Historically, flood risk has been one of the major threats to dam safety, particularly because of the potential for overtopping and the consequences of dam failure for downstream communities, infrastructure, and the environment. ICOLD has published several bulletins addressing this issue. However, assessing and managing flood risk remains challenging due to limitations in the quantity and quality of hydrological data, technical and financial constraints, changes in catchment and downstream conditions, climate change, and physical or operational limitations that may restrict improvements to flood safety measures.

This bulletin focuses on recent developments in data sources and methodologies for estimating extreme floods for dam safety purposes. It highlights the growing availability of regional and global hydrological information and encourages greater international cooperation, recognising that hydrological processes are global in nature. Particular attention is also given to uncertainty in extreme flood estimation. The bulletin is the result of an international collaborative effort involving experts from several countries, including Alan Warren, Navin Gautam, Peter Hill, Zoran Micovic, Emmanuel Paquet and Jeff Smithers.