TOPOGRAPHIC CHANGES OF AJIGAURA BEACH CAUSED BY WAVE SHELTERING EFFECT OF OFFSHORE BREAKWATER

Abstract

 Topographic changes of Ajigaura Beach caused by the wave sheltering effect due to the offshore breakwater of Hitach-naka Port were investigated. Aerial photograph was taken on November 5, 2010 using an unmanned aerial vehicle. Shoreline changes were investigated using seven sets of aerial photographs taken between 1984 and 2010, including the photograph taken on November 5. In addition bathymetric survey data taken in 1996 1999 and 2002 were compared. Finally it was concluded that the beach changes at Ajigaura Beach was triggered northward longshore sand transport, which was caused by the wave sheltering effect of the offshore breakwater.