The project involved construction of a system for collecting and transporting water 30,000 meters (18.6 miles), from Lake Mead to Las Vegas. Lake Mead is the largest man-made lake in the United States and is formed from the Hoover Dam, which blocks the path of the Colorado River.
Scope of Work
A 4,500 meter (2.8 miles) long tunnel, with an excavation diameter of seven point two meters (23.6 feet), was constructed at the bottom of the shaft under the lakebed. This was a unique project for the Ballard team due to the extraordinary pressures at the tunnel boring machine head. Pressure was anticipated to reach fourteen-point five bar, and all equipment was to be constructed with a design working pressure of seventeen bar (247 pounds per square inch) – the highest in the world to date. This was one of the first projects in the world that was prepared fully for saturation operations. Ballard was key to securing the proper federal variances.
Ballard compressed air workers, saturation divers, man lock tenders, medics, along with other specialized labor and consultants who were on-call for the duration of the project. Ballard provided a job specific hyperbaric manual to assist with state variances and performed the saturation system commissioning and integration of the Tunnel Boring Machine (TBM) system. A mobile control van was fabricated by Ballard to allow for the distribution and monitoring of breathing gasses, video feeds, pressure readings, gas analysis, and more.
At a transfer rate of approximately four point five million cubic meters per day, the project increased the supply of water for drinking and domestic use in the urban area of Las Vegas.
Client: Herrenknecht / Dual Mode
Location: Las Vegas, NV
Design Pressure: 17 bar / 247 PSI