Research on Riverbed Adjustment Response of Jingjiang Reach Under the Change of Flow and Sediment

Abstract

Abstract. According to the hydrological and sediment data before and after the impoundment in the Three Gorges Reservoir and the measured topographic data of Jingjiang Reach, the article analyzes the response mechanism of erosion and deposition of riverbed in Jingjiang Reach for flow changes, suspended sediment recovery and bed material compensation, makes a judgment of the terrain adjustment trend of the reach in the future. The main conclusions are as follows: After the impoundment of Three Georges Reservoir, the low flow has increasing and streamwise recovery of suspended load strengthen the scouring ability of the overall Jingjiang Reach. After the impoundment of Three Georges Reservoir, the Jingjiang Reach shows conforming and cumulative erosion; the low flow channel is the principal part of riverbed scouring.

Vertical Distribution of Suspended Sediment Concentration in the Unsaturated Jingjiang Reach, Yangtze River, China

“…Before the impoundment of the TGD in 2003, the middle Yangtze River was considered a quasi-equilibrium channel with limited bed deformation and fluctuations in the suspended sediment concentration (SSC) [10]. With the completion and operation of a series of reservoirs on the main stem and tributaries of the upper Yangtze River, the lower reaches, e.g., the Jingjiang (JJ) Reach, have experienced a significant change in sediment transport regimes, mainly from quasi-equilibrium to unsaturation [9,[11][12][13]; this change has resulted in bed scouring [14], bank collapse [4], and a decrease in the SSC [15].…”