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Characteristics of stormwater runoff from urbanized areas (도시화된 토지이용에서 유출되는 강우유출수의 유출특성분석)

  • Mercado, Jean Margaret R.;Geronimo, Franz Kevin F.;Choi, Jiyeon;Song, Young-Sun;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.14 no.2
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    • pp.159-168
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    • 2012
  • Stormwater runoff affects the quality of surface water and groundwater due to the nonpoint sources (NPSs) of pollutants that it carries during storm events. Typically, urbanized areas experience high pollutant mass emission because of paved roads and other areas which are all highly impervious. For this reason, proper identification of the levels of pollutants from the watershed area is important to pass the Ministry of Environment of the Republic of Korea's water quality standards in rivers and streams. This research was conducted in order to determine and quantify the different constituents present in stormwater runoff generated from highly impervious areas in Cheonan City, Korea. Also, the average event mean concentration (EMC) of stormwater runoff from paved areas was compared with EMCs of other countries to determine the possible causes of its occurrence. In addition, the occurrence of first flush phenomenon was studied in order to find the first flush criteria to be used on the design of best management practices. The results show the pollutant concentration of stormwater runoff was higher than other countries due its landuse and relatively small size of catchment area. During the first 30 minutes of the rainfall events, occurrence of first flush phenomenon was highly evident. Several factors affected the pollutant concentrations in the stormwater such as landuse type, geographic and topographic characteristics,catchment area and amount of rainfall. This research can provide guidance in achieving an effective NPS pollution management applicable to highly urbanized areas in the future.

Operational Variables and Performance of Hydrodynamic Separator Treating Rainfall Runoff from Bridge (수리동력학적 분리장치에 의한 교량에서의 비점원 오염물질 처리시 운전변수와 분리효율에 관한 연구)

  • Kim, Yeonseok;Yu, Jianghua;Kim, Youngchul
    • Journal of Korean Society on Water Environment
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    • v.27 no.3
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    • pp.342-348
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    • 2011
  • A hydrodynamic separator using natural free energy provided by bridge was operated for the treatment of stormwater runoff. The separator was automatically controlled by using electronic valve which is connected with pressure meter. Normally the separator was opened during dry days, but it was closed after the capture of first flush. The results indicated that the average pressure and the flow rate were directly affected by the rainfall intensity. The pressure was more than 3 meters as the rainfall intensity was above 5 mm/hr. The percent volume of underflow decreased as the pressure and flow rate increased, but the percent volume of overflow showed an opposite behavior. The concentration of total suspended solids (TSS) in underflow increased as a function of increasing pressure while it decreased in overflow. The TSS separation efficiency was evaluated based on mass balance. It ranged from 30% to 90% with the pressure ranging from 2 to 10 meters, and it was proportional to pressure and flow rate. The analysis of water balance indicated that around 13% of total runoff was captured by the separator as a first flush, and this runoff was separated as underflow and overflow with the respective percent volume of 29% and 71%. The pollutants budget was also examined based on mass balance. The results showed that the percent of TSS, $COD_{cr}$, TN and TP in underflow were 73%, 59%, 7.6% and 49%, respectively.

Analysis of Storm Water Run-off Characteristics during Wet Weather (강우시 합류식 하수관거의 유출특성 분석)

  • Choi, Sung-Hyun;Choi, Seung-Chol;Park, Eun-Young;Rim, Jay-Myoung
    • Journal of Industrial Technology
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    • v.22 no.B
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    • pp.95-101
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    • 2002
  • Much of domestic city is served by combined sewer system rather than separate sanitary or storm sewers. During wet weather, when the volume of sanitary sewage and storm water entering the combined sewers exceeds the system capacity, the system is designed to overflow at several designated CSOs. The objective of this research is to have grasp of characteristics of combined sewer runoff and to evaluate efficiently the intercepted volume of CSOs. During the wet weather in first rainfall, SS load at each site H-1, H-2, and H-3 were 600kg/event, 370kg/event, and 289kg/event, SS load at each site in second rainfall were 216kg/event, 113kg/event, and 37.2kg/event. EMCs at each site were 702mg/L, 816mg/L, 861mg/L in first rainfall and 99.9mg/L, 161.9mg/L, 103.6mg/L in second rainfall, respectively. First flush coefficients b at each site were 0.237, 0.166, and 0.151.

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Characterization of Stormwater Pollutants Runoff in Industrial Complex (강우시 산업단지에서의 오염물질 유출특성)

  • Bang, Ki-Woong;Lee, Jun-Ho;Choi, Jong-Soo
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.2
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    • pp.341-353
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    • 2000
  • The purpose of this study is to investigate the characteristics of pollutants overflow on storm events and the first flush analysis in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. Water quality parameters of stormwater runoff such as $BOD_5$, COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, n-Hexane extracts, Cr, Cu, Pb and Fe were analyzed. During the storm events, measured concentration ranges of $BOD_5$, COD, SS, $NO_3-N$, TKN, $PO_4-P$, TP, r-Hexane extracts, Cr, Cu, Pb and Fe were 2~324 mg/L, 5~810 mg/L, 1~1,110 mg/L, 0.01~10.89 mg/L, 0.1~59.8 mg/L, 0.08~7.02 mg/L, 0.1~7.8 mg/L, 0.1~1,723.6 mg/L, 0.001~0.363 mg/L, 0.001~0.488 mg/L, 0.001~1.28 mg/L, and 0.26~18.91 mg/L, respectively in the industrial complex watersheds. And a quantitative of first flush has been presented. First flush occurs more frequently as the ratio of impervious area increases.

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Runoff Characteristics of Non-point Source Pollutants from Different Forest Types During Rainfall Events (활엽수림, 침엽수림 및 혼효림 지역의 강우시 비점오염물질 유출특성)

  • Shin, Minhwan;Shin, Dongsuk;Lee, Jaewoon;Choi, Jaewan;Won, Chulhee;Seo, Jiyeon;Choi, Yonghun;Choi, Joongdae
    • Journal of Korean Society on Water Environment
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    • v.26 no.3
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    • pp.507-517
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    • 2010
  • Long-term monitoring was conducted to identify the runoff characteristics of non-point source according to the three forest types (deciduous forest, coniferous forest and mixed forest) in this study. Rainfall events of each deciduous forest, coniferous forest, and mixed forest were 10, 8, 12, respectively. Average runoff depth and coefficients of each forest type were founded to be coniferous forest and were followed by others in turns : deciduous forest, and mixed forest because various conditions (i.e., rainfall property, Antecedent Precipitation Index (API), soil property, slope, and forest management) could change runoff characteristics. In the analysis of the first flush phenomenon, it showed that SS and T-P were sensitive for the first flush phenomenon. The first flush phenomenon of them were showed differently by rainfall intensity, rainfall duration, and amount of rainfall. The research results indicated that range of the Event Mean Concentration (EMC) values in deciduous forest were 0.8~2.4 mg/L for $BOD_5$, 2.0~13.4 mg/L for $COD_{Mn}$, 1.3~2.9 mg/L for DOC, 1.150~3.913 mg/L for T-N, 0.010~0.350 mg/L for T-P and 3.1~291.8 mg/L for SS and in coniferous forest were 0.8~2.2 mg/L for $BOD_5$, 1.9~3.6 mg/L for $COD_{Mn}$, 1.0~2.0 mg/L for DOC, 1.025~2.957 mg/L for T-N, 0.002~0.084 mg/L for T-P and 0.8~5.4 mg/L for SS. Also, range of the EMC values in mixed forest were 1.3~2.3 mg/L for $BOD_5$, 2.4~4.8 mg/L for $COD_{Mn}$, 1.1~2.1 mg/L for DOC, 0.385~2.703 mg/L for T-N, 0.016~0.080 mg/L for T-P and 2.3~30.0 mg/L for SS.

An Analysis of First Flush Phenomenon of Non-point Source Pollution during Rainfall-Runoff Events from Impervious Area (불투수성 지역의 강우유출수에 대한 비점오염물질의 초기유출현상 분석)

  • Ahn, Tae-Ung;Bum, Bong-Su;Kim, Tae-Hoon;Choi, I-Song;Oh, Jong-Min
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.9
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    • pp.643-653
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    • 2013
  • In this study, trend analysis was performed by various runoff analysis method of Non-point Pollution Source(NPS) at the impervious area. The characteristics of rainfall at impervious area appeared to be influenced by rainfall strength and it appeared that first flush phenomenon occurs often if rainfall strength acts largely. It is judged that the measure is required to be prepared against that now that concentration difference of non-point pollution source appeared to be big by precedent number of days of no rainfall. As the result of calculating Decrease Rate (DR) by first flush of non-point pollution source, it is judged that it is important to prepare the measure against the pollutants about initial rain and it is necessary to calculate the capacity of non-point pollution source processing facilities regarding that now that the non-point pollution source integrated at impervious area showed the characteristics that are flowed out in high concentration by initial rain in case of non-rainfall considering the characteristics of non-point pollution source at impervious area. When taking 50% of non-point pollution source as the standard for decrease rate that was evaluated previously, it appeared as 15~60 min in case of TSS and it appeared as 30~90 min in case of organic compound, but the characteristic whose decrease rate is below 50% also appeared even till rainfall-runoff ends. Based on that, it is judged that it could be used as the reference when designing the structural BMPs facilities later.

Development of a Sustainable First Flush Management System for Urban Stream Water Quality Management (도시 하천 수질 관리를 위한 지속가능 초기 강우 오염 관리 시스템의 개발)

  • Seo, Dongil;Lee, Tongeun;Kim, Jaeyoung;Koo, Youngmin
    • Ecology and Resilient Infrastructure
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    • v.3 no.4
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    • pp.247-255
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    • 2016
  • Non-point pollutants from surface runoff during rainfall exert adverse effects on urban river water quality management. In particular, the first flush effect during the initial phase of rainfall can deliver significant amounts of pollutant loads to surface waters with extremely high concentrations. In this study, a sustainable first flush effect management system was developed by using settling and filtration that require no additional power or chemicals. A pilot scale experiment has shown that the removal of total suspended solid (TSS), total nitrogen (TN) and total phosphorus (TP) are in ranges of 84 - 95%, 31 - 46%, and 42 - 86%, respectively. An Integrated Stormwater Runoff Management System (ISTORMS) was also developed to efficiently manage the developed system by linking weather forecast, flow rate and water quality modeling of surface runoff and automatic monitoring systems in fields and in the system. This study can provide effective solutions for the management of urban river in terms of both quantity and quality.

Runoff Characteristics of Nonpoint Pollutants Source in Urban Area (중소도시지역 비점오염물질의 유출 특성)

  • Lee, Geon-Jik;Seong, Jin-Uk;Park, Ju-Hyun;Joe, Gyu-Soo;Park, Je-Chul
    • Journal of Environmental Science International
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    • v.19 no.7
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    • pp.819-827
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    • 2010
  • This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.

Analysis of Pollutant Loads of Rainfall Runoff From Agricultural-Forestry (강우시 농지-임야지역으로부터 발생하는 오염부하량 분석)

  • Yur, Joong Hyun;Kim, Geon Ha;Seo, Jung Moo
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.888-892
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    • 2004
  • 농지, 임야지역에서의 강우유출수 수질의 파악은 수자원 수질관리에 있어서 바탕수질(Background water quality)이기 때문에 물관리에 있어 매우 중요한다. 본 연구는 농지와 임야가 혼합된 도시외곽지역에서 강우시에 발생하는 강우유출수의 수질 및 오염부하량에 대하여 유역특성이 다른 두 지역에서 분석을 실시하였다. 연구 대상 유역은 임야와 농경지가 주를 이루는 지역으로 농지의 비율이 자자 $0.4\%$$35.9\%$인 유역이다. 측정은 건기에서부터 강우기 때까지 각 유역 당 10개의 강우 사상에 대하여 실시하였다. 측정 대상 항목으로는 pH, SS, TCOD, SCOD, BOD, TP, TN, $NH_3-N$, $NO_3-N$, $PO_4-P$, Total coliform, Escherchia Coli를 측정하였고, pollutograph, loadgraph을 작성하였다. 분석 결과 농지의 비율이 큰 유역에서 발생하는 오염부하량이 모든 수질 항목에서 높게 나타났으며, SS, 유기물, 미생물 항목에서 초기강우세척철상(first flush)을 보이고 있었다. 또한 측정 자료에 내한 동계분석결과 SS항목과 유기물 항목은 높은 상관관계를 나타내고 있었으며, 강우에 따른 오염부하량은 누승함수, 2차함수의 형태로 증가하였다.

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Effect of Stormwater Runoff on Combined Sewer Overflows in Korea

  • Kim, Lee-Hyung;Kim, Il-Kyu;Lee, Young-Sin;Lim, Kyeong-Ho
    • Journal of Korean Society of Hazard Mitigation
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    • v.7 no.4
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    • pp.107-113
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    • 2007
  • The Kuem-River, one of the largest rivers in Korea, is the primary water source for more than 4 million people in Kongju city and surrounding area. To study the effect of stormwater runoff to CSOs, twelve monitoring sites were selected in two large cities (City of Kongju and City of Buyeo) near the Kuem-River. Monitoring was reformed by collecting grab samples, measuring flow rates during dry and wet seasons during over two rainy seasons. Generally the flow rate of wastewater in combined sewers was rapidly decreased after 23:00 P.M. and gradually increased from 06:30 A.M. in all sites during the dry season. The concentrations of pollutant increase approximately 5 to 7 fold for TSS and 1.5 to 2.5 fold for BOD during the rainy season. Monitoring and statistical analysis show that the groundwater contributes on sewage volume increase (average 25-45% more) during dry periods and the stormwater runoff contributes approximately 51-72% increase during rainy periods. Generally the concentrations of combined sewage were more polluted during the first flush period than after the first flush during a storm event.