Work

Integrating hydrodynamic modelling and nature-based solutions for urban flood resilience: a retrofitting framework in the vicinity of George Town UNESCO World Heritage Site

Year: 2026

Type: article

Abstract: Urban flooding is intensifying in high-density tropical cities due to climate change, rapid urbanisation, and limited drainage capacity. While nature-based solutions (NbS) are widely recognised for urban flood mitigation, their application in dense urban environments remains spatially limited and lack of integrated methodologies. This study aims to identify flood trends in the vicinity of George Town UNESCO World Heritage Site using multi-return period (ARI) hydrodynamic modelling. We developed a flood-based NbS retrofitting intervention through bioswale and retention storage within an existing urban football field and incorporated community-led participatory approaches in flood risk management. Hydrodynamic simulations across multiple ARI scenarios (2-100 years) reveal increasing flood extent and depth under higher rainfall intensities, identifying critical flood-prone zones. A decentralised NbS system was designed, providing approximately 5,000 m3 of combined surface and subsurface storage. Results indicate complete mitigation of surface flooding under the 100-year ARI scenario, with peak-flow reductions ranging from 11% to 23%. Community engagement further informed the design, ensuring usability, accessibility and long-term acceptance. The study demonstrates integrating hydrodynamic modelling, flood-based NbS retrofitting space-efficient strategy and participatory planning enhances both technical performance and implementation feasibility. The integrated framework offers a transferable approach for improving urban flood resilience in high-density heritage cities.

Source: Progress in Disaster Science

DOI: 10.1016/j.pdisas.2026.100727