• Water for future
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• v.26 no.3
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• pp.125-135
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• 1993

This study was conducted for two purposes. The first was the selection of the proper model for the urban runoff, and NPS(non-point source) loads and the second was the adjustment of the selected model through the calibration and the verification of the observed data on an urban drainage basin. The selected model for this study was the Storm Water Management Model(SWMM) developed and maintained by the US Environmental Protection Agency(EPA). In particular, the Runoff Block for the surface discharge and the Transport Block for the flow routing was used. The study basin is Youngdu basin, which is a typical developed urban drainage basin. The four rainfall events for the runoff and the two for the four NPS pollutants(SS, BOD, COD and TN) were used for the calibration and the estimation of the model parameters. This study performed the calibration with regard to the peak discharge, the time to peak discharge, the volume and the relative error for three items. It was shown that SWMM can successfully be used for the prediction of the runoff and the NPS pollutants discharge. The result of this study can be used as the basis for the analysis of the correlation between the runoff and the NPS pollutants discharges, and the analysis of the mass balance with the monthly and annual NPS loads in an urban drainage basin.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.183-190
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• 2009

Characterization of the analysis of forest vegetation, soil environmental conditions and water quality were performed from March 2003 to March 2007. The two basins were characterized by cultivated area (Kaesim reservoir) and mountain area (Jangchan reservoir), and divided into eleven small basins, where dynamics of pollutants, forest vegetation and soil environmental conditions were surveyed. The vegetation can be divided into 10 types by $Z\ddot{u}rich$-Montpellier school's method. Pearson coefficients between vegetation type and water quality were correlated with dissolved oxygen (DO) in the Quercus variabilis community at the 5% level and total phosphorus (TP) in the Larix leptolepis plantation at the 1% level. Especially total phosphorous and total nitrogen increased in small basins where the proportion of cultivated and residential area increased. The analysis of influences of pollutant discharge on water quality showed that pollutant charge was very low in forest land area ($Y_{T-P}$=-0.0017X+0.2215, r=0.16, $Y_{COD}$=- 0.0395X+8.5051 r=0.47). The soil types of western area were comparatively simple, but those of eastern area were complicated with regosols, red-yellow soils, lithosoles, etc. The pH, total solid (TS) and volatile substance (VS) of the forest and agricultural land soils collected in each site were 5.4~6.9, 75.8~80.2%, and 3.80%~5.80%, respectively. According to the analytical result of soil environmental conditions, heavy metal contents fell short to the mean value of natural conditions. Runoff amount (Y) and depth of topsoil (X) were negatively correlated, $Y_{ron}=-1.0088X_{top}+35.378$ (r=0.68). The correlation was much lower in up-stream but much higher in down-stream, because permeation into soil particle was larger on down-stream due to its more or less gentle slope. Pearson coefficients between soil pH and water pH were statistically significant at 1% level.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.217-224
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• 2005

This study was aimed to analyze the long-term fluctuation of water quality and phytoplankton dynamics of Paldang reservoir in Korea and to assess the relationship between algal bloom patterns and hydrological, limnological data. Diatoms in Paldang reservoir occurred continuously through the year. Blue- green algae occurred during the summer season (from June to Sept.), and the highest count was observed in July. Occurrence pattern of green algae was similar to that of blue-green algae. The rest of algae contained a lot of Cryptomonas spp. whose concentration was high from May to Aug. Dominant algal genera (>>7,000 cells $mL^{-1}$) in Paldang reservoir were Aulacoseira, Cyclotella, Microcystis, and Cryptomonas spp. Microcystis and Anabaena occurred during the summer season. Many different green algal genera were found in Paldang reservoir but their abundances were very low. There were some significant correlations (r>0.3, p<0.05) between algal taxa and water quality; diatoms and water temperature, TP:blue-green algae and water temperature, pH, DO saturation, COD, TP; green algae and water temperature, pH, DO saturation, COD, SS, TP. Furthermore, algal genera and water quality was significantly correlated (r>0.3, p<0.05) ; Aulacoseira and TN, TP; Anabaena and water temperature, DO saturation, COD, TP : Microcystisand water temperature, pH, DO saturation, TP; Coelastrum and COD, SS; Scenedesmus and water temperature, COD, TN, TP; Cryptomonas and DO saturation, TN. In Paldang reservoir, the water temperature had relatively big effect on blue-green algal bloom that was also dependant upon its hydrologic condition.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.895-903
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• 2007

As for the increasing demanding on the development of direct-ecological landfill monitoring methods, it is needed for critically defining the condition of landfills and their influence on the environment, quantifying the amount of enzymes and bacteria mainly concerned with biochemical reaction in the landfills. This study was thus conducted to understand the fates of contaminants in association with groundwater quality parameters. For the study, groundwater was seasonally sampled from four closed unsanitary landfills(i.e. Cheonan(C), Wonju(W), Nonsan(N), Pyeongtaek(P) sites) in which microbial diversity was simultaneously obtained by 16S rDNA methods. Subsequently, a number of primer sets were prepared for quantifying the specific gene of representative bacteria and the gene of encoding enzymes dominantly found in the landfills. The relationship between water quality parameters and gene quantification were compared based on correlation factors. Correlation between DSR(Sulfate reduction bacteria) gene and BOD(Biochemical Oxygen Demand) was greater than 0.8 while NSR(Nitrification bacteria-Nitrospira sp.) gene and nitrate were related more than 0.9. A stabilization indicator(BOD/COD) and MTOT(Methane Oxidation bacteria), MCR(Methyl coenzyme M reductase), Dde(Dechloromonas denitrificans) genes were correlated over 0.8, but ferric iron and Fli(Ferribacterium limineticm) gene were at the lowest of 0.7. For MTOT, it was at the highest related at 100% over BOD/COD. In addition, anaerobic genes(i.e., nirS-Nitrite reductase, MCR. Dde, DSR) and DO were also related more than 0.8, which showing anaerobic reactions generally dependant upon DO. As demonstrated in the study, molecular biological investigation and water quality parameters are highly co-linked, so that quantitative real-time PCR could be cooperatively used for assessing landfill stabilization in association with the conventional monitoring parameters.

• KCID journal
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• v.18 no.2
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• pp.15-24
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• 2011

This study was carried out to analyze characteristics of water quality and correlation among water quality parameters in Idong reservoir used for agricultural water. The pH and concentrations of DO, SS, BOD, COD, TP, Chl-a in Idong reservoir almost met the water quality standards for agricultural water, but TN concentration exceeded the water quality standards for agricultural water. All of water quality items had no significant difference between horizontal points at 95% confidence level and the Idong reservoir was possible to be treated as the single water body. As NIP ratio of the Idong reservoir is 52, TP is a limiting nutrient salt. As TN exceeds the water quality standards, it is required to preserve TP below current state to prevent water bloom by eutrophication. Therefore, reduction of phosphorus from the watershed is necessary for controlling the eutrophication of Idong reservoir.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1063-1068
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• 2010

최근 들어 지구온난화의 영향 등 기후변화에 따라 호우의 빈도와 강도가 증가하여 홍수피해가 확대되고 토사재해, 댐과 저수지의 퇴사 문제가 심각하게 대두되고 있다. 특히 농업용저수지의 경우 제체가 노후화되고 유입토사에 의한 퇴사는 심각한 수준에 있다. 또한 도심중심의 다양한 공사 등은 토지 이용과 피복을 변화시켜 많은 토사 유출의 원인이 되고 있다. 이렇게 노출된 토사는 탁수발생원이 되고, 토사와 부유물로 형성된 탁수환경은 수중의 태양복사에너지 전달을 방해하여 수중생태계의 먹이사슬과 저서생물의 서식환경에 악영향을 미치고 있다. 특히 농업용 저수지는 반폐쇄성 수역으로써 탁수환경에 노출되기 쉬우며, 수질회복에는 많은 노력과 비용이 소요된다. 또한 탁수환경의 변화는 시 공간적으로 발생하고 지속적으로 일어나기 때문에 탁수환경에 미치는 토사에 대한 연구는 우선적으로 시행되어야 한다. 이러한 토사 정보의 추출 및 분석에 RS기법의 활용은 증대되고 있으나 우리나라에서는 아직 연구가 미진하여, 이에 대한 기초연구가 시급한 실정이다. 본 연구는 2단계로 진행하였다. 먼저 1단계는 탁도계(2100P turbidimeter)를 이용하여 토사농도 변화에 따른 탁도를 측정하여 탁도 관계식을 추정하였다. 2단계는 분광복사계(LI-1800)를 이용하여 토사농도 변화에 따른 분광반사율을 측정하고, 얻어진 결과는 도함수와 적분의 수치해석 방법으로 토사농도를 측정할 수 있는 최적밴드를 구하였다. 다음으로 각 밴드간의 비를 계산하여 탁수환경을 측정할 수 있는 가장 적합한 밴드 조합식을 구하였다. 얻어진 밴드 조합식은 1단계에서 추정한 토사농도에 따른 탁도 관계식과의 상관관계를 분석하여 분광복사계를 이용한 탁도 관계식을 추정하였다. 그 결과, 6개의 탁도 관계식이 추정되었으며 결정계수 $R^2$는 0.67의 높은 상관성을 보였다.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.151-159
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• 1994

This study was conducted to investigate the $NO_3-N$ concentration, the relationship between $NO_3-N$ and other ions, and patterns of ions in ground water used as drinking water in Cheju Island. Samples were collected from 19 wells in the northwest region, near the district of poultry complex, and 9 wells in the northeast region. In the northwest region, $NO_3-N$ concentrations in D-14 and D-202 wells near the pig farming facilities were 10.95 and 13.1 mg/L, respectively, exceeding the standard concentration of drinking water. The concentration in D-65, D-35, and D-120 wells were slightly lower than the standard concentration. However, $NO_3-N$ concentrations in the wells in the northeast region were lower than 3mg/L. In wells in the northwest region, $NO_3-N$ concentrations were negatively correlated with pH and positively correlated with $Ca^{++}$, $Mg^{++}$, $Na^+$ $Cl^-$, $SO_4^{--}$, and $Cl^-/HCO_3^-$. However, in the northeast region, they were not related with pH and the ions. The chemical compositions in D-65, D-35, and D-41 wells showed higher concentrations of $Ca^{++}$, $Mg^{++}$, $Na^+$, $Cl^-$, $NO_3-N$ and $SO_4^{--}$ than the unpolluted D-42 well. These results suggest that ground water near the pig farming complex was polluted by pig farming waste in the northwest region.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.424-428
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• 2013

To identify risk factors for Legionella contamination, water quality variables routinely measured in examination of natural and city waters were meta-analyzed for significance of correlation to Legionella incidences. For evaluation of abundance of Escherichia coli as a risk factor, which is currently used as an indicator of Legionella contamination in an official guideline in Korea, odds ratio (OR) of above-cutoff total coliform counts for Legionella presence/absence was used as the effect size in the meta-analysis. The OR was estimated as 1.05 (0.36-3.12, 95% CI), and the probability of having identical odds reached 0.92. Also, ORs from individual studies showed significant heterogeneity (P=0.008), which contributed to 63% of total variance of the ORs. In the case of heterotrophic plate count (HPC), the OR for Legionella presence/absence was 2.72 (2.04-3.63) with highly significant deviation from identical odds (P<0.0001). ORs from different studies were seemingly homogeneous ($Q_{df=8}$=12.7, P=0.12). Turbidity and concentrations of chlorine, iron ion and cupper ion were other routine variables that could be considered as risk factors. However, statistical measures from different studies were not uniform enough to develop an appropriate effect size while the number of studies reporting the variables was also small (3-5). In conclusion, HPC appeared to be appropriate as indicator of Legionella contamination, rather than fecal bacteria contamination. HPC may imply abundance of habitats (amoebas and biofilms) of Legionella in water. This result warrants further studies for standardizing protocols and cutoff values to infer Legionella risks from HPC.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.395-406
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• 2002

The sixty natural springs and community wells used as a drinking water in the Daejeon area are mainly located at the parks and the natural green districts. The purpose of this study is to investigate the characteristics of water quality and the contamination of the springs and the wells, and to suggest the management strategy for the springs and wells. For this study, we undertook water quality data from Daejeon City. According to the statistic analysis of water quality data, unacceptable rate as a drinking water was about 28 percent in 1999 and 24.5 percent in 2000, respectively. Major unacceptable factor is coliform, and others are bacteria, yersinia, color, turbidity, Fe and F. The unacceptable rate shows a roughly positive relationship with precipitation, that is, it shows highest rate during a rainy season between June and September. The major contamination source is likely to be the excrement of wild animals around natural springs and wells. Most of springs are vulnerable to the contamination of coliform and bacteria because of short residence time and shallow circulation in subsurface environment. The water samples collected from 31 springs or wells show weak acidic pHs, the electrical conductivity ranging from 63 to 357 $\mu\textrm{S}$/cm, and the hydrochemical types of Na(Ca)-HC0$_3$ and Ca-HC0$_3$. The groundwater samples of low total dissolved solid(TDS) belong to Na(Ca)-HC0$_3$. type, and the groundwater of high total dissolved solid is shifted towards Ca-HC0$_3$ type in the chemical composition. These hydrochemical characteristics indicate that most natural springs is in the early stage of geochemical evolution. The natural springs should be closed during a rainy season, which shows a high contamination rate. We suggest that a protection barrier around the springs should be built to keep wild animals away from the springs.

• Journal of Wetlands Research
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• v.12 no.2
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• pp.67-73
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• 2010

This study was performed to figure out what would be effective to maintain good water quality in the retention pond which was badly polluted before. In order to keep the good water quality of the retention pond it is necessary to prevent outer non-point source pollutants from flowing into the pond. In this study, we proposed to use porous slag as a blockage of the inflow into the pond from external non-point sources. We experimented with porous slag nets to see how the water is effected. With the results of the experiments, we found out there is a close correlation($r^2=0.9765$) between contact time and the removal rate of phosphorus, therefore we can conclude that contact time affects removal rate greatly. Synthetic wastewater, activated sludge effluent, and sewage were passed through a porous slag packed bed, both phosphorus and the suspended solid in water were removed highly. With the results of these tests, we proposed to set up a porous slag packed bed inside of the retention pond and revetment to prevent external non-point source pollutants flowing into the retention pond.