DAM-BUILDERS: be careful when you create a reservoir because bigger storms and flooding could be on the way. That's the warning from an analysis of more than 600 dams, many of which have brought more extreme rainfall.
The idea that large bodies of water might influence rainfall is not new. But until now, no one had studied the effect of large dams and their reservoirs.
Faisal Hossain of Tennessee Technological University in Cookeville and colleagues looked at the magnitude of the biggest storms near 633 of the world's largest dams before and after construction. They found that in many places the level of precipitation in the most extreme rainfall events grew by an average of 4 per cent per year after a dam was built, with the relationship especially strong in semi-arid regions. There was also an increase in the frequency of rainy days (Natural Hazards ...
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