Las Vegas Sun

October 25, 2014

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CHASING LAKE MEAD’S WATER: PART 3 OF 3

FRIDAY: The Colorado River and Lake Mead helped build the modern American West, but that foundation is far from solid as we struggle to live with a shrinking lake.

SATURDAY: Don't be frightened by the sexually confused fish, but there are growing concerns about the kinds of pollution getting into Lake Mead.

Because in the desert it's all about the water, the future of Southern Nevada is inextricably tied to the future of Lake Mead.

We are growing more dependent on the lake to sustain our economy at a time when water levels are dropping and other states are competing for its water as well.

And we send our wastewater and toxic urban runoff into the lake, worsening pollution levels that are growing more concentrated because there's less water to dilute it.

This is the new predicament, and on both fronts we are losing ground.

It can be fixed, experts say, but only with lots of money and engineering know-how.

Even though the lake was created in 1936, Las Vegas didn't need to tap it until 1971, when it sunk a huge pipe into the lake to suck out water. Until then, the Las Vegas Valley survived on its ground water.

At the time that first intake was placed in the lake, the 300,000 acre-feet annually that Las Vegas is allocated seemed like an almost inexhaustible bonanza.

But the combination of growth and drought, and the resulting drop in the lake's level, has shaken our confidence that Lake Mead can sustain us.

The lake's level is measured by its elevation above sea level. At its peak in 1983, it was full at 1,229 feet. Today, it's at 1,127 feet. That is the lowest level since the upstream reservoir, Lake Powell, filled in the late 1960s.

The lake level started dropping in 2000, triggering plans by the Southern Nevada Water Authority to sink its single straw deeper into the lake to reach the better-quality water at lower depths. The $7 million job was completed in 2004, with the new intake situated at 1,050 feet - about 77 feet below the current surface level.

The Water Authority four years ago completed the project, saying it would last more than 20 years. The $2 billion undertaking included construction of a second intake, dubbed the second straw, deep into the lake and a system of pipelines keep the water coming uphill, where it is treated for consumption.

The impetus for the No. 2 intake was growth, not drought, but circumstances have changed. The drought has introduced a new set of dynamics.

This past summer a $14 million project was completed to connect the two existing straws - Intake No. 1 and No. 2 - to allow the Water Authority to keep pumping water to a treatment facility even when the water dropped below the No. 1 intake.

That step was meant to buy time while engineers looked for longer-range solutions to stabilize the water level. Now, with the level still dropping, backs are against the wall. It's not a familiar position.

The Water Authority is, at a cost of $16 million, lowering the older intake's huge pumps and motors by another 30 feet. That will enable them to operate as long as the water level is at least 1,080 feet above sea level. That provides a 47-foot cushion, based on the lake's current level.

But the steps taken so far are small compared to the one coming up - a third straw.

Construction should begin in late 2007 and last about five years.

"The expectation is that Lake Mead will decline for several more years even with normal flows," says Marc Jensen, engineering director for the Water Authority. "That led us to the conclusion that we needed another intake that was much deeper."

The project is budgeted at $650 million, but Jensen says the agency is estimating it will grow to about $800 million - a number roughly equal to that, in 2006 dollars, of the cost to build Hoover Dam.

This new intake will be situated at 860 feet - almost 200 feet below Intake No. 2, at a level at which lake water is at its best quality, Jensen says. Coincidentally, the new intake would be in the heart of the lake's "dead pool" - the level at which lake water is too low to be released downstream through Hoover Dam. Even at that level, the lake would still hold 2 million acre-feet, about 652 billion gallons .

The new intake will be a huge engineering project. Although the existing intakes are at Saddle Island - now, ironically, a peninsula because of falling water levels - the third intake will require three miles of tunnel underneath the lake.

"These are big projects by any scale," he says. "It's a major challenge for the professionals we have engaged, very exciting from an engineering and construction point of view."

"Without No. 3, we might lose a large part of our capacity to deliver water to the community," Jensen says. "If we were willing to gamble, we would be putting the community at risk and that doesn't seem like a responsible position."

As important as the future of Lake Mead and the Colorado River is to Las Vegas, the stakes for neighboring Arizona and California are, in one sense, higher. Both states and Mexico depend on releases from Lake Mead. California takes 4.4 million acre-feet annually; Arizona, 2.8 million acre-feet; and Mexico, 1.5 million acre-feet.

Nevada takes a comparatively measly 300,000 acre-feet each year. But on the other hand, urban Southern Nevada is almost totally dependent on Lake Mead for water.

In February, Interior Department officials are scheduled to release new guidelines on how the seven states and federal water managers will respond to looming shortages of Colorado River water. One element of the guidelines will consider how to add more water to the Colorado River system, including Lake Mead.

One goal is to eliminate non-native plants such as salt cedar, also known as tamarisk, that by some estimates consumes as much river water in a year as do all of the residents of Southern Nevada.

More snow would help, too. So some have proposed cloud seeding to boost snowfall in the Rocky Mountains.

Getting more water into Lake Mead from upstream is part of the equation to stabilize the lake; the other is to conserve its water downstream.

One tack is to seal irrigation canals so water won't seep into the ground before reaching crops. Less wasted water would allow less water release from Lake Mead. To that end, President Bush on Dec. 20 signed a bill into law designed to sweep aside environmental protests to the lining of large irrigation canals near the Mexican border, a process that should save about 70,000 acre-feet of river water.

In what is perhaps a more significant move for Southern Nevada, that law also allows the Southern Nevada Water Authority to pay for a storage reservoir near the Mexican border to catch river water that would otherwise flow into Mexico. The Water Authority will pay the $84 million construction costs and, in exchange, have permission to take 280,000 acre-feet of water out of Lake Mead over a period of seven years - enough to accommodate about 120,000 households.

The federal Bureau of Reclamation, which would manage the reservoir, has not announced a construction schedule. But no one doubts its importance.

Interior Secretary Dirk Kempthorne spoke to hundreds of lawyers and engineers at the annual meeting of the Colorado River Water Users Association in Las Vegas on Dec. 15. The drought, and how to divvy up the shortages, was the principal topic of discussion among the assembled members of local, state and federal water agencies from across the Colorado River basin.

Kempthorne, whose department oversees the National Park Service and Bureau of Reclamation - which runs Hoover Dam and manages the Colorado River system - told the assembled hundreds of water users that at stake was nothing less than the future of the West.

"From a legal and political standpoint, the difficulties we face in negotiating and constructing this future are arguably as daunting as the challenges faced by the engineers who harnessed the river," Kempthorne said. "It will take more than perseverance to meet these challenges. It will take a determination that failure is not an option."

Launce Rake can be reached at 259-4127 or at [email protected]

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