Through comparatively integrated prototype measured data, analysed the water sand condition and variation character of Bantan beach located in the backwater effect region of reservoir head after completion of the Xijin hydropower station on Yujiang, the cause of beach formation of Bantan and its principle of regulation were explored also.

The middle and lower reaches of the Yangtze River is typical bending braided river which have many shoals and the riverbed evolution of these reaches is serious.

Evolution characteristics of the shoals of the second and third generation alluvial islands in the Changjiang Estuary;

The exposed and unexposed shoals and their bearings on the carbonate reservoirs in the Feixianguan Formation in the northeastern part of the Sichuan Basin;

Combining with the moving characteristic of water and sediment,mechanism of shoal s navigation-obstru.