2019 Volume 75 Issue 2 Pages I_605-I_610
Futtsu cuspate foreland, which separates Tokyo Bay and Uraga Strait and extends westward, connected to Dai-ichi-kaiho Island in 1982. However, beach has been eroded in recent years, resulting in large shoreline recession. In this study, field observations were carried out at the tip of this cuspate foreland on July 16, 2017 and November 23, 2018 to investigate the present conditions of the foreland, as well as the shoreline change analysis using past aerial photographs. When the volume change of the beach was calculated from the change in the foreshore area between 2004 and 2018, and was multiplied by the characteristic height of beach changes of 3.1 m, eastward longshore sand transport on the north coast of the cuspate foreland was evaluated to be 1,160 m3/yr, assuming that sand supply from the south side was entirely disrupted. Sandy beach has been disappearing owing to the imbalance in longshore sand transport at Futtsu cuspate foreland.
