Deposition and erosion in the fluctuating backwater reach of the Three Gorges Project after upstream reservoir adjustment  

作　　者：Yongjun LU Liqin ZUO Rongyao JI Huaixiang LIU 

机构地区：[1]Nanjing Hydraulic Research Institute, State Key Laboratory of Hydrology- Water Resources and Hydraulic Engineering, Nanjing 210029, China

出　　处：《International Journal of Sediment Research》2010年第1期64-80,共17页国际泥沙研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No 50879047 and No 50779037);China's "Eleventh Five-Year" National Science and Technology Support Program (Grant No 2008BAB29B08)

摘　　要：The construction of hydropower projects, such as Xiluodu and Xiangjiaba Reservoirs, in the upper Yangtze River will lead to variations of the incoming water and sediment conditions and in turn changes in the deposition and erosion processes in the fluctuating backwater reach of the Three Gorges Project （TGP）. In this paper, based on the water and sediment characteristics, a 2D mathematical model in the boundary-fitting orthogonal curvilinear coordinate system has been employed to predict the space-time changes of sedimentation in the Chongqing reach, part of the fluctuating backwater reach of TGP, in a period of 100 years with repetition of the 1961-1970 hydrological series with and without the construction of upstream reservoirs. The results show that in the case of natural hydrological series （NHS） without upstream reservoirs, severe deposition occurs in bays with concave bank lines, recireulation flow areas and wide-shallow reaches. In the case with the adjustment of upstream reservoirs, only a little deposition exists in bays with concave bank lines, and the amounts of deposition in the Yangtze River and Jialing River reaches are about 10-20% of those in the case of NHS. Therefore, this is helpful to maintain the effective capacity of the TGP Reservoir and utilize the bank lines of the Chongqing reach.The construction of hydropower projects, such as Xiluodu and Xiangjiaba Reservoirs, in the upper Yangtze River will lead to variations of the incoming water and sediment conditions and in turn changes in the deposition and erosion processes in the fluctuating backwater reach of the Three Gorges Project （TGP）. In this paper, based on the water and sediment characteristics, a 2D mathematical model in the boundary-fitting orthogonal curvilinear coordinate system has been employed to predict the space-time changes of sedimentation in the Chongqing reach, part of the fluctuating backwater reach of TGP, in a period of 100 years with repetition of the 1961-1970 hydrological series with and without the construction of upstream reservoirs. The results show that in the case of natural hydrological series （NHS） without upstream reservoirs, severe deposition occurs in bays with concave bank lines, recireulation flow areas and wide-shallow reaches. In the case with the adjustment of upstream reservoirs, only a little deposition exists in bays with concave bank lines, and the amounts of deposition in the Yangtze River and Jialing River reaches are about 10-20% of those in the case of NHS. Therefore, this is helpful to maintain the effective capacity of the TGP Reservoir and utilize the bank lines of the Chongqing reach.

关 键 词：RESERVOIR Adjustment of water and sediment Fluctuating backwater reach Deposition and erosion Mathematical model Chongqing reach Yangtze River Jialing River 

分 类 号：TV632[水利工程—水利水电工程] S157[农业科学—土壤学]