Nationwide Permit 31 authorizes discharges of dredged or fill material into waters of the United States and structures or work in navigable waters associated with the maintenance of existing flood control facilities. This includes the removal of accumulated sediment and debris from facilities such as debris basins, retention or detention basins, levees, and channels. To qualify, the facility must have been previously authorized by the Corps or constructed by the Corps and transferred to a non-Federal sponsor for operation and maintenance. The permit is designed to allow for the restoration of a flood control facility to its previously established 'maintenance baseline.' This baseline is defined by the physical characteristics (such as dimensions, configuration, and design capacity) of the facility as originally authorized. Maintenance is limited to the minimum necessary to restore this baseline, and the permit does not authorize the expansion of a facility beyond its original design. Authorized work includes the disposal of dredged material into authorized disposal sites, provided those sites are in waters of the United States and the discharge is authorized by a separate permit. It also covers temporary structures and fills needed to conduct the maintenance, such as dewatering construction sites, provided the areas are restored to pre-construction elevations upon completion.
The 2026 reissuance of NWP 31 contains no substantive changes to its terms or conditions compared to the 2021 version. The Corps reevaluated the permit's quantitative and qualitative limits and determined that the existing framework remains effective in ensuring that authorized maintenance activities result in no more than minimal individual and cumulative adverse environmental effects. While the permit text remains identical to the previous version, the supporting decision document was updated with the latest environmental baseline data. This includes current information from national assessments like the 2022 National Lakes Assessment and the 2021 National Wetland Condition Assessment to ensure the environmental review is grounded in the most current available scientific data.
Public works departments, flood control districts, and non-Federal sponsors of Corps-constructed projects typically use this permit. It is the primary vehicle for compliance managers overseeing the periodic removal of sediment and debris from authorized flood management infrastructure like levees and detention basins.
The Corps determined that the reissuance of NWP 31 results in a 'no effect' finding for federally-listed endangered or threatened species and designated critical habitat. This is based on General Condition 18, which requires project-specific ESA Section 7 consultation if an activity '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. Because NWP 31 requires a mandatory Pre-Construction Notification (PCN), district engineers have the opportunity to review every proposal for potential impacts on historic properties before work begins. Essential Fish Habitat (EFH) is also evaluated during the PCN review, and district engineers may add regional or activity-specific conditions to ensure no more than minimal adverse effects on sensitive aquatic environments.
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