• Journal of Korean Society of Rural Planning
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• v.19 no.4
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• pp.319-327
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• 2013

The objective of this research was to develop a relational database management system(RDBMS) to collect, manage and analyze data on agricultural non-point source(NPS) pollution. The system consists of the relational database for agricultural NPS data and data process modules. The data process modules were composed of four sub-modules for data input, management, analysis, and output. The data collected from the watershed of the upper Cheongmi stream and Geunsam-Ri were used in this study. The database was constructed using Apache Derby with meteorological, hydrological, water quality, and soil characteristics. Agricultural NPS-Data Management System(ANPS-DMS) was developed using Oracle Java. The system developed in this study can deal with a variety of agricultural NPS data and is expected to provide an appropriate data management tool for agricultural NPS studies.

• Journal of Korean Society on Water Environment
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• v.34 no.3
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• pp.328-338
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• 2018

The objective of this study was to evaluate the applicability of a HSPF (Hydrological Simulation Program-Fortran) model for runoff estimation in the Namgang dam watershed. Spatial data, such as watershed, stream, land use, and a digital elevation map, were used as input for the HSPF model, which was calibrated and validated using observed runoff data from 2004 to 2015 for three stations (Sancheong, Shinan, Changchon) in the study watershed. Parameters for runoff calibration were selected based on the user's manual and references, and parameter calibration was done by trial and error. The $R^2$ (determination coefficient), RMSE (root-mean-square error), NSE (Nash-Sutcliffe efficiency coefficient), and RMAE (relative mean absolute error) were used to evaluate the model's performance. Calibration and validation results showed that annual mean runoff was within a ${\pm}5%$ error in Sancheong and Shinan, whereas there was a14% error in Changchon. The model performance criteria for calibration and validation showed that $R^2$ ranged from 0.80 to 0.92, RMSE was 2.33 to 2.39 mm/day, NSE was 0.71 to 0.85, and RMAE was 0.37 to 0.57 mm/day for daily runoff. Visual inspection showed that the simulated daily flow, monthly flow, and flow exceedance graph agreed well with observations for the Sancheong and Shinan stations, whereas the simulated flow was higher than observed at the Changchon station.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.494-502
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• 2018

The purpose of this study was to understand distribution characteristics of organic matters through concentration of $BOD_5$, $COD_{Mn}$ and TOC in 31 streams in Han River region, and to establish the relationship among organic matter concentration, and discharge load and flow rate. Concentration of $BOD_5$ and TOC in 22 streams were above IV grade except 9, and the average 80.9 % of total organic matter (by TOC) accounted for dissolved organic type. Correlation among organic matter parameters were higher ($r^2$ > 0.78) and the relationship between TOC and $COD_{Mn}$ concentration was higher than $BOD_5$. Ratio of biodegradable organic matter/total organic matter in the 31 streams was estimated at 41.4 % with $BOD_5$ oxidation rate, and 78.0 % with $BOD_5/COD_{Mn}$ concentration ratio. Ratio of $NBOD/BOD_5$ concentration in four sites with $BOD_5/COD_{Mn}$ concentration ratio exceeding 1 ranged from 54.5 % ~ 79.3 %. Among 979 flow rate data measured at 31 streams, 87 % of measured data was below 0.1 cms and increased water pollution under low flow conditions. Correlation between $BOD_5$ concentration and $BOD_5$ discharge load in the watershed was low, and it was revealed that several streams have more $BOD_5$ delivery load than $BOD_5$ discharge load. Results suggest that many biodegradable forms of organic matter are being introduced into the stream from pollutant sources in the watershed.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.1005-1016
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• 2013

The objective of this study was to evaluate spatio-temporal water shortage distribution in the Sapgyo catchment considering both permitted and non-permitted water rights obtained from the total water right survey conducted in 2010. The results showed that the agricultural water accounted for 98% of the total water uses with 83% being the non-permitted agricultural water uses. During the 11-year (2001~2011) simulation period, water shortage was shown only in the upper Gokgyo stream sub-catchment with the highest water stress from April to May in 2009, particularly because of the large demand for rice cultivation associated with low precipitation. As water shortage was not expected to happen when the permitted water rights were not considered, it was concluded that a proper management of non-permitted water rights would be urgent.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.39-45
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• 2010

When the Juam multipurpose dam which is connected with existing large water supply facilities is finished, water environment is changed from stream to lake. The changed quality of water should be examined. In this study, the result of water quality forecasting is analysed and an effective management plan of water quality is presented. Tn this study, the WASPS model that is a dynamic water quality simulation model was selected to forecast the water quality. This model forecasts movement of change of pollutants. For an application of the model, the subject areas were divided into seventeen sub-areas by considering change temperature depending measuring points and on depth of water. Meteorological data collected by the meteorological observatory and data about quality measured by the Korea Water Resources Development Corporation were used for an operation of the model. As a result of quality examination through quality data and estimated pollutant loading, the water quality environment criterion was grade II and the nutritive condition was measured as meso-graphic grade. In this study, an effective management was planned to improve water quality by reducing pollution load. According to the result of examination, when more than 30% of BOD was reduced it was recorded that the environment standard of water quality was improved to the second grade.

• Spatial Information Research
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• v.17 no.3
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• pp.389-395
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• 2009

In spite of many numerical analysis of debris flow, a little information has been found out. In this paper the watershed is divided to apply rainfall runoff and to estimate debris flow integrating flow and soil article. We use the contour data to extract spatially distributed topographical information like stream channels and networks of sub-basins. A Quasi Digital Elevation Model (Q-DEM) is developed, integrated, and adopted to estimate runoff based on marked one. As a results, it has been found out that the debris flow was close to observed flow hydrograph. Because debris flow is finished in 30 second, it is important that we have to prepare its prior countermeasure to minimize the damage of debris flow. The GIS-linked model will provide effective information to plan river works for debris flow.

• Journal of the Korean association of regional geographers
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• v.14 no.2
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• pp.114-125
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• 2008

Colored dissolved organic matter(CDOM) is an important component of ocean color that can be used as an invaluable tool in water quality and ocean color studies. With the largest source of coastal CDOM appearing to be from freshwater discharge into the ocean, coastal predictive models will do much to refine our knowledge about major processes that control CDOM distributions in coastal waters and provide a better insight into the global carbon cycle. This study aims at developing a GIS-based watershed-scale predictive model of CDOM distributions in Neponset river watersheds that can be used to appraise our understanding of CDOM sources and distributions in coastal waters and predict the response of CDOM concentration to changes in land use patterns. Weighting factors are developed for CDOM freshwater sources after extensive groundtruthing from various landuse types in the watershed. This model makes use of a publicly available DEM(Digital elevation model) as the base data for analysis. Stream networks, discharge, and land use data are used from public repositories while sub- watershed delineation, pour-points, and land use parcels are generated using Spatial Analysis of ArcGIS 9.2 to estimate the CDOM loading from various sources to the lower tributaries of rivers. The Neponset Watershed in eastern Massachusetts is selected as the site for development of the model.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.71-88
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• 2005

This study has been monthly carried out to investigate the community structure and seasonal variations of Coleoptera from April to September, 2004 in Mt. Yeonyeop area, Gangwon-do, Korea. A total of 3053 individuals belonging to 358 species in 49 families have been collected in the studied area by light trap, pitfall trap and sweeping methods. The abundant families, based on the number of species, were Carabidae (50 species), Chrysomelidae (40 species) and Curculionidae (40 species). The number of species were highest at site 4, located in low altitude and contained stream. The number of individuals were highest at site 2, because many beetles were attracted by pitfall traps. The total number of species and individuals was highest in July. Nicrophorus (Nicrophorus) quadripunctatus (13.00%) was a dominant species and Synuchus (Synuchus) cycloderus (7.17%) was sub dominant species. Especially Damaster mirabilissimus mirabilissimus, a protected species by government, was collected in May.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.261-272
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• 2014

Over the last three decades, advances in AMS (Accelerator Mass Spectrometry) and Noble Gas Mass Spectrometer make various application of terrestrial cosmogenic nuclides (CNs) to wide range of earth surface sciences possible. Dating techniques can be divided into three sub-approaches: simple surface exposure dating, depth-profile dating, and burial dating, depending on the condition of targeted surfaces. In terms of Korean landscape view, CNs dating can be applied to fluvial and marine terrace, alluvial fan, tectonic landform (fault scarp and faulted surfaces), debris landforms such as rock fall, talus, block field and stream, lacustrine and marine wave-cut platform, cave deposits, Pliocene basin fill and archaeological sites. In addition, in terms of lithology, the previous limit to quartz-rich rocks such as granite and gneiss can be expanded to volcanic and carbonate rocks with the help of recent advances in CNs analysis in those rocks.

• Journal of Korean Society on Water Environment
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• v.37 no.2
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• pp.92-102
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• 2021

In this study, the distribution characteristics according to the type of BOD and the effect of nitrogenous oxygen demand (NOD) and algal oxygen demand on BOD in three streams (Bokhacheon, Byeongseongcheon, and Gulpocheon) were evaluated. Although the BOD and NOD concentrations demonstrated a difference in the three streams, the carbonaceous BOD(CBOD)/BOD ratio was 0.75 (p=0.053, one-way ANOVA), and there was no significant difference in the three streams (r2≥0.92, p<0.0001). The NOD concentration of the Bokhacheon with high NH3-N was 1.7±1.3 mg/L, which was the highest among the three streams and showed a significant correlation with BOD. Seasonal variations in NOD in the three streams did not show a significant correlation with changes in NH3-N concentration (r2<0.28, p≥0.1789), and there was no significant difference in NOD even though NH3-N concentration in Gulpocheon was about twice that of Byeongseongcheon (p=0.870, one way ANOVA). The particulate CBOD(PCBOD)/CBOD ratio of the three streams was 0.55~0.64, and about 60% of the biodegradable organic matter was present in the particulate form. When the Chl.a concentration in the stream was more than 7 ㎍/L, the PCBOD tended to increase with the Chl.a concentration (r2=0.61, p=0.003). In the three streams, particulate NOD accounted for 81% of NOD; however, despite the large variation in NH3-N concentration (0.075~3.182 mg/L), there was no significant difference in soluble NOD(SNOD) concentration that ranged from 0.1 to 0.3 mg/L. In this study, the low contribution rate of SNOD to NOD is considered as a result of the removal of nitrifying bacteria along with the particles during the filtration process.