Scientific Development Research

This study focuses on typical river sections in tidal-influenced areas. By combining hydrodynamic simulation with acoustic monitoring, it analyzes the variation characteristics of flow velocity, flow direction, and turbidity under different demolition timings, and assesses the degree of disturbance to fish migration behavior. The results show that phased, step-by-step demolition of the cofferdam in the direction of the water flow can effectively reduce the duration of high-turbidity zones and lower the probability of fish perception barriers and channel blockages. In contrast, one-time overall demolition causes significant hydrological disturbances in a short period, increasing the risk of migration delays. This study provides data support and management recommendations for the ecological optimization of hydraulic engineering demolition in tidal-influenced areas, helping to balance the ecological needs of aquatic organisms while ensuring project progress.

Tidal-influenced area; Cofferdam demolition; Fish migration; Hydrodynamic disturbance; Ecological protection