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

We issue this permit to allow the use of imazamox and marker dyes on commercial clam beds (excluding geoduck) only in Willapa Bay for control of the non-native eelgrass Zostera japonica, which is a class C noxious weed.

Willlapa Bay commercial shellfish beds were historically sand/mud flats. The plant has colonized these beds, making it difficult to grow and harvest clams.

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

Permit documents

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Annual reports and pre-treatment plans

NOTE: The following information provides annual operations report information. We have recently re-developed our Water Quality permit database (PARIS). Soon, these reports will be transitioned over and available through PARIS.