Enhancing Calgary’s wastewater infrastructure for the future TransCanada Sanitary Trunk

The west side of Calgary along with the Town of Cochrane are currently serviced by the Valley Ridge Sanitary trunk, which transports sewage produced by homes and businesses. As a result of population growth over the last several years, the trunk is nearing its capacity. For this reason, along with the projected population growth in the future, another sanitary trunk is needed which will be The TransCanada Sanitary Trunk (TCST).

This new 8.5 kilometre long sanitary trunk will transport sewage from regional customers such as the Town of Cochrane and other developments along the TransCanada Highway. The infrastructure plans were developed with the community in mind and utilizes methods to reduce the environmental impact during construction. Of the approximate 8.5 kilometres, about 5 kilometres will use the process of microtunnelling while only 3.5 km will be open trench construction. Microtunnelling is a method of installing utilities underground – essentially an underground tunnel – which minimizes environmental, health, and traffic impacts. (See figure 1 for more information).

Project timeline

  • Detailed Design – Q3 2023 to Q4 2024. 
  • Construction – Scheduled for Q2 2025 to Q4 2026.
  • Landscaping – Schedule to be complete by Q3 2027.

Project benefits

  • This project is essential to meet sewage demands in the west part of Calgary given recent population growth and provides adequate capacity for future residential and commercial development to take place.
  • Specific sections of this project work will be completed by microtunnelling, which reduces construction impacts on traffic, parks and green space. This work will primarily near the community of Valley Ridge along with another large section east of Stoney Trail to Sarcee Trail N.W. 
  • Reduces odours in the community of Valley Ridge.

Project maps

Project map
Click image to enlarge.

Construction route access in Valley Ridge

These maps show the proposed routes construction trucks will use during the TransCanada Sanitary Trunk project. The time duration of these routes is still being determined and will be updated on our website.

TransCanada Sanitary Trunk (TCST) construction access route - Valley Ridge Drive & Valley Springs Road NW -
TransCanada Sanitary Trunk (TCST) construction access route - Valley Ridge Drive & Valley Springs Road NW - click to enlarge
TransCanada Sanitary Trunk (TCST) construction access route - Valley Ridge Drive & Valley Ridge Boulevard NW
TransCanada Sanitary Trunk (TCST) construction access route - Valley Ridge Drive & Valley Ridge Boulevard NW - click to enlarge.

Construction route access in the Bowdale area

These maps show the proposed routes construction trucks will use during the TransCanada Sanitary Trunk project. The time duration of these routes is still being determined and will be updated on our website.

TransCanada Sanitary Trunk (TCST) construction access route - Phase 1 - Bowdale Crescent
TransCanada Sanitary Trunk (TCST) construction access route - Phase 1 - Bowdale Crescent - click to enlarge
TransCanada Sanitary Trunk (TCST) construction access route - Phase 2 - Bowdale Crescent
TransCanada Sanitary Trunk (TCST) construction access route - Phase 2 - Bowdale Crescent - click to enlarge.

Construction mitigations

Keeping the sound barrier intact

We will be using microtunnelling to install portions of the sanitary trunk that allows us to keep the sound barrier on 16 Avenue N.W. in place during construction. This is an area just west of Stoney Trail where the tunnelling passes under the sound barrier. Click to enlarge.

Tree protection and repurposing

A small section of trees will be removed and re-purposed along the TransCanada Highways while a large section of mature trees will be protected via a fence and by the process of microtunnelling.
Click to enlarge.


Frequently asked questions (FAQ)

What size will the trunk be?

The trunk will have both 1350 mm and 1500 mm pipe sizes.

Why is this new sanitary trunk needed?

The TransCanada Sanitary Trunk (TCST) is needed because the current trunk that serves the west part of Calgary along with the town of Cochrane is nearing capacity. This project is essential to meet sewage demands in the west part of Calgary given recent population growth and provides adequate capacity for future residential and commercial development to take place.

Will the trunk be built all at once or in sections and if so, what would the construction timeline be for each section?

We are in the process of hiring a contractor for the project at which point they will develop a construction plan that will detail section sequencing along with timelines. We will communicate this on our website once we learn these details. 

When will construction begin and how long will it take?

Construction is planned to begin in Spring 2025 and will last for approximately two to three years.

How will I know about construction and its impacts in my area?

We will notify residents through mailing a construction notice and we will also update our website regularly. 

Will Bowdale Crescent NW be closed during construction?

No, we will be widening the Bowdale Crescent ramp to allow vehicles to turn and get access to the Community. 


This information has no legal status and cannot be used as an official interpretation of the various bylaws, codes and regulations currently in effect. The City of Calgary accepts no responsibility to persons relying solely on this information. Web pages are updated periodically. ​

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