MONTAGUE — The South Street Bridge closed on Monday, marking the start of a $4 million bridge replacement project funded by the Franklin Regional Council of Governments (FRCOG) Transportation Improvement Program.

The bridge will remain closed until June 2025, according to Assistant Town Administrator Chris Nolan-Zeller.

“The only road being closed for this particular project is South Street at the bridge over the Sawmill River,” Nolan-Zeller said. “Nobody is going to be impeded from accessing their homes on South Street, but people are going to need to go around the bridge.”

Nolan-Zeller advised that one detour is to go north up Turners Falls Road to Swamp Road to access Route 63. Another option is to go south on Main Street until the intersection with Routes 47 and 63.

“It will be an inconvenience to some folks for a year, unfortunately, but I think the outcome will be good with the much more sufficient bridge in place,” Nolan-Zeller said.

The replacement bridge will be 58.5 feet long, with two 10-foot lanes and abutments positioned farther from the river’s flow than is the case presently. The existing bridge was reduced to a single 12-foot lane of traffic in spring 2018 and has abutments that are largely in contact with the water. The bridge is being raised as much as possible to accommodate the swelling of the Sawmill River during storms and shifting water levels in the wake of climate change.

Erin-Leigh Hoffman can be reached at ehoffman@recorder.com or 413-930-4231.