Rainwater recovery rooftop garden and aeroponic greenhouse in Turin

Meet water, meet people, meet plants

PILOT PARTNER: City of Turin

PILOT LOCATION: “Open 011” Youth Hostel, Turin 

The pilot action aims at demonstrating rainwater retention and attenuation by applying different nature-based solutions (NBSs) to deal with rainwater in an urban context. In addition, it will further develop a rooftop farming strategy as a solution for the resilient city of tomorrow. The pilot action will help Turin and other public authorities define innovative “Green and blue infrastructure strategies” to feed the future “Local Environmental Adaptation Plan” of the city of Turin. 



"Meet water, meet people, meet plants" - the model of the new green area

The pilot action is implemented at “Open 011”, a youth hostel built for the 2006 Winter Olympics in Turin in a former 1940’s factory. The building is owned by the City of Turin in a concession with the cooperative DOC (25 years, start 2019). A big south terrace is used as a rooftop garden including an adjacent aeroponic greenhouse, which is irrigated with harvested rainwater. The overflow is diverted into a rain garden planned at the entrance of building. The building is EU ECOLABEL certified and already employs ICT devices to monitor the building’s environmental performance: a temperature monitoring system and a weather station. The pilot action also includes participatory activities with the student's community of the youth hostel, thus promoting and elevating the education and dissemination potentials.


Location of the O11 Youth Hostel in Turin

Harvested rainwater from approx. 325 m² of roof surfaces is reused to irrigate a rooftop garden and a greenhouse aeroponic system, whereas the overflow is diverted to irrigate the rain garden. The annual precipitation in Turin is 993 mm (8-year average).


The youth hostel with roof gutters (blue points) from where rainwater will be collected

The pilot design includes the following components:
- An intensive green roof of approx.180 m²;
- An aeroponic greenhouse for food cultivation;
- A rain garden with a surface area of 21 m² and a storage volume of 10 m³ (corresponding to a rain event of about 20 mm with a return period of 5-10 years) to collect and slowly infiltrate the rainwater overflow.
Rainwater harvested from approx. 230 m² of roof surface will be collected in an underground cistern with a 13 m³ capacity and used to irrigate the green roof. Rainwater from approx. 100 m² of roof surface will be harvested and separately collected in a small rainwater tank (350 l) placed on the terrace to be used for aeroponic irrigation in the greenhouse. Rainwater from the green roof (180 m²) and the overflow of the rainwater storage tank will be fed into the rain garden for infiltration, thus closing the water cycle.

The use of environmental sensors to collect data which will feed the smart data platform already in use in Torino-Yuca (cloud-based, self-service platform) will also be implemented.

Turin building plan

Design plan of site and the adopted nature-based solutions


The expected impacts of the adopted measures include climate change adaptation and flood mitigation, increased retention in urban areas, improved urban air quality and microclimate, increased awareness to NBS measures, amenity enhancement and improved governance and citizens’ participation. Additionaly, the green roof is a pleasant space for gathering with friends and leisure. 

Turin Hortus

Aeroponic system for urban farming to be placed on the terrace of the building

Torino topgarden

Torino construction

Torino rooftop paths
Torino flora



Municipality of Turin:
Alessandra Aires, Division of Infrastructure and Mobility, alessandra.aires@comune.torino.it

IRIDRA S.r.l.:
Anacleto Rizzo, rizzo@iridra.com