Abstract:
The delayed response of sedimentation is a phenomenon commonly encountered in the fluvial processes of rivers,while previous studies on the sedimentation of the Three Gorges Reservoir (TGR) give little consideration. A delayed response model of sedimentation is established considering sediment inflow and pool level to investigate the recent sedimentation characteristics at the TGR. Based on the measured data during 2003-2017 and the delayed response model,characteristics of water and sediment inflows,as well as characteristics and delayed laws of sedimentation in the flood seasons are comprehensively analyzed. The results indicate that the TGR exhibits the characteristics of large (low) water inflow and large (low) sediment inflow,and sedimentation in the flood seasons tended to increase in conjunction with the rise in pool levels during 2003-2012. There was a consistent relationship between the water and sediment change,and sedimentation in the flood seasons decreased owing to the operation of cascade reservoirs during 2013-2017. Accumulated sedimentation in the TGR during the flood seasons are closely related to the 5 years' linearly superimposed pool level. This indicates that sedimentation in the flood season is affected not only by the current year's sediment inflow and pool level but also by the sediment inflows and pool levels of the previous 4 years.