LEWISTON — The city is pursuing federal funding to build an extension of the riverwalk under Longley Bridge, considered a critical step in a goal to connect Veterans Memorial Park and Simard-Payne Memorial Park.

Officials say the 350-foot span is the most complicated and costly portion of the riverwalk, which is why they’re submitting the $3.4 million project to Maine’s congressional delegation.

Completing the riverwalk is one of the main goals of the city’s updated Riverfront Island Master Plan, which the city is using to drive redevelopment of the historic mill district along the banks of the Androscoggin River.

The city has already received federal funds toward similar projects, including Simard-Payne Memorial Park improvements, and another section of the riverwalk south from Simard-Payne park, across the site of the future Maine MILL, and across the redeveloped Continental Mill property to Cedar Street.

Nate Libby, director of economic and community development, said the Longley Bridge underpass project has several benefits that align with the city’s larger goal of better connectivity to riverfront areas, especially as redevelopment occurs and more people are utilizing them.

He said the underpass will carry pedestrians and cyclists safely under a busy Main Street corridor that sees some 30,000 vehicles a day, and will allow the city to pursue riverwalk connections north as well. In a memo to the council he said it will also “mirror the riverwalk investments Auburn has enjoyed and connect the two communities by pedestrian pathway.”

The riverwalk is a quarter-mile-long path from the Auburn riverwalk bridge at Simard-Payne Memorial Park to the parking lot behind the Hampton Inn.

According to the Riverfront Island Master Plan, “extending this path further is intended to create connections to Island Point and Sunnyside Park to the north, and Lown Peace Bridge, Little Canada and points beyond to the south.”

The City Council voted unanimously Tuesday to direct city administration to pursue the funds, which Libby said will be sought by U.S. Rep. Jared Golden, D-2nd District.

Councilor Josh Nagine said the project will make Veterans Memorial Park more accessible at a “high-crash site” in the city. He pointed out that he’s seen people running across the road to get to events.

“The public safety aspect as well as accessibility to our public spaces is going to be a fantastic addition to the riverwalk,” he said.

Mayor Carl Sheline said Tuesday that “development of our riverfront is a top priority for the city and we have long envisioned a continuous riverwalk connecting Simard-Payne and veterans park.”

A memo to the City Council says the underpass project and its proximity to the river’s edge “poses some engineering complexity” that results in the high price tag.

Libby said the section would essentially be a 10-foot-wide pedestrian bridge under Longley Bridge that is set on “micro piles” to avoid impacting the existing bridge abutment, “reducing environmental impacts and providing flood resistance.”

When asked when the city would expect to be notified about the congressional funding award, Libby said “best case” would be in the next nine to 12 months, especially with the current uncertainty in Washington. He said the city “can work with our engineers and planners to start moving on the project while the rest of the process moves along.”