• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.115-126
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• 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.

• Journal of Korea Water Resources Association
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• v.47 no.2
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• pp.107-117
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• 2014

Hancheon reservoir, which is located upstream of Jeju city, has been built for flood mitigation after Typhoon Nari, 2007. To verify flood mitigating effect of the this reservoir on the downstream area, runoff analysis based on the measured data (two stream discharge monitoring stations and inflow data to the reservoir) is carried out during torrential rain followed by typhoon Dainmu, 2010. The stream water level was recorded as 3.14 m for the peak at the down gradient station. The stream water level under the assumption of absence of Hancheon reservoir is calculated as 4.16 m using the estimated rating curve, stream water propagation velocity, and the bypassed volume of water to the reservoir. This result shows that clear effect of reservoir operation which is capable of mitigating peak discharge in the downstream area.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.231-236
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• 2006

본 연구에서는 단일 첨두를 갖는 가상의 균일하도구간과 홍수피해가 극심하게 나타나고 있는 낙동강유역에 대하여 Saint-Venant 방정식을 음해적으로 유한차분하여 수치적으로 해석한 수리학적 하도추적을 FLDWAV 모형을 이용하여 수행함으로써 홍수파의 전달양상과 천변저류지의 홍수 저감영향을 분석하였다. 균일하도구간에 대한 적용은 천변저류지의 규모와 운영조건 그리고 설치위치에 따른 홍수 저감영향을 비교검토함으로써 천변저류지의 최적 규모 및 설치위치를 결정하는데 효과적인 참고 자료가 될 것으로 기대된다. 또한 낙동강유역에 대한 적용에서는 낙동강 하천정비 기본계획에 근거한 계획홍수량으로 모의를 수행하였다. 낙동강 유역종합 치수계획 보고서에 제시된 10개의 천변저류지에 대한 모의를 통해 실제 낙동강유역의 홍수 저감영향을 분석함으로써 하천제방 계획시 경제적인 하천 제방단면 결정을 위한 참고 자료 및 효과적인 홍수피해 경감대책 수립을 위한 기초 자료를 제시하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.815-819
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• 2007

최근 기록적인 집중호우와 태풍으로 인해 홍수의 피해가 점점 증가하고 있다. FLUMEN과 같은 홍수범람 해석 모형을 이용한 비구조적인 홍수대책들은 홍수 피해를 확실히 경감시켜줄 수 있다. 본 연구에서는 FLUMEN 모형의 적용성을 검토하여 홍수피해 저감방안을 제시하였다. 천수방정식을 지배방정식으로 하고 유한체적법에 기반을 둔 이 모형을 대상유역으로 진위천 구간을 선정하여 적용하였다. 1998년 8월 7일${\sim}$9일에 발생했던 실제 강우사상으로 적용성을 검토하였으며, 침수실적도와 모의범람면적을 비교하였을 때 미미한 차이를 보였다. 적용성 검증 후, 빈도별 홍수범람 모의를 실시하였으며, 200년 빈도의 홍수량에 대하여 2가지 경감대책(제방의 보축, 상류 유입부 천변저류지)에 대하여 범람모의 하였다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.59-62
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• 2008

Scour vulnerability evaluation for shallow foundations was performed to assure bridge safety against scour in the national capital region. The case studies for 26 shallow foundations consisted of site investigation including boring test, bridge scour analysis for the design flood, bearing capacity evaluation of the bridge foundation before and after scour, and comprehensive evaluation of bridge scour vulnerability. Bridge scour vulnerability was determined based on the interdisciplinary concept considering predicted scour depth for the design floods and bearing capacity of foundation as well as dimensions of foundation. Nine of 26 shallow foundations showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 were expected to maintain their stability against scour.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.309-312
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• 2008

In Korea, although the damage from disaster (flood and storm) is increasing, the early stage warning and countermeasure are not in operation rapidly. The research areas of transportation engineering arenot diverse, so once the road is flooded and interrupted, drivers, the system operators and managers are in panic, and nearby roads are in terrible traffic congestion. In case of Korea, the research of evacuation is highly needed, because it is very necessary and easy to apply in real field. In this paper, we establish the concept of transportation disaster prevention system and suggest the directions of it. In addition, based on this research, we choose one example of disasters and establish an example of the transportation disaster prevention system. Our goal is to make steps; prevention, preparation, countermeasure and restoration in the view of minimizing on social chaos and damages emphasizing aspect of transportation countermeasure. This research will be the good precedent of approach, analysis and countermeasure when the disasters are occurred, and a basis of transportation disaster prevention system and manual in Korea.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.77-85
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• 2009

In South Korea, seasonal, local and temporal climatic characteristics are variable in rainfall patterns. To design or assess the reliability of hydrosystem, information about the rainfall event under consideration is important. In this process, the complete description of a design storm involves the specification of rainfall duration, depth, and its temporal pattern. Generally, to use an appropriate temporal pattern for a design storm is of great importance in the design and evaluation of hydrological safety for hydrosystem. For purpose of selecting of factors affecting the occurrence of rainfall patterns, Huff's dimensionless method was executed and examined by statistical contingency tables analysis through which the inter-dependence of the occurrence frequency of rainfall patterns with respect to geographical location, rainfall duration and depth, and seasonality is investigated. This analysis result can be used to establish flood policies and to design or assess the reliability of hydrosystem.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.93-102
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• 2009

A prediction of streamflow based on multi-objective function is presented to check the performance of Probability Distributed Model(PDM) in Miho stream basin, Chungcheongbuk-do, Korea. PDM is a lumped conceptual rainfall runoff model which has been widely used for flood prevention activities in UK Environmental Agency. The Monte Carlo Analysis Toolkit(MCAT) is a numerical analysis tools based on population sampling, which allows evaluation of performance, identifiability, regional sensitivity and etc. PDM is calibrated for five model parameters by using MCAT. The results show that the performance of model parameters(cmax and k(q)) indicates high identifiability and the others obtain equifinality. In addition, the multi-objective function is applied to PDM for seeking suitable model parameters. The solution of the multi-objective function consists of the Pareto solution accounting to various trade-offs between the different objective functions considering properties of hydrograph. The result indicated the performance of model and simulated hydrograph are acceptable in terms on Nash Sutcliffe Effciency*(=0.035), FSB(=0.161), and FDBH(=0.809) to calibration periods, validation periods as well.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.125-130
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• 2009

Storage function method which considers the non-linearity of the relationship between rainfall and runoff has been frequently used to predict runoff in a basin and a flood pattern. However, it is time-consuming to estimate appropriate parameters of every basin and rainfall event, which requires the empirical parameter equation applicable in Korea. In this study, multiple regression analysis is used to develop empirical equations to estimate parameters of Storage Function method using basin characteristics. The basin area, maximum stream length, and stream slope are considered as the basin characteristics as the result of the regression analysis. Collinearity is removed and trial-and-error method is used to choose the most descriptive parameters to the dependent variables in Han River basin which is divided into 30 subbasins. The developed equations are validated using the rainfall events in MunMak gauging station and named as 'Han River equation'. The equation could provide the useful information about Storage Function method parameter to calculate runoff from a basin and predict river stage.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.723-726
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• 2008

It is not always easy to estimate the parameters in hydrologic models due to insufficient hydrologic data when hydraulic structures are designed or water resources plan are established, uncertainty analysis, therefore, are inevitably needed to examine reliability for the estimated results. With regard to this point, this study applies a Bayesian Markov Chain Monte Carlo scheme to the NWS-PC rainfall-runoff model that has been widely used, and a case study is performed in Soyang Dam watershed in Korea. The NWS-PC model is calibrated against observed daily runoff, and thirteen parameters in the model are optimized as well as posterior distributions associated with each parameter are derived. The Bayesian Markov Chain Monte Carlo shows a improved result in terms of statistical performance measures and graphical examination. The patterns of runoff can be influenced by various factors and the Bayesian approaches are capable of translating the uncertainties into parameter uncertainties. One could provide against an expected runoff event by utilizing information driven by Bayesian methods. Therefore, the rainfall-runoff analysis coupled with the uncertainty analysis can give us an insight in evaluating flood risk and dam size in a reasonable way.