A new federal study is detailing 20 potential projects to protect Boston against rising seas and coastal flooding — including miles of flood walls and berms that could include a major revamp of the Harborwalk by the Fort Point Channel.
The U.S. Army Corps of Engineers will release the full study on Friday, which includes plans for projects along 16 miles of the city’s coastline.
Boston Mayor Michelle Wu announced the study and its proposals Monday at a press event in the North End’s Langone Park.
“More than 40% of our residents now live in areas at risk of coastal flooding, including some communities who are more than a mile away from the ocean,” Wu said. “Without action, we risk more than $54 billion in damages to our homes, hospitals, businesses, roads and other critical infrastructure by the end of the century.”
Lt. Col. David MacPhail of the Army Corps of Engineers said at Monday’s event that they’ve been partnering with the city to work on the report for four years.
“Doing nothing is not a viable solution,” MacPhail said. “Without action, the cost to public safety and economic viability from the coastal flooding will be compounded and untenable.”
The projects’ cost is expected to come out to about $10 billion in total, and the federal government will cover about 65%. The rest would come from state and local government, or private partners.
Brian Swett, Boston’s chief climate officer, says that figure needs to be contextualized with another figure: an estimated $40 billion that could be prevented in economic losses due to flooding.
“When we talk about ‘Why is the federal government interested in spending money now versus later?’ — that’s the ratio that you look at,” Swett said. “To say: There’s a really big interest in spending now because we can protect on the order of 4-to-1 going forward of what would be the economic losses.”
One-sixth of Boston sits on filled tidelands.
“A lot of the area that used to be, in its original form, underwater — that’s a lot of the areas that we see most susceptible to flooding in the future,” said Nayeli Rodriguez, the city’s deputy director for the office of climate resilience. “It’s not just a coastal problem either. Forty percent of Boston is at risk, including a lot of the inland neighborhoods — places like my neighborhood in the South End, parts of Dorchester, even Allston.”
They’re all important, she said, because they protect access to infrastructure that’s critical to all of New England.
“We have a ton of transportation infrastructure, a lot of health care and medical infrastructure that people outside of the city, outside of even our immediate Boston area, rely on all across the state,” she said.
One of the infrastructure improvements that will be recommended in the report is a storm surge barrier in the Fort Point Channel, Swett said.
“That provides some really great benefits of preventing the stormwater there from going in, but also dealing with torrential rain issues,” he said. “And we can actually control the Four Point Channel Basin in ways that we can’t today and potentially use it to house stormwater coming from Boston before it can get pumped out into the harbor.”
That project would be one of the later ones tackled, Swett said — likely sometime in the 2040s.
The proposed projects will be open to public comment until mid-September, and the report is expected to be finalized by 2028.
