Drainage basins

Drainage basins refer to the area of land drained by a major river and its tributaries. All rivers flow from the source (often in the mountains) to the mouth (the sea). The drainage basin is regarded as a closed system because water never leaves. Instead, it is recycled from one state to another.

Processes of a river drainage basin

The hydrological cycle within a drainage basin is different in that it is a closed system. Input will vary. Water transfer and storage will also vary from one drainage basin to another.

Ways in which water moves through a drainage basin.A diagram showing the ways in which water moves through a drainage basin

The video below shows an illustrated explanation of the hydrological cycle, introducing key terms.

The drainage basin system

A major component of the water cycle is the drainage basin system.

There are many inter-relationships within this system:

Illustration showing storage in the drainage basin.The drainage basin system

The dividing lines of mountain ranges are known as watersheds, and the areas between them are called drainage basins.