St. Petersburg City Council member Brandi Gabbard believes that innovation can help reduce localized flooding and building energy use.
The Council unanimously approved a new business item July 9 to further explore blue-green roofs by considering density bonuses for developers that incorporate the technology into new multifamily residential developments.
A density bonus allows developers to build more housing units on a property than zoning would otherwise permit.
Gabbard submitted the request.
According to a City document, a blue-green roof is “a specialized building system that integrates a living vegetation layer with an underlying water-retention void to transform standard rooftops into functional infrastructure.”
This can also reduce the urban heat island effect. According to the National Aeronautics and Space Administration (NASA), the phenomenon occurs “when a city experiences much warmer temperatures than nearby rural areas.”
Gabbard explained to the Catalyst that the system can not only help manage stormwater runoff, but also can increase green space in the community.
“I think that we’re missing a bit of an opportunity with all of these roofs that are going up across our city,” she said. “This, I think, is a creative way for us to look at being able to utilize that additional space.”
A trip to San Francisco inspired Gabbard to investigate blue-green roofs. That city’s Salesforce Transit Center, which opened in 2018, has a 5.4-acre park on the top of its roof.
According to the Transbay Joint Powers Authority, which owns and operates the site, the community asset stretches nearly four blocks in length. It features 600 trees, 16,000 plants and 13 botanical areas.
“All of us need to just really make sure that we are keeping in mind as we continue to redevelop our city that we are built out,” Gabbard added. “We’re really going to have to work with what we have.”
“I want us to be very thoughtful in the ways that we allow new development,” she continued. “If there is any opportunity for us to utilize new technologies, rooftop gardens or green spaces, that really, from an environmental standpoint, is part of my charge at City Council.”
With the approval, the item will either be presented to the Health, Energy, Resilience and Sustainability Committee or the Housing, Land Use and Transportation Committee. Ideally, Gabbard hopes to further discuss the idea in the fall depending on scheduling.
She added that it is too early to determine the specifics of any potential density bonus.
“I very much look forward to having those conservations with my colleagues and seeing what the temperature is for being able to make this change,” she said. “I would tell everybody who is interested in it to stay tuned, and if they have any sort of ideas about what that might look like, to definitely reach out to City Council.”