• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.598-607
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• 2010

One of constraints in the application of unit-load method to estimate non-point pollution loads in the total water pollutant load management system (TWPLMS) is the limited numbers of applicable unit-loads. Since only 7 unit-loads are currently available for total 28 land-use categories in the national land register data, each unit-loads inevitably have to represent several land-use categories regardless of their actual land coverage characteristics. As a way to minimize the problem, this study suggested a nested application of the available unit-loads based on the analysis of high resolution aerial images taken in the Kyeongan watershed. Statistical analysis of three selected land-use categories such as school, apartment complex, and golf course showed that there exit significant (95% confidence level) relationships between the registered land-uses and actual land coverages. The school and apartment complex currently considered as 100% ground have only 65% and 80% of ground characteristics, respectively. Golf course, which is considered as 100% pasture, has about 5% of ground area. This indicates that the unit-load method using in TWPLMS can give over estimated non-point pollutant loads for the school and apartment complex (19.8~54.4%) but under estimation for the golf course (80.9%).

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.89-100
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• 2006

In order to estimate delivered nutrients load from non-point sources in the Gap stream watershed in Daejeon, a distributed watershed model SWAT2000 was used so that it could predict the impact of land management practices on water, sediments and chemicals yields in large complex watersheds with varing soils, land uses and management condition over long period of time. The SWAT2000 was applied to the Daejeon (Indong), Yudeung (Boksu) and Gap (Hoeduck) streams for TMDL (Total Maximum Daily Load) of nutrients. The observed water quality and streamflow data of the year of 2002 and 2003 were used for calibration, and those of the year 2004 and 2005 were used for validation. Simulated results were evaluated by Estimation Efficiency Analysis (COE), Regression Analysis $(R^2)$ and Relative Error (R.E.) for the nutrients amounts on the monthly and yearly basis by comparing observed load with estimated load obtained by using SWAT2000 simulations. The COE value fur T-N was ranged from 0.59 to 0.78, $R^2$ values for T-N ranged from 0.65 to 0.84, and R.E values fur T-N load ranged from 4% to 20%. COE value far T-N was ranged from 0.59 to 0.73, $R^2$ values for T-P ranged from 0.67 to 0.82, and R.E values for T-P load ranged from 3% to 25%. Estimated results of SWAT2000 simulation for 3 sites (Indong, Boksu, Hoedeok) were reasonably satisfactory. This study indicated that SWAT2000 model could be applicable to estimate the nutrients load from the Gap stream watershed in Korea.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.851-861
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• 2003

Snow accumulation and snow melt was simulated and included in the computation of the watershed runoff for Soyanggang Dam and Chungju Dam. A modified Tank Model was used for the simulation, which has three serial tanks and a pulse response function. The model parameters were estimated through the global optimization method of Shuffled Complex Evolution-University of Arizona (SCE-UA). A watershed was divided into four zones of elevation. The temperature decrease of the zones was a rate of -0.6$^{\circ}C$/100m. Almost all precipitation from December to February become accumulated as snow, and then the snow melts and runs off from March to April. The average runoff with snow melt was greater than the average runoff without snow melt during the period from March to April. The improved amount from snow melt simulation was about one fifth of the observed one for Soyanggang Dam. The increased amount for Chungju Dam was about one fourth of the observed average runoff during the same period. Although the watershed runoff was simulated including snow melt, it was less than the observed one for both of the dams.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.16-23
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• 2012

BACKGROUND: To improve the Daechung reservoir water quality, a quantitative estimation of the delivery load from upper watershed need to be conducted prior to others. To do so, an intensive monitoring is necessary because of the complexity and uncertainty of the delivery load from uppper watershed. However, intensive monitoring need to invest much time, cost, and effort. So, many researcher have developed an equation to estimate the delivery loads. But, relatively little research has been conducted on the applicability of pre-developed equation using other sites. Therefore, the objective of this study was to evaluate application of the equation for BOD, T-N and T-P delivery load. METHODS AND RESULTS: To verify the applicability of the equation, the following equation was used; Delivery loads(kg/day)=generated pollutant loads${\times}(1-{\alpha}){\times}$(daily outflow/${\beta})^{\gamma}$. The equations could be calculated the daily delivery loads of streams without any data of water quality, only with the data of daily runoff of study sites. The equations were applied to Youngdogcheon, Chogangcheon, Bocheongcheon, Sookcheon to examine its applicability using monitoring data. The results showed that the estimated delivery loads were in a good agreement with the observed data and indicated reasonable applicability of the equations. CONCLUSION(s): Overall, the equations were satisfactory in estimation of delivery loads at upper watershed of the Daechung reservoir. Therefore, the equations could be contributed to better water quality management in the Daechung reservoir.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.3
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• pp.39-51
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• 2024

To effectively implement the integrated water management policy outlined in the National Water Management Act, it is essential to analyze agricultural water supply and demand at both basin and water district levels. Currently, agricultural water is primarily distributed through open canal systems and controlled by floodgates, yet the utilization-to-supply ratio remains at a mere 48%. In the case of agricultural water, when analyzing water balance through existing national basin water resource models (K-WEAP, K-MODISM), distortion of supply and regression occurs due to calculation of regression rate based on the concept of net water consumption. In addition, by simplifying the complex and diverse agricultural water supply system within the basin into a single virtual reservoir, it is difficult to analyze the surplus or shortage of agricultural water for each field within the basin. There are limitations in reflecting the characteristics and actual sites of rural water areas, such as inconsistencies with river and reservoir supply priority sites. This study focuses on the development of a model aimed at improving the deficiencies of current water balance analysis methods. The developed model aims to provide standardized water balance analysis nationwide, with initial application to the Anseo standard watershed. Utilizing data from 32 facilities within the standard watershed, the study conducted water balance analysis through watershed linkage, highlighting differences and improvements compared to existing methods.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.41-47
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• 2009

A solution to the problems of recognizing as one spot or detection failures for complex regions, in which many spots representing proteins are overlapped and saturated, is suggested. The accumulated gradients of each point in complex regions are calculated, and the resulting accumulated gradient image segmented using watershed technique. The suggested solution show better and efficient result than existing method for spot separation, detects more protein spots hidden in the image of 2-dimensional electrophoresis, and expands the scope of prediction.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.359-365
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• 1998

A global optimization method known as the Shuffled Complex Evolution method from the University of Arizona(SCE-UA) was used for calibrating a Tank model. The model was calibrated with error-free synthetic data, and the SCE-UA method was found to effectively search optimal parameters. Historical data from an agricultural watershed was used to calibrate and validate the model parameters. The simulated results were in good agreement with the observed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.47-54
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• 1996

본 연구에서는 지표면유출과 중간유출의 수문학적과정을 함께 모의발생 시키는 합성 유역모델이 제시되었다. 본 모델은 디지털지형모델과 상호 연결되도록 하였으며 지형이 복잡한 지역에서도 유출이 시간과 공간적으로 누가계산되어 이 분야의 조사연구에 필요한 정보를 제공할 수 있다. 본모델을 이용 유역의 불투수층 위에 분포해있는 토양의 중간계층과 토양수분의 계산 및 침투/용탈의 과정을 모의 발생시킬 수 있다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.353-358
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• 1998

GRASS-AGNPS model integrated with GIS was applied to rural watersheds having complex land use characteristics and evaluated for its applicability through calibration using observed data. The analyses of raster encoding accuracy and model behavior to runoff, sediment yields and nutrient loads for different cell-size showed that 150 m cell size indicated reasonable applicability of the model. Simulated runoff was in a good agreement with the observed data and simulated peak runoff rate was larger than the observed data. The sediment yield simulated by modified AGNPS model using irregular cell for forest area were less than that of the regular cell method. In predicting sediment yields, the result showed a different trend at each representative rural watershed. Nutrient loads simulated by the model were significantly different from the observed data.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.149-179
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• 2004

In order to understand the taxonomic and ecologic characteristics on ciliates plankton, surface water samples were collected once a weekly from March 2001 to December 2001 except once a monthly from December 2001 to January 2001 and twice a monttdy at February 2001 at Pal'tang reservoir in Korea. Totally 12 species belonging to 10 genera in 7 families of 6 order, were identified and all species new record in Korea. All of them had been recorded in eutrophic water bodies. Succession of dominant species occurred obviously according to seasonality. Large -sized Codonella cratera, Rimostrombidium lacustris, Strobilidium caudatum, Limnostrombidium viride, Pelagostrombidium fallax, Stylonychia sp., Pseudostrombidium plaktonticum and Phascolodon vorticella dominated during the period of outbreak of nanophytoplankton in winter to spring. However, small-sized Rimostrombidium hyalinum, rimostrombidium brachykinetum, Halteria gradinella and Vorticella convallaria occurred when the bacteria abundance increased in summer to autumn.