• Title, Summary, Keyword: Mass first flush (MFFn)

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The Applicability for Estimating MFFn by SWMM in The Trunk Road (간선도로에서 MFFn 산정 시 SWMM의 적용성 평가)

  • Kwon, Hun-Gak;Lee, Jae-Woon;Yi, Youn-Jeong;Yoon, Young-Sam;Lee, Chun-Sik;Lee, Jae-Kwan
    • Journal of Korean Society on Water Environment
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    • v.27 no.5
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    • pp.605-616
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    • 2011
  • The first flush phenomenon and the Mass First Flush (MFFn) were analyzed for various rainy events in trunk road. Applicability for estimate MFFn using SWMM was evaluated by comparision with observed MFFn. First flush phenomenon was investigated by normalized cumulated (NCL) curve of every pollutant based on ten times of rainfall events monitoring data from 2008 to 2009. As a result, magnitude of first flush phenomenon varied with the pollutants and rainfall events. First flush phenomenon was detected highly in the trunk road. MFFn was estimated by varying n-value from 10 to 90% on the rainfall events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good ($R^2$=0.956). As the final outcome, we have good reliability, estimation and application of MFFn using model seem statistically possible.

Determination of EMC and MFFn Rainfall Runoff in Songcheon, Doam Lake Watershed (도암호 유역 송천에서의 강우유출수 분석을 통한 EMC와 초기세척비율 (MFFn) 산정)

  • Kwon, Hyeokjoon;Kim, Jonggun;Lim, Kyoungjae;Kim, Dongjin;Hong, Eunmi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.62 no.4
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    • pp.13-22
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    • 2020
  • The Doam Lake watershed has a significant impact on the downstream water system due to nutrients and sediment outflow during rainfall caused by steep slopes, soil losses, and fertilization. These non-point sources are unclear in the discharge area and are affected by land use patterns, soil characteristics, and topographical features of the watershed. Therefore, this study conducted rainfall monitoring from July to October 2019 in Songcheon upstream of the Doam Lake watershed, one of the non-point pollution source management areas. Then, after analyzing rainfall runoff, Event Mean Concentration (EMC) and Mass First Flush ratio (MFFn) were calculated to compare and analyze the characteristics of rainfall and the non-point pollutant discharge. As a result of the analysis, it showed various non-point pollutant emission characteristics for each rainfall event. In addition, the concentration of EMC and the MFFn were affected by the average rainfall intensity and the maximum rainfall intensity, and were not significantly affected by the number of antecedent drying days. In the future, it is expected that effective non-point source reduction measures and management measures according to rainfall intensity through continuous monitoring and analysis will be needed.

Estimation of Runoff Characteristics of Nonpoint Pollutant Source in Railroad Area (철도지역의 비점오염원 유출특성)

  • Lee, Chun Sik;Seo, Gyu Tae;Yoon, Cho Hee;Kwon, Heon Gak;Lee, Jae Woon;Cheon, Se Uk
    • Journal of Environmental Science International
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    • v.23 no.3
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    • pp.511-520
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    • 2014
  • The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.

The Estimating MFFn by SWMM in The Transportation Area (SWMM 모형을 활용한 도로 형태별 초기세척비율 산정)

  • Kwon, Hun-Gak;Lee, Jae-Woon;Yi, Youn-Jeong;Shin, Suk-Ho;Lee, Chun-Sik;Lee, Jae-Kwan
    • Journal of Environmental Science International
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    • v.21 no.3
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    • pp.277-287
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    • 2012
  • The MFFn(Mass First Flush) was analyzed for various rainy events(monitoring data from 2008 to 2009) in Transportation area(Highway, National road, Trunk road). Estimated MFFn using SWMM was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good ($R^2$=0.89). Pollutants runoff loads by volume showed Highway 26.6%, National road 44.8%, Trunk road 35.0% at the MFF20(20% by total runoff). A case of MFF30, pollutants runoff loads by volume showed Highway 40.2%, National road 54.3%, Trunk road 46.8%. According to the results, Initial precipitation basis were Highway MFF30, National road MFF20, Trunk road MFF30 when the Non-Point source control facilities set up.

Comparative Analysis of Non-point Pollution by Rainfall Runoff Characteristics in Songcheon, Doam Lake Watershed (도암호 유역 송천에서의 강우시 비점오염물질 유출 특성 비교분석)

  • Kwon, Hyeok Joon;Jung, Dong Sung;Kim, Jong Gun;Lim, Kyoung Jae;Hong, Eun Mi
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.140-140
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    • 2020
  • 도암호 유역 위치한 강원도 평창군 대관령면 일대는 고랭지 농업이 주로 이루어지는 곳으로 강우시 토양 유실로 인한 하천의 수질오염이 빈번하게 발생하고 있다. 비점오염원은 강우시 호수와 하천으로 유입되는 특징을 가지고 있으며 불특정 발생원에서 불특정 기상조건과 경로에 의해 발생하여 지속적인 모니터링에는 어려움이 따른다. 이러한 비점오염원 중에서도 농촌지역에서 발생되는 비점오염원은 정확한 기작이 분석되지 않고 있어 수질오염에 큰 문제가 되고 있다. 본 연구는 도암호 유역 송천에서 2019년 7월부터 10월까지 6회 모니터링을 실시하였다. 이후 각 강우사상에서 비점오염물질의 유출에 미치는 강우요인(선행무강우일수, 강우지속시간, 총 강우량, 최대강우량, 평균강우량)을 분석하였다. 또한 강우유출수 분석을 통해 유량가중평균농도(EMC, Event Mean Concentration)을 산정하여 각 강우사상에서 유출된 오염원의 농도를 정량화하였으며, 초기세척비율(MFFn, Mass First Flush ratio)를 산정하여 강우초기에 유출된 오염원의 농도를 알아보았다. 분석결과 강우의 특성과 모니터링 시기별 영농단계에 의해 강우사상별 오염원의 농도와 초기세척비율의 차이를 보인 것으로 판단된다. 추후 지속적인 모니터링과 분석을 통한 강우강도에 따른 효율적인 비점오염원 저감대책과 관리 방안이 필요할 것으로 보인다.

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