Mayor Kim Janey today signed a new zoning overlay into effect requiring new development and retrofits to take additional steps to limit the damage and displacement related to the impacts of coastal storms and sea level rise. The Coastal Flood Resilience Zoning Overlay District, goes beyond the areas identified in FEMA flood maps, applying to areas of the City that could be inundated during a major coastal storm event, known as a 1 percent chance flood event with 40-inches of sea level rise. Fulfilling steps outlined in Climate Ready Boston, the Boston Planning & Development Agency (BPDA) Board of Directors approved this new zoning overlay in September. The zoning overlay promotes resilient planning and design, provides consistent standards for the review of projects, and maximizes the benefits of investments in coastal resilience.
“We must take the steps that will better protect our neighborhoods from the increasing threat of coastal storms and sea level rise,” said Mayor Kim Janey. “By requiring developers to do more in vulnerable areas, we are protecting our infrastructure, our jobs, and our homes.”
“For Boston to grow and thrive for generations to come, we must ensure that buildings constructed today are resilient and protected from the impacts of climate change,” said BPDA Director Brian Golden. “By updating our zoning code to go above and beyond the FEMA flood maps, Boston is leading the way in not only preparing for the storms of today, but the storms of tomorrow.”
"In Boston, we know that our most vulnerable communities are disproportionately bearing the burden of the climate crisis," said Reverend Mariama White-Hammond, Chief of Environment, Energy and Open Space. "As a City, we must work together to take the crucial steps to protect all of our residents from the effects of climate change. I am grateful to Mayor Janey and the BPDA for updating zoning measures to enhance our collective resilience."
"Boston Harbor Now has been pleased to be a part of the development of these guidelines, and we appreciate the BPDA’s leadership on this critical topic", said Kathy Abbott, President and CEO of Boston Harbor Now. "As we've learned the hard way over and over again in recent years, Boston sorely needs updated zoning--along with district-wide coastal solutions--to make sure that our most vulnerable citizens and more of our neighborhood buildings are prepared for sea-level rise, storm surges, and other impacts of climate change. We look forward to working with the City to implement these protections."
“The Coastal Flood Resilience Zoning Overlay District is the result not only of hard work to understand the City’s vulnerability to climate change and other hazards but reflects a commitment to employ available tools to address and proactively respond to these imperatives,” said Greg Minott AIA, BSA president and co-founder and managing principal of DREAM Collaborative. “The effects of climate change demand bold and continuous action, and the Boston Society for Architecture applauds the City’s vigilance in seeking to address the risks climate instability pose to Boston’s future.”
Based upon climate modeling, 40-inches of sea level rise is expected around 2070, which is within the usable life of most buildings currently undergoing BPDA review. The 40-inch inundation area is integrated into the BPDA Zoning Viewer.
The Zoning Overlay (Article 25A of the Boston Zoning Code) will provide new definitions and standards for building dimensions and uses to facilitate flood resilient design for new projects and building retrofits. Intended to prevent flood damage by elevating building occupiable space, flood proofing areas beneath flood elevations, and promoting health and safety by preventing uses such as living space below the flood elevation, the specific provisions of the overlay include:
All development projects subject to BPDA’s Article 80 Large and Small Project review will be required to undergo Resilience Review, and comply with the Coastal Flood Resilience Design Guidelines. In 2019, the BPDA adopted Coastal Flood Resilience Design Guidelines to provide clear strategies and best practices for developers, business owners, and residents to respond to climate change. Last year, the American Planning Association (APA) Sustainable Communities Division awarded the BPDA’s Coastal Flood Resilience Design Guidelines with the 2020 APA Excellence in Sustainability Award in the Policy, Law or Tool category.
Building Height: Projects undergoing Resilience Review will have their height measured from two feet above the Sea Level Rise Base Flood Elevation (SLR-BFE), rather than at grade, which is what current zoning requires.
Building Setbacks: Projects will have allowances to extend into side yard, rear yard, and front yard setbacks for structures needed for vertical circulation, such as stairs or ramps to get from surrounding grade to a higher first floor elevation. There are also allowances for side yard and rear yard encroachments for new structures to house mechanical systems to ensure they are not located in basements or beneath the Sea Level Rise Design Flood Elevation (SLR-DFE), which consists of the SLR-BFE plus one to two feet based on type of use.
Lot Coverage and Required Open Space: The structures needed for vertical circulation and mechanical systems referenced above will be excluded from measurement of lot coverage and open space
Gross Square Floor Area: Will exclude structures needed for vertical circulation and areas devoted to flood protection measures.
Limitations on Use Below the Sea Level Rise Design Flood Elevation: For health and safety purposes, uses beneath the SLR DFE are limited to access for vertical circulation structures; flood prevention measures, storage, and parking.
The BPDA released the draft zoning overlay in January and held two public meetings and accepted community feedback. In response to feedback, the draft was updated and posted on August 23.
The BPDA has also launched the Zero Net Carbon Building Zoning Initiative to assess and identify strategies to strengthen green building zoning requirements to a zero net carbon standard for new construction, to meet the City of Boston’s goal for Boston to be carbon neutral by 2050.
Climate Ready Boston assesses Boston's climate projections and vulnerabilities to climate change, and identifies city-wide strategies for reducing vulnerability to sea-level rise, extreme heat, and intense precipitation. Climate Ready Boston is a Citywide initiative to deliver an all-of-government approach across many City and community partners and residents to ensure Boston is resilient to the effects of climate change.