The treatment of interval uncertainty in dam safety risk-informed decision making

Author(s) D. Zhou, R.C. Donnelly, S. Hassan, M. Leng, D. Danielson
Published in the Canadian Dam Association 2023 Annual Conference Proceedings, 22-25th October 2023 in Winnipeg, Manitoba.


Dam safety risk analysis in its simplest form is based on estimates of the consequence and probability of occurrence of an undesirable event. However, in many instances these variables cannot be accurately determined due to aleatory and/or epistemic uncertainties leading to assessments that may not provide a true representation of risk. The use of the interval probability method is proposed as one means of dealing with uncertainties. For example, the Reclamation Consequences Estimating Methodology [1] defines the potential loss of life resulting from a given dam breach event as an upper limit (LOLU) and a lower limit (LOLL) which can lead to conflicting conclusions with respect to the risks posed by a dam. The paper proposes a method to deal with such potential conflicts and discusses practical problems associated with uncertainty, providing examples of how to resolve these problems.