• Title/Summary/Keyword: Flood disaster

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Decision-Making Model Research for the Calculation of the National Disaster Management System's Standard Disaster Prevention Workforce Quota : Based on Local Authorities

  • Lee, Sung-Su;Lee, Young-Jai
    • Journal of Information Technology Applications and Management
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    • v.17 no.3
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    • pp.163-189
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    • 2010
  • The purpose of this research is to develop a decision-making model for the calculation of the National Disaster Management System's standard prevention workforce quota. The final purpose of such model is to support in arranging a rationally sized prevention workforce for local authorities by providing information about its calculation in order to support an effective and efficient disaster management administration. In other words, it is to establish and develop a model that calculates the standard disaster prevention workforce quota for basic local governments in order to arrange realistically required prevention workforce. In calculating Korea's prevention workforce, it was found that the prevention investment expenses, number of prevention facilities, frequency of flood damage, number of disaster victims, prevention density, and national disaster recovery costs have positive influence on the dependent variable when the standard prevention workforce was set as the dependent variable. The model based on the regression analysis-which consists of dependent and independent variables-was classified into inland mountainous region, East coast region, Southwest coastal plain region to reflect regional characteristics for the calculation of the prevention workforce. We anticipate that the decision-making model for the standard prevention workforce quota will aid in arranging an objective and essential prevention workforce for Korea's basic local authorities.

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Comparative study of flood detection methodologies using Sentinel-1 satellite imagery (Sentinel-1 위성 영상을 활용한 침수 탐지 기법 방법론 비교 연구)

  • Lee, Sungwoo;Kim, Wanyub;Lee, Seulchan;Jeong, Hagyu;Park, Jongsoo;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.57 no.3
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    • pp.181-193
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    • 2024
  • The increasing atmospheric imbalance caused by climate change leads to an elevation in precipitation, resulting in a heightened frequency of flooding. Consequently, there is a growing need for technology to detect and monitor these occurrences, especially as the frequency of flooding events rises. To minimize flood damage, continuous monitoring is essential, and flood areas can be detected by the Synthetic Aperture Radar (SAR) imagery, which is not affected by climate conditions. The observed data undergoes a preprocessing step, utilizing a median filter to reduce noise. Classification techniques were employed to classify water bodies and non-water bodies, with the aim of evaluating the effectiveness of each method in flood detection. In this study, the Otsu method and Support Vector Machine (SVM) technique were utilized for the classification of water bodies and non-water bodies. The overall performance of the models was assessed using a Confusion Matrix. The suitability of flood detection was evaluated by comparing the Otsu method, an optimal threshold-based classifier, with SVM, a machine learning technique that minimizes misclassifications through training. The Otsu method demonstrated suitability in delineating boundaries between water and non-water bodies but exhibited a higher rate of misclassifications due to the influence of mixed substances. Conversely, the use of SVM resulted in a lower false positive rate and proved less sensitive to mixed substances. Consequently, SVM exhibited higher accuracy under conditions excluding flooding. While the Otsu method showed slightly higher accuracy in flood conditions compared to SVM, the difference in accuracy was less than 5% (Otsu: 0.93, SVM: 0.90). However, in pre-flooding and post-flooding conditions, the accuracy difference was more than 15%, indicating that SVM is more suitable for water body and flood detection (Otsu: 0.77, SVM: 0.92). Based on the findings of this study, it is anticipated that more accurate detection of water bodies and floods could contribute to minimizing flood-related damages and losses.

Development of Strategics for Establishment of Spatial Information by Assessment of GIS-Based Flood Risk (GIS기반 홍수위험도 평가를 통한 공간정보 구축 방안 개발)

  • Sim, Gyoo Seong;Lee, Choon Ho;Lee, Tae Geun;Jee, Gye Hwan
    • Spatial Information Research
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    • v.23 no.2
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    • pp.39-48
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    • 2015
  • In this study, we evaluated flood risk by applying calculation fomula considering practical risk calculated by inundation analysis information through 2D inundation analysis, suggested a plan that provides a standardized information system. Generally, we evaluated flood risk to people and classified four degrees by using inundation depth, velocity, Debris Factor and Flood Hazard Rating relationship because current flood risk assessment method based inundation depth and area was considered to not fully reflect the actual risk to people on flood. We simulated overflow and levee break scenarios according to 500 year and 200 year floods, respectively, by using Flumen which is a 2D flood inundation model for Geumho river basin in Daegu. The result of this study could contribute to inform practical risk information to people in expected flood area. This study can be useful for the fields of disaster estimatingsuch as information analysis, evaluation, planning by offering Risk information based on standardized information system.

A study on development of flood depth-damage functions focused on school buildings (학교건물에 대한 홍수 침수심별 손상함수 개발에 관한 연구)

  • Lee, Chang Hee;Kim, Sang Ho;Hwang, Shin Bum;Kim, Gil Ho
    • Journal of Korea Water Resources Association
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    • v.50 no.8
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    • pp.513-520
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    • 2017
  • In order to analyze flood damage mitigation effects, it is necessary not only to analyze inundation areas and depth through hydraulic and hydrological analysis but also to estimate flood damages. Flood damages of structure and contents of buildings are generally analyzed according to the flood depth. In this study, we developed and applied flood depth-damage functions for the school buildings based on actual damage data. In addition, the development and modification procedure of flood depth-damage functions for school buildings is presented in this paper, and the developed damage functions are verified by comparing them with the existing method. It is expected that the process of developing and applying flood depth-damage functions presented in this study can be used in the cost benefit analysis of flood damage mitigation measures.

Development of Urban Flood Analysis Model Adopting the Unstructured Computational Grid (비정형격자기반 도시침수해석모형 개발)

  • Lee, Chang Hee;Han, Kun Yeun;Kim, Ji Sung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5B
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    • pp.511-517
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    • 2006
  • Flood damage is one of the most important and influential natural disaster which has an effect on human beings. Local concentrated heavy rainfall in urban area yields flood damage increase due to insufficient capacity of drainage system. When the excessive flood occurs in urban area, it yields huge property losses of public facilities involving roadway inundation to paralyze industrial and transportation system of the city. To prevent such flood damages in urban area, it is necessary to develop adequate inundation analysis model which can consider complicated geometry of urban area and artificial drainage system simultaneously. In this study, an urban flood analysis model adopting the unstructured computational grid was developed to simulate the urban flood characteristics such as inundation area, depth and integrated with subsurface drainage network systems. By the result, we can make use of these presented method to find a flood hazard area and to make a flodd evacuation map. The model can also establish flood-mitigation measures as a part of the decision support system for flood control authority.

Development of 3D GIS System for the Visualization of Flood Inundation Area (홍수범람지역 가시화를 위한 3차원 GIS 시스템 개발)

  • Lee, Geun Sang;Jeong, Il Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5D
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    • pp.749-757
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    • 2008
  • Recently, flood damages have increased with heavy rainfall and typhoon influences, and it requires that visualization information to the flood inundation area of downstream in dam discharge. This study developed 3D GIS system that can visualize flood inundation area for Namgang Dam downstream. First, DEMs extracted from NGIS digital maps and IKONOS satellite images were optimized to mount in iWorld engine using TextureMaker and HeightMaker modules. And flood inundation area of downstream could be efficiently extracted with real-time flooding water level using Coordinate Operation System for Flood control In Multi-reservoir (COSFIM) and Flood Wave routing model (FLDWAV) in river cross section. This visualization information of flood inundation area can be used to examine flood weakness district needed in real time Dam operation and be applied to establish the rapid flood disaster countermeasures efficiently.

Analysis of the Impact of Building Congested Area for Urban Flood Analysis (도심지 침수해석을 위한 건축물 밀집 지역 영향 분석)

  • Kim, Sung-Uk;Jun, Kye-Won;Lee, Seung-Hee;Pi, Wan-Seop
    • Journal of Korean Society of Disaster and Security
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    • v.15 no.3
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    • pp.41-46
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    • 2022
  • Recently, the scale of flood damage occurring in urban areas is increasing due to climate change and urbanization, so various flooding analysis techniques are needed. In the Sadangcheon Stream basin, which has been continuously flooded since 2010, a basic plan for improving drainage was established using XP-SWMM and measures to prevent flooding were proposed. However, in the process of inundation analysis, the analysis considering the city's buildings was not conducted, resulting in a problem that the degree of flooding damage tends to be overestimated. Therefore, in this study, XP-SWMM was used to compare and analyze cases where buildings were not considered and designated as inactive areas. As a result of the study, it was analyzed if the building was not considered, the flood damaged area was 271,100 m2 and the depth of submersion was 0.15 m, and if the building was considered inactive area, the flood damaged area was 172,900 m2 and the depth of submersion was 0.32 m that it is under-estimated about 36% and an flow velocity around the building increased from 1.62 m/s to 1.83 m/s about 1.12 times.

A Study on Water Surface Detection Algorithm using Sentinel-1 Satellite Imagery (Sentinel-1 위성영상을 이용한 수표면 면적 추정 알고리즘에 관한 연구)

  • Lee, Dalgeun;Cheon, Eun Ji;Yun, Hyewon;Lee, Mi Hee
    • Korean Journal of Remote Sensing
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    • v.35 no.5_2
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    • pp.809-818
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    • 2019
  • The Republic of Korea is very vulnerable to damage from storm and flood due to the rainfall phenomenon in summer and the topography of the narrow peninsula. The damage is recently getting worse because of the concentration rainfall. The accurate damage information production and analysis is required to prepare for future disaster. In this study, we analyzed the water surface area changes of Byeokjeong, Sajeom, Subu and Boryeong using Sentinel-1 satellite imagery. The surface area of the Sentinel-1 satellite, taken from May 2015 to August 2019, was preprocessed using RTC and image binarization using Otsu. The water surface area of reservoir was compared with the storage capacity from WAMIS and RIMS. As a result, Subu and Boryeong showed strong correlations of 0.850 and 0.941, respectively, and Byeokjeong and Sajeom showed the normal correlation of 0.651 and 0.657. Thus, SAR satellite imagery can be used to objective data as disaster management.

Development and application of the estimation method of flood damage in the ungauged basin using satellite data (위성자료를 활용한 미계측유역의 홍수피해액 추산기법 개발 및 적용)

  • Yeom, Woong-Sun;Park, Dong-Hyeok;Ahn, Jaehyun
    • Journal of Korea Water Resources Association
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    • v.53 no.12
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    • pp.1183-1192
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    • 2020
  • Economic analysis is a basic step in establishing disaster mitigation measures, but it is difficult to verify the results due to uncertainty. Therefore, the scope of investigation and analysis is wide. However, it is difficult to predict the amount of damage caused by flooding because the collection of relevant data is limited in the ungauged basin. In this study, distributed runoff analysis and flooding analysis were performed, and a method of estimating the amount of flood damage in the ungauged basin was proposed using collectible social and economic indicators and flood analysis results. For distributed runoff analysis and flooding analysis, GRM (Grid based Rainfall-runoff Model) and G2D (Grid based 2-Dimensional land surface flood model) developed by Korea Institute of Civil engineering and Building Technology were used. The method of substituting collectible social and economic indicators into the simple method and improvement method was used to estimate the amount of flood damage. As a result of the study, it was possible to estimate the amount of flood damage using satellite data and social and economic indicators in the ungauged basin.

A Study on the Inhabitant-friendly Improving a Village Environment in Rural Disaster Villages (농촌재난마을 주민친화형 마을환경개선 콘텐츠 적용방안에 관한 연구)

  • Kim, Eun-Ja;Park, Ro-Un;Lee, Seung-Chul;Lim, Chang-Su;Park, Mee-Jung;Jeon, Jeong-Bae
    • Journal of the Korean Institute of Rural Architecture
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    • v.20 no.4
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    • pp.53-64
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    • 2018
  • Disasters that occur most frequently in rural areas are drought, flood, damages from wind and cold weather. In order to overcome the damage caused by natural disasters, various projects related to safety and disaster prevention. However, Government-centered disaster recovery operating system showed difficulties to utilize the natural scenery and ecological environment of rural villages. So the participation of the residents is necessary. Therefore, this study aims to find a more effective disaster recovery direction by suggesting the application method, Inhabitant-friendly improving a village environment contents in Rural Disaster Villages, for continuous disaster management. The research methods were literature analysis, interviews, and expert discussion. As a result, it was found that the rural disaster village environmental improvement facilities, inhabitant-friendly recovery system, and inhabitant-friendly village environment contents and suggests a application method of inhabitant-friendly village environment contents. The research will be used as basic data when preparing a guide for improving the environment for residents in rural villages.