Eurasian Watermilfoil - Dealing with the Threat

FLCA Receives grant from the ontario trillium foundation


The FLCA is very excited to announce that the Ontario Trillium Foundation, an agency of the government of Ontario, approved our application for a grant to help us with our efforts to control the spread of Eurasian Watermilfoil (EWM) in Farlain Lake over the next three years!  Over the past five years, we have worked hard to develop strategies to  control the infestation of this very aggressive aquatic plant based on extensive research, consultation, networking and experience. The grant will help provide us with the resources we need to purchase equipment, supplies and services needed to manage the EWM and protect the future of our lake.  It’s hoped that our learning and experience will also help other communities dealing with the EWM.


What is the Eurasian Water Milfoil (EWM)?

EWM is an extremely aggressive non-native invasive water plant that forms thick underwater stands of tangled stems and vast mats of vegetation on the water’s surface, especially in shallow lakes like Farlain Lake.  It was discovered in Farlain Lake in 2012 during a FLCA aquatic plant study of the lake.  It had not been observed by Ontario government organizations studying water quality or the fisheries of the lake prior to that. The pioneer colony (original infestation) was limited to a small isolated area less than one acre in size on the southwest shoreline of the lake.

EWM is considered one of the most widely distributed aquatic invasive species with records of EWM confirmed in 47 continental USA states as well as the provinces of British Columbia, Ontario, and Quebec. Various organizations have been combatting EWM for years. For example, Lake George in New York State’s Adirondack Park has been managing EWM for 32 years. The Okanagan Basin Water Board in British Columbia has been combatting EWM for the past 40 years. Control budgets vary depending on the severity of the problem and the size of the water body. For example, the Christina Lake, British Columbia, EWM control program is $213,000 annually. To manage EWM and improve the lake’s water quality in Puslinch Lake Ontario, through dredging the annual operating cost is approximately $150,000.

EWM will grow from plant fragments created from physical breakage by boaters, anglers, and other disturbances (e.g. forceful wave action, aquatic animals, fish, waterfowl, etc.) during the summer months. In late fall during the end of its growth period EWM becomes brittle and naturally break apart. Plant fragments are the primary means of EWM reproduction; they float on the surface and are dispersed by wind and wave actions to other areas where they sink and colonize into new plants. In optimum water temperatures (15°C - 35°C) EWM plants can grow 30 cm per week.

Why is EWM a Problem?

EWM is an extremely aggressive invasive aquatic plant that forms thick underwater stands of tangled stems and dense floating mats of vegetation.Some of the problems associated with EWM include:

•Recreational activities such as boating, fishing, and swimming are impeded by dense growth at or near the surface.

•Shoreline property values can be de-valued. EWM choked bodies of water can depress real estate values up to 20%.

•The lake’s ecosystem will be altered. EWM will displace important native plants thus harming fish and wildlife habitat. Dense floating vegetation becomes breeding habitat for mosquitoes.

•Stagnant oxygen-depleted conditions are often found in association with dense beds of EWM. Sudden nutrient release caused by late-season die-back of extensive plant beds may cause nuisance algae blooms.

•Costs to manage EWM growth are borne by either local citizens, lake management

organizations, and/or local governments.

What Are We Doing to Address This Threat?

The FLCA implemented a EWM Control Program in 2014 under the leadership of the EWM Steering Committee working with the FLCA Board, and with the support of many volunteers from the community.  We also appreciate the ongoing support we receive from the Severn Sound Environmental Association (SSEA) and the Township of Tiny.  There are no recent research studies in EWM in either the USA or Canada on effective control methods.  The FLCA needs to rely on proven safe control methods to manage the growth of the plant on the lake.  Initially focusing on hand harvesting using professional divers, additional methods have been added on a trial basis.  Based on our learning and additional research each year, additional strategies have been added.  Hand harvesting was augmented in 2017 using a DASH (diver assisted suction harvesting) system to expedite the removal of the plant from the water for collection and dispersal. Reward, a government approved herbicide, was applied to a limited targeted area in the pioneer colony and one other area by licensed applicators in 2018.  Benthic or "bottom mats" were applied to a limited area of cut EWM on a trial basis.

For details on the 2018 control effort, please download the PDF Managing the Eurasian Watermilfoil on Farlain Lake here.

These control efforts come at a cost both financially and in volunteer resources.  The FLCA is fortunate to have a very dedicated group of volunteers on the Committee, helping with fund-raising, the physical labour during harvesting and ongoing research.  A major fund-raising campaign was launched in 2017 and continues.  We have sincerely appreciated financial support from Tiny Township and community sponsors as well. In May of 2018 an application was made to the Ontario Trillium Foundation (OTF) for a grant to fund control efforts for the next three years and we are thrilled that the grant was approved! 

What's Next?

An Integrated Management Plan to guide the FLCA in its control efforts over the next three years has been developed and shared with the Ministry of Natural Resources and Forestries (MNRF), Department of Fisheries and Oceans (DFO), the SSEA and the Township of Tiny.  An Education and Training Manual has also been developed.  Plans are well under way for the 2019 EWM management project which will include mapping and monitoring of the infestation, education and training, application of the herbicide to  targeted areas, harvesting of the EWM in the infested areas, and evaluation of the results. 


We are dealing with a critical issue affecting the long term health of Farlain Lake’s ecosystem, lake usage, and property values.

There are five key challenges to managing EWM in Farlain Lake...

1. Sustained Funding

Up until now, the burden of raising funds to support our control efforts have fallen to the community.  Between 2017 and 2018, over $46k was raised through donations, special activities, silent auction, sponsorship and support from the Township of Tiny.   The OTF grant will provide the financial resources needed over the next three years.  However, this threat is not going to go away and funding will be required for the long term.  The balance of community funds available following the work done in 2018 will be used to start a  "war chest" to allow us to continue managing the EWM beyond the three years of the grant.

2. Volunteer Sustainability

Only a small core group of volunteers undertake the majority of the EWM control program work throughout the year. This group of dedicated volunteers represents 1% of the lake community’s population.  Those who volunteer also have personal and family commitments, limited free time whether they are fully employed, partially employed, or retired. There are community residents who have health and mobility issues but are able to volunteer where they can. The reality of the volunteer situation is that volunteer fatigue will become a reality as the same volunteers are called upon time and time again to undertake the necessary fundraising and EWM control work. Ongoing effort to engage the rest of the community and beyond is needed in order to avoid volunteer burnout.

3. EWM Control Options

Our options of proven control methods are limited. There are no viable biological control methods. Unlike the United States where the primary control method is the application of various types of aquatic herbicides, the only herbicide approved by Health Canada to manage invasive aquatic plants is a contact herbicide (brand name Reward) that only slows the plant's growth rather than kill the plant. Mechanical harvesting and chemical herbicides only provide short-term control and have negative impacts on native vegetation.  As we continue to try alternative strategies, research and evaluation are necessary to determine the most effective approach for Farlain Lake and to be able to share the results with other affected communities.

4. Natural Circumstances

Control efforts will be affected by uncontrolled and unpredictable natural circumstances (e.g. weather patterns, water level fluctuations, variations in water temperature, etc.).

5. Education/Awareness

It is vitally important for lake community members, their guests and visitors to the lake be aware of the threat EWM poses to the lake’s values we all share. The FLCA has erected an information kiosk with the support of the Township at the boat launch area on Andrew Drive, it has created publications and displays, and the Association has distributed information door-to-door around the lake community as well as mailing information directly to property owners’ home addresses. The FLCA has written articles for FOTTSA's Tiny Cottager newsletter which is distributed to each property owner online and via mail. FLCA members receive ongoing EWM related information through the FLCA website, newsletters, and E-blasts. Each FLCA Annual General Meeting features an update on the EWM issue. Yet too many of our lake community residents are oblivious to the EWM threat and the fact that their recreational activities (e.g. boating, angling, etc.) contribute to the spread of EWM within the lake. 

For further information or questions about our EWM management effort, please email us at This email address is being protected from spambots. You need JavaScript enabled to view it. .