Evaluating the Impact of Urban Stormwater Runoff by Street Tree Canopy

Impervious area increase by urbanization and flash flood by climate change lead to abrupt increase in urban stormwater, unlike in the past. Currently, street trees play a significant role in urban environmental improvement such as green space, urban heat reduction, and air pollution reduction. In addition, transpiration from leaf canopy in an urban water cycle significantly impacts the decrease in urban stormwater runoff. In this study, leaf canopy, as in earlier areas, was evaluated for the impact of decreasing urban stormwater. US Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) for urban stormwater runoff, Geographic Information System (GIS) for its input extraction, and image process for calculating the leaf canopy area were utilized. The simulation results indicated that flood runoff peak based on 20 frequency of sewer facility standard and 80 frequency of local river design standard decreased by 1.08% and 1.44%, respectively.