• Title/Summary/Keyword: Flood risk map

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Flood Risk Mapping with FLUMEN model Application (FLUMEN 모형을 적용한 홍수위험지도의 작성)

  • Cho, Wan Hee;Han, Kun Yeun;Ahn, Ki Hong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.2B
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    • pp.169-177
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    • 2010
  • Recently due to the typhoon and extreme rainfall induced by abnormal weather and climate change, the probability of severe damage to human life and property is rapidly increasing. Thus it is necessary to create adequate and reliable flood risk map in preparation for those natural disasters. The study area is Seo-gu in Daegu which is located near Geumho river, one of the tributaries of Nakdong river. Inundation depth and velocity at each time were calculated by applying FLUMEN model to the target area of interest, Seo-gu in Daegu. And the research of creating flood risk map was conducted according to the Downstream Hazard Classification Guidelines of USBR. The 2-dimensional inundation analysis for channels and protected lowland with FLUMEN model was carried out with the basic assumption that there's no levee failure against 100 year precipatation and inflow comes only through the overflowing to the protected lowland. The occurrence of overflowing was identified at the levee of Bisan-dong located in Geumho watershed. The level of risk was displayed for house/building residents, drivers and pedestrians using information about depth and velocity of each node computed from the inundation analysis. Once inundation depth map and flood risk map for each region is created with this research method, emergency action guidelines for residents can be systemized and it would be very useful in establishing specified emergency evacuation plans in case of levee failure and overflowing resulting from a flood.

Development of a Prototype for GIS-based Flood Risk Map Management System (GIS를 이용한 홍수위험지도 관리시스템 프로토타입 개발에 관한 연구)

  • Kim, Kye-Hyun;Yoon, Chun-Joo;Lee, Sang-Il
    • Journal of Korea Water Resources Association
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    • v.35 no.4 s.129
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    • pp.359-366
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    • 2002
  • The damages from the natural disasters, especially from the floods, have been increasing. Therefore, it is imperative to establish a BMP to diminish the damages from the floods and to enhance the welfare of the nation. Developed countries have been generating and utilizing flood risk maps to raise the alertness of the residents, and thereby achieving efficient flood management. The major objectives of this research were to develop a prototype management system for flood risk map to forecast the boundaries oi the inundation and to plot them through the integration of geographic and hydrologic database. For more efficient system development, the user requirement analysis was made. The GIS database design was done based on the results from the research work of river information standardization. A GIS database for the study area was built by using topographic information to support the hydrologic modeling. The developed prototype include several modules; river information edition module, map plotting module, and hydrologic modeling support module. Each module enabled the user to edit graphic and attribute data, to analyze and to represent the modeling results visually. Subjects such as utilization of the system and suggestions for future development were discussed.

Flood risk estimation with scenario-based, coupled river-overland hydrodynamic modeling (시나리오 기반 하천-제내지 연계 통합수리해석에 의한 홍수위험도 산정)

  • Lee, Jae Young;Nam, Myeong Jun;Kwon, Hyun Han;Kim, Ki Young
    • Journal of Korea Water Resources Association
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    • v.49 no.9
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    • pp.773-787
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    • 2016
  • A coupled river-overland hydrodynamic model was applied to estimate flood risk by a scenario-based approach. The study area is Seongseo Industrial Complex in Daegu which is located near Nakdong river and Geumho river. Inundation depth and velocity at each time were calculated by applying a coupled 1D/2D hydrodynamic model to the target area of interest. The 2D inundation analysis for river and overland domain was performed with the scenario-based approach that there are levee overflow against 100/200 year high quantile (97.5%) design flood and levee break against 100/200 year normal quantile (50%) design flood. The level of flood risk was displayed for resident/industrial area using information about maximum depth and velocity of each node computed from the 2D inundation map. The research outcome would be very useful in establishing specified emergency action plans (EAP) in case of levee break and overflowing resulting from a flood.

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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Evaluation of an Applicability of HEC-RAS 5.0 for 2-D Flood Inundation Analysis (2차원 홍수범람해석을 위한 HEC-RAS 5.0 적용성 평가)

  • Lee, Choon-Ho;Lee, Tae-Geun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.726-733
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    • 2016
  • Recently, the flood frequency and magnitude have increased due to heavy rainfall. Considering the present condition, a flood risk map has been published in many countries to raise awareness about flood damage to people. A flood inundation analysis model, which is used to publish the flood risk map, can be classified as river and inland inundation models according to the inundation cause. Although a variety of flood inundation analysis models are utilized both domestically and overseas, their usability is limited by the expensive price, except for the HEC-RAS model developed by U.S. Army Corps of Engineers (USACE). In the situation, the USACE has developed a 2-D HEC-RAS model that can be linked to the existing 1-D model. This model has been released as a beta version under the name, HEC-RAS 5.0. In this study, the HEC-RAS 5.0 model's features, usability, applicability, and accuracy were evaluated by comparing the performances on Gokgyo-cheon with the FLUMEN model, which is used for domestic flood risk mapping. The results of this study will contribute to river inundation analysis in many different ways after the HEC-RAS 5.0 model is stabilized.

Vulnerability Analysis in the Nakdong River Basin for the Utilization of Flood Risk Mapping (홍수위험지도 활용을 위한 낙동강 유역에서의 홍수취약도 분석)

  • Kim, Tae-Hyung;Han, Kun-Yeun;Cho, Wan-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.3
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    • pp.203-222
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    • 2011
  • The characteristics of flood damages have been increasingly strengthened and take the form of unpredictable and unusual weather phenomena caused by climate change and climate anomalies. To prevent inundation damage caused by breach of hydraulic structure such as dam or levee, and trouble of drainage of inner basin, the prediction necessity of flood inundation area, flood risk analysis, and drawing flood risk maps have been on the rise, and the national flood risk maps have been produced. In this study, the quantitative flood vulnerability analysis was performed, which represents population living within flood-affected areas, types of economic activities, facilities affected by flood, in order to extend flood risk mapping from simple hazard concept into risk based idea. By applying it to Nakdong River basin, the flood vulnerability indices were estimated to draw flood risk maps subdivided into administrative districts. The result of this study can be applied to establish the disaster prevention measures and priority decision of disaster prevention project.

2-D Inundation Analysis According to Post-Spacing Density of DEMs from LiDAR Using GIS (GIS를 활용한 LiDAR 자료의 밀도에 따른 2차원 침수해석)

  • Ha, Chang-Yong;Han, Kun-Yeun;Cho, Wan-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.1
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    • pp.74-88
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    • 2010
  • In this study, the points of LiDAR were modified in order to generate various DEM resolutions by applying LiDAR data in Ulsan. Since the LiDAR data have points with 1m intervals, the number of points for each resolution was modified to the size of 1, 5, 10, 30, 50, 100m by uniformly eliminating the points. A runoff analysis was performed on Taehwa river and its tributary, Dongcheon, with 200 year rainfall exceedance probability. 2-dimensional inundation analysis was performed based on the density of LiDAR data using FLUMEN, which was used to establish domestic flood risk map. Once DEM data obtained from LiDAR survey are used, it is expected that the study results can be used as data in determining optimal grid spacing, which is economical, effective and accurate in establishing flood defence plans including the creation of flood risk map.