Norwich – Just days after Mayor Peter Nystrom warned state transportation officials that heavy construction to create six roundabouts on Route 82 could damage aging water mains, a nearly 100-year-old main broke early Monday, closing the busy commercial strip for several hours.

Norwich Public Utilities said the 10-inch diameter water main, installed in 1926, at the West Main Street-Osgood Street intersection broke about 12:30 a.m. Monday. Water service was disrupted to 13 customers and forced officials to close the road to traffic to repair the break. Water service was restored by mid-morning, NPU spokesman Chris Riley said, but the road remained closed for much of Monday for repairs.

The intersection is one of six sites where the state Department of Transportation plans to replace traffic lights with roundabouts. The Osgood Street roundabout is proposed for the first phase of the two-phase, $45 million project that would run from Fairmount Street west to the area of Salem Plaza. DOT project officials held a public informational meeting on the project Thursday at Kelly Middle School.

NPU officials said the water line was in a fairly shallow trench, possibly because of ledge beneath the surface.

“Nearly 100 years of traffic, wear and tear are likely the cause of the water main break,” Riley said in an email Monday.

During last week’s informational meeting, Nystrom told the DOT project crew that the city water lines beneath the 1.3-mile strip where the reconstruction would take place are 100 years old and could be damaged with the digging and heavy equipment needed for the construction project. Nystrom said DOT should replace the aging lines prior to the project, warning that if nothing is done, a weakened line could burst sometime after the new pavement is laid down.

Nystrom said he visited the break area Monday morning and planned to contact DOT project officials and the commissioner’s office to repeat his call to have DOT replace the line if the project goes forward.

“It’s going to be repeated,” Nystrom said of a water main break, “if we don’t take care of it now.”

DOT spokeswoman Shannon King issued a statement Tuesday in response to the mayor's request.

"The safety improvements project on Route 82 in Norwich (Phase 1) is currently in the preliminary design phase," the statement said. "The public comment period ends July 7. As the project progresses, CTDOT will work closely with Norwich city officials to evaluate the project impacts on underground utilities, including water mains."

Riley said NPU has developed a preliminary estimate of at least $8 million to replace the water main along West Main Street in conjunction with the roundabouts project. Riley said there may be state or federal funding to assist with the project.

“We will continue to evaluate how best to move forward in a way that benefits NPU, the city, and our community,” Riley said.

DOT project officials were not available immediately for comment Monday.

c.bessette@theday.com