Major development projects such as the Site C dam in British Columbia's Peace River watershed could threaten up to $8.6 billion in ecological values, suggests a report commissioned by the David Suzuki Foundation.
Faisal Moola, a chief scientist with the environmental group, said the 56,000-square kilometre watershed is a "Fort Knox" of ecological wealth, with ecosystems providing benefits including clean air, clean water, carbon storage and flood and erosion control.
BC Hydro is proposing an $8-billion hydroelectric dam in the Peace River Valley, which would flood an 83-kilometre stretch of land along the river. It would be the third dam on the river, downstream from the W.A.C. Bennett and Peace Canyon dams.
Moola said carbon stored in forests, wetlands and grasslands are conservatively worth $6.7 billion to $7.4 billion a year, while other ecological services amount to $1.2 billion annually.
Policy-makers typically ignore ecological advantages because they appear to be provided by nature for free, he said.
The study, authored by ecological economist Sara Wilson from the Toronto-based firm Natural Capital Research and Consulting, included satellite images of the watershed and used modeling techniques to ascribe a dollar value to services such as water filtration by trees.
"We know for example that forests are really important in terms of filtering water, but on the other hand, grasslands and farmland are really important in terms of providing habitat for bees and pollinators, which is something that is critical to sustaining agricultural commodities," Moola said.
"If we actually make a decision to further degrade the amount of natural forest cover we have in an area, that will incur explicit costs. And in the case of water filtration, it's been very well documented that this will actually increase the cost to local municipalities to provide potable drinking water. And typically, those costs are downloaded to rate payers."
BC Hydro said in a statement that officials are reviewing the report, the project is undergoing a three-year, federal-provincial environmental assessment process, and the foundation presented its perspective at federal Joint Review Panel hearings last December.
The economic values in the report are for a watershed of about 5.6 million hectares but the amount of land that's expected to be flooded for the reservoir is about 5,550 hectares, the utility added.
"All new electricity-generation projects have effects and Site C is no different," the statement added. "While Site C has the potential to result in some significant effects, we believe those effects are justified by the need for the project, and the benefits it would provide for our province."
The utility has said the Site C dam would generate enough energy to power 450,000 homes a year.
Further development in the area could erode its ecological benefits, Moola said.
"The Peace region is already some two-thirds developed. Essentially, it's a perfect storm of logging, mining, conventional and unconventional oil and gas development. And there's a proposal to build a major dam on the Peace River that will further the cumulative impacts of industrial development on this region."
Along with the two existing dams, the region has more than 16,000 oil-and-gas well sites and about 8,500 petroleum and natural gas facilities. The area would also be the heart of B.C.'s proposed liquefied natural gas industry.
Earlier this year, a joint review panel concluded the dam would have significant adverse effects on the environment and wildlife. But it also said the benefits of the project are clear and there are few alternatives to provide the type of long-term, inexpensive energy source proposed by the Crown utility.
The panel report, released in May, did not give a clear yes or no answer. The federal and provincial governments are expected to release a final decision later this year.
Provincial Energy Minister Bill Bennett has said that if approved, construction could begin in January 2015, and the dam would be completed by 2024. He has also said that the benefits of the project will outweigh the impacts cited in the review.