Development of a Filtration System to Enhance Drainage Discharge Capacity

Climate change-driven increases in extreme rainfall disrupt the urban hydrological cycle in highly impervious settings and overload drainage systems, thereby intensifying flooding. Low Impact Development is therefore increasingly being adopted; among its measures, permeable pavements installed on parking lots and roadways can facilitate stormwater storage, infiltration, and delayed discharge. However, hydrological evaluations of permeable pavements integrated with drainage infrastructure remain limited. This study experimentally compares two systems under successive high-intensity storms: Pavement A, a permeable pavement over an impermeable subgrade with no subbase-to-catch-basin drainage, and Pavement B, a permeable pavement with a subbase that provides lateral drainage to a catch basin. Compared with Pavement A, Pavement B achieved greater event-scale runoff reduction and peak-flow attenuation and, after rainfall ceased, sustained long-duration delayed discharge that promoted pore-space recovery and more stable drainage performance. These findings indicate that the integration of permeable pavement with catchment and basin systems offers both short-term (runoff and peak mitigation) and long-term hydrological benefits, supporting its application in improving urban water-cycle resilience.