Metro Vancouver | Annacis Island Wastewater Treatment Plant New Outfall System

January 22, 2018

Project status
Permit amendment issued

In January 2024, amendment PER No. 17-093-06 was issued to Metro Vancouver. The amendment approved was a request to extend the expiry date of the approved project permit. The project is located downstream from the Alex Fraser Bridge, on the north side of the Fraser River, in Delta, British Columbia in federal waters managed by the Vancouver Fraser Port Authority.

About the amendment:

Metro Vancouver requested an extension to the approved project permit PER 17-093, which has an expiry date of June 30, 2024, as more time is needed to complete the Project. The scope of works that remain to be completed includes:

- The installation of pre-cast concrete covers over the duckbill valves on the diffuser manifold
- Placement of the backfill material and rip rap over the diffuser manifold
- Removal of the temporary bulkheads that are in the riser pipe assembly

Permit amendments issued

On March 10, 2019, a project permit was issued to Metro Vancouver for the Annacis Island Wastewater Treatment Plant New Outfall System in Delta, British Columbia in federal waters managed by the Vancouver Fraser Port Authority.

The project was approved subject to 46 permit conditions which Metro Vancouver must meet to ensure the project does not result in significant adverse environmental effects.

For more information about the project and construction activities, please go to Metro Vancouver’s website.

Following permit issuance, the port authority has issued various amendments authorizing specific activities to take place outside standard hours to enable the timely completion of the project. These are listed below. For details, please click on the specific amendment hyperlink.

PER No. 17-093-01: between June 16, 2021 and February 28, 2022
PER No. 17-093-02: between April 15 to June 15, 2021
PER No. 17-093-03: between March 1 and June 15, 2022, and between June 16, 2022 and March 31, 2023
PER No. 17-093-04: between March 31 to December 31, 2023
PER No. 17-093-05: between July and December 31, 2023

A record of construction notifications is included under the Resources section of this page.

About the project

Metro Vancouver proposes to construct a new outfall system in the Fraser River as part of upgrades to increase the secondary treatment capacity of the Annacis Island Wastewater Treatment Plant. The new outfall system will replace the existing outfall which was constructed in 1974 and does not provide the required capacity nor meet current design criteria with respect to seismic requirements and dilution requirements. The new outfall system has been designed with an increased capacity to serve current and future treatment plant upgrades, achieve required dilution ratios, and meet seismic criteria. Project components located on lands and waters administered by the port authority include a section of the outfall tunnel, the river riser, and the diffuser manifold.

Proposed project activities and components include:

Construction of a new outfall tunnel with an inside diameter of 4.2 m, utilizing a Tunnel Boring Machine (TBM).
The tunnel will extend from a shaft located on the upland to a river riser shaft located approximately 160 m south of the north bank of the Fraser River. The tunnel will be approximately 30 m below the ground surface on the upland and 15 m below the riverbed
Construction of a river riser, consisting of a vertical steel riser pipe and riser cap within a concrete support structure. The support structure consists of a concrete block, approximately 12 m by 19 m, founded on 24 concrete-filled steel piles with a diameter of 760 mm (30 inches);
Dredging to a depth of approximately 4.5 m below the riverbed to facilitate the installation of two diffuser manifolds, each approximately 130 m long and 2.5 m in diameter;
Placement of bedding material (sand and gravel) at the base of the trench, with subsequent installation of pre-assembled sections of the diffuser manifolds. Once the diffuser manifolds are installed, the trench will be backfilled with river sand and covered with armour rock;
Installation of concrete diffuser protective covers and flexible diffuser ports with check valves; and
Once the new outfall is commissioned, the existing outfall will be rehabilitated by installing new flexible valves on top of the existing 21 steel riser pipes to allow it to serve as an emergency influent bypass.

Construction is expected to take approximately 3 years.

Resources

Contact information

For more information about Metro Vancouver’s proposed project, please go to their website or contact Ken Massé by email or phone at 778.452.2627.

For questions regarding the Project and Environmental Review of the project, or to get in touch with our team, please contact us by email or phone at 604.665.9047.