LOCKPORT – The 95-year-old North Adam Street bridge over the Erie Canal ought to be preserved, Mayor Michael W. Tucker said during his State of the City address last week.

But doing so in a way that allows the bridge to be reused is a heavy financial challenge.

Susan Surdej, spokeswoman for the state Department of Transportation’s Buffalo office, said construction of a replacement bridge costs about $7 million, not counting the design costs or the costs of removing the old bridge, which are estimated to be between $500,000 and $1 million.

Repairing the existing span would cost $7.5 million to $8 million.

“And then we would have to identify funding for the feasible alternatives. Right now, we haven’t identified any funding at all,” Surdej said.

“The DOT is throwing some pretty big numbers around,” Tucker said Tuesday during his speech to the Lockport Rotary Club.

“They’re trying to present the case that it’s cheaper to take it out than to repair. I don’t want it to come out.”

The lift bridge was closed April 28, 2011, in the “up” position, after a DOT inspection disclosed deterioration in the bridge structure and lift mechanism.

At a public meeting Nov. 29 in City Hall, DOT representatives heard that residents want to keep the bridge, even though another lift bridge over the canal, on Exchange Street, is only 1,030 feet away.

Both spans run off Market Street in the city’s Lowertown district.

“We are still in that initial scoping process,” Surdej said. “We continue to get public comment, so we’re still sifting through that.”

By summer, she said, the DOT will be done considering alternatives and will move on to designing and obtaining firmer cost estimates for the alternatives its staff considers feasible.

Tucker said he has asked Robert J. Hagen, chairman of the city Historic Preservation Commission, to look into ways of saving the North Adam Street Bridge.

Hagen said he intends to write “a letter of advocacy” to the DOT, emphasizing Lockport’s status as a “certified local government” for historic preservation purposes.

He said he thinks the bridge should be repaired, but he admitted, “Some of the parts and pieces they need to fix it don’t exist anymore.”

Asked how repairs can be done without the needed parts, he said, “We have some innovations in our mind,” but he wouldn’t disclose them.

Surdej said one option discussed was converting the bridge to a pedestrian walkway and forgetting about using it for vehicular traffic, or just turning it over to the city. “They’re not willing to take over the maintenance costs of this bridge,” she said.

Even the demolition figure has grown radically from the $200,000 to $400,000 estimate used by DOT scoping supervisor Christopher Church at the Nov. 29 Lockport City Hall meeting.

In 2000, the DOT spent $300,000 repairing the lift mechanism on the North Adam span. Church said the company that provided the new lift mechanism apparently has gone out of business.

That same year, the DOT built a new Exchange Street bridge for nearly $5 million. The old Exchange Street bridge, which had deterioration similar to that on the North Adam span, had been shut down in 1993.

At the Nov. 29 meeting, several residents referred to the historic nature of the North Adam span.

Surdej said, “The bridge itself isn’t considered historic by the state Historic Preservation Office, but it’s a contributing historic element to the historic Erie Canal.”

The state closed the 1910 Prospect Street bridge over the canal in December 1991 and replaced it in 2005 with a new bridge at Stevens Street, also of steel design but wider and longer than the old one. Historic preservation concerns had an impact on the design decision.

The North Adam and Exchange bridges open in the middle to allow boats to pass. The most frequent reason for opening them in recent years has been the passage several times a day of tour boats from Mike Murphy’s Lockport Locks and Erie Canal Cruises.

However, the state normally used only one bridge tender.

“It’s a hoot when Mike Murphy’s tour boat comes through and he raises the bridge, and then he jumps in his car and goes to raise the other one,” Hagen said. “It’s part of the character of our city.”