nope, not unique: what you’ve just described is a distributary on the Orinoco Delta. Although it is pretty cool that one distributary drains into the Carribean and the rest drain into the Atlantic, it is just a delta distributary. Here’s a [map](http://www.discovervenezuela.com/images/map.gif) of Venezuela that shows the Orinoco Delta. And you can click on [this map](http://www.think-venezuela.net/english/p_delta.htm#map) of the Orinoco Delta to see a better close-up view. ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [November 14, 2003, 2:37pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/11 "2003-11-14T14:37:18Z")
> [@](#): > > As dtilque points out, it’s almost unheard of (well I’ve never heard of it) for a stream to leave a river and never rejoin it. It could really only possibly occur if a mountain or similar cause the river to split very close to the coast so that the there were two river mouths produced. In the Canadian Rockies, on the border between BC and Alberta, there’s a creek that splits into two creeks. One flows west to the Pacific, while the other flows east to reach Hudson Bay. The location of the split is pretty far from both oceans. [Cite](http://www.fairmont.com/FA/en/CDA/Home/Hotels/AboutHotel/CDExploreAreaDetail/0,2995,code%25255Ftype%253DSITE%2526category%25255Ftype%253Dpt%25255Fof%25255Fint%2526property%25255Fseq%253D100105,00.html) (scroll down to the paragraph on the Continental Divide.) ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [November 14, 2003, 3:00pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/12 "2003-11-14T15:00:29Z")
> [@](#): > > \*Originally posted by Pantellerite \* > Here’s a [map](http://www.discovervenezuela.com/images/map.gif) of Venezuela that shows the Orinoco Delta. And you can click on [this map](http://www.think-venezuela.net/english/p_delta.htm#map) of the Orinoco Delta to see a better close-up view. The delta doesn’t enter into it. The bifurcation is much more upstream, where the Casiquiare canal branches off to join the Rio Negro and eventually tha Amazon river. Here’s a [much better map.](http://www.stangrist.com/humboldtmap.jpg) ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 14, 2003, 5:12pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/13 "2003-11-14T17:12:44Z")
Thanks, **Floater**! Very odd. Maybe it is unique after all. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [November 14, 2003, 6:16pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/14 "2003-11-14T18:16:16Z")
The Pearl River in southern Mississippi also splits into two distributaries: the east fork and the west fork. ---
**Author:** ![Richard](https://avatars.discourse-cdn.com/v4/letter/r/f0a364/32.png) [@Richard](https://boards.straightdope.com/u/Richard)\ **Post date:** [November 14, 2003, 6:44pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/15 "2003-11-14T18:44:38Z")
The Rhine River splits into three or more pieces through Holland and Belgium. Of course you could say that the whole area is the Rhine delta, but that’s a pretty large area. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [November 14, 2003, 7:40pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/16 "2003-11-14T19:40:23Z")
> [@](#): > > \*Originally posted by Floater \* > \*\*The delta doesn’t enter into it. The bifurcation is much more upstream, where the Casiquiare canal branches off to join the Rio Negro and eventually tha Amazon river. Here’s a [much better map.](http://www.stangrist.com/humboldtmap.jpg) \*\* That is fascinating, but why is it called a “canal”? Wikipedia refers to it as a “natural canal”, which is oxymoronic. From the AHD, a canal is: > [@](#): > > An **artificial** waterway or **artificially improved river** used for travel, shipping, or irrigation. Bolding mine. The feature is natural, and from the description of it, pretty much non-navigable. ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [November 14, 2003, 8:21pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/17 "2003-11-14T20:21:41Z")
> [@](#): > > \*Originally posted by yabob \* > \*\*That is fascinating, but why is it called a “canal”? Wikipedia refers to it as a “natural canal”, which is oxymoronic. The feature is natural, and from the description of it, pretty much non-navigable. \*\* It could be that the name is straight from the Spanish. “Canal” can mean _channel_ in addition to _canal_. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [November 14, 2003, 8:22pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/18 "2003-11-14T20:22:47Z")
> [@](#): > > \*Originally posted by dtilque \* > \*\*There is at least one river that splits without rejoining: the Orinoco in South America. The main channel goes north to the Caribbean while part of it goes south and ultimately drains into the Atlantic via the Amazon. This may be a unique case in the entire world. \*\* So then that would be the “Orinoco Flow”? Any Enya fans? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 14, 2003, 8:59pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/19 "2003-11-14T20:59:41Z")
> [@](#): > > \*Originally posted by Richard \* > The Rhine River splits into three or more pieces through Holland and Belgium. Of course you could say that the whole area is the Rhine delta, but that’s a pretty large area. Although it’s probably smaller than the Amazon delta. But then the Amazon has many times the flow of the Rhine, so I guess that’s to be expected. From what I understand, about 30% or so of the Mississippi River flows out the Atchafalaya River. In fact, if it weren’t for heroic efforts by the Army Corp of Engineers, the Atchafalaya would now be the main channel. ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [November 14, 2003, 9:26pm UTC](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076/20 "2003-11-14T21:26:41Z")
Read John McPhee’s [The Control Of Nature](http://www.aaabooksearch.com/Reviews/0374522596) for an excellent history of that occurence. [Next page](https://boards.straightdope.com/t/whats-the-opposite-of-a-tributary/213076.md?page=2)