Decision making under uncertainty: A new paradigm for water resources planning and management

Climate change challenges water managers to make decisions about future infrastructure and the adequacy of current supplies before the uncertainties of the climate models and their hydrological impacts are resolved. Water managers thus face the classic problem of decision making under uncertainty (DMUU). The aim of DMUU is not to be paralyzed by uncertainty, but to highlight and use it to better manage risk. Strategies for DMUU include scenario planning, exploratory simulation modeling, robust decision making, and anticipatory planning and governance. These tools imply a new role for social scientists in the fields of water science and engineering and a new relationship between water science and the practitioner community. Examples are drawn from Phoenix, Arizona, and the US Southwest for DMUU support tools and strategies for science-policy engagement. Simulation experiments for Phoenix reveal challenging, but feasible, strategies for climate adaptation in the water sector for all but the most dire future climate conditions.