• 제목/요약/키워드: inundation modeling

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Study on Damage Reduction by Flood Inundation and the Sediments by SWAT and HEC-RAS Modeling of Flow Dynamics with Watershed Hydrology - For 27 July 2011 Heavy Storm Event at GonjiamCheon Watershed - (SWAT 및 HEC-RAS 모형의 수문-수리 연계모델링을 통한 곤지암천 유역의 하천범람 및 토사유출 피해저감 연구 - 2011년 7월 27일 국지성 폭우를 대상으로 -)

  • Jung, Chung-Gil;Joh, Hyung-Kyung;Yu, Yeong-Seok;Park, Jong-Yoon;Kim, Seong-Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • 제54권2호
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    • pp.87-94
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    • 2012
  • This study is to evaluate flood inundation and to recommend measures of damage reduction on sediment by concentrated torrential rainfall at Gonjiamcheon Watershed (183.4 $km^2$). Firstly, the SWAT (Soil and Water Assessment Tool) was simulated streamflow and sediment at upstream. Then, we produced a map of floodplain boundary by using HEC-RAS (Hydrologic Engineering Centers River Analysis System) at downstream. The SWAT model was calibrated with 2 years (2008~2009) daily streamflow and validated for another years (2010~2011. 7. 31). The SWAT model was simulated with 3 years (2008~2010) by monthly water quality (Sediment) at Gonjiamcheon water quality station. The streamflow and sediment from SWAT model were input as boundary conditions to HEC-RAS. The results of HEC-RAS indicated that mapping of floodplain boundary was Jiwol and Jiwol 2 district. Additionally, inundation area and depth were assessed and applied BMPs scenario for managing the sediment yield.

Future Inundation Risk Evaluation of Farmland in the Moohan Stream Watershed Based on CMIP5 and CMIP6 GCMs (CMIP5 및 CMIP6 GCM 기반 무한천 유역 농경지 미래 침수 위험도 분석)

  • Jun, Sang Min;Hwang, Soonho;Kim, Jihye;Kwak, Jihye;Kim, Kyeung;Lee, Hyun Ji;Kim, Seokhyeon;Cho, Jaepil;Lee, Jae Nam;Kang, Moon Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • 제62권6호
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    • pp.131-142
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    • 2020
  • The objective of this study was to evaluate future inundation risk of farmland according to the application of coupled model intercomparison project phase 5 (CMIP5) and coupled model intercomparison project phase 6 (CMIP6). In this study, future weather data based on CMIP5 and CMIP6 general circulation model (GCM) were collected, and inundation was simulated using the river modeling system for small agricultural watershed (RMS) and GATE2018 in the Tanjung district of the Moohan stream watershed. Although the average probable rainfall of CMIP5 and CMIP6 did not show significant differences as a result of calculating the probability rainfall, the difference between the minimum and maximum values was significantly larger in CMIP6. The results of the flood discharge calculation and the inundation risk assessment showed similar to trends to those of probability rainfall calculations. The risk of inundation in the future period was found to increase in all sub-watersheds, and the risk of inundation has been analyzed to increase significantly, especially if CMIP6 data are used. Therefore, it is necessary to consider climate change effects by utilizing CMIP6-based future weather data when designing and reinforcing water structures in agricultural areas in the future. The results of this study are expected to be used as basic data for utilizing CMIP6-based future weather data.

Development of the wet and dry treatment using quadtree grids (사면구조 격자를 이용한 이동경계 기법 개발)

  • Kim, Jong-Ho;Lee, Seung-Oh;Cho, Yong-Sik
    • 한국방재학회:학술대회논문집
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    • 한국방재학회 2008년도 정기총회 및 학술발표대회
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    • pp.183-186
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    • 2008
  • All measures to cope with flooding rely on flood predictions to some extent, and the effectiveness of these measures is dependent on the quality of flood predictions. It is important to track properly the movements of the river-bankline in numerical modeling because the location of it varies continuously in the flood inundation. In this study, the wet and dry treatment is used to describe the moving river-bankline accurately (Cho, 1996). An oscillatory flow motion in a parabolic basin is used to validate the performance of the developed model based on quadtree grids. As a result of a simulation, a reasonable agreement is observed with analytical and Cho's results.

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Simulation and analysis of urban inundation using the integrated 1D-2D urban flood model (1D-2D 통합 도시 침수 해석 모형을 이용한 침수 원인 분석에 관한 연구)

  • Lee, Seungsoo;Noh, Seong Jin;Jang, Cheolhee;Rhee, Dong Sop
    • Journal of Korea Water Resources Association
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    • 제50권4호
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    • pp.263-275
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    • 2017
  • Integrated numerical approaches with physically-based conceptualization are required for accurate urban inundation simulation. In this study, we described, applied and analyzed an integrated 1-dimensional (1D) sewerage system and 2-dimensional (2D) surface flow model, which was suggested by Lee et al. (2015). This model was developed based on dual-drainage concept, and uses storm drains as an discharge exchange spot rather than manholes so that interaction phenomena between surface flow and sewer pipe flow are physically reproduced. In addition, the building block concept which prevents inflows from outside structures is applied in order to consider building effects. The capability of the model is demonstrated via reproducing the past flooding event at the Sadang-cheon River catchment, Seoul, South Korea. The results show the plausible causes of the inundation could be analysed in detail by integrated 1D-2D modeling.

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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    • 제49권9호
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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.

Modeling flood and inundation in the lower ha thanh river system, Binh dinh province, vietnam

  • Don, N. Cao;Hang, N.T. Minh
    • Proceedings of the Korea Water Resources Association Conference
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    • 한국수자원학회 2016년도 학술발표회
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    • pp.195-195
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    • 2016
  • Kon - Ha Thanh River basin is the largest and the most important river basin in Binh Dinh, a province in the South Central Coast of Vietnam. In the lower rivers, frequent flooding and inundation caused by heavy rains, upstream flood and or uncontrolled flood released from upstream reservoirs, are very serious, causing damage to agriculture, socio-economic activity, human livelihood, property and lives. The damage is expected to increase in the future as a result of climate change. An advanced flood warning system could provide achievable non-structural measures for reducing such damages. In this study, we applied a modelling system which intergrates a 1-D river flow model and a 2-D surface flow model for simulating hydrodynamic flows in the river system and floodplain inundation. In the model, exchange of flows between the river and surface floodplain is calculated through established links, which determine the overflow from river nodes to surface grids or vice versa. These occur due to overtopping or failure of the levee when water height surpasses levee height. A GIS based comprehensive raster database of different spatial data layers was prepared and used in the model that incorporated detailed information about urban terrain features like embankments, roads, bridges, culverts, etc. in the simulation. The model calibration and validation were made using observed data in some gauging stations and flood extents in the floodplain. This research serves as an example how advanced modelling combined with GIS data can be used to support the development of efficient strategies for flood emergency and evacuation but also for designing flood mitigation measures.

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The Effect of Uncertainty in Roughness and Discharge on Flood Inundation Mapping (조도계수와 유량의 불확실성이 홍수범람도 구축에 미치는 영향)

  • Jung, Younghun;Yeo, Kyu Dong;Kim, Soo Young;Lee, Seung Oh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제33권3호
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    • pp.937-945
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    • 2013
  • The accuracy of flood inundation maps is determined by the uncertainty propagated from all variables involved in the overall process including input data, model parameters and modeling approaches. This study investigated the uncertainty arising from key variables (flow condition and Manning's n) among model variables in flood inundation mapping for the Missouri River near Boonville, Missouri, USA. Methodology of this study involves the generalized likelihood uncertainty estimation (GLUE) to quantify the uncertainty bounds of flood inundation area. Uncertainty bounds in the GLUE procedure are evaluated by selecting two likelihood functions, which is two statistic (inverse of sum of squared error (1/SAE) and inverse of sum of absolute error (1/SSE)) based on an observed water surface elevation and simulated water surface elevations. The results from GLUE show that likelihood measure based on 1/SSE is more sensitive on observation than likelihood measure based on 1/SAE, and that the uncertainty propagated from two variables produces an uncertainty bound of about 2% in the inundation area compared to observed inundation. Based on the results obtained form this study, it is expected that this study will be useful to identify the characteristic of flood.

Method for Flood Runoff Analysis of Main Channel Connected with Interior Floodplain : I. Application for Analysis of Inundation Area in Interior Floodplain (제내지와 하도를 연계한 하천유역의 홍수유출해석: I. 제내지 침수해석에의 적용)

  • Jang, Su Hyung;Yoon, Jae Young;Yoon, Yong Nam;Kim, Won Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제26권1B호
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    • pp.79-88
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    • 2006
  • In this study, a methodology is developed for flood runoff analysis considering the interaction between interior floodplain and channel. Riparian lowland is modeled as storage areas by HEC-RAS and is connected with main channel through gravity drainage structure and pumping stations. As a result, we were able to compute the difference between runoff into the interior floodplain and delayed runoff to main channel from interior floodplain. This allowed us to compute the storage change in the interior floodplain and corresponding inundation areas. Furthermore, the levee is modeled as a lateral structure and the flood from the main channel to interior floodplain is modeled by installing a weir on top of it. In addition, levee breach is also modeled so that flooding from main channel to interior floodplain can be considered. Computed flooding depth in the storage areas are compared with elevation to identify the inundated areas and flood maps can then be produced for a desired time or for the extent of flooding given a flooding depth. Output from this modeling effort can provide many useful information for flood planning such as flow depth in main channel, flooding depth and area in interior floodplain. The method was applied to Sapgyo river basin and the comparison with observed flood events showed that it can reproduce the observation fairly well, hence proving the utility of the method.

A Study on the Effectiveness of Radar Rainfall by Comparing with Flood Inundation Record Map Using KIMSTORM (Grid-based KIneMatic Wave STOrm Runoff Model) (분포형 강우유출모형 KIMSTORM을 이용한 침수실적자료와의 비교를 통한 레이더강우의 효용성 연구)

  • Ahn, So Ra;Jung, Chung Gil;Kim, Seong Joon
    • Journal of Korea Water Resources Association
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    • 제48권11호
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    • pp.925-936
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    • 2015
  • The purpose of this study is to explore the effectiveness of dual-polarization radar rainfall by comapring with the flood inundation record map through KIMSTORM(Grid-based KIneMatic wave STOrm Runoff Model). For Namgang dam ($2,293km^2$) watershed, the Bisl dual-polarization radar data for 3 typhoons (Khanun, Bolaven, Sanba) and 1 heavy rain event in 2012 were prepared. For both 28 ground rainfall data and radar rainfall data, the model was calibrated using observed discharge data at 5 stations with $R^2$, Nash and Sutcliffe Model Efficiency (ME) and Volume Conservation Index (VCI). The calibration results of $R^2$, ME and VCI were 0.85, 0.78 and 1.09 for ground rainfall and 0.85, 0.79, and 1.04 for radar rainfall respectively. The flood inundation record areas (SY and MD/SG district) by typhoon Sanba were compared with the distributed modeling results. The spatial distribution by radar rainfall produced more surface runoff from the watershed and simulated higher stream discharge than the ground rainfall condition in both SY and MD/SG district. In case of MD/SG district, the stream water level by radar rainfall near the flood inundation area showed 0.72 m higher than the water level by ground rainfall.

Development and Verification of Inundation Modeling with Urban Flooding Caused by the Surcharge of Storm Sewers (도시배수체계와 연계한 내수침수모형의 개발 및 검증)

  • Kim, Ji-Sung;Han, Kun-Yeun;Lee, Chang-Hee
    • Journal of Korea Water Resources Association
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    • 제39권12호
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    • pp.1013-1022
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    • 2006
  • Urban flooding is usually caused by the surcharge of storm sewers. For this reason, previous studies on urban flooding are mainly concentrated on the simulation of urban drainage systems. However these approaches that find the pipes which have insufficient drainage capacity are very approximate and unreasonable ways in establishing both flood prevention and flood-loss reduction planning. In this study, a two-dimensional model linked the existing ILLUDAS model is developed to calculate the accurate and resonable solution about urban flood inundation and it is verified by using the simulation of July 2001 flood in Seoul. In the urban area with a small difference of ground elevations, the two-dimensional flood propagation phases must be considered to make a accurate analysis for inundated area and depth. The result of this study can be used to construct fundamental data for a flood control plan and establish a urban flood forecasting/warning system.