Enbridge Energy's pathway for a new pipeline to replace its aging "Line 3" across northern Minnesota would likely cause more wildlife habitat loss and have more impact on wild rice lakes than any of four alternative routes being looked at by state regulators.

But impacts on fish and wildlife would vary only slightly between the routes. And environmental and cultural resources would be hurt less by a spill on Enbridge's proposed new Line 3 route than in a spill on two alternative routes that run parallel to the current Line 3, according to a state environmental assessment released Monday.

The report is a big development in Enbridge's 2 ½-year quest to replace a corroding, 1960s-vintage pipeline. The company wants to build a 337-mile pipeline that would follow Line 3's current route to Clearbrook, but would then jog toward Park Rapids through an area known for pristine waters and wild rice lakes.

The draft environmental impact statement (EIS) released Monday by the Minnesota Department of Commerce offers comparisons between alternative pipeline routes, but makes no recommendations on the $2.1 billion project. The report opens a public comment period through July 10, which will include 22 public meetings in counties that could be home to a new Line 3. A final EIS will then be issued.

"Enbridge looks forward to the next step for this important system modernization project and advancing the regulatory process," John Swanson, Enbridge's vice president of major projects, said in a statement.

Along with the final EIS, an administrative law judge will vet the positions of Line 3 opponents and proponents and produce a critical report. The Minnesota Public Utilities Commission will then decide on the pipeline's fate, probably in mid- to late 2018.

If the new Line 3 is approved, Enbridge expects to start construction by late 2018, with an anticipated completion date in the latter part of 2019.

Environmental and American Indian groups have opposed the new Line 3, while Calgary-based Enbridge says it's needed to replace a pipeline that requires extensive maintenance and is limited to running at only 51 percent of capacity. The pipeline carries crude oil from Alberta to an Enbridge terminal in Superior, Wis., and points beyond.

Joseph Plummer, an attorney for the White Earth Band, said the tribe opposes Enbridge's proposed route and all of the alternatives. Any new Line 3 route should be the "farthest away from lake country."

The Commerce Department report compares Enbridge's preferred route with four alternatives chosen over the last few years by state agencies and through public meetings. One alternative runs south of the current pipeline; one runs north; two run along Enbridge's existing pipeline corridor.

The northerly route would have the least effect on environmental and cultural resources if an oil spill occurs; the southerly, the second least, followed by Enbridge's preferred route, the report said. The difference between those three are "relatively" small.

The two alternatives along Enbridge's existing Line 3 route carry higher risks of environmental, cultural or economic damage, according to the draft EIS. Enbridge, North America's largest pipeline operator, runs six pipelines on the same corridor across northern Minnesota, including Line 3. Together, they move at least 2.5 million barrels of oil per day.

For over 70 percent of its trip through the state, Enbridge's proposed Line 3 would run along existing rights of way, either for Enbridge's own pipeline, another company's pipeline or high-voltage power lines.

The 1,000-plus page draft EIS considered many environmental factors, including water quality, climate change and the loss of wildlife habitat from constructing and operating a new Line 3.

The draft EIS also considered "environmental justice," which it defines as fair treatment and meaningful involvement for people — "regardless of race, color, national origin or income." However, the report says it's not possible to determine which route is best from this perspective.

"Any of the routes selected between North Dakota and Superior, Wis., would … have a disproportionate and adverse effect on tribal resources and tribal members, even if the route does not cross near residences," the draft EIS said.

All routes studied in the EIS cross wild rice lakes, with Enbridge's proposed Line 3 impacting about 17 of them, the most of any route. "Wild rice is a sacred plant for American Indian tribes," the draft EIS said.

Enbridge announced in 2014 that it planned to replace Line 3, which has "corroded and cracked," according to the draft EIS. Also, the pipeline uses a coating that while popular when it was built, now tends to peel. Enbridge has been operating Line 3 since 2008 at 390,000 barrels per day. With a new Line 3, Enbridge would again move 760,000 barrels per day, the capacity of the current line.

The Line 3 replacement was originally supposed to run on Enbridge's proposed new route along with a separate $2.6 billion pipeline called Sandpiper. Enbridge planned to move North Dakota crude oil on Sandpiper to Superior and points beyond.

However, after being mired in the regulatory process for 2 1/2 years, Enbridge in September abandoned plans for the controversial Sandpiper project. Instead, it partnered with Marathon Petroleum in buying a $1.5 billion stake in a pipeline system that includes the Dakota Access, which takes crude out of North Dakota.

Environmentalists and American Indian groups had criticized Sandpiper for the same reasons as the Line 3 replacement pipeline.

Mike Hughlett • 612-673-7003