Assessing the feasibility of pervious concrete blocks for urban flood mitigation in bangkok using hydrological modeling

Abstract

Bangkok faces escalating flood risks due to rapid urbanization, high surface imperviousness, and intensifying storm events. Conventional drainage systems, limited by spatial and financial constraints, are increasingly unable to manage peak runoff. This study investigates the feasibility of using pervious concrete blocks referred to hereafter as pervious blocks as a green infrastructure retrofit for flood-prone zones in Bangkok. A PCSWMM-based hydrological model was calibrated and validated using 2023 rainfall events. Two scenarios were simulated across twenty-two high-risk zones: baseline (existing conditions) and mitigation (with pervious block implementation). The results showed that pervious blocks reduced peak runoff by 21.80 %, delayed time-to-peak by 20–30 min, and shortened flood duration by 35 %. Central Bangkok, with its high impervious surface coverage, experienced the greatest benefit. The findings support the integration of pervious blocks into sidewalks, pedestrian corridors, and low-traffic areas as a decentralized, space-efficient measure. This approach offers a practical solution to relieve pressure on drainage systems and improve urban flood resilience. The study provides operational insights for Bangkok’s flood adaptation strategies and offers transferable implications for other tropical megacities. Long-term maintenance and integration with urban planning policies are recommended to ensure sustained performance and scalability.