• Title/Summary/Keyword: SWAT model

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Application of SWAT Model for Simulating Runoff and Water Quality Considering Climate Change (기후변화에 따른 미래 유출 및 수질 모의를 위한 SWAT 모형의 적용)

  • Chung, Eun-Sung;Kim, Sang Ug;Kim, Hyeong Bae
    • Journal of Industrial Technology
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    • v.36
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    • pp.9-16
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    • 2016
  • In the face of increasing impact of climate change due to human activities, there has been an urgent need to resolve the problem in water resources planning management and environmental engineering. Therefore SWAT model was used to identify the impacts and change in hydrological cycle and environmental aspect. The most important step for the development of SWAT model is calibration procedure. Therefore, SWAT-CUP automatic calibration module was used to find some optimal parameters in SWAT model. After calibration in the cheongmicheon basin, SWAT model is used for the projected precipitation and temperature of RCP 4.5 and 8.5 climate change scenarios in AR5. The quantity and quality using SWAT model from 2014 to 2100 were identified. Finally, this study can provide the reasonable finding on impact by climate change.

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Estimation of Runoff Curve Number for Ungaged Watershed using SWAT Model (SWAT을 이용한 미계측 유역의 유출곡선지수 산정)

  • Lee, Jin-Won;Kim, Nam-Won;Lee, Jeong-Woo;Seo, Byung-Ha
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.6
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    • pp.11-16
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    • 2009
  • This study is to suggest the SWAT model as inputs for the estimation of CN (Curve number) if we do not have hourly rainfall and runoff data in the ungaged watershed. The daily CNs were estimated by using SWAT model for Chungju dam watershed and the CNs by hourly rainfall and runoff data in the same period with daily CN estimation were also estimated. Then the daily and hourly CNs were compared each other. The CNs by SWAT model were larger than the actual CNs. 7.4% larger in AMC-I, 1.2% in AMC-II, and 6.3% in AMC-III respectively. If we consider various uncertainties in the estimation of CN, the error of 6.8% could be acceptable for the application in the field.

Estimation of Streamflow Discharges using Kajiyama Equation and SWAT Model (가지야마공식과 SWAT 모형을 이용한 유출량 산정)

  • Shin, Yong-Chul;Shin, Min-Hwan;Kim, Woong-Ki;Lim, Kyoung-Jae;Choi, Joong-Dae
    • KCID journal
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    • v.14 no.1
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    • pp.41-49
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    • 2007
  • In this study, Kajiyama equation and SWAT model were used to estimate the available water resources from 1967 to 2003 at the small scale watershed, located in Dongnae-Myeon, Chunchen, Gangwon. The annual average streamflow for dry years estimated using the Kajiyama equation and the SWAT model were $2,593,779m^3$ and $2,579,162m^3$. The annual average streamflow for wet years were $7,223,804m^3$ and $7,035,253m^3$, respectively. The annual arrange streamflow for the entire 36 year period were $14,868,601m^3$ and $14,214,292m^3$, respectively. The coefficient of determination ($R^2$) and the Nash-Sutcliffe coefficient for comparison between Kajiyama and SWAT were 0.90 and 0.79, respectively. The comparison indicates that the Kajiyama equation and the SWAT model can be used to estimate the streamflow at th study watershed with reasonable accuracy, although the estimated values were not compared with measured streamflow data, which is not available at the small scale study watershed. However, the Kajiyama equation is recommended for estimating available water resources at Dongnae-Myeon watershed because of its ease-of-use and reasonable accuracy compared with the SWAT model, requiring numerous model input and expensive GIS software in operating the model

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The Simulation of Nutrients using SWAT Model and its Application to Estimate Delivery Ratio (SWAT 모형을 이용한 영양물질 모의 및 유달율 추정에의 적용)

  • Choi, Daegyu;Shin, Hyun Suk;Yoon, Young Sam;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.25 no.3
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    • pp.375-385
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    • 2009
  • The estimation of delivery ratio is a essential part of Korean Total Maximum Daily Loads (TMDL) procedure which needs a number of observed stream flow and pollutants data. If observed data were not sufficient, researchers have to find other alternatives. One of them is to make indirect data by using watershed models, such as Soil and Water Assessment Tool (SWAT) and Hydrological Simulation Program - FORTRAN (HSPF) and so on. In this study, indirect daily data was made by using SWAT model. To build the Byongseong-SWAT model accurately, crop cultures are reflected by handling the MGT.file in SWAT model. Especially, mass of manure and schedule of crop culture are inputted through investigating domestic research papers as well as fieldwork. After calibrating SWAT model in comparison with the 22-years flow and pollutants observed outlet data, the delivery ratio of Byongseong watershed is calculated by using daily simulated data during 2004-2007. Empirical equations for delivery ratio through multi-regression analysis are developed by using meteorological and physical factors such as flow, watershed area, stream length, catchment slope, curve number (CN) and subbasin's pollutant discharge loads.

Improvement of Channel Water Quality Module in SWAT (SWAT 모형의 하도 수질 모듈의 개선)

  • Kim, Nam-Won;Shin, Ah-Hyun
    • Journal of Korean Society on Water Environment
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    • v.25 no.6
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    • pp.902-909
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    • 2009
  • With various reservoirs, dams and reduction of water velocity in downstream, rivers in Korea often have characteristics of accumulation of pollutants. Therefore, the main focus of water quality modeling in Korea needs to be shifted from DO to algae and organic matter. Moreover the structures of water quality models should be modified to have capability of simulating BOD which is a key factor of total water pollution load management in Korea as laboratory experiment BOD (Bottle $BOD_5$). In the SWAT model which is one of the widely used water quality models in Korea, the channel water quality module is using main algorithm of the QUAL2E model which has limitations in simulating algae, organic matter and Bottle BOD5 etc. To overcome this hindrance, in this study, the improved channel water quality module of the SWAT model (Q-SWAT) was proposed by linking the algorithms of the QUAL-NIER model which was developed based on the QUAL2E model to the SWAT model. The algorithms estimating the increase of internal organic matter by fractionization algal metabolism process and calculating Bottle $BOD_5$ were added and the results of proposed model were compared to those of the original SWAT model. The results of comparison test are showing that more accurate BOD values can be obtained with the Q-SWAT model and it is anticipated that the Q-SWAT model can be used as an effective tool of decision support through the water quality simulation and long term pollution source analysis.

Simulation on Runoff of Rivers in Jeju Island Using SWAT Model (SWAT 모형을 이용한 제주도 하천의 유출량 모의)

  • Jung, Woo-Yul;Yang, Sung-Kee
    • Journal of Environmental Science International
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    • v.18 no.9
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    • pp.1045-1055
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    • 2009
  • The discharge within the basin in Jeju Island was calculated by using SWAT model, which a Semi-distributed rainfall-runoff model to the important rivers. The basin of Chunmi river of the eastern region of Jeju Island, as the result of correcting as utilizing direct runoff data of 2 surveys, appeared the similar value to the existing basin average runoff rate as 22% of average direct runoff rate for the applied period. The basin of Oaedo river of the northern region showed $R^2$ of 0.93, RMSE of 14.92 and ME of 0.70 as the result of correcting as utilizing runoff data in the occurrence of 7 rainfalls. The basin of Ongpo river of the western region showed $R^2$ of 0.86, RMSE of 0.62 and ME of 0.56 as the result of correcting as utilizing runoff data except for the period of flood in $2002{\sim}2003$. Yeonoae river of the southern region showed $R^2$ of 0.85, RMSE of 0.99 and ME of 0.83 as the result of correcting as utilizing runoff data of 2003. As the result of calculating runoff for the long term about 4 basins of Jeju Island from the above results, SWAT model wholly appears the excellent results about the long-term daily runoff simulation.

Evaluation of SWAT Model for Hydrological Analysis of Hwa-Cheon Watershed (화천 지역의 수문분석을 위한 SWAT 모형의 적용성 평가)

  • Kim, Gi-Cheol;Kim, Jong-Geon;Park, Yun-Sik;Heo, Seong-Gu;Yu, Dong-Seon;Kim, Gi-Seong;Choe, Jung-Dae;Im, Gyeong-Jae
    • KCID journal
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    • v.14 no.2
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    • pp.207-213
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    • 2007
  • For sustainable development at a watershed, environment friendly site-specific management practices need to be developed and implemented. The soil and Water Assessment Tool(SWAT)model has been world-wide used to estimate stream flow, sediment, and nonpoint source pollutant loads, and effects on water quality of different management practices. In this study, the SWAT model was used to estimate the flow resources at Hwacheon areas using Digital Elevation Model(DEM),Land use, precipitation ,wind ,maximum and minimum temperature, solar radiation, humidity of watershed The R2 value and EI value for the comparison of SWAT estimated flow and measured flow were 0.87 and 0.67 respectively for calibration period, and the R2 value and E1 value for validation were 0.75 and 0.67 respectively. The comparison results show what the SWAT model is applicable to simulate hydrology behaviors at this study watershed.

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Evaluation of Evapotranspiration and Soil Moisture of SWAT Simulation for Mixed Forest in the Seolmacheon Catchment (설마천유역 혼효림에서 실측된 증발산과 토양수분을 이용한 SWAT모형의 적용성 평가)

  • Joh, Hyung-Kyung;Lee, Ji-Wan;Shin, Hyung-Jin;Park, Geun-Ae;Kim, Seong-Joon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.12 no.4
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    • pp.289-297
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    • 2010
  • Common practice of Soil Water Assessment Tool (SWAT) model validation is to use a single variable (i.e., streamlfow) to calibrate SWAT model due to the paucity of actual hydrological measurement data in Korea. This approach, however, often causes errors in the simulated results because of numerous sources of uncertainty and complexity of SWAT model. We employed multi-variables (i.e., streamflow, evapotranspiration, and soil moisture), which were measured at mixed forest in Seolmacheon catchment ($8.54\;km^2$), in order to assess the performance and reduce the uncertainties of SWAT model output. Meteorological and surface topographical data of the catchment were obtained as basic input variables and SWAT model was calibrated using daily data of streamflow (Jan. - Dec.), evapotranspiration (Sep. - Dec.), and soil moisture (Jun. - Dec.) collected in 2007. The model performance was assessed by comparing its results with the observation (i.e., streamflow of 2003 to 2008 and evapotranspiration and soil moisture of 2008). When the multi-variable measurements were used to calibrate the SWAT model, the model results showed better agreement with the measurements compared to those using a single variable measurement by showing increases in coefficient of determination ($R^2$) from 0.72 to 0.76 for streamflow, from 0.49 to 0.59 for soil moisture, and from 0.52 to 0.59 for evapotranspiration. The findings highlight the importance of reliable and accurate collective observation data for improving performance of SWAT model and promote its facilitation for estimating more realistic hydrological cycles at catchment scale.

Simulation of the Reduction Effect of Soil Loss Using SWAT Model (SWAT 모형을 이용한 토양유실량 저감효과 모의)

  • Jeong, Jin-Kweon;Kim, Hwan-Gi
    • Journal of Environmental Impact Assessment
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    • v.17 no.4
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    • pp.243-253
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    • 2008
  • The purpose of this study was to simulate the reduction effect of soil loss in the Yongdam reservoir watershed using SWAT model. To evaluate accuracy for flow and sediment yield of SWAT model, calibration was performed for the period from Jan. 2002 to Dec. 2003, and the verification for Jan. 2005 to Dec. 2005. The calibration and the verification were carried out using data observed at the Cheoncheon gaging station. The $R^2$ and EI values in terms of a flow were 0.8 and 0.78 respectively for calibration, whereas they for verification were 0.88 and 0.86 respectively. In terms of a sediment yield, they were 0.7 and 0.48 respectively for calibration, whereas for verification were 0.64 and 0.54 respectively. As a results from model simulation, annual mean soil loss rates in terms of forest, paddy and upland were 0.02 ton/ha/yr, 0.15 ton/ha/yr and 7.58 ton/ha/yr, respectively. The results show that the land use type of a upland has more significant impact on a total soil loss as well as a sediment yield than other types of land use. The sediment delivery ratio was determined to be about 0.35. In this study 2 land cover change scenarios for upland area were considered. These scenarios were used an input to SWAT model in order to evaluate their impact on soil loss and sediment delivery. The results show that a reduction of the upland area would reduce the soil loss and sediment yield.

Analysis of Watershed Runoff and Sediment Characteristics due to Spatio-Temporal Change in Land Uses Using SWAT Model (SWAT 모형을 이용한 시.공간적 토지 이용변화에 따른 유량 및 유사량 특성분석)

  • Shin, Yong-Chul;Lim, Kyoung-Jae;Kim, Ki-Sung;Choi, Joong-Dae
    • KCID journal
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    • v.14 no.1
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    • pp.50-56
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    • 2007
  • In this study, the Soil and Water Assessment Tool (SWAT) model was used to assess spatiotemporal effects on watershed runoff and sediment characteristics due to land uses changes from 1999 to 2002 at the small watershed, located in Chuncheon-si, Gangwon province. The annual average flow rate of Scenario I (long-term simulation using land use of 1990), II (long-term simulation using land use of 1996), III(long-term simulation using land use of 200) and IV(simulation using land use of 1990, 1995, and 2000) in long-term simulation) using the SWAT model were 29,997,043 m3, 29,992,628 m3, 29,811,191 m3 and 29,931,238 m3, respectively. It was shown that there was no significant changes in estimated flow rate because no significant changes in land uses between 1990 and 2000 were observed. The annual average sediment loads of Scenarios I, II, III and IV for 15 year period were 36,643 kg/ha, 45,340 kg/ha , 27,195 kg/ha and 35,545 kg/ha, respectively. The estimated annual sediment loads from Scenarios I, II, and III, were different from that from the scenario IV, considering spatio-temporal changes in land use and meterological changes over the years, by 10%, 127%, and temporal changes in land use and meterological changes over the years, by 10%, 127%, and 77%. This can be explained in land use changes in high soil erosion potential areas, such as upland areas, within the study watershed. The comparison indicates that changes in land uses upland areas, within the study watershed. The comparison indicates that changes in land uses can affect on sediment yields by more than 10%, which could exceed the safety factor of 10% in Total Maximum Daily Loads (TMDLs). It is, therefore, recommended that not only the temporal analysis with the weather input data but also spatial one with different land uses need to be considered in long-term hydrology and sediment simulating using the SWAT model

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