A tributary, or affluent, is a
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams are ...
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wa ...
that flows into a larger stream or
In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow.. ...
(or parent) river or a
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
. A tributary does not flow directly into a sea
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the worl ...
. Tributaries and the main stem river drain the surrounding drainage basin
of its surface water and
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...
, leading the water out into an ocean.
The Irtysh ( otk, 𐰼𐱅𐰾:𐰇𐰏𐰕𐰏, Ertis ügüzüg, mn, Эрчис мөрөн, ''Erchis mörön'', "erchleh", "twirl"; russian: Иртыш; kk, Ертіс, Ertis, ; Chinese: 额尔齐斯河, pinyin: ''É'ěrqísī hé'', Xiao'e ...
is a chief tributary of the Ob
river and is also the longest tributary river in the world with a length of .
The Madeira River ( pt, Rio Madeira, link=no ) is a major waterway in South America. It is estimated to be in length, while the Madeira-Mamoré is estimated near or in length depending on the measuring party and their methods. The Madeira is ...
is the largest tributary river by volume in the world with an average discharge of .
, where two or more bodies of water
meet, usually refers to the joining of tributaries.
The opposite to a tributary is a
A distributary, or a distributary channel, is a stream that branches off and flows away from a main stream channel. Distributaries are a common feature of river deltas. The phenomenon is known as river bifurcation. The opposite of a distributar ...
, a river or stream that branches off from and flows away from the main stream."opposite to a tributary"
PhysicalGeography.net, Michael Pidwirny & Scott Jones, 2009. Viewed 17 September 2012. Distributaries are most often found in
A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rare ...s.
"Right tributary", or "right-bank tributary", and "left tributary", or "left-bank tributary", are terms stating the orientation of the tributary relative to the flow of the main stem river. These terms are defined from the perspective of looking downstream (in the direction the
A current in a fluid is the magnitude and direction of flow within that fluid, such as a liquid or a gas.
Types of fluid currents include:
* Air current
* Boundary current
* Current (stream), a current in a river or stream
* Longshore current
* ... of the main stem is going). [Bisson, Peter and Wondzell, Steven]
An early tributary is a tributary that joins the main stem river closer to the main river's source than its end. Similarly, a "late tributary" joins the main river much further downstream, closer to the main river's end point.
In the U.S., where tributaries sometimes have the same name as the river into which they feed, they are called forks. These are typically designated by compass direction. For example, the
"Olympic Experimental State Forest Synthesis of Riparian Research and Monitoring"
United States Forest Service
The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency in ..., p. 15 (1 December 2009). American River
, name_etymology =
, image = American River CA.jpg
, image_size = 300
, image_caption = The American River at Folsom
, map = Americanrivermap.png
, map_size = 300
, map_caption ... in California receives flow from its North, Middle, and South forks. The Chicago River's North Branch has the East, West, and Middle Fork; the South Branch has its South Fork, and used to have a West Fork as well (now filled in).
Forks are sometimes designated as right or left. Here, the handedness"is from the point of view of an observer facing upstream. For instance, Steer Creek has a left tributary which is called Right Fork Steer Creek.
Ordering and enumeration
Tributaries are sometimes listed starting with those nearest to the source of the river and ending with those nearest to the mouth of the river. The Strahler stream order examines the arrangement of tributaries in a hierarchy of first, second, third and higher orders, with the first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary.
Another method is to list tributaries from mouth to source, in the form of a tree structure, stored as a ] tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are u ... data structure.
File:Amazonriverbasin basemap.png, The basin of the
The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile.
The headwaters of ... is a system made up of many tributary streams. The streams shown on the map besides the Amazon are tributaries of the Amazon.
File:Benuerivermap.png, The Benue River is fed by multiple tributaries originating in the Adamawa Plateau; many of the highest tributaries are seasonal streams. The Benue is itself a major tributary of the Niger
, official_languages =
, languages_type = National languages (itself a tributary of the Yangtze) and tributaries
File:Jialingrivermap.png, [Huai River
The Huai River (), formerly romanized as the Hwai, is a major river in China. It is located about midway between the Yellow River and Yangtze, the two longest rivers and largest drainage basins in China, and like them runs from west to east. ...](_blank) Jialing River
The Jialing River, formerly known by numerous other names, is a major tributary of the Yangtze River in the Sichuan Basin. It is named after the Jialing Valley in Feng County, Shaanxi through which it flows.
The Jialing River's most notable ... (itself a tributary of the Yangtze) and tributaries
File:Liaorivermap.png, The Liao River
The Liao River () is the principal river in southern Northeast China, and one of the seven main river systems in China. Its name derived from the Liao region, a historical name for southern Manchuria, from which the Liaoning province, Liaodong P ... is a much simpler example of a river basin with tributaries. The main tributaries noted on this map are the Hun River, Taizi River, Dongliao River, Xinkai River, Xiliao River, Xar Moron River and the Laoha River. The Xiliao River's tributaries are the Xar Moron and Laoha rivers.
File:Mekongbasin.jpg, The Mekong
The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annuall ... is a trans-boundary river, originating in the Tibetan Plateau. Its upper tributary river systems (e.g. ) are restricted to narrow gorges, but the tributaries that feed its lower reaches (e.g. the Mun River) cover larger areas.
File:Vermilion wabashrivermap.png, The water basin of the Wabash River
The Wabash River (French: Ouabache) is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed May 13, 2011 river that drains most of the state of Indiana in the United States. It flows fro ...; the other rivers (not including the Ohio River
The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illin ...) are tributaries of the Wabash River. The Vermillion River (and its forks
In cutlery or kitchenware, a fork (from la, furca ' pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods e ...) is a highlighted example of a tributary of the Wabash River. The Wabash River is also a tributary of the Ohio River, which in turn is a tributary of the Mississippi River
The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it ....
File:Yamunarivermap.jpg, The Yamuna is the second-largest tributary river of the Ganges and the longest tributary in India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so .... It flows almost parallel to the Ganges about its right bank for before merging with it at the Triveni Sangam
In Hindu tradition, Triveni Sangam is the confluence (Sanskrit: ''sangama'') of three rivers that is also a sacred place, with a bath here said to flush away all of one's sins and free one from the cycle of rebirth.
Triveni Sangam in Allah ..., Allahabad.