A unique application of Diaphragm Wall to facilitate the excavation of New River Channel on The Port Lands Flood Protection and Enabling Infrastructure Project in Toronto, Ontario-Paper

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The Port Lands Flood Protection and Enabling Infrastructure Project is creating a new Don River channel in Toronto to reduce flood risk and support waterfront redevelopment. The site’s industrial history has left extensive soil and groundwater contamination, making a reliable hydraulic cutoff essential.<br /><br />At the channel’s western end, a diaphragm-wall plug was designed to keep Lake Ontario water out during excavation and later be removed to connect the new river to the lake. The wall also served as a dock wall, bridge-loading pier, temporary retaining structure, and dam. Its T-shaped panels provided stiffness under changing loads, while milled, overlapping panel joints helped limit water ingress through the wall, including its rock socket.<br /><br />The design-build diaphragm-wall alternative replaced the original secant-pile and tied-back sheet-pile system. It accommodated the curved riverbank, reduced construction joints by more than 90%, cut the schedule by over 50%, and lowered costs by more than 25%, according to the paper. Construction used a Hydromill, with automated inclinometers and cloud-based alerts monitoring wall movement during critical stages.<br /><br />Over its four-year service period, the wall performed reliably through load reversals and seasonal weather. It showed no significant leakage, and measured deflections remained approximately 10–15 mm. The project demonstrates how diaphragm walls can combine structural support and long-term contaminant containment in complex urban flood-protection works.

Keywords

Port Lands Flood Protection

Toronto

Don River channel

diaphragm wall

hydraulic cutoff

Lake Ontario

contaminated soil and groundwater

waterfront redevelopment

Hydromill

flood protection