Synergistic deployment of green infrastructure and reflective pavements for mitigation of UHI within urban blocks

Abstract

Urbanisation is increasing globally, leading to the Urban Heat Island (UHI) effect, where urban areas experience higher temperatures than nearby rural regions. Mitigating UHI is a significant challenge with far-reaching implications. Green Infrastructure (GI) and reflective pavements have been shown to be effective for UHI mitigation, but extensive use of each can be impractical. By synergistically combining the benefits of both strategies, we can potentially achieve more effective UHI mitigation. Additionally, optimizing their configuration in relation to the surrounding urban morphology can also play a crucial role. This study explored the optimal distribution and configuration of GI and reflective pavements to maximise the cooling effect and cost efficiency in a generic urban block consisting of a regular grid of 25 buildings. A computational fluid dynamics (CFD) based numerical model is developed by solving the steady Reynolds-Averaged Navier-Stokes (RANS) equations to study the impact of GI and reflective pavements on temperature distributions. The climate of Ahmedabad, India, a hot and dry city, was considered. Various configurations of GI and reflective pavements were evaluated, involving a large central park, smaller distributed parks and converting only part of the roads into reflective ones. The findings indicated that the presence of a large central park and partial use of reflective pavements on only half the roads could reduce peak canopy air temperature by 0.16–0.33 °C, with a significantly higher benefit-to-cost ratio as compared to other configurations. These insights contribute to urban design by offering evidence-based solutions for temperature management, promoting sustainability, and enhancing urban quality of life.