high demand for resources
- Created by: vezting
- Created on: 28-03-16 20:08
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- high demand for resources
- Water in western USA
- facts
- western USA covers 60% of the USA
- Western USA has 40% of population
- western USA recieves only 20% of rainfall
- physical supply
- Low rainfall due to continental or mediterranean climate
- series of droughts and high evaporation from lakes behind dams
- excessive pumpin gfrom aqufiers and groundwater
- forestry has reduced evapo- transpiration so its drier
- human use
- rapid population growth especially city development Eg Los Angeles
- increased affluence Eg golf courses and swimming pools
- expansion of irrigated farming - 80% of the water goes to this
- large concerntrations of water-using industry Eg steel and chemical works
- 25% of water moved is lost in leakages
- outcomes
- dams on the colarado
- water transfers to the west via canals
- new sources of weater Eg desalinisation and iceburgs
- recycling water
- charging more for water
- more efficient uses Eg short flush toilets
- facts
- Tin and Copper in Cronwall
- facts
- 1840-60 they were largest suppliers of tin and copper in the world
- this lead to exhaustion of the resource
- physical supply
- vertical veins in granite- numerous but scattered
- ore metal content quite low 8% so produces a lot of waste
- veins went deep and some under sea and so needed pumping
- hard tough ore to mine
- found with valuable trace minerals Eg arsenic
- human use
- supplied much of the 19th century british industrialisation
- discovery of elecricity made copper very valuable
- by 1862 340 mines employed 50,000 people
- cheaper depositis found in malaysia in 1870's
- outcomes
- mines all closed by7 2005
- some mines are toursit attractions Eg Poldark mine
- mining towns such as Cambourne have suffered un employment and out-migration
- danger of hidden mine shafts
- facts
- Water in western USA
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