There’s a 50-50 chance that the Arizona- and Nevada-bordering, human-made Lake Mead will become Dry Ditch Mead by 2021, according to a study to be published in the journal Water Resources Research. Oh, and that’s a conservative estimate, say the study authors, as is this one: By 2017, there’s an equally good chance that water levels in the reservoir could drop so low that the Hoover Dam would be incapable of producing hydroelectric power. Lake Mead provides water to thirsty cities including Los Angeles and Las Vegas, as well as H2O to agricultural areas. Coauthor Tim Barnett says he was “stunned at the magnitude of the problem and how fast it was coming at us,” and the study recommends that officials implement conservation and mitigation policies and technologies. Stat.