• Title/Summary/Keyword: 하천종단

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Characteristics of Channelbed and Woody Debris on Mountainous Stream (산지급류소하천(山地急流小河川)에 있어서 하상미지형(河床微地形)과 유목(流木) 특성(特性))

  • Chun, Kun-Woo;Kim, Min-Sik;Park, Wan-Geun;Ezaki, Tsugio
    • Journal of Korean Society of Forest Science
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    • v.86 no.1
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    • pp.69-79
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    • 1997
  • The purpose of this study is to acquire essential data to reduce the amount of woody debris resulted from the debris flow. This research examined topographic characteristics of the channelbed affecting generation, movement and storage of woody debris and woody characteristics related to number, sizes, shapes, decay, storage direction to mountainous stream. 1. The number of woody debris had a tendency to increase in proportion to stream width, but it was hardly affected by longitudinal gradient of stream. Especially, the greater amount of woody debris was stored at wide section of the stream with compound channel, and it was found in deposits of channelbed rather than in the present channel. 2. Total woody debris over 10cm in diameter and over 2m in length was 402 units and storage number was 35.3 units per 100m of stream. Average diameter of breast height and length were 14cm and 4m, respectively. The woody debris appeared shorter in length and greater in diameter at down-stream than up-stream. 3. Since woody debris met sediments and bed-materials of great roughness in moving, the greater amount of woody debris without root was found in up-stream and down-stream, but deformed woody debris was discovered in upper stream. Decay of woody debris was more severe in down-stream and woody debris on rotting process was found down-stream. 4. Storage direction of woody debris was mainly parallel to center line of stream, and rate of parallel and perpendicularity was 276 and 126 units, respectively. But, as woody debris storing to the perpendicular direction was unstable, the traveling debris could easily be stored. Therefore, some counterplan was required to prevent the traveling woody debris. 5. Tree species of woody debris was mainly larch, which occupied about two third of total woody debris(256 units). The woody debris of larch is easy to move due to hitting of channelbed materials or lower channelbed fluctuation because the lower part of larch is weaker than its upper part. Therefore, the section of the tree species planting in the riparian vegetation needs much more carefulness.

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Distributional Characteristics and Management Device of Naturalized Plants in Naedong Stream, Changwon-si (창원시 내동천의 귀화식물 분포특성과 관리방안)

  • You, Ju-Han;Park, Kyung-Hun;Yoon, Young-Chul
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.4
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    • pp.96-105
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    • 2010
  • The purpose of this study is to offer raw data on managing naturalized plants and the ecological characteristics of urban streams by researching the naturalized plants distributed in Naedong Stream, Changwon-si. The results are as follows. The numbers of naturalized plants were summarized as 45 taxa: 18 families, 38 genera, 43 species and 2 varieties. There were 3 taxa of invasive alien plants: Rumex acetocella, Ambrosia artemisiifolia var. elatior and Sicyos angulaus. In an analysis of life forms, there were 2 taxa of megaphanerophytes, 1 taxa of nanophanerophytes, 3 taxa of chamaiphytes, 7 taxa of hemicryptophytes, 1 taxa of geophytes and 31 taxa of therophytes. The urbanized and naturalized indices were 16.6% and 25.1%, respectively. The results of an analysis by vertical structures showed that naturalized plants included 30 taxa upstream, 42 taxa midstream and 32 taxa downstream. For the urbanized index, upstream was 11.1%, 15.5% in midstream and 11.8% in downstream. For the naturalized index, upstream was 21.7%, 33.3% in midstream and 37.2% in downstream. An analysis of crossing structures showed at taxa of 39 naturalized plants on bank. 30 taxa along the riverside and 7 in the water. For the urbanized index, banks were 14.4%, riverside 11.1% and waterside 2.6% while the naturalized index included 30.5% on the banks, 30.6% along the riverside and 20.0% in the water. As regards the management of naturalized plants, because Remex acetocella, Ambrosia artemisiifolia var. elatior and Sicyos angulaus have a negative impact on the ecosystem, they need to be efficiently controlled.

Analysis of Landslide Characteristics in Jeonlabuk-do, Korea (전라북도 지역의 산사태발생 특성분석)

  • Park, Chong-Min;Ma, Ho-Seop;Kang, Won-Seok;Oh, Kyeong-Won;Park, Seong-Hak;Lee, Sung-Jae
    • Journal of agriculture & life science
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    • v.44 no.4
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    • pp.9-20
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    • 2010
  • This study was carried out to analyze the landslide characteristics and forest environment factors on the landslide area of Jeonlabuk-do province in korea. The results obtained from this study were summarized as follows; The total number of landslide occurrence was 182 areas. The average area of landslide scar was $1,859m^2$, average length of the landslides was 139m, average width was 13m. The landslides were highly occurred in igneous rock and coniferous. And also, slope gradient was $21{\sim}30^{\circ}$, aspect was NE, altitude was 401~500m, vertical and cross slope was concave (凹),stream order was 1 order, soil depth was 15m below, landslide type was linear, forest type was artificial. The relationship between landslide area and environmental factors was a positive correlation with cross slope (convex), position (upper), altitude (501m), forest type (coniferous), parent rock (sedimentary rock), D.B.H. (over 17cm), but was negative correlation with slope gradient ($31{\sim}40^{\circ}$), parent rock (igneous rock), D.B.H. (6~16cm).

Improvement of Small Wetland and Stream in Cultivated Area in point of Landscape Ecology (경작지 내 소규모 습지 및 소하천의 경관생태적 개선방안)

  • Cho, Hyun-Ju;Ra, Jung-Hwa;Kim, Jin-Hyo
    • Current Research on Agriculture and Life Sciences
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    • v.29
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    • pp.11-19
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    • 2011
  • This research gives weight to establish practical improvement based on analysis of the landscape ecological character and value to realize the importance of small wetland and stream in cultivated areas functioning as a residual landscape element in rural landscape and to deal with ecological depression effectively. The results of summary are as follows. 1) The results of landscape ecological character analysis of wetlands biotop in total of 7 sites, for example, size of surface in site 5 was widely formed about $10,600m^2$, which was assessed satisfactory in terms of slope of waterfront, width of hedgerow, vegetation condition of composition and so on. Also, The number of flexibility showed 2 in site 8-1, the highest, and morphological diversity showed 1.47, the highest. 2) The results of problem analysis of wetland biotop, most of wetlands are analyzed that the width of hedgerow was below 1m. Also, the 4 wetlands in site 8 are appeared that hard to live slope vegetation in there because of slope of waterfronts are above $45^{\circ}$. 3) The results of landscape ecological character analysis of stream in total of 6 sites, for example, width of waterfront in site 4 showed 55m, the widest, and investigated consist of natural ingredients such as soil, rock, gravel. However, width of waterfront in site 2-2 showed 4m, the narrowest, and inclined angle of slope was formed a right angle. 4) The results of problem analysis of stream, width of waterfront hedgerow in site 2-1 showed about 5m, which was very narrower than width of waterfront, and toxic chemicals discharged from near cultivated area without any filtering. Also, all areas of site 2-2 was formed concrete, and was assessed dissatisfactory in terms of capacity of nature purification, flood control, habitat living space because of straight stream. 5) Based on the result above landscape ecological character and problem analysis, main improvement guidelines are set in terms of shape, vegetation, topography in case of wetlands, and which are set in terms of vertical, horizontal structure in case of stream.

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