Laboratory Study of Surf-Zone Turbulence on a Barred Beach

Wave height, wave set-up, undertow, and turbulent velocity on a plane beach and a barred beach were compared in the case of regular waves. The study showed that the presence of an offshore bar altered the turbulent flow in the surf zone by altering the characteristics of the broken waves. It was found that the magnitude of undertow and turbulence intensity were smaller in the inner surf zone on the barred beach. These results suggest that it may be possible to reduce the erosive wave action on beaches by construction of underwater berms in the nearshore zone. Further studies are needed to determine the effects of water depth, berm width and crest elevation on surf-zone turbulence under different wave conditions in order to provide explicit design guidance.