CARSON CITY -- Southern Nevada's top water official told legislators Wednesday that her agency must begin importing water from rural Nevada by 2015 or the Las Vegas Valley will go thirsty.

"It is the only solution the Southern Nevada Water Authority has that can meet the time frame," said Pat Mulroy, general manager of the Southern Nevada Water Authority. "We must have a backup supply to protect Southern Nevada during a long and protracted drought. We looked at everything. We must get it done by the middle of the next decade."

Mulroy told the Assembly Government Committee how her agency has applied to the state engineer for permission to pump 115,000 acre-feet of groundwater from six basins in Lincoln and White Pine counties. Most of the water is in Spring Valley, about 250 miles north of Las Vegas.

But she expressed frustration over her inability to persuade White Pine County commissioners to work toward a mutual solution.

Mulroy noted that her agency has purchased $35 million worth of ranches in White Pine County, land that it intends to keep as working ranches.

Assemblyman Pete Goicoechea, R-Eureka, said he sympathized with Mulroy but added, "You protect your own turf."

Goicoechea's district covers a vast area of Northern Nevada that reaches from White Pine and Eureka counties on the east through parts of Churchill, Humboldt, Lander, Lyon, Pershing and even parts of Washoe County on the west side of the state.

"Those people in White Pine County have been there for generations," Goicoechea said.

"They feel strongly about the water. I believe there is some water available for exportation, but not near what they want."

He said the Southern Nevada Water Authority is being "very shortsighted" by depending on Great Basin water in times of drought. If there is a drought in the Colorado River Basin, which provides 90 percent of the water to the Las Vegas Valley, then he said there probably also will be a drought in the Great Basin.

"We would all be impacted by the same drought," he said.

Mulroy was invited to speak before committee by Chairwoman Marilyn Kirkpatrick, D-North Las Vegas, who requested an update on the pipeline project.

Mulroy began the hearing by describing how "Mother Nature threw us a curve" starting in 1999 with the worst drought ever to hit the Colorado River Basin. She said states that use Colorado River water formerly relied on an annual supply of 18 million acre-feet, but now the supply is more like 13 million acre-feet. One acre-foot equals 325,851 gallons, or enough water to supply two Las Vegas Valley homes for one year.

She said that the world is experiencing climatic changes and that one of the three most affected areas is the Colorado River Basin.

While the water authority implemented conservation measures that cut annual consumption by 60,000 acre-feet, she said there is nothing more that can be done except for importing water from rural Nevada.

She pointed out that Wendover, Tonopah, Carson City, Virginia City and other rural communities already are importing water from other basins.

"That is how civilization has handled its water demand" since the time of the Egyptians, Mulroy said.

"The day of Owens Valley is over," she said, referring to an area of California east of the Sierra Nevada that was dried up and its water piped to quench the thirst of fast-growing Southern California.

"Owens Valley happened at the beginning of the last century when there were no environmental laws. Today it is very different."

Opponents to the Southern Nevada water importation plan often bring up the example of Owens Valley as why Las Vegas should not take rural Nevada water.

Mulroy pledged to keep the "ranching culture" alive in rural Nevada areas from which the agency wants to take water.

"They need to be at the table," Mulroy said of the White Pine County commissioners.

Review-Journal writer Henry Brean contributed to this report.