Impacto dos telhados verdes na mitigação do escoamento superficial em loteamentos residenciais de Teresina-PI

Abstract

Teresina, capital of the state of Piauí, faces extreme climate changes that aggravate its social, environmental and economic vulnerabilities. The waterproofing of a large part of its urban site, combined with a deficient infrastructure, resulted in the worsening of disasters during floods and rainfall. In view of this, new approaches focused on sustainability have been applied, such as Low Impact Development (LID) and Water Sensitive Urban Design (WSUD). The LID model proposes the use of compensatory techniques as mitigating actions against the harmful effects of urbanization on the hydrological cycle, reducing peak flow rates in rainfall and surface runoff in surrounding areas. Among these techniques, green roofs have been standing out, as their insulating layers contribute to the thermal performance of buildings, a decisive factor in regions with high temperatures, especially in urban centers affected by heat islands. In this sense, the present work evaluated the application of green roofs in sustainable drainage systems for residential subdivisions in Teresina-PI, through computational modeling in the Storm Water Management Model (SWMM), emphasizing its hydrological performance and its economic viability of implementation through cost compositions. After analyzing the computational model in scenarios of 25% and 100% conversion of the roof area, reductions in peak flow and surface runoff of the microbasin were observed proportional to the increase in the application area, reaching up to 35.94% and 31.40% respectively, compared to the scenario without application of these devices. However, it was found that the cost required for its construction had increased by more than twice, based on traditional fiber cement tile roofing techniques originally proposed for the study area. Therefore, it can be inferred that, despite the significant contribution of green roofs to the hydrological performance of the region, it is essential to adopt measures that aim to make costs more accessible and encourage market training so that their use is viable, in order to promote a sustainable city.