Drainage Basin (Cambridge (CIE) IGCSE Geography)

The Drainage Basin Processes

Drainage basin

• A major part of the hydrological system, drainage basins drain all the water which lands on the Earth's surface

• A drainage basin is an open system

• Every drainage basin is unique and is different in shape and size, with different rock types, relief and land use

Drainage basin features

• All drainage basins have some features in common:

  • Watershed

    • This is the boundary between drainage basins

  • Source

    • The furthest point from the mouth where the river starts can be an upland lake, spring or glacier

  • Confluence

    • The place where two or more streams/rivers meet

  • Tributary

    • A stream or river flowing into a larger stream or river

  • Mouth

    • Where the rivers enter the sea/ocean or sometimes a lake

Channel network

• Every drainage basin is covered by a network of tributaries that connect to the main river channel. The number of tributaries in a drainage basin is referred to as the drainage density:

  • Drainage basins with lots of tributaries have a high drainage density

  • Drainage basins with few tributaries have a low drainage density