Preface: Towards sustainable flood risk management in the Rhine and Meuse river basins

Flood risk (defined as a result of flood probability and potential damage) along Rhine and Meuse rivers is expected to increase in two ways: A. Climate change will cause a significant increase in the probability of extreme floods (according to a majority of climate change scenarios). B. The potential damage of floods (the level of investments in areas at risk) is doubling every three decades. Moreover, the room available for improved flood risk management in the future is rapidly decreasing due to urbanisation along the rivers - this decrease in room for measures will increase the cost of future solutions. Water retention through land-use change may be useful in lowering the frequency of extreme floods in small basins, and possibly in reducing the level of ’medium-sized’ floods in large basins. At the scale of the Rhine and Meuse basins these measures have no significant effect on extreme floods occurring downstream, caused by prolonged heavy rainfall over large areas. Water retention areas along channels far upstream are only marginally more effective in this respect, though detention areas (for ’controlled retention’) can have a more significant impact. In river valleys and alluvial areas there will always remain a flooding risk. As long as flood risk management authorities focus on flood control rather than on damage prevention, spatial planning will insufficiently take into account flood risks, with the effect that the actual risk continues to rise while the public awareness of the risk decreases. This approach is not sustainable in the long term. An important consideration is also that, in the lower Rhine and Meuse basins, loss of life can nowadays be avoided through improved early warning and evacuation schemes. Flood risk management in these basins could therefore be a matter of optimisation of the costs and benefits of measures, rather than a ’fight against the floods’. Flood risk management measures can help achieve a combination of economic development and other policy targets, such as creating an ecological infrastructure and improving the quality of the landscape. For this, a comprehensive strategy for the desirable development of the river corridor as a whole should be developed. Local solutions should meet the requirements of this strategy, as well as specific local requirements. Of course, such a strategy must be supported by stakeholders - resistance from the local population to measures may be reduced by good information supply, fair compensatory measures and proper use of regulations.