MONROE — The antiquated Route 34 bridge positioned atop Stevenson Dam, which links Monroe to Oxford, will be closed to traffic for a 90-hour period to allow for maintenance work on the hydroelectric dam at the Housatonic River, which has been in service for nearly a century.

In a statement, FirstLight Hydro Generating Company said the bridge’s closure will require that detours be used while maintenance work is underway.

The bridge atop the dam will be closed to traffic starting at 6 am on Saturday, May 2. It is scheduled to reopen to traffic at 12:01 am on Wednesday, May 6.

Traffic will be detoured using Route 111, Route 110, and Bridge Street in Shelton, according to FirstLight.

Long-distance traffic is advised to use Route 8 and Interstate 84 to avoid the bridge at Stevenson Dam while maintenance work is underway.

Many Newtown motorists use the Route 34 bridge in traveling to and from the New Haven area.

Electronic message boards are posted in the area near the dam advising motorists of the planned bridge closure.

First Light spokesman Leonard Greene said April 22 that works crews will seek to finish the maintenance project as quickly as possible.  If the work is completed sooner than planned, the bridge would be reopened to traffic sooner than is scheduled, he said.

Stevenson Dam started hydroelectric operations in 1919. The dam atop the bridge is one of the few river crossings in this area.

The roadway atop the bridge is narrow by modern standards and has very tight turns at both ends of the bridge, making travel there by tractor-trailer trucks difficult.

While the state owns the Route 34 roadway positioned atop the bridge, FirstLight owns the bridge itself and the dam upon which the bridge is positioned.

The state Department of Transportation has made several attempts during the past two decades to create a modern new bridge across the Housatonic River near Stevenson Dam to replace the antiquated bridge, but for one reason or another, the project has never materialized.