Using historical source data to understand urban flood risk: a socio-hydrological modelling application at Gregorio Creek, Brazil

This is an Accepted Manuscript of an article published by Taylor & Francis in Hydrological Sciences Journal on [date of publication], available online: https://doi.org/10.1080/02626667.2020.1740705.The city of São Carlos, state of São Paulo, Brazil, has a historical coexistence between society and floods. Unplanned urbanization in this area is a representative feature of how Brazilian cities have developed, undermining the impact of natural hazards. The Gregório Creek catchment is an enigma of complex dynamics concerning the relationship between humans and water in Brazilian cities. Our hypothesis is that social memory of floods can improve future resilience. In this paper we analyse flood risk dynamics in a small urban catchment, identify the impacts of social memory on building resilience and propose measures to reduce the risk of floods. We applied a socio-hydrological model using data collected from newspapers from 1940 to 2018. The model was able to elucidate human–water processes in the catchment and the historical source data proved to be a useful tool to fill gaps in the data in small urban basins

Anticipated Memories and Adaptation from Past Flood Events in Gregório Creek Basin, Brazil

From MDPI via Jisc Publications RouterHistory: accepted 2021-11-23, pub-electronic 2021-12-01Publication status: PublishedIn this research we used walking interviews to investigate the measures used by shopkeepers as protection against floods. The concept of anticipated memory has been used to identify the relationship between their learning from previous events and the adaptive measures they have taken to reduce risk of future flooding in Gregório Creek basin. The area is affected by major flooding issues in the city of São Carlos, southeastern Brazil. Twenty-three (23) downtown merchants shared their experience of the extreme rainfall that occurred on 12 January 2020, characterized by a return period of 103 years. Comparing our findings with November 2015 and March 2018 floods (Interviews 37 and 52 respectively), we noted that due to the enhanced level of threat, people had changed their adaptation strategy by increasing the sum of floodgate height more than 4-fold (870 cm to 3830 cm) between 2015 to 2020. Our results showed that despite frequent flooding, the shopkeepers downtown were reluctant to move away from the area; rather, they preferred to improve their individual protection. The substantial increase in the height of the floodgates represents the population’s feedback in the face of a new level of threat

Panta Rhei benchmark dataset: socio-hydrological data of paired events of floods and droughts

As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e., two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed, and in the quantity of socio-hydrological data. The benchmark dataset comprises: 1) detailed review style reports about the events and key processes between the two events of a pair; 2) the key data table containing variables that assess the indicators which characterise management shortcomings, hazard, exposure, vulnerability and impacts of all events; 3) a table of the indicators-of-change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators-of-change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses e.g. focused on causal links between risk management, changes in hazard, exposure and vulnerability and flood or drought impacts. The data can also be used for the development, calibration and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al. 2023, link for review: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/).</p

Escalas espaciais e temporais da interação homem-água frente ao risco de seca em megacidades: uma abordagem sócio-hidrológica em São Paulo

The Sao Paulo Metropolitan Region hosts more than 20 million inhabitants, who are supplied by several water sources wherein the Cantareira System, one of the largest water supply reservoirs in the world, is capable to deliver more than 30 m3/s of water. The reduced rainfall observed in 2013 and 2014 triggered the most severe water crisis in its recent history and raised several questions about the hazard intensity, the decision makers\' ability to handle with such events and the community role in reducing the water consumption when required. This thesis aims at investigating the interactions over time between water availability and human action in Sao Paulo to assess whether the crisis resulted from this drought event could have been avoided. First, historic records and key aspects related to drought risk management, such as hazard intensity, preparedness, exposure, vulnerability, disaster response and mitigation alternatives, are used to compare the 2013-2015 water crisis to the 1985-1986 drought, observed long ago, and contrast the evolution of those aspects so far. Therefore, the evidence suggests the greater hazard intensity and people\'s exposure to drought, in combination to both late water-saving policies\' implementation and the dependency of several service areas on a single reservoir, culminated in the disaster experienced in 2013-2015. Second, a machine learning model is employed to address the community response to water saving policies and to outline a hypothetical storyline considering the early implementation of such policies. The model outputs suggest stronger significance on the contingency tariff rather than the bonus tariff. Therefore, the penalty tariff would be required two years in advance to promote water conservation of local users and prevent the Cantareira System from reaching the dead pool level. Third, the water allocation from the Paraiba do Sul River Basin is evaluated upon the scenarios of transboundary interactions between upstream &#8211; Sao Paulo State &#8211; and downstream &#8211; Rio de Janeiro State &#8211; within the context of the 2013-2015 water crisis. Those scenarios address the impacts of i) water allocations from the Paraiba do Sul River Basin to the Cantareira System through a tunnel concluded after the drought, and ii) updated operation rules of the Paraiba do Sul River Basins as a response to drought impacts within its basin observed in 2013-2015 as well. The three scenarios show that the impacts on water availability and hydropower production does not satisfy the two players at the same time and, therefore, put then in a game where hydroelectricity would be reduced for both states at any scenario, while the water transfers to Sao Paulo would be equivalent to the supply of 1 million people downstream in the three years. The three working fronts explore the two-way feedbacks between water availability and humans\' behavior to better understand the coevolution of this coupled system in Sao Paulo and outline hypothetical storylines to improve the responses of futures drought events.A Região Metropolitana de São Paulo abriga mais de 20 milhões de habitantes que são abastecidos por diversas fontes de água, onde o Sistema Cantareira, um dos maiores sistemas de reservatórios de abastecimento de água do mundo, é capaz de fornecer mais de 30 m3/s de água. A redução das chuvas observada em 2013 e 2014 desencadeou a mais grave crise hídrica de sua história recente e levantou diversas questões sobre a intensidade do evento, a capacidade dos tomadores de decisão para lidar com tais eventos e o papel da comunidade na redução do consumo de água quando necessário. Desta maneira, esta tese objetiva investigar as interações ao longo do tempo entre a disponibilidade de água e a ação humana, em São Paulo, para avaliar se a crise decorrente do evento de seca poderia ter sido evitada. Primeiro, revisita-se registros históricos e compara-se a crise hídrica de 2013-2015 com a seca de 1985-1986 para avaliar a evolução de aspectos-chave relacionados ao gerenciamento de risco de seca, como intensidade do evento, preparação, exposição, vulnerabilidade, resposta ao desastre e ações de mitigação. Assim, as evidências observadas sugerem que a maior intensidade do evento e a maior exposição das pessoas à seca, em combinação com a implementação tardia de políticas de redução do uso da água e a dependência de várias áreas de abastecimento em um único reservatório culminaram no desastre ocorrido em 2013-2015. Na sequência, um modelo de aprendizado de máquina aborda a resposta da comunidade às políticas de redução do uso de água para avaliar a eficácia de cenários hipotéticos que consideram a implementação precoce de tais políticas. O modelo sugere mais importância da tarifa de contingência, que aumenta o valor cobrado dos consumidores por não reduzir o uso de água, em relação à tarifa bônus, que reduz a conta de água dos consumidores que voluntariamente diminuem seu consumo. Assim, os resultados apontam que as políticas de redução de consumo seriam necessárias com dois anos de antecedência para promover a conservação da água dos usuários locais e evitar que o Sistema Cantareira atingisse o nível do volume morto. Por fim, as interações transfronteiriças da bacia do Rio Paraíba do Sul entre montante &#8211; Estado de São Paulo &#8211; e jusante &#8211; Estado do Rio de Janeiro &#8211; são exploradas no contexto da mesma crise hídrica de 2013-2015. A construção de cenários aborda os impactos de i) alocações de água da Bacia do Rio Paraíba do Sul para o Sistema Cantareira através de um túnel, que fora concluído apenas após o evento de seca, e ii) as novas regras de operação dos reservatórios, que foram atualizadas em resposta aos impactos da seca observada em 2013-2015. Os cenários mostram que os impactos na disponibilidade de água e na produção de energia hidrelétrica não satisfazem os dois jogadores ao mesmo tempo e, portanto, colocá-los-iam em cenários onde a hidreletricidade seria reduzida para ambos os estados, enquanto a transferência de água para São Paulo seria equivalente ao abastecimento de 1 milhão de pessoas a jusante. Os três estudos exploram os feedbacks bidirecionais entre a disponibilidade de água e as respostas humanas para melhor entender a coevolução desse sistema em São Paulo e avaliar cenários hipotéticos com intuito de estimar as melhores respostas para futuros eventos de seca

Observatório Sócio Hidrológico para Segurança Hídrica: Definições e estudo de caso em São Carlos, Brasil

The need to better comprehend the relationship between societies and the hydrological cycle led scientists to develop sophisticated mathematical models in order to predict how these relationships will be in the future. However, some transformations might not be predicted in such socio-hydrological models, what makes necessary to search for new methods to build scenarios. In this way, the present work seeks to understand how societies will change the way they deal with water resources regarding different drivers of change, such as population growth, changes in climate, land cover, patterns of consumption and influence of governmental institutions. To do so, this work employs not only official data sets that are public available, but also information provided by citizens through citizen observatories concepts of crowdsourcing, participatory governance and environmental monitoring. Such volunteered information is based on their own experiences, knowledge and individual patterns regarding water management and sanitation aspects from the study area, São Carlos city. The conclusions reveal that the new tool presented in this work, the Socio-Hydrological Observatory for Water Security (SHOWS), makes possible to outline future trajectories of coevolution in coupled human-water system and provide assessment on water security scenarios. This work integrates the water security component facing climate changes, from INCT-MC2 (FAPESP 2014/50848-9), contributes to better comprehend socio hydrological aspects in UK Academies (FAPESP 2018/03473-0) and provides a new tool, the SHOWS, which assists decision makers in resilient cities, in the context of CEPID/CEMEAI (FAPESP 2011/51305-0) e do SPRINT-Warwick (FAPESP 2018/08413-6). At international level, it is a contribution to the activities of \"Panta Rhei &#8211; Everything Flows 2013-2022\", promoted by the International Association of Hydrological Sciences, which seeks to understand, estimate and predict the hydrological dynamics to support societies under change.A necessidade de compreender as relações entre as sociedades e o ciclo hidrológico levou cientistas a elaborarem sofisticados modelos matemáticos para prever como estas relações serão no futuro. Porém, determinadas transformações podem não ser previstas nestes modelos sócio-hidrológicos, sendo necessário recorrer a novos métodos para elaborar cenários. Desta maneira, o presente trabalho busca entender como as sociedades irão modificar a maneira que lidam com os recursos hídricos frente aos vetores de mudanças, como crescimento demográfico, alterações climáticas, mudanças do uso e ocupação do solo, influência de instituições governamentais e padrões de consumo da população. Para isto, este trabalho emprega não somente o uso de dados oficiais, disponibilizados em plataformas públicas, mas também as informações fornecidas por cidadãos através dos conceitos dos observatórios cidadãos, como crowdsourcing, governança participativa e monitoramento ambiental. Estas informações voluntárias são baseadas em suas experiências, conhecimentos e padrões individuais em relação a aspectos necessários a gestão dos recursos hídricos e dos sistemas de saneamento da área de estudo, o município de São Carlos. Ao fim, conclui-se que, a partir da ferramenta Observatório Sócio Hidrológico para Segurança Hídrica (SHOWS), é possível interpretar possíveis trajetórias de coevolução entre os sistemas sociais e naturais de maneira a avaliar os cenários de segurança hídrica. Este estudo integra a componente de segurança hídrica frente às mudanças climáticas do INCT-MC2 (FAPESP 2014/50848-9), contribui para a compreensão dos aspectos sócio hidrológicos do UK Academies (FAPESP 2018/03473-0), além de testar uma nova ferramenta, o SHOWS, que serve de auxílio à tomada de decisão em cidades resilientes, no contexto do CEPID/CEMEAI (FAPESP 2011/51305-0) e do SPRINT-Warwick (FAPESP 2018/08413-6). Em âmbito internacional, é uma contribuição às atividades da década científica \"Panta Rhei &#8211; Everything Flows 2013-2022\", promovida pela International Association of Hydrological Sciences, a qual busca entender, estimar e prever dinâmicas hidrológicas para apoiar sociedades sob mudanças

Blue and grey urban water footprints through citizens’ perception and time series analysis of Brazilian dynamics

From Crossref journal articles via Jisc Publications RouterHistory: epub 2021-03-04, issued 2021-03-04Funder: Fundação Amazônia Paraense de Amparo à Pesquisa; FundRef: 10.13039/501100005288; Grant(s): grant no. 2018/08413-6Funder: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; FundRef: 10.13039/501100002322; Grant(s): 88887.091743/2014-01Funder: FAPESP CEPID/CEMEAI; Grant(s): 2011/51305-0Funder: INCT-II [Climate Change, Water Security]Funder: CNPq PQ; Grant(s): 312056/2016-8Funder: (EESC-USP/CEMADEN/MCTIC) and CAPES PROEX [PPGSHS EESC USP]Funder: [ProAlertas CEPED/USP]Funder: CAPES/PNPD; Grant(s): grant 2016-131

The challenge of unprecedented floods and droughts in risk management

International audienceAbstract Risk management has reduced vulnerability to floods and droughts globally 1,2 , yet their impacts are still increasing 3 . An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data 4,5 . On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change 3