Riverbed deformation and its response to human intervention on the lower reaches of the Yangtze River

The operation of the world's largest hydropower dam, the Three Gorges Dam (TGD), has significantly influenced the middle and lower reaches of the Yangtze River (YR). However, research has not been conducted on the impact of local engineering projects on the evolution of the tidal channel of the YR. This study used historical water depth and level data to analyze the factors influencing riverbed deformation in the Nanjing reach of the tidal channel of the YR. Moreover, the effect of local engineering projects on riverbed deformation in the study area was quantitatively analyzed. Our results indicated that between 1998 and 2013, similar to 78.26 x 10(6) m(3) of sediment accumulated in the study area. The goose-head bifurcated section of this reach exhibited the most significant change in riverbed deformation during this period. Between 1998 and 2013, 46.97 x 10(6) m(3) of sediment accumulated in this section, the riverbed elevation increased by 1.01 m, and the thalweg increased by 2.78 m. Quantitative analysis of the volume of sediment accumulated in the near-bank area indicated that revetment engineering accounted for >40% of the accumulation. The results of this study provide a more accurate understanding of channel deformation in the lower reaches of the YR. Moreover, the results will improve the prediction accuracy of river channel evolution and assist in channel regulation and future local engineering construction projects.