Siltation Factors Identification of the Main-Channel of Gaocun-Lijin Reaches in the Yellow River

The main-channel of the lower Yellow River is its main path to transport floods and sediment.Since 1986,the main-channel has been shrinking step by step.Based on the observed data and river sediment dynamics theory,the paper concluded that almost all the deposition in the main-channel from Gaocun to Lijin was produced in non-flood season.Large volume of water for irrigation,unharmonious geometry pattern and the hyper-concentrated-sediment flood were the main factors influencing the main-channel,and the drying-up in later 90's increased the deposition ratio of the Gaocun-Aishan reaches.In order to decrease the deposition,the factors such as the discharge and sediment concentration and etc.should be controlled reasonably.Moreover,the paper also suggested that the Xiaolangdi reservoir should increase its sediment delivery ratio to stop the continuing scouring on the lower Yellow River.