This research investigates flood-risk communication challenges in Canada, emphasizing the need for tailored strategies to address diverse household preferences and values. In Chapter 2, we examine Canadian household experiences with flood-risk information, aiming to identify new communication needs and bridge the gap between households and flood-risk managers. The interviews reveal previously overlooked flood risk information needs. The importance of tailored communication strategies was highlighted by household participants as they emphasized the need for information that caters to their unique circumstances and requirements. Moreover, fairness emerged as a crucial aspect of flood-risk communication, prompting a call for equitable practices to address vulnerabilities affecting specific households. In Chapter 3, we investigate household values and preferences on flood-risk information through a survey of at-risk households in Canada, uncovering diverse preferences, values and needs for tailored risk information. Additionally, significant differences in flood-risk knowledge, accessibility, and transparency are observed among risk-status groups, with higher awareness among those who perceive themselves at risk. Overall, this research emphasizes the importance of understanding diverse values and preferences within households regarding flood-risk information. Strengthening flood-risk communication strategies and addressing information gaps can lead to more informed risk perceptions and improve awareness among at-risk households in Canada / Thesis / Master of Arts (MA) / This research focuses on how people in Canada receive information about flood risks and how we can improve it. In Chapter 2, we talked to Canadian households to learn about their experiences with flood-risk information. We found that the current way of giving this information might not meet everyone's needs. People want information that fits their specific situations, and they stressed the importance of fairness in how the information is shared. In Chapter 3, we conducted a survey among households at risk of flooding in Canada to find out what kind of information they prefer. We discovered that people like to get clear and direct messages with detailed risk information that is customized for them. We also noticed that some people who think they are at higher risk of flooding are more informed about the risks. This means it's essential to consider how people see their own risk levels when communicating with them effectively. Overall, this research shows that flood-risk information needs to be tailored to people's different preferences and values. By doing this, we can help individuals and communities better understand and prepare for flood risks. We recommend working together with different groups involved in flood-risk management to improve how we communicate these risks. By doing so, we can create a more informed and inclusive flood-risk communication system that helps communities stay safe during flood events in the future.

Flood risk management in the U.S. has contributed to overdevelopment in at-risk areas, increases in flood losses over time, significant deficits in federal emergency programs, and inequitable outcomes to households and communities. Addressing these issues in a cost-effective and socially equitable manner relies on the ability of policy analysts to identify and understand complex interactions that characterize coupled natural-human systems, and tools for accurate estimates of the risks that arise from these interactions. This dissertation addresses this need by developing and investigating a flood risk analysis system that integrates data on property locations, assessments and transactions, high resolution flood hazard models, and flood risk policy and impacts across the coterminous United States. We focus on the degree to which markets accurately value their exposure to flooding and its impacts, and the accuracy of procedures and tools to estimate flood losses. In the first chapter, we identify heterogeneous valuation of storm risk in the Florida Keys that depends on the presence of structural defense and proximity to damaged homes after Hurricane Irma. This result suggests that stranded assets, properties with increasing vulnerability to storms but unable to rebuild structures and recover wealth, and overvalued assets at risk, which raise disaster costs, can occur simultaneously. This runs counter to the common framing of competing drivers of observed market valuation. In the second, we show that conventional methods employed in flood loss assessments to achieve large spatial scales introduce large aggregation bias by sacrificing spatial resolution in inputs. This investigation adds important context to published risk assessments and highlights opportunities to improve flood loss estimation uncertainty quantification which can support more cost effective and equitable management. In the final chapter, we conduct a nationwide study to contrast the predictive accuracy of predominantly used U.S. agency flood damage prediction models and empirical alternatives using data on 846 K observed flood losses to single-family homes from 446 flood events. We find that U.S. agency models mischaracterize the relationships of losses at the lowest low and high inundation depths, for high-valued structures, and structures with basements. Evaluated alternatives improve mean accuracy on these dimensions. In extrapolation to 72.4 M single-family homes in the U.S., these differences translate into markedly different predictions of U.S.-wide flood damages to single-family homes. The results from this dissertation provide an improved empirical foundation for flood risk management that relies on the valuation and estimation of flood risk from county to continental scales.

Climate change is predicted to alter the rainfall patterns in the future, and extreme rain events with large rainfall volumes will become more frequent and intense which increases the flood risk. A clear trend can be seen, where more and more people decide to relocate from rural to urban areas. The concentration of people, infrastructure, businesses and social services in urban areas makes them particularly vulnerable to floods due to the large economic consequences that ensue. Analyzing the future flood risk is therefore of high importance in order to adapt to the changing climate and lower the consequences of future floods. Estimating the flood risk of an area is complicated and usually abstract, especially as i) the definition and understanding of risk varies a lot, ii) there is a large shortage of consistent data and iii) decision management plans are made several years ahead even though it’s hard to predict how cities will evolve. In a hydro-economical flood risk analysis, the risk is expressed in monetary terms, here in terms of Expected Annual Damage (EAD). In order to calculate the true risk of an area, EAD, for any given year there is a need of calculating all consequences for “all” events. With today’s technical limitations it is not possible to compute all possible events in an effective way, which makes the practice both time-consuming and expensive, therefore usually only a several events are considered. Among others, this paper aim to give a better understanding of how this several events should be picked to still get a good estimation. A flood risk assessment of the city Tierp, Sweden, was performed as part of the master thesis for use as decision support. The flood hazard was mapped through hydrodynamic modelling using the 2D-modelling program MIKE21 developed by DHI. The model simulated the future flood extent in the year 2100 by using precipitation corresponding to the return periods 1, 2, 5, 10, 20, 30, 50, 100, 200 and 500 years, with a climate factor of 1.25. The economic consequences were evaluated in the DHI program City Adaptation Decision Support System (CADSS) where the flood maps were overlaid with assets of different categories with assigned damage costs. The program allowed calculation of the flood risk in terms of an expected annual damage (EAD), and the choice and combination of return periods when calculating the EAD was assessed to see how it affects the outcome. Furthermore, sustainable drainage systems (SuDS) were implemented in the hydrodynamic model and a hydro-economic analysis was performed through a cost-benefit analysis to find the optimum design return period of the structures. The flood risk assessment showed that Tierp would face an EAD of 4 304 181 SEK in the year 2100 if climate change predictions proved accurate. The accuracy of the EAD calculation was found to increase with the number of included return periods, where the inclusion of lower return periods was seen to have a larger impact on the outcome compared to higher return periods. The hydro-economic optimization of mitigation structures concluded that the optimum design return period is 50 years, and the benefit of implementing SuDS of larger dimensions is minimal. However, more dimensions need to be included in the optimization to validate this result.  Flood risk assessments have a large potential for being used as decision support in Sweden, but lack of national damage cost data makes the result uncertain and difficult to validate. More research would also be required to better understand the relation between floods and the damage they cause for Swedish conditions. / I takt med klimatförändringarna förutspås extrema regnhändelser med stora regnmängder och hög intensitet att öka i framtiden. Samtidigt väljer allt fler människor att flytta från landsbygden in till städerna vilket bidrar till att exponering av sårbara värden som människor, infrastruktur och verksamheter koncentreras. Det i sin tur innebär att risken för översvämning ökar, då översvämningarna förväntas ske mer frekvent samtidigt som risken för att konsekvenser uppstår till följd av översvämningen ökar. För att förebygga översvämningar eller minska risken i framtiden krävs en hållbar stadsplanering, där första steget är att försöka estimera översvämningsrisken inom ett område. Uppskattning av översvämningsrisken är komplicerat. Dels eftersom i) definitionen och kunskapen av risk varierar mycket, ii) det råder stor brist på data och iii) planering och beslut görs flera år i förväg, samtidigt som det är svårt att förutsäga hur städerna kommer att utvecklas. I en ekonomisk riskanalys av översvämningar uttrycks risken i monetära termer som i denna rapport definierats som förväntad årlig skada (Expected Annual Damage, EAD). För att beräkna den verkliga risken för ett område, EAD, för ett visst år måste man beräkna alla konsekvenser för ”alla” händelser. På grund av dagens tekniska begränsningar är det inte möjligt att beräkna alla sannolika händelser på ett effektivt sätt vilket gör det både tidskrävande och dyrt. Syftet med denna rapport är därför bland annat att ge en bättre förståelse för hur ett urval av händelser kan göras för att ändå ge en bra uppskattning. En del av masteruppsatsen bestod i att kartlägga översvämningsrisken i staden Tierp, Sverige. Översvämningsrisken simulerades genom hydrodynamisk modellering med hjälp av 2D-modelleringsprogrammet MIKE 21, utvecklat av DHI. Med hjälp av modellen simulerades den framtida översvämningsutbredningen år 2100 vid nederbörd med återkomsttiderna 1, 2, 5, 10, 20, 30, 50, 100, 200 och 500 år, med en klimatfaktor på 1,25. De ekonomiska konsekvenserna utvärderades i DHI-programmet City Adaptation Decision Support System (CADSS) där översvämningskartor jämfördes med kategoriserade byggnader och dess respektive förväntade skadekostnader. Med hjälp av CADSS kunde översvämningsrisken i form av EAD beräknas, och kombinationen av olika återkomstperioder vid beräkningen av EAD kunde bedömas för att se hur det påverkar resultatet. Utöver detta implementerades hållbara skyfallslösningar i den hydrodynamiska modellen och en hydroekonomisk analys utfördes genom en kostnads-nyttoanalys för att hitta den optimala designåterkomsttiden för lösningarna. Bedömningen av översvämningsriskerna visade att Tierp skulle drabbas av en EAD på 4 304 181 SEK år 2100 om de förväntade klimatförändringarna visar sig vara korrekta. Noggrannheten i EAD-beräkningen visade sig öka med antalet inkluderade återkomsttider, där inkluderandet av lägre återkomsttider visade sig ha en större inverkan på resultatet jämfört med högre återkomsttider. Den hydroekonomiska optimeringen av begränsningsstrukturer ledde till slutsatsen att den optimala återkomstperioden är 50 år, och att nyttan av att införa skyfallslösningar dimensionerade för större återkomsttider är minimal. Fler dimensioner måste dock inkluderas i optimeringen för att bekräfta detta resultat.  Bedömningar av översvämningsrisker har en stor potential att användas som beslutsstöd i Sverige, men bristen på nationella uppgifter om skadekostnader gör resultatet osäkert och svårt att validera. Det krävs även mer forskning för att bättre förstå relationen mellan översvämningar och de skador de orsakar för svenska förhållanden.

Household flood risk mitigation is an important component of Integrated Flood Risk Management. Voluntary household decisions about whether or not to structurally mitigate or insure can directly and indirectly influence vulnerability to the flooding of a community. Serious games can augment existing data collection methods in the flood risk context by operating in the space in between stated and revealed preference, through observing decisions as opposed to asking abstract hypothetical questions, while allowing for complete control over experimental conditions. We look to answer the question of which individual and contextual factors contribute to the decision to mitigate against floods. We gather household decision-making data using a serious game role-play experiment named the Decision Game. Participants spent about 20 minutes making decisions about where to live and how to distribute limited income, given geographical information, including flood risk, about the city. We use a generalized linear mixed modelling approach to analyze the data. Among other findings, we see that experiencing an in-game flood had a strong positive effect, compared to a much weaker effect of a participant having experienced a real-life flood; our key observation is that incentivizing flood risk mitigation should be done quickly following a flood event. We find that real-life low-income individuals were no less likely to implement in-game mitigation measures than their higher-income counterparts, suggesting that subsidies to address an income barrier may be an effective method of encouraging low-income household mitigation. We apply the model to a case study of Calgary, Alberta finding that the insurance market could maintain cross-subsidization after a flood, making insuring higher risk areas more feasible. Moreover, we find that Calgarian policymakers should be encouraged to limit subsidy coverage to high-risk areas to avoid inefficient use of funds in low-risk areas which were projected to have the clear majority of program uptake. / Thesis / Master of Science (MSc) / We develop a research tool to help understand what drives people to protect themselves against flooding. This tool is a computer-based role-playing game experiment in which people take on the role of a homeowner tasked with choosing where to live and how to distribute their income. We log the decisions that people make in the game and use statistical analysis to figure out which factors are important in driving the decisions to insure against floods and to invest in protective structural measures. We find that experiencing a flood in the game has the largest positive effect on these decisions. The results of the model are used to inform a case study where we investigate potential outcomes of policy decisions in Calgary, Alberta. The development of this research tool and the findings contributes to optimizing policies to improve flood risk management through household interventions.

Recentes catástrofes provocadas por eventos hidrológicos extremos ocorridos nas cidades brasileiras revelaram a fragilidade das atuais políticas empregadas no tratamento do problema das inundações. Freqüentemente, faltam recursos mesmo para as ações emergenciais, e as ações estruturais aplicadas muitas vezes consistem de medidas pontuais e paliativas que não promovem soluções definitivas no âmbito de bacia hidrográfica. O tratamento do problema de inundações de maneira orientada ao risco, em lugar da tradicional abordagem orientada a evento, é uma alternativa que propicia soluções mais eficientes e sustentáveis. A gestão do risco de desastres naturais compreende três níveis: antes, durante e após o evento extremo, com base em ações que visam à redução do risco por meio de suas três componentes: ameaça, vulnerabilidade e exposição. No contexto do desenvolvimento e fortalecimento econômico do Brasil, os seguros para desastres naturais têm papel importante como agentes de transferência do risco que possibilitam a recuperação econômica das áreas atingidas. Vencido o entrave inicial à implantação de seguros deste tipo no Brasil, que foi a abertura, em 2007, ao mercado ressegurador internacional, o desafio que se apresenta atualmente é o desenvolvimento de metodologias que possibilitem relacionar a magnitude do evento natural extremo com o prejuízo monetário correspondente e o prêmio de seguro que possibilite ressarcir as perdas contabilizadas, considerando cenários de longo prazo. O modelo de seguros proposto neste trabalho é baseado no princípio de seguro indexado, em que o pagamento de indenizações é vinculado a uma variável climática, no caso, a vazão máxima de cheia. Foram utilizadas ferramentas de modelagem e simulação hidráulico-hidrológica para gerar mapas de risco de inundação e quantificar os prejuízos correspondentes às cheias de diferentes probabilidades de ocorrência. Em seguida, foi simulado um modelo econômico de seguros para obter o prêmio ótimo capaz de ressarcir os prejuízos estimados, considerando diferentes cenários de longo prazo. Um estudo de caso ilustra a aplicação do método em uma bacia hidrográfica caracterizada por problemas recorrentes de inundação, dado o processo de expansão urbana que nela vem ocorrendo. Foram avaliadas faixas de cobertura em função dos períodos de retorno das cheias correspondentes. Os resultados mostraram que a metodologia é adequada à análise do comportamento do fundo de seguros. Resseguros podem ser requeridos para o tratamento de eventos de períodos de retorno muito extremos. / Recent disasters caused by extreme hydrological events, occurred in Brazilian cities, have exposed how fragile the current policies are to manage such situation. Often, a lack of resources is observed even for emergency actions, while structural actions commonly consist of palliative and punctual measures that do not promote real solutions considering the watershed sphere. To face the problem based on a risk-oriented approach instead of the traditional event-oriented approach represents an alternative that provides more efficient and sustainable solutions. Disaster risk management comprehends three time-oriented phases: before, during and after the extreme event, each phase focusing on the three risk\'s components: hazard, vulnerability and exposition. As Brazil\'s economy grows stronger and more stable, natural disaster insurance plays an important role as a risk transfer mechanism, promoting economic resilience in damaged areas. After the opening of the reinsurance\'s market in 2007, Brazil\'s challenge is to develop methodologies relating extreme events hazard with its corresponding damage and an insurance premium, in a way that the losses can be refunded in long term sceneries. The insurance model proposed in this work is based on the indexed insurance, where the refunds are linked to a weather variable - the maximum discharge. Hydrologic and hydraulic simulations were developed in order to generate risk maps and to quantify the damage related to floods with different return periods. Afterwards, a flood insurance model was simulated in order to obtain the optimal insurance premium sufficient to refund the expected damage for long term sceneries. A case study illustrates the method in a watershed where flood events are frequent due to urban occupation. The insurance coverage associated to each flood return period was examined and the results have shown that the methodology is suitable for the analysis of the flood insurance\'s behavior. Reinsurance may be required to deal with extreme events with high return periods.

Recentes catástrofes provocadas por eventos hidrológicos extremos ocorridos nas cidades brasileiras revelaram a fragilidade das atuais políticas empregadas no tratamento do problema das inundações. Freqüentemente, faltam recursos mesmo para as ações emergenciais, e as ações estruturais aplicadas muitas vezes consistem de medidas pontuais e paliativas que não promovem soluções definitivas no âmbito de bacia hidrográfica. O tratamento do problema de inundações de maneira orientada ao risco, em lugar da tradicional abordagem orientada a evento, é uma alternativa que propicia soluções mais eficientes e sustentáveis. A gestão do risco de desastres naturais compreende três níveis: antes, durante e após o evento extremo, com base em ações que visam à redução do risco por meio de suas três componentes: ameaça, vulnerabilidade e exposição. No contexto do desenvolvimento e fortalecimento econômico do Brasil, os seguros para desastres naturais têm papel importante como agentes de transferência do risco que possibilitam a recuperação econômica das áreas atingidas. Vencido o entrave inicial à implantação de seguros deste tipo no Brasil, que foi a abertura, em 2007, ao mercado ressegurador internacional, o desafio que se apresenta atualmente é o desenvolvimento de metodologias que possibilitem relacionar a magnitude do evento natural extremo com o prejuízo monetário correspondente e o prêmio de seguro que possibilite ressarcir as perdas contabilizadas, considerando cenários de longo prazo. O modelo de seguros proposto neste trabalho é baseado no princípio de seguro indexado, em que o pagamento de indenizações é vinculado a uma variável climática, no caso, a vazão máxima de cheia. Foram utilizadas ferramentas de modelagem e simulação hidráulico-hidrológica para gerar mapas de risco de inundação e quantificar os prejuízos correspondentes às cheias de diferentes probabilidades de ocorrência. Em seguida, foi simulado um modelo econômico de seguros para obter o prêmio ótimo capaz de ressarcir os prejuízos estimados, considerando diferentes cenários de longo prazo. Um estudo de caso ilustra a aplicação do método em uma bacia hidrográfica caracterizada por problemas recorrentes de inundação, dado o processo de expansão urbana que nela vem ocorrendo. Foram avaliadas faixas de cobertura em função dos períodos de retorno das cheias correspondentes. Os resultados mostraram que a metodologia é adequada à análise do comportamento do fundo de seguros. Resseguros podem ser requeridos para o tratamento de eventos de períodos de retorno muito extremos. / Recent disasters caused by extreme hydrological events, occurred in Brazilian cities, have exposed how fragile the current policies are to manage such situation. Often, a lack of resources is observed even for emergency actions, while structural actions commonly consist of palliative and punctual measures that do not promote real solutions considering the watershed sphere. To face the problem based on a risk-oriented approach instead of the traditional event-oriented approach represents an alternative that provides more efficient and sustainable solutions. Disaster risk management comprehends three time-oriented phases: before, during and after the extreme event, each phase focusing on the three risk\'s components: hazard, vulnerability and exposition. As Brazil\'s economy grows stronger and more stable, natural disaster insurance plays an important role as a risk transfer mechanism, promoting economic resilience in damaged areas. After the opening of the reinsurance\'s market in 2007, Brazil\'s challenge is to develop methodologies relating extreme events hazard with its corresponding damage and an insurance premium, in a way that the losses can be refunded in long term sceneries. The insurance model proposed in this work is based on the indexed insurance, where the refunds are linked to a weather variable - the maximum discharge. Hydrologic and hydraulic simulations were developed in order to generate risk maps and to quantify the damage related to floods with different return periods. Afterwards, a flood insurance model was simulated in order to obtain the optimal insurance premium sufficient to refund the expected damage for long term sceneries. A case study illustrates the method in a watershed where flood events are frequent due to urban occupation. The insurance coverage associated to each flood return period was examined and the results have shown that the methodology is suitable for the analysis of the flood insurance\'s behavior. Reinsurance may be required to deal with extreme events with high return periods.

Flooding is an important concern for the UK, as evidenced by the many extreme flooding events in the last decade. Improved flood risk intervention strategies are therefore highly desirable. The application of hydroinformatics tools, and optimisation algorithms in particular, which could provide guidance towards improved intervention strategies, is hindered by the necessity of performing flood modelling in the process of evaluating solutions. Flood modelling is a computationally demanding task; reducing its impact upon the optimisation process would therefore be a significant achievement and of considerable benefit to this research area. In this thesis sophisticated multi-objective optimisation algorithms have been utilised in combination with cutting-edge flood-risk assessment models to identify least-cost and most-benefit flood risk interventions that can be made on a drainage network. Software analysis and optimisation has improved the flood risk model performance. Additionally, artificial neural networks used as feature detectors have been employed as part of a novel development of an optimisation algorithm. This has alleviated the computational time-demands caused by using extremely complex models. The results from testing indicate that the developed algorithm with feature detectors outperforms (given limited computational resources available) a base multi-objective genetic algorithm. It does so in terms of both dominated hypervolume and a modified convergence metric, at each iteration. This indicates both that a shorter run of the algorithm produces a more optimal result than a similar length run of a chosen base algorithm, and also that a full run to complete convergence takes fewer iterations (and therefore less time) with the new algorithm.

京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第13278号 / 論工博第4181号 / 新制||工||1726(附属図書館) / (主査)教授 角 哲也, 教授 寶 馨, 准教授 Sameh Kantoush, 教授 立川 康人 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The development of suitable long term flood risk intervention strategies is a challenge. Climate change alone is a significant complication but in addition complexities exist trying to identify the most appropriate set of interventions, the area with the highest economical benefit and the most opportune time for implementation. All of these elements pose difficulties to decision makers. Recently, there has been a shift in the current practice for appraising potential strategies and consideration is now being given to ensure flexible, adaptive strategies to account for the uncertain climatic conditions. Real Options in particular is becoming an acknowledged approach to account for the future uncertainties inherent in a flood risk investment decision. Real Options facilitates adaptive strategies as it enables the value of flexibility to be explicitly included within the decision making process. Opportunities are provided for the decision maker to modify and update investments when knowledge of the future state comes to light. In this thesis the use of Real Options in flood risk management is investigated as a method to account for the uncertainties of climate change. Each Intervention strategy is purposely designed to capture a level of flexibility and have the ability to adapt in the future if required. A state of the art flood risk analysis tool is employed to evaluate the risk associated to each strategy over future points in time. In addition to Real Options, this thesis also explores the use of evolutionary optimisation algorithms to aid the decision making process when identifying the most appropriate long term strategies. Although the risk analysis tool is capable of quantifying the potential benefits attributed to a strategy, it is not necessarily able to identify the most appropriate. Methods are required which can search for the optimal solutions according to a range of performance metrics. Single and multi-objective genetic algorithms are investigated in this thesis as a method to search for the most appropriate long term intervention strategies. The Real Options concepts are combined with the evolutionary multiobjective optimisation algorithm to create a decision support methodology which is capable of searching for the most appropriate long term economical yet robust intervention strategies which are flexible to future change. The methodology is applied to two individual case studies, a section of the Thames Estuary and an area on the River Dodder. The results show the inclusion of flexibility is advantageous while the outputs provide decision makers with supplementary knowledge which previously has not been considered.

Despite considerable uncertainties regarding the exact contribution of anthropogenic climate change to disaster risk, rising losses from extreme events have highlighted the need to comprehensively address climate-related risk. This requires linking climate adaptation to disaster risk management (DRM), leading to what has been broadly referred to as climate risk management (CRM). While this concept has received attention in debate, important gaps remain in terms of operationalizing it with applicable methods and tools for specific risks and decision-contexts. By developing and applying a methodological approach to CRM in the decision context of sovereign risk (flooding) in Austria we test the usefulness of CRM, and based on these insights, inform applications in other decision contexts. Our methodological approach builds on multiple lines of evidence and methods. These comprise of a broad stakeholder engagement process, empirical analysis of public budgets, and risk-focused economic modelling. We find that a CRM framework is able to inform instrumental as well as reflexive and participatory debate in practice. Due to the complex interaction of social-ecological systems with climate risks, and taking into account the likelihood of future contingent climate-related fiscal liabilities increasing substantially as a result of socioeconomic developments and climate change, we identify the need for advanced learning processes and iterative updates of CRM management plans. We suggest that strategies comprising a portfolio of policy measures to reduce and manage climate-related risks are particularly effective if they tailor individual instruments to the specific requirements of different risk layers. (authors' abstract)