• 한국해양환경ㆍ에너지학회지
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• 제2권2호
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• pp.49-59
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• 1999

낙동강 하구역은 담수와 해수가 만나 복잡한 순환양상을 보이는 지역이다 낙동강 하구역은 하구둑의 건설로 혼합체계와 순환양상이 많이 변하였다. 논 연구에서는 낙동강 하구둑 하류부의 해양 물리 환경 변화론 하구둑의 수문개폐에 초점을 맞춰 분석하였다. 관측과 분석에는 3가지의 경우로 나누었다. 1. 평상시 (조시에 따라 수문 개폐) 2. 홍수시 (수문 완전 개방) 3. 갈수시(수문이 완전히 닫혔을시).

• 한국물환경학회지
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• 제25권6호
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• pp.863-871
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• 2009

For the assessment of climate change impacts on river flow condition, CGCM 3.1 T63 is selected as future climate information. The projections come from CGCM used to simulate the GHG emission scenario known as A2. Air temperature and precipitation information from the GCM simulations are converted to regional scale data using the statistical downscaling method known as MSPG. Downscaled climate data from GCM are then used as the input data for the modified TANK model to generate regional runoff estimates for 44 river locations in Nakdong river basin. Climate change is expected to reduce the reliability of water supplies in the period of 2021~2030. In the period of 2051~2060, stream flow is expected to be reduced in spring season and increased in summer season. However, it should be noted that there are a lot of uncertainties in such multiple-step analysis used to convert climate information from GCM-based future climate projections into hydrologic information.

• 한국환경과학회지
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• 제10권4호
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• pp.253-258
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• 2001

A macroeconomic minimodel was simulatedto suggest the public for sustainable us of Nakdong River Basin. The minimodel for the simulation shows the interrelationships between natural environment and economic activity. Topsoil, water, economic assets, and money stock are plotted for 300 years, beginning with 1996 in each simulation. The computer simulation runs suggest that the Nakdong River Basin system in the near future may strongly be influenced by the favorable availability of outside resources, while the economic assets and money stock may be declined by indigenous environmental stock depletion. The simulation run made under the constant decrease in systems purchased inputs with investment ratio of developed country and for sustainable use. The results of simulation shows the recover of natural environment and decrease of economic activity under these condition. Therefore, the economic structure of Nakdong River Basin should be transformed from the present industrial structure to the social-economic structure based on an ecological-recycling concept which depend on renewable resources rather than industrial structural which depend on outside resources.

• 한국물환경학회지
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• 제37권5호
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• pp.369-380
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• 2021

In this work, we analyzed the effects of drought on the water temperature (WT) of Nakdong river basin major river sections using Standardized Precipitation Index (SPI) and WT data. The analysis was carried out on a seasonal basis. After calculating the optimal time scale of the SPI through the correlation between the SPI and WT data, we used the copula theory to model the joint probability distribution between the WT and SPI on the optimal time scale. During spring and fall, the possibility of environmental drought caused by high WT increased in most of the river sections. Notably, in summer, the possibility of environmental drought caused by high WT increased in all river sections. On the other hand, in winter, the possibility of environmental drought caused by low WT increased in most river sections. From the risk map, which quantified the sensitivity of WT to the risk of environmental drought, the river sections Nakbon C, Namgang E, and Nakbon K showed increased stress in the water ecosystem due to high WT when drought occurred in summer. When drought occurred in winter, an increased water ecosystem stress caused by falling WT was observed in the river sections Gilan A, Yongjeon A, Nakbon F, Hwanggang B, Nakbon I, Nakbon J, Nakbon K, Nakbon L, and Nakbon M. The methodology developed in this study will be used in the future to quantify the effects of drought on water quality as well as WT.

• Environmental Engineering Research
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• 제19권3호
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• pp.197-203
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• 2014

This study estimated spatial and seasonal variation of water quality to understand characteristics of Nakdong river basin, Korea. All together 11 parameters (discharge, water temperature, dissolved oxygen, 5-day biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, electrical conductivity, total nitrogen, total phosphorus, and total organic carbon) at 22 different sites for the period of 2003-2011 were analyzed using multivariate statistical techniques (cluster analysis, principal component analysis and factor analysis). Hierarchical cluster analysis grouped whole river basin into three zones, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) based on similarity of water quality characteristics. The results of factor analysis/principal component analysis explained up to 83.0%, 81.7% and 82.7% of total variance in water quality data of LP, MP, and HP zones, respectively. The rotated components of PCA obtained from factor analysis indicate that the parameters responsible for water quality variations were mainly related to discharge and total pollution loads (non-point pollution source) in LP, MP and HP areas; organic and nutrient pollution in LP and HP zones; and temperature, DO and TN in LP zone. This study demonstrates the usefulness of multivariate statistical techniques for analysis and interpretation of multi-parameter, multi-location and multi-year data sets.

• 한국물환경학회지
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• 제18권3호
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• pp.245-251
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• 2002

Reactive dyes waste water, a toxic and refractory pollutant, was treated by an electrochemical method using $Ti/IrO_2$ as anode and Stainless Steel 316 as cathode. In this technique, sodium chloride as an electrolyte was added. A number of experiments were run in a batch system. Artificial samples (reactive blue 19, red 195, yellow 145) were used. Operation parameters, such as supporting electrolyte concentration, current density, pH and sample concentration have been investigated for their influences on COD and color removal efficiencies during electrolysis. After 5 and 90 minites of eletrolysis, color was reduced by 51.5% and 98.9% respectively. Under the condition of current density $10A/dm^2$, NaCl concentration 12mg/l and pH 3, 62.9% of $COD_{Cr}$ was removed after electrolysis for 90 minites. The optimum condition of color removal and COD reduction in this work was found to be the following : pH 3, sodium chloride concentration 20g/l, current density $10A/dm^2$. As a result, we confirmed to be effective to color removal and reduction of refractory organic material.

• 환경위생공학
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• 제22권3호
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• pp.13-26
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• 2007

Changes in the characteristics of dissolved organic matter was studied at selected stations in the Nakdong river basin using physical and chemical methods. Characteristics of dissolved organic matters were analysed and assessed. Production of disinfection byproducts were also investigated. 1. Result of relatedness study among each items of analyses showed that relatedness on BOD values were highest with cattle excrement treatment facilities where there is no synthetic organic materials and relatedness on $COD_{Mn}$ were highest at the mainstream Nakdong river. In case of $COD_{Cr}$ (which has more oxidative power than $COD_{Mn}$), the values were higher in the sidestreams indicating the higher content of recalcitrant compounds. The relatedness values for the $UV_{254}$ also showed higher values in the sidestreams and treatment facilities than mainstream indicating the presence of organic aromatic compounds. 2. Ratio of DOC on total organic carbon were higher in the mainstream which is attributable to the influent particulate organic materials produced by agricultural activities. The values were 10-15% higher in the mainstream compared with sidestreams. 3. Result of biodegradability test indicate that concentrations of recalcitrant DOC were higher in the sidestreams than in the mainstream. The values of recalcitrant DOC were higher with the forest stream indicating the effect of soil oriented humic substances. 4. Result of THM production test carried out at 10 stations in the Nakdong river show that $CHCl_3$ was detected with the highest value and the value was highest at Waekwan station.

• 한국환경과학회지
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• 제26권8호
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• pp.939-953
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• 2017

For the development of flow duration curves for the management of 41 Total Maximum Daily Load (TMDL) units of the Nakdong River basin, first, an equation for estimating daily flow rates as well as the level of correlation (correlation and determination coefficients) was extrapolated through regression analysis of discrete (Ministry of Environment) and continuous (Ministry of Land, Infrastructure and Transportation) measurement data. The equation derived from the analysis was used to estimate daily flow rates in order to develop flow duration curves for each TMDL unit. By using the equation, the annual flow duration curves and flow curves, for the entire period and for each TMDL unit of the basin, were developed to be demonstrated in this research. Standard flow rates (abundant-, ordinary-, low- and drought flows) for major flow duration periods were calculated based on the annual flow duration curves. Then, the flow rates, based on percentile ranks of exceedance probabilities (5, 25, 50, 75, and 95%), were calculated according to the flow duration curves for the entire period and are suggested in this research. These results can be used for feasibility assessment of the set values of primary and secondary standard flow rates for each river system, which are derived from complicated models. In addition, they will also be useful for the process of implementing TMDL management, including evaluation of the target level of water purity based on load duration curves.

• 한국해양학회지:바다
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• 제17권2호
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• pp.120-129
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• 2012

낙동강 하구에 위치한 갯벌 퇴적물에서 2005년 7월부터 2006년 9월까지 퇴적물-수층을 통한 산소와 용존 무기질소 플럭스, 그리고 탈질소화율을 계절별로 조사하였다. 현장 조건 수온에서 퇴적물 배양을 통해 측정된 산소 플럭스의 범위는 $-37.0{\sim}0.5mmol\;O_2\;m^{-2}\;d^{-1}$이었고, 수온이 증가할수록 퇴적물에 의한 산소소모가 많아져, 수층에서 퇴적물로의 산소 플럭스가 증가하였다. 탈질소화율은 $4{\sim}2732{\mu}mol\;N\;m^{-2}\;d^{-1}$의 범위로 같은 방법으로 측정한 국내 연안의 결과보다 높은 값을 나타냈고 산소 플럭스와 유사한 계절변화를 보였다. 질소동위원소를 이용하여 측정된 탈질 소화율은 수층에서 퇴적물로 유입되는 질산염 플럭스와 높은 상관관계를 보였다. Isotope pairing technique에서 계산되는, 총 탈질소화 중 "수층에서 유입된 질산염을 이용하는 탈질소화($D_w$)"도 수층에서 유입되는 질산염 플럭스와 양의 상관 관계를 보여 수층에서 유입되는 질산염이 탈질소화의 계절변동의 원인임을 시사하였다. 여름철에 질산염농도가 높은 담수의 유입 증가가 낙동강 하구 퇴적물로의 질산염 유입과 탈질소화를 촉진시킨 것으로 추정된다. 낙동강 하구 퇴적물에서 생지화학적 과정의 일반적인 패턴 및 경향을 파악하기 위하여, 이 연구에서 측정된 여러 생지화학적 플럭스를 방향과 크기에 따라 분류하여 보았다. 그 결과, 수온과 질산염 유입 변화에 따라서 여름철에는 수층에서 퇴적물로의 산소와 질산염 플럭스가 높게 나타나고 탈질소화도 높은 반면, 여름철을 제외한 나머지 시기에는 이들 플럭스가 낮아, 갯벌 퇴적물의 생지화학적 과정이 낙동강 담수 유입에 민감하게 반응함을 알 수 있었다.

• 한국수자원학회논문집
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• 제56권3호
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• pp.165-171
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• 2023

낙동강 하구둑은 담수와 해수가 만나는 감조하천 환경으로 하구둑에서 방류하는 지표수 유출량과 연안 해저 지하수 유출량에 대한 모니터링이 체계적으로 요구된다. 본 연구에서는 낙동강 하구둑 상류 지역에 위치한 수위자료와 물수지분석을 통하여 변화 저수량과 방류량을 계산하였다. 해저를 통한 육상에서의 지하수 유출도 원격탐사 기반 지형자료와 수문 모델링 자료를 근거로 산출하여 낙동강 하구둑 유출량과 비교 분석하였다. 제안된 방법은 현장 측정 이외의 원격탐사 기반 고도계 자료를 활용하여 수자원 관리에 효율적으로 적용할 수 있을 것으로 판단된다. 담수 지표수 유출량 뿐만 아니라 해저 지하수 유출이 연안에 미치는 영향이 크기 때문에, 낙동강 하구둑 생태계 모니터링에서 담수와 해수의 상호 관계에 대한 연구도 충분히 고려되어야 할 것으로 사료된다.