VICTORIA — The B.C. government pledged Tuesday to spend billions building a big new dam in the northeast, setting the stage for a courtroom showdown with furious First Nations and other landowners over the most-expensive project in the government’s history.

Premier Christy Clark approved the Site C dam, saying the almost-$8.8 billion megaproject will provide future generations with clean, reliable hydroelectricity, like that already generated by other dams on the Peace and Columbia rivers.

“In the life of any province, there are moments where each of us have an opportunity, a responsibility, to make big decisions, ones that are going to matter, in this case, for a century,” Clark said at the legislature. “Today is that day.”

It would be BC Hydro’s first new dam in more than 30 years, and likely the last major hydroelectric project of its kind on the Peace River. It would put the BC Hydro back into the business of generating its own power after years of increasing reliance upon small-scale private power projects.

Energy Minister Bill Bennett said Site C will provide cheap, reliable power to help meet a demand for electricity that’s expected to jump 40 per cent in the next 20 years.

But, the dam would flood 5,557 hectares of land along 83 kilometres of the Peace River valley, from Fort St. John to Hudson’s Hope, destroying traditional territory of local First Nations and displacing residents who live and farm in the area.

Both aboriginal leaders and farmers have challenged the project in court. On Tuesday, they slammed the provincial government for charging ahead.

First Nations chiefs called the move “ill-advised and incredibly stupid,” and doomed to failure.

“The fight is just getting started,” said Chief Roland Willson of the West Moberly First Nation.

He said First Nations will be seeking injunctions to prevent permits from being granted and construction starting until legal challenges have been concluded.

Willson added the Yes decision on Site C puts all types of resource development under scrutiny for First Nations, including natural gas extraction in northeast B.C. needed to fuel billions of dollars in proposed liquefied natural gas (LNG) export plants on the B.C. coast.

“There’s already a massive footprint on the land up here. Now, there’s another large-scale hydroelectric dam. … We’ve got to do what we can to protect our way of life up here,” said Willson. “We are not just going to roll over and allow the systematic destruction of our lands anymore.”

The Doig River, Prophet River, West Moberly and McLeod Lake bands — all members of the Treaty 8 Tribal Association — have already launched a Federal Court action seeking to quash Ottawa’s environmental approval of the project.

University of BC. professor Elizabeth Edinger said that because claims of First Nations cover much of British Columbia, it’s hard to develop natural resource and industrial projects without proper consultation, which is required by law.

Edinger, an expert in constitutional law, said she could not speak to the merits of the legal challenges but said “they have some chance of, if not success, at least procrastination (delaying the project).”