In Ohio Valley Environmental v. Bulen, the Fourth Circuit using Chevron deference held that the Army Corps of Engineers complied with the Clean Water Act when it promulgated NWP 21. NWP 21 is a general permit for the discharge of dredged or fill material into the waters of the United States that allows projects to proceed only after receiving individualized authorization from the Corps. According to the court:
We conclude that the Corps complied with section 404(e) when it issued NWP 21. The Corps identified a category of activities, it determined that those activities would have a minimal environmental impact both separately and cumulatively, and it provided notice and opportunity for public hearing before issuing the permit. The Corps' issuance of NWP 21 thus fell within its authority under section 404(e).