After decades of industrial pollution, the Mohawk nation has succeeded in knocking down the Hogansburg Dam in New York.

A century after the first commercial dam was built on the St Regis River, blocking the spawning runs of salmon and sturgeon, the stream once central to the traditional culture of New York’s Mohawk Tribe is flowing freely once again.

The removal of the 3-metre Hogansburg Dam this autumn is the latest in the tribe’s decades-long struggle to restore territory defiled by industrial pollution, beginning in the 1980s with PCBs – toxic industrial chemicals – and heavy metals from the nearby General Motors, Alcoa and Reynolds Metal plants.

We're transforming it from a dangerous no-go zone to some place that's inviting and beautiful Eric Sunday, an apprentice in the cultural restoration programme

The clean-up under federal oversight is nearly complete.

The St Regis River project is the first removal of an operating hydroelectric dam in New York state and the nation’s first decommissioning of a federally licensed dam by a Native American tribe, federal officials say.

Paired with the recent success of North Dakota’s Standing Rock Sioux in rerouting a pipeline that they feared could threaten their water supply, the removal of the dam underscores long-standing concern over the health of tribal lands.

“We look at this not only as reclaiming the resources and our land, but also taking back this scar on our landscape that’s a constant reminder of those days of exploitation,” said Tony David, water resources manager for the St Regis Mohawk Reservation, which the Mohawks call Akwesasne.

Preserve the Mohawk language

The former industrial site will become a focal point in the Mohawks’ cultural restoration programme, funded by a $19m settlement in 2013 with GM, Alcoa and Reynolds for pollution of tribal fishing and hunting grounds along the St Lawrence River.

The programme partners young apprentices with tribal elders to preserve the Mohawk language and pass on traditional practices such as hunting, fishing, trapping, basket-making, horticulture and medicine.

Standing on the rocky edge of a shallow, rushing river that used to be stilled by a 100-metre-long concrete dam until bulldozers demolished it in September, David told the AP news agency that a new park would be built to showcase Mohawk artwork where the powerhouse once hummed.

On the opposite bank, a nature park will replace a treacherous tangle of industrial equipment, decrepit structures and rubbish.

“We’re transforming it from a dangerous no-go zone to some place that’s inviting and beautiful,” said Eric Sunday, an apprentice in the cultural restoration programme. “It creates opportunities to get people together, showcase skills, get more knowledge about our traditional ways and just appreciate nature.”

The dam removal re-established the river’s connection with the St Lawrence River and opened nearly 443km of stream habitat to migratory fish, including American eel, lake sturgeon, Atlantic salmon and walleye.

“The next town upstream was known by the Mohawks as ‘Place of the Salmon’,” David said. “Before salmon were extirpated from this river, people would be out in the shallows netting or spearing them to feed their families.”

The project is part of a larger movement that has dismantled almost 250 dams across the country since 2012, according to the conservation group American Rivers.

Most have been small dams no longer useful, but environmental groups and Indian tribes in the Pacific Northwest are pressing for the removal of large hydroelectric dams to restore salmon runs.