Changes in the backwater effect of Dongting Lake inflows on the Lower Jingjiang River after the impoundment of the Three Gorges Reservoir

Puntos clave

• This research aims to analyze the changes in the backwater effect on the Lower Jingjiang River due to the impoundment of the Three Gorges Reservoir.
• Employed Copula function to study inflow characteristics over different periods.
• Developed a flow coupling relationship model based on fluvial motion laws.
• Conducted a quantitative analysis of backwater event probabilities and intensities before and after Three Gorges Reservoir impoundment.
• Increased probability of medium-low flow conditions merging with lake inflows by 44.6%.
• Probability of main flow merging with flood conditions increased by 5.4%.
• Reduction in average backwater intensity affecting the main river channel, with a shift towards extreme backwater events observed from April to July.