But the chronic drought that has affected the western United States for years has reduced the volume of the reservoir so much that the hydroelectric plant may soon no longer be operational.
“We are in the 23rd year of drought here in the Colorado River Basin, and Lake Mead has fallen to 28%” of its capacity, explains Patti Aaron, of the Bureau of Reclamationthe federal body that manages the dam., “There is no longer as much pressure to push the water through the turbines, so the efficiency drops and we are not able to produce as much energy”, she continues.
Launched in 1931, in the midst of the economic crisis, the work of the Hoover Dam had mobilized thousands of workers to erect what was then the largest hydroelectric dam in the world.
The work bars the Colorado River, giving rise to Lake Mead, which remains to this day the largest reservoir in the United States. At its highest, the lake reached an altitude of 365 meters above sea level. But after more than twenty years of drought, it is now at 320 meters, its lowest level since filling.
The lake is currently losing about a foot every week. If it drops below 289 meters, the dam gates will no longer be submerged and the turbines will stop.
Melt of ice
The Colorado River originates in the Rocky Mountains and meanders for more than 2,300 km through Colorado, Utah, Arizona, Nevada, California and then northern Mexico where it empties into the sea.
It is mainly fed by snowfall which accumulates during the winter at high altitudes, before gradually melting during the warmer months. But under the effect of climate change, precipitation is decreasing and the snow is melting faster, depriving the river of some of its resources, which supplies water to tens of millions of people and many farms.
” Out of sight out of mind “
For Stephanie McAfee, a climatologist at the University of Nevada in Reno, the American West has always had this improbable side. “The average rainfall in Las Vegas is about ten centimeters a year,” she says.
“For large cities like Las Vegas, Phoenix or Los Angeles to exist, we use the water that falls in the form of snow in western regions that are much wetter” and remote, adds the scientist.