The project followed the principle of multidisciplinary sustainable drainage system (SuDS) design, promoting a SuDS retrofitting intervention capable of providing benefits in terms water quantity, water quality, biodiversity and amenity, and creating a long linear green infrastructures in the urban area. The intervention consists in decreasing the width of the existing road to recover space of including about 1000 m2 of the bioretention systems and a cycle lane. In terms of Water quantity, the SuDS have been designed to retain low intensity rain events, permitting to avoid discharging in combined sewer, on average, 10000 m3/y, draining an impervious surface of about 12000 m2. In terms of Water quality, the porous media of the bioretention systems have been selected to provide an effective treatment of the pullutants in the  stormwater first flush generated by the deposits of pollutant on the roads during dry periods, guaranteeing and effective removal of solids and metals. Regarding Biodiversity, about 1000 m2 of paved surface have been greened back and planted with 14 different shrubs and 7 different trees, contributing also to other benefits typical of urban greening, such as heat island reduction, air pollution control, and noise attenuation. Moreover, the urban greening permitted to achieve also the Amenity benefits; being designed according the SuDS principle, the multipurpose SuDS elements drain in 24-48 hours, permitting to live the area in dry period. To this aim, also a small abandoned square have been recovered, including multipurpose SuDS element together with typical restoration intervention, such as educative games for kids and urban forestation elements.

The opportunity was taken to finance reforestation works for a real redevelopment of the area. From a hydraulic point of view, the de-sealing work contributes to a reduction of water loads on the rainwater collection network; from the point of view of the liveability of urban spaces, it contributes to improving their quality, reducing the heat island effect, controlling the albedo of the external surfaces, intervening with urban greenery to reduce CO2 and consequently, making these spaces usable also in concert with the stakeholders, to encourage initiatives for new social activities and outdoor living.

The project envisages SuDS retrofitting works spread over the entire Market area using the space obtained from the non-concessionary stalls.

There are three elements that distinguish it: the large bioretention area in front of the shopping centre, the linear suds in front of the new shrub and tree belt in the area where the stands were located, and the island suds that cut across the entire market area twice.

The intervention in Via della Repubblica consists mainly of a reorganisation of the road axis by inserting urban drainage systems to relieve the mixed sewage system. The new layout has been realised so that water flows into the bioretention systems directly or through the gutters, the road and pavements have been recalibrated, allowing for large SuDS areas on the east and west side along the road.

For Via della Repubblica, the area of intervention is approximately 1012 square metres and is distributed as follows.

• new driveway
• new pavements on both sides
• 79 square metres of parking area
• 112 sq m of bioretention areas positioned along the road axis, for the drainage of surface water from the driveway, parking areas and pavements.

The "Integrated Urban Plans CMM Spugna" project of the Metropolitan City of Milan, has the objective of relieving the sewage network in various municipalities, to ensure the correct drainage of rainwater, in particular 26 interventions have been designed in 10 municipalities of the Metropolitan City of Milan. The project has chosen to propose unconventional solutions belonging to the families of "Sustainable Urban Drainage Systems" (SuDS) or "Nature-based Solutions" (NBS). Sustainable urban drainage systems are multi-functional systems that allow the management of rainwater on the surface, avoiding overloading the existing sewage network and treatment plants, and reducing local flooding phenomena. Since these are often multi-objective interventions, they are able to provide multiple ecosystem services and contribute to the improvement of the landscape. They also help reduce air, water and heat island pollution, providing support for biodiversity. Specifically, the designers' objective was to exploit the possibility of financing desealing interventions for a real redevelopment of the areas, which would allow, at the same time, to improve the hydrological response of the drained basin and the hydraulic functioning of the existing sewer and to provide benefits to the citizens. The solutions identified for the objectives set are solutions that allow easy insertion in the area of interest and the ability to offer multiple ecosystem services, among the solutions proposed are: rain gardens, detention basins, drainage trenches, permeable pavements, vegetated ditches and infiltrating geocellular modules. The sum of the surfaces of the SuDS elements of all 26 interventions is equal to 31 019 m², for a total of 6314 m³ of lamination volume.

In Besozzo, the de-sealing of the public car park in Via Milano and the redevelopment of the adjoining park was planned, using sustainable urban drainage solutions. Stormwater falling on the surface of the street and car parks in Via Milano is managed by multi-objective SuDS elements such as permeable pavements, dry basins with bioretention areas and wet detention basins. Stormwater falling on the surface of the car parks and the street passes through the filter material layer of the permeable pavement to the dry basin, from where it continues to the wet detention basin. From the basin the water is then discharged into the Bardello River.

Two storage tanks are also positioned in the north-west of the intervention area to collect rainwater from the roof of the ex-Sonnino area building in order to reuse it for the irrigation of the green roof.

The project consists of two interventions in the municipality of Varedo (MB), the de-sealing of Via F. Kennedy, to ensure the drainage of rainwater, and the management through SuDS of rainwater collected from the roofs of the F. Kennedy school.

The project includes the desealing of a longitudinal strip along the Via Kennedy car park and the construction of 154.5 m2 bioretention areas. These de-sealed spaces, located in front of the car parks and near the entrance area to the school, will be able to receive rainwater from Via Kennedy allowing a temporary accumulation of rainwater and subsequent infiltration into the ground, and will also contribute to creating a concrete division between the carriageway and the entrance area to the school.

Specific to the project, water collected from the school roof, which currently drains into the mixed sewer system, will be sent to a rain garden of approximately 157.5 m2 to remove possible pollutants. The filtered water will be collected in a 40 m3 storage tank, so that it will be available both for irrigation and for possible use in the gymnasium (ACS or toilet flushing).

The project involves the redevelopment of Piazza Papa Giovanni XXIII in the municipality of Corsico (MI), with the construction of a car park with permeable paving in the upper part, with bioretention areas in the flower beds between the parking stalls. Runoff from the square is instead conveyed to the storm drains where the new white water sewer will transport it to the detention basin, from where it can infiltrate into the ground through the drainage trench at the bottom.

The Carvico project concerns two de-sealing works to ensure rainwater drainage. In particular, the first intervention concerns the construction of new drains and new sections of white sewer system to drain rainwater from a part of the car park to the area of the new urban park, where a dry detention basin will be built, while for the other part of the car park the drained water will be conveyed to the bioretention area built along the south side of the car park.

The second intervention concerns the disconnection of the drains from the existing sewer system in the area of the forecourt in front of the church and the construction of bioretention areas for the collection and treatment of rainwater from the forecourt. It is also planned to construct infiltrating geocellular modules in the green area at the back of the forecourt.