Spatiotemporal distribution of hydrological extremes in Brazil

To reduce the future negative impacts of hydrological extremes, it is crucial to understand the spatiotemporal variability of flood and drought hazard and social, economic, and environmental vulnerabilities. Such understanding is particularly important in developing countries which are strongly vulnerable to hydrological extremes because of greater economic dependence on climate-sensitive primary activities and infrastructure. Brazil is increasingly affected by hydrological extreme events and related losses. The sum of damages and losses caused by recurrent floods and droughts has a substantial impact, especially in small and medium-sized municipalities. Developing disaster resilience and adaptation strategies requires an understanding of the risks related to floods and droughts and how they are spatially distributed and related across the country. Therefore, we present a risk analysis of how floods and drought are distributed and spatially connected across Brazil. To assess flood hazard, we rely on frequency analysis and spatial dependence measures. Moreover, the vulnerabilities towards drought and flood hazard were derived using data from the Brazilian atlas of natural disaster: damages and losses($), people affected, deaths, and homelessness. Based on the results, we divide the country into regions suitable to risk pooling, i.e. groups of municipalities that can cooperatively share costs, liabilities and risks.These regions can implement adaptation measures at the regional level, i.e. flood-drought risk insurance framework, using conjugate return periods, extended losses, multi-risk coverage, and composite willingness to pay and adapt. Our risk analysis will support the development of adaptation plans to hydrological extremes at the catchment and regional scale.