Mayor Michelle Wu announced a new policy to require that certain City projects include environmental benefits and stormwater mitigation through the use of green infrastructure. The policy establishes five new standard designs and the necessary accompanying maintenance resources to expand the implementation of small-scale green infrastructure installations in Boston. In dense urban areas where space in public sidewalks and roadways (referred to as the right-of-way) is limited, small-scale green infrastructure (GI) can be effective in reducing stormwater flooding, promoting groundwater recharge, and filtering pollutants from runoff. Additionally, green infrastructure has numerous co-benefits, including increasing urban tree canopy, mitigating urban heat island effect, and enhancing ecological diversity.
“Today we are announcing Boston’s first ever green infrastructure policy and in doing so setting a new standard for safer, more sustainable roadway infrastructure throughout the city,” said Mayor Michelle Wu. “Together these elements will improve community safety, foster community engagement, and boost our climate resilience.”
This new policy will apply to curb extensions, also known as neckdowns, bulb-outs, or bumpouts. Curb extensions improve safety at crosswalks by reducing the distance to cross from one side of the street to the other and preventing vehicles from parking too close to crosswalks, making pedestrians more visible to drivers. Curb extensions can also be used to ensure that crosswalks are accessible for people with limited mobility or in wheelchairs. Due to Boston’s compact nature, curb extension projects often result in the creation of small spaces not suited for other uses. Historically, these spaces have been paved with impervious materials.
“These new design standards will allow the City to continue enhancing our streets as public spaces for everyone,” said Chief of Streets Jascha Franklin-Hodge. “These curb extensions help keep our neighborhood safe by slowing cars and making street crossing easier for pedestrians and now they can also benefit our quality of life by providing more green space in our City.”
“Integrating green infrastructure into the City’s projects as a standard will help us reduce stormwater flooding, create new green space and provide more shade in all of our neighborhoods,” said Kate England, Director of Green Infrastructure. “We are also excited to introduce a volunteer program that will foster stewardship by creating opportunities for neighbors to come together and take care of these new features.”
“Innovative green infrastructure policies offer an additional pathway to adapt to the impacts of climate change, such as stormwater flooding and sea level rise, while making our communities more resilient,” said Reverend Mariama White-Hammond, Chief of Environment, Energy and Open Space. “I am excited to support these new design measures that will bring us closer to our collective goal of being a Green New Deal city.”
The purpose of this policy is to aid the City in implementing preferred GI alternatives to current design practices and ensure adequate maintenance so that GI can be integrated as standard practice into large-scale capital projects in the future. The five design alternatives are as follows:
1 Right-of-way (ROW) Bioretention: Curb extensions may incorporate green infrastructure in the form of Rain Gardens, Bioswales, etc.
2 Infiltration Tree Pit/Tree Trench: Curb extensions may incorporate green infrastructure in the form of Infiltration Tree Pits or Infiltration Tree Trenches.
3 Porous Paving: Curb extensions may incorporate Porous Asphalt, Permeable Pavers, Porous Paver Installations, and Porous Concrete Slabs.
4 Subsurface Infiltration Area: Curb extensions may incorporate Stone Subsurface Infiltration Areas (with or without perforated pipe).
5 One-time Seeding: The area within the curb extension may be seeded once with a groundcover, low-grow fescue or wildflower mix.
Additionally, to help support the longevity of green infrastructure, two GI-specific maintenance contracts will be available for maintenance on new and existing public GI installations. The first is a contract for maintenance on porous paving installations. The second is a contract for landscape maintenance on “green” infrastructure features. These two contracts will provide much needed regular maintenance, including regenerative air vacuum sweeping for porous paving, as well as vegetation maintenance, replacement, and pruning for GI features in the right-of-way. They will also provide the flexibility required to perform maintenance as needed or requested by residents through the City’s 311 system.
The policy will also establish a volunteer program to assist in the maintenance of select GI sites. Prospective volunteers will be able to sign up through an online portal to “adopt” a GI feature. This program will allow volunteers to aid in litter removal and/or seasonal cleanups for GI features where they live, work, and play.
This infrastructure will complement the City’s network of nearly 36,000 catch basins connected to roughly 600 miles of pipes beneath our streets, which is maintained by the Boston Water & Sewer Commission.
Today’s announcement builds on the Wu administration’s commitment to creating resilient communities while adapting to the impacts of climate change. Green infrastructure is a key component of the recently released Urban Forest Plan, which includes strategies to bolster the City of Boston’s tree canopy while enhancing the livability and public health of Boston’s neighborhoods. Curb extensions will be a common tool in implementing the Mayor’s vision for safer streets, announced in September.