Hydrological Cycle in a Drainage Basin
Geography: Cambridge International GCSE (2027 Exams), topic 1.6.1
Hydrological Cycle in a Drainage Basin
The hydrological cycle doesn't just work at a global level - this cycle also works in smaller, open systems such as in drainage basins. The main features of the drainage basin hydrological cycle are:
Inputs into drainage basins
- There are three types of precipitation that input into a drainage basin:
- Orographic - when air masses rise over mountains causing it to condense and rain.
- Frontal - when two air masses meet at an area of low pressure creating rain.
- Convectional - rainfall caused by water turning to water vapour due to solar radiation.
Outputs from drainage basins
- The water processes we identify as outputs in a drainage basin are:
- Evaporation - when water turns to water vapour and leaves the drainage basin.
- Transpiration - when water leaves plants through holes in their leaves.
- Channel flow - the volume of water that is flowing in a river channel.
Flows
- The drainage basin hydrological cycle includes the following water flows:
- Interception - when plants capture precipitation in their leaves.
- Infiltration - when precipitation enters into the soil.
- Direct runoff - when water from precipitation or snowmelt flows across the ground’s surface because the surface is impermeable i.e. tarmac.
More flows
- The following are also flows that happen in a drainage basin:
- Saturated overland flow - when the ground is full of water, resulting in runoff.
- Throughflow - the horizontal flow of water through soil/rock layers.
- Percolation - the vertical flow of water between soil and rock layers.
- Groundwater flow - the flow of water horizontally once it has reached the water table.
Test yourself on Hydrological Cycle in a Drainage Basin
Which of the following is a type of rainfall?
What are percolation, infiltration and runoff examples of?