What is the (G)BRAG Report?
On June 1, 2022, the Greater Boston Research Advisory Group (GBRAG) published its report, Climate Change Impacts and Projections for the Greater Boston Area. The report, which looks at the impacts of climate change on the 101 cities and towns that make up the Metropolitan Area Planning Council’s region, provides updated projections for inland flooding and extreme precipitation, extreme heat, and sea level rise and coastal flooding.
The report is a follow-up to a 2016 report of the Boston Research Advisory Group (BRAG), which was the first effort to provide more specific projections of the impacts of climate change on Boston through the year 2100. The 2016 report became a planning document for the City and formed the basis for Climate Ready Boston, an ongoing neighborhood-by-neighborhood initiative to prepare Boston for the future impacts of climate change.
The report gained significant traction outside of Boston, for good reason, and is used regularly by several other cities and agencies to develop regulations and policies, vulnerability assessments, and local resilience and adaptation plans. The June 2022 GBRAG Report is significant for two reasons: it updates the 2016 projections and provides a wider lens of the impacts of climate change on the entire Greater Boston region.
Updated Climate Change Projections
The GBRAG Report predicts more extreme precipitation events will result from climate change, leading to more inland flooding from rivers and stormwater overflow. Existing and ongoing greenhouse gas emissions will continue to contribute to more extreme heat events. The GBRAG Report predicts that there will be more than 20 days of 90-degree heat each year by 2040, more than 31 such days by 2080, and more than 33 by 2100, under an intermediate emissions scenario. Under the high emissions scenario, the Greater Boston region could experience more than 62 days of 90-degree heat per year by 2100.
One of the more significant updates, which could have immediate planning and land-use permitting implications, is the GBRAG Report’s updates to coastal flooding projections caused by a combination of increasing sea level rise and storm surges. Through 2050, the GBRAG Report now projects flood heights to be 2 to 16 centimeters (.788 inches to 6.304 inches) higher than the 2016 projections under the intermediate emissions scenario and 5 to 26 centimeters (1.97 to 10.244 inches) higher under the high emissions scenario.
What does this mean for local permitting?
The GBRAG Report and the updated coastal flooding projections could bring changes to permitting requirements for developers pursuing projects in Boston. If you are a project proponent or consultant, here are a couple of areas to watch out for:
Boston Zoning Code’s Coastal Flood Resilience Overlay District, Article 25A
In Fall 2021, the Boston Zoning Code was amended to add Article 25A and create the Coastal Flood Resilience Overlay District (CFROD). The boundaries of the CFROD are based on the extent of flooding for the 1% annual chance coastal flood event in 2070, factoring in 40 inches of sea-level rise.
Article 25A generally applies to projects that (1) increase gross floor area by at least 20,000 square feet, (2) add 15 or more dwelling units, (3) result in a substantial rehabilitation of, or resulting in, at least 100,000 square feet of gross floor area, or (4) establish or change a use of 50,000 square feet outside Downtown or 100,000 square feet in Downtown.
Projects subject to Article 25A are required to include 1-2 feet of freeboard above the base flood elevation in 2070, accounting for projected sea level rise, and undergo resilience review similar to that under Article 80’s small and large project review. Under resilience review, a developer must demonstrate to the Boston Planning & Development Agency that the project incorporates best practices and standards to reduce or eliminate coastal flood risk or damage from future climate conditions, relying on the most recent flood hazard modeling and mapping data.
The GBRAG Report could mean two things for developers when they consider Article 25A compliance. First, the increased coastal flooding projections could affect the boundary of the CFROD and expand the number of private property owners subject to Article 25A’s minimum design flood elevation requirements and resilience review. Article 25A allows the Building Commissioner to adjust the boundary and determine that a site is within or outside the CFROD if information on sea level rise or storm surge does not reflect actual site conditions. The Building Commissioner’s decision to include or exclude a property from the CFROD is appealable to the Zoning Board of Appeal. Second, the increased coastal flooding projections could mean that projects within the CFROD may be subject to heightened design flood elevation requirements of 1-2 feet of freeboard above the updated projections.
Boston Wetlands Protection Ordinance
In 2019, the Boston City Council enacted an Ordinance Protecting Local Wetlands and Promoting Climate Change Adaptation in the City of Boston. The Ordinance prohibits work or activities in defined wetland resource areas without first filing a permit application, called a Notice of Intent, with the Boston Conservation Commission. The Ordinance creates a resource area called the Coastal Flood Resilience Zone (CFRZ), which is defined as the area beyond the existing floodplain which the Commission determines has a reasonable probability of becoming subject to coastal storm flooding due to sea level rise within the next 50 years. As with the CFROD, the increased coastal flooding projections could affect the boundary of the CFRZ and expand the number of private property owners subject to local wetlands permitting.
Regardless of whether your project falls within the CFRZ, property owners and developers subject to local wetlands permitting need to be familiar with the GBRAG Report because the Ordinance requires every project proponent to integrate climate change and adaptation planning considerations into the project. These considerations include the impacts of sea level rise and changes in coastal flooding.