Abstract: Siltation around high-pile wharves poses a serious threat to their structural integrity and operational safety. This study investigates tidal hydrodynamic characteristics and sediment transport patterns behind high-pile wharves through field observations and large-scale physical model experiments, providing field-supported evidence of groynes' potential to reduce sediment deposition behind the high-pile wharves. The results indicate that enhanced turbulence induced by both pile groups and sloping topography inhibits sediment deposition, while flow reduction caused by piles promotes it, with these counteracting effects jointly dominating sediment transport dynamics around the wharves. During initial tidal stages, cross-shore currents exclusively dominate sediment delivery behind the wharves. In mid-to-late stages, topography-induced alongshore currents and secondary flows regulate spatial-temporal sediment redistribution. Additionally, during the beginning and end of the tidal cycle, the extremely shallow water stage, characterized by steep velocity gradients and high shear stress, plays a significant role in driving bed changes. Physical model experiments and field data demonstrate that groynes enhance lateral flow and turbulence, thereby significantly reducing siltation behind the wharves. This study contributes to a comprehensive understanding of sediment dynamics around high-pile wharves and proposes an environmentally friendly strategy for reducing sediment deposition.