The Annacis Island Wastewater Treatment Plant’s new outfall project has received both provincial and national recognition in 2025, underscoring its technical achievement, collaborative delivery, and long-term benefits for more than one million residents in British Columbia’s Lower Mainland.
In July, the project earned an Award of Merit in the Municipal and Civil Infrastructure category at the 2025 Association of Consulting Engineering Companies–British Columbia (ACEC-BC) Awards. The honour recognized the collaborative execution and innovative design of the new outfall system, which modernizes aging infrastructure while enhancing capacity, seismic resilience, and environmental performance.
In November, the project was also named 2025 Canadian Project of the Year (Under $300M CAD) by the Tunnelling Association of Canada (TAC), one of the country’s most prestigious awards for underground construction. The national recognition highlights exceptional engineering skill, innovation, and a forward-thinking approach to resilience and environmental protection.
“This is an excellent example of Metro Vancouver’s commitment to building infrastructure that will serve our growing population and withstand challenges like natural disasters and climate change,” said Mike Hurley, Chair of the Metro Vancouver Boards of Directors. “Congratulations to our outstanding team on another excellent engineering achievement delivered on budget.”
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The overall budget for the new outfall system is approximately $356 million.
The Annacis Island plant treats wastewater from a million residents across 14 municipalities. Its original 1970s-era outfall pipe needed to be replaced as it was too small, in poor condition, and not up to modern seismic standards. The new tunnel, completed in August 2025, provides increased capacity, enhanced durability, and seismic resilience while improving effluent dilution in the Fraser River.
Hatch served as construction manager for the project, working alongside CDM Smith Canada as Owner’s Engineer, in partnership with Metro Vancouver and Pomerleau Bessac General Partnership (PBGP).
“This award is a testament to the power of collaboration and innovation,” said Derek Zoldy, regional director for tunnels at Hatch. “We’re proud to have worked alongside CDM Smith Canada and Metro Vancouver to deliver a resilient, future-ready solution that supports the health and sustainability of the Fraser River and the communities it serves.”
Key features of the Annacis Island WWTP New Outfall Project include:
- Increased capacity: Significantly boosting discharge capacity to ensure long-term service reliability.
- Seismic resilience: Two 4.2-metre-diameter conveyance tunnels constructed below liquefaction-prone zones to enhance performance during seismic events.
- Innovative construction: Use of a 5-metre-diameter slurry tunnel boring machine (TBM) to achieve precise tunnelling and installation of precast concrete linings.
- Environmental stewardship: In-river diffuser manifolds designed to promote effective effluent dispersion into the Fraser River while minimizing ecological impacts.
- Future-ready design: An outfall shaft engineered to accommodate a future pump station, addressing sea-level rise and long-term discharge needs.
Tim Langmaid, senior project manager of tunnels at Hatch, said the award reflects the “dedication and ingenuity of the entire project team, who worked together to deliver a solution that will serve the region for generations.”
