CARSON CITY -- The state's top water regulator was urged Monday to approve a plan to pump billions of gallons of rural groundwater to Las Vegas by proponents who said Nevada's "destiny" is at stake. But critics said the advocates had failed to make their case.

The pro and con arguments were aired as State Engineer Tracy Taylor heard closing arguments on the Southern Nevada Water Authority's bid to get about 91,000 acre-feet of water yearly from Spring Valley, near the Utah border in White Pine County.

There are 325,851 gallons in an acre-foot, which is almost enough water to supply two Las Vegas homes for one year.

Matt Kenna of the Western Environmental Law Center said his experts showed during two weeks of hearings on the plan that it would likely cause an excessive drawdown of the water table in Spring Valley and lead to "devastating" impacts.

Kenna argued that before any final ruling, the state should update estimates of the amount of water that can be pumped from the valley while leaving enough to protect existing rights and allowing for growth in years to come. While the water authority says about 100,000 acre-feet can be safely pumped each year from the valley, Kenna said other evidence pointed to a safe water yield that could be as low as 70,000 acre-feet.

Water authority attorney Paul Taggart said in his closing arguments that the big question is "whether Nevada is going to control its own destiny" or find itself at the mercy of other states unwilling to share some of their Colorado River water.

Review-Journal reporter Henry Brean contributed to this report.