the hydrosphere Flashcards
how might the global demand for water increase?
increase in population
-increase in per capita and increased affluence.
-increased irrigation.
-industrialization e.g paper making.
why cant a resevoirs importance be predicted from its quantity.
can be abundant but be transferred slowly
how do you calculate residence time
volume of water /mean transfer rate
what human activities impact the hydro logical cycle?
deforestation.
-agriculture
-urban development (impermeable surfaces)
global climate change
-water abstraction
what are the environmental effects on resevoirs
-habitat change
-wildlife barriers e.g for fish.
-river regime downstream of dams.
-sedimentation
-microclimates- high heat capacity of water reduces temperature fluctuations.
name an over exploted river
River nile- as populations grow and countries develop, demand for water increases which could cause conflict.
what are three features of aquifers-
porous-chalk and limestone are porous so form aquifers.
-permability-need to be permeable.
-associated geological stuctures-rock below must be impermeble but some rock above must be permeable to allow aquifer recharge.
aquifer recharge
humans are abstracting faster than rate of recharge.
what are impacts of over exploited aquifers
changes in surface hydrology-lowered water table-stopping flow of water to wetland.
-ecological impacts-water table lowered, plants may die and aquatic/ semi aquatic organisms die.
-salt water incursion-water table may be slightly higher than sea water, salt water contaminates freshwater making it unsuitable for irrigation.
name an example of an over exploited aquifer-
Malta -many of the islands aquifers have been contaminated by industrial/agricultural waste or have been over exploited-salt water incursion has occurred .
desalination is now required which is expensive.
exploitation of new sources of water
rainwater collection
-rivers
-resevoirs
-estuary barrages -created by placing a dam across an estuary where a river meets the sea.
-seawater
what factors need to be considered when selecting a reservoir site
topography-a small dam should still hold lots of water.
-geology.
-catchment area.
-water supply.
-pollution risk.
-sedimentation
-infrastructure.
-existing land use and conflicts.
what is an inter basin transfer
canal and pipe systems to transfer water for areas of surplus to shortage.
sustainable managemnt strategies of water
-artificial recharge of aquifers in seasons.
-river-regulation resevoirs.
-inter basin transfers
-unexploited aquifer.
-afforestaion
-water conservation
-low volume appliances, irrigation.
-greywater
-pollution control.
-reduced wastage e.g water meters.
what is aeration in water treatment processes
ensure a high dissolved oxygen content
-anaerobic decay may cause hydrogen sulfide with makes the water smell bad.
aeration removes dissolved metals that are toxic.
