Perspectives on flood management in the Rhine and Meuse rivers

Flood management of the Rhine and Meuse is surrounded by major uncertainties. The central question is then: given the uncertainties, what is the best management strategy? Moreover, flood management cannot be considered independently from other river functions such as nature, agriculture, inland navigation and landscape values. This raises the need for integrated scenarios that consider possible futures in a coherent and consistent way. In the present project a scenario study was carried out in which physical modelling has been combined with socio-cultural theory. The focus of the study was on flood risk management. Existing climate, land use and socio-economic scenarios, as well as water management strategies have been structured using the Perspectives method. This resulted in integrated scenarios for water management, each representing a different view of the future, together with the corresponding water management style. These were put in a scenario matrix with combinations of world views and management styles, where these both match and mis-match. Using a suite of existing modelling tools the implications of each scenario for the water systems were evaluated. Finally, a comparison of different water management styles under different possible futures was made, showing the risk, cost and benefits of different strategies. The scenario analyses demonstrate that-at the scale of the entire Rhine basin-the influence of climate change on extreme floods is much stronger than the influence of land use changes. Flood risk management in the lower river deltas should not fully rely on flood mitigation measures in the upstream basin. It also becomes clear that no flood risk management strategy is superior in all respects and in all circumstances and that safety versus societal costs is really a policy dilemma: win-win situations cannot always be attained. Under changing climate conditions, the present-day type of management in the lower river reaches runs the risk of becoming an expensive attempt to fully control flood risk problems, while trying to avoid real choices, without actually solving the problems in a long-term view. Copyright (C) 2004 John Wiley Sons, Ltd.