Comparative Analysis of Summer Temperature Reduction Effects of Urban Ground Fountains and Natural Streams

Urban environments increasingly suffer from extreme heat due to climate change and urban heat island effects. This study compares the summer temperature reduction ef-fects of two contrasting cooling infrastructures: a ground fountain located in Dongtan Yeoul Park—a newly developed smart city district experiencing rapid urbanization, and a natural stream in Chilrangi Valley in Sangdong-eup, the coolest rural location in South Korea during summer. Using on-site IoT-based weather stations, thermal imag-ing, and microclimate monitoring, we analyzed air temperature, surface temperature, Mean Radiant Temperature (MRT), and Universal Thermal Climate Index (UTCI) at various distances from each water source. The ground fountain showed a maximum air temperature reduction of 2.26°C within a 5-meter radius, with MRT and UTCI re-ductions of up to 3°C compared to adjacent dry zones. However, cooling effects di-minished rapidly with distance. In contrast, the natural stream maintained an average air temperature of 25.5°C—approximately 10°C lower than the urban site—along with more stable MRT (~40°C) and UTCI (~45°C) throughout the day. These findings indi-cate that while ground fountains provide localized, short-term relief, natural systems deliver broader and more sustainable cooling. This study highlights the importance of integrating both artificial and natural water-based infrastructures to enhance thermal comfort and support climate-resilient urban planning.