• Membrane and Water Treatment
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• v.10 no.1
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• pp.99-104
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• 2019

In Korea, nonpoint pollutants have a significant effect on rivers' water quality, and they are discharged in very different ways depending on rainfall events. Therefore, preparing an optimal countermeasure against nonpoint pollutants requires much monitoring. The present study was conducted to help prepare a method for installing an automatic nonpoint pollutant measurement system for the cost-effective monitoring of the effect of nonpoint pollutants on rivers. In the present study, monitoring was performed at six sites of a river passing through an urban area with a basin area of $454.3km^2$. The results showed that monitoring could be performed for a relatively long time interval in the upstream and downstream regions, which are mainly comprised of forests, regardless of the rainfall amount. On the contrary, in the urban region, the monitoring had to be performed at a relatively short time interval each time when the rainfall intensity changed. This was because the flow rate was significantly dependent on the rainfall's intensity. The appropriate sites for installing an automatic measurement system were found to be a site before entering the urban region, a site after passing through the urban region, and the end of a river where the effects of nonpoint pollutant sources can be well-decided. The analysis also showed that the monitoring time should be longer for the rainfall events of a higher rainfall class and for the sites closer to the river end. This is because the rainfall runoff has a longer effect on the river. However, the effect of nonpoint pollutant sources was not significantly different between the upstream and the downstream in the cases of rainfall events over 100 mm.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.665-681
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• 2012

This study investigates the influence of anthropogenic heat (AH) release on urban boundary layer in the Gyeong-In region using the Weather Research and Forecasting model that includes the Seoul National University Urban Canopy Model (SNUUCM). The gridded AH emission data, which is estimated in the Gyeong-In region in 2002 based on the energy consumption statistics data, are implemented into the SNUUCM. The simulated air temperature and wind speed show good agreement with the observed ones particularly in terms of phase for 11 urban sites, but they are overestimated in the nighttime. It is found that the influence of AH release on air temperature is larger in the nighttime than in the daytime even though the AH intensity is larger in the daytime. As compared with the results with AH release and without AH release, the contribution of AH release on urban heat island intensity is large in the nighttime and in the morning. As the AH intensity increases, the water vapor mixing ratio decreases in the daytime but increases in the nighttime. The atmospheric boundary layer height increases greatly in the morning (0800 - 1100 LST) and midnight (0000 LST). These results indicate that AH release can have an impact on weather and air quality in urban areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1100-1101
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• 2005

• Journal of environmental and Sanitary engineering
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• v.1 no.1 s.1
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• pp.97-107
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• 1986

This study was performed to investigate the air pollution tolerance of urban trees; Gingko biloba, Platanus occidentalis, Salix pseudolagiogyne and Purunus serrulata growing in Seoul, Taegu, Chungju area. Vitality of trees and water soluble sulfur content in the leaves were determined at 24 points in those cities. The ratio of the each number of Platanus occidentalis, Gingko biloba, Salix psuedolagiogyne and Prunus serrulata to the total number of urban tree in Seoul area was $49.38\%,\; 17.36\%,\; 13.42\%,\;2.43\%$, respectively. Its ratio in Taegu area was $36.76\%,\;14.25\%,\;13.36\%,\;3.32\%$ and in the Chungju area was $59.06\%,\;17.35\%,\;11.09\%,\;8.33\%$, respectively. The species deversity was 0.7017, 09067, 0.5297 in Seoul, Taegu, Chungju, respectively. The significant correlation between the S02 concentration and the tree vitality highly found on Platanus occidentalis, Gingko biloba, Salix pseudolagiogyne and Prunus serrulata. Positive correlation coefficient between $SO_2$ concentration and water soluble sulfur content were shown on Platanus occidentalis, Salix pseudolagiogyne and Prunus serrulata and that between tree vitality and water soluble sulfur content were shown on Platanus occidentalis and Gingko biloba. The tolerant to the S02 gas was high in order of Salix pseudolagiogyne, Gingko biloba, Prunus serrulata and Platanus occidentalis. Also the absorption activity to the $SO_2$ gas was high in order of Salix psuedolagiogyne, Gingko biloba, Platanus occidentalis and Prunus serrulata.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.1-8
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• 1999

This study is one of the processes to build the artificial wetlands in the urban area. The purpose of this study was to survey biotic or physical environments, and to review modelling techniques to find out the ecological structure and function. Case study site was the Bangdong wetland in the north west side of Taejon metropolitan city. The number of species of insects decreased during monitoring. But the number of individuals of insects decreased abruptly after increasing. And then biodiversity index dropped and dominance index increased. So the structure of biotopes was affected by weather conditions. And in the restricted area such as urban area, the changes of insects were affected sensitively by not physical but environmental changes. As for birds, the number of species was reduced a little, but the number of individuals increased abruptly. And dominance index increased slowly. The changes of water depth and increase of temperature affected the habitat condition of vegetations and birds, so the dominance index of specific species increased. In urban areas it is necessary to continue management for water environmental changes, such as the depth and area of water. The number of species of fishes was reduced a little, but the number of individuals increased abruptly. And dominance index and biodiversity index decreased slowly. But the water environments was so changeable that it is difficult to explain current status as some specific trends. The number of species of reptiles and amphibians changed little, but the number of individuals increased abruptly. And dominance and biodiversity were not changed. The changes of water depth and temperature affected the habitat of every species the environmental changes affected.

• Structural Engineering and Mechanics
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• v.73 no.3
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• pp.339-351
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• 2020

Earthquakes are natural disasters that cause serious social disruptions and economic losses. In particular, they have a significant impact on critical lifeline infrastructure such as urban water transmission networks. Therefore, it is important to predict network performance and provide an alternative that minimizes the damage by considering the factors affecting lifeline structures. This paper proposes a probabilistic reliability approach for post-hazard flow analysis of a water transmission network according to earthquake magnitude, pipeline deterioration, and interdependency between pumping plants and 154 kV substations. The model is composed of the following three phases: (1) generation of input ground motion considering spatial correlation, (2) updating the revised nodal demands, and (3) calculation of available nodal demands. Accordingly, a computer code was developed to perform the hydraulic analysis and numerical modelling of water facilities. For numerical simulation, an actual water transmission network was considered and the epicenter was determined from historical earthquake data. To evaluate the network performance, flow-based performance indicators such as system serviceability, nodal serviceability, and mean normal status rate were introduced. The results from the proposed approach quantitatively show that the water network is significantly affected by not only the magnitude of the earthquake but the interdependency and pipeline deterioration.

• 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.

• Hwankyungkyoyuk
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• v.20 no.2
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• pp.78-92
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• 2007

The purindicator and its application through the application of the eco-city concept. To achieve this aim, this study execute to erect eco-city concept, to develop urban evaluation indicator for the fifth and sixth graders of elementary school, to survey for elementary school teacher in Daegu and to develop application of urban evaluation indicator for the fifth and sixth graders of elementary school. The result of study can be summarized as follow. First, erecting the eco-city concept and urban evaluation indicator for the fifth and sixth graders of elementary school was developed with 14 objects, such like that saving and sound circulation of water resource, sound atmosphere. Second, The result of survey, generally, teachers evaluated that Daegu has problems. The degree of interest of urban environmental problem of Daegu showed that each problem had relatively equal distribution. Teachers had positive response that the ecocity concept applied to environmental education of elementary school. Selection of educational contents had distinct tendency with application of the concept of ecocity. Teachers indicated several problems in environmental education of elementary school. Third, We develop application of indicator for the fifth and sixth graders of elementary school. We concluded that developing application of indicator will offer as follows: First, student and teacher can logically understand urban environmental problems. Second, application of indicator had role of useful tool for environmental education of elementary school.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5330-5336
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• 2011

It becomes more and more important to develop various infiltration facilities for healthy water cycle and reduction of urban storm water runoff. In this study, a infiltration facility by utilizing tree box was developed. The developed facility is capable of reducing storm water road runoff, improving urban water cycle, and performing other sustainable and environmental functions. Because the facility can be manufactured to a smaller size than an existing runoff reduction facility, it can be installed at various road types of not only existing urban areas, but new developed areas. If the facility is applied to four-lane roadways, it is expected to reduce 65% of rainfall runoff discharge. Urban flood control improvement can be accomplished by a wide application of the developed technique.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.747-757
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• 2004

The objectives of this study were to investigate the physical, chemical, and structural characteristics of the stream, especially Mugeo and Yeochon which are being changed to ecological stream by Ulsan city, and to acquire the considerations such as the planning element and plan criteria of the streams for making ecological stream system. Water quality, water quantity, vegetation, in stream structures and facilities, and land usage of the streams were investigated and the build up capabilities of ecological stream for the two streams were also analyzed. Planning elements for restoration to ecological stream included physical and biological purification methods in water quality, short term water acquire alternatives in water quantity, and vegetation recovery plan and improvement of habitation environment in ecological system, respectively. Planing elements in physical structures and facilities also included recovery of concrete levee and removal and recovery of covered channel.