Case study on urban water cycle improvement in Andong City using the SWMM-LID model

As global warming accelerates, the frequency and intensity of localized heavy rainfall events are increasing, leading to severe urban flooding and substantial inundation damage downstream. Urban areas with high impervious surfaces are particularly vulnerable, as rapid stormwater runoff during rainfall exacerbates flood risks. This study investigates the runoff reduction effects of Low Impact Development (LID) techniques applied through the Storm Water Management Model (SWMM) to mitigate urban runoff. Andong City Hall and Talchum Park in Andong City were selected as study sites to compare water balance changes before and after LID installation. The analysis revealed that after implementing LID techniques, evaporation increased by 9.8% to 12.5%, infiltration increased by 111.0% to 139.2%, and runoff decreased by 31.8% to 38.8%. These results indicate that LID techniques effectively enhance water evaporation and infiltration, improving the water cycle in highly impervious areas and mitigating urban flooding and inundation damage.