The legal fight over the Site C dam isn't over with Premier John Horgan's announcement today that his government will complete the $10.7-billion Site C dam.

The chiefs of the West Moberly and Prophet River First Nations have responded by declaring that they will seek an injunction to halt construction.

They're also going to launch a lawsuit alleging infringement of their treaty rights.

"It was John Horgan's NDP that demanded a Site C inquiry by the B.C. Utilities Commission, and the results they received from it were clear: no need for the power, better alternatives once we do, and no advantage to ratepayers to proceed," West Moberly chief Roland Willson said in a news release. "With those findings, the only responsible choice was to immediately stop destroying the Peace River Valley."

According to the B.C. government, the band has a population of 308 and is a member of the Treaty 8 First Nations.

The chief of the 249-member Prophet River First Nation, Lynette Tsakoza, urged allies of her band to keep fighting. It's also a signatory to Treaty 8.

"The province doesn't have billions of dollars to waste on a make-work boondoggle for power we don't even need," she stated.

Horgan has previously acknowledged that First Nations have entrenched constitutional rights in the region where the Site C dam is being built.

In 2014, Horgan also declared that the dam would violate those rights.

Earlier this year, the Supreme Court of Canada refused to hear appeals from the West Moberly and Prophet River First Nations alleging that the B.C. and federal governments did not meet their legal obligations to consult in advance of approving the Site C dam.

Willson, however, claimed that the recent provincial regulatory review has provided a legal opening.

"With the BCUC's report in hand, we're confident that the court will grant our injunction," Willson said. "Usually, courts are reluctant to hold up a project because of economic impacts. But with the BCUC's report in hand, the court can actually save British Columbia billions of dollars and protect our constitutional rights at the same time."

Meanwhile, the chief of the Blueberry River First Nation has also expressed his disappointment in the government's decision to complete the Site C dam.

“Blueberry River is the First Nation closest to the dam," Chief Marvin Yahey said in a news release. "We will be the ones most impacted by it. We are being pushed out of another area that has always been critical to our members and our way of life. The province is not taking our rights, or its duties under Treaty 8, seriously.”

He pointed out that members of his First Nation have supported themselves by trapping, hunting, fishing, gathering plants, and other activities in the Peace River Valley. He also claimed that the Site C dam will flood gravesites where the band's ancestors are buried.

“Premier Horgan could have done the right thing here and taken a step toward reconciliation, but he chose not to," Yahey insisted. "Site C will be the single largest infringement of our rights under Treaty 8, and there is no justification for it.”