• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.5
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• pp.1-7
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• 2013

The objective of this research was to experimentally test the effect of tillage methods on the reduction of runoff, non-point source (NPS) pollution load, sediment and discharge under a rainfall simulation. We used the runoff plots of $5m{\times}30m$ ($L{\times}W$) in size. Experimental treatments were conventional tillage (CT), CT-rice straw bundle (CT-RSB) and two no-till (NT) plots; slope of 3 % or 8 % ; and rainfall intensity of 30 mm/hr. The rainfall simulation was conducted to three times. The time to initial runoff from NT plots was less than that from CT plots regardless of the slope and it was delayed about 65~90 % compared to that of CT plot. And sediment discharge of 8 % slope reduced to 55 % compared to CT plot. But the sediment discharge was not occurred at 3 % slope. The NT and CT-RSB methods have a great possibility of reducing runoff and NPS pollution loads. Runoff rate of NT plots was significantly lower than those of CT plot. The average NPS pollution loads of the NT plots and CT-RSB plot reduced about 55~80 % and 2.1~40 % compared to those of the CT plots, respectively. It was also shown that runoff and NPS pollution loads reduction by NT method could be very significant and contribute to improve the water quality of streams in agricultural regions. It was concluded that the use of NT method on agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem.

• Journal of Korean Society for Geospatial Information Science
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• v.6 no.1 s.11
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• pp.75-90
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• 1998

In this study, as a method for management of waterquality in stream, we build a database on a environmental information such as a pollution source, a waterquality. And especially, we simulate the BOD concentration which is a index indicate the status of organic pollution in stream. Also This study purposes not only building a database on all sorts of envirnomental data, but also searching, statistic and analysis of the database. The result of this study enables us to see and understand contamination state in stream esaily, so it can help to enhance the attention. Also, we can quickly know study area and the degree of effects when water contamination occurs abruptly. And also, we can compare and know pollution source state and the pollutant load among districts. It is expected to use it as an auxiliary basis when we make a policy about pollutant load reduction, because we can know the extent of the pollution in strean by each a pollution source.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.21-28
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• 2013

The objective of the study was to investigate the effect of rice straw mat, rice straw mat with PAM (Polyacrylamide) and gypsum addition on surface runoff and sediment discharge in field. Six experimental plots of $5{\times}22m$ in size and 3 % in slope prepared on gravelly sandy loam soil were treated with control, rice straw mat cover with gypsum and rice straw mat cover with gypsum and PAM. Radish in Spring and Chinese cabbage in autumn growing seasons were cultivated. Non point source (NPS) pollution discharge was monitored and compared among the treatments. Rainfall of the 10 monitored events ranged from 17.0 mm to 93.5 mm. Runoff coefficient of the events was 0.005~0.239 in control plot, 0~0.176 in rice straw plot with gypsum and 0~0.046 in rice straw mat plot with gypsum and PAM. When compared to the control plot, the runoff amount was reduced by 10.4~100 % (Ave. 60.8) in rice straw plot with gypsum and 80.7~100 % (Ave. 96.7 %) in rice straw mat plot with gypsum and PAM. The reduction of NPS pollution load was 54.6 % for BOD5, 71.5 % for SS, 41.6 % for TN and 61.4 % for T-P in rice straw with gypsum plot and 91.9 % for BOD5, 92.0 % for SS, 88.0 % for TN and 88.5 % for T-P in rice straw mat with gypsum and PAM plot. This research revealed that rice straw mat cover with soil amendments on the soil surface could not only increase the crop yield but also reduce the NPS pollution loads substantially.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.469-482
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• 2021

The recent climate change and urbanization have seen an increase in runoff and pollutant loads, and consequently significant negative water pollution. The characteristics of the pollutant loads vary among the different flow regime depending on their source and transport mechanism, However, pollutant load reduction based on flow regime perspectives has not been investigated thoroughly. Therefore, it is necessary to analyze the effects of concentration on pollutant load characteristics and reductions from each flow regime to develop efficient pollution management. As non-point pollutants continuously increase due to the increase in impervious area, efficient management is necessary. Therefore, in this study, 1) the characteristics of pollutant sources were analyzed at the Dalcheon Basin, 2) reduction of nonpoint pollution, and 3) reduction efficiency for flow regimes were analyzed. By analyzing the characteristics of the Dalcheon Basin, a reduction efficiency scenario for each pollutant source was constructed. The efficiency analysis showed 0.06% to 5.62% for the living scenario, 0.09 to 24.62% for the livestock scenario, 0.17% to 12.81% for the industry scenario, 9.45% to 38.45% for the land scenario, and 9.8% to 39.2% for the composite scenario. Therefore, various pollution reduction scenarios, taking into account the characteristics of pollutants and flow regime characteristics, can contribute to the development of efficient measurements to improve water quality at various flow regime perspectives in the Dalcheon Basin.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.572-577
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• 2011

The unit load has simply been used to estimate total pollutant loading from non-point sources, however, it does not count on the variable pollutant loading according to land use characteristics and rainfall intensity. Since pollutant emission from the watershed is strongly dependent on the rainfall intensity, it is necessary to find out the relationship between pollutant loading and rainfall intensity. The objective of this study is to develop simple and easy method to compute non-point source pollution loads with consideration of rainfall intensity. Two non-point source removal facility at Gyeongan-dong (Gwangju-si) and Mohyeon-myeon (Yongin-si), Gyeonggi-do was selected to monitor total rainfall, rainfall intensity, runoff characteristics and water quality from June to November, 2010. Most of Event Mean Concentrations (EMC) of measured water quality data were higher in Gyeongan which has urban land use than in Mohyeon which has rural land use. For the case of TP (Total Phosphorus), Mohyeon has higher values by the influence of larger chemical uses such as fertilizer. The relationship between non-point source pollution load and rainfall intensity is perfectly well explained by cubic regression with 0.33~0.81 coefficients of determination($R^2$). It is expected that the pollution loading function based on the long-term monitoring would be very useful with good accuracy in computing non-point source pollution load, where a rainfall intensity is highly variable.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.59-66
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• 2016

Pollution contribution rate that is effect on water quality from land based load in Masan bay was showed quantifiably for coastal water quality management by using ecological model. It was calculated by difference of water quality concentration at each points t hat is calculated by each scenarios that are presence or absence of each sources (16 points). Results show that, rivers of Northern Masan bay contributed in Masan bay COD is 20 %, T-P is 62 % at northern part and COD is 10 %, T-P is 16 % at middle part. As a result, rivers of Northern Masan bay had effect on water quality of northern Masan bay and middle Masan bay. Also, T-P load affects water quality bigger than COD load, because T-P contribution rate bigger than COD contribution rate of northern rivers. Dukdong WTTP that is land pollution source of southern Masan bay contributed in Masan bay COD is 26 %, T-P is 11% at middle part, COD is 17 %, T-P is 7 % at middle part and COD is 10 %, T-P is 1 % at outer part. It affects water quality bigger at southern and middle of Masan bay than outer bay, because residual flow of bottom flows toward inner of Masan bay nearby Dukdong WTTP.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.935-943
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• 2006

This study focuses on analyzing the inflow characteristic of contaminants of city water that flows into a main water system like a reservoir, and intends to provide basic data which can be efficiently reflected on water quality management policy and decision making of a reservoir. The conclusion obtained from the analysis of the inflow of a main water system by analyzing the inflow property of city water contaminants is as follows. In the case of Chungju-cheon stream which is the city water, pollution load from the basic outflow is low when it rains, and with high load of basic outflow during the dry season, due to the discharge of pollutants from the city, the quality of water becomes worse. In the case of Chungju-cheon stream, average BOD is $4.53mg/{\ell}$ when it rains, and the contaminants increase and flow in about 7.8% compared to the average BOD during the average droughty season. The average SS concentration in water is $798.67mg/{\ell}$ and increased 97.2% compared to the average droughty season.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.161-169
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• 2012

Recently various attempts have been made to apply HSPF model to calculate runoff and diffuse pollution loads of stream and reservoir watersheds. Because the role of standard flow is very important in the water quality modelling of Total Water Pollution Load Management, HSPF was used as a means of estimating standard flow. In this study, BASINS 4.0 and WinHSPF was applied to the Gomakwoncheon watershed, genetic algorithm(GA) and influence coefficient algorithm were used to calibrate the runoff parameters of the WinHSPF. The objective function is the sum of the squares of the normalized residuals of the observed and calculated flow and it is optimized using GA. Estimates of the optimum runoff parameters are made at each iteration of the influence coefficient algorithm. The calibration results showed a relatively good correspondence between the observed and the calculated values. The standard flow(Q275) of the Gomakwoncheon watershed was estimated using the ten years of weather data.

• Journal of Climate Change Research
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• v.5 no.4
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• pp.291-300
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• 2014

In this study, we investigated the activity data and basic data of the surface of the water within the ship to be operated by lakes and rivers inland. In this study previously, there was no survey activity data of Ferry and Cruise ship in Korea. In order to ensure the basic data and development of measures to reduce efficiently by local governments, these studies should be performed. Therefore, in the present study was survey the activity data such as cruising time and engine load factor and the specifications of the vessels. As a result, by analyzing the cruising pattern according to the area and the purpose of the cruise, to calculate the emissions of greenhouse gases.

• Journal of Mechanical Science and Technology
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• v.14 no.4
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• pp.426-432
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• 2000

The development of a low-pollution burner is important for saving energy and preserving the environment. A low-pollution burner can be produced by lean-mixture combustion and general combustion technology. The flammable limit of premixed flame is narrower than that of diffusion flame. Producing a lean mixture of fuel results in an effective combustion condition, which in turn produces high load and low pollution. In this study, it was found that the influx of $Q_2$ had an effect on extending the lean flammable limits and flame stabilization in a doubled jet burner. And the flame, consisting of small eddies, can be stabilized by the nozzle neck phenomena.