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Lake water quality measurement 


The lake water sampling protocol follows guidelines developed by the Lake Monitoring Network (RSVL). This approach is used to document water quality with regard to eutrophication.  The three variables analyzed within the framework of this program are: 

  • Total phosphorus (TP), this nutrient essential for the existence and growth of aquatic plants, is generally found in low concentrations in lakes.   However, this item has the highest need/availability ratio, around 80,000; this is why it is said to be a limiting factor in the growth of aquatic plants. This explains all the attention paid by lake protection associations to the control and reduction of phosphorus inputs. The phosphorus concentration of a young lake is 5 ug/l, for Brome Lake the readings we have are in the range of 12 ug/l to 18ug/l. 

  • Chlorophyll is a green pigment that is found in the composition of plants.   By measuring the concentration of chlorophyll, we have a good indicator of the biomass of the algae present in the water column. Again, the more dissolved phosphorus there is in the water column, the more algae there is, and the higher the chlorophyll level will be.   Eutrophic lakes often struggle with an overabundance of algae.   The chlorophyll level measured at Brome Lake is 10 ug/l, which places it at the lower limit of the eutrophic zone. 

Dissolved organic carbon arises from the decomposition of organisms. The measurement of dissolved organic carbon makes it possible to have an appreciation of the color of the water, which also affects its transparency. Therefore, the presence of living algae, such as those that are decomposing, influences the transparency of the water. 

Qualité de l'eau dans les affluents

The Ministry of the Environment

and the fight against climate change

take samples.  Updates are done on

the date of the last sampling.

The disc

by Secchi

We measure the transparency of water using the Secchi disc. This method invented 150 years ago represents an economical, simple, and reliable way to measure the transparency of water.

profondeur secchi.jpg
RLB à l'oeuvre Secchi_edited.jpg

Our outings

on the lake

We observe a growth of plants and algae when it is hot and   that after a busy weekend on the lake or after an episode of sustained winds, the transparency decreases.

Water quality monitoringin the tributaries

Since 2008, CLB has been monitoring the water quality of the six most important tributaries of Brome Lake, namely the Quilliams, McLaughlin, Argyll, Cold, Pearson and Inverness streams. 

Read more ...

IQBP à la sortie du lac Brome.png

Secchi results

et   temperature

2022 water

Here are the Secchi and water temperature results for 2022, compared to the previous 3 years in the first two graphs and compared only to 2021 for the last two graphs.

secchi 2019-2022
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