Author(s): Yuki Morikawa; Yasunori Muto; Takao Tamura
Linked Author(s): Yasunori Muto
Keywords: Low-water revetment; Experimental flume; High-water bed; Mixed sand; Attacked surface
Abstract: The low-water revetment as one of flood control measures has been set from 1960s in many Japanese rivers. However the revetments cause both ecological and flood control problems. Therefore we have to examine how the arrangement of the revetments will impact on the river geometry. In our past study, we found out in Yoshino River degrading the riverbeds and migrating thalweg around revetments on the attacked surfaces, especially near thalweg. In this paper, we verified the response of channel bed to the arrangement of low-water revetments experimentally. All experiments were conducted in a laboratory flume of 83.5 cm in width, 12.0 m in length and 1/200-tilting bed slope at Hydraulics and Hydrology Laboratory, Tokushima University. We spread a mixed portion of 3 types of silica sand on the whole surface of channel bed. Furthermore, the high-water bed which is made from clay and decomposed granite soil was set on the right hand side of the channel. We expect to clarify how the revetments such as their lengths and locations effect to the downstream of attacked surfaces positions. When setting the revetments along the sand bar the bed erosion occurr along the revetments. When setting along the high-water bank, in addition to similar bed erosion along the revetments, the most upstream side of the revetments was severely eroded.
Year: 2018