Project Outline

The Western Beaches Tunnel was designed to reduce the discharge of untreated storm water and sewage into Lake Ontario. The tunnel was designed by consulting engineers Acres in a design-build team with the construction firm McNally Frontier Kemper. The structure is a four-kilometre long tunnel that stores wastewater for at least 10 hours. The storage time allows solids such as dirt, leaves and pollutants that are contained in storm water and sewage to settle to the bottom of the tunnel, from where they can then be pumped to the Ashbridges Bay Treatment plant for treatment.

Liquids in the tank are treated through ultraviolet disinfection to reduce the bacteria and then released into the lake. The $52 million project included a new pump station at Strachan Avenue.

The Western Beaches was 1998 to 2002.

Shaft Descriptions

3x 30 Meter Diameter, 45m deep shafts
4 km long tunnel
Shale tunnel – Main beam Robbins TBM