Drivers influencing the changes in the Composite Flood Vulnerability Index in the Lower Godavari Basin

The importance of studying the different dimensions of a flood disaster – hazard, exposure, resilience, and vulnerability has been highlighted in many studies. While concrete methodologies exist for estimating flood hazards and exposure, determining vulnerability remains a hurdle in flood risk assessment. Whereas the hazard and exposure analysis captures the susceptibility of physical assets, it fails to address the vulnerability of its inhabitants, which may be attributed to poverty, occupation, caste, ethnicity, exclusion, marginalization, and inequities in resource availability. Despite efforts in the mapping of flood-prone areas and developing various social vulnerability and flood vulnerability indices, there is limited understanding of the combined effect of physical and socio-economic factors on flood vulnerability. Thus, in this study, a composite flood vulnerability index (CFVI) is conceptualized to study the combined effect of physical and socio-economic factors on flood vulnerability, and the changes in the CFVI are analyzed in the floodplains of the Lower Godavari basin in India. The region between the Bhadrachalam and Konta, located on the banks of the Godavari River, experiences frequent fluvial flooding due to the backwater effect caused by the turbulence generated at the confluence of the Godavari and Sabari rivers. The study of flood vulnerability as a combination of hazard, exposure, and social vulnerability will help diagnose the cause of the vulnerability, and strategize flood mitigation efforts while ensuring social equity. Moreover, studying the spatial distribution and temporal changes in the composite flood vulnerability index at a regional scale can help design a combination of structural flood control and adaptive measures.