+ click to enlarge
Southern Nevada Water Authority

Las Vegas is not known as a dry town but 20 years of booming growth has left it parched. The drought-wracked desert city has been the nation’s fastest growing for over a decade, according to the U.S. Census Bureau. The Las Vegas Valley has added 480,397 new residents since 2000, the population equivalent of Oakland, Calif. Jeff Hardcastle, Nevada’s state demographer, ex­pects another 1,548,010 residents, or 82.5% more people than today, by 2026. Newcomers have local officials scrambling to meet the region’s water needs, which the Southern Nevada Water Au­thority now estimates at 400,000 acre-ft more annually by 2025.

“We have had a series of record years, virtually unending growth since 1983,” says Ron Lynn, building director for Clark County Development Services. “This cycle starts with residential building, which drives commercial expansion.”

But the water level in Lake Mead, which supplies 90% of SNWA’s 1,200-million-gallon-per-day maximum capacity, is 110 ft lower than it was seven years ago. In September, the lake was at 1,110 ft, or 49% of capacity, making its primary raw water intake dangerously close to inoperable. Clark County, to help conserve, requires reclaimed water on new golf courses and eliminated decorative fountains in commercial developments. Its equally arid Arizona neighbor, Phoe­nix, which has seen a similar 20.2% population in­crease since 2000, implemented conservation measures with great success. Unlike Las Vegas, Phoe­nix is better poised to deal with a prolonged drought.

Related Links:
  • Las Vegas Looks Beyond the Colorado To Slake Its Thirst
  • Recharged Aquifer Keeps Wichita�s Water Flowing
  • “People can live a low-water use lifestyle while still meeting the needs of our economy,” says Ray Quay, assistant director of Phoenix’s Water Services Dept. “We are in a completely different situation than in Las Vegas. They don’t have stable water conditions, where­as we have a much closer to sustainable water supply.”

    Las Vegas ratcheted up its conservation initiatives in 2004. New homes, for example, are no longer permitted to have front lawns and backyards are limited to 50% grass landscaping. SNWA additionally pays businesses and homeowners $2 per sq ft to tear up turf and replace it with low-water alternatives. The agency re­ports that the eight-year-old program has converted 93 million sq-ft worth of sod for an estimated 18-bil­lion-gallon water saving.

    + click to enlarge
    Lake Meade
    (Image: NASA/Jesse Allen, based on data provided by the Landsat 7 Science Team)

    But that is still not enough. So the agency bought 1.25 million acre-ft of water from Arizona for $330-million, or $264 per acre-ft. The deal, inked in 2001 and amended in 2004, paid the state $100 million in 2005, along with 10 an­nual payments of $23 million beginning in January 2009. In exchange, SNWA can withdraw an additional 20,000 acre-ft starting this year, ramping up to 40,000 acre-ft by 2011. The water agen­cy also receives return-flow credits since the withdrawals are taken from Lake Mead.

    “It does not eliminate the need for us to continue our conservation efforts or develop water supplies that are independent of the Colorado River,” says SNWA General Manager Pat Mulroy. “However, this agreement does provide the bridge we need to help insulate the residents of southern Nevada from ongoing drought.”

    Las Vegas hopes to create more insulation by paying $84 million to build the 8,000-acre-ft Drop 2 Reservoir in Imperial County, Calif., 25 miles west of Yuma, Ariz. The project lets SNWA claim unused water deliveries from Imperial Valley farmers via the Colorado River. The agency will receive 280,000 acre-ft of water for its financial contribution. The U.S. Bureau of Land Management’s Yuma Office is overseeing the reservoir's construction, which now remains in the early environmental impact stage.

    “The water resource conditions that we’re seeing are affecting the entire region,” says Paul R. Brown, president of Cambridge, Mass.-based CDM’s public services group. “We’re seeing not only conservation becoming a fundamental element of everyone’s management strategy but increased water-use efficiency, which could mean recycling water for ir­rigation and nonpotable resources. Everybody is concerned about the flows of the Colorado River.”

    Move In. New housing sprouts in southern Nevada, but water restrictions now govern development
    New housing sprouts in southern Nevada, but water restrictions now govern development.

    Early on, Phoenix successfully used a series of dams, groundwater aquifers and reservoirs to bolster its water supplies. Like other western states, Arizona relies on flows from the Colorado River for a portion of its water supplies. But unlike Las Vegas, Phoenix additionally receives one million acre ft-annually from the Salt River Project (SRP), a Tempe-based public utility that supplies 60% of the city’s water. In 1903, settlers formed the Salt River Valley Water Users’ Association, still a part of today’s SRP, and pledged over 200,000 acres of farm land as collateral for a government loan to build Roosevelt Dam. In 1996, it underwent a $430-million upgrade, raising the height of the masonry dam to 357 ft, sheathing it in concrete and expanding Roosevelt Lake’s storage capacity by 20%. It forms the cornerstone of the Salt River Valley’s water storage and delivery system, along with a 1,300-mile water delivery system, three more Salt River dams and two Verde River dams. Phoenix’s Water Services Dept. additionally reclaims over 80% of its wastewater, reusing it for irrigation, recharging aquifers and powerplant cooling.

    SNWA now is working on a $2.9 billion capital improvement program through 2014 to bolster water reserves, with Parsons, Pasadena, Calif., as program manager. This has created a bonanza of drought-related work for engineering and construction firms, with HDR Inc. the most recent participant. Last month it  beat out 17 rival firms to land a $4-million contract to design the initial phase of a 300-mile, 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.

    Booming. Las Vegas has been the nation’s fastest growing city but its growth depends on water
    Michael Goodman/ENR
    Las Vegas has been the nation’s fastest growing city but its growth depends on water..

    Omaha-based HDR will conduct hydraulic and surge analyses for more than 200 miles of large diameter pipeline, five pumping stations with forebays, four hydroelectric stations, a 40-million-gallon buried terminal reservoir and a future treatment plant.

    “Eighteen firms bidding for one proj­ect is unheard of,” says John Plattsmier, HDR’s project manager. “It’s a pretty aggressive market now, and SNWA is a good client to work for with interesting projects. There is a lot of [water] conveyance work around the country. This project has been on our radar screen for at least two years, like many other companies’.”

    The line’s second phase entails design for a 75-mile initial section of 78-in. and 84-in. pipe, a flow-control station and a regulating tank. Other pipeline work includes six, 3-million-gallon regulating tanks and 14 groundwater production well sites. ENSR International, Westford, Mass. is performing the environmental impact statement, which is ex­pected to finish in 2009.

    “We are going to have dozens of construction contracts,” says Marc Jensen, SNWA’s engineering director who is ex­ploring design-build and construction management at-risk in order to fast-track construction. “Our intention is to be poised to start construction in 2009 once the environmental clearances have been achieved.”
    Yet the first section of pipeline will not be operational until at least 2012, which isn’t soon enough. SNWA’s 600-mgd...