‘This is Boston’s big challenge’: A new plan to defend downtown against sea-level rise

The long-awaited plan aims to protect about $3.9 billion in crucial downtown infrastructure, including the Central Artery Tunnel and its entrance, the Harborwalk, tunnels for the MBTA’s Silver and Blue lines and the Aquarium Station, the Rose Fitzgerald Kennedy Greenway, historic buildings, and the city’s electric grid, said Marc Margulies, president of the council, which represents property owners and businesses in the area.

“We have a responsibility to the city of Boston to come up with a workable plan,” Margulies said. “It doesn’t matter what development you do or don’t want to happen. The ocean doesn’t care about our politics. It’s coming anyway.”

Funding for the study came from waterfront property owners and the state, which last year allocated $250,000. Another $250,000 was included in the House version of next year’s budget, though not the Senate’s. That funding proposal is now heading to a conference committee, which will start next week.

“We have to really start nailing down and getting more serious about plans that will prevent us from being underwater, or having a difficult quality of life along the waterfront,” said state Representative Aaron Michlewitz, who represents the Wharf District and chairs the House Ways and Means Committee. “The lifeblood of the economy ... trickles through downtown. And without a real game plan, not just from the city but from the state and from all the interested parties, we could certainly be putting that economic lifeblood at risk.”

The state funding was a key bridge to resiliency planning, particularly as Boston’s municipal harbor plan was nullified.

That plan, long debated and finally approved under former mayor Martin J. Walsh, allowed for an often-critiqued 600-foot tower to be built at the site of the Boston Harbor Garage. That plan eventually got state approval, but had been blasted by advocates who contended it focused more on development than climate-change preparedness. In 2021 acting Mayor Kim Janey took steps to rescind it, saying it did too little to address resiliency and equity, and it was scrapped entirely after Mayor Michelle Wu took office.

Representatives from Wu’s office and the Boston Planning & Development Agency declined to discuss the Wharf District Council plan or its potential impact on the downtown waterfront, e-mailing a statement that said: “The resilience plan is separate from and doesn’t require an update to the Municipal Harbor Plan.”

A likely next step, the city spokesperson said in an e-mail, is to “review this plan through the City’s partnership with the Army Corps of Engineers,” which is studying resiliency efforts across the city — including a potential storm surge barrier underneath a future Northern Avenue Bridge.

The first steps in the Army Corps’ plan are to meet with waterfront communities and to develop a resiliency plan for Boston’s five waterfront neighborhoods by 2026. Margulies said the council’s aim is for its plan to give the Army Corps a “running start” at developing its own plan and budget.

In the near term, the city is looking at “more immediate work at Long Wharf,” the city spokesperson said. Wu has allocated $6 million in the city’s proposed budget to improve resiliency at Long Wharf, which now routinely floods during so-called King Tides, the waterfront’s highest annual tides.

The total cost estimates outlined in the wharf plan were “eye opening, to say the least,” Michlewitz said, as were the flood maps that laid out in detail what could face inundation in the coming decades. It’s too early to tell how the efforts might be financed, he said, adding that it would be an “all hands on deck” endeavor requiring support from the city, state, and federal governments, as well as the private sector.

“We don’t want to get ourselves into a fiscal challenge for the next generation,” Michlewitz said. “But we have a climate challenge for the next generation that we have to solve.”

One key player, the New England Aquarium, called the council plan a “pioneering effort” that requires bringing together multiple stakeholders.

“We’ve been really hyper-invested in this, because it’s crucial that we do something proactively, as opposed to waiting for, say, some other storm that’s going to have a monumental and devastating impact,” said Rick Musiol, the aquarium’s vice president of external relations. “We’ve got to get ahead of it. This is Boston’s big challenge.”

The aquarium’s long-envisioned Blueway, a plan for a resilient Central Wharf, is not mentioned specifically in the new report. The Blueway is “part of a larger conversation ... once we figure out what that resiliency effort looks like,” Musiol said.

Some of the Wharf District Council members have long been at odds over proposed waterfront development. But the collaboration can be a model for other municipalities’ resiliency plans, said Duna Chiofaro, vice president of The Chiofaro Co., the real estate firm behind the proposed tower at the Harbor Garage.

“It’s a necessary step, certainly for this neighborhood, to get on the same page,” he said.

Bud Ris, chair of waterfront advocacy group Boston Harbor Now and senior adviser to the Boston Green Ribbon Commission, helped create the Wharf District Council. In his view, the plan does two important things: It says what the city needs to do between waterfront buildings to protect the Greenway and the Financial District behind it, and it improves public access to the waterfront, rather than building a storm wall that blocks off all connection.

Federal funding for such large projects can take decades, Ris noted, and in the meantime, sea levels continue to rise. Spreading the costs of flood-protection measures to include the owners of downtown buildings could determine “who will benefit from it, and therefore what responsibility they have to pay for it,” Ris said.

“The private sector has an obligation to pay, because it’s going to benefit from this big time,” he said. “You’ve got to look at areas who will benefit inland.”

Ris suggested creating a state-managed governance or financing commission to oversee climate resilience efforts — not just in Boston, but across other waterfront municipalities — though, he said, that could be tricky from a permitting and regulatory standpoint.

“What sort of entity do we need to make sure everybody’s doing their part?” Ris said.

Catherine Carlock can be reached at catherine.carlock@globe.com. Follow her on Twitter @bycathcarlock.