Thermal and hydrological performance of extensive green roofs in Amazon climate, Brazil

Improper urban planning has been proven to produce excessive environmental impacts in urban areas, such as urban flooding and urban heat islands. A new approach to protecting the urban environment brought forward the idea of low-impact urban development, which uses rainwater-control devices such as cisterns, permeable pavements and green roofs. This study aimed to evaluate the potential of green roofs in two important environmental dimensions: thermal and hydrological. An experimental study was conducted at the Federal University of Para Guama Campus, Belem, Brazil. Hydrological and thermal data from a green roof and a fibre-cement roof were collected and compared to analyse the performance of the roofs. The results showed extensive green roofs to be an effective tool for reducing rainfall run-off at the roof scale, particularly for small-storm events, as well as an efficient thermal roof insulation.