Hydrilla in Cayuga Lake

(July 2016) — Hydrilla, an extremely aggressive aquatic plant, was found in the Cayuga Lake Inlet in Ithaca in early August 2011. National experts on Hydrilla and local resource managers/stewards agree that an approach including the use of herbicides is the best method to achieve eradication of Hydrilla.

Total eradication is a long-term process; however the treatment over the past five years has been very successful, resulting in a dramatic reduction in the number of rooted Hydrilla plants and ungerminated tubers now being observed.

This has brought about some strategic changes in the 2016 management activity. Locating Hydrilla plants now requires more intensive plant monitoring but less herbicide is needed in the Inlet and Fall Creek, as compared with previous years. In addition, the rare Hydrilla that may be found in the Lake itself this season will be addressed by hand removal of the plants and placement of benthic barriers over the affected areas of the lake bed, conducted by divers where necessary. (Like herbicide application, hand removal of Hydrilla plants is conducted under permit from the NYSDEC.)
 

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2016 Monitoring Results and Information »

2015 Monitoring Results and Information »

2014 Monitoring Results and Information »

2013 Endothall Application, Fall Creek

PDF Downloads: Monitoring Results  |  Health Effects Information  |  Treatment Map

Following the discovery in August of the invasive aquatic plant Hydrilla in the lower reaches of Fall Creek, the Tompkins County Soil and Water District, representing the Hydrilla Task Force, applied for a DEC permit to apply Aquathol K (active ingredient: 40.3% Dipotassium Salt of Endothall) in Fall Creek. This is the same herbicide that was previously applied in the Cayuga Inlet.

The treatment area is in Fall Creek, downstream (west) of Rt 13/34. A total of 22 acres is being treated on September 26, 2013. Water quality monitoring will be conducted for two to three weeks after the treatment, with the sampling results reported here.

Fluridone Application, 2013

PDF Downloads: Monitoring Results  |  Health Effects Information  |  Treatment Map

Fluridone, a selective systemic herbicide, is the second part of the 2013 Hydrilla treatment strategy in Cayuga Inlet. The chemical is delivered by continuous drip metering equipment at three upstream locations (map), and by a deployment of pellets in shallow water areas (map) as needed at approximately monthly intervals, with the intention of maintaining a concentration of 3-5 ppb (parts per billion) of fluridone in the inlet for at least 30-90 days.

Endothall Application, 2013

PDF Downloads: Monitoring Results  |  Health Effects Information  |  Treatment Map

Water quality monitoring is conducted during the herbicide application periods. Water samples are being collected in the treatment area and at selected sites in the lake, as well as at the Bolton Point water intake. Monitoring results are updated online each time new sampling results are available.

Fluridone 2012

Fluridone, a selective systemic herbicide, is the second part of the 2012 Hydrilla treatment strategy in Cayuga Inlet. The chemical is delivered by continuous drip metering equipment at three upstream locations (map), and by a one-time deployment of pellets in shallow water areas (map), with the intention of maintaining a concentration of 3-5 ppb (parts per billion) of fluridone in the inlet for at least 30-90 days.

Monitoring Results (PDF, 15KB, 17" x 11"; Final update 11/28/2012)

Health Effects Information (PDF, 80KB)

PDF Maps: Cayuga Inlet Treatment Area and Monitoring (PDF files, 8.5" x 11", 580KB each)

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Endothall Application, June 2012

PDF Downloads: Monitoring Results | Health Effects Information | Treatment Map

What is Endothall?

Endothall is a selective contact herbicide that has been applied to the Cayuga Inlet in the continued effort to eradicate Hydrilla. Endothall kills the growing green vegetation that it contacts in the water. Hydrilla is much more sensitive to the effects of endothall than most native plants.

The chemical is applied below the surface of the water. Licensed herbicide applicators Allied Biological deployed the chemical throughout the marked treatment area on June 26, 2012, completing the application in one day. The chemical degrades naturally by bacterial action in the water, and has a half-life ranging from 5 to 8 days.

Water samples are being collected in the treatment area and at selected sites in the lake, as well as at the Bolton Point water intake and distribution system entry point. The Monitoring Results spreadsheet is updated each time new sampling results are available. The New York State Drinking Water Maximum Contaminant Level (MCL) for endothall is 50 ppb (parts per billion); however, taking water directly from the lake for drinking is never recommended. Swimming was prohibited for 24 hours after the application, but there is no ongoing restriction.

Monitoring Results (PDF, 48KB; 8.5"x14")

Health Effects Information (PDF, 63KB)

Cayuga Inlet Treatment Area map (PDF, 807KB)