• Korean Journal of Environmental Biology
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• 제21권3호
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• pp.223-233
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• 2003

This paper introduces a study on the development of environment assessment technique and biodiversity management system for stream ecosystems and their application to Korean streams. Based on comprehensive field investigations from a series of streams of Bukhangang (North Han River) system as well as on long-term field survey and bibliographic data from streams throughout South Korea, schemes for environmental and biodiversity research of stream ecosystems aye reviewed; types of major environmental damages in Korean streams are classified; a rapid assessment technique for nature quality of stream ecosystems is presented; and a list of environmental and biotic factors for the use of GIS-based biodiversity management system in stream ecosystems is provided. The biodiveysity management system, which is based on ArcView and GEUS programs, is applied to Gapyeong Creek, a typical mid-size stream in Korea.

• Journal of Korean Society on Water Environment
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• 제33권3호
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• pp.273-281
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• 2017

The objective of this study is to evaluate the performance of stream purification equipment system combined MBP (Micro Bubble Process) and AGBP (Aerobic Granular Biofilm Process). Based on results, the optimal HRT (Hydraulic Retention Time) of MBP and AGBP set as 0.72 and 2.4 h, respectively. In the results of continuous operation on combined MBP and AGBP, it is possible to achieve a BOD, TSS and T-P removal efficiency of 85, 90 and 94%, respectively. It also confirmed that the water quality of the stream can be purified with increasing circulation flow through water simulation evaluation applied the QUAL-NIER model. Consequently this purification system can resolve the stream purification and dry stream problem.

• Journal of IKEEE
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• 제7권2호
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• pp.188-196
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• 2003

In this paper, a demultiplexer for MPEG-2 Transport Stream which can be applied to terrestrial digital broadcast is developed. The demultiplexer separates video, audio, and data from MPEG-2 multimedia stream and transports them to each decoders respectively. While most existing demultiplexers of MPEG-2 transport stream have been developed as hardware systems, but the fast increment of computer's performance enables a software demultiplexer to be worked in realtime. The developed demultiplexer is implemented as a software module called a filter using DirectShow of Microsoft which is based on COM(Component Object Model)and works on the Windows system. The operation of the demultiplexer is verified by using the GraphEdit tool and rendering a test file formatted as MPEG-2 transport stream.

• Journal of Environmental Health Sciences
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• 제20권4호
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• pp.17-35
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• 1994

This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)

• Journal of the Korean Institute of Landscape Architecture
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• 제23권3호
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• pp.132-143
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• 1995

Comprehensive development projects were carried out on the Han River from 1982 to 1986 for the purpose of creating a more serviceable places such as a riverside parks and autoroads and so on. However because of the river development, river ecosystem and function were destroyed. And many local autonomous entity follows comprehensive development projects as if it is a model case. To investigate the impact that the river development effects the river ecosystem, two sites which are Anyangcheon and Sooipcheon were surveyed in the right of around plants ecosystem and structure. Two sites are creek of the Hna River. Sooipcheon maintains the sound ecosystem. It has sufficient carrying capacity for the river recreation activity. The reason is that a hydrophyte absorbs nutrients from the stream and the river ecosystem meets the around terrestrial one neturally. Number of hydrophyte increase from upstream going forward to downstream. Number of hydrophyte increase from upstream going forward to downstream. Anyangchoen is seriously polluted stream out of many branch stream of the Han river. In the upstream various woody plants and hydrophyte appeared. But from the river developed area at midstream, naturalized plants dominated such as Bidens tripartita, panicum dichotomiflorum etc. To manage the creek ecologically, hydrophyts were introduced in partly for natural purification after rehavilitate the riverside, and steadily monitoring is demanded.

• Journal of Environmental Impact Assessment
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• 제16권1호
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• pp.59-68
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• 2007

Urban streams have been severely degraded with wastewater and concrete structure over a prolonged period. The Chonggyecheon Restoration Project recovered a stream in the downtown Seoul with landscaping, plantings and bridges after the cover concrete and elevated asphalt road were removed. The project has been criticized partly because it is not an ecological restoration but rather the development of an urban park with an unnaturally straight flowing stream, artificial building structures, and artificial water pumping from the Han River. Nevertheless, the public have praised the project and almost 100,000 visitors per day come to see the reeds, catfish, and ducks. The stream restoration project is attractive to central and regional government decision makers because it increases the public concern of landscape amenity. Several projects such as Sanjichon and Kaeumjungchon are on going and proposed. These projects have a common and different respect in scope and procedure. The Chonggyecheon project in the process of environmental impact assessment (EIA) and prior environmental review system (PERS) reviewed the environmental impacts before development. Kaeumjungchon in the PERS and Sanjichon without EIA and PERS are reviewed. EIA and PERS systems contribute to checking the ecological sustainability of the restoration projects. A stream restoration project is a very complex task, so an integrated approach from plan to project is needed for ecologically sound restoration. Ecological stream restoration requires 1) an assessment of the entire stream ecosystem 2) establishing an ecologically sound management system of the stream reflecting not only benefits for people but also flora and fauna; 3) developing the site-specific design criteria and construction techniques including habitat restoration, flood plains conservation, and fluvial management; 4) considering the stream watershed in land use plan, EIA, PERS, and strategic environmental assessment (SEA). Additionally the process needs to develop the methodologies to enhance stakeholder's participation during planning, construction, and monitoring.

• Journal of Korea Water Resources Association
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• 제43권5호
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• pp.421-431
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• 2010

The hydromorphological structure assessment of the urban streams of Anyang stream, Yangjae stream, Osan stream, Jangsu stream, and Hakui stream 5 years the after close to nature stream restoration work was performed using LAWA (Laenderarbeitsgemeinschaft Wasser) for the investigation of the ecology of streams in urban areas. Based on the results, the effectiveness of stream restoration in urban areas was least in spite that existing various types of stream improvements were applied. Significantly, the grade of the longitudinal, the waterfront, and the use of land nearby waterfront was poorly evaluated. It would be estimated that this trend was due to the discontinuity of the longitudinal, the lack of diversity in waterfront, the installation of facilities nearby waterfront, and was due to the use of hard materials as like stones, blocks, frames, and mats in waterfront. The further studies on the implementation of structural diversity in waterfront should be performed for the improvement of the ecology of urban streams.

• Korean Journal of Environmental Agriculture
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• 제19권5호
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• pp.382-393
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• 2000

The principal indicators contributing to water qualities was screened by factor analyses, based on the monitored chemical parameters of water quality for various water resources from 1995 to 1999 in the small agricultural catchments of the Han River Basin. Water samples of streams, groundwaters, and reservoirs were taken four times a year from upper (Daegwanryong), middle (Dunnae and Chunchon) and lower (Guri) reaches of Han River Basin. In these areas, the respective type of farming practiced was alpine agriculture and livestocks raising, typical upland and paddy cultivation, and intensive cropping in the plastic film house. Water quality was monitored for twenty-one water quality parameters, including pH, EC, SS, T-N, T-P, COD, cations, anions, and heavy metals. pH, EC and COD of the stream waters were suitable for the Korea irrigation water quality guidelines. However, T-N and T-P concentrations of water samples in four catchments far exceeded the irrigation water guideline. Concentrations of canons and heavy metals in Wangsuk stream in Guri area were higher than those in streams in other areas. Factor analysis revealed that significant correlation was observed for 81 pairs out of 231 water quality indicators of stream water among the $21\;{\times}\;21$ cross correlation matrix of stream water quality indicators. The first factor accounted for 27.01% of the total variation in stream water quality indicators, and high positive factor loadings were shown on EC, K, Na, $NH_4\;^+-N$, $PO_4\;^{3-}$, $SO_4\;^{2-}$, and COD. Fifty-three water quality indicator pairs were significant out of 190 ground water quality parameters. The first factor accounted for 28.54% of the total variation in ground water quality indicators, and high loadings were revealed on EC, Ca, Mg, K, Na, $NH_4\;^+-N$, and $SO_4$. Twenty-nine pairs of reservoir water quality indicators were significant out of 66 pairs. The first factor accounted for 37.06% of the total variation in reservoir water quality indicators, and high loadings were shown on EC, Mg, K, Na, SS, T-P, Cl, and COD. These results demonstrate that EC was the first factor contributing to water quality.

• Journal of Korea Water Resources Association
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• 제39권2호
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• pp.151-160
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• 2006

In this study, threshold runoff which is a hydrologic component of flash flood guidance(FFG) is estimated by using Manning's bankfull flow and Geomorphoclimatic Instantaneous Unit Hydrograph(GcIUH) methods on Han River watershed. Geographic Information System(GIS) and 3' Digital Elevation Model database have been used to prepare the basin parameters of a very fine drainage area($1.02\~56.41km^2$), stream length and stream slope for threshold runoff computation. Also, cross-sectional data of basin and stream channel are collected for a statistical analysis of regional regression relationships and then those are used to estimate the stream parameters. The estimated threshold runoff values are ranged from 2 mm/h to 14 mm/6hr on Han River headwater basin with the 1-hour duration values are$97\%$ up to 8mm and the 6-hour values are $98\%$ up to 14mm. The sensitivity analysis shows that threshold runoff is more variative to the stream channel cross-sectional factors such as a stream slope, top width and friction slope than the drainage area. In comparisons between the computed threshold runoffs on this study area and the three other regions in the United States, the computed results on Han River watershed are reasonable.

• Korean Journal of Environment and Ecology
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• 제32권3호
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• pp.261-273
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• 2018

This study investigated the characteristics of fish communities in the streams flowing into the Han river in Seoul in May 2016 through April 2017. The investigated streams were Ui stream, Danghyeon stream, Cheonggye stream, Yangjae stream, Mokgam stream, Dorim stream, and Hongje stream, which were restored to their natural form. We collected 41 species of 10 families using skimming nets and cast nets from 21 points during the investigation period. There were 7 Korean endemic species, or 17.1% in collected species, such as Acheilognathus yamatsutae, Acheilognathus gracilis, Scrcocheilichthys nigripinnis morii, Squalidus japonicus coreanus, Zacco koreanus, Coreoperca herzi, and Odontobutis interruta. There were 5 (12.2%) exotic species: Cyprinus carpio (fancy type), Carassius auratus (goldfish), Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. The dominant species were Zacco platypus, Carassius auratus, Acheilognathus lanceolatus, Acheilognathus gracilis, and Oryzias sinensis. The Yangjae stream showed more stable fish community than other streams as it showed higher species diversity, and evenness and richness indices. Regarding the fish tolerance guild according to water quality, there were 3 (7.3%) sensitive species, 16 (39.0%) intermediate species, and 22 (56.7%) tolerant species. Twelve (29.3%) were insectivore species, 23 (56.1%) were omnivore species, and 6 (14.6%) were carnivore species, indicating the dominating presence of omnivore fish species.