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DOI : 10.17640/KSWST.2016.24.6.161 , Vol.24, No.6, 161 ~ 170, 2016
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| Title |
| Long-Term Variations of Water Quality and Material Flux in the Nakdong River, Korea |
| 윤상철 Sang-chol Yoon , 윤석현 Shyun-hyun Yoon , 이승목 Seung-mok Lee , 윤이용 Yi-yong Yoon |
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| Abstract |
| We analyzed temperature, dissolved oxygen(DO), ammonia, nitrate, phosphate, chlorophyll-a of Nakdong river estuary discharged flow from Feb. to Dec. 2015. and We studied Nakdong river water`s environmental element for 20 years(1996-2015) to understand long term variation of the water quality and discharge flow of Nakdong river water. Although the change pattern of total discharge flow was similar to annual variation of precipitation, discharge flow decreased over 67%(7.572×106 ㎥·year-1) after construction of Nakdong river barrage(2013-2015). The annual range of fluctuation also largely decreased. We conducted the study the annual variation of environmental elements for 20 years. The concentration of nitrate, ammonia, chlorophyll-a remarkably decreased. The concentration of DO has increased until 2012 and has decreased after construction on Nakdong river barrage. The fluctuation range of ammonia and chlorophyll-a was large with the change of discharged flow at flowing a small amount of discharged water. Dilution effect was remarkable at flowing a large amount of discharged water(over 300,000 ton·day-1). The concentration of COD, nitrate, phosphate was not decreased even though discharged flow was increased. The concentration of SS was increased with discharge flow increase. But the fluctuation range of the concentration of environmental elements was large even though a small amount of discharged water(100,000 ton·day-1) flow after construction of Nakdong river barrage(2012). The discharged flow of all environmental elements we studied has decreased. COD, ammonia, nitrate, phosphate, chlorophyll-a and SS has decreased by 29.5 kt·year-1, 2.8 kt·year-1, 19.9 kt·year-1, 1.8 kt·year-1, 75.0 kt·year-1, 402.5 kt·year-1 for 20 years. In conclusion the discharged flow of all environmental elements we studied has decreased after construction of Nakdong river barrage (2012) and the range of fluctuation was also being small. |
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| Key Words |
| Nakdong estuary, barrage, long term variations, nutrients, chlorophyll-a |
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