A Study on the Salinity Variation of Salt Water in an Estuary

하구(河口)의 해수(海水)의 염도변동(鹽度變動)에 관한 연구(研究) - 군산외항(群山外港)부근을 중심(中心)으로 -

Since the estuary is a very complex place in which the sea water and the fresh water meet, it is very difficult to make a general analytical description of salinity distribution in the estuary. As an attempt to investigate the characteristics of salinity variation in the estuary of the Geum River, the field observations were continuously carried out at three points near the Gunsan New Harbor at the time intervals 1 to 1.5 hours during one tidal cycle and the data were analysed. The following results were obtained; 1. It was reconfirmed that most of the ratios of the salinity to the conductivity were widely distributed between the range of 0.5 to 1.0. 2. The salinity showed the peak at the high water, and then it began to decrease gradually and had the lowest value 0 to 2 hours after the low water. 3. The density current was generally the intense mixing type and when the river discharge was very large it was of the moderate type. 4. The vertical salinity distribution was not significantly affected by the wave height. 5. The maximum vertical salinity differences were generally less than 10 g/l and the time of the occurrence of the minimum value was 0 to 3 hours after the low water when in the spring tide and in the neap tide it occurred 2 to 3 hours after the high water.

하구(河口)는 해수(海水)와 담수(淡水)가 만나는 아주 복잡(複雜)한 지점(地點)으로 하구(河口)에서의 염도분포(鹽度分布)에 대한 수리학적(水理學的)인 일반적(一般的)인 해석(解析)은 대단히 어렵기 때문에 본(本) 연구(硏究)에서는 현지관측(現地觀測)을 통(通)하여 염도(鹽度)의 분포특성(分布特性)을 알기 위하여 조차(潮差)가 큰 군산(群山) 외항(外港)부근의 3지점(地點)에서 조석일주기(潮汐一週期)동안 1~1.5시간 간격으로 연속적(連續的)으로 현지관측(現地觀測)을 실시하였으며 분석결과(分析結果) 다음과 같은 몇가지 결론(結論)을 얻었다. 1. 염도(鹽度)와 전기전도도와의 비(比)가 0.5~1.0 사이에 대부분(大部分)이 산만하게 분포(分布)되어 있음이 재확인(再確認)되었다. 2. 염도(鹽度)는 만조시(滿潮時)에 가장 크고 만조(滿潮)에서 간조(干潮)로 됨에 따라 점점 작아져서 간조후(干潮後) 0~2시간(時間) 사이에 가장 작았다. 3. 금강하구(錦江河口)의 밀도류(密度流)는 대체로 강혼합형(强混合型)이었고 유량(流量)이 클 때는 완혼합형(緩混合型)이었다. 4. 연직염도분포(鉛直鹽度分布)에 파고(波高)의 영향은 별(別)로 없었다. 5. 최대연직염도차(最大鉛直鹽度差)는 대체로 10g/l 이하(以下)였으며 최소치(最少値)가 나타나는 시기(時期)는 대조시(大潮時)에는 간조후(干潮後) 0~2시간후(時間後)였고 소조시(小潮時)에는 만조후(滿潮後) 2~3시간(時間) 후(後)에 나타났다.