Water Quality Testing
Each year, GORA volunteers conduct transparency tests on the lakes using Secchi disks and the readings are submitted to the Government of Québec (Développement durable, Environnement et Lutte contre les changements climatiques). The aggregated longitudinal data are used to reveal general trends in water quality.
In addition to transparency tests, we also took samples in 2021 (for the third consecutive year) to determine the levels of phosphorus, chlorophyll, and dissolved organic carbon. As you may recall, these tests are done typically over a 2-3 year period in order to get a representative sample.
Results from all testing are now available at the following provincial website: https://www.environnement.gouv.qc.ca/eau/rsvl/relais/index.asp
For ease of reference, we have updated our own charts of results for each lake (see below). You will see that all four of the lakes scored very well. The province recommends that we do not need to continue to take the special sampling and that the lakes “be protected” to preserve this status, and for us, this reinforces the importance of boat washing and taking care of our lakes.
We are grateful to the Municipal Council for their 50% contribution towards the cost of these special tests over the past few years. We are also pleased to have received support from the MNA for Pontiac, André Fortin, with his $1000.00 contribution. We are very appreciative of their support for our efforts to protect our lakes.
A big thank you goes out to the “testing team”: Valerie Buchanan (Little Hughes), Nick Cushman (Hughes), John and Maggie Madden (McCuaig), and Stewart Wilson (Farm) for volunteering to collect the samples.
Transparency - How we do Secchi Disk testing
A Secchi Disk is a black and white circular disk, 8" in diameter. The disc is mounted on a pole or line, and lowered slowly down in the water. The depth at which the disk is no longer visible is taken as a measure of the transparency of the water. While Secchi Disk readings do not provide an exact measure of transparency, they are an inexpensive and straightforward method of measuring water clarity.
It is important to test for phosphorus levels because too much phosphorus leads to algae growth which can choke a lake by using up all the oxygen. Phosphorus enters a lake from the run-off from land surrounding a lake. This is why pesticides or fertilizers should not be used on lakefront properties. Phosphate-based products (detergents and soaps) and deficient septic systems can also be detrimental to a healthy lake.
Testing for chlorophyll helps to determine the level of algae present in a lake. While some algae is normal, elevated levels of algae can be very harmful to a lake.
Dissolved Organic Carbon
The tests for dissolved organic carbon are done to determine the extent to which the lake is coloured by organic deposits (wood, etc.). The more “coloured” a lake is, the more likely that it will impact the transparency measurements done with the Secchi disks.
Greater Otter Lake Residents' Association (GORA)
Association des Résidents du Grand Otter Lake (ARGO)