Zostera japonica management on commercial clam beds in Willapa Bay General Permit

We issue coverage under this general permit when shellfish growers choose to use an herbicide (imazamox) to control the non-native eelgrass Zostera japonica on their commercial clam beds. Zostera japonica is a class C noxious weed that may be controlled on commercial clam beds, but does not include use for control on geoduck and oyster beds. Physical and mechanical methods of Zostera japonica control are not regulated by this permit. Find out more about the Zostera japonica permit.

This permit is a combined National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit. 

The current permit went into effect April 4, 2020 and expires on March 3, 2025.

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Current permit and related documents

How we got to the current permit

We accepted comments on the draft Zostera japonica Management on Commercial Clam Beds in Willapa Bay General Permit from Sept.18, 2019 to Nov. 4, 2019​. Our response to comments includes our responses to the comments we received and describes any changes we made to the permit based on the comments. You can also read the comments we received online.

Workshops and hearings

We hosted two workshops (one as an online webinar) immediately followed by public hearings. During the workshops, we explained changes proposed and answered questions. The public hearings ended when all individuals who wanted to provided their oral testimony.