• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.87-92
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• 1999

The evaluation of the effective rainfall is important in the desgin and operation of irrigation systems. But the difinition of the effective rainfall and the method for the estimating effective rainfall is various for each purpose . In this paper, the effective rainfall was defined as amount of rainfall which is remained in the effective soil depth that can be use to consumptive use of crop during growing season. The sol moisture was measured by Neutron prob for the effective rainfall estimation, and theexperiment was conducted for mulched and non-mulched condition of lysimeter during growing season. By the result of analysis and the former definition, the effective rainfall was estimated to be 37.2% for the mulched lysimeter and 40.7% for the non-mulched lysimeter.

• 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.

• 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.

• 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.

• 대한환경공학회지
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• 제35권9호
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• pp.643-653
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• 2013

본 연구에서는 불투수성 지역에서 강우시 비점오염원 유출특성을 파악하고, 다양한 해석방법을 통하여 비점오염물질의 초기유출현상을 규명하고자 하였다. 불투수성 지역에서의 강우사상 특성은 강우강도의 영향을 많이 받는 것으로 나타났으며, 강우강도가 크면 초기유출현상이 뚜렷하게 나타나는 것으로 나타났다. 또한 선행무강우일수에 의해서 비점오염물질의 농도차가 큰 것으로 나타나, 이에 대한 대책 마련이 필요할 것으로 판단된다. 비점오염원의 초기유출에 의한 감소율(DR) 평가 결과, 강우시 불투수성 지역에서의 비점오염 유출특성은 건기시 불투수면에 집적되어 있던 비점오염물질이 초기강우에 의해 높은 농도로 유출되는 경향을 보였기 때문에 초기강우로 인한 비점오염물질에 대한 대책을 마련하는 것은 중요하고, 이와 관련하여 비점오염 처리시설에 대한 용량 산정에 대한 평가도 필요할 것으로 판단된다. 초기유출에 의한 감소율(DR) 경향 분석은 비점오염물질에 대하여 감소율(DR) 50%를 기준으로 조사지점별 강우유출시간을 분석하였는데, TSS는 15~60 min으로 나타났으며, 유기물질은 30~90 min으로 나타나는 경향을 보였지만 강우유출이 끝날 때까지도 감소율(DR)이 50% 이하인 특성도 나타났다. 이를 근거로 하여 향후 구조적 BMPs 시설 설계 시 참고자료로 활용할 수 있을 것으로 판단된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.424-424
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• 2017

Several studies of the world have analyzed the regional rainfall trends in large data sets. However, it reported that the long-term behavior of rainfall was different on spatial and temporal scales. The objective of this study is to determine the local trends of rainfall indices in the Yom River Basin, Thailand. The rainfall indices consist of the annual total precipitation (PRCTPOP), number of heavy rainfall days ($R_{10}$), number of very heavy rainfall days ($R_{20}$), consecutive of dry days (CDD), consecutive of wet days (CWD), daily maximum rainfall ($R_{x1}$), five-days maximum rainfall ($R_{x5}$), and total of annual rainy day ($R_{annual}$). The rainfall data from twelve hydrological stations during the period 1965-2015 were used to analysis rainfall trend. The Mann-Kendall test, which is non-parametric test was adopted to detect trend at 95 percent confident level. The results of these data were found that there is only one station an increasing significantly trend in PRCTPOP index. CWD, which the index is expresses longest annual wet days, was exhibited significant negative trend in three locations. Meanwhile, the significant positive trend of CDD that represents longest annual dry spell was exhibited four locations. Three out of thirteen stations had significant decreasing trend in $R_{annual}$ index. In contrast, there is a station statistically significant increasing trend. The analysis of $R_{x1}$ was showed a station significant decreasing trend at located in the middle of basin, while the $R_{x5}$ of the most locations an insignificant decreasing trend. The heavy rainfall index indicated significant decreasing trend in two rainfall stations, whereas was not notice the increase or decrease trends in very heavy rainfall index. The results of this study suggest that the trend signal in the Yom River Basin in the half twentieth century showed the decreasing tendency in both of intensity and frequency of rainfall.

• 한국습지학회지
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• 제11권1호
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• pp.91-97
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• 2009

본 연구는 강우강도에 따른 계분의 농지 환원시 비점유출로 인하여 수계에 미치는 영향을 연구하였다. 실험실 규모의 반응조를 제작하여 강우강도에 따른 표면유출수와 토양침투수에 대해 조사하였다. 표면유출수의 경우 10mm/hr 이하의 강우에서는 일어나지 않았으며, 20mm/hr에서 일부 유출되는 경향을 보였다. 32.4mm/hr시 가장 높은 표면유출을 보였으며 이때, $BOD_5$는 686mg/L, $COD_{Mn}$은 630mg/L의 농도를 나타내었다. 토양침투수의 경우도 32.4mm/hr의 강우시 많은 양의 계분퇴비가 유출되었고, 43.2mm/hr의 강우시에는 유출되는 양이 큰 폭으로 줄어들었다가 강우량이 증가할수록 유출되는 양이 다시 많아졌다. 비점유출량을 산정한 결과 $BOD_5$는 32.4mm/hr의 강우시 가장 높게 나타났고, T-N은 67.1mm/hr의 강우시 가장 높게 나타났다.

• 한국도로학회논문집
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• 제16권6호
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• pp.9-17
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• 2014

PURPOSES : The purpose of this study is to assess removal efficiency of non-point pollutants and applicability for non-point pollutant reduction facilities by conducting the demonstration project operation. METHODS : In order to analyze removal efficiency of non-point pollutants for facilities such as a grassed swale, a small constructed wetland, a free water surface wetland, a horizontal sub-surface flow wetland, and a sand filtration, the field data including specifications of facilities, rainfall, inflow and runoff rainfall effluent etc. was acquired after occurring rainfall events, and the acquired data was analyzed for removal efficiency rate to assess road non-point pollutants facilities using event mean concentration (EMC) and summation of load (SOL) methods. RESULTS : The results of analyzing rainfall effluent, non-point pollutant sources showed that total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), chrome (Cr), zinc (Zn), and lead (Pb) can be removed through non-point pollutant reduction facilities by 60.3% ~ 100%. Especially removal efficiency of TSS, COD and BOD is relatively higher than removal efficiency of other non-point pollutant sources in all kind of non-point pollutant facilities. CONCLUSIONS : Based on the result of this study, even though natural type of non-point pollutant reduction facilities for roads occupy small areas comparing with drainage basin areas, most of non-point pollutant sources would be removed through the facilities.

• 한국물환경학회지
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• 제23권6호
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• pp.829-836
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• 2007

For the purpose of managing non-point sources, water quality control basins (WQCBs) are often designed to capture rainfall events smaller than extreme events. The design rainfall statistics and runoff capture rates for sizing a WQCB should be derived from the local long-term continuous rainfall record. In this study, the 31-year continuous rainfall data recorded in Busan is analyzed to derive the synthesized runoff capture curve incorporated with SCS curve number.

• 한국환경과학회지
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• 제22권6호
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• pp.733-744
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• 2013

This study was to investigate characteristics of Seoho watershed in Suwon city. $BOD_5$ and SS were selected due to the one of the important factors of the water qualities. Monitoring was conducted monthly for four years during the non-rainfall time. Also, we have been monitored $BOD_5$, $COD_{Mn}$, SS, TN and TP with two times sampling after the rainfalls. The highest concentrations of $BOD_5$ and SS were observed in downstream compare with upstream and midstream during the non-rainfall time. No change was observed in $BOD_5$ and $COD_{Mn}$ during the non-rainfall time and after the rainfalls. The monitoring result indicated that the concentration of SS was the highest in downstream after the rainfalls. We have collected the samples two times after the rainfalls. The rainfall intensity in first sampling was two times higher than second sampling. TN and TP concentrations were increased with increasing the rainfall intensity at all stream. The ESB (Ecological Score of Benthic macroinverterbrate community) index was used to evaluate the statement of stream. ESB results were identified that the upstream is protected waters and the down and midstream is reformed waters. EBS analysis results indicated that the Seoho watershed was ${\beta}$-mesosaprobic at all stream.