Opponents of the project who live in eastern Nevada and western Utah say the study confirms their worst suspicions about the Southern Nevada Water Authority's plan to tap groundwater in the Snake and Spring valleys near the park and send it to Las Vegas via a 200-mile pipeline.
A Utah water official, though, says it is too early to draw conclusions.
The USGS study, released last week, identified five locations in Great Basin and another five outside the park that are "likely susceptible" to groundwater withdrawals, though it did not attempt to quantify how big a withdrawal would be necessary to trigger problems.
The Southern Nevada Water Authority has proposed taking 25,000 acre-feet per year out of the giant aquifer that straddles the Utah-Nevada state line - which officials say would leave plenty for the region's ecosystem and scattered cattle ranchers who reside and earn their living there.
But those ranchers also have been the most outspoken opponents of the Southern Nevada project, and say the USGS study is simply another piece of evidence backing their argument.
"This is what it's all going to come to sooner or later," Cecil Garland, a Callao rancher, said Friday. "The water is not here. It's a pipe dream and it has been from the very beginning. This is the driest valley in the driest part of the Southwest in the driest part of the United States, and you're going to take that kind of water out? It just defies common sense."
Utah officials, too, have seen the USGS report, and they too were not startled by the results.
But they are not ready to draw any inferences from it. Not yet.
"Nothing in particular came as a surprise. We recognize the interaction between surface water and groundwater," said Boyd Clayton, assistant engineer with the state's Division of Water Rights. "But the report doesn't say 'if you do that, this will happen.' It really just addresses areas where there is the potential of [impacts]. And we think that is a possibility to be concerned about."
Because Nevada and Utah share the aquifer's resources, Utah's approval is necessary for the Southern Nevada Water Authority project to move forward.
Talks are ongoing between Utah and Nevada state water officials over the terms of a possible water-sharing agreement. But Gov. Jon Huntsman Jr. and Utah lawmakers have vowed to protect the state's interests in any deal that is made.
The USGS report, conducted at the behest of the National Park Service, is part of a series of environmental studies being done by both the USGS and Bureau of Land Management. Pat Mulroy, general manager of the Southern Nevada Water Authority, says the new study needs to be put in that context.
"This data collection was done by the [USGS] for the Park Service, and the Park Service is seeking maximum protections," Mulroy told the Las Vegas Review-Journal. "They are obviously going to look at the worst-case interpretation. I can't say I blame them."