2009 Owner of the Year: Southern Nevada Water Authority

By Tony Illia

Southwest Contractor’s annual Owner of the Year award for the Southwest region is selected by the editorial staffed based on nominations from industry professionals. This year’s honoree, SNWA, was chosen based on its volume of work, commitment to the community, sustainability and vision for the future.

The Southern Nevada Water Authority has quenched the Las Vegas valleys’ thirst since 1991. That’s no easy feat considering the desert region has experienced boom growth alongside a prolonged drought.

Construction crews erect a head frame and hoist structure over the third raw water intake tunnel access shaft for Southern Nevada Water Authority, 2009’s owner of the year. Photo courtesy SNWA

SNWA is an 18-year-old, seven-member group agency formed to address the area’s long-term water needs, with the Las Vegas Valley Water District serving as its manager. The water level in Lake Mead, which supplies 90% of SNWA’s 900-million-gallon-per-day maximum capacity, is over 100 ft lower than it was in 2000.

“In 2004, the magnitude of the drought on the Colorado River became quite evident, so we engaged in a conservation plan,” says Marc Jensen, SNWA’s director of engineering. “The community has responded very well.”

Clark County has mandated that required reclaimed water be used on new golf courses and eliminated decorative fountains in commercial developments. New homes, meanwhile, are no longer permitted to have front lawns, and backyards are limited to 50% grass landscaping. SNWA additionally pays property owners up to $1.50 per sq ft to tear up turf and replace it with low-water alternatives.

The program is yielding results. Despite a population increase of 400,000 people between 2002 and 2008, Southern Nevada’s annual water consumption dropped by nearly 21 billion gallons during that span.

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But it’s still not enough.

The U.S. Bureau of Reclamation predicts that Lake Mead will sink to its lowest point since May 1965 this summer. By July, the Colorado River reservoir on the Nevada-Arizona border will drop more than 13 ft from its current level of 1,105 ft above sea level, which is less than half of its capacity.

While a federal shortage declaration isn’t currently projected, should one happen in the future it would force Nevada and Arizona to reduce their combined water use by 333,000 acre ft a year in the first of three shortage levels, says Robert Walsh, external affairs officer for the Bureau of Reclamation’s Lower Colorado Region. The majority (320,000 acre ft) would be borne by Arizona, but Nevada would lose 13,000 acre ft, or about enough water for 26,000 average homes. SNWA’s 600-mgd first water intake at Lake Mead could become inoperable.

“This year’s snow pack isn’t above normal, so we don’t expect the lake level to come up,” says Patricia Mulroy, SNWA’s general manager. “Complex problems require innovative solutions.”

SNWA is responding with a multipronged approach that entails a $2.9 billion capital improvement program through 2014 to bolster water reserves. The agency’s 50-person engineering department oversees a series of interconnecting projects that entails coordinating several engineers and contractors. Parsons of Pasadena, Calif., is the program manager.

“SNWA's leadership and engineering staff [are] ... firm but fair in their dealings with construction contractors and consulting engineers,” says James Foss, vice president of CH2M HILL, an Englewood, Colo.-based firm that has worked with SNWA since the early 1990s. “[They are] dedicated to the public interest, tireless in pursuit of their mission to provide reliable and safe potable water to their customers.”

In 2004, Baynard of Nevada performed a $6.4 million, 144-ft-long intake extension amid dropping water levels at Lake Mead. Photo courtesy SNWA

The dedication led SNWA to embark on its biggest project to date: a third water intake at Lake Mead. In March 2008, Vegas Tunnel Constructors LLC - a joint-venture of S.A. Healy Co., Lombard, Ill. and Impreglio SpA, Sesto San Giovanni, Italy - won a $447 million, design-build contract to build the intake.

“It’s not going to add to capacity,” Jensen says. “It’s insurance in case our current intakes become inoperable. It will also draw water lower ensuring a better water quality.”

Construction entails a 20-ft-diameter, 15,000-ft-long, concrete-panel-reinforced tunnel under the lake bed. The contracting team is purchasing a hybrid custom-built tunnel boring machine from Herrenknecht AG of Schwanau, Germany, created specifically for the project.

The TBM will be able to operate in both open and closed modes, meaning the drill face is pressurized, for more efficient ground and water control, says Jim McDonald, Vegas Tunnel’s project manager. The TBM will have a trailer installing 2,500 supporting concrete rings, each weighing 3,500 tons. Each ring consists of six separate pieces that will be manufactured onsite.

Other tunneling work entails a 16-ft-diameter, 60- to 80-ft-deep water intake shaft and a 32-ft-diameter, 600-ft-deep access shaft along Saddle Island’s western shore line.

“We expect to have about 200 people onsite during the peak of construction activity,” McDonald says. “The TBM will take about four months to assemble and test.”

The intake tunnel has a 1,571-day project schedule that’s expected to finish in July 2012. There are four separate projects associated with the new intake, including a 600-mgd pumping station; 14-ft-wide, 16-ft-tall connection to the second intake; 120-in.-diameter discharge pipeline from the pumping station to the Alfred Merritt Smith Water Treatment Plant; and a large power substation and lines. The entire raw water intake program is expected to run $817 million, and finish by early 2013.

SNWA also bought 1.25 million acre ft of water from Arizona for $330 million. The deal, inked in 2001 and amended in 2004, paid the state $100 million in 2005, along with 10 annual payments of $23 million that started in January. In exchange, SNWA was able to withdraw an additional 20,000 acre ft starting in 2007, ramping up to 40,000 acre ft by 2011. The withdrawals are taken from Lake Mead.

The water level at Lake Mead, which supplies 90% of SNWA’s capacity, is over 100 ft lower than it was in 2000, and is forecast to drop another 13 ft by this summer. Photo courtesy SNWA

“It does not eliminate the need for us to continue our conservation efforts or develop water supplies that are independent of the Colorado River,” Mulroy says. “[It] does provide a bridge we need to help insulate the residents of Southern Nevada from the ongoing drought.”

SNWA is creating yet more insulation by paying for roughly half of the $172 million, 8,000-acre-ft Drop 2 Reservoir in Imperial County, Calif., 25 mi west of Yuma, Ariz. The project lets the agency claim unused water deliveries from Imperial Valley farmers via the All-American Canal.

SNWA receives the right to withdraw at least 400,000 acre feet of Colorado River water beginning in 2011, at a maximum rate of 40,000 acre ft per year until 2036. The Bureau of Reclamation is overseeing reservoir construction.

A joint-venture between Ames Construction Inc., Phoenix, and San Diego-based Coffman Specialties Inc. won the $98.3 million construction contract. The project broke ground in September and is expected to finish in October 2010.

Southern Nevada is pursuing additional cushion by building a rural groundwater pipeline. Tentative plans call for a 300-mi, 150-mgd buried water pipeline that will transfer groundwater from rural northeast White Pine and Lincoln counties to Las Vegas. The bond-financed project will cost at least $2 billion to complete. In late 2007, SNWA awarded a $4 million contract to HDR Inc., Omaha, Neb., to design the pipeline’s 75-mi-long initial phase.

ENSR International, Westford, Mass., is currently performing the environmental impact statement for the Bureau of Land Management, which is expected to wrap-up this year. The soonest it would be operational is 2012.

“The Authority has been able to complete all of its capital projects successfully and with minimal change orders during construction because of their fair and equitable approach to problem solving, their highly skilled engineering staff, and the continuous input and support of their operations and maintenance team,” Foss says.

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