We noticed today, Thursday September 17th, 2020 that the lake had less algae in the water column and water clarity had increase by ~1.5 feet to 5.5 feet from last Monday 9/14 at our open water monitoring site. We did not see any algae surface scum today. This decrease in visible algae was due to this week’s colder weather and today’s overcast sky. However, there is still a of of algae in the water column, so if we get another weather pattern of 80+ F temperature, calm wind, and sunny skies, we could have a flare up of a blue-green algae bloom again. Most near shore locations we checked today looked like the pictures below, but some near shore locations in the Northern Lake Basin still had enough algae to be greenish in color :
Today, Thursday September 17th, 2020, the lake was still isothermal. Isothermal means the water column has uniform water temperature from top to bottom. The water temperature was ~1 degree C (~2 degrees F) colder than last Monday. The dissolved oxygen level is still relatively high and well mixed from top to bottom. This means that currently no additional legacy phosphorus is being released from the bottom sediments.
1 meter (m) = 3.3 Feet and 1 Degree Centigrade ( C ) = 1.8 Fahrenheit (F)
Because the Thursday August 20th mixing (turn over) event mixed nutrients released by the bottom sediments when the dissolved oxygen level was below 1 ug/L into the water column, we are likely to continue to have an Anabaena and Microcystis blooms until the lake water gets substantially below 75 F (24 c). An Anabaena bloom looks like pea-soup and an Microcystis bloom looks like green paint on the lake surface. Anabaena and Microcystis blooms have the potential to produce toxins that could affect people and their pets. Therefore, be extra watchful for new blue-green algae blooms for the rest of the summer. Please report any suspicious blooms to us at
watershedtaskforce@gmail.com and the NYSDEC “Know it, Avoid it, Report it” at https://survey123.arcgis.com/share/66337b887ccd465ab7645c0a9c1bc5c0
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:
September 14, 2020 Honeoye Lake Update (Click Here)
Surface Water Temperature: 70.0 F
Water Clarity: 4.0 Feet
Lake Level: 803.4 Feet above sea level
Lake Level Relative to Weir: -0.1 Feet
Observations: Monday (9/14/20), lake is still experiencing a lake wide blue-green algae bloom due to the nutrients that were mixed in the water column on Thursday 8/20 when the lake had its traditional late August lake mixing (turn over) event. There was medium to heavy Anabaena and Microcystis (blue-green algae) visible in the water column at most of our near shore and open water HABs monitoring locations. We did not see any algae surface scum because today the sky was heavily overcast and it was windy. However, there is still a lot of algae in the water column, so if we get another weather pattern of 80+ F temperature, calm wind, and sunny skies, we could have a flare up of a blue-green algae bloom surface scum again. All near shore locations we checked today looked like the pictures below:
Anabaena and Microcystis are a species of blue-green algae that we see starting usually after a lake mixing (turn over) event. Anabaena and Microcystis have the potential to produce toxins that can be harmful to people and pets. We strongly urge you to follow the DEC guidelines of “Know it, Avoid it, Report it” For more info go to: https://www.honeoyelakewatershed.org/habs
Water clarity was 4.0 feet the about the same as last week. This is lower than normal water clarity for late August (Water Clarity Ave. ~6.6 Feet) due to a moderate to heavy amount of algae in the water column. Surface water temperature declined about 2.0 F to 70.0 F. Lake level was 803.4 feet above sea level about the same as last week.
Today, Monday September 14, 2020, the lake was still isothermal due to the cooler fall air temperatures we have been having over the last week. Isothermal means the water column has uniform water temperature from top to bottom. The dissolved oxygen level was also relatively high and well mixed from top to bottom in the water column. This means that currently no additional legacy phosphorus is being released from the bottom sediments given the relatively high dissolved oxygen level near the bottom.
1 meter (m) = 3.3 Feet and 1 Degree Centigrade ( C ) = 1.8 Fahrenheit (F)
Now that the lake has mixed (turned over), we are likely to have Anabaena and Microcystis blooms until our cooler fall weather significantly lowers the water temperature. An Anabaena bloom looks like pea-soup and a Microcystis bloom looks like green paint on the lake surface. Be extra watchful for new blue-green algae blooms for the rest of the summer. Please report any suspicious blooms to us at watershedtaskforce@gmail.com and the NYSDEC at https://survey123.arcgis.com/share/66337b887ccd465ab7645c0a9c1bc5c0
Blue-green algae's optimum water temperature for growth is 75 F (24 c) and warmer. Once the water temperature starts falling below 75 F (24 c) the algae's growth rate starts to slow. Then the bloom slowly dissipates as the water temperature declines in the fall. You should watch our weekly water temperature trend for the lake getting colder and water clarity increases to signal that this blue-green algae bloom is starting to dissipate. The water temperature is starting to drop a couple degrees Fahrenheit per week, but the water clarity has not started to increase yet meaning the blue-green algae bloom that started a few weeks ago has not started to dissipate yet. We will keep you posted on these indicators.
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: