T4 (Water) Definitions Flashcards
Hydrosphere
All the forms in which the Earth’s water can exist
Turnover Time
Time taken for water to completely replace itself in part of the system
Aquifer
Underground formation of permeable rock or loose material which stores groundwater
Precipitation
Conversion and transfer of moisture in the atmosphere to the land
Interception
Water that is caught and stored by vegetation
Through fall
Water that falls through gaps in the vegetation or drops from leaves, twigs or stems
Stemflow
Water that trickles along twigs and branches and finally down the main trunk
Evaporation
Conversion of solid and liquid precipitation to water vapour in the atmosphere
Transpiration
Process by which water vapour escapes from living plants, mainly from the leaves, and enters the atmosphere
EVT (Evapotranspiration)
Combined effects of evaporation and transpiration
Infiltration
Process by which water soaks into or is absorbed by the soil
Infiltration Capacity
Maximum rate at which rain can be absorbed by a soil in a given condition
Overland flow (Surface run-off)
Water that flows over the land’s surface
Condensation
Process by which vapour passes into a liquid form
Sublimation
Conversion of a solid into a vapour with no intermediate liquid state
Advection
Horizontal transfer of energy or matter
Freezing
Change of liquid water into solid ice, once temp falls below 0 degrees
Melting
Change from a solid ice to liquid water, when air temp rises above 0 degrees
Steam-flow or currents
Movement of water in channels, such as streams and rivers
Flooding
Covering of normally dry land by water
Irrigation
The addition of water to areas where there is insufficient water for adequate crop growth
Salinisation
(when groundwater levels close to surface) Capillary forces bring water to surface where evaporated, leaving behind soluble salts
Physical Water Scarcity
Shortages as demand exceeds supply
Water Stress
Demand exceeds availability by a serious amount during a certain time period or poor quality restricts its use
Water Harvesting
Making use of available water before it drains away or evaporates
Drip Irrigation
System of plastic tubes installed at / just below soil surface to deliver water to individual plants
Sustainable Yield
The rate of increase in natural capital that can be exploited without depleting the original stock or its potential for replenishment
Indicator Species
A species whose presence, absence or abundance can be used as an indicator of pollution
Biochemical Oxygen Demand (BOD)
A measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity
Anoxia
Oxygen starvation in the water
Biotic Index
A biotic index indirectly measures pollution by assaying the impact on species within the community according to their tolerance, diversity and relative abundance
Dead Zones
Occur when there is not enough oxygen to support marine life