CARSON CITY -- Gov. Jim Gibbons' dream is to sell state-owned water rights and use the money to build highways, but the idea might only raise enough money for a few offramps.

In a interview last week, Gibbons said his transition team on transportation matters came up with the idea of selling water rights under state highways to help cover the estimated $3.8 billion shortfall in construction funding.

But according to state transportation and local and private water company officials, no statewide inventory exists that details the quantity and location of water rights the Nevada Department of Transportation owns under its highways.

Estimates are that the state might not own more than 6,000 acre-feet of water, with much of it in rural areas in Northern Nevada where there is little demand to purchase the rights.

At the current selling price of $10,000 to $20,000 per acre-foot, perhaps up to $120 million could be brought in. That's a small share of the funding needed to build 10 superhighways between now and 2015. Most of the highways would be built in Clark County, including two projects each costing more than $1.2 billion -- widening Interstate 15 and U.S. Highway 95.

A 2001 study by Stantec Consulting found there potentially are about 3,000 acre-feet of available water rights under highways and streets in the Reno-Sparks area.

"It is an asset the state can tap into and perhaps assist in the funding of these road construction projects," Gibbons had said, estimating the value of the available water rights would come "pretty doggone close" to the $3.8 billion needed.

But the Transportation Department does not know what water rights it owns, or even whether it acquired water rights when it purchased land for highways and rights of way, according to its spokesman, Scott Magruder.

Patty Wade, the co-chair of Gibbons' overall transition team, said the governor was looking for new ideas to fund highway projects.

"If $60 million or something else is the number, then it is still $60 million or some other number," she said. "We wanted novel, innovative ideas that didn't raise taxes. One was to begin looking at NDOT water rights."

The agency has contracted with HDR Engineering to complete a $500,000 study by this summer to identify the water rights it owns. The Transportation Department owns 5,500 miles of highways and streets in Nevada.

There are 326,000 gallons in an acre-foot, which is almost a one-year supply of water for two Las Vegas Valley homes.

The idea of selling the water rights to finance highway construction was raised -- and then put aside until the study could be completed -- last year by the Governor's Task Force on Transportation.

Task force member Daryl Capurro, then the executive director of the Nevada Motor Transport Association, suggested the Transportation Department sell water rights.

"The information I received when I made the inquiry was NDOT had something like 4,000 to 6,000 acre-feet of water rights, most in the Truckee Meadows," said Capurro, who has retired from the transport association. "I never suggested it would be the complete answer to the funding shortfall. But if is brings in $100 million, maybe $200 million it wold be part of the overall solution."

Capurro said Monday he sees no reason the state should hold onto the water rights. But the HDR Engineering study is a first necessary step and well worth the cost, he added. The consulting firm will have to do an extensive search of titles back to the 1930s.

"You have to research deeds," Capurro said. "It took me two months of research just for 30 acre-feet."

State Engineer Tracy Taylor doubts there are substantial water rights in the Las Vegas Valley. Most would be in the Truckee Meadows or along rivers such as the Humboldt in Northern Nevada, he said.

"The water rights would be where there was irrigation in the past," Taylor said. "There was not a lot of irrigation in Las Vegas."

Because of the uncertainty about whether water rights are available, Las Vegas Valley Water District spokesman J.C. Davis said his agency would not comment on whether it would be interested in buying water rights.

"We need more specific proposals before we could respond to it," Davis said. "I am not sure we have made any water rights purchases out of the Las Vegas Valley groundwater basin."

Taylor said the Transportation Department's rights are existing water rights that could be sold and transferred to a buyer. There would be no need to seek his approval during formal hearings to acquire the rights.

"It is a title issue," he said. "There is a process that is used by everyone, cities, private individuals. The value of water rights varies throughout the state."

Tracy and municipal and private water company representatives said the water rights are dispersed throughout the state and there probably would not be enough water available in any one basin to make an inter-basin transfer profitable.

Lori Williams, Truckee Meadows Water Authority general manager, said her agency does buy water rights in the Reno area, having paid as much as $30,000 to $45,000 per acre-foot. But the value now has dropped to the $10,000 to $20,000 range.

She added she doubted there would be much value to water rights in Winnemucca, Elko and other communities along Interstate 80 because there is little growth.

"There is a market in this basin," added Williams, who serves on Gibbons' water transition team. "But we don't have a lot of developers clamoring at this point. If you were thinking you could fund a huge project with water rights sales, my position is that probably is not so."