Site C Dam: Comprehensive Assessment of Impacts on the Peace River Watershed

The Site C Dam represents one of British Columbia's most significant hydroelectric developments and most controversial infrastructure projects. This report examines the wide-ranging impacts of this major development on the Peace River Watershed, detailing environmental, social, agricultural, and economic consequences of the project.

Peace River Watershed: An Ecological Treasure

The Peace River Watershed in northeastern British Columbia represents a unique and ecologically significant region. According to research by the David Suzuki Foundation, the watershed supports 188 sensitive species including grizzly bears, wolverine, bighorn sheep, woodland caribou, short-eared owl, and bull trout4. The region provides critical wintering habitat for diverse animals including moose, elk, and deer, with important moose calving grounds located along riverbanks and small islands throughout the river4.

Land cover analysis indicates forests are the dominant ecosystem type, covering about 64.4% of the study area, followed by wetlands (9.2%), grasslands (7.8%), and various other habitats4. The Peace River Valley serves as a vital wildlife corridor for migrating birds and wide-ranging species such as caribou, wolverine, lynx, and grizzly bear4. This ecological diversity is supported by the region's unique topography, which varies from Rocky Mountains in the west to prairies in the east, creating a mosaic of habitats that sustain remarkable biodiversity4.

Unique Hydrological Characteristics

The Peace River is already regulated by two existing dams – the W.A.C. Bennett Dam and Peace Canyon Dam. Site C represents the third dam on this river system, located approximately 80 kilometers downstream from the W.A.C. Bennett Dam1. The river's complex hydrology supports extensive riparian habitats that are critical to regional wildlife populations and ecosystem services45.

Environmental Impacts

Habitat Loss and Fragmentation

The Site C reservoir will flood 83 kilometers of the Peace River valley, 10 kilometers of the Moberly River valley, and 14 kilometers of the Halfway River valley1. This flooding will destroy critical habitat for numerous species. The Joint Review Panel for the project determined there would be significant adverse environmental effects for dozens of species, including aquatics, vegetation, wildlife, and cultural heritage8.

Wildlife studies identified that breeding habitat of Canada, Cape May and Bay-breasted Warblers, Yellow Rail, and Nelson's Sparrow will be significantly affected by the dam and reservoir creation9. According to environmental assessments, "the primary effect of the project on wildlife resources is considered to be habitat alteration and fragmentation"9.

Impacts on Endangered Species

At least 63 endangered, red-listed, blue-listed, at risk, threatened, and species of special concern make Site C their home7. These include 30 species of migratory birds, 23 species of invertebrates, 6 species of mammals, 2 species of raptors, and 1 amphibian species7. Some plants like the Peace Daisy and Persistent-sepal yellowcress are found only in the Peace River Valley and would be extinguished by the dam7.

Water Flow and Quality Changes

Once operational, Site C will alter water flows and levels in the Peace River. Downstream water levels directly below the dam are expected to fluctuate by up to 1 meter compared to the current 48 cm fluctuation1011. These effects will diminish with distance from the dam as tributary inputs moderate the impacts10.

Water temperatures will also be affected, with the river becoming slightly warmer (0.3°C to 1.5°C) between July and January and cooler (0.4°C to 0.9°C) during the rest of the year in the area immediately downstream of the dam11. Water clarity will increase due to the reservoir trapping sediments, though large contributions from downstream tributaries will minimize this effect beyond the immediate dam area10.

Fish Population and Methylmercury Contamination

The dam will significantly impact fish populations through habitat alterations and methylmercury contamination. BC Hydro has implemented a "trap and haul" facility costing approximately $25.5 million to build and $1.5 million annually to maintain, designed to transport fish past the dam for the next 100 years13.

Fish methylmercury levels are predicted to increase by an average of three to four times the baseline level in the newly created reservoir and will take approximately 20-30 years to return to a new baseline15. Downstream of the dam, fish methylmercury levels are expected to initially double before gradually returning to baseline levels15. This contamination poses significant health concerns for communities that rely on fish as a food source14.

Impacts on Indigenous Communities

Treaty Rights and Traditional Practices

The Site C dam is located within Treaty 8 territory and will significantly impact First Nations' rights and practices. The federal-provincial environmental assessment found the dam would cause "significant adverse effects" to First Nations' fishing, hunting, and trapping16. The assessment concluded the project would "severely undermine" First Nations use of the area and would submerge burial grounds and other sites of cultural significance17.

In 2019, the United Nations Committee on the Elimination of Racial Discrimination called for the B.C. government to suspend construction until the project obtained the "free, prior and informed consent" of Indigenous Peoples16. West Moberly First Nation has pursued legal action, arguing the dam violates rights established in Treaty 819.

Cultural Heritage Losses

According to the Joint Review Panel findings, Site C would cause significant adverse effects on "physical heritage resources" and "cultural heritage resources for both Aboriginal and non-Aboriginal people"8. The project will submerge 78 First Nations heritage sites, including burial grounds and places of cultural and spiritual significance16.

Agricultural Impacts

Loss of Productive Farmland

Site C will result in the permanent loss of agricultural land, though estimates of the impact vary. According to BC Hydro, approximately 3,800 hectares of Class 1 to 5 agricultural lands will be permanently lost, representing about 1% of the available agricultural land in the Peace region21. However, critics argue the impact is much more severe, with some reports suggesting up to 9,429 acres (approximately 3,815 hectares) of prime farmland will be flooded23.

Soil scientist Wendy Holm has stated that "the land to be flooded is capable of providing an annual, local, sustainably produced supply of fresh vegetables to over a million people"23. The microclimate of the Peace River valley allows for greater agricultural diversity than surrounding areas, making this land particularly valuable2223.

Food Security Implications

The loss of productive farmland raises concerns about long-term food security in the region and province. Critics point out that 45% of foods that could be economically grown in British Columbia are currently being imported23, suggesting that preserving agricultural land should be a priority.

The Joint Review Panel concluded that "the permanent loss of the agricultural production of the Peace River valley bottomlands included in the local assessment area of the Project is not, by itself and in the context of B.C. or western Canadian agricultural production, significant"21. However, they also acknowledged that the loss would be significant to the farmers who bear that loss directly8.

Economic and Energy Considerations

Project Cost Evolution

The cost of the Site C project has increased dramatically since its inception. Initially announced in 2010 as a $6.6 billion project27, the cost was later estimated at $8.8 billion13 22, then revised to $10.7 billion18. In February 2021, the B.C. government announced that the cost had ballooned to $16 billion19, making it the most expensive publicly funded infrastructure project in B.C. history16.

Energy Production and Demand

When completed, Site C will provide 1,100 megawatts of capacity, increasing BC Hydro's current supply by 8%23. It will produce approximately 5,100 gigawatt hours of electricity annually – enough to power the equivalent of about 450,000 homes or 1.7 million electric vehicles per year2.

However, a UBC report questioned the economic viability of the project, finding that "BC Hydro's predicted demand for electricity has dropped significantly"20. The report suggested that electricity from Site C might not be fully needed for nearly 10 years after completion, potentially resulting in exports "at prices currently far below cost" and losses of at least $1 billion20.

Geological Challenges

Serious geological issues have emerged during construction, further complicating the project. The dam is being built on shale bedrock that contains bedding planes, areas that separate layers of rock, which have shown signs of instability28. This has necessitated additional engineering solutions, including extending the foundation deeper into the rock and installing up to 125 steel and concrete piles to anchor the structure28.

Experts have raised concerns that the region's geological characteristics, combined with seismic activity from nearby fracking operations (which triggered over 10,000 earthquakes in 2017-2018 alone), could pose significant risks to the dam's stability and safety29.

Conclusion

The Site C dam represents a transformative infrastructure project with far-reaching consequences for the Peace River Watershed. While providing clean energy capacity for British Columbia's future needs, it comes with substantial environmental, social, and economic costs.

The project will permanently alter an ecologically rich river valley, impacting dozens of plant and animal species, including several that are threatened or endangered. Indigenous communities will lose significant cultural sites and traditional use areas, raising serious concerns about treaty rights. The flooding of productive agricultural land represents a permanent loss of food production capacity in a uniquely productive microclimate.

As construction continues toward completion in 2025, the full scope of these impacts will become increasingly apparent. The complex balance between energy needs, environmental protection, Indigenous rights, and economic considerations highlights the challenging nature of major infrastructure decisions and their lasting consequences for watersheds like the Peace River.

[Note: This report is based on publicly available information as of April 22, 2025, and the cited references may not represent the most current status of the project.]

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Tuesday, April 22, 2025