Canada’s long history of harnessing water for energy means that many of the country’s hydropower plants have been in operation for more than a century. When Ontario Power Generation (OPG) needed to upgrade four 100-year-old generating stations on the Upper Mattagami River, the company relied on the expertise of Tetra Tech subsidiary BPR.

The project included demolition of the existing powerhouses, rehabilitation of the existing spillways, and construction of new powerhouses. When the project was completed, the total capacity of the four stations was more than doubled – from 21 MW to 44 MW. The projects have gross heads ranging from 10 to 38 meters.

We developed concepts and specifications for all civil, mechanical, and electrical engineering work, reviewed final designs and submittals, and monitored the work during construction. We successfully navigated the challenges of working on four sites concurrently, interacting with numerous stakeholders, and ensuring that the quality of both the on-site construction and off-site manufacturing met OPG’s quality standards. The project was completed under budget and ahead of schedule.

Services included:

• Simultaneous implementation of four projects
• Risk assessment and registry
• Definition of permits and authorizations
• Assistance for environmental assessment and First Nation's acceptance
• Preliminary subsurface investigations
• Assistance in dam safety assessments and rehabilitation
• Development of small hydro guidelines
• Conceptual design for all generating stations
• Assistance with the short-listing of contractors and water-to-wire suppliers
• Preparation of plans and specifications for tendering processes of water-to-wire supplier and design-build contractor
• Assistance with the evaluation of tenders and negotiation with the chosen contractor
• Review of final designs and submittals
• Document control
• On-site construction monitoring and commissioning assistance
• Off-site manufacturing quality assurance program
• Preparation of technical information for interconnection on the Hydro One network following their specific process and compliance with Independent Electricity System Operator (IESO) requirements