The City of Calgary has completed the Inglewood Sanitary Trunk (IST) project, a decade-long infrastructure upgrade that will support reliable wastewater service through to 2076, thanks in large part to trenchless construction methods.
Completed in two phases, the IST enhances wastewater capacity and system resilience for Calgary’s north and inner-city communities. A major feature of the project was the extensive use of microtunnelling, a trenchless technology that allowed crews to install infrastructure with minimal disruption to streets, communities, and the environment.
“We built a system that meets the needs of a growing population while reducing impacts to surrounding areas,” said Melanie Gray, Senior Project Engineer.
Phase One, finished in 2020, used 3.5 km of microtunnelling and 250 m of open cut to connect North Inglewood to the Bonnybrook Wastewater Treatment Plant.
Phase Two involved two 500 m tunnels drilled beneath the Bow River, a 90 m connecting tunnel, and only 20 m of open cut. This critical phase completed the system loop and tied into existing infrastructure on both sides of the river.
In total, the project required six tie-ins and multiple utility relocations—made possible with minimal surface impact by using trenchless methods.
“The result is a safer, more reliable system that supports Calgary’s future,” Gray said.
The IST project stands as a successful example of how modern trenchless technologies can deliver major infrastructure upgrades while preserving the urban environment.
Do you have news for the international trenchless industry? Contact journalist Gerald Lynch at gerald.lynch@primecreative.com.au
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