The Holmes River hydro project consists of 10 generation sites along a 40-kilometre stretch of the river near McBride, B.C., generating an estimated 76 megawatts of electricity.
The Watershed Watch Salmon Society and the David Suzuki Foundation say the large-scale project should, under provincial law, undergo an environmental assessment.
But the B.C. Environmental Assessment Office has permitted the proponent to file each of the 10 hydro stations to be located along tributaries to the river as separate, smaller-scale projects that do not require assessment.
"That means it hasn't been subject to the rigorous and transparent scientific review and public participation that it could have been," said Aaron Hill, an ecologist with the Watershed society.
"We think that's necessary to ensure that these types of projects don't do undue harm to important wilderness values in B.C."
There are a large number of run-of-river projects underway or proposed in B.C. currently, and the decision to allow Holmes Hydro Inc. to split the project up for application purposes is a dangerous precedent, he said.
"It is a cleaner form of energy than, say, fossil fuels but it's still a major industrial development that could do significant harm to fish and wildlife in an important watershed," he said outside B.C. Supreme Court in Vancouver, where a hearing was scheduled for two days.
"It's important that when we do approve renewal energy projects we make sure that only the best ones go ahead and the best way to do that is through subjecting the projects to B.C.'s environmental assessment process."
An official with the provincial Environment Ministry declined to comment, as the matter is now before the court.
Jay Ritchlin, western Canada director of the David Suzuki Foundation, said his group is not necessarily opposed to this specific project.
"Had the right process been applied for environmental assessment, we would have had the opportunity to address the real issues around fish and wildlife habitat — but we can't," Ritchlin said.
"And no way can the people of British Columbia understand the cumulative effects of something like this if the proper assessments aren't done up front."
The Holmes River is home to chinook salmon, and the conservation groups are concerned that the water diversion involved in 10 hydro stations could impact a salmon population that feeds into the Fraser River.
The hydro plants to be built along the river would be linked by a transmission line connecting them to the provincial power grid. Each would generate between two and 10 megawatts of power.
Projects in B.C. that generate 50 megawatts or more must undergo an environmental assessment and Ecojustice lawyer Devon Page, who represents the conservation groups in the court action, said splitting the project up has allowed Holmes Hydro to circumvent the law.
The B.C. government has significantly weakened provincial assessment laws already, Page said.
"The laws we have left they're interpreting as loosely as possible so as to avoid conducting environmental assessments of environmentally harmful projects," he said.
The groups want the judge to overturn the provincial agency's decision, and order an environmental assessment, cancelling any permits that may have been issued so far.