Lake Lily Green with Algae, Grass, Herbicide May Be Solution

CAPE MAY POINT — Lake Lily is not green with envy this summer but green with algae growth and weed.
An application of two types of herbicide may be the only cure.
Francine Nietubicz, chairperson of the Friends of Lake Lily Committee said the lake has three distinct problems, all of which thrive in the nutrient-rich waters fed by fertilizer runoff from lawns and the droppings of Canadian Geese. The lake waters have high phosphorus and nitrogen, she said, a problem that must be addressed as a long-term solution.
She said 27 storm drains feed into the lake.
Three types of weeds have invaded Lake Lily:
• Eurasian Watermilfoil: dense mats of tall grasses growing from the lake bottom that form curtains resulting in poor water flow and inhibiting the action of the aeration system. The weeds are so dense that the algae are lying on top of it. Watermilfoil can be controlled by hand weeding by divers, introduction of vegetative-eating grass carp (very effective but not allowed by the state Department of Environmental Protection in lakes larger than 10 acres) or application of appropriate herbicides after DEP permitting (best applied in the spring), harvesting or rototilling but this results in fragmenting the plants which is the way they propagate.
• Filamentous Algae: floating mats of single-celled plants that join together and float to the surface. It can be controlled by raking out the mats and disposing of it away from the lake to prevent nutrients from re-entering the lake as it decays (effective but labor intensive), application of appropriate herbicides after DEP permitting which is effective but may need to be repeated during a season and is best applied when bloom is new.
• Watermeal and Duckweed: small green free-floating plants that can cover the surface of the lake very quickly and is the most difficult of the plants to eradicate. It can cause fish kills and block sunlight from reaching the lake bottom thereby limiting photosynthesis and depriving the lake of oxygen. It can be controlled by skimming it from the lake surface using swimming pool-type mesh nets, introduction of grass carp (not allowed by DEP) or application of appropriate herbicides after DEP permitting (best applied in the spring).
The Friends of Lake Lily Committee has concluded that it would be best to use the herbicide approach even though they have never wanted to put chemicals in the lake, said Nietubicz. The herbicides are not harmful to fish and other wildlife or to humans but would possibly kill the lilies, she said.
“We are willing to live with that, as they can be replaced if desired,” said Nietubicz.
She said algae are the most noticeable problem and the one that causes great consternation, it is the weed most likely to need a short-term solution. The only way to control this quickly is by raking out the mats and finding a place to remove it to, said Nietubicz.
The committee spoke with Mayor Carl Schupp who said Public Works did not have a large enough staff to go into the lake and rake away the debris, so herbicide may be the solution.
A Clean-Flo aeration system was installed in the lake in 2007. The prediction was the algae would disappear in two years. Clean-Flo systems are designed to reduce high bacteria counts, algae and weed growth and build-ups of organic material such as leaves and bird droppings.
Eurasian Watermilfoil growing from the bottom of the lake to the surface has diminished the effectiveness of the aeration system, said Nietubicz. She said technicians from Clean-Flo said algae in the lake are dead explaining the brown hue.
“Nobody can understand how that happened,” she said.
Even after treatment, the algae could come back, said Nietubicz.
She said she was very disappointed when the Division of Fish and Wildlife said grass carp could not be introduced to a lake as large as Lake Lily. She said even though the fish would be sterile and unable to reproduce, there is fear they could escape to other waterways. She said the carp could grow to 80 pounds and live as long as 15 years.
Canadian Geese have been less of a problem this summer because a male swan has been chasing them out of the lake. The ideal number of geese for the lake is six or less.
Nietubicz said she counted 150 geese on the lake two years ago. A consultant said they may have turned the lake into a “cesspool.”
Is Lake Lily in a state of eutrophication, trying to fill itself in or becoming a marsh?
“Eutrophication is really the normal, natural process for a lake, especially a seepage lake,” she said.
Eutrophication is defined as excessive nutrients causing excessive plant growth in a lake.
The lake is not fed by a spring. A recent water analysis from Lake Lily, after a heavy rainstorm, showed the lake’s phosphorus and nitrate levels were very high.
Two sprayings of herbicide in the spring are anticipated, she said. In the long term, a filter system may need to be placed on storm drains, residents may be asked to use low phosphorus-low nitrogen fertilizer or plant flower beds between lawns and drains to filter rain water.
Those interested in contributing to a fund for cleaning up the lake, may send a tax-deductible donation to Friends of Lake Lily, PO Box 32, Cape May Point, NJ 08212.
Lake Lily was dredged in 2004 at a cost of $1 million. A pit was excavated at the former magnesite factory to hold water and 26,000 cubic yards of bird droppings from the bottom of the lake.
The lower end of lake near the island was not dredged and is now composed of two feet of muck and two feet of water, said Nietubicz.