A novel expert opinion-based approach to compute estimations of flood damage to property in dense urban environments. Barcelona case study

Abstract

A certain acceptable level of risk in a major drainage system must be established since urban areas cannot be made entirely free from pluvial flooding. Among the diversity of flood risks in urban areas, direct damage to property has been extensively studied. A novel model approach (SFLOOD) to estimate flood damage to property in urban areas has been developed and presented herein. The model was conceptualised according to the knowledge of an insurance surveyor, acquired over many years on flood economic losses appraisals. It is a micro-scale-, depth-damage- and GIS-based model where water depth is the only hydrodynamic variable considered as a damage driver. The model testing has been conducted through the direct comparison of computed damage and damage appraisals provided by the Spanish public insurance company, Consorcio de Compensación de Seguros (CCS), for three actual flood events that occurred in Barcelona (Spain). Although a variety of uncertainties related to the flood damage estimates have been revealed here, the model is able to predict the order of magnitude of the actual damages according to the results obtained.