Geography T1 - Hydrologic cycle

evaporation

• hydrological cycle starts with this, due to the heat of the sun

• water is converted from liquid to gas (water vapour)

• evaporation takes place at water surfaces like the sea and rivers, lakes and ponds on land.

transpiration

• plants take up liquid water from the soil and ‘breathe’ out into the atmosphere as water vapour

evapotranspiration

• the loss of moisture from the ground by evaporation from the water bodies and the soil PLUS transpiration from plants

condensation

• water vapour cools to become liquid in the form of minute water droplets: these can be seen in the atmosphere as clouds

precipitation

• the transfer of water (rain, hail, sleet, snow) from the atmosphere to land/sea surfaces

overland flow

• most precipitation that hits the ground moves due to gravity and eventually reaches a stream, river or lake.

• this is know as ‘run-off’ or ‘surface run-off’

infiltration

• the transfer of water downwards (gravity) through the soil and rock into the aquifer or groundwater store

• infiltration is defined as the downward entry of water into the soil or rock surface

percolation

• the transfer of water downwards (gravity) through the soil and rock into the aquifer or groundwater store

• the flow of water through soil and porous or fractured rock.

throughflow

• takes place between the ground surface and the top of the groundwater store

• water moves slowly due to gravity until it reaches a stream or river

groundwater flow

• this happens in the rocks of the aquifer and is the underground transfer of waters to rivers, lakes and seas.

the hydrological cycle

global movement of water between air, land and sea or circulation of water around the earth

the hydrological cycle 2

a closed system of linked processes so there are no external inputs or outputs

global cycle