Water quality in Nakdong river was analyzed using 699 monitoring data sets including flow rates and water quality concentrations collected at 195 tributary monitoring stations (the priority management areas: 35 stations, the non-priority management areas: 160 stations) in 2015. The highest average concentrations of all data for BOD, COD, T-N, T-P, SS, and TOC were 30 600 times higher than the lowest concentrations while the highest average loading rates were 800,000 2,700,000 times higher than the lowest loading rates. Because of the very large differences in the concentrations and loading rates, the variation of the concentrations and loading rates in a priority management monitoring station for BOD, T-P, and TOC was analyzed using the coefficient of variation, the ratio of the standard deviation value to the mean value. For BOD, T-P, and TOC, the coefficients of variation for concentration were mostly less than 100%, whereas the coefficients of variation for loading rate ranged from 31.1% to 232.2%. The very big difference in the loading rates was due to the large variation in flow rates. As a result of this, the estimation of water quality at each monitoring station using the average values of the concentrations and loading rates might be not rational in terms of their representativeness. In this study, new water quality analysis methods using all collected monitoring data were suggested and applied according to the water quality standard in medium-sized management areas.

Abstract
 1. 서 론
 2. 연구 방법
  2.1. 모니터링 지점 현황
  2.2. 중점관리지점 현황
 3. 결과 및 고찰
  3.1. 유량 및 수질 현황
  3.2. 중점관리지점 모니터링 결과 분석
  3.3. 모니터링 결과의 평가
 4. 결 론
 감사의 글
 REFERENCES

• 임태효(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Tae Hyo Im
• 손영규(금오공과대학교 환경공학과, Department of Environmental Engineering, Kumoh National Institute of Technology) | Younggyu Son Corresponding author