極浅海域に形成されたbarrier island の観察と数値計算結果との比較

抄録

In Nabeshima area in Nakatsu tidal flat facing the Suo-nada Sea, a slender sand bar has extended in extremely shallow sea in recent years, and connected to the other shore, resulting in the formation of a barrier island. The planform changes in the sand bar in Nabeshima area were investigated using aerial photographs taken between 1981 and 2010, and the deformation process was studied. Observed results were compared with the results of the numerical simulation regarding the formation of a barrier island on a sloping bed with a 1/40 slope, which was carried out by Serizawa and Uda (2013) using the BG model (a three-dimensional model for predicting beach changes based on Bagnold’s concept). The observed change in a barrier island in Nabeshima area and the calculated results were in good agreement in terms of the change in planview of the barrier. A mound was constructed as a headland using the dredged materials containing gravel in this area before 1981, and this artificial mound effected as a supply source of sediment for the development of a barrier.