Boston Mayor Michelle Wu has announced a new policy mandating the use of small-scale green infrastructure on curb extension projects throughout the city.

A set of five design standards will be introduced to help expand the adaptation and maintenance of the measures with the larger aim of improving pedestrian safety and bolstering climate resilience of the city’s crowded walkways and streetscapes.

“These new design standards will allow the City to continue enhancing our streets as public spaces for everyone,” Boston’s Chief of Streets, Jascha Franklin-Hodge, said in a statement. “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.”

Boston planners say the policy will eventually lead to the implementation of green infrastructure into large-scale capital projects, combining with its recently-proposed ban on fossil fuels in new construction in order to enable what another official called the “collective goal of being a Green New Deal city.”

 According to the city's press release, the five new standards are:

• Right-of-way (ROW) Bioretention: Curb extensions may incorporate green infrastructure in the form of Rain Gardens, Bioswales, etc.
• Infiltration Tree Pit/Tree Trench: Curb extensions may incorporate green infrastructure in the form of Infiltration Tree Pits or Infiltration Tree Trenches.
• Porous Paving: Curb extensions may incorporate Porous Asphalt, Permeable Pavers, Porous Paver Installations, and Porous Concrete Slabs.
• Subsurface Infiltration Area: Curb extensions may incorporate Stone Subsurface Infiltration Areas (with or without perforated pipe). 
• One-time Seeding: The area within the curb extension may be seeded once with a groundcover, low-grow fescue or wildflower mix. 

In addition to the design standards, two new maintenance contracts will help ensure the infrastructure will be operated at maximum efficiency. Boston is just one of more than 700 cities facing federal requirements to invest in stormwater management systems that prevent the pollution of important waterways. The press announcement mentioned the infrastructure’s ability to complement the city’s existing network of gray infrastructure, which is managed by the Boston Water & Sewer Commission.