Abstract
Formative process of asymmetric river mouth bar was investigated through the case study of the Abe River mouth flowing into Suruga Bay. Aerial photographs and bottom sounding data were analyzed. It was found that the location of the opening of asymmetric river mouth is mainly determined by the location of the main river stream, but the straight shoreline of the river mouth bar and its height strongly relate to the incident waves. Breaker height and breaker angle around a river mouth ar were inversely calculated from the longshore sand transport formula and they well explained the sediment tranbsport mechanism around the protruding river mouth.