water

• Ground water: Water that is stored in the soil and is available for use.
• Surface water: Water that is close to the surface of the earth, such as lakes, rivers, and streams.
• Dams/reservoirs:

  • Dams and reservoirs serve a number of different functions but one of the largest is to maintain an area's water supply.
  • Another major use of dams is power generation as hydroelectric power is one of the world's major sources of electricity.
  • The creation of a reservoir requires the flooding of large areas of land, at the expense of the natural environment.
• Surface water:

  • Some freshwater is stored on the land surface. Surface water includes the streams, lakes, reservoirs (man-made lakes), and freshwater wetlands.
  • The amount of water in our rivers and lakes is always changing due to inflows and outflows.
  • Inflows to these water bodies will be from precipitation, overland runoff, groundwater flow or tributaries joining.
  • Outflows from lakes and rivers include evaporation and discharge to groundwater.
• Wells:

  • The traditional method of obtaining groundwater in rural areas.
  • Hand-dug wells can range in depth from about 5m deep, to deep wells over 20m deep
  • Wells with depths of over 30m are sometimes constructed to exploit a known aquifer.
• Advantages of hand-dug wells:

  • Cheap materials can be used.
  • Can be constructed by local artisans so communities can build themselves.
  • Generally good yields.
• Disadvantages of hand-dug wells:

  • Can be time-consuming to construct.
  • Risk of collapse if not supported properly.
  • Depth of well is limited.
  • Can be open to contamination unless capped or protected.
• Boreholes: A vertical hole drilled into the ground to obtain water or other substances.
• Advantages of boreholes: Cheap and easy to drill, can be drilled into hard rock
• Physical water scarcity: When water is not available for human use.
• Economic water scarcity: When water is scarce for economic purposes, such as agriculture, industry, and domestic use.
• MEDCs:

  • Build more reservoirs.
  • Develop a water grid which would allow transfer of water.
  • Raise the cost of water.
  • Impose drought orders eg. hose-pipe bans.
  • Save water e.g. take showers rather than baths.
• LEDCs:

  • Build low walls across fields to reduce run off.
  • Plant trees to conserve moisure.
  • Use micro-dams to store water for irrigation.
  • Plant drought resistant crops.
• Methods to reduce water shortages:

  • Dam/reservoir building
  • Desalination plonts
  • More boreholes/wells underground.
  • Cloud seeding.
  • Water treatment/purification.
• CS: Water Shortage; Catinga, Brazil:

  • Loss of lives/higher death rates; due to dehydration.
  • Less food production/crops die; so people die of starvation/malnutrition.
  • Migration to urban areas such as Rio de Janeiro; as crops fail in rural areas.
  • Slums grow in city.
  • Puts off tourists.
  • Rationing/water restrictions etc.