FLUVIAL PROCESSES NEAR THE WENCUNJIA SAND BAR ON THE UPPER JINGJIANG RIVER

摘要

In May 2002, major bank failures occurred on the floodplain along the Wencunjia section, located near the Jingjiang River levees downstream of the Three Gorges Reservoir. The total length of collapsed floodplain was about 550m with a maximum collapsed width of 10m. The distance between the collapse location of the floodplain and the foot of the Jingjiang levee was a mere 44m. The floodplain failure has drew serious concern. Based on observed data, basic dynamics of fluvial processes, and the past evolution of the Tuqizhou chute, this paper presents an analysis on the changes of the thalweg, the cross sections of Tuqizhou chute in recent years, and the fluvial process of the Wencunjia reach. The results indicates that the main reason of bank falure was that flow in the main channel scoured the bank after 1999 because of the main channel migrated to the north in this reach.