Swimming Restricted At Some Lake Hopatcong Beaches, Due To Harmful Algal Blooms

ROXBURY TOWNSHIP, NJ — A popular beach in North Jersey has been closed since last week, while environmental officials monitor potentially-toxic levels of bacteria in the water.

The Hopatcong State Park Beach remains unaccessible for swimmers, as officials issued an advisory for a Harmful Algal Bloom, or HAB, on July 18. And, the Lake Hopatcong Foundation said that Crescent Cove, Byram Cove, and River Styx are also closed for swimming as of Thursday afternoon, July 25.

The nearby historic fountain is also shut down — two days after community members celebrated turning it back on.

These HAB advisories are issued when the New Jersey Department of Environmental Protection can confirm that the concentration of Cyanobacteria in the water is high enough to pose a moderate risk of adverse health effects, and an increased potential for toxins above public health thresholds.

Residents are also urged to keep children and pets away from the affected bodies of water, and advised against kayaking, wading, and eating fish from any waterway that's under an advisory. Advisories also close public bathing beaches.

You can see the results of the latest water samples on the DEP's website, which includes information closures or restrictions throughout the state.

The next level up from an advisory is a warning, meaning HAB has been confirmed with a high risk of adverse health effects due to high toxin levels. Warnings also close public bathing beaches, with the possibility of recommendations against recreation in affected areas.

Individual algal cells cannot be seen with the unaided eye; however, they can form large, visible colonies called blooms. Harmful algal blooms are made up of colonies of toxic cyanobacteria (also known as blue-green algae).

According to environmental officials, they usually multiply and bloom when water is warm, stagnant and filled with nutrients from sources such as septic systems, wastewater treatment plants and fertilizer runoff.