Crescent Cove to receive algaecide treatment for HAB

July 29, 2022| Environment

By: Holly Odgers

A plan to treat a portion of Hopatcong Borough's Crescent Cove with the algaecide, GreenClean, to combat a harmful algal bloom (HAB) has been approved by the Lake Hopatcong Commission, Lake Hopatcong Foundation, Hopatcong Borough, and the New Jersey Department of Environmental Protection (NJDEP).

The NJDEP first reported a HAB in Crescent Cove in mid-July. It was reported at the ADVISORY level, which warns against direct contact with the water.

A combination of extreme heat and occasional heavy rain along with the shallow, still waters of the cove can lead to high water temperatures and elevated phosphorus levels, which allow cyanobacteria to proliferate or bloom, creating HABs. Cyanobacteria can cause neurological and digestive issues in humans and pets if ingested, and a skin rash with external contact.

In response to the Crescent Cove HAB, a one-time treatment of the algaecide, GreenClean, will be applied to approximately five acres (two acres each in the northern and southern ends, and an additional acre along the western shoreline). The treatment aims to reduce the concentration of cyanobacteria, but that relief may only last a short period of time. Addressing the cause and not just the symptoms is critical in preventing future HABs on the lake.

GreenClean is a registered algaecide in New Jersey, which has previously been utilized on Lake Hopatcong as part of a grant, which evaluated different technologies to control, prevent, or mitigate HABs. It uses a stabilized hydrogen peroxide paired with peroxyacetic acid, making it a more environmentally friendly alternative to copper-based algaecides.

Criteria are currently being developed to evaluate future possible treatments of GreenClean and future HAB incidents around the lake will be addressed on a case-by-case basis.

The Lake Hopatcong Commission and the Lake Hopatcong Foundation have both authorized payments of up to $5,000 each for the treatment.

The Lake Hopatcong Commission, Lake Hopatcong Foundation, Hopatcong Borough, and the NJDEP are working closely together to get all necessary permits and approvals for treatment to occur as soon as possible. 

The treatment application will be executed by SOLitude Lake Management and pre- and post-treatment monitoring will be performed by Princeton Hydro.