• Title/Summary/Keyword: Flood vulnerable area

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Application of Geographic Database for Prediction of Flood Vulnerable Area (홍수에 의한 침수 취약지역 예측에 관한 연구)

  • Hwang, Yoo-Jeong
    • Journal of the Korean association of regional geographers
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    • v.12 no.1
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    • pp.172-178
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    • 2006
  • There has been tremendous increase of disaster related damages since 1990's. Especially flood occurred in summer season highly populated area has led to demolish a lot of facilities and buildings within a short time period. This is to figure out the way to predict the vulnerable flood inundation area by past records of inundation and and geographic information available. The comparative study on 1998 and 1999 flood inundation area in Munsan and Gokneung river shows that 5 degree of slope and 10 m elevation level are dividing index to draw the vulnerable area. This study is to suggest the relatively easy method to predict flood vulnerable area and to apply the results to prepare for protecting the facilities and the people with other thematic geographic database.

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Application of the Fuzzy Method to Improve GIS Geomorphological Method of Predicting Flood Vulnerable Area

  • Kim Su Jeong;Yom Jae-Hong;Lee Dong-Cheon
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.264-267
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    • 2004
  • In identifying flood vulnerable areas, three methods are generally deployed: the geomorphology method which is based on topographic features; the past evidence method based on observed data of past actual floods; and, prediction of flood areas through hydrologic models. This study aims to improve the prediction model of the geomorphology method through the application of fuzzy method in GIS modeling. The generally used GIS method of superimposing thematic map layers assumes crisp boundaries of the layers, which results in either risk-averse solutions or risk-taking solutions. The introduction of fuzzy concepts to processing of evaluation criteria (DEM, slope, aspect) solves this problem. As the result of applying the fuzzy method to a test site in the west Nak-Dong river, similar flood vulnerable areas were predicted as when using the conventional Boolean criteria. The resulting map, however, showed varying degree of uncertainty of flooding in these areas. This extra information is deemed to be valuable in taking phased actions during flood response, leading to a more effective and timely decision-making.

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Climate Change Vulnerability Assessment in Rural Areas - Case study in Seocheon - (농촌지역 기후변화 취약성 평가에 관한 연구 - 서천군을 대상으로 -)

  • Lee, Gyeongjin;Cha, Jungwoo
    • Journal of Korean Society of Rural Planning
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    • v.20 no.4
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    • pp.145-155
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    • 2014
  • Since greenhouse gas emissions increase continuously, the authorities have needed climate change countermeasure for adapting the acceleration of climate change damages. According to "Framework Act on Low Carbon, Green Growth", Korean local governments should have established the implementation plan of climate change adaptation. These guidelines which is the implementation plan of climate change adaptation should be established countermeasure in 7 fields such as Health, Digester/Catastrophe, Agriculture, Forest, Ecosystem, Water Management and Marine/Fisheries. Basically the Korean local governments expose vulnerable financial condition, therefore the authorities might be assessed the vulnerability by local regions and fields, in order to establish an efficient implementation plan of climate change adaptation. Based on this concepts, this research used 3 methods which are LCCGIS, questionnaire survey analysis and analysis of existing data for the multiphasic vulnerable assessment. This study was verified the correlation among 7 elements of climate change vulnerability by 3 analysis methods, in order to respond climate change vulnerability in rural areas, Seocheon-gun. If the regions were evaluated as a vulnerable area by two or more evaluation methods in the results of 3 methods' comparison and evaluation, those areas were selected by vulnerable area. As a result, the vulnerable area of heavy rain and flood was Janghang-eup and Maseo-myeon, the vulnerable area of typhoon was Janghang-eup, Masan-myeon and Seo-myeon. 3 regions (i.e. Janghang-eup, Biin-myeon, Seo-myeon) were vulnerable to coastal flooding, moreover Masan-myeon, Pangyo-myeon and Biin-myeon exposed to vulnerability of landslide. In addition, Pangyo-myeon, Biin-myeon and Masan-myeon was evaluated vulnerable to forest fire, as well as the 3 sites; Masan-myeon, Masan-myeon and Pangyo-myeon was identified vulnerable to ecosystem. Lastly, 3 regions (i.e. Janghang-eup, Masan-myeon and Masan-myeon) showed vulnerable to flood control, additionally Janghang-eup and Seo-myeon was vulnerable to water supply. However, all region was evaluated vulnerable to water quality separately. In a nutshell this paper aims at deriving regions which expose climate change vulnerabilities by multiphasic vulnerable assessment of climate change, and comparing-evaluating the assessments.

Mapping Technique for Flood Vulnerable Area Using Surface Runoff Mechanism (지표유출메커니즘을 활용한 홍수취약지구 표출 기법)

  • LEE, Jae-Yeong;HAN, Kun-Yeun;KIM, Hyun-Il
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.4
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    • pp.181-196
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    • 2019
  • Floods can be caused by a variety of factors, and the main cause of floods is the exceeding of urban drainage system or river capacity. In addition, rainfall frequently occurs that causes large watershed runoff. Since the existing methodology of preparing for flood risk map is based on hydraulic and hydrological modeling, it is difficult to analyse for a large area because it takes a long time due to the extensive data collection and complex analysis process. In order to overcome this problem, this study proposes a methodology of mapping for flood vulnerable area that considered the surface runoff mechanism. This makes it possible to reduce the time and effort required to estimate flood vulnerabilities and enable detailed analysis of large areas. The target area is Seoul, and it was confirmed that flood damage is likely to occur near selected vulnerable areas by verifying using 2×2 confusion matrix and ROC curve. By selecting and prioritizing flood vulnerable areas through the surface runoff mechanism proposed in this study, the establishment of systematic disaster prevention measures and efficient budget allocation will be possible.

ROC Analysis of Topographic Factors in Flood Vulnerable Area considering Surface Runoff Characteristics (지표 유출 특성을 고려한 홍수취약지역 지형학적 인자의 ROC 분석)

  • Lee, Jae Yeong;Kim, Ji-Sung
    • Ecology and Resilient Infrastructure
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    • v.7 no.4
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    • pp.327-335
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    • 2020
  • The method of selecting an existing flood hazard area via a numerical model requires considerable time and effort. In this regard, this study proposes a method for selecting flood vulnerable areas through topographic analysis based on a surface runoff mechanism to reduce the time and effort required. Flood vulnerable areas based on runoff mechanisms refer to those areas that are advantageous in terms of the flow accumulation characteristics of rainfall-runoff water at the surface, and they generally include lowlands, mild slopes, and rivers. For the analysis, a digital topographic map of the target area (Seoul) was employed. In addition, in the topographic analysis, eight topographic factors were considered, namely, the elevation, slope, profile and plan curvature, topographic wetness index (TWI), stream power index, and the distances from rivers and manholes. Moreover, receiver operating characteristic analysis was conducted between the topographic factors and actual inundation trace data. The results revealed that four topographic factors, namely, elevation, slope, TWI, and distance from manholes, explained the flooded area well. Thus, when a flood vulnerable area is selected, the prioritization method for various factors as proposed in this study can simplify the topographical analytical factors that contribute to flooding.

Mapping of Inundation Vulnerability Using Geomorphic Characteristics of Flood-damaged Farmlands - A Case Study of Jinju City - (침수피해 정보를 이용한 농경지의 지형학적 침수취약지도 작성 - 진주시를 사례로 -)

  • Kim, Soo-Jin;Suh, Kyo;Kim, Sang-Min;Lee, Kyung-Do;Jang, Min-Won
    • Journal of Korean Society of Rural Planning
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    • v.19 no.3
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    • pp.51-59
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    • 2013
  • The objective of this study was to make a map of farmland vulnerability to flood inundation based on morphologic characteristics from the flood-damaged areas. Vulnerability mapping based on the records of flood damages has been conducted in four successive steps; data preparation and preprocessing, identification of morphologic criteria, calculation of inundation vulnerability index using a fuzzy membership function, and evaluation of inundation vulnerability. At the first step, three primary digital data at 30-m resolution were produced as follows: digital elevation model, hill slopes map, and distance from water body map. Secondly zonal statistics were conducted from such three raster data to identify geomorphic features in common. Thirdly inundation vulnerability index was defined as the value of 0 to 1 by applying a fuzzy linear membership function to the accumulation of raster data reclassified as 1 for cells satisfying each geomorphic condition. Lastly inundation vulnerability was suggested to be divided into five stages by 0.25 interval i.e. extremely vulnerable, highly vulnerable, normally vulnerable, less vulnerable, and resilient. For a case study of the Jinju, farmlands of $138.6km^2$, about 18% of the whole area of Jinju, were classified as vulnerable to inundation, and about $6.6km^2$ of farmlands with elevation of below 19 m at sea water level, slope of below 3.5 degrees, and within 115 m distance from water body were exposed to extremely vulnerable to inundation. Comparatively Geumsan-myeon and Sabong-myeon were revealed as the most vulnerable to farmland inundation in the Jinju.

A Study on Urban Flood Vulnerability Assessment Considering Social Impact (사회적 평가 지표를 반영한 도시 홍수취약성 평가)

  • Lee, Gyu Min;Choi, Jin Won;Jun, Kyung Soo
    • Land and Housing Review
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    • v.11 no.1
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    • pp.109-116
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    • 2020
  • This study aims to establish an approach to assess urban flood vulnerability by identifying social characteristics such as the road transportation and the vulnerable groups. Assessment procedures comprise three steps as: (1) composing the assessment criteria to reflect the urban characteristics; (2) calculating the weight; and (3) evaluating the vulnerability. The criteria were adopted by Delphi survey technique. Four criteria as land cover, residents, vulnerable areas, and disaster response were adopted in the current study. To determine the weight set of criteria, subjective and objective methods were combined. The weight set was determined using the combined method which reflects the Delphi method and Entropy analysis. In the process of data-based construction, GIS tools wwere used to extract administrative unit materials such as land cover, road status, and slope. Data on population and other social criteria were collected through the National Statistical Office and the Seoul Metropolitan statistical data. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) technique, which uses materials from cell units in order to rank the closest distance to the best case and the farthest distance from the worst case by calculating the distances to the area of assessment, was applied to assess. The study area was the Dorimcheon basin, a flood special treatment area of Seoul city. The results from the current study indicates that the established urban flood vulnerability assessment approach is able to predict the inherent vulnerable factors in urban regions and to propose the area of priority control.

Developing Coast Vulnerable Area Information Management System using Web GIS (Web GIS를 이용한 연안위험취약지역 정보시스템 구축)

  • Pak, Hyeon-Cheol;Kim, Hyoung-Sub;Jo, Myung-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.4
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    • pp.155-164
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    • 2005
  • The coast has been known as very vulnerable area. This area has nature disasters such as typhoon, tidal wave, flood and storm almost every year. In this study, coast vulnerable area information management system was developed to manage the coastal facilities and vulnerable area through Web GIS. This system is able to visualize the damage area and support the official work related to coast as efficient DSS(Decision Supporting System). Moreover, the foundation for domestic coast information management is expected by acquiring less cost and time. For this, GIS DB was first constructed by acquiring damage factor data such as typhoon, tidal wave, flood and storm. Then GIS analysis methods and high resolution satellite images are used to possibly present the results of retrieve as table, map, graph, inundation simulation in real time.

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Analysis of the Vulnerable Area about Inundation on the Upriver Basin of Dam by Flood Simulation Using GIS (GIS 홍수 시뮬레이션에 의한 댐 상류 유역의 침수 취약지역 분석)

  • Um, Dae-Yong;Kim, Ji-Hye
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.6
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    • pp.723-731
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    • 2009
  • Recently, it has been strangely increasing rainfall and rainfall meter by global warming. so flood damage is being increase. It has happened there are so many damaged by influence by backwater of dam. However, the alleviative solutions of flood damages are focused on the lower river basin where the density of population is higher than upper river basin. This research proceeds based on design and build 3D topography model and reflects the topographical factors of upper river basin. It also simulated the circumstances of flooding by investigation of factors of outflow, hence, as a result, we would find out the vulnerable area for flooding and scale of damages effectively. This research suggests the solution and method of flooding for vulnerable area of the flooding to reduce the damages by predicting flooding. Thus, the suggestion may support to make a decision efficiently to prevent the damage of flooding.

The Analysis of Flood Propagation Characteristics using Recursive Call Algorithm (재귀호출 알고리듬 기반의 홍수전파 특성 분석)

  • Lee, Geun Sang;Jang, Young Wun;Choi, Yun Woong
    • Spatial Information Research
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    • v.21 no.5
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    • pp.63-72
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    • 2013
  • This paper analyzed the flood propagation characteristics of each flood elevation due to failure of embankment in Muju Namdae Stream using recursive call algorithm. A flood propagation order by the flood elevation was estimated by setting destruction point at Beonggu and Chasan small dam through recursive call algorithm and then, the number of grids of each flood propagation order and accumulated inundation area were calculated. Based on the flood propagation order and the grid size of DEM, flood propagation time could be predicted each flood elevation. As a result, the study could identify the process of flood propagation through distribution characteristic of the flood propagation order obtained from recursive call algorithm, and could provide basic data for protection from flood disaster by selecting the flood vulnerable area through the gradient pattern of the graph for accumulated inundation area each flood propagation order. In addition, the prediction of the flood propagation time for each flood water level using this algorithm helped provide valuable information to calculate the evacuation path and time during the flood season by predicting the flood propagation time of each flood water level.