The construction of cascade reservoirs is associated with considerable uncertainty in sedimentation in the fluctuating backwater area of the terminal reservoir and poses challenges to water safety. The sedimentation characteristics under the influence of multiple factors in the main urban area of the Chongqing river section were analyzed as a case study for the operation of cascade reservoirs in the Jinsha River via the utilization of a large dataset spanning back to the normal storage of the Three Gorges Reservoir. The results of this study indicate that, owing to factors such as upstream water, sediment inflow, reservoir operation, and river sand mining, this river section experienced deposition on the sand bars and erosion in the main channel. The rate of sedimentation increased with sediment inflow, peak flow rate, and duration, while the location of sedimentation shifted as the concentration ratio changed. These results may provide technical support not only for the operation of the Three Gorges Reservoir, but also for the governance of the fluctuating backwater areas of other cascade reservoirs.

The tailings reservoir is a major facility in mine production, but also a potential dangerous sourse. So predicting the dam break flow and sediment transport process in the downstream, which contribute to the construction and safety management of the tailings reservoir, has the vital significance. In this paper, a horizontal 2-D dam break flow and sediment numerical model is established, which is applied in the dam break of Liushujing tailings reservoir, and it is proved that the model can simulate the process of flood submerging and sediment depositing well.