Hull officials want the state to do something to save the failing state-owned seawall at Nantasket Beach before a disaster strikes similar to what happened along the New Jersey coast last year.
“The current condition of the seawall, and lack of sand in front of it, represents a significant problem,” Hull Town Manager Philip Lemnios said. “We’re hoping they don’t wait for an emergency to act.”
The concern echoes similar calls for seawall repairs from communities south of Boston. Marshfield’s public works director, for example, wants $5 million for seawall work, and the town is teaming with Duxbury and Scituate to study the best way to protect their shorelines.
In response to an earlier study that found 149 miles of seawalls along the state’s coast needed more than $1 billion in repairs, the Legislature approved a $17 million loan pool late last year to help pay for improvements.
“It’s a very expensive problem with lots of property at risk, and well beyond the means of most communities,” Lemnios said.
A 2012 study by the Metropolitan Area Planning Council, for example, found that Scituate faced a $33 million bill to upgrade publicly owned seawalls and other structures protecting its 12 miles of shore into acceptable condition.
The same report said Marshfield could spend $22 million upgrading its protective coastal infrastructure. Duxbury, which has several seawalls in critical condition, could spend $2.8 million to repair the substandard structures along its 4.7 miles of shore, the report said.
In Hull, the sand in front of the 5,500-foot-long seawall at Nantasket Beach has been steadily eroding. The wall was built in pieces between 1916 and 2008, with the majority of construction taking place between 1930 and 1945, according to SJ Port of the state Department of Conservation and Recreation.
“If you look at photos from 40 years ago, there [was] sand 2 feet below the wall,” Lemnios said. “Now there’s a 10- to 15-foot drop; there’s been an incredible amount of erosion along that stretch.”
In addition to the loss of usable beach, the erosion threatens the stability of the seawall, he said.
“One of the functions of sand was to support the seawall,” he said. “It’s no mystery that the footings of the structure are exposed to a much greater degree than engineering anticipated.”
The solution proposed by the town’s appointed Beach Management Committee is to move the wall back 30 to 40 feet, a recommendation the committee said it took from direct observations and a report by the Army Corps of Engineers. Total cost is estimated at $70 million, Lemnios said; Port gave a figure closer to $30 million.
“It’s very much a long shot because of the upfront cost,” acknowledged Beach Management Committee member Paul Epstein. “But it’s the only way to save our beach.”
He said the seawall problem not only is causing the beach to disappear at Nantasket, but is also ruining the town-owned beach farther down the peninsula, as sand is pulled away to replace the void.
While moving the wall would eliminate parking spaces, not moving the wall would eliminate more than that, he said.
“If we do not have a usable beach, we have no businesses,” he said.
Epstein said the town needs to go on record with its recommendation “so at least [the state] will not be able to tell us that we did not give them our opinion,” a view that selectmen endorsed at their Jan. 8 meeting when they agreed to write to the DCR to start a conversation about the problem.
The state DCR has no money in its budget for any immediate work on the wall, Port said. The last repairs, in 2008, cost about $4 million for work on about 1,000 feet of seawall, she said.
The agency is not convinced, however, that moving the seawall back would solve the erosion problems at Nantasket, she said. Instead, the DCR prefers a different approach, concentrating first on reducing direct wave action on the seawall by putting a revetment, or boulders, in front of it, she said.
The state has put boulders at the edges of the Nantasket seawall and successfully eased erosion there, she said.
The DCR plans to extend the revetment protection to the middle of the wall as well, with the Army Corps of Engineers providing half of the $4 million cost.
The second phase of the state plan would be to bring in sand to rebuild the beach, at a cost of about $17 million, Port said.
Rebuilding beaches is common practice in places like New York, California, and Florida, Port said.
“This would give Hull full protection from a 10-year storm, severely limit damage from a 100-year storm, and bring back a high-tide beach along the whole length of the state reservation,” she said.Continued...