Hydrilla - An Invasive Water Weed
In 2017, Authority staff confirmed the presence of hydrilla in the Manasquan Reservoir. Hydrilla is a highly aggressive submersed aquatic invasive plant. If left unmanaged, hydrilla has the potential to clog water intakes, impair water quality including dissolved oxygen, inhibit recreational activities, and impact habitat for fish, waterfowl and other wildlife within the Reservoir and wetlands.
SOLitude Lake Management was hired in August 2017 to survey, assess, and map the extent of hydrilla and other problem weeds in the Manasquan Reservoir and adjacent wetlands. The Authority received the SAV delineation report in November 2017. The survey report indicates that hydrilla was observed at 65% of the survey sites in the Reservoir. The complete 2017 Manasquan Reservoir SAV Delineation Report is available here.
Based on this information, the Authority hired Princeton Hydro in April 2018 to prepare an Aquatic Plant Management Plan for the Manasquan Reservoir. This plan will be available in early 2019.
2018 Manasquan Reservoir Boat Launch Hydrilla Treatment
In June 2018, the Authority will initiate a 4-acre pilot herbicide application to manage the hydrilla infestation at the Reservoir boat launch. The herbicide selected, Sonar H4C, is a slow-release pelletized formula, and contains the active ingredient fluridone. The EPA Human Health Benchmarks for Pesticides states that fluridone presents a negligible risk to human health and the environment when applied according to its legally allowed uses and label directions. Following treatment with Sonar there will be no water use restrictions for water consumption, fishing, fish consumption or swimming. While the label carries a restriction for irrigation for concentrations above 5 ppb, the anticipated herbicide concentration in the water inside of the pilot area will vary slightly. Herbicide concentration monitoring will be conducted within and outside the pilot area. The Authority expects the results outside the pilot area, and specifically near the intakes, to be non-detectable at <1 ppb. Results will be posted on the Authority’s hydrilla webpage: www.njwsa.org/hydrilla.
The herbicide application is expected to begin on or about June 7th . There will be one application per month through October. The NJ licensed pesticide applicator for this project is Black Lagoon from Bordentown, NJ. Signage will be posted at the boat launch during and after application. The Authority has developed educational signage to post in the same locations.