Negative Impact of Dams
- In flat basins large dams cause flooding of large tracts of land, destroying local animals and habitats.
- People have to be displaced causing change in life style and customs, even causing emotional scarring. About 40 to 80 million people have been displaced physically by dams worldwide.
- Large amounts of plant life are submerged and decay anaerobically (in the absence of oxygen) generating greenhouse gases like methane. It is estimated that a hydroelectric power plant produces 3.5 times the amount of greenhouse gases as a thermal power plant burning fossil fuels.
- The migratory pattern of river animals like salmon and trout are affected.
- Dams restrict sediments that are responsible for the fertile lands downstream. Farmers use chemical fertilizers and pesticides to compensate for the loss in productivity.
- Salt water intrusion into the deltas means that the saline water cannot be used for irrigation.
- Large dams are breeding grounds for mosquitoes and cause the spread of disease.
- Farmers downstream who used to wait for the flooding of the fields to plant their seeds are affected.
- Dams serve as a heat sink, and the water is hotter than the normal river water. This warm water when released into the river downstream can affect animal life.
- Peak power operations can change the water level thirty to forty feet in one day and can kill the animals staying at the shorelines.
- Around 400,000 km2 of land worldwide has been submerged due to the construction of dams.
Nov 13th, 2014
Oct 24th, 2016
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