ICOLD Bulletin 204, Flood Risk Assessment, examines flood risk assessment and management for dams, reservoirs and other flood management infrastructure. It reflects the shift from controlling floods to risk management and resilience. Considering climate change, human activities and hydrological uncertainties, it explains how risk assessment supports infrastructure planning and design, including protection levels, flood storage capacity and coordinated reservoir operation.

A major focus is flood risk assessment during real-time operation, accounting for forecast uncertainties, infrastructure condition and evolving risks. Beyond flood probability, assessment considers economic, environmental and human consequences, alongside the resilience of affected areas. The Bulletin presents methods for comparing risks and scenarios and adapting reservoir and infrastructure operation as flood events develop.

International case studies illustrate these principles: flood management in China’s Changjiang River basin, risk-informed flood protection and the Continuous Insight method in the Netherlands, and Norway’s Telemark watercourse system. They show how forecasting, modelling, real-time data, human expertise and coordinated infrastructure management support anticipation of extreme events, reduced consequences and better-informed decisions.