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).

• 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.
• Addition of a (proposed) 1.6 kilometre   multi-use pathway in the community of Valley Ridge.