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.
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:
- Inputs: How water is introduced into the The area of land that is drained by a river and its tributaries.. This is known as An input where water is introduced to the drainage basin system..
- Stores: How water is stored or held for a period of time within the drainage basin system - When water is absorbed and collected by vegetation (store). (by vegetation), soil moisture, The total volume of water held on the Earth's surface. (lakes), groundwater.
- Transfers: A process or flow of water from one place to another in the drainage basin system - Water moves across the surface of the earth becoming a stream, tributary or river (transfer)., Water soaks or filters into the soil (transfer)., Water moved from the soil into the spaces (pores) in the rock (transfer)., Water moves downhill through the soil (transfer)., When water is able to move slowly through the soil and porous rocks to move back towards the sea (transfer)..
- Outputs: How the water is released either back to the sea or back into the atmosphere - river discharge, Water vapour is evaporated from the trunk and the leaves of trees and other vegetation, back into the atmosphere. .
The drainage basin system
The dividing lines of mountain ranges are known as watersheds, and the areas between them are called drainage basins.