Water Cycle EQ3 Key terms

• Desalination


  The process of converting saltwater to freshwater suitable for human consumption and industry.
• Eutrophication


  Excessive richness of nutrients in a lake or other body of water, frequently due to run-off from farming land, which causes a dense growth of plant life and death of animal life from a lack of oxygen.
• Fossil water


  Ancient, deep groundwater from former pluvial (wetter) periods.
• Agricultural drought

  A rainfall deficiency from meteorological drought that leads to deficiency of soil moisture and soil water availability, which has a knock on effect on plant growth and reduces biomass.
• Hard engineering

  The use of man-made, artificial structures to manage flooding or water supply.
• Desertification

  Land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities.
• Integrated water resource management (IWRM)

  A process that promotes the coordinated resources development and management of water and land to maximise economic and social profit equitably without compromising the sustainability of vital ecosystems.maximize resource
• Saltwater encroachment


  The movement of saltwater into freshwater aquifers due to sea level rise, storm surges and/or human abstraction of groundwater which lowers the water table.
• Economic water scarcity

  Occurs when water resources are available but there is insufficient human, institutional and financial capital to access the water in order to meet demand.
• Water budget

  The annual balance between inputs (precipitation) and outputs (evapotranspiration and channel flow) at a place.
• Water scarcity

  Occurs when renewable water resources are only between 500 and 1,000m3 per capita per year.
• River regime


  The annual variation in discharge or flow of a river at a particular point or gauging station, usually measured in cumecs.
• ENSO cycle

  Involves the movement of a mass of very warm water in the equatorial Pacific due to changes in the surface trade winds, atmospheric circulation and ocean currents. There are two phases- El Niño (warm water to the east) and La Niña (warm water to the extreme west).
• Treaty


  An agreement signed between states, recognised under international law.
• Systems approach

  Systems approaches study hydrological phenomena by looking at the balance of inputs and outputs, and how water is moved between stores and flows.
• Orographic rainfall

  Concentrated on the windward slopes and summits of mountains.
• Hydrological drought

  Associated with reduced stream flow and groundwater levels, which decrease because of reduced inputs of precipitation and continued high rates of evaporation. It results in reduced storage in lakes and reservoirs, often with marked salinization and poorer water quality.
• Transboundary water


  A water resource, including rivers, lakes and aquifers, that occupies a territory shared by more than one state.
• Water transfer

  Hard engineering projects, such as pipelines that divert water from drainage basins with surplus water to those with shortages.
• Inter-tropical convergence zone (ITCZ)


  A concentration of warm air that produces rainfall as part of a global circulation system (the Hadley cell). It moved north and south across the equator seasonally. Small shifts in location can cause drought.
• Drainage basin


  The catchment area from which a river system obtains its supply of water.
• Technological fix

  A human innovation using technology to solve a problem such as water supply issues.
• Meteorological drought

  Defined by shortfalls in precipitation as a result of short-term variability, or longer-term trends, which decrease the duration of the dry period.
• Drought?


  an extended period of deficient rainfall relative to the average rainfall for a region measured over a very long period.