• • Under pumping at 1000 m³/h, maximum groundwater drawdown reaches 1.24 m during dry season, indicating that gallery operation significantly lowers water levels, which is critical for managing aquifer sustainability and avoiding over-extraction.
• • Near-field monitoring wells respond 2–3 days faster to pumping than far-field wells, demonstrating that hydraulic response time is spatially heterogeneous; this lag must be accounted for in real-time monitoring and operational control systems.
• • Pumping enhances groundwater-gallery water exchange by approximately 4 times compared to natural conditions, with the effect more pronounced in dry season; this quantifies the gallery's role as an active hydraulic boundary that can be managed to optimize water yield.
• • Water exchange is concentrated near transverse and longitudinal gallery sections, aligning with the perforated structure's localized permeability enhancement; this spatial pattern informs optimal placement of monitoring and maintenance efforts.