The stone-clad outfall of the Belt Line Sewer, at the top end of the Vale of Avoca, just south of Mount Pleasant Cemetery.

Belt Line Sewer

Yellow Creek
Forest Hill storm sewers and CSO

Year of Construction:

Construction Details:
A mix of round concrete pipe, horseshoe and A-shaped arches, and a very old stone culvert beneath Yonge Street.

Also Known As:
"St. Clair Drain"
"Corpse Slime Drain"

Further Reading:

Archival Material:

East of Yonge Street and north of St. Clair Avenue, a drain runs out of Mount Pleasant Cemetery into the Vale of Avoca, feeding one of the remaining open stretches of the Yellow Creek. In her novel Cat's Eye, Margaret Atwood wrote about Mud Creek, just to the east of here, which shares with the Yellow Creek a similar landscape and contemporary provenance, as both now emerge from beneath the cemetery. Atwood's narrator in Cat's Eye describes her perceptions of the creek:

The water of the creek is cold and peaceful, it comes straight from the cemetery, from the graves and their bones. It's water made from the dead people, dissolved and clear, and I am standing in it.1

Like Mud Creek, the Yellow Creek is full of ghosts now. There are the ghosts of so many citizens of Toronto, great and small, buried in the burgeoning cemetery. There is the ghost of what was once a much greater creek, running down from Downsview, before it was fragmented and channeled into so many different sewers along the way if it wasn't for this one remaining ravine we would have lost track of it entirely. And there is a ghost of a railroad, the Belt Line Railway, whose corridor still runs above this drain and now provides a multi-use path up through Forest Hill and west to the former Borough of York.

The Belt Line Railway was conceived at the end of the 1880s, as a prolonged real estate boom drove speculative investment beyond the edges of the then-City of Toronto. Unlike competing radial railways, which were designed as spokes with the city at their centre, the Belt Line looped through the undeveloped lands around the city, before driving into downtown through the Don Valley in the east and via the Grand Trunk Railway corridors in the west. The construction of the northeastern loop of the Belt Line obliterated much of the Yellow Creek, as its tracks and stations were built in the creek's ravine to maximize the availability of the surrounding lands for residential development.

Despite enthusiastic planning, the prolonged depression of 1893 brought an end to the real estate boom, and the lands the railway accessed remained largely undeveloped for years afterwards. Commuter trains ran on the Belt Line for just two years, before the service was shuttered in 1894. The track was rebuilt in 1910 to serve as a freight line, and remained in use by the CNR into the 1970s. Today's multi-use trail was only installed after the city purchased the eastern part of the corridor in 1990.

The Belt Line sewer appears to have been constructed with the railway c. 1890-1892. West of Yonge Street, it is primarily a horseshoe-shaped concrete arch, growing from 1300mm to 1800mm as it runs southeast, and for the most part it is buried very shallowly just beneath the railway bed. In the vicinity of Yonge Street, the horseshoe-shape is overtaken by a flat-sided, A-shaped arch that may have been built either earlier or later than the rest of the original sewer. Downstream of this A-shaped conduit, the drain passes into a much-older arched chamber built of rough stones that must be a much older culvert built to channel the creek beneath Yonge Street. From here, more modern round concrete pipe was later installed to remove the 'nuisance' of the creek from the manicured perfection of Mount Pleasant Cemetery. While much newer than the arched part of the sewer, most of the access shafts in the cemetery have been made unusable by heavy deposits of flow stone and slime. The fairly gross flows of material that now coat the rungs of these access ladders are easy to imagine as having originated in the burial plots that surround this stretch of the sewer.

While the main conduit of the Belt Line sewer runs directly beneath the rail corridor from north of Eglinton southeast to Yonge Street, since its initial construction a fairly complicated network of additional drains and chambers have been connected to it. As a whole system, the lines that converge in the Belt Line sewer now serve to provide storm drainage for most of Forest Hill, with the exception of that corner lying roughly southwest of Old Forest Hill Road. A second, modern RCP runs down from Eglinton Park, through the neighbourhood just west of Yonge Street, passes into the cemetery and first crosses either over or under the RCP of the main line before joining it near the southwest corner of the cemetery. This branch is deep, and would have been tunnel excavated -- as a result it has large access shafts connecting it to the surface. It also contains a number of strange side connections and chambers along its eastern side which may have something to do with condo developments along Yonge between St. Clair and Eglinton.

Near the top of the main conduit beneath the Belt Line, a pair of interconnected storage tanks were built in the 1970s or 1980s beneath the field at Memorial Park in order to prevent overflows from the undersized main sewer here and in the corridor to the southwest from flooding land and basements. These large chambers receive flows from the main sewer during intense rainfall events via an overflow weir and chamber near the intersection of Chaplin Cres. and Roselawn Avenue. Overflow water that reaches the Memorial Park tanks is returned slowly to the Belt Line sewer by way of a small-diameter connection at the south/east end of the tanks. Beyond some very accomplished concrete formwork in its construction, this chamber is also notable for a fascinating custom-built flow meter installed by the city's works staff at some point and hopefully still monitored. This ingenious meter is entirely mechanical: a plastic tube contains a series of one-way metal gates and a tennis ball; as water in the chamber rises, it lifts the tennis ball through the gates, depositing it in the highest chamber of the tube reached by the water and leaving it there until the meter is reset by hand. We've seen similar devices in a couple of other Toronto drains, but this one is probably the best-looking of the ones we've found.

  1. 1. Margaret Atwood. 1989. Cat's Eye. New York: Doubleday Dell, pg. 208.
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Michael Cook is available to speak to your organization about infrastructure history, lost creeks, current conditions, and opportunities for change in our management of and communication about urban watersheds, and to work with teams proposing or implementing such change. Get in touch.