• 상하수도학회지
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• 제25권3호
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• pp.407-417
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• 2011

Nowadays, the high land use, mainly used for urbanization, is affecting runoff loads of non-point pollutants to increase. According to this fact, increasing runoff loads seems like to appear that it contributes to high ratio of pollution loads in the whole the pollution loads and that this non-point source is the main cause of water becoming worse quality. Especially, concentrated pollutants on the impermeable roads run off to the public water bodies. Also the coefficient of runoff from roads is high with a fast velocity of runoff, which ends up with consequence that a lot of pollutants runoff happens when it is raining. Therefore it is very important project to evaluate the quantity of pollutant loads. In this study, I computed the pollutant loadings depending on time and rainfall to analyze characteristics of runoff while first flush storm water and evaluated the runoff time while first flush storm water and rainfall based on the change in curves on the graph. I also computed contribution ratio to identify its impact on water quality of stream. I realized that the management and treatment of first flush storm water effluents is very important for the management of road's non-point source pollutants because runoff loads of non-point source pollution are over the 80% of whole loads of stream. Also according to the evaluation of runoff loads of first flush storm water for SS, run off time was shown under the 30 minute and rainfall was shown under the 5mm which is less than 20% of whole rainfall. These are under 5mm which is regarded amount of first flush storm water by the Ministry of Environment and it is judged to be because run off by rainfall is very fast on impermeable roads. Also, run off time and rainfall of BOD is higher than SS. Therefore I realized that the management of non-point source should be managed and done differently depending on each material. Finally, the contribution ratio of pollutants loads by rainfall-runoff was shown SS 12.7%, BOD 12.7%, COD 15.9%, T-N 4.9%, T-P 8.9%, however, the pollutants loads flowing into the steam was shown 4.4%. This represents that the concentration of non-point pollutants is relatively higher and we should find the methodical management and should be concerned about non-point source for improvement on water quality of streams.

• 한국환경과학회지
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• 제20권8호
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• pp.977-986
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• 2011

This study analyzed the characteristics of stormwater runoff in the orchard areas and quantitatively estimated effluence of nonpoint source pollutants for the volume of runoff. Two target areas under vine cultivation were each $2,000m^2$ and $1,800m^2$, located in Gyeongju City. Since grape was the only crop on the target area, the characteristics of stormwater runoff at vineyard could be evaluated independently. A total of 51 rainfall events in the vineyard area during two years(2008-2009) was surveyed, and 19 of them became stormwater runoff, with rainfall ranging 16.5 - 79.7 mm and antecedent dry period of 1-13 days. The pollutant runoff loads by volume of stormwater runoff showed BOD ranging 19.5 - 45.3% in 30% of runoff volume. The average pollution discharge rate was 32.4%, indicating small first flush effect of BOD. The range of SS concentrations was 5 - 52.0% in 10% of runoff volume, showing the average 28.7% of discharge rate, about 3 times more than rainfall effluent. TOC and TN appeared to be similar to the results of BOD, the average discharge rate of 30.9% and 30.6% for TOC and TN, respectively, for 30% of stormwater runoff volume. Average discharge rate of COD and TP in the same runoff volume was 35.1% and 36%, respectively, showing comparatively high discharge ratio. As the targeted vineyard area was permeable land, the pollution load ratio against rainfall-runoff volume appeared to be 1:1, implying no strong first flush effect for all the survey items.

• 한국농공학회논문집
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• 제54권6호
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• pp.89-99
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• 2012

An upland monitoring was conducted for about 4 years with respect to the water and quality of rainfall-runoff. The objective was to characterize of runoff and nonpoint source (NPS) pollution from a sandy field with 4.5 % in slope under balloonflower (2008-2010) and potato (2011) cultivation. Balloonflower was cultivated without any surface cover but potato was grown under plastic mulching. Runoff rate, EMCs and NPS pollution loads were estimated. The first flush effect was evaluated, and the correlation coefficient among the selected water quality indices were analyzed. Average rainfall size was higher by 2.3 mm when balloonflower was cultivated but average runoff rate was higher by 0.02 when potato was cultivated due to the plastic mulching. EMCs monitored from balloonflower field were higher than potato field except SS and TN, but all NPS pollution loads of potato field were 2.1~22.9 times greater than balloonflower field because of larger runoff volume. As a result of first flush effects, balloonflower and potato field were more influenced by increasing of accumulated rainfall and rainfall intensity rather than first flush. In the result of correlation analysis, there were no evident correlations between runoff and water quality indices. However, there were obvious correlations between SS and the other indices except TN. As a result of this study, it was thought that perennial balloonflower crop could help reduce runoff and NPS pollution loads but annual crop with plastic mulching increase them.

• 한국환경보건학회지
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• 제31권1호
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• pp.1-6
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• 2005

This study was conducted to identify the runoff characteristics of non-point source according to rainfall in Nam watershed. Land-uses of the Nam watershed were surveyed paddy field 4.5%, crop field 6.8%, mountainous 78.7%, urban 2.4%, and etc. 7.7%. Mean runoff coefficients in each area were observed Ⅰ area 0.08, Ⅱ area 0.08, and Ⅲ area 0.05. In the relationship between the rainfall and peak-flow, correlation coefficients(r) were investigated Ⅰ area -0.8609, Ⅱ area 0.6035, and Ⅲ area -0.4913. In the relationship between the antecedent dry period and first flow runoff, correlation coefficients(r) were investigated Ⅰ area -0.9093, Ⅱ area -0.1039, and Ⅲ area -0.7317. The discharge of pollutant concentrations relates to the flow rate of storm-water. In the relationship between the rainfall and watershed loading, exponent values of BOD, COD, SS, and T-N were estimated to 1.2751, 1.2003, 1.3744, and 1.1262, respectively.

• 한국수자원학회논문집
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• 제31권1호
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• pp.3-12
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• 1998

호우의 강우강도는 홍수 수문곡선의 첨두유량이나 도달시간에 영향을 미치는 주요 인자이므로 그 영향을 강우-유출 모형의 매개변수나 모형의 지배방정식에 반영하는 것이 합리적이다. 본 논문에서는강우강도의 변호를 탱크모형 최상단 탱크의 유출공 승수 변화에 반영하는 방안을 연구하였다. 탱크의 구조는 표준4단 탱크에서 최상단 유출공의 승수를 같도록 하고 1,2단 탱크의 유출에 지체시간을 부여한 수정형태이다. 내린천 유역의 여러 홍수에 대하여 최상단 탱크의 유출공 승수와 강우강도의 관계를 분석한 결과 강우강도가 증가할 때 승수 a1도 증가하는 경향이 있으나 그 정도는 다소 약하였다.이 경향을 a1=kI$(I:강우강도,k,m:계수)의 근사식으로 작성하여 모형 검증에 사용하였다. 이때 평균강우강도 I(t)는 시각 t에서 몇 시간 전까지의 이동평균을 사용하고, 계산된 a1이 그 전 값보다 크면 a1의 a1을 갱신하여 처음부터 시각 t까지의 강우량으로 다시 유출을 모의하였다. 검증 결과 강우강도를 반영한 유출공 승수 a1의 적용이 고정된 값의 사용에 비하여 홍수모의 오차를 크게 축소할 수 있었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.208-208
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• 2022

Recently, the frequency of abnormal weather due to complex factors such as global warming is increasing frequently. From the past rainfall patterns, it is evident that climate change is causing irregular rainfall patterns. This phenomenon causes difficulty in predicting rainfall and makes it difficult to prevent and cope with natural disasters, casuing human and property damages. Therefore, accurate rainfall estimation and rainfall occurrence time prediction could be one of the ways to prevent and mitigate damage caused by flood and drought disasters. However, rainfall prediction has a lot of uncertainty, so it is necessary to understand and reduce this uncertainty. In addition, when accurate rainfall prediction is applied to the rainfall-runoff model, the accuracy of the runoff prediction can be improved. In this regard, this study aims to increase the reliability of rainfall prediction by analyzing the uncertainty of the Korean rainfall ensemble prediction data and the outflow analysis model using the Limited Area ENsemble (LENS) and the Grid based Rainfall-runoff Model (GRM) models. First, the possibility of improving rainfall prediction ability is reviewed using the QM (Quantile Mapping) technique among the bias correction techniques. Then, the GRM parameter calibration was performed twice, and the likelihood-parameter applicability evaluation and uncertainty analysis were performed using R², NSE, PBIAS, and Log-normal. The rainfall prediction data were applied to the rainfall-runoff model and evaluated before and after calibration. It is expected that more reliable flood prediction will be possible by reducing uncertainty in rainfall ensemble data when applying to the runoff model in selecting behavioral models for user uncertainty analysis. Also, it can be used as a basis of flood prediction research by integrating other parameters such as geological characteristics and rainfall events.

• 한국물환경학회지
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• 제20권5호
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• pp.494-499
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• 2004

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road ($30cm{\times}30cm$) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 mm/hr to 12 mm/hr of rainfall intensity and decrease over 12 mm/hr of rainfall intensity.

• KIEAE Journal
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• 제14권3호
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• pp.55-63
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• 2014

This study selected and analyzed filter media that can be applied in non-point pollution reduction devices aimed at processing the source of pollution on site for road runoff that increases rapidly in rainfall-runoff in order to improve the water quality of urban areas. First, the factors that affect the quality of runoff caused by sources of non-point pollution include physical and social factors such as the usage of land around the area of water collection, type of pavement and movement of cars and people, as well as rainfall characteristics such as frequency, intensity, amount and duration of rainfall. Second, the purification tests of the filter media were processed for pH, BOD, COD and T-P, and the filter media showed to have initial purification effect at that items. However, the filter media showed to be very effective for the processing of SS, T-N, Zn and Cd from the beginning to the end. Third, for filter media, zeolite and vermiculite showed to be effective for processing SS, T-N, Zn and CD constantly, and composite filter media including zeolite showed to have strong processing effects. The authors conclude that this study can be applied to technical areas and policies aimed at reducing non-point pollution in urban areas and can also contribute to allowing eco-friendly management of rainfall as well as improvement of water quality.

• 한국환경과학회지
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• 제22권4호
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• pp.493-505
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• 2013

This study was to investigate the runoff characteristics of non-point pollutants source at the urban area in Suwon city. The highest T-N and T-P concentration of rainfall runoff observed in agricultural area. In residential area, the highest $BOD_5$ and SS concentration of rainfall runoff was investigated. During rainfall events, the peak concentrations of SS and $BOD_5$ were observed after 1~2 hours of rainfall in urban area. Whereas, the peak concentrations occurred within 1~2 hours after rainfall and then the highest concentrations of SS and $BOD_5$ sharply decreased, showing strong first flush effect in urban area. The EMC results indicated that the highest value of T-N and T-P in agricultural area was observed. While residential area was shown the lowest EMC value as T-N and T-P. Non-point pollutant loads on the land use types in urban area were investigated in the order of residential>industrial>agricultural>highway. $BOD_5$ and SS loads on urban watershed were investigated in the order of Suwon>Hwangguji>Seoho>Wonchunri. Whereas, T-N and T-P loads on urban watershed were investigated in the order of Hwangguji>Suwon>Wonchunri>Seho.

• 청정기술
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• 제19권3호
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• pp.295-299
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• 2013

미국 환경 보호청(Environmental Protection Agency, EPA)의 생물저류 설계기준에 근거한 비점오염원 처리시설의 제거효율 및 성능을 분석하고자 기본 모형 실험장치(basic column reactor, BCR)와 파일럿 규모의 식생 실험 장치를 대상으로 각각 수행하였다. BCR을 이용하여 초기강우 유출수의 유입속도(유량), 식재 층의 조성 및 구성 비율, 등 처리시설의 설계에 필요한 적정인자 값을 도출하였으며 이를 식생 실험 장치에 적용하여 비점오염원의 제거 효율을 분석하였다. 비점오염원으로는 합성된 강우(synthetic rainfall)와 실제 현장(도로변과 주차장)에서 채수한 초기강우 유출수(first rainfall runoff)를 각각 사용하였다. 부유물질(Suspended Solid, SS), 생물학적 산소 요구량(Biochemical oxygen demand, BOD), 화학적 산소요구량(Chemical Oxygen Demand, COD), 총질소(Total Nitrogen, T-N), 총인(Total Phosphorus, T-P) 분석항목 모두 80% 이상을 상회하는 제거효율을 보이고 있음을 확인하였다.