To address the navigation channel deterioration in Jiangxinzhou-Wuhe reach of the lower Yangtze River prior to the phase II regulation project,manifested as narrowing of the navigation channel in the Jiangxinzhou central bar transition section,decreased flow diversion ratio accompanied by deep channel siltation in the Xiaohuangzhou transition section,continuous narrowing of the channel width,and reduced bend radius,a waterway regulation project was implemented to enhance the channel dimensions and curb the adverse developmental trend from 2019 to 2022.Based on hydrological observations and topographic survey data,this study quantitatively analyzed the effectiveness of the phase II regulation project by systematically comparing hydrodynamic conditions,riverbed morphological evolution characteristics,and navigation parameters before and after the project implementation.The results indicate that the project effectively protected key bars,contributing to the stabilization of the bar-channel pattern;successfully curbed the unfavorable trend of the main flow shifting to the right in the central bar transition section and the decreasing flow diversion ratio in the left branch of the central bar and the Xiaohuangzhou transition section;and significantly improved navigation conditions,with the channel dimensions stably achieving the design targets.The research findings provide a scientific basis for evaluating the effectiveness of waterway regulation in complex anabranched river reaches.