• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.15-33
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• 2017

Based on the existing pollutant emissin standards which are armed at the pollutant concentration of each pollution source, government formulated and implemented new management system of total water pollutant emission. By virtue of this new management system, pollution loading amount of individual watershed could be controlled, which achieved the requirement of water quality management such as TP and BOD. In initiate stage of it's implement, BOD was selected as object of water quality management, While it's necessary to consider the continuity of water quality data and established pollutant management laws and policy. During the ongoing management, TP management was added into the system while simply BOD management was not enough. However, the frequency of algae bloom in Han-river showed a trend of same, even though TP was treated as additional control target. Therefore, this paper will analyze different water quality parameters and characteristic of water quality, so that this study can be provide as reference for watershed management of water quality, by which the applicable management period and target pollutant can be selected in the future.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.369-376
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• 2007

This study was conducted to evaluate water quality in coastal sea of Kunsan using multivariate analysis. The analysis data in Coastal Sea of Kunsan use of surveyed data by the NFRDI from April 2000 to November 2002. Twelve water Quality parameter were determined on each sample. The results was summarized as follow ; Water quality in coastal sea of Kunsan could be explained up to 62.782% by four factors which were included in loading of nitrogen-nutrients by Keum river(24.688%), suspended solids variation (12.180%), seasonal climate variation (18.367%) and variation of DIP (10.546%). To analyze spatially and monthly variation by factor score, it was divided by inner area and outer area spatially, and spring and summer monthly. The result of time series analysis by factor score, inner area of Kunsan coastal sea(St.1 and St. 2) was the most affected by nitrogen-nutrient and suspended solids due to runoff by Keum river. It could be suggested from these results that it is important to reduce tile pollution loads from Kuem river for the control of the water quality in coastal sea of Kunsan.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.957-968
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• 2021

To improve the data on reliability of the onshore fish farm water quality monitoring system and operate the system efficiently, the water quality data of the onshore seawater fish farms which are progressing test operation, and the marine environmental information network(Wando tidal station) were compared and analyzed. Furthermore, data validation, data range filters, and data displacement checks were applied to analyze the data in a way that eliminates the data errors in water quality monitoring systems and increases the reliability of measurement data.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.11-18
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• 2005

When it is raining or snowing, floating debris flows into a lake and raises its turbidity. High level of turbidity in the lake often causes eutrophication, which pollutes the water. In order to collect and present some essential information for effective management plan for water quality, we carried out our research at the watershed of Mandae-cheon located at the upstream of Soyang Lake. We examined water quality at the time of rainfall or snowfall to analyze the changes in the amount of suspend soils(SS) in the lake.

• Journal of Industrial Technology
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• v.30 no.B
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• pp.125-135
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• 2010

The influences on water quality of each river by effluents from environmental facilities $located^{*}$ in 14 unit watersheds of North- and South-Han River, and Gyungan-cheon were analyzed. Also, the water quality modeling for study area was carried out to analyze the improvement effect of water quality by the strengthening of T-P effluent standard of environmental facilities. For the calibration and verification of model, water quality data and effluent loading calculated for 2006 were used. Data of low water period were used for calibration, and normal water period for verification. The results of calibration and verification were well matched with the real water quality dataset of revers. Also, the validity of the results were estimated using RI (Reliability Index) method. When the T-P effluent standards for environmental facilities were strengthened, T-P concentrations were predicted to improve from $0.025mg/{\ell}$ to $0.023mg/{\ell}$ in the outlet location of North-Han River, from $0.056mg/{\ell}$ to $0.040mg/{\ell}$ for South-Han River,and from $0.233mg/{\ell}$ to $0.146mg/{\ell}$ for Gyungan-cheon. Also, the T-P concentrations of tributaries including Jojong-cheon, Dal-cheong, Sumgang, Chungmi-cheon, Bokha-cheon, Heuk-cheon, and Wonju-cheon were predicted to improve from $0.063mg/{\ell}$ to $0.010mg/{\ell}$, from $0.091mg/{\ell}$ to $0.053mg/{\ell}$, from $0.199mg/{\ell}$ to $0.100mg/{\ell}$, from $0.168mg/{\ell}$ to $0.148mg/{\ell}$, from $0.186mg/{\ell}$ to $0.105mg/{\ell}$, from $0.019mg/{\ell}$ to $0.013mg/{\ell}$, and from $0.822mg/{\ell}$ to $0.236mg/{\ell}$, respectively.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.309-317
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• 2002

In this study, water protection reservoir is selected as the target which is located at the estuary of Taehwa river to analyze and examine the effects of hydraulic structure on river environment. This study examined the water quality variation characteristics among many effects of hydraulic structure on river environment before and after removal of the sediment protection reservoir when low flow is yielded. This study aims at the definition of factors which cause the change of ecological environment of river due to the effects of the sediment protection reservoir, and the proposal of the direction of environmental friendly river space development through the comparison of stream variation conditions(depth, velocity, and etc.) and riverbed variation characteristics with ecological depth condition of Taehwa-river's channel for each representative species of fish and examination those. Firstly, from the examination result of water quality when low flow is yielded before and after removal of the sediment protection reservoir for problems about water quality of river due to flow amount decrease in river, it is found that DO decreases about 0.78~0.86ppm at the lower stream of Myeongchon-gyo, and BOD decreases about 0.06~0.24ppm from right upper stream to the direction of estuary when the sediment protection reservoir is removed. It is known from the above that there is some improvement of water quality from the lower stream of Taehwa-gyo to the estuary in case of removal the sediment protection reservoir. Nextly, it is thought that the effects on ecosystem due to water depth and draw down in channel is not serious on the basis of the examination of water quality analysis result according to removal of sediment protection reservoir and hydraulic depths for reservation of ecosystem, these are 10~40cm for breeding season, 10~50cm for fry period, and 10~100cm for adult period of the representative species of fish in Korea.

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.101-110
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• 1999

This research was investigated to check characteristics of stream water quality at four points to analyze the characteristics of stream water in the northeastern part of Puk'ansan National Park during a period of July to November, 1998. The results are as follows. The level of average pH(6.56) and dissolved oxygen($10.22mg/{\ell}$) in the stream water quality on northeastern area in Puk'ansan National Park were at the level of the first class in the quality of river water quality standard. Also, the water in these streams was soft and equilibrated the ration and anion. Electrical conductivity in the stream water was correlated with total amount of ion and number of visitors, but conversely correlated with pH. And the number of visitors influenced stream water quality pollution. The multiple regression equations for electrical conductivity were well explained by pH, Zn and $Mg^{2+}$ statistically.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.761-770
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• 2013

This study was carried out to forecast the flow rate and water quality at the inlet of the Saemangeum bay in Korea using the SWMM(Storm Water Management Model) and the WASP(Water Analysis Simulation Program), and to analyze the impacts of pollutant loading from non-point source on the water quality of the bay. The calibration and validation of flow rate and water quality were performed using those from two monitoring points in the Mankyeong river administrated by Korean Ministry of Environment as part of the national water quality monitoring network. When the river flow rate was calibrated and validated using the rainfall intensities during 2011-2012, $R^2$ (i.e., coefficient of determination) was ranged from 0.91 to 0.96. For water qualities, it was shown that $R^2$ of BOD(Biochemical Oxygen Demand) was ranged from 0.56 to 0.86, and $R^2$ of T-N(Total Nitrogen) was from 0.64 to 0.75, and $R^2$ of T-P(Total Phosphorus) was from 0.67 to 0.89. The integrated modeling system showed significant advances in the accuracy to estimate the water quality. Finally, further simulations showed that annual average flow of the river running into the bay was estimated to be $1.439{\times}10^9m^3/year$. The discharged load of BOD, T-N, and T-P into the bay were anticipated to be 618.7 ton/year, 331.5 ton/year, and 40.4 ton/year, respectively.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.801-813
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• 2023

Recently, as studies about Artificial Neural Network (ANN) are actively progressing, studies for predicting water quality of rivers using ANN are being conducted. However, it is difficult to analyze the operation process inside ANN, because ANN is form of Black-box. Although eXplainable Artificial Intelligence (XAI) is used to analyze the computational process of ANN, research using XAI technology in the field of water resources is insufficient. This study analyzed Multi Layer Perceptron (MLP) to predict Water Temperature (WT), Dissolved Oxygen (DO), hydrogen ion concentration (pH) and Chlorophyll-a (Chl-a) at the Dasan water quality observatory in the Nakdong river using Layer-wise Relevance Propagation (LRP) among XAI technologies. The MLP that learned water quality was analyzed using LRP to select the optimal input data to predict water quality, and the prediction results of the MLP learned using the optimal input data were analyzed. As a result of selecting the optimal input data using LRP, the prediction accuracy of MLP, which learned the input data except daily precipitation in the surrounding area, was the highest. Looking at the analysis of MLP's DO prediction results, it was analyzed that the pH and DO a had large influence at the highest point, and the effect of WT was large at the lowest point.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.101-112
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• 2007

This study has used RMA2 model and RMA4 model, which are depth-averaged two-dimensional flow and water-quality prediction models, to analyze the variation of the water-quality by the gates operation in the Seonakdong River. Sensitivity analysis is performed to get the Manning coefficient and the coefficient of eddy viscosity for RMA2 model, and to get the diffusion coefficient for RMA4 model. Since the numerical simulation using RMA2 and RMA4 models did not consider tributary pollutant load except for that of Joman River, it could make a little difference from the natural phenomenon. Nevertheless, the numerical simulation shows that the discharge of $30m^3/s$, which is the continuous inflow from the Daedong-gate, can make it possible to achieve the target water-quality (BOD 4.3mg/L) of Nakbon-N watershed about 10 days later if the Daejeo-gate could remain opened in connection with the Noksan-gate operation.