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.

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.

The general situation of Jinghong waterway is introduced,and the cumulated rate of sand transport and the dominant discharge for channel formation are calculated,and the causes of the formation of Jinghong shallow as well as it s evolution trend are analyzed,and the regulation principles for relevant readers are put forword.

Wannianzhou Shallow is one of the four important shallows between Heyuan to Huizhou reaches of Dongjiang River, the characteristics of hydrology, sediment and riverbed variation of which are influenced by multiple factors such as navigation, water intake and flood control, etc.

In this paper,based on the model testing of stabe bed and mobile bed,the best scheme to improve the navigation condition of the shallow is presented.