FIELD INVESTIGATION OF BEACH CHANGES ALONG MERGINAL SHORELINE OF BANZU TIDAL FLAT

Abstract

 The shoreline changes in the merginal area of the Banzu tidal flat were investigated by using aerial photographs and field investigations. The area immediately north of the Obitsu River mouth was eroded due to the spatial imbalance of longshore sand transport, and sand was transported to form a sand spit at the mouth of the north tributatry of the Obitsu River. The longshore sand transport rate was estimated to be 127 m³/yr at the site. Furthermore, the barrier top was moved landward by 7 m on average owing to the overflow of the 2011 Great Tsunami.