Time for a tunnel to island airport?

Seventy-two years after it was first sunk, the dream of an underwater tunnel connecting the mainland to the Toronto Islands is being floated again.

The Toronto Port Authority has asked for millions of the federal government's stimulus money to build a 120-metre pedestrian tunnel from the base of Bathurst Street to the Toronto City Centre Airport terminal, whisking people on moving walkways 27 metres underground.

It's an idea that has caught the imagination of city officials before. It was first proposed in 1935, as a $1-million project during the Depression. The idea divided the city, and was quashed by prime minister William Lyon Mackenzie King.

Sixty years later, then-mayor Barbara Hall resurrected the idea.Now, it's the TPA's turn. And the only thing blocking the project, the authority says, is a lack of cash. This time, estimated cost is $20-million to $40-million.

The tripartite agreement governing the airport allows for a pedestrian tunnel, says TPA chief executive Alan Paul. "We just need the money," he said.

The current tunnel proposal "is no more and no less than an idea," said TPA chair Mark McQueen.

It is not part of the port authority's capital works plan, and was belatedly added to a wish list for stimulus money the port authority submitted to Ottawa.

"If the federal government would like to proceed with a project of this nature, we'll be pleased to assist in its execution," he said.

The port authority sent its first list of "shovel ready" projects to federal Transport Minister John Baird in February.In May, the TPA sent a follow-up letter adding the tunnel as another "infrastructure opportunity."

The TPA says its construction - intended to be complete before the stimulus package deadline of March 31, 2011 - could piggy-back on a current City of Toronto plan to build a water main to the islands.

But the City has not confirmed it will construct the new water main. Toronto Water general manager Lou Di Gironimo says an environmental assessment is expected by the end of this summer, with no clear price tag yet and construction in 2011 at the earliest.

Early work on the environmental assessment suggests the utility tunnel that now crosses the channel would not be suitable to house the water main, he said.

"It is too confined and it is an old corridor," said Mr. Di Gironimo. "The costs will be significantly higher, so that we may have to revisit whether we do the project or not."

A spokesman for Mayor David Miller, who is out of town, said the TPA shared copies of its federal funding request letter late Tuesday, listing 18 potential options for infrastructure funding.

"They have not formally approached the city about this project," said Stuart Green, deputy press secretary for Mr. Miller. "We have not had a chance to review it. We don't know what it is."