2024-07-09 - Water Quality Report

Lake Rosalind Residents,

It is that time of year when we begin to notice that yucky green scum on the surface of our water. This means that we are entering the blue green algae season. It is appearing a little earlier this year and we have been advised that this is due to the mild winter that we experienced with little to no ice on the lake. Many other lakes (including the great lake beaches) are experiencing the same conditions.

Please see the information below indicating the results of the most recent water testing. Thanks to Rick Kalte for sending this information to share with our residents.
The test results for microcystin toxin taken on July 8th arrived yesterday (July11) and are listed below in order of the flow of water through our lake system - Lake Rosalind Lake 2 (LR-2) through to Marl Lake 2 (ML-2)

LR-2 > 5.0 µg/L.....The lab was very busy with many lakes reporting early B-G algae blooms and they needed to do a dilution factor to get the actual number for LR-2. We think the actual number would not be more than 6.0µg/L . The lab will be giving actual numbers in the future and do dilutions if needed. Without a dilution the maximum they can report is 5.0 µg/L -----hence the (greater than)>5.0 µg/L for LR-2.

LR-1 4.33 µg/L

ML-1 0.869 µg/L

ML-2 0.680 µg/L

The Canadian Recreational Standard for microcystin toxin is 10.0 µg/L

We are waiting for the Algae ID results which will help to explain the large discrepancy in toxin levels between Lake Rosalind and Marl Lake.

The clarity for LR-2 was at 2.0 m and the clarity for ML-1 was at 5.5 m which shows there was more algae in LR-2 and hence more toxin.

The algae scums of last weekend and highly noticeable today become more evident due to calm nights, heavy rainfall and move with currents and light breezes to concentrate in specific areas around the lake.

Is it Safe to Swim?

Residents are the best judge of whether the water is safe to swim! Ask yourself these questions in order to guide your recreational decisions:

1. Has there been a heavy rainfall in the last 24 to 48 hours? (While small amounts of rainfall are unlikely to have much impact, you may wish to avoid swimming for 24 to 48 hours after heavy rains).

2. Have conditions been windy in the last 24 to 48 hours? (Wind can stir up the water making it cloudy. See question #3)

3. Is the water so cloudy that you cannot see your feet at adult waist depth?

4. Is there evidence of blue green algae/scums?

If you answered yes to any of these questions you need to consider the safety of the water quality for swimming.

Disclaimer - The Water Quality Committee has been working on a disclaimer to be used with every water test report offered to residents. This is important because we want to make sure that residents take their own precautions by consistently checking their waterfronts for scums in B-G algae season. This disclaimer will ensure that residents are not misguided with the testing reports that are provided.

Weather and other environmental factors affect the water quality in our lake. The test results that are provided through these communications reflect the conditions at the time of the assessment only. Water quality can change from day to day or even hour by hour depending on the weather and other conditions.

While the Water Quality Committee continues to review the wording for our own Disclaimer related to the communication and reporting of water testing results, please read the Draft below and feel free to offer comment by return email.

** It is important to note that these tests represent results from specific testing for microcystin and DO NOT provide broader results for other tests on bacteria, virus or parasitic pathogens. These tests are taken from designated locations on a specific date and time with the possibility of fluctuations in results in other areas of the lake such as shorelines and at other times and dates. For this reason, the test results are offered as a guide and information purposes only.

The Lake Rosalind/Marl Lake Water Quality Committee bears no responsibility for resident action (swimming, drinking) as a result of these testing reports.
Residents are reminded to keep pets and children out of the water when blue green algae scums are present or water clarity falls below 1m. All residents are advised to never use lake water as a drinking source.