We may find ourselves in deep water!

Renaissance Lac-Brome

Another year gone by! Year in which the effects of climate change were evident. Think of the record rainfall in May, making May-June 2022 the wettest period in southern Quebec since 1940. These extreme precipitation events are having an increasingly marked and rapid negative effect on our lake as they bring, via runoff, large quantities of phosphorus to the lake, contributing to the proliferation of plants and algae. Brome Lake has reached its nutrient intake capacity: we may be in deep water!

Several factors are responsible for this: the ecological history of the lake, the number of dwellings, the large number of boats with powerful motors, the poorly vegetated banks, industrial, agricultural, and commercial activities, etc.

As this graph illustrates, the amount of phosphorus entering the lake tends to closely follow the amount of total precipitation.

No more inaction: we must react and quickly…

Climate change will only exacerbate the lake’s reactions if we do not adapt our activities and facilities. Meteorological projections for 2041-2070 for the Brome Lake region predict an increase of 10% in annual rainfall. This will have the effect of increasing runoff into watercourses and inflating the flow of tributaries which will transport more nutrients, contaminants, and sediments to the lake, causing eutrophication of the lake. This accelerated aging can, among other things, reduce the recreational and other uses of the lake. Remember that in 2006 and 2009 the lake had to be closed to swimming and other water activities due to the development of cyanobacteria. Currently, some sectors are no longer navigable due to the excessive presence of Eurasian watermilfoil and other invasive plants.

In this context, it is essential that we adjust our behaviour and that all water users and managers aim to reduce the rate of eutrophication of the lake to maintain all its uses. Citizens, municipalities, institutions, businesses, and industries are at the heart of the solution: it is a matter of a few gestures to make a difference. This is possible by applying various techniques such as: increasing the infiltration capacity of soils (driveways of permeable material); create landscaping that reduces runoff; set up a rain garden on your property; collect water from downspouts for watering; revegetate our riparian strips; protect wetlands; maintain ditches, etc.

A healthy lake is still attainable, and it is everyone’s responsibility! Happy New Year!