In the main overflow tunnel fo the East Toronto and Midway sewer complex, beneath Coxwell Avenue.

Beneath Toronto's East End: The East Toronto and Midway Sewer System

Michael Cook

For a long time, the sewers in Toronto's west end were unchallenged in my mind as both the most fascinating old sewer system in the city, and the one most in need of exploration. However, as a result of my colleagues' dogged determination, there is some serious competition on the eastern horizon: the East Toronto and Midway sewers, a network of pipes and conduits as complicated as the Garrison system but with fewer impassable diversions into the interceptor system and confined, hazardous environments.

Admittedly, we did have to boat across one diversion (please do not try this), and sections of these eastern sewers are significantly harder to stomach than their western cousins. In between these trials though, we discovered a compelling system that reveals a lot about the neighbourhoods above it and the history of how the east end came to be incorporated into Toronto.

Origins of a Sewershed

The history of sewer development in the area of the old City of Toronto east of the Don River is a story of expansion and contraction: Expansion of the central city, which required additional land not only for residential and industrial developments but also for critical civic infrastructure like sewage and water treatment plants; and contraction of the area's natural watershed, especially in the area south of the old Iroquois shoreline. In this respect, it shares a very similar geography and history with the old town of York and early City of Toronto, whose flat, marshy, muddy landscape of water was dispensed with as quickly, cheaply and completely as possible. However these things happened in the east end far later, making it easier to tell the story and explain the buried system that was installed to replace the surface watershed.

Up until 1908, Toronto's city limit ended just east of Greenwood Ave., on the western shoulder of the Ashbridges Creek ravine, save for a narrow strip the city had already claimed along the lakeshore as far as Balmy Beach. The area east of Woodbine Ave., spurred by the Grand Trunk Railway's freight yard north of Gerrard St., was beginning to develop into an industrial community and suburb then known as East Toronto, while the land in between Toronto and East Toronto had only been sparsely settled (the largest community the unincorporated Village of Norway) and was known somewhat appropriately as Midway. However, though development came relatively late, residential pressures quickly had an impact on the area's delicate watershed.

A dredging platform at work 'improving' Ashbridges Bay in the 1890s. City of Toronto Archives, Series 376, Sub-Series 4, Item 47


Through the 1880s, Ashbridges Bay was a much larger body of water than it is today. Water in the bay was shallow, heavily vegetated and slow-moving, a fertile marsh stretching as far north as what is now Queen St. E. But modern cities have been particularly poor at co-existing with wetlands — they are neither dry enough to have been valued until recently as natural leisure spaces, nor wet enough to serve as waterways for navigation or the successful conveyance of sewage and industrial wastes. Instead, wetlands were spaces to be 'improved', either through infill to create buildable land, or dredging to create navigable canals and to solve the 'nuisance' of their stagnant pollution. Being such a large marsh on the city's immediate doorway, Ashbridges afforded Toronto the opportunity to think big, and a variety of development plans were proposed before the Toronto Harbour Commission eventually moved ahead with infill of the western area, which became the Port Lands. From 1909 on, much of the remaining eastern part of the bay would be reclaimed for the ever-expanding Main Sewage Disposal Works (now known as the Ashbridges Bay Treatment Plant).

The low lands below the Iroquois shoreline (the elevation change takes place between the Danforth and Gerrard/Kingston Rd.) harboured only small surface creeks and shallow groundwater. Streams flowed from Midway (Ashbridges Creek) and East Toronto (Smalls Creek and Tomlin's Creek) into Ashbridges Bay, but these along with the area's shallow wells were quickly disrupted and used up by intensifying residential development. With only a marginal tax base, these eastern communities began to urgently require the assistance of the City of Toronto to modernize their water and sewer services.

The east end's growing water crisis simply joined the City of Toronto's existing crisis, which by 1900 had already been in progress for a good three or four decades. While small sewers draining from the core into the harbour had been built throughout the 19th century, and the Garrison, Taddle and other major creeks converted to sewers in the 1880s, the city had yet to successfully implement a scheme to do anything with this sewage save to convey it to the enclosed, slow-moving harbour. In 1886, 1887 and 1907, ratepayers rejected plans to build a system of intercepting sewers ("the trunk sewer system") that they saw as too expensive, but which would have placed an outfall and treatment plant somewhere east of the city's limit, well clear of the harbour and the city's existing drinking water intake and filtration plant on Toronto Island. 1

A plan for a trunk sewer system was finally approved by taxpayers in 1908, after another urgent warning from the city's Medical Officer of Health. The resulting large investment in modernizing and expanding the city's sewer infrastructure, almost all of which was physically oriented towards conveying sewage to a treatment plant site on that finger of city-owned land north of Ashbridges Bay, would have made annexing the surrounding lands a more appealing prospect. In 1908-1909, construction began on the intercepting sewer network and the treatment plant and outfall at Ashbridges, and the city annexed Midway and East Toronto. Their water and sewage deficiencies simply became another target for the sewer expansion underway in the trunk sewer system program, while that system of interception and treatment now provided the city with the capacity to use sewer servicing to encourage building on undeveloped land,2 which it promptly did for Midway. In 1913-1915 the Midway and East Toronto sewers were built to convey wastewater to the new Main Sewage Disposal Works at Coxwell and Eastern Ave., and an overflow sewer built from both sewers to Ashbridges Bay to convey the storm surge, untreated, into the lake.

Just south of Dundas Avenue, junction chamber for the East Toronto and Midway overflow sewers. (East Toronto and Midway Overflow Sewer)

The East Toronto and Midway Sewers

The system that was put in place for East Toronto and Midway comprises two wholly separate combined sewers, with the Midway sewer running north-south just east of Greenwood Ave. on roughly the former alignment of the lost Ashbridges Creek, and the East Toronto sewer begins as separate arms coming down Woodbine and Main St. before turning west beneath the curving, western end of the Kingston Road. Each is intercepted north of Dundas Street -- the Midway sewer is diverted into both the High-Level Interceptor and the Mid-Toronto Interceptor (added in the 1970s), while the sewer for East Toronto is sent along with some other local sewers into a small pipe that leads directly to the Main Treatment Plant. The treatment plant has now been moved to the west side of Ashbridges Bay, south of Lakeshore Blvd, but flow from these sewers still passes through the interceptors to the old Wet Well at Eastern Ave., from which it is pumped south to the contemporary Ashbridges treatment facility.

These diversion structures were never intended to be sufficient to handle the wet-weather loads on these combined sewers, and so when it rains they overflow into a pair of tunnels that join at Dundas and Coxwell to extend these sewers to Ashbridges Bay. This overflow system is best known as the East Toronto and Midway Overflow Sewer, though photos at the Toronto Archives refer to it as the 'East Toronto and Midway Storm Sewer'. A large concrete arch with multiple junctions, this is the section of the sewer that initially sparked our interest in the system.

Downstream end of the original overflow sewer. The concrete ducts beyond appear to have been added later. (East Toronto and Midway Overflow Sewer)

The junctions at the north and south end of the Coxwell stretch of the overflow tunnel appear almost identical to how they were when they were photographed by Public Works in the 1940s, the images that have found their way to the Toronto Archives. My colleague Jon Muldoon prepared two 'then and now' photographs (1 2) which recreate the lighting and framing of the originals from the archives. The north junction (where the two arms of the overflow join) has been modified with the addition, just inside the East Toronto arm, of an additional chamber and a connected small round concrete storm sewer.

While the overflow sewer was built entirely of concrete, the combined sewers include brick sections. The Midway sewer starts off as a balloon-shaped brick pipe beneath the area north of Monarch Park, before expanding to a round brick pipe when it nears Gerrard. The part of the East Toronto sewer that we have seen (it quickly shrinks to an uncomfortable height) is a concrete arch with a brick floor that curves down to form a central channel with 'sidewalks' on either side. Maps appear to indicate that it retains this general form through much of its length, though the portions under Main St. and the Danforth are likely round or balloon-shaped brick pipes.

Of special note is the 'L'-shaped diversion chamber added to the Midway sewer when the Mid-Toronto Interceptor (MTI) was built in the 1970s. This large chamber includes catwalks and a vertical shaft used to lower by crane the metal stop-logs that serve as the diversion weir. Diverted sewage forms a deep pool behind that weir before passing east into a second rectangular part of the chamber (the foot of the 'L') from which it drops through a small hole into the MTI. The brick floor in this chamber is modern. The manufacturer's stamp on each brick identifies them as having been fired by Domtar, once an industrial chemical and materials empire before it shed all those other holdings in the 1980s to focus on paper.

No structure has been provided to allow direct access across the deep, potentially dangerous pool of sewage behind the weir, so as noted we were forced to raft across it. Jon's action shot captures the whole endeavour quite well. (Again, please do not try this). Paddling upstream against the concentrated flow emerging from the round pipe was particularly difficult, a task made worse by the narrow clearance provided by the curving walls.

Downstream of the MTI diversion, the remaining stretch of what was originally the Midway combined sewer (the part from the MTI down to the older diversion trough to the High-Level Interceptor) is a mess. With no regular flow to convey the household sewage falling into the pipe from connections at head-level, the waste simply sits and rots on the floor until rain causes an overflow from the chamber upstream. This is to say nothing of the fraught experience of simply walking through this Midway sewer (and its counterpart further east) — head-level household connections mean that at any moment the pipe next to you could start spewing out the contents of a well-meaning toilet flush.

If my attempt at describing this network of sewers and diversions in overview here proves confusing, I have also posted individual sewerage articles about the Midway Combined Sewer, the East Toronto combined sewer, and the East Toronto and Midway Overflow Sewer. See the map below as well.

Acknowledgements: It would have been impossible to explore the East Toronto and Midway sewers and to tell this story without the work of my colleagues, Jon and Bryan. Jon has recently departed the city for the west coast, but the east end was his home for years and the dream of a sewer system like this one was a goal he clung to despite my skepticism. Once we determined (thanks to the archival photographs linked above) that this system was indeed worth pursuing, Jon and Bryan were able to take a mapping lead I'd generated and ran with it. Their hard work pushing the tight, vertical, messy northern part of the Midway Sewer eventually cracked the whole system, providing access to the most complicated and compelling single-visit network of sewers yet explored in Toronto. The effort on East Toronto and Midway was all theirs, and hopefully I've done it justice in this write-up.

  1. 1. Catherine Brace. 1993. One Hundred and Twenty Years of Sewerage: The Provision of Sewers in Toronto 1793-1913. University of Toronto.
  2. 2. Brace, 159.
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