The DR&CW project will keep combined sewer overflows out of Lower Don River, Taylor-Massey Creek and Inner Harbour by:

  • capturing it within the tunnel system.
  • transporting it for treatment.
  • storing it during extreme rainstorms until system capacity is restored and the water can be transported for treatment.

The project will be done in stages. The first stage is the Coxwell Bypass Tunnel, a 10.5 km long, 6.3 m diameter tunnel. The complete DR&CW Tunnel System will include:

  • a 22 km tunnel system consisting of three integrated tunnels:
    1. Coxwell Bypass Tunnel (stage one)
    2. Taylor Massey-Creek Tunnel
    3. Inner Harbour Tunnel
  • 12 wet weather flow storage shafts along the tunnels.
  • 27 connection points to the tunnels for stormwater and combined sewer overflow.
  • seven off-line storage tanks.
  • Real-Time Control (RTC) to regulate flows in the City’s sewer system.


Construction of phase one of the Coxwell Bypass Tunnel runs from 2018 to 2024. Timing of the future stages is dependent on funding, regulatory approvals, and other considerations.

View construction notification for all current projects.

The new integrated pumping station will move raw sewage from underground sewers into the treatment plant. The plant will:

  • receive and pump the additional flows that come from the Don River and Central Waterfront Tunnel System.
  • provide additional capacity for population growth.
  • replace the current two pumping stations, one of which has been in operation since 1919 and the other since the 1970s.
  • be constructed on the property south of Lake Shore Boulevard East (both of the old pumping stations are north of Lake Shore Boulevard East in Main Sewage Treatment Playground).


Construction will span 2018 to 2026.

View construction notification for all current projects.

The Ashbridges Bay Landform Project is a joint initiative between the City and Toronto and Region Conservation Authority (TRCA).

The project will:

  • provide erosion and sediment control to improve passage for boats, eliminating the need for regular dredging in the Coatsworth Cut area of Ashbridges Bay.
  • be built south of the Ashbridges Bay Wastewater Treatment Plant and will be the site of the high-rate treatment facility and a stormwater treatment wetland.

The high-rate treatment facility is designed specifically to provide treatment of CSOs intercepted by the new tunnel system.


Construction (Landform project) will span 2019 to 2025.

The UV Disinfection Wastewater Treatment System will:

  • provide reliable disinfection as part of the full wastewater treatment process without the use of chemicals.
  • replace the current chlorine disinfection system.
  • use next-generation UV lamp technology which is more energy efficient and requires less space than conventional UV lamps.
  • include sodium hypochlorite disinfection and dechlorination for excessive flows to the plant caused by extreme rainstorms.


Construction will span 2018 to 2022.

View construction notification for all current projects.

The wastewater treatment plant outfall is the point at which the effluent (the fully treated wastewater) is discharged back into Lake Ontario.

A new outfall is being built to improve capacity and better convey the effluent from the Ashbridges Bay  Treatment Plant (ABTP) into Lake Ontario.

The outfall includes:

  • a 14 m diameter shaft, approximately 85 m deep
  • a 3.5 km long, 7 m diameter tunnel, mined through rock beneath the lakebed
  • 50 risers to disperse treated and disinfected effluent into Lake Ontario

Tunnelling operations will be supported from an onshore shaft.

The risers will be drilled from in-water barges.

Timing and Budget

Construction will span 2018 to 2024.

View construction notification for all current projects.


While building the Coxwell Bypass Tunnel and the Integrated Pumping Station over the next 10 years there will be activity at the Main Sewage Treatment Playground. This park runs south from Eastern Avenue to Lake Shore Boulevard East; west of Coxwell Avenue. The activities here will include:

  • Space along the west end of Main Sewage Treatment Playground at the current location of the Tubs & Gee Gage Rugby Field will be used for construction activities as well as storing construction materials, equipment, and trailers.
  • The eastern half of the existing parking lot located at the northwest end of the park will be used for construction administration office trailers.


  • The Tubs and Gee Gage Rugby Field will be relocated within the park, north of Ashbridges Skateboard Park.
  • A new parking lot with 55 parking spaces, bike racks and lighting system, will be constructed on the east side of the park.

View construction notification for all current projects.