The Supreme Court of Canada says it will not hear appeals from two B.C. First Nations in their court challenges of the $8.8-billion Site C hydroelectric project.

The court announced its decisions in the cases involving the Prophet River and West Moberly First Nations on Thursday. As is customary, it did not disclose its reasons.

The court's rulings are the latest legal victory for Site C, although the dam project still faces political hurdles. The NDP has said it would ask the British Columbia Utilities Commission to review the project, and Green Party Leader Andrew Weaver said he wants that review to be quick. The Liberals have said they oppose having a review and the time needed to carry it out would effectively kill the project.

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Site C is already under construction and has created more than 2,000 jobs, and the dam would produce 1,100 megawatts of power capacity – enough electricity for about 450,000 homes.

A 2014 report by a joint review panel found that while, the project had benefits, the dam would likely have a significant adverse environmental impact and would affect the treaty rights of First Nations, including Prophet River and West Moberly. The two First Nations have argued the province should not have issued an environmental assessment certificate for the project without assessing the adequacy of consultation and accommodation efforts.

But a B.C. Supreme Court judge dismissed their petition in 2015, ruling the two groups had been provided a meaningful opportunity to participate in the environmental assessment process. The judge also found provincial ministers did not have the jurisdiction to determine if the project unjustifiably infringed on treaty rights.

The B.C. Court of Appeal upheld that ruling. It agreed that the province did not have to determine whether the project infringed on treaty rights and said the consultation and accommodation efforts had been adequate.

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In addition to their efforts in the provincial courts, the Prophet River and West Moberly First Nations also launched cases at the federal level.

In a request to the Federal Court for a judicial review of Ottawa's authorization of the project, the First Nations said the federal government also should have assessed whether Site C infringed on treaty rights.

The Federal Court found there was no requirement to determine whether treaty rights had been infringed and said the consultation undertaken by the Crown had been adequate.

The Federal Court of Appeal later upheld that ruling.

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Roland Willson, chief of the West Moberly First Nations, wrote on Twitter that the Supreme Court of Canada's decision not to hear the cases broke his heart. He called the Site C project "unnecessary."

Mr. Willson has said flooding linked to Site C would affect fishing, hunting, trapping and sacred Indigenous sites that are thousands of years old. He did not return a message seeking comment on Thursday. The Prophet River First Nation also did not respond to a request for comment.

A BC Hydro spokesperson in an e-mail said legal challenges involving Site C brought by several groups have now been dismissed or discontinued.

The spokesperson said the Prophet River and West Moberly First Nations have also appealed Site C's water license to the province's Environmental Appeal Board. That hearing is scheduled for January.

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The BC Hydro spokesperson did not provide a response when asked for the company's reaction to the Supreme Court of Canada decision. The company also did not provide an update on Site C construction.

The NDP has said it will request a report from the B.C. Utilities Commission on Site C within six weeks, and a final report within three months. The Liberals have said that would delay at a potential cost of $600-million.