A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, February 2015. / Due to its geographical location, poor economic situation and geological features that are characterised by mostly mountainous terrain, Lesotho is vulnerable to hazardous events associated with climate, such as drought, floods, heavy snow, and severe frost. This research explores factors underlying spatial vulnerability of places to natural hazards in south-western Lesotho. Prior vulnerability assessments in Lesotho have investigated vulnerability in terms of identifying populations that are most food insecure and vulnerable to hunger. By broadening the scope of vulnerability to include biophysical and socioeconomic characteristics, the study emphasises the concept of place vulnerability as a foundation for understanding Lesotho’s vulnerability to natural hazards. Spatial orientation of vulnerability within a geographical area provides an easy way for planners and decision makers to identify areas that may require additional resources in order to prepare for disasters. To date, no quantitatively based vulnerability assessment has been undertaken in Lesotho, so this study is one of the first to assess place vulnerability to natural hazards in Lesotho using GIS and it emphasise the role of geography of a place.

Les chutes de blocs constituent un aléa naturel majeur dans les Alpes françaises en raison de leur probabilité d'occurrence spatiale et temporelle très élevée. Les forêts peuvent constituer une solution naturelle et efficace pour atténuer ce phénomène tout en protégeant les populations et leurs infrastructures. Cependant, ce service écosystémique peut être perturbé par d'autres aléas naturels comme les feux de forêts, susceptibles d'être plus fréquents et intenses dans le contexte actuel et futur de changements climatiques.Cette thèse propose ainsi d'évaluer les effets des incendies sur la capacité de protection des forêts contre les chutes de blocs dans les Alpes françaises.Une méthodologie pour évaluer la capacité de protection d'une forêt contre les chutes de blocs est d'abord développée et consiste à utiliser des simulations de propagation de chutes de blocs réalisées sur 3886 placettes forestières des Alpes françaises pour calculer trois indicateurs quantitatifs évaluant la réduction de la fréquence (BARI), de l'intensité (MIRI) et la réduction globale (ORPI) de l'aléa chutes de blocs dues à la présence d'une forêt. Ces indicateurs sont utilisés pour identifier les variables forestières prépondérantes pour évaluer la capacité de protection : la longueur boisée sur le versant, la surface terrière et le diamètre moyen. Les peuplements présentant une distribution hétérogène des diamètres et composés de plusieurs essences offrent généralement une meilleure protection que les peuplements monospécifiques et réguliers, soulignant ainsi l'influence de la diversité forestière. Cette thèse montre ainsi que les taillis présentent les capacités de protection les plus élevées, suivis par les futaies feuillues et les futaies mixtes ; les peuplements résineux venant en dernier.Les évolutions spatiales et temporelles des conditions climatiques favorables aux incendies, étudiées sur la période 1959-2015, révèlent un contraste majeur entre les Alpes du Sud qui ont connu une forte augmentation (en intensité, fréquence, durée et saisonnalité) surtout à haute altitude, et les Alpes du Nord, où une légère hausse est observée à basse altitude, mais aucune tendance significative n'est observée à haute altitude. Ces résultats sont ensuite utilisés pour définir trois types de feux (d'hiver, d'été moyen et d'été très sec) pour lesquels la mortalité post-incendie est étudiée à l'échelle de l'arbre et du peuplement forestier. Ces analyses montrent que seuls les feux d'été sont susceptibles d'affecter significativement les peuplements, en particulier à basse altitude où les peuplements feuillus (notamment les taillis) dominent.L’effet des incendies sur la capacité de protection des forêts est évalué en comparant les simulations de propagation de chutes de blocs sans feu aux simulations après chaque type de feu pour lesquelles les arbres avec une forte probabilité de mortalité post-feu ne sont pas pris en compte. Les valeurs de ORPI pour chaque placette forestière et chaque type de feu sont ainsi calculées et comparées au scénario de référence sans feu, permettant ainsi d'évaluer quantitativement la réduction de la capacité de protection. Les peuplements de basse altitude, soumis à des conditions climatiques plus chaudes et sèches, présentent des réductions de la capacité de protection après des feux d'été de l'ordre de 60 à 100 %. Il s'agit principalement de taillis et de futaies feuillues. À plus haute altitude, la réduction est de l'ordre de 30 à 65 %.En conclusion, ce travail de thèse propose une méthode originale pour quantifier la capacité de protection d'une forêt contre les chutes de blocs avant et après un incendie et alimente les connaissances sur ces deux aléas naturels et les risques associés. L'analyse multi-aléas conduite en fin de thèse permet d'appréhender les effets cascades potentiels à l'échelle du peuplement forestier et de quatre territoires bioclimatiquement homogènes des Alpes françaises. / Rockfalls are a major natural hazard in the French Alps due to their high probability of spatial and temporal occurrence. Forests constitute an efficient nature-based solution to mitigate this hazard while protecting human lives and assets. However, this ecosystem service may be disrupted by others natural hazards such as wildfires likely to be more frequent and intense in the current and future context of climate changes.This PhD thesis proposes to assess the effects of fires on the protection capability of forests against rockfalls in the French Alps.A methodology to evaluate the protection capability of a forest against rockfalls is first developed. It consists in modeling rockfalls propagations on 3886 forest plots taken in the French Alps to calculate three quantitative indicators that assess the reduction of the frequency (BARI), the intensity (MIRI) and the overall reduction (ORPI) of rockfalls due to the presence of a forest. These indicators are used to identify the predominant forest variables for assessing the protective effect: the length of forest along the slope, the basal area and the mean diameter. Forest stands with a heterogeneous distribution of diameters and made up of several tree species generally offer a better protection than monospecific and regular stands, thus underlining the influence of forest diversity. This work shows that coppices have the highest protection capabilities, followed by hight stands dominated by deciduous species and mixed stands; coniferous stands coming last.Spatio-temporal trends in fire weather in the French Alps are investigated over the period 1959-2015 and reveal a major contrast between Southern Alps which experienced a strong increase (in intensity, frequency, duration and seasonality) especially at high elevation, and Northern Alps, where a slight increase at low elevation and no significant trends at high elevation are observed. These results are then used to define three types of fires (winter, summer, and dry summer) for which post-fire tree mortality is studied at the tree and forest stands levels. These analyses show that only summer fires are likely to significantly affect the forest ecosystems, particularly at low elevations where deciduous stands (especially coppice) dominate.The effect of fires on the protection capabilities of forests is assessed by comparing rockfalls propagation simulations without fire to simulations after each type of fire in which the trees with a high post-fire mortality are not taken into account. The ORPI values for each forest plot and fire type are thus calculated and compared to the reference scenario without fire thus making it possible to quantitatively assess the reduction of the protection capabilities. Low elevation stands, subject to warmer and drier climatic conditions, show reductions of the protective effect in the range 60-100%. It mainly concerns coppices and deciduous stands. At high elevation, the reduction is in the range 30- 65%.In conclusion, this PhD thesis proposes an original method to quantify the protection capabilities of a forest against rockfalls before and after a fire and improve the knowledge of these two natural hazards and their associated risks. The multi-hazard analysis conducted at the end of the thesis makes it possible to understand the potential cascading effects in the main forest types and for four bioclimatically homogeneous territories of the French Alps.

Made available in DSpace on 2014-06-11T19:26:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-10Bitstream added on 2014-06-13T19:13:08Z : No. of bitstreams: 1 menquini_a_me_rcla.pdf: 6995160 bytes, checksum: be2e7b0c13c3c93bb2cdf685d7c9f0a7 (MD5) / A ocupação de espaço nas regiões costeiras constitui problemática de difícil solução, devido à complexidade de sua natureza. A rápida ocupação desordenada desses espaços, motivada pelo desenvolvimento econômico e potencializada por diferentes atividades turísticas, nessas últimas cinco décadas, resulta no desperdício de solo e recursos, que afetam os ecossistemas da área, provocando risco às populações fixa e flutuante. A análise geoambiental compreende a área entre a Ponta de Itaipu ao Maciço de Itatins, situada na linha de costa do Estado de São Paulo, na Região Metropolitana da Baixada Santista. Voltada às unidades geomorfológicas praias, manguezais, morros e encosta, a análise fornece dados para conhecimento dos processos críticos de erosão, deslizamento e inundação existentes na área desse estudo. O levantamento desses dados auxilia a equação dos principais fatores geológicos e geomorfológicos que influenciam o controle das áreas onde ocorre a interação entre os complexos ecossistemas urbanos e os ecossistemas costeiros em equilíbrio dinâmico. O estudo compreende diferentes fases: reconstrução histórica da colonização, emancipação dos municípios que integram a área de estudo, análise das características de ocupação, bem como a comparação de fotografias aéreas (1962 com 2002) e trabalho de campo. Assim, foram identificados dezesseis pontos de áreas críticas, constatando-se que processos críticos têm origem no uso indevido do solo, principalmente no desmatamento. Para a racionalização do uso do solo e recursos, que preservam os ecossistemas, minimizam e até evitam risco à população, propõe-se que seja trabalhada a cultura de segurança, indicada no Planejamento Ambiental dos programas direcionados ao Desenvolvimento Sustentável, contida na Agenda 21, que trata da Promoção do Desenvolvimento Sustentável... / The space occupation in coastal regions is always a difficult problem to be solved due to the environmental complexity of these areas. The rapid and disorganized occupation in the studied area is due to the economic development and by tourist activities in these last fifty decades. These combined actions had a direct impact into soil waste and other resources that affect the whole area ecosystems leading to risks to the fixed and seasoning population. A geoenvironment analysis was carried on in the coastal line of the São Paulo State between the Ponta de Itaipu and Maciço de Itatins located in the Região Metropolitana of the Baixada Santista. This analysis had been concentrated in the geomorphological units of beaches, mangroves and topographic elevated terrains within, this area, and its results leads to better understanding of the critical processes of erosion, floods and landslides presently in action. The resulting data also allows to the better knowledge of main geologic and geomorphologic factors equation that affects these areas where we have the interaction of complex urban ecosystems and coastal ecosystems of dynamic equilibrium. The historical reconstruction from the beginning of the colonial time to the present days with the analysis of the specific characteristics of the different types of occupation, the comparison of air photos dated from 1962 to those of 2002 and field work, allowed to the identification of sixteen critical points in this area. The critical processes is mainly a result of the undue soil management specially its deforestation. It is here proposed to these areas the use of the principle of safety culture as indicated by the Environmental Planning as mentioned in the Sustentation Development Program inside of the Agenda 21 that deals with the promotion of the sustainable development of the humans enrolments... (Complete abstract, access undermentioned electronic address)

Made available in DSpace on 2014-06-11T19:33:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-22Bitstream added on 2014-06-13T18:44:52Z : No. of bitstreams: 1 almeida_lq_dr_rcla.pdf: 17677431 bytes, checksum: ea6571858fa70223c40e497bfb39dacf (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Les fleuves urbains au Brésil sont synonymes d'environnements dégradés, dévalués et niés par la société. Ces espaces se sont rendus alternative d'accès au logement pour une masse de pauvres qui ne peuvent pas acquérir un espace sûr la ville. La jonction de pauvreté, d'habitation improvisée, peu d'infrastructure, avec l'occupation d'espaces exposés à des aléas naturels, a créé des territoires de risques et des vulnérabilités, qui fréquentement coïncident avec les environnements fluviaux urbains. Ainsi, il s'est défini comme principale proposition de cette thèse analyser les risques et les vulnérabilités socio-environnementaux de fleuves urbains au Brésil, en ayant le bassin hydrographique du fleuve Maranguapinho, localisé dans la Région Métropolitaine de Fortaleza - RMF, Ceará, comme espace d'étude de cas pour compréhension des interrelations entre des vulnérabilités sociales et exposition aux risques naturels, principalement les risques d'inondations. La méthodologie utilisée a employé des techniques statistiques, de la superposition cartographique, des incursions dans l’espace d’étude, pour produire un indice de vulnérabilité socio-environnementaux du secteur étudié. Il s'est conclu qu'il y a des forts coïncidences entre les espaces susceptibles à des processus naturels dangereux, comme est le cas des inondations - processus naturel remorque à la dynamique des fleuves et de leurs bassins hydrographiques, et les espaces de la ville qui présentent les pires indicateurs sociaux, économiques et de l'accès à des services et l'infrastructure urbaine / Os rios urbanos no Brasil são sinônimos de ambientes degradados, desvalorizados e negados pela sociedade. Esses espaços se tornaram a alternativa de acesso à moradia para uma massa de pobres que não podem adquirir um espaço seguro na cidade. A junção de pobreza, habitação improvisada, pouca infraestrutura, com a ocupação de espaços expostos a perigos naturais, criou territórios de riscos e vulnerabilidades, que frequentemente coincidem com os ambientes fluviais urbanos. Assim, definiu-se como principal proposta desta tese analisar os riscos e as vulnerabilidades socioambientais de rios urbanos no Brasil, tendo a bacia hidrográfica do rio Maranguapinho, localizada na Região Metropolitana de Fortaleza – RMF, Ceará, como área de estudo de caso para compreensão das inter-relações das vulnerabilidades sociais e exposição aos riscos naturais, principalmente os riscos de inundações. A metodologia utilizada empregou técnicas estatísticas, sobreposição cartográfica, trabalhos de campo, para produzir um índice de vulnerabilidade socioambiental da área estudada. Concluiu-se que há fortes coincidências entre os espaços susceptíveis a processos naturais perigosos, como é o caso das inundações – processo natural atrelado à dinâmica dos rios e de suas bacias hidrográficas, e os espaços da cidade que apresentam os piores indicadores sociais, econômicos e de acesso a serviços e infraestrutura urbana / The urban rivers in Brazil are synonymous of degraded, devaluated and denied environments for the society. These spaces had become the alternative access to housing for a mass of poor persons who cannot acquire a safe space in the city. The junction of poverty, improvised habitation, little infrastructure, with the occupation of prone spaces to the natural hazards, created territories of risks and vulnerabilities, that frequently coincide with urban fluvial environments. Thus, the main proposal of this thesis is to analyze the risks and the socioenvironmental vulnerabilities of urban rivers in Brazil, having being chosen the the Maranguapinho river hydrographic basin as case study area, located in the Metropolitan Region of Fortaleza - MRF, Ceará, to the understanding of the inter-relations between social vulnerabilities and exposure to the natural risks, mainly the risks of floodings. The methodology used statistical techniques, cartographic overlapping, field research, to produce an socio-environmental vulnerability index of the case study area. It was concluded that it has serious coincidences between the susceptibles spaces to natural hazards processes, e.g floodings – natural process linked to the rivers’ dynamics and its hydrographic basin, and the spaces of the city that present the worse social, economic, access the services and urban infrastructure index

Dans les sociétés insulaires souvent vulnérables, l’omniprésence de phénomènes naturels (cyclones, séismes, éruptions volcaniques, mouvements de terrain, inondations) représente des risques majeurs et engendre des crises fréquentes. Une analyse des modes de gestion de crises mouvement de terrain est proposée dans un espace précis : les Petites Antilles. Véritable laboratoire, cet espace rassemble les conditions morphoclimatiques propices à l’occurrence des mouvements de terrain. La notion de territoire est importante dans l’étude des crises, car un aléa ne devient un risque et éventuellement une crise que s’il concerne une zone présentant des enjeux plus ou moins vulnérables (populations, infrastructures, etc.). Dans ce sens, le choix des Petites Antilles est intéressant car dans une même zone il y a la possibilité d’étudier des cas de crises dans plusieurs territoires insulaires dont le fonctionnement économique, l’organisation politique et les niveaux de vie sont différents. L’étude montre que malgré ces différences, ils sont face à des problématiques similaires en termes de récurrence des phénomènes mouvements de terrain, d’ampleur des dommages et d’investissements coûteux. Par conséquent, l’observation des particularités de ces territoires et la complexité des phénomènes mouvements de terrain a abouti à l’étude des crises et de leur mode de gestion par le biais d’une démarche méthodologique systémique et comparative. Elle se fonde sur une double sélection. Grâce à un travail d’inventaire débouchant sur des typologies, des îles ainsi que des évènements mouvements de terrain spécifiques furent retenus. Approcher ces phénomènes géomorphologiques sous cet angle en plaçant la gestion de crise au cœur de l’analyse, a permis de mettre en exergue les relations systémiques entre les composantes territoriales que sont : le phénomène mouvement de terrain, les populations avec leurs activités, leurs modes d’emprises spatiales, et leur vulnérabilité. Ce travail de confrontation des modes de gestion de crise par un raisonnement systémique a permis de comprendre comment des évènements mouvements de terrain entraînant une crise traduisent un fonctionnement sociétal particulier dans différents territoires des Petites Antilles. / In the often vulnerable island societies, the omnipresence of natural phenomena (hurricanes, earthquakes, volcanic eruptions, landslides, floods) represents major risks and causes frequent crises. An analysis of landslide crisis management is proposed in a specific area: the Lesser Antilles. Real laboratory, this space brings together the morphoclimatic conditions for landslide occurrence. The notion of territory is important in the study of crises because a hazard becomes a risk and possibly a crisis only if it concerns an area with more or less vulnerable stakes (people, infrastructure, etc.). In this sense, the choice of the Lesser Antilles is interesting because in the same area there is the opportunity to study cases of crises in several island territories whose economy, political organization and living standards are different. The study shows that despite these differences, they are faced with similar problems in terms of landslides recurrence, extent of damage and costly investment. Therefore, the observation of the particularities of these territories and the complexity of landslide led to the study of crises and their management through a systemic and comparative methodological approach. It’s based on a double selection. With a work inventory leading on typologies, islands and specific landslide events were retained. Studying these geomorphic phenomena by placing the crisis management at the heart of the analysis allowed to highlight the systemic relations between the territorial components which are: the landslide event, people with their activities, their modes space allowances, and their vulnerability. This confrontation of the crisis management by systemic approach helped to understand how landslide events causing a crisis reflected a specific societal functioning in different territories of the Lesser Antilles.

Dans les régions exposées à des aléas naturels, une large partie des bâtiments composant l'environnement construit sont réalisés presque exclusivement sur la base de l'expérience et de l'observation des bâtisseurs locaux, sans l'appui d'un architecte ou d'un ingénieur. Les communautés installées dans ces zones ont développé, au fil du temps, une multitude de stratégies pour co-habiter avec ces phénomènes, incluant des comportements sociaux et des approches de construction visant à prévenir et/ou à limiter l'exposition du bâti et de ses habitants. En fait, les constructeurs ont souvent intégré la présence et les caractéristiques locales des aléas naturels dans leurs pratiques quotidiennes, élaborant des détails et des dispositions constructives particulières pour réduire la vulnérabilité des artefacts et du milieu bâti. Le concept de culture constructive embrasse la dimension sociale et technique de l'acte de construire et du processus d'élaboration des savoirs et savoir-faire qui lui sont inhérents, reflétant intrinsèquement la multiplicité des sociétés humaines et leur enracinement indissoluble au territoire qu'elles habitent. Le vernaculaire en tant que caractérisation des modes de bâtir, d'habiter et de se protéger se révèle par ce fait une source précieuse de pratiques, techniques et mesures, testées au cours des siècles et des multiples aléas, pour la construction d'environnements bâtis durables, accessibles et sûrs. Ce travail de recherche explore le potentiel présenté par les cultures constructives vernaculaires dans le renforcement de la résilience locale. Et cela à partir des pratiques - constructives et comportementales - développées par les populations, groupes et individus habitant des contextes géographiquement exposés à des aléas naturels. Se fondant sur une forte interaction entre la théorie et la pratique, cette recherche entame une (re)découverte de l'ingéniosité intrinsèque à ces savoirs par le développement de deux axes thématiques. L'un investigue les dispositions et les dispositifs vernaculaires à caractère parasinistre ayant démontré leur efficacité à réduire la vulnérabilité de l'environnement construit envers différents types d'aléas naturels. L'autre axe questionne les modalités de leur identification et contribution directe au renforcement des capacités de populations et institutions dans la gestion des crises. À une analyse technique s'associe l'élaboration d'un outil méthodologique soutenant la mise en place d'une démarche de projet s'ancrant fortement aux spécificités contextuelles selon une logique de continuité, tant culturelle que de pratique, entre passé et futur, entre préparation et réponse aux catastrophes. / In areas prone to natural hazards, many of the buildings that make up the built environment are constructed almost exclusively through the experience and the direct observation of local builders, without the support of any architect or engineer. In these regions, communities have developed over time a variety of strategies to cope with natural phenomena through patterns of social behaviours and building approaches intended to prevent and/or to reduce their exposure to local risks. Similarly, local builders have often integrated natural hazards into their daily practices, developing singular techniques, building details or devices aiming to reduce the vulnerability of the built environment. The concept of building culture embraces the social and technical aspects related to the construction process and to the development of corresponding knowledge and know-how, intrinsically reflecting the multiplicity of human societies and their indissoluble connection with the territories they inhabit. The vernacular as characterization of ways of building, living and protecting oneself proves to be a valuable source of practices, techniques and measures, tested over the years and during multiple hazards, for contemporary construction of sustainable, accessible and safe built-environments. This research explores the potential of vernacular building cultures in enhancing local resilience; and this starting from - constructive and behavioural – practices developed by individual people and groups living in contexts geographically exposed to natural hazards. Based on a strong interaction between theory and action, this research undertakes a (re)discovery of vernacular knowledge through two thematic focuses. One examines disaster resilient vernacular provisions and devices which have demonstrated their effectiveness to reduce vulnerability of the built environment to various types of natural hazards. The other one considers ways for their identification and direct contribution to strengthening capacities of communities and institutions for disaster risk management. This research combines a technical analysis with the development of a methodological tool, contributing to set up a project approach strongly rooted into contextual specificities, linking culture and practice, past experience and future needs, disaster response and preparedness.

Depuis le 19ème siècle, de nombreux dispositifs de protection ont été implantés en montagne pour réduire le risque torrentiel. L'évaluation multi-échelle de leur efficacité est nécessaire pour comparer et choisir les stratégies de maintenance et de gestion de l’occupation des sols. Le chapitre I met en évidence les ambiguïtés du concept d’efficacité évalué selon plusieurs critères dans un contexte d’information imparfaite, issue de sources multiples, inégalement fiables. Pour aider l’évaluation multidimensionnelle, le problème de décision est décomposé en plusieurs sous-problèmes formulés, modélisés, traités puis intégrés. L’état de l’art du chapitre II permet de retenir les méthodes de la sûreté de fonctionnement (SdF) et d'aide à la décision (AD) basées sur le Raisonnement Évidentiel, associant les ensembles flous, les possibilités, les fonctions de croyance et la fusion d’information pour traiter chaque problème. Le chapitre III explicite le concept d'efficacité puis propose une adaptation des méthodes de la SdF à la formulation multi-échelle des problèmes. Le chapitre IV adapte les méthodes d'AD basées sur le Raisonnement Évidentiel, les améliore pour mieux représenter la connaissance disponible et évaluer la qualité d’une décision, et les associe. Le chapitre V propose une méthodologie séquentielle qui intègre ces méthodes pour évaluer les mesures de protection, de l’échelle de l’ouvrage à celle du bassin d’enjeux. Enfin, le chapitre VI discute les résultats, identifie les apports respectifs de l'intégration et des nouvelles méthodes, puis décrit les perspectives de déploiement opérationnel de la méthodologie développée. / Many torrential protective check dams have been built in French mountainous areas since the 19th century. They aim to reduce risk in torrential watersheds. Analysis of their effectiveness is needed to assess residual risk and to choose the best maintenance strategy in a context of reduced budgets. Chapter I introduces main issues due both to definition of effectiveness concept and also the several criteria and system scales that have to be assessed. Moreover, required expertise is based on imperfect information, provided by several sources with different reliability levels. To help such decisions, this thesis proposes to break down general assessment into several smaller decision-making problems. In chapter II, dependability analysis tools and Evidential Reasoning based-decision-aiding methods (ER-DAMs), using fuzzy sets and possibility theories, are chosen to help individual decisions. Chapters III to V then introduce new developments. Effectiveness concept is first defined. A multi-scale dependability analysis helps to describe each decision-making problem. ER-DAMs are then adapted to help effectiveness assessment at each system’s scale. Technical improvements are provided to these methods for a better knowledge representation and final decision. Improved methods are then associated. Finally, individual problems and associated methods are integrated in a generic methodology to help torrential protective measures’ effectiveness assessment at watershed scale. The last chapter VI focuses on discussion of integrative aspects and of ER-DAMs’ specific developments. It gives some elements to improve methods but also to help operational implementation of the generic methodology.

As a result of the United Nations’ International Decade for Natural Disaster Reduction (1990-2000), and recent high profile disasters, disaster risk reduction has climbed high on the international political agenda. There has been a paradigm shift from reacting to disasters towards preparing for and mitigating effects of disasters. Among the measures that have been highlighted on the disaster risk reduction agenda are early warning systems. In a Swedish context, there are needs for early warnings for various flood risk types. Municipalities carry big responsibilities for managing flood risks, and early warnings have a potential to facilitate decision-making and ultimately reduce flood losses. The aim of this thesis is to describe how a variety of flood warning signals are used in the risk management process of Swedish municipalities, how they can contribute to the flood risk reducing process, and which factors influence the success of this. The thesis is based on two papers. Paper I is based on interviews with three respondents from Swedish municipalities that have invested in and established local early warning systems. The paper shows that the possible effects from a local early warning system are not only reduced flood losses but also potential spinoff, the occurrence of which is dependent on the well-being of the organisation and its risk management processes. Paper II is based on interviews with 23 respondents at 18 Swedish municipalities, who have responsibilities related to flood risk management, and one respondent who works at SMHI with hydrological warning. The paper shows that municipalities can use a variety of complementary flood warning signals to facilitate decision-making for a proactive flood response. This is however not systematically the case, and is dependent on available resources. The theoretical contribution of this thesis is a development of existing conceptual models of early warning systems with respect to risk management and system contexts, and the use of complementary warning signals. / Following the United Nations’ International Decade for Natural Disaster Reduction (1990-2000), and recent high profile disasters, disaster risk reduction has climbed high on the international political agenda. Among the measures that have been highlighted are early warning systems – for Swedish municipalities who are responsible for managing flood risks, early warnings have a potential to facilitate decision-making and ultimately reduce flood losses. This licentiate thesis, based on two articles, aims to describe how a variety of flood warning signals are used in the risk management process of Swedish municipalities, how they can contribute to the flood risk reducing process, and which factors influence the success of this. The articles show that the possible effects from a local early warning system are not only reduced flood losses but also potential spin-off benefits, the occurrence of which is dependent on factors such as organisational culture and the functioning of the wider risk management system, and that municipalities can use a variety of complementary flood warning signals to facilitate decision-making for a proactive flood response which, however, is not systematically the case as benefits are dependent on available resources.

Disaster risk reduction policies and practitioners alike emphasise the importance of vulnerability reduction. However, the concept of vulnerability is highly dynamic, and research still strives to understand and capture its complexity. The purpose of this study was to improve the understanding of flood vulnerability in rural disaster-prone communities in Mozambique. To explore previous experiences of floods, I conducted semi-structured interviews with local risk committee members and community members in the lower Limpopo river basin. The findings were analysed with an analytical framework consisting of the Disaster Pressure and Release (PAR) model, drawing on political ecology and the Access model. Disaster was studied as a process revealing important factors, capabilities and strains affecting peoples’ vulnerability. This paper illustrated that rural communities in the lower Limpopo river basin are vulnerable to floods in a variety of ways. The findings presented unsafe conditions such as the fragile local economy, unsafe natural resources, strained physical resources and limited access to human and social capital. Several factors deriving from political, social and economic structures were found to influence specific forms of vulnerability expressed in relation to floods. Therefore, this paper contributes to new insights of how flood vulnerability can be described and explained in Mozambique.

Natural hazards are predicted to only increase in frequency and severity over the next decade, making it crucial to avoid their negative consequences by disaster risk reduction. Reducing risks of natural hazards is not a recent invention as it has been shown that indigenous and local communities possess indigenous and local knowledge systems related to reducing disaster risks. These knowledge systems are however largely being ignored in policy and research. They are also subjected to pressures which risk altering, eroding or destroying them. In this thesis, these indigenous and local knowledge systems and the pressures that might threaten them are explored through a field study with interviews and observations in rural indigenous and local communities in northern Thailand. The findings show clear evidence of multiple and varying types of indigenous and local knowledge systems, such as knowledges, practices, and beliefs that reduce disaster risk. However, multiple types of pressures to the indigenous and local knowledge systems are also found. These pressures have in some cases already resulted in a loss of indigenous and local knowledge systems, or risk doing so in the future. The conclusion of the thesis is that these indigenous and local knowledge systems and the pressures to them should be kept in close mind in research, policy and intervention to improve disaster risk reduction and not perpetuate the current western paradigm.