Jardins de chuva: uma análise teórica e experimental para a implementação no Brasil

Abstract

The green infrastructure Rain Garden aims to reduce the impacts of urbanization on urban waters and adapt cities to climate change. This thesis aimed to evaluate its applicability in Brazilian cities. The work was subdivided into three chapters. In the first chapter, a theoretical framework of the rain garden's functionality was developed through a systematic review. In the second chapter, a practical framework was conducted to analyze the methodologies used to assess the garden's functionality by examining a rain garden installed in the city of Rio de Janeiro, RJ. The rational method, a pluviograph, and computational modeling using Hydrus-1D were employed to measure the rainwater retention capacity. Additionally, samples were collected from direct precipitation, first flush water, and water that passed through the rain garden to evaluate its pollutant retention capacity. In the third chapter, a propositional analysis was performed to understand the challenges in disseminating the technique in Brazil and propose solutions. Questionnaires were administered to specialists, and research on national and international legislation and programs related to the dissemination of the technique was conducted. The studies found were categorized into five main topics: pollution control, operational improvement, water retention capacity, installation costs, and socio-environmental factors. The assessment of efficiency and the costs of installation and maintenance are the most current topics. The rain garden did not overflow during the study period, and although it occupied 11% of the water catchment area, it would still be functional with an area equivalent to 6.3% of the rooftops. Regarding pollutant removal, there was a reduction of 73% in fecal coliforms, 39% in total dissolved solids, and 12.1% in total organic carbon in runoff water. In terms of the popularity of green infrastructure, green roofs are the most well-known, and the lack of awareness, along with the absence of a construction standard, appears to be a significant barrier to the dissemination of the rain gardem technique. Current legislation does not yet cover rain gardens, and fragmented governance in the management of urban rivers and drainage systems also emerged as a barrier in Brazil. Rain gardens can be an essential tool for adapting cities to climate change and revitalizing urban rivers. Greater dissemination of the technique, capacity building for involved stakeholders, implementation of legal instruments, and public incentives for the installation of green infrastructure by urban populations are necessary.