• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2460-2468
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• 2014

A local rain that is concentrated in specific area in a short time frequently occurs due to recent abnormal weather. To prevent potential flood disasters, therefore, it is necessary to be established to the flood control system. Checking the river design standard, however, hydrologic design frequency of water gate is only marked as over 20 years, so this fact shows that the standard is unclear. The inland inundation modeling considering the stage in a river and quantitative assessment are required to reduce flood damage. The simulation for internal inundation is very complex and is time-consuming due to considering hydraulic hydrology characteristics at the same time. Using the already established river master plan, consequently, this study proposed the simple and convenient method for assessment of the internal inundation simulation. Using the proposed method in the upper and middle regions of a river, influences for design frequency or water gate location were assessed by applying the nine probability precipitation with design frequency and by targeting the water gates which are installed in five inlands.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.270-278
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• 2010

Applicability of the MIKE21 model as a real time coupled tide-surge model had been examined at the previous study. In this study, another applicability of the model as an inundation model is also examined. Prior to real cases, effect of artificial structures on the inundation is analyzed. The results show that inundation depth is not altered, while inundation area is lessened as a result of decreased inundation speed. Comparative study between the coupled model and an uncoupled storm surge model is also carried out at the Masan coastal zone, which shows the coupled model is considered to be plausible at the time to maximum inundation, while both models show similar results at the inundation area and inundation depth.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.33-43
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• 2020

In order to reduce damage from farmland inundation caused by recent climate change, it is necessary to predict the risk of farmland inundation accurately. Inundation modeling should be performed by considering multiple time distributions of possible rainfalls, as digital forecasts of Korea Meteorological Administration is provided on a six-hour basis. As building multiple inputs and creating inundation models take a lot of time, it is necessary to shorten the forecast time by building a data base (DB) of farmland inundation probability. Therefore, the objective of this study is to establish a DB of farmland inundation probability in accordance with forecasted rainfalls. In this study, historical data of the digital forecasts was collected and used for time division. Inundation modeling was performed 100 times for each rainfall event. Time disaggregation of forecasted rainfall was performed by applying the Multiplicative Random Cascade (MRC) model, which uses consistency of fractal characteristics to six-hour rainfall data. To analyze the inundation of farmland, the river level was simulated using the Hydrologic Engineering Center - River Analysis System (HEC-RAS). The level of farmland was calculated by applying a simulation technique based on the water balance equation. The inundation probability was calculated by extracting the number of inundation occurrences out of the total number of simulations, and the results were stored in the DB of farmland inundation probability. The results of this study can be used to quickly predict the risk of farmland inundation, and to prepare measures to reduce damage from inundation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1192-1200
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• 2007

A general rainfall outflow in urban drainage has early time of concentration because urban drainage areas are most paved area. In general, rainfall outflow is flowed in drainage pump station and is discharged to rivers in urban areas. However it is excluded through drainage pumps about a heavy rainfall which exceed the design rainfall and the rainfall outflows increase the urban inundation risk. A current pump operation is control according to water level of collecting well or reservoir in drain pump station. But recently, the localized downpours are happened frequently in urban drainage and the current pump stations are frequently incapable of the heavy rainfall outflows. In this study, a real urban inundation was simulated and the drain capacity of drain pump station was evaluated by analysis about flood-factor in urban underground passage. Then the analysis about the inundation was done by the simulation about the real rainfall which cause the inundation. Also, in the simulation the inundation risk and the evaluation of flood-factor were analyzed according to change of the pump operation rule.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.68-75
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• 2010

Recently, the intensity and frequency of typhoons have been on the increase due to unusual weather phenomena and climate change. In particular, on September 13, 2003, typhoon MAEMI (0314) caused heavy damage in the provinces of Busan and Gyongnam, but also provided an opportunity to perform a variety of studies on storm surge. According to investigation reports on the damage resulting from typhoon MAEMI, the areas where coastal inundation occurred were located in reclaimed land under coastal development. In this study, through an image data analysis of historic and present day typhoons affecting Masan, we found that the inundation damage areas corresponded to reclaimed lands. Therefore, using the area around Busan, including the southeastern coast of Korea where typhoons lead to an increased storm surge risk, we performed a storm surge/inundation simulation, and examined the inundation effect on reclaimed land due to the intensified typhoons predicted for the future by climate change scenarios.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.396-396
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• 2015

Frequent urban floods affect the human safety and economic properties due to a lack of the capacity of drainage system and the increased frequency of torrential rainfall. The drainage system has played an important role in flooding control, so it is necessary to establish the effective countermeasures considering the connection between drainage system and surface flow. To consider the connection, we selected SWMM5 model for analyzing transportation capacity of drainage system and FLUMEN model for calculating inundation depth and time variation of inundation area. First, Thiessen method is used to delineate the sub-catchments effectively base on drainage network data in SWMM5. Then, the output data of SWMM5, hydrograph of each manhole, were used to simulate FLUMEN to obtain inundation depth and time variation of inundation area. The proposed method is applied to Sadang area for the event occurred in $27^{th}$ of July, 2011. A total of 11 manholes, we could check the overflow from the manholes during that event as a result of the SWMM5 simulation. After that, FLUMEN was utilized to simulate overland flow using the overflow discharge to calculate inundation depth and area on ground surface. The simulated results showed reasonable agreements with observed data. Through the simulations, we confirmed that the main reason of the inundation was the insufficient transportation capacities of drainage system. Therefore cooperation of both models can be used for not only estimating inundation damages in urban areas but also for providing the theoretical supports of the urban network reconstruction. As a future works, it is recommended to decide optimized pipe diameters for efficient urban inundation simulations.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.4
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• pp.25-32
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• 2023

KDS (Korean Design Standard) for agricultural drainage is a planning standard that helps determine the appropriate capacity and type of drainage facilities. The objective of this study was to analyze the inundation of the agricultural basin considering the current design standard and the critical rainfall duration. This study used the rainfall durations of 1-48 hour, and the time distribution method with the Chicago and the modified Huff model. For the runoff model, the NRCS (Natural Resources Conservation Service) unit hydrograph method was applied, and the inundation depth and duration were analyzed using area-elevation data. From the inundation analysis using the modified Huff method with different rainfall durations, 4 hours showed the largest peak discharge, and 11 hours showed the largest inundation depth. From the comparison analysis with the current method (Chicago method with a duration of 48 hours) and the modified Huff method applying critical rainfall duration, the current method showed less peak discharge and lower inundation depth compared to the modified Huff method. From the simulation of changing values of drainage rate, the duration of 11 hours showed larger inundation depth and duration compared to the duration of 4 hours. Accordingly, the modified Huff method with the critical rainfall duration would likely be a safer design than the current method. Also, a process of choosing a design hydrograph considering the inundation depth and duration is needed to apply the critical rainfall duration. This study is expected to be helpful for the theoretical basis of the agricultural drainage design standards.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.115-122
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• 2020

Due to the climate change, torrential rain downpours unprecedentedly, and urban areas repeatedly suffer from the inundation damages, which cause miserable loss of property and life by flooding. Two major reasons of urban flooding are river inundation and inland submergence. However, most of previous studies ignored the comprehensive mechanism of those two factors, and showed discrepancy and inadequacy due to the linear summation of each analysis result. In this study, river inundation and inland flooding were analyzed at the same time. Petrov-stabilizing scheme was adopted to capture the shock wave accurately by which river inundation can be modularized. In addition, flux-blocking alrotithm was introduced to handle the wet and dry phenomena. Sink/source terms with EGR (Exponentially Growth Rate) concept were incorporated to the shallow water equations to consider inland flooding. Comprehensive simulation implementing inland flooding and river inundation at the same time produced satisfactory results because it can reflect the counterbalancing and superposition effects, which provided accurate prediction in flooding analysis.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.34-39
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• 2008

The aim of this study is to investigate the inundation characteristics over coastal area due to the variation of sea level and plane arrangement of manholes using the 3D numerical model that is able to simulate directly interaction of WAve Structure Sandy beach(LES-WASS-3D). At first, The adopted model was validated through the comparison with an existing experimental data and showed fairly nice agreement. And then, the inundation characteristics over coastal area are discussed in relation to the variation of sea level and plane arrangement of manholes.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.179-179
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• 2015

Citarum River is one of the important river in West Java, Indonesia. During the rainy season, flood happens almost every year in Upper Citarum Watershed, hence, it is necessary to establish the countermeasure in order to prevent and mitigate flood damages. Since the lack of hydrological data for the modelling is common problem in this area, it is difficult to prepare the countermeasures. Therefore, we used Rainfall-Runoff-Inundation (RRI) Model developed by Sayama et al. (2010) as the hydrological and inundation modelling for evaluating the inundation case happened in Upper Citarum Watershed, West Java, Indonesia and the satellite based information such as rainfall (GSMaP), landuse and so on instead of the limited hydrological data. In addition, 3 arc-second HydroSHEDS Digital Elevation Model (DEM) is used. To verify the model, the observed data of Nanjung water stage gauging station and the daily observation data are used. Simulated inundation areas are compared with the flood extent figure from Upper Citarum Basin Flood Management Project (UCBFM).