Comparative flood damage model assessment: towards a European approach

TLDR

Flood damage models vary widely in approach and economic estimates, and their growing use for investment and planning decisions highlights the need to reduce uncertainties and develop a harmonised European approach, especially regarding the EU Flood Risks Directive. The study assesses seven flood damage models qualitatively and quantitatively using two case studies in Germany and the UK, and calls for a flexible yet consistent European framework that incorporates best practices and regional adjustments. The authors conduct a qualitative and quantitative assessment of seven flood damage models through two case studies of past flood events in Germany and the United Kingdom. Qualitative analysis reveals strong variation in modelling approaches, especially in infrastructure damage estimation, while quantitative results show that model outcomes are highly sensitive to vulnerability (depth–damage functions) more than exposure (asset values), leading the authors to caution against aggregated land use data and to emphasize adjusting asset values to regional economic conditions and property characteristics. Abstract.

Abstract

Abstract. There is a wide variety of flood damage models in use internationally, differing substantially in their approaches and economic estimates. Since these models are being used more and more as a basis for investment and planning decisions on an increasingly large scale, there is a need to reduce the uncertainties involved and develop a harmonised European approach, in particular with respect to the EU Flood Risks Directive. In this paper we present a qualitative and quantitative assessment of seven flood damage models, using two case studies of past flood events in Germany and the United Kingdom. The qualitative analysis shows that modelling approaches vary strongly, and that current methodologies for estimating infrastructural damage are not as well developed as methodologies for the estimation of damage to buildings. The quantitative results show that the model outcomes are very sensitive to uncertainty in both vulnerability (i.e. depth–damage functions) and exposure (i.e. asset values), whereby the first has a larger effect than the latter. We conclude that care needs to be taken when using aggregated land use data for flood risk assessment, and that it is essential to adjust asset values to the regional economic situation and property characteristics. We call for the development of a flexible but consistent European framework that applies best practice from existing models while providing room for including necessary regional adjustments.