Facing the worst drought on record in the Colorado River Basin, as lake levels continue to fall, the Southern Nevada Water Authority (SNWA) is building a low lake level pumping station to ensure Las Vegas and Southern Nevada maintains access to its primary water supplies in Lake Mead. Lake Mead water levels have dropped more than 40 m (131 feet) since the drought began in 2000. The new pumping station will allow SNWA to pump water from Lake Mead from an elevation as low as 267 m (875 feet) above sea level into the water treatment facilities and further on to provide water to the city of Las Vegas and neighbor community area.
Development of the pumping station consists of constructing an 8m (315 in) – diameter access shaft at more than 152 m (498 feet) depth. At the bottom of the access shaft, an 1150 square-meter (12379 square feet) underground cavern is excavated. The cavern, known as a fore bay, will connect with 34 vertical shafts — each 152m (498 feet) deep and 1,8m (72 inches) in diameter — to accommodate the station’s 34 submersible motor pump sets which 30 of them will be manufactured and installed by Indar. So far, 20 low lift submersible motor pump sets (LLP) plus 10 high lift submersible motor pump sets (HLP) will be delivered by INDAR
As María Elena Rodríguez, Water Engineering Director says, “the drop of Lake Mead made it necessary to install pumps in such depth, making traditional vertical turbine solution no feasible to operate reliable in those depths”.
Each of those 30 Indar pumps is rated at 4732 m3/h (20,835 USgpm) with 132 (433 ft.) and 212 m (695 ft.) of head respectively providing a total capacity at the pumping station of more than 150.000 m3/h (900 MGD). “These are more than 250 bath tubs every second”, as Indar´s project manager Dirk Wulf states.
The pumps are operated through submersible motors at 13.800 V motor raging 2350 and 3881 kW (3150 and 5200 HP respectively), getting the required energy right from the hydro power plant at the close Hoover dam. Pumps, motors, riser pipes and well heads are made of stainless steel 316/316L in order to guarantee a long service life and to reduce the impact onto the water to a minimum.