Conducting a Sensitivity Analysis for the Southern Nevada Water Authority’s Horizon Lateral Program

The purpose of the Southern Nevada Authority’s (SNWA) Horizon Lateral Program (HL Program) is to improve the reliability and operational flexibility of water delivery in the southern portion of the Las Vegas Valley for existing customers and ensure capacity to accommodate projected water needs. After navigating through the feasibility study and preliminary design phases of the Program, several key variables shifted, and a new set of driving factors emerged. The SNWA initiated a sensitivity analysis to evaluate how the changes impact the planning of the Program. The key drivers assessed were lower projected water demands, inflation, and creative water transfer solutions. A cooperative effort with local purveyors during the sensitivity analysis helped confirm and assess updated water demands and their impact on the Program. Additionally, the impacts of inflation on projected construction costs were assessed and solutions were developed to mitigate cash flow risks. Finally, the sensitivity analysis considered ways to optimize the existing system by potentially transferring water from one service area to another.