A tributary,[1] or affluent,[2] is a stream or river that flows into a larger stream or main stem (or parent) river or a lake.[3] A tributary does not flow directly into a sea or ocean.[4] Tributaries and the main stem river drain the surrounding drainage basin of its surface water and groundwater, leading the water out into an ocean. The Irtysh is a chief tributary of the Ob river and is also the longest tributary river in the world with a length of 4,248 km (2,640 mi). The Madeira River is the largest tributary river by volume in the world with an average discharge of 31,200 m3/s (1.1 million cu ft/s).

The Nam Khan flows into the Mekong at Luang Prabang in Laos.

A confluence, where two or more bodies of water meet together, usually refers to the joining of tributaries.

The opposite to a tributary is a distributary, a river or stream that branches off from and flows away from the main stream.[5] Distributaries are most often found in river deltas.

Share this article:

This article uses material from the Wikipedia article Tributary, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.