194th Street Priddis Slough Crossing – Earthworks & Underground
Client:
City of Calgary
Location:
Calgary, Alberta
Year:
2018
Project Scope
The 194th Street Priddis Slough Crossing is one of Whissell's most comprehensive heavy civil undertakings, a multi-discipline program combining bulk earthworks, large-diameter underground utilities, structural construction, and full surface paving across a challenging low-lying corridor. A critical geotechnical component was the installation of 225,000 wick drains to accelerate consolidation of soft, compressible soils across the slough crossing alignment, requiring precise drain spacing, installation sequencing, and ongoing settlement monitoring before road construction could proceed.
Earthworks:
- 650,000+ m³ of imported fill material and 25,000 m³ of onsite earthworks
- 225,000 wick drains installed to accelerate consolidation of soft, compressible soils
- Large-diameter storm sewers (up to 1950mm) and water main installation
- Tunnelling operations, bridge abutment construction, and full surface paving
- Surcharge and settlement monitoring program in collaboration with the geotechnical engineer of record
Underground:
- Large-diameter storm sewer installation up to 1,950 mm diameter, including all associated manholes, catch basins, and outfall structures
- Watermain installation including tie-ins to existing municipal water distribution infrastructure
- Trench excavation, shoring, bedding, and backfill for deep utility installation across the low-lying slough corridor
- Coordination of underground utility installation sequencing with the active earthworks and wick drain consolidation program
- Surface restoration and reinstatement upon completion of underground works
Challenge & Mitigation
Managing the sheer volume of imported fill while maintaining drainage control across a low-lying, wetland-adjacent corridor demanded continuous coordination between earthworks, drainage, and structural crews. Whissell developed a detailed surcharge and monitoring program to confirm that the subgrade had achieved sufficient consolidation strength before road construction could proceed, a critical quality gate that protected the long-term performance of the road structure.
Value Add Solution
Whissell's constructability expertise in soft ground earthworks including the wick drain installation program and real-time settlement monitoring, which allowed the project to advance on schedule despite the geotechnical complexity of the slough crossing alignment. The self-performance of both earthworks and underground utilities under a single contract eliminated interface risk and kept the program coordinated and on budget.
