Use of LSPIV in assessing urban flash flood vulnerability

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.     

Household vulnerability and resilience in flood hazards from disaster-prone areas of Punjab,Pakistan

Natural Hazards - An environmental variation has caused Pakistan an alarming portrait of vulnerability in flood disasters. The government has focused on a number of realistic actions, heartening...     

Mapping exposure to snow in a developing African context: implications for human and livestock vulnerability in Lesotho

Alpine cryospheric hazards are becoming increasingly prominent under current global/regional climate change scenarios and receiving wide scientific coverage from, in particular, northern hemisphere mountain regions associated with glaciers, permafrost, and extensive seasonal snow cover. However, there is a general paucity of knowledge and attention on cryospheric hazards associated with mountain environments only occasionally/rarely impacted by heavy seasonal snowfalls or severe frost events, particularly those in developing and southern hemisphere regions. Prolonged snow cover in the Lesotho Highlands sometimes carries the consequence of human and livestock deaths owing to isolation and exposure in this developing region. We use daily Moderate Resolution Imaging Spectroradiometer snow cover images for the period 2003–2010, to establish the frequency, extent, and timing of snowfalls across Lesotho. In addition, a digital shape file containing the location, name, and district attributes of 2,016 villages across Lesotho was used to assist in the construction of a village exposure to snow index. A ranking system was applied to each village according to the seasonal duration of snow cover, and the accessibility and proximity to the nearest road. Snowfalls occur on average between 1 and 8 times per annum, with village exposure to snow (potential vulnerability) being generally low, particularly for the lowlands and Senqu River Valley. However, the study identifies that some high-altitude (>2,500 m) villages such as Thoteng, Letseng-la-Terae, and Mabalane are, on occasion, highly exposed to prolonged snow cover, and particularly so during the mid-snow season of July/August. We demonstrate the importance of applying spatiotemporal assessments on infrequent snow occurrences (which carry associated hazards) in developing mountain regions such as Lesotho, with implications to reduce livelihood risks through improved disaster preparedness and a well-informed, focused emergency response.     

Chronicle of a forecast flood: exposure and vulnerability on the south-east coast of Spain

Natural Hazards - In recent years, floods have become one of the natural hazards that generate the greatest economic and human losses on the planet. As is well known, torrential rainfall events are...     

Spatial heterogeneity of local flood vulnerability indicators within flood-prone areas in Taiwan

Global environmental change is bringing extreme precipitation, and the combination of natural and artificial impacts are resulting in serious floods on the west coast of Taiwan. Disparity in social, economic and infrastructure resources contributes to spatial variation in the vulnerability to flood disaster. Owing to the high frequency of torrential rain and serious land subsidence in the study area, this paper attempts to categorize vulnerability indicators under varied assumptions of spatial homogeneity and spatial heterogeneity. The results show that the spatial heterogeneity indeed affects the distribution of flood vulnerability indicators. The core value of this article is that it measures the improvement from using geographically weighted statistics rather than traditional statistics. For the flood vulnerability discussion, this paper demonstrates the importance of considering spatial heterogeneity when allocating resources against floods.     

Tsunami impact assessment: development of vulnerability matrix for critical infrastructure and application to Christchurch,New Zealand

Natural Hazards - Tsunamis can have severe impacts on society. In addition to casualties and damage to buildings, they can also damage and disrupt critical infrastructure. To support effective risk...     

Assessing multifaceted vulnerability and resilience in order to design risk-mitigation strategies

Vulnerability studies have evolved significantly in recent decades. Although not overly theoretical compared with some other fields of science, some important conceptual progress has been made. At the practical level, vulnerability indicators have been used either at a generic level or for particular hazard contexts. However, these indicators are often predictably too narrow in their coverage of aspects of vulnerability. An important need remains to produce more conceptually informed vulnerability indicators or parameters and more satisfactory operational tools to assess weaknesses and resilience in coping with natural risks. In this paper, we present the methodology developed in the context of a recently concluded EU funded project, ENSURE (Enhancing resilience of communities and territories facing natural and na-tech hazards). The resulting vulnerability and resilience assessment framework tool adopts a systemic approach embedding and integrating as much as possible the multifaceted and articulated nature of concepts such as vulnerability and resilience. The tool guides evaluators towards a comprehensive and context-related understanding of strengths and fragilities of a given territory and community with respect to natural extremes. In this paper, both the framework tool and its application to Sondrio in Italy, which is exposed to flash floods, are presented and discussed. The merits and demerits of the new tool are discussed, and the results of the application to Sondrio indicate where data are currently missing, suggesting the kind of data, which will need to be gathered in future to achieve more complete assessments. The results also suggest vulnerability reduction policies and actions and further ways of revising the existing framework tool in the future.     

Lessons learnt from Typhoons Fitow and In-Fa: implications for improving urban flood resilience in Asian Coastal Cities

Natural Hazards - Frequent typhoons significantly affect many coastal cities via intensive rainstorms, tidal surges and strong wind. Natural factors induced by human disturbance such as climate...     

An approach for measuring social vulnerability in context: The case of flood hazards in Muzarabani district,Zimbabwe

Understanding the complexity of vulnerability to disasters, including those triggered by floods, droughts and epidemics is at the heart of disaster risk reduction. Despite its importance in disaster risk reduction, there remains a paucity of approaches that contribute to our understanding of social vulnerability that is hidden in dynamic contextual conditions. The study demonstrates an accessible means to assessing the spatial variation of social vulnerability to flood hazards and related for the context of Muzarabani district in northeast Zimbabwe. The study facilitated local identification with residents of variables contributing to social vulnerability and used the principal component analysis (PCA) technique to develop a social vulnerability index (SoVI). Using ArcMap10.2 geographic information systems (GIS) tool, the study mapped composite SoVI at the ward level. The results showed that Muzarabani district is socially vulnerable to hazards. The social vulnerability is influenced by a variety of economic, social and institutional factors that vary across the wards. Quantifying and visualising social vulnerability in Muzarabani provides useful information for decision makers to support disaster preparedness and mitigation programmes. The approach shows how spatially distributed multivariate vulnerability, as grounded in interpretations at local level, can be quantitatively derived for contexts such as those of Muzarabani. The study findings can inform disaster risk reduction communities and cognate disciplines on quantitative assessments for managing hazard vulnerability where these have hitherto not been developed.     

Spatial aspects of building and population exposure data and their implications for global earthquake exposure modeling

This paper discusses spatial aspects of the global exposure dataset and mapping needs for earthquake risk assessment. We discuss this in the context of development of a Global Exposure Database for the Global Earthquake Model (GED4GEM), which requires compilation of a multi-scale inventory of assets at risk, for example, buildings, populations, and economic exposure. After defining the relevant spatial and geographic scales of interest, different procedures are proposed to disaggregate coarse-resolution data, to map them, and if necessary to infer missing data by using proxies. We discuss the advantages and limitations of these methodologies and detail the potentials of utilizing remote-sensing data. The latter is used especially to homogenize an existing coarser dataset and, where possible, replace it with detailed information extracted from remote sensing using the built-up indicators for different environments. Present research shows that the spatial aspects of earthquake risk computation are tightly connected with the availability of datasets of the resolution necessary for producing sufficiently detailed exposure. The global exposure database designed by the GED4GEM project is able to manage datasets and queries of multiple spatial scales.     

Hydrodynamic modelling and vulnerability analysis to assess flood risk in a dense Indian city using geospatial techniques

Natural Hazards - Urban flooding and waterlogging are causing menace in many cities around the world from the perspective of day-to-day functioning, health and hygiene, communication, and the...     

Participatory modelling of vulnerability and adaptive capacity in flood risk management

Being part of the EU-project NeWater on adaptive water resources management, the Ukrainian Tisa river basin is presented as an example for a participatory study dealing with flood risk, vulnerability and adaptive capacity. The Tisa valley is regularly and increasingly faced with hazardous floods at very limited local budgets and high poverty rates. In order to make flood risk management more resilient and better adapted to climate change, scientists and stakeholders applied a set of qualitative and quantitative modelling approaches to characterise prevailing flood risk management, to discover respective vulnerabilities and to identify barriers and options of adaptive capacity. The former were found in the defensive mentality paradigm and the inert and hierarchical structure of present institutions, the latter in, firstly, an enormous potential to link the knowledge of different stakeholders in the region, secondly, a better integration of the individual flood preparedness of households and thirdly, the active involvement of the Church as institution in local flood risk management.     

Vulnerability,resilience and development discourses in context of climate change

The paper discusses how the current climate change debate influences the way in which development is conceptualised, negotiated and implemented. The objective of the article is to explore some of the underlying controversies that characterise development discourses in the context of climate change. Adaptation to climate change goes along with a significant shift in discourses used to deal with what is normally called development. This is reflected in shifting research interests and perspectives, from vulnerability studies to resilience thinking. However, the paper argues, this shift is problematic for the normative contents of development and especially for a pro-poor and grass roots perspective.     

Organizing social resilience in the context of natural hazards: a research note

Organizational scholars increasingly use the term “resilience” to analyze options of dealing with uncertain context conditions. What do these scholars have to offer to researchers in the field of natural hazards? This research note makes three suggestions. First, the research note frames social resilience—in contrast to a rigid response to radical change—as a process of broadening information-based activities, loosening formal controls, and using slack resources of organizational members. Second, the research note argues to leave the meaning of social resilience undefined at the outset of a research project with the aim of building theory about resilience. It is expected that a useful definition emerges in empirical research. Third, organizational studies highlight specific social structures and processes of social resilience, for instance, small groups of individuals in organizational and interorganizational contexts. Organizing becomes a crucial factor for dealing with natural hazards.