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Climate change and socio-economic development result in increasing flood risk which challenges flood risk management policy making and practice. Each situation, however, is different and calls for not only understanding the natural context, but also the socio-economic and cultural context. Only then Flood Risk Management strategies can be designed that are not only 1) fit for purpose but also 2) feasible for local implementation and 3) sustainable into the future. Flood consequences that are accepted in some cultures (fatalist), may not be acceptable in other cultures (controlist). This calls for considering the local normative context in order to understand current differences in policy and practice. More importantly, the design of strategic alternatives for Flood Risk Management into the future should consider this socio-economic and cultural context as well because not every society aims for the same goals in the same proportion, nor is equally willing or capable to implement and maintain sophisticated infrastructure and dedicated institutions. Based on literature on cultural theory and national cultures, we hypothesized that acknowledging socio-economic and cultural differences would allow to better appreciate the rationale of current flood risk management policies and practices in different parts of the world. By analysing cases related to Deltares projects abroad, we explored whether these factors explain the main differences observed. Based on this preliminary exploration, we propose a shortlist of factors to consider when designing future flood risk management strategies tailored to local socio-economic and cultural contexts.

Water managers and researchers strive towards the same objective: the improvement of the quality status of water bodies. However, there is still a gap between the results of academic studies on water systems and the information currently used in water management. The Water Framework Directive (WFD)-Explorer, a modular toolbox which supports integrated water management in a river basin, attempts to bridge this gap. The toolbox analyses the impact of different restoration measures on river ecology based on expert rules embedded in this simulation environment. The strengths and weaknesses of the toolbox have been tested on the Zwalm River basin in Flanders, Belgium. The ecological status of streams in the basin spans the whole range of nearly pristine headwaters to severely impacted river stretches further downstream. Considering the key bottlenecks in the Zwalm basin and the user-driven ecological status objectives, several water quality and physical habitat restoration options have been proposed to meet the European Water Framework Directive goals. The positive impact of restoration measures on the ecological quality ratio (EQR) for macroinvertebrates appeared to be the highest for measures affecting the nutrient inflows and thus chemical water body characteristics. However, the spatial scale on which the WFD-Explorer modelled the impact of physical habitat restoration may have been too coarse to generate reliable results concerning such restoration measures. Hence, the combination of the WFD-Explorer results with those of more detailed studies on physical habitat restoration impacts might be a promising approach to reliably support decision-making implementation of the WFD. Copyright © 2008 John Wiley & Sons, Ltd.

Current flood protection policies in the Netherlands are based on design water levels. This concept does not allow for a proper evaluation of costs and benefits of flood protection. Hence, research is being carried out on the introduction of a flood risk approach, which looks into both the probability of flooding and the consequences of flooding. This research is being carried out within the framework of a major project called the Floris project (FLOod RISk in the Netherlands). To assess the probability of flooding the Floris project distinguishes different failure modes for dikes and structures within the dike ring. Based on a probabilistic analysis of both loads and resistance the probability of failure is determined for each failure mode. Subsequently the probabilities of failure for different failure modes and dike sections are integrated into an estimate of the probability of flooding of the dike ring as a whole. In addition the Floris project looks into the different consequences of flooding, specifically the economic damages and the number of casualties to be expected in case of flooding of a particular dike ring. The paper describes the approach in the Floris project to assess the flood risk of dike rings in the Netherlands. One of the characteristics of the Floris project is the explicit attention to different types of uncertainties in assessing the probability of flooding. The paper discusses the different starting-points adopted and presents an outline on how the Floris project will deal with uncertainties in the analysis of weak spots in a dike ring as well as in the cost benefit analysis of flood alleviation measures.