Safety concerns over an antiquated stone culvert prompted the emergency closure of a portion of Acushnet Road on Thursday afternoon. Highway Surveyor Barry Denham anticipates that the area, adjacent to Tinkham Pond, will remain closed to traffic for at least a month.

Denham estimates that the culvert is about 150 years old, and in recent months it has been showing its age. A few months ago a dip in the road developed where two of the large stones beneath the pavement have begun to sag and lean on each other. As winter comes, those stones will become more brittle and likely to crack, said Denham.

“Those are liable at some point just to go down. Whatever damage happens at that time we can’t predict,” he said.

The area was on Denham’s list of road repairs for this year, which received a $275,000 appropriation from Special Town Meeting voters on Monday night.

On Tuesday, engineers inspected the culvert. The Department of Transportation was also consulted. Both recommended closing down the road on Thursday.

“We’ve known we had to replace this culvert,” he said. “This has just accelerated this project to the top of the list.”

Although the area has flooded before, Wednesday night’s storm was not a factor in the decision, said Denham. Were the stones to collapse under the road, it could cause a car to swerve into the brook below the culvert or worse. Denham said school buses use the road daily.

“It’s a dangerous location. There are no guardrails. We need to widen this area out somewhat so we can get some decent guardrails in,” Denham said.

He said it will take around nine months to acquire the permits needed to replace the culvert.

In the meantime, Denham hopes a temporary fix can be put in place. DOT bridge engineers came to inspect the site on Thursday and to give Denham an idea of what options there are to reopen the road. It is likely to take at least a month, he said.

“It’s a major inconvenience for a lot of people, but we have to be safe,” said Denham.