In a world influenced by climate change and consequently sea-level rise, extreme floods are expected to become more frequent in the future, representing a serious threat for riverine and coastal settlements. Therefore, flood protection is a large component of climate adaptation and should be closely related to other measures of climate adaptation and societal needs. In this context, SARCC (Sustainable And Resilient Coastal Cities) supports the use of integrated Nature Based Solutions into coastal management, urban planning and design, integrating them into existing infrastructure and flood defenses. This paper will focus on the strategy developed for Southend-On-Sea (UK), presenting the different approaches that were used to manage coastal flooding and make it part of a long-term large scale urban development strategy. In particular, this study estimated overtopping discharges during extreme storm conditions and analyzed their inland propagation using Delft3D FM numerical simulations. Based on these results, mitigation, and adaptation measures as a part of the spatial strategy were developed through a joint collaboration of hydraulic engineers, urban designers, maritime archaeologists and local authorities, pointing out the strength of interdisciplinary approaches for reliable and well-integrated flood protection strategies. Important highlight of the study is how flood risk management is integrated in spatial planning and how hydraulic engineering modeling is directly use as indicators to make spatial design decisions.@en

Mean sea level rise (SLR) could increase up to 2m by 2100, which would see damage caused by coastal flooding in Europe increase from €1.25bn per annum currently to €961bn in just over 80 years. Urban areas situated along the North Sea coastline are particularly vulnerable to extreme sea level rise (a combination of SLR, tide and storm surges). The main goal of this study is to assess the paradigm shift in flood risk management from reducing probability of the flood event to reducing its consequences in the city of Vlissingen, in the Netherlands. Two spatial adaptation strategies are modeled and compared by using spatial, climatic, and socioeconomic projections for the year 2100: the “Vlissings Model” and the “Spuikom Model”. The Vlissings Model is about increased coastal protection through the heightening of existing grey infrastructure by 3 m, which includes the dike and buildings constructed on top of it. The Spuikom Model is accepting and rerouting overtopping water towards an existing former backshore water basin. The study brings forth an interdisciplinary "Design & Assess" framework that brings together design strategies with flood damage models and cost/benefit analyses to compare the effectiveness of two paradigms in dealing with extreme SLR. Results show that raising the dike would ensure full protection from extreme events against an initial investment and maintenance cost of €215 mil. Accepting and rerouting overtopping water would, on the contrary, reduce the impact of the flood to €8,6 million damage and less than a hundred affected inhabitants, without requiring the construction of major infrastructure but of a flood retention basin integrated to the new urban development. On the other hand, the comparison between the two strategies remains complex in quantitative terms given the different cost-benefit assessment models for such interventions.@en