A bit of Toronto's buried history has bubbled to the surface in recent weeks.
Just under the south end of the bridge over the rail yards at the foot of Bathurst Street, there's a pool of clear water, a couple of feet deep in places.
Jo Ann Pynn, the museum administrator at Fort York, said that most springs, "there has always been a small puddle or pond, depending on the season, there under the bridge, which has come and gone." But this year, the pool is deeper, the water is still flowing, and it looks like it might be hanging around for the summer.
City officials are scrambling to determine the source of the aquatic eruption, but some already believe they are witnessing the re-emergence of Garrison Creek, a once-prominent stream that cut a 7.7-kilometre swath across the west end until the late 19th century, when it was diverted into a sewer in the interest of public health.
When city workers went to look at the pool, they found the water was too clean to be the usual spring runoff of melting snow. "It was so clear actually that one of the guys from [the]works [department]thought a water main had burst," said David O'Hara, a city parks planner. "There's a good bit of water down there."
When it was tested, scientists found it was not tap water from a water treatment plant but fresh groundwater, water of the kind that flows down a myriad of creeks and rivers into the Great Lakes.
Maps of the city from the first half of the 1800s show that Garrison Creek flowed out of the hills to the west of the height of land on which Casa Loma is located and down to Lake Ontario at Fort York, which was then on the shore of the lake. There the creek turned east to run along the north side of the fort, and entered the lake just about where the Bathurst Street bridge is today. Landfill has since altered the topography, creating an artificial shoreline south of the natural outlet.
Ms. Pynn said that "the creek was put into a large sewer in the 1860s, so its route was changed. So it's somewhat under its original route as it comes through the city."
Despite the realignment, the creek still passes beneath some west-end parks, such as Trinity Bellwoods and Christie Pits.
When sewers were installed in the vicinity of Fort York, they were put 3.6 metres underground at the west end of the fort, rather than following the natural drainage line to enter the lake east of the fort, as the creek had done. It was at that old creek mouth that the small pool started appearing each spring. "We, over decades, have speculated about it being Garrison Creek. Or not. But it was in the right place to be the creek," Ms. Pynn said.
This spring's flow has raised a number of questions that the city has now set out to answer.
Mr. O'Hara speculates that the underground drainage in the area has been disturbed by extensive grading and earth movement on the railway lands this winter. The result of all this movement is a 10-metre-high pile of earth on which a new street will eventually be built.
The most intriguing question is, might there be a water flow sufficient for Garrison Creek, even in a remnant form, to be part of the landscaping that will go in front of Fort York or the new public housing that is part of the redevelopment of the rail lands?
While the prospect has both Mr. O'Hara and Ms. Pynn dreaming about watery vistas, the city, Mr. O'Hara said, has only begun to study the issue.
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