Traverse City, Mich. — On December 5, Flow Water Advocates (Flow), a Great Lakes water protection organization, in partnership with the Sierra Club and Surfrider Foundation (known collectively as the Water Coalition), submitted written comments on the U.S. Army Corps of Engineers’ Supplemental Draft Environmental Impact Statement (Supplemental DEIS) for Enbridge’s proposed Line 5 tunnel project, which is now considering an alternative to the tunnel proposal using Horizontal Directional Drilling (HDD) to create a borehole and install a replacement pipeline under the Straits of Mackinac (the HDD Installation Alternative).
Support Flow’s work to defend the Great Lakes.
Enbridge’s application for the proposed project’s federal Clean Water Act and Rivers and Harbors Act permits is currently under review by the U.S. Army Corps of Engineers (the Corps). The National Environmental Protection Act (NEPA) requires agency and public review, including the preparation of both a Draft and Final Environmental Impact Statement (and supplements, when warranted), which must assess the purpose and need for the proposed project, alternatives to the proposal, and an assessment of the environmental consequences of the project.
While the Corps originally discounted the HDD Installation Alternative as infeasible years ago, the Supplemental DEIS states that Enbridge submitted information that pursuing the alternative is now technically feasible due to advances in technology, and that the Corps subsequently determined that the HDD Installation Alternative should be subject to “detailed analysis” in the EIS.
The Water Coalition’s comments emphasize that the Corps’ unjustified fast-tracking of the review process for both the DEIS and the Supplemental DEIS unlawfully undermines public participation in the process, as well as the “hard look” required by the agency under NEPA. The comments also highlight the Supplemental DEIS’ striking failure to include the information necessary for the agency to properly review the HDD Installation Alternative and its potential impacts on the surrounding lands and waters. Among the deficits are a failure to detail impacted wetlands, confirm the stability of the bedrock, and survey for protected species and archeological resources.
In order to comprehensively compare the potential environmental impacts of the HDD Installation Alternative against Enbridge’s preferred tunnel project, the Corps and the public must have sufficient location-specific data and information about the risks posed by each technology, as well as the site-specific impacts of each method. The Corps attempts to justify these deficiencies in the Supplemental DEIS by deferring the required assessment to a potential future in which Enbridge chooses to pursue the HDD alternative. However, this reasoning hampers the evaluation of alternatives, and is unacceptable under federal law.
The comments conclude that the supplemental review does not remedy the fatal flaws of the May 2025 DEIS, outlined in the Water Coalition’s June 2025 comments, but rather compounds them.
The people of the Great Lakes Basin depend on the Corps, with its technical expertise and mandate to serve the public interest, to take great care in its consideration of the potential significant environmental impacts of the proposed tunnel and alternatives. The Corps violates that mandate in both the May 2025 DEIS and the new Supplemental DEIS, by failing to collect the information necessary to properly assess the risks, and by unlawfully failing to consider feasible alternatives to building a new pipeline through the Straits. Flow and its partners remain steadfast in their commitment to hold the Corps accountable to its legal obligations.
The Corps anticipates that it will publish a Final EIS in early 2026, followed by a Record of Decision in the Spring.
###
Flow Water Advocates is an independent 501(c)(3) nonprofit organization based in Traverse City, Michigan. Our mission is to ensure the waters of the Great Lakes Basin are healthy, public, and protected for all. With a staff of legal and policy experts, strategic communicators, and community builders, Flow is a trusted resource for Great Lakes advocates. We help communities, businesses, agencies, and governments make informed policy decisions and protect public trust rights to water. Learn more at www.FlowWaterAdvocates.org.
