Lake Hopatcong is more famous than ever, but not necessarily in a good way.

An in-depth Washington Post article on global warming featured New Jersey and the lake in particular as endangered by climate change. The lake’s unusual early-season algal bloom was cited as result of the unusually hot, wet weather. The investigative report was reprinted on Sunday, Aug. 18, on the front page of a number of Newhouse newspapers, including two that serve parts of New Jersey, The Star-Ledger and The Express-Times and shared extensively online.

On Monday, Aug. 19, the Lake Hopatcong Commission entertained public comment on the lake’s problems from a standing room only audience at the Lake Hopatcong Station.

Chair Ron Smith had a problem holding public comment to the limit of two minutes each as various residents presented their concerns and suggestions for solutions.

Before the audience weighed in, the commission’s environmental consultant, Fred Lubnow of Princeton Hydro, reported on the latest results of water testing.

Some of the tests are remarkably low-tech, he noted. Turbidity is measured using the Secchi disk, invented in 1865 and still the gold standard. The disk shows the water is darker and more opaque this year. After the five-foot drawdown, the algal blooms hit the lake in June and limited light penetration.

Lubnow pointed out the immediate cause of the algal bloom was heavy rain followed immediately by very hot days early in the season.

He pointed out Princeton Hydro has been monitoring the outflow from the stream that flows from Weldon Quarry into the lake. The amount of phosphorus coming into the lake is equal to the amount from a nearby control stream. Residents have been concerned that siltation from a broken pipe at the quarry might be a contributing factor to the algal bloom because the bacteria in the bloom feed on phosphorus.

Lubnow said the amount of phosphorous is not the only criteria. He said the percentage of dissolved oxygen influences the amount of bacteria, because with less dissolved oxygen more phosphorous is released. So there is actually more phosphorous to feed the bacteria coming out of the stream from the quarry than from the control stream.

The commission addressed the options for controlling other sources of phosphorous as well.

Alternatives for Control

New Jersey’s prohibition against phosphorous in fertilizers should eliminate runoff from lawns, but there is phosphorous occurring naturally in the soil and it enters storm water from other sources. The commission discussed purchasing a vacuum truck for cleaning storm drains in all four of the surrounding towns.

Jefferson and Hopatcong already have these machines. Jefferson Mayor Eric Wilsusen, an alternate member of the commission, said one that could be shared would be beneficial. He noted there are 11,000 storm drains in the sprawling township, which has the most lake frontage.

Hopatcong Mayor Mike Francis said Hopatcong doesn’t have the manpower to clean every storm drain that needs it. He said he would support a shared vacuum truck.

Hopatcong Mayor Mike Francis talks about problems in Crescent Cove. (Photo: Jane Primerano)

Lubnow said multi-chambered baffle boxes, which are installed in many storm drains, settle particulates which remove between 30 and 40 percent of the phosphorous. He said sleeves and filter socks are being installed in storm drains at the bottom of drainage areas to remove even more.

He also said using strong oxidizers rather than copper-based algicides, which used to be the standard, is more effective. The copper-based algicides actually release the toxins from the blue-green algae.

Sewering the areas of the lake not currently sewered is frequently discussed.

Wilsusen noted Jefferson did a sewer study in 2002 and there are many hurdles to sewering there.

One of the hurdles is that Lake Shawnee is in the Highlands Preservation area, and sewering is not allowed. Commissioner Robert Tessier, the state Department of Community Affairs representative, said the Highlands Council could be approached about an exemption.

Another possibility is connecting 50 homes on Crescent Cove to the Hopatcong Borough sewers.

Francis said that is part of his plan to clean up the cove, which is known as the most problematic on the lake. It is where Francis and others want to use sterile grass carp to eat the leafy weeds that plague the cove.

Lubnow said enforcement of septic management ordinances, such as the one Jefferson has, helps keep phosphorous out of the lake. He said pumping out the tank keeps the leach field from becoming anoxic. Francis said Hopatcong has a draft of a septic management ordinance.

The algal bloom has kept the lake weeds down over the summer because it has kept sunlight from penetrating.

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