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Site C busts past major milestone with completion of dam

Filling of reservoir could begin this fall

The most expensive and some might say controversial infrastructure project in the history of B.C. has reached a milestone.

BC Hydro Monday (July 31) announced completion of the earthfill dam at the heart of the Site C project near Fort St. John.

The dam stands about 60 metres tall and stretches more than one kilometre across the Peace River. Completion of the dam, which is about 500 metres wide at its base and 10 metres at its top.

Construction of the dam started in 2021 following diversion of the Peace River. Most of the material comes directly from the site itself, while a conveyor belt five kilometres long supplied other material. Overall, crews placed 15.5 million cubic-metres of material, enough to fill the Great Pyramid of Giza six times, according to BC Hydro.

Crews will now start capping the dam and build roads across it. BC Hydro says the earthfill dam meets the Canadian Dam Association’s highest recommendations and will be able to withstand a major (one in 10,000 year) earthquake.

Completion of the dam the stage for filling the dam’s reservoir, which could get underway later this fall. Filling the reservoir would flood an 83-kilometre-long stretch of the river’s valley with the reservoir becoming two to three times wider than the current river.

Another key component for reservoir filling is the conversion of one of the tunnels that currently divert the Peace River around the project site. BC Hydro says that process requires the installation of large ring-shaped devices — so-called constrictions — inside one of the tunnels to restrict the flow of water with that work now underway.

Other key components of the dam still await completion before the reservoir can be filled.

They include the approach channel diverting the Peace River from its current course, so it goes around the earthfill dam and towards the powerhouse, where the water will generate electricity; spillways providing a safe path for floodwaters to escape downstream; the tailrace area carrying water away from the powerhouse, dam intake structures and components of the powerhouse itself.

RELATED: BC Hydro applies to leave some Site C construction debris to be flooded over

Construction of Site C began in late July 2015 and BC Hydro says the project remains on-track to have all six power-generating units in-service by 2025.

Once complete, Site C will provide the equivalent amount of energy needed to power about 450,000 homes or 1.7 million electric vehicles per year in British Columbia.

The project has also been a constant source of political, economic and environmental controversy, starting with questions about its necessity and its ever-changing price tag.

ReNew Canada, a publication tracking infrastructure projects across Canada, listed Site C as the most expensive infrastructure in all of Canada in 2022 with a price tag of $16 billion, almost double from the figure, when the BC Liberals had given Site C a green light in late 2014.

Site C had first emerged as a proposal in the early 1980s, only for the British Columbia Utilities Commission to turn it down, citing questionable forecasting.

But the project not only retained, but gained support among key decision makers during the premiership of BC Liberal Gordon Campbell and his successor Christy Clark eventually pushed the project across the approval line, with critics accusing the BC Liberals of having rigged the regulatory rules.

Her successor, former New Democratic premier John Horgan, decided against pulling the plug following a review, drawing criticism from both project opponents and supporters, who accused Horgan of being tepid about a major economic project for northern British Columbia.

Environmentalists fearing the loss of endangered species and their respective habitats; First Nations fearing the loss of culturally sensitive areas and economic opportunity; and private landowners have also challenged the project, but legal challenges failed to stop Site C, now coming closer to completion.


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Wolf Depner

About the Author: Wolf Depner

I joined the national team with Black Press Media in 2023 from the Peninsula News Review, where I had reported on Vancouver Island's Saanich Peninsula since 2019.
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