• 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.

• Proceedings of the KSRS Conference
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• v.2
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• pp.884-887
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• 2006

This paper focuses on minimizing flood damage in the Yeongdeok basin of South Korea by establishing a flood prediction model based on a geographic information system (GIS), remote sensing, and geomorphoclimatic instantaneous unit hydrograph (GcIUH) techniques. The GIS database for flash flood prediction was created using data from digital elevation models (DEMs), soil maps, and Landsat satellite imagery. Flood prediction was based on the peak discharge calculated at the sub-basin scale using hydrogeomorphologic techniques and the threshold runoff value. Using the developed flash flood prediction model, rainfall conditions with the potential to cause flooding were determined based on the cumulative rainfall for 20 minutes, considering rainfall duration, peak discharge, and flooding in the Yeongdeok basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1592-1596
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• 2007

Accuracy of flood forecasting is an important non-structural measure on the flood control and mitigation. Hence, combination of horologic model with real time error correction became an important issue. It is one of the efficient ways to improve the forecasting precision. In this work, an approach based on Kalman Filter (KF) is proposed to continuously revise state estimates to promote the accuracy of flood forecasting results. The case study refers to the Wi River in Korea, with the flood forecasting results of Xinanjiang model. Compared to the results, the corrected results based on the Kalman filter are more accurate. It proved that this method can take good effect on hydrologic forecasting of Wi River, Korea, although there are also flood peak discharge and flood reach time biases. The average determined coefficient and the peak discharge are quite improved, with the determined coefficient exceeding 0.95 for every year.

• Journal of Korea Water Resources Association
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• v.49 no.7
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• pp.599-606
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• 2016

The objective of this study is to estimate the unregulated flood frequency from Chungju dam to Yangpyung gauging station for the region affected by dams based on the peak discharges simulated by storage function routing model. From the flood frequency analyses, the quantiles for the unregulated flood frequency at 6 sites have similar pattern to each other, and their averaged quantile almost matched to the result from the regional flood frequency analysis. The quantile and annual mean discharge for the unregulated flood frequency for the downstream of Chungju dam show the similar behaviour to those for the upstream area. While the quantile and the annual mean discharge for the regulated flood frequency are significantly different from those for the unregulated flood frequency. In particular, the qunatile shows severe difference as the return period increases, and the annual mean discharge has a tendency to approach to the natural flood as the distance from dam increases.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.145-154
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• 2004

The purpose of this study is to develop a real-time forecasting model in order to predict the flood runoff which has the nature of non-linearity and to verify applicability of neural network model for flood warning system. Developed model based on neural network, NRDFM(Neural River Discharge-Stage Forecasting Model) is applied to predict the flood discharge on Waekwann and Jindong stations in Nakdong river basin. As a result of flood forecasting on these two stations, it can be concluded that NRDFM-II is the best predictive model for real-time operation. In addition, the results of forecasting used on NRDFM-I and NRDFM-II model are not bad and these models showed sufficient probability for real-time flood forecasting. Consequently, it is expected that NRDFM in this study can be utilized as suitable model for real-time flood warning system and this model can perform flood control and management efficiently.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1033-1039
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• 2018

In Korea, every year during the summer season, typhoons and torrential rains cause floods and damage to property. In particular, the Imjin River basin is characterized by steep slopes, narrow upstream areas, and low flat downstream areas, which are vulnerable to floods. In addition, damages occurred due to unauthorized discharge in the Hwanggang Dam, a large dam upstream of the Imjin River in North Korea. In order to prevent such flood damage, Korea is constructing the Gunnam Flood Control Site in 2010 to prevent flood damage. However, even after the construction of the flood control zone, the flood control capacity is only 20% of the maximum water level of the Hwanggang dam. This study used LAHARZ_py program to calculate flood damage area in the northern part of Gyeonggi province. As a result, when the discharge of Hwanggang dam exceeding the flood control ability of Gunnam flood control zone occurs, damage to Yeoncheon-gun and Paju-si of Gyeonggi-do was expected. This study will be useful as a material to prepare for flood damage.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1079-1088
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• 2013

The objective of this paper is compare to landuse type for calculating peak flood and soil loss in rapidly expansion urban area. This study compares two landuse maps, including numerical landuse map and aerial photograph landuse map, for calculating the ratio of urban and agriculural area, curve number, time of concentration, peak flood discharge, and soil loss. It is found that flood discharge calculated using aerial photograph landuse map are larger than that calculated using numerical landuse map, and soil loss calculated using aerial photograph landuse map are smaller than that calculated using numerical landuse map. Results also indicate that landuse chage in rapidly expansion urban area significantly influences flood discharge and soil loss.

• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.333-343
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• 2022

For water resource management, the design flood is calculated using the flood frequency analysis technique and the rainfall runoff model. The method by design flood frequency analysis calculates the stochastic design flood by directly analyzing the actual discharge data and is theoretically evaluated as the most accurate method. Actual discharge data frequency analysis of the measured flow was limited due to data limitations in the existing flood flow analysis. In this study, design flood frequency analysis was performed using the measured flow data stably secured through the water level-discharge relationship curve formula. For the frequency analysis of design flood, the parameters were calculated by applying the bayesian inference, and the uncertainty of flood volume by frequency was quantified. It was confirmed that the result of calculating the design flood was close to that calculated by the rainfall-runoff model by applying long-term rainfall data. It is judged that hydrological analysis can be done from various perspectives by using long-term actual flow data through hydrological survey.

• Water for future
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• v.26 no.1
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• pp.93-101
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• 1993

Because of the Keumkangsan-Dam and the Peace-Dam constructed in recent years, it is expected that the peak flood discharge and the peak flood stage at the Hwachun-Dam site have been changed. In this study, two methods were used to simulate and compare the effects of the upstream dam construction on the change of the discharge and the stage. One is the storage function method widely used for the hydrological routing in this country. The other is the DWOPER (Dynamic Wave Operational Model) package developed by the U.S. NWS for the hydraulic routing. Flood routing simulations have been performed on four different scenarios:1) Before the construction of the Keumkangsan-Dam and the peace-Dam, 2) The exclusion of the Keumkangsan-Dam watershed (before the construction of the Peace-Dam), 3) The exclusion of the Keumkangsan-Dam watershed (after the construction of the Peace-Dam), 4) The exclusion of the Peace-Dam watershed. The results of the four test cases from the two methods show that the peak flood discharge and the peak flood stage at the Hwachun-Dam site are reduced due to the construction of the Peace-Dam. From these findings, it is suggested that the operational criteria for the optimal dam-operation of the hwachun-Dam need to be modified.

• Korean Journal of Remote Sensing
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• v.35 no.5_2
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• pp.781-796
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• 2019

This study attempted to simulate the flood discharge in the Duman River basin containing Hoeryong City and Musan County of North Korea where were damaged from Typhoon Lionrock on August, 2016. For hydrological modelling remotely sensed datasets were used to estimate watershed properties and hydrologic factors because the basin is ungauged where hydrological observation is not exist or sparse. For validation we applied our methodology and datasets to the Soyanggang Dam basin. It has not only similar shape factor and compactness ratio to those of the target basin but also accurate, adequate, and abundant measurements. The results showed that the flood discharge from Typhoon Lionrock corresponded to three to five years design floods in the Duman River basin. This indicate that the Duman River basin has a high risk of flood in the near future. Finally this study demonstrated that remotely sensed data and geographic information could be utilized to simulate flood discharge in an ungauged watershed.