Responses Of Longitudinal Profile And Cross Sections To Variations Of Incoming Runoff And Sediment Load In The Lower Yellow River

Based on the fundamental of River Dynamics and Fluvial Processes, this thesis analyses the characteristics of the variations of the incoming runoff and sediment load, longitudinal profile, and cross sections in the Lower Yellow River; this thesis also studies the responses of longitudinal profile and cross sections to variations of incoming runoff and sediment load. Following four main points have been acquired:(I) Based on the characteristics of the variations of the incoming runoff and sediment load in the Lower Yellow River, and by regression analysis, there are good two times parabola relationships not only between the yearly variation of theincoming runoff and sediment load (W'_s=k₁W^'2+k₂W'+k₃) but also between theyearly difference of them (â–³W_s =k₁â–³W²+k₂â–³W+k₃).(II) The erosion and deposition have closed relationship with the yearly variation of the incoming runoff and sediment load in the lower Yellow River. Based on the characteristics of the incoming runoff and sediment load, longitudinal profile, and cross sections between 1961 and 1999 in the Lower Yellow River, this thesis analyses the characteristics of the erosion and deposition of every period in the Lower Yellow River, including quantity, intensity, the profile distributing, etc. The yearly erosion and deposition have good relationships with not only the yearly variation but also the yearly difference of the incoming runoff, the average sediment concentration, the incoming sediment coefficient. This thesis also finds that the wider channel in the upper river in the Lower Yellow River has the influence on the erosion and deposition in the lower part with narrow channel because of changing the incoming runoff and sediment load in the lower river.(III) From the macroscopical point and by the regression analysis, every yearly profile shows good four times parabola relationship. By analyzing the changes of the water level of the 3000m³/s and 1000m³/s between 1961 and 1999 along the river and calculating the river slope, this thesis finds the changing characteristics of the profile of every period, including the position of the erosion and deposition, quantity, and the...