By SCOTT JACKSON
Quincy is planning to replace 8,000 linear feet of seawall between Adams Shore and Houghs Neck with a taller structure meant to better repel the ocean, but some residents say the current plan does not go far enough.
City officials and representatives from Tighe & Bond, the engineering firm working with Quincy to design the new seawall, outlined their plans for the project during a community meeting Wednesday at City Hall. More than 100 residents were in attendance.
The seawall along Quincy Bay would be done in two phases, with the first phase taking place from Chickatabot Road to Babcock Street. The second phase goes from Babcock Street to Bayswater Road.
The project requires approval from seven different federal, state and local permitting bodies, including the Quincy Conservation Commission, which is slated to hear the proposal at its meeting Sept. 5. Chris Walker, the chief of staff to Mayor Thomas Koch, said there is no timeline yet for construction given the number of permits the city must obtain.
“The construction timeline will come when design and permitting are several steps down the road,” Walker said.
David Murphy of Tighe & Bond said the first phase is expected to cost up to $8.5 million. The total cost for both phases could exceed $15 million, Walker said. The city will seek state and federal money to complete the project – a state grant and matching funds from the city are paying for the design of the new seawall – but Koch is committed to the replacing the seawall even if no outside funding is secured.
“It’s not contigent on state or federal funding,” Walker said. “Whatever level of state and federal funding we get – that’s terrific. If there is no state or federal funding, the mayor fully intends to be in front of the City Council with a borrowing request for whatever needs to be done.”
The current seawall and stands, on average, 11 feet above mean sea level. Initially, Tighe & Bond planned to construct the new seawall two feet higher, Murphy said, but Koch asked the seawall be built four feet higher – a total of 15 feet above mean sea level – following this winter’s severe nor’easters.
Murphy said the worst predicted annual high tide – also known as a king tide – is 6.9 feet above mean sea level. The storm surge from the Jan. 4 nor’easter – the highest high tide Boston has seen – was 9.5 feet above mean sea level, with another four feet of wave action on top of it.
The proposal would include a leveling slab of concrete on top of the revetment currently in place, up to the elevation of the existing wall, Murphy said. The base would be six-feet wide. A seven-foot-tall, 12-inch wide section of pre-cast concrete would then be bolted to the outside of the wall facing the sea to provide the extra four feet of height. That would also create a 4.5-foot-wide walkway along the inside of the seawall on top of the concrete slab; railings would be installed on the walkway.
To provide access to the waterfront below the seawall, cut outs would be made in the wall itself, leading to staircases. The Department of Public Works would be responsible for inserting storm boards into the cutout sections ahead of storms if wave action were expected to surpass 11 feet above mean sea level. The number of such access points is still being determined.
The proposal would also include pipes every 30 feet along the seawall to drain floodwater into the ocean. The pipes would have one-way valves to ensure seawater does not permeate the wall.
Residents who spoke at the meeting said they were concerned about the design and whether it would be strong enough.
Dan Shea, an Adams Shore resident, said a wider wall without the railings and walkway would provide better protection while also minimizing maintenance costs in the future.
“I’m not sure this design is the right design,” he said. “You’re creating more maintenance for the city and more money down the road with the railings because we know they all fail within 10 to 15 years with the salt water hitting them all the time.”
Stuart Schrier, who also resides in Adams Shore, wanted to know if seawalls with a design similar to the one proposed along Quincy Bay have been constructed elsewhere.
“I think everyone is underestimating the power of the ocean,” he said. “We don’t want to be the guinea pig. Can you give us the history of those scrawny little blocks? If they’ve been in place for 20 years and they’ve withstood some storms, that might give us some confidence that that system could work.”
Duncan Mellor, an engineer with Tighe & Bond, said a similar seawall is located in North Hampton State Park in New Hampshire.
Murphy, in response to questions from residents about whether it would be possible to construct a new “jersey barrier” type seawall like the one in place now, but taller, said that would be feasible.
“That’s feasible to do,” he said. “We can increase the size of this leveling slab, bring that up to this elevation, and put new blocks like that – the ones you see all along – on top. That’s a design that is possible.”
Ward 1 Councillor David McCarthy said he plans to hold several meetings on the seawall to help come up with the best design possible.
“We live on the water, we live on the marsh, and it’s never going to go away,” McCarthy said. “We’re here to help, we’re here to defend it the best we can. Mother Nature might not care about anybody’s design in here and we’ll all be back here in a while, but we hope one design…will come out of all this and we can move forward.”