We are all water users. Streams and rivers that flow from the Wasatch Mountains are important to those of us living along the Wasatch Front. They have supported more than 150 years of economic growth and development and still provide recreational opportunities and scenic beauty.

"Owning" the water that flows in these streams from source to point of use has given our water resource managers the advantage of developing these water resources as they see fit, without depending on delivery from other states. But elsewhere in Utah, some populations rely on water produced out of state. For instance, the Snake Valley of west-central Utah (including farming communities of Eskdale, Garrison, Partoun, Robinson Ranch and Trout Creek of Juab and Millard counties) has 9,530 irrigated acres of farmland and 7,500 acres of streams, lakes and wetlands (based on information in the Utah State Water Plan for the West Desert Basin, 2001).

The valley lies partly in Utah and partly in Nevada, and the present water supply limits the number of acres that can be farmed. About two-thirds of the water supply comes directly from groundwater, much of which reaches Utah from higher elevations in Nevada. This groundwater is very valuable to Nevadans who occupy the driest state in the U.S. (Utah is the second driest).

Plans exist to export water from the Nevada portion of Snake Valley or from the adjacent Spring Valley (which feeds into Snake Valley) to Las Vegas. This would reduce the supply available to Utahns, further reducing farming potential. It would simultaneously promote drying of streams, lakes and wetlands, which would increase dust. Eastward export of dust via prevailing winds would worsen already-poor air quality along the Wasatch Front.

In short, exported water would benefit some Nevadans, reduce local supplies for some Utahns and increase dust along the Wasatch Front.

Throughout history, water users downstream have suffered from water resource depletions upstream. Well-meaning upstream users may have legal right to deplete downstream supplies or, because water management is complicated and difficult, may innocently take more water than they have a right to.

But beware; rights of downstream users are not always top priority for upstream users and not all upstream users are well meaning. Elsewhere, states with downstream water rights have pursued claims to water in the Supreme Court when upstream depletions were excessive, but such victories did not restore water already lost or undo economic and environmental damages already done.

Whether legal or illegal, such damages reduce sustainability and potential for growth. Downstream water users on interstate rivers such as the Colorado River, Rio Grande, Pecos River, Arkansas River and Platte River all face reduced water supply, salty water or no water at all, due in part to upstream uses (water use may also be heavy in downstream states).

Importing water over long distances requires expensive infrastructure and continuous pumping. The expense of pumping rises as fuel prices increase. Like Nevadans, Utahns have looked to distant in-state water supplies to alleviate needs of more populated regions, but these measures remove water from one region to benefit another (there is a "winner" and a "loser"). Thus, substantial economic and political costs are associated with long-distance water export/import.

Effective conservation of local supplies eliminates these costs but requires us to choose more water-wise lifestyles and be supportive of conservation efforts. Nevadans seeking water for Las Vegas must also choose, but their choice is relevant to us because it will affect the resources and environment of Utah. Thus, we must decide whether to support or resist plans for water export from Spring and Snake Valleys.

If plans go forward, Utahns would not be first to suffer damaging depletions from upstream, out-of-state water use. We would simply be repeating history.

Christopher Hoagstrom is an assistant professor in the Department of Zoology at Weber Sate University.