• Journal of the Korean association of regional geographers
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• v.12 no.3
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• pp.352-363
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• 2006

The purpose of this paper is to analyze changes in the depositional landform in the channel of Cha-cheon, a branch stream of Nakdong river(main stream) since the artificial straight channel has been constructed in 1973. The results of analyses are as follow. First, the Cha-cheon has flooded over one time in a year, and flowed backward over three times annually, according to analyze the data of the Hyeonpoong Gauging Station of rainfall and water level during a decade(1993$\sim$2002). Second, the flood plain within the artificial straightened channel has a nearly plain profile between the small dike and last riffle(point A). Deposits thickness of flood plain reduce gradually toward upstream. Third, grain size distribution of the flood plain deposits(0$\sim$20cm) within the artificial straightened channel has a coarsening trend in downstream reach of C point. It implies that the backward flow of Nakdong river(the main stream of Cha-cheon) make effect on the depositional mechanism of lowest reach in Cha-cheon. Finally, the result of analyzing grain size distribution of the flood plain deposits(0$\sim$20cm) within the artificial straightened channel implies that the c-point is the boundary between the vertical deposition of suspended load due to the backward flow of Nakdong river and the deposition of bed load supplied from hillslope of Cha-cheon basin.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.4
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• pp.39-49
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• 1999

Urban streams have, recently, been straightened and widened to alleviate flooding problem. As a result, the stream have been modified inadvertently for ecological functions and microtopography. In this study, we investigated riparian vegetation and microtopography of the tributaries of Han River before and after the monsoon rain in summer. The purpose of this study was to relate the stream microtopography to the distribution of riparian vegetation. The stream microtopography was investigated for its scale and pattern. Vegetation was investigated from 131 plots by Braun-Blanquet method. The distribution of riparian vegetation was significantly correlated with the stream microtopography. Various herbaceous species occurred at stream bank slop, high terrace and channel side. However, at channel side and concave part of terrace where soils were in high moisture level, only a few wetland species were dominated. The complexity of the microtopography in the stream corridors led to heterogeneous riparian vegetation. The vegetation showed more stability against flooding at the stream corridors with natural and complex microtopography than at the urban-type stream corridors with simple topographical features. The results showed that the development of riparian vegetation was influenced by the changes in microtopography, which was primarily determined by the shape and characteristics of channel. It seemed that a close-to-nature river system would be restored more readily with an understanding of microtopographical features affecting the distribution of riparian vegetation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.1-8
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• 2007

The Anyang River which located in an urban area near Seoul had been managed focusing on supplying home and industrial water and preventing floods, coping with rapid industrialization and urbanization. Consequently, it was changed into a deadly river during 25 years. Its channel was straightened by concrete and water quality deteriorated to BOD 190mg/l. In addition, water quantity has been rapidly decreased and has been drying up. Also, as the river ecosystem, landscape, water-friendly function, and so forth were seriously deteriorated, people turn away from the urban river. From 2001, the master plan under the 10-year has been actively carried out centering on the preceding items, which are healthy river in which fishes inhabit, safe river free from floods and droughts, and pleasant river where citizens visit. As a result, its water quality was remarkably improved by BOD 5mg/l in 2005 and some upper zones were improved enough to allow people to swim. Moreover, various animals including fish and birds gather around the river. Now, the 'Anyang River Restoration Project' is recognized as the first comprehensive and systematic nature-friendly urban river improvement in Korea.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.566-569
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• 2004

This study is to trace the change of stream shape using the past series of aerial photographs, and to compare the land use changes of riparian area along the stream. For the Gyeongan national stream, aerial photographs of 1966, 1981 and 2000 were selected and ortho photographs were made with interior orientation and exterior orientation, respectively. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream widths were widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974. The land use maps (1966, 1981,2000) of riparian areas were also made, respectively and classified into 6 categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing. The area of forest and agricultural land decreased and urban area increased as the stream maintenance was performed.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.458-462
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• 2004

This study is to trace the change of stream shape using the past series of aerial photographs and compare the land use changes of inland along the stream. For the Gyeong-an national stream, aerial photographs of 1966, 1981 and 2000 was selected and ortho photograph was made with RMSE of 1.05, 0.54, 0.72 pixels, respectively. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream width widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.3 s.116
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• pp.1-11
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• 2006

This study analyzed characteristics of natural and human environments in Chuncheon's Gongji stream, and suggested nature-friendly planning strategies for self-purification of water quality, biodiversity improvement and conservative waterfront recreation. The environmental analysis included streambed structures, floodplain soils, water quality, vegetation, wildlife, and human facilities. Natural colonization of vegetation for the middle section of the study stream was obstructed by a straightened concrete revetment of baseflow channel, and vehicle movement and concrete parking lots across the floodplain. These human disturbances also deteriorated the naturalness of the stream landscape and limited habitation of bird species. However, natural sedimented wetlands in half of the channel width for the lower section of the stream contributed to a desirable vegetational landscape and greater bird occurrence. Based on BOD measurements, water quality of the stream fell under class $II{\sim}III$ of the stream water-quality standard, but it was worse around sewage outlets due to incomplete sewage collection especially during the dry season. Dominant fish species included typical inhabitants of good water-quality streams that are tolerant of adverse habitat changes. Nature-friendly planning strategies were established based on analysis of the environmental characteristics. They focused on not merely spatial zoning and layout divided into four zones - preservation, partial preservation, conservation and use -, but close-to-nature channel revetment techniques, natural water-purification facilities, biotope diversification, and water-friendly recreation and circulation. Strategies pursued both renewal of stream naturalness and hydraulic stability of streamflow by minimizing transformation of natural channel micro-topography and biotope, and by reflecting natural traces of streambed structures such as revetment scour and sedimentation.

• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.379-390
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• 2005

This study is to trace the change of stream shape using the past series of aortal photographs and topographic maps, and to compare the land use changes of inland along the stream. For the Gyeongan first & second class of local stream, aerial photographs of 1966, 1981 and 2000 were selected and ortho photographs were made with interior orientation and exterior orientation, respectively. In addition, topographic maps of 1914 - 1915 were used to compare with stream of 1966, 1981 and 2000. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream width widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974. The land use maps (1966, 1981, 2000) of riparian areas were also made, respectively and classified into 6 categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing, The main changes of land use were agricultural land, urban area, road and sandbar.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.167-176
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• 2015

The water quality of the Gulpo Stream flowing through Incheon, Bucheon, Seoul, and Kimpo is getting worse due to a slow flow rate and bank constructions by stream channelization as well as an inflow of pollutants from living-sewages and factory-sewages. Besides, a dry stream phenomenon caused by a lack of maintenance water upstream makes a self-purification system worse, and the water quality of the Gulpo Stream is currently at its lowest level. The accumulated sludge of the streambed is mostly formed by the deposition of particle pollutants due to the slow flow rate and an artificially straightened stream channel. This accumulated sludge adsorbs a great quantity of organic materials and heavy metals. Because of the internal contamination possibility by a re-gushing, even after the pollution source is removed, it can cause future water pollution. Without a total examination as previously recommended, it is considered difficult to accomplish practical efficiency. In conclusion, the management of periodic sediment management such as dredging would be necessary in the Gulpo Stream because sediment could be an internal pollution source of stream water under anaerobic conditions.