Enbridge Line 5
Great Lakes Tunnel Project Permit Application
Enbridge Energy, Limited Partnership is in the process of seeking approval to construct and operate a pipeline within a tunnel below the bottomlands of the Straits of Mackinac. Depending upon obtaining all of the necessary permits and approvals, Enbridge hopes to begin construction of the Great Lakes Tunnel in 2021, with operation of a new Line 5 segment in the Straits in 2024.
Here you can find information on the various permit applications, as well as information on how to participate in the public comment processes on the applications.
Here you can find information on the various permit applications, as well as information on how to participate in the public comment processes on the applications.
U.S. Army Corps of Engineers
Enbridge submitted an application for a Department of the Army (DA) permit. The Corps of Engineers is reviewing the proposed project under Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act.
Under Section 10 of the Rivers and Harbors Act of 1899, the Corps of Engineers regulates work or structures in, over, or under navigable waters of the United States. Under Section 404 of the Clean Water Act, the Corps of Engineers regulates discharges of dredged or fill material into waters of the United States, including wetlands.
Project Summary:
Enbridge proposes to construct an 18- to 21-foot-diameter tunnel approximately 3.6 miles long, underneath the lakebed of the Straits of Mackinac at depths at least 10 feet below the top of rock or 60 feet below the mud line, whichever is shallower. Approximately 364,000 cubic yards of material would be removed from underneath the lakebed to construct the tunnel. The material would be disposed of in an upland location. Upon tunnel completion, the applicant proposes to install a new 30-inch diameter pipeline within the tunnel, for light crude oil and natural gas liquids, to replace the existing Line 5 dual pipelines crossing the Straits of Mackinac. The tunnel would be constructed using a tunnel boring machine (TBM). Pre-cast concrete segmental lining would be installed as the tunnel is constructed, and the annular space outside the tunnel’s concrete lining would be filled with low-permeability grout.
Approximately 194 cubic yards of clean aggregate fill would be discharged into a wetland area approximately 113 feet long, 16 feet wide, and 3.7 feet deep (in wetland W3 on the attached plans), to provide access around the existing North Straits Facility to a construction and staging area to the north of the facility. After completion of construction, the fill in this 0.03-acre area would be removed, and the area would be seeded with emergent wetland seed mix.
An existing road (Boulevard Drive) would be widened to 20 feet in top width and up to 38 feet in base width, which would involve approximately 222 cubic yards of fill placed in seven wetland areas totaling 3,468 square feet (0.08 acre).
Two outfall structures for treated water would be constructed in wetland W8. Outfall 002 (as identified on the attached plans) would involve discharge of 55 cubic yards of aggregate fill in a wetland area 50 feet long, 10 feet wide, and 3 feet deep. Outfall 003 would involve discharge of 44 cubic yards of aggregate fill in a wetland area 40 feet long, 10 feet wide, and 3 feet deep. The two outfalls would involve a total of 0.02 acre of wetland fill.
Two water intake structures, each with a base approximately 10 feet by 10 feet, would be installed on each side of the Straits, located approximately 280 feet offshore the northern work area in approximately 10 feet of water depth, and located approximately 350 feet offshore the southern work area in 17 feet of water depth, with a 6- to 12-inch diameter pipe connected to on-shore water storage tanks. A discharge pipe would also be connected to the southern intake, which would be used intermittently to discharge treated water. Each intake structure would be marked with a surface buoy. The water intakes would be removed upon completion of tunnel construction.
Upon completion, the new 30-inch pipeline within the tunnel would be tied in to the upland portions of the Line 5 pipeline, and the existing Line 5 dual submerged pipelines crossing the Straits of Mackinac would be decommissioned.
Enbridge has proposed two decommissioning alternatives for the existing pipeline: 1) the pipeline would be purged, cleaned, and abandoned in place, or 2) the pipeline would be purged and cleaned, and exposed portions of the pipeline between the 65-foot depth contours would be removed. This second alternative would involve removal of all screw anchors, capping the ends of the remaining buried parts of the pipeline, using a jet sled or similar high-pressure technology to expose partially buried portions of the pipeline, cutting the pipeline in to segments, and removing it from the lakebed. Portions of the dual pipelines landward of the 65-foot depth contours are currently buried in sediment and would remain in the waterway.
Proposed project details, the public hearing notice and additional information are available at https://go.usa.gov/x79v8/.
Enbridge submitted an application for a Department of the Army (DA) permit. The Corps of Engineers is reviewing the proposed project under Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act.
Under Section 10 of the Rivers and Harbors Act of 1899, the Corps of Engineers regulates work or structures in, over, or under navigable waters of the United States. Under Section 404 of the Clean Water Act, the Corps of Engineers regulates discharges of dredged or fill material into waters of the United States, including wetlands.
Project Summary:
Enbridge proposes to construct an 18- to 21-foot-diameter tunnel approximately 3.6 miles long, underneath the lakebed of the Straits of Mackinac at depths at least 10 feet below the top of rock or 60 feet below the mud line, whichever is shallower. Approximately 364,000 cubic yards of material would be removed from underneath the lakebed to construct the tunnel. The material would be disposed of in an upland location. Upon tunnel completion, the applicant proposes to install a new 30-inch diameter pipeline within the tunnel, for light crude oil and natural gas liquids, to replace the existing Line 5 dual pipelines crossing the Straits of Mackinac. The tunnel would be constructed using a tunnel boring machine (TBM). Pre-cast concrete segmental lining would be installed as the tunnel is constructed, and the annular space outside the tunnel’s concrete lining would be filled with low-permeability grout.
Approximately 194 cubic yards of clean aggregate fill would be discharged into a wetland area approximately 113 feet long, 16 feet wide, and 3.7 feet deep (in wetland W3 on the attached plans), to provide access around the existing North Straits Facility to a construction and staging area to the north of the facility. After completion of construction, the fill in this 0.03-acre area would be removed, and the area would be seeded with emergent wetland seed mix.
An existing road (Boulevard Drive) would be widened to 20 feet in top width and up to 38 feet in base width, which would involve approximately 222 cubic yards of fill placed in seven wetland areas totaling 3,468 square feet (0.08 acre).
Two outfall structures for treated water would be constructed in wetland W8. Outfall 002 (as identified on the attached plans) would involve discharge of 55 cubic yards of aggregate fill in a wetland area 50 feet long, 10 feet wide, and 3 feet deep. Outfall 003 would involve discharge of 44 cubic yards of aggregate fill in a wetland area 40 feet long, 10 feet wide, and 3 feet deep. The two outfalls would involve a total of 0.02 acre of wetland fill.
Two water intake structures, each with a base approximately 10 feet by 10 feet, would be installed on each side of the Straits, located approximately 280 feet offshore the northern work area in approximately 10 feet of water depth, and located approximately 350 feet offshore the southern work area in 17 feet of water depth, with a 6- to 12-inch diameter pipe connected to on-shore water storage tanks. A discharge pipe would also be connected to the southern intake, which would be used intermittently to discharge treated water. Each intake structure would be marked with a surface buoy. The water intakes would be removed upon completion of tunnel construction.
Upon completion, the new 30-inch pipeline within the tunnel would be tied in to the upland portions of the Line 5 pipeline, and the existing Line 5 dual submerged pipelines crossing the Straits of Mackinac would be decommissioned.
Enbridge has proposed two decommissioning alternatives for the existing pipeline: 1) the pipeline would be purged, cleaned, and abandoned in place, or 2) the pipeline would be purged and cleaned, and exposed portions of the pipeline between the 65-foot depth contours would be removed. This second alternative would involve removal of all screw anchors, capping the ends of the remaining buried parts of the pipeline, using a jet sled or similar high-pressure technology to expose partially buried portions of the pipeline, cutting the pipeline in to segments, and removing it from the lakebed. Portions of the dual pipelines landward of the 65-foot depth contours are currently buried in sediment and would remain in the waterway.
Proposed project details, the public hearing notice and additional information are available at https://go.usa.gov/x79v8/.
State of Michigan Permits
Line 5 Enbridge Straits Tunnel Resource Permit
Application Submission Number: HNY-NHX4-FSR2Q
Enbridge has applied to the State of Michigan Department of Environment, Great Lakes, and Energy (EGLE) for a permit under authority of Part 303, Wetlands Protection, and Part 325, Great Lakes Submerged Lands.
Part 303, Wetland Protection, of the Natural Resources and Environmental Protection Act (Act 451 of 1995), requires a permit to fill, dredge, or remove soil from a wetland, construct, operate, or maintain a use in a wetland, or drain surface water from a wetland.
Part 325 Great Lakes Submerged Lands, of the Natural Resources and Environmental Protection Act (Act 451 of 1995), regulates construction activities along the Great Lakes shoreline and the over 38,000 square miles of Great Lakes bottomlands, including coastal marshes.
Application Submission Number: HNY-NHX4-FSR2Q
Enbridge has applied to the State of Michigan Department of Environment, Great Lakes, and Energy (EGLE) for a permit under authority of Part 303, Wetlands Protection, and Part 325, Great Lakes Submerged Lands.
Part 303, Wetland Protection, of the Natural Resources and Environmental Protection Act (Act 451 of 1995), requires a permit to fill, dredge, or remove soil from a wetland, construct, operate, or maintain a use in a wetland, or drain surface water from a wetland.
Part 325 Great Lakes Submerged Lands, of the Natural Resources and Environmental Protection Act (Act 451 of 1995), regulates construction activities along the Great Lakes shoreline and the over 38,000 square miles of Great Lakes bottomlands, including coastal marshes.
Summary of the Proposed Project
Enbridge is proposing an approximately 3.58 mile tunnel between Point La Barbe in Michigan’s Upper Peninsula to McGulpin Point in Michigan’s Lower Peninsula.
Tunnel Construction
An 18-to 21- foot inside diameter tunnel to be constructed using a tunnel boring machine (TBM). Construction is proposed to start on the south side, Mackinaw City. Once tunnel construction begins, construction activities are expected to occur 24 hours a day/six days a week for an estimated two years.
Construction activities on the north side are expected to average 12 hours per day, with some activities requiring 24 hours per day operation. This activity includes breaking up rock, which may be completed through drilling and blasting with explosives.
The tunnel will be constructed through rock and, in the deep channel of the Straits, through glacial deposits. The top of the tunnel will be approximately 60 feet beneath the lakebed.
Enbridge is proposing an approximately 3.58 mile tunnel between Point La Barbe in Michigan’s Upper Peninsula to McGulpin Point in Michigan’s Lower Peninsula.
Tunnel Construction
An 18-to 21- foot inside diameter tunnel to be constructed using a tunnel boring machine (TBM). Construction is proposed to start on the south side, Mackinaw City. Once tunnel construction begins, construction activities are expected to occur 24 hours a day/six days a week for an estimated two years.
Construction activities on the north side are expected to average 12 hours per day, with some activities requiring 24 hours per day operation. This activity includes breaking up rock, which may be completed through drilling and blasting with explosives.
The tunnel will be constructed through rock and, in the deep channel of the Straits, through glacial deposits. The top of the tunnel will be approximately 60 feet beneath the lakebed.
Pipeline Installation
Once the tunnel is constructed, installation of a 30-inch pipeline is proposed. (Line 5 in the Straits is currently two 20-inch pipelines) This will be done by welding of pipe joints and incremental pushing/pulling of the pipeline through the tunnel. Pipeline installation is expected to take an additional eight months.
Waste and Disposal
Waste products include surface and tunnel muck of soil and broken rock, bentonite slurry used by the tunnel boring machine. Tunnel muck and rock cuttings that can be reused will be used for fill on-site. Anything not able to be reused will be disposed of at a waste site.
Bentonite will be stockpiled on site, but there is no mention of how it will be disposed. Enbridge has applied separate for a National Pollutant Discharge Elimination System (NPDES) permit to discharge treated tunnel water back into the Great Lakes (see below).
Environmental Impacts
Once the tunnel is constructed, installation of a 30-inch pipeline is proposed. (Line 5 in the Straits is currently two 20-inch pipelines) This will be done by welding of pipe joints and incremental pushing/pulling of the pipeline through the tunnel. Pipeline installation is expected to take an additional eight months.
Waste and Disposal
Waste products include surface and tunnel muck of soil and broken rock, bentonite slurry used by the tunnel boring machine. Tunnel muck and rock cuttings that can be reused will be used for fill on-site. Anything not able to be reused will be disposed of at a waste site.
Bentonite will be stockpiled on site, but there is no mention of how it will be disposed. Enbridge has applied separate for a National Pollutant Discharge Elimination System (NPDES) permit to discharge treated tunnel water back into the Great Lakes (see below).
Environmental Impacts
- Wetlands
- Wetlands to be impacted by the project include forested wetlands and Great Lakes coastal wetlands. Proposed impacts include .03 acres of temporary impacts and .1 acre of permanent impacts, for a total of .13 acres of wetland impacts. Enbridge is not proposing mitigation for the permanent wetland impacts, but is proposing to remove invasive Phragmites from an on-site wetland.
- Threatened and Endangered Species
- Houghton’s goldenrod and dwarf lake iris, both federally listed Threatened species, are present on the north side in Mackinac County. Based on a 2019 survey, approximately 3,777 Houghton’s goldenrod plants and 7,757 dwarf lake iris plants will be impacted. Enbridge proposes to relocate 50% of these plants to mitigate for the loss.
Water Discharge Permit
National Pollutant Discharge Elimination System (NPDES) permit
Application Submission Number HNY-TBJC-PNK8V
Part 31, National Pollution Discharge Elimination Act (NPDES) – An NPDES permit is required for any discharge into the surface waters of the State.
Enbridge is proposing to withdraw water from the Straits to use to excavate material out of the tunnel in the form of a slurry (a mixture of solids and liquid). The water for use during the construction process is up to 1.99 million gallons a day on the north side from the Straits, and up to 1.99 million gallons per day on the south side from the Straits.
The slurry will be treated for solids removal, with a portion - bentonite – reused in the tunneling process, and the remainder sent to a settling pond. Water from the pond would be treated to meet water quality standards and then discharged into Lake Michigan. In addition, stormwater and groundwater that infiltrates into the shaft and tunnel will be captured and handled in a manner that treats contaminants before being discharged into the Straits. It is anticipated that approximately 1,500 gallons per day could be generated on the north side, and approximately 15,000 gallons per day on the south side.
Michigan Public Service Commission Case No. U-20763
On April 17, 2020, Enbridge Energy, Limited Partnership filed an application with the Michigan Public Service Commission (MPSC or Commission) pursuant to Public Act 16 of 1929, MCL 483.1 et seq, also referred to as Act 16, requesting authority to replace and relocate the segment of Line 5 crossing the Straits of Mackinac into a tunnel beneath the Straits of Mackinac.
Siting authority for crude oil and petroleum product pipeline siting is granted to the MPSC pursuant to Act 16. Approval under Act 16 allows the applicant to construct the pipeline as specified in the Commission order and subject to any other governmental permits that are required.
The Act 16 application is reviewed as part of a formal hearing process, known as a contested case, 2 that takes approximately one year for a Commission decision. This process includes expert witness testimony with cross examination by legal counsel representing parties to the case.
