Because of the megadrought that’s gripping the southwestern United States, the federal government is cutting back how much water it delivers to California, Arizona and Nevada by a lot, about as much as Las Vegas uses in a year. It’s something water managers never thought they’d have to do. Alex Hager reports on the Colorado River from member station KUNC in Greeley, Colo., and joins us now to explain what’s going on. So decades ago, the U.S. built huge dams on the Colorado River specifically to store water as insurance against droughts. Why isn’t that system working now?