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1.
The recurrent flooding during monsoon and subsequent waterlogging in the northern Bihar plains and the magnitude of losses
due to these hazards indicate the continuing vulnerability of the region to flood and waterlogging. Management of floods and
waterlogging hazards in highly flood-prone regions of India, including Bihar state has been largely response oriented with
little or no attention to mitigation and preparedness. This paper presents a method for spatial, Geographic Information Systems-based
assessment of flood and waterlogging vulnerability and risk in northern Bihar plains. Multitemporal satellite data was used
to evaluate the area statistics and dynamics of waterlogging over the period from 1975 to 2008. The flood proneness is evaluated
at district level with reference to flood inundation during a period from 1998 to 2008. Census data were used to examine the
socio-economic characteristics of the region through computation of population density, cultivators, agricultural labourers,
sex ratio, children in age group 0–6 years and literates. The geohazard map derived by combining area prone to waterlogging
and flood inundation was multiplied with socio-economic vulnerability map to derive the flood-waterlogging risk map of the
region. The result shows that flood and water-logging pose highest risk to the central districts in the northern Bihar plains
with 50.95% of the total area under high and very high risk. 相似文献
2.
以受山洪灾害影响突出的云南文山城区为研究区,从承灾体属性特征和社会承灾能力二个方面探讨了城市山洪灾害易损性分析的方法;利用高分辨率遥感卫星影像为数据源完成城市土地覆盖类型解译,在此基础上应用GIS定量分析城市山洪灾害易损性。对承灾体属性特征定量分析结果表明,文山城区50年一遇山洪淹没范围内的承灾体中城市房屋建筑的易损性最大。对易损性要素中的社会承灾能力分析认为,由于文山城区段防洪河道行洪能力低,蓄滞洪能力弱。山洪灾害的易损性仍然较高,山洪对文山城威胁形势严峻。 相似文献
3.
Since ancient times, floods occurred frequently in Huaihe River with significant casualties and economic losses. In developing measures for disaster prevention or emergency response for disaster relief, the study of social vulnerability to floods in Huaihe River Basin should be strengthened. Based on the latest socioeconomic data, the index system of social vulnerability to floods was constructed from three dimensions: population, economy, and flood prevention. Sensitive indexes were identified from the original indexes by principal component analysis, and the social vulnerability index for floods was calculated for Huaihe River Basin. The results described the characteristics of the spatial distribution. It also demonstrated that vulnerability manifests itself as a regional phenomenon, with significant changes from city to city across the Huaihe River Basin. Understanding the impacts of changes in vulnerability was crucial in developing measures to prevent floods. 相似文献
4.
Hydrological extreme events pose an imminent risk to society and economics. In this paper, various aspects of hydrological hazards in Russia are analysed at different scales of risk assessment. It is shown that the number of hydrological and meteorological hazards in Russia has been growing every year. The frequency of economic losses associated with extreme low flow in this century has increased by factor five compared to the last decade of the previous century. With regard to floods, an interesting spatial patter can be observed. On the one hand, the number of floods in the Asian part of the country has increased, whereas on the other hand, the number and intensity of floods in estuarine areas in the European part of Russia have significantly reduced since the middle of the twentieth century, especially in the 2000s. This decrease can be attributed to runoff flooding in the mouths of regulated rivers, with an effective system of flood and ice jam protection. The analysis shows that there is an 8–12-year periodicity in the number of flood occurrences and that flood surges have intensified over the last 110 years, especially on the European territory of Russia. An integrated index that accounts for flood hazards and socio-economic vulnerability was calculated for each region of Russia. A classification of flood risk was also developed, taking into account more than 20 hydrological and social–economic characteristics. Based on these characteristics, hazard and vulnerability maps for entire Russia were generated which can be used for water management and the development of future water resources plans. 相似文献
5.
在西北气候由暖干转向暖湿的过程中,新疆河流的洪水和洪灾反映明显.对新疆29条河流选取年最大洪水,统计出超标准洪水、20a一遇、50a一遇洪水的出现频次进行分析,结果显示1987年后洪水量级、洪水频次呈增加的变化趋势.通过20世纪90年代以来灾害性洪水出现的频次、灾害损失的变化比较分析,90年代以来灾害性洪水尤其是灾害性暴雨洪水和突发性洪水呈现增加的态势,1987—2000年的灾害损失与1950—1986年相比增加了30倍. 相似文献
6.
Hydrological extreme events pose an imminent risk to society and economics. In this paper, various aspects of hydrological hazards in Russia are analysed at different scales of risk assessment. It is shown that the number of hydrological and meteorological hazards in Russia has been growing every year. The frequency of economic losses associated with extreme low flow in this century has increased by factor five compared to the last decade of the previous century. With regard to floods, an interesting spatial patter can be observed. On the one hand, the number of floods in the Asian part of the country has increased, whereas on the other hand, the number and intensity of floods in estuarine areas in the European part of Russia have significantly reduced since the middle of the twentieth century, especially in the 2000s. This decrease can be attributed to runoff flooding in the mouths of regulated rivers, with an effective system of flood and ice jam protection. The analysis shows that there is an 8–12-year periodicity in the number of flood occurrences and that flood surges have intensified over the last 110 years, especially on the European territory of Russia. An integrated index that accounts for flood hazards and socio-economic vulnerability was calculated for each region of Russia. A classification of flood risk was also developed, taking into account more than 20 hydrological and social–economic characteristics. Based on these characteristics, hazard and vulnerability maps for entire Russia were generated which can be used for water management and the development of future water resources plans. 相似文献
7.
The paper presents the result of a vulnerability assessment of urban dwellers to a major flood hazard in Abeokuta, southwestern
Nigeria in July 2007. This was achieved by means of questionnaire survey administered to 248 flood area residents. Flood vulnerability
was assessed by examining exposure, susceptibility, and coping indicators in the study area. Findings of the study show that
although about 50% of respondents had experienced floods, in Abeokuta or elsewhere in the past, majority (66%) did not anticipate
a flood event of such magnitude to occur despite its location on a flood plain and, therefore, were unprepared for such hazard.
Pre-warning of the flood event was generally lacking among flood area residents as only 8% of respondents indicated pre-warning,
which was based on personal observations. Response to the flood hazard was mainly reactive for both private and public agents
as flood risk reduction measures were not in place. 相似文献
8.
The risk analysis of flood and drought disasters and the study of their influencing factors enhance our understanding of the temporal and spatial variation law of disasters and help identify the main factors affecting disasters. This paper uses the provincial administrative region of China as the research area. The proportion of the disaster area represents the degree of the disaster. The statistical distribution of the proportions was optimized from 10 alternative distributions based on a KS test, and the disaster risk was analyzed. Thirty-five indicators were selected from nature, agriculture and the social economy as alternative factors. The main factors affecting flood and drought disasters were selected by Pearson, Spearman and Kendall correlation coefficient test. The results demonstrated that the distribution of floods and drought is right-skewed, and the gamma distribution is the best statistical distribution for fitting disasters. In terms of time, the risk of flood and drought disasters in all regions showed a downward trend. Economic development and the enhancement of the ability to resist disasters were the main reasons for the change in disasters. Spatially, the areas with high drought risk were mainly distributed in Northeast and North China, and the areas with high flood risk were mainly distributed in the south, especially in Hubei, Hunan, Jiangxi and Anhui. The distribution of floods and drought disasters was consistent with the distribution characteristics of precipitation and water resources in China. Among the natural factors, precipitation was the main factor causing changes in floods and drought disasters. Among the agricultural and socioeconomic factors, the indicators reflecting the disaster resistance ability and regional economic development level were closely related to flood and drought disasters. The research results have reference significance for disaster classification, disaster formation mechanisms and flood and drought resistance. 相似文献
9.
The probability of the occurrence of urban flash floods has increased appreciably in recent years. Scientists have published various articles related to the estimation of the vulnerability of people and vehicles in urban areas resulting from flash floods. However, most published works are based on research performed using numerical models and laboratory experiments. This paper presents a novel approach that combines the implementation of image velocimetry technique (large-scale particle image velocimetry—LSPIV) using a flash flood video recorded by the public locally and the estimation of the vulnerability of people and vehicles to high water velocities in urban areas. A numerical one‐dimensional hydrodynamic model has also been used in this approach for water velocity characterization. The results presented in this paper correspond to a flash flood resulting on November 29, 2012, in the city of Asunción in Paraguay. During this flash flood, people and vehicles were observed being carried away because of high water velocities. Various sequences of the recorded flash flood video were characterized using LSPIV. The results obtained in this work validate the existing vulnerability criterion based on the effect of the flash flood and resulting high water velocities on people and vehicles. 相似文献
10.
China suffers frequent and severe floods. A lot of studies have been done in the field of flood disaster, including flood vulnerability assessment. This paper develops assessment models of multidimensional flood vulnerability based on the data envelopment analysis method and identifies multidimensional flood vulnerability??population, death, agriculture and economy??at the provincial scale in China using flood damage data and socioeconomic statistical data from 2001 to 2010. Based on the characteristics of multidimensional flood vulnerability of each province, some suggestions for flood prevention and mitigation are suggested. The assessment models of multidimensional flood vulnerability are simple and can be used for vulnerability analysis of natural disaster at regional or national levels. The assessment of multidimensional flood vulnerability can provide multifaceted information that contributes to a deeper understanding of the flood vulnerability and provides a scientific base for the policy making and implementation of flood prevention and mitigation designs. 相似文献
11.
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
12.
In the last decades, floods have increased in frequency all over the world due to diverse phenomena such as climate change, extended urbanization, land use, etc. Their social, cultural, economic and environmental impacts have also grown significantly, highlighting the need for the development of further studies and improved methods to manage and mitigate flood risk, mainly in urban areas. Historic sites need particular attention in this field, not only because the high and irreplaceable cultural value of these areas, but also taking into account that the constructive typologies that they host are particularly vulnerable to natural hazards. In consequence of that, the analysis of the phenomena, the evaluation of their consequences and the adoption of adequate mitigation and preparedness measures are presently a fundamental societal challenge. Having this in mind, the present paper aims at proposing an innovative methodology focused on the assessment of flood vulnerability in historic sites through the evaluation of a set of exposure and sensitivity indicators. From the analysis of these indicators, it is possible to obtain a Flood Vulnerability Index capable of measuring the spread of flood vulnerability over an extended area. The historic centre of Guimarães, in Portugal, declared by UNESCO as a World Heritage Site in 2001, is used here as a pilot case study to apply and discusses the preliminary version of the approach. Although some improvements are still needed, this approach can be already used to provides preliminary vulnerability scenarios and to point the way to the definition of more efficient and customized strategies for managing and mitigating flood risk in historic sites. Moreover, with further improvements and calibrations resorting to larger and more diverse data, it will be possible to reduce some of the uncertainties currently involved in the assessment process and to make its application wider and more robust. 相似文献
13.
Dire Dawa city is identified as one of the most flood-affected cities in Ethiopia. Classifying village-level flood vulnerability using flood indicators is a new approach to Dire Dawa city. Analysis of different flood vulnerability factors underpins sustainable flood risk management and the application of Flood Vulnerability Index (FVI) approach is the hub of this study. Relevant data were collected from 110 households sampled from purposely selected 10 villages found in Dire Dawa city. The flood vulnerability index was used to compare, classify and rank villages in terms of their flood vulnerability levels. For this purpose, 24 sets of indicators which are strongly affecting the levels of flood vulnerability were assessed from social, economic and physical perspectives. The FVI of each village was computed with unequal method of weighting indicators. The findings of the study revealed that Dire Dawa city villages were experiencing varying levels of flood vulnerability. Accordingly, villages 05, 06, 07 and 09 were identified with high flood vulnerability level while villages 03, 04 and 08 and villages 01, 02 and extension village were identified with medium and low level of vulnerability, respectively. Interestingly, the findings of the study confirmed that social factors contributed much for flood vulnerability in Dire Dawa city. Hence, future urban flood risk planning and management endeavors in the city of Dire Dawa must be underpinned by proper utilization of the flood vulnerability map developed addressing social vulnerability component through both structural and non-structural urban flood risk management measures. 相似文献
14.
Every year floods cause enormous damage all over the world. This study investigates loss of human life statistics for different types of floods and different regions on a global scale. The OFDA/CRED Database contains data on international disasters and is maintained by the Centre for Research on the Epidemiology of Disasters in Brussels (CRED) in cooperation with United States Office for Foreign Disaster Assistance (OFDA). Information from this source on a large number of flood events, which occurred between January 1975 and June 2002, is evaluated with respect to flood location and flood type. Due to the limited availability of information on coastal flood events, the scope of this study is limited to three types of freshwater flooding: river floods, flash floods and drainage problems. First, the development of loss of life statistics over time is discussed. Second, the dataset is analysed by region, by flood type and by the combination of type and region. The study shows that flash floods result in the highest average mortality per event (the number of fatalities divided by the number of affected persons). A cross analysis by flood type and location shows that average mortality is relatively constant for the different types over various continents, while the magnitude of the impacts (numbers of killed) and affected for a certain type varies between the different continents. On a worldwide scale Asian river floods are most significant in terms of number of persons killed and affected. Finally, a comparison with figures for other types of natural disasters shows that floods are the most significant disaster type in terms of the number of persons affected. 相似文献
15.
This paper examines flood frequencies in three coastal sectors of Britain and analyses the associated storm tracks and their principal pathways. The results indicate that the east coast of Britain has suffered most floods over the last 200 years. The frequencies of flood incidents in the south and southwest coast of Britain have increased, particularly during the 20th century, whereas on the west coast flood frequencies have declined. Three distinctive pathways of storm track are identified, related to flood incidents in each coastal sector. A southern pathway in a corridor along the 55° N parallel is associated with flood incidents recorded on the south and southwest coast, whilst storms that are associated with floods on the west coast concentrate along the 60° N parallel. The relationship between the frequencies of floods and climatic variations needs to be explored further. However, the development of coastal settlements has certainly increased vulnerability, and hence the risk of flood disasters. 相似文献
16.
受洪水补给来源和阿尔泰山山势影响,阿勒泰地区洪水发生时间比新疆其他以高山永久积雪和冰川融水补给为主的河流偏早。因此,从认识洪水特性、预防洪水灾害角度出发,对阿勒泰地区洪水发生机制、时空分布和变化特点进行分析研究是很有必要的。利用阿勒泰地区各主要河流1960~2011年历年洪峰、冬季和汛期降水、气温和700hPa高空温度资料,对洪水发生机制、时空分布和变化特点进行分析。结果表明:(1)本区洪水类型有融雪型洪水、融雪与降水混合型洪水和暴雨型洪水;(2)洪水与冬季积雪和汛期气温、降雨有关;(3)汛期过程相对短,主汛期发生时间以5月下旬至6月中旬期为主;(4)洪水挟沙能力强,汛期含沙量占年含沙量近90%;(5)暴雨洪水多发生于阿勒泰地区的中东部区域河流上;(6)全区洪水具有同步性,洪水年际变化相对小。 相似文献
17.
利用社会经济统计数据和水文气象资料,探讨城市化背景下北京城市洪涝特征、形成机制及影响因素。近50年来城市内涝逐渐成为北京洪涝灾害的主要类型,随着城市化迅猛发展,城市内涝积水点数量在时间上表现为显著增加趋势,在空间上呈现出由内环逐步向外环扩张趋势,与城市化发展空间格局关系密切。从水循环的角度分析城市洪涝形成机制,指出区域气候变化和城市化发展改变了城市降水格局,汛期降水量和极端降水事件呈现下降趋势,但城区短历时强降水事件呈现增加态势;城市化发展改变了区域下垫面条件、城市流域产汇流特性和城市排水格局,进而影响了区域水循环过程和水量分配,在一定程度上增加了城市洪涝灾害风险;同时城市基础设施建设水平不足、排水排涝标准偏低、应急管理能力不足等因素,导致城市洪涝发生风险增加,降低了城市洪涝综合应对能力。 相似文献
18.
Urban pluvial flash floods have become a matter of widespread concern, as they severely impact people’s lives in urban areas. Hydrological and hydraulic models have been widely used for urban flood management and urban planning. Traditionally, to reduce the complexity of urban flood modelling and simulations, simplification or generalization methods have been used; for example, some models focus on the simulation of overland water flow, and some models focus on the simulation of the water flow in sewer systems. However, the water flow of urban floods includes both overland flow and sewer system flow. The overland flow processes are impacted by many different geographical features in what is an extremely spatially heterogeneous environment. Therefore, this article is based on two widely used models (SWMM and ANUGA) that are coupled to develop a bi-directional method of simulating water flow processes in urban areas. The open source overland flow model uses the unstructured triangular as the spatial discretization scheme. The unstructured triangular-based hydraulic model can be better used to capture the spatial heterogeneity of the urban surfaces. So, the unstructured triangular-based model is an essential condition for heterogeneous feature-based urban flood simulation. The experiments indicate that the proposed coupled model in this article can accurately depict surface waterlogged areas and that the heterogeneous feature-based urban flood model can be used to determine different types of urban flow processes. 相似文献
20.
Regional flood frequency analysis (RFFA) is often used in hydrology to estimate flood quantiles when there is a limitation
of at-site recorded flood data. One of the commonly used RFFA methods is the index flood method, which is based on the assumptions
that a region satisfies criterion of simple scaling and it can be treated homogeneous. Another RFFA method is quantile regression
technique where prediction equations are developed for flood quantiles of interest as function of catchment characteristics.
In this paper, the scaling property of regional floods in New South Wales (NSW) State in Australia is investigated. The results
indicate that the annual maximum floods in NSW satisfy a simple scaling assumption. The application of a heterogeneity test,
however, reveals that NSW flood data set does not satisfy the criteria for a homogeneous region. Finally, a set of prediction
equations are developed for NSW using quantile regression technique; an independent test shows that these equations can provide
reasonably accurate design flood estimates with a median relative error of about 27%. 相似文献
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