Prediction of Topography of Stable Beach Produced by Gravel Nourishment at Jinkoji Coast and Further Nourishment using Medium Sand

Abstract

On the Jinkoji coast facing the Pacific Ocean, beach nourishment using 8.7×104m3 of gravel with grain sizes ranging from 3 to 15 mm had been carried out by April 2008. After beach nourishment, a stable beach was formed between the artificial headlands. In response to the success in recovering a sandy beach, beach nourishment was also planned for the Komiyasaku coast south of the Jinkoji coast along with the Oritsu coast, which is a famous recreational beach. In this case, beach nourishment using gravel is considered to have been avoided for recreational use. Taking these conditions into account, beach nourishment using medium sand was planned. A stable beach topography produced by gravel nourishment was reproduced numerically using the BG model, while incorporating the effect of changing the grain size into the model, and the effectiveness of the model was confirmed. Then the model was applied to gravel nourishment along the Komiyasaku coast and to beach nourishment using medium sand at the Oritsu coast.