Acid rock drainage into Peace River results in federal charges

FORT ST. JOHN, B.C. — An incident in 2018 where water ran over potentially acid-generating rocks before being drained into the Peace River resulted in BC Hydro and Site C’s main civil contractor being charged under the federal Fisheries Act.

BC Hydro released details on the incident in a Site C quarterly report dated between July 1st, 2022, and September 20th, 2022.

According to the report, Site C released approximately four million litres of water that had run over potentially acid-generating rocks into the Peace River. 

The report said the incident occurred in September 2018, when the Site C project area saw approximately 55 millimetres of rainfall. Water captured in holding ponds on site had run over potentially acid-generating rocks, according to the report.

During the rainfall, BC Hydro reports that the holding ponds hit capacity, resulting in a controlled release of the water into the Peace River over a 24-hour period. 

The report stated that the release of water was done to “protect the water management infrastructure and ensure the structural integrity of the holding ponds.”

In the report, BC Hydro said the incident was reported to provincial and federal agencies on September 9th. BC Hydro also reported that no impacts to fish or wildlife in the Peace River were detected. 

Still, immediately following the incident, Environment and Climate Change Canada began an investigation over the incident concerning the federal Fisheries Act. 

BC Hydro said they were made aware of the results of the investigation in October 2022. 

In the aftermath, BC Hydro was charged by the federal government with failure to notify of the deposit of a deleterious substance in a timely manner. BC Hydro’s main civil contractor, Peace River Hydro Partners (PRHP), received the same charge and an additional charge for depositing a deleterious substance into a waterway. All charges were laid under the federal Fisheries Act. 

A deleterious substance is any substance that could cause harm. In this case, the deleterious substance is the water that had run over possibly acid-generating rocks. 

According to a fact sheet written by the Center for Science in Public Participation (CSP2) for the Alaska Community Action on Toxics (ACAT), the environmental dangers of acid rock drainage is not actually the acid itself.  

Acid-generating rocks, and what’s known as acid rock drainage, is an occurrence most common in mining operations. It can also occur in cases of construction, such as Site C. 

The fact sheet explains that rocks with sulfuric content can create sulfuric acid when brought into contact with water and oxygen. This acid erodes rocks faster, which releases metals from the rock. Furthermore, sometimes certain bacteria that feed off of iron can begin to grow on the rock, speeding up the process and releasing more metals. 

When drained through natural rainfall or other drainage processes, the newly released metals impact the environment around them. The kind of metal in the water will change the effect it has on the environment. 

The fact sheet outlines how high levels of iron in water can build up and “cement” along the bottom of the waterway. Thus, starting a negative “domino effect” within flora and fauna of the ecosystem. 

BC Hydro said that any potentially acid-generating rocks in the reservoir will be covered once filled — something that could be happening as early as this year.

BC Hydro claimed that they are taking steps to mitigate the risk from potentially acid-generating rocks that will not be covered by the reservoir filling or the dam itself. BC Hydro said the results of these efforts will be reported in future quarterlies. 

While there is no word on how much either BC Hydro or the PRHP are being fined, it is well documented that fines under the Fisheries Act can be hefty. 

The largest fine ever handed out under the Fisheries Act for another case of depositing a deleterious substance in a waterway was to Teck Coal Limited in 2021. The company was fined $60 million for dumping waste from a coal mine into the upper Fording River. 

In response to a report from The Narwhal, Site C manager of public affairs and community relations, Greg Alexis, said that BC Hydro was aware of the charges and that the company would respond through the courts. 

“In the meantime, we will not be providing any further comment on the charges,” Alexis said. 

The full BC Hydro quarterly report on Site C can be read here

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