Southern Nevada Water Authority Stage II Reliability Upgrades Project: Providing Reliability to Central Las Vegas Water Supply through a New Interconnect Pipeline

The Southern Nevada Water Authority (SNWA) has initiated the Stage II Reliability Upgrades (S2RU) Project in response to the increasing risk posed by aging yet critical conveyance infrastructure which supplies a significant portion of water to central Las Vegas. The Project aims to fortify the water supply system by introducing redundancy and reliability through the construction of the new Monthill Pumping Station (Monthill PS) and an accompanying 66-in. diameter interconnect pipeline. This pipeline will augment existing pumping station (PS) capacity by providing a dependable redundant route for supply of treated water, both when the existing pumping is in operation, and as replacement capacity during scheduled maintenance periods. The Monthill PS will deliver up to 90 million gallons per day (MGD) through this new pipeline and will not only alleviate the pressure on existing pumping facilities, but also enhance system efficiency and reliability by establishing a two-way flow between existing transmission laterals. The S2RU Project is not without challenges. This paper addresses the significant obstacles and unique design solutions associated with the design of the Monthill PS and interconnecting pipeline, including such challenges as a tight urban residential pipeline corridor alignment, coordination with existing utilities, a trenchless roadway crossing, and shallow groundwater. Through these design solutions that will be utilized to produce construction documents along with teamwork between SNWA and the design engineer, this project will ensure a reliable and robust water supply for the vibrant heart of Las Vegas.