• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.2 s.17
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• pp.17-28
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• 2005

The objective of this study is to evaluate the critical duration between detention facility and flood control facility of small size catchment. 4 small size catchments are applied for hydrological analysis and rainfall excess is computed by using the NRCS Runoff Curve Number method. The critical duration of detention facility and flood control facility is evaluated using the concept of allowable release rate. The conclusions studied in this study are as follows; (1) The type of temporal pattern of design rainfall which causes maximum storage ratio has resulted in Huff's 2 quartile in case of the use of the concept of allowable release rate. (2) Based on (1) of conclusion, the critical durations of flood control facility are similar to those of detention facility, which is used for uncontrolled single detention pond.

• KIEAE Journal
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• v.10 no.4
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• pp.9-17
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• 2010

The purpose of this study is to draw out objective bases for selecting various applicable facilities in case of the establishment of rainwater management strategies. To do so, sixteen facilities were selected from decentralized rainwater management systems that induce rainwater infiltration and detention as well as centralized end-of-pipe type infiltration and detention facilities in local areas. With these facilities, it attempted to evaluate them in terms of sustainability, pollutant elimination, flood control capacity and costs and subsequently analyzed correlations between each characteristic. The outcomes of the analysis were as follows: First was the analysis of characteristics between decentralized rainwater management systems and end-of-pipe rainwater management systems. From the decentralized rainwater management systems, the mulden-rigolen system and grass swale at street level had the highest in the total of the four items while the totals of the underground detention tank and temporary detention site were highest in end-of-pipe rainwater management systems. After analyzing the correlation between different types of facilities and each variable, it can be said that decentralized rainwater management systems have a higher correlation than end-of-pipe rainwater management systems in terms of sustainability whereas the latter are better in flood control capacity than the former. Second, the analysis of correlation in variables of each facility is as follows: first, there is a negative correlation between sustainability value and flood control capacity value; and there is a positive correlation between flood control capability and pollutants elimination. In addition, it revealed that the higher the flood control and pollutant elimination capability the higher the facility costs. Based on these assessments, it is possible to use them as objective selection criteria for facility application in case of site development project or complex plan.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.217-225
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• 2023

This study analyzed the effect of flood level reduction in the case of creating and operating offline storage for the Jangdong district, which can be used as a flood buffer space for the Geumgang River, through one-dimensional unsteady flow numerical simulation. In particular, the sensitivity analysis of changes in the height and width (length) of transverse weirs on flood level changes was performed to provide quantitative information necessary for flood control facility (embankment) design. As a result of analyzing the flood control effect of the offline storage based on the peak flood discharge and level, spatially, the flood control effect at the planned flood buffer space site and the downstream end was confirmed, and it was confirmed that the flood reduction effect at the downstream occurred the most. By design conditions of the transverse overflow weir, the greatest flood reduction effect was found under the condition that the overflow weir height based on the 50-year frequency flood level and the transverse overflow weir width (length) of 125 m were considered. The effect of delaying the time to reach the maximum flood due to the operation of the offline storage site was also presented based on unsteady flow modeling.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.1012-1017
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• 2007

Rain data and water-level data are importantly used for dam operation at flood period. Because dams are directly controlled by the water-level data, the characteristic of the water-level gauges is necessary to be managed. Thus, we developed the standard test facility and method for testing the water-level gauges which are a float type, a supersonic type and a radar type. And we calculated the uncertainty of the standard test facility to maintain the accuracy of water-level gauges. Through development of this facility, we could obtain the characteristics and the calibration factor of the water-level gauges. And, this study showed that the standard test facility can be widely used for dam operation and basin management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.259-266
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• 2023

Global climate change is increasing, and the damage and scale of localized torrential rains are increasing. Pre-flood analysis simulation results should be derived from rainfall data through rainfall forecasts to prevent flood damage. In addition, it is necessary to control the use and management of flood response disaster prevention facilities through immediate decision-making. However, methods using spills and flood models such as XPSWMM and GATE2018 are limited due to professional usability and complex analytical procedures. Prototype (flood disaster prevention facility simulator) of this study is developed by calculating rainfall (short-term and long-term) using CBD software development methods. It is also expected to construct administrator and user-centric interfaces and provide GIS and visible data (graphs, charts, etc.).

• Journal of Environmental Impact Assessment
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• v.16 no.3
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• pp.187-194
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• 2007

It started road constructions around river in 1990s. These maintenances concentrate on city river. Because river lives no living things and men don't come near there. But in spite of these river environment go to rack, river maintenances still keep on using preexistence method since 1990s. Only a part of city river environment maintenances consider environmental ability of passive river, river maintenance of a purpose of flood control still don't consider in the concrete. Because propulsion device that consider environment ability of passive river and possible application techniques don't complete. In accordance, A natural river maintenance needs absolutly a series of river projects. Because a natural river maintenance prevents a damage of environment ability. This study is to assume the flood really happened and to carry out the flood damage simulation needed in overflow simulation about the inundated zone. Also, This study examine unstable part about the hydraulic characteristic as velocities, stream power, shear, hydraulic depth, flow area in basin. And this study applied the HEC-RAS(river analysis system) model to predict flood overflow in youngsan river basin. Project flood is used the return period 100 year and inputed data that was calculated in intensity figures of illumination.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.135-144
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• 2006

The significance of hydro-power plant is increasing in its public roles such as flood control and water supply as well as electric power production. Even if high level of reliability in facility operation is required, no specific reliability research has been made. This specifically stems from the lack of technology and research investments. The eventual goal of this study is to secure a methodology for reliability analysis of hydro-power plant so that an appropriate decision for operation and investment can be made. Specific effort was put to develop a reliability model for water supply system within hydro-power plant. For this study, we briefly examined the overview of the hydro-power plant including the electric power generation facility system. We then discussed the facility reliability analysis methodology for hydro-power plant. Based on rigorous examination of the water supply system and components roles, we drew major failure modes for each component and examined their effects.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.363-369
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• 2006

A simple and an improved methods for the economic analysis of the flood control project has been in previous studies in Korea. In 2004, the Multi-Dimensional Flood Damage Analysis (MD-FDA) was developed and now it is widely used for the economic analysis of flood control project. However, the MD-FDA was developed for general damage assessment and analysis without consideration of specific regional characteristics such as urban and rural areas. To compensate the MD-FDA for the application in urban area, a part of damage estimation components is modified and a component for the flood damage estimation is suggested. The component we suggest is for the consideration of the capability of stormwater pump stations in the study area. When flood is occurred in the urban area, the damage potential is larger than the rural area because of the concentration of human lives and properties. So, many stormwater pump stations are located in the urban area and the inundation depth is estimated by considering the capabilities of pump stations. We also compensate the damage components such as the damages of industrial area, and public facilities for the flood damage estimation of the urban area. The results by the compensated MD-FDA for the urban area application with those by original MD-FDA are compared. As a result the B/C ratio showed 6.75 and 5.51 respectively for the modified and original MD-FDA. This difference might be largely affected by the damage rate of the public facilities.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.145-150
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• 2009

Because it is difficult to install new large hydraulic structure, washland is considered as alternatives of hydraulic facility. As flood reduction effect of washland is dependent on flood, hydrograph, capacity of washland and spillway height, applying adequate spillway height is very important to maximize flood reduction effect of washland. In this study, effect of variation of spillway height on flood reduction effect of washlands is analyzed. The existing model developed to make decision for optimal location of washland using flood reduction effect as evaluation function and location of washland as decision variable was revised for this purpose. The spillway height of washland is added as decision variable and revised model finally give optimal location and spillway height of washland as result. The developed model has been applied to the Ansung River basin and application result was compared with that of existing model. The application result shows that developed model can give more efficient result than existing model.