On the main road north of the bridge at Montfort, winter maintenance of the long shoreline requires large quantities of sand and de-icing agent to ensure safe traffic flow. This sediment eventually sinks, mainly in spring, and ends up in the lake. Residents who have lived in Montfort since their youth remember when it was possible to dive from the bridge. The water was at least 6 feet deep. Last summer, in 2023, the depth was around 16 inches. The accumulation of sediment is constant from year to year.

To remedy the situation, the Ministry of Transport (MTQ) installed a sand trap in 2013. Two collectors, one on each side of the road, channel some of the sand and sediment into the trap along with water from snowmelt and rain. The purpose of the trap is to retain the sand and sediment and allow the water to flow into the lake via a large pipe. Unfortunately, the trap isn’t enough to hold back everything. When it rains heavily or when there’s a thunderstorm, we sometimes see large banks of sand and sediment being dumped into the lake through the pipe. The sand trap should be emptied more often.

In 2014, Madame Robitaille, then director of the municipality’s environment department, had obtained government authorizations to carry out dredging. At the time, there was about 2 feet of water under the bridge. The dredging was carried out in August 2015. The dredging had brought the depth down to around 4 feet. Today, with a depth of around 16 inches, it appears essential that another dredging be carried out. In the fall of 2023, the Environmental Fund made a request to the municipality and we are awaiting the response regarding government authorizations.

Biologist Louise St-Cyr reports that pondweed reproduces by vegetative fragmentation, as does native milfoil, which is also present in the lake. The considerably reduced current under the bridge, a choke point due to the accumulation of sediments, encourages the increasingly rapid growth of these aquatic plants. We would therefore like to see another dredging operation carried out as soon as possible, in the summer of 2024.