Heshangtan is a typical navigation-obstructing reef section in the river section from Fuling to Fengdu.On both sides of this section,reefs are distributed,the shoreline is extremely irregular,the water flow is rapid,the gradient is large,and the flow pattern is chaotic.Marine accidents occur frequently,which has become a bottleneck restricting the overall navigation efficiency and safety of the 4.5 m deepwater channel in the reservoir area.By analyzing the hydrological characteristics and navigation-obstructing features of the Heshangtan section,a regulation scheme for clearing the reefs at Heshangtan and Guojiazui is proposed,and a two-dimensional plane flow mathematical model is used to simulate and evaluate the effect after the implementation of the scheme.The results show that the reef clearance engineering effectively widened the river channel,improved the flow pattern in the navigation channel,significantly reduced the intensity of cross-flow and backflow,and improved the safety and efficiency of navigation.After the reef clearance,the width of the upstream navigation route in the Heshangtan section is widened from 35 to 75 m,and the self-propelled upstream flow rate is increased from 180 million to 304 million m3/s,and the navigation conditions in the section are significantly improved.The research results can provide reference for the channel regulation of similar complex river sections.