Longshore sediment transport in the swash zone at Desaru Beach

Abstract

This study examined the processes of longshore sediment transport in the swash zone at Desaru beach, Johor. It focused the suitability of sediment trap on sandy beach and beach profile’s survey to determine the direction of longshore transport. Field measurements were carried out by using sediment trap, Global Positioning System (GPS) kit and water level logger. Data collected are sediment samples, beach profile and tides. Laboratory sediment analysis also conducted to determine the size, density and porosity at the area. It was found that the sediment trap is unsuitable to be used at Desaru beach. This could be due to highly turbulent waves and sediment transport from the cross-shore direction that had fully covered the trap with sediment. The beach profile survey shows that the direction of the longshore transport is coming from northwest to southeast of the beach. From the analysis of sediment samples, it was found that the sediment size ranges from 0.33 mm to 0.35 mm with median diameter of 0.34 mm. From the experiment, the average porosity is approximately 0.43, whereas the average density is about 2635 kg/m3. As conclusions, the sediment trap is unsuitable to be used at sandy Desaru beach. The direction of the longshore transport is from northwest to southeast of the area during Northeast monsoon.