WATERVILLE — The Western Avenue bridge will close beginning at 6 a.m. Tuesday for reconstruction, a state project that the city welcomes.

It is scheduled to reopen at the end of August.

The 68-year-old bridge is old and is in need of replacement, said state Department of Transportation spokesman Ted Talbot.

The department is overseeing the project, which is expected to cost $738,000.

Waterville Public Works Director Mark Turner said Monday that the state transportation department has jurisdiction over the bridge, as it does with nearly all bridges in the state, and the city is not involved in the reconstruction project. Western Avenue is a state-aid road, Turner said, meaning the state funds improvements.

John Stetson, of contractor Stetson & Watson, the group that is doing the reconstruction, said the bridge is not unsafe, but is aging and has a reduced weight limit for large trucks.

Turner said once the project is completed, the bridge will be safer for both motorists and pedestrians. The completion date is set at Aug. 27.

“We’ve been involved in the public hearings, but we really haven’t had a lot of input or involvement in the project design or advertising or planning, but we are supportive of the project and we know it will be beneficial,” he said.

Turner said that several years ago the state installed metal plating over the grates on the bridge because some had corroded, and later the plates came loose and new plating was added to replace the old ones.

“It was time for things to be comprehensively repaired or updated,” he said. “I think in the long term, it’ll be better for the structure itself to be upgraded.”

A detour will be in place from First Rangeway to Mayflower Hill, Pleasant Street and back to Western Avenue, according to the state transportation department.

City motorists use Western Avenue and the bridge as a route between Elm Street and Kennedy Memorial Drive.