Aquatechnex Treatment Information
Last week’s aquatic herbicide treatments at Bear Creek and Priest Lake Marina were performed with liqud triclopyr. There are restrictions placed on water use for potable and irrigation uses until levels are below labeled levels within the treatment area.
The Idaho Department of Agriculture has sampled these treatment sites and the herbicide levels have dropped to the point where water use restrictions have been removed.
Aquatechnex will be assisting the Idaho State Department of Agriculture target Eurasian Milfoil in Priest Lake this week.
Our biologists plan to treat two locations in the lake that have experienced Eurasian Milfoil Growth in the past and continue to have some plants present at a level higher than can be addressed with divers. We will be applying Ecotriclopyr to portions of Bear Creek and to a marina on the West side of the lake. The application is planned for the afternoon and evening of Wednesday August 24 weather permitting.
As Priest Lake is a large water body, wind driven water currents can be a factor in maintaining contact of the herbicide with the target weed communities. As such, we target portions of the day for treatment when wind conditions are very low. If there are issues, the treatment may be delayed.
There is an irrigation restriction for those that might draw water from the treatment area. The State will be sampling this and will let us know with the levels are below those the label requires be met. We will post additional articles here this week as the treatment progresses.
The Idaho State Department of Agriculture has asked our firm to conduct Eurasian Milfoil treatments on Priest Lake in August of this year. The target dates will be the week of August 22 with the fall back dates of the week of August 29th.
We will be treating portions of Bear Creek Bay where some Eurasian Milfoil plants have remained, and we will be treating one marina area. The exact treatment dates and treatment maps will be posted near the end of next week as the weather forecasts become available.
Weather is a key consideration on this project. A very large lake such as this where the prevailing winds push from the south over the 40 mile length of the lake can move considerable amounts of water. As the winds die off, water pushed to the north flows back. In smaller lake systems this is generally not an issue or noticeable, but in this case we have noted extreme currents following wind events even when conditions were flat calm. This can affect the herbicide application if treated water is pushed out of the treatment areas and contact time is limited.
As we did last year, we will be using weather conditions as one of the key parameters in setting the application date and time. So check back often.
ISDA personnel will be delivering notification to those home near the treatments, if you do not receive one you are probably well outside the treatment areas.
The Idaho Department of Agriculture is the lead agency supporting Eurasian Milfoil control throughout the state. This effort has focused on Priest Lake over the past few years. A combination of treatment and diver survey and removal has kept this invasive species largely in check within this pristine water resource.
A key part of this program has been the use of US EPA approved herbicides that selectively target Eurasian Milfoil and protect native aquatic plant species. Aquatechnex has been selected over the years to support this work. The Department renewed our contract to continue supporting these efforts through the 2011-2012 period this past week. As survey work is completed and if populations of Eurasian Milfoil are deemed necessary for herbicide treatment, our team will be using this blog site to communicate our plans and actions on the lake.
Check back often for more information.
If interested, you can go to www.aquatechnex.wordpress.com to learn about new technologies we are using to map pollution inputs, compliance with TMDLs and invasive aquatic species.
Aquatechnex biologists will be targeting Eurasian Milfoil at two locations on Priest Lake tomorrow Tuesday October 5th.
ISDA divers have located some additional areas on Priest Lake that will be targeted with Aquatic Herbicides. A 1.7 acre infestation at Priest Lake Marina in Kalispell Bay and a smaller infestation at the beach adjacent to Beaver Creek USFS Launch on the north shore of the lake will be treated with Triclopyr.
There will be a restriction on the withdrawal of water for irrigation and potable use from the treatment areas until levels are below EPA standards for those purposes. Sampling will be performed to identify
ISDA divers have located some additional areas on Priest Lake that will be targeted with Aquatic Herbicides. A 1.7 acre infestation at Priest Lake Marina in Kalispell Bay and a smaller infestation at the beach adjacent to Beaver Creek USFS Launch on the north shore of the lake will be treated with Triclopyr next week.
ISDA staff and divers discovered these sites during the survey performed this summer. Contracted divers have been working on these sites over the summer, but the sizes are such that herbicides need to be applied now to injure the vegetative growth. Eurasian Milfoil auto fragments and spreads in the fall and winter months. One of the objectives of these treatments is to kill as much of this vegetation as is possible to help minimize this potential.
A decision on treatment dates for next week will be tentatively made and posted here on Friday of this week based on the weather forecast for next week. Please check back.
ISDA sampling and laboratory analysis conducted this past weekend and Monday have been completed. Residues of triclopyr herbicide have dropped below detection levels. Water withdrawals from this treatment area can now be used for domestic and irrigation purposes. If you have any questions, please use the log a case system on the tab at the top of the page and we will contact you.
ISDA officials collected and processed water samples for Triclopyr herbicide from the treatment areas and two sites outside the treatment areas yesterday morning about 12 hours post treatment. Their laboratory has provided results from that sampling.
The EPA label for the herbicides used indicates that water withdrawals from the treatment area should not be used for potable supply until herbicide levels are below 0.4 parts per million in the water. The label further indiates that water withdrawals for irrigation should not occur until herbicide levels are below detection.
Yesterday’s results are as follows: North Bear Creek Bay (Treatment area) 0.0855 ppm, South Bear Creek Bay (Treatment area) 1.330 ppm. Two samples were also collected outside of the treatment area, one to the west of the lake in untreated open water (0.0114 ppm) and one north of Bear Creek Bay along the homes there in an untreated area. The levels there were 0.0069 parts per billion.
As such, the potable water use restrctions outside the areas of the actual treatment area have expired. The levels within the treatment area still remain above the cut off for irrigation and the southern sample indicates above the potable water use restriction level.
If there are questions regarding this contact us through the log a case system above.
Aquatechnex biologists completed the application of triclopyr herbicide to Bear Creek Bay last evening (Wednesday July 28th). This application was timed to minimize the effect of wind driven currents on the treatment area prolonging contact time with the invasive aquatic weeds. Triclopyr is selective for this noxious weed and will not impact native aquatic plants sharing the same space.
The water use restrictions on this herbicide for potable and irrigation withdrawals will be in place within the treatment area until ISDA sampling indicates that levels have dropped below the EPA thresholds. This generally occurs within 2-5 days. Those results will be posted here as soon as they are delivered to us by ISDA staff.
If you have questions feel free to post a comment or use the log a case tab above and we will answer it at once.
