Field Observation of Suspended Solids and Bed Materials at Cut-off Chanel in Honmyo River

It was necessary for the appropriate river management to grasp the spatial variation of river bed form. In 2008, Honmyo river was extended as the completion of Isahaya Bay reclamation project. Recently, ascent of river bed can be observed in this extended section. In this study, regarding that the concentration of suspended matters is high and their settlement to the bed can be one of factors to cause the variation of river bed form, field observations on suspended solids (SS) were carried out. And soil tests were done for the bed materials. From the obtained results, there are relationship between SS and turbidity with high correlation value. Concentrations of SS and turbidity is low at the upstream and is becoming high around the midstream and downstream. The flow at the bottom layer affects the temporal changes of SS. The riverbed is covered with the fine particles classified by clay or silt. Regarding that the moisture content of riverbed is high, bed material can be picked up into flowing water