MOVABLE-BED EXPERIMENT ON BEACH CHANGES AROUND ARTIFICIAL REEF AND THEIR PREDICTION USING BG MODEL

Abstract

 On the Kaike coast an artificial reef with crests was constructed in place of one of 12 detached breakwaters. After the construction, the scale of a tombolo was reduced because of the generation of shoreward currents on the artificial reef, and severe scouring occurred at the opening between the artificial reef and existing detached breakwater owing to the development of rip currents. To improve this condition, the effect of raising the crown height of the artificial reef was investigated by a movable-bed experiment using a plane wave tank. The numerical simulation using the BG model, which takes the effect of not only waves but also strong nearshore currents into account, was applied to the results of the model experiment and the Kaike coast, by improving the evaluation of the depth of closure, while taking the effect of the current velocity into account. The predicted and measured beach changes around an artificial reef were in good agreement both in the experiment and in the field.