US Army Corps of Engineers
St. Paul District Website

Enbridge Line 3

Project summary

Enbridge Inc. has submitted a permit application for activities affecting water resources associated with the proposed construction of the Line 3 replacement crude oil pipeline across Minnesota, and a nearly one-mile segment in North Dakota. The Corps of Engineers is evaluating the application for (1) construction-related impacts to wetlands, specifically the discharge of dredged or fill material into waters of the U.S.; (2) work in, over or under navigable waters; and (3) crossings of federal projects.

(More on regulatory authority at the bottom of this page).

(1) Construction of the pipeline would temporarily impact approximately 1,050 acres of wetlands, and permanently impact 9 acres; if authorized Enbridge would restore all temporarily-affected wetlands to pre-construction conditions and mitigate for permanent impacts

(2) The project proposes crossing 218 water bodies, three of which are considered navigable waters

(3) There is a single request to alter the Lost River Flood Control Project, a channel clearing and snagging project, located in Red Lake County, Minnesota

USACE does not regulate the overall construction or operation of pipelines, nor does it regulate the siting of any type of pipeline/utility line or any substance being transported within a pipeline.


The existing Enbridge Line 3 crude oil pipeline was constructed in phases between 1962 and 1968. It is 34 inches in diameter and 1,097 miles long, and extends from Alberta, Canada, to Superior, Wisconsin. It is proposed for replacement due to its age and integrity issues. The section of Line 3 which is the subject of this Section 10/404 application and 408 request includes the replacement of approximately 282 miles of the existing Line 3 pipeline with 330 miles of new 36-inch diameter pipeline and associated facilities from the Red River valve in North Dakota to the Minnesota/Wisconsin border.

Project impacts to aquatic resources

Construction of the project in Minnesota would require crossing 218 water bodies and result in temporary impacts and permanent wetland-type conversions to approximately 1,050 acres of wetlands. Approximately 9 acres of wetlands would be permanently impacted to construct new above-ground pump stations and valves. In addition, construction associated with nearly one-mile of the pipeline would impact wetlands adjacent to the Red River in North Dakota.

Cultural resources

Beginning in 2015 the Corps of Engineers has been working and consulting with interested tribes to gather feedback on the project and identify potential historic properties and cultural resources in the project area. A tribal cultural survey of the project corridor was completed, and elder interviews were conducted. Moving forward, discussion and review of the tribal survey and interview efforts will occur during recurring conference calls and meetings. Following coordination and consultation with tribes, coordination will be submitted to the relevant State Historic Preservation Offices.

Proposed location 

Enbridge’s designated route generally follows existing utility line corridors across 13 counties in Minnesota and an additional three-quarters mile portion of Pembina County in North Dakota. From the North Dakota/Minnesota border in Kittson County, it follows the existing Line 3 pipeline corridor to the Clearbrook Terminal in Clearwater County. Next, the route turns south from Clearbrook to generally follow an existing third-party crude oil pipeline right-of-way south to Hubbard County. The designated route then turns east to generally follow other existing electric transmission lines until it rejoins the Enbridge Mainline System right-of-way in St. Louis County, through the Fond du Lac Reservation, to the Minnesota/Wisconsin border in Carlton County

Regulatory authority

The Corps has regulatory authority under Section 404 of the Clean Water Act, and Sections 10 and 14 (Section 408) of the Rivers and Harbors Act. The Corps of Engineers does not have control over the entire pipeline and is one of several permitting agencies to review the project; no federal agency has congressional authority to regulate construction of oil pipelines.

The St. Paul District is evaluating the proposed pipeline replacement project to comply with Section 10/404 for work in waters of the U.S. associated with the applicant's designated route, in addition to reviewing a Section 408 request to alter a federal project at the proposed crossing of the Lost River in Red Lake County, Minnesota.

  • The Corps of Engineers regulates any work or structures in, over, or under navigable waters of the United States under Section 10 of the Rivers and Harbors Act of 1899.
  • The Corps of Engineers regulates discharges of dredged or fill material into waters of the United States, including wetlands, under Section 404 of the Clean Water Act.
  • If a proposed pipeline crosses federally-authorized civil works projects, the Corps of Engineers may give permission for any alteration or occupation of certain public works under Section 14 of the Rivers and Harbors Act (33 U.S. Code 408), also referred to as Section 408, when such occupation or use is not injurious to the public interest and will not impair the usefulness of the federally-authorized project.

Project location

Project overview mapproposed replacement pipeline location 

(click image or here for full-size graphic)

Contact information

U.S. Army Corps of Engineers
St. Paul District, Regulatory Branch
180 5th Street E, Suite 700
Saint Paul, MN 55101


Related sites

Minnesota Public Utilities Commission

(calendar, interactive project map, full summary)

(documents to include environmental impact statement)