Bonnybrook Wastewater Treatment Plant – Outfall & D Expansion Works
Client:
City of Calgary
Location:
Calgary, Alberta
Year:
2022
Project Scope
Whissell executed the Bonnybrook Wastewater Treatment Plant (BBWWTP) outfall and associated works a technically demanding in-river civil construction project requiring the installation of large-diameter precast concrete diffuser pipes below the Bow River riverbed to discharge treated effluent from the Bonnybrook facility.
- Design, supply, and installation of four 1,800 mm diameter precast concrete pipes with 700 mm diameter diffuser openings, installed below the Bow River riverbed
- Design, supply, and installation of a rock and granular fill cofferdam to enable excavation and pipe bedding material placement
- Coordination of all works within instream restrictive periods
- Cofferdam removal during the spring non-restrictive access period
- Coordination with multiple subcontractors and trades on a congested plant site
Challenge & Mitigation
The project required strict adherence to instream work restriction windows, meaning all in-river construction had to be completed and the cofferdam removed within defined seasonal periods. Managing pump and hose placement to avoid interference with the pipe installation while coordinating with multiple subcontractors on a busy treatment plant site required detailed daily sequencing and continuous communication across all trades.
Value Add Solution
Whissell's experience with river-adjacent and in-water civil construction, including previous work on the Bow River at the Enmax Shepard Energy Centre and the Laycock Park Sanitary Siphon, provided the team with the environmental management expertise and instream construction protocols needed to execute the cofferdam construction and pipe installation within the restrictive period windows without regulatory incident.
