• Title/Summary/Keyword: Topographical Factor

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Potential Soil Loss Prediction for Land Resource Management in the Nakdong River Basin (토지자원관리를 위한 낙동강 유역의 잠재적 토양유실량 산정)

  • Oh, Jeong-Hak;Jung, Sung-Gwan
    • Journal of Korean Society of Rural Planning
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    • v.11 no.2 s.27
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    • pp.9-19
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    • 2005
  • The purpose of this study is to analyze the potential soil loss and hazard zone by the Revised Universal Soil Loss Equation(RUSLE) for preservation and management of land resources which is the base of ecosystem, and to grasp the relationship between RUSLE factors in the Nakdong River Basin. All thematic maps used in RUSLE are constructed through GIS and spatial analysis method derived from digital topographic maps, detailed soil maps, land-cover maps, and mean annual precipitation of 30 years collected respectively from National Geographic Information Institute, National Institute of Agricultural Science and Technology, and Ministry of Environment. The slope length of LS-factor that takes much times by the study area's wideness was calculated automatically through AML(Arc Macro Language) program developed by Van Remortel et al.(2001, 2003). The results are as follows; First, according to the soil loss estimation by the RUSLE, it shows that approximately 82% of the study area have relatively lower possibility of soil loss which is the 1 ton/ha in annual soil loss. While, 9.4% ($2,228km^2$) needed intensive and continuous management for soil loss. Because the amount of their annual soil loss was greater than 10 ton/ha that is optimum level suggested by Morgan(1995). For these areas, the author believe that a new approach which can minimize environmental impacts from soil loss through improvement of cultivation process and buffer forest zone should be applied. Second, according to the relationship between the RUSLE factors, topographical(LS-factor) and cover management(C-factor) conditions have a lot of influence on soil loss in case of the Nakdong River Basin. However, because of RUSLE factor's influence that affect to soil loss might be different based on the variety of spatial hierarchy and extent, it is necessary to analyze and evaluate factor's relationship in terms of spatial hierarchy and extent through field observations and further studies.

Risk Assessment of Soil Erosion in Gyeongju Using RUSLE Method (RUSLE 기법을 이용한 경주지역의 토양침식 위험도 평가)

  • Oh, Jeong-Hak;You, Ju-Han;Kim, Kyung-Tae;Lee, Woo-Sung
    • Journal of Environmental Impact Assessment
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    • v.20 no.3
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    • pp.313-324
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    • 2011
  • The purpose of this study is to present the raw data for establishing the plan of top soil conservation in soil environment and preventing the soil loss by establishing the potential amount of soil loss using RUSLE. The results are as follows. To apply the RUSLE model, we calculated the potential amount of soil loss by using 5 factors; rainfall erosion factor(R), topographical factor(LS), soil erosion factor(K), land cover factor(C) and erosion control factor(P). The assessment map of soil loss was drawn up by classifying 5 grades. According to the soil loss estimation by the RUSLE, it showed that approximately 83.9% of the study area had relatively lower possibility of soil loss which was the 1 ton/ha in annual soil loss. Whereas, the 7.0% of the study area was defined as high risk area which was the 10 ton/ha in annual. Therefore, this area was needed that there was environment-friendly construction of farm land, improvement of cultivation environment and so forth. In future, if we will analyze the amount of soil loss of Gyeongju national park and Hyeongsan river watershed, we will offer the help to establishing the conservation plan of soil environment in Gyeongsangbuk-do.

Improvement Plan of Environment-Impacting Facilities by Inhabitants Consciousness and Spatial Characteristics in Rural Areas (주민의식과 입지특성에 따른 농촌마을 환경영향시설의 정비방향)

  • Kim, Young-Joo;Choi, Soo-Myung
    • Journal of Korean Society of Rural Planning
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    • v.11 no.4 s.29
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    • pp.99-108
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    • 2005
  • In this study, thirteen villages in Chonnam province were selected as case study sites and the spatial distribution of the facilities in the villages was examined to provide basic information fur the establishment of rural plans. According to the questionnaire survey, various problem such as environmental pollution, position, scene, management etc. was brought owing to cattle shed, and dissension was more or less seen by scale of facilities, management of facilities and waste, regional factor(stock farming management condition, life style and attitude of inhabitants) and topographical factor (height, position physical aspect of a mountain, distance with water resources etc.) etc.. The facilities could be classified into 6 types based on the their spatial locations: 1) Type 1, facilities located at the waterside; 2) Type 2, facilities located at the entrance of village; 3) Type 3 facilities, scattered in the residential area: 4) Type 4 facilities, collectivized in village; 5) Type 5 facilities, adjoining village; and 6) Type 6 facilities, scattered irregularly inside and outside of village. Based on the classification, possible implementations for the reduction of environmental impacts were suggested. The results of this study could be used as an example of study on the distribution, classification, and rearrangement of environment-impacting facilities in rural areas for improvement of their roles in providing amenity resources.

PROBABILISTIC LANDSLIDE SUSCEPTIBILITY AND FACTOR EFFECT ANALYSIS

  • LEE SARO;AB TALIB JASMI
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.306-309
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    • 2004
  • The susceptibility of landslides and the effect of landslide-related factors at Penang in Malaysia using the Geographic Information System (GIS) and remote sensing data have been evaluated. Landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys. Topographical and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. The factors chosen that influence landslide occurrence were: topographic slope, topographic aspect, topographic curvature and distance from drainage, all from the topographic database; lithology and distance from lineament, taken from the geologic database; land use from Landsat TM (Thermatic Mapper) satellite images; and the vegetation index value from SPOT HRV (High Resolution Visible) satellite images. Landslide hazardous areas were analysed and mapped using the landslide-occurrence factors employing the probability-frequency ratio method. To assess the effect of these factors, each factor was excluded from the analysis, and its effect verified using the landslide location data. As a result, land 'cover had relatively positive effects, and lithology had relatively negative effects on the landslide susceptibility maps in the study area. In addition, the landslide susceptibility maps using the all factors showed the relatively good results.

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Study on Risk Assesment of Debris Flow using GIS (GIS를 이용한 토석류 위험성 평가에 관한 연구 (소규모 개발지역 중심으로))

  • Chang, In-Soo;Park, Eun-Young;Park, Ki-Bum;Kim, Sungwon
    • Journal of Environmental Science International
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    • v.22 no.2
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    • pp.225-234
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    • 2013
  • The relationship between debris flow and topographical factors is essential for the reliable estimation of soil loss. The objective of this paper is to estimate stability index and soil loss for assessing landsliding risk caused by debris flow. SIMAP and RUSLE are used to estimate stability index and soil loss, respectively. The landsliding risk area estimated by using SIMAP is found to be different from the large land area estimated by RUSLE. It is found that the spatial distribution of soil cover significantly influences landsliding risk area. Results also indicate that stability index and soil loss, estimated by soil cover factor, improve the assessment of landsliding risk.

A Study of Numerical Analysis for Uneven Stress of Tunnel (터널 편압 대책에 대한 수치해석적 연구)

  • 현기환;윤지선
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.501-508
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    • 2000
  • In recent years, as lines are selected In disadvantageous region, unavoidable developments is increased. Owing to such developments. environmental problems have been occurred frequently, In excavation of tunnels especially located in close to slope, uneven stress take place to tunnel due to a topographical factor. it is used assistant methods of construction which are excavation of slope, retaining wall, ground anchor, etc for uneven stress. these assistant methods raise problems of environmental. In this study, using slit, we could make better stress state by means of inducing stress concentration in boundary of tunnel. considering a variety of slit and rock mass condition, we use numerical analysis.

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Analysis of Susceptibility in Landslide Distribution Areas (산사태 발생지역에서의 민감성 분석에 관한 연구)

  • 양인태;유영걸;천기선;전우현
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.11a
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    • pp.381-384
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    • 2004
  • The goal of this study is to generate a landslide susceptibility map using GIS(geographic information system) based method. A simple and efficient algorithm is proposed to generate a landslide susceptibility map from DEM(digital elevation model) and existing maps. The categories of controlling factors for landslides, aspect of slope, soil, topographical index, landuse, vegetation are defined, because those factors are said to have relevance to landslide and are easy to obtain theirs sources. The weight value for landslide susceptibility is calculated from the density of the area of landslide blocks in each class. Finally, a map of susceptibility zones is produced using the weight value of all controlling factors, and then each susceptibility zone is evaluated by comparing with the distribution of each controlling factor class.

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Distribution of growth hormone-releasing factor- and somatostatin-immunoreactive neurons in the hypothalamus of the Korean squirrel(sciurus vulgalis coreae) (청서 시상하부의 growth hormone-releasing factor 및 somatostatin 면역반응신경세포의 분포)

  • Jeong, Young-gil;Son, Hwa-young;Yoon, Won-kee;Kim, Kil-soo;Won, Moo-ho;Ryu, Si-yun;Cho, Sung-whan;Kim, Moo-kang
    • Korean Journal of Veterinary Research
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    • v.35 no.4
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    • pp.671-681
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    • 1995
  • This study was attempted to investigate the topographical distribution, shape and immunoreactivity of growth hormone-releasing factor(GRF)- and somatostatin(SOM)-immunoreactive neurons in the hypothalamus of the Korean squirrels(Sciurus vulgalis coreae). For the light microscopical examination of immunohistochemistry, the brains were fixed with 4% paraformaldehyde solution by means of intracardiac perfusion. And the frozen sections($40{\mu}m$ thick) were stained immunohistochemically by ABC method. Distribution of GRF immunoreactive neurons($12-17{\mu}m$) was highest in the paraventricular nucleus, moderate in the periventricular and supraoptic nuclei, and low in the arcuate nucleus and lateral hypothalamic area. Their immunoreactive fibers were found very high in the median eminence, moderately in the supraoptic, paraventricular and periventricular nuclei, and low in the arcuate nucleus and lateral hypothalamic area. SOM immunoreactive perikarya($14-18{\mu}m$) were found moderately in the periventricular nucleus near the subependymal layer of the third ventricle, and low in the arcuate and suprachiasmatic nuclei. SOM immunoreactive fibers were found high in the median eminence, and moderately or low in the arcuate and periventricular nuclei.

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An Analysis of Observational Environments for Solar Radiation Stations of Korea Meteorological Administration using the Digital Elevation Model and Solar Radiation Model (수치표고모델과 태양복사모델을 이용한 기상청 일사 관측소 관측환경 분석)

  • Jee, Joon-Bum;Zo, Il-Sung;Kim, Bu-Yo;Lee, Kyu-Tae
    • Journal of the Korean earth science society
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    • v.40 no.2
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    • pp.119-134
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    • 2019
  • In order to analyze the observational environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we used the digital elevation model (DEM) and the solar radiation model to calculate a topographical shading, sky view factor (SVF) and solar radiation by surrounding terrain. The sky line and SVF were calculated using high resolution DEM around 25 km of the solar stations. We analyzed the topographic effect by analyzing overlapped solar map with sky line. Particularly, Incheon station has low SVF whereas Cheongsong and Chupungryong station have high SVF. In order to validation the contribution of topographic effect, the solar radiation calculated using GWNU solar radiation model according to the sky line and SVF under the same meteorological conditions. As a result, direct, diffuse and global solar radiation were decreased by 12.0, 5.6, and 4.7% compared to plane surface on Cheongsong station. The 6 stations were decreased amount of mean daily solar radiation to the annual solar radiation. Among 42 stations, eight stations were analyzed as the urgent transfer stations or moving equipment quickly and more than half of stations (24) were required to review the observational environment. Since the DEM data do not include artifacts and vegetation around the station, the stations need a detail survey of observational environment.

Effect of micro-environment in ridge and southern slope on soil respiration in Quercus mongolica forest

  • Lee, Jae-Seok
    • Journal of Ecology and Environment
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    • v.42 no.4
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    • pp.210-218
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    • 2018
  • Background: Soil respiration (Rs) is a major factor of the absorption and accumulation of carbon through photosynthesis in the ecosystem carbon cycle. This directly affects the amount of net ecosystem productivity, which affects the stability and sustainability of the ecosystem. Understanding the characteristics of Rs is indispensable to scientifically understand the carbon cycle of ecosystems. It is very important to study Rs characteristics through analysis of environmental factors closely related to Rs. Rs is affected by various environmental factors, such as temperature, precipitation, soil moisture, litter supply, organic matter content, dominant plant species, and soil disturbance. This study was conducted to analyze the effects of micro-topographical differences on Rs in forest vegetation by measuring the Rs on the ridge and southern slope sites of the broadly established Quercus mongolica forest in the central Korean area. Method: Rs, Ts, and soil moisture data were collected at the southern slope and ridge of the Q. mongolica forest in the Mt. Jeombong area in order to investigate the effects of topographical differences on Rs. Rs was collected by the closed chamber method, and data collection was performed from May 2011 to October 2013, except Winter seasons from November to April or May. For collecting the raw data of Rs in the field, acrylic collars were placed at the ridge and southern slope of the forest. The accumulated surface litter and the soil organic matter content (SOMC) were measured to a 5 cm depth. Based on these data, the Rs characteristics of the slope and ridge were analyzed. Results: Rs showed a distinct seasonal variation pattern in both the ridge and southern slope sites. In addition, Rs showed a distinct seasonal variation with high and low Ts changes. The average Rs measurements for the two sites, except for the Winter periods that were not measured, were $550.1\;mg\;CO_2m^{-2}h^{-1}$ at the ridge site and $289.4\;mg\;CO_2m^{-2}h^{-1}$ at the southern slope, a difference of 52.6%. There was no significant difference in the Rs difference between slopes except for the first half of 2013, and both sites showed a tendency to increase exponentially as Ts increased. In addition, although the correlation is low, the difference in Rs between sites tended to increase as Ts increased. SMC showed a large fluctuation at the southern slope site relative to the ridge site, as while it was very low in 2013, it was high in 2011 and 2012. The accumulated litter of the soil surface and the SOMC at the depth range of 0~5 cm were $874g\;m^{-2}$ and 23.3% at the ridge site, and $396g\;m^{-2}$ and 19.9% at the southern slope site. Conclusions: In this study, Rs was measured for the ridge and southern slope sites, which have two different results where the surface litter layer is disturbed by strong winds. The southern slope site shows that the litter layer formed in autumn due to strong winds almost disappeared, and while in the ridge site, it became thick due to the transfer of litter from the southern slope site. The mean Rs was about two times higher in the ridge site compared to that in the southern slope site. The Rs difference seems to be due to the difference in the amount of litter accumulated on the soil surface. As a result, the litter layer supplied to the soil surface is disturbed due to the micro-topographical difference, as the slope and the change of the community structure due to the plant season cause heterogeneity of the litter layer development, which in turn affects SMC and Rs. Therefore, it is necessary to introduce and understand these micro-topographical features and mechanisms when quantifying and analyzing the Rs of an ecosystem.