On the Hamamatsu-goto coast located west of the Tenryu River mouth, beach has been eroded severely in recent years, resulting in the exposure of the seawall protecting the sewage facility. Now urgent measures are required to prevent the damage to the seawall. In particular, large-scale offshore troughs have developed in this area, resulting in strong wave action to the seawall. Erosion around the Tenryu River mouth was investigated using aerial photographs, NMB and bottom sounding data along with the grain size analysis of seabed materials.
