Zostera japonica Management on Commercial Clam Beds in Willapa Bay General Permit
The Zostera japonica Management on Commercial Clam Beds in Willapa Bay permit is a combined National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit. It allows the use of imazamox and marker dyes on commercial clam beds (excluding geoduck), in Willapa Bay only, for control of Zostera japonica eelgrass, a Class C noxious weed.
Proposed permit modification
Based on new scientific research and data, we are updating an existing, active water quality permit that allows commercial shellfish growers to continue to use the herbicide imazamox to control non-native eel grass in Willapa Bay. The growers requested the permit from Ecology several years ago because the non-native eel grass, Zostera japonica, is a noxious weed that makes it difficult to grow and harvest clams.
When we issued the permit in 2014, we required the growers to study and verify that a 10-meter unsprayed buffer around the treatment area adequately protects native eelgrass and water quality. The scientific research and results came back showing that the application method is working as intended and confines the herbicide impact to the applied area. We have updated the permit based on the new data. Scientists from the National Oceanic and Atmospheric Administration, and state departments of Fish & Wildlife and Natural Resources reviewed the study data and did not recommend changes to the buffer. According to the U.S. Environmental Protection Agency, imazamox is practically non-toxic for mammals, fish, birds and invertebrates. EPA does not believe it poses a hazard to public health in or on food products. This permit is specifically tailored for commercial clam beds, and we reiterate, it’s for use in Willapa Bay only.-close-
Submitting written comments
The public comment period ended 5:00 pm, March 7, 2017. We are reviewing comments received.
Workshop and Public Hearing
We held workshops and public hearings on these dates and locations:
Current Permit Documents
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