河道に造成されたワンドの形状が土砂堆積に及ぼす影響

抄録

Wando have been artificially created in river channel because it sustain variety of aquatic species and form water landscape. However, it is difficult to keep ideal condition of Wando because river flow cause sedimentation of Wando. In this study, by referring documents, aerial photographs and field observation, we clarified the location, number, shape, origin, condition of Wando in target area. In addition, we monitored thickness of sedimentation in seven sites during two to seven months as well as measured the sediment size of bed material of Wando. As a result, we clarified Wando which has narrow opening toward downstream tend to be maintained against sedimentation by flood. In tidal area, fine sediment can be transported by tide and deposited in Wando. In such a situation, bed slope of Wando which is milder than 1/100 increase the sedimentation of fine material by tide. Considering these points, we proposed a shape of Wando which reduce sedimentation by flood and tide.