• Journal of Environmental Science International
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• v.24 no.8
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• pp.1023-1036
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• 2015

A reliable streamflow forecasting is essential for flood disaster prevention, reservoir operation, water supply and water resources management. This study proposes a hybrid model for river stage forecasting and investigates its accuracy. The proposed model is the wavelet packet-based artificial neural network(WPANN). Wavelet packet transform(WPT) module in WPANN model is employed to decompose an input time series into approximation and detail components. The decomposed time series are then used as inputs of artificial neural network(ANN) module in WPANN model. Based on model performance indexes, WPANN models are found to produce better efficiency than ANN model. WPANN-sym10 model yields the best performance among all other models. It is found that WPT improves the accuracy of ANN model. The results obtained from this study indicate that the conjunction of WPT and ANN can improve the efficiency of ANN model and can be a potential tool for forecasting river stage more accurately.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.196-196
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• 2016

Landslide dam failure presents as a severe natural disaster due to its adverse impact to people and property. If the landslide dams failed, the discharge of a huge volume of both water and sediment could result in a catastrophic flood in the downstream area. In most of previous studies, breaching process used to be considered as a constructed dam, rather than as a landslide dam. Their erosion rate was assumed to relate to discharge by a sediment transport equation. However, during surface erosion of landslide dam, the sediment transportation regime is greatly dependent on the slope surface and the sediment concentration in the flow. This study aims to accurately simulate the outflow hydrograph caused by landslide dam by overtopping through a 2D surface flow erosion/deposition model. The lateral erosion velocity in this model was presented as a function of the shear stress on the side wall. The simulated results were then compared and it was coherent with the results obtained from the experiments.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.338-338
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• 2021

우리나라 최남단에 위치한 광역자치단체인 제주특별자치도는 태풍의 길목에 위치한 지정학적 특성, 한라산 영향에 의한 호우의 산지효과, 기후변화로 인한 해수면상승 가속화 등에 의해 재해 위험이 매우 높은 지역이다. 또한, 연안지역에 위치한 주거지, 숙박시설 입지 특성과 더불어 해안가의 개발수요 증가에 따라 재해취약성도 지속적으로 악화되고 있다. 이에 본 연구에서는 제주지역을 대상으로 침수재해 취약성을 평가하고, 취약지역 특성을 파악한다. 그 결과, 도 내의 취약지역 분포와 취약등급에 따른 지역적 특성을 알 수 있었으며, 이를 토대로 취약지역 여건에 맞는 도시계획적 방재대책에 대한 시사점을 확인할 수 있었다. 이상과 같은 결과는 기후변화 심화로 인한 호우 패턴 변화에 대응하기 위해 전방위적인 방재시설이 필요함은 물론, 취약지역에 적합한 도시계획적 관점의 관리대책이 마련되어야 함을 시사한다.

• Annual Conference of KIPS
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• 2022.11a
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• pp.311-313
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• 2022

홍수재난 예방 서비스 및 수질 모니터링에 대한 연구개발이 미흡하다는 문제점을 발견했다. 실생활에서 간편하게 댐의 수질·수위를 관리할 수 있는 시스템 연구를 진행했다. 이는 사용자가 수질 변화에 빠른 대응을 할 수 있을 것이다. 또한, 홍수로 인한 물적·인적자원 손실을 최소화하고, 홍수에 대한 경각심을 높이는 시너지 효과도 거둘 수 있을 것이다.

• Annual Conference of KIPS
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• 2022.11a
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• pp.100-101
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• 2022

본 논문에서는 폭우로 인한 피해를 줄이기 위해 공공데이터의 대피소 현황과 과거 침수, 범람 정보를 토대로 재난상황 발생시 시민들이 실시간으로 대비할 수 있는 재난대피소 시각화 시스템을 설계한다. 설계된 재난대피소 시각화 시스템은 인접한 대피소 안내, 과거 침수, 범람 구역 시각화, 예상 침수, 범람 구역 시각화 기능으로 구성되어 있다. 본 시스템을 통하여 시각화 된 예상 침수 구역을 기반으로 수방 시설 대비와 침수로 인한 피해를 최소화할 수 있을 것이다.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.519-528
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• 2016

Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.

• Journal of Korea Water Resources Association
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• v.45 no.10
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• pp.1023-1034
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• 2012

Linear regression technique has been used widely in water resources field as well as various fields such as economics and statistics, and so on. Using fuzzy regression technique, it is possible to quantify uncertainty and reflect them to the regression model. In this study, fuzzy regression model is developed to compute design floods in any place in Pyeongchang River basin. In ungaged basins, it is usually difficult to obtain data required for flood discharge analysis. In this study, basin characteristics elements are analyzed spatially using GIS and the technique of estimating design flood in ungaged mountainous basin is studied based on the result. Fuzzy regression technique is applied to Pyeongchang River basin which has mountainous basin characteristics and well collected rainfall and runoff data through IHP test basin project. Fuzzy design flood estimation equations are developed using the basin characteristics elements for Pyeongchang River basin. The suitability of developed fuzzy equations are examined by comparing the results with design floods computed in 9 locations along the river. Using regional regression method and fuzzy regression analysis, the uncertainties of the design floods occurred from the data monitoring can be quantified.

• Journal of Environmental Policy
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• v.5 no.4
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• pp.1-18
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• 2006

Recently, the damage by fresh flood increases in Gangwon-do and Gyeongsangbuk-do of the north-eastern area of Korea. Even though the recent pattern of rain fall keeps changing, there is no strategy to mitigate damage by disaster. For the appropriate measure and policy for decreasing damage, an index for vulnerability is necessary to provide evidence of local climate change. The present work analyzes the flooding damage cost during the past 20 years. During 80's, the southern area of Korea was seriously damaged by over-floods on the agricultural ground. After that time, the loss and damage has decreased in the southern area but the middle part has shown slight but distinct increases of damage. The absolute coast of damage in the northern part has kept constant. However, the relative regional damage to the total country damage has kept increasing over 20 years in the same area. The surface area of floods is strongly correlated with the regional damage cost in the southern part but the north-eastern part has weak correlation between flooded area and cost. It implies that the recent damage in the north-eastern mountain area was not caused by flood itself but the other factors such as avalanches. The present work expects that the damage cost can be a good proxy value for index for climate change impact assessment.

• Journal of Korea Water Resources Association
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• v.37 no.9
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• pp.707-718
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• 2004

This study is to analyze the Probable Maximum Flood(PMF) as a part of counterplan for the disaster prevention of hydraulic structures such as dams, according to recent unfavorable weather conditions. During the period of typhoon RUSA in August 2002, the rainfall recorded in Gang-loeng Province was 880mm a day and exceeded the scale of PMP made in 2001. Accordingly, the reconsideration of hydrologic criteria for dam design was inevitable. In the design of dams for flood controls, the design flood must be determined by introducing the concept of maximum values. When the duration of design rainfall is determined, it needs to use the critical duration which causes the maximum flood by the maximum runoff. In this study, we Investigate the variation of critical duration with hydrologic parameters used in three different synthetic unit hydrographs(Clark, Nakayasu and SCS methods). As a result, the total runoff calculated from 24-hour duration is larger than that calculated from the critical duration. We calculate also the hydrographs with three different time distribution models(Huff's 4-quartile, IDF curve and Mononobe) and compare those with measured hydrograph data. From this comparison, we propose that the Huff's 4-quartile model must be used to obtain the desirable data in the hydrologic design of dams.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.30-30
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• 2023

This study aims to establish the multi-reservoir operation system model in the Upper Mun River Basin which includes 5 main dams namely, Mun Bon (MB), Lamchae (LC), Lam Takhong (LTK), Lam Phraphoeng (LPP), and Lower Lam Chiengkrai (LLCK) Dams. The knowledge and AI technology were applied aiming to develop innovative prototype for SMART dam-reservoir operation in future. Two different sorts of reservoir operation system model namely, Fuzzy Logic (FL) and Constraint Programming (CP) as well as the development of rainfall and reservoir inflow prediction models using Machine Learning (ML) technique were made to help specify the right amount of daily reservoir releases for the Royal Irrigation Department (RID). The model could also provide the essential information particularly for the Office of National Water Resource of Thailand (ONWR) to determine the short-term and long-term water resource management plan and strengthen water security against flood and drought in this region. The simulated results of base case scenario for reservoir operation in the Upper Mun from 2008 to 2021 indicated that in the same circumstances, FL and CP models could specify the new release schemes to increase the reservoir water storages at the beginning of dry season of approximately 125.25 and 142.20 MCM per year. This means that supplying the agricultural water to farmers in dry season could be well managed. In other words, water scarcity problem could substantially be moderated at some extent in case of incapability to control the expansion of cultivated area size properly. Moreover, using AI technology to determine the new reservoir release schemes plays important role in reducing the actual volume of water shortfall in the basin although the drought situation at LTK and LLCK Dams were still existed in some periods of time. Meanwhile, considering the predicted inflow and hydrologic factors downstream of 5 main dams by FL model and minimizing the flood volume by CP model could ensure that flood risk was considerably minimized as a result of new release schemes.