Beach Eurasian Milfoil Treatments June 3rd

Aquatechnex, working for Seattle Parks and Recreation, will be treating a number of City beaches with the aquatic herbicide ProcellaCOR for Eurasian Milfoil this coming Wednesday June 3rd.

This work is being performed under a permit from the Washington Department of Ecology.  ProcellaCOR is very effective against Eurasian Milfoil, an invasive aquatic species that can pose a threat to swimmers and impede rescue efforts if needed.

EPA has cleared this product for application to potable water reservoirs with no restrictions on delivery, there are no swimming restrictions, there is a 24 hour restriction on drawing water from the treatment area to irrigate.

A treatment map can be viewed at this link.  You can zoom and out, you can  also enter your address in the box above to see where you are located with respect to a treatment area.  Treatment areas are the red polygons, the water use restriction signs will be posted on shoreline properties within the blue polygons.

Click on this link to access treatment map

June 3rd Treatment Map

Seattle Beaches to be treated for Eurasian Milfoil this week

Aquatechnex biologists will be treated a number of the beaches in the Seattle Parks System this week for the invasive aquatic weed Eurasian Milfoil.  This plant can grow forming dense mats that area  threat to swimmers and habitat in these areas.  This work is being performed under a permit from the Washington Department of Ecology.

We will be applying Renovate OTF granular herbicide to these sites.  Signage will be posted with Water Use Restrictions at the parks and within a short distance each side of the Parks.  Ecology requires a short 24 hour swimming closure.

Signage will be posted on Tuesday May 21st and the application will take place Wednesday May 22nd.  The beaches will be closed for swimming for 24 hours post treatment.

A treatment map can be viewed at Treatment Map with Posting Buffer

Planning for 2019 Eurasian Milfoil Treatments underway

Aquatechnex biologists will be working with the Seattle Parks Department to manage the noxious aquatic weed Eurasian Milfoil at a number of park beaches and boat ramps this month.  This work is done to clear these areas for swimming for safety and to assist lifeguards in their work.

The areas will be treated the week of may 20th under a permit from the Washington Department of Ecology.  Check back for exact dates, tentatively this work will be performed on Wednesday May 22nd weather permitting.

A map of the treatment areas is viewable at Treatment Map

Aquatic weed treatments week of July 16th

Aquatechnex will be treating invasive and nuisance aquatic weed growth that is interfering with swimming and boating sites on Lake Washington the week of July 16th under a permit from the Washington Department of Ecology.  The schedule will be as follows:

Tuesday July 16th, Stan Sayers and Seward Park

Wednesday July 17th, Matthews Beach, Madrona Beach

Thursday July 18th, Madison Beach, Magnuson Beach, Leshi Marinas

Friday July 19th, Mt. Baker Beach, Prichard Beach, Lakewood Marina

Dense aquatic weed growth is both a threat to swimmers and an impairment to rescue workers during swimming emergencies.  The objective of these treatments is to limit the impact of this growth within high use areas and communities beaches to improve safety.

Questions can be addressed to the City Parks Department or Aquatechnex at 360-527-1271 or

2018 Treatment Program is announced

The first treatment for invasive Eurasian Milfoil at the Seattle Parks beaches and moorages on Lake Washington will be performed on Wednesday May 23rd.  Each location will be posted prior to treatment with water use restrictions.  There is a 24 hour swimming precaution required by the DOE permit and the beaches will be closed for this activity the day of treatment

A treatment map can be viewed at May 23rd Treatment Map

The water use restrictions apply within the yellow treatment polygon and within the blue buffer that extends 400 feet in each direction.

The treatments will start at Matthews Beach on the north end, and end at Prichard Beach in the south.  You may have to zoom in on the treatment map to search location.  You may also enter your address in the top right corner and determine if your home is within a treatment zone.

Eurasian Milfoil Treatments to Happen Wednesday, May 31st

Aquatechnex biologists will be treating the harmful introduced aquatic plant species Eurasian Milfoil at a number of Park Beaches on Wednesday, May 31st.  Eurasian Milfoil poses a threat to swimmers and can also impact rescue efforts if a swimmer is in trouble.

We will be using a US EPA and Washington Department of Ecology approved product that selectively targets this invasive aquatic species.  On Tuesday we will be posting signage at park locations where treatment will occur.  There is a 3 day restriction on drawing water from the treatment area of the lake to irrigate.  There is also a 24 hour swimming precaution and the City will be closing the beaches for this period.

The treatment map can be viewed at

You can zoom into a location and view it.  You can also enter an address and zoom to that location to see if this affects your property.  The yellow treatment polygon shows area to be treated.  The blue buffer polygon shows WA DOE Required Water Use Restriction Zone.  The restrictions that will be posted on lake shoreline areas within the blue buffer are a 24 hour swimming precaution and a 3 day irrigation restriction if you draw lake water to irrigation with.

Integrated Aquatic Weed Management Program for 2017

This summer, Seattle Parks and Recreation (SPR) will begin an integrated aquatic weed management program to control Eurasian Milfoil and fragrant water lily infestations at its lakefront properties on Lake Washington.

Controlling these weeds will improve water quality and recreational access at freshwater beaches, swim areas, moorages and other high-use recreation locations along the lake.

Mowing, hand cutting, and removal of the weeds will continue as in past years.  SPR will complement this work by using selected US EPA and Washington DOE approved aquatic herbicides.  This use is permitted by the Washington Department of Ecology (Ecology).  These herbicide have been screened and endorsed by Ecology as an effective solution to control these noxious and invasive weeds.

SPR has contracted with Aquatechnex, LLC to apply the selected herbicide.  This web page will be used to communicate with interested parties. A interactive ArcOnline web map will be added as soon as sites are finalized.  This page will also be updated just prior to treatment to inform the public as to where actions are occurring.