Photo by John Guzzon / ENR In the Las Vegas Wash (above), the weir (below) restricts heavy flows, which helps to limit silt depositions in Lake Mead. Photo by John Guzzon / ENR Related Links: The Last Straw: Lake Mead Third Intake Digs Deep Few visitors to Las Vegas are likely to realize they are using the same water as on their previous visit. The city and its environs are one of the few U.S. metro areas that reclaim nearly every drop of water that goes down the drain. After it is processed at two treatment plants south of The
Related Links: Multi-Year Bank Rehab Secures Las Vegas Wash Lake Mead Intake Project Manges Risk Proactively Lake Mead, the reservoir for drinking water in Las Vegas, is in trouble. The city and its suburbs have long been challenged by a limited water supply, but the very real effects of climate change are exacerbating and accelerating already dry conditions. The region's 2 million residents depend almost entirely on the Colorado River, yet its lake-stored flows are set to dwindle significantly in the next few decades.Located about 30 miles from the city's downtown, Lake Mead's depth has sunk to perilously low levels—
Related Links: The Last Straw: Lake Mead Third Intake Digs Deep While several monumental tasks need to be completed on the Lake Mead Intake No. 3, Erika Moonin, project manager for the Southern Nevada Water Authority, says neither its contractors nor owner anticipate future issues, thanks to preconstruction risk management. "We had a very strong approach to risk management," she says. "We had open communication meetings between the owner and the construction manager, and we had experts, including our peer-review committee."The contract also included allowance accounts that provided tunnelers leeway when dealing with "potentially variable items," mainly pre-excavation grouting and
Related Links: Drought in Western U.S. Has Water Utilities Considering a Range of Solutions U.S. Drought Monitor In the weeks since California Gov. Gerry Brown (D) issued an executive order mandating a 25% reduction in water use for all urban water users to address what scientists predict could become the worst drought in 1,000 years, the state's energy commission approved water-appliance standards that would dramatically increase performance requirements for building components such as toilets, faucets and urinals."The technology is there, and we're eager to install more-efficient fixtures in buildings," says Courtney Lorenz, director of environmental management at Skanska USA. In
Roller-compacted concrete dams have steadily taken their place in the menu of possible dam types over the past four decades, with over 650 of them completed or under construction, according to HydroWorld magazine. China is far and away the leading RCC dam builder, with 165 as of 2012; of those, 40 are higher than 100 meters. Japan, the United States, Brazil and Spain are the other most prolific RCC dambuilders.Roller-compacted concrete dams evolved in the 1970s to satisfy a particular need by dambuilders and owners. The percentage of dams built with concrete dropped steadily between 1950 and the late 1970s,
Related Links: World Bank Studies Support $10B Water Project for Dead Sea Israel and Jordan have signed a final agreement to build a scaled-back version of the Red Sea-to-Dead Sea canal project, which would include a desalination plant. The nearly $1-billion project, approved by the two countries at the end of February and sponsored by the World Bank, will serve as a pilot for the planned pipeline, which will be 10 times larger and used to pump seawater and brine into the shrinking Dead Sea.“The desalination plant and pipeline are likely to be operational in 2020 or 2021,” predicts Avraham Tenne,
Related Links: Link to USGS Feb. 24 report The U.S. Geological Survey detected changes in groundwater salinity near Florida's Lake Okeechobee following construction of a seepage barrier along the southeastern quarter of the lake. Contractors working for the U.S. Army Corps of Engineers built a cutoff wall to divert the path of water seepage discovered after hurricanes in 2004 and 2005. The flow damaged the 143-mile-long Herbert Hoover Dike, built in the 1930s around the lake for flood control.Seepage of this sort is responsible for about 20% of dam failures in the U.S., according to the Association of State Dam
Related Links: Spate of Lawsuits Flows from Nashville Inundation of 2010 Information on West Riverfront Park Plan The city of Nashville, still recovering from a devastating flood in 2010 that caused more than $2 billion in damages to Davidson County, Tenn., is planning to build a $100-million flood protection system over the next three years.City officials announced the plan on Feb. 25. The centerpiece of the program, originally unveiled in 2013, is a 2,100-ft floodwall intended to help protect the city from major floods."Like other river cities, Nashville can be protected by a floodwall system," said Metro Services director Scott
Photo Courtesy of McCarthy Related Links: Best of the Best 2014 The Tarrant Regional Water District Richland Chambers Wetlands project, near Fort Worth, is now the second-largest constructed wetlands in the U.S. Completed in October 2013, the $43-million project exemplifies a trend in water treatment in which natural systems are used to assist in filtering and improving water quality.In this case, water is diverted from the Trinity River, which is sometimes dominated by highly treated flows from a nearby wastewater treatment plant, into the Richland-Chambers Reservoir to provide additional raw-water supply. The 1,880-acre wetland system acts as a "living" filter