Resiliency measures such as a living shoreline that restored coastal habitats to the East Boston waterfront for the first time in 150 years are integrated into the 478-unit Clippership Wharf development. Photo by Ed Wonsek

East Boston’s new city councilor pressed officials to focus on city-wide resiliency strategies to confront the threat of rising sea levels, while the New England Aquarium pushed for a broad cost-sharing formula for multi-billion-dollar projects protecting the waterfront at a Boston City Council hearing Thursday evening.

Officials said the prospect for using American Rescue Plan funds to subsidize resiliency projects will play into the decisions over cost-sharing.

“We can’t approach this effort the way we approach our smaller mitigation projects. What’s needed is a much grander and broader attack on this issue,” Boston Planning and Development Agency Director Arthur Jemison said. “It’s going to take billions of dollars, the same way the harbor clean-up took that same amount of resources.”

At a hearing of the council’s committee on planning, development and transportation requested by District 1 City Councilor Gabriela Coletta, Jemison said the city’s resiliency strategy will include “proactive waterfront zoning and predictable entitlement processes.”

In the past, developers have designed their own resiliency strategies for individual parcels.

The Flatley Co. is proposing a new flood barrier on the Mystic River in its proposed 1.8-million-square-foot redevelopment of the former Domino Sugar factory at 425 Medford St. in Charlestown.

But waterfront advocates have criticized the parcel-by-parcel approach to coastal defenses as ineffective, because it can shift flooding onto other properties.

The time for a fragmented approach has passed, Jemison said.

“I can tell you one of the reasons this is such a challenging topic is not every owner is willing today or has the resources to protect their properties from inundation. This is where the discussion needs to happen,” he said.

In its first major resiliency project, the BPDA in January proposed a $20.5-million flood barrier on the east side of Fort Point channel. The 6-foot-tall, 45-foot-wide berm would run for 0.4 miles between 15 Necco St. to Dorchester Avenue, protecting 31 buildings including the Gillette Co. campus and several active and potential future development sites. Boston has applied for a $10-million FEMA grant to offset the cost.

The BPDA also is requiring private developers who are building projects in the publicly-owned Raymond L. Flynn Marine Park to pay into a new resiliency fund.

The New England Aquarium has opposed Boston-based Chiofaro Cos.’ proposal for a 900,000-square-foot skyscraper at the nearby Harbor Garage property on East India Row, citing negative impacts to its operations. The proposal hinged on rezoning of the downtown waterfront, which was overturned by a Suffolk Superior Court judge following lawsuits filed by Conservation Law Foundation and trustees of the Harbor Towers II condominium tower.

Rick Musiol, the aquarium’s vice president of external relations, said the threat to coastal properties requires a city-wide commitment on the scale of the Boston Harbor clean-up.

“If you have various properties moving forward with different resilience projects and they don’t link up together, you’ve created a scenario that may not achieve its ultimate goal,” Musiol said in an interview.

The funding formula should be spread beyond the waterfront to inland properties that would benefit from resiliency projects, Musiol said.

A 2020 Green Ribbon Commission report suggested that the city create a single or multiple districts that borrow money for resiliency projects, to be paid back through assessments on property owners.