LAS VEGAS (AP) -- A Nevada judge has rejected crucial state approval needed for Las Vegas to draw water from rural valleys straddling the Nevada-Utah state line and pipe it south to slake the thirst of Sin City residents and tourists.
In an order circulated Wednesday, Seventh District Court Senior Judge Robert Estes in Ely directed state Water Engineer Jason King to reconsider his March 2012 approval for the Southern Nevada Water Authority to pump billions of gallons of groundwater a year from sites in White Pine and Lincoln counties.
The judge ordered King, Nevada's top water official, to recalculate the amount of water available in the Spring Valley, Cave, Dry Lake and Delamar valleys; conduct more hydrological studies in two of the valleys; and set standards for limiting water rights conflicts "or unreasonable effects to the environment or public interest."
A representative of one of several environmental and conservation groups in both states opposing the multibillion-dollar Las Vegas water pumping and pipeline plan hailed the ruling as a landmark.
"This basically sets them back to where the Southern Nevada Water Authority has no granted water rights, only applications," said Rob Mrowka, an ecologist with the Center for Biological Diversity.
"Now the SNWA has zero water in hand," Mrowka said.
Water authority spokesman Bronson Mack released a statement noting that parts of the ruling were upheld, including a determination that the water is needed in southern Nevada. He said officials were still examining Estes' 23-page order.
"The court has asked the state engineer to gather additional data before rights are granted and water is developed," the statement said, "and SNWA is confident that this can be done."
King issued a statement saying he was disappointed in the decision but hadn't seen an official copy. He said any further comment would be inappropriate.
A spokeswoman for Nevada Attorney General Catherine Cortez Masto didn't immediately respond to messages about whether the state would appeal.
Estes was blunt in his decision, dated Monday.
"The matter must be remanded to the engineer so that objective standards may be established," he said. "Without standards, any decision is ... arbitrary and capricious."
Officials on all sides said after Estes held two days of hearings on the groundwater question in June that no matter who won, they expected the case would be appealed to the Nevada Supreme Court.
At issue was King's decision to grant the water authority permission to pump up to 84,000 acre-feet of water a year from beneath the four valleys. Water officials in Las Vegas say an acre-foot, or 326,000 gallons, can serve two households per year.
Opponents argued large-scale pumping would ruin fragile ecosystems across state lines and turn the valleys to dust bowls.
The judge faulted the underpinnings of King's findings, including studies by the water authority, and pointed to the more than 20,000-square-mile size of the projected pumping area. A comparable area would cover "great portions" of four New England states and parts of New York, Estes wrote.
He called the plan to siphon water from beneath rangeland and pipe it to Las Vegas "likely the largest interbasin transfer of water in U.S. history."
A push to find more water for Las Vegas has increased in recent years amid ongoing drought in the Southwest and the depletion of the Lake Mead reservoir on the Colorado River to less than half full.
Las Vegas, with about 2 million residents and 40 million visitors a year, draws about 90 percent of its drinking water from reservoir behind Hoover Dam.
Many top Southern Nevada Water Authority officials were talking about drought during meetings Wednesday with federal water managers and representatives from seven other Colorado River basin states.
Mrowka's organization is part of a broad coalition of individuals and conservation groups taking part in the case as the Great Basin Water Network. It also is fighting a right of way granted by the federal Bureau of Land Management for the proposed water pipeline.
Other opponents of the pumping plan include Native American tribes in Nevada and Utah, a Mormon church official and the counties of White Pine, Nev., and Millard and Juab in Utah.
Find Ken Ritter on Twitter: http://twitter.com/krttr