Policy design and decision criteria for sustainable water supply from the perspective of “imaginary future generations” - A deliberation experiment with policymakers in a municipality, Japan

To maintain sustainable water supply systems, it is indispensable to design relevant policies with a long-term perspective. In this paper, we present a novel approach to design policies on sustainable water supply by adopting “Imaginary Future Generations (IFGs)” which has been proven effective in generating futurability of individuals. We conducted deliberation experiments focused on envisioning future water supply services and policies with the participation of employees of the Suita City Water Works Bureau and analyzed the impacts of adopting IFGs on policy design and policymaking criteria. Based on the discussion results and questionnaires administrated to the participants, we demonstrate that the perspective of IFGs could lead to producing vary different visions of water supply system in 2050 and different policy measures compared to the perspective of current generations, due mainly to the change in the decision criteria. The results show that the method could stimulate awareness of water supply use and services at the household level by citizens and the proposal of measures based on a sense of crisis about the future. We conclude that the method could facilitate more effective and flexible policy formulation aimed at realizing a sustainable water supply system from a long-term perspective by generating futurability. • Sustainable water supply policy was discussed with a participatory approach • The method of Imaginary Future Generations (IFGs) was applied in an experiment • Adoption of IFGs influenced policy design and policy making criteria • IFGs stimulated awareness of water supply use and services at the household level • Viewpoint of “futurability” facilitated effective and flexible policy formulation