Nationwide Permit 48 authorizes structures, work, and discharges of dredged or fill material necessary for both new and continuing commercial shellfish mariculture operations. This includes the cultivation of bivalve molluscs such as oysters, mussels, clams, and scallops within authorized project areas. The permit covers the installation of buoys, floats, racks, trays, nets, and other structures required for the growth and harvesting of shellfish. The scope of this permit is limited to activities that result in no more than minimal individual and cumulative adverse environmental effects. It does not authorize the cultivation of non-indigenous species unless those species have been previously cultivated in the waterbody, nor does it authorize the construction of attendant features like land-based processing facilities, which would require separate permits.
The 2026 reissuance of NWP 48 maintains the same national terms and conditions as the 2021 version, following a period where the permit was extensively litigated and subsequently revised. The Corps determined that the existing qualitative and quantitative limits, including the 1/2-acre notification threshold for new activities, remain appropriate for ensuring minimal environmental impact. Updates were made to the supporting decision document to reflect current environmental baseline data, including findings from the 2022 National Lakes Assessment and the 2021 National Wetland Condition Assessment. The Corps also clarified that the permit is intended to provide a predictable regulatory pathway for the mariculture industry while maintaining protections for submerged aquatic vegetation and other sensitive marine resources.
Commercial shellfish farmers, mariculture companies, and aquaculture consultants use this permit. It is the primary regulatory authorization for anyone cultivating oysters, clams, or other bivalves in navigable waters that requires the placement of gear or minor discharges of fill.
The Corps determined that the reissuance of NWP 48 results in 'no effect' on federally listed endangered or threatened species or their critical habitat. This finding is supported by General Condition 18, which requires that no activity 'may affect' listed resources unless project-specific ESA Section 7 consultation has been completed. District engineers also verify Essential Fish Habitat (EFH) compliance, often utilizing regional programmatic consultations to streamline reviews for mariculture operations. Compliance with Section 106 of the National Historic Preservation Act is ensured through General Condition 20. For any activity that has the potential to cause effects on historic properties, the permittee must submit a pre-construction notification, allowing the district engineer to complete the necessary review and consultation before granting authorization.
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