A GIS-based approach to compare economic damages of fluvial flooding in the Neckar River basin under current conditions and future scenarios

Fluvial floods can cause significant damages and are expected to increase in magnitude and frequency throughout the twenty-first century due to global warming. Alongside hazard characteristics, damage potentials depend on exposure and vulnerability, which are changing in the wake of socio-economic developments. In the context of continuously evolving damage-causing factors, assessments of future changes in flood damage potentials are increasingly asked for by decision-makers in flood risk management. This study addresses this need by (a) providing a systematic review of contemporary assessment approaches to quantitatively compare direct economic losses from fluvial flooding under current and future conditions and (b) combining the reviewed approaches to an applicable methodology which is used in a case study to quantify changing flood damage potentials in the Neckar River basin in southern Germany. Therefore, a scoping study of contemporary flood damage assessment approaches supported by geographic information systems (GIS) is performed. The subsequent case study of the Neckar River prognoses a significant increase in average annual flood damages in the study area throughout the twenty-first century. The case study produces valid results with regards to current precipitation data, whereas the absence of verification data makes the validation of projected scenarios more difficult. To account for uncertainties surrounding these future projections, a nascent qualitative confidence estimation is introduced to reflect on the strength of knowledge underlying the used flood damage assessment methodology.