City of Calgary completes decade-long Inglewood Sanitary Trunk project to support growing population

The City of Calgary is pleased to announce the completion of the Inglewood Sanitary Trunk (IST) project, a critical infrastructure upgrade ten years in the making that will ensure reliable wastewater service for Calgarians for generations to come.

This multi-phase project, completed in two phases, will enhance Calgary’s wastewater system by increasing capacity and reliability as The City continues to grow. The IST is now fully operational and will serve neighbourhoods in Calgary’s north and inner city through to 2076.

“This is a major milestone for Calgary’s wastewater infrastructure,” says Melanie Gray, Senior Project Engineer. “Our team has focused on building a system that could meet the demands of a growing population, while minimizing impacts to the environment and surrounding communities. I’m incredibly proud to see this project through to completion.”

Phase One, completed in November 2020, involved 3.5 km of microtunnelling and 250m of open cut work to construct a new sanitary trunk line to carry wastewater from the Inner City Trunk in North Inglewood to the Bonnybrook Wastewater Treatment Plant. This work increased capacity and improved service reliability for several inner-city communities.

Phase Two included approximately 600m of microtunnelling beneath the Bow River to create two, 500m tunnels to connect three existing sanitary trunks on the north and south sides of the river. This phase also involved the construction of a 90m tunnel to connect Phase One and Phase Two as well as 20m of open cut work on the north side of the river. This phase was crucial in completing the system loop and enabling the full functionality of the new sanitary trunk.

Both phases of work, equally complex in their own respects, required a total of six tie-ins to existing sanitary lines and moving power, water, sanitary and storm lines along with obtaining four private land agreements to successfully complete this 10-year project.    

Together, the two phases:

• Expand wastewater capacity for a growing population.
• Improve environmental protection by reducing the risk of overflows.
• Increase system resilience and support long-term growth in north Calgary.

“We know projects like this can be disruptive, and we deeply appreciate the community’s cooperation over the past decade,” says Gray. “The end result is a safer, more reliable system that will benefit all Calgarians.”

The completion of this project marks a significant step forward in strengthening Calgary’s core infrastructure. With increased capacity, enhanced system reliability and long-term service to 2076, this project ensures that Calgarians—now and in the future—can rely on safe, sustainable wastewater service.