• Journal of Korea Water Resources Association
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• v.44 no.6
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• pp.477-486
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• 2011

The objective of this study is to investigate the water pollution problems brought about by the construction of eco-friendly waterfront space through the physical model experiment including water quality consideration. Due to the lack of water supply into the artificial ponds and canals, the water quality problems such as eutrophication, odor and so on can be occurred. There have been many numerical models on such phenomena but limited studies using physical test due to the difficulty in the verification of physical interpretation of the study area. In this study, a prototype model that is not affected by the dimensionless parameters was carried out, where unpolluted water is mixed into the contaminated water to reduce the concentration of nutrients. In addition, this study also attempt to find the optimal configuration of the flow induction machines using the scale model which will evaluate and verify the effectiveness of the enforcement methods to maintain the water quality objectives.

• Journal of Korea Water Resources Association
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• v.46 no.11
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• pp.1115-1128
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• 2013

The purpose of this study is to evaluate the suspended solids and eutrophication processes relationships in Chungju lake using CE-QUAL-W2, two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model. For water quality modeling, the lake segmentation was configured as 7 branches system according to their shape and tributary distribution. The model was calibrated (2010) and validated (2008) using 2 years of field data of water temperature, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and algae (Chl-a). The water temperature began to increase in depth from April and the stratification occurred at about 10 m early July heavy rain. The high SS concentration of the interflow density currents entering from the watershed was well simulated especially for July 2008 heavy rainfall event. The simulated concentration range of TN and TP was acceptable, but the errors might occur form the poor reflection for sedimentation velocity of nitrogen component and adsorption-sediment of phosphorus in model. The concentration of Chl-a was simulated well with the algal growth patterns in summer of 2010 and 2008, but the error of under estimation may come from the use of width-averaged velocity and concentration, not considering the actual to one side inclination by wind effect.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.14-30
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• 2007

The purpose of this study was to evaluate trophic conditions of various Korean reservoirs using Trophic State Index (TSI) and predict the reservoir conditions by empirical models. The water quality dataset (2000, 2001) used here were obtained from the Ministry of Environment, Korea. The water quality, based on multi-parameters of dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), suspended solid (SS), Secchi depth (SD), chlorophyll-${\alpha}$ (CHL), and conductivity largely varied depending on the sampling watersheds and seasons. In general, trophic conditions declined along the longitudinal axis of headwater-to-the dam and the largest seasonal variations occurred during the summer monsoon of July-August. Major inputs of TP occurred during the monsoon (r=0.656, p=0.002) and this pattern was similar to solid dynamics of SS (r=0.678, p<0.001). Trophic parameters including CHL, TP, SD, and TN were employed to evaluate how the water systems varies with season. Trophic State Index (TSI, Carlson, 1977), based on TSI (CHL), TSI (TP), and TSI (SD), ranged from mesotrophic to eutrophic. However, the trophic state, based on TSI (TN), indicated eutrophic-hypereutrophic conditions in the entire reservoirs, regardless of the seasons, indicating a N-rich system. Overall, nutrient data showed that phosphorus was a primary factor regulating the trophic state. The relationships between CHL (eutrophication index) vs. trophic parameters (TN, TP, and SD) were analysed to develop empirical models which can predict the trophic status. Regression analyses of log-transformed seasonal CHL against TP showed that the value of $R^2$ was 0.31 (p=0.017) in the premonsoon but was 0.69 (p<0.001) during the postmonsoon, indicating a greater algal response to the phosphorus during the postmonsoon. In contrast, SD had reverse relation with TP, CHL during all season. TN had weak relations with CHL during all seasons. Overall, data suggest that TP seems to be a good predictor for algal biomass, estimated by CHL, as shown in the empirical models.

• Korean Journal of Ecology and Environment
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• v.35 no.1 s.97
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• pp.28-35
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• 2002

The effect of physical parameters on water quality was analyzed using monitoring data of 193 agricultural reservoirs. The retention time of reservoirs ($t_d$) ranged between 10 and 140 days, and the ratio of drainage area (DA) to reservoir surface area (SA) was between 10 and 120. Both ratios of DA/SA and total area (TA)/ reservoir storage (ST) in Korean agricultural reservoirs were relatively greater than those in natural lakes in other countries. As retention time was plotted against DA/SA ratio, it was shorter in Korean reservoirs than natural lakes. The semi-logarithmic relationship between TA/SA and t>$t_d$ was $t_d\;=\;42.21(TA/ST)^{-1}$ (n = 50, $R^2\;=\;0.89$). While areal loading of total phosphorus (TP) was below $4\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in general, it exceeded $10\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in reservoirs where DA/SA ratio was greater than 100, which implies that areal loading of TP increases as DA/SA ratio increases. Chl-a concentration was positively related with the mean depth of reservoir, implying the higher Chl-a concentration with deeper the mean depth. Therefore, the deeper reservoir might be advantageous in water quality management perspective if other morphological conditions are similar. The empirical regression equation using physical parameters was also suggested in the estimation of TP concentration in the reservoirs. Combined information presented in this paper might be applicable to the water quality management in agricultural reservoirs.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.251-251
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• 2020

원주시를 비롯한 남한강 지류인 섬강의 중·하류 지역에서의 물 부족 및 수해를 방지를 위하여 남한강 지류인 섬강 유역에 횡성댐이 건설되었다. 그러나 상수원으로 이용되는 타 댐에 비해 횡성댐의 최근 5년간 TOC와 BOD₅의 평균 농도가 높은 것으로 나타났다. 횡성댐 유역의 수질 오염은 원주시와 횡성군의 식수원인 횡성호의 수질에도 악영향을 미치게 되어 이에 대한 개선책이 필요하다. 이에 본 연구에서는 횡성댐 유역의 주요 유입하천을 대상으로 오염원 현황을 파악하고 홍수기 유량·수질 모니터링을 통한 오염원 특성 및 기여도를 분석하였다. 이를 바탕으로 SWAT 모형을 구축한 후 횡성댐 유역 내 주요 우심하천인 구사천과 횡성댐 말단 지역에 대해 적용 가능한 총 5가지의 수질개선 대책 시나리오를 구성하여 유역 모델링을 통한 전체유황, 홍·풍·평수기, 저·갈수기 수질 오염 저감 효과를 분석하였으며, 추가적인 수질개선 대책으로 지역적 특성을 반영하여 오염원별 다양한 관리대책을 제시하였다. 우심하천인 구사천의 경우 마을하수도 설치에 대한 오염부하 저감 효과와 벌목에 대한 오염부하 영향에 대한 시나리오를 모델 내 적용하여 분석하였다. 또한 횡성댐 유역 말단에 대해 비가림시설 및 유출방지턱 설치에 따른 오염부하 저감 효과, 표준시비량 적용 및 농업BMPs(물꼬관리, 완효성비료, 볏짚피복, 초생대)에 따른 오염부하 저감 효과를 분석하였다. 시나리오별 수질개선 효과를 분석한 결과, BOD₅는 최소 0.1 ~ 11.6%의 수질개선 효과가 있었으며, T-N은 0.1 ~ 22.3%, T-P는 0.1 ~ 31.8%, TOC는 0.1 ~ 3.8%의 수질개선 효과가 있는 것으로 나타났다. 각 수질항목별 시나리오를 분석한 결과, 비가림시설 및 유출방지턱과 축산분뇨 위탁처리 시나리오, 경작지 표준 시비량 시비 및 농업 최적관리 적용 시나리오의 오염원 저감 효율이 가장 높은 것으로 나타났다. 향후 본 연구에서 제시한 오염저감 시나리오와 수질개선 대책 등을 통해 도출된 결과는 횡성댐 유역의 수질 개선을 위한 대책 수립에 기여할 수 있을 것이라고 판단되나, 횡성호 상류유역의 수질개선만 고려했기 때문에 호소 내 수질관리에 대한 후속 연구가 추가적으로 필요할 것으로 판단된다.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.1
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• pp.50-64
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• 2009

The freshwater lakes located at the fringe of urban cities are a habitat for diverse organisms. However, they are facing severe danger of environment deterioration and water pollution caused by reckless development of the area. In this study, an ecological management plan was suggested to promote the biodiversity through appointing management area based on the research and analysis data of flora and fauna as well as maintain biodiversity and harmonize utilization of freshwater lakes such as Duryang Reservoir at Sacheon, Gyeongsangnam-do. Base on the data of ecological research and analysis, this study conducted research on biotope assessment, wild life habitat assessment and presence of protected species. As a result, the ecosystem conservation area including multi-layer structured natural forests, waterside and wetland that are home to various species and the edge area with high habitat diversity were recognized as highly preservable regions. Management areas were ecologically disturbed region, highly polluted commercial district and damaged waterside caused by fishing. Proactive management must be implemented through vegetation management such as vegetation transition and shrub planting as well as establishing pollutant management system. The deterioration of waterside and forest vegetation of freshwater lake has a direct influence on biodiversity and water quality. Therefore, the conservation area and development area should be totally separated from each other, and the development area must be restored and managed strictly.

• Journal of Bio-Environment Control
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• v.2 no.2
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• pp.150-160
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• 1993

농업폐기물중 유기물이 상당부분인 축산폐기물(분뇨)는 하천의 수질악화, 호소의 부영양화 및 지하수오염 등의 자연환경오염의 주범중의 하나로 잘 알려져 있다. 그러나 축산폐기물은 그 처리방법에 따라서 환경오염을 줄일 뿐만 아니라, 적정공정을 통하여 퇴비화에 의한 자원화가 가능하다는 것은 이미 알려진 사실이다. 대체적으로 기초적이며 공통적인 부분에 관한 축산폐기물 처리시설 및 공정체계는 이미 제품화가 되어 가동중에 있고, 단지 지역적 특성이나 다양한 규모의 제약조건하에서 실행가능한 중소규모 시설에 관해서는 일련의 실험들을 통하여 개발ㆍ적응해 나가고 있는 추세라 할 수 있겠다.(중략)

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.154-154
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• 2023

수질모니터링은 수자원 보존과 공중 보건에 있어 매우 중요하다. 기후변화로 인한 이상강우와 산업화 등의 이유로 비점오염물질 및 오염원 배출량이 증가하여 하천과 호소에 영양염류가 증가하게 된다. 영얌염류의 증가로 하천에 부영양화 상태가 지속된다면 녹조발생 등으로 인해 생태계에 부정적 영향을 초래하게 된다. 또한 부영양화는 원수의 유기물량 증가로 인해 처리비용 증가, 이취미 문제 등 인간에게도 직접적인 문제를 유발한다. 특히 우리나라의 경우 하천 취수율이 높은 국가이며, 낙동강 중상류 지역에는 산업시설이 과도하게 밀집되어 있어 하천에 오염물질 유입이 되어 부영양화가 된다면 심각한 문제를 유발하게 된다. TN은 부영양화의 중요한 지표다. 우리나라의 TN 측정은 시료 채수 후 실험실에서 수질오염공정 시험기준에 따라 진행이 된다. 실험실 분석은 TN 농도를 분석하는 일반적인 방법이며, 정확한 검출 및 정량화를 목표로 한다. 하지만 이러한 방식은 정교한 장비를 갖춘 전문 실험실 및 전문 인력을 필요로 한다. 환경부에서 주요 하천에 수질측정망을 설치하여 수질현황에 대한 종합적인 조사를 통해 수질변화 추세를 파악하는 것이 가능하지만, 실시간 TN 농도를 감지하는데 매우 제한적이다. 현재 조사방식은 TN 농도 증가로 인한 문제에 대해 초기대응을 하기에는 한계가 있다. 최근 센서의 발전으로 다양한 항목을 신속하고 지속적으로 모니터링 할 수 있게 되었다. TN에 대한 직접적인 센서 모니터링은 불가능 하지만 여러 측정 항목이 TN과 상관관계가 있는 것이 여러 연구에서 입증되었다. 이러한 결과를 바탕으로 본 연구에서는 오염도가 높은 낙동강을 대상으로 TN 예측에 대한 기초 연구를 진행하였다. 과거 측정된 자료를 활용하여 센서로 측정 가능한 항목을 통해 TN 예측을 진행하며, 실제 활용을 위해 회귀식을 도출하고자 한다. 최근 환경부에서 실시간 수질 현황 및 오염도를 파악하기 위해 자동측정망 지점을 늘리는 추세인데, 본 연구의 결과를 활용한다면 실시간 TN 예측에 대한 기초자료 활용될 수 있을 것으로 판단된다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.587-597
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• 2023

We evaluated the eutrophication of Saemangeum Lake, which causes abnormal growth of algae, using the Carlson index. Eutrophication characteristics of Saemangeum Lake were analyzed. For the study, water quality surveys were conducted at 7 stations in Saemangeum Lake every month in 2021. The concentration of Chl.a was slightly higher in the Mankyeong water system in winter, and slightly higher in the Dongjin water system in spring and summer, but overall, except for some periods, the concentration was similar to or lower than the lake water quality environmental standard of class 3. COD showed water quality similar to or above the lake quality environmental standard of grade 4 in both the Mankyeong and Dongjin water systems in the summer and Autumn. TOC concentrations were within lake water quality standard 3 at all sites. Total phosphorus concentrations exceeded the lake water quality standard of Class 4 and were higher in January and August after rainfall. In the correlation analysis between water quality factors, the correlation of organic matter, total phosphorus, and total nitrogen to salinity was relatively high. This reflected the water quality characteristics of freshwater, brackish water, and seawater areas due to seawater inflow through the drainage gate and freshwater inflow through upstream rivers. According to the characteristics of eutrophication fluctuations in Saemangeum Lake by trophic state index, the indices of Chl.a, SD, and TN showed water quality in the early stage of eutrophication, while the TP index showed a severe eutrophication state. The magnitude of the eutrophication index among water quality components was TSI(TP) > TSI(TN) > TSI(SD) > TSI(CHL) in all water systems. Quadrant analysis of the deviation of TSI(CHL) from TSI(TP) and TSI(SD) on a two-dimensional plane showed that there was no limiting effect of total phosphorus on algal growth in all water systems. In addition, the factors af ecting light attenuation appeared to be dominated by small particulate matter from outside sources.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.396-406
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• 2011

To analyze between water quality and community structure of benthic macroinvertebrates, we selected four reservoirs (Lake Sayeon, Lake Daeam, Seonam reservoir and Lake Hoeya) in Ulsan-si and studied them from February 2010 to October 2010. The annual mean BOD (Biochemical Oxygen Demand) in the four lakes was $14.2mg\;L^{-1}$, and Seonam reservoir had the highest deviation in BOD. The maximum BOD for every lake was in February and their minimum in May, except for Lake Hoeya whose minimum was in July. The means of various nutrients were as follows: TN $0.051mg\;L^{-1}$, TP $0.100mg\;L^{-1}$, $NH_3-N\;0.606mg\;L^{-1}$, and $NO_3-N\;0.014mg\;L^{-1}$. The maximum TN was measured in June and the maximum and minimum TP were measured in March and in May respectively in the four lakes. Benthic macroinvertebrates were surveyed in April and October 2010. The number of benthic macroinvertebrates species was in the range of 16~36 and the average number of individuals were 58~208 inds. $m^{-2}$. Seonam reservoir, which has the highest mean TN ($0.082mg\;L^{-1}$) and $NO_3-N$($0.023mg\;L^{-1}$), had the largest number of species (36 species, 208 inds. $m^{-2}$). Pearson's correlation between the number of macro invertebrates species and TN was 0.962 (P<0.05), and between the species and $NO_3-N$ was 0.999 (P<0.05). These results show that the number of benthic macroinvertebrates species of the four lakes in Ulsan-si is significantly correlated with TN and $NO_3-N$.