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BC Hydro shores up Site C river diversion channel

Diversion tunnels move 3,000 cubic metres of water per second
Erosion along the upstream river diversion tunnel outlet at Site C is seen in this reader submitted photo.

BC Hydro is shoring up its river diversion outlet at Site C.

Photos sent to Alaska Highway News this week show the upstream tunnel outlet flowing at full capacity with what appears to be some erosion along one side of the outlet channel. 

Site C spokesperson Dave Conway confirmed crews are doing maintenance work in the area.

"This work involves enhancing the diversion channel area with larger rip-rap (big rocks) than what had already been placed there during construction for river diversion," Conway said in an email.

"This work will address the potential of future erosion from occurring in the area and we expect the work to be completed in May."

The diversion tunnels were completed last May during the first wave of the COVID-19 pandemic, with the Peace River diverted at the end of September.

The tunnels are 750 metres long and 11 metres in diameter, and move 3,000 cubic metres of water per second. That's allowed contractors to move into the main channel of the river to begin building the kilometre-long earthfill dam, which will stand 60 metres tall.

A recent geotechnical review of the now $16-billion project found that foundation enhancements are needed for the dam’s spillway and powerhouse. That's led to a one-year construction delay, pushing the dam's in-service date to 2025.

"To be clear, this work has nothing to do with the geological conditions of the site," Conway said. "There is also no risk to the diversion tunnels or any of the other infrastructure around the tunnels. The diversion tunnels are performing as expected."

As of Tuesday, there were 1,274 workers at camp, including 8 in isolation. BC Hydro reports five active COVID cases among the workforce, with two new cases reported Monday. Worker vaccinations are expected to start this month.

Email Managing Editor Matt Preprost at