On the Shizuoka and Shimizu coasts in Suruga Bay, many detached breakwaters have been constructed as a measure against beach erosion, originally triggered by the excessive riverbed mining in the Abe River. After the construction of the detached breakwaters, a sand accumulation zone has propagated downcoast from the river mouth with a propagation velocity of 260 m/yr as a sand body. Bathymetric surveys have been carried out yearly to monitor the movement of the sand body, and it was confirmed that the sand body is still evolving. In this study, bathymetric survey data were first analyzed, and the movement of the sand body was quantitatively predicted using the contour-linechange model. Furthermore, a method accelerating the movement of the sand body was investigated. The best way is to carry out beach nourishment with a rate of 2×104m3/yr at a location 1.0km downcoast of the tip of the present sand body.
