Nationwide Permit 23 authorizes activities undertaken, assisted, authorized, regulated, funded, or financed, in whole or in part, by another Federal agency or department where that agency has determined the activity is a "categorical exclusion" under the National Environmental Policy Act (NEPA). To qualify, the Office of the Chief of Engineers must concur that the specific categorical exclusion (CE) results in no more than minimal individual and cumulative adverse environmental effects. The scope of this permit covers both Section 10 navigable waters and Section 404 discharges of dredged or fill material. It is designed to reduce regulatory duplication by allowing the Corps to leverage environmental reviews already conducted by other Federal agencies while ensuring that the authorized activities meet the statutory requirements of the Clean Water Act.
The 2026 reissuance of NWP 23 includes no substantive changes to the terms or conditions from the 2021 version. The Corps reevaluated the permit's individual and cumulative effects and determined that the existing qualitative and quantitative limits remain sufficient to ensure that authorized activities result in no more than minimal adverse environmental impacts. While the permit text remains unchanged, the supporting decision document was updated with the most recent environmental baseline data. This includes results from newer national assessments such as the 2022 National Lakes Assessment and the 2021 National Wetland Condition Assessment, ensuring that the environmental review remains current.
Federal agencies or departments, and project proponents receiving Federal funding or authorizations, use this permit for activities that are already categorically excluded under the lead agency's NEPA procedures. It is commonly used for infrastructure projects funded by agencies such as the Federal Highway Administration or the Natural Resources Conservation Service.
The Corps determined that the reissuance of NWP 23 results in "no effect" on federally-listed endangered or threatened species or their critical habitat. This is because general condition 18 requires project-specific ESA Section 7 consultation for any activity that "might affect" listed resources; no activity is authorized until that process is complete. Compliance with Section 106 of the National Historic Preservation Act is managed through general condition 20, which triggers mandatory Pre-Construction Notification (PCN) if an activity has the potential to affect historic properties. For Essential Fish Habitat (EFH), district engineers can apply regional or project-specific conditions to ensure authorized activities do not cause more than minimal individual or cumulative adverse effects.
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