No Adverse Effects From Herbicide Applications

Herbicide applications on Chautauqua Lake this summer did the job they were designed to do with little harmful side effects to people or native plant species.

Princeton Hydro, the third party monitoring company hired by the Chautauqua Lake and Watershed Management Alliance, released its report Tuesday via the alliance’s website. Overall, the study states, the treatment was successful while data showed adverse impacts to be minimal. The hiring of a third party to monitor this summer’s herbicide application on Chautauqua Lake was one of the key tenets of the Memorandum of Agreement pieced together by County Executive George Borrello.

“My big takeaway is that it appears that the herbicide treatments did their job in the places they were supposed to,” Borrello said. “Although there was appearance of some drift in some places, that seemed to fall well within predicted guidelines from what I can tell. That was what was told to us at the alliance board meeting. It also speaks to the fact that we put this line in place of no herbicide treatment north of Long Point to allow for the margin, so to speak, for the drift that would still not have an impact on sensitive areas and drinking water resources. So I think that the results report true that the line was not only good for us to get consensus around the lake but it was also a responsible point to ensure safety of herbicides.”


Chautauqua Institution, the Chautauqua Lake Association and the Chautauqua Lake Fishing Association had expressed concerns over potential drift of herbicides out of the application areas and into drift and control zones. Princeton Hydro’s report states chemical data showed some drift of herbicide outside of treatment areas into the drift and control zones seven to 14 days after the treatment, but the report noted such drift is not surprising in a lake environment due to the solubility of the chemicals and inability to discretely cordon off water flow into and out of treatment areas. The report states the routine monitoring of potable water intakes, with restrictions to be lifted after testing negative, is a prudent approach for ensuring the health of consumptive users and should continue as an added layer of precaution.

The report states there were also potential impacts to native submerged aquatic vegetation at two drift stations, which noted a marked reduction in biomass of elodea and water stargrass, respectively. Princeton Hydro officials recommend further evaluation of potential herbicide drift and its dynamics, including possible northward drift, by collecting additional paired macrophyte and chemical samples to not only assess presence/absence of chemical drift but also significance as it relates to impacts on macrophyte growth.

While noting some evidence of drift and a desire for further study of drift dynamics on Chautauqua Lake, the report also made clear that post-treatment samples collected by water supply operators and earlier collections by Princeton Hydro and Solitude (the company that applied the herbicides) showed the herbicide treatment did not result in unacceptable levels of herbicides reaching the lake’s two public water supplies.

Borrello said there are plans to continue third party monitoring next year as is called for by the Memorandum of Agreement.

“Certainly going into next year we’ll continue with the consensus strategy which calls for independent monitoring,” Borrello said. “There is studying they want to do beyond the Memorandum of Agreement, but certainly we’ll be doing independent monitoring going into next year to be in compliance with the Memorandum of Agreement. I think that’s certainly a good takeaway for people.”


Plant biomass changed overall with decreases noted in the targeted invasives Eurasian watermilfoil and curlyleaf pondweed. These decreases were not statistically significant but were sizeable both for plant biomass overall and for curly-leaf pondweed. Eurasian watermilfoil also generally decreased but was not present in sizeable densities prior to treatment as was the case with curly-leaf pondweed. The treatments did exert control over the targeted species of concern: Eurasian watermilfoil and curly-leaf pondweed.

One of the reasons Eurasian milfoil was not as impacted by the herbicides as would be expected was that milfoil was already low before the herbicides were applied.

As was noted earlier this year with the resurgence of eel weed in North Harmony, native vegetation increased after the herbicide treatments in both diversity and number.

“Between pre- and post-treatment conditions, curly-leaf pondweed displayed a statistically significant decrease in the treatment areas while Eurasian watermilfoil also displayed a decrease but this was not statistically significant,” the report states. “In contrast, four of the more common native species all increase from pre- to post-treatment conditions.”


Borrello will present his 2020 executive budget proposal today in Mayville. The Memorandum of Understanding and consensus strategy includes the desire to create a comprehensive Chautauqua Lake management strategy that would include harvesting, near shore cleanup, watershed activities to reduce phosphorus and herbicide use. Princeton Hydro’s report should put at ease some concerns expressed over the past few years about the use of herbicides on the lake, Borrello said, though the Memorandum of Agreement may face more tests over the fall and winter months.

“I think going into next year, we’re going to have a few pieces trying to jockey for position and work against the unity that we have right now around Chautauqua Lake,” Borrello said. I think ultimately the people of this county, particularly the people who are so heavily invested in Chautauqua Lake, like what they saw this year. That’s the response I heard, and that they want to see it continue into 2020. I will work hard to make sure it continues no matter what position I might hold.”

While officials are still working on a lake strategy and to hold together the 2019 consensus, Borrello said the county also needs to find a funding stream so that there is a way to pay for the treatment plan.

“Well, without stealing any thunder, the county is going to continue to do its best to provide what I refer to as bridge funding to bridge the gap between where we are now and where we hopefully will be in the event of the legislature’s adoption of a lake district sometime in the future,” Borrello said. “We will continue to try to support this on what we hope is a temporary basis because the funds we’ve used the past have come out of reserve. Obviously, the piggy bank is only so big. We’ll look forward to whether it’s a lake protection district or some other consistent form of funding, and continue to try to work hard to fill that gap so we can come up with that consistent source of funding.”

Borrello also made clear he is looking for sources of funding that aren’t from local taxpayers. The resignation of former state Sen. Catharine Young, R-Olean, and her position of importance on the Senate Finance Committee hampered efforts to secure state funding for Chautauqua Lake initiatives. The county executive said the county is looking for funding that isn’t dependent on political connections.

“There are other sources of funds at the state level,” Borrello said. The DEC has some funding to address water quality issues. We’re working hard at the federal level as well. Certainly, going back to the announcement of the $65 million to address harmful algal blooms in 12 lakes throughout the state, Chautauqua Lake being one of them, that’s another sources of money. We have yet to see any of that money disbursed, so we need to go back and hold the governor accountable for the money he announced more than a year ago.”


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