2023 Trenchless Technology Project of the Year Rehab Honorable Mention – Port Moody Shoreline Trail Force Main Rehabilitation

The City of Port Moody, British Columbia, required the rehabilitation of 1.5 km of parallel sanitary sewers located in the environmentally and culturally sensitive Shoreline Trail Park at the east end of the Burrard Inlet.

The two sewers run through the park below a paved multiuse pathway and through sections of forested land. Within the alignment the sewers cross five watercourses, two of which are salmon bearing, and through a Great Blue Heron rookery situated above a wetland.

The sewers are located along the north and east shore of the Burrard Inlet in Port Moody. The Shoreline Trail Park is bounded by Burrard Inlet and the Canadian Pacific Rail right of way. These bounds impose both physical and environmental constraints impacting the designs available for rehabilitation of the infrastructure.

The existing force main is a 600-mm diameter DR41 PVC sewer built in 1988 to service the Imperial Oil Co. (Ioco) Lands. The force main along Shoreline Trail is a component of a 5.5-km force main. The 400-mm asbestos cement gravity sewer that runs parallel to the siphon along the Shoreline Trail was installed in 1970.

The City of Port Moody identified several key considerations that the solution must address:

• Environmentally Sensitive Riparian Areas: The sewers cross eight watercourses and riparian areas where with federal restrictions for any work within 30 m of the watercourse outside of the fish window which runs from the beginning of August to the middle of September each year.
• Great Blue Heron Colony: A Great Blue Heron colony adjacent to the path results in construction related restrictions on tree impacts and the timing of construction from Jan. 15 to Sept. 15.
• Pressure Sewers Elevations: Ensure no backflow from the force main into gravity feeder sewers.
• Canadian Pacific Rail Right of Way: Limited work areas and access to site.
• Archeological Material: Existing known archeologically significant sites within or near the project area, and potential new areas.
• Forested Areas: Trees in this area have a high ecological and community value and efforts to limit tree impacts constrained the design in most locations.

Why Project Is Outstanding

The consulting team from Kerr Wood Leidal carried out detailed reviews and assessments of the impacts of various types of construction for the project, and selected CIPP lining as the best solution. General contractor PW Trenchless Construction, teamed with Insituform Technologies, brought a unique combination of construction experience and methods to the project.

A key consideration in planning the project was balancing the requirements of the main work components: force main lining required constructing bypass, excavation of pits, cleaning, setting up installation sites and liner installation; gravity sewer lining required access to manholes adjacent to the paved trail. These tasks required specific equipment that had to share the trail itself, and the limited access resulting from the CP Rail tracks.

All work was planned to meet the owner’s set guidelines, minimizing impact to trees, great blue herons, archaeological conditions, and keeping as much of trail as possible open to the over 200,000 users per year. PW’s excellent experience and local knowledge played a huge role in addressing these issues. A significant factor in smoothing the lining component of the work was their decision to install a full-length bypass, opposed to the suggested method of bypassing in stages, which would have resulted in a longer lining schedule. It also eliminated the need to install temporary and then permanent connections to the existing pumpstation connections to the force main.

Lining PVC host pipes presents unique challenges that the team considered in selecting the lining system. Insituform assessed 3 products for lining and ultimately selected Saertex Type S+XR liner, chosen as least cost, with significant reduction in installation set, and improved cure time compared to epoxy resin systems.

This was to be the first UV cure pressure liner installed in a force main in Canada. Insituform assembled an operations team to ensure successful completion. The local CIPP crew was augmented with Insituform corporate UV and pressure pipe termination fitting expertise, as well as Saertex support onsite. End termination included WEKO end seals at every liner termination location.

Project Owner: City of Port Moody, British Columbia
Engineer: Kerr Wood Leidal
Contractor: PW Trenchless Construction Inc. and Insituform Technologies Ltd.
Manufacturers/Suppliers: Prokasro, Saertex
Value of Trenchless Project (US$): $10.8 million