• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.4
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• pp.11-23
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• 2011

Mountain streams, which are major components of an entire river network, play an important role as the source of water, sediment, coarse and fine organic matter, and nutrients for lowland rivers. Therefore, dynamics and downstream linkages of each compartment of the mountain stream can be essential for watershed management in catchment scale. The dynamics and downstream linkages are understood as a development of step-pool sequences along a river course. Recently, stream restoration after flooding event often employ the development of step-pool sequences in the world. In this paper, we 1) examined the geomorphic characteristics and the role of step-pool sequences in steep mountain streams by reviewing the results of past studies, and 2) introduced the case studies of stream restoration using step-pool sequences, and finally 3) addressed design methods considering geometry and stability of artificial step-pool sequences for stream restoration. Step-pool sequences play an important role not only as roughness with energy dissipation but also as heterogeneity of stream feature for aquatic habitat. Step-pool sequences, even if they are constructed artificially along a stream, may be effective for small stream restoration considering eco-friendly torrent controls. So far the artificial step-pool sequences were employed for mountainous streams, but those would be applied to urban stream.

• Journal of Environmental Science International
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• v.14 no.8
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• pp.739-748
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• 2005

The purpose of this study is to analyze seasonal changes in structure and landscape of Gongji stream corridor in Chuncheon, and to suggest some guidelines to contribute to creating a desirable close-to- nature stream. The study seasonally surveyed floodplain and revetment conditions, channel micro-topography, streamflow level and velocity, and vegetational cover. Flooding, water level, and vegetation were major factors of affecting seasonal changes in streambed structure and stream landscape. Small sand bars and islands were considerably disturbed by flooding and water level change. However, large islands and sand bars in the upper and middle section of the study stream remained or reappeared even after flooding. Flooding also tended to repeat channel sedimentation at the same spot. Controlling water volume of the Euiam Lake, which is adjacent to the study stream, caused higher water level downstream in the dry seasons. The majority of vegetation in sand bars and islands was washed away by the floods. Vehicle passing, crop cultivation, and ball game were other elements which disturbed vegetation in the floodplain. Creating a close-to-nature stream should reflect micro-topographical changes of channel by flooding, prevent improper vehicle entry and human use, and remove concrete material in the revetment and floodplain.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.14-19
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• 2005

Instream flow is necessary to manage the basic function of the rivers. The evaluation method of instream flow in a big river has been studied widely, However, the study in a small river hasn't researched. In theses days the environmental function of a river becomes very important. The evaluation method and secure of instream flow are basic conditions to perform it. Especially view of stream, recreation, protection of ecology are highly demanded in a urban according to the multipurpose of river spaces. Methods for determining the instream flow in the stream were explored and examined through careful reviews and evaluations of available literatures. Development of the instream flow estimation method is based on the reviewed results and methods which can be used within the acceptable levels.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.144-154
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• 2019

The flora of naturalized plants in historic sites, urban parks and stream of Gyeongju-si, South Korea were summarized as 84 taxa including 21 families, 59 genera, 78 species, 1 subspecies, and 5 varieties. Direct investigation was conducted in a historic site with 68 taxa, a neighborhood park with 43 taxa, a stream with 59 taxa and a small park with 42 taxa at 86 sites. Among them, 31.0% (Naturalized Degree (ND) 3) was common but not abundant, 29.8% (ND 5) was common and an abundant plant, 20.2% (ND 2) was local and not an abundant plant. 7 taxa such as Lactuca scariola, Symphyotrichum pilosum, Rumex acetosella were invasive alien species. Lactuca scariola was the most abundant with 41.9%, Symphyotrichum pilosum was more abundant around stream with 34.9%, and Rumex acetosella was abundant on historic sites or small park with 25.6% in all the surveyed sites. To prevent spread of invasive alien species, monitoring may be required, especially, in early settlement stage. A proper management plan needs to be incorporated through physical removal of those plants, substitution of soil and so on.

• Journal of Korea Water Resources Association
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• v.39 no.11 s.172
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• pp.915-922
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• 2006

National Emergency Management Agency is planning a flood disaster mitigation system in urban area. This research is about analysis of runoff reduction efficiency of the alloted detention system which is one of flood disaster mitigation systems in urban area. The alloted detention system is composed of small to middle size detention facilities located in up and middle stream of urban basin. To analyze runoff reduction efficiency of alloted detention system, basic runoff analysis in test area has been carried out and runoff characteristics with size and locations of detention facilities has been simulated. The results of simulation are showing that alloted detention system can reduce the discharge of main stream and detention facilities' size and locations are major parameters of runoff reduction efficiency. It is concluded that alloted detention system can be a useful method in urban area's flood disaster mitigation and can secure safety against flood damages in urban areas.

• Journal of Environmental Impact Assessment
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• v.13 no.4
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• pp.153-164
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• 2004

An integration study of time-variable small watershed and stream models (USEPA's SWMM and WASP5) was performed for impact assessment of urbanization on water environment. The study area, the Kyoungan Stream, the tributary of Paldang Lake, was divided into 111 subbasins, based on the topographic condition, land use, and drainage system. RUNOFF block of SWMM was applied to estimate runoff flow and quality. EXTRAN block computed daily and hourly flow according to simulated runoff flow, water supply, and drainage data. SWMM was connected to WASP5 by transforming output file of SWMM into input file of WASP5. The nonpoint source loads and flow data of SWMM were imported to WASP5. The stream was divided into 45 segments based on the watershed delineation. The study included three water quality parameters, BOD, TN, and TP. The validate models were used to examine the impact of urbanization on stream flow and water quality.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.536-539
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• 2003

The Dongjung Au-Ag-Cu mine area was seriously contaminated with As and heavy metals-Cd, Cu, Hg, Mn, Pb and Zn etc. Those elements were highly accumulated in plants grown at farmland as well as farmland soil. Stream waters and groundwater which has been used as drinking water around the mine site contain high levels of heavy metals, especially As. As a result of human health risk assessment using EHS(Extraction of Heavy metals in Stomach and Small intestine) test for bioaccessible contents of heavy metals, there is a potential of cancer and adverse effects on human health for the residents of the mine area.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.468-480
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• 2007

The urbanization is altering the hydrology, water quality, channel form of waterway and changing the composition of biological communities in the aquatic ecosystem. Recently, towns grew bigger by the drift of large numbers of people and the medium and small leather and dyeing industries around the Pocheon and Youngpyeong streams. The discharges of sewage were increased by them. The UII (urban intensity index) was 85 (st. P-3) and 91 (st. P-6) in the Pocheon stream and about 20 in the Youngpyeong stream. A total 141 taxa of epilithic diatoms which were composed of 2 order, 8 family, 30 genera. Dominant species were Navicula saprophila, N. subminuscula, Nitzschia palea, Gomphonema pseudoaugur in the Pocheon stream and Achnanthes alteragracillima, A. convergens, A. minutissima, N. minima, N. fonticola, N. frustulum and Cymbella minuta var. silesiaca in the Youngpyeong stream. It Showed the different composition of dominant species by the urbanization near two streams. In the relationships between UII and environmental factors such as EC, BOD, COD, TN, TP and DAIpo, UII showed the high relations $(r^2>0.8)$. It was the difference of organic pollution according to urbanization. It therefore, was higher the relative abundance and more the numbers of saprophilous taxa in the Pocheon stream than the Youngpyeong stream. The water quality of two streams by biological indicators(DAIpo) was polysaprobic state(st. P-3, P-4, P-5) in the Pocheon stream and was oligosaprobic (Y-1), mesosaprobic (Y-2, 3) and polysaprobic state (Y-4) in the Youngpyeong stream during the investigation periods.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.691-697
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• 2014

Though the upper stream basin area of Gwanpyung-Cheon in Daejeon, Korea is protected as Green Belt Zone, the stream is under constant environmental pressure due to current agricultural practices and infrastructure development in its basin area. To develop appropriate integrated water resources management plan for the stream, it is necessary to consider not only water quality problems but also water quantity aspect. In this study, Storm Water Management Model (SWMM) was calibrated and validated with sets of field measurements to predict for future water flow and water quality conditions for any rainfall event. While flow modeling results showed good agreement by showing correlation coefficient is greater than 0.9, water quality modeling results showed relatively less accurate levels of agreements with correlation coefficient between 0.67 and 0.87. Hypothetical basin development scenarios were developed to compare effect on stream water quality and quantity when Low Impact Development (LID) technologies are applied in the basin. The results of this study can be used effectively in decision making processes of urban development Gwanpyung-Cheon area by comparing basin management alternatives such as LID methods.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.211-214
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• 2007

The purpose of this study was to establish the basic information for natural drainage capacity assessment in urban area. We sorted midium watershed of Han river and Nak-dong river, and selected 30 rainfall events during 1995 to 2000 according to high level of damage. The inundated area showed high watershed slope about 25% and it indicated the greatest damage around the watershed located in 200-300m of altitude. Besides, the great damage by inundation was occurred in the mountainous agriculture region, where the forest scale was high and the urbanization was being progressed gradually. However, inundated area was small in case of grassland, water tone such as riparian area, bare ground and wetland. Moreover, the inundated area was different according to river shape and characteristics of river distribution such as the density of the stream order, conservation constant of the river system, and the number of undulations in the watershed. Therefore, it showed that land use, river shape and distribution characteristics of stream influence on inundation.