Comparing potential for storm water control of different full-scale blue roofs by field experiments

Sustainable urban drainage systems are considered a viable option to improve the resilience of cities against flooding. Among such systems, blue roofs are receiving growing interest for managing stormwater runoff directly on building rooftops. The paper discusses the results of field experiments aimed at monitoring the hydrological behaviour of three different full-scale blue roof systems. The experiments were carried out in Catania (Italy) over a 15-month-long period between September 2021 and November 2022. The three installations were constructed using i) modular trays, ii) rugs of artificial turf, and iii) a cover layer made of pebbles. Highest performances were obtained with the modular blue roof, with mean 53% runoff reduction and mean 67% flow peak attenuation. The blue roof system made with rugs of artificial turf revealed a mean 31% runoff reduction and 51% peak attenuation while the blue roof system with pebbles layer showed the lowest retention and detention efficiencies (both 24%).