After back-to-back driest years in a century on the Colorado River, federal water managers are giving Arizona and Nevada a 50-50 chance of having their water deliveries cut in 2016.
A U.S. Bureau of Reclamation operations plan being made public Friday will slow the flow of water from the Lake Powell reservoir upstream of the Grand Canyon to the huge Lake Mead reservoir that provides Las Vegas drinking water.
But a bureau official says Lake Mead won't reach a low point next year that would trigger cuts to Sin City's main drinking water supply.
The bureau says cities, states, farmers and Indian tribes downstream will get their full water deliveries next year - and probably in 2015.
Seven U.S. states, several tribes and Mexico share water from the river.