The study looked at how rain affects pollution runoff in urban and mountainous areas. They found that urban areas had higher runoff than mountainous areas. In Dalseo, 49.3% of the area is urban, with a runoff coefficient of 0.49. In Daemyung, 20.5% is urban, with a runoff coefficient of 0.16. The correlation between rainfall and peak flow was stronger in Dalseo than in Daemyung. The relationship between dry periods and runoff was also stronger in Dalseo. The amount of sediment in the runoff was higher in Dalseo compared to Daemyung.