The impacts of uncertainty in the predicted dam breach floods on economic damage estimation

In the risk analysis for dam safety assessment, the economic damages due to flooding resulting from a dam failure should be estimated precisely to quantify the potential risks of the dam as the dollar damage and calculate the cost effectiveness of various dam risk reduction measures proposed to improve safety of the dam. However, the common approach of estimating economic damages with the relationship between flood depths and percent damage values at the damage centers are subject to uncertainty, because some degrees of uncertainties are involved in the flood depths predicted by the dam breach flood routing analysis models and defined percent damage values in the relationships. This paper identified the degrees of uncertainties in the predicted economic damages by considering both the amount of the uncertainty in the predicted flood depths and the percent damage values in process of the economic damage estimation. The amount of uncertainty in the estimated flood depths were obtained from the uncertainty analysis on the dam breach flood routing analysis results using a computational model, while the possible variation ranges of the percent damage values were assumed based on the recommend values. The main purpose of this study is to contribute to define the uncertainty in the estimated risks of an existing dam. However, the approaches introduced by this study may be utilized to identify the amount of uncertainty in the other types flood damages due to a dam failure.