Experimental Study on the Impact of Seabed Erodibility on Sediment Transport in Pearl River Estuary

The erodibility of sediment is a crucial parameter in water-sediment numerical models, directly impacting the accuracy of them. To study the influence of seabed erodibility on sediment transport in estuarine areas, a three-dimensional water-sediment mathematical model ECOMSED was adopted, incorporating a sediment consolidation mode. The sediment transport processes in the Pearl River Estuary was well simulated, mostly focused on the Lingdingyang area, with different critical erosion shear stresses conditions. The results indicate that the critical erosion stress is a crucial factor influencing sediment transport in estuarine areas, significantly affecting the distribution of suspended sediment in water and the erosion and deposition of the seabed. As the critical shear stress decreases, the suspended sediment concentration in the originally high-turbidity areas increases markedly, with an expanded scope and a tendency to spread downstream. When sediment consolidation is overlooked, the suspended sediment concentration rises, and its scope expands downstream and to the east. When the critical erosion stress is half of the baseline value, there is little change in the proportion of sediment entering the South China Sea. However, when the critical erosion stress is one-eighth of the baseline value, there is a noticeable increase in the proportion of sediment entering the South China Sea, suggesting that the critical erosion stress of sediment also influences the exchange of sediment between the estuary and the open sea. This study reveals the impact of seabed sediment erodibility on sediment movement and provides a theoretical reference for the setting of bed sediment parameters in water-sediment mathematical models.