• 상하수도학회지
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• 제23권1호
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• pp.15-22
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• 2009

This study reports the serial use of a 3-D hydrodynamic model, EFDC-Hydro and a dynamic water quality model WASP7.2 that are maintained by USEPA. The 48 km section of the Geum River downstream between Daechung Dam and Gongju was selected as a sample study site. Topographical information was used to accurately represent morphology of the study site and boundary conditions were derived from governmental databases including WAMIS by Ministry of Land and Ocean and WEIS by Ministry of Environment. EFDC-Hydro was successfully calibrated for observed water level and WASP was calibrated using monthly observed water quality data obtained from the above sources. It was found that the current water quality target of BOD for the Geum River-H point could not be met on monthly basis though every other tributary of the area would meet its own water quality target as assigned in Korean TMDL. This study proposed the new target BOD water quality for the Gabcheon and Mihocheon as 4.3 and 3.6 mg/l, respectively so that the Geum River-H point can meet the target. When Sejong City is constructed, it is estimated that effluent discharge limit of BOD must be less than 4.5 mg/l to meet water quality of the point. This study shows that it is possible to carry out more precise modeling considering both water movement and water kinetics by using EFDC and WASP simultaneously.

• 한국물환경학회지
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• 제33권2호
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• pp.219-229
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• 2017

A watershed-river linked modeling system was developed to forecast the water quality, particularly weekly changes in chlorophyll-a concentration, of the Yeongsan River, Korea. Hydrological Simulation Program-Fortran (HSPF) and Environmental Fluid Dynamics Code (EFDC) were adopted as the basic model framework. In this study, the EFDC model was modified to effectively simulate the operational condition and flow of multi-functional weirs constructed in the main channel of rivers. The model was tested against hydrologic, water quality and algal data collected at the right upstream sites of two weirs in 2014. The mean absolute errors (MAEs) of the model calibration on the annual variations of river stage, TN, TP, and algal concentration are 0.03 ~ 0.10 m, 0.65 ~ 0.67 mg/L, 0.03 ~ 0.04 mg/L, and $9.7{\sim}10.8mg/m^3$, respectively. On the other hand, the MAE values of forecasting results for chlorophyll-a level at the same sites in 2015 range from 18.7 to $22.4mg/m^3$, which are higher than those of model calibration. The increased errors in forecasting are mainly attributed to the higher uncertainties of weather forecasting data compared to the observed data used in model calibration.

• 농업과학연구
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• 제46권1호
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• pp.67-78
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• 2019

The purpose of this study was to predict the water quality using the RNN (recurrent neutral network) and LSTM (long short-term memory). These are advanced forms of machine learning algorithms that are better suited for time series learning compared to artificial neural networks; however, they have not been investigated before for water quality prediction. Three water quality indexes, the BOD (biochemical oxygen demand), COD (chemical oxygen demand), and SS (suspended solids) are predicted by the RNN and LSTM. TensorFlow, an open source library developed by Google, was used to implement the machine learning algorithm. The Okcheon observation point in the Geum River basin in the Republic of Korea was selected as the target point for the prediction of the water quality. Ten years of daily observed meteorological (daily temperature and daily wind speed) and hydrological (water level and flow discharge) data were used as the inputs, and irregularly observed water quality (BOD, COD, and SS) data were used as the learning materials. The irregularly observed water quality data were converted into daily data with the linear interpolation method. The water quality after one day was predicted by the machine learning algorithm, and it was found that a water quality prediction is possible with high accuracy compared to existing physical modeling results in the prediction of the BOD, COD, and SS, which are very non-linear. The sequence length and iteration were changed to compare the performances of the algorithms.

• 대한지질공학회:학술대회논문집
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• 대한지질공학회 2002년도 정기총회 및 학술발표회
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• pp.235-248
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• 2002

지하수개발 기술의 발전과 생활여건 개선으로 지하수의 사용이 증가되면서 지하수에 대한 관리상 어려움과 여러 문제점들이 발생하고 있다. 지하수관리체계의 부실, 관리 인원의 부족, 무분별한 개발 등으로 지하수 오염 및 수량부족 현상이 가중되고 있고, 또한 지하수관 정의 관리가 어려워 지역적인 과잉개발이나 폐공이 방치되는 현상이 나타나고 있다. 본 논문은 GIS를 이용한 지하수관리의 시스템구축 모델을 제시하고, 지하수관리시스템에 필요한 분석기능 및 지하수관리 방법을 구현하여 효율적인 지하수관리가 이루어질 수 있도록 하는데 목적이 있다. 지하수개발의 위치정보를 기록하고 개발자료와 현장조사자료 등의 여러 자료를 D/B화 하였다. 또한 위성영상을 이용한 선구조 분석 자료와 수리시험 자료, 수질조사 자료 등을 활용하여 지역별 특성 값을 주제도로 작성하였고, 이러한 자료들을 활용하여 지하수 모델링 기초자료를 자동 생성할 수 있도록 하였다. 신규 지하수개발 위치에 대하여 주변의 지하수개발현황 및 오염원 현황, 선구조의 발달, 오염취약성도(DRASTIC), 수질조사 등의 자료를 손쉽게 파악할 수 있는 장점이 있다. 지하수관리시스템은 이러한 기능들을 이용하여 지하수개발 적지선정이 가능하다.

• Korean Journal of Hydrosciences
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• 제10권
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• pp.35-46
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• 1999

An integrated system of GIS and water quality model was suggested including the pollutant loads from the watershed. The developed system consits of two parts. First part is the information on landuse and several surface factors concerning the overland flow processes of water and pollutants. Second part is the modeling modules which include storm event pollutant load model(SEPLM), non-storm event pollutant load model(NSPLM), and river water quality simulation model(RWQSM). Models can calculate the pollutant load from the study area. The databases and models are linked through the interface modules resided in the overall system, which incorporate the graphical display modules and the operating scheme for the optimal use of the system. The developed system was applied to the Chungju multi-purpose reservoir to estimate the pollutant load during the four selected rainfall events between 1991 and 1993, based upon monthly basis and seasonal basis in drought flow, low flow, normal flow and wet flow.

• 한국수자원학회논문집
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• 제56권5호
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• pp.337-345
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• 2023

미세플라스틱 분석에는 많은 비용과 인력, 그리고 긴 분석시간이 필요하기 때문에 하천에서의 연속적 미세플라스틱 관측에는 한계가 있다. 이와 같은 한계는 일반적으로 모형의 활용을 통해 보완될 수 있으나, 미세플라스틱의 거동 모의를 위한 모형 연구는 상당히 제한적으로 수행되었다. 따라서, 본 연구에서는 하천 수질 오염원의 거동을 이해하고 예측하는 데 많이 활용되는 물리식 기반 동적 수치모형인 Water Quality Analysis Simulation Program (WASP)의 미세플라스틱 오염예측에의 적용성을 검토하였다. 이를 위해, 안양천 대상 미세플라스틱 실측자료와 WASP8의 생화학적 산소요구량(BOD)과 부유물질(SS) 상태변수를 미세플라스틱 대리인자로 이용하여 안양천의 미세플라스틱 농도를 모의하였다. 모의결과, SS를 이용한 미세플라스틱 모의가 BOD를 이용한 모의보다 미세플라스틱 농도 모의에 더 좋은 성능을 나타냈다. 이는 상태변수로 이용한 각 수질인자의 특성에 기인한 것으로 생물화학적 지표인 BOD는 생물화학적으로 매우 안정된 미세플라스틱 모의에 대리인자로 사용하기에 적합하지 않은 것으로 판단된다. 반면, 미세플라스틱과 물리적 거동이 유사한 SS의 경우 미세플라스틱의 농도변화 추세를 잘 반영하였다. 향후, 보다 엄밀한 모형을 통한 미세플라스틱 오염 예측을 위해서는 미세플라스틱 재현성 평가를 위한 다양한 환경조건에서의 기초적인 미세플라스틱 조사 연구가 요구되며, 미세플라스틱 입력자료의 단위문제가 해결되어야 한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.652-656
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• 2007

The major streams in South Korea have established the TMDL(Total Maximum Daily Loads) regulation for just 4 years. Traditional concepts in water quality management in South Korea are based upon the selection of a design streram flow which is 10-year averged flow exeedance probability 75%(Q275). That is, a single flow value based upon average long term flow conditions is chosen for application in dilution calculations, permit design, water quality modeling, etc. While these TMDLs seems to satisfy the requirement of the target water quality regulations, they have contributed little to any watershed/waterbody assessment and restoration plans. These types of TMDLs do little to characterize the problems the TMDLs are intended to address. For TMDLs to be more beneficial in the assessment and implementation process, TMDLs should reflect adequate water quality across flow conditions rather than at a single flow value such as average daily flow. In this paper, we developed LDC (load duration curve) methodology for theevaluation of Korean TMDL evaluation based on watershed scaled, physically based on SWAT(Soil and Water Assessment Tool) model.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.479-482
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• 2003

Landsat-TM images were applied for evaluating the spatial variations of flow and water quality at the Saemankeum areas. For supervised classifications, the results from hydrodynamic modeling and water quality data were compared to the reflectance characteristics of the satellite images. Multiple regression analyses indicated that suspended sediment, transparency, salinity, total nitrogen, and total phosphorus showed a good relationship to the signature. Supervised classifications showed spatial variations of the water environments at the areas under construction. The results showed the satellite imagery may be applied for the project areas with a reasonable degree of accuracy.

• 상하수도학회지
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• 제25권5호
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• pp.667-679
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• 2011

In this study, the influences of pollutant from Dae-po Stream and So-gam Stream located at the downstream of Nak-dong River on the water quality at Mul-geum water intake station were analyzed using RAMS model. Field measurements of velocity by ADCP, and water quality distribution of BOD and TP by water sampling were carried out to present the input and verification data for numerical simulations. The comparison between RAM2 and ADCP measurement, which aimed for the analysis of 2-D velocity distribution around Mul-geum water intake station showed that two results matched well along the spanwise direction. The prediction of pollutant concentration by RAM4 agreed fairly well with the measured data except for the points nearby right banks in the vicinity of tributary pollutant source. Flushing effect by the increase of mainstream discharge in Nak-dong River was analyzed to provide the damage mitigation in preparation for the accidental water pollution. With increasing mainstream discharge, high velocity and increased water quantity induced increasing dilution effect, thereby decreasing the inflow pollutant concentration rapidly.

• 환경영향평가
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• 제21권3호
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• pp.445-460
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• 2012

In order to evaluate and predict the environmental impact of the low-trophic-level ecosystem to environmental changes in the Yellow Sea and the East China Sea, an ecological modelling study was undertaken. Simulation results of average distribution patterns and concentrations of water quality factors during the summer by the model were acceptable. Phytoplankton and remineralization rate of organic matter were very important parameters by a sensitivity analysis. Water quality factors showed high values in the estuary of the Yangtze River and in the West and South Sea of Korea and low values in the central area of the Yellow Sea. There is a plume of high values, especially nutrients, off the mouth of the Yangtze that expands or contracts with changes in the discharge strength. Characteristics of responses of water quality factors vary for different scenarios of environmental change, such as land-based pollution sources and atmospheric forcing. It is suggested that changes of light intensity, discharges of input sources, and wind play an important role in the marine ecosystem.