Evolution of the Chenglingji–Datong Channel in the Middle and Lower Reaches of the Yangtze River and Its Drivers

In recent years, the water–sand composition of Yangtze River channel has changed due to influence human factors, especially construction water reservoirs such as Three Gorges Project. Changing conditions have a long-term impact on shaping river morphology in middle and lower reaches River, erosion retreat local sections caused great harm embankment projects. This paper focuses evolution mechanism from Chenglingji Datong over past 31 years. Landsat remote sensing images 1989–2019 were used extract interpret bodies, shorelines, central bars study area using Modified Normalized Difference Water Index (MNDWI) combined with visual interpretation. We near analysis morphological characteristics river, channel, selected typical for comparative analysis. found out that overall change between 1989 2019 was small horizontal direction, but significantly. Considerable scouring occurred vertical direction. Combining hydrological meteorological data, we investigated effects Dam, instream sand mining, boundary conditions, vegetation cover both sides riverbanks, aspects storm flooding watershed river. The indicated geological implementation bank protection project, improvement made riverbanks more resistant scouring. However, heavy rainfall floods, operation Reservoir, mining activities make susceptible Based calculation slope rate accumulated volume, it runoff is mainly influenced by precipitations, while transport affected activities. shows natural anthropogenic affect equilibrium state river’s sediment varying degree.