As of today (4/16/19), the plan is for 24-hour notices to be posted on the 23^rd. The weed treatment itself will take place on the 24^th and will require only one day of work. Of course, this schedule can change if the weather becomes disagreeable, but predictions are solidly favorable for now.

Water-Rights Holders and Residents Received 14-Day Notices.

AquaTechnex, the treatment applicator, mailed a notice to all water-rights holders within a quarter mile of the planned treatment last week. They directed the certified mail to the addresses on record with Kootenai County and the Department of Environmental Quality. AquaTechnex also posted notices on doors of any shoreline homes within a quarter mile of the treatment. And, finally, Honeysuckle and Sportsman’s Access boat launches, have signs posted for non-resident folk who might be entering the water on the treatment day.

Download the notices from ISDA’s Invasive Species website where you can also view a treatment map and stay up-to-date on ISDA’s plans for treatment of Hayden Lake:

• Treatment Map
• 14 Day Shoreline Resident Notice
• 14 Day Water Right Notice

Fluridone Has Fewer Water-Use Restrictions.

There are many differences between the contact-herbicide, Diquat, used in the past for Eurasian Watermilfoil treatment, and this year’s chemical, Fluridone. Let’s start with the most immediate: water-use restrictions – or lack of. Water-use restrictions at the applied concentrations of Fluridone are not as disruptive as they were for Diquat. Quoting directly from the applicator’s notice:

• Recreation: There are no swimming or fishing restrictions in the treatment area for this product.
• Domestic Water Use: Water from the treatment area, or water intakes from within 600 feet of the treatment area, can be used for domestic or potable water purpose without restriction.
• Irrigation Water Use: Irrigation water drawn from the treatment area has the following use restrictions, which vary depending on crop or end use:
  • You may water established tree crops seven days after completion of each application.
  • You may water established row crops/turf/plants seven days after each of the three applications.
  • Do not water newly seeded crops/seedbeds or areas to be planted including over-seeded golf course greens until a water sample test indicates that herbicide levels are below five parts per billion.
  • Water samples will be collected 2-3 weeks after each treatment interval, with results published on this [the applicator’s] website and the ISDA invasive species website (invasivespecies.idaho.gov)

Plants Affected by Fluridone Will Take Weeks to Die.

Another critical difference is how this chemical does its job. Diquat is a surface-herbicide. It broke down the cell membranes that it touched and killed the plant within hours or days. Curly-leaf will absorb the Fluridone, and it will work from within the plant cells to disrupt photosynthesis. This translates to a longer transition time requiring prolonged contact between the plants and the herbicide. In fact, the applicator will apply Fluridone three times at three-week intervals. This process will maintain a sufficient concentration for the desired effect.

They will test the chemical concentration one-to-two weeks after each application. Test results will help to ensure that movement of water in the system doesn’t raise the concentration toward an unacceptable level, nor decrease it to an ineffective level. Water testing on about May 8^th will follow this first treatment on April 24^th.  ISDA will share results as soon as they are available via their website.

Applicator Will Post 24-hour Notice on April 23.

Stay tuned for a 24-hour notice which the applicator will post on docks and at public access points. Snap a photo and send it back to me or share it on our Facebook page. If you live in a lake-side neighborhood that has a central access point, help keep your neighbors and visitors up-to-date. Print and display the 24-hour notice, (I’ll share it here) where anyone who enters your neighborhood can see it.

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