| In the West Rapty River located in Nepal, longitudinal sediment sorting is clearly observed in a specific area. One-dimensional bed deformation analysis found it difficult to explain the sorting processes by means of an existing selective sorting theory. The study proposed a new method to evaluate the longitudinal sediment sorting processes by introducing the thickness of bed load layer and a bedload formula in which the sediment transport rate is proportional to the 2.5th power of non-dimensional tractive force. The numerical simulation results on sediment sorting in the West Rapty River show that the proposed method can reproduce the sediment sorting processes well, and reveal that coarse sediment particles can hardly be transported downstream while fine sediment particles are transported actively. |
