Last updated: August 2022
The Porous Alley consists of a strip of porous asphalt in a public alley aimed at filtering stormwater and managing runoff in the affluent South End neighbourhood of Boston. Most of the neighbourhood around the NBS location is filled with land that once was tidal marshes, supported by wood pilings, and threatened by falling groundwater levels. The Porous Alley was designed and implemented as a demonstration project to test the feasibility of using porous asphalt to increase groundwater recharge and reduce flooding and water pollution. The increasing groundwater level has high importance in the area the NBS is located in as building foundations are at risk from low water levels. (1,2)
Source: https://www.crwa.org/hubfs/Our_Work/Blue_Cities_Initiative/Green_Infrastructure_Projects/Porous_Alley/porous-alley-demonstration-project.pdf
Overview
Nature-based solution
- Green areas for water management
- Sustainable urban drainage systems
Key challenges
- Climate action for adaptation, resilience and mitigation (SDG 13)
- Climate change adaptation
- Water management (SDG 6)
- Stormwater and rainfall management and storage
- Improvements to water quality
Focus
Knowledge creation and awareness raising, Other
Project objectives
- Testing the efficacy of new green technology in Boston – porous asphalt in streets and alleyways
- Recharging groundwater levels to reinforce the structural integrity of nearby buildings
- Cleaning and filtering polluted runoff to prevent it from entering the Charles River (1)
Implementation activities
- Selection of an ideal area for the demonstration project based on several criteria
- Pre-construction on-site soil test (2)
- Coordination of several public meetings to ensure that area residents were comfortable with and well informed about the project
- Creation of a storage area beneath the porous asphalt layer from coarse gravel with a capacity of 425 cubic feet (approximately 12 m3) of water storage (2)
- Installation of an overflow pipe from the storage area into the existing sewer to prevent any possible overflow from the storage area. (2)
- Installation of a 6-inch diameter well to the storage area with an access cap at the surface to monitor infiltration (2)
Climate-focused activities
Climate change adaptation:
- Implement sustainable urban drainage infrastructure (e.g. to make space for water)
Main beneficiaries
- Citizens or community groups
Governance
Management set-up
- Co-governance with government and non-government actors
Type of initiating organisation
- Local government/municipality
- Non-government organisation/civil society
- District/neighbourhood association
Participatory approaches/ community involvement
- Dissemination of information and education
- Consultation (e.g. workshop, surveys, community meetings, town halls)
Details on the roles of the organisations involved in the project
The initiative of a demonstration project of porous asphalt arose from the partnership among the City of Boston Public Works Department, the Charles River Watershed Association (CRWA), and the Boston Groundwater Trust (BGWT) in 2013 (1,2)
Project implemented in response to ...
... an EU policy or strategy?
No
... a national policy or strategy?
No
... a local policy or strategy?
Yes
(The City of Boston has adopted a Groundwater Conservation Overlay District (GCOD), Article 32 zoning, in sections of the City to protect wood pile foundations of buildings from being damaged by lowered groundwater levels. The Porous Alley Demonstration project testing porous asphalt as green infrastructure technology to abide by 2012 consent decree requiring Boston Water and Sewer Commission to implement better water pollution control mechanisms (1))
Financing
Total cost
€50,000 - €100,000
Source(s) of funding
- Public national budget
Type of funding
- Earmarked public budget
Non-financial contribution
Unknown
Impacts and Monitoring
Environmental impacts
- Water management and blue areas
- Improved water quality
- Improved stormwater management
- Enhanced protection and restoration of freshwater ecosystems
Economic impacts
- Unknown
Socio-cultural impacts
- Unknown
Type of reported impacts
Achieved impacts
Presence of formal monitoring system
Yes
Presence of indicators used in reporting
Yes
Presence of monitoring/ evaluation reports
Yes
Availability of a web-based monitoring tool
No evidence in public records
References
"1) Kim, E., 2018, NATURVATION - Case Study Working Paper: Boston, Massachusetts, USA
2) City of Source link. Boston’s Porous Alley Demonstration Project Summary Report. Accessed on 16 February 2021. Source link
3) Boston Public Works Department - The Mayors Office of Neighborhood Services. (2013). Boston Porous Alley Project - Public Meeting. Accessed on 16 February, 2021. Source link
2) City of Source link. Boston’s Porous Alley Demonstration Project Summary Report. Accessed on 16 February 2021. Source link
3) Boston Public Works Department - The Mayors Office of Neighborhood Services. (2013). Boston Porous Alley Project - Public Meeting. Accessed on 16 February, 2021. Source link
Source: https://www.crwa.org/hubfs/Our_Work/Blue_Cities_Initiative/Green_Infrastructure_Projects/Porous_Alley/porous-alley-demonstration-project.pdf