There will be two major efforts on Lake Stevens this summer.
The first will be a treatment with Aluminum Sulfate. This is tentitively scheduled to begin the week of June 3rd. Alum is a technology that captures phosphorus and removes this key nutrient from the water column. This reduces the carrying capacity of the lake to produce problem algae blooms. This operation is pending approval by the City Council that is expected to work on this at their next meeting. When approved, the crews will be working to apply this material throughout the deeper portions of the lake in this time frame.
The second operation will be the continued implementation of the City’s Eurasian Milfoil Management Program. The 2011 application of Renovate Aquatic Herbicide did an excellent job of suppressing this noxious aquatic weed. Our team will be surveying the lake in June and have scheduled a treatment to some areas of the lake that showed potential for regrowth during the 2012 summer surveys. We will post more information and a map on this site as those surveys are completed.
Wind Blown Blue Green Algae Accumulating on South Shoreline
Our team observed the Blue Green Algae accumulation on the south end of the lake during our aerial imaging mission yesterday. The City and County have collected samples and sent them to the laboratory. They will announce results when they have them. Our team has been working on technology to help solve these problems by targeting phosphorus and KING 5 TV did the following story on those efforts this past Monday.http://www.king5.com/news/environment/New-weapon-used-in-blue-algae-battle-in-Federal-Way-158508465.html
Aquatechnex biologists have started phase two of the Lake Stevens Aquatic Plant Management Program. In 2011, our team mapped and treated approximately 134 acres of the invasive aquatic weed Eurasian Milfoil. A review of the treated areas at the end of 2011 showed that control had been achieved in those highly infested locations.
Eurasian Milfoil is an aggressive aquatic weed, the effort this year will be focused on locating, mapping and treating remaining plants in the system. There are three steps that will be followed in this effort.
The first was a review of general conditions present in the lake, our team traveled to last years treatment zones and reviewed conditions this past Wednesday. We also traveled to four locations where residents has requested we check for Eurasian Milfoil. While there are native aquatic plants such as White Stem Pondweed and Elodea present in some of these areas, no milfoil was observed.
The second phase was to collect aerial imagery to help pinpoint aquatic plant beds for ground survey. This was completed yesterday. We have reviewed this photography as part of the process to get organized for the ground survey and this has helped us locate areas of interest. We also observed the blue green algae bloom on the south end of the lake that has caused some residents concern.
The third phase will be a detailed survey this coming week. All areas of the littoral zone will be reviewed and any milfoil found will be mapped and recommendations for management presented to the City for consideration.
We will be repeating this process later in the summer as well.
Last night the City of Lake Stevens Council approved a measure asking Aquatechnex to move forward with the implementation of the Lake Stevens Integrated Aquatic Vegetation Management Plan. This plan was developed by the City and Snohomish County water quality experts in 2010. Last year in 2011, Aquatechnex was selected to implement the first major component of this plan, our team mapped approximately 135 acres infested with this noxious weed and treated it with a selective herbicide, Renovate OTF. The results of that treatment were found to be excellent.
The program for 2012 will begin with two surveys of the lake. One will be performed in the spring to note any surviving milfoil plants and review areas of the lake that were not treated in 2011 because of little or no milfoil present. The second survey will be held later in the summer. Based on results of the survey, Aquatechnex may propose additional actions to the City for consideration.
Anyone living on the lake that has a concern about milfoil in their area, we’d like to hear from you prior to each survey effort. You can email email@example.com or you can click on the “Log a Case” link above to contact us. We will be using this site over the 2012 season to convey our findings and keep the community informed.
As noted below, the EPA has set a drinking water tolerance for the herbicide Renovate OTF. Water can be used for potable supply after levels have dropped below 0,4 parts per million or ppm.
Lake Stevens was sampled at representative locations within treatment plots last Thursday, 48 hours post treatment. These samples were shipped to the laborabory and the analysis arrived this morning.
All treatment plots sampled showed levels below the drinking water tolerance and the potable water use restriction for the lake is now lifted. The irrigation restriction remains in place, additional sampling will be conducted this week and results posted here as well.
Aquatechnex biologists worked through the day to complete the Lake Stevens Eurasian Milfoil treatment. The lake was posted on Monday afternoon notifying residents of EPA and DOE water use restrictions. Our application of Renovate OTF aquatic herbicide began about 6 am this morning and was completed about 7 pm. All areas on the treatment map, see page tab above, were targeted.
Our team will begin sampling the lake on Thursday so we can notify residents when potable water use and irrigation restrictions have expired. Please check back often as we will notify you of results here when they are received from the lab.
Aquatechnex biologists are gearing up to begin the treatment of Eurasian Milfoil in Lake Stevens on Tuesday July 12th. Monday will be spent on logistics, posting the required signage on the lake and on the shorelines, moving the herbicide into position and getting treatment vessels calibrated and organized. Tuesday morning very early treatments will begin barring a weather event that precludes us getting going effectively. A couple of points to keep in mind.
The signs that will be posted on your property on Monday are required by the Department of Ecology. The wording is as they specify on these signs.
Swimming: The United State Environmental Protection Agency has approved Renovate, the herbicide that will be applied, with no restrictions on water use for swimming and water sports. The Department of Ecology advises that people not swim in the treatment area for 12 hours post treatment and that langauge is required to be on the signs posted.
Drinking: The EPA requires that anyone drawing water from the lake for potable consumption wait until sampling indicates that herbicide levels are below 0.4 parts per million. This generally happens within 2-5 days and we will be sampling and posting that information here.
Irrigation: Renovate is a herbicide and will impact some plants. The EPA requires that those drawing water from those areas of the lake that were treated wait until herbicide levels are below 1.0 parts per billion, this generally occurs within 2-5 days and we will be sampling.
Interaction with our application team: Often lake residents have questions and attempt to hail our treatment vessels during application. Our vessels are using GPS guidance and tracking to make sure our applications are even and provide the coverage we necessary to target all the growth present. Stopping that process and coming to shore impacts the efficiency of the treatment. If you have questions, go to the log a case tab on this page and enter that information. That gets transferred to us in the field and we can respond during breaks or while reloading the boats. Thank you for your understanding.