Minnesota Chippewa bands will do their own assessment of Enbridge’s Line 3 proposal, looking at the “cumulative impact” of the pipeline on American Indians.

The Chippewa, also known as the Ojibwe or Anishinaabeg, have long been opposed to Enbridge’s plan to replace its aging and corroding Line 3 pipeline. The new 340-mile pipeline would run across northern Minnesota to Enbridge’s terminal in ­Superior, Wis.

While the new Line 3 wouldn’t cross any reservations in northern Minnesota, it would go through lands where Indians have treaty rights to hunt, gather and fish. They are concerned about the effect of a spill.

The Chippewa bands’ assessment, to be conducted with the environmental activist group Honor the Earth, will produce an “Anishinaabe-centric” report on environmental, social and legal issues, according to a statement.

The report will be submitted to the Minnesota Public Utilities Commission, which is slated to decide Line 3’s fate in April.

There are seven Chippewa bands in Minnesota, and five of them — White Earth, Leech Lake, Fond du Lac, Mille Lacs and Red Lake — are intervenors in the PUC process, meaning they individually have made formal comments. The Nett Lake band will also join the study.

The bands, as well as environmental groups, have been critical of the Minnesota Department of Commerce’s environmental impact statement, or EIS, on the Line 3 project.

The EIS contained “blatant inadequacies,” Joe Plumer, legal director for the White Earth band, said in a statement. The department could not successfully integrate the tribes’ “worldview” into the impact statement, he said.

The department’s assessment did conclude that the proposed pipeline — and any of its alternative routes — would have disproportionately negative impacts on American Indians.

As part of the bands’ report, they will include information from five public hearings for tribal and nontribal members beginning Wednesday at the Shooting Star Casino on the White Earth Reservation in Mahnomen, Minn. Further meetings will be held on other ­reservations.