• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.194-194
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• 2017

Flooding is one of the most serious and frequently occurred natural disaster at many regions around the world. Especially, under the climate change impact, it is more and more increasingly trend. To reduce the flood damage, flood forecast and its accuracy analysis are required. This study is conducted to analyze the accuracy of the real-time flood forecasting of a coupled meteo-hydrological model for the Han River basin, South Korea. The LDAPS (Local Data Assimilation and Prediction System) products with the spatial resolution of 1.5km and lead time of 36 hours are extracted and used as inputs for the SURR (Sejong University Rainfall-Runoff) model. Three statistical criteria consisting of CC (Corelation Coefficient), RMSE (Root Mean Square Error) and ME (Model Efficiency) are used to evaluate the performance of this couple. The results are expected that the accuracy of the flood forecasting reduces following the increase of lead time corresponding to the accuracy reduction of LDAPS rainfall. Further study is planed to improve the accuracy of the real-time flood forecasting.

• Korean Journal of Environment and Ecology
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• v.9 no.1
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• pp.42-48
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• 1995

Freshwater fish fauna in Pyongchangang in which having been constructed to water supply for Chechon city was carried out to clarify the impacts of ecosystem on freshwater fish as rapid reduction of constant river flood both Sep. 25, 1994 and Oct. 7, 1994 ~ Oct. 9, 1994. It was 28 species of 21 genera on 6 Families freshwater fishes including a natural monument at and many endemic species among 6 survey stations in Pyongchang. The Pyongchang that was moved in a zigzag direction having been keep constant flood and high diversity of freshwater fishes. There was a high possibility of serious extinction on freshwater fishes as rapid reduction of constant flood in Pyongchangkang.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.165-174
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• 2011

The purpose of this research is to develop the model for analyzing the hydraulic behavior of off-stream reservoir whose purpose is to reduce a peak flood. When a flood occurs in river, off-stream reservoir has a capability of sharing a part of peak flood. It is accomplished by flowing over a off-line weir that is built by lowering a portion of bank and connecting river with off-line reservoir. Since flood control depends on river elevation, characteristics of off-line weir (elevation, length, position et al.) and reservoir capacities, an integrated model linking the one dimensional unsteady river flow model, off-line weir model and two dimensional unsteady flood model is developed to analyze the behavior of off-stream reservoir and off-line weir. The results show that a flood control capability of off-stream reservoir strongly depends on facilities of off-line weir and storage capacity of offstream reservoir.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.301-310
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• 2006

Typically, we needs enormous national budget for the flood control project and so the project usually has big influence on the national economy. Therefore, the reliable estimation of flood damage is the key issue for the economic analysis of the flood control project. This study aims to provide a GIS based technique for distributed flood damage estimation. We consider two aspects of engineering and economic sides, which are the inundation analysis and MD-FDA (Multi-Dimensional Flood Damage Analysis), for the flood damage assessment. We propose the analysis framework and data processing using GIS for assessing flood damages. The proposed methodology is applied to the flood control channel project for flood disaster prevention in Mokgamcheon/Dorimcheon streams and this study presents the detailed GIS database and the assessment results of flood damages. This study may have the worth in improving practical usability of MD-FDA and also providing research direction for combining economic side with the engineering aspect. Also this distributed technique will help decision-making in evaluating the feasibility of flood damage reduction programs for structural and nonstructural measures.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.379-385
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• 2023

EDue to climate change and urbanization, the localized heavy rainfall frequently exceeded a design storm rainfall and flood damage has occurred in South Korea. The concept of addressing sustainable river management and environmental and social issues through Nature-based Solutions (NbS) is gaining attention as it seeks to resolve these issues through ecosystem services. Therefore, in this study, the flood reduction effect by river management using NbS was quantitatively analyzed for the Hwang River, which is directly downstream of Hapcheon Dam, South Korea. Floodplain excavation and dyke relocation, which are methods of the NbS, were applied to the flood risk area of the Hwang River. As a result of analyzing the flood level of the river through the unsteady flow analysis of HEC-RAS, we obtained flood level reduction by 8 cm at the confluence of the Nakdong River. The results of this study can be expected to be sufficiently utilized as a basis for use as a management plan through NbS rather than the river management with grey infrastructure.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.81-90
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• 2017

Recent floodplain data are important for river master plan, storm and flood damage reduction comprehensive plan and pre-disaster impact assessment. Hazard map, base of floodplain data, is being emphasized as important method of non-structural flood prevention and consist of inundation trace map, inundation expected map and hazard information map. Inundation trace map describes distribution of area that damaged from typhoons, heavy rain and tsunamis and includes identified flood level, flood depth and flood time from flooding area. However due to lack of these data by local government, which are foundational and supposed to be well prepared nationwide, having hard time for making inundation trace map or hazard information map. To overcome this problem, time consumption and budget reduction is required through various research. From this study, DEM (Digital Elevation Model) from image material from UAVS (Unmanned Aerial Vehicle System) and numeric geographic map from National Geographic Information Institute are used for calculating flooding damaged area and compared with inundation trace map. As results, inundation trace map DEM based on image material from UAVS had better accuracy than that used DEM based on numeric geographic map. And making hazard map could be easier and more accurate by utilizing image material from UAVS than before.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.81-86
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• 2023

In this study, a one-dimensional numerical model was constructed to propose a flood control plan linked with the dam and river basin for the flood events of the Seomjin River in 2020. The flood level reduction of the downstream river was tested based on a scenario operation of the Seomjingang Dam and was also analyzed when a storage pocket was newly constructed as one of the river basin measures. It was confirmed that Seomjingang Dam's flood control capacity would be increased if the flood limit level was drastically lowered from the current EL. 196.5 m to EL. 188.0 m. In addition, if the upper area of the (old) Geumgok Bridge (which suffered great damage due to the loss of the levee) is used as a storage pocket, it would be effective in preventing floods in the lower area of it. In the era of the climate crisis, more integrated flood management is needed and basic river management must be observed.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.30-37
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• 2023

This study aimed to evaluate the ability to reduce flood damage caused by abnormal rainfall events due to climate change by utilizing a blue-green roof (BGF), a type of rooftop greening technology. For two buildings with the same roof area, a BGF was installed in the experimental group, a general roof was configured in the control group, and rainfall runoff was compared. A total of 10 rainfall events were tested and analyzed by classifying them into three rainfall classes (less than 10 mm, less than 100 mm, and more than 100 mm). There was a reduction of 100% in the case of 10 mm or less of rainfall, 84. 7% in the case of 100 mm or less, and 39.8% in the case of 100 mm or more. Although this study showed that a BGF was effective in reducing rainfall runoff, additional experiments and analyses of various factors affecting rainfall runoff reduction are needed to generalize the results of the study. This research methodology may be used to develop a method for evaluating the resilience of a BGF to flood damage due to climate change.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.721-733
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• 2023

As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.111-122
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• 2009

In this study, flood stage was computed by HEC-RAS, 1-D numerical analysis model and FESWMS-2DH, 2-D numerical model. Flood stages computed by two different models were compared for straight line, dot axle watercourse, dead-zone watercourse, section sudden-changing watercourse, and curved watercourse. From the results, flow velocity and water level were similar in straight watercourse and dot-reduction watercourse. However, there was difference of flow velocity and water level in dead-zone watercourse, sudden expansion, dot-reduction, and curve-watercourse. This result might be influenced by rapid change of watercourse due to dead-zone, the angle of inflow and outflow, and the curvature. Especially in this study, numerical model was applied to Wol-Song-Cheon at Chuncheon in order to analyze the effect of flood stage by two different models. By flowing properties around the bridge and confluence of rivers, it was found that flow velocity and water level was changed. Therefore, it was concluded that a lot of uncertainties are contained in the present bank.