Boston Harbor Association Releases Sea-level Rise Report, Mayor Responds with Policy Initiatives

February 6, 2013

In a new report, Preparing for the Rising Tide, the Boston Harbor Association finds that before 2100, nearly six percent of the city will be flooded twice daily at high tide. The report’s figures are based on an anticipated five feet of sea-level rise by 2100. 

The severe flooding is also a problem in the here and now, report authors say. If Sandy’s storm surge had hit Boston five and a half hours earlier at high tide, the city would have experienced a 100-year coastal flood, which also could have left about six percent of the city submerged under water.  As the seas continue to rise, so will the flooding problems created by storm surge.  A similar 100-year storm surge on top of 2.5 feet of sea-level rise, for example, would flood more than 30 percent the city, the report finds.

This map, released in the new report Preparing for the Rising Tide, shows flood depths up to 7.5 feet in Boston, a scenario that represents what a 100-year storm surge might look like in the city in 2050.

The report includes case studies offering vulnerability assessment and preparedness plans for two waterfront sites in Boston.  The report also presents a number of recommendations, with cost estimates, for adapting specific sites, structures and assets including, dry flooding proofing, changing access routes, and elevating critical building infrastructure.

Citing the report, Boston Mayor Tom Menino unveiled a series of planning and policy initiatives to better prepare for climate change impacts. In addition to calling on his cabinet members to accelerate implementation of the city's Climate Action Plan, Menino said he will convene several panels to review existing policies and recommend how institutions and businesses can reduce their vulnerability and how the city can support those efforts. The Mayor said he is directing the Boston Redevelopment Authority to survey the preparedness of all city buildings and other assets, such as the subway, likely to face climate change-related vulnerabilities. He is also calling on the Boston Conservation Commission to draft a wetlands ordinance that incorporates best practices for protection against sea-level rise and storm surge, as well as new floodplain maps that incorporate projected changes. 

In addition to the Mayor’s effort, the city plans to require the review of a project’s climate change preparedness as part of the city’s development review guidelines, and to develop guidelines for better enforcement of the city’s flood-proofing requirements for existing buildings.