Characteristics of Temporal Variation on Water Quality (T-P, T-N, COD_Mn, SS, BOD₅) in the Jungrang Stream during Rainfall Event

Abstract

Water quality variations were investigated at 4 locations of Jungrang river (upper, middle and lower basins) during a period of 3 rainfall events. During the rainfall, concentrations of CODMn, SS and BOD5 significantly increased, while the concentration of T-N decreased and that of T-P remained relatively constant. This pattern became more apparent as the level of accumulative precipitation and rainfall intensity increased. Simple regression analysis showed that the accumulative precipitation was positively correlated with all water quality pollutants except for T-N. With increasing accumulative precipitation, the concentration of T-N decreased, while the others increased. R 2 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 average rainfall intensity, the more T-N and T-P in the upper basin, more CODMn in the middle and lower basins, more SS with gradual increase from upper to lower areas, and more BOD5 with gradual decrease from upper to lower region. Simple regression showed that water quality pollution in the upper basin was more sensitive to an increase of rainfall discharge than that in the middle and lower areas.

The Relationship between Rainfall Pattern and Epilithic Diatoms in Four Streams of Central-Western Korea for Three Years (2013–2015)

“…To create the land use map around the survey sites for each river, a radius of 50 m from the sampling place was divided into urban, forest, agriculture, industrial complex, and livestock categories. To identify the soil characteristics in the survey sites, a radius of 50 m from the sampling place was categorized into A, B, C, and D classes (Table 1) based on data from the Regional Land Management Office [12][13][14][15]. To investigate the water quality in the survey sites, water temperature, dissolved oxygen (DO), pH, electrical conductivity, and turbidity were directly measured in the field using the Horiba U-50 mobile water quality meter.…”

“…Population increases and industrial development in recent years have changed the watershed environment, and industrial wastewater and urban sewage now pollute the waters [11][12][13]. A rapid change in water quality follows rainfall, floods, and intensive rainfalls during the monsoon period [14], and the pollution loads in downstream areas are largely due to the influx of surface water and tributaries [15].…”