[This article belongs to Volume - 53, Issue - 05]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-14-11-2021-89
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Title : Delayed Response Law of Sedimentation in the Three Gorges Reservoir
ZHANG Wei, LI Xin, REN Jinqiu,

Abstract :

Hysteresis is one of the important characteristics of automatic adjustment of river system, while there are few studies on the law of sediment delayed response in the Three Gorges Reservoir (TGR). Based on the delayed response model, the measured data were analyzed and the delayed response model was modified by considering the sediment concentration and sediment particle size in order to construct the delayed response model in accordance with the characteristic of sediment deposition in TGR. Firstly, the changes of water and sediment conditions and sediment deposition characteristics since the impoundment of TGR were counted, and the influence of cascade reservoirs in the upper Yangtze River was analyzed. In order to simulate and analyze the sedimentation delayed response law in different periods of TGR, the existing model was used and modified. Based on the existing and modified response model simulation results, it can be seen that 1) The modified response model can better simulate the sediment deposition process of TGR after the impoundment of cascade reservoirs because of the consideration of sediment concentration and sediment particle size. 2) After the impoundment of cascade reservoirs, the fluctuation range of inflow and sediment decreases, the sediment inflow of TGR is more concentrated in flood season, both of which make the channel adjustment rate increase, the delayed response time of sediment deposition in TGR is shortened from the early 4 years to the early 3 years. 3) After the impoundment of cascade reservoirs, the influence weight of sediment concentration on the sediment deposition process increases, while the influence weight of flow and water level in front of dam decreases. By using the modified model, it can be seen that the inflow of sediment concentrates more in the flood season, which make the delayed response time of sedimentation in TGR shorten, and the influence weight of sediment on the sediment deposition increases.