U.S.: ‘Zero’ chance of Colorado River water shortage in 2018

Heavy winter snows in the Rocky Mountains have rescued the thirsty Western U.S. for another year.

U.S. water managers said Tuesday there will be no water cutbacks in 2018 for millions of residents and farmers served by the Lake Mead reservoir on the Colorado River that lies behind the Hoover Dam.

"The projection indicates there is no chance of shortage in 2018," said Rose Davis, spokeswoman for the U.S. Bureau of Reclamation. "Zero."

January water levels are expected to be 8 feet (2.5 meters) above the point that triggers a drought-shortage declaration on the closely watched lake, according to a key 24-month projection by the water system management agency.

The report is a turnabout from a year ago, when the agency projected a 50-50 chance the lake level would fall just below the shortage point of 1,075 feet (330 meters) above sea level.

Under the interstate agreements governing the river's use, a shortage declaration would force officials to cut some water deliveries to Arizona and Nevada.

Overall, the river serves more than 40 million people in cities, farms and tribes in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming. Mexico also gets a share.

Davis said conservation and water-banking programs involving Mexico, California, Arizona and Nevada were a main reason the largest constructed reservoir in the U.S. will not fall below the drought shortage point.

Water banking allows users to leave some of their water in Lake Mead for later use, with some restrictions.

Combined, conservation and water banking have added about 10 feet (3 meters) to the lake level.

Snowmelt from heavy snowfall from mountains in Colorado, Utah and Wyoming also boosted the lake's water level.

"We had a good water year — 113 percent of average," Davis told The Associated Press. "That raised our capacity in the whole system from 51 to 57 percent."

The report projects a 31 percent chance of a shortage declaration in January 2019.

A 1922 interstate agreement allocates a combined 15 million acre-feet of water to the states and Mexico. An acre-foot is about 326,000 U.S. gallons (1.2 million liters), enough to serve two typical homes for a year in the U.S. West.

More than 16 years of drought have taken a visible toll on Lake Mead, which is currently at 38 percent of capacity while downstream farmers withdraw water to irrigate summer crops. A white mineral "bathtub ring" left behind when the water was higher is visible on rocky shorelines.

But Lake Powell, another huge reservoir on the Colorado River upstream from Mead, has improved to 63 percent capacity.

That will provide options for water managers who control the water flow from Lake Powell, east of the Grand Canyon, to Lake Mead, west of the national park. Officials have compared the process to pouring water from one teacup to another.

A drought shortage declaration would cut 11.4 percent of Arizona's promised 2.8 million acre-feet (3.4 trillion liter) allocation, and 4.3 percent of Nevada's allotted 300,000 acre-feet (370 billion liters). The amount of water at stake combined would serve more than 625,000 homes.

Central Arizona Project officials say cuts in water deliveries would affect Arizona farmers before cities. The project serves a heavily populated region that includes the state's largest cities, Phoenix, Tucson and Mesa.

Las Vegas, which draws 90 percent of its water from Lake Mead, might not feel much effect from a shortage declaration because conservation and reuse programs have cut the city's consumption by about 25 percent in recent years, Southern Nevada Water Authority officials say.

Even if a shortage is declared, drought-stricken California will be able to draw its full 4.4 million acre-foot allocation of Colorado River water.

Elliott reported from Denver.