Quantifying the benefits of pervious asphalt pavement and bioretention facility in road LID strategies for urban drainage network optimization

As two representative LID measures for roads, pervious asphalt pavement and bioretention facilities provide effective urban stormwater control. Existing research remains limited regarding the stormwater control performance of these two materials at the urban catchment scale and their synergistic interactions with drainage systems. This study developed a pervious asphalt pavement system and a bioretention facility as two key road LID measures. The regional-scale synergistic effects of integrating these materials with drainage networks were evaluated in a high-rainfall urban environment (annual precipitation >1500 mm), employing pervious asphalt pavement for 50% transportation areas and bioretention facilities for public land. Laboratory-derived hydraulic parameters were incorporated into a calibrated Storm Water Management Model (SWMM) to simulate five rainfall return periods. Key findings include: (1) LID prevents drainage system overload, which otherwise occurs within 30~70 minutes under extreme rainfall. (2) For a 10-year rainfall event, LID reduced the required pipe diameter expansion by 60%. (3) Combined with existing infrastructure, LID maintained low flood risk up to a 5-year event, while a 40% pipe expansion eliminates flooding across all scenarios. (4) The hybrid strategy (LID + 40% pipe expansion) reduces retrofitting costs by 70~83% while achieving performance comparable to conventional systems.