Urban areas face increasing flood risks due to climate change, intensified rainfall events, and high impervious surface coverage. Blue-Green Roofs (BGR) have emerged as a nature-based solution to retain stormwater, while Smart BGR systems integrate active control functions to enhance performance under varying rainfall conditions. This study evaluated the rooftop-scale runoff reduction efficiency of conventional roofs, BGR, and Smart BGR using 31 monitored rainfall events in 2024, while eight years of historical rainfall data (2017–2024) were used only to characterize long-term rainfall patterns in the study area. A multiple-linear regression analysis was performed for exploratory trend identification between rainfall characteristics and runoff reduction; variables unrelated to short-term storm responses such as evapotranspiration or initial storage were beyond the study scope. Results showed that the annual runoff per unit area was 1.115 m³/m² for conventional roofs, 0.547 m³/m² for BGR, and 0.128 m³/m² for Smart BGR, corresponding to reduction rates of 50.98% and 88.53% for BGR and Smart BGR, respectively. In higher rainfall classes, Smart BGR maintained significantly higher performance: for Class 3 (average 53.00 mm), BGR reduced runoff by 54.89% while Smart BGR achieved 86.71%; for Class 4 (average 121.21 mm), the rates were 54.68% and 90.00%, respectively. These findings indicate that Smart BGR’s storage optimization and controlled discharge enable superior effectiveness during intense and prolonged events. The study highlights Smart BGR’s potential as an advanced stormwater management technology, offering clear advantages over both conventional roofs and passive BGR designs. Limitations include the need for testing under more extreme rainfall scenarios, optimization of operational strategies, and economic feasibility assessments. Nevertheless, Smart BGR represents a promising approach for enhancing urban flood resilience in the context of climate change.

Permeable blocks have been increasingly adopted as climate adaptation technologies to mitigate the impacts of extreme rainfall in urban areas. However, quantitative runoff reduction performance under varying rainfall intensities has not been sufficiently validated. In this study, controlled outdoor artificial rainfall experiments were conducted under three rainfall scenarios (50, 100, and 150 mm/h) to evaluate the effectiveness of permeable blocks in reducing surface runoff. A runoff monitoring system was installed at a testbed site on the Yangsan campus of Pusan National University to quantify outflow characteristics. The experimental data were used to develop a runoff prediction model based on an exponential regression approach. The results showed that the permeable blocks effectively reduced runoff across all rainfall scenarios, with correlation coefficients between the observed and predicted values ranging from 0.991 to 0.995 (p < 0.05). This indicated a strong predictive relationship and verified the reliability of the model. These findings contribute to the establishment of experimental design guidelines for future high-precision climate simulation experiments and support the practical implementation of permeable pavement systems for urban flood mitigation.

With the increasing frequency of heat-based climate disasters due to recent climate change, various technologies are being developed to mitigate their impacts. Blue-green roofs (BGR) is a technology that consists of rainwater storage tanks and grass layers installed on building rooftops to reduce the infiltration of cold or heat into the building interiors. This study analyzed the indoor temperature changes between two buildings with equal rooftop area, one equipped with a BGR and the other without, during winter season to evaluate their heating effects. The results indicated an average heating effect of 0.56 °C across the entire monitoring period for the building with a BGR. The heating effect was observed only at temperature ranges below 6.5 °C, with no effect at higher temperatures. This study suggests that even installing a roof-based system can provide some degree of heating benefits. Further research and development are needed to improve the heating efficien through additional technological advancements.