Quantifying Flood Risk Evolution Under Reservoir Operations: A Comprehensive Framework for Hazard, Vulnerability, and Loss Risk

Abstract

Floods are among the most devastating natural disasters globally, underscoring the need for robust flood risk assessment methodologies. Reservoirs significantly alter flood risk patterns by regulating the spatial and temporal dynamics of flooding. However, current research on flood risk under reservoir operations primarily focuses on static risk probabilities, lacking a quantitative analysis of the evolutionary process of flood risk, which limits targeted risk management strategies. This study proposes a comprehensive framework for quantifying flood risk evolution under reservoir operations, integrating hazard, vulnerability, and loss risk assessment. Key issues including multi-site flood combinations, hydrograph shapes, damage vulnerability, and reservoir operating rules are systematically integrated. The framework is validated using a case study of three reservoirs on a tributary of the Huai River in eastern China, employing single, parallel, and multiple reservoir configurations. Results demonstrate the framework's ability to quantitatively elucidate the evolution of flood risk under different reservoir operations. Comparative analyses reveal the influences of reservoir structure, operating rules, and spatial location on flood risk patterns, providing targeted insights for risk mitigation. The proposed framework offers implications for flood risk assessment and supports the planning and management of flood control projects.