• Terry Gronwall

August 3, 2020 Honeoye Lake Update (Click Here)

Surface Water Temperature: 80.0 F

Water Clarity: 8.2 Feet

Lake Level: 803.2 Feet above sea level

Lake Level Relative to Weir: -0.3 Feet

Observations: Monday (8/3/20), lake is in excellent condition for early August. There was only very light Gloeotrichia (blue-green algae) visible in the water column. We did not see any surface algae scum in near shore areas. However, we had an isolated near shore Gloeotrichia bloom reported to us in the NE corner of the lake late this afternoon. See picture below:

Gloeotrichia is a species of blue-green algae that gets its nutrients directly from the bottom sediments.

Water clarity has decreased by 8.6 feet to 8.2 feet since last week due to last week’s rain storm. This is very normal water clarity for early August (Water Clarity ~8 Feet). Surface water temperature declined slightly to 80.0 F.

The lake is now very “weakly” stratified and the water near the bottom below the thermocline has very low dissolved oxygen (anoxic). This means that the phosphorous/iron bond in the bottom sediments will weaken releasing phosphorus into the water near the bottom. The next time we get a North or South wind of 15-20 MPH we may have a lake mixing event that will mix this phosphorus into the whole water column top to bottom providing fuel for a blue-green algae bloom.

The lake has gone from being strongly startified to weakly stratified over the last month. On July 9th there was 7 degrees C difference between surface and bottom water temperature. On August 3rd there was only 2.5 degrees C difference between surface and bottom temperature. The larger the temperature differential the higher the lake’s resistance to mixing.

You can see that on our water temperature graph to the left.

1 meter (m) = 3.3 Feet and 1 Degree Centigrade ( C ) = 1.8 Fahrenheit (F)

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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Honeoye Lake Watershed Task Force Members:

Town of Richmond

Town of Canadice

Town of Bristol

Town of South Bristol

Town of Naples

Honeoye Valley Association