Understanding the cooling mechanisms of urban canal-edge walkways through blue–green infrastructure: a parametric ENVI-met study

Urban canal-edge spaces are increasingly recognised as important blue–green infrastructure for mitigating urban heat; however, the mechanisms governing pedestrian thermal comfort in these environments remain insufficiently understood. This study employed a validated ENVI-met model to investigate the effects of canal orientation, canal width, water bodies and riparian tree configuration on pedestrian thermal comfort under summer heatwave conditions in Manchester, UK. A total of 32 scenarios were simulated to quantify the individual and combined effects of these design factors. Canal water alone provided only moderate daytime cooling, with its effectiveness depending strongly on canal orientation and local ventilation conditions. In contrast, riparian trees substantially improved thermal comfort through reductions in mean radiant temperature associated with canopy shading. Furthermore, the study identified that thermal performance was influenced not simply by the presence of blue and green infrastructure, but by their interaction. Rather than acting as the dominant cooling source, canal water enhanced the cooling effectiveness of adjacent vegetation, while continuous canopy shading emerged as the principal mechanism controlling pedestrian thermal comfort. These findings provide new insights into the mechanisms of canal-edge cooling and offer quantitative evidence to support climate-responsive design of thermally comfortable and resilient urban waterfronts.