Dam safety decision-making: Combining engineering assessments with risk information

A decision recommendation justification matrix is proposed as an effective tool for presenting decision justifications to decision makers. The matrix comprises ratings to summarize the outcomes of traditional engineering assessments and risk assessments. The approach can be adapted to any dam owner's unique decision context and any national or jurisdictional engineering assessment practice or system of risk evaluation guidelines, including ALARP. Three decision types are addressed: setting tolerable risk goals for individual dams, identifying a risk reduction pathway for a portfolio of dams, and managing residual risk on an on-going basis. Examples of either the traditional engineering approach or a risk assessment approach leading to more stringent risk reduction justifications are illustrated.