Las Vegas has won approval of the Nevada state engineer to siphon huge amounts of groundwater from beneath valleys to the north and pipe it to Sin City. This is bad news for Utah. It would almost certainly damage the fragile Great Basin ecosystem, its complex groundwater network and water rights in the Beehive State.
On paper, the pumping scheme looks reasonable. It would only proceed after hydrologic and biological studies. The full amounts of water the state engineer has granted could not all be taken at once. Rather, there would be initial withdrawals, followed by monitoring to see how the aquifers and biology were affected. If, after eight years, the effects were not seriously bad, more water could be pumped. There would be more monitoring.
The trouble with this approach is that, unlike surface water in a river, the effects of underground pumping often are not immediately seen. Plants could die off only slowly. Once the damage is apparent, however, it may be irreversible, and the political pressure to keep pumping water south, particularly after Las Vegas had invested billions in the pipeline project, would be enormous. The complaints of a few ranchers in Nevada and the people of Utah would not count for much.