It's better for Utah to sign two contracts with Nevada to manage ground water beneath Snake Valley than to ask the U.S. Supreme Court to apportion the water. That's the opinion of three Utah water attorneys who have analyzed the agreements. But that's not the whole story.
It is environmental folly for Las Vegas to pump ground water from beneath the arid valleys to its north and send it down a 275-mile pipeline to Sin City. Unfortunately, Utah has little leverage over what happens to the water beneath those valleys that lie entirely within Nevada. However, Snake Valley straddles the Utah/Nevada state line, so both states lay claim to the ground water beneath it.
Negotiators for the two states reached agreements in 2009 to apportion half of those waters to each state and provide a process to monitor their withdrawal in a series of incremental steps. The idea is to protect the water rights of both states, to provide monitoring of withdrawals, and to require mitigation, including an end to pumping, if that becomes necessary to prevent irreversible harm to existing users and the environment.