Recently, South Korea has been increasingly experiencing large changes in precipitation patterns, in particular, a storm may transition from a mild to a torrential rainfall within a few hours, which may ignite extreme urban flood inundation. This urban flood inundation is increased mainly by changing landcover, which is characterized by an increase of impervious cover across urban and sub-urban areas. This study evaluates a volume of the urban flood resulting from a manhole overflow in the stormsewer systems in the city of Andong, South Korea, under changing landcover conditions. Due to lack of data, this model still shows challenges to incorporate flooding of those subwatersheds that are not routed to the stormsewer network. Simulations are conducted using EPA SWMM, which is a widely used program for modeling urban flood inundation. The simulation is performed using synthesized rainfall derived from intensity-duration-frequency curves of Andong City for different imperviousness scenarios. The results indicate an increase in about 5% flood volume when imperviousness increased from 20% to 80%. Numerical experiments also reveal that combining 1D-SWMM model with spatial analysis in GIS environment allow to analyze urban flood with the limited input dataset. This study is also expected to be a backbone of the upcoming application research/projects in South Korea to address urban flood inundation issues induced by torrential rainfall occurrences.
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