Abstract
The Kako River flows through Hyogo Prefecture. The influence of runoff due to barrage water and the Mino River tributary, combined with a meander in the river upstream from the large barrage on the Kako River (Kakogawa Barrage), has promoted the development of a sand bar on the river bank opposite the confluence. The sand bar, which has hardened, currently deflects the passage of water back to the left bank and has decreased the usable water surface area of the river. The objective of this study was to survey the river topography in the vicinity of the Mino River confluence and identify the factors responsible for sand bar development. In addition, movable-bed modeling of the channels at the tributary junction was performed to assess the influence of the barrage water and the river meander upstream on river flow, and to consider the effect of the spur dike installed for control of a sandbar. The numerical calculations were analyzed using the two-dimensional flow analysis software, Nays2DH, to verify the experimental results and to investigate how they can be applied.
