• Title/Summary/Keyword: localized torrential downpour

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An Estimation to Landslide Vulnerable Area of Rainfall Condition using GIS (GIS를 이용한 강우조건에 따른 산사태 취약지 평가)

  • Yang, In-Tae;Chun, Ki-Sun;Park, Jae-Kook;Lee, Sang-Yeun
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.1 s.39
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    • pp.39-46
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    • 2007
  • Most areas in Kangwon Province are mountainous and vulnerable to landslide due to the rainy season in summer and the localized torrential downpour triggered by abnormal climate. In particular, the rainfall is one of direct reasons for landslide. In accordance with the analysis of the relevance between the landslide areas and the accumulated rainfall for four months, there are severe damages of landslide to the areas having more than 1,100 mm of rainfall during three(3) months. Further, it indicates that the more the accumulated rainfall is the greater the size of landslide. These analyses show that the rainfall causes the possible and potential landslide in the vulnerable areas. And also, it means that there exist strong possibilities of landslide even in the areas of lower vulnerability if the amount of rainfall is above certain standard level. Accordingly, in this study we stored the GIS database on the causes and factors of landslide in the southern parts of Kangwon province and conducted simulations on the change of distribution of vulnerable areas by varying the rainfall conditions and by using the evaluation data of landslide vulnerability. As such a result, we found that the landslide could potentially occur if the amount of rainfall is 200 mm and more.

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Annual Distribution of Heterotrophic Bacterial Community in the Marine Ranching Ground of Tongyeong Coastal Waters (통영 바다목장 해역의 종속영양세균 군집의 연차적 분포)

  • Kim, Mal-Nam;Lee, Han-Woong;Lee, Jin-Hwan
    • Korean Journal of Environmental Biology
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    • v.25 no.3
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    • pp.273-278
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    • 2007
  • The cell numbers of heterotrophic bacteria inhabiting the surface and bottom sea water harvested from the 5 stations in the marine ranching ground of Tongyeong coastal waters in $2003{\sim}2007$ were examined, and species composition of the heterotrophic bacterial population and dominant species were analyzed as well. Sea water samples collected in summer season contained much higher number of heterotrophic bacteria than those harvested in winter, spring and autumn seasons due to the higher sea water temperature. However the cell number of heterotrophic bacteria did not show a significant dependence on the location of the sampling stations. The cell number of heterotrophic bacteria in the surface sea water harvested in October 2003 and in September 2004 was not discernibly different from that in the bottom sea water and sometimes the former was even fewer than the latter because of the typhoon and localized torrential downpour. The number of heterotrophic bacteria decreased every year. The main bacterial species were Pseudomonas fluorescens TY1, Pseudomonas stutzeri TY2, Acinetobacter lwoffii TY3, Sphingomonas paucimobilis TY4, Burkholderia mallei TY5, Pasteurella haemolytica TY6, Pasteurella multocida TY7, Comamonas acidovorans TY8, Actinobacillus ureae TY9 and Chryseobacterium indologenes TY10. P. fluorescens TY1 and A. lwoffii TY3 were found to be the dominant species.

Geosynthetic Reinforced Soil Method for Restoration of Debris Flow Failure Slopes (쇄설성 유동파괴 사면 복구를 위한 토목섬유 보강토 공법)

  • Cho Yong-Seong;Kim You-Seong;Park Inn-Joon
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.93-101
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    • 2005
  • The formation of slopes is unavoidable under the special circumstance of Korea where $7%$ of the whole area are composed of mountains and civil engineering projects such as road and site developments are increasing with industrial development and horizontal expansions of urban area. Stability of slopes is one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall is concentrated in summer season and the localized torrential downpour is getting more frequent recently. As a result of these circumstances, partial slope failures by debris flow of the high water content soils occur frequently in cut soil slopes. In this case of debris flow slope failure, slope declination method is selected fur the stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. For debris flow failure slopes, this study secured the safety of slopes by preventing the inflow of rainwater and scour using geosynthetics-reinforced embankment, and created nature-friendly slopes by planting trees on the slopes.