EURASIAN WATERFOIL
Eurasian watermilfoil is becoming an increasingly significant threat to Lake Davignon. Action is required to stop its spread.
Pictures : ©City of Cowansville
BENTHIC BARRIER (TARPING)
2025 Tarping Operation
The 2025 operation currently underway is being carried out by the RAPPEL team.
The first step involves removing the weight bags from the 2024 operation. RAPPEL divers are retrieving the bags from the lake bottom. Following this, the divers will proceed with manual harvesting to remove Eurasian watermilfoil growing near the barriers.
2024 Tarping Operation
The 2024 tarping operation was once again supervised by RAPPEL. It was carried out in two phases: the first in July to remove the ballast bags from the 2023 operation, and the second in August to install new burlap tarps in different locations. More than 40 volunteers joined us during this operation, installing 64 large tarps and 7 small tarps to cover an area of 21,726 m2.
2023 Tarping Operation
The 2023 tarping operation, supervised by RAPPEL, took place from July 31 to August 16. Thanks to the exceptional work of over 70 volunteers, the operation was completed a few days earlier than scheduled. A total of 34,000 m2 was covered with burlap matting.
The CSBVLD collaborated with the City of Cowansville, which commissioned RAPPEL to carry out this major project aimed at protecting our body of water.
This effort would not have been possible without the support of more than 70 volunteers. We extend our heartfelt thanks to them for their dedication!
Mise à l'eau d'une toile de jute pour l'opération de bâchage
Mise à l'eau d'une toile de jute pour l'opération de bâchage
Formation par le RAPPEL en présence de Radio-Canada
Mise à l'eau d'une toile de jute pour l'opération de bâchage
Photo: 31 juillet 2023
Remplissage des sacs de lestage
Plus de 7000 sacs de lestage remplies
Une belle équipe de bénévoles
Remplissage des sacs de lestage
Ballast bag filling event.
In order to hold down the tarps over the Eurasian watermilfoil beds, we needed more than 7,000 bags of gravel weighing about 10 lbs each. The filling event took place at the Désourdy boat launch from July 18 to 21, 2023.
Our volunteers were amazing!
Eurasian watermilfoil has gradually appeared in Lake Davignon. As early as 1993, a study reported observations of Eurasian watermilfoil in the lake. Nearly thirty years later, we realize it is high time to address the problem. The CSBVLD has committed to fighting the spread of Eurasian watermilfoil and limiting its proliferation.
Description.
Eurasian watermilfoil (Myriophyllum spicatum) is an invasive exotic aquatic plant found in several lakes across Quebec. Over the years, it has become a significant threat to the health of waterways and lakes.
The stems of Eurasian watermilfoil are rooted in the substrate (sediment) and can reach lengths of up to 6 meters. Near the water's surface, they branch out and can continue to grow horizontally, producing emergent flower spikes. The plant then forms a dense canopy on the water's surface.
Its leaves are finely divided like a feather and arranged on the stem in whorls, typically in groups of four. Each leaf is composed of 12 to 24 pairs of leaflets (also called 'segments'). The average distance between the whorls is more than 1 centimeter.
Copyright©CRELaurentides
Attention! It is possible to confuse the eurasian watermilfoil with many other species including the following six indeginioous watermilfoils.
Why fight this plant?
Once well-established in an environment, Eurasian watermilfoil is difficult, if not impossible, to eradicate. The dense mats resulting from severe infestations can create various negative ecological and economic impacts on bodies of water:
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Acceleration of organic matter sedimentation and thus the eutrophication of the lake.
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Alteration of and competition with native plants present in the lake (disrupting the balance of the natural ecosystem).
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Serious hindrance to recreational uses such as swimming and boating.
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Decrease in property values for shoreline homes.
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Decomposition of plant mats, which can lower dissolved oxygen levels in the water and negatively affect fish populations.
Watch the video from RAPPEL about the eurasian watermilfoil
Myriophylle : L'envahisseur marin
(In French) The eurasian watermilfoil is an invasive exotic species that strangles the lakes and rivers in which it is spreading. It is spreading at a rapid pace. Battling this aquatic invader is not a simple task.
View the episode
La semaine verte
Infested zones in Lake Davignon.
The OBV Yamaska report on the presence of Eurasian watermilfoil in Lake Davignon, submitted to the City of Cowansville in December 2020, confirms infestation zones that are considered high priority. Joint actions (City of Cowansville and CSBVLD) are planned to address the issue in the short term.
Planning must also begin immediately for medium- and long-term projects. Considerable effort and investment will be required to control the infestation. To achieve this, we must rely on the collaboration of all our partners (City of Cowansville, OBV Yamaska, MRC Brome-Missisquoi , municipalities within the watershed, residents, and users) and seek funding from various levels of government to support our projects.
Installation of Buoys: Navigation through Eurasian watermilfoil beds is strictly prohibited. Buoys installed around infestation zones will serve to inform users. Employees of the Centre de la Nature will be trained to advise rental facility users to avoid navigating through infested areas.
It is essential to understand that Eurasian watermilfoil has the ability to reproduce through fragmentation. This means that a small severed piece of the stem can take root and give rise to a new plant.
Lake Davignon now has its boat washing station
Before hitting the water, wash your boats
The boat washing station at the Centre de la nature de Cowansville allows you to clean watercraft that have navigated other bodies of water, helping to limit the spread of invasive aquatic species.
The wash station is available for self-service at all times during the Centre de la nature's operating hours.
Learn more: Town of Cowansville
Decontaminating boats, trailers, and equipment used in aquatic environments is a recognized practice for curbing the introduction and spread of invasive aquatic species from one body of water to another. Let’s apply these four quick, simple, and effective steps right now:
1.
INSPECT AND REMOVE
Inspect the boat, trailer, and equipment and remove all clumps of plants, visible organisms, and mud. It is important to dispose of these residues in a safe location, ensuring they are not carried away by the wind and do not reach another body of water, such as a stream, pond, storm drain, etc.
2.
EMPTY
Drain all the water that may be on board and in the various parts of the boat, including the bilge, the bottom of the craft, livewells, the motor, bait wells, etc. The same applies to all other containers, compartments, and equipment that have collected water or could contain it, such as coolers, soaked clothing, etc.
3.
CLEAN AND DRY
Once the inspection is complete, you must proceed with cleaning the boat, trailer, and equipment used in the aquatic environment. It is recommended to use a pressure washer (2600 psi). Cold water is sufficient, but using hot water at a temperature of 60°C (140°F) kills organisms dislodged by the pressurized water jet. If you do not plan to visit another body of water immediately, or if you are storing your equipment for the rest of the season, drying the boat, trailer, and equipment may be sufficient (5 days at a humidity level of 65% or less). Sub-zero temperatures during winter storage also allow for decontamination. However, if you plan to visit another body of water in the near future, cleaning is strongly recommended
4.
REPEAT
Repeat these four steps every time you plan to visit a different body of water.
To know more
Eurasian Watermilfoil: An Underwater Battle
After 9 years of fighting Eurasian watermilfoil, the strategies and sustained efforts to slow its spread are starting to produce encouraging results in Quebec's lakes and rivers.
