• Title/Summary/Keyword: Flood risk map

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Applicability of frequency based flood risk map for flood risk assessment (홍수위험도 평가를 위한 빈도별 홍수위험지도의 적용성에 관한 연구)

  • Yujin Kang;Won-joon Wang;Seongcheol Shin;Daegun Han;Soojun Kim;Hung Soo Kim
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.105-105
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    • 2023
  • 최근 기후변화로 인해 매년 집중호우 및 태풍으로 인한 침수피해가 증가하고 있다. 현재 국내에서는 이러한 피해를 줄이기 위해 구조적 대책뿐만 아니라 치수사업의 의사결정을 지원할 수 있는 비구조적 대책들이 대두되고 있다. 비구조적 대책으로는 재해예방사업 등에서 투자우선순위를 결정할 수 있는 다차원법, 홍수취약성지수 등과 같은 정량적, 정성적 홍수위험도 평가가 대표적이다. 하지만 기존 시군구별 홍수위험도 평가는 빈도별 홍수위험지도의 침수면적을 반영하지 않았었다. 따라서 본 연구에서는 서울특별시를 대상으로 빈도별(50, 80, 100 및 200년) 설계홍수량에 따른 홍수위험지도를 작성하고 IBA(Indicator Based Assessment) 방법을 활용한 홍수위험도 평가를 실시하였다. 홍수위험지수는 4가지 항목(Hazard, Exposure, Vulnerability 및 Capacity)과 8개의 세부지표로 구성하였다. 분석결과, 송파구와 성동구는 100년 빈도, 용산구와 강남구는 80년 빈도와 100년 빈도에서 홍수위험지수의 순위 변동이 관측되었다. 순위 변동이 발생한 주요 원인으로는 홍수위험도 평가에 반영된 Exposure 및 Vulnerability 항목에 포함된 세부지표별 지수가 시군구 내 빈도별 침수면적이 변화함에 따라 증가 혹은 감소했기 때문이었다. 본 연구를 활용하면 빈도별 침수면적 변화에 따른 시군구별 홍수위험도를 파악할 수 있으며, 그에 따른 예방책 또한 마련할 수 있을 것이다. 그리고 공간분석을 통해 도출된 통계지도를 활용하여 홍수위험에 직접적으로 노출된 건물 및 인구 밀집지역을 파악하고, 해당 지역을 대상으로 치수사업을 전개할 수 있을 것으로 판단된다.

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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.

Two-Dimensional Flood Inundation Analysis Resulting from Irrigation Reservoir Failure - Focused on the Real Case with the Minimal Data Set - (농업용 저수지 붕괴에 따른 2차원 홍수범람해석 -계측자료가 부족한 실제사례를 중심으로-)

  • Lee, Jae Young;Kim, Byunghyun;Park, Jun Hyung;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.2
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    • pp.231-243
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    • 2016
  • This study presents the applicability of two-dimensional (2D) flood inundation model by applying to real irrigation reservoir failure with limited available data. The study area is Sandae Reservoir placed in Gyeongju and downstream area of it and the reservoir was failured by piping in 2013. The breach hydrograph was estimated from one-dimensional (1D) hydrodynamic model and the discharge was employed for upstream boundary of 2D flood inundation model. Topography of study area was generated by integrating digital contour map and satellite data, and Cartesian grids with 3m resolution to consider geometry of building, road and public stadium were used for 2D flood inundation analysis. The model validation was carried out by comparing predictions with field survey data including reservoir breach outflow, flood extent, flood height and arrival time, and identifying rational ranges with allowed error. In addition, the applicability of 2D model is examined using different simulation conditions involving grid size, building and roughness coefficient. This study is expected to contributed to analysis of irrigation reservoirs were at risk of a failure and setting up Emergency Action Plan (EAP) against irrigation reservoir failure.

A Study on Estimation of Levee Safety Map for Determining the Priority of River Maintenance (하천 유지관리 우선순위 결정을 위한 제방안전도맵 산정방법 연구)

  • Yoon, Kwang Seok;Kim, Sooyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.17-25
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    • 2017
  • Owing to recent climate change, the scale of rainfall tends to increase gradually and the risk of flooding has increased. Therefore, the importance of improving the levee management and disaster response is increasing. Levee management in Korea is carried out at the level of damage recovery after the occurrence of damage. Therefore, it is necessary to develop a technology for predicting and managing the levee safety with proactive river management. In this study, a method to estimate the safety against erosion and overflow was suggested. A map of levee safety that can be used as basic data is presented by displaying the levee safety on the map. The levee erosion safety was calculated as the ratio of the internal and external force for each shore type. The levee overflow safety was calculated as the ratio of the maximum conveyance and design flood. The maximum conveyance was a discharge when the level of the river was equal to the level of the levee crown. The levee safety was classified into 5 grades: very safe, safe, normal, dangerous, and very dangerous. As a research area from downstream of Nam River Dam to Nakdong River Junction, the levee safety against erosion and overflow was estimated for all levees and all cross-sections of the river. The levee safety was displayed on a map using GIS. Through the levee safety map as a result of this study, the levee safety can be observed intuitively. Using the levee safety map, a maintenance plan for a river can be easy to build. This levee safety map can be used to help determine the priority of investment for efficient budget used.

A New Methodology for Flood Prediction Mapping Using Levee Risk Map (제방 리스크 지도를 활용한 새로운 침수예상도 작성)

  • Lee, Jae Yeong;Park, Jun Hyung;Han, Kun Yeun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.116-116
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    • 2016
  • 최근 이상기후로 인해 다양한 원인으로 홍수가 발생하고 있으며, 이에 대한 대책으로 가상의 강우 시나리오에 대한 침수예상도가 작성되어 해당지역의 주민들에게 정보를 제공하고 있다. 하지만 이러한 침수예상도가 나타내는 모든 지역에 대해 예산을 투자하여 대비를 할 수 없는 실정이다. 이를 보완하기 위해 본 연구에서는 제방에 대한 수리학적, 지반공학적 위험도, 제방 자체의 성질과 특성을 반영한 취약도를 포함하는 제방 리스크 지도를 작성하여 외수범람에 대한 안전도를 등급화 하였다. 그 결과 침수예상도를 작성하는데 있어 제방 리스크 지도에서 등급이 높은, 즉 리스크가 높은 제방에 대한 재해대책을 수립하는 것이 효율적이다. 본 연구에서는 안성천 유역을 대상으로 제방 리스크 평가를 실시하고, 작성된 제방 리스크 지도를 바탕으로 제방의 붕괴 및 월류시나리오에 대해 1차원 외수범람 해석 및 2차원 침수해석을 실시하여 침수예상도를 작성하였다. 또한 기존의 침수예상도는 침수심에 대한 위험도만을 구분하여 나타내고 있지만, 본 연구에서는 다양한 요소에 대한 침수예상도를 제시함으로써 연구결과물이 재해예방 및 재해경감대책 수립을 위한 기초자료로 활용할 수 있을 것으로 기대된다.

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Comparison and Evaluation on DEM Error by the Resolution of Airborne Laser Scanning Data (항공레이저 측량 자료의 해상도에 따른 DEM 오차 비교평가 연구)

  • Lee, Geun-Sang;Koh, Deuk-Koo;Chae, Hyo-Seok;Shin, Young-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.6 no.3
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    • pp.33-42
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    • 2003
  • As airborne laser scanning technique is developed with high vertical accuracy recently, there come many studies on DEM(digital elevation model creation, building extraction, flood risk mapping and 3D virtual city modeling. This study applied point comparative method, contour comparative method and digital map with scale 1/5,000 to calculate RMSE of DEM in according to resolution that was constructed using rawdata being acquired by airborne laser scanning. As a result, point comparative method showed lower DEM standard error than contour comparative method, it is a reason that contour comparative method was not carried out detailed grid calculation for point comparative method. Also, digital map with scale 1/5,000 showed higher DEM standard error than point comparative method and contour comparative method in below 25.4m that is average horizontal distance among contour line, and showed similar result with contour comparative method in over 25.4m.

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Two-dimensional Inundation Analysis Using Stochastic Rainfall Variation and Geographic Information System (추계학적 강우변동생성 기법과 GIS를 연계한 2차원 침수해석)

  • Lee, Jin-Young;Cho, Wan-Hee;Han, Kun-Yeun;Ahn, Ki-Hong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.1
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    • pp.101-113
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    • 2010
  • Recently actual rainfall pattern is decreasing rainy days and increasing in rainfall intensity and the frequency of flood occurrence is also increased. To consider recent situation, Engineers use deterministic methods like a PMP(Probable Maximum Precipitation). If design storm wouldn't occur, increasing of design criteria is extravagant. In addition, the biggest structure cause trouble with residents and environmental problem. And then it is necessary to study considering probability of rainfall parameter in each sub-basin for design of water structure. In this study, stochastic rainfall patterns are generated by using log-ratio method, Johnson system and multivariate Monte Carlo simulation. Using the stochastic rainfall patterns, hydrological analysis, hydraulic analysis and 2nd flooding analysis were performed based on GIS for their applicability. The results of simulations are similar to the actual damage area so the methodology of this study should be used about making a flood risk map or regidental shunting rout map against the region.

Development of Flood Risk Map Using Two-Dimensional Unstructured Grid-Based Analysis (2차원 비정형 격자기법을 통한 홍수위험지도의 개발)

  • Han, Kun-Yeun;Ahn, Ki-Hong;Cho, Wan-Hee;Kim, Dong-Il
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.357-361
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    • 2008
  • 홍수는 인간이 지구상에 생존하기 전부터 발생하여왔다. 그러나 최근 들어 홍수 규모가 대형화되었고, 그 발생빈도도 증가하고 있다. 최근에는 지구온난화가 가속화 되면서 전 세계적으로 높은 강도의 기상이변들이 속출하고 있다. 우리나라도 예외는 아니어서 지난 100년 동안 기온이 약 $1.5^{\circ}C$ 가량 상승하였고, 집중호우나 태풍과 같은 극단적인 기상현상들로 인한 피해가 날이 갈수록 심해지고 있다. 이러한 이상기후에 따른 태풍, 집중호우 등의 대규모 호우로 인해 댐 및 제방 붕괴와 같은 비상상황이 초래될 수 있다. 잇따른 피해들을 통해 홍수침수 범위의 예측 분석을 통한 홍수위험 및 다양한 홍수위험지도 작성의 필요성이 대두되었다. 본 연구에서는 다양한 종류의 홍수위험지도의 개발을 위해 금호강과 태화강을 대상유역으로 선정하고, 1차원 분석(하천흐름)에는 미국 기상청의 FLDWAV 모형을 적용하였고 2차원 분석(범람흐름)에는 2차원 비정형 격자기법 침수해석 모형을 적용하였다. 1차원 및 2차원 수치해석 모형을 대상유역에 적용한 모의를 통하여 실제 홍수에 대한 제방의 붕괴 및 월류에 따른 유량을 산정하였고, '침수심 지도'와 '홍수유속 지도'를 작성하였으며, 또한 홍수위험 강도를 표현하기 위해 유속과 수심을 이용하여 홍수위험에 대한 '홍수위험강도 지도'를 작성하였다. 다양한 홍수위험지도는 홍수방어대책에 대한 평가와 개발, 또한 개발지역에 대한 선택에 이용될 수 있으며, 실제 홍수시 홍수위험지도에 나타난 긴급대피지역의 모든 주민들에 대해서 피난경고를 미리 발령하는 등의 방법으로 이용이 가능할 것으로 판단된다.

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Study on Application of Diffusion Wave Inundation Analysis Model Linked with GIS (GIS와 연계한 확산파 침수해석 모형의 적용에 대한 연구)

  • Cho, Wan-Hee;Han, Kun-Yeon;Choi, Seung-Yong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.3
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    • pp.88-100
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    • 2009
  • An inundation analysis was performed on Hwapocheon, one of the tributaries of Nakdong River, which was inundated by heavy rain in August, 2002 with overtopping and levee break. The results of the developed model, 2D diffusion wave inundation analysis model, was compared with inundation trace map as well as inundation depth in terms of time and maximum inundated area calculated from FLUMEN model for the assessment of model applicability. The results from the developed model showed high fitness of 88.61% in comparison with observed data. Also maximum inundated area and spatial distribution of inundation zone were also found to be consistent with the results of FLUMEN model. Therefore, inundation zone and maximum inundation area calculated over a period of time by adopting 2D diffusion wave inundation analysis model can be used as a database for identifying high risk areas of inundation and establishing flood damage reduction measures.

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High-Precision and 3D GIS Matching and Projection Based User-Friendly Radar Display Technique (3차원 GIS 정합 및 투영에 기반한 사용자 친화적 레이더 자료 표출 기법)

  • Jang, Bong-Joo;Lee, Keon-Haeng;Lee, Dong-Ryul;Lim, Sanghun
    • Journal of Korea Water Resources Association
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    • v.47 no.12
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    • pp.1145-1154
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    • 2014
  • In recent years, as frequency and intensity of severe weather disasters such as flash flood have been increasing, providing accurate and prompt information to the public is very important and needs of user-friendly monitoring/warning system are growing. This paper introduces a method that re-produces radar observations as multimedia contents and applies reproduced data to mesh-up services. In addition, a accurate GIS matching technique to help to track the exact location going on serious atmospheric phenomena is presented. The proposed method create multimedia contents having structures such as two dimensional images, vector graphics or three dimensional volume data by re-producing various radar variables obtained from a weather radar. After then, the multimedia formatted weather radar data are matched with various detailed raster or vector GIS map platform. Results of simulation test with various scenarios indicate that the display system based on the proposed method can support for users to figure out easily and intuitively routes and degrees of risk of severe weather. We expect that this technique can also help for emergency manager to interpret radar observations properly and to forecast meteorological disasters more effectively.