• Title/Summary/Keyword: Filter Strip

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Application and Effectiveness Analysis of SWAT Filter Strip in Golji Watershed (골지천 유역의 최적관리기법 적용에 따른 수질개선효과 분석)

  • Park, Youn Shik;Kwon, Jae Hyouk
    • Korean Journal of Environmental Agriculture
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    • v.33 no.1
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    • pp.30-36
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    • 2014
  • BACKGROUND: Best management practices are often implemented to control nonpoint source pollutants. Best management practices need to be simulated and analyzed for effective Best management practices implementations. Filter strip is one of effective Best management practices in agricultural areas. METHODS AND RESULTS: Soil and Water Assessment Tool model was selected to explore the effectiveness of filter strip to control total phosphorous in Golji watershed. Soil and Water Assessment Tool model was calibrated for flow and total phosphorous by Sequential Uncertainty Fittin ver.2 algorithm provided in Soil and Water Assessment Tool-Calibration and Uncertainty Procedures. Three scenarios defined by filter strip width were applied. The filter strip width of 5 m was able to reduce the most amount of total phosphorous. In other words, the total phosphorous reduction by filter strip of 5 m was 28.0%, while the reduction was 17.5% by filter strip of 1 m. However, the reduction per unit filter strip width were 17.4%, 8.0%, and 4.5% for 1 m, 3 m, and 5 m of filter strips, respectively. CONCLUSION: Best management practices need to be simulated and analyzed so that the BMP scenario can be cost-effective. A large size of BMP might be able to control large amount of pollutants, however it would not be indicated as a cost-effective strategy.

Experiment for Reduction Effectiveness of Pollutants with the Improvement of Infiltration Ability in Vegetation Filter Strip (식생여과대내 침투능력 향상에 따른 오염물질 저감효과에 대한 실험)

  • Lee, Young-A;Choi, I-Song;Oh, Jong-Min
    • Journal of Korea Water Resources Association
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    • v.40 no.2
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    • pp.183-190
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    • 2007
  • Soil layer in vegetation filter strip is one of the very important factor for reduction of non-point pollutants by physical, chemical and biological reactions of it through infiltration process. This study was carried out to prepare more effective vegetation filter strip through modification of soil layer for river water quality improvement. Therefore, the main aims of this study are to compare and evaluate normal (straighten type) and modified (step type) vegetation filter strip, which make artificially change the soil layer to improve infiltration ability, through bench scale experiments. In the results of this study, vegetation filter strip of step type is much more highly reduction effectiveness of pollutants in surface flow compared with normal vegetation filter strip. In case of below effluent, however, it appeared that the vegetation filter strip modified soil layer showed lower reduction effectiveness of pollutants than the general vegetation filter strip. This result was judged because effluent through the vegetation filter strip of step type passed bigger size of aggregate or sand than the vegetation filter strip of straighten type. If we compare it as a definition of pollutant load to estimate total amount of reduced pollutants by vegetation filter strip, reduced pollutants load by step type showed higher than those by straighten type because below effluent amount relied on total effluent amount was higher at step type (4%) than at straighten type (2%). In conclusion, the vegetation filter strip of step type to improve infiltration effect is much more reduction effectiveness of pollutants than vegetation filter strip of straighten type.

Improvement of Sediment Trapping Efficiency Module in SWAT using VFSMOD-W Model (VFSMOD-W 모형을 이용한 SWAT 모형의 초생대 유사 저감 효율 모듈 개선)

  • Park, Younshik;Kim, Jonggun;Kim, Namwon;Park, Joonho;Jang, Won-Seok;Choi, Joongdae;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.24 no.4
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    • pp.473-479
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    • 2008
  • Environment problem has been arising in many countries. Especially, soil erosion has been deemed as one of the biggest issues because sediment causes muddy water and pollutants, such as agricultural chemicals, flow in the stream with this sediment. Many studies, regarding soil loss and non-point source pollution from watershed, has been performed while serious problem has been known. Soil loss occurred in most agricultural area by rainfall and runoff. It makes hydraulic structure unstable, causes environmental economical problems because muddy water destroys ecosystem and causes intake water deterioration. As revealing serious effects of muddy water by sediment, many researches have been doing with various methods. Hydraulic structures establishments such as soil erosion control dams and grit chamber are common. Vegetative filter strip is investigated in this study because vegetative filter strip is designed for reducing sediment from upland areas of the watershed, and it has many functions, not only sediment reduction but also runoff water quality improvement and wildlife habitat. With these positive functions of the vegetative filter strip, the study about vegetative filter strip has been increasing for reducing sediment because it is more effective than hydraulic structures from an environmental perspective. But the sediment trapping efficiency by vegetative filter strip, needs to be investigated and designed first. Therefore the model, VFSMOD-W, was used in this study as it can estimate sediment trapping efficiency of vegetative filter strip under various field, vegetation, weather condition. Sensitive factors to sediment trapping efficiency are studied with VFSMOD-W, and sediment trapping efficiency equation has been derived using two most sensitive factors. It is thought that the equation suggested in this study can be used in Soil and Water Assessment Tool (SWAT), to overcome the limit of SWAT filter strip module, which is based solely on filter strip width.

A Study on Trapping Efficiency of the Non-point Source Pollution in Cheongmi Stream Using VFSMOD-w (VFSMOD-w 모형을 이용한 청미천 유입 비점오염물 저감효율 연구)

  • Son, Minwoo;Byun, Jisun;Yoon, Hyun-Doug;Jung, Tae-Hwa
    • The Journal of the Korea Contents Association
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    • v.16 no.1
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    • pp.140-150
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    • 2016
  • This study aims to investigate the effect of vegetation type, length of vegetative filter strip, and rainfall on trapping efficiency of the non-point source water pollution. Numerical experiments are carried out using VFSMOD-w. It is known from this study that the vegetation having the same value of revised Manning roughness coefficient shows the similar trapping efficiency in VFSMOD-w. When the length of vegetative filter strip increases twice, the trapping efficiency increases negligibly small under the same condition of rainfall. From this finding, it is also known that most of sediment are removed within a certain length of vegetative filter strips. It is concluded that the installation of vegetative filter strip is determined under the consideration of the rainfall characteristics, space of vegetation, and length of vegetative filter strip.

Analysis of Sediment Reduction with VFS and Diversion Channel with Enhancements in SWAT Landuse-Subbasin Overland Flow and VFS Modules

  • Park, Youn-Shik;Kim, Jong-Gun;Kim, Nam-Won;Engel, Bernie;Lim, Kyoung-Jae
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.752-757
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    • 2009
  • In the last decade, many methods such as greet chamber, reservoir, or debris barrier, have been utilized to manage and prevent muddy water problem. The Vegetative Filter Strip (VFS) has been thought to be one of the most effective methods to trap sediment effectively. The VFS are usually installed at the edge of agricultural areas adjacent to stream or drainage ditches, and it has been shown that the VFS effectively removes pollutants transported with upland runoff. But, if the VFS is installed without any scientific analysis of rainfall-runoff characteristics, soil erosion, and sediment analysis, it may not reduce the sediment as much as expected. Although Soil and Water Assessment Tool (SWAT) model has been used worldwide for many hydrologic and Non-Point Source Pollution (NPSP) analysis at a watershed scale. but it has many limitations in simulating the VFS. Because it considers only 'filter strip width' when the model estimates sediment trapping efficiency, and does not consider the routing of sediment with overland flow option which is expected to maximize the sediment trapping efficiency from upper agricultural subbasin to lower spatially-explicit filter strip. Therefore, the SWAT overland flow option between landuse-subbasins with sediment routing capability was enhanced with modifications in SWAT watershed configuration and SWAT engine. The enhanced SWAT can simulate the sediment trapping efficiency of the VFS in the similar way as the desktop VFSMOD-w system does. Also it now can simulate the effects of overland flow from upper subbasin to reflect the increased runoff volume at the receiving subbasin, which is what is occurring at the field if no diversion channel is installed. In this study, the enhanced SWAT model was applied to small watershed located at Jaun-ri in South Korea to simulate diversion channel and spatially-explicit VFS. It was found that approximately sediment can be reduced by 31%, 65%, 68%, with diversion channel, the VFS, and the VFS with diversion channel, respectively.

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Water Quality Prediction at Mandae Watershed using SWAT and Water Quality Improvement with Vegetated Filter Strip (SWAT 모형을 이용한 만대천 유역의 비점오염 예측과 초생대 수질 개선 효과 분석)

  • Lee, Ji-Won;Eom, Jae-Sung;Kim, Bom-Chul;Jang, Won-Seok;Ryu, Ji-Chul;Kang, Hyun-Woo;Kim, Ki-Sung;Lim, Kyoung-Jae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.53 no.1
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    • pp.37-45
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    • 2011
  • Mandae watershed in Gangwon province has been known as one of soil erosion hot spot watersheds within Hanggang basin. Thus numerous efforts have been made to reduce soil erosion and pollutant loads into receiving watershed. However, proper best management practices have not been suggested because no monitoring flow and water quality data were available. Thus, modeling technique could not be utilized to evaluate water quality issue properly at Mandae watershed to develop and implement the best management practices. In this study, the SWAT model was applied to the Mandae watershed, Gangwon province to evaluate the SWAT prediction ability and water quality improvement with vegetated filter strip (VFS) in this study. The Nash-Sutcliffe model efficiency (NSE) and Coefficient of determination ($R^2$) values for flow simulation were 0.715 and 0.802, respectively, and the NSE and $R^2$ values were 0.903 and 0.920 for T-P simulation indicating the SWAT can be used to simulate flow and T-P with acceptable accuracies. The SWAT model, calibrated for flow and T-P, was used to evaluate water quality improvement with the VFS in agricultural fields. It was found that approximately 56.19 % of T-P could be reduced with vegetated filter strip of 5 m at the edge of agricultural fields within the watershed (34.86 % reduction with VFS of 1m, 48.29 % with VFS of 3 m). As shown in this study, the T-P, which plays key roles in eutrophication in the waterbodies, can be reduced with proper installation of the VFS.

Optimization of Vegetative Filter Strip using VFSMOD-w model and Genetic-Algorithm (VFSMOD-w 모형과 유전자 알고리즘을 이용한 식생여과대의 최적화)

  • Park, Youn Shik;Hyun, Geunwoo
    • Journal of Korean Society on Water Environment
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    • v.30 no.2
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    • pp.159-165
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    • 2014
  • Vegetative Filter Strip (VFS) is one of effective Best Management Practices (BMPs) to prevent sediment-laden water problem, is installed at the edge of source area such agricultural area so that sediment occurred in source area is trapped by VFS before it flow into stream or river. Appropriate scale of it needs to be simulated before it is installed, considering various field conditions. In this study, a model using VFSMOD-w model and Genetic Algorithm to determine effective VFS length was developed, it is available to calibrate input parameter related to source area sediment yield through thousands of VFSMOD-w simulations. Useful DBs, moreover, are stored in the model so that very specific input parameters can be used with reasonable values. Compared simulated values to observed data values for calibration, R2 and Nash-Stucliffe model efficiency coefficient were 0.74 and 0.65 in flow comparison, and 0.89 and 0.79 in sediment comparison. The model determined 1.0 m of Filter Length, 0.18 of Filter Slope, and 0.2 cm of Filter Media Spacing to reduce 80% of sediment by VFS. The model has not only Auto-Calibration module also DBs for specific input parameters, thus, the model is expected to be used for effective VFS scale.

Soil Erosion Reduction Plan for Watershed with Sloping Fields of Highland Agriculture by Using GEOWEPP Model (GEOWEPP 모형을 이용한 고랭지 경사지밭 소유역의 토양유실 저감방안)

  • Moon, Jong-Pil;Kim, Tai-Cheol;Lee, Sung-Hyoun;Kwon, Jin-Kyung;Lee, Su-Jang;Lim, Kyoung-Jae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.6
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    • pp.135-144
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    • 2010
  • This study was performed to suggest a soil loss reduction skill through estimating soil erosion from a small watershed including each type of sloping agriland by using GEOWEPP model. Experimental watershed at Gangwon province was selected for very typical sloping fields of highland agriculture in Alpine area. Runoff discharge and sediment load, hourly rainfall amount occurred during storm event were gauged, and weather data were obtained from Daegwallyeong meteorological station. The results of GEOWEPP model estimation showed that relative error values for total runoff discharge and sediment load were 3 %, -14.5 % respectively. Based on the result, soil erosion and waterway path map for each hillslope were made to select target hillslope. Several hillslopes of severe soil erosion were analyezed and then the optimal vegetative filter strip construction width and waterway path to plant grass were decided by using GEOWEPP Model.

Efficiency of Riparian Buffer Zone on Removing Sediment Yield Using SWAT Model (SWAT 모형을 이용한 수변완충지대 설정에 따른 토사유출량 저감 효과분석)

  • Choi, Dae-Gyu;Park, Moo-Jong;Kim, Jae-Chul;Kim, Sang-Dan
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.4
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    • pp.111-118
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    • 2008
  • Riparian buffer zone prevents sediment entry into drainage channels or as a protection from runoff and wind erosion. However, Studies about its removing effect according to Riparian buffer zone are shorted now. In this study, using the SWAT model, Byongseong watershed is built on the Arcview GIS. Using the function of the filter strip in SWAT model, it is also examined about the variation of sediment yield. As a simulation result, the case of constructing riparian buffer zones at subbasins near the outlet shows generally high efficiency on removing sediment yield. In addition, according to the scenario analysis of changing riparian buffer zone width, it is thought that 5-10m riparian buffer zone width is the highest efficiency on removing sediment yields generated from Byeongseong watershed.