Author(s): Naohiko Sassa; Akihiro Tominaga; Yuji Hara; Yuka Kuno
Linked Author(s): Akihiro Tominaga
Keywords: Local scouring; ADCP; 3D flow structure; 3D numerical simulation; Kiso River
Abstract: In the Kiso River, the sand layer was locally and severely scoured by peeling of the clay layer which covered sand layer. This local scouring that begins with a detachment of the clay layer has been reported in other alluvial rivers. In order to propose river management measures of preventing similar local scours, it is important to understand the cause of such scours. In this study, based on the occurrence process of local scour in the Kiso River, we conducted numerical simulations of three-dimensional bed deformation under the condition that characterize the local scouring; an existence of boundary between semi-fixed clay layer and loose sand layer, and a formation of backward-facing step caused by the bed degradation downstream from the boundary. Then, the influence of these conditions on the occurrence and progress of local scouring was investigated.
Year: 2018