Monday, June 16, 2008

Good and Bad of Hydroelectric Power

Good points to note:

  • Do not emit harmful asmospheric pollutant E.g. carbon dioxide
  • Does not contribute to global warming/ acid rain
  • Do not result in the risks of radioactive comtamination
  • Regulate seasonal variation in water which prevents flooding
  • Bom to local economy because these places would be good location for water sports and fishing (tourism)
  • Water can still be used for irrigation and drinking even when after it travels through a dam

Bad points:

  • Flood large areas of land that may be forested causing deaths of thousands of organisms
  • Vegetation previously covering these lands would rot and give off carbon dioxide and other greenhouse gases
  • These gases are equivalent to those from other sources of electricity
  • Damming a river change the amount and the quality of water downstream, preventing fish from migrating upstream to spawn
  • Silt would be trapped in a dam and deposit on the bed of the reservoir altering the quantity of water and affecting electrical generation
  • River downstream deprived of silt and river flood plain would not be fertilize, causing farmers to turn to man-made fertilisers which would pollute that water and land
  • Bacteria would be formed when vegetation decay and pses a health hazard to people who feed on the aquatic animals (bioaccumulation)
  • Dependent on the climate to stay constant, therefore when the amount of water in reservoirs decreases, the dams would not function properly
  • Forced resettling for people who are displaced by flooding
  • Loss of land used to grow food
  • Low oxygen level and slightly acidic conditions promote growth of bacteris that releases metals such as mercury which fish absorbs
  • Alter the quality of water, e.g. increased or decreased dissolved oxygen, increases in total dissolved gases, modified nutrient levels, thermal modification andheavy metal levels.

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