Cumberland House Cree Nation (CHCN) is suing the Saskatchewan government for failing to protect its most vital resource: the Saskatchewan River Delta, North America’s largest inland delta.

On Tuesday the First Nation, situated in the marshy forest in northcentral Saskatchewan near the Manitoba border, filed a lawsuit against the province for infringing its constitutionally protected Treaty rights to maintain its way of life.

“In Treaty No. 5, CHCN’s ancestors agreed to share the lands and waters of its territory with settlers. In exchange, the Crown promised that CHCN would be able to continue to hunt, fish and trap, and maintain its way of life,” the First Nation said in a news release Tuesday.

“The Saskatchewan River Delta is a place of outstanding ecological importance. It has historically been a wetland of astonishing productivity, providing habitat for vast populations of migratory birds, furbearing animals and fish.”

Now, the First Nation says the vital wetland is in “ecological crisis” and drying up because of industrial and agricultural activities upstream — including hydroelectric dams, irrigation and fertilizer-intensive farming. It says animal and fish populations have plummeted, and the water is no longer safe to drink.

“For far too long the Province of Saskatchewan has disregarded the Delta and our rights,” Cumberland House Cree Nation Chief Rene Chaboyer said in the release.

“Cumberland House Cree Nation is suing the province for approving and supporting these industries “without any credible plan for managing their cumulative impacts on the delta.”

An environmental consultant working with Cumberland House says the delta provides an irreplaceable service to the broader climate.

“The continued degradation of the Delta due to a lack of responsible management would result in the loss of one of Canada’s largest carbon sinks and irreversible impacts upon wildlife populations,” said Aaron Kuchirka, founder of Climate Smart Services.

This is not the first time Cumberland House Cree Nation has sued to protect the delta.

In 2023, it sued the provincial Water Security Agency and SaskPower after it renewed the licence for two upstream hydroelectric facilities nearby, the E.B. Campbell Dam and the Nipawin Dam.

In those cases, and later in a 2024 appeal, the First Nation argued the two Crowns failed to meet their duty to consult when SaskPower’s licences were renewed for the two dams.

The claims were later dismissed.

It remains to be seen what a King’s Bench judge will make of the current case, which is broader in scope.

Cumberland House Cree Nation is located about 450 kilometres northeast of Saskatoon, adjacent to the Northern Village of Cumberland House, the oldest community in Saskatchewan and one with historic ties to the fur trade and the Hudson’s Bay Company.