Incorporating Uncertainty and Decision Analysis into a Water-Sustainability Index

This paper describes the development and testing of a methodology to assess water vulnerability and stress called "Water Sustainability through Decision Analysis." This method uses multicriteria decision analysis to measure water sustainability through a multidisciplinary lense and includes measures of water availability, demand, and policy. Assessing water sustainability is ultimately a decision problem that involves multiple stakeholders and perspectives. Uncertainty is an important and often-overlooked aspect of water sustainability. To fill this critical knowledge gap, the water sustainability through decision analysis method accounts for the uncertainty in the input data and unknown decision-maker preferences using stochastic multicriteria decision analysis. Addressing the problem of uncertainty helps to calculate risk and bypasses the problem of unknown decision maker preferences without resorting to equal or arbitrary weights for measures of sustainability. The method is applied to eight states in the southeastern United States. Georgia ranked high in water sustainability and Texas ranked low. The results provide a single outranking index and also highlight actionable items that can improve each state's water sustainability. (C) 2015 American Society of Civil Engineers.