1. General information
2. Objectives of the intervention
Goals of the intervention
The goals of the intervention consisted in analysing the potential impact green roofs have on containing water runoff and reducing the heat island phenomenon highly common in the city of Bologna (2).
- Thermal insulation - The vegetative cover contributes to the reduction of thermal dispersion between indoor and outdoor with a reduction in energy consumption;
- Acoustic insulation;
- Bioclimatic improvement - The green shells, replenishing that lessened biological mass due to the cementation, allow through the photosynthesis the transformation of carbon dioxide into oxygen. In addition, by reducing the emissions caused by the use of air conditioning systems, they contribute to improving environmental viability.
- High water retention - the elements of the package and the substrates are able to return to the environment by evapotranspiration up to 80% of rainwater, thus reducing the flow to the sewage;
- Decrease in the heat island phenomenon - vegetation permits dust retention (7).
- Thermal insulation - The vegetative cover contributes to the reduction of thermal dispersion between indoor and outdoor with a reduction in energy consumption;
- Acoustic insulation;
- Bioclimatic improvement - The green shells, replenishing that lessened biological mass due to the cementation, allow through the photosynthesis the transformation of carbon dioxide into oxygen. In addition, by reducing the emissions caused by the use of air conditioning systems, they contribute to improving environmental viability.
- High water retention - the elements of the package and the substrates are able to return to the environment by evapotranspiration up to 80% of rainwater, thus reducing the flow to the sewage;
- Decrease in the heat island phenomenon - vegetation permits dust retention (7).
Quantitative targets
retention of up to 80% of rainwater
covering up to 1000 sqm with vegetation (7)
covering up to 1000 sqm with vegetation (7)
Monitoring indicators defined
In this paper the following factors affecting runoff dynamics from green roofs were considered: type of green roof and its geometrical properties; soil depth and moisture characteristics; season, weather and rainfall characteristics; vegetation. All these aspects were controlled and monitored thorough the design and construction process and then through specific environmental sensors which were installed on the prototyped extensive green roof located in Bologna, on the roof of the DICAM Department laboratory (1).
Sustainability challenge(s) addressed
Climate change adaptation: What were the goals of the NBS?
Climate change adaptation: What activities are implemented to realize the conservation goals and targets?
Climate change mitigation: What were the goals of the NBS?
Climate change mitigation: What activities are implemented to realize the conservation goals and targets?
Implementation activities
At the end of the planning process, it took few months for the roof to be installed. The first months required more careful maintenance since it was over summer. Plants needed to be watered more frequently. Constant observation of the roof were carried both viasually and through specific sensors. The approach was keeping half of the roof of the university building as the conventional concrete roof and the other half as green roof, in order to make a comparison of their performances in terms of water retention and heat mitigation (1).
Type of NBS project
3. NBS domains, ES and scale
4. Governance and financing
5. Innovation
Type of innovation
Please specify technological innovation
It is the first green roof in the city of Bologna with the aim to reduce water runoff (1).
Novelty level of the innovation
Please specify novelty level of the innovation
There is another case in Genova, but since the coastal climate is very different from the Region Emilia-Romagna in the inland, this project had to take a different approach and use different kinds of plants (1).
Replicability/Transferability
Please specify Replicability/Transferability
After the successful observation of the impact of the green roof on the DICAM roof, the agrarian and veterinary faculties followed the example by building green roofs in 2014, for a total area of over 1.000 sqm (4).
