Enhancing daytime cooling effect in river network cities: Balancing coordination between river network structures and riverfront built environment forms in Hangzhou

The cooling effect of urban rivers is critical in mitigating the surface urban heat island (SUHI) effect. Existing studies mainly examine individual rivers, while the impact of dense river networks and their riverfront built environments remain underexplored. This study presents a method to accurately analyze the impact of river network structure and riverfront morphology on daytime river cooling distance (RCD) and river cooling index (RCI). The results showed that the river network in central Hangzhou had an average RCD of 120 m and an average RCI of 1 °C, with the cooling effect being most pronounced within 150 m of the riverbank. The river network structure was identified as the primary factor influencing river network cooling effect (RNCE), with river width having the greatest impact on cooling performance. Wider rivers produced stronger cooling effects, followed by network density. The riverfront built environment emerged as a secondary factor, with vegetation coverage being a key indicator. A coverage rate of 30 % and a concentrated planting layout significantly enhanced RNCE, with RCI reaching 1.8 °C and RCD extending to about 140 m. Additionally, the distance between buildings and rivers was essential, as development too close to the river limited RNCE. This study guides the optimization of urban river network, enhances daytime thermal comfort, and informs sustainable riverfront development in comparable urban environments. • This study investigates the cooling effect of river networks in high-density urban areas, using Hangzhou as a case. • A novel method maps RNCE boundaries and intensity at 30m × 30 m resolution for improved spatial accuracy. • Identifies how river networks and waterfronts shape RNCE and proposes land-use-based strategies to enhance it.