［Purposes ］ This paper aims to fully understand the impact of aquaculture water intake and drainage channels on the hydrodynamics and sediment erosion/deposition in the bay，thereby providing a scientific basis for its sustainable development.［Methods］ This study established a 2D tidal current -sediment numerical model for Dingzi Bay usin g MIKE 21 software.Following rigorous validation，a comparative analysis was conducted to investigate the erosion/deposition evolution mechanisms in the bay ’s navigation channels under two operational scenarios：with and without aquaculture water intake and drainage channels.［Findings］ Dingzi Bay exhibits an overall geomorphological pattern of navigation channel erosion flanked by shoal deposition.The operation of aquaculture water intake and drainage channels has intensified erosional processes in the main channel and estuary mouth，with the annual maximum scour depth increasing by approximately 0.08 m.Concurrently，sediment accumulation on adjacent shoals has been amplified.The annual maximum siltation thickness increases by approximately 0.06 m.Due to the opening of aquaculture water intake and drainage channels，significant scouring has occurred at the mouths of these channels，such as near the lagoon outlet of Ludao Island and on both sides of Magu Island，with a maximum scouring depth of approximately 1.02 m.［Conclusions ］ Aquaculture water intake and drainage channels exert a notable influence on sediment erosion/deposition processes and hydrodynamic regimes within Dingzi Bay.In the presence of such channels，the flow velocities in Dingzi Bay ’s navigation channels experience a substantial increase.There are also marked alterations in the suspended sediment concentration across cross -sections and in the patterns of sediment erosion/deposition in the area.Therefore，when conducting numerical simulations of hydrodynamic sediment transport in bays，it is essential to retain the aquaculture water intake and drainage channels as much as possible.If simplification is necessary，the impact of these channels on the hydrodynamic sediment dynamics in the bay should be analyzed first.