A persistent drought in the American Southwest forced the Anasazi to abandon their towns a thousand years ago. Eventually, the precipitation returned. Hoover Dam in Nevada was built in 1931, "during an especially wet period for the West." But today Lake Mead, which powers Hoover Dam's generators, is at an all-time low after a drought of 22 years with no end in sight.
Lake Mead in Nevada is the world's largest man-made reservoir and provides water to 25 million people. The conditions are so bad that one of the reservoir's water intake valves has been exposed for the first time. Nevada is now using a low lake pumping station to deliver water to homes and businesses.
In 2009 I wrote an article for Good about the crisis:
Lake Mead stores water from the Colorado River. When full, it holds 9.3 trillion gallons, an amount equal to the water that flows through the Colorado River in two years. The water from Lake Mead is used for many things. It irrigates a million acres of crops in the United States and Mexico, and supplies water to tens of millions of people. Its mighty Hoover Dam generates enough electricity to power a half-million homes. Additionally, the power from Hoover Dam is used to carry water up and across the Sierra Nevada Mountains on its way to Southern California.In 2000, the water level at Lake Mead was 1,214 feet, close to its all-time high. It's been dropping ever since. When Lake Mead was built during the 1920s and 1930s, the western United States was enjoying one of the wettest periods of the past 1,200 years. Even today, our so-called drought is still wetter than the average precipitation for the area averaged over centuries. In other words, for the last 75 years, we've been partying like it's 1929. Farmers grow rice by flooding arid farmland with water from Lake Mead; residents of desert communities maintain front lawns of green grass; golfers demand courses in areas where the temperature exceeds 100 degrees Fahrenheit during the summer.