A new study by the U.S. Geological Survey makes it sound as if Utah's western deserts have plenty of extra water. That comes as a surprise to the few ranchers there who are trying to cope with dried-up springs and meager streams.

But it also paints a vivid picture of how interconnected water supplies are in the arid deserts of the West, which ought to be enough to put an end to any talk of pumping some of that water to meet the needs of Las Vegas.

Large desert metropolises need water, of course. But this isn't the way to meet those needs. The results could be damaging and irreversible.

The report, sent to Congress and released publicly over the weekend, concludes there is plenty of annual runoff to meet the needs of a Las Vegas project, which wants to pump 25,000 acre feet of water from an underground aquifer in Snake Valley, an area that includes parts of both Nevada and Utah.

The report also concludes that some of the rain in mountains of Nevada ends up flowing underground to parts of the Great Salt Lake Desert, which sheds new concerns about a separate plan to pump water for Las Vegas from Spring Valley in Nevada.

A map in the report, complete with arrows, shows how groundwater flows from one region to another throughout the area. Generally speaking, this ancient natural system provides a remarkable means to sustain life in an otherwise harsh environment.

There may indeed be enough water there to supply what Las Vegas wants, but, if nothing else, the report demonstrates how fragile and interconnected water is in this region. That should end any thought of disrupting it.

The folks who ranch in Utah's sparsely populated western desert have a number of credible worries. The first is that they scarcely have enough for the grazing and growing they need to do as it is. They also worry about the future of greasewood trees, which are an important part of the desert's ecology.

These trees have deep roots that tap into underground aquifers. Anything that lowers those aquifers might kill those trees. In addition, they worry that polluted aquifers below the salt desert are being held in check by the pressure of freshwater aquifers. A pumping project could reduce that pressure and lead to pollution of freshwater supplies.

That would be an ecological disaster that could make living and ranching in western Utah impossible. The public has until Aug. 1 to comment on this report. Our recommendation is to tell Las Vegas to look elsewhere for its water.