Saturday, July 8, 2006 | 7:42 a.m.
The Southern Nevada Water Authority has authorized spending $750,000 on two consultants who are to examine various ways of augmenting the drought-starved Colorado River - including the 60-year-old practice of cloud seeding.
But according to a story in the Las Vegas Sun on Thursday, "seeding" clouds likely could produce only a limited supplement to the Colorado River system that supplies the Las Vegas Valley's drinking water.
The method involves introducing tiny particles of silver iodide into clouds, where ice forms around the particles. As these ice "seeds" grow, they fall to the Earth as rain or snow, the Sun reports. The silver iodide is added to clouds from aircraft and from rockets fired from the ground or mountaintops.
Some experts told the Sun that while some rain may fall, seeding is not an exact science. An official from the federal Bureau of Reclamation, which controls the lower half of the Colorado River and Lake Mead and Lake Powell reservoirs, told the Sun that "scientific work so far has not been able to measure" that rain from seeding effectively increases the water supply. And the government needs more of a sure thing - the Colorado River and its reservoirs are barely 60 percent full.
However, the experts and the studies don't always agree. For example, the Sun reports, research released by the Upper Colorado River Commission shows that seeding in the Rocky Mountains could provide five times the amount of water used in Las Vegas.
And a scientist involved in an ongoing, $8.8 million study in Wyoming by Nevada's Desert Research Institute told the Sun that preliminary results are "quite promising" and could exhibit a 10 to 15 percent increase in rain and snowfall.
Still, we don't know enough. While it is important to investigate ways in which we could increase the amount of rain that falls during a drought, modifying the weather should be viewed as a periodic supplement in a more comprehensive approach that emphasizes conservation and effectively using the water that is available naturally. Technology cannot replace good judgment.
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