To support strategic water management, a new scenario method is being developed to explore possible non-linear long-term developments of the coupled water-society system. This method entails a policy-game in which players compete over future water management policy. The game involves the formation and dynamical change of advocacy coalitions in which players holding similar perspectives on water management cooperate. Shifts in the positions and / or relative power of the various coalition perspectives - under various scenario drivers and shock events - are assumed representative for possible real-life future shifts of world view and management style at the societal level. The game involves various modelling tools. Players interact w...