10/23/2026
The completed Coxwell Bypass Tunnel stretches 10.5 kilometres beneath Toronto, with a 6.3-metre diameter tunnel excavated through shale bedrock approximately 50 metres below the surface.
The project included five major storage shafts and 12 drop shafts, with the tunnel excavated by a tunnel boring machine and lined with precast concrete segments.
Designed to capture and store combined sewer overflows, the tunnel will help protect the Don River and Lake Ontario while strengthening Toronto’s water infrastructure.