The Burns Bog Conservation Society has lost its court battle against the federal government regarding the South Fraser Perimeter Road's impact on the environmentally sensitive wetland.
"It's odd because we thought the judgment would have to do with whether or not we had standing, but it went on to something else," said society president Eliza Olson.
The Federal Court made its ruling last week.
The society took Ottawa to Federal Court in Vancouver, claiming the federal government breached an environmental covenant to protect the bog when the highway was allowed to be built adjacent to the wetland.
The group and others opposed to the alignment of the SFPR contend the new highway will have a significant impact, despite the Gateway Program's assurances that mitigation measures will address concerns.
Olson contends the highway will disrupt the natural hydrology and hydrochemistry, and destroy and fragment wildlife and their habitat.
The society also contends the highway's proximity contravenes the Canadian Environmental Assessment Act and the federal Species at Risk Act.
Using a grant from West Coast Environmental Law to launch court action, the group noted the federal government is an equal, and therefore responsible, partner.
The judgment last week, however, found the society did not address the legal argument presented by the government, and did not provide any evidence to substantiate the society's concerns regarding impact to Burns Bog from highway construction.
"It's obvious the federal government left a big loophole in the conservation covenant. Everybody should start looking at their conservation covenants to see if they have any validity or not," said Olson.
"It's interesting the federal government talks about they have no fiduciary duty, so does that go for everything?" she asked.
In 2004, four partners - federal, provincial, regional and municipal governments - jointly purchased 2,042 hectares (5,045 acres) of Burns Bog to be protected as an ecological conservancy area.
A legally binding conservation covenant was placed on the land to ensure it is protected.
The new $1 billion highway is being constructed outside that conservancy area.
Delta was not named in the lawsuit.
Delta council has repeatedly stated it did not have the legal ability to intervene, and obtained an outside legal opinion stating the same.