Field Observation and Numerical Modelling for Morphological Response in the Macro-tidal Beach

Abstract

This study investigated the sediment transport and bed level change in the macro-tidal beach using field observation and numerical modelling. The study area is Sinduri beach, located on the west coast of Korea, which developed a large scale multi-sand bar with a tidal range of 5 to 7 m. The multi-sand bar is destroyed in the high-wave conditions (winter) and developed in the low-wave conditions (summer), which have different characteristics from the wave-dominated beach. Therefore, this study measured the wave level, current, and bed level change using ADCP (Acoustic Doppler Current Profilers) and VRS-GSP (Virtual Reference Station Global Positioning Systems) to investigate the mechanism of the multi-sand bar formation. Then, this study simulated sediment transport and bed level change, coupled with the Delft3D-FLOW and Delft3D-WAVE model. The numerical results show that sediment transport and bed level change dominantly occurred under the shore-normal wave condition and tend to develop a multi-sand bar. However, the destruction of the multi-sand bar was not reproduced. Delft3D-FLOW model is based on the two-dimensional depth-averaged shallow water equation and it is not applicable to simulate the wave-induced current near the seabed. Also, the aeolian sediment transport by north-west wind can not involve in the numerical simulation.