DENVER (AP) -- U.S. officials say the chances of a shortage in the vital Colorado River system have risen to 57 percent in 2020.
A U.S. government report released Friday says the odds of a shortfall rose from 52 percent in May. Officials say less water flowed downstream this summer than expected.
The report estimates the amount of water that will be in Lake Mead, the river's biggest reservoir.
If the reservoir surface drops below 1,075 feet (330 meters) above sea level, some deliveries would be cut under agreements governing the system.
Arizona, Nevada and Mexico would have their shares reduced first in a shortage.
The river serves 40 million people and 6,300 square miles (16,300 square kilometers) of farmland in Arizona, California, Colorado, Nevada, New Mexico, Wyoming and Utah and Mexico.