Monday July 27, 2026 Honeoye Lake Water Quality

Terry Gronwall
17 hours ago
3 min read

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Due to rain forecasted for Tuesday July 28th there is still time to sign up for the next FL-PRSIM European Frogbit pull in the Honeoye Lake inlet on Wednesday August 5th. Details below:

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Surface Water Temperature: ~76.8 F

Water Clarity: ~8.6 Feet

Lake Level: 803.0 Feet above sea level

Lake level is a little below 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 (7/27/26), Water clarity was ~8.6 feet a decrease of about 2.0 feet over the last week. However, todays water clarity was ~3.0 feet higher than it was on July 25, 2025, when it was ~5.6 feet. The surface water temperature was ~76.8 F about a 0.9 F decrease over the last week due to the cooler weather we have been having. This morning had a calm wind with light wildfire smoke over the lake.

There have only been 10 Honeoye Lake near shore blue-green blooms reported to the DEC NYHABS site since June 29. There was one new blue-green algae blooms reported to the DEC over the last week located at the NYS Public Boat Launch site indicated by the dark blue circle. See the Honeoye Lake DEC NYHABS Honeoye Lake 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 no Gloeotrichia (lots of small spikes) today. Gloeotrichia has run its course and is no longer a concern. We also continued to find “small” 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) for the first time today. We also found a lot of

Ceratium (looks like a small space ship) which is not a blue-green species 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 ~8.5 m (~28 feet) was 0.38 mg/L today. This means that only a small amount of phosphorus is currently being released from the ~67 acres of 8.5 m and deeper bottom sediments into the deepest part of the lake water. If we do not have a complete lake mixing event soon this phosphorus will potentially fuel a blue-green algae bloom when the lake mixes later this summer. Today’s temperature and dissolved oxygen graphs are posted on the left.

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