water

• what global areas experience water surplus?

  large parts of north america, central europe and parts of south-east asia
• what global areas experience water deficit?

  The Middle East, Northern Africa and Australia.
• what is water surplus?

  when the supply of water is greater than the demand
• what is water deficit?

  what the demand for water is greater than the supply
• areas of water surplus globally are generally located in...

  areas/bands of low pressure where warm moist air rises and so more air evaporates and condenses and more percipitation is formed.
• areas of water deficit globally are generally located in...

  areas/bands of high pressure where cold air sinks towards the ground resulting in little to no evaporation and so less condensation and less percipitation is being formed
• what is water security?

  water security occurs when people have reliable and affordable access to clean water to sustain well-being and meet water demand throughout the year. e.g.canada
• what is water stress?

  this occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use
• what are the reasons for increasing water consumption?

  economic development and rising population
• how is rising population affecting water consumption

  food=increases demand and consumption of water for irrigation of crops and in food processing

  urbanisation=more demand and consumption of water for drinking, cooking and drainage/sanitation
• how is economic development affecting water consumption?

  development= people are wealthier and have a higher standard of living and use more water intensive appliances e.g. dishwashers

  energy=increased demand and consumption of water for non-renewable energy production

  industrialisation= countries produce and manufacture more goods which uses water
• what are the factors affecting water availability?

  climate

  geology

  pollution of supply

  overabstraction

  limited infrastructure

  poverty
• how is climate affecting water availability?

  most places rely on rainfall to feed lakes and rivers for their water supply. hotter climates means more water evaporates from these stores. climate change is altering the amount of rainfall places recieve and causing global temperatures to rise. this means many dry areas are getting drier, increasing the risk of droughts
• how does geoloy affect water availability

  when rain falls on impermeable rock (e.g.clay) it runs off into rivers and lakes. these are easy to get water from. when rain falls on permeable rock (e.g.sandstone) it infiltrates the rock and can form underground water stores (aquifers) which are harder to get water from. however groundwater can make water available in very dry places e.g. sahara desert
• how does over-abstraction affect water availability

  this is when more water from natural sources is used than it is replaced, it is caused by:

  • population growth and economic development
  • improvements in sanitation + hygiene e.g. people shower more frequently
  • high demand from businesses- tourism & recreation can cause water stress during peak holiday seasons
• how does pollution affect water availability?

  water pollution is a major problem in rapidly industrailising countries where industrial waste is dumped into rivers without being treated. animal waste can be hazardous when people share water sources with animals and lack access to sanitation
• how does limited infrastructure affect water availability?

  rapid urbanisation means that more pumps and pipes are needed to ensure safe and reliable access to water. if these arent built fast enough sewage can contaminate the water supply. may also be lack of transport of water to areas of need
• how does poverty affect water availability?

  water providers charge a fee for supplying water to homes. people who are too poor to pay it have to find other sources of water, which may not be safe to drink.
• what are the impacts of water insecurity?

  waterborne disease and water pollution

  food production

  industrial output

  potential for conflict where demand exceeds supply
• explain how water insecurity can cause water borne diseases and pollution

  water thats polluted (e.g by sewage or industrial chemicals) can be more dangerous in areas where water is scarce as people have no alternatives. some waterborne diseases such as cholera can be spread by drinking contaminated water

  queing for water can also reduce economic productivity
• explain how water insecurity can cause reduced food production

  agricultural irrigation uses alot of water, so when theres a water shortage, crop growth can be limited. this can lead to starvation
• explain how water insecurity can cause reduced industrial output


  manufacturing industries are hugely water-intensive, so cant produce as many products during water shortages. this reduces workers' incomes and affects the economy.
• explain how water insecurity can cause conflict

  when countries with water insecurity share the same water sources, such as rivers or aquifers, water shortages can trigger conflicts. one country may try to improve its own water security by taking more water from a river, which can reduce the water security of the countries downstream. e.g. ethiopia built a dam which limited the amount of water other countries got on the river nile
• what are the different strategies to increase water supply

  diverting supplies and increasing storage

  dams and reservoirs

  water transfers

  desalination
• describe dams and reservoirs and how they can increase water supply

  dams are walls built across a river that trap water behind the dam, creating a reservoir

  during times of water surplus the reservoir will be filled, this water can then be released at a steady rate during times of water deficit ensuring there is consistent water supply all year round
• name a dam

  hoover dam in colorado USA
• what are the benefits of dams and reservoirs

  electricity can be generated using the dam, through hydroelectric power

  dams control the river flow, and can reduce the risk of flooding
• what are the disadvantages of dams and reservoirs

  dams are expensive to build and maintain

  reservoirs can cause conflict because they flood agricultural land

  some villiages and towns must be flooded to create the reservoir meaning locals are displaced, habitats might also be destroyed

  reservoirs can lose water from its surface through evaporation, this makes them unsuitable for hot climates

  co2 is released
• describe water transfers and how they increase water supply

  water transfers schemes move water from an area of surplus to an area of deficit

  water is usually moved transferred in canals, pipes and reservoirs
• what are the benefits of water transfers

  supplies large urban cities, where there isnt room to build large reservoirs

  for countries with surplus water supply, water trade can be very profitable

  less risk of water stress in deficit areas
• what are disadvantages of water transfers

  infrastructure can be expensive to build and maintain

  there might be evaporation in canals and reservoirs
• describe diverting supplies and increasing storage and how it can increase water supply

  water supplies can be artifically diverted by building a dam to raise a rivers water level and redirect water to a chosen location, this is usually less disruptive than storing it in a reservoir

  water supplies can also be artifically stored over long periods of time in aquifers underground
• what are the benefits of diverting water supplies and increasing storage

  can store water in areas with little but heavy rainfall

  redues water loss from evaporation

  increases water supply for industry and domestic use
• what are disadvantages of diverting water supplies and increasing storage

  risk of over abstraction

  requires some level of rainfall

  needs permeable rock or soil such as alluvial soil however this is fertile so there may be conflict in use as it can be used for agriculture
• describe desalination and how it can increase water supply

  this involves the removal of salt from seawater so it can be used

  -seawater is either heated until it evaporates , leaving the salt behind, and is condensed as freshwater

  -or seawater is passed through a membrane that removes salt

  this is mainly used by wealthy desert countries
• what are the benefits of desalination

  doesnt rely on rainfall patterns to be consistent

  improves water security for domestic and industrial use
• what are the disadvantages of desalination

  extremely expensive and energy intensive

  involves chemicals e.g. chlorine which reduces water quality

  produces brine as by-product which is very salty and is dumped back into the sea, affecting sea life.
• what is the name of our large scale water transfer scheme

  the central arizona project (CAP)
• describe our large scale water transfer scheme(CAP)


  -the central arizona project is a water transfer scheme wich transfers water from the colorado river to the cities of pheonix and tuscon

  -these cities are located in the sonoran desert which has a severe water deficit
• what are some key facts about our large scale water scheme(CAP)


  aims to protect agricultural prosperity and promote future economic growth

  the canal is 335 miles long

  the scheme cost 4 billion dollars

  supplies phoenix and tuscon in arizona in the sonoran desert