• 환경영향평가
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• 제21권3호
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• pp.339-352
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• 2012

Total maximum daily load have been implemented and indicated that nonpoint discharge coeffients in flow duration curve were 0.50 of Normal flow duration ($Q_{185}$) and 0.15 of low flow duration($Q_{275}$). By using SWAT, nonpoint discharge coefficients are studied with the conditions of the instream flow and the rainfall in two study areas. The nonpoint discharge coefficient average of BOD and TP for normal flows duration in 3 years are 0.32~0.36 and 0.28~0.31. For the low flow duration, the nonpoint discharge coefficient avergae of BOD and TP were 0.10~0.12 and 0.10~0.11. These are lower than the coefficients of total maximum load regulation. There are big differences between one of regulation and one of SWAT for the normal flow duration. With the consideration of rainfall condition, the nonpoint discharge coefficient of flood flow duration are influenced on the amount of rainfalls. However, the nonpoint discharge coefficients of normal flow duration and low flow duration are not effected by the rainfall condition. Since the spatial distribution and geomorphological characteristics could be considered with SWAT, the estimation of nonpoint discharge coefficient in watershed model is better method than the use of the recommended number in the regulation.

• 한국물환경학회지
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• 제24권4호
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• pp.452-457
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• 2008

Nonpoint source (NPS) pollution is caused by rainfall moving over and through the ground. As the runoff moves, it picks up and carries away various pollutants from NPS. The discharge pattern of NPS pollutant loads is affected by the distribution of the rainfall during the year. This study analysed relationship between the rainfall event and the stream flow rate, and estimated the rainfall discharge ratio on the specific design flow which can be used as nonpoint discharge coefficient for the estimation of NPS pollution load. It is considered that nonpoint discharge coefficient can be effectively used for the calculation of NPS pollution load at the time of water quality modelling for the management of Total maximum daily load (TMDL).

• 한국농공학회논문집
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• 제57권1호
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• pp.89-97
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• 2015

This study is to assess the effect of non-point source pollution discharge loads between tillage and no-tillage applications for upland crop areas using SWAT (Soil and Water Assessment Tool) watershed modeling. For Byulmi-cheon small rural catchment ($1.17km^2$) located in upstream of Gyeongan-cheon watershed, the rainfall, discharge and stream water quality have been monitored in the catchment outlet since 2011. The SWAT model was calibrated and validated in hourly basis using 19 rainfall events during 2011-2013. The average Nash-Sutcliffe model efficiency and $R^2$ (determination coefficient) for streamflow were 0.67 and 0.79 respectively. Using the 10 % surface runoff reduction from experiment results for no-tillage condition in field plots of 3 % and 8 % slopes under sesami cultivation, the soil saturated hydraulic conductivity for upland crop areas was adjusted from 0.001 mm/hr to 0.0025 mm/hr in average. Under the condition, the catchment sediment, T-N (total nitrogen, TN), and T-P (total phosphorus, TP) discharge loads were reduced by 6.9 %, 7.4 %, and 7.7 % respectively.

• 한국물환경학회지
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• 제31권6호
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• pp.653-664
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• 2015

TPLMS (Total water pollutant load management system) that is the most powerful water-quality protection program have been implemented since 2004. In the implementation of TPLMS, target water-quality and permissible discharged load from each unit watershed can be decided by water-quality modeling. And NPS (Non-point sources) discharge coefficients associated with certain (standard) flow are used on estimation of input data for model. National Institute of Environmental Research (NIER) recommend NPS discharge coefficients as 0.15 (Q₂₇₅) and 0.50 (Q₁₈₅) in common for whole watershed in Korea. But, uniform coefficient is difficult to reflect various NPS characteristics of individual watershed. Monthly NPS discharge coefficients were predicted and estimated using surface flow and water-quality from HSPF watershed model in this study. Those coefficients were plotted in flow duration curve of study area (Palger stream and Geumho C watershed) with monthly average flow. Linear regression analysis was performed about NPS discharge coefficients of BOD, T-N and T-P associated with flow, and R² of regression were distributed in 0.893~0.930 (Palger stream) and 0.939~0.959 (Geumho C). NPS Discharge coefficient through regression can be estimated flexibly according to flow, and be considered characteristics of watershed with watershed model.

• 농업과학연구
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• 제26권2호
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• pp.61-69
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• 1999

1. 방동저수지 상류 5개 토지이용별 유출수량과 수질조사를 실시하고 비점오염원 원단위를 산정 하였다. 산지에서 SS 84kg/ha/년, BOD 4.2kg/ha/년, COD 15kg/ha/년, T-P 0.1kg/ha/년, T-N 1.1kg/ha/년으로 배출부하원단위가 가장 작았다. 거주지역에서 SS 319kg/ha/년, BOD 34kg/ha/년, COD 98kg/ha/년, T-P 5.6kg/ha/년, T-N 8.7kg/ha/년으로 배출부하 원단위가 가장 많았다. 2. 비점오염원은 강우-유출과 관련이 있어 전체 비점오염원의 약 46%가 7~8월에 유출되며, 건기인 10월에서 4월까지는 연간 총량의 약20%, 5월에서 9월까지는 약80%가 유출된다. 3. 유기물질인 SS, BOD, COD는 거주지역에서, 영양물질인 T-N은 논 밭지역에서 T-P는 논 밭 거주지역 및 방목지에서 많이 유출되고 있다. 4. T-N, T-P 등 영양물질이 농지에서 많이 유출되어 저수지와 같은 폐쇄수역에 부영양화로 인한 수질악화의 원인이 된다. 비점오염원이 우기에 집중배출되어 공공수역에 큰 오염원으로 작용하므로 도시하천을 이용한 비점오염원 관리방안과 비점오염원 발생원 저감방안을 적극 추진하여야 한다.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2007년도 GIS 공동춘계학술대회 논문집
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• pp.246-251
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• 2007

The purpose of this study is to develop a grid based model for calculating the critical nonpoint source (NPS) pollution load (BOD, TN, TP) in Nak-dong area in South Korea. In the last two decades, NPS pollution has become a topic for research that resulted in the development of numerous modeling techniques. Watershed researchers need to be able to emphasis on the characterization of water quality, including NPS pollution loads estimates. Geographic Information System (GIS) has been designed for the assessment of NPS pollution in a watershed. It uses different data such as DEM, precipitation, stream network, discharge, and land use data sets and utilizes a grid representation of a watershed for the approximation of average annual pollution loads and concentrations. The difficulty in traditional NPS modeling is the problem of identifying sources and quantifying the loads. This research is intended to investigate the correlation of NPS pollution concentrations with land uses in a watershed by calculating Expected Mean Concentrations (EMC). This work was accomplished using a grid based modelling technique that encompasses three stages. The first step includes estimating runoff grid by means of the precipitation grid and runoff coefficient. The second step is deriving the gird based model for calculating NPS pollution loads. The last step is validating the gird based model with traditional pollution loads calculation by applying statistical t-test method. The results on real data, illustrate the merits of the grid based modelling approach. Therefore, this model investigates a method of estimating and simulating point loads along with the spatially distributed NPS pollution loads. The pollutant concentration from local runoff is supposed to be directly related to land use in the region and is not considered to vary from event to event or within areas of similar land uses. By consideration of this point, it is anticipated that a single mean estimated pollutant concentration is assigned to all land uses rather than taking into account unique concentrations for different soil types, crops, and so on.

• 대한환경공학회지
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• 제30권5호
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• pp.567-573
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• 2008

달천의 하도내에서 종횡단의 수질조사 및 하천특성에 대한 분석을 수행하였으며, 주요 지점을 중심으로 유량변화에 따른 수질변화를 검토하였다. 강우의 발생으로 유량이 증가한 경우에 BOD의 농도는 감소하였으며, TN과 TP의 농도는 증가한 것으로 나타났다. 유량이 증가하였던 Case 2에서 BOD, TN, TP는 모두 유속과 수심에 대하여 큰 상관계수를 보였다. 강우가 비점오염원의 유입을 유도하여 하도내 수질변화에 많은 영향을 미치고 있는 것으로 분석되었다. 하도내의 유속은 수치모형(SMS)을 통해서 분석할 수 있었으며, 경사가 크고, 하도의 폭이 좁은 상류 구간에서 비교적 유속이 큰 것으로 나타났다. 2차원 하도내에서 오염원의 거동특성이 모의되었으며, 주수로인 흐름의 중앙부분으로 오염원이 빠르게 확산되는 것으로 나타났다. 오염 확산은 흐름에 큰 영향을 받고 있는 것으로 모의되었다.

• 한국농공학회논문집
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• 제53권2호
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• pp.67-74
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• 2011

This research focused on the investigation of runoff and nonpoint sources (NPS) pollution characteristics from small soil box plots treated by livestock waste composts. An indoor rainfall simulation was performed over the plots for 60 minutes. Simulated rainfall intensities were 32.4, 43.2, 50.3 and 57.1 mm/hr respectively. Slope of soil box plots was $10^{\circ}$ and $20^{\circ}$, respectively. Rainfall simulation replicated 5 times and the experiment was conducted every four days five times. As the slope of soil box increased, NPS pollution loads increased. And as rainfall intensity was increased from 32.4 to 57.1 mm/hr, NPS pollution loads gradually increased, too. Discharge of NPS pollution loads was the largest in the first simulation and thereafter decreased gradually. Discharged BOD load to the total applied load from $10^{\circ}$ plots, ranged 0.2 to 0.7 %, was 8.4 to 50.0 % lower than slope $20^{\circ}$ plots. When the application rate increased twice, the increase of pollution load was between 1.7~5.7 times. Analysis of Pearson's correlation coefficient showed that organic matter content in pig compost and NPS pollution loads were correlated well. While under liquid compost application, the correlation coefficients between them were not good. It was concluded that application of livestock resources need to consider long-term weather forecast and if necessary, NPS reduction measures must be preceded in order to reduce NPS pollution discharge.

• 환경영향평가
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• 제21권6호
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• pp.917-925
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• 2012

In this study, we report the runoff characteristics of pollutants for Tamjin A and B watershed in Tamjin river basin using statistical analysis, such as correlation analysis and regression equation. Flow rate and water qualtiy data collected from 2 sampling sites(Tamjin A and B watershed) during 3 years(2009~2011) were analyzed for biochemical oxygen demand(BOD), total nitorgen(TN), total phosphorus(TP) and suspended solid(SS). The results showed that strong correlations were observed between flow rate and SS in Tamjin A, while weak correlations were observed among the BOD, TN, and TP. In Tamjin B, strong correlations were observed among the flow rate, SS and T-P except BOD and TP. Meanwhile, the values of $R^2$ for regression equations between flow rate and pollutants load were greater than 0.7. Results of these statistics indicated that there was a good agreement between flow rate and pollutants load. Also, the flow rate exponents of regression equations for BOD, TN, and TP were smaller than 1 in Tamjin A. In Tamjin B, flow rate exponents of regression equation for BOD and TP were smaller than 1. These results indicated that concentrations of BOD, TN, TP in Tamjin A and concentrations of BOD and TP were decreased as the flow rate was increased. This means that rater than nonpoint sources, point sources affect BOD, TN and TP in Tamjin A and BOD and TP in Tamjin B.