The Fairbank Silverthorn Storm Trunk Sewer System project is being implemented to resolve chronic basement flooding in the Fairbank Silverthorn neighborhood through future sewer separation connected to the Fairbank Silverthorn conveyance and in-line storage tunnel with outfall to Black Creek.
The main tunnel is 2,400 m of 4,000 mm diameter tunnel up to 50 m deep in soft ground and 525 m of 1,800 mm diameter sewer to the new outfall. The project also includes microtunnel sections of the local collector sewers, including 400 m of 1,800 mm diameter and 1,000 m of 1,500 mm diameter sewers. The local collector sewers are connected to the main tunnel via 4 shafts with vortex drop structures and adit connection, ranging in depth from 14 m to 43 m.
All the tunnels, including microtunnels, are expected to be in soft ground conditions along the entire alignment consisting predominantly of silty clay glacial till with stratified glaciolacustrine silt, clay and sand deposits. The engineering firm Jacobs has been retained for design and construction services for the project. Construction is scheduled to begin in 2021, with prequalification beginning in spring 2020. Two additional contracts for approximately 10 km of collector sewers will follow in 2021. The estimated total project cost, including collector sewers contracts, is $225 million (CAD).
Project owner: City of Toronto; Design Engineer(s): Jacobs.
For more information, visit the project website.