The Feasibility of Rainwater Harvesting Systems in Buildings with Green Roofs: A Case Study Based on the Köppen Climate Classification

The construction of green roofs (GR) combined with rainwater harvesting systems (RWHSs) in buildings can increase the advantages of each of these technologies, being a very promising solution to combat climate change and increase the sustainability of cities. However, the viability of this joint solution significantly depends on local climatic conditions. The planet's climate classification, known as the Koppen climate classification, is one of the most widely used climate classification systems. The Koppen climate classification divides climates into five main climate groups, with each group being referenced based on seasonal precipitation and temperature patterns. In the specific case of mainland Portugal, according to the Koppen classification, the climate is divided into two regions. In this article, case studies are developed for two Portuguese climatic regions, seeking to demonstrate the possibility of using the Koppen classification as a decision criterion for the eventual inclusion of rainwater harvesting systems in buildings with green roofs. For this study, the results of a previous study were applied, through which we obtained an expression to determine the runoff coefficients of green roofs common in Portugal, concluding that the Koppen climate classification can be used as a prior decision criterion regarding its incorporation or exclusion in rainwater harvesting system buildings combined with green roofs, depending on the location.