| Born in the Rocky Mountains, the Colorado river flows on 1430 miles, into the gulf of California, after having crossed the most arid areas of North America. A century ago, the Americans started to control its waterflow. Many dams strew its course.One of the most important, the Glen Canyon dam was completed in 1963. Seventeen years were necessary to fill up lake Powell behind the high concrete wall. But since the 1990's, following several consecutive years of drought, water level has dropped more than 132 feet, as the white mineral deposit marks left by water on the red sandstones cliffs show. Each year, 2,5 % of the volume of this invaluable freshwater tank are lost by the simple play of evaporation. However, the hydroelectric turbines are always supplied by waters of the lake which slowly goes up since 2005. The promises of dams are not always held, especially if the effects of climate change increase in scale. |
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