In this study, it is an object to develop a regression model for the estimation of TOC (total organic carbon) concentration using investigated data for three years from 2010 to 2012 in the Gam Stream unit watershed, and applied in 2009 to verify the applicability of the regression model. TOC and CODMn (chemical oxygen demand) were appeared to be derived the highest correlation. TOC was significantly correlated with 5 variables including BOD (biological oxygen demand), discharge, SS (suspended solids), Chl-a (chlorophyll a) and TP (total phosphorus) of p<0.01. As a result of PCA (principal component analysis) and FA (factor analysis), COD, TOC, SS, discharge, BOD and TP have been classified as a first factor. TOCe concentration was estimated using the model developed as an independent variable BOD5 and CODMn. R squared value between TOC and measurement TOC is 0.745 and 0.822, respectively. The independent variable were added step by step while removing lower importance variable. Based on the developed optimal model, R squared value between measurement value and estimation value for TOC was 0.852. It was found that multiple independent variables might be a better the estimation of TOC concentration using the regression model equation(in a given sites).

Abstract
 1. 서론
 2. 재료 및 방법
  2.1. 대상유역 및 자료분석
  2.2. 상관분석
  2.3. 회귀분석
  2.4. 주성분 분석 및 요인분석
 3. 결과 및 토의
  3.1. 수질특성분석
  3.2. 상관분석
  3.3. 주성분 분석 및 요인분석
  3.4. 회귀모형의 개발
  3.5. 회귀모형의 적용성 평가
 4. 결론
 REFERENCE

• 정강영(국립환경과학원 낙동강물환경연구소) | Kang-Young Jung (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 안정민(국립환경과학원 낙동강물환경연구소) | Jung-Min Ahn (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 이경락(국립환경과학원 낙동강물환경연구소) | Kyung-Lak Lee (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 김신(국립환경과학원 낙동강물환경연구소) | Shin-Kim (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 유재정(국립환경과학원 낙동강물환경연구소) | Jae-Jeong Yu (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 천세억(국립환경과학원 낙동강물환경연구소) | Se-Uk Cheon (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER)
• 이인정(국립환경과학원 낙동강물환경연구소) | In Jung Lee (Nakdong River Environment Research Center, National Institute of Environmental Research, NIER) Corresponding author