• Journal of Korea Water Resources Association
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• v.45 no.11
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• pp.1093-1105
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• 2012

In this study, the simulations and analyses of flood flow due to a river inundation in a coastal urban area are carried out using a two-dimensional finite volume model with well-balanced HLLC scheme. The target area is a coastal urban area around Gohyun river which is located at Geoje city in Kyungnam province and was extremely damaged due to the heavy rainfall during the period of the typhoon "Maemi" in September 2003. For the purpose of the verification of the numerical model applied in this study, the simulated results are compared and analyzed with the inundation traces. In addition, the flood flow in an urban area is simulated and analyzed according to the scenarios of inflow variation due to the increase and decrease of the intensity of the heavy rainfall, which.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.292-299
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• 2014

Since most of the researches on the coastal inundation due to typhoons have considered only storm surges, an additional inundation due to rainfall has been neglected. In general, typhoons are natural disasters being accompanied by the rainfall. Thus, it is essential to consider the effect of rainfall in the numerical simulation of coastal inundation due to storm surges. Because the rainwater is discharged to the sea through the storm sewer system, it should be included in the numerical simulation of storm surges to obtain reasonable results. In this study an algorithm that can deal with the effects of rainfall and sewer system is developed and combined with a conventional storm surge numerical model. To test the present numerical model various numerical simulations are conducted using the simplified topography for the cases including the inundation due to rainfall, the drainage of rainwater, the backflow of sea water, and the increase of sea water level due to drainage of rainwater. As a result, it is confirmed that the basic performance of the present model is satisfactory for various flow situations.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.29-36
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• 2015

Current domestic research is to demonstrate the effectiveness and efficiencies of flood prevention measures through one-dimensional numerical analysis and this study's object is to help water managers to make the efficient decisions by applying the two-dimensional urban run off model XP-SWMM model in the flooded area and comparing with the flood prevention measures. Statistics were analyzed, based on the data collected from Cheongju Weather Service from 1967 to 2011 for 45 years. 50 years Flood frequency simulations of water flow capacity analysis of the target area for flooded areas $539,548m^2$, inundation depth 1.0 m, was analyzed by inundation time of 48 minutes. When comparing with the constructions of bypass road and underground storage facilities to increase the water flow capacity of A1 small drainage areas as flood protection, if you install a batching target underground detention basin with a capacity of $13,500m^3$, it is expected that the flood by rainfall with frequency of 50 years will be resolved completely. In preparation for extreme weather in the future flood mitigation measures, underground storage tank installation is considered a better efficient way.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.4
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• pp.348-359
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• 2006

The city of Mokpo suffers lowland inundation damages by sea water flooding even without harsh weather like a typhoon, due to the low level urban infrastructure facilities, oceanic environmental changes by constructions of seadike/seawall and sea level rise caused by global warming. This study performs constructing the simulation system which employs the MIKE21 software. And the system is applied to several typhoon- induced surges which had resulted in inundation at Mokpo. Virtual situation of flooding is simulated in case 59 cm of surge height, which had been occurred actually by RUSA(0215), coincides with Approx. H.H.W. Then the water level of 545 cm corresponds to the extreme high water level(544 cm) for 10 year return period after the construction of Geumho seawall. The results show rapid and broad inundation at Inner-Port, requiring additional preparations for flood protections.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.21-34
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• 2006

The simulation of tsunami inundation using detailed bathymetry and topography is required to establish the countermeasure of disaster mitigation and the tsunami hazard map. In this study, a simulation of the 1983 tsunami event in the East Sea using parallel finite element model, which is possible to simulate with suitable accuracy by the Beowulf parallel computation method, is performed to produce detailed features of coastal inundation. Results of simulations are compared with measured data. The evolution of statistic distribution of tsunami heights is studied numerically and the distribution functions of tsunami heights show a tendency to the log-normal curve along coastal area.

• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.355-364
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• 2005

In this study, flood inundations have been simulated by using the numerical model FLUMEN solving the shallow-water equations with a finite volume method. Before applying to a real problem, the numerical model is first applied to simplified problems. Obtained numerical results are verified by comparing with available analytical solutions and laboratory measurements. Reasonable agreements are observed. The model is then applied to a simulation of flood events with real geometries. The results of this study will provide basic information to make a flood inundation map.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.389-393
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• 2010

The Objective of this study was to develop a system for visualizing inundation area by using 1-D numerical model analyzing damage information such as inundation area, facilities, land usages, population, building, loads. In this study, we have reviewed hydraulic models to select a flood model for simulation of discharges, water depths and velocities. The study area is Namhan River from Youngwol to Paldang Dam which had a flood damage on upper and below regions of Chungju Dam by a storm event in 2006. At the first, we developed the DB system base on GIS thematic map, ortho images, cadastral maps to analyze flood damages and support decisions making. Changing the boundary conditions such as discharge at the gauging stations, flood simulations were performed and then damages were extracted from the databases information support system based on 1-D numerical hydraulic model, it is expected to be able to analyze flood damages and support a decision making for reduce flood relate damages. In the future, the system developed in this study could be applied for flood forecasting system of small scaled streams.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.397-397
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• 2015

The frequency of urban floods is recently increased as a consequence of climate change and haphazard development in urban area. To mitigate and prevent the flood damage, we generally utilized a numerical model to investigate the causes and risk of urban flood. Contrary to general flood inundation model simulating only the surface flow, the model needs to consider flow of the sewer network system like SWMM and ILLUDAS. However, this kind of model can not consider the interaction between the surface flow and drainage network. Therefore, we tried to evaluate the impact of bidirectional interaction between sewer and surface flow in urban flooding analysis based on simulations using the quasi-interacted model and the interacted model. As a general quasi-interacted model, SWMM5 and FLUMEN are utilized to analyze the flow of drainage network and simulate the inundation area, respectively. Then, FLO-2D is introduced to consider the interaction between the surface flow and sewer system. The two method applied to the biggest flood event occurred in July 2011 in Sadang area, South Korea. Based on the comparison with observation data, we confirmed that the model considering the interaction the sewer network and surface flow, showed a good agreement than the quasi-interacted model.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.707-710
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• 2008

Recently, a rivers' bridge that locate on among the mountains area is destroyed by debris accumulation and debris flow, because of frequent occurrence of typhoon and a localized torrential downpour. therefore a river make a part of dam's effect. Actually, this situation gives damages like inundation of a bridge upper stream area's. Generally, It the main cause of the occurrence route of the debris accumulation is that outbreaks of driftwood and debris flow because of landslide, that occurred by severe rain storm. Also, a lot of debris are occurred when big flood come up during long period at this time, this kind of debris accumulation remove to other place, in several, and specially, debris accumlation move to the place where the depth of water is deep and velocity is fast river center. According to these kind of fact, this research put in effect and analyze that movement characteristic's numerical simulations of debris accumulation at flood according to a domestic outside literature investigation, on-site monitoring survey and parameter scenario which comes out through the hydraulic modeling analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.997-1005
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• 2013

Since the cross-sectional shape of the Nakdong river is compound type, the water stage rises up to the top of the flood plane, as the flow discharge increases during the extreme rain storm in summer. The recent increase of rainfall intensity and flood frequency results in the immersions of parks and hydrophilic facilities located in the flood plain. Therefore it is necessary to analyze the hydraulic characteristics evolved by the extreme rain storm in the flood plain. The study reach ranging from the Gangjeong Goryeong Weir and the Dalseong Weir, where several hydraulic facilities are located along the channel, was selected and numerical simulations were conducted for 42 hours including the peak flood of the typhoon Sanba. The 2-D transient model, FaSTMECH was employed and the accuracy of the model was assessed by comparing the water level between the simulation results and the measured ones at a gauging station. It showed a high correlation with $R^2$ of 0.990, AME of 0.195, and RMSE of 0.252. In addition, the inundation time, the inundation depth, the inundation velocity, and the shear stress variation in the flood plain facilities were analyzed.