The water replenishment inlet of the Yangtze-to-Hanjiang River Diversion Project is located approximately 5 kilometers from Anle River outlet downstream of the Danjiangkou Dam, with the replenishment volume matching the diversion volume. The project’s impact on the waterway primarily manifests in the water reduction section. Comprehensive management is essential to restore navigable water levels during dry season. The effectiveness of the management plan was evaluated using a river engineering model, and the plan was optimized and further verified. Results indicate that, under the tailgate water levels of 86.47 meters and 85.90 meters for the 212 m³/s water reduction-replenishment plan, the water level from the diversion channel entrance to Huangjiagang decreases, while the water level downstream Huangjiagang remains unchanged. Notably, the water level at the diversion channel entrance experiences the largest drop, decreasing by 0.08 meters and 0.19 meters, respectively. After the comprehensive management plan 1 is implemented, the water level at the diversion channel entrance is reduced by 0.02 meters. However, the water level in the water-reduction section does not recover to pre-diversion levels, primarily because replenished water from the Anle River estuary fails to enter the left main waterway. Based on these experimental results, it is recommended to optimize the management plan by installing two bottom protection belts along the lower edge of the Canglangzhou outlet. Experiments identified four elevation values for these belts, with a recommendation to set the elevation at 85.5 meters. Further detailed analysis supports this elevation. The optimized plan is expected to slightly elevate the water level from the diversion channel entrance to Huangjiagang above pre-diversion levels, with a maximum increase of 0.06 meters at the channel entrance.