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1.
Bangladesh is a country that comprises much of the world’s largest delta, formed from the Ganges, Brahmaputra, and Meghna (GBM) rivers and their tributaries. Flooding is a fact of life in Bangladesh where up to two-thirds of the country is flooded annually from combined monsoonal rains and Himalayan snowmelt. For this reason, understanding flood dynamics on both local and regional scales is critical. However, flood hazard studies to date typically rely on single flooding events to create flood maps and to evaluate flood hazards using satellite imagery. Here we use geographic information systems to analyze weekly water level data from 304 river gauges and over 1200 groundwater gauges from the Bangladesh Water Development Board to determine the spatial and temporal changes in flood depth and extent. These data cover an eight year period from 2002 to 2010 and provide a temporal resolution that match or are better than that of available satellite imagery. Country-wide ground and surface water levels and corresponding annual flooding events were determined along with groundwater level, flooding, and precipitation trends in Bangladesh at multiple scales. We find that while precipitation within the GBM basin has steadily increased through the time series, the average country-wide inundation depth and absolute water level has been decreasing. These respective trends could be attributed to improved flood management strategies in Bangladesh and surrounding countries that are within the GBM basin, as well as fluctuating weather patterns, declining volume of Himalayan snowmelt runoff, dam construction upriver from the GBD both within and outside the Bangladesh border, and increased groundwater abstraction of shallow groundwater aquifers for sustaining life in the eighth most populous country in the world. 相似文献
2.
Poverty, vulnerability and the impact of flooding
in the Limpopo Province, South Africa 总被引：1，自引：0，他引：1
The article evaluates household vulnerability after the 2000 flood in two poor communities of the Limpopo Province, South
Africa. The study analyses the forms of vulnerability which disasters such as floods present. Using data gathered from a survey
of households, the study presents the impacts, coping and adapting strategies of households after the 2000 flood. The article
argues that beyond the concern over socio-economic circumstances as the major determinant of household vulnerability, the
management of the disaster can serve to perpetuate vulnerability. 相似文献
3.
This article evaluates some of the factors which limit the human benefits of hazard warnings, with specific reference to flood
warnings, and we conclude by suggesting ways of enhancing these benefits. We focus mainly upon the economic benefits generated
by flood damage savings by households that warnings facilitate; health effects of flooding and flood warnings; and the effects
of warnings on loss of life and physical injury. Our results, based partly upon surveys of flooded households, reveal that
economic benefits are currently more limited than we previously thought, but that for several reasons these benefits are likely
to be under-estimated. We argue that the intangible benefits to public health, safety and security must also be taken into
account in decisions about investment in flood warnings. In England and Wales, the public’s response to flood warnings is
currently low and is a key benefit-limiting factor which could begin to undermine a recent major shift in national flood risk
management policy towards a more people-centred, portfolio approach in which changing human behaviour is viewed as important.
Using a trans-disciplinary approach, we discuss the evidence and literature surrounding this poor response, and suggest a
number of ways in which the issue may be addressed in future. 相似文献
4.
Bruce Frayne 《Geoforum》2004,35(4):489-505
Based on recent research in Windhoek, this paper demonstrates that it is the well established and widespread social linkages that persist between rural and urban households that are central to the ability of poor urban households to survive. Whereas informal coping mechanisms that include borrowing, piecework and credit are pervasive in rural areas of Namibia, intra-urban sources of food are poorly developed, and outside of kinship circles, social networks within Windhoek are used sparingly, even in times of greatest need. In addition, urban agriculture plays a very limited role at present in urban food supply. The research demonstrates that urban households that are most vulnerable to hunger are those that have limited social connections to the rural areas, and must rely on intra-urban opportunities to get food (including borrowing, begging, piecework and crime). The most vulnerable are female- and male-headed households with no access to farm income and limited/irregular urban incomes. In contrast, those with active rural-urban linkages enjoy significant transfers of food from rural areas that offset hunger and vulnerability in the urban context. Urban-rural reciprocity is therefore not only a one-way movement of people and resources from the urban to the rural areas, but also a transfer of food from rural to urban households. 相似文献
5.
Flood disasters and its consequent damages are on the rise globally. Pakistan has been experiencing an increase in flood frequency and severity along with resultant damages in the past. In addition to the regular practices of loss and damage estimation, current focus is on risk assessment of hazard-prone communities. Risk measurement is complex as scholars engaged in disaster science and management use different quantitative models with diverse interpretations. This study tries to provide clarity in conceptualizing disaster risk and proposes a risk assessment methodology with constituent components such as hazard, vulnerability (exposure and sensitivity) and coping/adaptive capacity. Three communities from different urban centers in Pakistan have been selected based on high flood frequency and intensity. A primary survey was conducted in selected urban communities to capture data on a number of variables relating to flood hazard, vulnerability and capacity to compute flood risk index. Households were categorized into different risk levels, such as can manage risk, can survive and cope, and cannot cope. It was found that risk levels varied significantly across the households of the three communities. Metropolitan city was found to be highly vulnerable as compared to smaller cities due to weak capacity. Households living in medium town had devised coping mechanisms to manage risk. The proposed methodology is tested and found operational for risk assessment of flood-prone areas and communities irrespective of locations and countries. 相似文献
6.
为定量评估分蓄洪工程启用过程中蓄滞洪区的洪水风险等级,创建了基于力学过程的蓄滞洪区洪水风险评估模型。该模型采用二维水动力学模块计算蓄滞洪区的洪水演进过程,利用洪水中人体跌倒失稳公式及洪水中房屋、农作物损失的计算关系式,评估各类受淹对象的洪水风险等级。然后将二维水动力学模块计算的洪水要素与两个物理模型试验值进行对比,表明二维水动力学模块的计算精度良好。最后计算了荆江分洪工程启用时分洪区内洪水的演进过程,并评估洪灾中群众的危险等级和财产损失。计算结果表明:洪水演进至140 h时,蓄滞洪区群众、房屋、水稻和棉花的平均损失率分别为85%、59%、63%和72%。模型中提出的采用基于受淹对象失稳机制的洪水风险分析方法,比以往经验水深法划分风险等级的适用性更好,不仅能为洪水风险管理及蓄滞洪区启用标准制定提供参考,也能推广应用于溃坝或堰塞湖溃决等极端洪水风险评估。 相似文献
7.
In this study, an agent-based model is proposed in order to provide new insights into the policy analysis and strategy assessment of city-scale evacuation management. The proposed model is suitable for assessment of the influence of different departure times and communications among peer evacuees on the number of residents at risk who arrive at official shelters. A case study is applied to build a simulation model for the coastal city of Brisbane in Australia. The Brisbane River catchment experiences regular flooding almost every year; the second severest flood since the twentieth century occurred in 2011. During that event, over 15,000 properties were inundated and around 3600 households evacuated in metropolitan Brisbane alone. Making use of high-performance computing clusters, the evacuation simulation was coupled with results from a validated hydrodynamic model to test a variety of escaping scenarios based on the 2011 flood situation. This case study demonstrates the proposed model’s capacity to represent the dynamic evacuation process and also shows that the model is able to help develop flood emergency plans and evaluate response measures through exploring key elements in a range of scenarios. 相似文献
8.
Informal settlements are an important source of affordable housing and economic activity in developing cities. Research shows that informal settlements are at high risk from natural hazards and the effects of global climate change. Conditions within such settlements are diverse, however, and it is important that we understand the variation in risk across households. In this paper, we study the uneven terrain of risk to localized hazards in informal settlements in Kolkata, India. Our research question is, which factors predict household exposure to monsoon rain hazards? We surveyed 414 households living in low-lying informal settlements on the city’s periphery. Using a variety of predictors, we estimate binary logistic models for two outcome variables tied to monsoon rain: home flooding and home leaking. We find that household exposure varies significantly across our study population and follows predictable patterns based on socio-economic and infrastructure variables. The home flooding model results show that households with higher incomes are less likely to flood, but in situ births increase exposure. Households living in structures made of more permanent materials are less likely to flood, as are households living near infrastructure. The home leaking model shows that households with relative financial stability are less likely to leak, as are those that have been living in the settlement for longer periods of time and whose houses are made of better quality materials. These findings indicate that extensive risk in informal settlements is unevenly experienced and that policies intended to reduce disaster and climate risk should focus on the lowest-income households, the provision of infrastructure, and security of tenure. 相似文献
9.
A maximum difference conjoint (MDC) model was part of a questionnaire toassess floodplain residents' preferences for the outcomes of water level managementinside an enclosed embankment system on the left bank of the Dhaleswari River, calledthe Compartmentalization Pilot Project (CPP)-Tangail. The outcomes were described as(a) varied flood depths in the rice field, (b) incidence of flooding on the courtyard andinside homes, (c) changes in floodplain and culture fisheries, and (d) varied conditionsof drainage congestion. Following a standard survey, the respondents from inside andoutside a completed section of the compartment (Cluster 1b) were shown profiles of these flood management outcomes and were asked to indicate for each profile the one most preferred and the one least preferred item. The results of the study indicated that the respondents had a clear preference for preventing flooding of their homes and courtyards and for an ideal water depth of 2 ft in the aman rice fields. At the same time, they also showed a strong concern about malfunctioning of sluices and to a lesser extent about the changes in the fish habitat. The successful application of the MDC as an approach to model tradeoffs among rural residents of Bangladesh shows that a relatively complex quantitative survey method, incorporating choice cards as pictograms, can be applied successfully even in a developing country. 相似文献
10.
The 4th IPCC report highlights the increased vulnerability of the coastal areas from floods due to sea-level rise (SLR).
The existing coastal flood control structures in Bangladesh are not adequate to adapt these changes and new measures are urgently
necessary. It is important to determine the impacts of SLR on flooding to analyse the performance of the existing structures
and corresponding impact to plan for suitable adaptation and mitigation measures to reduce the impacts of floods on coastal
zone. The study aims to develop a comprehensive understanding of the possible effects of SLR on floods in the coastal zone
of Bangladesh. A hydrodynamic model, which is a combination of surface and river parts, was utilized for flood simulation.
The tool was applied under a range of future scenarios, and results indicate both spatial variability of risk and changes
in flood characteristics between now and under SLR. Estimated impact on population, infrastructure and transportation is also
exposed. These types of impact estimation would be of value to flood plain management authorities to minimize the socio-economic
impact. 相似文献
11.
12.
Coupled 1D–2D hydrodynamic models are widely utilized in flood hazard mapping. Previous studies adopted conceptual hydrological models or 1D hydrodynamic models to evaluate the impact of drainage density on river flow. However, the drainage density affects not only river flow, but also the flooded area and location. Therefore, this work adopts the 1D–2D model SOBEK to investigate the impact of drainage density on river flow. The uncertainty of drainage density in flood hazard mapping is assessed by a designed case and a real case, Yanshuixi Drainage in Tainan, Taiwan. Analytical results indicate that under the same return period rainfall, reduction in tributary drainages in a model (indicating a lower drainage density) results in an underestimate of the flooded area in tributary drainages. This underestimate causes higher peak discharges and total volume of discharges in the drainages, leading to flooding in certain downstream reaches, thereby overestimating the flooded area. The uncertainty of drainage density decreases with increased rainfall. We suggest that modeling flood hazard mapping with low return period rainfalls requires tributary drainages. For extreme rainfall events, a lower drainage density could be selected, but the drainage density of local key areas should be raised.
相似文献13.
Effective livelihood adaptation to climate change disturbance: Scale dimensions of practice in Mozambique 总被引：2，自引：0，他引：2
Natural resource-dependent societies in developing countries are facing increased pressures linked to global climate change. While social-ecological systems evolve to accommodate variability, there is growing evidence that changes in drought, storm and flood extremes are increasing exposure of currently vulnerable populations. In many countries in Africa, these pressures are compounded by disruption to institutions and variability in livelihoods and income. The interactions of both rapid and slow onset livelihood disturbance contribute to enduring poverty and slow processes of rural livelihood renewal across a complex landscape. We explore cross-scale dynamics in coping and adaptation response, drawing on qualitative data from a case study in Mozambique. The research characterises the engagements across multiple institutional scales and the types of agents involved, providing insight into emergent conditions for adaptation to climate change in rural economies. The analysis explores local responses to climate shocks, food security and poverty reduction, through informal institutions, forms of livelihood diversification and collective land-use systems that allow reciprocity, flexibility and the ability to buffer shocks. However, the analysis shows that agricultural initiatives have helped to facilitate effective livelihood renewal, through the reorganisation of social institutions and opportunities for communication, innovation and micro-credit. Although there are challenges to mainstreaming adaptation at different scales, this research shows why it is critical to assess how policies can protect conditions for emergence of livelihood transformation. 相似文献
14.
Jan Klimeš Miroslava Benešová Vít Vilímek Petr Bouška Alejo Cochachin Rapre 《Natural Hazards》2014,71(3):1617-1638
In April 2010, an ice/rockfall into Lake 513 triggered a glacial lake outburst flood (GLOF) along the Chucchun River in the Cordillera Blanca of Peru. This paper reconstructs the hydrological characteristics of this as yet undocumented event using a 1D flood model prepared with HEC-RAS. The principle model inputs were obtained during detailed field surveys of surface characteristics and topography within the river and across the adjacent floodplain; a total of 120 cross-sections were surveyed. These inputs were refined further by eyewitness accounts and additional geomorphological observations. The flood modelling has enabled us to constrain the extent of the water surface and its elevation at each cross-section in addition to defining the peak discharge (580 m3 s?1). These modelling results show good agreement with other information about the flood including: flood marks and minimum flood levels; the lake displacement wave height; the extent of the flooded area; and the travel time from Lake 513 to the confluence with the Santa River. This demonstrates that the model offers a reliable reconstruction of the basic hydrological characteristics of the GLOF. It provides important information about the flood intensity and significantly improves our ability to model future flood scenarios along both the studied river and within neighbouring catchments. The flood hazard, defined by the flood depth during peak discharge, shows that the majority of the damaged infrastructure (houses, bridges, and a drinking water treatment plant) was only subjected to low or medium flood intensities (defined by a maximum water depth of less than 2 m). These low flood intensities help to explain why the flooding caused comparatively minor damage despite the significant public attention it attracted. 相似文献
15.
Victor R. Baker 《Environmental Geology》1976,1(5):261-281
The “upstream” approach to flood hazard evaluation involves the estimation of hydrologic response in small drainage basins.
This study demonstrates the application of geomorphology to such studies in a region of unusually intense flooding in central
Texas. One approach to flood hazard evaluation in this area is a parametric model relating flood hydrograph characteristics
to quantitative geomorphic properties of the drainage basins. A preliminary model uses multiple regression techniques to predict
potential peak flood discharge from basin magnitude, drainage density, and ruggedness number. After mapping small catchment
networks (4 to 20 km2) from remote sensing imagery, input data for the model are generated by network digitization and analysis by a computer-assisted
routine of watershed analysis.
The study evaluated the network resolution capabilities of the following data formats: (1) large-scale (1:24,000) topographic
maps, employing Strahler's “method of v's”, (2) low altitude black-and-white aerial photography (1:13,000 and 1:20,000 scales),
(3) NASA-generated aerial infrared photography at scales ranging from 1:48,000 to 1:123,000, and (4) Skylab Earth Resources
Experiment Package S-190A and S-190B sensors (1:750,000 and 1:500,000 respectively). Measured as the number of first order
streams or as the total channel length identified in small drainage areas, resolution is strongly dependent on basin relief.
High-density basins on the Edwards Plateau were poorly depicted on orbital imagery. However, the orbital network definition
of low-relief basins on the inner Texas Coastal Plain is nearly as accurate as results from large-scale topographic maps.
Geomorphic methods are also useful for flood hazard zonation in “downstream” flood plain areas. Studies of the Colorado River
valley near Austin, Texas, easily distinguished infrequent (100- to 500-year recurrence interval), intermediate (10- to 30-year),
and frequent (1- to 4-year) hazard zones. These mapping techniques are especially applicable to the rapid regional evaluation
of flood hazards in areas for which there is a lack of time and money to generate more accurate engineering-hydraulic flood
hazard maps. 相似文献
16.
This article explores the impacts of floods on the economy, environment, and society and tries to clarify the rural community’s
coping mechanism to flood disasters in Central Viet Nam. It focuses on the social aspects of flood risk perception that shapes
the responses to floods. The research findings revealed that flooding is an essential element for a coastal population, whose
livelihood depend on productive functions of cyclical floods. The findings also revealed that floods, causing losses and damages,
often inhibited economic development. The surveyed communities appeared to have evolved coping mechanisms to reduce the negative
impacts of the floods, yet these coping mechanisms are under pressure due to environmental degradation. Integrated flood risk
management is considered as a suitable paradigm for coping with flood disasters.
相似文献
| Phong TranEmail: |
17.
新疆洪灾时间序列突变及其气候原因分析 总被引：6，自引：2，他引：4
利用统计方法对新疆农田洪灾成灾面积和洪灾次数时间序列进行了非参数突变检验, 发现新疆农田洪灾成灾面积和洪灾次数时间序列在1980年代中后期发生了明显的突变.突变现象在洪灾直接经济损失上也有明显表现, 主要表现为洪灾直接经济损失在1980年代中后期出现了明显的差异, 即1980年代中后期以前损失较低, 之后急剧增大.在分析了洪灾序列和降水序列的相关关系的基础上, 认为1980年代中后期新疆洪灾损失突变的主要原因之一是此时期新疆气候发生了由干到湿的转折. 相似文献
18.
Shafi Noor ISLAM 《Frontiers of Earth Science》2010,4(4):438-448
Wetlands constitute a part of human heritage. It has played a significant role in the development of human culture and society.
More over it contains very rich components of biodiversity of local, national, and regional significance. They also provide
habitat for a variety of resident and migratory waterfowl, a significant number of endangered species, and a large number
of commercially important species. Mangrove wetlands are unique environments of floral-faunal assemblages, providing a complex
detritus-based food-web for a number of marine and brackish water organisms. Wetlands in Bangladesh have great importance
for the country’s economic, industrial, ecological, socioeconomic, and cultural aspects. There are five types of wetlands
available in Bangladesh, such as saltwater wetlands, freshwater wetlands, palustrine wetlands, lacustrine wetlands, and manmade
wetlands. There are 43 designated wetlands, and some are under threat from indiscriminate utilization, encroachments and reclamation,
urbanization and drawbacks from agricultural development, and flood control. Almost 50% of the country’s people are directly
dependent on wetlands resources. The vast majority of the poor people in the wetlands areas are dependent on wetlands resources
for their nourishment. Wetlands have potential and have been recognized as a driving force for biodiversity conservation and
rural socioeconomic improvement. Smart-use of wetlands can solve the ecosystems problems in the floodplain areas. A comprehensive
analysis of the various issues leading to wetlands degradation is made in this study. The country needs an adequate interdisciplinary
policy and political will to implement it for sustainable management and protection of wetlands and ecologically sensitive
ecosystems in Bangladesh. Therefore, a reliable data bank is provided in this study to enhance the conservation measures initiated
by the Government. 相似文献
19.
Flooding is a serious problem in Jakarta, and detailed estimation of flood damage is necessary to design optimal flood management strategies. This study aims to estimate flood damage in a densely populated area in Jakarta by means of a survey, to develop the relationship between flood characteristics and flood damage, and to compare the damage estimates from the survey with the damage estimates obtained by a flood damage model for Jakarta, i.e. the damage scanner model. We collected data on economic losses of the January 2013 flood in a survey of flood-affected households and business units in Pesanggrahan River. The actual flood damage in the survey area is US$ 0.5 million for the residential sector and US$ 0.7 million for the business sector. The flood damage for a similar event in the same area based on the damage scanner model is estimated to be US$ 1.3 million for the residential sector and US$ 9.2 million for the business sector. The flood damage estimates obtained by the survey approach are lower compared to the damage scanner approach due to different ways in obtaining flood damage data and in defining the maximum flood damage per object, the different spatial levels of analysis, and uncertainties in constructing the flood damage curves that were applied in the damage scanner model. 相似文献
20.
防洪效益评估对防洪工程投资决策与减灾对策制定具有重要意义。建立集成了与太湖流域防洪效益评估相关的系列模型和方法,包括含降雨产流与平原净雨计算的水文分析方法、由河网水动力学模型和平原区域洪水分析模型组成的大尺度水力学模型、综合流域社会经济和淹没因素的洪灾损失评估模型。模拟了太湖流域遇特大洪水的灾害损失,开展了不同防洪工程应对流域性特大洪水减灾效益的预测分析。结果表明:1999年型200年一遇降雨将会给太湖流域造成高达568.29亿元的直接经济损失,外排动力增强30%至100%的防洪效益介于26.69亿元到45.70亿元之间,新建圩区、太浦河拓宽的防洪效益依次减小,而圩区泵排能力增加30%的防洪效益仅为0.65亿元。基于研究成果提出了增设外排泵站、加强圩区科学调度、通过保险分担风险等应对特大洪水的对策措施建议,为太湖流域特大洪水的防治提供支撑和参考。 相似文献