• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.87-95
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• 2021

The Doam Lake Watershed is one of Gangwon-do's non-point source management areas. This area has a lot of snowfall in winter, and it is expected that there will be a lot of soil erosion in early spring due to snow melting. In this study, snow melting was monitored in the Doam Lake watershed from February to 3, 2020. It was conducted to analyze the water quality changes by calculating the concentration of non-point source pollution caused by snowmelt, and to compare the concentration of water quality during snowmelt event with rainfall and non-rainfall event. As a result of water quality analysis, Event Mean Concentration (EMC) at the first monitoring was SS 33.9 mg/L, TP 0.13 mg/L, TN 4.33 mg/L, BOD 1.35 mg/L, TOC 1.84 mg/L. At the second monitoring, EMC were SS 81.3 mg/L, TP 0.15 mg/L, TN 3.12 mg/L, BOD 1.32 mg/L, TOC 3.46 mg/L. In parameter except SS, it showed good water quality. It is necessary to establish management measures through continuous monitoring.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.700-706
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• 2010

Along the 4 major rivers in korea, there are automatic water quality monitoring (AWQM) stations to immediately respond to any pollution incident. Real-time data (temperature, DO, pH, EC and TOC) collected at each station were statistically treated to exclude outliers and keep valid data using Dixon's test and Discordance test. These applied methods were compared in terms of the number of the outliers sorted out. There was no significant difference between these methods. On the other hand, more outliers were sorted out from EC and TOC data, comparing with other water quality items. EC data did not show partly any variation for a long time at H station. If measured signal does not exceed ${\pm}0.001mS/cm$ from the sectional mean, the signal should be treated as normal data. Therefore, another routine was added to the data screening system, some data which were removed as outlier were restored.

• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.9-19
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• 2024

As using public monitoring data, analysing a trends of water quality change, establishing a criteria to determine abnormal status and constructing a regression model that can predict Chlorophyll-a, an indicator of eutrophication, was studied. Accordingly, the three freshwater lakes were selected, approximately 20 years of water quality monitoring data were analyzed for periodic changes in water quality each year using regression analysis, and a method for determining abnormalities was presented by the standard deviation at confidence level 95%. By calculating the temporal change rate of Chlorophyll-a from irregular observed data, analyzing correlations between the rate and other water quality items, and constructing regression models, a method to predict changes in Chlorophyll-a was presented. The results of this study are expected to contribute to freshwater lake water quality management as an approximate water quality prediction method using the statistical model.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.373-381
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• 2012

An automatic flow and water quality monitoring system was applied to estimate pollutant loads to an urban stream during storm events in DTV (Daeduk Techno Valley), Daejeon, Korea. The monitoring system consists of rainfall gage, ultrasonic water level meter, water quality sensors for DO, temperature, pH, conductivity, turbidity and automatic water sampler for further laboratory analysis. All data are transmitted through on-line system and the monitoring system is designed to be controlled manually in the field and remotely from laboratory computer. Flow rates were verified with field measurements during storm events and showed good agreements. Automatic sampler was used to collect real time samples and analyzed for BOD, COD, TN, TP, SS and other pollutant concentrations in the laboratory. SWMM (Storm Water Management Model) urban watershed model was applied and calibrated using the observed flow and water quality data for the study area. While flow modeling results showed good agreement for all events, water quality modeling results showed variable levels of agreement. These results indicate that current options in the SWMM model to predict pollutant build up and wash-off effects are not sufficient to satisfy modeling of all the rainfall events under study and thus need further modification. This study showed the automatic monitoring system can be used to provide data to assist further refinement of modeling accuracy. This automatic stormwater monitoring and modeling system can be used to develop basin scale water quality management strategies of urban streams in storm events.

• Journal of Environmental Science International
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• v.23 no.4
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• pp.715-722
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• 2014

Effects of coagulation types on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Nakdong River water were used and alum and ferric chloride were used as coagulants. The aim of this study is to compare the coagulation characteristics of alum and ferric chloride by a photometric dispersion analyzer (PDA). Floc growing rates ($R_v$) in three different water temperatures ($4^{\circ}C$, $16^{\circ}C$ and $30^{\circ}C$) and coagulants doses (0.15 mM, 0.20 mM and 0.25 mM as Al, Fe) were measured. The floc growing rate ($R_v$) by alum was 1.8~2.8 times higher than that of ferric chloride during rapid mixing period, however, for 0.15 mM~0.25 mM coagulant doses the floc growing rate ($R_v$) by ferric chloride was 1.1~2.3 times higher than that of alum in the slow mixing period at $16^{\circ}C$ water temperature. Reasonable coagulant doses of alum and ferric chloride for turbidity removal were 0.1 mM (as Al) and 0.2 mM (as Fe), respectively, and the removal efficiency of those coagulant doses showed 94% for alum and 97% for ferric chloride. The appropriate coagulant dose of alum and ferric chloride for removing dissolved organic carbon (DOC) showed about 0.3 mM (as Al, Fe) and at this dosage, DOC removal efficiencies were 36% and 44%, and ferric chloride was superior to the alum for removal of the DOC in water.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.137-144
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• 2015

The purpose of this study is to develop an warning system to detect real-time water quality abnormality using a multivariate statistical approach. In this study, we applied principal component analysis among multivariate data analyses which was used for the correlation between water quality parameters considering the real-time algorithm to determine abnormality in water quality. We applied our approach to real field data and showed the utilization of algorithm for the real-time monitoring to find water quality abnormality. In addition, our approach with Korea Meterological Adminstration database identified heavy rain data due to climate change is one of the most important factors to explain water quality abnormality.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.05a
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• pp.28-44
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• 1993

Remediation actions in uncontrolled landfill site should be conducted after the investigation of contamination status and potential health risk or damage. Based on the above, proper control measures should be established and operated. Also continuous monitoring should be followed. In this study, the status of ground water contamination around Nanji Landfill Site was investigated. Monitoring wells were installed around the landfill and ground water was sampled once a month and analyzed. Water quality of each monitoring well was different depending on the horizontal and vertical distance from the landfill, and the seasonal leachate characteristics were not significantly changed because percolating water stayed long time in the deep waste layer. It was predicted that major multivalent cations were mainly precipitated as metal carbonate form, and chemical mass balances (CMBs) could be applied for the apportionment of leachate contamination to ground water quality of surrounding areas of Nanji Landfill. Parameters required to estimate pollutant flux to the receptor near landfill were listed and discussion to get these parameters was made. Finally, based on the above data, control measures of ground water contamination were suggested and discussed.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.13-19
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• 2013

The Chongok karst cave which is located in Donghae-city, has high tourist and educational value due to existence of many doline(sink hole). Whereas this cave is easy to approach for the tourists, because this cave is located near the downtown, a high environmental riskiness such as sewage flowing has been also involved. In study, we observed the variation of water quality with long-term monitoring and investigated the possibility of existence of impact factor to water eco-system and determined the proper long-term monitoring factor among many monitoring criteria. The groundwater quality was maintained in the range of about $14^{\circ}C$ in temperature, over 10mg/l in dissolved oxygen and 7-8 in pH, so the impact factor in water eco-system was not observed. The guide line to make sure of tourist safety was determined to 60mm/d as daily rainfall. The conductivity was suggested to main factor for long-term monitoring main factor and pH/turbidity was suitable for the supplementary factor. For the seasonal variation monitoring, ORP was recommended.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.88-96
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• 1999

This research was planned to propose some suggestions on the management of stream water quality in the closed valley areas of the Puk'ansan National Park during July 1998 to June 1999. A closed valley area should designate whole valley area. Stream water quality monitoring should include investigation on cations ($Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$), anions ($Cl^-$, $SO{_4}^{2-}$) and suspended solids. A counterplan for stream water preservation and its practical application should be considered before closing a valley area. Also, the results of stream water quality in the closed valley areas in the National Park should be informed to the public. Discharged water from private areas such as a Buddhist temple, shelter, resting place, shopping center, etc. in the National Park should be checked and cleaned. We need to establish regulations on the utilization of stream side area in the park, and trails near the closed valley should also be included in the areas.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.796-801
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• 2010

Water quality index (WQI) can be a great tool that allows experts to translate large amount of complex water quality data into a format more easily understood by the public and policy makers. Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) can be calculated with the three factors (Scope: $F_1$, Frequency: $F_2$, Amplitude: $F_3$). After all, the WQI for a specific site is produced as a number between 0 to 100; the scale is also divided into five categories, i.e., Excellent, Good, Fair, Marginal and Poor. The WQI was found to be highly related to Chl-a, pH, temperature among the collected items. When the more input parameters were used, the range of variation generally became smaller. $F_3$ among the factors of WQI was influenced by algae. It showed a similar variation tendency between WQI and algal bloom in 2008.