The Drainage Basin - Key Terms
Tributary
A small steam that joins the main river
Permeable
Allowing liquid to mass through
Drainage Basin
An area of land drained by a river and its tributaries
Watershed
An invisible line that determines the edge of the drainage basin (high land)
Impermeable
Not allowing liquid to mass through
Source
Start of the river (highest point)
Drainage Density
Stream length / Drainage basin area
Drainage Pattern
The ways is which land is drained by a river. They are determined by shape, height and geology of the land
High Drainage Density
Water drains more quickly to a river. This is because the ground is impermeable, so water drains by surface run off, This leads to many tributaries and a danger of floods
Low Drainage Density
Water drains more slowly to a river. This is because the ground is permeable, so water drains by infiltration and so through flow, base flow and ground water flow. This leads to less tributaries and a smaller danger of floods
Confluence
Where 2 rivers meet
River Channel
Where the river flows
Mouth
Where the river meets the sea/lake