The corrugated metal section of this drain is coated with a thick, rubbery tar, apparently intended to increase the lifespan of what is by now a notoriously bad material for building large sewers.

Westview Greenbelt

North York Storm Trunk Sewer

Water/Sewershed:
Parsons Creek
Black Creek tributary
Amesbury / Glen Park / Lawrence Heights storm sewers

Construction Details:
RCP and CMP (up to 3500mm). Contains a series of concrete stairs and long concrete ramps with corrugated metal ceilings.

Further Reading:
8 Southern Ontario creeks we could start daylighting tomorrow

The North York Storm Trunk Sewer is an extensive sewer built by Metro in the late 1950s and early 1960s to relieve combined sewers in the southwest corner of North York and to drain a portion of the Spadina Expressway. It had the effect of redirecting a large portion of stormwater from this area, which would have previously flowed southeast into Don River tributary creeks, into the Black Creek and Humber River system. Its construction was contemplated as early as 1949.1 Fed by smaller lines running beneath the Allen Road and Lawrence Manor, it drives almost due west to Keele Street, where it enters a twisting ravine now known as the 'Westview Greenbelt'. This ravine once extended at least as far east as the CNR tracks near Caledonia Road, and was dug by a now forgotten creek that has been incorporated into the drain. The water now emerges from a large outfall at the edge of the Black Creek Valley.

This storm trunk sewer contains a series of fascinating features. Heading upstream from the outfall, you first pass through a stretch of rough-walled round concrete pipe. It has something of the smell and feel of a natural cave, and its first few metres have been painted entirely black in an effort perhaps to scare kids away from exploring it. Beyond this section of RCP, we reach a corrugated metal pipe (CMP) that carries the drain through the turns and slopes of the ravine above. Unusually, this large-diameter CMP was coated with a thick layer of rubbery tar to protect it from rust, erosion and premature failure; unsurprisingly large sections of this tar by now been torn away and the metal beneath it has severely eroded in several locations.

Beyond the corrugated metal, the drain settles down a bit, although the stretch from Keele to Dufferin is punctuated by a series of long slides and a few sets of concrete stairs with railings. We also once found large accumulations of detergent bubbles at various points along the trunk sewer, but that experience has yet to be repeated.

  1. 1. Gore & Storrie. 1949. Toronto and York Planning Board Report on Water Supply and Sewage Disposal for the City of Toronto and Related Areas. Toronto, September 1949.
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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.