Topography

Topography

The Colorado River at Horseshoe Bend, Arizona

The Porvoo River (Porvoonjoki) in the medieval town of Porvoo, Finland
A river begins at a source (or more often several sources), follows a path called a course and ends at a mouth or mouths. The water in a river is usually confined to a channel, made up of a stream bed between banks. In larger rivers there is often also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be very wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in urban areas where the floodplain of a river channel can become greatly developed by housing and industry.

Rivers can flow down mountains, through valleys (depressions) or along plains, and can create canyons or gorges.

The term upriver (or upstream) refers to the direction towards the source of the river, i.e. against the direction of flow. Likewise, the term downriver (or downstream) describes the direction towards the mouth of the river, in which the current flows.

The term left bank refers to the left bank in the direction of flow, right bank to the right.