North of Gerrard, where the Midway Combined Sewer takes on its characteristic balloon-shaped form.

Midway Combined Sewer

East Toronto and Midway Sewershed
Ashbridges Creek

Year of Construction:

Construction Details:
Round and balloon-shaped brick pipes.

Further Reading:
The East Toronto and Midway Sewer System

The construction of the Midway Combined Sewer in 1913-1915 accompanied a variety of sewer improvements throughout the rest of the City of Toronto, including the installation of the city's first interceptor system. In dry weather, this system fed sewage from throughout the city to a new treatment plant north of Ashbridges Bay, the Main Sewage Disposal Works.

The areas north (Midway) and northeast (Norway Village and East Toronto) of Ashbridges had only recently been annexed by the growing city, and urgently required sewer servicing. The Midway sewer, along with the East Toronto Sewer with which it shares an overflow, accomplished this task and little more -- the interception structures originally provided for these sewers are very small and easily overwhelmed in wet weather. It appears to largely match the former course of Ashbridges Creek (which may have already been straightened) which flowed just east of Greenwood Avenue to an outlet in the old western part of Ashbridges Bay that is now filled and occupied by the contemporary Ashbridges Bay Sewage Treatment Plant.

The construction of the Mid-Toronto Interceptor in the 1970s provided additional capacity for this system. The Midway sewer is now diverted into the MTI through a modern chamber located just south of Gerrard. While this provides more robust protection against overflows in light rain events from the upper part of the system, it leaves the next block of the sewer — down Hiawatha Road to Dundas St. E. — without significant conveyance. This means that household sewage simply drops onto the dry floor of the round brick pipe, with no consistent flow to carry it away down to Dundas where the older diversion to the High Level Interceptor still exists. It's not a problem for the wider environment (although one has to assume that overflows through this system to Ashbridges still occur frequently), but it certainly makes passage through this stretch of the overflow sewer a disgusting proposition.

North of Gerrard, the sewer is a much-smaller balloon-shaped pipe. It runs beneath Monarch Park and down a series of drop chambers that carry the sewer down the topology of the old Lake Iroquois shoreline.

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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.