Lake Mead water level will be trigger for pipeline

LAS VEGAS - Opponents of a proposed pipeline to tap groundwater across eastern Nevada now have one more way to fight the project: Pray for the drought to end on the Colorado River.

For the first time, the Southern Nevada Water Authority has established a direct link between its multibillion-dollar pipeline project and the shrinking water level at Lake Mead.

Actually it's more than a link; it's a trigger.

If the surface elevation of the reservoir behind Hoover Dam falls another 21 feet, the water authority board in Las Vegas will be asked to give the go-ahead to construct the pipeline.

Declaring an action point is the newest addition to the authority's Water Resource Plan, which plots how the Las Vegas area's wholesale water supplier expects to keep taps running amid unprecedented drought on the Colorado.

Board members already have approved the pipeline concept and signed off on efforts to secure water rights and environmental permits. But they have never voted to build the project.

That decision will come if, or perhaps when, the surface of Lake Mead sinks to 1,075 above sea level - a low-water mark not seen since 1937 when the reservoir was being filled for the first time.

Water authority General Manager Pat Mulroy doesn't know when that point might be reached.

Current projections by the U.S. Bureau of Reclamation call for Lake Mead to remain above 1,075 for at least the next two years. But the lake level is expected to slip below 1,092 feet in elevation in July for the first time since March 1965.

The problem, Mulroy said, is that bureau projections are based on average river flow, and the Colorado has been anything but average for the past 10 years.

From 1999 to 2008, the river had about 66 percent of its normal inflow, most of which comes from melting snow in the Rocky Mountains. Over that same period, lakes Mead and Powell, the two largest man-made reservoirs in the United States, lost about half their total volume.

Elevation 1,075 on Lake Mead could arrive as early as next year if the drought deepens, Mulroy warned.

The trigger point was set at 1,075 to give the agency time to reach its closest groundwater holdings in rural Nevada, Mulroy said.

If the lake level falls to 1,050 feet above sea level, the authority will be forced to shut down one of two intakes it uses to draw drinking water from the reservoir. Las Vegas gets about 90 percent of its water from Lake Mead.

The surface now stands about 1,096 feet above sea level. The last time it was that low was in 1965, when much of the Colorado River's flow was being withheld upstream to fill Lake Powell for the first time.

Mulroy said it will take about three years to build a pipeline from Las Vegas to the Delamar and Dry Lake valleys, the first two Lincoln County basins from which groundwater will be drawn.

From there, the pipeline is expected to push into Cave Valley in Lincoln County and Spring Valley in White Pine County.

The authority also is seeking permits to pump more than 16 billion gallons of groundwater a year from Snake Valley, or enough to serve about 100,000 average Las Vegas homes. A state hearing on those applications is scheduled for September 2011.

The groundwater project is expected to take 10 to 15 years to build, Mulroy said.

When it is done, the network of pipes, pumps and reservoirs is expected to stretch about 300 miles north of Las Vegas and cost from $2 billion to $3.5 billion, according to water authority cost estimates now several years old.

Opponents expect the pipeline plan to cost billions of dollars more and deliver less water than the authority expects. Some fear that large-scale groundwater pumping will threaten wildlife and the livelihoods of ranchers and farmers in the arid valleys of eastern Nevada.

The authority's 2009 Water Resource Plan, which the board adopted May 21, calls for Las Vegas to eventually tap 134,000 acre-feet of groundwater a year from eastern Nevada.

The plan calls for that water - enough for almost 270,000 homes - to be put to use by 2020, though it "may be needed sooner if drought conditions persist or intensify," the document states.

Critics argue that the drought is used as a smoke screen for the pipeline's real purpose: to fuel unfettered development in Southern Nevada.

"It could be just a Trojan Horse to allow more unrestrained growth in Las Vegas," said Bob Fulkerson, executive director of the Progressive Leadership Alliance of Nevada, an advocacy group that opposes the groundwater development project.

Of course, authority board members could vote against building the pipeline when the time comes.

Mulroy said the board's decision will come down to a question of whether the community can risk losing access to some of its Lake Mead supply before the pipeline goes on line.

Elevation 1,075 is significant for another reason. It is the legal threshold for a shortage on the Colorado River - a federal designation that would force Nevada and Arizona to reduce the amount of water they draw from the river.

Nevada would lose 13,000 acre-feet a year, roughly the amount used by 26,000 average households. Arizona would lose more than 10 times that amount.

Water authority officials long have said the pipeline is not about sustaining growth, but protecting the community from extended drought.

In that respect, the new trigger means the pipeline project might never be built if the river rebounds and Lake Mead remains above 1,075.

Mulroy isn't optimistic about that. As chief of the agency charged with keeping water flowing to Las Vegas, she gets paid to plan with pessimism.

"If we can avoid building it, we won't build it," Mulroy said of the pipeline. "But we haven't had a lot of luck on the Colorado River lately."