Development of sustainable water management strategies involves identifi cation of vulnerability and adaptation possibilities, followed by an effect analysis of these adaptation strategies under different possible futures. Recent scenario studies on water management were mainly ‘what-if’ assessments in one or two future situations. The future is, however, more complex and dynamic. It involves general trends and unexpected events in both the water and the social system. Moreover, the two systems interact: society responds to events and the state of the water system changes in response to management. In this paper we discuss a transdisciplinary approach. Key elements in the concept are (1) the model of pressure, state, impact and response, (2) the Perspectives method to consider uncertainties of social and natural systems and (3) the evaluation of the system using transient scenarios in which we consider time series of trends, events and interaction between the water system and society. The effect analysis is executed with an integrated assessment meta-model based on simple cause–effect relations and response curves