Uncertainty Analysis of Reservoir Sedimentation

Significant advances have been made in understanding the importance of the factors involved in reservoir sedimentation. However, predicting the accumulation of sediment in a reservoir is still a complex problem. In estimating reservoir sedimentation and accumulation, a number of uncertainties arise. These are related to quantity of streamflow, sediment load, sediment particle size, and specific weight, trap efficiency, and reservoir operation. In this study, Monte Carlo simulation and Latin hypercube sampling are used to quantify the uncertainty of annual reservoir sedimentation and accumulated reservoir sedimentation through time. In addition, sensitivity analysis was performed to examine the importance of various factors on the uncertainty of annual reservoir sedimentation. The proposed procedures have been applied to the Kenny Reservoir at the White River Basin in Colorado. The uncertainty of annual reservoir sedimentation and the effect of each uncertain factor, taken individually and in combinations, on the uncertainty of accumulated reservoir sedimentation through time have been examined. The results show that annual streamflow and sediment load are the most important factors determining the variability of annual reservoir sedimentation and accumulated reservoir sedimentation. In the case of Kenny Reservoir, the uncertainty expressed by the coefficient of variation can be on the order of 65% for annual reservoir sedimentation and 39% for accumulated reservoir sedimentation volume.