Alexandre Oliveira Tavares

DISASTER: a GIS database on hydro-geomorphologic disasters in Portugal

AbstractIn the last century, Portugal was affected by several natural disasters of hydro-geomorphologic origin that often caused high levels of destruction. However, data on past events related to floods and landslides were scattered. The Disaster project aims to bridge the gap on the availability of a consistent and validated hydro-geomorphologic database for Portugal, by creating, disseminating and exploiting a GIS database on disastrous floods and landslides for the period 1865–2010, which is available in http://riskam.ul.pt/disaster/en. Data collection is steered by the concept of disaster used within the Disaster project. Therefore, any hydro-geomorphologic case is stored in the database if the occurrence led to casualties or injuries, and missing, evacuated or homeless people, independently of the number of people affected. The sources of information are 16 national, regional and local newspapers that implied the analysis of 145,344 individual newspapers. The hydro-geomorphologic occurrences were stored in a database containing two major parts: the characteristics of the hydro-geomorphologic case and the corresponding damages. In this work, the main results of the Disaster database are presented. A total of 1,621 disastrous floods and 281 disastrous landslides were recorded and registered in the database. These occurrences were responsible for 1,251 dead people. The obtained results do not support the existence of any exponential increase in events in time, thus contrasting with the picture provided to Portugal by the Emergency Events Database. Floods were more frequent during the period 1936–1967 and occurred mostly from November to February. Landslides were more frequent in the period 1947–1969 and occurred mostly from December to March.

Re-scaling risk governance using local appraisal and community involvement

This paper describes a risk governance model applied on a local scale, showing the advantages and constraints found during its application. The risk governance model, built on a municipal scale, results from the application of the International Risk Governance Council framework. The model is characterised by the cyclicity between the assessment and management spheres, assuming communication to be essential in all stages. Its application in central Portugal is rooted in a specific knowledge of hazards and their impacts, the human and financial constraints, and the expectations of citizens and stakeholders. The results show that preformatted management solutions derived from national civil protection stakeholders can be adapted to a local physical, social and institutional context. It was found that this depends significantly on the stakeholders’ concerns assessment, as this allows the subsequent risk management options to be adapted and legitimised. As a result, more appropriate land-use regulations and mitigation strategies are being designed, which are related to urban planning, road design, risk sensitisation and communication tools. However, two features are likely to lead to an overlapping of competences and conflicts concerning responsibility for decision-making in the actual civil protection structure: the current constraints on resources on an operational level and the potentially inadequate representation of stakeholders on a strategic level.

A local-scale approach to estuarine flood risk management

New challenges in flood risk management are raised by climate change and land-use development. These challenges are particularly complex in estuarine and coastal systems, where different hazard sources interact in a dynamic socio-economic context. This paper presents an innovative approach to support flood risk management in estuaries. The approach, developed at a local-scale basis, is applied in the case study of the Tagus estuary (Portugal). The methodology is supported by the regional framing of the study area and integrates hazard, exposed elements, territorial vulnerability and risk assessments considering different climate scenarios. Through the involvement of the various risk management dimensions, the results allow the definition of a new decision-making supporting framework for emergency and land-use planning. At the emergency level, the results include a WebGIS interface providing an early warning system for the locations with highest risk of flooding and the definition of emergency planning guidelines. A set of flood adaptation actions based on land-use and occupation measures are recommended to increase resilience in face of flooding and future sea level rise. The institutional capacity-building is achieved through the availability of information and tools that can effectively support decision-making. Additionally, the outcomes contribute to better understand flood risk in estuaries and to strengthen its prevention, preparedness and response, priorities defined in the Sendai Framework for Disaster Risk Reduction 2015–2030.

The relevance of physical forces on land-use change and planning process

This study analysed the importance of physical forces on land-use change, on the planning framework in a Portuguese periurban area. A temporal matrix showing the trajectories of land transformation was obtained. A multivariate redundancy analysis explored the importance of physical parameters on temporal and spatial land-use change. A content analysis on urban or municipal master plans was made framing the importance of physical parameters on the planning process. The results highlighted a consistent trajectory of profound land-use changes with distinctive trajectories, with increasingly complex patterns with a limited dependence on physical variables. The trajectories were more related to the planning framework, where political actors and planning managers seemed to be most important. A theoretical model balancing three main components – physical forces, actors, and land transformation (DFA-C model) is proposed, reflecting the informal relationships between physical parameters and actors during the planning process.

The multiscale importance of road segments in a network disruption scenario: a risk-based approach

This article addresses the problem of the multiscale importance of road networks, with the aim of helping to establish a more resilient network in the event of a road disruption scenario. A new model for identifying the most important roads is described and applied on a local and regional scale. The work presented here represents a step forward, since it focuses on the interaction between identifying the most important roads in a network that connect people and health services, the specificity of the natural hazards that threaten the normal functioning of the network, and an assessment of the consequences of three real-world interruptions from a multiscale perspective. The case studies concern three different past events: road interruptions due to a flood, a forest fire, and a mass movement. On the basis of the results obtained, it is possible to establish the roads for which risk management should be a priority. The multiscale perspective shows that in a road interruption the regional system may have the capacity to reorganize itself, although the interruption may have consequences for local dynamics. Coordination between local and regional scales is therefore important. The model proposed here allows for the scaling of emergency response facilities and human and physical resources. It represents an innovative approach to defining priorities, not only in the prevention phase but also in terms of the response to natural disasters, such as awareness of the consequences of road disruption for the rescue services sent out to local communities.

Numerical modelling and evacuation strategies for tsunami awareness: lessons from the 2012 Haida Gwaii Tsunami

On October 28, 2012, an earthquake occurred offshore Canada, with a magnitude Mw of 7.8, triggering a tsunami that propagated through the Pacific Ocean. The tsunami numerical model results show it would not be expected to generate widespread inundation on Hawaii. Yet, two hours after the earthquake, the Pacific Tsunami Warning Centre (PTWC) issued a tsunami warning to the state of Hawaii. Since the state was hit by several tsunamis in the past, regular siren exercises, tsunami hazard maps and other prevention measures are available for public use, revealing that residents are well prepared regarding tsunami evacuation procedures. Nevertheless, residents and tourists evacuated mostly by car, and because of that, heavy traffic was reported, showing that it was a non-viable option for evacuation. The tsunami caused minor damages on the coastline, and several car accidents were reported, with one fatality. In recent years, there has been a remarkable interest in tsunami impacts. However, if risk planners seem to be very knowledgeable about how to avoid or mitigate their potential harmful effects, they seem to disregard its integration with other sectors of human activity and other social factors.

Multidimensional Approach for Tsunami Vulnerability Assessment: Framing the Territorial Impacts in Two Municipalities in Portugal

This study presents a new multidimensional methodology for tsunami vulnerability assessment that combines the morphological, structural, social, and tax component of vulnerability. This new approach can be distinguished from previous methodologies that focused primarily on the evaluation of potentially affected buildings and did not use tsunami numerical modeling. The methodology was applied to the Figueira da Foz and Vila do Bispo municipalities in Portugal. For each area, the potential tsunami-inundated areas were calculated considering the 1755 Lisbon tsunami, which is the greatest disaster caused by natural hazards that ever occurred in Portugal. Furthermore, the four components of the vulnerability were calculated to obtain a composite vulnerability index. This methodology enables us to differentiate the two areas in their vulnerability, highlighting the characteristics of the territory components. This methodology can be a starting point for the creation of a local assessment framework at the municipal scale related to tsunami risk. In addition, the methodology is an important support for the different local stakeholders.

Associations between lithology and land-use in a wine production region (Bairrada region, Portugal)

In this work, we analyze the spatial relationships between land-use and lithology in the wine production region of Bairrada (Portugal) and present a new lithological map (1:50,000) created for the region, highlighting the associations with specific types of land-use. The study was focused on the area of Bairrada that establishes the appellation DOC-VQPRD wines. The region shows a heterogeneous lithology and land-use and it is found that these two variables are not independent. Three different zones with characteristic land-use and geology can be distinguished in Bairrada: a western zone where aeolian sand deposits are associated with coniferous forests; an eastern zone with Precambrian and Paleozoic metasedimentary units associated with broad leaf forests; and a central zone with diversified Mesozoic and Cenozoic units in which most vineyards are placed. There is a clear association between a Jurassic marly and dolomitic unit and an occupation by vineyards, which is particularly obvious when larger vineyards are considered. The vineyards are also common when these Jurassic units are covered by relatively thin siliciclastic sediments.

Processos de perigosidade natural no município de Câmara de Lobos – Madeira. : Contributo para a gestão do risco e da emergência

EnglishThe present study approaches the thematic of natural risks in the township of Câmara de Lobos, including a hazard analysis, in which the socioeconomic/structural elements, with a higher degree of exposure, will be identified. The main purpose of this article is to optimize and provide a tool in territorial management policies, throughout the application of a risk and emergency management system. portuguesO presente estudo aborda a area tematica dos riscos naturais, no Municipio de Câmara de Lobos, nomeadamente uma analise dos processos de perigosidade natural, na qual serao identificados os elementos socioeconomicos/ estruturais com maior grau de exposicao. Tem como objectivo a optimizacao das politicas de gestao do territorio, atraves da aplicacao de um sistema de gestao municipal do risco e de emergencia.

Estuarine flooding in urban areas: enhancing vulnerability assessment

Abstract The assessment of vulnerability provides valuable knowledge in the risk assessment steps of a risk governance process. Given the multiscale, multilevel, and multisectorial aspects of flood risk, the diversified entities that directly and indirectly intervene in risk management require specific outputs from the assessment studies. Urban areas in estuarine margins are particularly exposed and vulnerable to flooding. Such interface conditions are found in the Old City Centre of the Seixal, located in the Tagus estuary, Portugal. Here, two distinct methodologies were applied for the assessment of territorial vulnerability. A regional, lower-scale, methodology explores the application of the statistical procedure based on the SoVI® at the statistical block level. A second, local and higher-scale, methodology is based in data collected through field matrices at the building and statistical sub-block level. Comparison of results revealed that the lower-scale assessment provides information on the vulnerability drivers at the regional and municipal level. Nevertheless, only at a higher-scale, it is possible to characterize and differentiate the smaller geographical units of analysis that compose the Old City Centre of Seixal. The lower-scale vulnerability assessment allows a strategic response, based on adaptation measures such as spatial planning, institutional capacity building and public awareness. The local level assessment provides more accurate knowledge to support local emergency planning and the allocation of operational and material resources at the urban level. Nevertheless, rather than antagonistic, both models can be considered as complementary, having in mind the requirements of an holistic flood risk governance model.