Uno, K. and Nakano, S., 2007. Effect of Tidal Current on Sediment Transport at the Tidal Flats. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 746 – 750. Gold Coast, Australia, ISSN 0749.0208

To study the sediment transport at the tidal flat and the bar of the river mouth, it is useful to clarify the mechanism of colonization of vegetation or the settlement of benthic animals. This paper focuses specifically on the transport of the sediment to which the diameter is 2,000 µm or less, according to tidal current. The study site is located at the mouth of the Yoshino River, Shikoku Island, Japan. In this study, field observations were carried out to measure the sediment accumulation in a period between two successive low tides. Secondly, time variation of friction velocity on a tidal flat with uniform slope was calculated to examine the relationship between the sediment transport and tide level. Thirdly, 2-D FEM tidal current simulations were conducted to clarify time series behaviour of friction velocity on the tidal flat and the river mouth bar. Finally, the amount of sediment transportation was estimated. This resulted in: 1) The results of field observation coincide approximately with that of theoretical analysis using a tidal flat with uniform slope; 2) The value of friction velocity becomes greater just before dry up and just after submerged; and 3) The amount of sediment transport was generally estimated by bed load theory.