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  • Terry Gronwall

Monday September 20 2021 Honeoye Lake Water Quality

Updated: Sep 23

Surface Water Temperature: 71.4 F

Water Clarity: 5.5 Feet

Lake Level: 803.5 Feet above sea level

Lake Level Relative to Weir: +0.0 Feet


Observations: Monday (9/20/21), The water clarity has increased ~0.25 foot to 5.5 feet and the surface water temperature has decreased ~0.4 F to 71.4 F over the last week. There was Anabaena, Microcystis, and Lyngbya visible in the water column. The lake mixing event over Labor Day Weekend brought nutrients released from the bottom sediments to the surface which are still fueling a blue-green algae bloom. Open water had visible blue-green algae in the water column, but no surface scum. Looked good from a surface view (first picture below): A number of isolated near shore locations had blue-green algae surface scum (second picture below):



We took the images below of today’s Anabaena (looks like a coiled spring), Microcytes (looks like a blob of cells), and Lyngbya (looks like a long straight filament) algae samples using a high-powered microscope. You can Google Anabaena, Microcystis, Lyngbya to learn more about them. For more information on Anabaena and Microcystis see the articles at HARMFUL ALGAL BLOOMS | Honeoye Lake (honeoyelakewatershed.org)



The DEC recommends that you, your family, and pets avoid contact with water that contains blue-green algae bloom like Anabaena Microcystis, and Aphanizomenon. Everyone should be very careful to watch for blue-green algae blooms for the next few weeks.


The lake mixed again over Labor Day Weekend (9/4 & 9/5). The lake was still will mixed today (9/20). You can see the lake mixing event on our temperature and dissolved oxygen charts to the left. The temperature and dissolved oxygen at every depth becomes uniform and the lines on the graph converge. When the lake mixed on 9/4-9/5 it mixed some bottom water with phosphorus and ammonia released from the bottom sediments into the whole water column. This has fueled the blue-green algae bloom that we are experiencing at this time. This blue-green algae bloom will likely continue until we get much colder fall weather. Surface water temperature 71.4 F. Bottom water temperature 71.0 F.

When a lake stratifies and forms a thermocline the decaying organic matter, dead algae and weed fragments, on the lake bottom consumes dissolved oxygen (DO) in the water below the thermocline. When the DO has been completely consumed the phosphorus iron bond in the bottom sediments becomes weak releasing legacy phosphorus into the water near the bottom sediments.

Always use your own visual assessment before making contact with the lake water at this time of year as the blue-green algae situation can change daily if not hourly. Please regularly check the DEC HABs alert map for more detailed updates on Honeoye Lake HABs alerts:

https://nysdec.maps.arcgis.com/apps/webappviewer/index.html?id=ae91142c812a4ab997ba739ed9723e6e


Click on the blue outlined box that says "Log in / Sign up" in the upper right hand corner of this page to sign-up to be notified when we update our weekly Honeoye Lake water quality blog.


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- Click on this link to see the new HLWTF Honeoye Lake Watershed Storm Water Took Kit if you are planning any storm water projects on your property:

e6fc30_5299c36614ab4b3b995b53aeec724bfa.pdf (filesusr.com)


- Click on this link for "2021 Honeoye Lake Aeration Engineering Planning Project"

Aeration Engineering Grant | Honeoye Lake (honeoyelakewatershed.org)

- Click on this link for HLWTF Winter newsletter: e6fc30_ef8d01223f42408ba11b3a7a5f83bebe.pdf

- Click on this link for "2020 Water Quality: What, Why, What's Next"

SCIENTIFIC RESEARCH | Honeoye Lake (honeoyelakewatershed.org)








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