Hydrilla Monitoring, Treatments Scheduled for Cayuga Lake’s South End

Cayuga Lake hydrilla update

Thanks to vigilant monitoring and effective treatment response, hydrilla (Hydrilla verticillata) is being controlled in Cayuga Inlet, Cascadilla Creek, Fall Creek, and around the south end of Cayuga Lake. To prevent further spread of this aggressive invasive aquatic species, the Tompkins County Hydrilla Task Force has developed a monitoring and treatment plan for summer and fall of 2021.

The U.S. Army Corps of Engineers Buffalo District (USACE Buffalo) plans to apply the aquatic herbicides fluridone (Sonar® H4C and Sonar Genesis) in Fall Creek beginning June 24^th. The Sonar H4C lake treatments and Sonar H4C Cayuga Inlet treatments will begin on July 1^st.  Spot treatments with Harpoon® Granular may be used in areas that regrow. A total of 10 H4C treatments will occur on Thursdays until at least September 1^st, within the approximately 100-acre project area around the lake’s south end and including Cayuga Inlet, Cascadilla Creek, and Fall Creek. The project area is divided into the following four treatment areas (see attached maps):

1. Fall Creek: 22.5 acres starting at Fall Creek from the SR 13 bridge to the confluence with Cayuga Lake including the lagoons at Stewart Park and the golf course, and an additional three other areas hydrologically connected to Fall Creek. This area will be treated with Sonar® Genesis and Sonar® H4C.
2. Cayuga Lake East: 55 acres at the southern end of Cayuga Lake offshore of Stewart Park and the Cornell Community Sailing Center. This area will be treated with Sonar® H4C.
3. Cayuga Lake West: 12.5 acres comprised of two different areas near Treman State Marine Park west of the confluence with Cayuga Inlet. This area will be treated with Sonar® H4C.
4. Cayuga Inlet: 9.8 acres comprised of four different areas within the Cayuga Inlet. This area will be treated with Sonar® H4C.

In all four treatment areas, the Sonar® H4C application will be split into a total of 10 treatments. For the Fall Creek and Cayuga Lake East treatment areas, the first two applications will occur at 20 parts per billion (ppb), followed by eight applications at 9 ppb for treatments 3 through 10. For the Cayuga Lake West and Cayuga Inlet treatment area, the first two applications will occur at 20 ppb, followed by eight applications at 13.75 ppb for treatments 3 through 10. The portion of the Fall Creek treatment area from SR bridge to the confluence with Cayuga Lake will also be treated with Sonar® Genesis to maintain a 2.5 ppb daily rate using an injection system.

Additionally, if there is any significant re-establishment of hydrilla beds in the 100-acre project area, those beds may be spot treated with Harpoon® Granular, on or about the week of August 16, 2021. These spot treatment applications are not expected to exceed approximately 10 acres.  Signs will be posted along the lake when the herbicide is applied.

There are no restrictions for fishing, swimming, or livestock/pet water consumption at the proposed application rates of Sonar® H4C, Sonar® Genesis, and Harpoon® Granular.  There are restrictions for using water treated with Sonar® H4C and Sonar® Genesis for irrigation.  There are also potable water restrictions for water treated with Sonar® H4C, Sonar® Genesis, and Harpoon® Granular if treated water concentrations are above the thresholds indicated in Table 1.

Table 1 Water Use Restrictions

     * Applications of Sonar® H4C and Sonar® Genesis will be below the listed thresholds.

   ** Application of Harpoon® Granular will only exceed these concentrations in small spot treatment areas that are not expected to exceed a cumulative total of 10 acres for the season.

Key:

ppb = parts per billion

Notification signage

Sign locations are at ~100ft intervals at every shoreline within the treatment area that is publicly accessible via some kind of regularly used public park or walking trail. This amounts to a total of 193 signs that will be posted.  55 signs will be posted along Fall Creek and mention both the Sonar H4C and Sonar Genesis treatments and 138 signs that will just have the Sonar H4C description in those areas where this is the only treatment (East and West Lake Treatment Areas and the Cayuga Inlet area). There will be signs posted at Treman State Park Marina at all of the dock access points even though there are no plans to treat the marina.

Questions about herbicide concentrations following application should be directed to Katie Evans Katie.Evans@wsp.com , Richard Ruby Richard.J.Ruby@usace.army.mil, or

Angel Hinickle AHinickle@tompkins-co.org .

Product labels are available for review on Solitude Lake Management’s website:

https://www.solitudelakemanagement.com/product-labels-new-york-updates. Hard copies of the labels can be requested by contacting Katie Evans Katie.Evans@wsp.com .

Following each treatment, Tompkins County Health Department and Bolton Point will conduct water quality monitoring and the results will be posted to the County website https://tompkinscountyny.gov/health/eh/water/hydrilla

For questions concerning water use please contact:

Tompkins County Health Department

55 Brown Road

Ithaca, NY 14850

607-274-6688

Tompkins County Hydrilla Task Force Cayuga contact information

Angel Hinickle, Tompkins County Soil & Water Conservation District AHinickle@tompkins-co.org             Richard Ruby, USACE Buffalo District Richard.J.Ruby@usace.army.mil

Tompkins County Health Department https://tompkinscountyny.gov/health/eh/water/hydrilla

Hilary Lambert & Jenn Tufano, Cayuga Lake Watershed Network steward@cayugalake.org  & programs@cayugalake.org

Contact: Hilary Lambert steward@cayugalake.org