U.S. officials on Monday declared the first-ever water shortage from a river that serves 40 million people in the West, triggering cuts to some Arizona farmers next year amid a gripping drought.
Water levels at the largest reservoir on the Colorado River — Lake Mead — have fallen to record lows. Along its perimeter, a white “bathtub ring” of minerals outlines where the high water line once stood, underscoring the acute water challenges for a region facing a growing population and a drought that is being worsened by hotter, drier weather brought on by climate change. States, cities, farmers, and others have diversified their water sources over the years, helping soften the blow of the upcoming cuts. Federal officials said Monday’s declaration makes clear that conditions have intensified faster than scientists predicted in 2019 when Arizona, Nevada, California, and Mexico agreed to give up shares of their water to maintain levels at Lake Mead. The voluntary measures weren’t enough to prevent the shortage declaration.
Formed by building Hoover Dam in the 1930s, Lake Mead is one of several man-made reservoirs that store water from the Colorado River, which supplies household water, irrigation for farms, and hydropower to Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming and parts of Mexico.
"This used to be the bottom of the lake," @JoshNBCNews reporting on water shortages in the nation's largest reservoir. "If you look and see this white ring over there, they call it the bathtub ring, that's where the water level used to be years ago in Lake Mead." pic.twitter.com/8cNockXHrH
— MSNBC (@MSNBC) August 16, 2021
But water levels at Lake Mead and Lake Powell, the river’s two largest reservoirs, have been falling for years and faster than experts predicted. Scorching temperatures and less melting snow in the spring have reduced the amount of water flowing from the Rocky Mountains, where the river originates before it snakes 1,450 miles southwest and into the Gulf of California.
Arizona will be the hardest hit and lose 18% of its share from the river next year, or 512,000 acre-feet of water. That’s around 8% of the state’s total water use. An acre-foot is enough water to supply one to two households a year. Nevada will lose about 7% of its allocation, or 21,000 acre-feet of water. But it will not feel the shortage because of conservation efforts and alternative sources of water. California is spared from immediate cuts because it has more senior water rights than Arizona and Nevada. Mexico will see a reduction of roughly 5%, or 80,000 acre-feet.
Today, @usbr released its 2022 operating conditions for Lake Powell and Lake Mead.
— US Department of the Interior (@Interior) August 16, 2021