• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.349-357
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• 2006

Nowadays, the discharges of urban streams during dry season are depleted because the hydrologic cycle in the watershed has been destroyed due to the expansion of the impermeable area, the excessive groundwater pumping, climate change, and so forth. The streamflow depletion may bring out severe water quality problems. This research are to investigate the hydrologic characteristics and to develop a technology to restore sound hydrologic cycle of Anyangcheon watershed. For the hydrological cycle analysis of the Anyangcheon watershed, continuous simulations of urban runoff were performed for the upstream basin of Gocheok bridge whose basin area covered 4/5 of the whole catchment area. The increase of impervious area by urbanization was analysed and its effect on urban runoff was evaluated. The SWMM 5 (Storm Water Management Model 5) was used for the continuous simulation of urban runoff. The analysis results of urbanization effect on runoff are as follows: the surface runoff in 2000 increases to 65% of the whole precipitation whereas the surface runoff in 1975 amounts to 50% of the precipitation; the groundwater runoff in 2000 amounts to 7% and shows 6% decrease during the period from 1975 to 2000.

• Solar Energy
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• v.6 no.1
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• pp.47-59
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• 1986

This paper presents the establishment of optimum design conditions and economic evaluation for solar hot water system. The aim of this study is to present thermal performance of solar heating systems and to determine their performance as a function of collector size, storage capacity, tilting of collector and other factors. By analyzing its performance under the various conditions, optimum design of solar heating system can be obtained. System performance are obtained monthly and yearly basis respectively. At the same time the economics of various systems are evaluated. For the computer simulation Mokpo, Kangnung, Chupungnyong and Seoul are selected for particular installation places. As a result, the optimal design condition of solar heating system considering the following factors such as installation angle of collector, capacity of storage tank, collector size in each place can be obtained as follows; (1) Installation angle of collector Tilt = lattitude (2) Capacity of storage tank Solar domestic hot water system : $45\;1/m^2$ Multifamily solar domestic hot water system : $35\;1/m^2$ (3) Collector size i) Solar domestic hot water system Seoul & Chupyungyong area : $11.52\;m^2$ Mokpo area : $8.64\;m^2$ ii) Multifamily solar domestic hot water system Seoul, Chupyungyong & Mokpo area : $345.6\;m^2$ Kangnung area : $259.2\;m^2$

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.285-289
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• 2004

Oceanographic observation and qualitative analysis for deep ocean water in the East Sea were carried out from January 2003 to January 2004, in order to understand the characteristics of deep sea water in the East Sea. Temporal and spatial variation of water masses were discussed from survey of the study area including the coastal sea of Kwangwon province in where the polar front mixing cold and warm water masses were formed. On the basis of the vertical profiles of temperature, salinity and dissolved oxygen, water masses in the study area were divided into 5 major groups; (1) Low Saline Surface Water (LSSW) (2) Tsushima Surface water (TSW) (3) Tsushima Middle Water (TMW) (4) North Korea Cold Water (NKCW) and (5) East Sea Proper Water (ESPW). In winter, surface water in coastal sea of Kwangwaan Kosung region were dominated by North Korean Cold Water (NKCW). As Tsushima warm current were enforced in summer, various water masses were vertically emerged in study area, in order of TSW, TMW, NKCW and ESPW. It is highly possible that the LSSW which occurred at surface water of september is originated from influx of fresh water due to the seasonal rainy spell. Nevertheless water masses existed within surface water were seasonally varied, water quality characteristics of East Sea Proper Water (ESPW) under 300 m did not changed all the seasons of the year.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.125-132
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• 2012

Saemangeum development project is the world's largest tidal flat reclamation project. It is currently under construction, and proceeding with phased developments. The construction of agricultural areas within the Saemangeum reclamed lands is also a part of this project. These areas will have multi-functional complexes aiming to produce mainly eco-friendly horticultural crops and livestock products for the purpose of export. The major concern is to obtain sufficient water with appropriate quality to supply to those areas. The objective of this study is therefore to provide available water supply plans for agricultural purpose, especially for horticulture and livestock complexes. Alternative methods for water supply are purifying water from the Saemangenm lake or using water supply services providing by K-water or local governments. This study investigates to find an economical water supply plan through comparisons of these methods. As a result, the water purification method with Saemangeum lake water could be advantageous for given water supply conditions to horticulture and livestock complexes.

• Journal of Korea Water Resources Association
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• v.42 no.8
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• pp.631-641
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• 2009

Transport of nitrous oxide and treated waste water was investigated in an estuary receiving treated waste water. Seasonal change of water quality were also observed to assure origins of $N_2O$ and to estimate the influence of treated waste water on $N_2O$ production in the survey area. Based on nitrous oxide concentration profiles in the survey area, discharged treated waste water were traced, which flowed upstream at the flood tide and downstream at the ebb tide with concentration maxima. It is assumed that nitrous oxide discharged from treated waste water is transported to the survey area with partial and vertical mixture. To determine the production of $N_2O$ in survey area, flux at each sampling sites were calculated and 25% of the produced $N_2O$ was originated from treated waste water in result. The remaining percentage of the production was also assumed to be the discharge from the sediment layers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.335-340
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• 2006

Geology and terrain of Imha basin has a very weak characteristics to soil erosion, so much soil particles flow into Imha reservoir and bring about high density turbid water when it rains a lot. Especially, since the agricultural area of Imha basin is mainly located in river boundary, Imha reservoir has suffered from turbid water by soil erosion. Therefore, it is important to estimate the influence of soil erosion to establish efficient management of water-pollutant buffering zone for the reduction of turbid water. By applying GIS-based RUSLE model, this study can acquire 12.23% that is the ratio of soil erosion in water-pollutant buffering zone and is higher than area-ratio (9.95%) of water-pollutant buffering zone. This is why the area-ratio of agricultural district (27.24%) in water-pollutant buffering zone is higher than the area-ratio of agricultural district (14.96%) in Imha basin. Also as the result of soil erosion in sub-basin, Daegok basin shows highest soil erosion in water-pollutant buffering zone, second is Banbyeon_10 basin and last is Seosi basin.

• The Korean Journal of Ecology
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• v.21 no.2
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• pp.125-131
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• 1998

Histological damage and growth inhibition of Pinus densiflora were analysed in different areas around the Metropolitan area of Seoul urban (heavily polluted), suburban (lightly polluted), and rural(unpolluted) areas. Soil properties of each area were also investigated. Contact angles of water droplet on needle leaves growing in polluted areas were lower than that in unpolluted area. Transpiration rates of needle leaves growing in polluted areas were more rapid than that in unpolluted area. These results represented that needle leaves growing in polluted areas were more susceptible to water deficit than that growing in unpolluted area was. Growths of annual ring of Pinus densiflora growing in polluted areas were lower than that in unpolluted area. On the other hand, soil pH in polluted areas was lower than that in unpolluted area. That is, the former was more acidified than that the latter was. Ca and Mg contents in polluted areas were lower than that in unpolluted area, while Al contents in polluted areas were higher than that in unpolluted area. These soil properties revealed that the effects of acid precipitates in urban and suburban areas were severer than that in rural area.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.1-10
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• 2013

Major issues in water supply service have changed from expansion of service area to improvement of service quality, i.e., water quality and safety, and early response to emergency situation. This change in the service concept triggers the perceptions of limitation with the current centralized water supply system and of necessities of decentralized (distributed) water supply system (DWSS), which can make up the limitations. DWSS can reduce the possibility of water supply outage by establishing multiple barriers such as emergency water supply system, and secure better water quality by locating treatment facilities neighboring consumers. On the other hand, fluctuation of water demand will be increased due to the reduced supply area, which makes difficult to promptly respond the fluctuating demand. In order to supplement this, hybrid water supply system was proposed, which combined DWSS with conventional water supply system using distributing reservoir to secure the stability of water supply. The Optimal connection point of DWSS to existing water supply network in urban area was determined by simulating a supply network using EPANET. Optimal location of decentralized water treatment plant (or connection point) is a nodal point where changes in pressure at other nodal points can be minimized. At the same time, the optimal point should be selected to minimize hydraulic retention time in supply network (water age) to secure proper water quality. In order to locate the point where these two criteria are satisfied optimally, Distance measure method, one of multi-criteria decision making was employed to integrate the two results having different dimensions. This methodology can be used as an efficient decision-support criterion for the location of treatment plant in decentralized water supply system.

• Journal of Environmental Impact Assessment
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• v.8 no.3
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• pp.13-22
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• 1999

Tidal flow and water quality were simulated in this paper to assess environmental impact caused by pier construction projects in Onsan harbor system. The Surfacewater Modeling System (SMS) was applied to the Onsan harbor system, where coastal reclamation and dredging were planned to build the piers. A finite element mesh was constructed and refined to cover the complicated geometry of the Onsan harbor and the proposed reclamation area. The time variable change of tidal height at harbor inlet was given as an input condition to tidal simulation. The water quality simulation was based on the discharge rate of suspended solids at the reclamation area. The simulation results have shown reasonable agreements with real situations in both tidal flow and water quality. According to the proposed plan, tidal flow and water quality were predicted during and after the pier construction. The tidal simulation study showed that there would be no discernible change of tidal current in the harbor except for the dredged area. The water quality simulation, however, predicted that suspended solids would increase significantly near the reclaimed and dredged areas during construction.

• Journal of the korean society of oceanography
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• v.34 no.3
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• pp.151-166
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• 1999

Both benthic and planktonic foraminifera from Core 97-02 obtained in the northern East China Sea are quantitatively analyzed for reconstructing the paleocenography of late Quaternary. Since the earliest time of the core sediment (last not older than 18000 yr B.P.), the paleo-water depth has changed from less than 20 m to near 100 m at present, which is reflected by the benthic foraminiferal assemblages: before 14000 yr B.P., the water depth was shallower than 20 m; from 14000 to 7500 yr B.P., water depth was 20-50 m; and after 7500 yr B.P., water depth was 50-100 m. The foraminiferal fauna also disclose the water mass history: during the last glacial maximum, the water that dominated the study area might be the coastal water; at the end of the last glacial maximum(14000-9500 yr B.P.), the Yellow Sea Cold Water mostly affected this area; then it gave way to the Yellow Sea Warm Current after 9500 yr B.P.; and finally, the warm water has dominated this area since 9500 yr B.P. because of the westward shift and enhancement of the Kuroshio Current.