confluence

In geography, a confluence is the meeting of two or more bodies of water. It usually refers to the point where two streams flow together, merging into a single stream. It can be where a tributary joins a larger river, called the main stem, or where two streams meet to become the source of a river of a new name, such as the confluence of Bell Creek and Arroyo Calabasas, forming the Los Angeles River. In a broader sense, the merging of any two streams is a confluence.

The term is also used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals or a canal and a lake. A one-mile (1.6 km) portion of the Industrial Canal in New Orleans accommodates the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal; therefore those three waterways are confluent there.