Eradication Project in Aurora

During the summers of 2017 through 2020, the U.S. Army Corps of Engineers (USACE), Buffalo District, has worked on a project aimed toward the eradication of hydrilla from a portion of Cayuga Lake adjacent to the Village of Aurora. This treatment has been successful in reducing the amount of hydrilla by approximately 99%, but areas of hydrilla are still present.

The USACE is continuing this project in 2021, and will treat the two main areas where hydrilla has been found with the application of Fluridone and treat some small patches of hydrilla with Harpoon Granular, a copper based herbicide. It is anticipated that the treatment during the summer months will continue for a number of years.

Click here to see the SUPPLEMENTAL "Waterfront Owner/User Notification Letter for the Use of an Aquatic Herbicide on Cayuga Lake, Aurora, New York." and REVISED  2021 Hydrilla Treatment Areas."

Click here to see the "Waterfront Owner/User Notification Letter for the Use of an Aquatic Herbicide on Cayuga Lake, Aurora, New York."

Click here to see the "Cayuga Lake at Aurora, New York Control Demonstration Project" 2021 brochure.

Click here to see the "Post-Treatment Assessment for Aquatic Plant Control ERDC Demonstration Project Wells College Bay, Cayuga Lake 2020."


National and local experts on hydrilla agree that the use of herbicides is the best method to achieve eradication of hydrilla. The USACE will apply Fluridone in a slow release pellet form, trade name Sonar H4C, in two primary treatment areas.  The Northern treatment area is approximately 10 acres along 1,500 linear feet of shoreline between Wells College Dock and north of Wells Road and the Southern treatment area is approximately 40 acres along 3,700 linear feet of shoreline between Wells College Water Plant and south of the outlet of Paines Creek.    The Sonar H4C application will be applied as a total of ten treatments between June and August and is targeted to begin the week of June 27, 2021.  

A granular copper-based herbicide, tradename Harpoon Granular, will be used to spot treat small areas of hydrilla that are outside of the main treatment area. It will be used to spot treat approximately 5 acres, likely the week of August 8, 2021 if necessary.

The herbicide products will be applied by a New York State licensed professional applicator.

Water Restrictions

At the levels at which the Fluridone or Harpoon Granular will be applied, there will be no restrictions on drinking, fishing, swimming, boating, or domestic use of treated water. There may be some restrictions on watering certain plants with Fluridone treated water.

Wilson’s Disease

People with Wilson’s Disease have increased sensitivity to copper and should consult their physician regarding the application of Harpoon Granular and any precautions that should be taken.

Water Monitoring

The Cayuga County Health Department will conduct water quality monitoring of the public drinking water and the public bathing beach, when the beach is open, during this treatment period. View 2021 sampling results when they become available as well as previous year’s results (2018 sampling results,  2019 sampling results and 2020 sampling results).

Hydrilla Plant