Vol15 No.3: 485-494
【Title】Sediment control function of river notches
【Author】Chia-Hsing LIN; Cheng-Ju LIU; Shih-Hsun LIN; Chjeng-Lun SHIEH
【Addresses】Department of Hydraulic and Ocean Engineering, National Cheng Kung University, 70101 Tainan, Chinese Taipei
【Citation】Lin CH, Liu CJ, Lin SH, Shieh CL (2018) Sediment control function of river notches. Journal of Mountain Science 15(3). https://doi.org/10.1007/s11629-017-4546-1
【Abstract】The purpose of this study is to investigate the control function and mechanisms of natural river notches. Physical and numerical experiments are analyzed in this study for two representative types of sediment events: high intensity and short duration Type A sediment disaster events, and low intensity and long duration Type B moderate non-disaster events. Two dimensionless parameters, sediment trapping rate and reduction rate of peak sediment transport, are defined to evaluate the sediment control function of river notches. Study results indicate that the contraction ratio of the notch has a significant influence on sediment control function, with high contraction ratios resulting in both high sediment-trapping and high reduction rates. River notches provide better sediment control during Type A events than Type B events. The sediment control mechanism of river notches is the result of multiple interactions among river flow, sediment transport, and riverbed variation. Analysis of these interactions supports the significant protection role of river notches on sediment control for disaster events.
【Keywords】River notch;Sediment control function;Sediment control mechanism;Sediment trapping rate;Reduction rate of peak sediment transport