Abstract

To know characteristics of water quality in coastal sea around the Keum river estuary in summer, we studied the water quality of surface, middle and bottom level during Jun e～september, 1998. The mean concentrations of COD, DIN, DIP & chlorophyll-a were 1.36mg/L, 28.60㎍-at/L, 0.48㎍-at/L and 4.14㎍/L, respectively, which were over eutrophication criteria in sea water. After the Keum river dyke was constructed, seasonal freshwater discharge was largely changed. About 80% of total annual freshwater discharge was concentrated in summer as rainy season from July to September. The correlation coefficient of DIN versus salinity was shown to be high, and thus the concentration of DIN was closely related to freshwater discharge. Maximum Chlorophyll-a concentration was occurred in September, due to increased DIP concentration, high water temperature and low salinity after heavy rainfall in August. The results of Principal Component Analysis showed that the first factor represented a series of eutrophication factors, the second factor w3s a valiance of seasonal fluctuation, and the third was a variance of progress of mass change.

1998년 하계(6～9월)에 금강하구 주변 해역 11개 정점을 조사하여 공간적인 수질변통 특성을 파악하고, 통계분석 기법의 하나인 요인분석을 동하여 하계 금강하구 주변해역에서의 수질변동 지배요인을 분석하였다. 조사기간 동안 금강하구 주변해역의 화학적산소요구량의 평균농도는 1.36mg/L, 용존무기질소의 평균농도는 28.60㎍-at/L, 용존무기인의 평균농도는 0.48㎍-at/L로 나타났으며, 주성분분석 결과 전체 수질변동의 약 43%를 차지하는 제 1주성분 요인이 담수 유입과 밀접한 관련이 있는 영양염류와 염분의 변화로 나타나, 담수변통 요인이 중요한 역할을 하는 것으로 나타났다.

Keywords

• Keum river estuary;
• water quality characteristic;
• Principal component analysis;
• correlation coefficient