Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.

1. 서 론
 2. 재료 및 방법
  2.1. 대상유역
  2.2. 연구방법
 3. 결과 및 고찰
  3.1. The seasonal-kendall test
  3.2. Self-organizing maps
 4. 결 론
 REFERENCES

• 안정민(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Jung-Min Ahn
• 이인정(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | In-Jung Lee
• 정강영(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Kang-Young Jung
• 김주언(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Jueon Kim
• 이권철(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Kwonchul Lee
• 천세억(국립환경과학원 낙동강물환경연구소, Nakdong River Environment Research Center, National Institute of Environmental Research) | Seuk Cheon
• 류시완(창원대학교 토목공학과, Department of Civil Engineering Changwon National University) | Siwan Lyu Corresponding author