• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.957-964
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• 2013

This research is on the methodology of flood risk assessment using flooding characteristic values. Necessity of design magnitude for flood control considering floods was judged by plotting peak flow with respect to frequency and duration, and flooding magnitude was defined with 6 flooding characteristic values which were proposed to be significant factors when assessing flooding magnitude. Precipitation data used in the assessment modeling were applied by combining all the possible precipitation events. After overlapping the simulated results with precipitation matrix by flooding characteristic values, contour map was drawn, and Flooding characteristic contour graph for possible rainfall events were suggested in respect of all possible precipitation. Flooding characteristic contour graph for possible rainfall events was confirmed that reducing of damage magnitude of each flood characteristic value was figured out easily. The flood risk assessment methods suggested in this study would be a good reference for urban drainage system design, which only focuses on pipe conduit.

• Korean Journal of Hydrosciences
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• v.4
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• pp.11-19
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• 1993

The peak flood discharge at a downstream station and the flood travel time between a pair of dams due to a specific flood release from the upper reservoir are computed using a hydraulic river channel routing method. The study covered the whole large reservoir system in the Han River, Korea. The computed flood discharges and the travel times between dams were correlated with the duration and the magnitude of flood release rate at the upstream reservoir, and hence a multiple regression model is proposed for each river reach between a pair of dams. The peak flood discharge at a downstream location can be converted to the peak flood stage by a rating curve. Hence, the proposed regression model could be used to forecast the peak flood stage at a downstream location and the flood travel time between dams using the information on the flood travel time, release rate and duration from the upper dam.

• Journal of Korea Water Resources Association
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• v.38 no.2
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• pp.121-131
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• 2005

In this study, a flood routing model is used for analyzing change of flood stage induced by various factors. The results by using the past cross section measurement data showed the minimum error in case of accurate measurement of cross section as well as reasonable boundary condition of model. In analyzing the rise of flood stage of main stream considering Inflow magnitude of tributary, it showed that the larger the flow magnitude is, the smaller the variance of stage is. The results of analysis in the tidal effect at Wolgot are that the tidal effect influence the stage profile into upstream in case of normal discharge of main stream and tributary but doesn't influence it even with maximum flood tide in case of project flood. Finally, when the various hydraulic factors are considered in numerical analysis, more systematic and realistic flood forecast system is able to be performed.

• Journal of Korea Water Resources Association
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• v.45 no.10
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• pp.1035-1041
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• 2012

This paper is on the decision of design magnitude for flood control of urban basin, based on flooding characteristic values. In Korea, a design magnitude for flood control is established based on peak discharge of the outlet of basin. However, this method is inappropriate in an urban basin because sewerage only can flow out as much as it could and other discharge overflow to basin. In order to calculate a design magnitude for flood control of an urban basin, flooding characteristic values (peak discharge of pipe, average flooded depth, maximum flooded depths of an important point, flooded area, flooded volume, flooded time) were used as a tool. Using the Gwanghwamun Square as an example, a methodology was proposed that used XP-SWMM 2010 model as a platform to predict urban flood disaster. It can help other local government and residents to better understand, prepare for and manage a flood in urban environments.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.410-413
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• 2008

We constructed the regional flood risk and damage magnitude using hazard and vulnerabilities which are climatic, hydrological, socio-economic, countermeasure, disaster probability components for DB construction on the GIS system. Also we developed the Excess Flood Vulnerability index estimation System(EFVS). By the construction of the System, we can perform the scientific flood management for the flood prevention and optional extreme flood defenses according to regional characteristics. In order to evaluate the performance of system, we applied EFVS to Anseong-chen in Korea, and the system's stabilization is appropriate to flood damage analysis.

• Water Engineering Research
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• v.1 no.1
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• pp.49-61
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• 2000

Magnitude-frequency relationships are used in the design of dams, highway bridges, culverts, water supply systems, and flood control structures. In this paper, possible techniques for analyzing flood frequency at a site are presented. A currently used approach to flood frequency analysis is based on the concept of parametric statistical inference. In this analysis, the assumption is make that the distribution function describing flood data in known. However, such an assumption is not always justified. Even though many people have shown that the nonparametric method provides a better fit to the data than the parometric method and gives more reliable flood estimates. the noparpmetric method implies a small probability in extrapolation beyond the highest observed data in the sample. Therefore, a remedy is presented in this paper by introducing an estimator which mixes parametric and nonparametric density estimate.

• Water for future
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• v.25 no.3
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• pp.115-124
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• 1992

The peak flood discharge at a downstream station and the flood travel time between a pair of dams due to a specific flood release from the upper reservoir are computed using a hydraulic river channel routing method. The study covered the whole reservoir system in the Han River. The computed peak flood discharges and the travel times between dams were correlated with the duration and the magnitude of flood release rate at the upstream reservoir, and hence a multiple regression model is proposed for each river reach between a pair of dams. The peak flood discharge at a downstream location can be converted to the peak flood stage by rating curve. Hence, the proposed regression model could be used to forecast the peak flood stage at a downstream location and the flood travel time between dams using the information on the flood release rate and duration from the upper dam.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.4
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• pp.81-88
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• 1990

The flow in a river reach where is influenced by tidal motion is characterized by unsteady flow. The flood analysis in the river reach needs depending upon the theory based on the complete unsteady flow equations. In this study the unsteady flow model which is called CRIUM (Channel Routing by Implicit Unsteady Flow Model) was developed and was applied to the Mankyong and Dongjin river in order to analyze the flood characteristics. The results, which were calibrated and verified by the flood records to be measured in the two rivers, show that unsteady flow mode] can be used for the derivation of the flood hydrograph. The peak flood discharges were estimated as 4,960 and $2,870m^3$/sec in 100 year frequency at the estuary of the Mankyong and Dongjin river, respectively. In addition, it was analyzed that the river reaches were not influenced by tidal motion when the discharge magnitude was larger than approximately $3,000m^3$/sec.

• The Korean Journal of Quaternary Research
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• v.5 no.1
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• pp.33-45
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• 1991

Sand bars associated with strong tidal currents are well developed in the subtidal zone near the Kokunsan islands. Tidal currents measured at sand bar in the area show an asymmetry in magnitude between flood and ebb currents. At the southern flank of the sand bar the currents are flood-dominant whereas the currents are ebb-dominant at the northern flank. The asymmetry is more distinctive as the currents become stronger during spring tide. Moreover, the flood-dominance along the southern flank is stronger than the ebb-dominance along the northern flank. Thus the flood current is more affective to the sand bar. The sandy bottom sediment is mostly transported as bedload by the tidal currents. The magnitude asymmetry of the tidal currents results in a net sediment movement in one direction. The direction is onshore in the south and offshore in the north, which may result in a net counterlookwise rotation of the sands around the sand bar. However, the sand bar may migrate towards onshore due to the more affective flood current in the south. The irregular V-shaped outline of the sand bar in the south also seem to reflect the strong effect of flood current.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.62-71
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• 2004

There are 109 A class rivers in Japan. One purpose of river management is to reduce the flooding. For this purpose, government provides the information to public, as flood forecasting, rainfall forecasting and estimate the runoff magnitude to avoid the flood and inundation. In this paper, we introduce current situation of flood forecasting and rainfall forecasting in Japan, and we describe how to use the information of flood forecasting and rainfall forecasting in conjunction with current strategy for river management.