Biała Lądecka, a right tributary of Nysa Kłodzka in Poland, located in the village of Bielice in Lower Silesia

A tributary is a stream or river which flows into a main stem (or parent) river. A tributary does not flow directly into a sea. Tributaries and the mainstem river serve to drain the surrounding drainage basin of its surface water and groundwater by leading the water out into an ocean or some other large body of water.

A confluence is where two or more bodies of water meet together, usually referring to the action of tributaries. An affluent is synonymous to the word 'tributary', being defined as a stream or river that simply flows into a larger one.^[1]

A parallel to tributaries is the distributary, a river that branches off of and flows away from the main stream.

[edit] Terminology

Walton Creek, a small tributary of the Lochsa River in northeastern Idaho, flowing slightly upstream of its confluence with a larger stream.

'Right tributary' and 'left tributary' (or 'right-bank tributary' and 'left-bank tributary') are terms stating the position of the tributary relative flow into the main river. These terms are defined from the perspective of looking downstream (in the direction the water current is going).

[edit] Ordering and enumeration

The 'Pfinz', a right tributary of the Rhine, located in Baden-Württemberg

In orography, tributaries are ordered from those nearest to the source of the river to 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 composed of two or more first order tributaries combining to form the second order tributary.

[edit] See also

Look up tributary, confluent, or affluent in Wiktionary, the free dictionary.

• Distributary

[edit] References