• Title/Summary/Keyword: Flood Protection

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Socio-economic and Environmental Impact Assessment in Agricultural Cultivation, Case Studies in Rice Cultivation and Shrimp Farming in the Mekong River Delta, Vietnam

  • Nguyen, Tran Nhan Tanh;Tran, Thi Hong Ngoc
    • Journal of Environmental Impact Assessment
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    • v.18 no.6
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    • pp.461-467
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    • 2009
  • This paper provides two case studies of environmental impacts with socio-economic values. The first case is on flood protection levees conducted from 2003 to 2004 in Phu Tan district, An Giang province. The impacts were found by comparing full flood protection levees area (FFPL) to non-full flood protection levees area (NFFPL). Participatory Rural Appraisal (PRA) tools per each group of rich, middle, and poor people were used to list the impacts. Then, major impacts were selected by ranking and interviewing 60 households per site, and assessed by Cost Benefit Analysis (CBA) in rice production from 1996 to 2002 between two areas. The tested research indicated moving system of NFFPL to that of FFPL lost about 11 million VND/ha/year. The second case is on impacts of Penaeid shrimp farming conducted in Duyen Hai District, Tra Vinh Province in 2004-2005. Ninety households and 12 local officials were interviewed. Four PRAs were conducted and 36 water samples were taken inside and outside shrimp pond to measure values of DO, COD, Fe total, TSS, N-$NO_3{^-}$, N-$NH_4{^+}$, P-$PO{_4}^{3-}$, and Chlorophyll-a. Research results showed only 36.7% of the households got profit from shrimp farming. Highest financial efficiency was 0.72 for the semi-intensive system. Tested water indicators showed surface water quality did not match Vietnamese standard for surface water in coastal area (TCVN 5943-1995) and in rain. The water was very muddy and contaminated by organic aluminum. Summarily, the impacts were clarified more obviously via adding socio-economic values to assessment. Importantly, the values were transformed to household's income which is an indicator for policy-makers to consider the impacts obviously. Besides, data of different group of people impacted are cases contributing to consideration of the impacts in an appropriate social level.

The study on the development of intelligent optical communication system to monitor flood and water pollution (홍수 및 수질 오염 감시용 지능형 고속 광 통신 시스템 개발에 관한 연구)

  • Lee, Jin-Young
    • Journal of Digital Convergence
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    • v.10 no.11
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    • pp.351-358
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    • 2012
  • This study is aimed at suggesting optical communication equipment that can deliver high quality video information in high speed, to efficiently handle the flood and water pollution in the river basin. This system is cheaper than existing equipment, and can monitor optical Internet as well as the condition of equipment. Generally, the communication equipment to prevent flood is installed in an unmanned control box and operated by the flood control office situated at the fiver mouth in a long distance section. Therefore, it is hard to promptly cope with communication interruptions, which occur by the cutting or aging of the optical cable. Under the circumstances, this study suggested an efficient system that can deliver high quality video information in high speed (Optical Transmission Convert System) by using optical fiber. The system also solves problems by making use of automatic protection switching (APS) when an accident happens. Its real-time monitoring function gives notice of the problem-occurring points. The system is expected to be widely used in various areas such as intelligent traffic systems.

Alternatives Development for Basin-wide Flood Mitigation Planning: A Case Study of Yeongsan River Basin (유역치수계획을 위한 대안수립: 영산강 유역의 사례연구)

  • Yi, Choong-Sung;Shim, Myung-Pil;Lee, Sang-Won
    • Journal of Korea Water Resources Association
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    • v.43 no.6
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    • pp.507-516
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    • 2010
  • The purpose of this study is to propose the alternative development method by means of determining the optimal project size from the economic viewpoint, improving the existing method depending on engineering aspects. To this end, this study defined the flood mitigation projects as the production activities carried out by inputs and outputs, and proposed the alternative development method on the basis of optimizing input and output combinations. This paper, as the case study of the proposed method, developed alternatives for the flood mitigation planning of Youngsan River Basin by determining the optimal project scale. As the result of determining optimal project size, the net benefit of the optimal alternative tended to be dependent on the net benefits of the large individual proposals. Due to such problem, the effect of relatively small individual proposals are underestimated and possibly be excluded from the optimal alternative, which may result in exclusion of the potential damaged regions protected by them from the flood mitigation project. Thus for the selective flood protection by region, individual proposals need to be categorized into the global measures and local measures according to the flood protection area.

Analysis of Two Dimensions Hydraulic Characteristic in Steep Meandering Channel (급경사 만곡부 하도의 2차원 수리특성 해석)

  • Park, Ki-Bum;Lim, Kee-Seok
    • Journal of Environmental Science International
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    • v.16 no.9
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    • pp.1039-1049
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    • 2007
  • This study analyzed two dimensions hydraulic characteristic for actual flood events in steep meandering channel. It could get analysis results as follows; A water level difference of downstream more great than one of upstream at inner and outer of meandering channel. It judged that a significance of downstream level could appear more greatly in meandering channel bank, hydraulic structure and flood inundation analysis. As velocity and depth analysis was shown that much amount flow passing fast velocity happened in meandering channel, it could help establishment of meandering channel bank. In this study, the results of two dimension hydraulic analysis results could help a counterpaln establishment for the flood inundation and bank collapse.

Flood Inundation Analysis in Urban Area Using XP-SWMM (XP-SWMM 모형을 이용한 도심지역 침수해석)

  • Kim, Jinsu;Lee, Wonho
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.1
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    • pp.29-36
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    • 2015
  • Current domestic research is to demonstrate the effectiveness and efficiencies of flood prevention measures through one-dimensional numerical analysis and this study's object is to help water managers to make the efficient decisions by applying the two-dimensional urban run off model XP-SWMM model in the flooded area and comparing with the flood prevention measures. Statistics were analyzed, based on the data collected from Cheongju Weather Service from 1967 to 2011 for 45 years. 50 years Flood frequency simulations of water flow capacity analysis of the target area for flooded areas $539,548m^2$, inundation depth 1.0 m, was analyzed by inundation time of 48 minutes. When comparing with the constructions of bypass road and underground storage facilities to increase the water flow capacity of A1 small drainage areas as flood protection, if you install a batching target underground detention basin with a capacity of $13,500m^3$, it is expected that the flood by rainfall with frequency of 50 years will be resolved completely. In preparation for extreme weather in the future flood mitigation measures, underground storage tank installation is considered a better efficient way.

A Method for Selecting a Structural Optimal Flood Mitigation Plan Using Analytic Hierarchy Process (계층화분석기법을 통한 구조물적 홍수방어 최적대안 선정 방안 연구)

  • Lee, Jeong-Ho;Jun, Young-Joon;Ahn, Jae-Hyun;Kim, Tae-Woong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.3
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    • pp.117-126
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    • 2009
  • Various dimensions of watershed structural/non-structural planning can be applied in comprehensive flood mitigation plan in a river basin. Especially structural counterplans have very broad and diverse nature as flood control facilities. It is not easy to find the optimum alternative to maximize the ability of a basin to reduce flood risk using a combination of structural counterplans. In addition, there is no standard for evaluating the performance of structural counterplans and for selecting optimal combination of them. This study focused on how to select the best alternative of a comprehensive watershed structural plan from various flood defense alternative candidates. By introducing an analytic hierarchy process, we would like to show how we decide the best alternative using standard worksheets developed in this study for economics and policy evaluation, and Expert Choice 11.5, which calculates weights for evaluation items. Based on the results from this study, we would like to suggest the best practice of a standardized watershed plan for flood protection.

Evaluation of Flood Control Capacity for Seongju Dam against Extreme Floods (이상강우에 대비한 성주댐의 홍수조절 능력 분석)

  • 권순국;한건연;서승덕;최혁준
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.6
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    • pp.109-118
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    • 2003
  • As a fundamental research to establish a safety operation plan for irrigation dams, this study presents hydrologic analysis conducted in Sungju Dam watershed based on various rainfall data. Especially those reservoirs without flood control feature are widely exposed to the risk of flooding, a safe and optimized operation program need to be improved against arbitrary flooding. In this study, reservoir routing program was developed and simulated for reservoir runoff estimation using WMS hydrology model. The model simulated the variations of reservoir elevation under the condition of open or closed emergency gate. In case of closed emergency gate, water surface elevation was given as 193.15 m, and this value exceeds the dam crest height by 1.65 m. When the emergency gate is open, the increment of water surface elevation is given as 192.01 m, and this value exceeds dam crest height by 0.57 m. As an alternative plan, dam height increase can be considered for flood control under the PMP (Probable Maximum Precipitation) condition. Since the dam size is relatively small compare to the watershed area, sound protection can be expected from the latter option rather than emergency gate installation.

A Study on Optimized Placement of Green-Gray Infrastructure for Effective Flood Mitigation (효과적인 도시 홍수 저감을 위한 그린-그레이 인프라 위치 설정에 관한 연구)

  • Bae, Chae-Young;Lee, Dong-Kun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.25 no.6
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    • pp.65-75
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    • 2022
  • Urban flood management(UFM) strategy ought to consider the connections and interactions between existing and new infrastructures to manage stormwater and improve the capacity to treat water. It is also important to demonstrate strategies that can be implemented to reduce the flow at flooding sources and minimize flood risk at critical locations. Although the general theory of spatial impact is popular, modeling guidelines that can provide information for implementation in real-world plans are still lacking. Under such background, this study conducted a modeling research based on an actual target site to confirm the hypothesis that it is appropriate to install green infrastructure(GI) in the source area and to take structural protection measures in the impact area, as summarized in previous studies. The results of the study proved the hypothesis, but the results were different from the hypothesis depending on which hydrological performance indicators were targeted. This study will contribute to demonstrating the effectiveness of strategies that can be implemented to reduce the flow at flooding sources and minimize the risk of flooding in critical locations in terms of spatial planning and regeneration.

Characteristics of Bed Profile Fluctuation According to Before & After Removal of the Sediment Protection Weir using HEC-6 model (HEC-6모형을 이용한 방사보 철거 전후에 따른 하상변동 특성)

  • Ahn, Seung-Seop;Lee, Soo-Sik;Choi, Yun-Young;Lee, Jeung-Seok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.1 no.3 s.3
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    • pp.93-102
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    • 2001
  • In this study, the characteristics of river bed profile fluctuation are become possible to be used effectively in future estimation of Taehwa river general development plan through analysis and examination according to the effects of sediment protection weir located in the area of the estuary of Taehwa river's main channel using HEC-6 model. The flow conditions needed in analysis of the characteristics of river bed profile fluctuation refer the conditions of flow which secures 95 days in a year, flood flow, and design flood examined in the estimation of Taehwa river maintenance basic plan. First, in analysis result of river bed variation range, there is no significant variation in upstream section from Samho-gyo while there are the more active erosion and sedimentation as the more flow in downstream from Samho-gyo. Next, from the result of the capacity of sediment transfer, it is analyzed that sediment transfer capacity in the area of estuary of Taehwa river has no significant difference in before and after removal of the sediment protection weir when design flood flows while it is estimated that the more flow, the bigger sediment transfer capacity. Therefore, it is thought that the installation of a suitable hydraulic structure at the lowest point of Dong-chun tributary joins from the downstream of Taehwa river can be a good device to reduce the accumulation of sediments at the lowest point of Taehwa river considering the reduction plan of sediment inflow caused by removal of the sediment protection weir.

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