LAS VEGAS – Facing dwindling water supplies, Western states are struggling to capture every drop with dam and diversion projects that some think could erode regional cooperation crucial to managing the resource.

Against that backdrop, eight Western governors met in Las Vegas this weekend to address regional water issues, and water managers from seven states arrive this week to work on ways to ensure 40 million people in the parched Colorado River basin don’t go thirsty.

Gary Wockner, a conservationist with the Denver-based advocacy group Save the Colorado, said there’s already jostling amid the fear of empty buckets. “Everyone is trying to get the last legal drop of water,” he said.

Colorado River Water Users Association representatives deny there’s discord at their table.

“Fifteen years of drought has tightened everything. But I don’t see this as people are getting ready to fight,” said Jeff Kightlinger, general manager of the Metropolitan Water District of Southern California. That agency is dealing with drought on the Colorado River and in the Sierra Nevada and Northern California.

Nevada Gov. Brian Sandoval hosted Western Governors’ Association counterparts from Colorado, Idaho, Montana, New Mexico, South Dakota, Utah and Wyoming this weekend to consider several issues, including water. Two days of drought workshops follow.

“The motto is: We save the system as a whole,” said Pat Mulroy, longtime general manager of the Southern Nevada Water Authority in Las Vegas and now a senior policy fellow with the Brookings Institution.

“If we get into, ‘I’m going to win,’ and, ‘You’re going to lose,’ there won’t be a winner,” Mulroy said.

But Wockner said Colorado, Wyoming and Utah are considering dams and diversions in the mountains to capture water they’re entitled to before it reaches the Colorado and flows to the deserts.

New Mexico has plans to divert and store water from the Gila River for cities and farms before it flows into Arizona and empties into the Colorado River near the Mexico border.

“Diversions extract water from the system,” said Jack Schmidt, professor of watershed sciences at Utah State University. He just completed three years studying the Grand Canyon for the U.S. Geological Survey. “More water use and more water retention in the upper basin means less water flowing through the Grand Canyon to the lower basin.”

In Las Vegas, which virtually relies on water from Lake Mead, officials are making plans to add a $650 million pumping facility to draw from the reservoir even if levels drop below 1,000 feet above sea level. That’s the line at which Hoover Dam’s hydroelectric turbines would be idled.

The Southern Nevada Water Authority already is drilling an $800 million tunnel to tap water from the bottom of the lake.

At 900 feet — so-called “dead pool” — the river would end at Hoover Dam. Nothing would flow downstream.

The lake reached its high water mark in 1983 at 1,225 feet.