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  • Terry Gronwall

Monday July 26th 2021 Honeoye Lake Water Quality

Surface Water Temperature: 76.6 F

Water Clarity: 9.5 Feet

Lake Level: 803.5 Feet above sea level

Lake Level Relative to Weir: 0.0 Feet

Observations: Monday (7/26/21), The water clarity has increased by ~6 feet over the last week to 9.5 feet and the surface water temperature has decreased ~1.3 degrees Fahrenheit to 76.6 Fahrenheit. There was light Gloeotrichia and Anabaena visible in the water column in most areas of the lake this morning. We did see Gleoetrichia surface scum at 10 AM due to a sunny sky and calm wind at our open water sampling site. When we have a sunny sky and calm wind algae raises to the surface and produces a scum. By 11 AM at the same location when a light breeze developed the surface scum disappeared. See our pictures taken at 10 AM and 11 AM at this site below:

We took the image of today’s algae sample to the left using a high-powered microscope. Gloeotrichia is very large with sharp points and the Anabaena is smaller and looks like a coiled wire. For more information on Gloeotrichia and Anabaena 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.

Today, July 26th, the lake remains stratified releasing legacy phosphorus from 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. See DO chart where 7-9 m have a DO less than 1.

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 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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