Analysis of Stormwater Runoff Reduction Effects in Urban Areas Through Scenario-based Low Impact Development Techniques

The increase in localized heavy rainfall due to recent climate change, combined with urbanization leading to the expansion of impervious surfaces, has resulted in a rise in urban flooding and various water management challenges. In response, developed countries have adopted decentralized stormwater management strategies to mitigate flooding and protect ecosystems. This study aims to evaluate and analyze the improvement in water balance achieved by applying Low Impact Development (LID) practices to impervious areas with high runoff potential. For this purpose, Andong City Hall and Talchum Park in Andong City, which contain extensive impervious surfaces, were selected as study sites. Andong is in the northern part of Gyeongsangbuk-do Province, South Korea, and is characterized by a temperate climate with distinct seasonal rainfall patterns, making it an ideal location for assessing the effectiveness of LID practices under varying rainfall conditions. A rainfall-runoff simulation model was developed using the Storm Water Management Model (SWMM). In the comparison scenarios, seven LID practices, including infiltration trenches, and bioretention cells, were implemented at Andong City Hall, while eight practices, such as permeable pavement system, vegetated planters, and pervious asphalt, were applied at Talchum Park. To assess the effects under various rainfall conditions, observed 5 rainfall events in Andong and 15 years of long-term rainfall data were used to simulate continuous, long-term, and rainfall scenarios. The results indicate that evapotranspiration and infiltration increased, while runoff significantly decreased after implementing LID practices. Among the methods, permeable pavements exhibited the most effective overall runoff reduction, while vegetated planters demonstrated the greatest runoff reduction efficiency per unit area in Andong.