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.

We also collected samples in 2019 to allow provincial testing for levels of phosphorus, chlorophyll, and dissolved organic carbon. These tests are done periodically and typically for 2-3 consecutive years in order to get a representative sample. They were last done during the years 2010-2012. The provincial government reinstated the testing in 2019.

Thank you to Stewart Wilson (Farm Lake), Nick Cushman (Hughes Lake) and Kim and Gord Robertson (McCuaig Lake and Little Hughes Lake) for devoting their time in 2019 to conducting these tests and collecting the samples. 

All four of our lakes scored very well. The province recommends these lakes “be protected” to preserve this status, and for us, “protection” includes a continued push for strict boat washing measures. 

Transparency - How we do Secchi Disk testing

A Secchi Disk is a black and white circular disk, 8" in diameterThe 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. 

Phosphorus

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.

 

Chlorophyll

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. 

A note regarding interpretation of 2019 results for phosphorus, chlorophyll, and dissolved organic carbon compared to those from 2010-2012 – they only represent one year. The cost for the analysis of the samples taken in 2019 was $476 per lake (total cost $1904). We thank the Municipality of Otter Lake for sharing the cost 50/50 with GORA.

May 2020 Status

In March 2020, we were informed by the Government of Quebec that lake water testing would not resume as usual in April 2020 due to the fact that government resources are being dedicated towards addressing the COVID-19 situation. We will begin testing when the Government gives us the “green light”.