• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.1
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• pp.22-31
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• 2001

The purpose of this study is to compare calculated pollutant loadings using pollutant load unit factors and vector type coverage, and expected mean concentration(EMC) and raster type of digital elevation model(DEM). This study is also focusing on comparison of the advantages and the disadvantages of the two methods, and seeking for a method of calculation of pollutant loadings using DEM. Estimation of pollutant inputs using pollutant load unit factors has limitations in identifying seasonal variations of pollutant loadings. Seasonal changes of runoffs should be considered in the calculation of pollutant loadings from catchments into reservoirs. Evaluation of pollutant inputs using runoff-coefficient and EMC can overcome these drawbacks. Proper EMC and runoff-coefficient values for the Koeup stream catchments of the Koheung estuarine lake were drawn from review of related papers. Arc/Info was employed to establish database of spatial and attribute data of point and non-point pollutant sources and characteristics of the catchments. ArcView was used to calculate point and non-point pollutant loadings. Pollutant loads estimated with either unit factors-coverages, i.e., pollutant load unit factors and vector coverages f point sources and land use, or EMC and digital elevation mode(DEM) were compared with stream monitoring loads. We have found that some differences were shown between monitoring results and estimated loads by Unit Factors-Coverage and EMC-DEM. Monthly variations of pollutant loads evaluated with EMC-DEM were similar to those with monitoring result. The method using EMC-DEM can calculate accumulated flows and pollutant loads and can be utilized to identify stream networks. A future research on correcting the difference between vector type stream using flow direction grid and digitalizing vector type should be conducted in order to obtain more exact calculation of pollutant loadings.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.1016-1027
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• 2010

The phosphorus contribution rate on water quality of North and South-Han River, and Gyungan-cheon by effluents from environmental fundamental facilities located in upstream basin of Paldang Lake were analyzed. QUALKO2 model was selected for the analysis of contrubution rate, and was constructed considering the location of the main point sources and all facilities in study area. The pollutant loading rates and arrival rates for each unit-watershed in study area were calculated for model operation. For the calibration and verification of model, 2006 water quality dataset from Ministry of Environment and the effluent loadings of the environmental fundamental facilities were used. Reliability Index (RI) method was used to estimate the validity of the results of calibration and verification. The phosphorous contribution rate(%) for each environmental fundamental facility were analyzed by excepting the effluent loading of the facility. The contribution rate was analyzed for each facility, facility groups separated by each main river and each unit-watershed. The main results of analysis for each facility are as follows; (i) the phosphorous contribution of B1 facility is 50%, which is the highest phosphorous contribution rate among those of nine facilities in the North-Han River Basin; (ii) the highest phosphorous contribution is 55.6% from J facility among eight facilities in the Gyungan Stream Basin; (iii) 40% from E treatment facility is the highest among those of twenty eight facilities in the South-Han River Basin.

• Water for future
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• v.20 no.4
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• pp.267-278
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• 1987

This study aims at the decision of geomorphologic instantaneous unit hydrograph(GIUH) model parameter fore the ungaged or the data deficiented Basin, to analyze rainfall runoff relation in river basin by applying queueing theory with geomorphologic factors.The concept of GIUH model is based upon the principle of queueing theory of rain drops which may follow many possible routes during rainfall period within watershed system to ist outlet. Overland flow and stream flow can be simulated, respectively, by linear reservoir and linear channel conceptual models. Basically, the model is a mon-lineal and time variant hydrologic system model. The techniques of applying are adopted subarea method and mean-value method, the watershed is divided according to its stream number and order. To prove it to be applicable, the GIUH model is applied to the Wi-Stream basin of Nak-Dong River(Basin area; 475.53$\textrm{km}^2$), southen part of Korea. The simulated and the observed direct runoff hydrographs are compared with the peak discharge, times to peak and coefficients of efficiency, respectively, and the results show quite satisfactory.Therefore, th GIUH model can be extensively applied for the runoff analysis in the ungaged and the data deficiented basin.

• Journal of Environmental Science International
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• v.26 no.4
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• pp.433-445
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• 2017

In recent years, the United States has used the Load Duration Curve (LDC) method to identify water pollution problems, considering the size of the pollutant load in the entire stream flow condition to effectively evaluate Total Maximum Daily Loads (TMDLs). A study on the improvement of the target water quality evaluation method was carried out by comparing evaluations of two consecutive years of water quality and LDC data for 41 unit watersheds (14 main streams and 27 tributaries). As a result, the achievement rate of the target water quality evaluation method, according to current regulations, was 68-93%, and that by the LDC method was 82-93%. Evaluating the target water quality using the LDC method results in a reduction in the administrative burden and the total amount of planning as compared to the current method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.4
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• pp.27-43
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• 1990

This study aimed at developing a generalized model on the estimation of the long - term run - off volume for practical purpose. During the research period of last 3 years( 1986-1988), 3 types of estimation model on the long - term run - off volume(Effective rainfall model, unit hydrograph model and barne's model for dry season) had been developed by the author. In this study, through regressional analysis between determinant factors (bi of effective rainfall model, ai of unit hydrograph model and Wi of barne's model) and catchment characteris- tics(catchment area, distance round the catchment area, massing degree coefficient, river - exte- nsion, river - slope, river - density, infiltration of Watershed) of 11 test case areas by multiple regressional method, a new methodology on the derivation of determinant factors from catchment characteristics in the watershed areas having no hydrological station was developed. Therefore, in the resulting step, estimation equations on run - off volume for practical purpose of which input facor is only rainfall were developed. In the next stage, the derived equations were applied on the Kang - and Namgye - river catchment areas for checking of their goodness. The test results were as follows ; 1. In Kang - river area, average relative estimation errors of 72 hydrographs and of continuous daily run - off volume for 245 days( 1/5/1982 - 31/12) were calculated as 6.09%, 9.58% respectively. 2. In Namgye - river area, average relative estimation errors of 65 hydrographs and of conti- nuous daily run - off volume for 2fl days(5/4/1980-31/12) were 5.68%, 10.5% respectively. In both cases, relative estimation error was averaged as 7.96%, and so, the methodology in this study might be hetter organized than Kaziyama's formula when comparing with the relative error of the latter, 24~54%. However, two case studies cannot be the base materials enough for the full generalization of the model. So, in the future studies, many test case studies of this model should he carries out in the various catchment areas for making its generalization.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.97-99
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• 2003

Lineament density maps can be used for the quantitative evaluation of relationship between lineaments and groundwater occurrence. There are several kinds of lineament density maps including lineament length density, lineament cross-points density, and lineament counts density maps. This paper reports the usefulness of the representative elementary area (REA) concept for lineament analysis. This concept refers to the area size of the unit circle to calculate the lineament density factors distributed within the circle: length, counts and cross-points counts. The circle is a unit circle that calculates the sum of the lineament length, lineament counts and the number of cross-points within it. The REA is needed to obtain the best representative lineament density map prior to the analysis of relation between lineaments and groundwater well yield or other groundwater characteristics. A basic lineament map for the Yongsangang-Seomjingang watershed of Korea, drawn from aerial black-and-white photographs of 1/20, 000 scale was used for demonstrating the concept. From this study, the conclusions were as follows: (1) the REA concept can be efficiently applied to the lineament density analysis and mapping, (2) for whole Yongsangang-Seomjingang watershed which has 6, 502 lineaments with an average lineament length of 3.3 km, the lower limits of each REA used for drawing the three density maps were about 1.77 $\textrm{km}^2$ (r=750 m) for lineament length density, 7.07 $\textrm{km}^2$ (r=1, 500 m) for lineament counts density, and 4.91 $\textrm{km}^2$ (r=1, 250 m) for lineament cross-points density, respectively, (3) the lineament densities are inversely proportional to the size of REA, and the REA can be calculated with this inversely linear regression model, (4) if the average lineament density values for the whole study area are known, the most accurate density maps can be drawn using the REAs obtained from each linear regression model, and (5) but critical attention should be paid to draw lineament counts density and lineament cross-points density maps because.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.569-575
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• 2015

The current Total Pollution Load Control (TPLC) sets the Target Water Quality (TWQ) by utilizing the delivery ratio, unit loads, and water quality modeling, it also allocates the watershed's permitted discharge load. Currently, common target pollutants of every unit watershed in TPLC are BOD and T-P. This study has reviewed the 1th and 2th of TWQ setting process for the Nakdong River 3th TWQ setting in Total Pollution Load Control (TPLC). As a result of review, 1th and 2th were divided into one management basin (mulgeum) for setting management goals. However, 3th was divided into six management basins (mulgeum, gnagjeong, geumho river, nam river, miryang river, end of nakdong river). The principle of management goal setting were to achieve the objective criteria of Medium Areas for the linkage of the water environment management policy. And Anti-Degredation (principle of preventing deterioration) were applied to the 3th TWQ. Also, additional indicators were considered in accordance with the reduction scenarios for the final management goals.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.557-568
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• 2013

In this study, Calculated the nonpoint sources(NPS) load per unit area about various rainy events in vineyard of Nakdong River basin. NPS monitoring and calculation for NPS load per unit area were estimated from 'Investigation method of precipitation discharge(National Institute of Environmental Research, 2007)'. The evaluation of applicability for NPS load per unit by compared with prior research data and Total Maximum Daily Load(TMDL) data. Five target areas were each $2000m^2$, $1800m^2$, $1943m^2$, $2484m^2$, $864m^2$ and located in Gyeongsangbukdo Gyeongju, Gyeongsangbukdo Sangju, Gyeongsangnamdo Hapcheon in Korea. Since fruits were the only crop on the target area, the characteristics of stormwater discharge at survey sites could be evaluated independently. A total of 115 rainfall events in the Orchard area during five years(2008-2012) was surveyed, and 38 of them became stormwater discharge. In the Nakdong River watershed, average of event mean concentrations(EMCs) in Orchard area for biochemical oxyzen demand(BOD), Chemical oxyzen demand(COD), total nitrogen(T-N), total phosphorus(T-P) were 2.0mg/L, 10.1mg/L, 3.195mg/L, 0.578mg/L, respectively. NPS load per unit area in Orchard area showed BOD : $2.0kg/km^2{\cdot}day$, COD : $10.2kg/km^2{\cdot}day$, T-N : $3.220kg/km^2{\cdot}day$, T-P : $0.606kg/km^2{\cdot}day$.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.3-13
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• 2006

Although the drought impacts are comparably not catastrophic, the results from the drought are fatal in various social and economical aspects. Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Soil moisture depletion directly resulted from rainfall shortage is highly related with drought, especially for crops and vegetations, therefore a drought can be evaluated using soil moisture conditions. In this study, SMI (Soil Moisture Index) was developed to measure a drought condition using soil moisture model and frequency analysis for return periods. Runs theory was applied to quantify the soil moisture depletions for the drought condition in terms of severity, magnitude and duration. In 1994, 1995, 2000, and 2001, Korea had experienced several severe droughts, so the SMI developed was applied to evaluate applicability in the mid-range hydrologic unit watershed scale. From the results, SMI demonstrated the drought conditions with a quite sensitive manner and can be used as an indicator to measure a drought condition.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.27-35
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• 2010

The characteristics of delivered nutrient loads were analyzed and the regression equations to estimate delivery ratios of nutrients (TN and TP) were developed using HSPF simulation results at six subwatersheds within the Bochung A unit watershed during 1998-2007. TN delivery ratio was higher than TP delivery ratio because significant amounts of TP was considered to be attached at soil as ${PO_4}^-$ during delivery process from discharged point of nutrient source to main stream. As a results of correlation analysis, factors related to geomorphic characteristics had not statistical correlation with TN and TP delivery ratios. TN loading rate from living and specific stream flow had statistical negative and positive correlation, respectively, with TN delivery ratio. TP loading rates from all sources and from land cover and specific stream flow had statistical negative, negative and positive correlation, respectively. The specific stream flow represents the most strong correlation with nutrient delivery ratios. The regression equations to estimate delivery ratios for TN and TP were developed by including statistical correlated factors and showed high efficiency of 0.98 and 0.95 of coefficient of determination for TN and TP, respectively.