Truong, T.K. and Tanaka, H., 2007. Effects of a river mouth terrace to longshore sediment transport. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 874 – 878. Gold Coast, Australia, ISSN 0749.0208

Recently, beach erosion has become a concern in Japan. Much research has studied the balance of sediment transport and influencing factors, but the influence of river mouths has rarely been of concern. For a coast including an estuary, river mouths can be seen as a source of sediment supply. However, for the case where a consolidated river mouth terrace exists, the longshore sediment transport can be intercepted, as well as the effect of jetty. Therefore, the existence of a river mouth terrace is not only the source of sediment but also intercepts the longshore sediment transport. To estimate these problems, a wide data of the river mouth and surrounding coast was used. The study area includes the Nanakita River mouth, located in the northern part of the Sendai coast, northeast Japan. Aerial photographs, taken every two months from 1990 to 2005, were used to analyze the shoreline changes and the effect of the Nanakita river mouth on longshore sediment transport. The results show that after 1998, the Nanakita river mouth terrace had no further effect of blocking the longshore sediment transport.