Algaecide results in Crescent Cove

August 19, 2022| Environment

By: Kyle Richter

On August 9, 2022, SOLitude Lake Management applied a one-time treatment of the algaecide, GreenClean, to approximately five acres within Crescent Cove in response to ADVISORY Level Harmful Algal Blooms (HABs) reported in the northern and southern ends of the cove in July.

The treatment was funded by the Lake Hopatcong Foundation and the Lake Hopatcong Commission, who worked in close partnership with Hopatcong Borough and the New Jersey Department of Environmental Protection (NJDEP).

GreenClean is a registered algaecide in New Jersey, which uses a stabilized hydrogen peroxide paired with peroxyacetic acid, making it a more environmentally friendly alternative to copper-based algaecides.

The GreenClean treatments, which were applied to two acres each in the northern and southern ends of Crescent Cove, and an additional acre along the western shoreline, did result in the reduction of the severity of HABs in those areas. Pre- and post-treatment sampling conducted by Princeton Hydro at three sampling locations, showed reductions in cell counts of 25% at the northern end of the cove, 28% along the western shore, and 50% at Crescent Cove Beach at the southern end. These reductions, however, were not enough to lower area HAB alerts from the ADVISORY level.  

Excess phosphorus along with the extremely hot and dry conditions we have been experiencing may all have contributed to the limited effectiveness of this treatment.

The Lake Hopatcong Foundation and the Lake Hopatcong Commission are currently developing a set of criteria to evaluate HAB conditions to guide future treatments on Lake Hopatcong. In addition, reducing phosphorus levels in Lake Hopatcong with long-term solutions such as sanitary sewers and stormwater management remains a primary focus and is critical in minimizing future HABs on the lake.