Function of Detached Breakwater to Control Longshore Sediment Transport

The function of offshore detached breakwater of controlling longshore current and resulting sediment transport under oblique wave incidence is examined mainly through experiments. Although the offshore detached breakwater can effectively reduce incident wave energy, it has little influence on longshore current. More than 50% of the volume of sediment transported in the longshore direction on the natural beach is trapped behind the breakwater. The total longshore sediment transport rate around the breakwater can be predicted more precisely by integrating the local longshore sediment transport rate estimated from the flux model than by the empirical formula of Savage type.