Chemical Treatment Schedule
Roza Irrigation District will be continuing its aquatic weed treatment program to control aquatic plants and algae in our irrigation conveyance system. The District will be applying aquatic herbicide chemicals under a Department of Ecology NPDES and SWD General Permit. Please refer to the District's website on the products being applied and their label usage requirements.
If you use your irrigation water for fish rearing, you are advised to discontinue using the irrigation water, beginning on the day of the treatment and for at least three days thereafter.
Aquatic herbicide chemicals will be applied by licensed Roza personnel. The Roza main office can be reached at (509)837-5141 if there are any questions.
The Washington State Department of Ecology contact is the Central Regional office at 1250 Alder Street in Union Gap, WA 98903 and can be reached at (509)575-2490.
Upcoming Treatments
Treatment Date: July 8, 2026
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Past Treatments
Treatment Date: July 7, 2026
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Treatment Date: June 16, 2026
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Treatment Date: June 10, 2026
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Treatment Date: June 9, 2026
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Treatment Date: May 19, 2026
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Treatment Date: May 13, 2026
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Treatment Date: May 5, 2026
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Treatment Date: September 4, 2025
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Treatment Date: September 2, 2025
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