Effect of spatial adaptation measures on flood risk: study of coastal floods in Belgium

Abstract

Flood risk in coastal zones is projected to increase due to climate change and socioeconomic changes. Over the last decades, population growth, increases in wealth, and urban expansion have been found to be the main causes for increasing losses in coastal areas. These changes may, however, be offset by appropriate management measures. The main goal of this study is to assess future changes in flood risk and the effectiveness of flood risk adaptation measures for the coastal zone in Flanders, Belgium. In order to achieve this, we set up a modeling framework to assess the future flood risk of the Belgian coast including climatic and socioeconomic projections, and used this model to assess the effectiveness of two spatial adaptation measures: compartmentalization and land-use zoning. In this modeling framework, a land-use model, an inundation model, and a damage model were combined to calculate expected annual damage. Results show that without adaptation measures, future flood risk would increase substantially. Compartmentalization would result in an average flood risk reduction of approximately 50 % for both the baseline situation and future scenarios. Land-use zoning would result in smaller flood risk reductions, averaging between 6 and 10 %. Except for the most extreme climate change scenario, compartmentalization would successfully offset the combined adverse effects of socioeconomic growth and climate change on flood risk for this case study. For both compartmentalization and zoning, large differences have been found in their effectiveness at the local level, implying that the choice of adaptation measures should be tailored to local characteristics.