Research on the Influence of Siltation Height of Check Dams the on Discharge Coefficient of Broad-Crested Weirs

With the continuous operation of check dams, silting elevation whole dam gradually increases. When height is close to broad-crested weir, it will result in a large change hydraulic characteristics original flow pattern. For subsequent reinforcement work, necessary know how excessive sediment deposition affects overflow from weir into spillway. However, few studies about discharge coefficients are available case spillways with sediment. In this paper, and coefficient whose width 270 mm investigated physical experiments under different siltation heights discharges. The research shows that: (1) increase height, water level on decreases drop becomes smaller. overall pattern tends open-channel (2) same condition, surface profile along rises discharge, velocity front increases discharge. increases, which reflects that improves capacity weir. (3) present empirical formulas for have errors when there accumulation. Therefore, new formula obtained using experimental data its maximum relative error 4.02%, can provide theoretical basis risk elimination work dams Loess Plateau.