Decision-Making for Water Security: Negotiating Competing Uses

Water security is concerned with the ability of water systems to deal effectively with environmental and social change.  At the heart of this challenge is the capacity to make decisions about water in the face of uncertainties about climate, land use, population growth, global economic change, and lifestyle trends and in settings where people hold profoundly different attitudes about the value, meaning, and use of water.  Traditional optimization models for water resource management are giving way to exploratory simulation tools that enable users to delve into a range of climate futures and policy options—to decide what kind of future they want and what they are willing to give up to get there.   Ideally, these models are both products and processes—products in the sense that they integrate the best science about climate, hydrology, land use, demography, and economy and processes in that they are created in an iterative and collaborative process with stakeholders.  This paper will highlight efforts of the Decision Center for a Desert City at Arizona State University to develop WaterSim 4.0 to simulate water shortage conditions in Phoenix under climate change, population growth, urban design, and water policy scenarios and to engage it for decision analysis, scenario planning, and climate adaptation.  Interaction with stakeholders reflects inevitable trade-offs between future growth, preferred lifestyles, and the risk of future shortage.