• 한국물환경학회지
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• 제28권5호
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• pp.693-703
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• 2012

Load Duration Curve(LDC) is a useful tool for analyzing water quality characteristics under various stream flow conditions. This study investigated the methods to identify impaired waterbodies in the assessment of water quality goal attainment by using LDC for the management of Total Maximum Daily Loads (TMDLs). Three methods were proposed. Non-typical regime exclusion method is a method to exclude water quality observations in the non-typical extreme flow conditions in order to minimize the influence of non-ordinary water quality. Flow regime weighted average method is a method to calculate weighted mean water quality instead of arithmetic mean in order to consider water characteristics properly on stream flow regime in addition to the effect of Non-typical regime exclusion method. Load exceeded interval comparison method is a method to compare the intervals between the attained and non-attained load duration periods on the LDC. The assessment of water quality goal attainment can be performed more reasonably and precisely considering water quality variations on stream flow conditions by applying these proposed methods.

• 한국수자원학회논문집
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• 제35권2호
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• pp.149-159
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• 2002

삽교호유역에 위치한 19개 수질관측지점에서 측정된 월별수질자료를 이용하여 수질관측지점을 2개에서 7개의 수질특성으로 분류하였으며, 그에 따른 수질요인분석을 실시하였다. 군집분석결과 삽교호유역의 각 하천은 개개의 수질특성을 보이고 있으며, 삽교호, 삽효천, 무한천 및 곡교천의 4개 그룹으로 나눌 수가 있었다. 수질분석결과에 의하면 삽교호에서는 부유물질의 농도가 다른 하천보다 높았는데 이는 하천으로부터 유입되는 풍부한 영양염에 의한 식물플랑크톤의 생물량 증가에 따른 것으로 사료된다. 또한 곡교천의 수질은 다른 하천에 비해 생화학적산소요구량은 3.5∼4.8배, 화학적산소요구량은 1.7∼2.5배 높았으며, 전반적으로 삽교호 유역의 수질은 부영양상태를 훨씬 초과하였다. 요인분석결과 삽교천과 무한천은 농경지와 주거지에 의한 수질요인이 지배적이었고, 곡교천은 천안도시지역으로부터 유입되는 과다한 유기물유입과 상류에 위치한 하수처리장의 영향을 복합적으로 받고 있는 것으로 사료된다. 삽교호의 수질은 삽교천과 무한천및 곡교천에서 높은 부하를 보인 인자가 주된 오염요인으로 나타났다.

• 한국환경과학회지
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• 제31권5호
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• pp.431-445
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• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.

• 한국물환경학회지
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• 제22권5호
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• 한국물환경학회지
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• 제23권5호
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• pp.731-739
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• 2007

In this study, water quality monitoring focused on TOC was performed at 5 points in Mihocheon (Stream) from January to December 2006. And 10 parameters (water temperature, pH, DO, EC, turbidity, SS, BOD, $PO_4-P$, TOC, TN) were monitored every month for one year. According to this study, TOC increased towards the lower stream (#4~#5). Correlation coefficients between TOC and DO, EC, turbidity, SS, BOD, $PO_4-P$, TN were -0.126, 0.351, 0.320, 0.286, 0.711, 0.525, 0.666. TOC was highly related to BOD. As a result of linear regression analysis, regression equation between BOD and TOC was BOD=0.58TOC+1.90 ($R^2=0.506$). In Mihocheon (Stream), BOD/TOC ratio decreased towards the lower stream. This results show decrease of ratio of biodegradable organic material to total organic pollutants towards the lower stream. This study is significant since it has revealed the potential value of TOC as organic material indicator for inquiry of water quality characteristics in the natural water system.

• 한국농공학회논문집
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• 제63권6호
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• pp.89-100
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• 2021

The conservation of stream habitats has been gaining more public attention and fish habitat suitability index (HSI) is an important measure for ecological stream habitat assessment. The fish habitat preference is affected not only by physical stream conditions but also by water quality of which HSI was not available due to the lack of field data. The purpose of this study is to estimate the HSI of Zacco platypus for water quality parameters of water temperature, dissolved oxygen (DO), and biochemical oxygen demand (BOD) using the water environment monitoring data provided by the Ministry of Environment (ME). Fish population data merged with water quality were constructed by spatio-temporal matching of nationwide water quality monitoring data with bio-monitoring data of the ME. Two types of the HSI were calculated by the Instream Flow and Aquatic Systems Group (IFASG) method and probability distribution (Weibull) fitting for the four major river basins. Both the HSIs by the IFASG and Weibull fitting appeared to represent the overall distribution and magnitude of fish population and this can be used in stream fish habitat evaluation considering water quality.

• 한국농공학회지
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• 제45권7호
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• pp.49-56
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• 2003

Nonpoint source pollutant loading from watershed may cause a problem to the water quality of the reservoir and stream. The characteristics of stream flow and water quality were monitored to investigate the runoff loading of the Namdae-cheon watershed from May in 1999 to October in 2003. Stage-discharge rating curve at the stream gauging site was established, and annual stream runoff of the study watershed was estimated as 499.4∼1,330.8mm during four years. The concentrations of total-nitrogen and total-phosphorus of stream water quality ranged from 0.76 to 6.95mg/L and from 0.0010 to 0.2276 mg/L, respectively, where T-N was generally higher than the water quality standard 1.0 mg/L for agricultural water use. The loads by unit generation of pollutant mass with respect to population, livestock, land use in this watershed were calculated. The runoff pollutant loadings by concentrations of total-N and total-P were estimated during study period, where the annual runoff loading of total-P was much less than the load by pollutant mass unit generation. The relations between stream discharge and water quality were analysed, and there was a high correlation for total-N but low for total-P. These results will be used to develop the monitoring techniques and water quality management system of agricultural watershed.

• 한국물환경학회지
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• 제29권3호
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• pp.428-437
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• 2013

Physico-chemical water quality parameters and the phytoplankton communities from 12 sites in Oship-stream, Songchunstream, and Namdae-stream, located Gyeongsangbukdo Uljin-gun, Yeongdeok-gun, and Pyeonghae-eup respectively, were investigated from April 2009 to February 2010. Oship-stream, which is an open estuary, was easily affected by ocean current compared to that of Songchun-stream and Namdae-stream. OS3 and OS4 conductivity was higher with a season average of 3,397 ${\mu}s/cm$. The streams were mesotrophic to hypertrophic. Biological oxygen demand (BOD) was about 3mg/L, which was level 2 on the water quality ratings, but a concentration of 5mg/L in April 2009 indicated increased pollution due to drought. A total of 118, 117, and 124 phytoplankton taxa were found in Oship-stream, Songchun-stream, and Namdae-stream, respectively. The apparent dominant species in the polluted waters included Cryptomonas ovata, Fragilaria construens var. venter, Oscillatoria limnetica, O. limosa, and Phormidium tenue. All of Oship-stream, SC2 and SC4 of Songchun-stream, and ND3 of Namdae-stream were eutrophic as a result of standing crop analysis. BOD was highly correlated with chlorophyll-a content(r=0.52). Phosphorus concentration and proliferation of phytoplankton were thought to most affect BOD concentration in all three streams.

• 대한공간정보학회지
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• 제16권1호
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• pp.13-21
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• 2008

본 논문에서는 금강수계의 미호천을 대상으로 GIS를 이용, 2010년을 대상으로 장래수질을 예측하였다. 오염총량관리 기본계획에서 제시된 자료를 기반으로 미호천으로 유입되는 지류별 수계에 대하여 재계산하여 각 수계별 오염부하량을 산정하였으며 이들 정보를 활용하여 지류별 농도를 계산한 다음 미호천의 수질모의를 실시하였다. 수질모의는 대표적인 하천수질 모형인 Qual2E 모형을 사용해서 BOD, TN, TP 등의 대표적인 수질인자에 대한 모의를 실시 하였다. 수계별 오염부하량을 산정한 결과 도시지역을 포함한 무심천 및 보청천의 부하량이 높게 나타남을 알 수 있었고 미호천 전체 수질은 청주 하수처리장의 영향을 직접적으로 받는 것으로 나타났다. 대상유역에서의 효율적 수질관리와 오염총량제에서 제시한 목표수질을 달성하기 위해서는 하수처리장의 고도처리화가 먼저 달성되어야 함을 알 수 있었고, 그 외에도 무심천으로 공급되는 농업용수의 유량을 증가시켜 이를 수질희석의 용도로 사용하는 방안에 대해서 모의를 실시함으로써 수질기준을 만족할 수 있는 적정유량을 산정하여 제시하였다.

• 한국물환경학회지
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• 제22권2호
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• pp.238-243
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• 2006

In order to improve the water quality of stream water, the facilities equipped with rope media filter have been examined as a part of national projects. This work may provide design and operating parameters from 2 years monitoring for 2 streams. Depending on the characteristics of streams, the flow rate into the facilities were shown different, where K stream was almost the same and D stream was less than 25% of design flow rate. Although the clogging of filter media was not observed during the operation, the removal of accumulated sludges was required for the stable operation. The removal efficiencies of BOD, SS, T-N and T-P for D stream were 60.5%, 80.1%, 25.2% and 36.2%, respectively. The most important factor for the construction of stream water purification facilities was recommended for the selection of proper sites.