• Title/Summary/Keyword: Flood Prevention

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Determining the Flash Flood Warning Trigger Rainfall using GIS (GIS를 활용한 돌발홍수 기준우량 결정)

  • Hwang, Chang-Sup;Jun, Kye-Won;Yeon, In-Sung
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.1
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    • pp.78-88
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    • 2006
  • This paper is to apply Geographical Information System (GIS) supported Geomorphoclimatic Instantaneous Unit Hydrograph (GCIUH) approach for the calculated flash flood trigger rainfall of the mountainous area. GIS techniques was applied in geography data construction such as average slope, drainage area, channel characteristics. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. We compared the GCIUH peak discharge with the existing report using the design storm at Chundong basin($14.58km^2$). The results showed that derived the GCIUH was a very proper method in the calculation of mountaunous discharge. At the Chundong basin, flash flood trigger rainfall was 12.57mm in the first 20 minutes when the threshold discharge was $11.42m^3/sec$.

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Strategies for Providing Detour Route Information and Traffic Flow Management for Flood Disasters (수해 재난 시 우회교통정보 제공 및 교통류 관리전략)

  • Sin, Seong-Il;Jo, Yong-Chan;Lee, Chang-Ju
    • Journal of Korean Society of Transportation
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    • v.25 no.6
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    • pp.33-42
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    • 2007
  • This research proposes strategies about providing detour route information and traffic management for flood disasters. Suggested strategies are based on prevention and preparation concepts including prediction, optimization, and simulation in order to minimize damage. Specifically, this study shows the possibility that average travel speed is increased by proper signal progression during downpours or heavy snowfalls. In addition, in order to protect the drivers and vehicles from dangerous situations, this study proposes a route guidance strategy based on variational inequalities such as flooding. However, other roads can have traffic congestion by the suggested strategies. Thus, this study also shows the possibility to solve traffic congestion of other roads in networks with emergency signal modes.

Countermeasure and Mitigation to Flood Disaster in Japan (일본(日本)의 하천방재(河川防災) 대책(對策)에 대한 연구(研究))

  • Rim, Byung Dae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.117-127
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    • 1992
  • Japan is situated in the zone attacked repeatedly by typhoon. She is apt to be given by the nature damage like flood and loss the life and the property conventionally because of her short channel and steep slope ground. This paper is centered on the method of analysis and the damage management of river which are based on the Bulletin of the Disaster Prevention Research Institute of Kyoto University. The field of flood disaster, submersion damage, water proof system, debris control disaster and water resources are studied respectely. The river management examples which are done by Foundation of River and Basin Integrated Communications and The Yodo River are analyzed. The above analysis helps to control disaster of river in Korea.

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Estimation of Superelevation in Mountainous River Bends (산지하천 만곡부의 편수위 산정)

  • Park, Sang Doeg;Lee, Seung Kyu;Shin, Seung Sook;Cho, Jaewoong
    • Journal of Korea Water Resources Association
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    • v.47 no.12
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    • pp.1165-1176
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    • 2014
  • In a river bend the water surface is inclined by the centrifugal force toward the transverse section. If channel slope and flow rate increase, the gradient is rising generally. There are lots of the flood damage at the bends of mountain river because the flood water levels have exceeded frequently the levee levels which are added a free board to the design flood water level. Therefore the superelevation should be considered in designing the mountainous river bend. In present study it was proposed to estimate the superelevation at the bend of mountain river and the superelevation coefficient defined from multiplying the sub-factors. The values of the influence factors for the superelevation coefficient were suggested from analyzing the superelevation measured at the bends in Yangyangnamdae river and the hydraulic experiments in gravel-bed channel with a $90^{\circ}$ bend. The applicability of these methods to estimate the superelevation at the bends in mountain river was verified by the superelevation measured at the bend in Naerin river.

Characterization of Physical Properties of Turbid Flow in the Daecheong Reservoir Watershed dining Floods (홍수시 대청호 유역에 발생하는 탁수의 물리적 특성)

  • Chung, Se Woong;Lee, Heung Soo;Yoon, Sung Wan;Ye, Lyeong;Lee, Jun Ho;Choo, Chang Oh
    • Journal of Korean Society on Water Environment
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    • v.23 no.6
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    • pp.934-944
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    • 2007
  • Fine suspended solids (SS) induced into a reservoir after flood events play important ecological and water quality roles by presenting persistent turbidity and attenuating light. Thus the origin and physical features must be characterized to understand their transport processes and associated impacts, and for the establishment of watershed based prevention strategies. This study was aimed to characterize the physical properties of the SS sampled from Daecheong Reservoir and its upstream rivers during flood events. Extensive field and laboratory experiments were carried out to identify the turbidity-SS relationships, particle size distributions, settling velocity, and mineral compositions of the SS. Results showed that the turbidity-SS relationships are site-specific depending on the locations and flood events in the system. The turbidity measured within the reservoir was much greater than that measured in the upstream rivers for the same SS value. The effective diameters ($D_{50}$) in the rivers were in the range of $13.3{\sim}54.3{\mu}m$, while those in the reservoir were reduced to $2.5{\sim}14.0{\mu}m$ due to a fast settling of large particles in the rivers. The major minerals consisting of the SS were found to be Illite, Muscovite, Albite, and Quartz both in the rivers and reservoir. Their apparent settling velocities at various locations in the reservoir were in the range of 0.06~0.13 m/day. The research outcome provides a fundamental information for the fine suspended particles that cause persistent turbidity in the reservoir, and can be used as basic parameters for modeling study to search watershed based optimal control measures.

An Analysis on the Changes of flow Duration Characteristics due to Dam Construction (댐 건설에 따른 하류 유황의 변화 분석)

  • Kim, Tae-Gyun;Yoon, Yong-Nam;Ahn, Hae-Hyun
    • Journal of Korea Water Resources Association
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    • v.35 no.6
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    • pp.807-816
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    • 2002
  • The purpose of the present study was to evaluate the changes of flow duration characteristics of a large river basin due to construction of a dam. The changes of water surface are quantified from remote sensing film taken before and after dam construction. Gongiu gauging station was selected to analyze the changes of flow duration, and annual exceedance series of Gongju and Kyuam gauging station were selected to estimate the changes of flood quantile before and after dam construction. From the analysing results, it was found that the construction of dam contributes to make new duration stable and to decrease flood flow. In conclusion, it was confirmed that the construction of the dam is useful for water supply and flood prevention.

Development of Flooding and Overflow Simulation Technology for Rainwater Infiltration Storage Block Placement (빗물침투저류블록 설치 최적지 선정을 위한 침수범람 시뮬레이션 기술 개발)

  • Kim, Seongpyo;Ryu, Jungrim;Kim, Hojin;Choi, Heeyong;Lee, Taegyu;Choi, Hyeonggil
    • Journal of the Korea Institute of Building Construction
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    • v.24 no.2
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    • pp.227-238
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    • 2024
  • This study addresses the escalating flood damages prompted by recent climate shifts characterized by extreme weather events and proposes rainwater infiltration blocks as a potential solution. Recognizing the limitations inherent in existing inundation simulation methods, we advocate for the integration of novel functionalities, particularly leveraging drone technology. Our research endeavors encompass experimental assessments of inundation and flooding simulation technologies. These evaluations are conducted within areas where rainwater infiltration storage blocks have been implemented, juxtaposed against existing programs utilizing Digital Elevation Models(DEM) and Digital Surface Models(DSM). Through this comparative analysis and a meticulous scrutiny of the adaptability of inundation and flooding simulation to real-world deployment scenarios, we ascertain the efficacy of the simulation program as a decision-making tool for identifying optimal sites for rainwater infiltration storage block installation.

Designing a Decentralized Stormwater Management Corridor for a Flood-Prone Watershed using Surface Runoff Analysis (지표유출수 분석을 통한 상습침수유역의 분산식 우수관리통로 설계)

  • Lee, Seul;Lee, Yumi
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.3
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    • pp.13-26
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    • 2015
  • Many urban areas in Korea suffer from repeated flood damage during intensive rainfall due to an increase in impervious areas caused by rapid urbanization and deteriorating sewage systems. A centralized stormwater management system has caused severe flood damage in an area that has proven unable to accommodate recent climate change and a rise in precipitation. Most flooding prevention projects that have been recently implemented focus on increasing drainage system capacity by expanding the size of sewer pipes and adding pumping stations in downstream areas. However, such measures fail to provide sustainable solutions since they cannot solve fundamental problems to reduce surface runoff caused by urbanization across the watershed. A decentralized stormwater management system is needed that can minimize surface runoff and maximize localized retention capacity, while maintaining the existing drainage systems. This study proposes a stormwater management corridor for the flood-prone watershed in the city of Dongducheon. The corridor would connect the upstream, midstream, and downstream zones using various methods for reducing stormwater runoff. The research analyzed surface runoff patterns generated across the watershed using the Modified Rational Method considering the natural topography, land cover, and soil characteristics of each sub-watershed, as well as the urban fabric and land use. The expected effects of the design were verified by the retainable volume of stormwater runoff as based on the design application. The results suggest that an open space network serve as an urban green infrastructure, potentially expanding the functional and scenic values of the landscape. This method is more sustainable and effective than an engineering-based one, and can be applied to sustainable planning and management in flood-prone urban areas.

Tunnelling in Bangkok - Two Case Studies (방콕의 터널공사 - 두 개의 사례연구)

  • Teparaksa, Wanchai;Cho, Gye-Chun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.2
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    • pp.153-163
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    • 2005
  • This paper presents two case studies for tunnelling in Bangkok: a subway tunnel site and a flood diversion tunnel site. The first case study is related to ground displacement response for dual tunnel Bangkok MRT subway. The MRT subway project of Bangkok city consists of dual tunnels about 20 km long with 18 subway stations. The tunnels are seated in the firm first stiff silty clay layer between 15-22 m in depth below ground surface. The behavior of ground deformation response based on instrumentation is presented. The back analysis based on plain strain FEM analysis is also presented and agrees with field performance. The shear strain of FEM analysis is in the range of 0.1-1% and in accordance with the results of self boring pressuremeter tests. Meanwhile, the second case study is related to the EPB tunnelling bored underneath through underground obstruction. The Premprachakorn flood diversion tunnel is the shortcut tunnel to divert the flood water in rainy season into the Choapraya river. The tunnel was bored by means of EPB shield tunnelling in very stiff silty clay layer at about 20-24 m in depth. During flood diversion tunnel bored underneath the existing Bangkok main water supply tunnel and pile foundation of the bridge, instrumentation was monitored and compared with predicted FEM analysis. The prevention risk potential by means of predicting damage assessment is also presented and discussed.

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Connection of Hydrologic and Hydraulic Models for Flood Forecasting in a Large Urban Watershed (대규모 도시유역의 홍수예보를 위한 수리.수문 모형의 연계)

  • Yoon, Seong-Sim;Choi, Chul-Kwan;Bae, Deg-Hyo
    • Journal of Korea Water Resources Association
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    • v.41 no.9
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    • pp.929-941
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    • 2008
  • The objectives of this study are to propose a system for combined use of a hydrologic and a hydraulic model for urban flood forecast model and to evaluate the system on the $300km^2$ Jungrang urban watershed area, which is relatively large area as an urban watershed and consequently composed of very complex drainage pipes and streams with different land uses. In this study, SWMM for hydrologic model and HEC-RAS for hydraulic model are used and the study area is divided into 25 subbasins. The SWMM model is used for sewer drainage analysis within each subbasin, while HEC-RAS for unstready flow analysis in the channel streams. Also, this study develops a GUI system composed of mean areal precipitation input component, hydrologic runoff analysis component, stream channel routing component, and graphical representation of model output. The proposed system was calibrated for the model parameters and verified for the model applicability by using the observation data. The correlation coefficients between simulated and observed flows at the 2 important locations were ranged on 0.83-0.98, while the coefficients of model efficiency on 0.60-0.92 for the verification periods. This study also provided the possibilities of manhole overflows and channel bank inundation through the calculated water profile of longitudinal and channel sections, respectively. It can be concluded that the proposed system can be used as a surface runoff and channel routing models for urban flood forecast over the large watershed area.