A tributary is a river that flows into another, usually larger, river and is therefore tributary to it.
The term tributary in the described sense is largely unambiguous in the colloquial language (the tributary is also a tributary in hydrological and geographic usage). However, some distinctions from neighboring terms are less obvious.
The term inflow is more unspecific and also includes a little more in the geographical part of its meaning: Among other things, artificial channels such as canals (meaning power station canals or sewers, but not canalized naturally created flowing waters) or waters that flow into lakes and thus withdrawn from a meaning comparison to be carried out directly in pairs are.
The term inflow also includes non-linearly inflowing water, such as groundwater or extensive inflowing water after heavy rain (up to stratified floods in alternating humid climates).
In the geographical context, side stream is often used to describe the smaller part of the river that flows around a river island . The term does not refer to river junctions , but to temporary or permanent river branches . The terms tributary or river arm are used in a similar sense .
In some cases one speaks of two source rivers without an apparently clear main river. They then unite to form a river with a different name, as in the example of Fulda and Werra , which unite to form the Weser , or both have the later names with additions such as Vorderrhein and Hinterrhein or Weißer Main and Roter Main .
The distinction between terms makes it clear that the lemma tributary describes only one of many elements of a river system .
A simple systematization differentiates between direct tributaries of a main river and indirect tributaries that themselves flow into a tributary. The Isar, for example, is a direct tributary of the Danube . The Amper in turn is a direct tributary of the Isar and thus a second-order tributary of the Danube or its indirect tributary. There are several approaches to systematize the sequence of flowing watercourses flowing into one another from the source to the end of the main river with increasing flow order numbers . This results in tributaries of different orders.
The direction of the mouth of a tributary is given in relation to the direction of flow of the main river. One differentiates (always looking downstream) orographically right and left tributaries. For example, the Neckar flows orographically from the right into the Rhine and the Moselle from the left.
The orohydrografische consideration of a river system is not uncommon in the determination of the main Quellastes and the hierarchy of the tributaries to different results than suggested by the historically grown river names. Nevertheless, the names that have evolved over time usually also have an effect on the flow order numbers.
Naming of main and tributaries
When two rivers meet, the smaller one usually flows as a tributary into the larger river, which retains its name as the main river. It is not, however, bindingly defined which measure determines the size of the river. The historically grown naming has usually allowed the apparently larger river to retain its name. The water flow is therefore usually used to determine the main flow. Occasionally, for example when the volume of the rivers is not known or not obvious, the length of the river or the catchment area, both roughly determinable from topographic maps , are used.
In ambiguous cases, it is not uncommon for none of the rivers to carry the name further. A well-known example of a new river name from the mouth is the Weser , which arises from the longer Werra and the more water-rich Fulda . What is interesting about this example is that the Werra and Weser were once named as a river ( Wisahara / Visarius ). Other examples are Marañón (more watery) and Ucayali (longer), from which the Amazon emerges. The Rednitz (longer with the Franconian Rezat) and the Pegnitz form the Regnitz near Fürth . The Brigach and the water-rich and longer Breg bring in Donaueschingen , the Danube feeder path.
Tributaries can sometimes be longer than the richer main river or have a larger catchment area. In the first case, the reason can be a narrow catchment area or, in the other case, a lower mean discharge from the catchment area.
Nominal tributaries as main hydrological rivers
There are also tributaries that carry more water at the mouth than the nominal main river. They are thus part of the main flow path in a river system, i.e. the main river from a hydrological point of view. Many of these apparent tributaries also exceed the main river in terms of length or size of the catchment area.
Common reasons why the smaller of the two rivers is allowed to bear the name of the merged river are:
- The nominal main river has the same direction of flow as below the confluence (examples are Danube and Iller or Rhine and Aare ).
- The nominal main river follows a scenically more distinctive or spatially more significant depression (example: Danube and Inn , Orinoco and Guaviare ).
- The valley of the nominal main river is longer or more densely populated because it is more fertile, more spacious or more easily accessible (example: Elbe and Moldau ).
- The nominal tributary has its source in a different cultural area than the rest of the river system.
The following is a sortable table of tributaries, which should be addressed as main rivers at their mouths according to aquatic characteristics. In the basic setting, the table is arranged according to the discharge ratio (column 9). The parameters runoff , catchment area and length relate to the place immediately above the mouth.
[m³ / s]
[m³ / s]
|Luvua (with Luapula and Chambeshi )||1274||296,600||1400||Lualaba ( Congo )||651||187,800||960||196||158||146|
|Schwarza (in the Black Forest)||2.6||111||29.3||Schlucht||1.5||86||21.3||173||129||138|
|Or (in the Harz)||6.3||385||56.8||Rhume||5.5||499.8||25.1||115||77||226|
- Friedrich Wilhelm: Hydrologie, Glaciologie , Georg Westermann Verlag, Braunschweig 1966, p. 54
- ( Memorandum : "Brigach and Breg bring the Danube on the way.")
- The quotient of the value of the tributary by that of the main river above the mouth was calculated and multiplied by 100 - "100" would mean "tie".
- Length about Sesto Bach
- Mamdouh Shahin: Hydrology and water resources of Africa , Vol. 1, 2002, p. 342
- length including tributary Oder; Rhume alone: 40.7 km
- According to investigations for a hydrological simulation, doctoral thesis by Klaus Stephan, Bonn 2003 ( abstract and PDF download ( memento of the original dated November 2, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. and archive link according to the instructions and then remove this note. )
- Gustavo Silva León: La cuenca del río Orinoco: visión hidrográfica y balance hídrico (Revista Geográfica Venezolana, Vol. 46 (1) 2005, 75-108; PDF; 1.4 MB), on p. 100, table on the discharge balance )
- Length of Angara over the Tuul - Orkhon - Selenga flow path , length of the Yenisei with Little Yenisei including Shishchid gol above the lake Dood Nuur ; Outflow Jenissej derived from the levels Yeniseysk and Tatarka
- Schwarmstedt gauge
- Marklendorf gauge
- level Thebes, Global Runoff Data Center (2008): Long-Term Mean Monthly Discharges and Annual Characteristics of GRDC Station / Global Runoff Data Center. Koblenz, Federal Institute for Hydrology (BfG), 2009
- with Missouri / Jefferson, Mississippi alone: 2,172 km
- AG Scherrer: Scenarios for the extreme floods of the Rhine near Basel. Reinach 2004.
- Vorderrhein with Rein da Medels or Rein da Medels: 75.1 km, Alpine Rhine: 85.7 km, Lake Constance to the beginning of the Rhine kilometer in Constance: 41.0 km ( Rhine Museum, Koblenz ), Constance to Aare- Estuary: 102.5 km.
- Ministério do Meio Ambiente, Secretaria de Recursos Hídricos: Caderno da Região Hidrográfica do Tocantins-Araguaia. Brasília, 2006, 132 p. ISBN 85-7738-066-1 . (Quadro 1: Sub-regiões Hidrográfi cas do Tocantins-Araguaia e Respectivas Áreas e Vazões, p.22) PDF
- The relocation of the Flaz barrel in 2004 affected all values. Above the mouth, the Flaz was a good 2 km longer, the Inn almost 3 km. The catchment area of the Flaz grew by 2.6 km² (1.3%), that of the Inn by 7.6 km² (4.0%).
- Lindau O level
- Lindau R gauge
- With the upper reaches of the Jefferson River
- calculated from the St. Louis level below the estuary
- Determined from the level data Kietz (EZG), Eisenhüttenstadt and Hohensaaten (MQ)
- The length data for Vaal and Oranje vary greatly, but a difference of 200 kilometers is evident and is also confirmed by aerial measurements (google earth). However, this results in 1,450 km for the Vaal and 1,240 km for the Upper Orange.
- On the Hanti Mansiysk level value (Global Runoff Data Center (2008): Long-Term Mean Monthly Discharges and Annual Characteristics of GRDC Station / Global Runoff Data Center. Koblenz, Bundesanstalt für Gewässerkunde (BfG), 2009), the discharge of the remaining catchment area was determined (from the intermediate catchment area of the Hanti-Mansiysk , Prochorkino and Belogore gauges ) and added to it.
- Overview of sub-catchment areas and outflows , sub- catchment areas each of the Darling and the Murray totaled
- Australian Government: Geoscience Australia, data from Sept. 2008