Optimizing bio-pore infiltration systems for urban flood mitigation: A field study in Bandar Lampung, Indonesia

Urban expansion in Bandar Lampung, Indonesia, has exacerbated urban flooding due to increased impervious surfaces and reduced natural infiltration. Bio-pore infiltration systems are promoted as a low-cost, eco-friendly solution to enhance groundwater recharge and mitigate surface runoff. This study quantifies the effectiveness of 75 bio-pore infiltration holes installed along Seroja Street in the Way Halim Sub-watershed. Using field data on flood depth and bio-pore absorption rates, complemented by hydrological modeling, we assessed their impact. Before installation, flood depths during heavy rainfall (96.7 mm daily maximum) ranged from 25–40 cm. Post-installation, these depths decreased to 10–20 cm, representing a 40% reduction. However, our analysis reveals that based on a measured absorption capacity of 118 L/hour per bio-pore and a total impermeable area of 2640 m², approximately 737 units are required to fully manage peak rainfall runoff for the street—indicating a significant shortfall of 662 units. These findings underscore the critical need to align green infrastructure design with site-specific hydrological parameters. When appropriately scaled, bio-pore systems offer a cost-effective and sustainable urban flood mitigation strategy for tropical regions.