306 / 2024-02-29 12:51:42

Temporal and spatial variations of bank collapse in the middle reaches of the Yangtze River after the Three Gorges Project operation and its impact on channel adjustment

bank erosion,channel adjustment,water and sediment variation,middle reaches of the Yangtze River,Three Gorges Project

Under the effects of the Three Gorges Project and upstream cascade reservoirs , the river channel in the middle reaches of the Yangtze River had experienced marked scouring and locally sharp adjustment. Therefore, it leaded to a significant increase in the probability of shoal and bank erosion, which had an important impact on the stability of river regime, flood control safety, smooth navigation, and normal operation of water-related projects along the Yangtze River. Based on basic data such as bank collapse inspection, long-term field measurement, and semi-river topography, this study statistically analyzed the temporal and spatial characteristics of bank collapse in the middle reaches of the Yangtze River after the construction of the Three Gorges Reservoir. We also revealed the distributions of the frequency and intensity of bank erosion in typical hydrological years. It was found that after the Three Gorges Reservoir operation, the intensity and frequency of bank collapse in the middle reaches of the Yangtze River showed an increasing trend, with the intensity on the left bank generally greater than that on the right bank. In recent years, there have been an increasing number of sudden bank collapse, and the proportion of bank collapse in the protected bank sections has increased. On this basis, typical river sections with varied river types in the middle reaches of the Yangtze River were selected to explore the impact of bank collapse on river morphology adjustment. This study can provide scientific support for the systematic governance and water safety guarantee capacity in the middle reaches of the Yangtze River.