Advanced Scenario Analyses and Planning for Future Water Supply Challenges
D. A. Sampson1 & R. Quay1
1Global Institute of Sustainability, Decision Center for a Desert City, Arizona State University
City level water policy and management decisions are typically based on past experience and best estimates of future conditions. This management approach heavily relies on “craft skills” that are acquired through long, place-based experience. Decisions using this approach are typically based on a limited number of socio-economic, water supply, and water demand projections, often only a single one. Under traditional scenario planning a small set of scenarios are compared to one another in order understand their differing impacts. Human cognition typically limits this to three to five scenarios. However, some complex and highly uncertain issues require more than five scenarios. We suggest that water governance at the municipal level could greatly benefit from water planning tools that use advanced scenario planning. Under advanced scenario analysis, quantitative or qualitative methods are used to reveal patterns and associations among scenario metrics for a large ensemble of scenarios. From this analysis, a smaller set of heuristics that describe the complexity and uncertainty revealed provides a basis to guide planning in an anticipatory fashion. Our advanced scenario framework (ASF) uses our newest WaterSim model—WaterSim 5—to enable a wide spectrum of probable water futures. In this coupled model, potential population growth dynamics and water supply and demand projections at the water provider level are levered with new policy options that permit evaluation of short- and long-term alternative governance strategies. This analysis examines the probable influence of drought and climate change on the implementation and response of the assured water supply program.