Attachment 4 2026NWPs WY 401WQC

December 16, 2025

SENT VIA EMAIL

Nathan Morey
U.S. Army Corps of Engineers
Omaha District
Wyoming Regulatory Office
[email protected]
RE: Clean Water Act Section 401 Water Quality Certification of the U.S. Army Corps of Engineers 2026 Nationwide Permits in Wyoming
Dear Mr. Morey:
Please find enclosed the water quality certification decisions and response to comments consistent with Section 401 of the Clean Water Act (CWA) for the reissuance of the Nationwide Permits (NWP). On June 18, 2025, the U.S. Environmental Protection Agency, Region 8 received the U.S. Army Corps of Engineers’ requests for water quality certification under CWA Section 401 for the proposed 2026 NWPs. The EPA reviewed the June 18, 2025, Federal Register 1 notice announcing the reissuance of the NWPs, along with the regional conditions proposed by the Omaha District for Wyoming. The enclosed CWA section 401 water quality certification decision applies where the EPA is the certifying authority and includes Indian country 2 lands within the state of Wyoming3 and lands of exclusive federal jurisdiction in relevant respects within the state of Wyoming. 4

See 90 FR 26100 (June 18, 2025).
Indian country is defined at 18 U.S.C. § 1151.
Indian country in Wyoming generally includes any lands within the exterior boundaries of the Wind River Indian Reservation (subject to Wyoming v. EPA, 875 F.3d 505 (10th Cir. 2017), cert. denied, 138 S. Ct. 2677 (2018)); any land held in trust by the United States for an Indian tribe; and any other areas that are “Indian country” within the meaning of 18 U.S.C. § 1151. The enclosed CWA Section 401 certification document specifies where these decisions apply. An inventory report compiled by the U.S. General Services Administration for federal properties as of 1962 identifies properties that may contain exclusive federal jurisdiction. This document is accessible at https://www.congress.gov/116/meeting/house/110088/documents/HHRG-116-II13-20191017-SD044.pdf. The EPA notes that this inventory report is not all-inclusive and that the information contained within it has not been recently confirmed and/or updated. Please contact EPA Region 8 at [email protected] with questions regarding the jurisdictions where this certification decision applies.

Please provide this certification to any project proponent (or their designated agent) contacting the Corps regarding applicable projects that may be authorized under the 2026 NWPs. If a project proposal