A key habitat in "North America's bird nursery" will be harmed, nests will be drowned and important feeding areas flooded if B.C. dams the Peace River at Site C, according to Environment Canada.
In a submission filed with a joint review panel studying the proposed hydroelectric development near Fort St. John, Environment Canada says 247 bird species use the area, including up to 30,000 songbirds and woodpeckers that breed "in the reservoir impact zone."
And many species – 11,000 shorebirds in one month alone – migrate along the river corridor. The Peace River Valley provides a rare, low elevation flyway through the Rocky Mountains into northern Alberta, Environment Canada stated in its report.
In its environmental-impact statement, BC Hydro acknowledged the proposed dam will cause "habitat alteration and fragmentation" but stated that for most bird species the damage will be local and transitory.
BC Hydro said the overall impact on songbirds "is characterized as moderate," but noted the loss of some valley bottom forest "could reduce populations to levels lower than present … and [some] populations may not be fully recoverable."
Environment Canada, however, said BC Hydro's assessment isn't thorough and the federal agency disagreed with the provincial corporation's conclusions.
"In EC's opinion, project effects would be broader and longer-term that hitherto identified and, for some species, more detrimental," Environment Canada stated.
"BC Hydro narrowed the focus of baseline data, assessment of effects, and corresponding mitigation to a small number of species at risk," the report said. "As a consequence of this approach, the assessment, in EC's opinion, fails to capture or represent the life requisites and effects pathways for migratory birds."
Environment Canada was also critical of BC Hydro for providing "insufficient information … to assess the level of risk" to birds that winter in the area.
The report said the Peace River Valley is vital to many birds because it is milder.
"Habitats of the Peace River canyon are expected to be particularly important to birds in migration, especially in spring, as these habitats are warmer, more sheltered, and therefore subject to less wind and cooling than the adjacent upland areas," said the report. "EC thinks the most important role of the Peace River to migrant waterfowl occurs in March when the river is open but nearby wetlands and streams are still frozen. It is the first and most significant open water habitat available to migratory birds."
The report said the Site C dam is located in a rich boreal mosaic of forests and wetlands.
"The boreal forest is considered North America's bird nursery, providing breeding habitat for over 300 species of birds," states the report. "While some bird species are increasing, many, like aerial insectivores, shorebirds, forest and grassland birds, have been in steady decline for many years … Habitat destruction is the major cause of declines … and transmission lines also kill a large number of birds."
The Environment Canada report said Site C "has the potential to kill individuals or destroy active nests of migratory birds" through vegetation clearing for the dam, reservoir and other infrastructure, and through the filling and operation of the reservoir.
BC Hydro proposes developing bird, fish and wildlife programs to mitigate environmental impacts, but Environment Canada specifically recommends a wetlands compensation program, developed in conjunction with the federal government and First Nations.
"EC does not agree with the implicit assumption that nest boxes and the gradual re-establishment of vegetation would be sufficient to reverse project effects," stated Environment Canada.