Developing a Depth–Damage Function for the Built Environment to Support Disaster Risk Assessment in India

Flooding is a natural disaster that causes severe economic and social disruptions worldwide, with India particularly vulnerable due to its geographic and climatic factors. This paper overcomes the limitations of existing models such as the global flood depth–damage function, which in most cases lack regional adaptability and fail to capture local socioeconomic and geographical specificities. Utilizing empirical data from the 2018 Kerala, India, floods, this study proposes a novel relationship between flood depth and rebuilding costs. This proposed depth–damage function is more adaptable and can be used more widely for diverse economic and geographic contexts. This approach thus highlights the importance of integrating empirical data into theoretical models that improve the assessment of flood damages. Validation against the 2013 Uttarakhand, India, floods confirmed its applicability across India. Therefore, the proposed depth–damage function would act in India as a reference point for flood damage assessment and also support the Global Infrastructure Risk Model and Resilience Index (GIRI) portal of the Coalition for Disaster Resilient Infrastructure (CDRI). Although robust, regional refinement across different regions will enhance its transferability. This is in accordance with global initiatives like the integrated risk management and resilience building in the face of climate change.