Relations between Deposition of the Xiaolangdi Reservoir and Scour of the Lower Yellow River Channel

The paper shows the close relationship of sediment delivery ratio of the lower river channel in the downstream of the reservoir with the reservoir sediment delivery ratio and the almost single-valued function in theory.It establishes the relations between reservoir sediment delivery ratio and sediment delivery ratio of the lower river channel by using 20-year operational data of Sanmenxia Reservoir.It also uses 7-year initial operational data of the Xiaolangdi Reservoir for checking,showing conforming to reality.Thus,it provides sediment delivery ratio,scouring amount,sediment reduction rate and time of sediment reduction under the different conditions of incoming sediment and various kinds of deposition of the Xiaolangdi Reservoir.The relation of sediment delivery ratio of the lower river channel and reservoir sediment delivery ratio shows that the channel scour and sediment reduction all have maximum value,showing its deep mechanism.It is important for a regulated discharge regime of the river and can immediately make effective selection.