River bifurcation

Bifurcation of the rabbit (left) and Else (right) near Melle

Bifurcation of Krollbach (left) and Schwarzwasserbach (right) in Hövelhof

A river bifurcation or river bifurcation is the branching (fork) of a flowing body of water in such a way that its water flows into two different river systems . The watershed is interrupted at the fork by the branching watercourse, so that part of the runoff passes from one catchment area to another. The word comes from Latin bi- "two" and furca "the fork".

In the English-speaking world, notwithstanding one of this importance, often each branch or fork riverbed in creeks , as well as the part runs a anastamosierenden river called "bifurcation".

Types of bifurcations

Permanent bifurcations

are active at practically every water level .

Periodic or ephemeral bifurcations

become active as an “overflow” only from a certain water level. For example, during floods in the Minnesota Lake District, the Mississippi system connects with the Red River and Lake Superior .

Underground bifurcations

occur in karst areas in phreatic or active vadose caves (water caves). A well-known example is the sinking of the Danube with an underground connection to the Aachtopf and thus to the catchment area of ​​the Rhine .

Pseudo-bifurcations

occur when stagnant water bodies such as swamps or lakes drain to several different river systems. Pseudo because here no actual current is split up, but a basin has several drains. Many pseudobifurcations in Central Europe owe their existence to glacial valleys : In the post-glacial period, the direction of the flat valley floors of the glacial valleys dictated the direction of flow for the waters. However, where the gradient was very low or where the glacial valley (due to postglacial processes) even had an apex, instead of flowing, standing water or bogs often formed. As soon as these drain into the glacial valley on both sides, there is a pseudobifurcation.

Diffluence

is called a bifurcation in glaciers  - in contrast to confluence , the confluence. In the flowing water currents within the glacier, the shapes of water caves also appear.

There are also numerous artificial bifurcations for supplying water to irrigation areas, cities and shipping canals as well as in power plant construction. Here, hydrographically significant amounts of water can be transported.

Examples

Bifurcations

• At the world's most important river bifurcation, the Brazo Casiquiare branches off 10 to 30% of the water from the upper Orinoco to the Rio Negro and thus to the Amazon system, depending on the water level . It is located in Venezuela , around two kilometers west of the village of Tamatama .
• The North Two Ocean Creek in Wyoming is divided on Two Ocean Pass in the Pacific Creek , which over the Snake River and Columbia River to the Pacific flows, and the Atlantic Creek , the over Yellowstone , Missouri and Mississippi River to the Gulf of Mexico and the Atlantic flows in.
• The Chiana connects the Arno with the Tiber system.
• The Torne älv , which flows from Sweden to Finland , loses half of its water through the Tärendöälven in the Kalixälven not far from the Swedish village of Junosuando .
• The Else branches off from the Hase at Melle - Gesmold and flows over the Werre into the Weser , while the Hase flows into the Ems . Both rivers ultimately end in the North Sea . Presumably an originally periodic bifurcation here was artificially expanded into a permanent bifurcation in the 15th or 16th century by a miller or by the owners of Gesmold Castle in order to be able to use the Else economically. As a result, one or the other arm was repeatedly locked during wars and quarrels.
• The confluence of the Datze (see below) in the Mecklenburg-Western Pomerania Landgraben , which flows from there westwards towards Peene and eastwards towards Zarow .
• The Krollbach in Hövelhof divides into the Krollbach and the Schwarzwasserbach . The Krollbach flows over the Haustenbach , the Lippe and the Rhine into the North Sea. The Schwarzwasserbach also flows over the Ems into the North Sea.
• The Mühlegraben near Blumberg forks on the edge of the reed in the apex of the Aitrach valley. From here the Aitrach flows into the Danube and the Schleifebächle into the Wutach Gorge , i.e. in the direction of the Rhine . The water network of the Blumberger Ried is also a pseudobifurcation (see below).

Bifurcation of the Nerodimka (Nerodimja) in Kosovo; with both directions of flow on signs: Deti i Zi ( Black Sea ) and Deti Egje ( Aegean Sea )

• The river Nerodimka (Nerodimja) ( Albanian also Nerodime , Serbian : Неродимка ) in Kosovo forks in the area of ​​the municipality of Ferizaj into one over the rivers Lepenc and Vardar of the Aegean Sea and into one over the Sitnica , the Ibar , the Morava and the Danube the part flowing into the Black Sea . An area of ​​13 hectares around the bifurcation is designated as a wildlife sanctuary. The bifurcation was created artificially in the 14th century. The artificial canal silted up more and more so that it hardly carried any more water. A few years ago this was corrected.
• In Rothenburg / Oberlausitz in Saxony, in the Geheege district, there is a bifurcation of a small creek without a name that flows out of the Biehainer peat cut. Part of the water reaches the North Sea via the Spree and Elbe, the other via the Neisse and Oder into the Baltic Sea.
• At the Zeinisjoch between Tyrol and Vorarlberg , the stream that flows down from the Fädner divides . The western half goes to the Ill and over the Rhine to the North Sea , the eastern half over the Trisanna and the Inn to the Danube and the Black Sea .
• The short creek Divide Creek splits on the southern slope of Kicking Horse Pass in Canada . The west arm drains over the Kicking Horse River  and Columbia River  into the Pacific, the east arm over Bow River and finally the Nelson River into Hudson Bay .

Pseudobifurcations

• Lakes:
  • The largest lake in the world that drains in two directions is Wollaston Lake in Saskatchewan , Canada . Spring from him
    • the Fond du Lac River , which drains to the Arctic Ocean and
    • the Cochrane River , which flows to Hudson Bay and thus to the Atlantic .
  • The Lappish lake Rostojávri has an outflow
    • through Norway into the European Arctic Ocean and
    • one through Sweden and Finland into the Bothnian Bay of the Baltic Sea .
  • The mountain lake Etang des Dougnes or Estany de les Dugues in the French Pyrenees drains
    • to the Têt in the Mediterranean at Perpignan and
    • via Angoustrine, Segre and Ebro to the Mediterranean off Spain.
  • The Selenter See in Schleswig-Holstein has two different drains to the Baltic Sea,
    • a direct north and
    • one via Salzau, Passader See and Hagener Au to the northwest.
  • The Müritz has
    • except for the original natural course through the Elde to the west to the Elbe
    • artificial to the east ( Alte Müritz-Havel-Wasserstraße or Bolter Canal ) that reach the Elbe via the Rhin .
  • Similarly, the Ruppiner See has different outflows:
    • the Old Rhin , which for its part bifurcates, on the one hand to flow eastwards via the Kremmener Rhin and Ruppiner Canal into the Oberhavel near Oranienburg and on the other hand to drain westwards through the Rhin Canal to the Unterhavel, and
    • the artificial Wustrauer Rhin, which also flows into the Rhin Canal.

In the Peene system there are many pseudobifurcations not only in glacial valleys .

• Waters with standing apex in glacial valleys :
  • The data flows
    • first south into the Tollense and thus via Peene into the Baltic Sea as well
    • northwards via Landgraben and Zarow also into the Baltic Sea.
  • The forked arms of the Kleiner Landgraben ultimately both reach the Baltic Sea via Tollense and Peene, but in different ways:
    • one leads to the south and flows directly into the Tollense,
    • the other goes to the north, in order to reach the Tollense from the east after joining the large ditch and the central ditch to the ditch .
  • Similarly, both ends of the Randow reach the Stettiner Haff in different ways ,
    • the north arm via Uecker ,
    • the southern arm via Catfish and Oder.
  • The drainage network of the red lynx near Müncheberg is draining
    • to the northeast through the Stöbber via Friedländer Strom, Wriezener Alte Oder and Oder into the Stettiner Haff of the Baltic Sea and
    • to the southeast through the Stobberbach via Löcknitz , Spree , Havel and Elbe to the North Sea .
  • The Ziese flows
    • on the one hand in the west near Greifswald in the Baltic Sea and
    • on the other hand in the east near Wolgast in the Peene river .
• Other wetlands:
  • The (upper and lower) reed in the Upper Aitrach Valley near Blumberg both drains
    • through the Schleifebächle to the west via Wutach and Rhine to the North Sea, as well
    • over the Aitrach to the east to the Danube and thus into the Black Sea .

Artificial bifurcations

• The artificial Schiffgraben drained westward into the Ilse and the Oker and Aller for Weser and eastward across the Great digging into the Bode and the Saale to the Elbe .
• The artificially created Altmühlüberleiter near Gunzenhausen in Bavaria guides the water from the Altmühl (Danube river system) to the Swabian Rezat (Rhine river system).
• Kaprun power plant in Austria: The worn out Pasterze on the Großglockner drains to the south, the power houses themselves to the north side of the Alps.
• Water from the upper reaches of the Unteralpreuss (Reuss → Rhine → North Sea) is fed via tunnels to Lago Ritóm , which is drained into the Adriatic through the Ticino (Ticino) and Po .
• The water dammed in Lac de l'Hongrin in the Vaudois Alps is diverted to Lake Geneva and thus flows into the Mediterranean, while the Hongrin inflow and outflow belong to the river system of the Rhine .
• Panama Canal , consisting of the Río Chagres , Lago Gatun system . This artificial pseudobifurcation is the most important shipping channel in the world.
• Río Fenix Grande is divided by the city of Perito Moreno . An artificial canal leads to the Río Deseado and thus to the Atlantic . The Río Fenix ​​Chico continues to Lago Buenos Aires / Lago General Carrera and thus over the Río Baker to the Pacific . The political background that led to the construction of this canal is interesting (see Río Deseado).

See also

• Watershed
• Muzzle arm
• Inland delta
• River delta

Web links

Commons : river bifurcation  - collection of images, videos and audio files

Wiktionary: Bifurcation  - explanations of meanings, word origins, synonyms, translations

Individual evidence

1. ↑ Herbert Louis : General Geomorphology. Walter de Gruyter Verlag, Berlin and New York, 4th edition 1979. ISBN 3 11 007103 7 . Section Covering watersheds, p. 317.
2. ↑ There are some interesting "holes" in the Continental Divide. Archived from the original on August 11, 2016 ; Retrieved October 17, 2009 . 
3. ↑ Regions and Rivers. Retrieved May 2, 2020 . 
4. ↑ Bifurcation of the rabbit :
   - Bifurcation , at Heimatverein Gesmold eV , on bifurkation.de
   - The history of the bifurcation in Gesmold , accessed on September 7, 2012, on bifurkation.de
   - The bifurcation of the rabbit in Melle-Gesmold , ... a hydrogeographic specialty in the association area , at the entertainment association No. 96 "Hase-Bever"
5. ↑ Bifurcation of the Nerodimka (Nerodimja) :
   - Hydrological heritage in the system of natural values ​​and its protection in Kosova. Retrieved September 7, 2012 .  (PDF; 716 kB)
   - Vlerat e trashëgimisë natyrore të Kosovës. (PDF; 7.6 MB) In: Agjensioni për Mbrojtjen e Mjedisit të Kosovës. Retrieved September 7, 2012 (English, with picture and map). - Ferizaj Municipality: Strategy for Local Economic Development 
   
6. ↑ Wasserscheide Geheege , on rothenburg-ol.de
7. ↑ Topographic map with the mountain lake Etang des Dougnes (Estany de les Dugues) , with both outflows, on geoportail.fr