Two sites with different average daily traffic volume at an intersection were selected in order to investigate water quality of the first flushes in the surface runoffs. The effects of rainfall intensities and accumulated non-rainy days before rainfall events on the water quality were also delineated. Samples were collected at every 2 min. interval from each first flush from February to May, 2004 for 4 major rainfall events. CODcr or SS concentrations at the site with an average daily traffic volume (ADTV) of 23,000 vehicles were 2-7 times higher than those at the site with an ADTV of 1,400 vehicles. The longer the accumulated non-rainy days were, the higher the concentration of heavy metals were than those of CODcr and SS in the first flushes.

• 임세호(연세대학교 토목환경공학과) | Se Ho Lim
• 이지영(연세대학교 토목환경공학과) | Ji Young Lee
• 고광백(연세대학교 토목환경공학과) | Kwang Baik Ko
• 최상용(연세대학교 토목환경공학과) | Sang Yong Choi Corresponding Author