Port Mann Water Supply Tunnel

1 kilometre-long tunnel,
the first bored under the Fraser River

3.5 metre-diameter,
segmentally lined tunnel for excavation support

2.1 metre-diameter
steel pipeline delivers potable water

2 entry and exit shafts,
69 metres and 81 metres deep, respectively

Challenges

The new river crossing supports the projected increase in the area's population and replaces existing cast iron pipelines, which were vulnerable to damage by riverbed scour and earthquakes.
The project included construction of a one-kilometre-long tunnel, interfacing with two entry and exit shafts, one 69-metres deep and one 81-metres deep. Slurry walls were constructed for temporary shaft excavation support and an earth-pressure-balance tunnel boring machine was used for the 3.5-metre-diameter tunnel.
Potable water moves through a new 2.1-metre-diameter steel pipeline in the shafts and tunnel, conforming to CSA Z662 standards.
With the region's complex, glacial soils, shaft-sinking and tunneling operations faced challenging ground conditions.

Solutions

Provided construction management, administration, and inspection services to Metro Vancouver.
Managed the implementation of a tunnel-intervention contingency framework, which enabled effective risk-sharing between contractor and owner.
Undertook a pre-bid review of the geotechnical baseline report to improve risk management.
Reviewed and negotiated several complex, differing, site condition claims on behalf of the owner.
Provided the owner with a world-class team of tunneling professionals, based locally.

Highlights

Completed under budget
First bored tunnel under the Fraser River; tunneling encountered the highest earth pressures seen in Canada to date
First of several seismically resistant marine crossings to be completed in the Greater Vancouver Water District system over the next few years
2016 Canadian Innovation Project of the Year, Tunnelling Association of Canada
2017 Award of Excellence, Association of Consulting Engineering Companies, British Columbia
2017 Schreyer Award, Association of Consulting Engineering Companies, Canada

For those of you that don’t yet know, the Port Mann Water Supply Tunnel went into service yesterday and is now delivering potable water to the municipalities south of the Fraser River. I want to thank all of you and your staff for helping the Greater Vancouver Water District achieve this major infrastructure milestone. This project is quite remarkable; we set some very challenging design requirements under difficult ground conditions and through our collective efforts were able to stretch our abilities and overcome those challenges.

Frank Huber | Director Major Projects, Metro Vancouver Water Services

Project Numbers

Capital cost of CAD 170 million
1 km of 3.5m diameter earth-pressure balance TBM-driven tunnel under Fraser River
Shafts of 69 m and 81 m depth (Surrey and Coquitlam), BC
Steel pipeline 2.1m diameter, conforming to CSA Z662.