Analysis of Jamishan Dam Overtopping using Rainfall Threshold Overtopping Curve and Monte Carlo Simulation

Estimation of earthfill dam overtopping risk is an important issue in computing the dam height and spillway capacity. However, estimation of dam overtopping risk using Monte Carlo simulation and considering all effective random variable is very time consuming and is an ideal variant in assessment of dam overtopping risk. In this respect, due to the mentioned weakness of regular Monte Carlo simulation, the low number of random variables were used in previous studies. In this study, new approach for assessment of dam overtopping and reduction of simulation time was developed using rainfall threshold overtopping curve and Monte Carlo simulation. Result show that the relative error of estimated risk between regular and conditional (used in this study) Monte Carlo is 6 percent but the time of simulation was reduced about 29 hours. Hence, the proposed methodology (conditional Monte Carlo) respect to regular approach is more efficient in estimation of Jamishan dam overtopping risk.