In recent decades, advances in formal risk analysis of hydrological hazards affecting dam safety has led to the development of methods and techniques capable of comprehensively addressing the hydrological risk. These developments recognize that the overtopping failures of dams are caused not always by extreme floods exceeding the design discharge capacity, but often by equipment failures, and human errors in planning and implementing the operation can also lead to overtopping during more-frequent and smaller events.13 This kind of comprehensive risk assessment method is covered in more detail by the main Good Practice Note on Dam Safety.