Modelling of green roof hydrological performance for urban drainage applications

The Influence of Hydrologic Parameters on the Hydraulic Efficiency of an Extensive Green Roof in Mediterranean Area

“…Many studies agree that the green roofs influence runoff hydrographs, especially by delaying the runoff peak. Locatelli et al [20] have noted that the delay of the peak flow rate was up to 40 min, while Getter et al [10] and Villarreal and Bengtsson [25] have found minimal delays. However, for the majority of studies the delay of the peak flow rate was found to be up to 30 min [12,23].…”

“…As previously mentioned, literature studies have shown that green roofs have a positive effect on the reduction of stormwater runoff [12,15,16,[19][20][21][22][23]. The water retention capacity mainly depends on the physical features of the green roof (number of layers and materials, soil type and thickness, type of vegetation and percentage of roof covered, roof geometry), and the weather conditions (length of antecedent dry weather period, season/climate, characteristics of rain event like intensity and duration) [14].…”

“…Locatelli et al [20], by analyzing three different extensive green roofs in Denmark, have implemented a model to quantify the hydrological response of the green roofs based on 22 years of observations. The average subsurface runoff coefficient obtained was between 0.43 and 0.68.…”

“…[34] Mediterranean-Genova (IT) 0.48 Voyde et al (2010) [15] Sub-tropical-Auckland (NZ) 0.34 Stovin et al (2012) [16] Temperate-Sheffield (UK) 0.48 Gromaire et al (2013) [19] Temperate-Trappes (F) 0.36-0.50 Locatelli et al (2014) [20] Ocean-Odense and Copenaghen (DK) 0.43-0.68 Wong and Jim (2014) [35] Humid sub-tropical-Hong Kong (CN) 0.86-0.89…”

“…The definition of such coefficient is crucial for designing purposes and, therefore, it has to be properly defined. Although many studies have analyzed the subsurface runoff coefficient for few selected events and shown its broad variability, a systematic statistical analysis has never been carried out in Mediterranean climate conditions [16][17][18][19][20].…”