Silting thickness analysis of regular desilting in rectangular and trapezoidal channel

Silting in river is a dynamic process, so it needs to regular desilting. At present, underwater siltation monitoring is still in its early days and based on experience. This paper puts forward the criterion of discrimination, in which the flood discharge section is decreased by 20%. It used the method of steady uniform flow in open rectangular and trapezoidal channel for calculation. The results show that reference values of dredging thickness in different section forms were determined. Siltation thicknesses of rectangular channel are linearly related to water depth. And the reduction rate of trapezoidal channel has a quadratic function relation with silting thicknesses. They were proportional to channel width and their rates trended to mitigation when the bottom width and flood depth were constant. In addition, the reference value of dredging thickness should be determined by combining with the bottom width, surface width, water depth and other actual situation.