• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.786-795
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• 2012

Water quality management should be focused on the pollution concentrated area so that the improvement of water quality can be achieved effectively for the management of Total Maximum Daily Loads (TMDLs). It is necessary to consider discharge characteristics in the TMDL plan. This study analysed discharge characteristics such as pollution generation and discharge load density, and reduction potential by each unit watershed, and categorized the unit watershed into four groups according to its discharge load characteristics. This analysis can be used as helpful information for the prioritization of pollution reduction area and selection of pollution reduction measures in the development of TMDL plans.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.333-338
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• 2004

This study was carried out to investigate the generation and discharge characteristics of non-point pollutants from farmlands in Nak-dong river basin. Annual unit generation load of nitrogen and phosphorus by fertilization in the test paddy field was almost similar to those calculated by the fertilization standards of district agricultural technology center, but it was extremely higher in case of the test dry field. By comparing annual total generation load of nutrients from fertilization to the data of fertilizer marketing, the accurate forecasting of generation load of pollutants was achieved by marketing data. The annual total discharge ratio of nutrients through infiltration and overflow from the farmland of the test paddy field were 9.5% and 1.1%, respectively, and those in the test dry field were 22.0% and 0.1%, respectively. The monthly discharge load of nutrients were shown the highest proportioned to the discharge load from lands, but it showed higher in phosphorus, which was caused by the intermittent discharge of phosphorus accumulated in drainage.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.3
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• pp.109-121
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• 2020

Converting the agricultural land-use of rice field to upland has been increasingly conducted as farmers encourages themselves to grow higher value-added crops on rice fields under the policy support. Comparing to rice field, Upland shows different characteristic of discharge due to the slope, scale, and shape of field and characteristics of rainfall event. In this study, we designed the experiment fields reflecting flat-upland characteristics with different land scale, and tried to collect the discharge and load data. Soybeans and corn were selected as target crops considering the possibility of large-scale cultivation and crop demand. The cultivation was conducted during the growth period in 2019 with 3 different field scales. Hence, we have collected the discharge data from 17 rainfall events and the load data for 8 rainfall events. As a result, the magnitude of rainfall events and the discharge duration were found to have a strong positive correlation and field discharge occurred during the period by 55% to 83% of rainfall duration. Besides we found other relationships and characteristics of rainfall event, discharge, and pollutant load and also pointed out that continuous monitoring and more data are required to derive statistically significant results. Compared with slope-field monitoring data obtained from the precedent research, the runoff ratio of the flat-fields was significantly lower than slope-fields. Overall the discharge in the slop and flat-fields shows appreciably different characteristics so that the related researches need to be further conducted to reasonably assess environmental impact of agricultural activities at flat-field.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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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.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.739-746
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• 1999

Discharge characteristics of organic materials and nutrients were estimated in the catchment area of relaimed area-Saemankeum-. Discharge load of BOD5 was high in the domestic system, while nitrogen and phosphorous were discharged mainly from the livestock system and the land . Load was so dependent on the precipitation that it increased in the rainy season, particulary in nitrogen and phosphorus. Loads from nonpoint sources in this area were higher compared with others.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.83-89
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• 2013

In order to reduce the power consumption in international standard IEC62087, the luminance efficiency should be improved at the low discharge load rather than at the high discharge load. Thus, this paper analysed the characteristics of the discharge at the panels with ITO Gap of $65{\mu}m$, $80{\mu}m$, and $100{\mu}m$ in 50-inch PDP with FHD resolution. It was well known that the long gap panel improves the luminance and the luminous efficiency. However, it is very difficult to drive the panel due to high driving voltage. When the normal driving method was applied at the panel with ITO gap of $100{\mu}m$, the phenomenon of the double peak was generated in the sustain period. We confirmed that main factor of the double peak is the self-erasing discharge. When the CLHS driving method was applied at the panel with ITO gap of $100{\mu}m$, the self-erasing discharge was improved in the sustain period. Also, the $V_S$ and $V_A$ minimum voltage of the CLHS driving method decreased about 9V and 12V compared with those of the normal driving method. Moreover, when the CLHS driving method was applied to the panel with ITO gap of $100{\mu}m$, the luminance and the luminous efficiency increased compared with those of the normal driving method. The luminance and the luminous efficiency greatly increased at the low discharge load. The less discharge load, the higher increase rate of the luminance and the luminous efficiency. Especially, the luminous efficiency at ITO gap of $100{\mu}m$ increased about 26.3% at the discharge load of 4% compared with that at ITO gap of $65{\mu}m$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.99-105
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• 2010

This paper discussed the theoretical simulation results for developing the blumlein pulsed power source and showed the circuit configuration and the discharge characteristics of the realistic manufactured pulsed power system. In the simulation, the output voltage characteristics at a load resistor showed the general impulse shape when the impedance of a single coaxial cable is matched with the that of a load resistor. In addition, it is confirmed that output values of the pulsed power can be easily controlled by the duplication of coaxial cables and the pulsed waveform showed the general impulse characteristics. Specifically, the inception discharge voltage in the gap distance of 5[mm] between needle and plane electrodes is about 20[kV] and which is lower than about 29[kV] in 9[mm] due to the difference of the reaching time of the inception voltage. Therefore, this paper showed that the output voltage of the blumlein pulsed power source can be easily controlled.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.1
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• pp.90-97
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• 1996

In Korea, total sediment discharge of a river has been estimated simply by using certain sediment transport formulas including, among others, Einstein's formula. Those formular, however, are known not to be reliable enough for the result calculated by them to be used directly to river planning and management. Therefore, the study used the Modified Einstein Procedure to the estimation of total sediment discharge, because this method is reliable estimated by measurement. Here, measurement of sediment discharge used depth integrating method. The major results obtained from the study for estimation by depth integrating method of sediment discharge in Naeseong stream are as follow; 1 The sedeiment characteristics of Naeseong stream are; The distribution of sediment grain size shows that silt and clay are 55% and sand is 45%. and the bed load sediment grain size is constituted that sand contained with the grain size from O.062mm to 2.0mm is 80% 2. The sediment rating formulas derived from the regression analysis between the sediment discharge and flow discharge are; Seogpo-Gyo : Qs=$0.017 \times 10^{-4} Q^{2.352}$, where discharge is l0cms $0.074 \times 10^{-4} Q^{2.066}$, where discharge is l0cms

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.367-377
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• 2014

Paldang lake which is the most important water resource in Korea is classified as a stream type reservoir and water quality of Paldang lake can be significantly influenced by external pollutant source. So this study was aimed to determine focused control BOD and TP sources of each unit watershed upper Paldang lake through analysis of pollutant source distribution and pollutant runoff characteristics. Generated load, discharge load, delivery load and each load density of 11 unit watersheds upper Paldang lake were calculated using data of water quality and flow rate from pollutant sources and 74 small streams. As a result of generated load, discharge load and delivery load of BOD and TP from pollutant sources, the most BOD generated load was taken by livestock with 66% of total BOD discharge load and domestic had the most BOD discharge load, 42.7%. The ratio of delivery load of livestock and domestic was 36.4% and 34.3%, respectively. Livestock occupied high ratio of TP generated load, discharge load and delivery load with 82.5%, 44.4% and 46.7%, respectively. Gyeongan watershed which had high population density showed the highest BOD delivery load density of $14.6kg/km^2/d$ and the highest TP delivery load density with $1.23kg/km^2/d$ was analyzed in Cheongmi watershed including the biggest number of livestock. From these results, management of domestic sewer and livestock excrement was determined as a focused control pollutant source. And intensive management about domestic sewer in Gyeongan stream and livestock excrement in Cheongmi stream is required for water quality improvement of Paldang lake.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.700-714
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• 2015

The characteristic of the water quality and pollutant discharge was analyzed at the units watershed of the total amount management in Han-river basin, and after classified in a similar area by multivariate statistical analysis, the main trend such as the water quality trend and pollutant discharge characteristic were analyzed. As a result of this study, the density of the pollutant at the unit watershed is not necessarily identified as discharge density, and the primary management watershed and targeted substances were analyzed depending on the operating status of the environmental infrastructure in watershed and the main pollution factor and discharge path per pollutants. As a result of cluster analysis, watersheds were classified into four groups according to discharge characteristics. It will be used when selecting target area of primary management that is appropriate to the characteristics of each river and establishing efficient water quality improvement plans.