Deferred tributary

A tributary is a stream or river which flows into the main river. A tributary does not flow directly into a sea. Tributaries and the main 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 deferred tributary is formed when tributaries in a flood plain may not be able to enter the main river because of raised levees on either bank of the river. They flow parallel to the main river for some distance before being able to enter it finally. Such tributeries are called deferred tributaries.

A confluence is when 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.

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

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


'Right tributary' and 'left tributary' are terms stating the relative positions of the tributary to the main river. These terms are applied from the perspective of looking downstream (in the direction the current of the water is flowing).

Also, there are names or numbers for tributaries. For example, there is the 'Pfinz', a right tributary of the Rhine River, located in Baden-Württemberg. In orography, tributaries are numbered 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.