WALLA WALLA – The U.S. Army Corps of Engineers will apply herbicide in an attempt to remove reed canary grass, an invasive plant species, from Garrison and Yellowhawk creeks this Thursday and Friday.
“Reed canary grass is a highly invasive weed that has the ability to restrict waterways,” Natural Resources Specialist Jeremy Nguyen said. “If left unchecked, it could degrade fish passage, and over the past 10 years, it has narrowed the creeks significantly.”
The USACE consulted with the National Marine Fisheries Service, U.S. Fish and Wildlife and herbicide manufacturers to determine the best herbicide application for this location. The decision is to use aquatic-labeled herbicide Clearcast on the reed canary grass in an attempt to remove it from the creeks to improve flows.
According to the USACE, there is no intended impact to downstream homeowners or irrigators during or after the treatment. The label recommends irrigation intakes within 100 feet of the treatment area not be used for the day, however, there are no known intakes within 100 feet of the treatment areas.
If downstream homeowners or irrigators have concerns, they may choose not to use the water on Thursday and Friday. For more information about the herbicide application, contact the Mill Creek Project Office at 509-527-7160.