The Department of Transportation said it plans to begin replacing next year the nearly 90-year-old bridge that brings Route 1 over the Niantic River between East Lyme and Waterford.

Construction is scheduled to start in April 2016 and finish in November 2017, according to the state Department of Transportation.

The new upgraded structure will replace the existing concrete bridge built in 1926, the DOT said.

"Inspections and engineering analyses indicate that the bridge is structurally deficient, hydraulically inadequate, and functionally obsolete, and that it should be replaced in its entirety with a new structure to maintain public safety and traffic flow and protect the local and downstream environments," a project description from the DOT states. "The proposed reconstruction of the bridge will include necessary upgrades to safety components and improved stormwater management features."

The new bridge's design is slated to be completed this week, according to the DOT.  

The DOT is proposing a bridge with two 12-foot lanes, along with one 10-foot shoulder and one 5-foot shoulder, according to the DOT's April application to the state Department of Energy and Environmental Protection.

The proposed bridge would have a reinforced concrete deck supported by steel stringer beams.

The bridge would also have cast-in-place concrete abutments and micropiles drilled into bedrock, according to the application.   

The state DEEP issued this month a draft permit for the DOT to replace the bridge and conduct work below the coastal jurisdiction line or within tidal wetlands. The DEEP will accept comments on the proposal until Sept. 11.

The DOT will go out to bid in November for the project anticipated to cost roughly $4 million, said DOT spokesman Kevin Nursick. The DOT expects federal funds will cover 80 percent of the project, while the state will contribute 20 percent.

Nursick said the project will proceed in three phases so that vehicles can continue to move in both directions throughout construction.

k.drelich@theday.com

Twitter: @KimberlyDrelich