Evolving Flood Risk Mitigation Strategies Using Hydrodynamic Modeling Linked with Hydroeconomic Optimization for Burhi Gandak River

Flood risk assessment is critical for minimizing the economic loss resulting from flood damages, mitigating adverse socio-economic impacts and sustainable water resource management in the flood-prone regions. The flood is becoming a major world-wide concern due to recent events of disastrous floods in several countries, and it is gaining high significance because of climate change. The present study is aimed to present a methodological framework that combines hydro-economic evaluation with the hydrodynamic modelling for assessing flood risk and evolving structural and non-structural adaptative strategies for mitigating flood in riverine condition. This framework has been employed to the Burhi Gandak River basin in India, a region frequently affected by severe flooding leading to significant agriculture, infrastructural, and social disruptions.  Employing a hydro economic optimization framework, the research integrates hydrological modelling, economic evaluation, and optimization techniques to assess and manage flood risk. It also examines direct and indirect losses due to flooding and potential gains from mitigation strategies. The hydrological data, land use patterns, and socio-economic indicators were analysed to simulate flood scenarios. The approach combines flood inundation model with economic cost-benefit analysis, capturing both under varying rainfall intensities and catchment conditions. The results show that the optimization techniques can be applied to identify cost-effective strategies, including structural measures such as levees, and retention basins and non-structural measures such as early warning systems, land use policies for managing flood disaster effectively. Results. reveal that a balanced combination of structural and non-structural interventions can significantly reduce flood damage while optimizing resource allocation. This study provides a decision-support tool for policymakers to prioritize investments and implement adaptive strategies that enhance resilience against flooding in the Budhi Gandak basin. The integration of hydro economic evaluation not only improves the flood risk management but also contributes to the sustainable development of vulnerable regions.

Keywords: Flood risk, Flood mitigation, Optimization, Hydrodynamic modelling, Hydro economic framework.