Retreating waters at Lake Mead expose the end of the boat ramp at Temple Bar, Ariz., in this Aug. 16 photo. Another year of below-average snowfall in the Rocky Mountains will mean less water for the Colorado River and further declines at Lake Mead. Photo by Ruben D. Luevano/Review-Journal

Just in time for a state hearing next week that could decide where Southern Nevada gets its water in the future, federal officials have announced the results of another dreary season on the Colorado River.

From April to July, when the river receives most of its snowmelt from the Rocky Mountains, the flow of water into Lake Powell was only 67 percent of average.

According to the National Weather Service's Colorado Basin River Forecast Center in Salt Lake City, about 5.3 million acre-feet of water flowed into the reservoir on the Utah-Arizona border during the traditional snowmelt season this year. That's roughly 3 million acre-feet less than Lake Powell is scheduled to release in the coming year to meet water orders in Southern Nevada and elsewhere downstream.

"It's yet another dry year in a string of dry years," said Tom Pagano, water supply forecaster for the U.S. Department of Agriculture. "It's pretty rough."

There are about 326,000 gallons in an acre-foot, which is almost enough water to supply two Las Vegas homes for one year.

The Las Vegas Valley gets about 90 percent of its water supply from the Colorado River.

The below-average inflow only will worsen the situation at Lake Powell, which has shrunk to 49 percent of capacity amid seven years of drought.

It also will hurt Lake Mead, which is barely half full itself but won't be allowed to recover until Powell refills significantly.

"That's scary," said Pat Mulroy, general manager of the Southern Nevada Water Authority. "And we walked into this snow year feeling ecstatic because we were at almost 100 percent of normal."

On Monday, State Engineer Tracy Taylor will convene a three-week hearing on the water authority's plan to pipe groundwater to the Las Vegas Valley from White Pine County. Mulroy said the water is needed to meet demand created by growth and reduce the community's dependence on the Colorado.

Pagano said the river's reversal of fortune came at record speed.

As recently as April, federal forecasters were predicting an almost normal water year on the Colorado, but an abnormally hot and dry spring erased all that.

"It was the most rapid decline in the forecast after April 1 in the history of this agency," Pagano said. "It was a pretty serious right turn."