• 한국농공학회지
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• 제22권2호
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• pp.55-63
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• 1980

To study run-off characteristics in the small watersheds in Korea, investigations had been carried out for a period of 4 years from 1972 to 1975 in the sample watersheds. The samples were selected in four major river basins such as the Han River, the Keum River, the Nakdong River and the Yongsan River. Water levels and rainfall data had been. collected from each sample area where the measuring instruments were installed. The findings of this investigation can be summarized as follows; 1. With an average runoff rate of 60% in the sample watersheds, the average runoff rate. in each sample proved to be as below; the Han River Basin : 41.4% the Keum River Basin : 61.7% the Nakdong River Basin : 69.4% the Yong San River Basin : 69.2% 2. The base flow rate in the sample watersheds proved to be 8.1 mm/month. 3. A comparison of the runoff obtained from actual measurements made and that calculated by the Kaijyama formula showed that the latter is 9.1% lower than the former.

• 환경영향평가
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• 제23권1호
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• pp.19-27
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• 2014

The purpose of this study is to provide a base line data to improve the water quality in the Yeongsan River basin. As the major factor that affects the water quality of Yeongsan River is nonpoint pollution source, in order to find a resolve to improve the quality, a study was conducted to identify the correlation between the stream water quality and that of the land use. The study showed that the concentration of the contents in the water from the agricultural land environment was found to be higher as oppose to that found in the content of the water from the forest land. As a result, it can be deducted that agricultural land deteriorates water quality whereas that of the forest land is of much better quality. Therefore, it is highly recommended to take advanced improved care of agricultural land close to a water source to improve the quality of Yeongsan River basin.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2001년도 춘계 학술발표논문집
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• pp.38-38
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• 2001

The rainfall estimates give sufficiently accurate information to map areas which have received the minimum rainfall necessary for outbreaks of pests such as locusts, thus cutting down the cost of searching for likely outbreak sites. At the other end of the scale, satellite rainfall estimates can be used to give timely warnings of changes in river levels and the likelihood of floods in large river catchments.(omitted)

• 한국농공학회지
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• 제44권6호
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• pp.61-70
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• 2002

This study was performed to analyze the river fractal characteristics using GIS (Geographic Information System). In this study, topographical factors in river basin were grid-analyzed for each cell size and scale using GIS and regression formula was derived by analyzing correlation among topographical factors and cell size which were calculated here. And, a new rainfall-runoff model which is considering the calculated fractal dimension was developed to apply fur a river basin.

• 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.734-738
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• 1999

This study is to modify the EUTRO5(sub-model of WASP5) for applying river water quality simulation. Because previous version of EUTRO5 has unique kinetic constant for all segement on each constituent, EUTRO5 is not adequate for some river simulation. As this version have each kinetic constant for all segment on each constituent, it will be suitable for model application with rapid changing geometry and kinetic purification of upstream river.

• 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.47-50
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• 1999

From 1997 irrigation water withdraws has been surveyed for the purpose of river operation and management . Recently , the River Law was revised (1999.2.8) and obligate to water users to report their proposed and actual water withdrawals. If we can save more water from rice paddy area, we can use more water for municipal and industrial activity and we can expect water quality should be improved in the river. So the role of irrigation water use efficiency is more and more important.

• 한국농공학회지
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• 제12권4호
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• pp.2063-2077
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• 1970

The Purpose of this study is to give the hydrologically basic data for the development of water resources in Korea and a quantity of daily average precipitation and its frequency in a year are investigated to study the presumption which is affected to river flow. Characteristics of precipitation is poor as source of water resources compared with its efficiency. So, because of such characteristics of precipitation, river flow also is in harmony and distribution of river flow comes to the result of irregularity, that is, range of river coefficiet between the quantity of maximum river flow and others river flow is big, and it is insufficient as source of water resources. Yearly river flow being expressed by daily unit indicates the ratio(%) of distribution to total yearly river flow, and the model of hydrograph is drawn up. The gives the basis to make yearly water balance sheet. This study is not completed, yet but in forth-coming days, the water will try continuously to give more correct basis for the development of water resources according to a great deal of data.

• Environmental Engineering Research
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• 제22권2호
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• pp.203-209
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• 2017

Innovations in the biofiltration process can provide effective solutions to overcome crucial water pollution problems. The elimination of pollutants is a result of the combined effects of biological oxidation, adsorption and filtration processes. This research aims to evaluate the performance of quartz sand biofiltration for removing total suspended solids, turbidity, color, organic matter, and ammonium from polluted river water and develop an empirical model for designing quartz sand biofilters for the treatment of polluted river water. Experiments were conducted using two biofilter units filled with quartz sand as filter media. A set of experiments were performed to evaluate the effect of hydraulic retention time on biofilter performance in removing water contaminants. The kinetics of organic matter removal were also determined to describe the performance of the biofilter. The results show that biofiltration can significantly remove river water pollutants. Removal efficiency depends on the applied hydraulic retention time. At a hydraulic retention time of two hours, removal efficiencies of total organics, ammonium and total suspended solids were up to 78%, 82%, and 91%, respectively. A model for designing quartz sand biofiltration has been developed from the experimental data.

• 농업과학연구
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• 제50권4호
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• pp.903-916
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• 2023

This study aims to establish basic data for efficient management of rural water by analyzing regional irrigation facilities and benefitted areas in the statistical yearbook of land and water development for agriculture at the watershed level. For 511 domestic rural water use areas, water storage facilities (reservoirs, pumping & drainage stations, intake weirs, infiltration galleries, and tube wells) are spatially distributed, and the benefitted areas provided at the city/county level are divided by water use area to provide agricultural water supply facilities. The characteristics of rural water district areas such as benefitted area, were analyzed by basin. The average area of Korea's 511 rural water districts is 19,638 ha. The average benefitted area by rural water district is 1,270 ha, with the Geum River basin at 2,220 ha and the Yeongsan River basin at 1,868 ha, which is larger than the overall average. The Han River basin at 807 ha, the Nakdong River basin at 1,121 ha, and the Seomjing River basin at 938 ha are smaller than the overall average. The results of this basic analysis are expected to be used to set the direction of various supply and demand management projects that take into account the rational and scientific use and distribution of rural water and the characteristics of water use areas by presenting a quantitative definition of Korea's agricultural water districts.

• 한국농공학회논문집
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• 제61권2호
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• pp.25-39
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• 2019

The water pollution Accident in the South Han River is increasing due to increase of pollutants inflow from small streams from rural areas and reduced flow rate. This study predicted the change of water quality in the main stream of the South Han River due to climate change through the linkage of watershed and water quality models. Also, This study analyzed the effect of water quality improvement on Seomgang and the South Han River by securing the flow during the dry season. According to the scenarios for securing the river flow during drought season, the river flow in the Seomgang is increased up to 2.19 times, and the water quality during the drought season was improved up to $BOD_5$ 20.5%, T-N 40.8%, T-P 53.4%. Also, the water quality of the main stream of the South Han River improved to 5.22% of $BOD_5$, 5.42% of T-N and 7.69% of T-P as the river flow was secured from the Seomgang. The result of this study confirms that securing the baseflow in the Seomgang according to the scenarios for securing the river flow during the dry season has a positive effect on the improvement of the water quality of the rivers in the main river of the Seomgang and South Han River. The results of this study will contribute to the establishment of reasonable management to improve the water quality of the main stream of the Seomgang and South Han River.