The Las Vegas Valley has enough water to support 1 million more residents, and it should be able to weather at least the next 20 years before any permanent new supplies are needed, according to the Southern Nevada Water Authority's revised 2015 resource plan.
Current supplies could be stretched even further — decades more perhaps — through increased conservation and some help from Mother Nature on the Colorado River, the annual report concludes.
Authority board members adopted the updated Water Resource Plan Thursday after a brief presentation and discussion.
John Entsminger, the agency's general manager, described the 58-page document as a blueprint for how the authority will secure the community's water supply for the next 50 years, no matter how quickly Southern Nevada grows.
"We don't dictate growth. We give the community the tools it needs to be what it wants to be," he said.
Board members adopt the plan each year, but the document hadn't undergone a major update since 2009, "and six years in the water planning process is a long time," Entsminger said. He called this year's report a "wholesale revision."
There was also an effort made to make the plan easier for the general public to read, said Julie Wilcox, deputy general manager of administration.
Even under the worst case envisioned by the document — a combination of the deepest cuts imaginable on the Colorado River coupled with an unexpectedly large population surge — the authority won't need to start bring new resources on line for the next 20 years.
That scenario, which Entsminger called the ultimate stress test for the community's water supply, envisions worsening drought conditions that force an almost 15 percent cut in the valley's Colorado River allocation at the same time the population is growing at a rate 40 percent higher than the what UNLV's Center for Business and Economic Research is projecting.
"We don't believe this is realistically going to happen," Entsminger said.
A more likely scenario involves more modest population growth — 1 million more residents by 2045, 1.5 million more by 2065 — and some drought-related shortages on the Colorado, which could force the region to dip into its water reserves within the next 15 to 20 years and start developing new supplies by 2060 or so, according to the plan.
Entsminger said the community could buy itself another decade or more with additional — and he thinks realistic — conservation gains.
Thanks to the amount of conservation already achieved, he said the authority now has "very healthy reserves" totaling roughly 1.5 million acre-feet of water banked in various locations, including Lake Mead, Arizona, California and in the groundwater aquifer underlying the Las Vegas Valley.
That's enough water to supply the community for more than seven years at current consumption levels, Entsminger said.
In separate action Thursday, board members signed off on a plan to lease 150,000 acre-feet of water from its reserves to California in the coming year. Pending approval from its board, the Metropolitan Water District of Southern California will pay the authority almost $44.4 million for the water.
The authority could either keep the cash and let California keep the water, or repay some or all of the money some day and get a proportional share of water in return.
"We'll have access to the water when we need it," Entsminger said.
In the meantime, the $44,375,000 from Southern California's largest municipal water supplier would be placed in the authority's rate-stabilization fund and saved for a rainy day — or more likely a dry day.
"We're not proposing any particular use for it now," Entsminger said of the money.
Now for the bad news: None of the future water resources envisioned by the plan are a sure bet, and the ones likely to produce the most water could wind up costing of billions of dollars.
Chief among those new resources is groundwater the authority plans to tap across rural Nevada and pipe to Las Vegas. The controversial project was first proposed more than 25 years ago, and it continues to face stiff opposition and stubborn legal challenges at the state and federal level. Then there's the price: some $15 billion including full financing costs according to the authority's own estimates.
The authority's plan also mentions ocean desalination as a future resource, though precisely how that would work and what it would cost has yet to be determined. It could involve partnering with Mexico on a coastal desalting plant or two in exchange for some of that nation's Colorado River water.
Experts have said such partnerships with California are far less likely because that state is already struggling to build desalination plants along its heavily regulated coast to meet its own rising demand for water.