Abstract: Due to inherent limitations such as extended length,shallow water depth,and narrow boundaries,the internal flow conditions within narrow approach channels are sensitive to boundary disturbances.When subjected to inflow waves generated by large-scale lock operations,these channels experience complex,unsteady,long-wave motion that cannot be rapidly or sufficiently diffused,leading to hazardous navigational conditions.Hence,this paper extends the existing lock chambers at a major hydrological hub to accommodate vessels with capacities of up to 10 000 tons and increased throughput.The upgraded lock chambers will be arranged in parallel configurations,sharing the upstream and downstream approach channels.A single lock chamber in this configuration can reach a peak inflow rate of 748m³/s,approximately 65% more than the existing ones.Additionally,the upstream approach channel has a length of 1 200m,a bottom width of 140m,and a minimum water depth of 7m.The large volume of water intake for each lock operation induces intense,unsteady flows that cannot be adequately diffused within the limited confines of the channel.With a reservoir level of 145m and a single lock chamber in operation,the maximum wave height within the approach channel can reach 1.55m,posing a severe threat to navigational safety.Through several simulations optimizing the water intake location,we concluded that creating an intake zone between the channel’s inlet and its closed end could effectively counteract water flows.This strategy reduces the initial kinetic energy of the waves and improves wave height conditions in the approach channel.Based on this,relocating the intake from the front edge of the first lock to the open boundary of the approach channel led to a reduction in the maximum wave height to 0.73m and the maximum flow speed to 0.54m/s,achieving a 53% reduction in both measures.