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Over two days last November, an aircraft outfitted with high-definition thermal imaging equipment flew the 340-mile length of the Line 3 oil pipeline across Minnesota. It was scouting for evidence of more construction-related damage to the state's aquifers.

Oil has been flowing through the completed pipeline for months now, but the White Earth Band of Ojibwe — Minnesota's largest Native American tribe with about 20,000 members — continues fighting the project in court, and through extraordinary surveillance efforts.

The band now says their aerial imaging found six more sites that indicate potential breaches to public groundwater resources.

Both Enbridge and the state Department of Natural Resources (DNR) say they've done aerial checks of their own and haven't found any breaches beyond the three the DNR confirmed March 20, which spilled nearly 300 million gallons of groundwater — about what a city the size of Brainerd would use in a year.

But the first of the breaches went undisclosed for at least five months. The Band and environmental groups such as the Sierra Club and MN350, which shared the cost of the $52,000 flyover, say they don't trust the process to protect the resources.

"The environment is that important to us, our natural environment," said White Earth citizen Dawn Goodwin, a key pipeline opponent and co-founder of RISE Coalition, an Indigenous women's environmental group. "I live here and my ancestors lived here."

The state already fined Enbridge for that first breach but the DNR is still working on comprehensive penalties for all three breaches. Meanwhile, Minnesota Attorney General Keith Ellison is reviewing the first incident for potential criminal charges.

White Earth tribal lawyer Frank Bibeau said they will share the new flyover information with Ellison's office. The images are also being presented in tribal court as evidence in the band's groundwater legal fight with the DNR.

The groundwater problems are exactly what Line 3 opponents warned could happen on such a major project cutting through Minnesota's watery northern landscape, Bibeau said.

"Now we have to live with it and they get paid the big money for destroying our planet," Bibeau said. "This stuff is irreparable for a millennia. Those are hard words to think about."

DNR Deputy Commissioner Barb Naramore said the agency is aware of the flyover's basic findings but hasn't yet received copies of the aerial footage and technical information.

Juli Kellner, a spokeswoman for Calgary-based Enbridge, said the company did not know about the tribe's new claims.

"We have flown over and walked the route repeatedly and have worked with geologists, hydrologists, and the regulatory agencies," Kellner said. "The regulatory agencies have completed site visits and further investigation and we have found no further issues."

Jeff Broberg, a geologist collaborating with the White Earth Band, said he thinks the group found the possible new accident sites because regulators are only looking at problems Enbridge self-reported.

Naramore disagreed. The DNR did its own aerial inspections "of relevant portions of the line extending beyond the areas around the three known breaches" and found no others, she said. She noted that groundwater on the surface does not always mean an aquifer was damaged.

"If White Earth or any other parties furnish us with specific and actionable information that warrants additional investigation, we will follow up as appropriate," Naramore said.

The images captured by the tribe's contractor record the temperature difference between warmer groundwater and frozen ground. Broberg said they are examining more than a terabyte of data and plan to verify sites with inspections by foot. A final report will be out this summer.

One site they suspect of being another breach is about a mile from where Line 3 crossed under the Otter River in St. Louis County: "It has a real strong thermal fingerprint of warm water," said Broberg.

Litigation

The band's flyover results were first disclosed in court documents filed March 25 in the White Earth Band's tribal court of appeals, and first reported on the Healing Minnesota Stories website. They are appealing the tribal court's decision in March to dismiss the novel "rights of nature" lawsuit in which the lead plaintiff was wild rice, or manoomin, with its own rights to clean and undisturbed water.

The lawsuit challenges the DNR's permission to Enbridge to pump a maximum of 5 billion gallons of water from its construction sites. The band says the pumping during last summer's severe drought has harmed wild rice beds.

The Tribal Court dismissed the case March 10, saying it doesn't have jurisdiction because the alleged violations didn't occur on the reservation. A parallel case is pending in federal court.

Aquifers

The Line 3 breaches are unlikely to permanently damage the aquifers, said Timothy Cowdery, a hydrogeologist with the U.S. Geological Survey. Other scientists have expressed concerns about above-ground impacts and they go beyond the waste of a public resource.

Some are concerned the discharge of groundwater could lower the water pressure in the aquifers, potentially drying up wells or municipal water supplies. That's a particular concern during a drought, said Joe Magner, a licensed hydrologist in the University of Minnesota's Department of Bioproducts and Biosystems Engineering. Groundwater flowing out can also cause soil erosion on the surface and carry sediment into nearby wetlands, lakes and streams and damage those ecosystems, he said.

It's not clear whether any wells have been affected by the breaches. Clearbrook City Clerk Lucie Thompson said she's unsure whether the town draws from the same aquifer as the one Enbridge crews punctured near Clearbrook in January 2021, releasing at least 50 million gallons. But the city has two wells, she said, and the rupture "hasn't affected that."

The breaches can have other effects, including contaminating the aquifers and altering their chemistry in a way that damages plants and animals, said Kristen Blann, a freshwater ecologist at The Nature Conservancy.

The Clearbrook breach threatens a nearby calcareous fen complex that the DNR said is fed by groundwater from the same aquifer. Protected by state law, calcareous fens are rich in calcium and peat and so unique the DNR considers them "one of the rarest natural communities in the United States."

Enbridge has hired a consultant to study breach effects on the fen.

In the third confirmed aquifer breach, just outside the reservation of the Fond du Lac Band of Lake Superior Chippewa, groundwater flowing onto reservation land could harm the band's stands of sacred wild rice, a plant particularly sensitive to water depth, temperature and chemistry. The band has said it will have a better understanding of any impacts during the coming growing season.