Corps to treat river for invasive plant
By Terry Murry on Thursday, July 6th, 2023 in Columbia Basin News More Top Stories
WALLA WALLA – The U.S. Army Corps of Engineers Walla Walla District will be performing up to five separate five-acre treatments in the Columbia River near the Tri-Cities with the herbicide diquat dibromide at an application rate of two gallons per surface acre. This effort is to control the invasive aquatic plant species flowering rush.
The work is expected to begin between July 16 and 20 and may continue through Sept. 1 if necessary. There are no fishing or swimming restrictions for the area of treated water after the herbicide application, however animals should not consume water from the area of treated water for 24 hours after application.
Additionally, there is a three-day restriction on using the water from the area of treatment for drinking or irrigating landscape and a five-day restriction on irrigating food crops. The corps will post notices on the shorelines of areas being treated 48 hours prior to treatment.
According to the Columbia Basin Cooperative Weed Management Area, flowering rush is now widely naturalized in wetlands, lakes, ditches, and slow-moving rivers in 21 states and eight provinces surrounding the USA/Canada border, and is continuing to expand outward. It displaces native plant species, impedes water flow, alters habitat structure and nutrient cycling, damages fishing, hunting, boating, and other recreational sectors, and is difficult to control.
Photo from the Washington Noxious Weed Control Bureau
