Crescent Cove HAB to be Treated with Algaecide

The Lake Hopatcong Commission in an emergency meeting approved a plan Tuesday, July 26, to treat a portion of Hopatcong Borough’s Crescent Cove with a chemical algaecide to battle a rapidly developing harmful algal bloom.

The New Jersey Department of Environmental Projection has agreed to expedite permits for the application of algaecide GreenClean, said lake commission administrator Colleen Lyons.

The target date for the application is Aug. 8, she said.

In 2019, Lake Hopatcong was one of 70 New Jersey lakes to be affected by HABs, which occur when cyanobacteria increase at such a rate the water turns an oily green. High levels of the bacteria can trigger human health effects.

The commission will contribute $5,000 for the treatment, with an additional $5,000 coming from the Lake Hopatcong Foundation. Commission Chairman Ronald Smith said the cost of this treatment could be covered thorough future state grants.

The 2019 HAB resulted from a combination of heavy rains followed by several days of 90-plus degree temperatures.

Fred Lubnow of Princeton Hydro, the lake’s environmental consultant, said in recent weeks the lake region had duplicated that pattern. The United States Geological Survey recorded about 6 inches of rain between June 4 and July 23.

A week of 90 degree weather in mid-July was also present, Lubnow said.

The Crescent Cove HAB developed over a couple weeks, he said.

In early July, reading of bacteria levels found a level of 107,000 cells per milliliter, by July 15, the level had reached 207,000 and by July 26, over 700,000, Lubnow said.

The DEP issued an “advisory” for Crescent Cove, which cautions people about the health impact of contact with the water, and could lead to beach closings and other restricted uses.

Crescent Cove, a narrow shallow, closed, slow-water cove, is affected by among the lake’s highest population density, Lubnow said. The borough’s efforts to add sewers along the lake are an important effort to reduce the level of polluted run-off entering the lake.

Smith said the Aug. 8 action is a one-time treatment of Crescent Cove to knock down the HAB.

Further such singular HABs around the lake will be addressed on a case-by-case basis, he said.