Abstract
The contour-line change model considering change in grain size was used to reproduce the beach changes until 2015 on the Shizuoka-Shimizu coast. In the calculation, the effects that the grain size of the beach nourishment material prepared from the Abe River bed was excessively coarser than that naturally supplied from the river mouth, and the detached breakwaters offshore of Zo-Hebizuka area blocked longshore sand movement were taken into account. In order to recover sandy beach rapidly, it was concluded that sand bypassing at a rate of 8×104 m3/yr from the Abe Riber to the coast, sand back pass from the Miho runway to the Shimizu coast at a rate of 5×104 m3/yr are required together with the increase in sand volume from 3×104 m3/yr to 5×104 m3/yr instead of the beach nourishment of 2×104 m3/yr at Zo-Hebizuka area.
