Sunday September 6, 2026, Honeoye Lake Water Quality

Terry Gronwall
1 hour ago
3 min read

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There were 2 new blue-green algae bloom reported to the DEC NYHABS site over the last week due to the recent lake mixing event.

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Surface Water Temperature: ~74.3 F

Water Clarity: ~6.3 Feet

Lake Level: 803.3 Feet above sea level

Lake level is very close to weir level. Evaporation will lower the lake level 0.1 to 0.4 inches per day from this level unless we get more rain soon.

Observations: Sunday (9/6/26), Water clarity was ~6.3 feet the same as last week. An overcast sky reduced the water clarity a little bit. Today’s water clarity was ~2.3 feet higher than it was on September 8, 2025. The surface water temperature was ~74.3 F about a 1.6 F increase over the last week. This morning had an overcast sky with a light NW wind.

There have been 21 Honeoye Lake near shore blue-green blooms reported to the DEC NYHABS site since June 29. There were 2 new blue-green algae bloom reported to the DEC NYHABS site over the last week due to the recent lake mixing event they are the dark blue circles. See the Honeoye Lake DEC NYHABS Honeoye Lake map below:

We are now in the peak blue-green algae bloom time period across all of the Finger Lakes. The dark blue circles are booms reported in the last two weeks. See Finger Lakes DEC NYHABS map below:

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://experience.arcgis.com/experience/e5dec19912454731a308bbb7af605fb3/

We found about the same amounts of Anabaena (Dolchospermum) (looks like a spring or chain of beads), Microcystis (looks like a group of small round cells), Limnoraphis (looks like a rod), and Aphanizomenon (looks like a leaf) again today. See algae images on the left and below: You should be watchful for Anabaena, Microcystis, Limnoraphis, and Aphanizomenon blooms, all cyanobacteria species, lake wide over the next few weeks particularly when we have 80-90 F days with calm winds. More information on Gloeotrichia and Anabaena which are cyanobacteria can be found at: https://www.honeoyelakewatershed.org/habs

Several research studies have found that most of the phosphorus that fuels Honeoye Lake’s blue-green algae blooms is released from the lake bottom sediments when the lake’s dissolved oxygen level goes below 0.5 mg/L in the deeper parts of the lake breaking the phosphors/iron bond in the bottom sediments releasing phosphorus into the water column. The dissolved oxygen (DO) level near the lake bottom at 9 m (30 feet) was 2.77 mg/L today. This means that additional phosphorus is not currently being released from the lake’s bottom sediments at this time. Today’s temperature and dissolved oxygen graphs are posted on the left.

The lake is starting to restratify as you can see in the above temperature and dissolved oxygen graphs. The lake will either completely restratify by next week and the water near 8-9 m will have a dissolved oxygen level of less than 0.5 ug/L and start releasing phosphorus again or we will get a strong north or south wind mixing the lake. Please check back next week to see what happened.

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