Risk Assessment of Earth Dam Overtopping Using System Dynamics and Monte Carlo Simulation (case study: Hajilarchay Dam)

Risk assessment of the hydraulic structures is one of the serious concerns of researchers especially in earth dams. Using uncertainty and risk analysis, it is possible to use uncertain parameters in mathematical equations for designing. This paper considers the different uncertainties related to flood and wind with various return periods and uses system dynamics to evaluate overtopping risk on earth dams in order to mitigate this risk and then increase the earth dam s operational life. In order to evaluate risk in proposed model, we use Monte-Carlo simulation (MCS) method with different iterations. In this research, system dynamics is used as a simulation OF overtopping risk in the Hajilarchay dam, Northwestern Iran. The results show the effectiveness of system dynamics in earth dams overtopping risk assessment with different parameters effecting the overtopping risk. Moreover, opening the bottom outlet of the Hajilarchay dam could cause 12 percent reduction in overtopping risk. Also overtopping risk obtained from the MonteCarlo simulation is one to two percent greater than Latin hypercube sampling and with less simulation running time. It can be concluded that system dynamic is very effective tool for evaluation and calculation of overtopping risk of dams and is easier and faster than other common numerical methods like Programming.