11. Water and change Flashcards
Groundwater
water found below the surface which is not combined chemically with any minerals present.
Aquifer
a permeable rock that will hold water and permit its passage.
Water-stressed area
place where water supply is below 1700 cubic metres per person per year.
Water-scarce area
place where water supply falls below 1000 cubic metres per person a year.
‘Green’ water
that part of total precipitation that is absorbed by soil and plants, then released back into the air.
‘Blue’ water
precipitation that collects in rivers, lakes, wetlands and as groundwater. It is available for human use before it evaporates or reaches the ocean.
Potable water
water that is free from impurities, pollution and bacteria, and is thus safe to drink.
Evapotranspiration
the combined processes of evaporation, sublimation and transpiration of the water from the Earth’s surface into the atmosphere.
Physical water scarcity
when physical access to water is limited.
Economic water scarcity
when a population does not have the necessary monetary means to utilise an adequate source of water.
‘Grey’ water
water that has already been used for one purpose, but can possibly be reused for another purpose.
Water table
the top of the water-saturated part of a permeable rock. During periods of very high rainfall the water table may extend into the soil and possibly reach the surface of the ground.
Virtual water
the amount of water that is used to produce food or any other item and is thus essentially ‘embedded’ in the item.
Water footprint
a person’s water footprint is the volume of fresh water the individual uses directly and in the production of the goods and services that person consumes.
Desalination
the conversion of salt water into fresh water by the extraction of dissolved solids.
