New Outfall Pipe

Project Description

Wastewater from the Annacis Island Wastewater Treatment Plant is released into the Fraser River through an outfall pipe once it has been treated. A new outfall location and diffuser system is being installed, which will involve constructing a tunnel approximately one-kilometre long from the plant to the river.

The new outfall location and design will ensure that treated effluent is dispersed over a broad area underwater to maximize dilution and minimize the impact on the environment.

The new pipe is expected to meet the regional growth needs for the next 100 years while ensuring greater seismic resilience and continuous, reliable and safe management of liquid waste.

Project Update


    Schedule Update & Hours of Work

    Diesel impact pile driving within the Fraser River is expected to continue until summer 2021 during the following allowable work hours:

    • Monday to Friday between 7 a.m. and 7 p.m.
    • Saturdays between 9 a.m. and 5 p.m.

    Please note, river conditions and flow rates may impact the work schedule. All work will comply with City of Delta and Vancouver Fraser Port Authority bylaws and permit variances. Construction activities that will not have a significant impact on surrounding communities will resume 24 hours a day, seven days a week, as needed, on April 15, 2021, until February 2022. Anticipated activities will include:

    • Concrete pours
    • Welding
    • Cleaning out piles
    • Vibratory sheet extraction
    • Equipment maintenance

    Noise Impacts & Our Commitment to You

    Metro Vancouver is committed to minimizing the impacts of this work on the surrounding community. To meet that commitment, crews will be using a quieter vibratory hammer to complete the majority of the in-river pile driving work. Heavier impact hammer equipment will only be used as needed during the allowable daytime hours.

Project Activities

  • Tunneling

    The new outfall pipe will be excavated using a tunnel-boring machine. This machine will be launched from the entry shaft near the Annacis Island wastewater treatment plant and progress south to the river riser in the Fraser River (see illustration below).

  • Diffuser System

    The diffuser system will be made up of one long pipe just under the surface of the river bed that will run parallel to the shore. The diffuser system will release treated water through multiple valves attached to the pipe.

    The image below shows the diffuser system that will be built in the river bed, parallel to the shore to avoid the river navigation channel.


Construction is occurring in multiple phases, and is expected to be complete in 2024.

Contact Us

  • Community Liaison


    Monday to Friday from 8:00 a.m. to 4:30 p.m.