Sustainable drainage systems (SuDS)
Sustainable drainage systems (SuDS) want to manage urban runoff in order to: (i) restore hydrological balance and reduce pollutant loads of water bodies, moving from a post-urbanization back towards a pre-urbanization status of water bodies; (ii) build the so-called Sponge Cities, i.e. cities able to soak the urban runoff and mitigate flood effects; (iii) build green-blue infrastructure able to exploit all the Ecosystem Services of Nature-Based Solutions.
IRIDRA proposes SuDS solutions for sustainable management of rainwater, trying to conjugate the environmental needs with the possibility to restore neglected urban areas.
The drainage of urban runoff was usually underestimated in the planning and design of current cities. It resulted in serious hydraulic risks once the cities increased too much the cover with impervious surfaces, leading to often urban flood events due to functioning in pressure of sewers. But the current approach leads also to many issues in terms of water quality, due to pollutant load conveyed to water bodies by first flushes and combined sewer overflows.
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Sustainable drainage systems - the concept
Sustainable Drainage Systems (SuDS) want to manage urban runoff to:
- recover the original hydrologic regime and reduce the pollutant loads, moving from post-development back again to pre-development status;
- build future sponge cities in response to heavy rains;
- provide cities with as much as possible new green-blue infrastructures, exploiting the multiple ecosystem services of nature-based solutions
Source: Woods Ballard et al. 2015. "The SuDS Manual"
SuDS and Ecosystem services
Ecosystem services are defined as the "direct or indirect contribution of an ecosystem to human wellbeing".
SuDS techniques provide a number of different ecosystem services additional to that of runoff drainage. For instance, 17 examples of ecosystem services given by SuDS - Soft Engineering - instead of conventional solutions - Hard Engineering - are reported (Huber, 2010):
- atmospheric regulation
- climate regulation
- disturbance regulation
- water regulation
- water supply
- erosion control and sediment retention
- soil formation
- nutrient cycling
- waste treatment
- pollination
- species control
- refugia/habitat
- food production
- genetic resources
- recreation
- cultural enrichment
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
SuDS and Green-Blue Infrastructures
Green-Blue Infrastructure is defined as a network of green and blue spaces exploiting ecosystem services to provide benefit for people and the environment.
Urban park following a SuDS approach in Singapore (Bishan). Source: Gibelli G., 2015, Manuale di drenaggio urbano (in Italian)
SuDS and Sponge Cities
Sponge city is a concept developed in China, in which the city is required to adsorb urban runoff as "sponges" in order to reduce the flood risks driven by increased urbanization. In this clear how a SuDS approach is suitable to develope Sponge cities.
SuDS, WSUD, LID, BMPs ...
The SuDS approach is known in literature with different keywords, developed by research groups of different states. The most known ones are the following:
- SuDS Sustainable Drainage Systems
- WSUD Water Sensitive Urban Design
- LID Low Impact Development
- BMP Best Management Practices
SuDS experiences - International
Atelier Dreiseitl, Potdamer Plaza, Berlino (Germania)
Tanner Springs Park, Portland (USA)
Water Plaza, Rotterdam (Olanda). Fonte: Gibelli G., 2015, Manuale di drenaggio urbano
Sydney (Australia). Fonte: Gibelli G., 2015, Manuale di drenaggio urbano
SuDS experiences - IRIDRA
Open water tanks for climatic regulation with harvested rainwater, Kerakoll research centre (Sassuolo, MO - Italy), designed by IRIDRA in collaboration with BIOS-IS S.r.l.
Bioretention system for sustainable drainage of rainwater, Kerakoll research centre (Sassuolo, MO - Italy), designed by IRIDRA in collaboration with BIOS-IS S.r.l.
Constructed wetland for the treatment of combined sewer overflow of Gorla Maggiore (VA - Italy). The wetland was designed a multipurpose, exploiting different ecosystem services in the new "Water Park" of Gorla Maggiore: water quality improvement of Olona river, flood mitigation, public recreational area, and biodiversity increase. The "Water Park" of Gorla Maggiore was one of the case studies of the EU OpenNESS project.
Urban wetland included in the intervention for the Santa Chiara Open Lab project, financed by Italian fund for suburbs restoration ("Bando Periferie"). The wetland receives the runoff from roofs and is designed as a multi -purpose intervention: treatment and reuse (gardening) of rainwater; flood mitigation; biodiversity increase in the urban environment; aesthetic.
The Eco-Boulevard and the Water Arena for the Lazzareto quartier of Bologna. IRIDRA's proposals for the Climate Change Adaptation of the Bologna Municipality, included in the technical assistance given to Atkins in the study "Climate Change Adaptation and Resilient Cities" (financed by the European Investment Bank -EIB). These proposal were included in the new guidelines of Bologna Municipality for SuDS systems, one of the action of the Bologna Climate Change Adaptation Plan developed under the BlueAP LIFE project.
SuDS implementation scales
The different sustainable drainage systems (SuDS) allow to propose a SuDS approach to different implementation scales, which can be subdivided as follow:
- building
- property lots
- street and parking
- open spaces
- Retrofitting of existing green areas
IRIDRA proposes the SuDS approach for all the scales, from single houses to public open spaces, up to big peri-urban areas.
Single house scale
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Lot scale
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Parking
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Roads
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areass
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Urban planning and public spaces
 |  |
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Source: Huber, J., 2010. Low Impact Development: a Design Manual for Urban Areas
Retrofitting of existing green areas
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Techniques of Sustainable drainage systems (SuDS)
Techniques of Sustainable drainage systems (SuDS) are various and allow reaching different multidisciplinary goals: flood protection, water quality improvement, urban restoration or biodiversity increase. In function of which goal wants to be maximized, it is possible to use simple trench filters, going through vegetated swales, up to bioretention systems, ponds, and wetlands.
IRIDRA has all the multidisciplinary expertise to propose different SuDS techniques, in function of different required goals.
Rain water harvesting
 |  |
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Green roofs
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Infiltration basins
Fonte: Woods Ballard et al. 2015. "The SuDS Manual"
Swales
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Bioretention systems
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Infiltration trees
 |  |
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Detention basins
Source: Woods Ballard et al. 2015. "The SuDS Manual"
Ponds
Source: Gibelli G., 2015, Manuale di drenaggio urbano
Wetlands
Source: Gibelli G., 2015, Manuale di drenaggio urbano
Courtesy: Jaime Nivala
IRIDRA's projects
Kerakoll research centre, Sassuolo (MO - Italy)
Chosen SuDS solution: Open-water tanks
Peculiarity: Rainwater harvesting and landscaping
Year of realization: 2012
Kerakoll research centre, Sassuolo (MO - Italy)
Chosen SuDS solution: Bioretention system
Peculiarity: Nature-based solution sited in the proximity of a building of high aesthetic value
Year of realization: 2012
The Eco-Boulevard and the Water Arena for the Lazzaretto quartier, Bologna (BO - Italy)
Chosen SuDS solution: Swales, bioretention systems, urban detention basin
Peculiarity: IRIDRA's proposal for the Climate Change Adaptation of the Bologna Municipality, included in the technical assistance given to Atkins in the study "Climate Change Adaptation and Resilient Cities" (financed by the European Investment Bank -EIB). These proposal were included in the new guidelines of Bologna Municipality for SuDS systems, one of the action of the Bologna Climate Change Adaptation Plan developed under the BlueAP LIFE project
Year of the study: 2017
Sustainable drainage systems in Sesto Ulteriano (Metropolitan City of Milan - Italy)
Chosen SuDS solution: Bioretention systems, urban detention basins
Peculiarity: IRIDRA SRL design proposals in the feasibility study jointed with Majone and Partners Engineering Studio Gioia Gibelli, and Studio Idrotecnico for SuDS retrofitting of an industrial and urban catchment in Sesto Ulteriano, including retrofitting intervents along roads, parking lots and industrial sites. A study financed by PoliS Lombardia.
Year of the study: 2018
Retrofitting SuDS of BEN-ESSERE quartier, Bresso (Metropolitan City of Milan - Italy )
Chosen SuDS solution: Bioretention systems, wet swales, dry detention basins in urban park area
Peculiarity: Within the framework of urban desealing interventions with SuDS, it was taken the chance to design multipurpose elements able to also provide urban restoration of the BEN-ESSERE (wellness) quartier of Bresso. The design followed a "Water Sensitive" approach, infiltrating road runoff, and conveying road runoff overflow and roof runoff by a swale towards a detention basin within the urban park "Parco Nord", where volume control strategy according to local legislation (Reg. RL 07/2017) is provided.
Year of design: Preliminary design, 2021
Retrofitting SuDS Matteotti boulevard, Bovisio Masciago (MB - Italy)
Chosen SuDS solution: Bioretention systems, urban detention basins
Peculiarity: Within the framework of urban desealing interventions with SuDS, it was taken the chance to design multipurpose elements able to also provide urban restoration.
Year of design: Preliminary design, 2021; Detailed design ongoing
Retrofitting SuDS area Mercato presso via Paganini, Bovisio Masciago (MB)
Chosen SuDS solution: Bioretention systems with trees, urban detention basins
Peculiarity: Within the framework of urban desealing interventions with SuDS, it was taken the chance to design multipurpose elements able to also provide urban restoration of the market area, currently fully impermeable and without green spaces .
Year of design: Preliminary design, 2021; Detailed design ongoing
Nature-based solutions for urban flood mitigation in the San Paolo quartier, Prato (PO - Italy)
Chosen SuDS solution: Bioretention systems, dry detention basins , constructed wetlands for CSO
Peculiarity: Feasibility study for the study of potential NBS to reduce pluvial flooding of San Paolo quartier. Both "before-pipe" and "end-of-pipe" NBS solutions have been investigated, proposing different implementation scenario coupled with typological examples of the proposed NBS
Year of the study: 2021
Villese-Gorizie highway, Veneto Region (Italy)
Chosen SuDS solution: Off-line treatment: First flush tank + HF + FWS + Detention and infiltration basin
On-line: HF/VF
Peculiarity: Multipurpose nature-based solution: environmental impact mitigation, landscaping improvement of highway. Designed by IRIDRA for Autovie Venete
Year of realization: 2015
Combined sewer overflow of Gorla Maggiore (VA - Italy): The "Water Park"
Yearly treated volumes of first flush: 150.000 m3/year
Chosen SuDS solution: VF + FWS
Peculiarity: Multipurpose nature-based solution integrating different ecosystem services within the new "Water Park" of Gorla Maggiore: water quality improvement of Olona river, flood mitigation, recreational site, and biodiversity increase. Case study of EU funded project OpenNESS.
Year of realization: 2012
Park of Santa Domenica Valley in Ragusa (RG - Italy)
Chosen SuDS solution: Circular aerated wetland
Peculiarity: Nature-based solution included in the intervention of the urban restoration of the urban park of Santa Domenica Valley, in the Ragusa historical centre
Year of realization: 2018
Santa Chiara Open Lab in Trento (TN - Italy)
Chosen SuDS solution: Urban wetland
Peculiarity: Nature-based solution included in the intervention for the Santa Chiara Open Lab project, financed by Italian fund for suburbs restoration ("Bando Periferie"). The wetland receives the runoff from roofs and is designed as a multipurpuse intervention: treatment and reuse (gardening) of rainwater; flood mitigation; biodiversity increase in urban environment; aesthetic.
Year of design: 2018
Kerakoll research centre, Sassuolo (MO - Italy)
Chosen SuDS solution: Rain garden
Peculiarity: Nature-based solution sited in proximity of a building of high aestethic value
Year of realization: 2012
Residential area in Preganziol (TV - Italy)
Chosen SuDS solution: Rain Garden
Year of realization : 2009
Restoration of Roggia Borromeo in Sant'Isidoro, Carugo (CO - Italy)
Chosen SuDS solution: Dry swale, Dry detention basin
Peculiarity: Multipurpose nature-based solution integrating different ecosystem services: water quality improvement, flood mitigation, recreational site, and biodiversity increase.
Year of design: 2016
