Mapping social vulnerability to floods. A comprehensive framework using a vulnerability index approach and PCA analysis

In recent years, the analysis of social vulnerability to floods became an integrated part of the flood risk management process, the strategies and policies developed focusing on risk reduction methods that increase the resilience of vulnerable communities. Therefore, reliable and robust social vulnerability approaches are needed, which is also highlighted by the increasing socio-economic growth and climate change related effects that can lead to unpredictable consequences. The use of vulnerability indices is the most widespread methodology that allows the identification of the most vulnerable communities and the understanding of the factors that increase vulnerability to floods. However, due to the lack of a standard procedure, the existing studies are often characterized by uncertainties related to subjective selection of indicators, lack of inclusion of all vulnerability dimensions, equal or subjective weighting methods, and reduced number of variables due to data unavailability. The present paper is addressing these gaps by developing a comprehensive methodology approach which: includes a large set of indicators that are selected considering the local socio-economic context, includes the hazard dimension in the analysis considering flood related variables, and applies objective weighting methods based on the Principal Component Analysis (PCA) method. Furthermore, flood vulnerability maps are developed using Geographic Information System (GIS) tools, to provide a rapid and easy way to identify highly vulnerable areas. The results showed that the integration of statistical methods and GIS tools in the social vulnerability index construction provides a better understanding of the factors that increase the social vulnerability and offers an overview of the mitigation and adaptation measures that must be implemented by authorities in order to improve the flood risk management.