• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.58-66
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• 2016

This study aims to estimate the failure probability of concrete gravity dams for their risk analysis under flood situation. To the end, failure modes of concrete gravity dams and their limit state functions are proposed based on numerous review of domestic and international literatures on the dam failure cases and design standards. Three failure modes are proposed: overturning, sliding, and overstress. Based on the failure modes the limit state functions, the failure probability is assessed for a weir section and a non-weir section of a dam in Korea. As water level is rising from operational condition to extreme flood condition, the failure probability is found to be raised up to the warning condition, especially for overturning mode at the non-weir section. The result can be used to reduce the risk of the dam by random environmental variables under possible flood situation.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.236-236
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• 2015

Flood is one of the major natural disasters affecting millions of people. Thailand also, frequently faces with this type of disaster. Especially, 2011 mega flood in Central Thailand, inundated highway severely attributed to the failure of national economic and risk to life. Lesson learned from such an extreme event caused flood monitoring and warning becomes one of the sound mitigations. The highway flood hazard mapping accomplished in this research is one of the strategies. This is due to highway flood is the potential risk to life and limb, and potential damage to property. Monitoring and warning therefore help reducing live and property losses. In this study, degree of highway flood hazard was assessed by weighting factors for each cause of the highway flood using Multi Criteria Analysis (MCA) based Analytic Hierarchy Process (AHP). These weighting factors are the essential information to classify the degree of highway flood hazard to enable pinpoint on flood monitoring and flood warning in hazard areas. The highway flood causes were then investigated. It was found that three major factors influence to the highway flood are namely the highway characteristics, the hydrological characteristics and the land topography characteristics. The weight of importance for each cause of the highway flood in the whole country was assessed by weighting 3 major factors influence to the highway flood. According to the result of MCA analysis, the highway, the hydrological and the land topography characteristics were respectively weighted as 35, 35 and 30 percent influence to the cause of highway flood. These weighting factors were further utilized to classify the degree of highway flood hazard. The Weight Linear Combination (WLC) method was used to compute the total score of all highways according to each factor. This score was later used to categorize highway flood as high, moderate and low degree of hazard levels. Highway flood hazard map accomplished in this research study is applicable to serve as the handy tool for highway flood warning. However, to complete the whole warning process, flood water level monitoring system for example the camera gauge should be installed in the hazard highway. This is expected to serve as a simple flood monitor as part of the warning system during such extreme or critical event.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.335-337
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• 2021

Flood damage is occurring all over the world, and the number of people living in flood-prone areas reached 86 million, a 25% increase compared to 2000. These floods cause enormous damage to life and property, and it is essential to decide on an appropriate evacuation in order to reduce the damage. Evacuation in anticipation of a flood also incurs a lot of cost, and if an evacuation is not performed due to an error in the flood prediction, a greater cost is incurred. Therefore, in this paper, we propose a flood risk determination model using the CNN model to enable evacuation at an appropriate time by using the time series data of precipitation and water level. Through this, it is thought that it can be utilized as an initial study to determine the time of flood evacuation to prevent unnecessary evacuation and to ensure that evacuation can be carried out at an appropriate time.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2293-2302
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• 2013

Flood inundation map has been used as a fundamental information in flood risk management. However, there are various sources of uncertainty in flood inundation mapping, which can be another risk in preventing damage from flood. Therefore, it is necessary to remove or reduce uncertainty sources to improve the accuracy of flood inundation maps. However, the entire removal of uncertainty source may be impossible and inefficient due to limitations of knowledge and finance. Sensitivity analysis of uncertainty sources allows an efficient flood risk management by considering various conditions in flood inundation mapping because an uncertainty source under different conditions may propagate in different ways. The objectives of this study are (1) to perform sensitivity analysis of uncertainty sources by different conditions on flood inundation map using the FOA method and (2) to find a major contributor to a propagated uncertainty in the flood inundation map in Flatrock at Columbus, U.S.A. Result of this study illustrates that an uncertainty in a variable is differently propagated to flood inundation map by combination with other uncertainty sources. Moreover, elevation error was found to be the most sensitive to uncertainty in the flood inundation map of the study reach.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.91-95
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• 2014

During a flood season, Bo region could be easily exposed to flood due to increase of ground water level and the water drain difficulty even the water amount of Bo can be managed. GFI for the flood risk is measured by mean depth to water during a dry season and minimum depth to water and tangent degree during a flood season. In this paper, a forecasting model of the target variable, GFI and predictors as differences of height between ground water and Bo water, distances from water resource, and soil characteristics are obtained for the dry season of 2012 and the flood season of 2012 with empirical data of Gangjungbo and Hamanbo. Obtained forecasting model would be used for keep the value of GFI below the maximum allowance for no flooding during flooding seasons with controlling the values of significant predictors.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.68-77
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• 2011

Flood disasters on the metropolis where population and facilities were densely concentrated cause an enormous damage, therefore it is important to find risk and vulnerable area for floods, and then mid-long term disaster reduction plan should be established by the results. However, there is no rational method which reflects urban characteristics to estimate the regional safety for flood. so it is necessary to develop the standardized method of regional safety assesment due to urban flood. The proposed regional safety assesment model in this study was combined risk and mitigation score which consisted of three and two element, and 12 assesment factors which effect flood disasters were selected. And then the integrated regional safety was estimated by subtracting mitigation score from risk score. GIS tool was used to estimate the factor assesment and integrated regional safety. Developed regional safety assesment model was applied in Seoul to evaluate the suitability.

• Journal of Korea Water Resources Association
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• v.49 no.9
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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.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.125-133
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• 2019

In this paper, probabilistic flood risk maps were produced for levee break caused by possible flood scenarios. The results of the previous studies were employed for flood stages corresponding to hydrological extreme event quantified uncertainties and then predicted the location of a levee breach. The breach width was estimated by combining empirical equation considered constant width and numerical modeling considered uncertainties on compound geotechnical component. Accordingly, probabilistic breach outflow was computed and probabilistic inundation map was produced by 100 runs of 2D inundation simulation based on reliability analysis. The final probabilistic flood risk map was produced by combining probabilistic inundation map based on flood hazard mapping methodology. The outcomes of the study would be effective in establishing specified emergency actin plan (EAP) and expect to suggest more economical and stable design index.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.341-346
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• 2022

Due to global warming and abnormal climate, the frequency and damage of floods are increasing, and the number of people exposed to flood-prone areas has increased by 25% compared to 2000. Floods cause huge financial and human losses, and in order to reduce the losses caused by floods, it is necessary to predict the flood in advance and decide to evacuate quickly. This paper proposes a flood risk determination model using a CNN-based classification model so that timely evacuation decisions can be made using rainfall and water level data, which are key data for flood prediction. By comparing the results of the CNN-based classification model proposed in this paper and the DNN-based classification model, it was confirmed that it showed better performance. Through this, it is considered that it can be used as an initial study to determine the risk of flooding, determine whether to evacuate, and make an evacuation decision at the optimal time.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.183-194
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• 2019

In recent years, the risk of external flooding of major national facilities has increased significantly since 2000 due to the increase in local heavy rainfall events. For important domestic national facilities, it is necessary to analyze the risk of external flooding as flooding in major sites due to heavy rain can cause functional paralysis in major facilities and ultimately lead to massive trouble events. In order to manage the safety of main facilities and its related facilities at a high level, it is necessary to analyze the degree of disaster such as flood depth, flood flow rate, flood time and flood intensity when extreme floods (LIP) are introduced. In addition, the degree of vulnerability of these related facilities should be assessed and risk assessments should be reassessed through linkage analysis that combines the degree of disaster and vulnerability. By calculating a new flood hazard curve for the flood depth and flood intensity in major national facilities under the heavy rainfall conditions through this study, it is expected to be a basis for the waterproof design of important SOC facilities, flood prevention function design, advancement of flood prevention measures and procedures and evaluation of flood mitigation functions.