Nilo de Oliveira Nascimento

Streamflow estimates are necessary for devising effective flood management strategies in urban areas. However, rating curves (RC), which formally summarize stage-discharge relationships, are rarely available, mainly because of difficulties in measuring flow velocities in such environments. As a result, in the absence of gaugings, researchers and practitioners frequently resort to simplified hydraulic approaches for computing flood discharges, which renders validation and uncertainty assessment in flood-related studies unfeasible. In this paper, we explore a Bayesian framework that combines empirical information on stages and expert prior hydraulic knowledge for indirectly estimating rating curves from rainfall-runoff (RR) simulations. We investigate advantages and drawbacks of the proposed rainfall-stage model in a Brazilian urban catchment, in which 25 gaugings, which were not utilized in inference, are available for model scrutiny. Our results demonstrate that, although deriving a synthetic RC was feasible, uncertainty in stage predictions was too large. However, the explicit treatment of RC and RR errors allowed estimating true discharges, which is useful for flood routing along the river reach. Overall, the synthetic RC provided physical realism to the stage-discharge relationship. Yet, the rainfall-stage model was strongly affected by the lack of gaugings, which suggests actual monitoring should be highly beneficial for decision making.

The UN's New Urban Agenda has penetrated urban planning at the same time as extreme events caused by climate change. In view of the scenario of increased flooding in Belo Horizonte, state of Minas Gerais, the Master Plan approved instruments to mitigate the impacts through discounts on the fees charged for additional building rights for new buildings that use “green and blue infrastructure.” The applicability of this incentive is analyzed across the territory based on a comparison between the discounts and the costs of new sustainable techniques. It is concluded that the instruments tend to be adopted where land value is higher, being insufficient for a large part of the city, mainly areas with greater climate vulnerability, which demand more direct interventions from the government.

Resumo A Nova Agenda Urbana da ONU penetra o planejamento urbano ao mesmo tempo que eventos extremos causados pelas mudanças climáticas. Diante do cenário de intensificação de inundações em Belo Horizonte – MG, o Plano Diretor aprovou instrumentos para mitigar tais impactos. por meio de descontos na Outorga Onerosa do Direto de Construir para novas edificações que utilizem “infraestruturas verdes e azuis”. Analisa-se a aplicabilidade desse incentivo pelo território, com base na comparação entre esses descontos e os custos das novas técnicas sustentáveis. Conclui-se que os instrumentos tendem a ser adotados onde o solo é mais valorizado, sendo insuficientes para grande parte da cidade, em especial as áreas de maior vulnerabilidade climática, que demandam intervenções mais diretas do poder público.