LAS VEGAS >> A federal judge tapped the brakes today but didn’t stop a proposal for a massive and expensive water pipeline to draw underground water from rural valleys along Nevada’s eastern edge to supply the growing Las Vegas metropolitan area.

The federal Bureau of Land Management needs to take another look at possible environmental effects of the Southern Nevada Water Authority project and identify what can be done about them, U.S. District Judge Andrew Gordon said.

The judge characterized the fixes he ordered as “narrow deficiencies” in environmental impact statements.

They include whether the project will meet Clean Water Act requirements and whether it will be possible to replace or restore remote wetlands if groundwater pumping begins in the Spring, Cave, Dry Lake and Delamar valleys.

Pipeline opponents say ancient natural water basins beneath the Nevada-Utah state line aren’t naturally replenished in today’s arid climate conditions.

“There can be no question that drawing this much water from these desert aquifers will harm the ecosystem and impact cultural sites,” the judge said. “On the other hand, southern Nevada faces an intractable water shortage.”

Both sides interpreted Gordon’s 39-page ruling as favorable.

Center for Biological Diversity attorney Marc Fink called it “a win for wildlife and fragile habitat across eastern Nevada.”

“There are serious questions about whether (the federal Bureau of Land Management) can mitigate the severe impacts of this enormous water grab, which would destroy thousands of acres of wetlands and important habitat for many sensitive wildlife species,” Fink said.

Southern Nevada Water Authority officials, however, pointed to Gordon’s finding on what the judge called environmentalists’ primary complaint: That the federal Bureau of Land Management agreed to wait until water starts flowing before identifying effects and requiring mitigation.

“The U.S. District Court ruled that the BLM appropriately phased the (environmental) analysis and evaluated cumulative environmental and climate change impacts, and considered cultural resources and tribal water rights,” authority spokesman Bronson Mack said in an email statement.

He said the water authority was confident federal land managers would properly address the judge’s issues.

Simeon Herskovits, representing the Great Basin Water Network, Indian tribes and Nevada’s White Pine County, predicted it won’t be easy to correct the deficiencies because during decades of study the water authority hadn’t provided any “concrete verifiable plan.”

Herskovits pointed also to a crucial week of hearings beginning Sept. 25 before Nevada’s top water official, State Engineer Jason King, on a state judge’s order that he reconsider his March 2012 finding that there is enough underground water to supply the pipeline.

Gordon’s decision came less than a month after he held a first-ever federal court hearing on the long-discussed pipeline project.

All parties expect the case will be appealed to the 9th U.S. Circuit Court of Appeals in San Francisco.

The judge acknowledged the complexity and expense of a project to deliver enough water to serve more than 165,000 homes a year across a distance comparable to a drive from Los Angeles to Las Vegas.

The water agency concedes the pipeline will cost billions of dollars to build, but insists it will become essential if drought keeps shrinking the Lake Mead reservoir on the Colorado River, which supplies 90 percent of Las Vegas drinking water.