The Water Cycle and Water Insecurity Enquiry Question 1 - A Level Geography

The Water
Cycle and
Water
Insecurity
Enquiry Question 1: What are the processes operating within
the hydrological cycle from global to local scale?

, 5.1 The global hydrological cycle is of enormous importance to life on Earth.




In order to understand the operation of the hydrological cycle, a system approach is useful.
A system approach looks at the balance of inputs and outputs, and how water is moved
between stores by flows.
 Stores - reservoirs where water is held
 Fluxes - the rate of flow between the stores
 Processes - the physical mechanisms that drive the fluxes of water between the
stores
The hydrological system is a closed system because the amount of water on the Earth does
not fluctuate. While water changes forms as it flows through the hydrological cycle, there is
no significant input or output of eater from the planet. Rain, snow and ice that rain down
onto the planet eventually melt and evaporate, thereby replacing the water that
precipitated from the atmosphere.
Inputs Stores Fluxes/Flows Outputs
---  Lakes  Evaporation ---
 Oceans  Transpiration
 Atmosphere  Condensation
 Ground  Precipitation
 Rivers  Infiltration
 Cryosphere (ice)  Groundwater flow
 Vegetation  Surface runoff