• Title/Summary/Keyword: flood inundation area

Search Result 254, Processing Time 0.023 seconds

Development of Urban Inundation Analysis Model Using Dual-Drainage Concept (Dual-Drainage 개념에 의한 도시침수해석모형의 개발)

  • Lee, Chang Hee;Han, Kun Yeun;Noh, Joon Woo
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.26 no.4B
    • /
    • pp.379-387
    • /
    • 2006
  • An urban inundation model coupling an one-dimensional stormwater model, SWMM(Storm Water Management Model), and a two-dimensional inundation model was developed to simulate inundation caused by the surcharge of storm sewers in urban areas. The limitation of this model which can not simulate the interaction between drainage systems and surcharged flow was resolved by developing Dual-Drainage inundation analysis model which was based upon hydraulic flow routing procedures for surface flow and pipe flow. The Dual-Drainage inundation analysis model can simulate the effect of complex storm drainage system. The developed model was applied to Dorim, catchment. The computed inundated depth and area have good agreement with the observed data during the flood events. The developed model can help the decision support system of flood control authority for redesigning and constructing flood prevention structures and making the potential inundation zone, and establishing flood-mitigation measures.

Urban Inundation Analysis by Applying with GIS (GIS를 이용한 도시지역 침수해석)

  • Lee, Chang-Hee;Han, Kun-Yeun;Kim, Ji-Sung
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.9 no.2
    • /
    • pp.115-126
    • /
    • 2006
  • The purpose of this study is to develop an urban inundation model using GIS(geographic information system). The model is combining a storm sewer system model and a overland-flow model for the estimation inundation depth in urban area caused by the surcharge of storm sewers. SWMM(storm water management model) was employed to resolve the storm sewer flow and to provide the overflow hydrographs caused by the failure of a drainage system due to the shortage of drainage capacity. The level-pool overland-flow model and DEM based overland-flow model were used to calculate the detail inundation zones and depths due to the surcharge on overland surface. The simulation results can help the decision preventing flood damages by redesigning and enlarging the capacities of storm sewer systems in the inundation-prone areas. The model can also be applied to make the potential inundation area map and establish flood-mitigation measures as a part of the decision support system for flood control authority.

  • PDF

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
    • /
    • v.21 no.5
    • /
    • pp.63-72
    • /
    • 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.

Analysis on Inundation Characteristics for Flood Impact Forecasting in Gangnam Drainage Basin (강남지역 홍수영향예보를 위한 침수특성 분석)

  • Lee, Byong-Ju
    • Atmosphere
    • /
    • v.27 no.2
    • /
    • pp.189-197
    • /
    • 2017
  • Progressing from weather forecasts and warnings to multi-hazard impact-based forecast and warning services represents a paradigm shift in service delivery. Urban flooding is a typical meteorological disaster. This study proposes support plan for urban flooding impact-based forecast by providing inundation risk matrix. To achieve this goal, we first configured storm sewer management model (SWMM) to analyze 1D pipe networks and then grid based inundation analysis model (GIAM) to analyze 2D inundation depth over the Gangnam drainage area with $7.4km^2$. The accuracy of the simulated inundation results for heavy rainfall in 2010 and 2011 are 0.61 and 0.57 in POD index, respectively. 20 inundation scenarios responding on rainfall scenarios with 10~200 mm interval are produced for 60 and 120 minutes of rainfall duration. When the inundation damage thresholds are defined as pre-occurrence stage, occurrence stage to $0.01km^2$, 0.01 to $0.1km^2$, and $0.1km^2$ or more in area with a depth of 0.5 m or more, rainfall thresholds responding on each inundation damage threshold results in: 0 to 20 mm, 20 to 50 mm, 50 to 80 mm, and 80 mm or more in the rainfall duration 60 minutes and 0 to 30 mm, 30 to 70 mm, 70 to 110 mm, and 110 mm or more in the rainfall duration 120 minutes. Rainfall thresholds as a trigger of urban inundation damage can be used to form an inundation risk matrix. It is expected to be used for urban flood impact forecasting.

A Study on the Extraction of Flood Inundated Scar of Rural Small Stream Area Using RADARSAT SAR Images (RADARSAT SAR 영상을 이용한 농촌지역 소하천주변의 침수피해지역 추정 연구)

  • Lee, Mi-Seon;Park, Geun-Ae;Kim, Seong-Joon
    • Journal of Korea Water Resources Association
    • /
    • v.39 no.11 s.172
    • /
    • pp.969-976
    • /
    • 2006
  • The purpose of this study is to trace the flood inundation area around rural small stream by using RADARSAT image because it has the ability of acquiring data during storm period irrespective of rain and cloud. For the storm August 9, 1998 in the Anseong-cheon watershed, three RADARSAT images before, just after and after the storm were used. After ortho-rectification using 5 m DEM, two methods of RGB composition and ratio were tried and found the inundated area in the tributary stream, the Seonghwan-cheon and the Hakjeong-cheon. The inundated area had occurred at the joint area of two streams, thus the floodwater overflowed bounding discharge capacity of the stream. The progression of damage areas were stopped by the local road and farm road along the paddy. The result can be used to acquire the flood inundation data scattered as a small scale in rural area.

Evaluation of Inland Inundation Risk in Urban Area using Fuzzy AHP (Fuzzy AHP 기법을 이용한 도시지역의 내수침수위험도 평가)

  • Shin, Ji Yae;Park, Yei Jun;Kim, Tae-Woong
    • Journal of Korea Water Resources Association
    • /
    • v.47 no.9
    • /
    • pp.789-799
    • /
    • 2014
  • This study presented how to evaluate the inland inundation risk considering the characteristics of inland flood. Fuzzy AHP (Analytic Hierarchy Process), which can deal with the uncertainty or ambiguousness of the decision-making process, was used to estimate the inundation risk. The criteria used for inland inundation risk include the physical index, social index and inland flood. Each index contains three detailed indicators then total nine indicators were employed in this study. The inundation risk evaluation was carried out for each node (manhole) within the drainage system, not to the administrative extent, which enabled us to point out nodes with high risk. The proposed Fuzzy AHP was applied to Geoje district in Busan. The results indicated that the junction of Oncheoncheon and Geojecheon has high risk which is consistent with the fact that this junction has already experienced floods in the past. The proposed method can be used for evaluating inland inundation risk and preparing flood prevention plans in inland flood-prone urban areas.

Inundation Analysis on the Region of Lower Elevation of a New Port by Using SWMM5 and UNET Model - Yongwon-dong, Jinhae-si (SWMM5와 UNET 모형을 이용한 신항만 저지대 침수분석 - 진해시 용원동)

  • Lee, Jung-Min;Lee, Sang-Ho;Kang, Tae-Uk
    • Journal of Korean Society on Water Environment
    • /
    • v.24 no.4
    • /
    • pp.442-451
    • /
    • 2008
  • We analyzed characteristics of rainfall-runoff for the channel of Yongwon area made by a new port construction. And we conducted inundation analysis on the region of lower elevation near the coast. SWMM5 was calibrated with the storm produced by the typhoon Megi from August 19 to August 20 in 2004, and was verified with the storm from August 22 to August 22 in 2004. We performed hydraulic channel routing of Yongwon channel about typhoon Megi from August 19 to August 20 in 2004 by UNET model which is a hydraulic channel routing. The simulated runoff hydrographs were added to the new stream as lateral inflow hydrographs and a watershed runoff hydrograph was the upstream boundary condition. The downstream boundary condition data were estimated by the measured stage hydrographs. The maximum stage that was calculated by hydraulic channel routing was higher than the levee of inundated region in typhoon Megi. Thus we can suppose an inundation to have been occurred. We performed inundation analysis about typhoon Megi from August 19 to August 20 in 2004 and flood discharge of return period 10~150 years. And we estimated each inundation area. The inundation areas by return periods of storms were estimated by 3.4~5.7 ha. The causes of inundation are low heights of levee crests (D.L. 2.033~2.583 m), storm surges induced by typhoons and reverse flow through the coastal sewers (D.L. -0.217~0.783 m). A result of this study can apply to establish countermeasure of a flood disaster in Yongwon.

A Study on the Risk Evaluation of Subway Flood Inundation in Urban Area (도심지역 지하철 침수 위험도 평가에 관한 연구)

  • Kun-Hak Chun;Jong-Cheol Seo ;Hyeon-Gu Choi;Ji-Min Kim
    • Journal of Wetlands Research
    • /
    • v.25 no.2
    • /
    • pp.83-90
    • /
    • 2023
  • Due to climate change, the occurrence of abnormal rainfall is increasing, and the intensity and scale of damage caused by heavy rain are increasing every year. In addition, as the frequency of heavy rains becomes more frequent, heavy rains often occur continuously, resulting in large flooding damage that has never been seen before in urban area. When near rivers and coastal areas are impermeable areas, the maximum flow increases rapidly as the rainfall intensity increases, so a comprehensive flood risk evaluation is needed considering the characteristics of the basin. In this study, the flood inundation risk evaluation was analyzed by giving scores on evaluation factors as a measure to prevent inundation in subway stations. Through the flood inundation risk evaluation process considering the comprehensive evaluation index, the flood risk evaluation was conducted on five urban railway stations with a large amount of traffic and floating population that had been inundated in the past. It is judged that by comprehensively analyzing this and establishing a inundation risk grade (grade 1 to 4) to establish a flood measure suitable for the risk grade.

Real-Time Forecast of Rainfall Impact on Urban Inundation (강우자료와 연계한 도시 침수지역의 사전 영향예보)

  • KEUM, Ho-Jun;KIM, Hyun-Il;HAN, Kun-Yeun
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.21 no.3
    • /
    • pp.76-92
    • /
    • 2018
  • This study aimed to establish database of rainfall inundation area by rainfall scenarios and conduct a real time prediction for urban flood mitigation. the data leaded model was developed for the mapping of inundated area with rainfall forecast data provided by korea meteorological agency. for the construction of data leaded model, 1d-2d modeling was applied to Gangnam area, where suffered from severe flooding event including september, 2010. 1d-2d analysis result agree with observed in term of flood depth. flood area and flood occurring report which maintained by NDMS(national disaster management system). The fitness ratio of the NDMS reporting point and 2D flood analysis results was revealed to be 69.5%. Flood forecast chart was created using pre-flooding database. It was analyzed to have 70.3% of fitness in case of flood forecast chart of 70mm, and 72.0% in case of 80mm flood forecast chart. Using the constructed pre-flood area database, it is possible to present flood forecast chart information with rainfall forecast, and it can be used to secure the leading time during flood predictions and warning.

Empirical Formula for Propagation Distance of Flood Wave-front in Flat Inundation Area without Obstacle due to Levee Breach (장애물이 없는 평탄지형 제내지에서의 범람홍수파 선단 전파거리 실험식 산정)

  • Yoon, Kwang-Seok;Lee, Jong-Kyu
    • Journal of Korea Water Resources Association
    • /
    • v.40 no.10
    • /
    • pp.833-840
    • /
    • 2007
  • The experimental study was carried out to investigate propagation distance of flood wave due to levee breach in a flat inundation area without obstacle. Hitter solution was considered to formulate the experimental results and a representative form was written referring to existing researches. As a result of experiments, it was found that the propagation velocity of the wave front in inundation area was significantly influenced by the initial water level in a channel, which was similar to flow in a channel due to dam break. An empirical formula was also suggested using the experimental results. The dimensionless propagation distance L can be written as the power function of dimensionless time T Coefficients k and m were varied with the dimensionless time T whereas k and m in Ritter solution were 2 and 0, respectively. The variation of coefficients in the relationship between L and T was influenced by the water depth in the inundation area and the fact proved that the changing points of L in the slope of relationship between L and T are the same to those of relationship between the dimensionless maximum water depth in the inundation area, $h_{max}$ and L.