Garrison Creek Sewer
Garrison Creek Sewershed
Year of Construction:
Brick pipes ranging from 1650-1950mm in the old sewer, and up to 2775mm in the new sewer. Upstream of Bloor Street, concrete arch tunnel about 1800mm in height. Old sewer built 1884-1886 by A.W. Godson and Alan J. Browne for the City of Toronto. New sewer probably built 1910-1913 as part of the construction of the interceptor system.
The Garrison Sewer. It's the pulsing heart beneath Toronto's west end, lamented when not completely forgotten by those who live and play above, "a secret stream with hidden histories." 1 And, beginning in 2008, after years of wondering about it, I finally stepped into the creek.
There are two distinct pipes that together bear the title "Garrison Creek Sewer." The first, or "old" sewer, buried the creek in 1884-1885, initially between College Street and the old lakeshore, and soon as far north as Bloor Street. Parts of this first sewer still carry the creek and the area's sewage, while other parts are semi-abandoned or have been repurposed as an overflow sewer. The second, "new" Garrison sewer was installed c. 1910-1912 as part of a wider programme of sewer improvements tied in with the construction of the city's first interceptor system, and the main portion of this conduit runs between Bloor Street and Trinity Bellwoods. Around this same time or shortly thereafter, additional sewers north of Bloor buried the final section of aboveground creek in the Christie Pits.
Beneath Christie Pits, Garrison Creek flows in a trench down the middle of a small, arched concrete conduit located just below the floor of the park (pic). Approaching Bloor Street, the tunnel was modified in the 1960s to facilitate the construction of the Bloor-Danforth subway line and the Toronto District School Board's Bickford Centre across the street. One slide and junction, now clad in concrete, still roughly resembles the brick chamber depicted in an archival photograph, but much of the workings beneath Bloor Street look much newer. Once beneath Bickford Park, a flooded concrete chamber (pic) marks both the return of the 1912 sewer and an access point to the northern terminus of the old sewer. A large opening in the east wall of the chamber leads down a slanted pipe into the small, yellow brick pipe (pic) that once carried the creek in this area. This pipe is now mostly empty except when the more modern structures alongside it reach capacity and overflow down this side connection -- the old, yellow sewer is intersected by the 1912 sewer further south at the bottom of Harbord Park. Retaining this connection with the old sewer offers the system some additional capacity, though it is difficult to guess whether this made a real difference to drainage and overflows in the area.
That first connection chamber is flooded because beyond it an organic weir has developed around what may have been a chain installed across the three-meter pipe. Decades of deposited sanitary products, rope and other fouling materials have produced a dam across this point that holds back a pond of sewage nearly waist deep. Beyond this, a more normal quantity of sewage flows through the conduit as it runs south towards Harbord and then College Street.
Beneath Harbord Street, a buried bridge once spanned the ravine before the city chose to bury it in 1930. When the new Garrison sewer was installed in 1912, the space available between the piers of its central arch would have been quite limited -- the old sewer already ran through this gap -- and as a result the new conduit narrows and elongates into a tall, lozenge shaped passage with concrete sidewalls (pic) for about fifty feet where it must pass beneath the bridge. Sewage flows quickly through this structure, and photographs here were touch and go as we had to work to avoid splashing our cameras, tipping our tripods as we worked our way around them to light each image, or having them washed away in the fast flow.
Below Harbord the sewer calms down even though the land above slopes more rapidly down towards College Street. In front of Montrose Jr. Public School, where Beatrice Street turns west to meet Montrose Avenue, the 1912 sewer intersects the path of the old Garrison sewer (pic). As both sewers were built to the grade of the creek they entombed, they meet here again at similar depths. On the east side, the old sewer ends half flooded, its mouth blocked by the lower structure of the new sewer (to prevent dryweather flow from washing back up into the old sewer). We could remember getting to a point where the old sewer was flooded when we explored it from Bickford Park, and were surprised to find more than a year later that we weren't very far away from rejoining the new sewer. On the other side of the new sewer, a concrete wall covers the lower half of the opening to the downstream part of the old sewer, which is dry and empty save for a few hardy rats. From here, the old sewer runs south down Crawford Street at least as far as College Street. We're not sure what happens to it there, but another fragment ultimately terminates at the overflow chamber for the Garrison Relief Sewer just north of Dundas Street.
At College Street, the new sewer makes a series of turns (pic) that take it behind the Metro grocery store at Crawford and College, and then south towards Bellwoods. We had to turn around at a very perilous chamber that houses a control gate for the Mid-Toronto Interceptor -- the modern square chamber doesn't give any outward sign that it is in fact much deeper than the sewer on either side of it, and downward currents make it to drown here if you were misfortunate enough to misread the situation and step into the depths. This is a structure that should be chained or tell-taled to warn of the danger, but for whatever reason it hasn't been.
South of here, my understanding of the system gets sketchier. It could be that the diversion for the Mid-Toronto Interceptor is actually in this small chamber, and we just missed it. Or it could be south of the overflow chamber in Roxton Parkette that serves the Relief Sewer. Either way, in 2009-2010 it appeared that most or all of the flow was not being intercepted by the MTI, but instead was flowing south, through Trinity-Bellwoods Park, to be intercepted by the High-Level Interceptor. Either way, it appears that the 1912 sewer terminates at the overflow chamber for the Relief, and that flow from there passes into the (smaller) 1885 sewer for its journey through Trinity. Past the High-Level interception chamber, that old sewer, in all its yellow-brick glory, continues right to the old lakeshore -- that section is documented on this website as the Garrison Creek Sewer (overflow).
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.