Drainage Basin

• The term drainage basin refers to an area of land drained by a river and its tributaries (river system).
• It includes water found in the water table and surface run-off.
• The drainage basin is also known as catchment area among an assortment of terms.
• There is an imaginary line separating drainage basins called a watershed.
• Usually, the watershed is a ridge of high land for example mountains forming a boundary between two adjacent drainage basins.
• The point where a river begins is called the source. It is usually in the form of a lake or spring.
• A confluence  is the point where two rivers join.
• A tributary  is a stream or smaller river that joins a larger river.
• The mouth  is the point where a river enters the sea.

To access more topics go to the Geography Notes page.