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Water Quality Update for September 17, 2019

After a “quiet” week with minimal harmful algal bloom reports from volunteers and the public, activity picked back up again today, with several reports and samples collected from the west side of the lake. Photos coming in showed areas of surface streaking and shoreline accumulations of algae from several spots around the lake. We are starting to get more algae bloom reports from the southern half of the lake.

And while the sunny, calm, warm weather forecasted for the next several days will be great for getting in those end-of-summer activities, it is also ideal conditions for blue green algae (cyanobacteria) to pop up. As we cannot predict when or where blooms may appear, please continue to use your visual indicators before recreating in the lake.

September has been the month when we have experienced our most significant bloom events, and last year was no exception, with many blooms being designated as “Confirmed with High Toxins”. This year, the DEC will not be releasing toxin (microcystin) values associated with the samples collected until the end of the season, but is updating their NYHABS webpage when a bloom is confirmed with high toxins.

What does this mean for our drinking water?

The six Canandaigua Lake water purveyors (the City of Canandaigua, the Village of Newark, the Village of Palmyra, the Village of Rushville, the Town of Gorham, and Bristol Harbour) are working alongside the Geneva District Office of the Health Department and the New York State Department of Health to monitor the public drinking water for the presence of toxins associated with harmful algal blooms. Samples of the public drinking water are collected twice a week and sent to a State approved laboratory to determine if toxins are present. To date, all finished water samples have been non-detectable for the microcystin toxin. If there is a detectable value in the finished drinking water (above 0.3 micrograms per liter), the DOH, in cooperation with the affected public water system, will notify the public when alternative water should be used for drinking, making infant formula, making ice, brushing teeth and preparing food. CLWA and the Canandaigua Lake Watershed Council will strive to assist in getting the word out from the DOH in the event that this situation arises.

Users of private water systems (those not on municipal water, who are using a surface water intake or nearshore well) face further challenges when there are high levels of blue green algae and cyanotoxins present in the lake due to the varying capabilities of household treatment units to remove cyanotoxins. Private system users are encouraged to actively monitor their waterfront and pay close attention to the HAB reports in their area in an effort to make informed decisions on their drinking water source. With the increased reports of algae in the southern half of the lake, where there are private water supply systems- individuals need to be cautious and work with their water treatment system company to determine if their system will be sufficient.

Check out the following resources for more information:

On another note…. What about that lake foam?

If you spent any time on the lake over the last week, you may have noticed that we’ve had some significant lake foam! The foam is something we get asked about a lot, and studies over the years have contributed the foam to a breakdown in organic material (a die-off of plants, algae, zebra/ quagga mussels) which releases a surfactant in the water that is agitated by wave and wind action, causing the foam. More information can be found here.

Recently, CLWA launched a new lake foam research and we are actively working with a pair of researchers to further examine the composition of the foam being seen on the lake after HAB events. As a part of this study, several foam events will be sampled over the next few months, and we can use your help! We now have an online portal for the public to report foam observations, and we are beginning to log the frequency and extent of the foam. If you see a significant foam event and are able to take a photo, please consider uploading a report using the following link: Foam observations will be recorded for research purposes and the images coming in are being used to determine our sampling schedule.

As always, we appreciate all your eyes on the lake! Thanks for sending in reports and being an active part of our watershed community.

As we transition through September and into October, please continue to follow the recommendations of the NYS DEC and NYS Department of Health before recreating in the lake. Please remember that pets are especially vulnerable to harmful algae blooms. Check out the DEC photo gallery for examples of what to look for with blue green algae.

The maps that are generated from the shoreline monitoring program and the DEC’s NYHABS page show the most current HABs reports.

Questions? Send to

Kevin Olvany Lindsay McMillan Watershed Program Manager Association Director Canandaigua Lake Watershed Council Canandaigua Lake Watershed Council

More Information on Blue Green Algae

Click below for our Harmful Algae Bloom brochure.

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