Water managers say there's a better-than-even possibility that Mexico and the U.S. states of Arizona and Nevada will get less water from the Colorado River in 2020 because of a drought.
U.S. officials said Wednesday there's a 52 percent chance the river's biggest reservoir, Lake Mead, will fall low enough in 2020 to trigger cutbacks under the agreements governing the river.
The reservoir has never fallen low enough to trigger cutbacks before.
The Colorado serves 40 million people in seven Southwestern U.S. states and Mexico. Researchers say a 19-year drought, growing demand and climate change have overtaxed the waterway.
Federal forecasters said Monday the river is expected to carry only 43 percent of the average amount of water this year into Lake Powell, another big reservoir upstream from Lake Mead.