• Title/Summary/Keyword: Flooded area

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A Case Study on the Estimation of Flooded Area using GIS (GIS를 이용한 홍수피해지역 분석에 관한 사례연구)

  • Ahn, Sang-Jin;Jun, Kye-Won;Kim, Jin-Guek
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.305-308
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    • 2002
  • This study is that analyzes the flood damages caused by rainfall during typhoon and how inundated area should be affected. Using HEC-HMS for analyzing rainfall-runoff and GIS (Geography Information System) for analyzing inundated area and volume. Each model was applied to Seopyung area for runoff effect analysis. As the result, Damaged area was magnified gradually according to the increase of rainfall and GIS was good for calculating the exact flood damage area at varied time.

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Estimation of the Flood Area Using Multi-temporal RADARSAT SAR Imagery

  • Sohn, Hong-Gyoo;Song, Yeong-Sun;Yoo, Hwan-Hee;Jung, Won-Jo
    • Korean Journal of Geomatics
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    • v.2 no.1
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    • pp.37-46
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    • 2002
  • Accurate classification of water area is an preliminary step to accurately analyze the flooded area and damages caused by flood. This step is especially useful for monitoring the region where annually repeating flood is a problem. The accurate estimation of flooded area can ultimately be utilized as a primary source of information for the policy decision. Although SAR (Synthetic Aperture Radar) imagery with its own energy source is sensitive to the water area, its shadow effect similar to the reflectance signature of the water area should be carefully checked before accurate classification. Especially when we want to identify small flood area with mountainous environment, the step for removing shadow effect turns out to be essential in order to accurately classify the water area from the SAR imagery. In this paper, the flood area was classified and monitored using multi-temporal RADARSAT SAR images of Ok-Chun and Bo-Eun located in Chung-Book Province taken in 12th (during the flood) and 19th (after the flood) of August, 1998. We applied several steps of geometric and radiometric calculations to the SAR imagery. First we reduced the speckle noise of two SAR images and then calculated the radar backscattering coefficient $(\sigma^0)$. After that we performed the ortho-rectification via satellite orbit modeling developed in this study using the ephemeris information of the satellite images and ground control points. We also corrected radiometric distortion caused by the terrain relief. Finally, the water area was identified from two images and the flood area is calculated accordingly. The identified flood area is analyzed by overlapping with the existing land use map.

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Inundating Disaster Assessment in Coastal Areas Using Urban Flood Model (도시홍수모델을 이용한 해안지역의 침수재해평가)

  • Yoo Hwan-Hee;Kim Weon-Seok;Kim Seong-Sam
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.3
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    • pp.299-309
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    • 2006
  • In recent years, a large natural disasters have occurred due to worldwide abnormal weather and the amount of damage has been increased more resulting from high density population and a large-sized buildings of the urbanized area. In this study. we estimate the flooded area according to rainfall probability intensify and sea level in Woreong dong, Masan occurred flood damages by typhoon Maemi using SWMM, a dynamic rainfall-runoff simulation model in urban area, and then analyze the damage of flood expected area through connecting with GIS database. In result, we can predict accurately expected area of inundation according to the rainfall intensity and sea level rise through dividing the study area into sub-area and estimating a flooded area and height using SWMM. We provide also the shelter information available for urban planning and flood risk estimation by landuse in expected flood area. Further research for hazard management system construction linked with web or wireless communication technology expects to increase its application.

Development of DNA-Based Assessment Method for Mold in Floor Dust of Dwellings in Korea (바닥 먼지내에서 DNA 기반 곰팡이 분석기법 개발)

  • Lee, Jeong-Sub;Kim, Sung Yeon;Choi, Kil Yong;Ryu, Jungmin;Hwang, Eun Seol;Lee, Juyeong;Kwon, Myunghee;Chung, Hyenmi;Seo, SungChul
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.27 no.4
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    • pp.324-332
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    • 2017
  • Objectives: Much scientific evidence indicate a positive association between moldy environments and respiratory illnesses and/or symptoms. However, few comprehensive assessments of mold have been performed for such settings. Spore counts or microscopic enumeration only may not be sufficient for evaluating fungal exposure. Recently, Mold Specific QPCR technology developed by the US EPA (Environmental Relative Moldiness Index, ERMI) has been widely used worldwide and great performance for assessing fungal exposure has been shown. Methods: We aimed to develop a Korean version of ERMI suitable for the distribution of fungal flora in Korea. Thirty dwellings in the Seoul and Incheon area were selected for sampling, and each was classified as 'Flooded, 'Water-damaged' or 'Non-water-damaged'. Results: Dust on the floor and airborne sampling were collected using an MAS100 and a 'Dustream' collector. Samples were analyzed by quantitative polymerase chain reaction(QPCR) for the 36 molds belonging to ERMI. Student t-test and ANOVA tests were carried out using SAS software. The median ERMI values of flooded, water damaged, and non-water damaged dwellings were 8.24(range: -5.6 to 27.9), 5.47(-25. 4 to 32.7), and -15.30(-24.6 to 14.8), respectively. Significant differences were observed between flooded and non-water damaged dwellings (P=0.001) and between water-damaged and non-water damaged dwellings (P=0.032). Conclusion: Our findings indicate that ERMI values attributed to dust samples in Korea could be applicable for the identification of flooded or water damaged buildings. However, much data is needed for continuously developing the Korean version of ERMI values.

Comparison of SAR Backscatter Coefficient and Water Indices for Flooding Detection

  • Kim, Yunjee;Lee, Moung-Jin
    • Korean Journal of Remote Sensing
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    • v.36 no.4
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    • pp.627-635
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    • 2020
  • With the increasing severity of climate change, intense torrential rains are occurring more frequently globally. Flooding due to torrential rain not only causes substantial damage directly, but also via secondary events such as landslides. Therefore, accurate and prompt flood detection is required. Because it is difficult to directly access flooded areas, previous studies have largely used satellite images. Traditionally, water indices such asthe normalized difference water index (NDWI) and modified normalized difference water index (MNDWI) which are based on different optical bands acquired by satellites, are used to detect floods. In addition, as flooding likelihood is greatly influenced by the weather, synthetic aperture radar (SAR) images have also been used, because these are less influenced by weather conditions. In this study, we compared flood areas calculated from SAR images and water indices derived from Landsat-8 images, where the images were acquired at similar times. The flooded area was calculated from Landsat-8 and Sentinel-1 images taken between the end of May and August 2019 at Lijiazhou Island, China, which is located in the Changjiang (Yangtze) River basin and experiences annual floods. As a result, the flooded area calculated using the MNDWI was approximately 21% larger on average than that calculated using the NDWI. In a comparison of flood areas calculated using water indices and SAR intensity images, the flood areas calculated using SAR images tended to be smaller, regardless of the order in which the images were acquired. Because the images were acquired by the two satellites on different dates, we could not directly compare the accuracy of the water-index and SAR data. Nevertheless, this study demonstrates that floods can be detected using both optical and SAR satellite data.

A Study on the Living Environment Organization System in Traditional Village - In the case of the Sugok-dong in the Imha Dam Flooded Area - (전통마을 생활환경 구성체계와 주생활 특성에 관한 연구 - 임하댐 수몰지역의 수곡동을 대상으로 -)

  • 정준현
    • Journal of the Korean housing association
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    • v.1 no.1
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    • pp.65-76
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    • 1990
  • Sugok Villiage. of the prospective flooded villiages for building Im Ha Dam, is selected as the studied place. Primarily, the purpose of this study is invested, recerded about traditional living environment, and then searched to find out possibilites on the context of the inheritance of analyzing about life contents and space. The result of this study are as follows:1) In composition of living environment, thinking view on confucianism and living view on folk beliefs are considered as important element2) Hierarchy of life environment is appeared of above and below space.(focused on JONG KA) and inner and outer space(boarded on pine forest) on the other hand according to living territory life environment can be divided into five territories.3) Confucian ideas, social status, folk beliefs and economics has been affected about formation of individual life. Accordingly, I believe that true inheritance of traditional culture was, through preserving mental contents as well as physical contents, possible.

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Study on the Refuge Behavior in Flooded Area and its Simulation Based on the Questionnaire Survey (앙케이트 조사에 기초한 침수지역 주민의 피난항동과 피난 모의실험에 관한 연구)

  • Kim, Sang-Hyeok
    • Journal of Korea Water Resources Association
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    • v.37 no.3
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    • pp.241-248
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    • 2004
  • In order to reduce flood damage, it is necessary to build up comprehensive flood control, including structural and non-structural countermeasures. In this paper, the decision making factors of individual refuge activities which are major non-structural activities to save peoples, lives against flood have been estimated based on questionnaire survey. Furthermore, in order to effective flood countermeasures, the refuge place and its distance are analyzed by questionnaire survey in the flooded area caused by typhoon RUSA and MEAMI. The refuge running time was assessed by its simulation. As a result of the simulation, it was found that the refuge running time is effected by refuge distance and the family numbers for refuge.