Hydro Dams and Stranded Fish - BC Can Do Better

Every year in BC, thousands of fish die in mass-stranding events. Solutions do exist, but public pressure is needed

By Desiree Mannila

Crooked River

Crooked River | Image: ©Daniel Case

Despite having its own significant issues with greenhouse gas emissions, hydroelectricity is widely seen as a source of “clean” energy. However, the industry has introduced a wave of issues for vulnerable fish populations and public health across the province.

In an interview with Watershed Sentinel, Department of Fisheries and Oceans (DFO) representative Daniel Sneep summarizes the provisions of the Fisheries Act – “you can’t harm, alter, disrupt habitat, or kill fish.” However, he acknowledges that “hydroelectric facilities and their operations very often result in those sorts of events.” He explains that “many of the dams in the province were built many decades ago before much attention was given to those effects on the environment.”

Left for dead

Imagine walking up to a riverbed – its thunderous flow replaced with haunting silence, the air tainted by the stench of decomposing fish. You race from puddle to puddle, hoping there are fish that have yet to become victims to scavengers or suffocation. Though unpleasant, this is the reality for those unfortunate enough to come across a mass-stranding event.

Kyle Donaldson, a BC Hydro representative, explains that hydroelectric operations can be used to respond to environmental conditions, which may result in habitat loss and fish stranding due to flow alterations. BC Hydro operates in 41 locations across the province, and to date, tens of thousands of fish have succumbed to stranding from flow changes at BC Hydro facilities.

At the Hugh L. Keenleyside Dam/Arrow Lakes Generating Station and Brilliant Expansion Generating Station situated in the lower Columbia and Kootenay Rivers, regular flow reduction events appear to be killing thousands of fish annually. From April 2017 to April 2018, BC Hydro assessed 16 out of 19 flow reduction events which resulted in around 11,922 stranded fish, 42% (5,007) of which suffered fatalities. From April 1, 2019, to April 1, 2020 BC Hydro assessed 16 out of 28 reduction events, estimating 10,281 stranded fish – approximately 43% (4,420) of these fish perished.

DFO representative Daniel Sneep states that there have been “dramatic benefits to the fish populations” in situations where BC Hydro responded to public pressure to remove dams in the area.

On the Lower Coquitlam River, BC Hydro studied four flow reduction events between May 1, 2019, and April 1, 2020, which resulted in a total of 4809 fish strandings, approximately 722 of which resulted in fatalities. 96.3% of the affected fish were coho salmon.

BC Hydro has also released data from the Lower Duncan Dam indicating around 14,491 fish were observed in stranding events between 2006 and 2019. And in 2017, a mere 13-minute disruption at the John Hart Generating Station in Campbell River resulted in the loss of at least 30 salmon fry.

In 2019, BC Hydro took responsibility for the deaths of around 300 salmon trapped due to flow disruptions from the Daisy Lake Dam above the Cheakamus River – and in October 2021, another stranding event resulted in an estimated 7,324 fish deaths. Both events took place after BC Hydro had implemented the Cheakamus River Adaptive Stranding Protocol in 2018 to mitigate fish stranding. In a press release, The Sḵwx̱wú7mesh Úxwumixw (Squamish Nation) expressed that they question whether the facility “can ever operate in a manner that recognizes the value of Indigenous ways in respecting and protecting our lands, waters, and the life within it.”

Saved by the offset?

Sneep revealed that the existing Water Use Plan in the Cheakamus area addressed stranding, but not stranding events involving large salmon runs or events arising from substantial storms. He explains a new Water Use Plan is under review to address and offset these factors.

Sneep says punitive measures are a “bit of a gray area” that would boil down to “due diligence” and whether BC Hydro did the “best they could with the information they had, and the capability they have.” For the 2019 Daisy Lake Dam incident, he mentioned, “there’s probably a few things they could have done better,” such as deploying more salvage crews. Regarding the Cheakamus River mass stranding event in 2021, Sneep states there has been no final conclusion, although, he senses “it’s not something that we’re likely to pursue as charges under the Act,” since, he says, “we do believe they did exercise their due diligence.” He explained that BC Hydro will provide funding for the DFO hatchery on the Cheakamus River in an attempt to “offset the losses of those fish during those stranding events.”

Achieving fish passage

The construction, between 1912 and 1930, of the Alouette, Staves, and Ruskin hydroelectric facilities near Maple Ridge, required water diversions that left the outlet river dry. The obstruction from the dam cut access to habitat, resulting in a nearly complete loss of the salmon population. Through extensive lobbying from the community, in 1996 a final agreement with BC Hydro was made to increase the river flow from two cubic feet per second (cf/s) to an average of 92 cf/s. Following the return of water flow, salmon began to return to their home. Sockeye were believed to have been extirpated from the area after the dams were built, however, after an 80-year hiatus, they returned in the summer of 2007.

In an interview with Watershed Sentinel, executive director of the Alouette River Management Society (ARMS) Greta Borick-Cunningham recounts the hard work and determination of community volunteers to rebuild the salmon stocks through a hatchery and habitat enhancement. She explains that from April to June, BC Hydro conducts a spill that allows sockeye to escape the reservoir, but “the problem is when they get back, they have no way of getting up into the reservoir to then complete their life cycle.” Borick-Cunningham states that through an outdoor work program, low-security BC Corrections facility inmates run the hatchery, and use a specialized tanker truck to relocate trapped salmon back to the reservoir for spawning.

Borick-Cunningham believes that “all of the fish would benefit by having upper access to the watershed,” and states other areas such as Coquitlam and the Shushwaps share this dilemma. She explains that achieving fish passage requires a seven-step process called the Fish Passage Decision Framework. This includes establishing a business case endorsed by the Wildlife Compensation Program, which gets submitted to the BC Hydro board of directors, who then review the environmental, technical, and financial aspects of the proposal. ARMS has been in the process of convincing BC Hydro to build a fish passage on the Alouette River since 2007.

Measuring a fish

Photo courtesy of Greta Borick-Cunningham, Alouette River Management Society


Sneep comments that although DFO has no authority to force BC Hydro to integrate fish passages into their facilities, “pressure from DFO, from the public, from the First Nations in the area – a lot of pressure can be brought to BC Hydro to advance something like that.” Donaldson claims BC Hydro is currently trying to restore fish passage on the Salmon and Heber rivers on Vancouver Island, and is undergoing planning within the Coquitlam and Alouette watersheds.

Filet with a side of mercury

Stranding and habitat loss aren’t the only problems fish are facing from BC Hydro. Being a product of their environment, fish are susceptible to toxins in their area – whether through water absorption or prey ingestion. During the construction of dams, soil and vegetation are flooded, permitting elemental mercury to invade the aquatic ecosystem as methylmercury through the expedited decomposition of organic matter.

Women consuming fish with high methylmercury concentrations who are pregnant or nursing risk central nervous system damage to the child.

Methylmercury concentrations increase after a reservoir has been filled, and take up to 30 years to stabilize. In 2015, Chief Roland Willson from West Moberly First Nation tested 57 fish from Crooked River, located on the outskirts of Williston Lake – the reservoir created in 1968 by the W.A.C. Bennet Dam. 98% of the examined bull trout exceeded the 0.5 parts per million provincial guideline for mercury levels.

In adults, methylmercury ingestion may lead to blindness, deafness, cerebral palsy, depression, anxiety, memory problems, tremors, and irritability. Children risk cognition, fine motor skills, and speech and language development delays. Women consuming fish with high methylmercury concentrations who are pregnant or nursing risk central nervous system damage to the child.

Public pressure needed

Donaldson states BC Hydro is “committed to protecting the environment” and believes “through our Water Use Plan process, BC Hydro develops and implements plans to reduce those impacts.” Additionally, Donaldson asserts BC Hydro is “investing significant resources to address impacts,” and providing funding for the Fish and Wildlife Compensation Program.

Sneep states that there have been “dramatic benefits to the fish populations” in situations where BC Hydro responded to public pressure to remove dams in the area. He explains many dams across the province are aging and might be rebuilt or removed. “So we see that as a positive, as an opportunity to restore some of those ecosystems.

Desiree Mannila (Pa x ala) is a proud member of the Da’naxda’xw first nation. In addition to her new ventures with journalism, she is a full-time mom and student at Thompson Rivers University.

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