Built in 1350 in what is now Iran, the 63-metre-high Kurit Dam was long regarded as the world’s highest dam. In the 20th century, technology then became sufficiently advanced to allow the construction of dams that were much bigger in size.
Nowadays, dam construction is no longer bound by technical constraints, as the Itaipu Reservoir in Brazil, the Three Gorges Dam in China and the 300-metre-high Nurek Dam barrage in Tajikistan convincingly testify.
Also the number of dams is steadily increasing. Around the turn of the millennium, there were already more than 45,000 large barrages around the world. Hundreds of dams of 60 metres or more in height are currently under construction.
But this rapid development at the service of electricity generation and irrigation also reveals the downside of progress: huge dam structures always have an enormous impact on the ecosystem and on traditional human settlements.
It is estimated that between 40 and 80 million people have meanwhile been forced to leave their homelands to make room for dams. As many as 500 million people inhabit the areas downstream of large dams and are therefore immediately threatened by potential dam bursts.
All these effects and hazards were hardly taken into consideration in the planning and execution of hydropower and irrigation projects in the past.
(Source: aqua press Int. 4/2010, Ludwig W. Fliesser)
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