• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.637-640
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• 2008

Flood control and river improvement works are carried out every year for the defense of the flood disaster, it is impossible to avoid the damage when there is a flood exceeding the capacity of hydraulic structures. Therefore, nonstructural counter plans such as the establishment of flood hazard maps, the flood warning systems are essential with structural counter plans. In this study, analysis of the internal inundation effect using rainfall runoff model such as PC-SWMM was applied to Woo Ee experimental stream basin. Also, the design frequency analysis for effects of the external inundation was accomplished by main parameter estimation for conclusive hydraulic routing using HEC-RAS model. Finally, inundated areas for flood hazard map were estimated at Woo Ee downstream basin according to flood frequency using HEC-GeoRAS model linked by Arc View GIS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.5
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• pp.683-694
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• 2024

Flood control capacity enhancement measures in watersheds can be broadly categorized into structural and non-structural approaches. In this study, we propose the improvement of the flood control capacity in the Seomjin River basin through non-structural measures by optimizing the operation of the Seomjin River Dam, specifically by introducing a flexible flood season restricted water level (FSRWL). The flexible operation of FSRWL involves setting lower restricted water levels at the beginning of the flood season to increase flood control capacity and gradually raising them as the season progresses to manage flood control more effectively. As a structural measure, we examined the installation of riverside storage areas, a representative technique of nature-based solutions (NbS). Using the 2020 flood event as a case study, we analyzed the flood level reduction effects of implementing structural and non-structural measures both separately and simultaneously to identify the most effective and economical approach. The results indicate that the optimal flood prevention strategy for the main stream of the Seomjin River during the 2020 flood event involves operating the Seomjin River Dam FSRWL at EL. 190 m during the mid-flood season as a non-structural measure and installing a riverside storage area downstream of Godalgyo Bridge in Daepyeong-ri, Gokseong-gun as a structural measure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.735-747
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• 2023

In recent times, the sharp increase in extreme flood damages due to climate change has posed a challenge to effectively address flood-related issues solely relying on conventional flood management infrastructure. In response to this problem, this study aims to consider the effectiveness of nature-based flood management approaches, specifically levee retreat and relocation. To achieve this, we utilized a 1D numerical model, HEC-RAS, to analyze the flood reduction effects concerning floodwater levels, flow velocities, and time-dependent responses to a 100-year frequency flood event. The analysis results revealed that the effect of creating a flood buffer zone of the nature-based solution extends from upstream to downstream, reducing flood water levels by up to 30 cm. The selection of the flow roughness coefficient in consideration of the nature-based flood buffer space creation characteristics should be based on precise criteria and scientific evidence because it is sensitive to the flood control effect analysis results. Notably, floodwater levels increased in some expanded floodplain sections, and the reduction in flow velocities varied depending on the ratio of the expanded cross-sectional area. In conclusion, levee retreat and floodplain expansion are viable nature-based alternatives for effective flood management. However, a comprehensive design approach is essential considering flood control effects, flow velocity reduction, and the timing of peak water levels. This study offers insights into addressing the challenges of climate-induced extreme flooding and advancing flood management strategies.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.1-10
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• 2007

Reallocation procedure of multipurpose reservoir storage capacity between flood control and conservation is presented as an alternative to secure more water resources. Storage reallocation is an adaptive management mechanism for converting existing normal pool level of reservoirs to more beneficial uses without requirement for physical alteration. This study is intended to develop a reservoir storage reallocation methodology that allows increased water supply storage without minimizing adverse impacts on flood control. The methodology consists of flood control reservoir simulation for inflows with various return periods, flow routing from reservoir to a potential damage site, analyzing river carrying capacity, and reservoir yields estimation for reallocated storages. For the flood control model, a simulation model called Rigid ROM(Reservoir Operation Method) and HEC-5 are used. The approach is illustrated by applying it to two reservoirs system in Geum River basin. Especially with and without new project conditions are considered to analyze trade-offs between competing objectives.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.483-486
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• 2003

This paper presents how effective the detention storage is to control floods at a test watershed. HEC-HMS model was applied to simulate the effects of the storages of different levels and installation methods on the flood peak reduction. The results showed that the detention storage may significant reduce the flood peaks, and the effectiveness depends on the sizes of the storage and types of installation. The simulated peak values reduce considerably for the design storm events. The results also showed that alternatives to control flood may be evaluated using the model.

• KCID journal
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• v.10 no.1
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• pp.44-52
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• 2003

This study surveyed farming condition and the effects of nonpoint source pollution loading by cultivating in the flood control area of multi-purpose dams. According to the multi-purpose dam management regulation, cultivation can be permitted between norma

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.103-111
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• 2012

Works for dam heightening plan have dual purposes: flood disaster prevention by securing additional storage volume and river ecosystem conservation by supplying stream maintenance flow. Now, the dam heightening project is in progress and there are 93 dam heightened reservoir. After the dam heightening project, 2.2 hundred million ton of flood control volume in reservoirs will be secured. Thus it is necessary to evaluate the effects of the dam heightening project on watershed hydrology and stream hydraulics, and resulting flood damages. This study was aimed to assess the impact of outflow from the dam heightened reservoir group on the Whangryong river design flood. The HEC-HMS (Hydrologic Engineering Center-Hydrologic Modeling System) model was used for estimating flood discharge, while HEC-5 (Hydrologic Engineering Center-5) was used for reservoir routing. This study analysed flood reduction effect on 100yr and 200yr return periods about the before and after heightening of agricultural dams. Based on the results of this study, the reduction of flood peak discharge at downstream of the reservoir group was estimated to be about 41% and 53% for 100yr and 200yr frequencies, respectively.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.294-301
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• 2016

The underflow type movable weirs were arranged in a multi-stage way at a section of the Chiseong River, a tributary of Geum River, where flooding is observed frequently. The flood control and the movable weir management levels were compared with the occasions of installing the existing weir for analysis. The peak discharge decreased by a maximum of 97% for the underflow type movable weir, and the downstream flood elevation decreased by a maximum of 82%. The amount of storage also increased by a maximum of 463% by the distribution and storage functions of the multi-stage arrangement of the underflow type movable weirs. It is possible to suggest that the management level of each movable weir for the target storage of the reach and the flood reduction level through the relationship among this storage, downstream peak flood elevation, and peak flow.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.413-423
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• 2016

Effects of the design flood share of the Kyeongpo retarding basin, which has a function for flood control of the Kyeongpo river assigned to the Kyeongpo prickly water lily wetland, on the Kyeongpo lake and the downstream of Kyeongpo river were analyzed on the bassis of the hydraulic experiments and the numerical simulations using RMA-2 model. Reproducing a complex water flow system of the area of Kyeongpo lake, the unsteady flow simulations were performed. The data obtained in hydraulic experiments were used to determine parameters of the numerical model which simulated the flows for various flood scenarios in the downstream area of Kyeongpo river. With increasing the design flood share rates in the retarding basin, the water level was increased in the lake and is decreased in the river. The characteristics of flood flow interaction between Kyeongpo river and Kyeongpo lake were understood. These results may be used to management the Kyeongpo lake during flood season.

• KIEAE Journal
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• v.15 no.1
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• pp.129-137
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• 2015

The purpose of this study is to analyze the Tetsugakudo Kouen Collective Housing Development Project in Japan. Project implemented cooperatively by the Tokyo Metropolitan Government in charge of river management, Shinjuku and Nakano-ku responsible for park management, and the UR, a housing project developer. This project set a significant precedent for three-dimensional river use by realizing the three-dimensional integrated development of a flood control reservoir, a park, and collective housing. The major effectiveness of this project can be summarized into four points. 1) The costs borne by individual project developers were significantly reduced by realizing a high degree of application and multipurpose use of the land through a joint project. 2) This project, which was designed to accommodate rainfall of 30 to 40mm per hour, is expected to contribute to reducing flood damage and generating significant investment effects, in terms of asset value in downstream areas, thereby increasing flood control security. 3) Local disaster prevention function were enhanced by providing an evacuation site in the case of an earthquake. 4) The living environment was improved by adding the function of a park.