A multi-dimensional assessment of urban vulnerability to climate change in Sub-Saharan Africa

In this paper, we develop and apply a multi-dimensional vulnerability assessment framework for understanding the impacts of climate change-induced hazards in Sub-Saharan African cities. The research was carried out within the European/African FP7 project CLimate change and Urban Vulnerability in Africa, which investigated climate change-induced risks, assessed vulnerability and proposed policy initiatives in five African cities. Dar es Salaam (Tanzania) was used as a main case with a particular focus on urban flooding. The multi-dimensional assessment covered the physical, institutional, attitudinal and asset factors influencing urban vulnerability. Multiple methods were applied to cover the full range of vulnerabilities and to identify potential response strategies, including: model-based forecasts, spatial analyses, document studies, interviews and stakeholder workshops. We demonstrate the potential of the approach to assessing several dimensions of vulnerability and illustrate the complexity of urban vulnerability at different scales: households (e.g., lacking assets); communities (e.g., situated in low-lying areas, lacking urban services and green areas); and entire cities (e.g., facing encroachment on green and flood-prone land). Scenario modeling suggests that vulnerability will continue to increase strongly due to the expected loss of agricultural land at the urban fringes and loss of green space within the city. However, weak institutional commitment and capacity limit the potential for strategic coordination and action. To better adapt to urban flooding and thereby reduce vulnerability and build resilience, we suggest working across dimensions and scales, integrating climate change issues in city-level plans and strategies and enabling local actions to initiate a ‘learning-by-doing’ process of adaptation.

     

A multi-dimensional assessment of urban vulnerability to climate change in Sub-Saharan Africa

In this paper, we develop and apply a multi-dimensional vulnerability assessment framework for understanding the impacts of climate change-induced hazards in Sub-Saharan African cities. The research was carried out within the European/African FP7 project CLimate change and Urban Vulnerability in Africa, which investigated climate change-induced risks, assessed vulnerability and proposed policy initiatives in five African cities. Dar es Salaam (Tanzania) was used as a main case with a particular focus on urban flooding. The multi-dimensional assessment covered the physical, institutional, attitudinal and asset factors influencing urban vulnerability. Multiple methods were applied to cover the full range of vulnerabilities and to identify potential response strategies, including: model-based forecasts, spatial analyses, document studies, interviews and stakeholder workshops. We demonstrate the potential of the approach to assessing several dimensions of vulnerability and illustrate the complexity of urban vulnerability at different scales: households (e.g., lacking assets); communities (e.g., situated in low-lying areas, lacking urban services and green areas); and entire cities (e.g., facing encroachment on green and flood-prone land). Scenario modeling suggests that vulnerability will continue to increase strongly due to the expected loss of agricultural land at the urban fringes and loss of green space within the city. However, weak institutional commitment and capacity limit the potential for strategic coordination and action. To better adapt to urban flooding and thereby reduce vulnerability and build resilience, we suggest working across dimensions and scales, integrating climate change issues in city-level plans and strategies and enabling local actions to initiate a ‘learning-by-doing’ process of adaptation.     

Social vulnerability assessment to seismic risk using multicriteria analysis: the case study of Vila Franca do Campo (S?o Miguel Island, Azores, Portugal)

The increase in the frequency and magnitude of disasters triggered by earthquakes in different regions of the Earth is a major challenge to contemporary societies. The awareness that disasters and risk are processes structured on spatial?Ctemporal interactions maintained at the social-ecological system between the natural hazards and the vulnerabilities of socioeconomic, political and physical nature becomes utterly important in the increase of social systems?? resilience. Thus, the assessment of social vulnerability plays a decisive role in understanding the factors that distinguishes individuals, households and communities, in terms of their ability to anticipate, cope with, resist to and recover from the impact of disasters triggered by natural hazards. This article presents a geographic information system (GIS)-based approach model to assess the social vulnerability to seismic risk using multicriteria analysis (MCA) techniques, in a group decision-making process. The methodology applied to the municipality of Vila Franca do Campo (S?o Miguel Island, Azores, Portugal) identified moderate social vulnerability values at the neighbourhood level and higher social vulnerability values for the built environment and demographic characteristics of the social groups. The social vulnerability patterns make a clear distinction between the older/historical urban cores and the new urban areas. In the first case, the presence of ancient buildings constructed with materials of low resistance to earthquakes coupled with a higher population density and the traits of demographic and socioeconomic frailties of the social groups, results in higher vulnerability values. This pattern is common in the historic centre of S. Miguel district, Ribeira das Taínhas, northern areas of água de Alto and western and eastern neighbourhoods of Ponta Gar?a. The new urban areas, mainly found in S. Pedro, central areas of água de Alto, S. Miguel and Ponta Gar?a districts, have lower values of social vulnerability due to changes in the built, demographic and socioeconomic environments. Results recommend the integration of social vulnerability indexes into seismic risk mitigation policies and emergency management planning.     

基于GIS多准则空间分析(SMCE)的青海省矿产资源开发地质环境脆弱性评价

青海省具有丰富的矿产资源，其可持续开发战略与规划应建立在对地质环境脆弱性评价的基础上。笔者通过分析青海省环境地质问题和地质灾害发育的基本规律，建立了青海省未来矿产资源开发的地质环境脆弱性评价的框架。提出了地质环境脆弱性评价的基本准则和地质评价指标。在荷兰国际地球科学测量与观测学院（ITC）开发的GIS软件——ILWIS环境下，利用其新开发的空间分析功能的SMCE模块，对青海省的地质环境脆弱性进行了评价。结果表明，具有矿产资源远景开发的地区地质环境比较脆弱，对未来的矿产资源开发有着较大的制约作用。     

Integrated seismic hazard evaluation and disaster management approach for Turkey

A significant proportion of the urban areas in Turkey is subject to high seismic risk. An important step for seismic risk mitigation is to define the hazard and damage after an earthquake. This paper proposes an integrated seismic hazard assessment and disaster management processes for Turkey. The proposed methodology utilizes information technologies in its seismic assessment component that provides fast results for assessment. First, image process methodology by using satellite images was implemented in the seismic assessment process for fast evaluation right after an earthquake. Second, the seismic assessment process was integrated with disaster management process. As a result, through integrated seismic hazard evaluation and disaster management procedure, an effective, fast and dependable estimation of loss for Turkey was planned.     

Enhanced groundwater vulnerability assessment in geological homogeneous areas: a case study from the Argentine Pampas

The southeast area of the Argentine Pampas is characterized by the presence of an unconfined aquifer in a wide plain. A methodology is proposed that deals with the aquifer vulnerability where the homogeneity of the hydrogeological variables used by traditional methods (in this case, DRASTIC-P) causes vulnerability maps to show more than 80% of the territory under the same class. This absence of discrimination renders vulnerability maps of little use to decision-makers. In addition, the proposed methodology avoids the traditional vague classification (high, low, and moderate vulnerability) which is highly dependent on subjectivity in its association of each class with hydrogeological considerations. That traditional vulnerability assessment methodology was adapted using a geographic information system to reclassify classes, based on the Natural Breaks (Jenks) method. The pixel-to-pixel comparison between the result obtained by the DRASTIC-P and the reclassified classes generates the so-called operational vulnerability index (OVI), which shows four classes, associating each with different hydrogeological requirements to make decisions.     

城市地下水脆弱性评价方法及应用

地下水脆弱性评价是合理开发利用和保护地下水的基础.以国内外广泛应用的DRASTIC模型为基础,结合我国华北平原沉降带冲洪积含水层水文地质特征,提出了一种适用于层状含水层水文地质条件的城市地下水脆弱性评价模型--DRAMIP模型,并根据廊坊市的实际状况,对廊坊市浅层地下水进行了脆弱性评价,利用GIS技术生成了廊坊市浅层地下水脆弱性分布图.     

Methodology for the analysis of causes of drought vulnerability on the River Basin scale

The concept of vulnerability has emerged in recent decades as a key concept for the research on drought risk as well as in the implementation of mitigation strategies of drought risk. The context within which this concept emerges is one of scientific consensus: the research community agrees that we are witnessing a paradigm shift in water management policies, within a broader framework of changes in the relationship between humans and nature. In this context, vulnerability studies must become an instrument for the assessment and mitigation of risk. Based on the proposals put forward by the IPCC concerning the components of vulnerability (exposure, sensitivity and adaptive capacity), this paper proposes a methodology for the evaluation and analysis of drought vulnerability on the river basin scale. The methodology results in the calculation of a Drought Vulnerability Index (DVI) and the use of different techniques for the interpretation of results.     

Vulnerability to ground deformation phenomena in the city of Tuzla (BiH): a GIS and multicriteria approach

Ground deformation phenomena affecting the town of Tuzla (Bosnia Herzegovina), as consequence of underground salt deposits exploitation, have been surveyed since 60?years ago. The growing of cavities beneath the town and successive surface deformations have induced several hazard factors such as ground subsidence, deep and shallow fracturing and intense groundwater table oscillations. Fortunately, this processes had no catastrophic consequences such as sinkholes developing. Previous studies analyzed the historical database of topographic and piezometric data and highlighted a cumulative subsidence rate up to 12 meters over a period spanning from the 1956 to the 2003. Fractures arose as obvious result of ground deformation and caused damages and demolitions to thousands of buildings, with almost 15,000 people evacuated. Nowadays, in order to diminish the deformation processes, a strong reduction in brine withdrawal has been introduced by the local authorities. This caused an uplift of the water table which actually makes the spatial pattern of deformation more complex. In fact, in the most urbanized area, the sinking phenomena are now turning into uplift displacements. The presence of such a hazard required an urban vulnerability assessment able to support local authorities in the forthcoming planning procedure. The vulnerability assessment of urban elements over a wide area, potentially affected by deformation phenomena, has been accomplished by an integration between GIS solutions and a multicriteria approach based on ELECTRE-TRI methodology. The vulnerability procedure is able to define a discrete map where the 50?×?50?m width elementary cells report the most vulnerable parts of the town. In particular, the ELECTRE-TRI methodology is used to combine each vulnerable urban element with the others, expressed as vector data in a geographical dataset. The multicriteria approach is performed outside the GIS environment by the ELECTRE-TRI 2.0 package and requires a preliminary rasterization of the used dataset.     

Methodology and its application for community-scale evacuation planning against earthquake disaster

In urban area, popular and property is accumulated in a small area, potential risk of earthquake disaster in urban community is great. Pre-disaster emergency evacuation zoning has become a significant topic of disaster prevention and mitigation research. Based on the present layout of evacuation facilities and shelters as well as the evacuation demands in urban communities, a systematical methodology for occupant evacuation against earthquakes on community scale was developed by employing spatial analysis techniques of Geographical Information System (GIS). The methodology included the following aspects: the distribution analysis of emergency evacuation demands, the calculation of shelter space accessibility, and the optimization of evacuation destinations. This methodology was applied to Lujiazui Street in Pudong, a new district located in Shanghai, China. It was found that the proposed methodology could be used to formulate pre-event planning for earthquake disaster prevention and mitigation on a community scale, especially for organizing a rapid and smooth evacuation and optimizing the location allocation of shelters.     

Implementation of an integrated vulnerability and risk assessment model

An integrated vulnerability and risk assessment model (IVR) is proposed. The proposed model is a composite index that assesses the relationships among four critical components, namely exposure, hazard, vulnerability and capacities and measures, and how these can be used to illustrate the integrated risk and vulnerability situation of an area. These factors are assessed using individual variables. Fifty-four variables, objectively decided upon, were used to measure the contribution of each component factor. The general characteristics of vulnerability, risk, exposure and capacities and measures are well known; however, the relative importance of each variable and their inter-relatedness, in measuring risk and vulnerabilities, as demonstrated by the IVR; and how these in turn affect the impacts of natural hazards, are still debatable. The IVR though provides a valid, reliable and sensitive tool, which can be used to further explore these relationships. Through robust testing and application, subjectivity in the selection of variables can be reduced. Moreover, through the establishment of a database for data collection and storage, objectivity (reliability) can be achieved as well as, availability of the requisite data inputs. The sensitivity of the model allows for the quick identification of strategic action, which will ultimately lead to hazard loss reduction. The values yielded for each component factor can help decision-makers in the allocation of scarce developmental funds as well as identify trends in levels of risk, vulnerability, exposures and capacities and measures as well as determine areas where mitigation strategies are needed most.     

Integration of inland and coastal storms for flood hazard assessment using a distributed hydrologic model

Due to increasing flood severities and frequencies, studies on coastal vulnerability assessment are of increasing concern. Evaluation of flood inundation depth and extent is the first issue in flood vulnerability analysis. This study has proposed a practical framework for reliable coastal floodplain delineation considering both inland and coastal flooding. New York City (NYC) has been considered as the case study because of its vulnerability to storm surge-induced hazards. For floodplain delineation, a distributed hydrologic model is used. In the proposed method, the severities of combined inland and coastal floods for different recurrence intervals are determined. Through analyzing past storms in the study region, a referenced (base) configuration of rainfall and storm surge is selected to be used for defining flood scenarios with different return periods. The inundated areas are determined under different flooding scenarios. The inundation maps of 2012 superstorm Sandy in NYC is simulated and compared with the FEMA revised maps which shows a close agreement. This methodology could be of significant value to the planners and engineers working on the preparedness of coastal urban communities against storms by providing a platform for updating inundation maps as new events are observed and new information becomes available.     

Methodology for preliminary assessment of Natech risk in urban areas

Concern for natural hazard-triggered technological disasters (Natech disasters) in densely populated and industrialized areas is growing. Residents living in urban areas subject to high natural hazard risk are often unaware of the potential for secondary disasters such as hazardous materials releases from neighboring industrial facilities, chemical storage warehouses or other establishments housing hazardous materials. Lessons from previous disasters, such as the Natech disaster during the Kocaeli earthquake in Turkey in 1999 call for the need to manage low frequency/high consequence events, particularly in today’s densely populated areas. However, there is little guidance available on how local governments and communities can assess Natech risk. To add to the problem, local governments often do not have the human or economic resources or expertise to carry out detailed risk assessments. In this article, we propose a methodology for preliminary assessment of Natech risk in urban areas. The proposed methodology is intended for use by local government officials in consultation with the public. The methodology considers possible interactions between the various systems in the urban environment: the physical infrastructure (e.g., industrial plants, lifeline systems, critical facilities), the community (e.g., population exposed), the natural environment (e.g., delicate ecosystems, river basins), and the risk and emergency management systems (e.g., structural and nonstructural measures). Factors related to vulnerability and hazard are analyzed and qualitative measures are recommended. Data from hazardous materials releases during the Kocaeli, Turkey earthquake of August 17, 1999 are used as a case study to demonstrate the applicability of the methodology. Limitations of the proposed methodology are discussed as well as future research needs.

Assessing building vulnerability to earthquake and tsunami hazard using remotely sensed data

Quantification of building vulnerability to earthquake and tsunami hazards is a key component for the implementation of structural mitigation strategies fostering the essential shift from post-disaster crisis reaction to preventive measures. Facing accelerating urban sprawl and rapid structural change in modern urban agglomerations in areas of high seismic and tsunami risk, the synergetic use of remote sensing and civil engineering methods offers a great potential to assess building structures up-to-date and area-wide. This paper provides a new methodology contextualizing key components in quantifying building vulnerability with regard to sequenced effects of seismic and tsunami impact. The study was carried out in Cilacap, a coastal City in Central Java, Indonesia. Central is the identification of significant correlations between building characteristics, easily detectable by remote sensing techniques, and detailed in situ measurements stating precise building vulnerability information. As a result, potential vertical evacuation shelters in the study area are detected and a realistic vulnerability assessment of the exposed building stock is given. These findings obtained allow for prioritization of intervention measures such as awareness and preparedness strategies and can be implemented in local disaster management.     

A new hybrid procedure for the definition of seismic vulnerability in Mediterranean cross-border urban areas

Assessment of seismic vulnerability of urban areas provides fundamental information for activities of planning and management of emergencies. The main difficulty encountered when extending vulnerability evaluations to urban contexts is the definition of a framework of assessment appropriate for the specific characteristics of the site and providing reliable results with a reasonable duration of surveys and post-processing of data. The paper proposes a new procedure merging different typologies of information recognized on the territories investigated and for this reason called “hybrid.” Knowledge of historical events influencing urban evolution and analysis of recurrent building technologies are used to evaluate the vulnerability indexes of buildings and building stocks. On the other hand, a vulnerability model is calibrated by means of experimental and numerical investigations on prototype buildings representative of the most recurrent typologies. In the final framework, the vulnerability index, calculated through simplified assessment forms, is linked to the seismic intensity expressed by the peak ground acceleration and associated with an index of damage expressing the economical loss. The procedure has been tested on the urban center of Lampedusa island (Italy) providing as the output vulnerability index maps, vulnerability curves, critical PGA maps, and estimation of the economical damage associated with different earthquake scenarios. The application of the procedure can be suitably repeated for medium-to-small urban areas, typically recurring in the Mediterranean by carrying out each time a recalibration of the vulnerability model.

     

Prioritization of disaster risk in a community using GIS

Prioritization of disaster risk was carried out for a community in Toronto, Canada. Geographic information systems (GIS) were used for spatial analysis, including spatial overlays and clipping for extracting spatial and attribute information related to people’s vulnerability, critical infrastructure and landuse. In order to determine disaster risk, the overall community vulnerability was evaluated by combining social, economic, physical and environmental vulnerabilities. This paper uses the propane explosion incident as the case in point to demonstrate the methodology and procedure used to evaluate risk using GIS techniques. City of Toronto spatial data have been integrated with the study area to gather landuse information, identify risk zones based on the propane storage facility location and evaluate risks. Statistics Canada 2006 census data have been used for area demographics and people’s social and economic status. Vulnerability indicators were determined based on the GIS-derived spatial and attribute data for the hazard and evacuation zones followed by a quantitative spatial risk estimation and ranking. The methodology of this study, based on the risk evaluation and prioritization conducted, can be applied to future decision making in effective landuse planning and the development of risk management strategies.     

武汉市区第四系含水层地下水有机污染敏感性研究

在详细调查武汉市水文地质条件和地下水污染现状的基础上，获得了高精度的武汉市水环境中微量有机污染物的组成数据。所检测出的有机组分达30余种，以苯及相关苯系物为主，污染程度较高的地下水主要分布在人口密集区和工业，商业区，应用改进的DRASTIC模型－地下水污染敏感性评价模型，在GIS平台上，编制了武汉市区地下水污染敏感性分区图。根据其评价结果，建议集中对那些敏感性相对较高的区域采取有效的环保措施，开发利用时应作出风险评价。     

A new hybrid procedure for the definition of seismic vulnerability in Mediterranean cross-border urban areas

Assessment of seismic vulnerability of urban areas provides fundamental information for activities of planning and management of emergencies. The main difficulty encountered when extending vulnerability evaluations to urban contexts is the definition of a framework of assessment appropriate for the specific characteristics of the site and providing reliable results with a reasonable duration of surveys and post-processing of data. The paper proposes a new procedure merging different typologies of information recognized on the territories investigated and for this reason called “hybrid.” Knowledge of historical events influencing urban evolution and analysis of recurrent building technologies are used to evaluate the vulnerability indexes of buildings and building stocks. On the other hand, a vulnerability model is calibrated by means of experimental and numerical investigations on prototype buildings representative of the most recurrent typologies. In the final framework, the vulnerability index, calculated through simplified assessment forms, is linked to the seismic intensity expressed by the peak ground acceleration and associated with an index of damage expressing the economical loss. The procedure has been tested on the urban center of Lampedusa island (Italy) providing as the output vulnerability index maps, vulnerability curves, critical PGA maps, and estimation of the economical damage associated with different earthquake scenarios. The application of the procedure can be suitably repeated for medium-to-small urban areas, typically recurring in the Mediterranean by carrying out each time a recalibration of the vulnerability model.     

地理信息系统GIS支持下的城市地质环境评价

以 GIS为支撑工具 ,对城市地质环境空间数据库的建立方法、城市建设用地类型的初步划分及城市建设用地与地质环境的协调性评价模型作了分析 ,并选取典型实例进行剖析 ,结果表明 GIS是城市地质环境研究的有效工具。