Numerical analysis of propagation characteristics of sediment peak and its implications for the Xiluodu reservoir

Reservoir construction alters the hydrodynamic characteristics of the flow and sediment regimes, resulting in the enhancement of the hysteresis effect between the flood and sediment peaks. In this study, a 3D numerical model was adopted to investigate the propagation characteristics of sediment peak and the management method of reservoir sediment release. The results indicate that the incoming flow rate and the storage water level have a great influence on the propagation time of the sediment peak, and the incoming flow rate has a large influence on the attenuation rate of the sediment peak while the storage water level and the incoming suspended sediment concentration have a little effect on the attenuation rate of the sediment peak. An empirical formula based on inflow rate, water level elevation, water depth and length and storage capacity of reservoirs was established to predict the lag time between the flood and sediment peaks. The asynchronous movement between the incoming flood and sediment peaks has a clear influence on the propagation characteristics of the sediment peak. The hysteresis effect of the flood and sediment peaks can be fully utilized by reservoir managers to reduce reservoir sedimentation and improve sedimentation distribution.