냉배수 유입에 따른 진해만의 수질 변동 예측

Abstract

In order to evaluate the effect of cold water discharge from Tongyeong LNG station on changes of water quality and primary production of Jingae Bay, tidal current model(Princeton Ocean Model) considering the cold water discharge was simulated during a year(2018.01.01. ∼ 2019.01.01.). Base on the model results, PEA(stratification strength parameter), space-specific growth rates of phytoplankton and macroalgae(Saccharina japonica) in Jinhae Bay were estimated. And DO concentration in Jinhae Bay with various volume of cold discharge was predicted using Gaussian Process Regression method. In case of discharge volume of 10 m3 sec-1, the changes in environment of the Jinhae Bay due to cold discharge were very insignificant. The effects of cold discharge were most pronounced in May(except stratification strength(Aug) and primary production(Nov)), the results of discharge volume of 1000 m3 sec-1 in May are as follows: Water temperature in near-by discharge outlet was decreased up to ca. –5.35℃ and -4.05℃ respectively in the surface and bottom layers. The PEA in near-by Geoje-Gaduk open boundary increased up to ca. 23 J m-3, it has increased by more than 5 J m-3 in area of ca. 104 km2 of Jinhae Bay in Aug. While the water temperature decrease by cold discharge reduced primary production(PP) of phytoplankton in the center of bay to ca. 15% in Nov, it promoted net growth rate of macroalgae in Haengam Bay up to ca. 7% in May. The DO concentration in the center of bay was predicted to increase ca. 1.01 mg L-1 due to water temperature decrease. From the above results, we confirmed that the environmental changes in Jinhae Bay by cold discharge from Tongyeong LNG production base are very insignificant. As a results of discharge volume of 1000 m3 sec-1, it is expected that special purposes utilize of cold discharge (water temperature reduction, red tide prevention, macroalgae growth, and DO increase) will be possible in small-areas considering actual discharge volume.