• Journal of Korean Society of Rural Planning
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• v.7 no.1 s.13
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• pp.77-88
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• 2001

In order to evaluate the applicability of GWLF model which can efficiently estimate non-point and point source pollutant loadings in rural watershed including urban district, the model was applied to an experimental watershed. The model was calibrated using observed data such as daily runoffs, sediment yields, T-N, and T-P. Simulated daily runoffs and sediment yields by the model using calibrated parameters were in food agreement with the observed data. There were difference between the simulated and observed nutrient loading which was considered resonable. The simulated results by the model showed that T-N, T-P and sediment yields were dependent on the amount of stream runoff discharge and land use. GWLF model is believed to applicable to estimate amount of pollutant loading of non-point source pollution for the water qualify control of agricultural watersheds.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.3
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• pp.23-34
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• 2006

This study reviews the applicability of the GWLF (Generalized Watershed Loading Function) model, which is based on a loading function that requires only a relatively small amount of data, in a small agricultural watershed. The hydrological data was collected from 1996 to 2004 for a study area based on the HP#6 upper stream reservoir small watershed area. This data was then used to calibrate and verify the model. A simulation based on the model yielded $R^2$ values of $0.47\sim0.89$. This is considered to have high applicability when compared to the simulation and the observed results, which yielded relatively high values of $R^2$ for SS (Suspended Solid), TN (Total Nitrogen), and TP (Total Phosphorus) of 0.58, 0.47 and 0.62, respectively. This study provides a useful approach fur researchers selecting appropriate models to use the insufficient measuring data for rural watersheds.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.667-672
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• 2005

The objective of the study is to investigate the application of the mid-range model for agricultural ungaged small watershed. In this study, the need for the selection of an optimal model was presented, and the Feasibility of the GWLF(Generalized Watershed Loading Function) model was examined for agricultural small watershed. The study watershed covers 384ha, and the hydrologic and water quality data were monitored from 1996 to 2004. In the results of the simulation for the calibration period $(1996{\sim}1999)$ and verification $(2002{\sim}2004)$, $R^2$ were $0.70{\sim}0.91$ and RMSE was $2.11{\sim}5.71$. Then, the results of water quality simulation for SS, TN and TP, show that $R^2$ were 0.58, 0.47 and 0.62 respectively. This results were compared with the other research using the detailed models (SWAT, HSPF) for the same watershed and this showed the feasibility of mid-range model for the small watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.269-273
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• 2016

세계적으로 기후변화와 관련한 연구가 증가하고 있다. 국내에서도 기후변화에 따른 수문학적 변화에 대한 연구가 주를 이루어 진행되고 있지만 오염부하량 변화에 대한 연구는 미흡하다. 또한 모형을 이용한 기후변화 예측에 있어 SWAT 모형이 주를 이루어 연구가 진행되고 있다. 본 연구는 기후변화 시나리오인 RCP시나리오 중 RCP 4.5와 RCP 8.5의 자료를 이용하여 용담댐 유역을 대상으로 기후변화에 따른 오염부하량을 예측하기 위하여 GWLF, SWAT 및 SWMM 모형을 선정하여 분석하였다. SWAT, GWLF 및 SWMM에 대하여 적용성 평가를 수행하였다. 기후변화에 따른 미래의 오염부하량을 예측한 결과 모델의 특성 등에 따라 결과가 다르게 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.275-279
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• 2016

기후변화에 따른 강수량변화와 기온변화에 의한 영향이 수질변화에 영향을 미칠 수 있으며, 하천, 호소 등 취수원의 상수도 질적 저하, 나아가 잠재적인 공중보건에까지 영향을 미칠 수 있다. 본 연구에서는 IPCC 에서 발표한 지구기후모형 GCMs의 시나리오 자료를 바탕으로 기상청이 운영하는 기후변화센터의 RCP 시나리오 4.5, 8.5의 데이터 중 금강유역에 기후변화 시나리오 자료를 이용하여 GWLF 모형을 사용하여 금강 유역의 갑천 및 논산천, 대청댐 등 소유역의 2000년부터 2100년까지의 미래 오염 부하량을 모의 하였으며, 연구 결과 RCP 4.5의 경우 오염 부하량이 2100년 까지 전반적으로 증가하는 추세를 보이며, RCP 8.5의 경우 2100년까지 감소하는 추세를 보인다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.209-221
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• 2006

The purpose of this study is to analyze the effects of climate change on the nonpoint source pollution in a small watershed using a mid-range model. The study area is a basin in a rural area that covers 384 ha with a composition of 50% forest and 19% paddy. The hydrologic and water quality data were monitored from 1996 to 2004, and the feasibility of the GWLF (Generalized Watershed Loading function) model was examined in the agricultural small watershed using the data obtained from the study area. As one of the studies on climate change, KEI (Korea Environment Institute) has presented the monthly variation ratio of rainfall in Korea based on the climate change scenario for rainfall and temperature. These values and observed daily rainfall data of forty-one years from 1964 to 2004 in Suwon were used to generate daily weather data using the stochastic weather generator model (WGEN). Stream runoff was calibrated by the data of $1996{\sim}1999$ and was verified in $2002{\sim}2004$. The results were determination coeff, ($R^2$) of $0.70{\sim}0.91$ and root mean square error (RMSE) of $2.11{\sim}5.71$. Water quality simulation for SS, TN and TP showed $R^2$ values of 0.58, 0.47 and 0.62, respectively, The results for the impact of climate change on nonpoint source pollution show that if the factors of watershed are maintained as in the present circumstances, pollutant TN loads and TP would be expected to increase remarkably for the rainy season in the next fifty years.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.5
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• pp.103-113
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• 2000

A decision support system DSS-WQMRA (Decision Support System-Water Quality Management in Rural Area) was developed to help regional planners for the water quality management in a rural basin. The integrated model DSS-WQMRA, written in JAVA, includes four subsystems such as a GIS, a database, water quality simulation models and a decision model. In the system, the GIS deals with landuse and the location of pollutant sources. The database manages each data and supplies input data for various water quality simulation models. the water quality simulation model is composed of the GWLF( Generalized Watershed Loading Function), PCLM(Pollutant Loading Calculation Module) and the WASP5 model. The decision model based on mixed integer programming is designed to determine optimal costs and thus allow the selection of managemental practices to meet the water quality criteria. The methodology was tested with an example application in the Bokha River Basin, Kyunggi Province in Korea. It was proved that the integrated model DSS-WQMRA could be very useful for water quality management including the non-point source pollution in rural areas.

• Journal of Korean Society of Rural Planning
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• v.7 no.1 s.13
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• pp.27-36
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• 2001

Estimation of current and future loading from watershed is necessary for the sound management of water quality of an estuary lake. Pollution sources of point and non-point source pollution were surveyed and Identified for the Koheung watershed. Unit factor method was used to estimate potential pollutant load from the watershed of current conditions. Flow rate and water qualify of base flow and storm-runoff were monitored in the main streams of the watershed. Estimation of runoff pollutant loading from the watershed into the lake in current conditions was conducted by GWLF model after calibration using observed data. Prospective pollutant loading from the reclaimed paddy fields under cultivation conditions was estimated using the modified CREAMS model. As a result, changes of pollutant loading into estuary lake according to non-cultivation and cultivation conditions of reclaimed tidal land were estimated.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.96-105
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• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.