The Health of the Lake
Since 2001, there has been a systematic monitoring of fecal coliform levels for all five beaches. Since 2007, samples for the analysis of phosphorus levels were also taken on a regular basis. As part of its participation in the Lake monitoring volunteers network, the association also conducts tests on water transparency. This is easy to measure and is useful in showing long-term changes in water quality and lake condition.
As you will notice in the results below, despite its clearness and acceptable water quality, the health of the lake remains fragile.
Lac Doré has faced a few problems related to cyanobacterial blooms in recent years. In order to be aware of what actions to take and priorities to ensure the preservation of the health of Lac Doré, Abrinord has produced a summary on the state of its watershed.
The summary (April 2016) includes the important and available information on Lac Doré. It will be used, among other uses, as a guide in decision-making with respect to actions to take to slow down eutrophication (premature aging) of the lake.
Click here to view the Summary-report of Lac Doré (in french only).
Water Tests Results
WATER QUALITY TEST (PHOSPHORUS AND FECAL COLIFORMS)
2018 report on the health of the lake : 2018 report
In summer 2011, a first occurrence of cyanobacterial blooms (also called blue-green algae) was observed in the lake. These events were repeated in 2012, 2013 and 2015* (*cases not reported to the Ministry ). In 2011, when the the first bloom had appeared (was identified), phosphorus levels reached a concentration of 9 mg/m3 (June 2011). In September 2013, phosphorus concentration increased to 13 mg/m3. These concentrations are at the limit for an acceptable level for the lake. Phosphorus presence is not as a result of rain water, but comes from fertilizers used on lawns and flowerbeds of lakeside and non- lakeside residences." - Excerpt from the 2015 report on the health of Lac Doré from Roger Tessier, environmental consultant.
"Based on results, Lac Doré shows little or no signs of eutrophication. This lake must be protected. To maintain its state and uses, the MDDELCC recommends the adoption of preventive measures that implicate limiting feed compounds. " - 2015 RSVL Report
RESULTS OF PHYSICAL AND CHEMICAL TESTS - Carried out as part of the RSVL
Phosphorus test results prior to 2015 are shown in the following table
FECAL COLIFORMS AND PHOSPHORUS (prior to 2015)
Fecal Coliforms/100 ml
WATER TRANSPARENCY TEST
An estimate of the average water clearness was obtained through 8 measurements of the Secchi disk depth in the summer of 2015. This transparency of 7.2 meters equates to very clear water. However, in 2009, the average was 7.4 meters, a loss of 0.4 meters in transparency. The measurements in coming years will provide more info on this variable.
Source : Rapport RSVL 2014
RSVL RESULTS 2015
Comment agir pour protéger la qualité du lac.