Dive Brief:
- Boston announced last week that it has completed the nation’s largest single installation of green roofs on bus shelters.
- As part of a three-year demonstration project, the city put green roofs on 30 bus shelters to capture more stormwater, increase biodiversity, provide shade and improve air quality.
- The initial installations are along the most popular bus route run by the Massachusetts Bay Transportation Authority, but Boston is interested in scaling the strategy to other areas in the city.
Dive Insight:
As cities grapple with record-breaking heat waves and intense storms driven by climate change, green roofs present a small part of the potential solution. These vegetative layers planted on rooftops can reduce the temperature of a roof by 30 to 40 degrees Fahrenheit compared with conventional structures, according to the U.S. Environmental Protection Agency. Buildings with green roofs are also more energy efficient, the EPA says. However, green roofs can also be costlier to install than conventional roofs, and the plantings may require maintenance.
A few cities mandate developers to include green roofs in certain cases, while others simply incentivize them. Boston first piloted retrofitting bus shelters with green roofs in 2014 through a project that affected three bus shelters. The city’s recent, larger deployment of green roofs “is a tangible example of how we can reimagine our urban infrastructure to be more resilient, sustainable, and equitable,” Boston Chief Climate Officer Brian Swett said in a statement.
Since the city’s bus shelters typically have transparent roofs, covering them with greenery will improve access to shade while creating habitat for birds and pollinators. The plantings will also absorb stormwater and reduce runoff, helping to prevent flooding, according to a news release. That will help reduce stress on the city’s “aging and often undersized drainage systems” that “struggle to handle intense rainfall, leading to inundated streets and property damage,” the city says on a webpage about the green roofs.
Boston will collect and analyze data on the impact of green roofs with the help of local architecture and design firm Social Impact Collective. They will look at how much stormwater the roofs retain, the temperature difference between the green roofs and the sidewalk and how much the plants on the roofs grow.