Edmonton’s combined sewer overflow (CSO) threatened the environmental stability of the North Saskatchewan River, which bisects the city and provides its drinking water. W12 was targeted as part of the West Edmonton Sanitary Sewer project.

W12 was designed as a syphon to convey the Rat Creek outfall overflow (responsible for up to 80% of Edmonton’s CSO volume) safely to the Gold Bar Wastewater Treatment Plant.

W12’s location within the footprint of abandoned coal mines proved extremely challenging for the construction team.

Limited access, uncertain ground conditions, usage of unfamiliar equipment and deep shafts suggested a challenging project.

SMA Consulting played a number of crucial roles in decision support.

We marshaled a vast array of innovative techniques such as FMEA, construction simulation and 3D and 4D visualization, which supported key decisions during the process. These methods were employed as part of our risk analysis, value engineering and constructability workshops.

SMA’s project controls ensured that information from multiple sources could be incorporated.

Our sophisticated decision support tools, together with our facilitated workshops, helped external experts to evaluate the project in a controlled environment and suggest revisions.

The project was completed with no safety issues and the CSO volume entering the North Saskatchewan River has been reduced, improving water quality for municipalities downstream.