Tributary

A tributary is a river that flows into another, usually larger, river and is therefore tributary to it.

Main rivers, on the other hand, mostly reach the sea or otherwise end by drying up or evaporating , sometimes in terminal lakes .

Conceptual classification

Classification of waters

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station canals or sewers, but not canalized naturally created flowing waters) or waters that flow into lakes and thus withdrawn from a meaning comparison to be carried out directly in pairs are.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 .

Orohydrographic characteristics

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.

Nominal tributary	Discharge (MQ) [m³ / s]	Catchment area [km²]	Length [km]	Nominal main flow	Discharge (MQ) [m³ / s]	Catchment area [km²]	Length [km]	Ratio discharge [%]	Ratio EZG [%]	Ratio length [%]
Rüttebach	0.43	9.28	4.18	Wehra	0.10	2.28	2.65	430	407	158
Seenbach	1.29	96.5	18.3	ohm	0.40	28.3	16.9	325	341	108
Isel	39	1201	57.9	Outside	13.5	670.4	59.1	289	179	97
Spree	36	9858	375	Havel	15th	3399	168.1	240	290	223
Zschopau	23.8	1847	130	Freiberg Mulde	10.3	1138	100.6	231	162	129
Nagold	13.3	1145	90.4	Enz	6.5	328	44.3	204	349	204
Luvua (with Luapula and Chambeshi )	1274	296,600	1400	Lualaba ( Congo )	651	187,800	960	196	158	146
Rhume	16.5	1194	72.4	rope	9.2	995	83	179	120	87
Schwarza (in the Black Forest)	2.6	111	29.3	Schlucht	1.5	86	21.3	173	129	138
Guaviare	7400	166.170	1760	Orinoco	4750	58,000	850	156	287	207
Angara	4500	1,039,000	3500	Yenisei	2900	360,000	1970	155	289	178
lock	4.9	282.9	34.2	Werra	3.0	273.0	46.1	150	104	74
Itter	1.2	52.1	19.3	Diemel	0.8	39.0	16.2	150	134	119
Moldova	151	28,090	440	Elbe	101	13,748	279	150	204	158
Oker	12.1	1834	128	All	8.2	1720	119.6	149	107	108
Iller	70.9	2152	147	Danube	49	5430	303	145	40	49
rope	62.4	6512	281	All	43.4	7209	196	144	90	143
Ohio	7973	525.770	2102	Mississippi	5,865	1,847,188	4442	136	28	47
Eder	34.8	3361	176.1	Fulda	27.0	2997	175.4	129	112	100
Aare	563	17,779	288.2	Rhine	439	15,907	304.3	128	112	95
Araguaia	5507	384,800	2198	Tocantins	4527	305,551	1970	127	126	116
Regnitz	56.6	7523	162.1	Main	44.7	4416	142.8	127	170	114
Negroes	1.3	53.9	17.7	Dysentery	1.1	53.0	16.7	118	102	106
Hillebach		17.3	7.7	Dysentery		13.7	6.7		126	115
Flaz	7.9	194	22nd	Inn	6.8	196	27	116	99	81
Or (in the Harz)	6.3	385	56.8	Rhume	5.5	499.8	25.1	115	77	226
Doubs	176	7710	453	Saone	159	11,720	311	111	66	146
Inn	738	26,063	517	Danube	690	49,716	663	107	52	78
ohm	7.95	983.8	59.8	Lahn	8.83	651.7	58.8	90	151	102
Unstrut	30.2	6364.2	192	Saale	36.8	5097.2	158	82	125	122
Missouri	2380	1,371,010	4130	Mississippi	2920	434.220	1862	81	316	222
Warta	195	54,529	808	Or	325	53,752	629	70	101	128
Vaal	125	189,000	1250	Orange	220	89,000	1050	57	212	119
Irtysh	2960	1,673,470	4248	If	7200	1,016,000	3176	41	165	134
Darling	216	635.480	2844	Murray	524	323.310	1547	41	197	184

Individual evidence

1. ^ Friedrich Wilhelm: Hydrologie, Glaciologie , Georg Westermann Verlag, Braunschweig 1966, p. 54
2. ↑ ( Memorandum : "Brigach and Breg bring the Danube on the way.")
3. ↑ ^{a b c} 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".
4. ↑ Length about Sesto Bach
5. ↑ Mamdouh Shahin: Hydrology and water resources of Africa , Vol. 1, 2002, p. 342
6. ↑ length including tributary Oder; Rhume alone: ​​40.7 km
7. ↑ 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. ) 
8. ↑ 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 )
9. ↑ 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
10. ↑ Schwarmstedt gauge
11. ↑ ^{a b} Marklendorf gauge
12. ↑ ^{a b} 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
13. ↑ with Missouri / Jefferson, Mississippi alone: ​​2,172 km
14. ^ AG Scherrer: Scenarios for the extreme floods of the Rhine near Basel. Reinach 2004.
15. ↑ 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.
16. ↑ 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
17. ↑ 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%).
18. ↑ Lindau O level
19. ↑ Lindau R gauge
20. ^ With the upper reaches of the Jefferson River
21. ↑ ^{a b} calculated from the St. Louis level below the estuary
22. ↑ Determined from the level data Kietz (EZG), Eisenhüttenstadt and Hohensaaten (MQ)
23. ↑ 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.
24. ↑ 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.
25. ↑ Overview of sub-catchment areas and outflows , sub- catchment areas each of the Darling and the Murray totaled
26. ^ Australian Government: Geoscience Australia, data from Sept. 2008

Web links

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