Study on the Vertical Distribution of SS in an Estuary of Honmyo River

The Honmyo River which is the smallest A class river in Japan flows into the Isahaya Bay through Isahaya city in Nagasaki prefecture. Some observations held so far denote that values of Suspended Solids (SS) become large in an estuary. The river bed around its region is composed of extremely fine particles, and it is considered that both the resuspension and the deposition of particles have been occurred due to the tidal change. These phenomena affect the formation of cross section of river and also the prosperity and decline of tidal flat. Therefore, in order to investigate the vertical distribution of SS, field observations were carried out twice in the last fiscal year around the downstream reach of the Honmyo River. According to the observation, it becomes apparent that SS changes in complexity by resuspention, deposition, and other phenomena. Furthermore, through an investigation of the vertical distribution of SS, sizes of particles are strongly related to the tidal change. Finally, it is shown that detailed field observation will be expected for the precise estimation of the behaviors of SS