Short-term variations and influencing factors of suspended sediment concentrations at the Heisha Beach, Guangdong, China

Knowledge of sediment variation processes is essential to understand the evolution mechanism of beach morphology changes. Thus, a field measurement was conducted at the Heisha Beach, located on the west coast of the Zhujiang River (Pearl River) Estuary, to investigate the short-term variation in suspended sediment concentrations (SSCs) and the relationship between the SSC and turbulent kinetic energy, bottom shear stress (BSS), and relative wave height. Based on extreme event analysis results, extreme events have a greater influence on turbulent kinetic energy than SSC. Although a portion of the turbulent kinetic energy dissipates directly into the water column, it plays an important role in suspended sediment motion. Most of the time, the wave-current interaction is strong enough to drive sediment incipience and resuspension. When combined, the wave-current interaction and wave-induced BSSs have a greater influence on suspended sediment transport and SSC variation than current-induced BSS alone. The relative wave height also has a strong correlation with SSC, indicating that the combined effect of water depth and wave height significantly impacts SSC variation. Water depth is mainly controlled by the tide on the beaches; thus, the effects of tides and waves should be conjunctively considered when analyzing the factors influencing SSC.