Análise comparativa da retenção hídrica e coeficiente de Runoff entre cobertura convencional e telhado verde com geocomposto drenante

Abstract

Accelerated urbanization promotes soil impermeabilization, leading to the overloading of drainage systems and an increase in flooding events. As a compensatory measure, green roofs emerge as an effective solution for rainwater retention at the source. This study aimed to evaluate the hydrological performance of an extensive green roof, constructed with geosynthetics, in comparison to a conventional roofing system. The methodology involved rainfall simulation tests with a critical intensity of 116.20 mm/h performed on 1.155 m² test modules. The Runoff Coefficient (C), retained volume, and runoff delay time were analyzed. The results demonstrated that the green roof reduced the Runoff Coefficient from 0.976 (conventional) to 0.826, providing water retention of 17.4% of the total precipitated volume. Furthermore, the system promoted an average delay in the start of runoff of 3 minutes and 48 seconds, an increase of nearly seven times compared to the conventional module (34 seconds). The geosynthetics used (geomembrane, drainage geocomposite) validated their technical functionality, ensuring the system’s watertightness and filtration. It is concluded that the extensive green roof is a viable and efficient alternative for mitigating peak flow in urban areas, such as the municipality of Rio Verde/GO.