A group of investors is floating a plan to dam the Green River and let other Western states borrow the water before it flows out of Wyoming.

But the idea could be dead in the water already, considering the legal and environmental challenges it would face.New Water Inc. has requested water rights to build a 202,000-acre-feet reservoir a few miles north of Green River. The dam would flood about seven square miles. The stored water would be leased to Nevada or other states in the Colorado River Basin.

"We are a headwater state," said Coyne "Sonny" Tibbetts, president of New Water Inc. "Once it gets away from us, it's gone."

The Colorado River Compact gives the Upper Basin states, including Wyoming, 7.5 million acre-feet of the river's annual flow. The lower states, Nevada, California and Arizona, share the remaining 7.5 million acre-feet.

Wyoming uses only about half of the 1.2 million acre-feet of the water allocated from the Colorado River. Under a leasing agreement, Wyoming could get the water back if it needed the water more than the state leasing it, Tibbetts said. If the water is sold, it could not be returned.

"Maybe that's far-fetched and hard to understand, but we felt it would help the state," he said.

The idea of "water marketing" has been discussed by Western states, but currently the Colorado Compact does not allow water to be sold or leased.

"You never know when conditions may change," said John Barnes, head of the Surface Water and Engineering Division. "We don't expect them to, but they are taking a gamble that they may change."

The compact would have to be renegotiated and all seven states in the compact would have to approve any water marketing proposal, said David Donnelly, deputy general manager of the Southern Nevada Water Authority.

Despite legal questions about leasing the water, Wyoming officials will continue to evaluate the technical aspects of the project, Barnes said.