• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.135-141
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• 2016

This study investigated changes of hydrology, soil characteristics, riparian vegetation communities, and geomorphology in sandbars before and after sand-mining to determine the effect of sand-mining at upstream of Guemgang and Bochungcheon streams in Korea. Sand-mining events affected the mining area. They supplied organic matters and nutrients during flood. Sediment deposition caused soil texture change and expansion of vegetation area. However, riverbeds were stabilized after the disturbance. According to the analyses of aerial photographs, the vegetation area was significantly expanded in both dam-regulated streams and dam-unregulated streams after sand-mining. Willow shrubs advanced in disturbed area at an average of 10 years after sand-mining. It took willows trees 10.6 years to become dominant communities. Therefore, it took a total of 20.6 years for new riparian forest to form in sandbar after sand-mining. Our results confirmed that stream flow condition were dependent on vegetation recruitment in dam-regulated streams and dam-unregulated streams. For willow recruitment in unregulated streams, calculation of water level below dimensionless bed shear stress is important because low water level variation is a limiting factor of vegetation recruitment.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.93-107
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• 2008

Recently, there have been many projects regarding restoration of streams to recover their environmental and ecological functions. For the restoration of streams, it is valuable academically and economically to evaluate the ecological condition of streams and build a plan and an object for restoring streams based on that. On the other hand, one of the methods to figure out the ecological condition of streams is to evaluate the hydromorphological structure of stream. In this study we have developed a field survey system using the stream assessment methode of LAWA (Laenderarbeitsgemeinschaft Wasser in Germany) that can assess the hydromorphological structure of small and medium streams. In addition, we constructed a GIS-based stream assesment system which can support auto mapping system and report writing, using the survey results. These systems are aimed to help people in the area of restoring streams perceive the natural and ecological condition of streams in the process of making plans and managing the projects, and they also try to help in collecting raw data to determine an ideal potential model to which an existing stream should be turned.

• Journal of Korea Water Resources Association
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• v.47 no.7
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• pp.657-670
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• 2014

We researched the vegetation restoration of 5 urban streams Mugeo-choen, Yaksa-choen, Yeocheon-choen, Myeongjeong-choen and Cheokgwa-choen in Ulsan established as nature-friendly streams by improving water quality and river environment. Ecological restoration effects have resulted from the establishment of streams, which involved supplying sufficient maintenance water for each streams, eliminating the covered sections, preventing the inflow of wastewater, doing vegetation composition, since 5 to 10 years ago. The vegetation inhabitations were compared according to the conditions of physical characteristics and water quality, inland and foreland. In the Cheokgwa-cheon, which is almost a natural river, the ecological integrity of the vegetation population has been maintained quite well. The Mugeo-cheon and the Meongjeong-cheon have cleanly shown the vegetation restoration effects resulting from supplying sustainable maintenance water and wastewater treatments. In the Yaksa-cheon and the Yeocheon-cheon, on the other hand, the vegetation restoration effects and inhabitations were low due to the inflow of wastewater and sledges in some part of stream though the improvement of water quality.

• Journal of Korea Spatial Information System Society
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• v.10 no.2
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• pp.25-33
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• 2008

The aim of this research was to track the appropriate path favorable to urban development when finding small streams which had been destroyed during the process of urbanization and restoring the streams to a natural flow. This research located the targeted streams in the urban area by using GIS, and designated 3 main factors in restoring small streams: altitude, the usage of land, and land prices. After analyzing the possibilities and outcomes of each factor, the study found the most suitable remedy reflecting those 3 factors. Since there are various effects on stream restoration, based on these 3 factors, the study found and used the most viable factor in accordance with its importance. Using this template, the study developed a method to track the most appropriate restoration path. The study results will contribute to finding, and the restoration of disappeared streams for making more pleasant urban life and an environmentally-friendly city.

• Environmental Engineering Research
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• v.13 no.3
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• pp.119-124
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• 2008

Ammonia is an inorganic compound that may cause severe odor problem. In this study the effectiveness of applying natural neutralizer to destroy and remove the odor-causing compound from gas streams was studied. Experimental result evaluated with a bench-scale apparatus via the neutralization of gas phase. This indicates that the natural neutralization depends on the gas concentration, gas residence time, temperature and pH. Removal efficiency of ammonia from gas stream was achieved by 95% using theconvection in the packed bed. This study proved the chemical neutralization technology was effective for controlling inorganic odor-causing compound.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.04a
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• pp.102-107
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• 2010

• Journal of Environmental Impact Assessment
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• v.12 no.4
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• pp.259-270
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• 2003

To investigate the water quality and the pollution state of lower Yeongsan river system, 38 water samples were taken from the main stream of the Yeongsan river, Gomakwon and Hampyeong streams of the system in dry and flood seasons, May and August, 2001. The Yeongsan river is typically natural in accordance with pH-& diagram. But the chemistry based on Piper's diagram indicates that the river is influenced by seawater. BOD increases as the sampling sites are approaching the downstream in Gomakwon and Hampyeong streams overwhelming WQS V grade of 12.40mg/l. T-N and T-P of the river are mainly loaded not in above branch streams but in the main stream of the river, which are caused by manure for farming, domestic animal discharges and life-sewage, in possible. Meanwhile, heavy metal contents are below WQS or not detect in whole water samples. So, it shows that the above river waters be polluted by not industrial but life/agricultural foul waters.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.107-115
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• 2010

This study was surveyed to identify changes of flora during three years after restoration in Cheonggyecheon stream. There are four sections in Cheonggyecheon. One and two sections are upper streams and three and four sections are down streams. It was surveyed 328 species in 2006. In 2007 and 2008, 446 and 444 species were found, respectively. This result shows that Cheonggyecheon is unstable initial condition in restored stream ecosystem. Naturalized species were 58 species in 2006 and it was respectively 61 and 63 species in 2007 and 2008. Hazard species of ecosystem were three common species during survey period. In appearance of flora per section, three and four sections constituted by natural sites such as point bars, wide flood plains, riffles and ponds, marshes, etc. were surveyed more species than one and two constructed by concrete materials and narrow flow channel. Recently, as time goes by, introduced species are being increased. And succession has mainly been progressed by one year or binary herbs and perennial herbs. Compared with other restored streams, Cheonggyecheon showed more flora than Yangjaecheon and Anyangcheon. It is judged owing to length of surveyed site, various planted species and area of inhabitation space. To manage restored stream ecosystem, monitoring is essential. Further, because change of vegetation after restoration in Cheonggyecheon is very important, continuous monitoring about Flora and Naturalized species and Hazard species of ecosystem is also very important.

• Journal of Environmental Science International
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• v.28 no.6
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• pp.535-544
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• 2019

We computed parameters that affect velocity distribution by applying Chiu's two-dimensional velocity distribution equation based on the theory of entropy probability and acoustic doppler current profiler (ADCP) of Jungmun-stream, Akgeun-stream, and Yeonoe-stream among the nine streams in Jeju Province between July 2011 and June 2015. In addition, velocity and flow were calculated using a surface image velocimeter to evaluate the parameters estimated in the velocity observation section of the streams. The mean error rate of flow based on ADCP velocity data was 16.01% with flow calculated using the conventional depth-averaged velocity conversion factor (0.85), 6.02% with flow calculated using the surface velocity and mean velocity regression factor, and 4.58% with flow calculated using Chiu's two-dimensional velocity distribution equation. If surface velocity by a non-contact velocimeter is calculated as mean velocity, the error rate increases for large streams in the inland areas of Korea. Therefore, flow can be calculated precisely by utilizing the velocity distribution equation that accounts for stream flow characteristics and velocity distribution, instead of the conventional depth-averaged conversion factor (0.85).

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.1-6
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• 2022

Among the 13 species of otters in the world, only one Eurasian otter (Lutra lutra) is found in South Korea. In the Korean Peninsula, otter pelts were historically valuable and expensive commodities used for international trade, and otters have long been poached as hunting animals. Recent rapid economic development in South Korea has increased habitat fragmentation and loss, creating a continuing threat to the natural environment. Otters live only in the area of rivers and streams as a family group and are territorial (linear habitat). Due to these limited conditions of otter habitat, the population size of otter is lower than that of onshore mammals. According to recent research, DNA analyses using microsatellite markers have shown that only approximately 7-21 otter individuals inhabit river systems for a length of 50-230 km. Korea's urban streams are associated with many threats that hinder otters from inhabiting them. Many areas around the urban streams are surrounded by high concrete riverbanks, and the risk of roadkill is also high. Nevertheless, ecological restoration projects in the urban rivers will contribute greatly to the stable inhabitation of otters. Detailed otter conservation strategies, such as the elimination of threat factors, improvement of habitat environment, and restoration of food resources and shelter, will provide a positive restoration effect on otter and river ecosystems as well.