In engineering design, uncertain conditions are improved by setting conservative hypotheses and applying high safety factors. Decision making in this field is seen as a complex process accompanied with uncertainties. Nevertheless, in risk assessment methods, functional relationship levels and evaluation of safety levels with probabilistic methods are emphasized. Using such processes, the designer can define several scenarios to evaluate the risks governing. Consequently, beneficiaries of the project will be able to make appropriate decisions regarding safety and economical considerations. This decision-making process can be implemented through the combination of value management and risk analysis models. Considering the current uncertainties in dam engineering, the implementation of the risk analysis models in water resources projects seems to be essential. Reliability analysis is one of the methods, which can be used to quantify risks. In order to perform the evaluation process of the efficiency of risk analysis methods in dams, a case study, namely, No. 4 Chahnimeh dam which is located in south of Iran has been selected. The results of reliability analysis for the piping phenomenon which are assessed by the consultant, show a conservative approach with low risk in the design of this dam. For the, evaluation of seepage control, two scenarios are specified. In the first scenario, piping risk is considered high; and in the other scenario, the risk is taken to be acceptable. Based on the obtained results, it can be concluded that use of risk analysis for improvement of the decision-making process can be a fundamental strategy.
