Vegetation Survival in Green Roofs without Irrigation

The Sustainable Urban Drainage Systems on stormwater management provide benefits for sewer networks, treatment plants and environment and should be encouraged. Green roofs are part of these systems and can contribute both to delay and cut peak runoff and reduce discharged volumes. In this paper the probability of vegetation survival without irrigation has been proposed as a guide to operators on selecting vegetation and irrigation system as well as design parameters. An analytical probabilistic approach has been proposed; a chain of consecutive rainfall events has been considered to take into account the possibility that storage capacity is not completely available at the beginning of the considered event but pre-filled from previous rainfalls, as typical of green roofs. Finally, an application to a case study has been proposed to validate proposed equations.