Welcome to the final Friday Water Quality Update of the season.


Last week, we reported on a significant bloom event that started on Monday, October 4th - occurring mostly on the west of the lake, which then intensified by Wednesday, October 6th to a lake-wide bloom event. We are sharing results from last week's samples collected by volunteers below. These samples all came back well above the bloom threshold of 25 micrograms per liter of blue green chlorophyll (ug/L) and had the highest levels of the season.


Since last week’s significant bloom event, activity had (for the most part) calmed down, although with yesterday's calm conditions, 8 bloom reports were filed (Thursday, 10/14). Three samples were collected from the east side of the lake yesterday - in Crystal beach, Cottage City, and Vine Valley. All showed significant concentrations of algae.



We want to stress that although we are well into October, there is still the potential for cyanobacteria to reach bloom levels when conditions are right. Sunny or not - on calm days we have been seeing surface accumulations of HABs. From our sampling efforts, we know that when you see surface accumulations of HABs, the levels are high and these blooms have the potential to be harmful to both human and pet health. Please continue to avoid these areas and do not let your pets swim in water that is discolored, showing surface streaks of algae, or has “pea soup” like conditions.


Although this is the final scheduled weekly water quality update, monitoring will continue through a combination of volunteer and watershed staff efforts. We are also staying connected with the water purveyors to learn of any potential drinking water impacts from harmful algae blooms. Routine monitoring of the municipal drinking water systems continues to show that the treated drinking water is safe to drink. The latest weekly results can be found here.


We thank our many CLWA volunteers for their continued support and efforts to monitor the lake in this extended season. You will be hearing more from CLWA and our partners in the future as we put together our season-end report. The Canandaigua Lake Watershed Council will also be hosting a public meeting to share information about the latest efforts to update our current Watershed Plan to meet the DEC requirements for a 9 Element Watershed Plan later this fall / early winter. More information on that event will be coming out in the future.


As always, we encourage you to follow our reports on our website, and on the facebook page for further information.


For those interested in learning more about the formation of HABs and the latest HABs research, consider attending the Harmful Algal Bloom Symposium hosted by the Finger Lakes Institute, NYS DEC, SUNY Fredonia, and Corning on October 28th. More information is posted HERE.




Lakewide Bloom Event on Canandaigua Lake

Many areas around the lake impacted by harmful algae blooms


This week, we experienced a significant harmful algal bloom event on Canandaigua Lake. Blooms extended along the vast majority of the shoreline, as well as several areas mid-lake. Other nearby lakes also reported similar extensive bloom events the last few days, including Seneca, Keuka, and Cayuga.


As we reported earlier this week, thick concentrations of cyanobacteria (harmful algae blooms) were reported along the west side of the lake on Monday (10/4) and Tuesday (10/5). By Wednesday (10/6), volunteers, watershed staff, and lake residents were documenting extensive blooms along much of the 36 miles of shoreline. Heavy surface streaking of algae and “pea soup”-like conditions were observed, in some cases extending 100+ feet off the shoreline. Streaks were also documented in mid-lake areas extending up and down the lake. It was by far the most significant HAB event recorded this season, and was one of the more extensive bloom events we’ve observed since active HAB monitoring began in 2015. Please see the images and videos below.


However, overall clarity as measured by a secchi disk remains much better than what we were observing during the bloom events of 2015 and 2018. Clarity measurements are averaging about 6 meters in the lake this week. Whereas, during the bloom events of 2015 and 2018, clarity was in the 3 meter range. This is indicating that the overall biomass of cyanobacteria is less than the other major bloom years.


The late-season timing of this bloom event is a little surprising, given the recent cooler air and water temperatures and overcast skies, which are not typically favorable conditions under which HABs form. However, we did have very calm wind conditions for three straight days, which is a big factor in allowing cyanobacteria to multiply and concentrate at the surface. We also had a significant rain event Sunday 10/3 in the northern part of the watershed that does add nutrients to the system from the surrounding drainage areas. Finally, the natural ecosystem progression of the lake typically has cyanobacteria dominating the algal community at this time of year. As mentioned above- we were not alone in seeing significant blooms- several other Finger Lakes also experienced similar bloom events. We will continue to work with our state and local research partners to better understand these dynamics.


Although the Volunteer Shoreline HABs program officially ended on Sunday, many volunteers have been keeping a trained eye on the lake and using the online reporting system to keep us notified of blooms. 39 bloom reports were filed this week and 20 water samples collected. The first batch of results can be found below. Results for CyanoChlorophyll (measurement of blue-green algae) all showed very high levels. This further stresses the point - bloom areas need to be avoided as they have the potential to be harmful to both human and pet health.



Thanks to our many CLWA volunteers for their continued support and efforts to monitor the lake in this extended season. We also want to give a special shout out to Walton Point resident Martin (Marty) Gordon, who was able to get out during Wednesday’s bloom event to capture some incredible drone footage. Check out the videos below to get a bird’s eye view of both shoreline and offshore blooms around Walton Point, and the Canandaigua Yacht Club.


The forecast for the next 10 days looks like we may get a stretch of calm, sunny weather, so please continue to use your visual indicators and use extreme caution before recreating in the lake or letting pets swim.


As always, we encourage you to follow our reports on our websites, and on the Association's facebook page for further information.









Municipal Drinking Water Test Results


The City of Canandaigua, Town of Gorham, and the Village of Rushville had detectable levels of the microcystin toxin in the raw (untreated) water samples collected on Monday, 10/4. Samples collected of the finished drinking water (after treatment was applied) had non detectable levels of microcystin. Follow up sampling was performed on Thursday, 10/7 at the Gorham water treatment plant and results of raw and finished drinking water had non detectable levels of the microcystin toxin.


This sampling is part of the proactive routine microcystin testing that all 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) participate in for testing of both raw (untreated) and finished (treated) drinking water. Weekly results are posted on the CLWA website.


For more information, check out the HABs and Drinking water page on the CLWA website

Good Afternoon Everyone,


Although we are in-between our regularly scheduled Friday updates, we wanted to report that we have been seeing harmful algae blooms along the shoreline the last two days. Conditions have been relatively calm, but a subtle northeast wind means we have been getting reports predominantly on the west side of the lake. See photos below, captured today by volunteers.


With this recent change in shoreline conditions, it is strongly recommended to avoid areas where you notice discolored water, streaking of algae, surface scums, or “pea soup” like conditions. Please use caution before entering the water or letting pets swim in the lake. As recommended by the DEC, if you see it, avoid it.


At this point, these are not lake-wide blooms, and we have still been getting good clarity out in the open water by our secchi disk measurements. However, if winds stay calm and we see sunny conditions in the coming days, shoreline blooms may continue.


We will share more per our weekly Friday update, but we wanted to urge all recreational lake users to please use caution before recreating in the lake.




More Information on Blue Green Algae

Click below for our Harmful Algae Bloom brochure.

Featured Posts
Archive