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.
Despite the pandemic, we continued to do the lake water testing in 2020 (in a safe manner). Results from that 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 the lakes “be protected” to preserve this status, and for us, this reinforces the importance of boat washing and taking care of our lakes.
Results include those done for measuring water clarity (using the Secchi disk) and the separate sampling done for the second 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.
We are grateful to the Municipal Council for their 50% contribution towards the cost of these special 2020 tests. We are also pleased to announce that the MNA for Pontiac, André Fortin, has recently provided $1000.00 to GORA which covers the remaining 50%. We are very appreciative of his support for our efforts to protect our lakes.
The Ministry of Environment is recommending that we continue to take samples for phosphorus, etc. in 2021 and perhaps a couple more years or until they can make adjustments to data from samples taken in previous years. This is due to a new method of analysis that they are using. The good news is that the province will cover 75 percent of the costs, so, the cost for GORA would be reduced to $125 per lake per year.
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)