강우 시 중랑천 유역의 수질(T-P, T-N, CODMn, SS, BOD5)변화 특성

Water quality variations were investigated at 4 locations of Jungrang river (upper, middle and lower basins) during aperiod of 3 rainfall events. During the rainfall, concentrations of CODMn, SS and BOD5 significantly increased, while the concentrationof T-N decreased and that of T-P remained relatively constant. This pattern became more apparent as the level of accumulativeprecipitation and rainfall intensity increased. Simple regression analysis showed that the accumulative precipitation was positivelycorrelated with all water quality pollutants except for T-N. With increasing accumulative precipitation, the concentration of T-Ndecreased, while the others increased. R2 of simple regressions of hourly average rainfall intensity and water quality pollutants,showed wider range of variation ranged from 0.483 to 0.992, which indicated a strong correlation. The stronger the hourly averagerainfall intensity, the more T-N and T-P in the upper basin, more CODMn in the middle and lower basins, more SS with gradualincrease from upper to lower areas, and more BOD5 with gradual decrease from upper to lower region. Simple regression showedthat water quality pollution in the upper basin was more sensitive to an increase of rainfall discharge than that in the middle andlower areas.