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Time variations of coastal bathymetry and sand grain size were investigated at the north Kashimanada Coast, a 40km long section of coast located between Oarai Port and Kashima Port, Japan. From the change of coastline position obtained from aerial photographs and bathymetrical surveys, it was found that the beaches located just next to Oarai Port and Kashima Port had been depositional and the areas next to those depositional beaches had been heavily eroded. Grain size distributions at the shoreline showed a tendency that grain size became coarser in the eroded areas and the areas were expanding. From analyses of the bathymetrical surveys, it was found that in almost 2/3 of the coast, offshore longshore sandbars diminished from 1984 to 2004, and it can be considered that the sediment movement caused by the headland system might be responsible for the extinction of the offshore sandbars.

This paper classifies bedforms surrounding a headland using side scan images and swath bathymetry. The study is part of a project investigating headland sand bypassing. The field area is the inner shelf, between 5 and 25 m depth, around Santinho's headland, located in northeast of Santa Catarina Island, southern Brazil. The data was collected with an Edgtech 4600^™ interferometric sonar, 540 KHz and covered an area of approximately 1 km². The classification is in accordance with the literature, and preliminary results show an occurrence of asymmetrical, catenary bedforms that ranges in length from 6 to 15 m and height from 0.5 to 1.2 m, along the southern section of the headland. These features are almost perpendicular to the shoreline and are indicative of bed load transport. Their asymmetrical shape indicates that a sand transport is occurring in a northerly direction and is associated with the headland sand bypassing.