What type of system is a drainage basin?
An open system (it has inputs, outputs, stores, and transfers).
Name the four key components of the drainage basin system.
- Inputs
- Outputs
- Stores
- Transfers
Give an example of how the drainage basin shows a relationship between inputs, outputs, stores, and transfers.
Rainfall (input) → intercepted by vegetation (store) → infiltrates into soil (transfer) → lost via evapotranspiration (output).
Name three inputs into the drainage basin system.
- Precipitation (rainfall)
- Snow
- Hail
Name two outputs from the drainage basin system.
- Evaporation
- Evapotranspiration
- Condensation
- Channel flow
List five main stores of water within the drainage basin system.
- Atmosphere (clouds)
- Vegetation (interception & roots)
- Surface (channel, lake)
- Soil
- Bedrock (groundwater store below water table)
What are the main transfers of water within the drainage basin system?
- Stemflow
- Throughfall
- Infiltration
- Overland flow/surface runoff (Hortonian & saturation-excess)
- Throughflow
- Percolation
- Groundwater flow/baseflow
How does drainage basin size and shape affect water movement?
It influences the speed and volume of runoff reaching the channel (e.g., circular basins have faster runoff).
Name two soil properties that affect infiltration and water movement.
- Porosity
- Permeability
How do rock types influence water movement?
Permeable rocks (e.g., limestone, chalk) increase infiltration and groundwater flow, while impermeable rocks (e.g., granite, clay) encourage surface runoff.
Give three climatic factors that influence water movement in the drainage basin.
- Precipitation type
- Duration and intensity
- Temperature
- Evapotranspiration
- Antecedent moisture
How can vegetation type affect water movement?
Dense vegetation increases interception and infiltration, reducing surface runoff.
How does land use affect water movement?
Urban areas with impermeable surfaces increase surface runoff and decrease infiltration.
What is an annual hydrograph used for?
Reading and interpreting variations in discharge through the year.
Name four factors that can cause seasonal variations in discharge.
- Precipitation type
- Duration
- Intensity
- Temperature
- Evapotranspiration
- Antecedent moisture
- Vegetation type
- Land use
What are the main components of a storm hydrograph?
- Rising limb
- Peak discharge
- Falling limb
- Lag time
- Amount and timing of precipitation
How does antecedent moisture affect a storm hydrograph?
If the soil is already saturated, lag time decreases, and peak discharge increases (flashier response).
How does urbanisation affect storm hydrographs?
It produces a steeper rising limb, shorter lag time, and higher peak discharge due to impermeable surfaces.
