The Water Cycle and Water Insecurity Flashcards
Flux
the rate of flow between stores
Systems approach
Studying hydrological phenomena by looking at the balance of inputs and outputs, and how water is moved between stores by flows
Cryosphere
Areas of the Earth where water is frozen into snow and ice
Open system
- have transfers of energy and matter beyond and into the boundaries
Closed system
- have transfers of energy beyond the boundaries but not matter
dynamic equilibrium
when there is a balance between the inputs and outputs of a system, so matter stored in the system is constant
The global hydrological cycle
- closed system
- driven by solar energy (input) and gravitational potential energy
- the amount of water is constant on Earth and in the atmosphere
- proportions of different forms of water can change over time (solid, liquid and gas)
What flows/processes are there inside a hydrological system
- surface runoff
- groundwater flows
- channel flows
- precipitation
- evapotranspiration
- interception
- percolation
What stores are there inside a hydrological cycle
- atmosphere
- hydrosphere
- cryosphere
- biosphere
- lithosphere
Where is the Earth’s water stored?
- 96.5% stored in ocean
- 2.5% of the world’s water is surface and groundwater freshwater
- very little of this freshwater is accessible, with the majority of it stored as ice-caps
drainage basin system
- an area of land drained by a river and its tributaries
- is an open system so the amount of water in the drainage basin system varies over time
structures within a drainage basin
- main river
- tributaries
- watershed ( high land around the edge of the basin)
- catchment area (whole basin)
- source (start)
- mouth (end)
- confluence (two rivers join)
Blue water
water stored in rivers, streams or lakes and groundwater in liquid form (the visible part of the hydrological cycle)
Green water
Water stored in the soil and vegetation (the invisible part of the hydrological cycle)
Precipitation and the conditions required for it
- the movement of water in any form from the atmosphere to the ground
- air cooled to saturation point with a relative humidity of 100%
- condensation nuclei, such as dust particles, to facilitate the growth of droplets in clouds
- a temperature below dew point
Evaporation
the change of state of water from a liquid to a gas
Transpiration
the diffusion of water from vegetation into the atmosphere involving a change from a liquid to a gas
surface storage
the storage of water on the ground’s surface
soil storage
the storage of water in the soil
groundwater storage
the storage of water underground that has percolated through porous rocks
channel storage
the storage of water in streams or rivers
interception
water that is retained by vegetation surfaces from precipitation
infiltration
the movement of water from the ground to the soil
percolation
the transfer of water from the surface soil into the bedrock beneath