Abstract:

Jingjiang River is often seriously threatened by floods. Since the operation of the Three Gorges Project and the reservoir group in the upper reaches of the Changjiang River, the process of runoff from the reservoir has changed and sediment load has decreased sharply. Along with the channel erosion and river regime adjustment under the new water and sediment situation, the bank collapse danger of part of the bank protection engineering section in the Lower Jingjiang River has occurred from time to time. If no remedial measures are taken, the local river regime will further deteriorate, and has a greater impact on people's lives and property safety and economic and social development. Taking the sudden bank collapse and disposal of “Tianzi-1” section, a typical hazardous section in the Hunan province of Lower Jingjiang River in 2023 as an example, the characteristics of water and sediment changes and local river channel evolution were analyzed, the causes of bank collapse were investigated, and emergency risk control measures were carried out on the basis of fully considering the hydrodynamic and sediment dynamic. Based on the study, we proposed some suggestions on middle-long time river regulation, providing support for the prevention and control of bank collapse in the middle and lower reaches of the Changjiang River under the new water and sediment situation.

Key words: bank collapse, water and sediment regime, channel evolution, dangerous situation handling, lower Jingjiang River