The impact of large dams on sediment deposition and channel adjustment: a case study at the Huanghuacheng Reach in the Three Gorges Reservoir, China

Since the Three Gorges Reservoir began impoundment in 2003, drastic changes have been occurring in the Huanghuacheng (HHC) Reach, which is about 330 km from the dam. With measured data, we present a comprehensive analysis of sediment deposition and channel adjustment in this reach for the period 2003 to 2018. Results show that the reach witnessed severe sedimentation, and the channel became narrower and shallower with the mainstream shifting from the left to right branch. An empirical model is proposed to calculate the sediment deposition amount. A correlation is also established between sedimentation and reach-scale morphological parameters (width, water depth, flow area, and the ratio of width to depth).