1. Budget:

The board has approved $2,000 for this project.

Materials needed and cost to date are:

– $321.93: geotextile canvas size 40’x50 (this gives 5 mats size 10’x40′ long)

– $50: for 9 steel rebar for a 10’x40′ mat

– For one mat: tape ($7), rope ($10), grommets ($8), sewing the mat ($60?), all donated by some fund directors.

Here’s the breakdown it cost us for a 10’x40′ lake mat

– geotextile fabric for one mat: $64

– 9 steel rebar: $50

Total: the cost to us for one mat was $104 versus $550 if we bought one already made with rebar for a 10×40

The total spent so far on this project is $321.93 + 50 = $371.93

2. Manufacturing method:

The geotextile fabric we chose is made from propylene and purchased from Dubois Agriculture. This is the same material used in agriculture and is environmentally friendly. It comes in a large 40’x50′ roll and is black on one side and white on the other.

We decided to start with a single mat and cut a 10’x40′ material from the roll, as this seems to match the standard size used in projects like ours and seems manageable enough. Steel rods are also available in 10′ lengths and 3/8″ thicknesses from materials centers,

So we made the mat ourselves and followed the recommended steps for a 10′ x 40′ long lake mat. This involved sewing 9 loops spaced 5 feet apart into the mat to enclose and hold the steel rebar. For this step, we used our usual domestic sewing machine.

Steel reinforcing bars were then placed in the loops 5 feet apart to anchor the mat and also prevent it from swelling too much between each bar.

As the geotextile material we chose was completely impermeable, we had to place a few 2-inch-wide slits spaced a few feet apart to allow the gases from the bacteria in the water to infiltrate; otherwise swelling of the mat would be inevitable. All slots were reinforced with tape to prevent the material from tearing. The loops housing the steel reinforcing bars were also sealed with tape to prevent the reinforcing bars from falling out during installation or removal.

Finally, we also attached a 1 cm diameter rope to each distal end of the mat to create handles. This allowed us to stretch the mat at both ends during installation. We also attached a buoy to one end of the handle so that it could be retrieved. Please check the attached photo of the lake mat as it is washed after removal from the lake.

3. Location and method of installation:

We looked at 3 different places to install the mat. We finally decided to place it in the Bassin du Pavillon Monfort as this is the least frequented by motorized boats, and at the time we noticed a pondweed starting to grow in large dense clumps. We thought that this pondweed looked more like what we’d be facing if we tackled Eurasian water milfoil. What’s more, it was in an area that could be monitored regularly.

The best time to place these lake mats is in early spring, as soon as the snow melts and the water is navigable. It is recommended to leave the mat in place for at least 6 weeks up to 9 weeks to avoid aquatic plant growth. The mat was installed about 100 feet from the shore, about a third of the way to the Pavilion after crossing the Monfort Bridge. Installation was carried out using non-motorized boats, but this proved very, very difficult. It is preferable to use a motorized boat such as a pontoon to help control the installation against the current. In addition, it’s best to install the mats in calm weather.

We installed our mats on June 26, 2022 and removed it 6 weeks later on August 6, 2022. When it was installed, there were very small plant shoots starting up. At the time of removal, there was a huge dense cluster of plants all around the mat, but none growing under the mat. We were very pleased not only with the result, but also with the fact that we were able to manufacture and install this mat in relatively deeper water. We now have the tools and knowledge to pass this information on to the community should we need to control an invasive aquatic plant in the future, quickly and cost-effectively.

Conclusion and update for 2023:

This pilot project has been a success, proving not only that we can work together as a community, but also that we can take care of our lake if need be.

It’s worth mentioning here that since the start of this project, there has been growing concern about the spread of a native pondweed called Potamot à larges feuilles alias Potamegaton Amplifilious, particularly in the Pavillon Monfort pond. This concern was first expressed in 2021, but was not taken seriously until late summer 2022. Many now recognize that it is a plant that was present in our lake in the past, but is now spreading and growing at an alarmingly faster rate. This concern has prompted some Monfort-area residents to apply to the Fund for another project, which seeks the advice of a biologist (Louise St-Cyr) who has worked in lake analysis and management for many years. In her report, she expresses her concern about the spread of this plant to the rest of our lake, mainly because there is a lot of circulation from the Pavillon to the rest of the lake, and also because our lake is relatively shallow all around and has a lot of sediment. His report will be sent to all Fund members.

A group of Monfort-area residents independent of the Fund also got together and, with the help of some of the Fund’s trustees, developed an efficient method of making multiple geotextile lake mats. They bought themselves a sewing machine for the bags and also purchased their own mats. It’s important to mention that their project was not financed at all by the Environmental Fund. This group paid for everything themselves.

Since this spring, some 25 mats have been built by Montfort residents in 2-3 days. Their intention is to clear their dock so as not to spread broad-leaf pondweed to the rest of the lake. The Ministry of the Environment allows lakeside residents to keep their docks and swimming areas free of aquatic plants, either by manually removing aquatic weeds or by using lake mats.

Since this spring, some 25 mats have been built by Montfort residents in 2-3 days. Their intention is to clear their dock so as not to spread broad-leaf pondweed to the rest of the lake. The Ministry of the Environment allows lakeside residents to keep their docks and swimming areas free of aquatic plants, either by manually removing aquatic weeds or by using lake mats.

The sad news here is that this pondweed is so aggressive this year and so endemic to the Montfort Basin. It has literally engulfed the entire Montfort Basin. It’s spreading rapidly along the shoreline and docks in the Monfort area. As a community, we need to be aware of this new spread, as our municipality is also committed to finding a solution to control the spread of this plant.