The U.S. Army Corps of Engineers (the Corps) recently proposed eliminating its longstanding process and requirements for compliance with Section 106 of the National Historic Preservation Act (NHPA). The proposed rule would delete Appendix C to the Corps’ Clean Water Act permitting regulations and substitute the Advisory Council on Historic Preservation’s NHPA regulations at 36 C.F.R. Part 800, which applies across all federal agencies. Interested parties can submit comments on the proposed rule by April 9, 2024.

This proposal likely signals the Corps’ intention to broaden its Section 106 reviews to consider the effects of its undertakings on historic properties. The most significant differences between Appendix C and the Part 800 regulations are their definitions of federal activities or “undertakings” subject to Section 106 review and the scope of the review itself. Under Appendix C, an “undertaking” includes the work, structure, or discharge that requires the Corps permit, whereas the Part 800 regulations define “undertaking” more broadly to include projects, activities, or programs funded in whole or in part under the direct or indirect jurisdiction of a federal agency, including those carried out by or on behalf of a federal agency or with federal financial assistance, and those requiring a federal permit, license, or approval.

Separately, Appendix C confines the Section 106 review to the “permit area,” which consists of directly affected jurisdictional waters, including wetlands and uplands. The Supreme Court recently further limited the Corps’ jurisdiction in Sackett v. EPA. Appendix C further sets forth standards and examples for defining the permit area. The Part 800 regulations, by contrast, lack such details or limitations in identifying the undertaking’s “area of potential effects” (APE), which includes the geographic area within which the undertaking could directly or indirectly impact historic properties.

Other differences between Appendix C and the Part 800 regulations involve procedures for resolving any unavoidable adverse impacts on historic properties that result from a federal undertaking and the inclusion in the Part 800 regulations of requirements for consultation with Tribal and Native Hawaiian organizations.

The Corps bases its proposed withdrawal of Appendix C on purported confusion that has resulted from differences between its rules and the ACHP’s Part 800 regulations and supposed inconsistencies between the Corps’ review process and the processes of other federal agencies. However, the Corps has previously stated that Appendix C accurately reflects the limits of its jurisdiction over activities occurring in regulated waters, and thus, substituting the more general Part 800 rules may still result in confusion concerning the scope of the Corps’ authority for Section 106 review.