Scour formation behind submerged breakwaters is seen in two coasts with different characteristics, which shows the relation between scour formation and submerged breakwaters. In this study, mechanism of the scour formation has been examined by comparing the characteristics of the two coasts. Some evidence of the relation between the scour formation and turbulence behind submerged breakwaters were found and simultaneous observation of current, turbidity, and seabed change were carried out in the area behind the submerged breakwater. The observation results indicate that the turbulence due to wave breaking on the submerged breakwaters and offshore mean current strongly affect the sand transport behind the submerged breakwaters.
