NWP 46: Discharges in Ditches

Discharges of dredged or fill material into non-tidal ditches that are (1) constructed in uplands, (2) receive water from an area determined to be a water of the United States prior to the construction of the ditch, (3) divert water to an area determined to be a water of the United States prior to the construction of the ditch, and (4) determined to be waters of the United States.

Acreage limit

Permanent loss of waters of the United States authorised under NWP 46 cannot exceed 1 acre per single and complete project.

Loss limit is one acre of waters of the United States.

Pre-construction notification: Always required

Every use of NWP 46 requires a pre-construction notification to the district engineer before work begins. There is no minimum-impact threshold that exempts a project from this requirement.

If a PCN is required, general condition 32 gives the district engineer 30 calendar days to determine whether it is complete, then up to 45 calendar days from receipt of the complete PCN to respond before the permittee may proceed. Those are two separate clocks, not one.

Source

Federal Register citation: 91 FR 768
Effective date: March 15, 2026
Cited text: 91 FR 768 - Reissuance and Modification of Nationwide Permits (final rule, 8 Jan 2026) Read the rule

What this page does not tell you

District regional conditions. Any of the 38 USACE districts can narrow NWP 46, add a notification requirement beyond general condition 32, or revoke the permit entirely inside its boundaries. PermitBird holds no compiled regional conditions yet. Check the district.
State Clean Water Act Section 401 certification. Each of the 54 states and territories must certify, condition, waive or deny use of this permit before it authorises a discharge there. PermitBird holds no compiled certification yet. Check the state.