Water World

Small-scale management
1. Wells
  1. Dug to reach underground water
  2. Lined with concrete and have a concrete lid to prevent sewage from getting in
2. Hand pumps
  1. More efficient way of reaching groundwater
  2. Less chance of contamination
3. Water barrels
  1. Collect rainwater from gutters
  2. Water can be stored for use in times of drought
  3. The water stays clean in the barrel
Large-scale management
1. The Three Gorges Dam
  1. Negatives
    1. Good farmland was lost
    2. 1.3 million people forced to move
    3. Landslides
    4. Cultural and historical sites lost
    5. Expensive ($2.25 billion)
    6. Downstream areas more susceptible to flooding
    7. Sediment builds up behind dam
    8. Important wetland areas destroyed
  2. Positives
    1. Flood risk along Yangtze reduced
    2. Water can be used for irrigation
    3. Hydroelectric power
    4. Less greenhouse gas emissions
    5. Yangtze is more navigable
2. The Colorado River
  1. Positives
    1. Regulates the flow of water, reducing flood risk
    2. Dams generate electricity
    3. Lakes which form store water for irrigation
    4. Stored water can be used to supply growing cities such as Las Vegas
    5. Year-round supply of clean water for local US cities
  2. Negatives
    1. Land is lost when it floods behind the dams
    2. Sediment builds up which affects HEP generation
      1. Less sediment flowing down the river disrupts local fish habitats
      2. Sandbanks have shrunk so animal habitats are affected
    3. Less water downstream for Mexico
  3. Managed on a large scale
The hydrological cycle
Climate and water supplies
1. Why supplies are unreliable
  1. There may be dry and wet seasons
    1. e.g. the Sahel - has short wet seasons
  2. Weather cycles can cause a number of dry years followed by a number of wet years
  3. Global warming - causes dry areas to become drier and wet areas to become wetter
2. South-west USA
  1. Less water
    1. Less irrigation
      1. Fewer crops
        Causes problems for growing population
Threats to the hydrological cycle
1. River pollution
  1. Untreated sewage pumped into rivers
    1. Management - sewage is treated before being pumped out
  2. Eutrophication
    1. Management - regular fertiliser use
  3. Factory chemicals
    1. Management - factories get remove waste products fro the water before returning it to the river
  4. Plastic bags
    1. Management - recycling centres

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Water World

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	Erstellt von J_McNally vor mehr als 9 Jahre