A persistent drought in the American Southwest forced the Anasazi to abandon their settlements 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.
I wrote the above paragraph in 2015. Six years later, Lake Mead has even less water.
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.
Today CNN reported that Lake Mead "registered its lowest level on record since the reservoir was filled in the 1930s." It's at 36 percent capacity, "a number that will continue to fall as the reservoir's rapid decline continues to outpace projections from just a few months earlier. Water levels are projected to drop another 20 feet by 2022."
Accuweather says low rainfall this year isn't helping:
The last measurable precipitation in the area of Lake Mead was on May 16, according to AccuWeather Senior Meteorologist Carl Erickson. However, that only amounted to 0.01 of an inch of rainfall. The last notable amount of rainfall goes back a few months.
"You have to go back to March 11 and March 12 when a little over a half of an inch of rain fell, 0.63 inches, over the course of those two days," Erickson said. "Total rainfall year to date, Jan. 1 to June 15, was 0.85 of an inch. Normal for that same time period is 2.04 inches." That the meager amount is only 42% of normal rainfall for the year so far.
Looking ahead, Erickson added, it's likely the area will remain dry through the rest of June and into early July. To date, there's been no measurable rainfall in June.