Climate Resilience in the City's Historic Districts

One of the biggest concerns in all ten of the City's historic districts is managing the effects of climate change - increased heat, precipitation and sea-level rise.

The Office of Historic Preservation, alongside the Office of Climate Resilience under the Environment, Energy, and Open Space Cabinet are leading on addressing climate resilience in historic buildings. This month, the City of Boston will be hosting the second annual Deployables Day, a citywide training exercise on temporary flood protection in recognition of National Preparedness Month

In 2018, in collaboration with the Environment Department, the City issued a Resilient, Historic Buildings Design Guide. This guide was written to help property owners identify the climate risks their buildings may face and what they can do about it. Sea level rise is one of the key climate change effects addressed in the guide. Historic buildings can respond to sea level rise in a variety of ways. One of the most common is dry floodproofing. Dry floodproofing encourages the installation of flood shields and deployable barriers at ground and below grade openings. Brackets are installed (ideally through masonry joints) so that during a major coastal storm event the shields and barriers can be installed, establishing a boundary against rising waters. Though effective, this measure can cause increased pressure on the exterior walls of a building resulting in structural damage. This is thus not a one size fits all solution. An alternative to dry floodproofing is wet floodproofing. Here, spaces below the design flood elevation - the height of the lowest occupiable floor - are designed such that water can flow in and out of the space. Mechanicals and other items in the space should be elevated, moved to different levels of the building (such as on the roof) or designed to function after being submerged in water. This method allows for equal water pressure on both the inside and outside of the building which may help to prevent structural damage.

As the risk of flooding resulting from rising sea levels continues to increase, the City's historic districts are beginning to respond. In November 2024 the Bay Village Historic District Commission updated its standards and criteria, which regulate how properties can be modified in the historic district while maintaining their character. Some of the updates directly addressed the risk of flooding. The installation of temporary, deployable barriers in anticipation of a storm event does not require any review. Properties in the district located in the Sea Level Rise - Flood Hazard Area are able to alter their entryways to manage the effects of flooding. After assessing the possibility of elevating interior floors property owners can work with the Commission to design an elevated entry that is compatible with the style and period of the existing building and the overall character of the historic district.

The Fort Point Channel Landmark District has the highest flood risk of all of the City's historic districts. Here, the implementation of flood

mitigation strategies has begun. All around the district, especially at openings along the first and ground floors of buildings along the Fort Point Channel, you can see the installation of metal brackets used to secure flood shields and deployable barriers during major coastal storm events. At 51 Melcher Street, the building recently underwent a conversion into a life science laboratory. During the conversion, the project team implemented various resiliency strategies such as consolidating utility rooms within the basement and adopting dry floodproofing measures to protect equipment. Additionally, they raised ground-level mechanicals, retrofitted the foundation from the interior at critical points to reduce water infiltration, and installed brackets for deployable flood shields at ground-level openings.

This crucial work in Bay Village and Fort Point Channel is just the beginning. Staff look forward to working with applicants to help mitigate the risks of climate change while working to preserve the City's historic buildings for centuries to come.

• Published by: Historic Preservation