Faced with explosive population and business growth, arid-area cities such as Las Vegas, Nevada, are scheduling water supply projects far into the next century. The city now relies on Nevada's small share of the Colorado River and meager local renewable water supplies. Substantial deposits of ground water of adequate quality located at some distance from the population center are a possible supply option. This paper develops a model for analyzing the economic feasibility and the optimal investment path for water supply for Las Vegas. We forecasted residential, industrial, and other municipal demands and the schedule of increasing costs of the water supply options. A dynamic programming model determines the optimal groundwater pumping projects in temporal and spatial dimensions along with other static water supply projects, and determines the quantity and price of water available in the region. When groundwater pumping is a supply option, the optimal rate of groundwater usage must account for the increasing costs of pumping from greater depths. Dynamics of groundwater usage is found to alter the sequence that these projects are scheduled to met Las Vegas water demands.