• Title/Summary/Keyword: Flood risk assessment

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Urban Flood Regional Safety Assesment Model (도시지역 홍수재해에 대한 지역안전도 평가모형)

  • Lee, Chang-Hee;Lee, Suk-Min;Shin, Sang-Young;Yeo, Chang-Geon;Kim, Youn-Jong
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.376-379
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    • 2007
  • In recent years, the natural damage associated with flood disaster has been dramatically increased. However, there is no rational method which reflects urban characteristics to estimate the regional safety assessment for flood disaster. The purpose of this study is to develop the regional safety assesment model for urban flood. Flood risk and reduction assesment were estimated by using the linear sum of the Z score of the assessment factors and the weight value of each factor from the expert survey data. And then the regional safety assessment was estimated by subtracting reduction factor value from risk factor value. GIS tool was used to estimate the factor assesment and integrated regional safety. This study can be used to determine the priority of flood protection project, execute the flood insurance and establish the urban plans and the flood mitigate plan.

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UNCERTAINTY IN DAM BREACH FLOOD ROUTING RESULTS FOR DAM SAFETY RISK ASSESSMENT

  • Lee, Jong-Seok
    • Water Engineering Research
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    • v.3 no.4
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    • pp.215-234
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    • 2002
  • Uncertainty in dam breach flood routing results was analyzed in order to provide the basis fer the investigation of their effects on the flood damage assessments and dam safety risk assessments. The Monte Carlo simulation based on Latin Hypercube Sampling technique was used to generate random values for two uncertain input parameters (i.e., dam breach parameters and Manning's n roughness coefficients) of a dam breach flood routing analysis model. The flood routing results without considering the uncertainty in two input parameters were compared with those with considering the uncertainty. This paper showed that dam breach flood routing results heavily depend on the two uncertain input parameters. This study indicated that the flood damage assessments in the downstream areas can be critical if uncertainty in dam breach flood routing results are considered in a reasonable manner.

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Flood Risk Assessment Based on Bias-Corrected RCP Scenarios with Quantile Mapping at a Si-Gun Level (분위사상법을 적용한 RCP 시나리오 기반 시군별 홍수 위험도 평가)

  • Park, Jihoon;Kang, Moon Seong;Song, Inhong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.4
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    • pp.73-82
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    • 2013
  • The main objective of this study was to evaluate Representative Concentration Pathways (RCP) scenarios-based flood risk at a Si-Gun level. A bias correction using a quantile mapping method with the Generalized Extreme Value (GEV) distribution was performed to correct future precipitation data provided by the Korea Meteorological Administration (KMA). A series of proxy variables including CN80 (Number of days over 80 mm) and CX3h (Maximum precipitation during 3-hr) etc. were used to carry out flood risk assessment. Indicators were normalized by a Z-score method and weighted by factors estimated by principal component analysis (PCA). Flood risk evaluation was conducted for the four different time periods, i.e. 1990s, 2025s, 2055s, and 2085s, which correspond to 1976~2005, 2011~2040, 2041~2070, and 2071~2100. The average flood risk indices based on RCP4.5 scenario were 0.08, 0.16, 0.22, and 0.13 for the corresponding periods in the order of time, which increased steadily up to 2055s period and decreased. The average indices based on RCP8.5 scenario were 0.08, 0.23, 0.11, and 0.21, which decreased in the 2055s period and then increased again. Considering the average index during entire period of the future, RCP8.5 scenario resulted in greater risk than RCP4.5 scenario.

Comparative analysis of inundation flow patterns and flood risk assessment methods within subway stations (지하철 역사 내 침수 흐름 분석 및 침수 위험도 평가 방법 비교)

  • Shin, Jaehyun;Kim, Minjeong;Cho, Inhwan;Park, Inhwan
    • Journal of Korea Water Resources Association
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    • v.56 no.10
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    • pp.667-678
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    • 2023
  • In this study, quasi-3D inundation flow simulations were conducted for a simplified subway station configuration. The effects of variations in rainwater inflow locations and discharge were investigated, analyzing the resulting inundation flow patterns and flood risk. The inundation simulation results calculated the incipient velocities for slipping and toppling accidents to assess pedestrian safety. The results indicated that velocities exceeding the incipient velocity for slipping accidents mainly occurred on the flooded staircase. Meanwhile, velocities surpassing the incipient toppling accidents were observed around the staircase and the corridor near the staircase leading to B2F. This observation is consistent with the results from the specific force distribution analysis. To provide detailed flood risk assessments, the Flood Hazard Degree (FD) was applied with four levels of criteria, along with the Flood Intensity Factor (FIF). The results demonstrated that FD identified a broader area at risk of flood-induced consequences compared to FIF. When comparing the different inundation risk assessment methods, the specific force method tended to overestimate the risk area, whereas FIF tended to underestimate it. Furthermore, among all assessment methods, the influence of rainwater discharge was found to have a more dominant effect on flood risk assessment compared to the number of rainwater inflow locations. Additionally, the direction of inundation flow influenced the assessed risk, with collision-induced flow patterns leading to higher flood risk than those with identical flow directions.

Development of flood hazard and risk maps in Bosnia and Herzegovina, key study of the Zujevina River

  • Emina, Hadzic;Giuseppe Tito, Aronica;Hata, Milisic;Suvada, Suvalija;Slobodanka, Kljucanin;Ammar, Saric;Suada, Sulejmanovic;Fehad, Mujic
    • Coupled systems mechanics
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    • v.11 no.6
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    • pp.505-524
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    • 2022
  • Floods represent extreme hydrological phenomena that affect populations, environment, social, political, and ecological systems. After the catastrophic floods that have hit Europe and the World in recent decades, the flood problem has become more current. At the EU level, a legal framework has been put in place with the entry into force of Directive 2007/60/EC on Flood Risk Assessment and Management (Flood Directive). Two years after the entry into force of the Floods Directive, Bosnia and Herzegovina (B&H), has adopted a Regulation on the types and content of water protection plans, which takes key steps and activities under the Floods Directive. The "Methodology for developing flood hazard and risk maps" (Methodology) was developed for the territory of Bosnia and Herzegovina, following the methodology used in the majority of EU member states, but with certain modifications to the country's characteristics. Accordingly, activities for the preparation of the Preliminary Flood Risk Assessment for each river basin district were completed in 2015 for the territory of Bosnia and Herzegovina. Activities on the production of hazard maps and flood risk maps are in progress. The results of probable climate change impact model forecasts should be included in the preparation of the Flood Risk Management Plans, which is the subsequent phase of implementing the Flood Directive. By the foregoing, the paper will give an example of the development of the hydrodynamic model of the Zujevina River, as well as the development of hazard and risk maps. Hazard and risk maps have been prepared for medium probability floods of 1/100 as well as for high probability floods of 1/20. The results of LiDAR (Light Detection and Ranging) recording were used to create a digital terrain model (DMR). It was noticed that there are big differences between the flood maps obtained by recording LiDAR techniques in relation to the previous flood maps obtained using georeferenced topographic maps. Particular attention is given to explaining the Methodology applied in Bosnia and Herzegovina.

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.

Development and the Application of Flood Disaster Risk Reduction Index (홍수피해저감지수(FDRRI) 개발 및 시범적용)

  • Moon, Seung-Rok;Yang, Seung-Man;Choi, Seon-Hwa
    • Journal of the Korean Society of Safety
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    • v.29 no.1
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    • pp.64-69
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    • 2014
  • Community-based disaster preparedness approaches are increasingly important elements of vulnerability reduction and disaster strategies. They are associated with a policy trend that values the knowledge and capacities of local people. In this research, we describe the community diagnosis method and develop Flood Disaster Risk Reduction Index(FDRRI) for assessment of flood vulnerability. FDRRI is composed of four indicators such as Flood Exposure Indicator(FEI), Sensitivity Indicator(SI), Risk Reduction Indicator(RRI), and Community Preparedness Indicator(CPI). We anticipate to present the guideline for selection national preparedness projects and uplift community's preparedness capacity.

Development of Flood Risk Index using causal relationships of Flood Indicators (홍수지표의 인과관계를 이용한 홍수위험지수 개발)

  • Lim, Kwang Suop;Choi, Si Jung;Lee, Dong Ryul;Moon, Jang Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1B
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    • pp.61-70
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    • 2010
  • This research presents a methodology to define and apply appropriate index that can measure the risk of regional flood damage. Pressure-State-Response structure has been used to develop the Flood Risk Index(FRI), which allows for a comparative analysis of flood risk assessment between different sub-basins. FRI is a rational assessment method available to improve disaster preparedness and the prevention of losses. The pressure and state index for flood at 117 sub-basins from the year 1980s until the t 10s showed proportional relations, but state index did not decrease even though response index increased. This shows that pressures for flood damage relatively exceed countermeasure for flood. Thus this means we need to strengthen design criteria for flood countermeasure in the future. The FRI is gradually going down in consequence of continuous flood control projects. Flood risk of Han River and Nakdong River area is relatively lower than that of Geum, Seumjin, and Youngsan River area.

Evaluating Flood Risk Area using GIS and RADARSAT Data-A Case Study in Northeast Thailand

  • Mongkolsawat, C.;Thirangoon, P.;Suwanwerakamtorn, R.;Karladee, N.;Paiboonsak, S.
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.7-9
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    • 2003
  • The objective of this study is to evaluate flood risk area by integrating GIS and RADARSAT data. The study area, Northeast Thailand, is subject to flood during the rainy season. The main data used in this evaluation included RADARSAT data, landform and topographic map. The evaluation was conducted by overlay operation of flood area in 2001, land form and buffer region beyond the flood areas with the selection criteria defined. Most of the flood risk areas were found in the low lying land form within the buffer region. The cloud penetrating capabilities of SAR is only a source of information for effectively assessment of flood risk area in Northeast Thailand.

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Urban Flood Risk Assessment Considering Climate Change Using Bayesian Probability Statistics and GIS: A Case Study from Seocho-Gu, Seoul (베이지안 확률통계와 GIS를 연계한 기후변화 도시홍수 리스크 평가: 서울시 서초구를 대상으로)

  • LEE, Sang-Hyeok;KANG, Jung-Eun;PARK, Chang-Sug
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.4
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    • pp.36-51
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    • 2016
  • This study assessed urban flood risk using a Bayesian probability statistical method and GIS incorporating a climate change scenario. Risk is assessed based on a combination of hazard probability and its consequences, the degree of impact. Flood probability was calculated on the basis of a Bayesian model and future flood occurrence likelihoods were estimated using climate change scenario data. The flood impacts include human and property damage. Focusing on Seocho-gu, Seoul, the findings are as follows. Current flood probability is high in areas near rivers, as well as low lying and impervious areas, such as Seocho-dong and Banpo-dong. Flood risk areas are predicted to increase by a multiple of 1.3 from 2030 to 2050. Risk assessment results generally show that human risk is relatively high in high-rise residential zones, whereas property risk is high in commercial zones. The magnitude of property damage risk for 2050 increased by 6.6% compared to 2030. The proposed flood risk assessment method provides detailed spatial results that will contribute to decision making for disaster mitigation.