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  • Terry Gronwall

Monday July 11th, 2022 Honeoye Lake Water Quality

Surface Water Temperature: ~76.8 F

Water Clarity: ~9.8 Feet

Lake Level: 802.9 Feet above sea level

Lake Level Relative to Weir: -0.6 Feet

Observations: Monday (7/11/22), The water clarity has decreased ~1.0 feet to ~9.8 feet and the surface water temperature has increased ~0.2 F to ~76.8 F over the last week. The lake is strongly stratified between 20-23 feet of depth today.

There was light to heavy algae visible in the water column at most of our HAB monitoring locations. It looks like green dots in the water column. We did see isolated areas with surface algae scum. See surface water picture on the left.

We took the image of today’s Anabaena and Gloeotrichia algae samples on the left using a high-powered microscope. Gloeotrichia blooms usually start in mid-June in Honeoye Lake. Gleotrichia gets its nutrients directly from the bottom sediments rather than from the nutrients in the lake water. For more information on Anabaena and Gloeotrichia see the articles at HARMFUL ALGAL BLOOMS | Honeoye Lake ( or search the internet for information.

We also found Copepods. Copepods are small crustations that inhabit freshwater water bodies. They are important members of the aquatic food web. They feed on microscopic algae cells and are food for small fish.

The DEC recommends that you, your family, and pets avoid contact with water that contains a blue-green algae bloom like Anabaena and Gloeotrichia. Everyone should be very careful to watch for blue-green algae blooms for the next few weeks.

Today (Monday 7/11/22) the lake is strongly stratified between 6-7 m (~20-23 feet) of depth. You can see this by the lines on the graph diverging again. The two data trends to watch are the rapidity increasing water temperature at all water depths and that the dissolved oxygen at 9 meters (30 feet) stays above 1 mg/L. When the dissolved oxygen level goes below 1 mg/L the phosphorus/iron bond will start to break releasing phosphorus into the deep water below the thermocline potentially providing fuel for a blue-green algae bloom later this summer. Dissolved oxygen at 7 m (~23 feet) today was 0.91 mg/L. This means that the phosphorus iron bond in 7 m (~23 feet) of water will be weak potentially releasing phosphorus into the water column. About 550 acres of the lake bottom is 7 m (~23 feet) or deeper. This is a significant amount of bottom area to potentially be releasing phosphorus into the deep water. Surface water temperature was ~76.8 F and bottom water temperature was ~69.3 F. 1-meter equals 3.3 feet.

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:


We made aquatic vegetation maps of the North and South Lake Basins on July 6 & 7, 2022. We found the aquatic vegetation to be extremely light (Red means aquatic vegetation growing to the surface) for this time of year. See our early July 2022 Aquatic Vegetation maps below:

You can see how the aquatic vegetation growth in early July 2022 compares with early July 2021 and 2020 at the link below:


The Town of Richmond has obtained an emergency DEC permit to dredge the shale and sediment deposits out of Mill Creek from just behind the Mill Creek Café to the 20A bridge and under the 20A bridge in the NYS DOT Road right away. Last week (Week of July 5th) they removed the shale and sediment from under the 20A bridge and North along the library parking lot. This week they plan to remove more shale and sediment in Mill Creek from the 20A bridge to several hundred yards south of the Mill Creek Café. See attached pictures. This project should reduce flooding risk from Mill Creek in the Hamlet and lessen the negative impact Mill Creek is having on the Outlet Creek flow. Richmond is working on a long-range plan to address other stream flow issues in the Outlet Creek and Mill Creek. We will keep you posted.


- Click on this link for the Winter 2022 HLWTF Newsletter:


- Click on this link to see the new HLWTF Honeoye Lake Watershed Storm Water Took Kit if you are planning any storm water projects on your property:

- Click on this link for "Honeoye Lake: 2021 State of the Lake article":

Draft Aeration Planning Project Report, Public Information Meeting Presentation, and WebEx recording posted on the HLWTF web site:


Click on the blue outlined box that says "Log in / Sign up" in the upper right-hand corner of this page to sign-up to be notified when we update our weekly Honeoye Lake water quality blog.


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