Water World Geography Notes

A summary of notes from the topic Water World. This follows the Edexcel Geography Specification B. Hope it helps :)

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  • Created by: Rebecca
  • Created on: 05-06-11 14:50

The hydrological cycle

  • Input
    • Precipitation: moisture falls from clouds as rain, snow, hail, sleet etc
  • Outputs
    • Evaporation: liquid changes to gas due to sun's energy
    • Transpiration: trees lose water through pores in leaves
    • Rivers: flow of water usually downhill to an ocean
  • Transfers
    • Infiltration: water moves from the surface into the soil beneath
    • Run-off: water flows overland
    • Through-flow: water flows through soil to a river or sea
    • Groundwater flow: water flows horizontally through soil and rock
    • Percolation: movement of water from soil to rocks beneath
  • Stores
    • Groundwater: water is stored underground in rocks after percolation
    • Surface storage: water stored on Earth's surface - lakes, puddles etc.
    • Interception: leaves on trees capture precipitation
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Global stores of water

  • Oceans - 97%
  • Glaciers - 2%
  • Groundwater - 0.7%
  • Lakes - 0.1%
  • Soil - 0.005%
  • Rivers - 0.0001%
  • Living organisms - 0.0004%


  • Oceans can't be used as they're salt water - which causes dehydration
  • Glaciers are frown so would need energy to heat them
  • There's is very little from lakes and rivers
  • Water found in soil is contaminated by siltation
  • Living organisms can't have water extracted from them!

Most water is abstracted from groundwater as infiltration makes it clean and there's less litter/pollution. Large amount of water infiltrates and it can't evaporate.

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Why is water use increasing?

  • Population is increasing: need more water for hygiene, washing etc.
  • Used more in irrigating crops to feed growing population
  • Used more in growing industry e.g. steel and paper
  • Urbanisation means by 2025 60% will live in urban areas and water and sanitation infrastructure won't be able to cope
  • Tourism e.g. swimming pools and golf courses use lots of water
  • Used for HEP to provide energy
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Unreliable and insufficient water supply in The Sa

  • Facts
    • Arid land in sub-Saharan Africa, near equator so high temperatures
    • Very little rainfall (250mm-450mm per year)
    • Precipitation mainly in 1-2mths so very little for the rest of the year
    • Mainly LEDCs - growing pop. so increasing demand for water
    • Since 1970 the water supply has been below average
  • Problems
    • Rain falls as torrential downpours so causes flooding
    • Grasses die, soil becomes impermeable as it dries and cracks, this means water can't infiltrate so it's lost as run-off (desertification)
    • Crops can't survive with such little water - reduced yield - starvation
    • Subsistence farmers can't grow enough to feed family
    • Livestock increase by 40% in rainy season causing overgrazing and the land can't support such numbers in dry season
    • Drought causes seasonal rivers and water holes to dry up
    • The water table falls as groundwater is used
    • Both physical and economic water scarcity: limited supply and people are very poor so can't afford it
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Impact of Climate Change: The Sahel

  • Higher temperatures cause even more irregular weather conditions
  • Even less precipitation
  • More evaporation so rivers and surface storage dry up
  • Rising sea levels may contaminate groundwater with salt water
  • As land becomes more arid, sand and dust storms may cause more damage to humans and property
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Good - I loveee the colours!! :D



Thank you :)



Very easy to read - thank you for this!


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