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  • Terry Gronwall

Monday August 2nd 2021 Honeoye Lake Water Quality

Surface Water Temperature: 73.9 F

Water Clarity: 9.75 Feet

Lake Level: 803.5 Feet above sea level

Lake Level Relative to Weir: 0.0 Feet

Observations: Monday (8/2/21), The water clarity has remained constant over the last week at ~9.75 feet and the surface water temperature has decreased ~2.7 degrees Fahrenheit to 73.9 Fahrenheit. There was light Gloeotrichia, a blue-green algae species, visible in the water column in most of the lake this morning. We did not see any algae surface scum. It was a beautiful day to enjoy Honeoye Lake.

We took the image of today’s algae sample to the left using a high-powered microscope. We again found only Gloeotrichia present. For more information on Gloeotrichia see the articles at HARMFUL ALGAL BLOOMS | Honeoye Lake (

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

The lake mixed down to 8 m last Thursday July 26th. It was still well mixed down to 8 m today Monday August 2nd, 2021. When the lake mixed last Thursday, it mixed some bottom water with phosphorus released from the bottom sediments into the whole water column. However, we haven’t seen signs of a new major blue-green algae bloom yet. Probably due to the cooler weather we have been having. Monday August 2nd surface temperature was 73.9 F and bottom temperature was 72.3 F.

When the lake stratifies again at ~7 m legacy phosphorus will be released from a significant area of the bottom sediments all over again. 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.

We collect the temperature and dissolved oxygen (DO) data for the chart above twice a week using a YSI Temperature and Dissolved Oxygen meter. We lower the meter probe on a cable marked every meter and stop every meter of depth to take Temperature and Dissolved Oxygen readings. Then the graphs are created from this data that we collect manually.

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:

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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:

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

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

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

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