Effect of a River Notch on Sediment Transport After a Severe Sediment Hazards

• Main Authors: Chia-HsingLin, 林家興
• Other Authors: Chjeng-Lun Shieh
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/xu3q3c

博士 === 國立成功大學 === 水利及海洋工程學系 === 106 === The purpose of this study is to investigate the sediment control function and mechanism 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. All 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.