A conceptual model for predicting hydraulic behaviour of a green roof

In urban environment green roof represents a sustainable solution for mitigating rainfall-runoff volumes delivered to combined sewer systems. Despite numerous studies have been focusing on long-term monitoring of green roof in urban watersheds, few literature has analysed and built models for predicting the hydraulic efficiency of a green roof. This study proposes a conceptual model to predict the hydraulic behaviour of a small-scale physical model of a green roof. The model green roof is idealized as a system consisting of three individual components in series. Each component is subjected to different hydrologic and hydraulic processes and therefore, is treated as a separate module. A mass balance equation is applied to each component, taking into account the specific phenomena occurring in each module. The model is loaded by a series of constant rainfall intensities. The physical model testing is also performed. Results demonstrate the model is accurately able to predict the hydraulic behaviour of the system as compared to measured data. In future research study this model will be applied to long-term basis simulation. (C) 2013 The Authors. Published by Elsevier Ltd.