A Study On The Influence Mechanism Of Variation Of Water And Sediment On Channel Geometry Of Shashi Reach

After the impoundment of the Three Gorges Reservoir, the water and sand conditionof dam downstream reach has changed, and the downstream river channel will be scouredcomparably severely in a long time. This paper selects Shashi reach and deeply analyzesthe influence mechanism of riverbed morphology from aspect of section morphology,longitudinal river slope and sandy islet area etc due to variety of water and sand condition,then predicts the channel feature variation tendency of Shashi reach.The main contents of the paper are as follows:(1) The influence mechanism of riverbed morphology from section morphology due tovariety of water and sand condition is reviewed. This paper extends to riverbed morphologyfrom aspect of longitudinal river slope and sandy islet area etc, then analyzes the influence.(2)Water and sediment features of Shashi Hydrometric, Zhicheng Hydrometric andthree outlets of Jinjiang River are analyzed. And annual runoff of Shashi has beenforecasted using wavelet analysis.(3)Evolvement law of Shashi beach is concluded from general rules of fluvialprocesses, then the impact factors are analyzed.(4)The physical model design and test of Shashi reach is analyzed, whose accuracyrating is compared and also analyzed.(5)Correlation analysis is performed according to channel morphology and water andsediment factors. The polynomial is established by using partial least squares. Mechanismresearch of water and sediment load variation influencing on transversal profile is studied.(6)This paper forecasts the change of river regime of Shashi beach, whose rationalityis explained. The problem of Shashi reach is given suggestion.