Numerical modeling of long term reservoir sedimentation in semi-two dimensional manner

Abstract

Reservoir sedimentation reduces the benefits from the storage of fresh water. The volume and distribution of sediment deposition must be predicted for a long term reservoir operation plan. Either or both experimental and numerical modeling can be applicable for an evaluation of reservoir sedimentation. Because sedimentation occurs along entire reservoirs and throughout the reservoir life span, a one-dimensional numerical sediment transport model, GSTARS, was considered in this study. Even though the model is not a truly two or three dimensional one, the model has capability of simulating channel geometric change in a semi-two dimensional manner using the stream tube concept. In this study, the effect of the number of stream tubes on the performance of the numerical simulation was analyzed using 14 years of real reservoir sedimentation data, and reasonable results were produced with three stream tubes. The densities of the deposited sediment depend on the reservoir operation scheme, especially for clay and silt. It was found that the predicted results vary with the density, and the prediction with various density with respect to location is required for a study reach where reservoir and river regions exit together.