Enbridge Line 3 pipeline replacement project

Enbridge Energy is continuing restoration work around its new Line 3 crude oil pipeline across Minnesota. The new line replaces an aging Line 3 and began operating in October 2021, after Enbridge completed the project’s construction phase. 

Our role

Enbridge needed multiple approvals, permits, and certifications from state agencies, including the Minnesota Pollution Control Agency, to construct the pipeline. Because Enbridge proposed to alter protected wetlands for the Line 3 project by either filing or excavating areas of the wetlands, the company applied for a permit under Section 404 of the federal Clean Water Act (CWA), governing placement of dredged or fill material into wetlands. Section 404 permits are issued by the U.S. Army Corps of Engineers.

The 404 permit requires the applicant to also request a water quality certification from the state under CWA Section 401. This allows the state (in this case the MPCA) to review the proposed activity to determine whether it complies with applicable water quality standards, and to identify any additional conditions needed to ensure compliance.

On November 12, 2020, the MPCA granted final 401 water quality certification for Enbridge’s Line 3 replacement project — the agency’s most stringent water quality certification issued. The certification required Enbridge to take every precaution to safeguard 730 acres of wetlands and more than 200 streams in northern Minnesota. The MPCA reached its final decisions after comprehensive regulatory and technical analysis, extensive public participation, a contested case hearing that investigated the project’s water quality protections, and coordination with other state/federal agencies. On November 23, 2020, the U.S. Army Corps of Engineers issued the federal 404 permit.

Project information

The new Enbridge Line 3 pipeline follows the previous pipeline from North Dakota to the Clearbrook Terminal in Clearwater County, Minnesota. From the Clearbrook Terminal eastward, the pipeline was constructed in a new right-of-way, south of the existing Line 3, ending at an existing terminal in Superior, Wisconsin. The existing Line 3 pipeline was permanently deactivated and will remain in place.

The purpose of the replacement project was to address pipeline integrity and safety concerns related to the previous pipeline and to restore the throughput of the line to its original operating capacity of 760,000 barrels per day.

Next steps and timeline

While the pipeline began operating once construction was completed in 2021, the project remains open as Enbridge works to ensure the site is returned to its condition before construction. The old pipeline, while no longer in use, remains in place. Decisions and permits related to decommissioning the old line will include numerous landowners and require permits from state and federal agencies. The process and its timing has yet to be determined.