Posted on September 18, 2026
Boston could be facing tens of billions of dollars in flood damage unless it undertakes one of the largest climate adaptation efforts ever proposed for a U.S. city.
That’s the bottom line in a draft feasibility study dubbed the Coastal Storm Risk Management Feasibility Study, which was released recently by the U.S. Army Corps of Engineers (USACE).
The study outlines a sweeping, multi-decade coastal protection strategy that could cost between $9 and $10.5 billion. The plan calls for more than 20 infrastructure projects to be built along 16 miles of Boston’s 47-mile coastline, including floodwalls, levees, berms and floodgates designed to shield the city from rising sea levels and increasingly severe coastal storms.
The study paints an urgent picture of the risks facing Boston. More than 40 per cent of residents already live in areas vulnerable to coastal flooding, and without additional protections, floodwaters could threaten critical transportation networks, hospitals, businesses and neighbourhoods far beyond the waterfront.
The proposed infrastructure and improvements would protect against an estimated $41 billion in future damages, underscoring what city and federal officials describe as a once-in-a-generation investment in Boston’s future.
In a statement, Boston Mayor Michelle Wu said: “With more frequent flooding in vulnerable areas during extreme weather events, the Coastal Storm Risk Management Feasibility Study is critical to understanding how to protect inland neighbourhoods most at risk and unlocking resources to take action.
“I’m grateful for all our partners working to ensure Boston is resilient, prepared and beautiful.”
Climate change is already reshaping Boston’s coastline, increasing flood risks and putting critical infrastructure, homes, businesses and transportation networks in jeopardy.
Lt. Col. David MacPhail, deputy commander of the New England district of the USACE, called the release of the study a “major milestone” in the shared mission of community resilience.
“The reality is that doing nothing is not a viable option,” he said. “Without action, the costs to public safety and economic vitality from coastal flooding will only be compounded.”
Indeed, according to the USACE, more than 40 per cent of Boston residents, or approximately 284,000 people, live in areas at risk of coastal flooding.
Nearly 20,000 buildings could experience severe flood damage unless additional protections are put in place.
The danger extends far beyond waterfront neighborhoods, as floodwaters entering low-lying coastal areas could travel inland, threatening a number of communities and critical regional infrastructure, including Logan International Airport, the Massachusetts Bay Transportation Authority, Interstate 93, the Massachusetts Turnpike and several major hospitals.
The city has already experienced the warning signs. Since 1991, Boston has endured 24 severe storms that resulted in state or federal disaster declarations, with 14 causing major flooding.
The Army Corps evaluated a range of options to fight flooding, including building floodwalls, retrofitting buildings and concluded shoreline protection offers the most effective long-term solution. The draft plan outlines projects across five key waterfront areas. Together, the projects would close approximately 20 major coastal flood pathways where storm surges could otherwise penetrate deep into the city during major weather events.
Environmental conditions, cultural resources, historic features and future development plans were all considered in determining possible project locations and designs.
The study identifies a “Comprehensive System Plan” – essentially a co-ordinated network of protections designed to function as an integrated defence system across Boston Harbor. Recognizing financial and construction challenges, the USACE has also identified a number of smaller “Early Actionable Increment Elements” that could be built first as part of a phased approach.
Under current federal cost-sharing rules, as much as 65 per cent of eligible construction costs could be covered by the federal government, with the remaining 35 per cent requiring support from state, municipal and private-sector sources.
The cost of not taking any action could be substantial. Without intervention, Boston faces a troubling future.
USACE estimates that if Boston does nothing to improve its coastal resilience, cumulative flood-related losses could exceed $54 billion by the end of the century. In practical terms, the agency estimates that every $1 invested in coastal protection would save roughly $4 in future disaster losses.
The Army Corps estimates sea levels in Boston could rise by as much as four feet by 2090, and what are considered nuisance flooding events today are expected to become larger and more frequent. Neighbourhoods more than a mile from the ocean could face severe flooding within the next 25 years.
A major storm occurring later this century could flood more than 20,000 structures, disrupt transportation networks, damage hospitals and public facilities and cause widespread economic losses.
The draft study is not yet final. The Army Corps and the City of Boston are seeking public feedback before determining which projects move forward. Public meetings are being organized to help residents understand the options and provide input on project locations and designs.
The clock is ticking, though, as infrastructure like floodwalls take years to design and build. The plan is to complete the study by 2028.
