presenter at the 2019 Water Quality Forum in Geneva, NY

5 Key Takeaways from the Seneca Lake Water Quality Forum

On Wednesday, October 23, our team attended the Water Quality Forum at Hobart and William Smith Colleges to review research collected in 2019 and discuss water quality issues important to Seneca Lake. While harmful algae blooms (HAB’s) continue to be a serious issue facing the region, there are a number of state and local organizations collecting valuable data and funding projects to fight HAB’s in the Finger Lakes.

Each year, more is understood about blue green algae and what we can do to reduce bloom frequency and toxicity. Here are 5 takeaways from the forum and the research conducted during the 2019 HAB season: :

Suspected Blue Green Algae Bloom in Seneca Lake

85% of HAB’s sent out for testing this year came back positive for high toxin levels.

Over 100 samples from suspicious algae blooms were collected this year, and of those samples, 40 were budgeted to be sent out for toxin level measurement.  34 were positive for high toxins, driving home the point that if you see or suspect a bloom, stay out of the water.

HAB’s are most toxic at 20⁰ C, the water temperature we see most often in September. In 2018, the last algae bloom was reported toward the end of September, but this year, blooms have been confirmed late into October, a result of extra sunshine and warmer water temps. Generally, HAB’s are not an issue until late August on the majority of the lakes.

It cannot be determined if HAB’s are increasing year over year.

While the data presented since 2012 indicates that HAB’s are not only increasing in frequency, but also in toxicity, the DEC cannot conclude that this is the case. In 2018, there were 120 shoreline volunteers photographing blooms and collecting samples. Just 5 years earlier, a hotline was the only public initiative and no training was conducted to identify blue green algae. Aimee Clinkhammer, researcher with NYS DEC, concluded that the trend could be heavily influenced by the increase in education and conversation surrounding HAB’s.

There’s something in the soil on Seneca.

In an experiment performed by John Halfman, researcher for the Finger Lakes Institute, mud was collected in various locations along the Seneca Lake shoreline. Geneva tap water was added to the samples. They were left undisturbed and received daily sun, replicating favorable HAB conditions. Over time, every sample developed a blue green algae bloom.

John Halfman’s soil experiment presentation slide

It’s known that HAB’s need nitrogen and phosphorus to proliferate. These nutrients enter the lake in greater quantities after storms through stream runoff. Another nutrient source could be decaying macrophytes along the shore, like dried up seaweed and tree branches. To reduce the amount of shoreline debris settling in the water, Halfman urged attendees to perform routine beach clean up, especially after storms.

The uniqueness of each lake may impact how and when HAB’s form.

While the forum focused on Seneca Lake, the other Finger Lakes were not ignored. In comparing trends found on Seneca to the other 10 lakes, there were few parallels. Some lakes had higher levels of phosphorus with some bloom activity, like Seneca. Other lakes had very low levels of phosphorus and high bloom activity, like Skaneateles Lake. This indicates that different Finger Lakes may be able to handle different nutrient levels and, therefore, be impacted by HAB’s in unique ways.

New York is a leader in the national effort to address HAB’s.

HAB’s are not exclusive to the Finger Lakes, and are an even greater issue downstate and across the country. We are not alone, but we are the model. Clinkhammer commented that other state agencies have looked to the NYS DEC for guidance in forming their own HAB’s initiatives and programs.


While more research is needed to fully understand and address HAB’s in our region, the Water Quality Forum provided insight into the fight and hope for the future of our lakes.

A huge thank you to the Seneca Pure Waters Association for holding this important and well attended event! We look forward strengthening our partnership and keeping our homeowners and guests informed.

For more information about harmful algae blooms, please visit the NYHABS website.

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