Monday September 14, 2026 Honeoye Lake Water Quality

Terry Gronwall

6 minutes ago

3 min read

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There were 3 new blue-green algae bloom reported to the DEC NYHABS site over the last week.

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Monday September 14, 2026 Honeoye Lake Water Quality

Surface Water Temperature: ~72.5 F

Water Clarity: ~6.6 Feet

Lake Level: 803.4 Feet above sea level

Lake level is at 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: Monday (9/14/26), Water clarity was ~6.6 feet a small increase of ~0.3 feet (~3.6 inches) since last week. Today’s water clarity was ~0.4 feet higher than it was on September 14, 2025. The surface water temperature was ~72.5 F about a 1.8 F decrease over the last week. The lake is in a very typical September water quality pattern this year. This morning had a partly cloudy sky with a moderate north wind.

There have been 24 Honeoye Lake near shore blue-green blooms reported to the DEC NYHABS site since June 29. There were 3 new blue-green algae bloom reported to the DEC NYHABS site over the last week. The 5 blue-green algae blooms reported to the DEC NYHABS site over the last 2 weeks are dark blue in color. 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 7.02 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 will be posted on the left tomorrow. Check back tomorrow to see the graphs.

Honeoye Lake completely mixed again in the last few days. The lake is isothermal meaning the water temperature is almost uniform from the surface to the bottom. The dissolved oxygen is well mixed too. Ranging from 8.06 mg/L at the surface to 7.02mg/L near the bottom. Since the dissolved oxygen near the lake bottom has stayed well above 0.5 mg/L for the last several weeks this mixing event should not fuel an increase in blue-green algae blooms.

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