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3. Dams to
provide hydroelectric power and store water for irrigation have had immensely beneficial
consequences for many millions of people in Egypt, Ghana, Brazil and other countries. But
the dams bring surface water to previously arid tropic zones; so malaria-carrying
mosquitoes and water snails, the intermediate hosts of schistosomiasis, flourish. Two of
the world's worst tropical diseases invade new territory. The ecological and human cost of
large hydro-electric dams can be considerable.
Sometimes previously sustainable agricultural ecosystems are disrupted and large
numbers of people are forced to move because their habitat is submerged. At other times a
hunter-gatherer culture is damaged or destroyed, as in the Amazon rain forest and in
Northern Quebec. There is always a price to pay, and this must be traded off against the
benefits. |