How a 100-Foot Sanitary Sewer Forcemain Is Installed Underground: HDPE Fusion in Action

Forcemain Upgrade Design-Build Project – City of Chilliwack

For nearby residents and commuters, the project offers an unusual glimpse into the scale and complexity of underground infrastructure work — and a rare chance to watch a 100-foot pipeline disappear beneath the streets, one massive section at a time.

Sandpiper is currently delivering a $5.2 million design-build sanitary forcemain upgrade for the City of Chilliwack. The project includes the installation of approximately 970 metres of new 900 mm diameter forcemain between Wolfe Road and Hodgins Avenue.

What makes the installation especially eye-catching is the sheer scale of the pipe sections being lowered into the ground. Each HDPE pipe arrives onsite in 15-metre (50-foot) lengths. Crews then fuse two lengths together above ground, creating massive 30-metre (100-foot) sections before installation.

"These are some of the biggest pipe sections most people will ever see moving through a neighbourhood," says Jordan Knickel, Sandpiper's Project Foreman. "People stop all the time to watch us lower them into the trench."

The 30-metre length is the maximum the crew can safely install at one time due to the number of underground utilities crossing through the corridor.

To create the continuous pipeline, Sandpiper uses a specialized onsite fusion machine that joins HDPE pipes and fittings into a single seamless system.

"We're doing above-ground fuses with our pipe fusion machine onsite by joining HDPE pipes and fittings together into a single, seamless pipeline," explains Jordan. "Basically, heat and pressure melt the pipe ends together, creating a leak-proof joint."

While the installation may appear smooth from the surface, conditions underground have presented significant challenges for crews.

"At the bottom of the excavation, we're right at groundwater level," Jordan says. "We're dealing with unstable ground and cave-ins deep in the trench, so trench boxes are required the entire way."

Crews are excavating and working entirely within protective trench boxes to maintain safety while navigating the difficult soil conditions.

The project also involved maintaining the existing wet well and flow meter locations while safely decommissioning the original 600 mm asbestos cement forcemain connected to Sanitary Pump Station No. 9.

Additional work includes comprehensive site investigations, flushing, testing, and commissioning of the new forcemain system, along with structural installations, environmental protection measures, tracer wire installation, and all related work necessary to ensure long-term reliability.

The removal of existing valves and fittings at 45161 Wolfe Road associated with the decommissioned pump station has also been completed.

All piping layouts, materials, valve types, and associated appurtenances were designed and constructed in accordance with City standards. Final restoration will include a minimum of one full lane width of trench paving.

For nearby residents and commuters, the project offers an unusual glimpse into the scale and complexity of underground infrastructure work — and a rare chance to watch a 100-foot pipeline disappear beneath the streets, one massive section at a time.

West End Connections

• Tie-in to the existing 750 mm concrete pipe at the Dyke Road and Wolfe Road intersection
• Installation of a 300 mm bypass connection near Dyke Road, adjacent to the existing 300 mm HDPE forcemain
• Provision of a 600 mm pipe stub with valves and fittings to accommodate a future bypass to the existing 750 mm SPS No. 10 forcemain

East End Connections

• Installation of a new 750 mm / 900 mm forcemain connection downstream of the 400 mm MAC flowmeter at the designated meter chamber
• Construction of a flush-out chamber near SPS No. 1 off Hodgins Avenue, including 600 mm flushing pipes, valves, and fittings, along with a 600 mm stub for future connection to the existing 600 mm asbestos cement forcemain
• Installation of a 600 mm tee, valves, and fittings to allow for a future SPS No. 2 forcemain connection from Sunset Drive

This project enhances system capacity, reliability, and flexibility while accommodating future expansion of the City's wastewater network.